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EP4374963A1 - Appareil d'électromouillage et son procédé de fonctionnement - Google Patents

Appareil d'électromouillage et son procédé de fonctionnement Download PDF

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Publication number
EP4374963A1
EP4374963A1 EP22209197.7A EP22209197A EP4374963A1 EP 4374963 A1 EP4374963 A1 EP 4374963A1 EP 22209197 A EP22209197 A EP 22209197A EP 4374963 A1 EP4374963 A1 EP 4374963A1
Authority
EP
European Patent Office
Prior art keywords
electrowetting
sweat
electrodes
electrode
control circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP22209197.7A
Other languages
German (de)
English (en)
Inventor
Eduard Gerard Marie Pelssers
Emma MOONEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Priority to EP22209197.7A priority Critical patent/EP4374963A1/fr
Publication of EP4374963A1 publication Critical patent/EP4374963A1/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502769—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements
    • B01L3/502784—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics
    • B01L3/502792—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics for moving individual droplets on a plate, e.g. by locally altering surface tension
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/06—Auxiliary integrated devices, integrated components
    • B01L2300/0627—Sensor or part of a sensor is integrated
    • B01L2300/0645—Electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/16—Surface properties and coatings
    • B01L2300/161—Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00—Moving or stopping fluids
    • B01L2400/04—Moving fluids with specific forces or mechanical means
    • B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0415—Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic
    • B01L2400/0427—Electrowetting

Definitions

  • This invention relates to an electrowetting apparatus suitable for transporting sweat droplets.
  • the invention further relates to a method of operating such an electrowetting apparatus, and a related computer program.
  • Non-invasive, semi-continuous and prolonged monitoring of biomarkers that indicate disease/health status and well-being is in demand for monitoring, for example, dehydration, stress, sleep, children's health and in perioperative monitoring.
  • Sweat tear fluid and saliva may all be obtained non-invasively.
  • Sweat is a particularly accessible biofluid, and is a rich source of information relating to the physiology and metabolism of a subject.
  • Some examples of clinically relevant components of sweat are Na + , Cl - and/or K + to monitor dehydration, lactate as an early warning for inflammation (which is relevant to sepsis), glucose for diabetics and neonates, and cortisol in relation to sleep apnea and stress monitoring.
  • Continuous monitoring of high-risk patients, such as those with serious chronic conditions, pre- or post-operative patients, and the elderly, using sweat biomarker monitoring devices can provide higher quality diagnostic information than regular biomarker spot checks as normally done by repeatedly drawing multiple blood samples.
  • Such continuous monitoring may be in a hospital setting or elsewhere.
  • Human sweat alone or as mixture with sebum lipids may be an easily accessible source for biomarker measurements in wearable on-skin devices.
  • cholesterol is an important biomarker associated with elevated risk in development of cardiovascular diseases.
  • Inflammatory markers or cytokines, such as interleukins e.g. TNF-a, IL-6 play an important role in the immune response and detection or disease monitoring of joint damage in rheumatoid and psoriatic arthritis, and bowel disease.
  • biomarkers that can be detected in eccrine/apocrine sweat are: small molecules such as urea, creatinine, cholesterol, triglycerides, steroid hormones (cortisol), glucose, melatonin; peptides and proteins, including cytokines such as IL-1alpha, IL-1beta, IL-6, TNF alpha, IL-8 and TGF-beta IL-6, cysteine proteinases, DNAse I, lysozyme, Zn- ⁇ 2-glycoprotein, cysteine-rich secretory protein-3 and Dermcidin; and large biomarkers such as the Hepatitis C virus.
  • small molecules such as urea, creatinine, cholesterol, triglycerides, steroid hormones (cortisol), glucose, melatonin
  • peptides and proteins including cytokines such as IL-1alpha, IL-1beta, IL-6, TNF alpha, IL-8 and TGF
  • Capture species such as antibodies, aptamers, molecular imprint polymers, etc.
  • Capture species such as antibodies, aptamers, molecular imprint polymers, etc.
  • biomarkers such as lactate and glucose
  • an enzymatic amperometric sensor may be used to detect certain biomarkers via capture species binding specifically to the target biomarker.
  • the amount of sweat produced by persons at ambient temperature with only light exercise or light labor is relatively small as discussed by Taylor in “Regional variations in transepidermal water loss, eccrine sweat gland density, sweat secretion rates and electrolyte composition in resting and exercising humans", Extrem Physiol Med 2013 ; 2:4, and Simmers in “Prolonged and localised sweat stimulation by iontophoretic delivery of the slowly-metabolised cholinergic agent carbachol", Journal of Dermatological Science 89 (2016) 40-51 ".
  • thermal neutral zone which is in the range of about 25°C to 30°C, the core temperature remains very stable and inducing sweat production is not required for cooling down the body. This zone is defined for a naked man at rest. For a person in a resting state wearing clothes, the thermal neutral zone is lower: in the range of about 13°C to 22°C. Hence, when the temperature is in this zone and the person is in a resting state, the sweat production is very low.
  • the average sweat production is about 3.2 nl/min/gland. Due to the elevated temperature above the thermal neutral zone the body requires cooling and indeed the sweat production rate is increased.
  • WO 2021/074010 A1 discloses an apparatus for transporting sweat droplets to a sensor.
  • the apparatus comprises a chamber for filling with sweat.
  • the chamber has an inlet lying adjacent the surface of the skin, which inlet permits sweat to enter and fill the chamber.
  • the chamber has an outlet from which a sweat droplet protrudes once the chamber has been filled.
  • the apparatus further comprises a fluid transport assembly which is designed to enable the sweat droplet protruding from the outlet to become detached from the outlet of the chamber. The sweat droplet is subsequently transported by the fluid transport assembly to the sensor. Once the protruding droplet has been released from the outlet, the outlet is made available for a subsequent sweat droplet to protrude therefrom upon further filling of the chamber.
  • the released sweat droplet is transported via the fluid transport assembly at least as fast as the subsequent sweat droplet protrudes from the outlet such that the respective sweat droplets do not contact each other before reaching the sensor.
  • the apparatus supplies sweat to the sensor in a dropwise manner.
  • Transport of the released sweat droplet may be via electrowetting.
  • an electrowetting apparatus for transporting a sweat droplet
  • the electrowetting apparatus comprising: a plurality of electrodes arranged to define a transportation path along which the sweat droplet is transportable; an electrowetting transport control circuit for charging and discharging the plurality of electrodes connected to the electrowetting transport control circuit in sequence along the transportation path to enable the sweat droplet to be transported along the transportation path; a sensing circuit for providing, via connection of the sensing circuit with at least one electrode of the plurality of electrodes, an electrical signal for indicating droplet presence on the transportation path; and a switch configured to enable switching between said at least one electrode being connected to and disconnected from the electrowetting transport control circuit.
  • the electrowetting apparatus comprises a switch that enables switching between the at least one electrode (whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal) being connected to and disconnected from the electrowetting transport control circuit.
  • the capability to disconnect, e.g. isolate, the at least one electrode from the electrowetting transport control circuit may assist to reduce interference with the electrical signal by noise associated with the electrowetting transport control circuit, thereby enabling discernment of relatively small signal differences corresponding to the presence or absence of a sweat droplet adjacent the at least one electrode.
  • the switch may also enable, in some embodiments, a sweat droplet to be immobilized adjacent to the at least one electrode (whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal) so that the electrical signal can be more reliably indicative of the presence, or otherwise, of a sweat droplet.
  • the switch is configured to enable switching between a first configuration in which said at least one electrode is connected to the electrowetting transport control circuit and is disconnected from the sensing circuit, and a second configuration in which said at least one electrode is connected to the sensing circuit and is disconnected from the electrowetting transport control circuit.
  • This may provide particularly convenient switching operation, since the connection of the at least one electrode (whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal) to and disconnection from the sensing circuit may be respectively accompanied by disconnection from and connection to the electrowetting transport control circuit.
  • the electrical signal is indicative of a capacitance between the at least one electrode and at least one counter electrode spaced apart from the at least one electrode.
  • the transportation path may, for example, be between the at least one electrode and the at least one counter electrode.
  • the capacitance of a capacitor formed by the electrode(s) and the counter electrode(s) may be in the range 1 to 100 pF, such as typically about 2.5 pF.
  • the difference in this typical value is in the order of about 0.5 pF between air and sweat. This is a relatively small value and noise may obscure the difference between air and a sweat droplet being between these electrodes. However, this noise may be decreased by controlling the switch to isolate the electrode(s), whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal, from the electrowetting transport control circuit.
  • hydrophobic region e.g. a hydrophobic coating, that covers each of the plurality of electrodes.
  • the hydrophobic region is contactable by the sweat droplet.
  • the hydrophobic region further serves to enable capacitance measurement because the hydrophobic region assists to electrically isolate the at least one electrode from the at least one counter electrode.
  • One or more layers of dielectric material may be interposed between the plurality of electrodes and the hydrophobic region.
  • Such dielectric material layer(s) may be provided for the primary purpose of facilitating electrowetting transport of the sweat droplet, but may also be beneficial in respect of the above-mentioned capacitance measurement. This is due to the dielectric material(s) contributing to electrical isolation of the at least one electrode from the at least one counter electrode.
  • a further hydrophobic region may be arranged between the counter electrode(s) and the transportation path.
  • the further hydrophobic region may itself provide a degree of electrical isolation, although any deficiency in terms of the electrical isolation provided by the further hydrophobic region may be compensated by the above-described covering of the plurality of electrodes.
  • the electrowetting transport control circuit is configured to implement the charging and discharging of the plurality of electrodes by controlling an electric field between each of the plurality of electrodes and the at least one counter electrode.
  • the counter electrode may be advantageously utilized for both electrowetting transportation and droplet presence detection.
  • the electrowetting apparatus comprises a further switch configured to enable switching between the at least one counter electrode being connected to and disconnected from the electrowetting transport control circuit, e.g. a ground of the electrowetting transport control circuit. This may further assist to reduce interference with the electrical signal by noise associated with the electrowetting transport control circuit.
  • the plurality of electrodes comprises three or more sets of electrodes, with each set having two or more electrodes
  • the electowetting transport control circuit comprises a switching system that includes a switching element for each of the sets of electrodes, with each switching element being switchable to enable charging and discharging of a respective set of electrodes.
  • the electrodes of a given set may be connected to each other, without electrical connections being present between electrodes that respectively belong to different sets.
  • Such sets of electrodes, with the switching element, e.g. relay, for each set may assist to reduce a number of electrical connections between the plurality electrodes and the switching system relative to, for example, a scenario in which each electrode of the plurality of electrodes were to be individually controlled.
  • eight electrodes to four hundred electrodes may be included in each set.
  • the number of electrodes in the plurality of electrodes may be sixteen to four thousand. Five sets of electrodes may result in the number of electrodes in the plurality of electrodes being forty to two thousand.
  • the at least one electrode comprises, and in some embodiments consists of, a single electrode of one of the sets of electrodes. This may assist to mitigate the risk of an electrical signal deriving from one of the electrodes of a given set to which a sweat droplet is adjacent being rendered unmeasurable by electrical signals deriving from the other electrodes of the set to which no sweat droplet is adjacent, noting the relatively small capacitance difference between the sweat droplet and air.
  • each of the electrodes may be connected to ground, except the electrode(s) whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal.
  • a sweat droplet is located adjacent more than one electrode of the set, such that the at least one electrode comprising only a single electrode of the set may assist to avoid signal confusion associated with several sweat droplets being respectively adjacent electrodes of the same set, once again noting that eight electrodes to four hundred electrodes may be included in each set.
  • the sensing circuit comprises a transimpedance amplifier arranged to convert a current in the sensing circuit to a voltage output.
  • the transimpedance amplifier may enable measurement of the electrical current with a relatively low impedance electrical circuit, thereby minimizing pickup of environmental electrical noise.
  • An additional advantage may be that the distance between the electrodes and the transimpedance amplifier can be relatively large, and therefore no electrical amplification may be required to be implemented on a sweat sampling device, e.g. a wearable sweat sampling device. Rather, the electrical amplification may be instead located in a separate acquisition device. This can make product development easier, for instance without having to incorporate electrical amplification in a wearable sweat sampling device, e.g. via an application-specific integrated circuit (ASIC) included in the wearable sweat sampling device, e.g. an on-sweat patch ASIC.
  • ASIC application-specific integrated circuit
  • the transimpedance amplifier comprises a capacitor in parallel with a feedback resistor of the transimpedance amplifier.
  • the feedback resistor in combination with the capacitor may form a first frequency filter, in other words a high-pass filter.
  • a capacitor may, for example have a capacitance in the range of 100 to 1000 pF, such as about 300 pF.
  • the resistance of the feedback resistor may be in the range of 300 to 600 kQ, such as about 470 kQ.
  • the electrowetting apparatus comprises one or more processors configured to control the switch to switch between said at least one of the plurality of electrodes being connected to and disconnected from the electrowetting transport control circuit.
  • the processor(s) may be configured to obtain the electrical signal while said at least one electrode is disconnected from the electrowetting transport control circuit.
  • the one or more processors comprises: a first processor configured to control the switch to switch between said at least one electrode being connected to and disconnected from the electrowetting transport control circuit, and optionally to control the further switch to switch between said at least one counter electrode being connected to and disconnected from the electrowetting transport control circuit; and a second processor configured to obtain the electrical signal while said at least one electrode is disconnected from the electrowetting transport control circuit.
  • the one or more processors is or are configured to obtain the electrical signal from the sensing circuit as an electrical signal as a function of time, and transform the electrical signal as a function of time to an electrical signal as a function of frequency.
  • Such a transform for example Fourier transform, may provide a filter for significant improvement in noise reduction.
  • the Fourier transform may provide a relatively high-quality filter.
  • the output of the transimpedance amplifier in the form of a voltage output as a function of time, may be fed into an algorithm executing the Fourier transform. Such an algorithm may be run on the processor(s).
  • the electrowetting apparatus may include a lock-in amplifier.
  • Such a lock-in amplifier enables selection of a certain frequency that is to be observed, and enables measurement of both the amplitude and the phase shift (with respect to the original AC signal as produced by an alternating current power supply included in the sensing circuit).
  • the measured amplitude corresponds to the resistance
  • the phase shift corresponds to the capacitance.
  • the electrowetting apparatus may enable a measure of a volume of a sweat droplet to be extracted from the electrical signal.
  • the sweat rate may be determinable. Moreover, an electrical signal resulting from a sweat droplet that is partially overlapping with the at least one electrode and the counter electrode may be measured, followed by measurement of an electrical signal resulting from a sweat droplet that fully covers these electrodes, and subsequently measurement of an electrical signal resulting from again the sweat droplet that is partially overlapping with these electrodes during movement of the sweat droplet along the transportation path.
  • the capacitance value during the partial overlap may contain the information on the volume of the droplet.
  • the manner in which the sweat droplets are formed may be designed to obtain sweat droplets of a uniform volume, some variation in volume may nonetheless arise. Moreover, two sweat droplets may merge along the transportation path. Hence part of the present disclosure concerns measurement of the droplet volume.
  • the droplet volume measurement comprises continuously calibrating the measured value for the sweat droplet by measuring the electrical signal when the at least one electrode and the counter electrode are fully covered by a sweat droplet.
  • the latter should be a constant value, however it is known that measurement between two electrowetting electrodes is not fully an ideal capacitor since it also contains a, although high, electrical resistance value (in the order of megaohms) and it is known that there is a drift in this resistance value. Since the isolated electrodes fully covered by a droplet should give the same value, the measurement in the case of the electrodes being partially covered by a droplet may be calibrated.
  • an external capacitor may be provided over the at least one electrode and the counter electrode.
  • the resultant high pass filter may enable measurement on a plateau (the region where the signal is independent of the applied frequency), thereby rendering the measurement independent of drift in the resistance value.
  • the one or more processors may be configured to extract a measure of a volume of a sweat droplet from the electrical signal.
  • the electrowetting transport control circuit comprises a first alternating current power supply that outputs an alternating voltage and the sensing circuit comprises a second alternating current power supply that outputs an alternating voltage.
  • a supply voltage frequency of the first alternating current power supply is different from that of the second alternating current power supply.
  • the supply voltage frequency may be appropriately selected according to the electrowetting transportation functionality of the electrowetting transport control circuit and according to the droplet presence sensing functionality of the sensing circuit.
  • the supply voltage frequency provided by the first alternating current power supply is lower than that provided by the second alternating current power supply.
  • a supply voltage frequency of the first alternating current power supply is in the range of 500 to 1500 Hz, such as about 1000 Hz.
  • a supply voltage frequency of the second alternating current power supply may be in the range of 2000 to 8000 Hz, preferably in the range of 3000 Hz to 7000 Hz, such as about 5000 Hz.
  • a peak-to-peak amplitude voltage provided by the first alternating current power supply is different from that of the second alternating current power supply.
  • the peak-to-peak amplitude voltage may be appropriately selected according to the electrowetting transportation functionality of the electrowetting transport control circuit and according to the droplet presence sensing functionality of the sensing circuit.
  • the peak-to-peak amplitude voltage provided by the first alternating current power supply is higher than that provided by the second alternating current power supply.
  • the first alternating current power supply's peak-to-peak amplitude voltage is in the range of 25 to 100 V, preferably in the range of 70 V to 90 V, such as about 80 V.
  • the second alternating current power supply's peak-to-peak amplitude voltage may be in the range of 1 to 20 V, preferably in the range of 5 to 15 V, such as about 10 V.
  • Such an amplitude voltage of the second alternating current power supply has been found to be low enough to minimize the risk of the sensing circuit causing migration of the sweat droplet whose presence is being detected, whilst high enough to facilitate sensing, e.g. capacitive sensing, of such a sweat droplet.
  • the electrowetting apparatus may include a plurality of transportation paths, with each electrowetting path being defined by a respective plurality of electrodes, for example with a plurality of electrowetting transport control circuits being included in the electrowetting apparatus, and each electrowetting transport control circuit charging and discharging electrodes of one of the pluralities of electrodes connected thereto in sequence along the respective transportation path to enable the sweat droplet to be transported along the respective transportation path.
  • the sensing circuit may provide, via connection of the sensing circuit with an electrode belonging to each of the pluralities of electrodes, an electrical signal for indicating droplet presence on each of the respective transportation paths.
  • Each plurality of electrodes e.g. together with its associated electrowetting transport control circuit, may be regarded as an "electrowetting structure".
  • a single sensing circuit can be used to sense droplet presence on more than one electrowetting structure.
  • electrowetting apparatus including more than one electrowetting structure, such as two, three, four, five, or more electrowetting structures
  • the electrowetting apparatus may be still able to operate in a scenario in which one of the electrowetting structures is rendered inoperable, e.g. as a result of a manufacturing defect, such as a dust particle introduced during manufacture causing a broken electrical line (noting that the surface area in which the electrodes and electrical lines are provided may be relatively large relative to electronic chips, and thus may be slightly more susceptible to dust particle-related manufacturing errors).
  • the electrowetting apparatus may be included in a sweat sampling apparatus comprising one or more chambers each having an inlet that receives sweat from skin.
  • At least part of the sweat sampling apparatus such as the chamber(s) and the electrodes of the electrowetting apparatus may be included in a wearable device, such as a wearable patch.
  • the wearable device comprises an attachment arrangement, such as adhesive and/or fastenings, configured to enable attachment of the at least part of the sweat sampling apparatus to a body part such that said inlet(s) receive sweat from the skin of the body part.
  • an attachment arrangement such as adhesive and/or fastenings
  • a method of operating an electrowetting apparatus having a plurality of electrodes arranged to define a transportation path along which a sweat droplet is transportable, an electrowetting transport control circuit for charging and discharging the plurality of electrodes connected to the electrowetting transport control circuit in sequence along the transportation path to enable transportation of the sweat droplet, a sensing circuit, and a switch, the method comprising: controlling the switch to disconnect at least one electrode of the plurality of electrodes from the electrowetting transport control circuit; and obtaining, while the at least one electrode is disconnected from the electrowetting transport control circuit, an electrical signal from said at least one electrode for indicating droplet presence on the transportation path.
  • the electrowetting apparatus according to any of the embodiments disclosed herein may be operated in the method.
  • the method further comprises controlling the switch to, following said obtaining, connect the at least one electrode to the electrowetting transport control circuit.
  • the migration of droplet(s) along the transportation path can resume.
  • a computer program comprising computer program code which, when executed on one or more processors, causes the one or more processors to perform all of the steps of the method according to any of the embodiments described herein.
  • One or more non-transitory computer readable media may be provided, which non-transitory computer readable media have a computer program stored thereon, with the computer program comprises computer program code which is configured, when the computer program is run on the one or more processors, to cause the one or more processors to implement the method according to any of the embodiments described herein.
  • the processor(s) may be, for example, the processor(s) included in the electrowetting apparatus described herein.
  • embodiments described herein in relation to the electrowetting apparatus may be applicable to the method and computer program, and embodiments described herein in relation the method and computer program may be applicable to the electrowetting apparatus.
  • an electrowetting apparatus suitable for transporting sweat droplets.
  • the electrowetting apparatus comprises a plurality of electrodes arranged to define a transportation path along which the sweat droplets are transportable.
  • An electrowetting transport control circuit charges and discharges the plurality of electrodes in sequence along the transportation path to enable the sweat droplets to be transported along the transportation path.
  • a sensing circuit provides, via connection of the sensing circuit with at least one electrode of the plurality of electrodes, an electrical signal indicative of droplet presence on the transportation path.
  • a switch enables switching between the electrowetting transport control circuit being connected to and disconnected from the at least one electrode whose connection with the sensing circuit enables the sensing circuit to provide the electrical signal.
  • the capability to disconnect such electrode(s) from the electrowetting transport control circuit assists to alleviate noise from the latter interfering with droplet presence detection.
  • the at least one electrode can be reconnected to the electrowetting transport control circuit to enable sweat droplet transportation via the at least one electrode to resume. Further provided is a method of operating such an electrowetting apparatus, and related computer program.
  • FIGs. 1A to 1D schematically depict an electrowetting apparatus 100 according to an example.
  • the electrowetting apparatus 100 includes a plurality of electrodes 102 whose arrangement defines a transportation path 104 along which sweat droplets are transportable.
  • the electrowetting apparatus 100 further comprises an electrowetting transport control circuit 106 that charges and discharges the plurality of electrodes 102 in sequence along the transportation path 104 to enable the sweat droplets to be transported along the transportation path 104.
  • the electrowetting transport control circuit 106 comprises a switching system 108A, 108B, 108C, 108D, 108E configured to enable switching of each of the plurality of electrodes 102 from being connected to a first terminal of a first power supply 110 to being disconnected from the first terminal of the first power supply 110.
  • the switching system 108A, 108B, 108C, 108D, 108E may be configured to enable switching of each of the plurality of electrodes 102 to being connected to ground 112 (and a second terminal of the first power supply 110) when disconnected from the first terminal of the first power supply 110.
  • any suitable type of switching element can be employed for the switching system 108A, 108B, 108C, 108D, 108E.
  • the switching system 108A, 108B, 108C, 108D, 108E comprises a set of relays that are each switchable to enable switching of each of the plurality of electrodes 102 from being connected to the first terminal of the first power supply 110 to being disconnected from the first terminal of the first power supply 110.
  • a resistor 114A, 114B, 114C, 114D, 114E may be provided, for example included in, each of the relays of the switching system 108A, 108B, 108C, 108D, 108E.
  • the resistors 114A, 114B, 114C, 114D, 114E may assist to provide a controlled path for the current of the relay's coil when the relay's switch is opened.
  • the resistor's 114A, 114B, 114C, 114D, 114E conversion of the energy of the coil's magnetic field to heat may permit the relay to switch relatively quickly, which may be particularly beneficial in this electrowetting transport control circuit 106 application.
  • the resistance of the resistors 114A, 114B, 114C, 114D, 114E may be in the range of 300 to 600 kQ, such as about 470 kQ.
  • relay designs can also be contemplated, for instance including a diode to control the path for the current of the relay's coil as an alternative or in addition to the resistor 114A, 114B, 114C, 114D, 114E.
  • FIGs. 1A to ID indicates, in relation to the wiring diagrammatically represented in these Figures, electrical lines not being connected 116, electrical lines being connected 118, and switch/switching element, e.g. relay, positions 120.
  • each of the plurality of electrodes 102 is covered with a hydrophobic region 122 that is contactable by the sweat droplet.
  • the hydrophobic region 122 comprises a chloropolymer and/or a fluoropolymer, for example CYTOP ® or Fluoropel.
  • one or more layers of dielectric material is or are interposed between the plurality of electrodes 102 and the hydrophobic region 122.
  • dielectric layer(s) may, for instance, include a parylene layer and/or a suitable inorganic layer, such as a tantalum pentoxide or silicon nitride layer coated, e.g. sputtered, on the electrodes 102.
  • the tantalum pentoxide or silicon nitride layer may be coated with parylene, and a chloropolymer and/or fluoropolymer hydrophobic layer applied onto the parylene layer.
  • the switching system 108A, 108B, 108C, 108D, 108E shown in FIG. 1A none of the electrodes 102 is charged via connection to the first terminal of the first power supply 110. Moreover, all of the electrodes 102 are discharged owing to the switching system 108A, 108B, 108C, 108D, 108E connecting each of the electrodes 102 to ground 112 in this configuration.
  • the sweat droplet 124 shown on the transportation path 104 is in a static position adjacent the electrode 102 numbered "3" towards the right hand side of the transportation path 104.
  • each of the electrodes 102 numbered "4" is selectively charged via connection to the first terminal of the first power supply 110.
  • the switching element 108D e.g. relay, is actuated to connect the electrodes 102 numbered "4" to the first terminal of the first power supply 110.
  • Charging of the electrode 102 numbered "4" that is proximal to the sweat droplet 124 may lower the contact angle between the sweat droplet 124 and the hydrophobic region 122, and correspondingly cause the sweat droplet 124 to migrate onto a portion of the hydrophobic region 122 adjacent/facing the charged electrode 102 numbered "4", as shown in FIG. 1B .
  • a sweat droplet 124 that is partially in contact with the hydrophobic region 122 may encounter a driving force and counter forces, in the form of viscous drag and contact angle hysteresis, when an electrode 102 is charged proximal to the surface of the hydrophobic region 122 that is being partially contacted by the sweat droplet 124.
  • the driving force may be created by a surface energy gradient arising from charging of the electrode 102 which promotes the motion of the sweat droplet 124, whereas viscous drag and contact angle hysteresis oppose the motion of the sweat droplet 124.
  • the contact angle hysteresis acts as a resistant force to the movement that tries to retain the sweat droplet 124 in its static position.
  • the sweat droplet 124 accelerates under the resultant force of these opposing forces.
  • the sweat droplet 124 may move from being adjacent the electrode numbered "3" in FIG. 1A to being adjacent the electrode numbered "4" in FIG. 1B due to the charging of the latter by the electrowetting transport control circuit 106.
  • the sweat droplet 124 may be caused to migrate to a portion of the hydrophobic region 122 adjacent the successive electrode 102, and so on.
  • This sequence may be regarded as an "electrowetting wave".
  • the electrowetting transport control circuit 106 may be configured, in combination with the plurality of electrodes 102, to provide such an electrowetting wave.
  • an electrowetting apparatus 100 in order to transport/migrate sweat droplets may offer relatively rapid migration and precise control over the transport, e.g. velocities, of the sweat droplets 124.
  • the propagation of the electrowetting wave may, in principle, be applied to transport sweat droplets over relatively long distances.
  • the electrowetting apparatus 100 may include at least one counter electrode 126.
  • the electrowetting transport control circuit 106 may accordingly be configured to implement the charging and discharging of the plurality of electrodes 102 by controlling the electric field between each of the plurality of electrodes 102 and the at least one counter electrode 126.
  • the transportation path 104 may be arranged between the plurality of electrodes 102 and the at least one counter electrode 126.
  • a further hydrophobic region 128 may be arranged between the counter electrode(s) 126 and the transportation path 104.
  • the further hydrophobic region 128 may be formed from any suitable hydrophobic material, such as a chloropolymer and/or a fluoropolymer, for example CYTOP ® and/or Fluoropel, as described above in relation to the hydrophobic region 122.
  • a chloropolymer and/or a fluoropolymer for example CYTOP ® and/or Fluoropel, as described above in relation to the hydrophobic region 122.
  • One or more (further) layers of dielectric material may be interposed between the counter electrode(s) 126 and the further hydrophobic region 128, similarly to the above-described layer(s) of dielectric material that may be present between the plurality of electrodes 102 and the hydrophobic region 122.
  • the at least one counter electrode 126 may be provided/formed in any suitable manner.
  • the at least one counter electrode 126 comprises, e.g. is in the form of, a conductive layer, for example an indium tin oxide layer.
  • the further hydrophobic region 128 may be interposed between the conductive layer and the transportation path 104.
  • the transportation path 104 extends along a channel defined between opposing substrate portions 130, 132.
  • each of the hydrophobic region 122 and the further hydrophobic region 128 may be exposed to a channel provided between a substrate portion 130 and a further substrate portion 132, along which channel at least part of the transportation path 104 extends.
  • the hydrophobic region 122 may be an integral part of the substrate portion 130, provided that the substrate portion 130 is formed from a hydrophobic material.
  • the further hydrophobic region 128 may be an integral part of the further substrate portion 132, provided that the further substrate portion 132 is formed from a hydrophobic material.
  • each of the at least one counter electrode 126 may be connected to ground 112, as shown in FIGs. 1A to 1D .
  • the single counter electrode 126 e.g. conductive layer, shown in FIGs. 1A to ID may represent a relatively straightforward way of implementing the at least one counter electrode 126, although any number of counter electrode(s) 126 can be contemplated.
  • the first power supply 110 comprises, e.g. is defined by, a first alternating current power supply whose peak-to-peak amplitude voltage is in the range of 25 to 100 V, preferably in the range of 70 to 90 V, such as about 80 V.
  • Such a peak-to-peak amplitude voltage may provide a sufficiently strong electric field for implementing the electrowetting transportation of sweat droplets whilst not being so high so as to compromise practical application of the electrowetting apparatus 100, e.g. in a wearable sweat sampling device.
  • a supply voltage frequency of the first alternating current power supply may be in the range of 500 to 1500 Hz, such as about 1000 Hz. Such a supply voltage frequency has been found to provide efficient charging of the electrodes 102, and concomitant effective sweat droplet 124 transportation.
  • the peak-to-peak amplitude voltage of the first alternating current power supply included in, e.g. defining, the first power supply 110 is about 80 V, and the supply voltage frequency of the first alternating current power supply is about 1000 Hz.
  • Charging of each of the electrodes 102 may require less than 10 ms, for example less than 1 ms.
  • the switching system 108A, 108B, 108C, 108D, 108E may be configured such that the sweat droplet 124 migrates, in other words "flips", from one electrode 102 to a successive electrode 102 in 1 to 500 ms, depending on air or oil in the channel 104. Typically, in air less than 10 ms.
  • the plurality of electrodes 102 comprises three or more sets of electrodes 102, with each set having two or more electrodes 102.
  • the switching system 108A, 108B, 108C, 108D, 108E may accordingly include a switching element 108A, 108B, 108C, 108D, 108E, e.g. relay, for each of the sets of electrodes 102, with each switching element 108A, 108B, 108C, 108D, 108E being configured to enable switching of a respective set of electrodes 102 from being connected to the first terminal of the first power supply 110 to being disconnected from the first terminal of the first power supply 110.
  • only the electrodes 102 of a given set may be connected to each other, without electrical connections being present between electrodes 102 that respectively belong to different sets.
  • Such sets of electrodes 102, with the switching element 108A, 108B, 108C, 108D, 108E, e.g. relay, for each set may assist to reduce a number of electrical connections between the plurality electrodes 102 and the switching system 108A, 108B, 108C, 108D, 108E relative to, for example, a scenario in which each electrode 102 of the plurality of electrodes 102 were to be individually controlled.
  • the plurality of electrodes 102 comprises five sets of electrodes 102.
  • the electrodes 102 numbered “1" correspond to a first set of electrodes 102 that is connected to and disconnected from the first terminal of the first power supply 110 via the switching element 108A
  • the electrodes 102 numbered "2" correspond to a second set of electrodes 102 that is connected to and disconnected from the first terminal of the first power supply 110 via the switching element 108B
  • the electrodes 102 numbered "3" correspond to a third set of electrodes 102 that is connected to and disconnected from the first terminal of the first power supply 110 via the switching element 108C
  • the electrodes 102 numbered "4" correspond to a fourth set of electrodes 102 that is connected to and disconnected from the first terminal of the first power supply 110 via the switching element 108D
  • the electrodes 102 numbered "5" correspond to a fifth set of electrodes 102 that is connected to and
  • FIGs. 1A to ID is to provide an illustration of the principle, and any number of sets of electrodes 102 can be contemplated, such as two, three, four, six, seven, eight, nine, ten, and so on.
  • electrodes 102 Whilst four electrodes 102 are included in each of the five sets shown in FIGs. 1A to 1D , this is also only for the purpose of illustration. In some embodiments, eight electrodes 102 to four hundred electrodes 102 may be included in each set, in other words eight electrodes 102 to four hundred electrodes 102 may have the same number: "1", "2", "3", etc.
  • one additional electrical connection to the single counter electrode 126 is provided (in addition to the above-mentioned five electrical connections connecting the five sets of electrodes 102 to the switching system 108A, 108B, 108C, 108D, 108E).
  • the electrowetting apparatus 100 shown in FIGs. 1A to ID comprises a sensing circuit 134 for providing, via connection of the sensing circuit 134 with at least one electrode 136 of the plurality of electrodes 102, an electrical signal indicative of droplet presence on the transportation path 104.
  • sensing circuit 134 Any suitable sensing principle may be employed in order for the sensing circuit 134 to provide the electrical signal indicative of droplet presence on the transportation path 104. Particular mention is made of capacitive droplet sensing.
  • a dielectric value is changed therebetween given that air and moisture, e.g. sweat, have different dielectric values from each other.
  • Such a change in dielectric value is detectable, thereby enabling, for instance, counting of sweat droplets 124, and in certain embodiments determination of the volume of each sweat droplet 124 (as will be explained herein below).
  • even relatively low sweat rates may be measurable.
  • Such capacitive droplet sensing by the sensing circuit 134 may also be particularly suitable in the context of transportation via electrowetting, given the associated electrical isolation of the electrodes 102 from the sweat droplet owing to the hydrophobic region 122 and/or dielectric layer(s) between each of the electrodes 102, 126 and the transportation path 104.
  • the electrical signal is indicative of a capacitance between the at least one electrode 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) and the at least one counter electrode 126 spaced apart from the at least one electrode 136.
  • the sensing circuit 134 may include a second power supply 138.
  • the second power supply 138 comprises, e.g. is defined by, a second alternating current power supply whose peak-to-peak amplitude voltage is in the range of 1 to 20 V, preferably in the range of 5 to 15 V, such as about 10 V.
  • Such a peak-to-peak amplitude voltage has been found to be low enough to minimize the risk of the sensing circuit 134 causing migration of the sweat droplet 124 whose presence is being detected, whilst high enough to facilitate sensing, e.g. capacitive sensing, of such a sweat droplet 124.
  • the peak-to-peak amplitude voltage provided by the first alternating current power supply may be different from that of the second alternating current power supply.
  • the peak-to-peak amplitude voltage may be appropriately selected according to the electrowetting transportation functionality of the electrowetting transport control circuit 106 and according to the droplet presence sensing functionality of the sensing circuit 134.
  • the peak-to-peak amplitude voltage e.g. in the range of 25 to 100 V, provided by the first alternating power supply is higher than that provided by the second alternating power supply, e.g. 1 to 20 V.
  • a supply voltage frequency of the second alternating current power supply may be in the range of 2000 to 8000 Hz, preferably in the range of 3000 to 7000 Hz, such as about 5000 Hz. Such a supply voltage frequency has been found to facilitate capacitive sensing of sweat droplets 124.
  • the peak-to-peak amplitude voltage of the second alternating current power supply included in, e.g. defining, the second power supply 138 is about 10 V, and the supply voltage frequency of the second alternating current power supply is about 5000 Hz.
  • the peak-to-peak amplitude voltage of the first alternating current power supply included in, e.g. defining, the first power supply 110 is about 80 V
  • the supply voltage frequency of the first alternating current power supply is about 1000 Hz
  • the peak-to-peak amplitude voltage of the second alternating current power supply included in, e.g. defining, the second power supply 138 being about 10 V
  • the supply voltage frequency of the second alternating current power supply being about 5000 Hz.
  • the charging of an electrode 102 may require less than 1 ms, and 10 ms may be used for gathering the electrical signal(s).
  • a sweat droplet 124 may migrate to a successive electrode 102 in 1 to 500 ms, depending on air or oil in the channel 104. Typically, in air less than 10 ms.
  • the supply voltage frequency provided by the first alternating current power supply may be different from that of the second alternating current power supply.
  • the supply voltage frequency may be appropriately selected according to the electrowetting transportation functionality of the electrowetting transport control circuit 106 and according to the droplet presence sensing functionality of the sensing circuit 134.
  • the supply voltage frequency e.g. in the range of 500 to 1500 Hz, provided by the first alternating power supply is lower than that provided by the second alternating power supply, e.g. 2000 to 8000 Hz.
  • first and second in the context of the first power supply 110 included in the electrowetting transport control circuit 106 and the second power supply 138 included in the sensing circuit 134 respectively are used to distinguish between the power supplies 110, 138 provided for each of these circuits 106, 134. It is nonetheless noted that in alternative embodiments a single power supply (not visible) could conceivably be employed instead of the first power supply 110 and the second power supply 138 being both included in the electrowetting apparatus 100.
  • a switch 140 is configured to enable switching between the at least one electrode 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) being connected to and disconnected from the electrowetting transport control circuit 106.
  • the capability to disconnect the at least one electrode 136 from the electrowetting transport control circuit 106 may assist to reduce interference with the electrical signal by noise associated with the electrowetting transport control circuit 106, thereby enabling discernment of relatively small signal differences.
  • the capacitance of a capacitor formed by the electrode(s) 136 and the counter electrode(s) 126 may be in the range 1 to 100 pF, such as typically about 2.5 pF.
  • the difference in this typical value is in the order of about 0.5 pF between air and sweat.
  • This is a relatively small value and noise may obscure the difference between air and a sweat droplet 124 being between the electrically isolated electrodes 126, 136.
  • this noise may be decreased by controlling the switch 140 to isolate the electrode(s) 136 from the electrowetting transport control circuit 106.
  • the switch 140 may also enable, in some embodiments, the sweat droplet 124 to be immobilized adjacent the at least one electrode 136 so that the electrical signal can be more reliably indicative of the presence, or otherwise, of a sweat droplet 124.
  • the sweat droplet 124 is adjacent the electrode 102 numbered "4" towards the right hand side of the transportation path 104, which also happens to be the at least one electrode 136 whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal.
  • the position of the switch 140 is such that the electrode(s) 136 is or are still connected to the electrowetting transport control circuit 106.
  • the position of the switch 140 is changed to a position in which the electrode(s) 136 is or are disconnected from the electrowetting transport control circuit 106. This may reduce interference with the electrical signal by noise associated the electrowetting transport control circuit 106, as previously described.
  • the lower peak-to-peak amplitude voltage, e.g. 1 to 20 V, provided by the second alternating current power supply may be sufficiently low to minimize the risk of the sensing circuit 134 causing migration of the sweat droplet 124 still at the position of the neighboring electrode numbered "3" or at the position of the successive electrode numbered "5".
  • the position of the sweat droplet 124 may be maintained until the electrode(s) 136 is or are connected again to the electrowetting transport control circuit 106, at which point the sweat droplet 124 may again migrate along the transportation path 104.
  • the droplet migration shown in FIG. ID is implemented via the switching element 108E, e.g. relay, connecting each of the electrodes 102 numbered "5", in other words each of the electrodes 102 belonging to that set, to the first terminal of the first power supply 110.
  • the switching element 108E e.g. relay
  • the switch 140 is configured to enable switching between a first configuration in which the at least one electrode 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) is connected to the electrowetting transport control circuit 106 and is disconnected from the sensing circuit 134, as shown in FIGs. 1A , 1B and 1D , and a second configuration in which the at least one electrode 136 is connected to the sensing circuit 134 and is disconnected from the electrowetting transport control circuit 106, as shown in FIG. 1C .
  • This may provide particularly convenient switching operation, since the at least one electrode's 136 connection to and disconnection from the sensing circuit 134 may be respectively accompanied, e.g. automatically, by disconnection from and connection to the electrowetting transport control circuit 106.
  • the switch 140 can be implemented in any suitable manner.
  • the switch 140 may comprise a relay.
  • the electrowetting apparatus 100 may include a further switch 142 configured to enable switching between the at least one counter electrode 126 being connected to and disconnected from the electrowetting transport control circuit 106. This may further assist to reduce interference with the electrical signal by noise associated with the electrowetting transport control circuit 106.
  • the further switch 142 can be implemented in any suitable manner.
  • the further switch 142 may comprise a relay.
  • the further switch 142 may be configured to enable switching between a first configuration in which the at least one counter electrode 126 is connected to the electrowetting transport control circuit 106 and is disconnected from the sensing circuit 134, as shown in FIGs. 1A , 1B and 1D , and a second configuration in which the at least one counter electrode 126 is connected to the sensing circuit 134 and is disconnected from the electrowetting transport control circuit 106, as shown in FIG. 1C .
  • the switch 140 is controllable such that the electrode(s) 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) is or are disconnected from the electrowetting transport control circuit 106 while the further switch 142 is controllable such that the counter electrode(s) 126 is or are disconnected from the electrowetting transport control circuit 106.
  • the first configuration of the switch 140 is selectable at the same time as the first configuration of the further switch 142
  • the second configuration of the switch 140 is selectable at the same time as the second configuration of the further switch 142.
  • Such selection of the configurations of the switch 140 and the further switch 142 may be implemented via processor(s) configured to control the switch 140 and the further switch 142, as described herein below with reference to FIG. 3 .
  • the at least one electrode 136 may comprise, or in some embodiments consist of, a single electrode 136 of one of the sets of electrodes 102. This may assist to mitigate the risk of an electrical signal deriving from one of the electrodes 102 of a given set to which a sweat droplet 124 is adjacent being rendered unmeasurable by electrical signals deriving from the other electrodes 102 of the set to which no sweat droplet 124 is adjacent, noting the relatively small capacitance difference between the sweat droplet 124 and air.
  • a sweat droplet 124 is located adjacent more than one electrode 102 of the set, such that the at least one electrode 136 comprising only a single electrode 136 of the set may assist to avoid signal confusion associated with several sweat droplets 124 being respectively adjacent electrodes 102 of the same set, once again noting that eight electrodes 102 to four hundred electrodes 102 may be included in each set.
  • the sensing circuit 134 comprises a transimpedance amplifier 144 arranged to convert a current in the sensing circuit 134 to a voltage output, V out .
  • the transimpedance amplifier 144 may enable measurement of the electrical current with a relatively low impedance electrical circuit (due to the above-mentioned relatively large resistor being obviated), thereby minimizing pickup of environmental electrical noise.
  • An additional advantage may be that the distance between the electrodes 102 and the transimpedance amplifier 144 can be relatively large, and therefore no electrical amplification may be required to be implemented on a sweat sampling device, e.g. a wearable sweat sampling device. Rather, the electrical amplification may be instead located in a separate acquisition device. This can make product development easier, for instance without having to incorporate electrical amplification in a wearable sweat sampling device, e.g. via an application-specific integrated circuit (ASIC) included in the wearable sweat sampling device, e.g. an on-sweat patch ASIC.
  • ASIC application-specific integrated circuit
  • the V out of the transimpedance amplifier 144 may be proportional to a value of the alternating current present between the electrode(s) 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) and the counter electrode(s) 126.
  • the sensing circuit 134 e.g. the transimpedance amplifier 144 included in the sensing circuit 134, includes an operational amplifier 146. It is noted that the power supply lines to the operational amplifier 146 depicted in FIGs. 1A to 1D and 2 have not been drawn.
  • operational amplifier 146 Any suitable type of operational amplifier 146 can be contemplated. Particular mention is made of an operational amplifier 146 with a low input bias current. A non-limiting example of the latter is a TL072CP operational amplifier from Texas Instruments.
  • the transimpedance amplifier 144 comprises a capacitor 148 in parallel with a feedback resistor 150 of the transimpedance amplifier 144.
  • the feedback resistor 150 in combination with the capacitor 148 may form a first frequency filter.
  • Such a capacitor 148 may, for example have a capacitance in the range of 100 to 1000 pF, such as about 300 pF.
  • the resistance of the feedback resistor 150 may be in the range of 300 to 600 kQ, such as about 470 kQ.
  • the resistance of all of the resistors 114A, 114B, 114C, 114D, 114E and the feedback resistor 150 may be in the range of 300 to 600 kQ, such as about 470 kQ.
  • the electrowetting apparatus 100 comprises one or more processors 152 configured to control the switch 140 to switch between the at least one of the plurality of electrodes 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) being connected to and disconnected from the electrowetting transport control circuit 106.
  • Control signal(s) for controlling the switch 140 is or are schematically represented in FIG. 3 by the arrow extending from the block denoting the processor(s) 152 to the block denoting the switch 140.
  • the one or more processors 152 is or are configured to control the further switch 142 to switch between the at least one counter electrode 126 being connected to and disconnected from the electrowetting transport control circuit 106.
  • Control signal(s) for controlling the further switch 142 is or are schematically represented in FIG. 3 by the arrow extending from the block denoting the processor(s) 152 to the block denoting the further switch 142.
  • the processor(s) 152 may be configured to obtain the electrical signal while the at least one electrode 136 (whose connection with the sensing circuit 134 enables the sensing circuit 134 to provide the electrical signal) is disconnected from the electrowetting transport control circuit 106.
  • the electrical signal being obtained by the processor(s) 152 is schematically represented in FIG. 3 by the arrow extending from the block denoting the sensing circuit 134 to the block denoting the processor(s) 152.
  • the one or more processors 152 comprises: a first processor configured to control the switch 140 to switch between said at least one electrode 136 being connected to and disconnected from the electrowetting transport control circuit 106, and optionally to control the further switch 142 to switch between said at least one counter electrode 126 being connected to and disconnected from the electrowetting transport control circuit 106; and a second processor configured to obtain the electrical signal while said at least one electrode 136 is disconnected from the electrowetting transport control circuit 106.
  • the first processor may also control the switching system 108A, 108B, 108C, 108D, 108E.
  • the one or more processors 152 is or are configured to obtain the electrical signal from the sensing circuit 134 as an electrical signal as a function of time, and transform the electrical signal as a function of time to an electrical signal as a function of frequency.
  • Such a transform for example Fourier transform, may provide a filter for significant improvement in noise reduction.
  • the Fourier transform may provide a relatively high-quality filter.
  • the V out of the transimpedance amplifier 144 in the form of a voltage output as a function of time, may be fed into an algorithm executing the Fourier transform.
  • Such an algorithm may be run on the processor(s) 152, e.g. on a processor included in a computer that receives the raw data in a digitized format from an analogue to digital converter.
  • the electrowetting apparatus 100 may include a lock-in amplifier (not visible in the Figures).
  • Such a lock-in amplifier enables selection of a certain frequency that is to be observed, and enables measurement of both the amplitude and the phase shift (with respect to the original AC signal as produced by the AC source, in other words the second alternating current power supply).
  • the measured amplitude corresponds to the resistance
  • the phase shift corresponds to the capacitance.
  • the electrowetting apparatus 100 may enable a measure of a volume of a sweat droplet 124 to be extracted from the electrical signal.
  • the sweat rate in the channel between the substrate portion 130 and the further substrate portion 132 may be determinable. Moreover, an electrical signal resulting from a sweat droplet 124 that is partially overlapping with the isolated electrodes 126, 136 may be measured, followed by measurement of an electrical signal resulting from a sweat droplet 124 that fully covers the isolated electrodes 126, 136, and subsequently measurement of an electrical signal resulting from again the sweat droplet 124 that is partially overlapping with the isolated electrodes 126, 136 during movement of the sweat droplet 124 along the transportation path 104.
  • the capacitance value during the partial overlap may contain the information on the volume of the droplet 124.
  • the manner in which the sweat droplets 124 are formed may be designed to obtain sweat droplets 124 of a uniform volume, some variation in volume may nonetheless arise. Moreover, two sweat droplets 124 may merge along the transportation path 104. Hence part of the present disclosure concerns measurement of the droplet volume.
  • the droplet volume measurement comprises continuously calibrating the measured value for the sweat droplet 124 with the electrodes 126, 136 by measuring electrical signal when the isolated electrodes 126, 136 are fully covered by a sweat droplet 124.
  • the latter should be a constant value, however it is known that measurement between two electrowetting electrodes 126, 136 is not fully an ideal capacitor since it also contains a, although high, electrical resistance value (in the order of megaohms) and it is known that there is a drift in this resistance value. Since the isolated electrodes 126, 136 fully covered by a droplet 124 should give the same value, the measurement in the case of the isolated electrodes 126, 136 being partially covered by a droplet 124 may be calibrated.
  • an external capacitor may be provided over the two electrodes 126, 136.
  • the resultant high pass filter may enable measurement on the plateau (the region where the signal is independent of the applied frequency), thereby rendering the measurement independent of drift in the resistance value.
  • the one or more processors 152 may be configured to extract a measure of a volume of a sweat droplet 124 from the electrical signal.
  • FIG. 4 schematically depicts, in cross-sectional view, part of a sweat sampling apparatus 200 according to an example.
  • the sweat sampling apparatus 200 may include the electrowetting apparatus 100 according to any of the embodiments described herein.
  • the sweat sampling apparatus 200 comprises a chamber 202 having an inlet 204.
  • the inlet 204 receives sweat from the skin 206.
  • the inlet 204 may be disposed adjacent to a surface of the skin 206. Whilst a single chamber 202 is depicted in FIG. 4 , this is not intended to be limiting, and in other examples a plurality of chambers 202 may be included in the sweat sampling apparatus 200, as will be further described herein below.
  • the inlet 204 is shown proximal to a sweat gland 208.
  • the sweat excreted by the sweat gland 208 enters and fills the chamber 202 via the inlet 204.
  • the sweat sampling apparatus 200 may comprise a substrate 210 which is attached to the surface of the skin 206.
  • a lower surface of the substrate 210 is in direct contact with the surface of the skin 206.
  • the chamber 202 takes the form of an aperture delimited by the substrate 210.
  • the substrate 210 may be formed of any suitable material, e.g. a polymer, capable of being disposed on the skin.
  • the substrate 210 may have at least a degree of flexibility so as to enable conformal application to the surface of the skin 206. More rigid substrates 210 may also be contemplated, providing the inlet 204 can receive sweat from the skin 206.
  • the further substrate portion 132 described above in relation to the electrowetting apparatus 100 may be included in the substrate 210.
  • the substrate 210 may, for instance, be adhered to the surface of the skin 206 using a suitable biocompatible adhesive.
  • the substrate 210 may be held against the surface of the skin 206 by fastenings, e.g. straps, for attaching the substrate 210 to the body of the subject.
  • each inlet 204 of the plurality of chambers 202 is dimensioned to receive sweat from, on average, 0.1 to 1 active sweat glands. This may assist the sweat sampling apparatus 200 to be used for determination of the sweat rate per sweat gland.
  • the diameter of the inlet 204 for receiving sweat from the skin 206 is selected to be relatively small, for example 200-2000 ⁇ m, such as 300-1200 ⁇ m, e.g. about 360 ⁇ m or about 1130 ⁇ m.
  • the diameter of sweat gland outlets on the surface of the skin 206 are typically in the range of about 60 ⁇ m to 120 ⁇ m.
  • a relatively small inlet 204 may assist to reduce the chances of two or more sweat glands 208 excreting into the same inlet 204, which can complicate interpretation of the electrical signals.
  • the apparatus 200 may, for instance, include a plurality of such chambers 202, for example 2 to 50 chambers 202, such as 10 to 40 chambers 202, e.g. about 25 chambers 202.
  • a sweat droplet 124 protrudes from an outlet 214 of the chamber 202.
  • the outlet 214 is delimited by an upper surface of the substrate 210, and a hemispherical sweat droplet 124 forms on top of the outlet 214 once the chamber 202 has been filled with sweat.
  • the sweat sampling apparatus 200 may be configured such that the speed of formation of the sweat droplet 124 is determined by the sweat rate, while the volume of the sweat droplet 124 is determined by the electrowetting apparatus 100. This will be explained in further detail herein below.
  • the respective areas of the inlet 204 and the outlet 214 may be selected to ensure efficient filling of the chamber 202 and sweat droplet 124 formation over a range of sweat rates.
  • Each inlet 204 may, for example, have an area between 0.005 mm 2 to 20 mm 2 .
  • the inlet 204 and the outlet 214 have selected fixed dimensions for this purpose.
  • the apparatus 200 may be configurable such that at least some of the dimensions and geometry relevant to sweat droplet 124 formation can be varied.
  • the chamber 202 is dimensioned to fill up with sweat within 10-15 minutes.
  • the formation of the hemispherical sweat droplet 124 following filling of the chamber 202 preferably occurs typically within 10 seconds at relatively low sweat rate, e.g. 0.2 nl/min/gland.
  • the diameter of the outlet 214 may, for example, be in the range of 10 ⁇ m to 100 ⁇ m, e.g. 15 ⁇ m to 60 ⁇ m, such as about 33 ⁇ m, in order to assist in controlling the sweat droplet 124 size so that its volume is uniform and reproducible.
  • the outlet 214 having such a diameter, e.g. about 33 ⁇ m several sweat droplets 124 may be formed during a single sweat burst (typically lasting 30 seconds) of a sweat gland 208, even with sweat rates as low as 0.2 nl/min/gland. Consequently, sufficient sweat droplets 124 may be generated and transported by the sweat sampling apparatus 200 in order for the sweat rate to be reliably estimated.
  • the length 216 (denoted by the double-headed arrow) is about 500 ⁇ m.
  • the dimensions of the chamber 202, inlet 204, and outlet 214 may be selected according to, for instance, the sweat rate of the subject.
  • the volume of the chamber 202 may be minimized in order to decrease the filling time. This may assist to ensure a minimal delay between actual sweat excretion and sensing/monitoring of the sweat droplets 124.
  • the volume of the chamber 202 may be in the range of 0.1-100 nl, such as 0.5-50 nl, e.g. 1-20 nl.
  • the volume of the chamber 202 may be minimized in various ways in order to minimize the time required to fill the chamber 202 with sweat. Such modifications may be, for instance, to the substrate 210 delimiting the chamber 202.
  • FIG. 4 shows an example in which the chamber 202 tapers from the inlet 204 towards the outlet 214.
  • the volume of such a tapering chamber 202 will be less than, for example, a cylindrical chamber 202 having the same height and base diameter dimensions.
  • the length dimension 216 of the substrate 210 shown in FIG. 4 is about 500 ⁇ m
  • the filling time of this tapering chamber 202 may be about 10 minutes and the sweat droplet 124 formation may take around 12 seconds.
  • filling of a cylindrical chamber 202 having the same height (50 ⁇ m) and base (360 ⁇ m) dimensions may take around 50 minutes, and the formation time of the hemispherical sweat droplet 124 may be more than 3 hours.
  • sweat glands 208 tend to excrete in sweat bursts, each sweat burst being followed by a rest period in which the glands 208 are not excreting.
  • the sweat rate may be about six times larger than the average sweat rate. The reason is that in a time window of 180 seconds there is typically a sweat burst of 30 seconds and a rest period of typically 150 seconds, hence there is a factor of six between the average sweat rate and the sweat rate during a sweat burst.
  • the time to form the depicted sweat droplet 124 is about 12 seconds during the sweat burst of the sweat gland 208.
  • chamber 202 may be partitioned into compartments, with at least some of the compartments being fluidly connected to each other in order to permit the chamber 202 to be filled with sweat.
  • compartments may be formed by pillars.
  • Such pillars may form part of the substate 210, and in such an example may be formed by patterning, e.g. etching, the lower surface of the substrate 210. Other suitable ways of forming such pillars will be readily apparent to the skilled person.
  • a porous material e.g. a frit-like material, such as a sintered glass material, may partition the chamber 202 into compartments.
  • the volume of the chamber 202 may be decreased due to the space occupied by the partitions between the pores of the porous material.
  • the filling time of the chamber 102 may be, for instance, reduced by to 1-4 minutes.
  • the porous material may further serve as a filter for species, such as aggregated proteins, which may otherwise block downstream components of the sweat sampling apparatus 200, such as the outlet 214 or the transportation path 104 of the electrowetting apparatus 100.
  • the porous material may assist to prevent fouling of the sweat sampling apparatus 200 by certain sweat components and impurities.
  • the porous material may, for instance, be selected to have specific adsorption properties for proteins and other species which it may be desirable to remove from the sweat entering or being contained within the chamber 202. Removing such impurities may be advantageous due to lessening the risk of the impurities altering the surface properties in the electrowetting apparatus 100, e.g.
  • the porous material may assist to mitigate the risk that such impurities impair the hydrophilic/hydrophobic balance required for release of the sweat droplets 124 from the outlet 214, and downstream migration of the sweat droplets 124.
  • the porous material comprises, or is, an incompressible frit-like material positioned adjacent the surface of the skin 206
  • the porous material may prevent, partly due to its incompressibility, blockage by bulging of skin 206 into the chamber 202.
  • the diameter of the pores of the porous material may be, for instance, in the range of 100 nm to 10 ⁇ m.
  • the diameter of the partitions between the pores may also, for instance, be in the range of 100 nm to 10 ⁇ m, in order to minimize the risk that such partitions themselves block the exit of a sweat gland 208.
  • the exit diameter of sweat glands 208 is typically in the range of about 60 ⁇ m to 120 ⁇ m.
  • sweat droplet 124 detachment is effected via electrowetting.
  • the upper surface of the substrate 210 is provided with electrodes 102 of the electrowetting apparatus 100. Detachment from the outlet 214 may occur when the sweat droplet 124 has grown to acquire a sufficiently large diameter that the sweat droplet 124 at least partially overlaps a pair of consecutive electrodes 102. In this case, once an electrowetting wave passes along the electrodes 102, the sweat droplet 124 spanning the pair of consecutive electrodes 102 may be dislodged from the outlet 214 accordingly.
  • the direction of transport along the transportation path 104 is denoted in FIG. 4 by the arrow 226.
  • the sweat droplets 124 may not be all of a uniform size or volume, because the sweat droplet 124 may continue to grow to varying degrees in the period between the sweat droplet 124 reaching the requisite diameter and the arrival of the electrowetting wave.
  • the sweat droplet 124 size may be determined by the frequency of the electrowetting wave.
  • the sweat sampling apparatus 200 comprises a substrate 228 which is separated from and opposes the substrate 210 delimiting the chamber 202.
  • the substrate 228 may enable control to be exerted over the volume of the sweat droplet 124. This may be achieved, for instance, by the substrate 228 being separated from the substrate 210 by a defined distance 230.
  • the sweat droplet 124 may increase in size until it makes contact with the substrate 228. In practice, when the sweat droplet 124 contacts the substrate 228, the sweat droplet 124 may become detached by "jumping" over to the substrate 228.
  • the separation distance 230 between the substrate 210 and the opposing substrate 228 may be selected such that it is large enough to ensure that the diameter of the forming sweat droplet 124, e.g. hemispherical sweat droplet 124, is sufficiently large before contacting the opposing substrate 228, i.e. the lower surface of the substrate 228 which opposes the upper surface of the substrate 210.
  • the substrate portion 122 described above in relation to the electrowetting apparatus 100 may be included in the substrate 228.
  • the lower surface of the substrate 228 may be provided with the electrodes 102 of the electrowetting apparatus 100.
  • migration of the sweat droplet 124 on the substrate 228 via the electrodes 102 may mean that sweat droplet 124 migration may occur when the next electrowetting wave reaches the sweat droplet 124 which has been released onto the substrate 228.
  • a sufficiently high electrowetting wave frequency may ensure transport/migration of sweat droplets 128 of relatively uniform size/volume to the sensor.
  • the size/volume of the sweat droplet 124 may be determined by both the electrowetting wave frequency and the separation 230 of the substrate 210 and the opposing substrate 228, i.e. since the sweat droplet 124 may grow in the period between electrowetting waves.
  • the sweat sampling apparatus 200 may be configured to enable control over the separation 230 between the substrate 210 and the opposing substrate 228. This may, for instance, be achieved by the sweat sampling apparatus 200 comprising a mechanism which engages at least one of the substrates 210, 228, which mechanism is configured to move at least one of the substrates 210, 228 such as to adjust the separation 230 of the substrates 210, 228.
  • the control exerted over the mechanism may be manual and/or automatic.
  • the sweat sampling apparatus 200 may, for example, control the separation 230 according to the sweat rate of the sweat gland 108.
  • the sweat sampling apparatus 200 may include a controller configured to control the mechanism to move at least one of the substrates 210, 228 according to a determined sweat rate, e.g. as detected via the processor(s) 152 and the sensing circuit 134.
  • the sweat sampling apparatus 200 may be configured to control the separation 230 in a dynamic manner.
  • the sweat droplet 124 formation may risk being too rapid, and uncontrollable sweat droplet coalescence may occur. This may be mitigated by increasing the separation 230, since it may take a longer time to detach a larger sweat droplet 124 onto the substrate 228.
  • the number of sweat droplets 124 transported to the electrode(s) 136 may be relatively low. This issue may be alleviated by decreasing the separation 230 in order to increase the number of (smaller) sweat droplets 124 formed on the substrate 228.
  • migration of a sweat droplet 124 via the electrowetting apparatus 100 may be faster than formation, i.e. the protruding, of the subsequent sweat droplet 124. This is in order to ensure unambiguous sweat droplet definition, i.e. to ensure transport of a train of discrete sweat droplets.
  • the electrowetting apparatus 100 may maintain the discrete droplet characteristics of the sweat droplets 124 by ensuring rapid transport/migration relative to sweat droplet formation. This may have advantages over a continuous flow of sweat, especially at low sweat rates, in terms of lessening or avoiding diffusion of components, such as biomarkers, between sweat samples collected at different points in time.
  • the channel(s) along which the sweat droplets 124 are transported may be at least partially, and preferably fully, enclosed in order to minimize evaporation of the sweat droplets 124 during their transportation along the transportation path 104.
  • At least part of the sweat sampling apparatus 200 such as the chamber(s) 202 and the electrodes 102 of the electrowetting apparatus 100 may be included in a wearable device, such as a wearable patch.
  • the wearable device comprises an attachment arrangement, such as the above-described adhesive and/or fastenings, configured to enable attachment of the at least part of the sweat sampling apparatus 200 to a body part such that said inlets 204 receive sweat from the skin 206 of the body part.
  • an attachment arrangement such as the above-described adhesive and/or fastenings
  • the electrowetting apparatus 100 may include a (further) counter electrode 250 that does not participate in the transporting of the sweat droplet along the transportation path 104.
  • the electrical signal may be indicative of a capacitance between the at least one electrode 136 and the (further) counter electrode 250 spaced apart from the at least one electrode 136.
  • the further switch 142 that enables switching between the at least one counter electrode 126 being connected to and disconnected from the electrowetting transport control circuit 106 may be obviated.
  • the (further) electrode 250 may be continuously connected to the negative input of the operation amplifier 146.
  • Suitable steps may be taken to handle, e.g. dissipate to ground 112, residual charge from the (further) electrode 250 following provision of the electrical signal, as will be readily appreciated by the skilled person.
  • two electrodes 102 of the plurality of electrodes 102 may be employed for the sensing: the electrode 136 and a neighbouring/consecutive electrode 102 along the transportation path 104 with respect to the electrode 136.
  • the further switch 142 along with the switch 140, may be included to switch between the neighbouring/consecutive electrode 102 being connected to and disconnected from the electrowetting transport control circuit 106.
  • FIG. 7 provides a flowchart of a method 300 of operating an electrowetting apparatus according to an example.
  • the electrowetting apparatus has a plurality of electrodes arranged to define a transportation path along which sweat droplets are transportable, an electrowetting transport control circuit for charging and discharging the plurality of electrodes in sequence along the transportation path to enable transportation of sweat droplets, a sensing circuit, and a switch.
  • the electrowetting apparatus being operated in the method 300 may be the electrowetting apparatus 100 according to any of the embodiments described herein.
  • the method 300 comprises controlling 302 the switch to disconnect at least one electrode of the plurality of electrodes from the electrowetting transport control circuit.
  • an electrical signal is obtained from the at least one electrode, while the at least one electrode is disconnected from the electrowetting transport control circuit.
  • the electrical signal may be indicative of droplet presence, or absence, on the transportation path.
  • the method 300 further comprises controlling 306 the switch to, following the obtaining 304, connect the at least one electrode to the electrowetting transport control circuit.
  • the migration of droplet(s) along the transportation path can resume.
  • processors may, for instance, be the processor(s) 152 included in the electrowetting apparatus 100.
  • an chicken single-board microcontroller was employed by the inventors to control 302 the switch 140 to switch between said at least one electrode 136 being connected to and disconnected from the electrowetting transport control circuit 106, and to control the switching system 108A, 108B, 108C, 108D, 108E.
  • the apparatus, systems and methods of the present disclosure may be applied for non-invasive, semi-continuous and prolonged monitoring of biomarkers that indicate health and well-being, for example for monitoring dehydration, stress, sleep, children's health and in perioperative monitoring.
  • the present apparatus, systems and methods may be specifically applied to provide an early warning for sudden deterioration of patients in the General Ward and Intensive Care Unit, or for investigation of sleep disorders.
  • measurements may only be made in a spot-check fashion when a patient is visiting a doctor, although it is noted that the present disclosure may also be usefully applied in performing such spot-check measurements.
  • processors may be implemented by a single processor or by multiple separate processing units which may together be considered to constitute a "processor". Such processing units may in some cases be remote from each other and communicate with each other in a wired or wireless manner.
  • a computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.
  • a suitable medium such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130293246A1 (en) * 2010-11-17 2013-11-07 Advanced Liquid Logic Inc. Capacitance Detection in a Droplet Actuator
WO2019226919A1 (fr) * 2018-05-23 2019-11-28 Miroculus Inc. Contrôle de l'évaporation dans la microfluidique numérique
WO2019236682A1 (fr) * 2018-06-05 2019-12-12 Chronus Health, Inc. Dispositifs, cartouche et capteurs pour commander un mouvement de liquide et analyser des échantillons biologiques
US20200041445A1 (en) * 2018-07-31 2020-02-06 Taiwan Semiconductor Manufacturing Co., Ltd. Integrated biological sensing platform
WO2021074010A1 (fr) 2019-10-14 2021-04-22 Koninklijke Philips N.V. Appareil, système et procédé pour la surveillance de l'écoulement de sueur

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130293246A1 (en) * 2010-11-17 2013-11-07 Advanced Liquid Logic Inc. Capacitance Detection in a Droplet Actuator
WO2019226919A1 (fr) * 2018-05-23 2019-11-28 Miroculus Inc. Contrôle de l'évaporation dans la microfluidique numérique
WO2019236682A1 (fr) * 2018-06-05 2019-12-12 Chronus Health, Inc. Dispositifs, cartouche et capteurs pour commander un mouvement de liquide et analyser des échantillons biologiques
US20200041445A1 (en) * 2018-07-31 2020-02-06 Taiwan Semiconductor Manufacturing Co., Ltd. Integrated biological sensing platform
WO2021074010A1 (fr) 2019-10-14 2021-04-22 Koninklijke Philips N.V. Appareil, système et procédé pour la surveillance de l'écoulement de sueur

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
GAO ET AL.: "Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis", NATURE, vol. 529, 2016, pages 509 - 514, XP055766873, DOI: 10.1038/nature16521
MENA-BRAVODE CASTRO: "Sweat: A sample with limited present applications and promising future in metabolomics", J. PHARM. BIOMED. ANAL., vol. 90, 2014, pages 139 - 147, XP028820972, DOI: 10.1016/j.jpba.2013.10.048
SIMMERS: "Prolonged and localised sweat stimulation by iontophoretic delivery of the slowly-metabolised cholinergic agent carbachol", JOURNAL OF DERMATOLOGICAL SCIENCE, vol. 89, 2018, pages 40 - 51
TAYLOR: "Regional variations in transepidermal water loss, eccrine sweat gland density, sweat secretion rates and electrolyte composition in resting and exercising humans", EXTREM PHYSIOL MED, vol. 2, 2013, pages 4, XP021140478, DOI: 10.1186/2046-7648-2-4

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