WO2025102053A1 - Rotational freeform stimulator and multichannel freeform stimulator - Google Patents

Abstract

A rotational freeform stimulator (RFS) includes both a microfluidic portion referred to as the µFS and also an electrical component. The µFS includes rotational components. The rotational components include electrodes embedded in electrolytic gel. The µFS also includes a return electrode Er embedded in gel, as well as a discharge electrolytic gel. The gels surrounding the electrodes (E1 and E2) alternate between driving current to neurons when rotated to touch the gray layer of conductive gel surrounding Er, and discharge when rotated to touch the discharge gel. Current delivered to each electrode is carefully controlled and accounted for by current sources that are operated in a control circuit via the electrical components. In some embodiments, the RFS may include more than one stimulation channel and in those instances is referred to as a multichannel freeform stimulator (MFS).

Description

ROTATIONAL FREEFORM STIMULATOR AND MULTICHANNEL FREEFORM STIMULATOR CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application No. 63/597,844 filed on November 10, 2023, which is incorporated by reference, herein, in its entirety. GOVERNMENT RIGHTS [0001] This invention was made with government support under grant numbers DC018300 and NS110893, awarded by the National Institutes of Health. The government has certain rights in the invention. FIELD OF THE INVENTION [0002] The present invention relates generally to medical devices. More particularly, the present invention relates to a rotational freeform stimulator and multichannel freeform stimulator. BACKGROUND OF THE INVENTION [0003] The therapeutic goal of an implantable neuroprosthesis is to restore or regulate the function of a neural system. Examples of implantable neuroprostheses include the spinal cord stimulator for the regulation of chronic pain, the cochlear implant for the restoration of auditory input, and the deep brain stimulator for the treatment of the symptoms of Parkinson’s disease. These devices are all variations of the Implantable Pulse Generator (IPG) that delivers short, charge-balanced, biphasic current pulses through metal electrodes implanted in the body to affect neural targets. This type of waveform removes the risk of adverse electrochemical reactions that can occur at the metal-tissue interface when charge accumulates on the electrode. Pulses delivered by the IPG evoke phase-locked action potentials in the target neural population. [0004] The limitations of charge-balanced pulsatile stimulation encouraged recent exploration of other types of stimulation patterns. Direct current (DC) and other non-charge- balanced stimulation patterns – referred to here as freeform stimulation – can be used to excite, inhibit, and modulate neural sensitivity. However, delivering long duration or DC through conventional metal electrodes in the body leads to harmful electrochemical reactions. Most of the new approaches developed to overcome this focus on prolonging the delivery of freeform stimulation by delaying, but not avoiding, either the adverse electrochemical reactions themselves (e.g. by adding a coating to the electrode surface) or the effects of the byproducts on the tissue (e.g. by separating the electrode/electrolyte interface from the tissue). [0005] In contrast to conventional pulsatile stimulation that evokes action potentials in phase with pulse presentations, direct current (DC) stimulation has shown successful results in clinical applications with its ability of not only excitation but also inhibition and modulation of synaptic connectivity. Despite its versatility, DC and low frequency electric fields cannot be delivered for long durations by a neural implant that uses metal electrodes due to safety concerns such as pH changes, electrolysis, and corrosion. [0006] A Safe Direct Current Stimulator (SDCS) device allowed a direct current to be delivered safely to neural targets from an implantable device. This has not been possible previously since all conventional neural implants must use charge balanced biphasic pulses to avoid electrochemical reactions at the electrodes, constraining neurons to responding with action potentials that are phase-locked to pulse presentations. SDCS removes this constraint, opening a path for neuromodulation that has never been available previously. [0007] The design was improved to allow ANY waveform to be delivered (not just DC), renaming it Freeform Stimulator (FS). The FS solved many difficult practical problems with this device development. The FS has significant benefits for the vestibular prosthetic application and as a therapy for blocking peripheral nociceptive pain. However, two key problems kept this technology from becoming commercialized: the lack of reliability associated with the actuation mechanism and inability to create multiple channels easily. [0008] Accordingly, there is a need in the art for a rotational freeform stimulator and multichannel freeform stimulator. SUMMARY OF THE INVENTION [0009] The foregoing needs are met, to a great extent, by the present invention which provides a device for stimulation including an interior cylinder and a housing cylinder. The housing cylinder defines an inner lumen, and the inner lumen is sized to receive the interior cylinder. The device includes a first and a second electrode. The first and second electrodes are disposed in a gel. The gel is ionically conductive and mechanically stable. The first and second electrodes are disposed on the interior cylinder. The device also includes a return electrode for discharging current to a target. [0010] In accordance with an aspect of the present invention, further includes a motor, a phase indicator, and a commutator. The first and second electrodes are rotated in and out of contact with the return electrode to be discharged to the target. [0011] In accordance with another aspect of the present invention, a device for stimulation includes a microfluidic component and an electronic component. The microfluidic component includes an interior cylinder and a housing cylinder. The housing cylinder defines an inner lumen, and the inner lumen is sized to receive the interior cylinder. The device includes a first and a second electrode. The first and second electrodes are disposed in a gel. The gel is ionically conductive and mechanically stable. The first and second electrodes are disposed on the interior cylinder. The device also includes a return electrode for discharging current to a target. The electronic component includes a motor and a phase indicator. [0012] In accordance with still another aspect of the present invention, the device includes a commutator. The device includes two or more microfluidic components. The device includes a power source, which can take the form of a battery. [0013] In accordance with another aspect of the present invention, a device for stimulation includes a rotating disk. The rotating disk defines an interior space. The device includes a motor, wherein the motor is configured to rotate the rotating disk. The device includes a first and a second electrode. The first and second electrodes are disposed within the interior space of the rotating disk. The interior space of the rotating disk is filled with a gel. The gel is ionically conductive and mechanically stable. The device also includes a return electrode for discharging current to a target. [0014] In accordance with another aspect of the present invention, the device includes a circuit board. The rotating disk includes a component for providing electrical connection with the circuit board. The device includes an end plate. The end plate is filled with a gel, wherein the gel is ionically conductive and mechanically stable. The return electrode is disposed within the end plate. The first and second electrodes are rotated in and out of contact with the return electrode to be discharged to a target. The device includes two or more rotating disks. The device includes a power source. The power source can take the form of a battery. [0015] In accordance with another aspect of the present invention, a device for stimulation includes a rotating component. The device includes a motor. The motor is configured to rotate the rotating component. The device includes a first and a second electrode disposed on the rotating component. The device includes a gel. The gel is ionically conductive and mechanically stable. The device also includes a return electrode for discharging current to a target though the gel. BRIEF DESCRIPTION OF THE DRAWINGS [0016] The accompanying drawings provide visual representations, which will be used to more fully describe the representative embodiments disclosed herein and can be used by those skilled in the art to better understand them and their inherent advantages. In these drawings, like reference numerals identify corresponding elements and: [0017] FIGS.1A, 1B, and 1C illustrate schematic diagrams of the μFS and its operation through three of its operational states (state 3, state 5, and state 7, respectively – described further in FIG.14). [0018] FIG.1D illustrates a perspective view of a prototype for a rotational freeform stimulator (RFS) device according to an embodiment of the present invention. [0019] FIG.1E illustrates a graphical view of current amplitudes for a prototype of an embodiment of the present invention. [0020] FIGS.2-5 illustrate perspective views of the outer housing and the inner cylinder of an μFS, according to an embodiment of the present invention. [0021] FIG.6 illustrates a block diagram of a multichannel freeform stimulator (MFS), according to an embodiment of the present invention. [0022] FIGS.7 and 8 illustrate side views of an RFS, according to an embodiment of the present invention. [0023] FIGS.9 and 10 illustrate side views of internal components of an RFS, according to an embodiment of the present invention. [0024] FIGS.11, 12, 13, and 14 illustrate partially exploded views of an RFS, according to an embodiment of the present invention. [0025] FIG.15 illustrates a block diagram of essential electronic elements to control the RFS, according to an embodiment of the present invention. [0026] FIGS.16-21 illustrate schematic diagrams for essential electronic elements of a single-channel RFS, according to an embodiment of the present invention. [0027] FIG.22 illustrates a flow diagram of the operation of an RFS, according to an embodiment of the present invention. DETAILED DESCRIPTION [0028] The presently disclosed subject matter now will be described more fully hereinafter with reference to the accompanying Drawings, in which some, but not all embodiments of the inventions are shown. Like numbers refer to like elements throughout. The presently disclosed subject matter may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Indeed, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated Drawings. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. [0029] The present invention solves two key problems with the previous technologies. With the present invention the actuation problem is solved as well as the problem of providing multiple channels. The rotational freeform stimulator (RFS) solves the actuation problem by developing a design that is driven with a simple implant-size (< 1cm) DC motor that can be acquired off-the-shelf. The rotational design allows many independent channels to be driven using the same motor, creating the Multichannel Freeform Stimulator (MFS). [0030] The Freeform Stimulator (FS) (a.k.a. Safe Direct Current Stimulator (SDCS)) was developed with the intention of creating a neural implant that would not be constrained by the need to deliver charge balanced biphasic pulses to neural targets. Using ionic current without this constraint supports excitation, inhibition, and modulation of neural sensitivity by controlling extracellular potential. The FS was shown to dramatically improve the vestibular prosthesis and block peripheral nociceptive pain. Many challenges associated with the reliability, fabrication, and power consumption of this device were also addressed. [0031] Conventional neural stimulation uses electrodes positioned near neural targets that are confined to deliver charge balanced biphasic pulses to maintain safety. Prolonged current results in faradaic reactions that create electrolysis, pH changes, and electrode corrosion. In contrast, the FS is designed to deliver any waveform with no theoretical limit on bandwidth or charge accumulation. Two electrodes used in the device alternate between delivering the desired waveform to the tissue and discharging, while the second electrode does the opposite, switching control back and forth between the two electrodes. This way the charge accumulated on either electrode is always discharged in the subsequent phase of operation. [0032] The FS delivers continual current through ultrathin microcatheter tubes filled with electrolytic gel. Ionic direct current (iDC) from the device, that is electrical current delivered via tubes filled with electrolyte, rather than through wires, extracellularly to neurons has been shown to modulate the membrane potential of the neurons to sensitize or desensitize neural membranes to synaptic inputs. [0033] FS technology can be used for cortical neuromodulation. Conventional neural implants have been confined to deliver charge balanced biphasic current pulses to maintain electrochemical safety. While it is possible to modulate neural firing with small electrodes positioned near the target neurons, there are clear limitations to their ability to deliver natural sensation or motion. This is likely because their ability to modulate network activity is limited to evoking spikes on neighboring neurons in phase with pulse presentations. Alternatively, transcranial direct current stimulation (tDCS) has been used acutely at the surface of the skin to modulate cortical network behaviors. tDCS can modulate neural activity more naturally by subtly altering membrane potential and neural sensitivity but not evoking action potentials on its own. However, because the stimulation source is located far from the target on the surface of the head, the cortical activation area is large and the electric field direction is unpredictable. [0034] FS technology enables the creation of a new class of bioelectronic prostheses that allow virtually unrestricted control of extracellular voltages to excite, inhibit, and modulate sensitivity of neural activity and target cortical networks with pinpoint accuracy compared to tDCS. This technology can be implanted near the neural targets like the conventional implants, but it also has the ability to subtly modulate neural network behavior in a way that is similar to tDCS, rather than in an all-or-none fashion of the pulsatile implants. [0035] The present invention is directed to a new implementation of FS technology in the form of a rotational freeform stimulator (RFS). The RFS includes both a microfluidic portion referred to as the μFS and also an electrical component. These components work in tandem to provide stimulation to the desired target. The μFS includes inner and outer cylinders. The inner cylinder includes carbon mesh (or other high charge capacity) electrodes embedded in electrolytic gel composed of an electrolyte gelled with Agar (or a hydrogel with high ionic conductivity and stable mechanical properties). The outer cylinder also includes a return electrode Er embedded in gel, as well as a discharge electrolytic gel. The gels surrounding the electrodes (E1 and E2 in FIG.1) alternate between driving current to neurons when actuated to touch the layer of conductive gel surrounding Er, and discharge when actuated to touch the discharge gel. Current delivered to each electrode is carefully controlled and accounted for by current sources that are operated in a control circuit via the electrical components. In some embodiments, the RFS may include more than one stimulation channel and in those instances is referred to as a multichannel freeform stimulator (MFS). [0036] One exemplary design of the RFS includes one stimulation channel. The number of channels included in the exemplary embodiments described herein should not be considered limiting, and as described further herein the device of the present invention can also include embodiments with multiple channels. [0037] FIGS.1A, 1B, and 1C illustrate schematic diagrams of the μFS and its operation through three key states (state 3, state 5, and state 7, respectively). The μFS 10 includes E1 and E2 embedded in a conductive gel. The electrodes E1 and E2 are rotated on internal cylinder 12 within housing cylinder 14. A return electrode Er is disposed in the housing cylinder and allows for charge to be transmitted from E1 and E2 through Er to tissue 16 for stimulation. The return electrode Er is also embedded in a conductive gel 17. A space 18 between the internal cylinder 12 and the housing cylinder 14 is filled with mineral oil to prevent degradation and evaporation of the conductive gel and provide electrical isolation. [0038] Further as illustrated with respect to FIGS.1A, 1B, and 1C electrodes E1 and E2 remain charge-balanced by alternating between driving current and being discharged. In state 3, illustrated in FIG.1A, E1 is driving current through the tissue, and E2 is being discharged. In state 5, illustrated in FIG.1B, the internal cylinder 12 is rotating to transition to drive current using E2. In state 7, illustrated in FIG.1C, E2 is driving the current through the tissue, and E1 is being discharged. The device continues to cycle through these states, described further herein, to continue driving and discharging current through E1 and E2. [0039] FIG.1D illustrates a perspective view of a prototype for an RFS device according to an embodiment of the present invention. FIG.1D illustrates both the μFS and the electrical components of the device 1. A motor 20 drives the internal cylinder 12, a phase indicator 22 determines an absolute location of the inner cylinder 12, and commutators 24, 26 provide continual connection to E1 and E2. The device 1 illustrated in FIG.1D is driven by a DC motor 20 with feedback from a phase indicator 22 to supply an exact position of the internal cylinder 12. The feedback from the phase indicator 22 is necessary to precisely time the charging and discharging of E1 and E2 electrodes. Slip-ring commutators 24, 26 are used to provide continual electrical connection to the E1 and E2 electrodes on the inner cylinder. [0040] FIG.1E illustrates a graphical view of current amplitudes for a prototype of an embodiment of the present invention. The upper plots show two DC amplitudes from an existing prototype. The lower left plot shows a charge balanced sinusoidal AC current and the lower right plot shows DC-offset sinusoid. Vertical scale bar is 100μA. Vertical dashed lines denote state transitions. [0041] FIGS.2-5 illustrate perspective views of the outer housing and the inner cylinder of an μFS, according to an embodiment of the present invention. The μFS 10 includes E1 and E2 embedded in a conductive gel. The electrodes E1 and E2 are rotated on internal cylinder 12 within housing cylinder 14. A return electrode E_r allows for charge to be transmitted from E1 and E2 through E_r to tissue for stimulation. The return electrode E_r is also embedded in a conductive gel. Commutators 24 and 26 provide continual electrical connection to the E1 and E2 electrodes on the inner cylinder. [0042] In another exemplary embodiment of the present invention, a 3-channel RFS device is used to enable rodent behavioral studies that use a headpost or a backpack. For convenience, this design is referred to as the Multichannel Freeform Stimulator (MFS) to differentiate it from the RFS. [0043] FIG.6 illustrates a block diagram of an MFS, according to an embodiment of the present invention. The device 2 contains a power source 28. The power source as illustrated in FIG.6 is a 3.7V Li-Ion battery to provide backup power when the external battery is replaced. The motor 20 will be positioned above the μFS cylinders 12 and will drive the cylinders via a gear 30 to address space constraints. Three independent μFS components 12 are driven by the same motor 20 and the same gear and shaft 30. The device 2 also includes an easily accessible on/off switch 32 and LEDs 34 to indicate battery voltage and interruption in output electrical current flow for each channel. A USB-C connector 36 will provide input for external power, communication with the microcontroller to program the output of the device and accept a real-time input from external electronics to allow control of each output channel if programmable output is insufficient. An API for programming will control the device through the USB-C connection 36. A Bluetooth® connection can be included to allow wireless communication with the device to command stimulation parameters and receive impedance readings. [0044] One need for this implementation is that the MFS must provide three electrically independent iDC stimulation channels capable of delivering up to 1mA of current each. This need is addressed by concentrically stacking the μFS inner and outer cylinders and driving all inner cylinders using one motor along the same shaft. Electrical isolation implies that there will be two independent current sources and sinks for each channel. [0045] In a preferred embodiment, all electrodes in the device remain charge-balanced independent of iDC output for a minimum of one month, and the device provides reliable operation for a minimum of 3 months The FS has a current sensor in the device that constantly delivers feedback to the control system to ensure that the output of the device matches the expected output. This same sensor will be used by the MFS for each channel to ensure that any unexpected output (for example if one of the inner cylinders is shorted) triggers the corresponding LED indicator. [0046] The gelled channels are currently made of an Agar-gelled electrolyte. This method of making the gel is sufficient for stability, but it is possible that it may degrade due to friction given the long operation requirements. In some embodiments, the mechanical stability of the gel can be strengthened using a variety of biocompatible polymers and textiles (e.g. unbleached cotton). These techniques can be used to strengthen the material as necessary. An alternative composition is using hydrogels that maintain high conductivity and high mechanical stability. [0047] The MFS is self-contained and contains internal power for backup or short duration operation (while external battery is being replaced). The MFS is small enough to allow placement in a rodent (rat) backpack for extended behavioral studies. The MFS has an on/off switch and a power input for an external battery. It allows at least 12 hours of use on one external AA battery. The MFS includes a current interruption/“compliance voltage reached” indicator for each channel and a battery life indicator. The MFS is programmable to allow predefined waveforms to be delivered from each output independently. [0048] FIGS.7 and 8 illustrate side views of an RFS, according to an embodiment of the present invention. The device 100 includes a motor 102 and a stimulator compartment 104. The motor 102 and the stimulator compartment 104 are connected via axel 106. A circuit board 108 and rotating disks 110 are housed within the stimulator compartment 104. An end plate 112 includes a return electrode (Er) for the device 100. These components will be described further herein. [0049] FIGS.9 and 10 illustrate side views of internal components of an RFS, according to an embodiment of the present invention. The motor 102, the circuit board 108, and end plate 112 are static. The rotating disk 110 is rotated by the motor 102. The motor 102 and the stimulator compartment 104 are connected via axel 106. More particularly axel 106 connects the motor 102 and rotating disk 110, such that the motor 102 can rotate the rotating disk 110. The rotating disk 110 includes a component 114 to contact and or communicate with the circuit board 108. This component 114 can take the form of a wire, needle, pin, projection, commutator, or any other element known to or conceivable to one of skill in the art to allow for communication between the circuit board 108 and the rotating disk 110. A single component 114 can be used for communication or a number of components 114 can be used in tandem. Wires 116 allow for electrical communication into and out of the device 100. [0050] FIGS.11, 12, 13, and 14 illustrate partially exploded views of an RFS, according to an embodiment of the present invention. FIG.11 illustrates the device 100 of the present invention, with the circuit board 108 removed from the device, with side and top-down views of the circuit board 108. The circuit board 108 can include one or more channels 118 to accommodate the component 114 of the rotating disk 110 and allow for communication between the rotating disk 110 and the circuit board 108. [0051] FIGS.12 and 13 illustrate the device 100 of the present invention, with the circuit board 108 removed from the device, with side and top-down views of the circuit board 108, and with the rotating disk 110 removed from the device, with side and top-down views of the two halves of the rotating disk 110. The rotating disk 110 includes a first disk 120 and a second disk 122. The first side 120 includes a first electrode (E1) and a second electrode (E2). E1 and E2 are disposed on a first side 124 of the first disk 120. The component 114 for communication with the circuit board 108 is disposed on a second side 126 of the first disk 120. The component 114 can include prongs, wires, or other means of communication for E1, E2, a ground (gnd), and encoding (enc). Together the first disk 120 and the second disk 122 of the rotating disk 110 define an interior space 128 that can be filled with a gel 130, such as an agar gel. The gel is configured to conduct electrical signal from the electrodes and can take the form of any gel or other conductive substance known to or conceivable to one of skill in the art. E1 and E2 alternating between driving current and being discharged via Er, as the rotating disk 110 rotates causing contact between E1 and E2 and Er. Additionally, as the rotating disk 110 rotates, contact components 114 contact the circuit board for controlling and actuating the current driving and discharge of the device. [0052] FIG.14 illustrates the device 100 of the present invention, with the circuit board 108 removed from the device 100, with side and top-down views of the circuit board 108, with the rotating disk 110 removed from the device 100, with side and top-down views of the two disks of the rotating disk 110, and with the end plate 112 removed from the device 100, with side and top-down views of the two disks of the end plate 112. Like the rotating disk 110 the end plate 112 includes a first disk 132 and a second disk 134, which when coupled together define an interior space for a gel 136. The second disk 134 of the end plate 112 provides a base for the return electrode (Er). Er communicates through the conductive gel 136. Er discharges current to a target via componentry coupled to the end plate. [0053] In practice, as illustrated in FIGS.7-14 the motor 102 rotates rotating disk 110. This rotational movement along with the corresponding contact between the gel, allows for the charging and discharging of electrodes E1 and E2. The electrodes E1 and E2 are rotated on on the disk, while return electrode Er allows for charge to be transmitted from E1 and E2 through Er to tissue for stimulation. [0054] The gelled channels are currently made of an Agar-gelled electrolyte. This method of making the gel is sufficient for stability, but it is possible that it may degrade due to friction given the long operation requirements. In some embodiments, the mechanical stability of the gel can be strengthened using a variety of biocompatible polymers and textiles (e.g. unbleached cotton). These techniques can be used to strengthen the material as necessary. An alternative composition is using hydrogels that maintain high conductivity and high mechanical stability. [0055] This design is scalable both in terms of size and the number of rotating disks included. The design also allows for ease of manufacture, adjustability of tension between the layers of gel, and can be scaled without any changes to the electronics. [0056] FIG.15 illustrates a block diagram of essential electronic elements of an RFS, according to an embodiment of the present invention, and FIGS.16-21 illustrate schematic diagrams for essential electronic elements of a single-channel RFS, according to an embodiment of the present invention. Power management converts the unregulated battery input voltage into a regulated low-voltage line (VCC) to power components like the microcontroller and a regulated high-voltage line (VCOMPLIANCE or VCOMP) to supply the output current through higher impedance microfluidic channels. The current supplies control the output current (I1 and I2) through each electrode. A feedback sensor monitors the current output and provides feedback to the system (VFEEDBACK). A multi-channel device would require additional current output feedback and current supplies blocks (one each per channel). The motor driver controls the rotational speed of the motor using pulse width modulation (PWM). The angular position or phase of the device is represented by the signal (VPOSITION) which determines when the device should switch operation states. In order to set the desired output, the user supplies a voltage (VCONTROL) whose value is mapped to a known current magnitude. Other digital I/Os provide a user interface to establish operational settings, program, and monitor the output of the device. [0057] FIG.22 illustrates a flow diagram of the operation of an RFS, according to an embodiment of the present invention. The operation of the device is controlled via a state machine. Half of the conditions to switch states are defined by a set time period while the other half are defined by the angular position or phase of the device. The four significant positions are: 1, where electrode 2 first comes into contact with the return electrode; 2, where electrode 2 first comes into contact with the output port; 3, where electrode 1 first comes into contact with the return electrode; and 4, where electrode 1 first comes into contact with the output port. The desired output current through the tissue is labeled as ISET, which is determined by VCONTROL from the hardware block diagram above. In states 2-4 with the white boxes, electrode 1 is in contact with the output port to the tissue and the current through this electrode (I₁) provides the output current to the tissue. In states 6-8 with the grey boxes, electrode 2 is in contact with the output port to the tissue and the current through this electrode (I₂) provides the output current to the tissue. In states 1 and 5 with the gradient boxes, both electrodes are in contact with the output port to the tissue and there is a smooth transition in control of the output current from one electrode to the other. This transition or switch takes place over the time period T_S. At every time step through the state machine, the charge on each electrode (Q₁ and Q₂) is calculated. In the bolded states 3 and 7, electrodes 2 and 1 are discharged respectively. The discharge current through each electrode (I_D) is calculated by dividing the total accumulated charge on that electrode when entering the discharge state by the period of time allowed for discharging in that state (T_D). The rotational speed of the device is selected such that the time both electrodes are in contact with the output port is not less than TS and the time each electrode is in contact with the return electrode is not less than TD. [0058] Function of the present invention can be carried out in conjunction with a processor included in the electronics depicted as “Microcontroller” in FIG.15 and FIG.19, computer, non-transitory computer readable medium, or alternately a computing device or non- transitory computer readable medium incorporated into the medical device associated with the present invention. [0059] A non-transitory computer readable medium is understood to mean any article of manufacture that can be read by a computer. Such non-transitory computer readable media includes, but is not limited to, magnetic media, such as a floppy disk, flexible disk, hard disk, reel-to-reel tape, cartridge tape, cassette tape or cards, optical media such as CD-ROM, writable compact disc, magneto-optical media in disc, tape or card form, and paper media, such as punched cards and paper tape. The computing device can be a special computer designed specifically for this purpose. The computing device can be unique to the present invention and designed specifically to carry out the method and operation of the present invention. [0060] The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. While exemplary embodiments are provided herein, these examples are not meant to be considered limiting. The examples are provided merely as a way to illustrate the present invention. Any suitable implementation of the present invention known to or conceivable by one of skill in the art could also be used.

Claims

What is claimed is: 1. A device for stimulation comprising: an interior cylinder; a housing cylinder, wherein the housing cylinder defines an inner lumen, and wherein the inner lumen is sized to receive the interior cylinder; a first and a second electrode, wherein the first and second electrodes are disposed in a gel, wherein the gel is ionically conductive and mechanically stable, and wherein the first and second electrodes are disposed on the interior cylinder; and a return electrode for discharging current to a target.

2. The device of claim 1 further comprising a motor.

3. The device of claim 1 further comprising a phase indicator.

4. The device of claim 1 further comprising a commutator.

5. The device of claim 1 wherein the first and second electrodes are rotated in and out of contact with the return electrode to be discharged to the target.

6. A device for stimulation comprising: a microfluidic component comprising: an interior cylinder; a housing cylinder, wherein the housing cylinder defines an inner lumen, and wherein the inner lumen is sized to receive the interior cylinder; a first and a second electrode, wherein the first and second electrodes are disposed in a gel, wherein the gel is ionically conductive and mechanically stable, and wherein the first and second electrodes are disposed on the interior cylinder; a return electrode for discharging current to a target; an electronic component comprising: a motor; and a phase indicator.

7. The device of claim 6 further comprising a commutator.

8. The device of claim 6 comprising two or more microfluidic components.

9. The device of claim 6 further comprising a power source.

10. The device of claim 9 wherein the power source comprises a battery.

11. A device for stimulation comprising: a rotating disk, wherein the rotating disk defines an interior space; a motor, wherein the motor is configured to rotate the rotating disk; a first and a second electrode, wherein the first and second electrodes are disposed within the interior space of the rotating disk, and wherein the interior space of the rotating disk is filled with a gel, wherein the gel is ionically conductive and mechanically stable; and a return electrode for discharging current to a target.

12. The device of claim 11 further comprising a circuit board.

13. The device of claim 12 wherein the rotating disk comprises a component for providing electrical connection with the circuit board.

14. The device of claim 11 further comprising an end plate.

15. The device of claim 14 wherein the end plate is filled with a gel, wherein the gel is ionically conductive and mechanically stable.

16. The device of claim 14 wherein the return electrode is disposed within the end plate.

17. The device of claim 11 wherein the first and second electrodes are rotated in and out of contact with the return electrode to be discharged to a target.

18. The device of claim 11 further comprising two or more rotating disks.

19. The device of claim 11 further comprising a power source.

20. The device of claim 19 wherein the power source comprises a battery.

21. A device for stimulation comprising: a rotating component; a motor, wherein the motor is configured to rotate the rotating component; a first and a second electrode disposed on the rotating component; a gel, wherein the gel is ionically conductive and mechanically stable; and a return electrode for discharging current to a target though the gel.