WO2022231587A1

WO2022231587A1 - Vibration of microfluidic device

Info

Publication number: WO2022231587A1
Application number: PCT/US2021/029747
Authority: WO
Inventors: Napoleon J. Leoni; Omer Gila
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2022-11-03
Anticipated expiration: 2023-10-28

Abstract

A digital microfluidic device comprising a consumable microfluidic receptacle including a first plate and a second plate spaced apart from the first plate, the microfluidic receptacle to receive a polar liquid droplet between the respective first and second plates. The second plate comprises a first portion to receive charges from a charge applicator, to produce an electric field between the second plate and the first plate at a position adjacent the liquid droplet to pull the liquid droplet through the microfluidic receptacle. A vibration element is coupled to a portion of the receptacle to apply a mechanical vibration acceleration force, at least during droplet movement, which is substantially greater than a gravitational acceleration force.

Description

VIBRATION OF MICROFLUIDIC DEVICE

Background

[0001] Microfluidic devices are revolutionizing testing in the healthcare industry. Some microfluidic devices comprise digital microfluidic technology, which may employ circuitry to move fluids.

Brief Description of the Drawings

[0002] FIG. 1 A is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces to an example consumable microfluidic receptacle.

[0003] FIGS. 1 B and 1C each are a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces to an example consumable microfluidic receptacle, which is mounted within a frame with the frame mounted relative to a support via a retention element.

[0004] FIG. 2A is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces relative to an example consumable microfluidic receptacle.

[0005] FIG. 2B is a diagram including a top plan view schematically representing an example consumable microfluidic receptacle.

[0006] FIG. 3A is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces to an example consumable microfluidic receptacle including a substrate, which includes an anisotropic conductivity layer.

[0007] FIGS. 3B and 3C are each a diagram including a side view schematically representing an example conductive element including an array of conductive particles.

[0008] FIG. 4 is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces to an example consumable microfluidic receptacle including a substrate, which includes a passive electrode array.

[0009] FIG. 5 is an isometric view schematically representing an example addressable airborne charge depositing unit including a needle within a cylinder. [0010] FIG. 6A is a diagram including a side view schematically representing an example addressable airborne charge depositing unit, including first and second charge units.

[0011] FIG. 6B is a diagram including a side view schematically representing an example addressable airborne charge depositing unit, including a charge building element and a pair of charge neutralizing elements.

[0012] FIG. 6C is a diagram including a side view schematically representing an example two-dimensional addressable charge depositing unit in charging relation to a portion of a consumable microfluidic receptacle.

[0013] FIG. 7A is diagram including a sectional end view schematically representing an example addressable airborne charge depositing unit, including a corona wire and array of individually controllable electrode nozzles.

[0014] FIG. 7B is a diagram including a top view schematically representing an example array of individually controllable electrode nozzles of an example addressable airborne charge depositing unit.

[0015] FIG. 8A is a diagram including a side view schematically representing an example electrode control element.

[0016] FIG. 8B is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration forces to an example consumable microfluidic receptacle which is in releasable contact with an example electrode control element.

[0017] FIG. 8C is a diagram including an isometric view schematically representing an example two-dimensional array of individually controllable electrodes, prior to releasable contact relative to, a portion of a consumable microfluidic receptacle.

[0018] FIG. 9 is a diagram including a side view schematically representing an example device and/or example method to apply mechanical vibration to an example microfluidic device including a microfluidic receptacle and a charge applicator incorporated into the device.

[0019] FIG. 10A is a block diagram schematically representing an example fluid operations engine.

[0020] FIG. 10B is a block diagram schematically representing an example control portion.

[0021] FIG. 10C is a block diagram schematically representing an example user interface.

[0022] FIG. 11 is a flow diagram schematically representing an example method of applying charges to cause electrowetting movement of droplets.

Detailed Description

[0023] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.

[0024] At least some examples of the present disclosure are directed to providing a consumable microfluidic receptacle by which digital microfluidic operations can be performed in an inexpensive manner and/or more effectively. In some examples, a charge applicator is to apply charges to cause an electric field which induces electrowetting movement of a droplet within and through the microfluidic receptacle. In some examples, a vibration element is in vibrating relation to the microfluidic receptacle to apply a mechanical vibration acceleration force to the droplet at least during the electrowetting movement. This vibration force may enhance velocity of the droplet movement, uniformity of the velocity, precision in starting or terminating an instance of droplet movement, etc. In some examples, the applied mechanical vibration acceleration forces may be substantially greater than a gravitational acceleration force. In some examples, such substantially greater forces may comprise a mechanical vibration acceleration force which is at least about 50 g’s, such as about 5000 percent greater than a gravitational acceleration force (e.g. 1 g). In some examples, this relationship may be expressed as the applied mechanical vibration acceleration force being at least one order of magnitude greater than a gravitational acceleration force.

[0025] In some examples, the charge applicator may comprise an addressable airborne charge depositing unit which may be brought into spaced apart, charging relation to the plate (e.g. second plate) of the receptacle in order to deposit airborne charges onto the plate. In some examples, the charge applicator may comprise an electrode control element (including an array of spaced apart electrode contacts) which may be brought into releasable contact with, and charging relation to, the plate (e.g. second plate) in order to deposit charges onto the second plate of the receptacle. In some examples, the substrate of the second plate may comprise a passive electrode array or an anisotropic conductivity layer, which may facilitate migration of charges across the second plate.

[0026] However, in some examples, the charge applicator may be incorporated into the microfluidic receptacle, such as being part of a second plate of the microfluidic receptacle. In some such examples, the charge applicator may sometimes be referred to as being an on-board charge applicator and may comprise an addressable array of active electrode contacts.

[0027] In one aspect, the term “charges” as used herein refers to ions (+/-) or free electrons. In some examples, the addressable airborne charge depositing unit may sometimes be referred to as a non-contact charge depositing unit, as a non- contact charge head, and the like. In some examples, the electrode control element may sometimes be referred to as a releasable contact, electrode control element. In some examples, the plate may sometimes be referred to as a sheet, a wall, a portion, and the like. Moreover, it will be apparent that in some examples, the consumable microfluidic receptacle may form part of and/or comprise a microfluidic device, such as a digital microfluidic device. In some examples, the consumable microfluidic receptacle may sometimes be referred to as a single use microfluidic receptacle, or as being a disposable microfluidic receptacle.

[0028] In some examples, each droplet comprises a small, single generally spherical mass of fluid, such as may be dropped into the consumable microfluidic receptacle. As described above, the entire droplet is sized to be movable via electrowetting forces. In sharp contrast, dielectrophoresis may cause movement of particles within a fluid, rather than movement of an entire droplet of fluid. Some further example details are provided below.

[0029] In some examples, the charge applicator may apply the charges having a first polarity and/or an opposite second polarity, depending on whether the charge applicator is to build charges on the plate or is to neutralize charges on the plate. The first polarity may be positive or negative depending on the particular goals, while the second polarity will be the opposite of the first polarity.

[0030] In some examples, the movement of droplets (caused by electrowetting forces) may occur between adjacent target positions along passageways within a microfluidic receptacle of a microfluidic device, with the target positions corresponding to locations at which the charges are directed from one of the example charge applicators.

[0031] Via at least some of example arrangements, such as those in which the charge applicator is a non-contact charge depositing unit or an electrode control element is releasably contactable relative to the second plate of the receptacle, the consumable microfluidic receptacle (of a microfluidic device) may omit on board control electrodes (e.g. electrically active electrodes) which would otherwise be used to cause microfluidic operations such as moving, merging, and/or splitting droplets within a microfluidic device. Moreover, in these particular examples, by providing the example charge applicator to cause an electric field on a portion of the consumable microfluidic receptacle, the consumable microfluidic receptacle may omit inclusion of a printed circuit board and circuitry (e.g. active control circuitry) typically associated with digital microfluidic devices. This arrangement may significantly reduce the cost of the consumable microfluidic receptacle of the microfluidic device and/or significantly ease its recyclability. [0032] Moreover, because some example consumable microfluidic receptacles of the present disclosure omit such electrically active control electrodes (for causing electrowetting movement) and omit complex circuitry which is typically directly connected to the control electrodes via conductive traces, the example consumable microfluidic receptacle of the present disclosure is not limited by the limited space constraints typically arising from a one-to-one correspondence between control electrodes and the complex control circuitry. Absent such space constraints, a greater number of target positions along the passageways of the example microfluidic receptacle may be used, which may increase the precision by which microfluidic operations are performed, with a resolution (e.g. number of target positions for a given area) of such target positions corresponding to the capabilities (e.g. resolution) that the example charge applicator (e.g. non-contact addressable charge depositing unit or electrode control element) can deposit charges. By being able to re-use such an example charge applicator over-and- over again with a supply of disposable or consumable microfluidic receptacles, this example arrangement greatly reduces the overall, long term cost of using digital microfluidic devices while significantly conserving valuable electrically conductive materials.

[0033] In some examples, the consumable microfluidic receptacle may be used to perform microfluidic operations to implement a lateral flow assay and therefore may sometimes be referred to as a lateral flow device. In some examples, the consumable microfluidic receptacle also may be used for other types of devices, tests, assays which rely on or include digital microfluidic operations, such as moving, merging, splitting, etc. of droplets within internal passages within the microfluidic device.

[0034] In at least some examples, when the plate (e.g. a second plate) is not conductive, at least some example charge applicators of the present disclosure stand in sharp contrast to some digital microfluidic devices which include an on board, array of control electrodes (connected to a power supply) which operate at a constant voltage and which are constantly changing the number of charges in the electrodes to maintain a desired voltage while the droplet is pulled into the induced electric field. However, via at least some example charge applicators of the present disclosure, charges are deposited on an exterior portion of a second plate of a consumable microfluidic receptacle such that a generally constant amount of charges may be maintained while a voltage at this second plate changes when a liquid droplet propagates into an induced, electric field zone and, at the same time, changes its intensity.

[0035] However, in some examples a digital microfluidic device which incorporates an on-board charge applicator with a microfluidic receptacle can provide the simplicity of being an integrated unit, which does not involve access to or availability of a separate charge applicator.

[0036] Regardless of the particular type of example charge applicator of the present disclosure used to apply charges to induce electrowetting movement, at least some examples of the present disclosure comprise a vibration element to apply mechanical vibration acceleration forces to a droplet at least during electrowetting movement.

[0037] These examples, and additional examples, are further described and illustrated below in association with at least FIGS. 1 A-11 .

[0038] FIG. 1 A is a diagram including a side view schematically representing an example arrangement 20 (and/or example method) to control electrowetting movement. In some examples, the arrangement 20 may comprise a digital microfluidic (DMF) device 25 including a consumable microfluidic receptacle 52 and a charge applicator, either of which may be provided separately in some examples. For illustrative simplicity and general applicability of FIGS. 1 A-2A, at least some example charge applicators are shown and described in association with at least FIGS. 3A and 5-9.

[0039] As shown in FIG. 1 A, the consumable microfluidic receptacle 52 comprises a first plate 110 and a second plate 120 spaced apart from the first plate 110, with the spacing between the respective plates 110, 120 sized to receive and allow movement of a liquid droplet 130, such as a polar liquid droplet (e.g. conductive droplet). In some examples, the consumable microfluidic receptacle may form a portion of a microfluidic device, and according sometimes may be referred to as a microfluidic device or portion thereof. [0040] As shown in FIG. 1A, in some examples each of the respective first and second plates 110, 120 comprise an interior surface 111 , 121 , respectively, and each of the respective first and second plates 110, 120 comprise an exterior surface 112, 122, respectively.

[0041] In some examples, at least the interior surface 111 , 121 of the respective plates 110, 120 may comprise a planar or substantially planar surface. However, it will be understood that a passageway 119 defined between the respective first and second plates 110, 120 may comprise side walls, which are omitted for illustrative simplicity. The passageway 119 may sometimes be referred to as a conduit, cavity, and the like.

[0042] It will be understood that the first and second plates 110, 120 may form part of, and/or be housed within a frame, such as the frame 205 of the microfluidic device 200 shown in FIG. 2B.

[0043] In some examples, the interior of the passageway 119 (between plates 110, 120) may comprise a filler such as a dielectric oil, while in some examples, the filler may comprise air. In some such examples, the filler may comprise other liquids which are immiscible and/or which are electrically passive relative to the droplet 130 and/or relative to the respective plates 110, 120. In some examples, the filler may affect the pulling forces (F), may resist droplet evaporation, and/or facilitate sliding of the droplet and maintaining droplet integrity.

[0044] As further shown in FIG. 1 A and as further described below, the application of charges 144B via second plate 120 causes an electric field E between the second plate 120 and the first plate 110, which induces electrowetting movement (e.g. pulling forces F) of droplet 130 to a new position within passageway 119 of the receptacle 52 corresponding to the location at which charges 144B were applied. Several examples by which the charges 144B may be produced and provided within second plate 120 (to cause electrowetting movement) are described below in context with several different example charge applicators, several different example second plates, etc. in association with at least FIGS. 1 B-9.

[0045] As further shown in FIG. 1A, in some examples the arrangement 20 comprises a vibration element 30 coupled relative to the at least the microfluidic receptacle 52. In some such examples, the vibration element 30 may comprise part of the microfluidic device 25, while in some examples the vibration element 30 may be considered to be independent of (but couplable relative to) the microfluidic device 25.

[0046] In at least some examples, the vibration element 30 produces mechanical vibration acceleration forces, as represented via the directional force arrows MV1 , MV2, MV3, MV4 in FIG. 1A. The directional force arrow MV1 represents such forces acting on an exterior surface 122 of the second plate 120 (e.g. a bottom plate) and in an orientation which is generally transverse to a plane P1 through which the receptacle 52 extends. In some instances, this orientation may sometimes be referred to as a vertically-oriented vibration force. The directional force arrow MV4 represents similar forces, except acting on an exterior surface 112 of the first plate 120 (e.g. a top plate) and in an orientation which is generally transverse to a plane P1 through which the receptacle 52 extends.

[0047] The directional force arrows MV2, MV3 represent similar mechanical vibration acceleration forces, except acting on a side portion 115 of the first plate 120 (e.g. a top plate) and/or a side portion 115 of the second plate 120 (e.g. a bottom plate) and in an orientation which is generally parallel to a plane P1 through which the receptacle 52 extends. In some instances, this orientation may sometimes be referred to as a lateral vibration force. It will be further understood that the side forces (e.g. MV2 and/or MV3) may be applied from any side(s) of the receptacle 52.

[0048] With regard to any of the vibration forces illustrated in FIGS, the directional arrows (e.g. MV1 , MV2, etc.) may represent application of the vibration forces in a concentrated area or in a much broader pattern across the applicable structure (e.g. exterior surface 122). The directional arrows (e.g. MV1 , MV2, etc.) also may represent that some form of coupling may be used, in some examples, between the vibration element 30 and the respective surface or portion of the receptacle 52. In at least some examples, this coupling maintains a direct, rigid or rigid-like connection between the vibration element 30 and the receptacle 52 (or portion of device 25) to ensure efficient/effective transmission of the mechanical vibration acceleration forces from the vibration element 30 to the receptacle 52 while minimizing (or preventing) energy loss in such transmission. [0049] FIG. 1 B is a diagram of an example arrangement 50 (e.g. example device and/or example method) to apply mechanical vibration forces as in the example of FIG. 1 A, except with a frame 53 releasably retaining the receptacle 52 and with the frame 53 mounted relative to a support 70 via a retention element 60. Accordingly, as shown in FIG. 1 B, a digital microfluidic device 25 (including microfluidic receptacle 52) is releasably secured within and relative to a frame 53. In some examples, the frame 53 may be rigid and the vibration element 31 A (like vibration element 30) may be secured directly to an outer surface or portion 59 of the frame 53. In some examples, the frame 53 may comprise spaced apart portions (e.g. walls, clamps, and the like) 54 which define a recess or other shape/structure to releasably retain the microfluidic device 25 therein. A bottom portion 58 of the frame 53 may be coupled relative to one side 61 A of the retention element 60, while an opposite side 61 B of the retention element 60 is secured to a support 70 via a base 64 and fasteners 66 such that the retention element 60 is interposed between the support 70 and the frame 53 (which holds the microfluidic device 25). In some examples, the retention element 60 may comprise a structure, such as but not limited to a sheet, of material which is flexible and resilient, and which may comprise metal or other materials. The orientation, size, shape, volume, and/or type of material of retention element 60 may be selected to enable movement of the frame 53 (and releasably retained receptacle 52) with minimal energy loss and with the retention element 60 implementing a desired resonance frequency relative to the applied mechanical vibrations and/or the microfluidic device 25.

[0050] Accordingly, the retention element 60 acts to retain (e.g. anchor) the frame 53 (which releasably retains the microfluidic receptacle 52 therein) relative to the support 70 in order to maintain a stable platform for microfluidic operations (and the applied vibration) of receptacle 52 but without interfering with (e.g. without damping or with minimal damping) the mechanical vibration acceleration forces being applied to the receptacle 52. [0051] As further shown in FIG. 1 B, in some such example arrangements which include retention element 60 to retain the frame 53 (and receptacle) relative the support 70, the vibration element 31 A may apply a lateral mechanical vibration acceleration force MV2 resulting in vibration-based lateral motion of the microfluidic device 52 in a first orientation (e.g. lateral) as indicated via directional motion arrow L. However, it will be understood that this lateral force is merely an example, and that forces may be applied in other desired orientations (e.g. vertical, other) via a vibration element suitably positioned to apply the mechanical vibration acceleration forces.

[0052] FIG. 1 C is a diagram of an example arrangement 80 (e.g. example device and/or example method) having at least some of substantially the same features and attributes as the example arrangement 50 of FIG. 1 B, except including a pair of retention element(s) 82, such as but not limited to the spaced apart, spring elements shown in FIG. 1 C. It will be understood that, while retention elements 82 may take a different form than retention element 60 in FIG. 1 B and may be implemented as multiple elements (instead of a single element), the retention elements 82 may comprise at least some of substantially the same features and attributes as retention element 60 (FIG. 1 B) and/or may comprise a further example implementation of retention element 60.

[0053] As shown in FIG. 1 C, each spring element 82 extends between, and is secured relative to, the bottom portion 58 of the frame 53 and the support 70. Each spring element 82 may comprise a size, shape, volume, and/or type of material selected to enable movement of the frame 53 (and releasably retained receptacle 52) with minimal energy loss and with the retention elements 82 (e.g. springs) implementing a desired resonance frequency relative to the applied mechanical vibrations and/or the microfluidic device 25.

[0054] As further shown in FIG. 1 C, in some examples such retention elements 82 may be implemented in association with mechanical vibration acceleration forces, such as MV2 (shown in FIG. 1 B) applied in a first orientation (e.g. lateral) and/or MV1 (FIG. 1 C) applied in a second orientation (e.g. vertical) transverse to the first orientation. As further shown in FIG. 1 C, the mechanical vibration applied in the second orientation (e.g. MV 1 ) may be implemented via a separate, second vibration element 31 B while the mechanical vibration applied in the first orientation is applied via the same first vibration element 31 A shown in FIGS. 1 B and FIG. 1 C.

[0055] With further reference to FIGS. 1A-1 C, in some examples just one of the examples mechanical vibration acceleration forces (e.g. MV1 , MV2, MV3, MV4, and the like) may be applied to the microfluidic receptacle or in some examples, some combination of the differently-oriented multiple mechanical vibration acceleration forces may be applied.

[0056] In some examples, the vibration forces may be applied in an alternating manner in which forces are applied in a first orientation (e.g. lateral) and then applied in a different orientation (e.g. vertical), or vice versa.

[0057] In some examples, the vibration element (e.g. 30, 31 A, 31 B) may comprise a piezoelectric transducer, while in some examples, the vibration element may comprise an eccentric motor. In some examples, the vibration element may comprise an acoustic element, which may comprise a voice coil and solenoid, in some examples.

[0058] In some examples, the vibration element (e.g. 30, 31 A, 31 B) may produce mechanical vibration acceleration forces which are substantially greater than a gravitational acceleration force. In some examples, such substantially greater forces may comprise a mechanical vibration acceleration force which is at least about 30 g’s (e.g. 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1 , 30.2, 30.3, 30.4, 30.5), which generally corresponds to the applied mechanical vibration acceleration force being 2900-3000 percent greater than a gravitational acceleration force (e.g. 1 g). In some such examples, the frequency of the applied vibration is at least about 200 Hz and an amplitude of vibration may comprise at least about 20 micrometers. The mechanical vibration acceleration force acting on the droplet 130 may be determined as an amplitude times (2 x p x frequency)². Using the above example values, the mechanical vibration acceleration force may be determined to be 0.00002 x (2 x p x 200)² which equals about 32 g’s.

[0059] In some examples, a substantially greater force may be expressed as the applied mechanical vibration acceleration force being at least one order of magnitude greater than a gravitational acceleration force (e.g. 1 g). [0060] In some examples, the frequency of the applied vibration may comprise at least about 600 Hz. In some examples, the amplitude of vibration may comprise at least about 50 micrometers, such as about 3 percent or more of the dimension (e.g. 1500 micrometers) of the droplet 130.

[0061] In some examples, the frequency of the applied vibration is within about 30 percent (e.g. 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1 , 30.2, 30.3, 30.4, 30.5) greater or 30 percent less than a resonance frequency of the consumable receptacle (e.g. 52) of the microfluidic device 25.

[0062] In some examples, via application of such mechanical vibration acceleration forces, a droplet velocity may be increased by a factor of at least 3, depending on at least some of the parameters described above and/or described later in association with at least vibration control engine 1440 in FIG. 10A.

[0063] In some examples, the mechanical vibration acceleration forces may be applied in association with operation of the microfluidic devices (e.g. application of charges) under a DC current or an AC current. In some examples, the changing polarity of charges applied via an AC current may help prevent charge buildup or charge traps in the hydrophobic layer and dielectric layers, which may enhance performance because such charge buildup in a dielectric layer/insulator may otherwise be difficult to remove and could interfere with drop movement. In some examples, the changing polarity of charges applied via an AC current also may help reduce drop contact line resistance, which may increase droplet velocity, promote uniformity of droplet velocity, and/or enhance precision in initiating or terminating droplet movement. Of course, as noted elsewhere, whether charges are applied via an AC current or via a DC current among the various examples throughout the present disclosure, the mechanical vibration acceleration forces applied via a vibration element (e.g. 30, 31 A, 31 B in FIGS. 1 A-1 C) may decrease a contact line resistance of a droplet within the passageway and may increase drop movement speed.

[0064] As represented by the directional force arrows MV1 , MV2, MV3, MV4 illustrated throughout the examples in association with at least FIGS. 1 A-9, it will be understood that the description of applying mechanical vibration acceleration forces with regard to FIGS. 1 A-1 B is equally applicable to the various examples described in association with at least FIGS. 1A-9.

[0065] FIG. 2A is a diagram including a side view schematically representing an example arrangement 100 (including at least microfluidic receptacle 102 and vibration element 30) and which comprises at least some of substantially the same features and attributes as the example arrangements 20, 50, 80 (including receptacle 52/microfluidic device 25 and vibration element 30, 31 A, 31 B) in FIGS. 1A-1 C), while including additional features and attributes as further described below. In some examples, receptacle 102 (FIG. 2A) may comprise one example implementation of receptacle 52 (e.g. FIGS. 1A-1 C) and include a first plate 110 and a second plate 160.

[0066] As shown in FIG. 2A, in some examples, a distance (D1 ) between the respective plates 110, 160 of receptacle 102 may comprise between about 50 to about 500 micrometers, between about 100 to about 150 micrometers, or about 200 micrometers. In some examples, the droplet 130 may comprise a volume of about less than a microliter, such as between about 10 picoliters and about 30 microliters. Flowever, it will be understood that in some examples, the consumable microfluidic device (including receptacle 102) is not strictly limited to such example volumes or dimensions.

[0067] In some examples, the first plate 110 may be grounded, i.e. electrically connected to a ground element 113, which is also later shown in other FIGS, such as element 113 in FIGS. 3A, 4, etc. In some examples, the first plate 110 may comprise a thickness (D4) of about 100 micrometers to about 3 millimeters, and may comprise a plastic or polymer material. In some examples, the first plate 100 may comprise a glass-coated, indium tin oxide (ITO). As noted later in association with at least FIG. 2B, the thickness (D4) of first plate 110 may be implemented to accommodate fluid inlets (e.g. 221 A, 223A, etc. in FIG. 2B), to house and/or integrate sensors into the first plate 110, and/or to provide structural strength. In some examples, the sensors may sense properties of the fluid droplets, among other information.

[0068] As further shown in FIG. 2A, instead of the entire first plate 110 being electrically conductive to serve as (or connect to ground), in some examples, the first plate 110 of the consumable microfluidic receptacle 102 may comprise an electrically conductive layer 115, by which the first plate 110 may be electrically connected to a ground element 113. In some such examples, the electrically conductive layer 115 may comprise a material such an indium titanium oxide (ITO) which is transparent and may have a thickness D8 on the order of a few tens of nanometers.

[0069] As further shown in FIG. 2A, in some examples, microfluidic receptacle 102 may comprise a first coating 137 on interior surface 111 of first plate 110 and/or a second coating 136 on interior surface 121 of second plate 160, with such coatings arranged to facilitate electrowetting movement of droplets 130 through the passageway 119 defined between the respective plates 110, 160. [0070] In some examples, at least one of the respective coatings 137, 136 may comprise a hydrophobic coating, while in some examples, at least one of the respective coatings 137,136 may comprise a low contact angle hysteresis coating. In some examples, a low contact angle hysteresis coating may correspond to contact angle hysteresis of less than about 30, 29, 28, 27, 26, 25, 24, 23, 22, 21 , or 20 degrees. In some examples, the contact angle hysteresis may comprise less than about 20, 19, 18, 17, 16, or 15 degrees. In some example implementations including coatings 137,136, an oil filler is provided within the passageways 219A-219E, which further enhances the effect of the coatings 137,136. In some examples, the coating 137 and coating 136 may have respective thicknesses of D6, D7 on the order of one micrometer, but in some examples the thicknesses D6, D7 can be less than one micrometer, such as a few tens of nanometers. In some examples, the thicknesses can be greater than one micrometer, such as a few micrometers.

[0071] As further shown in FIG. 2A, in some examples the second plate 160 may further comprise a dielectric layer 134. In some examples, the combination of the coating 136 and the dielectric layer 134 may correspond to a first portion 170 of the second plate 160.

[0072] As further shown in FIG. 2A, in some examples the second plate 160 may comprise a second portion 162, which as represented via dashed lines 167, may comprise one of a plurality of different structures (and associated features) as further described below in association with at least FIGS. 3A, 4, 8A-8B, 9. For instance, some examples of second portion 162 may comprise a substrate embodying anisotropic conductivity (e.g. FIGS. 3A, 4), some examples of second portion 162 may comprise a charge applicator (e.g. FIG. 9), etc. Regardless of the particular example implementation of second portion 162 of second plate 160, charges will be applied in a manner such that charges 144B become positioned at dielectric layer 134 as shown in FIG. 2A in a manner to create the electric field E and pulling forces F for electrowetting movement of the droplet 130.

[0073] As further shown in FIG. 2A, in some examples, the deposited charges 144 B exhibit a first voltage V1 , which may sometimes be referred to as an applied voltage. As previously noted, the particular manner in which the charges 144B are deposited are described further below with respect to the different example implementations of the second portion 162 of the second plate 160.

[0074] As shown in FIG. 2A, the deposited charges 144B are located at a target position shown in dashed lines T1 , which is immediately adjacent to the droplet 130. In some such examples, this target position may sometimes be referred to as a virtual electrode, at least to the extent that the dimensions/shape of the area over which the charges are deposited (and the applied voltage resides) may be viewed as being analogous to the dimensions/shape of an electrode pad, such as one of the electrode pads (e.g. 444A) of a respective one of the electrodes 442A, etc. of the passive electrode array 440 shown in FIG. 4.

[0075] As further represented in FIG. 2A, in some examples the deposited charges 144B are located at an interface 135 between the second portion 162 and the dielectric layer 134 (e.g. an inner surface of the dielectric layer 134) of the first portion 170 of the second plate 160.

[0076] With first plate 110 being grounded, counter negative charges 146A develop at the first plate 110 to cause an electric field (E) between the respective first and second plates 110, 160, which creates a pulling force (F) to draw the droplet 130 forward into the target position T1 . In some examples, at least part of this arrangement includes the liquid droplet 130 being conductive (i.e. polar) in at least some examples, such that counter-charges 146B develop within the droplet 130 relative to charges 146A (at first plate 111 ) and counter-charges 144C develop within the droplet 130 relative to charges 144B at interface 135 (between the dielectric layer 134 and the second portion 162) within the second plate 160. At least because of the charge differential between the charges 144B and 144C and between the charges 146A and 146B (which corresponds to a voltage differential between V1 and V2), a pulling force is created to pull the droplet 130 from the position (e.g. TO) into the target position T1. Stated differently, the droplet 130 is moved from one virtual electrode to the next/adjacent virtual electrode. Among other aspects, parameters (e.g. dielectric strength, thickness, etc.) associated with the dielectric layer 134 help to maintain the desired charge differential (or voltage differential) which induces the desired droplet movement. [0077] In some examples, the pulling force (F), which causes movement of droplet 130 upon inducing the electric field (E), may comprise electrowetting forces. In some such examples, the electrowetting forces may result from: (1 ) modification of the wetting properties of the interior surface 121 of second plate 160 and/or surface 111 of plate 111 upon application of the electric field (E); (2) counter charges introduced in the droplet 130, which may result from electrical conductivity within the droplet 130 in some examples and/or from induced dielectric polarization within the droplet 130 in some examples; and/or (3) a minimization of the electrical potential energy due to charges in the system including as an example the minimization of the energy due to the counter charges 146A (e.g. negative) and the charges 144A (144B) (e.g. positive) in the case of a non-conductive droplet.

[0078] In some examples, the deposited charges 144B at second plate 120 may comprise between on the order of tens of volts and on the order of a few hundred volts of charges on the second plate 160. In some examples, the deposited charges 144B may comprise 1000 Volts. In some examples, the deposited charges 144B will dissipate, e.g. discharge upon a charge applicator applying opposite charges (e.g. negative charges) via the second plate 160, such as at interface 135. As the droplet 130 moves into the area of the charges (i.e. the target position T1 ), the electric field E drops due to an increased dielectric constant occurring in the effective capacitor which is formed between the respective first and second plates 110, 160. [0079] It will be further understood that charges (e.g. 144B) deposited on the second plate 160 (by one of the example charge applicators) will be significantly discharged or at least be discharged to a level at which their voltage is significantly lower than the voltage to be applied before the next electrowetting- caused pulling movement of the droplet 130 occurs to the next target position T2. [0080] At least some aspects of implementing discharge of the charges (e.g. 144A, 144B) are further described later in association with at least FIGS. 5-8 regarding example implementations of a non-contact charge depositing unit, such as airborne charge depositing unit 355 in FIG. 3A.

[0081] In some such examples, at least some aspects applying the mechanical vibration in association with vibration element 30 may be implemented in association with a vibration control engine 1440 of a fluid operations engine 1400 (FIG. 10A), which in turn may comprise part of or be implemented in association with, control portion 1500 of FIGS. 10B-10C. Various aspects associated with the vibration control parameter are described further below and throughout various examples of the present disclosure.

[0082] With this general example arrangement in mind, further details regarding the dielectric layer 134 and relationships regarding second plate 160 are described below.

[0083] In some examples, the dielectric layer 134 may be an insulating material, comprising a resistivity of at least 10¹¹ Ohm-cm, and in some examples, at least 10¹³ Ohm-cm.

[0084] In considering the behavior of a voltage differential across at least the dielectric layer 134 of second plate 160, it will be understood that in at least some examples the droplet 130 is generally electrically conductive and therefore droplet 130 generally sits at a voltage close to ground. In some such examples, in this context the droplet 130 may be considered to be conductive, having a resistivity less than 10⁷ ohm-cm. Given this general conductivity of the droplet 130, it will be further understood that the above-described, the applied voltage differential occurs entirely (or substantially entirely) across material within the second plate 160 which exhibits dielectric properties, such as the dielectric layer 134. [0085] Moreover, as noted elsewhere among the various examples, of the present disclosure, materials of the dielectric layer 134 may exhibit compatibility with hydrophobic layer 136.

[0086] In some examples, the dielectric layer 134 may comprise a dielectric material having a thickness of at least about 10 micrometers (e.g. 9.7, 9.8, 9.9, 10.1 , 10.2, 10.3). In some examples, the dielectric layer 134 may comprise a dielectric material having a thickness of at least about 20 micrometers (e.g. 19.7, 19.8, 19.9, 20.1 , 20.2, 20.3). In some examples, the dielectric layer 134 may comprise a dielectric material having a thickness of at least about 50 micrometers (e.g. 49.7, 49.8, 49.9, 50.1 , 50.2, 50.3).

[0087] In some such examples, the dielectric material comprise a combination (e.g. hybrid) of organic material and inorganic materials, which may comprise coatings provided in liquid form and cured via many possible routes. In some such examples, the dielectric material of layer 134 may comprise monomers/prepolymers that contain inorganic silicon-oxygen groups as well as reactive organic functional groups. In at least some example implementations of such materials, the dielectric layer 134 may comprise a thickness of at least about 10 micrometers, about 20 micrometers, and so on as noted above.

[0088] In some examples, the other materials (from which dielectric layer 134 may be formed) may comprise films in a fluoropolymer class of materials.

[0089] In some examples, the second voltage V2 remains substantially stable at least during the droplet-movement time period. In some examples, a velocity of droplet movement may comprise between about 1 mm/second and 30 mm/second. Accordingly, in some examples which an electrode has a length (e.g. D2 in FIG. 1 ) of about 3 millimeters, one example droplet-movement time period may comprise between about 0.1 and about 3 seconds. In one example, the time period may comprise about 2 seconds.

[0090] With further reference to FIG. 2A and the deposited charges 144B at interface 135, in some examples, similar deposited charges also may be used to neutralize charges at interface 135 (or also on exterior surface 172 of) second plate 160, such as after a desired droplet movement has occurred. In particular, in some arrangements, such subsequent deposited charges may be used to neutralize residual charges so as to prepare the microfluidic receptacle (e.g. portion of a microfluidic device) to receive a deposit of fresh charges in preparation of causing further electrowetting movement of the droplet 130 to a next target position (e.g. T2).

[0091] In some examples, such microfluidic operations to be performed via the consumable microfluidic receptacle 102 and an appropriate charge applicator (e.g. 355 in FIG. 3A, 4; 600 in FIG. 5; 640 in FIG. 6A; 670 in FIG. 6B; 715 in FIG. 6C; 800 in FIG. 7A; 900 in FIG. 7B; 1050/1150 in FIG. 8A-7C; 1250 in FIG. 9) may be implemented in association with a control portion, such as but not limited to control portion 1500 in FIG. 10B and/or in association with a fluid operations engine 1400 in FIG. 10A.

[0092] FIG. 2B is a diagram including top plan view schematically representing an example microfluidic device 200. In some examples, the microfluidic device 200 comprises at least some of substantially the same features and attributes as the consumable microfluidic receptacle 52, 102 in FIGS. 1 A-1 C, 2A. In particular, in some examples, the microfluidic receptacle 52, 102 in FIGS. 1A-1 C, 2A may comprise at least a portion of the example microfluidic device 200.

[0093] As shown in FIG. 2B, the microfluidic device 200 comprises a frame 205 within which is formed an array 215 of interconnected passageways 219A, 219B, 219C, 219D, 219E, with each respective passageway being defined by a series of target positions 217. In some examples, the respective passageways 219A- 219E are defined between a first plate (e.g. 110 in FIGS. 1 A, 2A) and a second plate (e.g. 120 in FIG. 1A, 160 in FIG. 2A), with each target position 217 corresponding to a target position (e.g. T1 or T2) shown in FIG. 2A at which a droplet (e.g. 130 in FIG. 2A) may be positioned. In some examples, each target position 217 may comprise a length of about 500 to about 1500 micrometers while in some examples the length may be about 750 to about 1250 micrometers. In some examples, the length may be about 1000 micrometers. Meanwhile, in some examples, each target position 217 may have a width commensurate with the length, such as the above-noted examples.

[0094] As previously noted in association with FIGS. 2A-2B, in some examples the respective target positions 217 and the passageways 219A-219E do not include active control electrodes (and related circuitry) for moving droplets 130. Rather, droplets 130 are moved through the various passageways 219A, 219B, 219B, 219D, 219E via electrowetting forces caused by applying charges (e.g. 144B in FIGS. 1A, 2A) from a charge applicator, such as one of the charge applicators , as described in association with FIG. 3A, 4, 5-8C. Accordingly, via the use of such an externally-applied electric field, the droplet(s) 130 move through the passageways via electrowetting forces without any active control electrodes (and related circuitry) lining the paths defined by the various passageways 219A-219E. Flowever, in some examples, such charges 144B also may be applied via an on-board charge applicator, such as described later in association with at least FIG. 9.

[0095] As further shown in FIG. 2B, at least some of the respective target positions 217, such as at positions 221 A, 221 B, 223A, and/or 223B may comprise an inlet portion which can receive a droplet 130 to begin entry into the passageways 219A-219E to be subject to microfluidic operations such as moving, merging, splitting, etc. In some examples, some of the example positions 221 A, 221 B, 223A, 223B may comprise an outlet portion, from which fluid may be retrieved after certain microfluidic operations.

[0096] It will be understood that in some examples, the consumable microfluidic device 200 may comprises features and attributes, in addition to those described in association with at least FIGS. 1A-2A. For example, in some instances and with further reference to at least FIG. 2B, prior to receiving droplets 130, the microfluidic device 200 may comprise at least one fluid reservoir R at which various fluids (e.g. reagents, binders, etc.) may be stored and which may be released into at least one of the passageways 219A-219E. In some examples, release of such reagents or other materials may be caused by the same externally-caused electrowetting forces as previously described to cause movement of droplet 130. Moreover, in some examples, at least some of the passageways 219A-219E may form or define a lateral assay flow device in which some reagents, etc. may already be present at various target positions 217 within a particular passageway (e.g. 219A-219E) such that upon movement of various droplets 130 relative to such target positions 217 may result in desired reactions to effect a lateral flow assay. However, in some examples, the microfluidic device 200 does not store any liquids on board, and any liquids on which microfluidic operations are to be performed are added, such as in the example inlet locations 221 A, 221 B, 223A, 223B, as previously described.

[0097] Via the electrowetting movement of the respective droplets within the passageways 219A-219E, various microfluidic operations of moving, merging, splitting may be performed within microfluidic device 200 to cause desired reactions, etc. With this in mind, in some examples a portion of the consumable microfluidic device 200 may comprise at least one sensor (represented by indicator S in FIG. 2B) to facilitate tracking the status and/or position of droplets within a microfluidic device, as well as for determining a chemical or biochemical result ensuing from the various microfluidic operations, such as merging, splitting, etc. In some such examples, such sensors may be incorporated into the first plate 110 (FIG. 2A) so as to not interfere with the deposit of charges, migration of charges, neutralization of charges, etc. occurring at or through the second plate 160 (FIG. 2A). In some examples the sensor(s) may include external sensors, like optical sensors. In some such examples, such external sensors may be used to sense attributes of a fluid retrieved from an above-described outlet portion. [0098] In some examples, such microfluidic operations to be performed via the microfluidic device 200 and/or via an associated charge applicator (e.g. FIGS. 3A-9) may be implemented in association with a control portion, such as but not limited to control portion 1500 in FIG. 10B and/or in association with a fluid operations engine 1400 in FIG. 10A.

[0099] In some examples, as shown in FIG. 2A, each target position (e.g. T1 ,T2, etc.) may comprise a length (D2) which may comprise a length expected to be approximately the same size (e.g. length D2) as the droplet 130 to be moved. In view of the example volumes of droplets noted above, the length (D2) of each target position (e.g. T1 , T2, etc.) may comprise between about 50 micrometers to about 5 millimeters, and may comprise a width similar to its length in some examples. In some examples, the target position also may sometimes be referred to as a droplet position. In some examples, each of the respective droplet positions also may sometimes be referred to as corresponding to the position, size, and/or shape of the below-described virtual electrodes (i.e. location where charges 144B are deposited to induce electrowetting movement) of the second plate or actual electrodes of the second plate 160.

[00100] In some examples, the length (D2) of the droplet in passageway 119 may sometimes be referred as a length scale of the droplet (or target position of a droplet). In sharp contrast to some other devices which utilize an array of active control electrodes and which involve spacing between adjacent control electrodes because of manufacturing limitations, in at least some examples of the present disclosure, the target positions (e.g. T1 , T2) may be immediately adjacent each other with virtually no spacing therebetween. Accordingly, at least some examples of the present disclosure do not face at least some of the challenges in moving droplets that may otherwise be posed by a distance between adjacent electrodes in such devices employing active control electrodes.

[00101] In some examples, the example arrangements of the present disclosure to cause electrowetting movement of droplets stand in sharp contrast to some microfluidic devices which rely on dielectrophoresis to produce movement of particles. At least some such dielectrophoretic devices comprise a distance between control electrodes (of a printed circuit board which form one of the microfluidic plates) which is substantially greater (e.g. 10 times, 100 times, etc. ) than a length scale (e.g. size) of a particle within a liquid to be moved. For instance, the distance between control electrodes (in some dielectrophoretic devices) may be on the order of hundreds (i.e. 100’s) of micrometers, whereas the length scale of such particles may comprise on the order of hundreds (i.e. 100’s) nanometers. In some such devices, the distance between electrodes in a dielectrophoretic device may sometimes be referred to as a length scale of such electrodes or as a length scale of the gradient (i.e. gradient length scale).

[00102] For comparison purposes to some dielectrophoretic devices, a droplet of liquid to be moved via electrowetting forces in at least some examples of the present disclosure may comprise a thickness between a first plate 110 and second plate 120 of about 200 micrometers, and a length (or width) extending across a target position (e.g. T1 , T2) (i.e. droplet position) of about 2 millimeters, in some examples. In sharp contrast, dielectrophoresis may cause movement of a particle within a mass of fluid, where such particle may be about 100 nanometers diameter (or length, width, or the like) and many particles may reside within a droplet of liquid. However, the dielectrophoretic device does not generally cause movement of an entire fluid mass.

[00103] FIG. 3A is a diagram including a side view schematically representing an example arrangement 301 including a consumable microfluidic receptacle 302 in which a second portion 362 of a second plate 360 may comprise an anisotropic conductivity layer 340. In some examples, the example arrangement 301 may include a charge applicator, which comprises a non- contact charge depositing unit 355 in some examples. In some examples, the example consumable microfluidic receptacle 302 may comprise, and/or be employed via, at least some of substantially the same features and attributes as the examples previously described in association with at least FIGS. 1A-2B. Accordingly, while FIG. 3A omits vibration element (e.g. 30, 31 A, 31 B) for illustrative simplicity, it will be understood from the appearance of the directional force arrows (e.g. MV1 , MV2, MV3, MV4) that at some of the previously-described mechanical vibration acceleration forces are to be applied in the context of the example arrangement 301 via a vibration element (e.g. 30, 31 A, 31 B, other). [00104] In some examples, like the second plate 160 of microfluidic receptacle 102 in FIG. 2A, the second plate 360 of receptacle 302 in FIG. 3A comprises a first portion 170 comprising hydrophobic layer 136 and dielectric layer 134. Meanwhile, as further shown in FIG. 3A, second plate 360 comprises a second portion 362 which comprises one example implementation of the second portion 162 of second plate 160 in the arrangement of FIG. 2A. As shown in FIG. 3A, in some such examples the second portion 362 of second plate 360 comprises an anisotropic conductivity layer 340. In the particular example of second plate 360 in FIG. 3A, the second portion 362 may sometimes be referred to as a substrate, which supports the first portion 362.

[00105] In some examples, as shown in FIG. 3A, the anisotropic conductivity layer 340 comprises a conductive-resistant medium 345 (e.g. partially conductive matrix) within which an array 332 of conductive elements 334 is oriented generally perpendicular to the plane (P2) through which the entire anisotropic conductivity layer 340 generally extends. In some examples, the conductive-resistant medium 345 (e.g. matrix) may comprise a bulk resistivity of about 10¹¹ Ohm-cm to about 10¹⁶ Ohm-cm. In some such examples, the conductive elements 334 may comprise a conductivity at least two orders of magnitude greater than a bulk conductivity of the conductive-resistant medium 345. In some examples, the resistant-conductive medium 345 of the layer 340 may comprise a plastic or polymeric materials, such as but not limited to, materials such as polypropylene, Nylon, polystyrene, polycarbonate, polyurethane, epoxies, or other plastic materials which are low cost and available in a wide range of conductivities. In some examples, a bulk conductivity (or bulk resistivity) within the desired range noted above may be implemented via mixing into the plastic material some conductive carbon molecules, carbon black pigments, carbon fibers, or carbon black crystal. In some examples, the conductive-resistant medium 345 may comprise a resistivity of less than 10⁹ Ohm-cm in the perpendicular direction (direction B) to the plane P2, and a larger lateral resistivity (e.g. lateral conductivity) of at least 10¹¹ Ohm-cm (direction C along plane P2). Accordingly, the lateral conductivity is at least two orders of magnitude less than the conductivity of the conductive-resistant medium 345 in the direction perpendicular to the plane P2 (FIG. 3A). Further details regarding the anisotropic layer 340 are later described below.

[00106] As further shown in FIG. 3A, in some examples, the addressable charge depositing unit 355 (e.g. a charge applicator) may be brought into a spaced apart relationship relative to the exterior surface 372 of the second plate 360 of the example arrangement, as represented by the distance D5. In some examples, the distance D5 may comprise about 0.25 millimeters (e.g. 0.23, 0.24, 0.25, 0.26, 0.27) to about 2 millimeters (e.g. 1 .9, 1 .95, 2, 2.05. 2.1 ). In some such examples, the addressable charge depositing unit 355 may be supported by, or within, a frame 133 and the consumable microfluidic receptacle 302 may be releasably supportable by the frame 133 to place the consumable microfluidic receptacle 302 and the addressable charge depositing unit 355 into charging relation with each other. [00107] As further shown in FIG. 3A, upon the consumable microfluidic receptacle 302 and the addressable charge depositing unit 355 being appropriately positioned relative to each other, the addressable charge depositing unit 355 may emit airborne charges 352 toward and onto the exterior surface 372 of the second plate 360, which may then be referred to as initially deposited charges 144A. In some examples, the initially deposited charges 144A exhibit a first voltage V1 , which may sometimes be referred to as an applied voltage. [00108] As shown in FIG. 3A, the emitted charges 352 are directed to a target position shown in dashed lines T1 , which is immediately adjacent to the droplet 130. In some such examples, this target position may sometimes be referred to as a virtual electrode, at least to the extent that the dimensions/shape of the area over which the charges are deposited (and the applied voltage resides) may be viewed as being analogous to the dimensions/shape of an electrode pad, such as one of the electrode pads (e.g. 444A) of a respective one of the electrodes 442A, etc. of the passive electrode array 440 shown in FIG. 4. [00109] As further represented in FIG. 3A, the deposited charges 144A at exterior surface 372 of second plate 360 travel through the second portion 362 of the second plate 360 to an interface 135 between the second portion 362 (e.g. an inner surface of second portion 362) and the dielectric layer 134 (e.g. an inner surface of the dielectric layer 134) of first portion 170 of second plate 260, as represented by charges 144B. Upon such migration to interface 135, the charges 144B exhibit substantially the same voltage (e.g. V1 ) at the interface 135 as the charges 144A at exterior surface 122.

[00110] At least some aspects of implementing discharge of the charges (e.g. 144A, 144B) are further described later in association with at least FIGS. 5- 8 regarding example implementations of the charge depositing unit 355.

[00111] As later described in association with at least FIGS. 5-8 and with further reference to at least FIG. 3A, this applied first voltage V1 may be achieved via developing an internal voltage (e.g. V3 in FIG. 3A) within the charge depositing unit of sufficient strength (e.g. 2900V) such that with an electrode control voltage (VC) (e.g. via a grid, electrode hole, and the like) of the charge depositing unit 355 set at a desired value (e.g. 700 V) for a selectable period of time (e.g. 0.625 seconds), the exterior surface 372 of second plate 360 becomes charged (via charges 144A) to the first voltage V1 of 700V (e.g. applied voltage). As previously noted in association with at least FIGS. 1 A-2A, a voltage differential (VD) between the interface 135 and the droplet 130 adjacent the interior surface 121 of the second plate 420 results in the electric field E between the second plate 360 and the first plate 110, and this arrangement causes electrowetting movement of the droplet 130 from the position shown in FIG. 3A to the target position T1 aligned with applied charges 144A, 144B.

[00112] Thereafter, in some examples, the charge depositing unit 355 may be used to discharge the charges 144B at interface 135 by setting the internal voltage (e.g. V3 in FIG. 3A) of the charge depositing unit 355 to an elevated voltage of an opposite polarity (e.g. -1600V) and the control voltage (VC) to 0 Volts for a period of time (e.g. 0.5 to 0.6 seconds), which results in the T 1 locations of interface 135 being discharged to 0 Volts (or a minimal value). In order to move the droplet 130 from target position T1 to T2, the charge depositing unit 355 is moved into a position to be aligned with the target location T2 over a period of time (e.g. 0.5 to 0.6 seconds), and then the process (e.g. depositing fresh charges 144A to create a voltage differential and electric field E, electrowetting droplet movement) repeats in order to move droplet 130 from position T1 to position T2. With many iterations via this arrangement, a velocity of droplet movement may be achieved that falls within a range between about 0.5 mm/second and 200 mm/second. In some examples, the velocity of droplet movement may comprise between about 1 mm/second to about 30 mm/second. In some examples, the velocity of droplet movement may comprise between about 5 mm/second to about 20 mm/second. In some examples, the velocity of droplet movement may comprise at least about 10 mm/second.

[00113] It will be understood that in some examples, the addressable charge depositing unit 355 may be mobile and the microfluidic receptacle 302 may be stationary while performing microfluidic operations, while in some examples, the addressable charge depositing unit 355 may be stationary and the microfluidic receptacle 302 is moved relative to the addressable charge depositing unit 355 during microfluidic operations. In some examples, the frame 133 (FIG. 3A) may including portions, mechanisms, etc. which may facilitate relative movement between the consumable microfluidic receptacle 302 and the charge depositing unit 355. At least some such examples may be implemented in association with one of the addressable charge depositing units as described in association with at least FIGS. 5-8C.

[00114] In some examples, both of the addressable charge depositing unit 355 and the microfluidic receptacle 302 are stationary during microfluidic operations, with the addressable charge depositing unit 355 being arranged in a two-dimensional array to deposit charges in any desired target area of the microfluidic receptacle 302 in order to perform a particular microfluidic operation or sequence of microfluidic operations. At least some example implementations of such a two-dimensional array may comprise at least some of the substantially the same features and attributes as described in association with at least FIGS. 6C and/or 8C.

[00115] In some examples, such microfluidic operations to be performed via the consumable microfluidic receptacle 302 and an addressable charge depositing unit (e.g. 355 in FIG. 3A) may be implemented in association with a control portion, such as but not limited to control portion 1500 in FIG. 10B and/or in association with a fluid operations engine 1400 in FIG. 10A.

[00116] In some examples, the relative permittivity of the conductive- resistant medium 345 of the anisotropic layer 340 may be greater than about 20 (e.g. 19.5, 19.6, 19.7, 19.8, 19.9, 20, 20.1 , 20.2, 20.3, 20.4, 20.5). In some examples, the relative permittivity may be greater than about 25, 30, 35, 40, 45 50, 55, 60, 65, 70, or 75. In some instances, the relative permittivity may sometimes be referred to as a dielectric constant. Among other attributes, providing such relative permittivity may result in a lower voltage drop across the second plate 360. In some examples, the relative permittivity of the second plate 360 in the direction of the plane P2 may comprise lower than about 10. In some examples, it may comprise about 3.

[00117] As noted above, in some examples, the anisotropic layer 340 may comprise a low lateral conductivity (i.e. a conductivity along the plane P2, such as represented via directional arrow C) with a resistivity of at least 10¹¹ Ohm-cm (similar to the bulk conductivity). In some examples, this resistivity along the plane P2 (i.e. lateral conductivity) may comprise about 10¹⁴ Ohm-cm.

[00118] In some examples, the anisotropic conductivity layer 340 may comprise a high conductivity perpendicular (direction B) to the plane P, such as a resistivity which is on the order of, or less than, 10⁹ Ohm-cm. In some examples, this resistivity may comprise 10⁶ Ohm-cm. In at least some examples, the resistivity perpendicular to the plane P2 is at least about two orders of magnitude different from (e.g. lower) than the resistively along or parallel to the plane P2. In some such examples, this relatively high conductivity perpendicular to the plane P2 may sometimes be referred to as vertical conductivity with respect to the plane P2. [00119] In comparison to the relatively high conductivity of the conductive resistant medium 345 perpendicular to the plane P2 (direction B), the above- noted relatively low lateral conductivity (direction C) of the conductive resistant medium 345 may effectively force travel of the charges (applied by the addressable charge depositing unit 355) to travel primarily in a direction (B) perpendicular to the plane P, such that the electric field E acting within the passageway 119 (i.e. conduit) may comprise an area (e.g. x-y dimensions) which are similar to the area (e.g. x-y dimensions) of each application of charges from the charge depositing unit 355 directed to a specific target position (e.g. T1 , T2, etc.).

[00120] As shown in FIG. 3A, via the example anisotropic conductivity layer 340 of second plate 360, the conductive elements 334 are aligned generally parallel to each other, in a spaced apart relationship, in an orientation generally the same as the direction (arrow B) which the charges 144A at the exterior surface 372 (of second plate 360) are to travel through second portion 362 of second plate 360 to reach the interface 135 with the dielectric layer 134 of first portion 170 of second plate 360. While the respective conductive elements 334 are shown as being oriented perpendicular to the plane P2, it will be understood that in some examples the conductive elements 334 may be oriented at a slight angle (i.e. slanted) which not strictly perpendicular.

[00121] Moreover, in some examples, as shown in FIG. 3B, each respective conductive element 334 may comprise an array 347 of smaller conductive particles 348 which are aligned in an elongate pattern to approximate a linear element of the type shown as element 334 in FIG. 3A. The array 347 of elements 348 (e.g. particles) may sometimes be referred to as a conductive path. In some examples, the conductive particles 348 may comprise metal beads with each bead ranging from 0.5 micrometers to about 5 micrometers in diameter (or a greatest cross-sectional dimension). In some such examples, these smaller conductive particles 348 may be aligned during formation of the anisotropic layer 340 via application of a magnetic field until the materials (e.g. conductive particles, conductive-resistant medium) solidify into their final form approximating the configuration shown in FIGS. 3B-3C. In contrast to the bulk resistivity of the conductive-resistant medium 345 of a resistivity of at least on the order of 10¹¹ Ohm-cm, the elongate pattern formed by array 347 of conductive particles 348 may comprise a resistivity of less than 10⁹ Ohm-cm in some examples. In some examples, the conductive particles 348 may comprise conductive materials, such as but not limited to iron or nickel. In some examples in which the conductive particles 348 are not in contact with each other, such particles 348 may be spaced apart by a distance F1 as shown in FIG. 3C, with such distances being on the order of a few nanometers in some examples. In some examples, the material (e.g. polymer) forming the conductive-resistant medium 345 of the anisotropic layer 340 of the second plate 360 is interposed between the respective conductive particles 348 of the array 347 (e.g. forming the elongate pattern) defining elements 334. In some such examples, because of this very small dimension F1 between at least some of the conductive particles 348, the conductive-resistance medium 345 interposed between the conductive particles 348 (and which would other exhibit a resistivity of at least on the order of 10¹¹ Ohm-cm in some examples) may comprise a conductive bridge (between adjacent particles 348) having a length less than about a micrometer and as such, may exhibit a much smaller resistivity which is several (e.g. 2, 3, or 4) orders of magnitude less than the resistivity otherwise exhibited by the conductive-resistant medium 345. Accordingly, even when some conductive resistant medium 345 is interspersed between some of the aligned conductive particles 348, the elongate pattern (e.g. array 347) of the conductive particles 348 still exhibits an overall conductivity perpendicular to the plane P2 (through which the second plate 120 extends) which comprises at least two orders of magnitude higher (e.g. greater) than the lateral conductivity along the plane P2.

[00122] In some examples, because of the anisotropic conductivity arrangement within the second portion 362 of the second plate 360, the second plate 360 exhibits a response time which is substantially faster than if the second portion 362 (i.e. substrate) were otherwise made primarily dielectric material or made of a partially conductive material without the conductive elements 334.

[00123] In one aspect, the anisotropic conductivity configuration of the second portion 362 of second plate 360 either may enable faster electrowetting movement of droplets 130 through passageway 119 due to higher electrical field on the droplet resulting in higher pulling forces and/or may permit use of thicker second plates (e.g. 160 in FIG. 2A, 360 in FIG. 3A), as desired (i.e. increasing the thickness of second plate 160, 360). In one aspect, providing a relative thick/thicker second portion of the second plate 160, 360 enables better structural strength, integrity, and/or better mechanical control of the gap between interior surface 111 of the first plate 110 and the interior surface 121 of the second plate 160, 360. In some examples, the second plate 160, 360 may comprise a thickness (D3) of about 30 micrometers to about 1000 micrometers. In some examples, the thickness (D3) may comprise about 30 micrometers to about 500 micrometers. In some examples, at least the second portion 162, 362 (i.e. substrate) of the second plate 160, 260 may sometimes be referred to as a charge-receiving layer and sometimes may be referred to as an anisotropic conductivity layer.

[00124] In one aspect, the anisotropic conductivity configuration (e.g. layer 340) forming second portion 362 of second plate 360 in FIG. 3A stands in sharp contrast to at least some anisotropic conductive films (ACF) which may resemble a tape structure and involve the application of high heat and high pressure, which in turn may negatively affect the overall structure of the consumable microfluidic receptacle, such as but not limited to, any sensitive sensor elements or circuitry within the first plate 110. Moreover, at least some anisotropic conductive films (ACF) may be relatively thin and/or flexible such that they are unsuitable to stand alone as a bottom plate of a microfluidic device because they may lack sufficient structural strength and durability.

[00125] As further shown in FIG. 3A, in some examples, the consumable microfluidic receptacle 302 may comprise spacer element(s) 309 at periodic locations or non-periodic locations between the first plate 110 and the second plate 360 to maintain the desired spacing between the respective plates 110, 360 and/or to provide structural integrity to the microfluidic receptacle 302. In some examples, the spacer element(s) 309 may be formed as part of forming one or both of plates 110, 360, such as via a molding process. It will be understood that such spacer element(s) 309 may form part of any of the other example microfluidic receptacles of the present disclosure.

[00126] While FIGS. 3A-7B are described primarily with respect to a charge applicator embodied as an example charge depositing unit (e.g. 355), it will be understood that other example charge applicators, such as the example electrode control element 1050, 1150 (FIGS. 8A-8C) may be used to apply charges in charging relation to a consumable microfluidic receptacle to cause electrowetting movement in the manner described throughout at least some examples of the present disclosure. Similarly, FIG. 9 provides an example charge applicator 1261 which is incorporated within a microfluidic device 1200 as to be on-board with, and secured as part of, a microfluidic receptacle 1202.

[00127] FIG. 4 is a diagram 400 including a side view schematically representing an example consumable microfluidic receptacle 402. In some examples, the example consumable microfluidic receptacle 402 may comprise, and/or be employed via, at least some of substantially the same features and attributes as the examples previously described in association with at least FIGS. 1A-3A, except with receptacle 402 comprising a second portion 462 (e.g. substrate) of a second plate 460 which comprises a passive electrode array layer 421 formed as an array of passive electrodes.

[00128] In some examples, as shown in FIG. 4, the passive electrode layer 421 comprises a conductive-resistant medium 447 (e.g. partially conductive matrix) within which an array 440 of electrodes 442A, 442B, 442C, 442D, 442E, 442F, etc. in which each respective electrode is oriented to be electrically conductive generally perpendicular to the plane (P2) through which the entire array 440 generally extends. In some examples, the conductive-resistant medium 447 (e.g. matrix) may comprise a bulk resistivity of about 10¹¹ Ohm-cm to about 10¹⁶ Ohm- cm. In some such examples, the electrically conductive electrodes (e.g. 442A, 442B, 442C, 442D, 442E, 442F) may comprise a conductivity at least two orders of magnitude greater than a bulk conductivity of the conductive-resistant medium 447.

[00129] In some such examples, the passive array 440 of electrodes (e.g. 442A, 442B, 442C, 442D, 442E, 442F) and matrix 447 may be formed as a printed circuit board or similar circuitry structure.

[00130] In some examples, each respective electrode (e.g. 442A, 442B, 442C, 442D, 442E, 442F) of the array 440 comprises a pair of pads 444A, 444B which are disposed at opposite ends of a column 445. In some instances, the column 445 of each respective electrode may be referred to as being interposed between the respective pads 444A, 444B of each respective electrode. As further shown in FIG. 4, in some examples the respective electrodes (e.g. 442A, 442B, etc.) of the array 440 are arranged in a side-by-side relationship and spaced apart from each other by a distance D12. In particular the outer edge of the pads (e.g. 444A, 444B) of one electrode (e.g. 442A) are spaced apart from the outer edge of the pads (e.g. 444A, 444B) of another electrode (e.g. 442B) by the distance D12, with a portion of the conductive-resistant medium 447 interposed between the outer edge of the pad (e.g. 444B) of one electrode (e.g. 442A) and the outer edge of the pad (e.g. 444B) of another electrode (e.g. 442B). Via this arrangement, each electrode (e.g. 442A-442F) of the array 440 is electrically independent of the other respective electrodes (e.g. 442A-442F) of the array 440.

[00131] In addition, each of the respective electrodes (e.g. 442A-442F) of the array 440 is passive, i.e. are not in electrical connection to (or communication with) any electrical circuitry, any power source, etc. Stated differently, each of the respective electrodes (e.g. 442A-442F) are isolated to be an independent electrically conductive element by which charges 144A may be conducted from exterior surface 472 of second plate 460 to interface 135 (represented as charges 144B) in order to create a voltage differential between V1 and V2 (across the dielectric layer 134) at a desired target position (e.g. T1 , T2, etc.) within the passageway 119 of the receptacle 400.

[00132] It will be understood that the electrodes 442A-442E shown in FIG. 4 are merely representative and that the electrodes of array 440 may extend in multiple orientations to comprise a two-dimensional array such as at least some of the examples, as described in association with at least FIGS. 2B, 6C, etc.

[00133] As further shown in FIG. 4, in a manner similar to that shown in at least FIGS. 1 A-1 B and 3A, in some examples a deposit of charges 144A (e.g. from a non-contact charge depositing unit 355, as in FIG. 3A) onto a selected electrode 442C (at exterior surface 472 of second plate 460) results in charges 144B at interface 135 of second plate 460 to induce the electric field E between the first and second plates 110, 460 to cause electrowetting movement of droplet 130 from the position shown in FIG. 4 to the target position T1 in a manner similar to that described with respect to at least FIGS. 1 A-1 B and 3A. In one aspect, the deposited charges 144A at exterior surface 472 at pad 444A of electrode 422C correspond to a first voltage V1 (e.g. similar to FIGS. 1A-1 B, 3A), while the charges 144B at interface 135 (aligned with pad 444B of electrode 422C) of second plate correspond to a second voltage V2 (e.g. similar to FIGS. 1A-1 B, 3A).

[00134] As previously noted, FIGS. 5-7B provide several example implementations of a non-contact charge depositing unit, such as charge depositing unit 355 (FIG. 3A).

[00135] FIG. 5 is an isometric view schematically representing an example addressable charge depositing unit 600. In some examples, the addressable charge depositing unit 600 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable charge depositing units described in association with at least FIGS. 1 A-4.

[00136] As shown in FIG. 5, the addressable charge depositing unit 600 comprises a needle 607. The needle 607 extends at least partially through, and is exposed at, one end 605 of a cylinder 602, with the needle 607 being spaced apart from the inner wall surface 609 of the cylinder 602. Upon applying an electrical signal, a high voltage (e.g. V3 in FIG. 3A) may be caused at the end of the needle 607, which in turn generates airborne charges 633 oriented to migrate toward a second plate (e.g. 360 in FIG. 3A) of a consumable microfluidic receptacle (e.g. 302 in FIG. 3A). The generated airborne charges 633 may be positive (as shown) or negative, depending on the particular goals (e.g. building charge, neutralizing charge, etc.) for the consumable microfluidic receptacle 102. In some examples, the cylinder 602 may be electrically connected to a ground element 613 and a third voltage (e.g. V3) applied to the needle 607 may be at least one order of magnitude greater than a first voltage V1 (e.g. deposited charges 144A in FIG. 2A) to occur at the exterior surface (e.g. 372 in FIG. 3A) of a second plate (e.g. 360 in FIG. 3A). In some such examples, the third voltage (V3) at needle 607 may comprise between about 1000 Volts to about 5000 Volts. [00137] Flowever, in some examples, the cylinder 602 is not grounded but rather an electrical signal is applied to cause the cylinder 602 to exhibit an alternate first voltage, with the third voltage at the needle 607 being substantially greater than the alternate voltage. In one such example implementation, the third voltage at needle 607 may comprise about 4000 Volts while the alternate first voltage at the cylinder 602 may comprise about 1000 Volts, while the first plate 110 is grounded. [00138] The addressable charge depositing unit 600 may be mobile, and moved relative to a stationary microfluidic device (e.g. consumable microfluidic receptacle), or the addressable charge depositing unit 600 may be stationary, and the microfluidic device (e.g. consumable microfluidic receptacle) may be moved relative to the addressable charge depositing unit 600. In either case, via such relative movement, the addressable charge depositing unit 600 may selectively generate airborne charges 633 to cause electrowetting movement of droplets within and through a consumable microfluidic receptacle, with the addressable charge depositing unit 600 being operated to generate negative or positive charges, depending on particular goals to build charges or neutralize charges. [00139] As further shown in FIG. 5, in some examples the addressable charge depositing unit 600 may comprise a grid 610 located at end 605 of the cylinder 602 which may be connected to its own power supply or a power supply to which the cylinder 602 is connected. Via the grid 610 and needle 607, the charge unit 600 may produce charges in an AC mode in which the needle 607 and grid 610 may alternate between producing positive and negative charges. In some such examples, the volume of positive and negative charges may not be proportional. In some such examples, the needle 607 may be operated at 3000 Volts and the grid 610 may be operated at 500 Volts.

[00140] FIG. 6A is a diagram 640 including a side view schematically representing an example addressable charge depositing unit 645. In some examples, the addressable charge depositing unit 645 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable charge depositing units described in association with at least FIGS. 1A-4. In some examples, the addressable charge depositing unit 645 comprises a first charge unit 652 and a second charge unit 654, each of which may generate airborne charges having a first polarity or an opposite second polarity, as desired. In some examples, the respective charge units 652, 654 may comprise and/or sometimes be referred to as an ion head, ion-generating head, and the like. For example, if the addressable charge depositing unit 645 were moved in a first direction (directional arrow M), the first charge unit 652 could emit airborne charges of a first polarity 653B (e.g. negative in some examples) to deposit charges in order to neutralize any residual charges present at second plate (e.g. 360 in FIG. 3A). Next, the following second charge unit 654 can emit airborne charges of an opposite second polarity 653A (e.g. positive in this example) to deposit and build charges at the exterior surface (e.g. 372 in FIG. 3A) of the second plate (e.g. 360 in FIG. 3A) in order to cause an electric field (as represented by directional arrow E) between the respective second and first plates (e.g. 360 and 110). This electric field (E) may induce electrowetting movement of droplets 130 within passageways of a consumable microfluidic receptacle for microfluidic operations. [00141] Alternatively, upon moving the addressable charge depositing unit 645 in an opposite second direction (directional arrow N), the second charge unit 654 may generate airborne charges having the first polarity (e.g. negative) 653B to deposit charges in order to neutralize any residual charges present at second plate 120. Next, the following first charge unit 652 can emit airborne charges of an opposite second polarity (e.g. positive in this example) 653A to deposit and build charges at the exterior surface (e.g. 372 in FIG. 3A) of the second plate (e.g. 360 in FIG. 3A) in order to cause an electric field (between the respective second and first plates 360, 110) to induce electrowetting movement of droplets 130 within passageways of a consumable microfluidic receptacle of a microfluidic device.

[00142] Accordingly, by altering the respective roles of the first and second charge units 652, 654 in view of the particular direction of movement of the addressable charge depositing unit 645, the addressable charge depositing unit 645 may generate the appropriate stream of airborne charges to either neutralize charges or build charges to control electrowetting movement of droplets within the microfluidic device as desired.

[00143] FIG. 6B is a diagram 670 including an isometric view schematically representing an example addressable charge depositing unit 675. In some examples, the addressable charge depositing unit 675 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable charge depositing units described in association with at least FIGS. 1A-6A. In some examples, the addressable charge depositing unit 675 comprises a charge building element 684 and a pair of charge neutralizing elements 686A, 686B on opposite sides of the charge building element 684. In some examples, the respective charge building or neutralizing elements 684, 686A, 686B may comprise and/or sometimes be referred to as an ion head, ion-generating head, and the like.

[00144] In some examples, the charge building element 684 may generate airborne charges of a first polarity (e.g. positive) 692 to deposit and build charges 144A on an exterior surface (e.g. 372 in FIG. 3A) of a second plate (e.g. 360 in FIG. 3A) to cause an electric field to control electrowetting movement of droplets within a consumable microfluidic receptacle of a microfluidic device. Flowever, prior to doing so, charges on the second plate (e.g. 360 in FIG. 3A) may be neutralized as desired via operation of the first or second charge neutralizing element 686A, 686B, depending on the direction of movement of the addressable charge depositing unit 675. For instance, upon moving in the first direction M, the first charge neutralizing unit 686A may emit charges 693A to neutralize charges on the second plate (e.g. 360) and first plate (e.g. 110). In some examples, as shown in FIG. 6B, the charges 693A may comprise charges of both a first and second polarity (e.g. positive and negative) within an AC signal. The combination of opposite charges may more effectively neutralize any charges on the second plate (e.g. 360) and/or the first plate (e.g. 110). However, in some examples, the first charge neutralizing element 686A may emit airborne charges of a single polarity (e.g. negative) which are opposite the polarity (e.g. positive) of the charges 692 emitted by the charge building element 684.

[00145] Alternatively, upon moving the addressable charge depositing unit 675 in the opposite second direction N, the second charge neutralizing element 686B may emit charges 693B to deposit charges in order to neutralize residual charges on the second plate (e.g. 360) and first plate (e.g. 110). In some examples, as shown in FIG. 6B, the charges 693B may comprise charges of both a first and second polarity (e.g. positive and negative) within an AC signal. The combination of opposite charges may effectively neutralize any charges on the second plate (e.g. 360) and/or the first plate (e.g. 110). However, in some examples, the second charge neutralizing element 686B may emit airborne charges of a single polarity (e.g. negative) which are opposite the polarity (e.g. positive) of the charges 692 emitted by the charge building element 684.

[00146] Accordingly, the addressable charge depositing unit 675 of FIG. 6B is equipped for efficient, effective charge neutralization and/or charge building regardless of the particular direction (e.g. M or N) of movement of the charge depositing unit 675 to control electrowetting movement of droplets within a microfluidic device.

[00147] In some examples, even when a DC current is used to apply the charges, the charge neutralizing elements in arrangement in FIG. 6B (by which different polarity of charges is applied) may help prevent charge buildup or charge traps in the hydrophobic layer and dielectric layers, which may enhance performance because such charge buildup in a dielectric layer/insulator may otherwise be difficult to remove. [00148] FIG. 6C is a diagram including a side view schematically representing an example two-dimensional addressable charge depositing unit 715 in charging relation to a second plate 720 of a consumable microfluidic receptacle (e.g. 52 in FIGS. 1A-1 C, 102 in FIG. 2A, 302 in FIG. 3A, etc.). In some examples, the addressable charge depositing unit 715 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable charge depositing units described in association with at least FIGS. 1A-4. Meanwhile, the second plate 720 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the consumable microfluidic receptacle 102, 302, 402 described in association with at least FIGS. 1A-4. [00149] As shown in FIG. 6C, addressable charge depositing unit 715 comprises a two dimensional array 741 of addressable charge depositing elements as represented by the arrows 742. The array 741 comprises a size and a shape to cause electrowetting movement of droplets 130 to any one target position (e.g. 217 in FIG. 2B) of a corresponding array 718 of target droplet positions (e.g. 217 in FIG. 2B) of the consumable microfluidic receptacle 720. In some examples, each addressable charge depositing element 742 may correspond to an addressable charge depositing unit 600 in FIG. 5, which may be operated to generate airborne charges (of a desired first polarity or opposite second polarity) in order to deposit and build charges on an exterior surface 722 of second plate 720 (of a consumable microfluidic receptacle) to cause a desired direction of movement of a droplet along a passageway (e.g. 219A-219E in FIG. 2B) within the consumable microfluidic receptacle. In some such examples, any one of the addressable charge depositing elements 742 also may be operated in a charge neutralizing mode, to emit single polarity charges (e.g. negative), or to emit charges of both a first and second polarity (e.g. negative, positive) via an AC signal in a manner similar to the first and second charge neutralizing units 686A, 686B shown in FIG. 6B, in some examples.

[00150] Via the two-dimensional arrangement shown in FIG. 6C, both the second plate 720 of the microfluidic device and the addressable charge depositing unit 715 remain stationary while the array 741 of addressable charge depositing elements 742 may be selectively operated (e.g. individually controllable) to control electrowetting movement for any or all of the target positions (e.g. 217 in FIG. 2B) of the second plate 720 of the consumable microfluidic receptacle (e.g. 52 in FIGS. 1A-1 C, 102 in FIG. 2A, 302 in FIG. 3A, 402 in FIG. 4).

[00151] In some examples, the arrangement described in FIGS. 7A-7B may comprise one example by which the two-dimensional array 741 of FIG. 6C (including addressable charge depositing elements 742) may be implemented. [00152] FIG. 7A is a diagram 800 schematically illustrating an example addressable charge depositing unit 820. In some examples, the addressable charge depositing unit 820 may comprise at least some of substantially the same features and attributes as, the addressable charge depositing units described in association with at least FIGS. 1A-6C. In some examples, the addressable charge depositing unit 820 may comprise one example implementation of at least a portion of the two-dimensional array of the addressable charge depositing unit in FIG. 6C.

[00153] Addressable charge depositing unit 820 includes a corona generating device 822 to generate charges 826 and an electrode grid array 824. The term “charges” as used herein refers to ions (+/-) or free electrons, and in Figure 7 the corona generating device 822 generates charges 826, which may be positive (as shown) or negative, as desired. Electrode array 824 is held in spaced apart relation to device 822 by a distance D13. In one example, device 822 is a corona generating device, such as a thin wire that is less than 100 micrometers in diameter and operating above its corona generating potential. In some examples, while not shown in Figure 7A, device 822 generates negative charges that move under existing electrical fields.

[00154] In some examples, electrode array 824 includes a dielectric film 828, a first electrode layer 830, and a second electrode layer 832. Dielectric film 828 has a first side 834 and a second side 836 that is opposite first side 834. Dielectric film 828 has holes or nozzles 838A and 838B that extend through dielectric film 828 from first side 834 to second side 836. In one example, each of the holes 838A and 838B is individually addressable to control the flow of electrons through each of the holes 838A and 838B separately. Accordingly, any one of the holes 838A, 838B or multiple holes 838A, 838B may be closed or opened, as desired. [00155] First electrode layer 830 is on first side 834 of dielectric film 828 and second electrode layer 832 is on second side 836 of dielectric film 828. First electrode layer 830 is formed around the circumferences of holes 838A and 838B to surround holes 838A and 838B on first side 834. Second electrode layer 832 is formed into separate electrodes 832A and 832B, where electrode 832A is formed around the circumference of hole 838A to surround hole 838A on second side 836 and electrode 832B is formed around the circumference of hole 838B to surround hole 838B on second side 836. Via this juxtaposition with the electrodes, the holes 838A, 838B may sometimes be referred to as electrode nozzles or electrode holes.

[00156] In operation, an electrical potential between first electrode layer 830 and second electrode layer 832 controls the flow of charges 826 from device 822 through holes 838A, 838B in dielectric film 828. In one example, electrode 832A is at a higher electrical potential than first electrode layer 830 and the charges 826 (e.g. positive) are prevented or blocked from flowing through hole 838A. In one example, electrode 832B is at a lower electrical potential than first electrode layer 830 and the charges 826 flow through hole 838B and outwardly to be directed in an airborne manner onto a second plate (e.g. 120, 160, etc.) of a consumable microfluidic receptacle.

[00157] Because FIG. 7A presents an end view of the charge unit 820, it will be understood that the electrode nozzles 838A, 838B may be representative of a two-dimensional array of multiple electrode nozzles, each of which are individually controllable to selectively emit the airborne charges 826 of a particular selectable polarity (e.g. negative or positive) being generated by element 822. [00158] In some examples, the charge unit 820 may be operated in an alternating current (AC) mode, in which a polarity of the power applied to the charge generating device 822 (e.g. wire) and electrode nozzles (e.g. 838A, 838B) is repeatedly changed at a selectable frequency between positive and negative charges. While FIG. 7A depicts positive charges 826, it will be understood that upon a switch in the polarity, negative charges would be generated by the charge generating device 822 and selectively pass through electrode nozzles 838A, 838B.

[00159] As previously mentioned in association with the application of mechanical vibration forces via the vibration element (e.g. 30 in FIG. 1A, 31 A, 31 B in FIGS. 1 B-1C, etc.), the vibration forces may enhance reduction of the contact line resistance and further increase the droplet velocity which is already increased via application of charges via an AC mode.

[00160] FIG. 7B a diagram including a top view schematically representing an example array 937 of electrode nozzles 938 of an example addressable charge depositing unit 900. The array 937 may comprise one example implementation of an array of electrode nozzles (e.g. 838A, 838B in FIG. 7A) in which the electrode nozzles 938 in FIG. 7B generally correspond to the representative electrode nozzles 838A, 838B in FIG. 7A. Moreover, the example array 937 in FIG. 7B may comprise one example implementation of at least a portion of the two-dimensional array 741 in FIG. 6C in which each addressable charge depositing element 742 may correspond to a respective one of the electrode nozzles 938 in the example array 937 of FIG. 8. Similarly, in some examples the body 936 shown in FIG. 7B may comprise a supporting structure and elements which generally corresponds to the structures (e.g. dielectric film 828, electrode plates, etc.) which form the overall structure of electrode array 824 in FIG. 7A. [00161] FIGS. 8A-8C relate to an example electrode control element 1050, 1150, which comprises one example of a charge applicator to apply charges to a microfluidic receptacle (e.g. 302 in FIG. 3A, 402 in FIG. 4). Accordingly, the electrode control element 1050, 1150 may be used instead of using a charge depositing unit, such as 355 in FIG. 3A, to apply charges to a second plate of a consumable microfluidic receptacle in order to cause migration of charges, a voltage differential, etc. (as previously described in association with FIGS. 1A-4) in order to cause electrowetting movement of a droplet 130. Moreover, it will be further understood that such example electrode control elements 1050, 1150 may be operated in a manner consistent with at least some example arrangements in FIGS. 5-7B by which charges are built and/or neutralized, except with the electrode control element applying charges in a releasable contact manner instead of the airborne manner described in association with FIGS. 5-7B.

[00162] FIG. 8A is a diagram 1000 including a side view schematically representing an example electrode control element 1050. As shown in FIG. 8A, electrode control element 1050 comprises a base 1055 which may comprise an insulative material which houses circuitry (and/or conductive elements connectable to circuitry) for controlling generation and application of charges (e.g. 144A in FIG. 8B) via each of the addressable electrodes 1053. In some examples, the electrode control element 1050 may be implemented in the form of a printed circuit board (PCB) or similar structure.

[00163] In some examples, microfluidic operations to be performed via the consumable microfluidic receptacle (e.g. 52, 102, 302, 402) and an addressable electrode control element (e.g. 1050, 1150 in FIGS. 8A-8C) may be implemented in association with a control portion, such as but not limited to control portion 1500 in FIG. 10 and/or in association with a fluid operations engine 1400 in FIG. 10A. Such operations may also comprise control of the later-described relative movement and/or other later-described operational aspects associated with the receptacle and/or electrode control element 1050, 1150.

[00164] In some examples, as shown in FIG. 8A, each electrode 1053 may comprise a length (X1 ) which may comprise a length expected to be approximately the same size as the droplet 130 to be moved, as shown in FIG. 8B. In view of the example volumes of droplets noted above, the length (X1 ) of each electrode 1053 may comprise between about 50 micrometers to about 5 millimeters, and may comprise a width similar to its length in some examples. In some examples, the length (X1 ) of each electrode 1053 may be commensurate with the length (D2 in FIG. 8B) of a droplet or target position (e.g. T1 , T2) of a droplet within the consumable microfluidic receptacle 302.

[00165] In some examples, the length (D2) of the droplet in passageway 119 (e.g. FIG. 2A, 3A, 8B) may sometimes be referred as a length scale of the droplet, or a length of a target position of a droplet. Meanwhile, the distance (X2) between adjacent electrodes 1053 as shown in FIG. 8A may sometimes be referred to as the length scale of the electrodes 1053. In some examples, the length scale (X2) between electrodes 1053 may comprise about 50 to about 75 micrometers (e.g. 2-3 mils) and also may sometimes be referred to as spacing between electrodes 1053.

[00166] As shown in FIG. 8B, in some examples the addressable electrode control element 1050 may be brought into releasable contact against the exterior surface 372 of the second plate 360 of the example consumable microfluidic receptacle 302. In some such examples, the addressable electrode control element 1050 may be supported by or within a frame (e.g. 133 in FIG. 3A) and the consumable microfluidic receptacle 302 may be releasably supportable by the frame to place the consumable microfluidic receptacle 302 and the addressable electrode contact element 1050 into releasable contact and charging relation to each other. In some examples, exterior surface 372 of second plate 360, and a first surface 1051 (e.g. top surface) of the control element 1050 are each planarized to facilitate establishing robust mechanical and electrical connectivity when brought and maintained in releasable contact together.

[00167] As further shown in FIG. 8B, upon the addressable electrode control element 1050 being brought into releasable contact against the consumable microfluidic receptacle 302, a selected electrode(s) 1053 of the addressable electrode control element 1050 may apply charges directly onto the exterior surface 372 of the second plate 360, which may then be referred to as deposited charges 144A. As further shown in FIG. 8B, the electrode 1053 selected from array 1052 (of electrodes 1053) is aligned with a target position T1 (represented via dashed lines), which is immediately adjacent to the droplet 130 and to which the droplet 130 is to be moved.

[00168] After the charges 144A are deposited at surface 372 of second plate 360 of receptacle, the charges 144A behave in a manner substantially similar to that described in association with at least FIGS. 1A-4 to cause electrowetting movement of droplet 130 within and through passageway 119 of receptacle 302. [00169] In some examples, the addressable electrode control element 1050 also may be used to neutralize charges on second plate 360 so as to prepare the microfluidic receptacle 302 to receive an application of fresh charges from electrode control element in preparation of causing further controlled pulling movement of the droplet 130 to a next target position (e.g. T2).

[00170] It will be further understood that charges (e.g. 144A) applied on the second plate 360 (by the electrode control element 1050) will be significantly discharged or at least be discharged to a level at which their voltage is significantly lower than the voltage to be applied before the next electrowetting- caused pulling movement of the droplet 130 occurs to the next target position T2. [00171] In some examples, both of the addressable electrode control element 1050 and the consumable microfluidic receptacle 302 are stationary during microfluidic operations, with the addressable electrode control element 1050 being arranged in a two-dimensional array to apply charges in any desired target location (e.g. 217 in FIG. 2B) of the microfluidic receptacle in order to perform a particular microfluidic operation or sequence of microfluidic operations. One example implementation of a two-dimensional array of such electrodes is described later in association with at least FIG. 8C.

[00172] Flowever, it will be understood that in some examples, the electrode control element 1050 may be mobile and the consumable microfluidic receptacle 302 may be stationary while performing microfluidic operations, while in some examples, the addressable electrode control element 1050 may be stationary and the consumable microfluidic receptacle 302 is moved relative to the addressable electrode control element 1050 during microfluidic operations. In some examples, a frame (e.g. frame 133 in FIG. 3A) may include portions, mechanisms, etc. which may facilitate relative movement between the consumable microfluidic receptacle 302 and the electrode control element 1050.

[00173] It will be further understood that while FIG. 8B depicts second plate 360 as comprising an anisotropic conductive layer as in FIG. 3A, in some examples the electrode control element 1050 may be brought into releasable contact with other example receptacles, such as into releasably contact with a second plate 460 of receptacle 402 of FIG. 4 to deposit charges 144A at a pad 444A (of an electrode such as 442C) in order to initiate the migration of charges, voltage differential, etc. (as previously described in association with FIGS. 1 A-4) in order to cause electrowetting movement of droplet 130. [00174] FIG. 8C is a diagram including a side view schematically representing an example arrangement 1101 comprising a two-dimensional addressable electrode control element 1150 in charging relation to a second plate 1120 of a consumable microfluidic receptacle 1102. In some examples, the addressable electrode control element 1150 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable electrode control element 1050 described in association with at least FIGS. 8A-8B. Meanwhile, the second plate 1120 (and associated consumable microfluidic receptacle 1102) may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the second plate 120, 320, 420 (and associated consumable microfluidic receptacle 52, 102, 302, 402) described in association with at least FIGS. 1A-1 C, 2A, 3A or 4.

[00175] As shown in FIG. 8C, the example addressable electrode control element 1150 comprises a two dimensional array 1171 of individually controllable (e.g. addressable) electrodes 1172. The array 1171 comprises a size and a shape to cause controlled movement of droplets 130 to any one target position (e.g. 217 in FIG. 2B) of a corresponding array of target droplet positions (e.g. 217 in FIG. 2B) implemented via the second plate 1120 of the consumable microfluidic receptacle 1102. In some examples, at least some of the respective example addressable electrodes 1172 of control element 1150 may correspond to the example electrodes 1053 shown in FIGS. 8A-8B, which may be operated to apply charges (of a desired first polarity or opposite second polarity) in order to deposit charges on an exterior surface 1122 of second plate 1120 (of the consumable microfluidic receptacle 1102) to ultimately cause a desired direction of movement of a droplet along a passageway (e.g. 219A-219E in FIG. 2B) within the consumable microfluidic receptacle 1102. In some such examples, any one of the addressable electrodes 1172 also may be operated in a charge neutralizing mode in which charges are emitted having a polarity (e.g. negative) opposite the polarity of the charges (e.g. positive) used to initiate an electrowetting movement of the liquid droplet 130. [00176] Via the two-dimensional arrangement 1101 shown in FIG. 8C, both the second plate 1120 of the consumable microfluidic receptacle 1102 and the addressable electrode control element 1150 remain stationary while the various respective addressable electrodes 1172 (of array 1171 ) may be selectively operated (e.g. individually controlled) to control droplet movement for any or all of the target positions (e.g. 217 in FIG. 2B) of the second plate 1120 of the consumable microfluidic receptacle 1102.

[00177] FIG. 9 is a diagram including a side view schematically representing an example microfluidic device 1200. In some examples, device 1200 comprises at least some of substantially the same features and attributes as the example devices and components described in association with at least FIGS. 1A-8C, except with example device 1200 including an on-board charge applicator 1261 which is incorporated into the device 1200 with microfluidic receptacle 1202. [00178] In some examples, the receptacle portion 1202 of device 1200 comprises at least some of substantially the same features and attributes as the example receptacles described in association with FIGS. 1A-8C, except with a second portion 1262 of the second plate 1260 omitting an anisotropic layer (e.g. FIGS. 3A, 4) and with the second portion 1262 including the above-noted charge applicator 1261 .

[00179] With this in mind, as shown in FIG. 9, in some examples the second portion 1262 of second plate 1260 may comprise a dielectric substrate 1265 supporting a charge applicator 1261 which comprises an array 1282 of electrodes 1263. The electrodes 1263 may comprise actively controlled electrodes 1263 in electrical connection with (or connectable to) circuitry and power to produce selectively charges at, and via, electrodes 1263 in order to deposit charges 144B at a desired location at an interface 1235 (like 135 in FIG. 2A) between the second portion 1262 and the first portion 170 of the second plate 1260 in order to induce electrowetting movement of droplet 130 within passageway 119 of receptacle 1202. As previously noted, the charge applicator (e.g. including active electrodes 1263) may sometimes be referred to as an on-board charge applicator because it forms part of the microfluidic device including receptacle 1202. [00180] FIG. 10A is a block diagram schematically representing an example fluid operations engine 1400. In some examples, the fluid operations engine 1400 may form part of a control portion 1500, as later described in association with at least FIG. 10B, such as but not limited to comprising at least part of the instructions 1511. In some examples, the fluid operations engine 1400 may be used to implement at least some of the various example devices and/or example methods of the present disclosure as previously described in association with FIGS. 1 A-9 and/or as later described in association with FIGS. 10B-11 . In some examples, the fluid operations engine 1400 (FIG. 10A) and/or control portion 1500 (FIG. 10B) may form part of, and/or be in communication with, a consumable microfluidic receptacle, vibration element, charge applicator, etc. such as the devices and methods described in association with at least FIGS. 1 A-9.

[00181] As shown in FIG. 10A, in some examples the fluid operations engine 1400 may comprise a moving function 1402, a merging function 1404, and/or a splitting function 1406, which may track and/or control electrowetting-caused manipulation of droplets within a microfluidic device, such as moving, merging, and/or splitting, respectively.

[00182] In some examples, the fluid operations engine 1400 may comprise a charge control engine 1420 to track and/or control parameters associated with operation of an addressable charge depositing unit to build charges (parameter 1422) or neutralize charges (parameter 1424) on a consumable microfluidic receptacle (of a microfluidic device), as well as to track and/or control the polarity (parameter 1424) of such charges. In some examples, a positioning parameter (1426) of the charge control engine 1220 is to track and/or control positioning (1426) of a charge applicator and a consumable microfluidic receptacle relative to each other to implement such building or neutralizing of charges. In some examples, these parameters 1422, 1424, 1426 may be implemented according to at least some of the example implementations described in association with at least FIGS. 1A-8C and 10B-10.

[00183] In some examples, the fluid operations engine 1400 may comprise a vibration control engine 1440 to apply mechanical vibration acceleration forces on a droplet within a consumable microfluidic receptacle. In some such examples, the applied forces may enhance a velocity of droplet movement, as well as enhance velocity uniformity, precision in starting and/or terminating an instance of droplet movement within the microfluidic receptacle.

[00184] In some examples, a vibration control parameter (implemented via engine 1440) comprises at least some of substantially the same features and attributes by which mechanical vibration acceleration forces are described in association with at least FIGS. 1A-8 and/or 10B-11. With this in mind, in some examples the vibration control engine 1440 may control or manage application of mechanical vibration acceleration forces according to parameters regarding a frequency (1442), an amplitude (1444), a material (1446), power (1448), a time period (1450), a force (1452), and/or a resonance frequency (1460). In some examples, parameters regarding frequency (1442), power (1448), and amplitude (1444) may depend on the other parameters regarding performance, type of microfluidic operations, or other factors such as but not limited to a resonance frequency (1460) of the microfluidic receptacle, which may be related to the type, mass, stiffness of the various materials (1446) and components from the receptacle is constructed.

[00185] In some examples, the force parameter 1452 enables control over a selectable acceleration force to be applied to a droplet (at least during electrowetting movement), and in some examples, one may select a desired value (e.g. amplitude) of such forces with the vibration control engine 1440 automatically adjusting other parameters (e.g. frequency, amplitude, etc.) to achieve the selected force while accounting for other parameters, such as resonance frequency (1460) of the receptacle, power (1448), etc.

[00186] It will be understood that various functions and parameters of fluid operations engine 1400 may be operated interdependently and/or in coordination with each other, in at least some examples.

[00187] FIG. 10B is a block diagram schematically representing an example control portion 1500. In some examples, control portion 1300 provides one example implementation of a control portion forming a part of, implementing, and/or generally managing the example microfluidic devices, as well as the particular portions, components, charge applicators, vibration elements, consumable microfluidic receptacles, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1 A-10A and 10C-11. In some examples, control portion 1500 includes a controller 1502 and a memory 1510. In general terms, controller 1502 of control portion 1500 comprises at least one processor 1504 and associated memories. The controller 1502 is electrically couplable to, and in communication with, memory 1510 to generate control signals to direct operation of at least some of the example portions, components, etc. charge applicators, vibration elements, consumable microfluidic receptacles, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure. In some examples, these generated control signals include, but are not limited to, employing instructions 1511 stored in memory 1510 to at least direct and manage microfluidic operations via electrowetting movement in the manner described in at least some examples of the present disclosure, including applying a mechanical vibration to a droplet at least during electrowetting movement. In some instances, the controller 1502 or control portion 1500 may sometimes be referred to as being programmed to perform the above-identified actions, functions, etc.

[00188] In response to or based upon commands received via a user interface (e.g. user interface 1520 in FIG. 10C) and/or via machine readable instructions, controller 1502 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 1502 is embodied in a general purpose computing device while in some examples, controller 1502 is incorporated into or associated with at least some of the example microfluidic devices, as well as the particular portions, components, charge applicators, vibration elements, consumable microfluidic receptacles, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, etc. as described throughout examples of the present disclosure.

[00189] For purposes of this application, in reference to the controller 1502, the term “processor” shall mean a presently developed or future developed processor (or processing resources) that executes machine readable instructions contained in a memory or that includes circuitry to perform computations. In some examples, execution of the machine readable instructions, such as those provided via memory 1510 of control portion 1500 cause the processor to perform the above-identified actions, such as operating controller 1502 to implement microfluidic operations, including causing electrowetting movement of droplets and/or applying mechanical vibration at least during such electrowetting movement, via the various example implementations as generally described in (or consistent with) at least some examples of the present disclosure. The machine readable instructions may be loaded in a random access memory (RAM) for execution by the processor from their stored location in a read only memory (ROM), a mass storage device, or some other persistent storage (e.g., non- transitory tangible medium or non-volatile tangible medium), as represented by memory 1510. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory 1510 comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller 1502. In some examples, the computer readable tangible medium may sometimes be referred to as, and/or comprise at least a portion of, a computer program product. In other examples, hard wired circuitry may be used in place of or in combination with machine readable instructions to implement the functions described. For example, controller 1502 may be embodied as part of at least one application-specific integrated circuit (ASIC), at least one field- programmable gate array (FPGA), and/or the like. In at least some examples, the controller 1502 is not limited to any specific combination of hardware circuitry and machine readable instructions, nor limited to any particular source for the machine readable instructions executed by the controller 1502.

[00190] In some examples, control portion 1500 may be entirely implemented within or by a stand-alone device.

[00191] In some examples, the control portion 1500 may be partially implemented in one of the example microfluidic operation devices (e.g. charge applicators, vibration elements, and/or consumable microfluidic receptacle) and partially implemented in a computing resource separate from, and independent of, the example microfluidic operation devices (e.g. charge applicators, vibration elements, and/or consumable microfluidic receptacle) but in communication with the example microfluidic operation devices. For instance, in some examples control portion 1500 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 1500 may be distributed or apportioned among multiple devices or resources such as among a server, a microfluidic operation device (e.g. charge applicator, vibration element, and/or consumable microfluidic receptacle), and/or a user interface. [00192] In some examples, control portion 1500 includes, and/or is in communication with, a user interface 1520 as shown in FIG. 10C. In some examples, user interface 1520 comprises a user interface or other display that provides for the simultaneous display, activation, and/or operation of at least some of the example microfluidic devices, as well as the particular portions, components, charge applicators, consumable microfluidic receptacles, substrates, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, etc., as described in association with FIGS. 1A-10B and 11. In some examples, at least some portions or aspects of the user interface 1520 are provided via a graphical user interface (GUI), and may comprise a display 1524 and input 1522.

[00193] FIG. 11 is a flow diagram of an example method 1600. In some examples, method 1600 may be performed via at least some of the devices, components, example microfluidic devices, charge applicators, vibration elements, consumable microfluidic receptacles, microfluidic operations, instructions, control portions, engines, functions, parameters, and/or methods, etc. as previously described in association with at least FIGS. 1A-10C. In some examples, method 1600 may be performed via at least some devices, components, microfluidic devices, charge applicators, vibration elements, consumable microfluidic receptacles, substrates, microfluidic operations, instructions, control portions, engines, functions, parameters, and/or methods, etc. other than those previously described in association with at least FIGS. 1 A- 10C. [00194] As shown at 1612 in FIG. 11 , in some examples method 1600 comprises receiving a microfluidic droplet between a first plate and a second plate of a replaceable microfluidic receptacle. As further shown at 1614 in FIG. 11 , in some examples method 1600 comprises applying charges via the second plate to cause an electric field between the second plate and the first plate, to control electrowetting movement of the microfluidic droplet between the respective first and second plates. As further shown at 1616 in FIG. 11 , method 1600 may comprise reducing a contact line resistance of the droplet via applying mechanical vibration to at least a portion of the receptacle to exert at least about 50 g’s of mechanical acceleration force on the droplet at least during the electrowetting movement. It will be understood that in some examples, the quantitative value (e.g. 50 g’s) of the applied mechanical vibration acceleration forces may comprise other values as described in the various examples of the present disclosure, provided that such forces are substantially greater than a gravitational acceleration force.

[00195] Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.

Claims

1 . A digital microfluidic device comprising: a consumable microfluidic receptacle including a grounded first plate and a second plate spaced apart from the first plate, the microfluidic receptacle to receive a polar liquid droplet between the respective first and second plates, wherein the second plate comprises a first portion to receive charges from a charge applicator, to produce an electric field between the second plate and the first plate at a position adjacent the liquid droplet to pull the liquid droplet through the microfluidic receptacle; and a vibration element coupled to a portion of the receptacle to apply a mechanical vibration acceleration force, at least during droplet movement, which is substantially greater than a gravitational acceleration force.

2. The digital microfluidic device of claim 1 , wherein the mechanical vibration acceleration force is at least about 5000 percent greater than the gravitational acceleration force.

3. The device of claim 2, wherein the mechanical vibration element vibrates at a frequency of at least 200 Hz and with an amplitude of at least 20 micrometers.

4. The device of claim 1 , wherein vibration element is coupled to at least one of: an exterior surface of at least one of the first plate and an exterior surface of the second plate to produce the mechanical vibration in a first orientation generally perpendicular to a first plane through which the receptacle extends; or a side portion of at least one of the respective first and second plates to produce the mechanical vibration in a second orientation generally parallel to the first plane through which the receptacle extends.

5. The digital microfluidic device of claim 1 , wherein the second plate comprises the first portion and a second portion, with the second portion secured relative to the first portion and the second portion comprising the charge applicator, which includes an active electrode control array to selectively apply the charges.

6. The digital microfluidic device of claim 1 , wherein the second plate comprises the first portion and a second portion, wherein the first portion is to receive the charges via the second portion, and wherein the second portion of the second plate comprises at least one of: a passive electrode array layer; and an anisotropic conductivity layer.

7. The digital microfluidic device of claim 6, wherein the second portion of the second plate is to receive releasable contact from the charge applicator, which comprises an active electrode control element including a plurality of electrodes alignable with at least one of: the respective electrodes of the passive electrode array layer; and the anisotropic conductivity layer.

8. The digital microfluidic device of claim 6, wherein the second portion of the second plate is to receive the charges as airborne charges from the charge applicator, wherein the charge applicator comprises a non-contact charge depositing unit.

9. A digital microfluidic device comprising: a consumable microfluidic receptacle including a grounded first plate and a second plate spaced apart from the first plate, the microfluidic receptacle to receive a polar liquid droplet between the respective first and second plates, wherein the second plate comprises a first portion; a charge applicator in charging relation to the first portion of the second plate to selectively emit charges of a selectable polarity to cause an electric field between the second plate and the first plate to induce electrowetting movement of a polar liquid droplet within the consumable microfluidic receptacle; and a vibration element positioned in vibrating relation to a portion of the receptacle to apply a mechanical vibration acceleration force on the droplet at least during the droplet movement which is substantially greater than a gravitational acceleration force.

10. The digital microfluidic device of claim 9, wherein the second plate comprises the first portion and a second portion, and comprising at least one of: the second portion of the second plate being secured relative to the first portion and the second portion comprising the charge applicator, which includes an active electrode control array to selectively apply the charges; the first portion of the second plate is to receive the charges via the second portion with the charges being applied from at least one of: a non-contact charge depositing unit spaced apart from the second portion and to emit the charges as airborne charges; and an electrode control element to be in releasable contact with the second portion of the second plate.

11 . The device of claim 9, wherein the substantially greater, mechanical vibration acceleration force is at least about 5000 percent greater than the gravitational acceleration force, wherein the mechanical vibration is applied a first frequency of at least 200 Hz and an amplitude of at least about 20 micrometers.

12. A method comprising: receiving a microfluidic droplet between a first plate and a second plate of a replaceable microfluidic receptacle; applying charges via the second plate to cause an electric field between the second plate and the first plate, to control electrowetting movement of the microfluidic droplet between the respective first and second plates; and reducing a contact line resistance of the droplet via applying mechanical vibration to at least a portion of the receptacle to exert at least about 50 g’s of mechanical acceleration force on the droplet at least during the electrowetting movement.

13. The method of claim 12, comprising at least one of: applying the vibration in a first orientation generally perpendicular to a first plane through which the receptacle extends; or applying the vibration in a second orientation generally parallel to the first plane through which the receptacle extends.

14. The device of claim 1 , wherein the mechanical vibration element vibrates at a frequency of at least 200 Hz and with an amplitude of at least 20 micrometers, wherein the frequency is within about 30 percent greater or 30 percent less than a resonance frequency of the consumable receptacle of the microfluidic device.

15. The method of claim 12, wherein the applying of charges via the second plate comprises at least one of: emitting charges from a non-contact charge depositing unit as airborne charges for reception at the second plate; emitting charges from a first electrode control array in releasable contact with the second plate; or emitting charges from a second electrode control array from within the second plate.