Neural implant for microstimulation

Patent metadata

Field	Value
Publication number	US-11213687-B2
Application number	US-201615078484-A
Country	US
Kind code	B2
Filing date	Mar 23, 2016
Priority date	Feb 3, 2016
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

This disclosure provides systems and methods for delivering a neural stimulation pulse. A neural implant device can include an energy harvesting circuit configured to receive an input signal and generate an electrical signal based on the received input signal. A diode rectifier in series with the energy harvesting circuit can rectify the electrical signal. The energy harvesting circuit and the diode rectifier can be encapsulated within a biocompatible electrically insulating material. A neural electrode can be exposed through the biocompatible electrically insulating material. The neural electrode can be configured to deliver a neural stimulation pulse. The neural implant device can have a volume that is less than about 1.0 cubic millimeter.

First claim

What is claimed is:

1. A neural implant device, comprising:
an energy harvesting circuit configured to receive an input signal and generate an electrical signal based on the received input signal, wherein the energy harvesting circuit is encapsulated within a biocompatible electrically insulating material;
a neural electrode exposed through the biocompatible electrically insulating material, the neural electrode configured to deliver a neural stimulation pulse;
an energy storage device configured to store energy from an output of the energy harvesting circuit; and
a microelectromechanical systems (MEMS) magnetic reed switch configured to close and discharge the stored energy through the MEMS magnetic reed switch to the neural electrode in response to a wireless actuation signal having an AC component with a frequency that matches a resonant frequency of the switch.

2. The neural implant of claim 1 , wherein the energy harvesting circuit comprises an inductor in parallel with a capacitor.

3. The neural implant of claim 2 , further comprising a diode rectifier in series with the energy harvesting circuit, the diode rectifier configured to rectify the electrical signal, wherein the energy harvesting circuit and the diode rectifier are encapsulated within the biocompatible electrically insulating material.

4. The neural implant of claim 3 , wherein the diode rectifier, the inductor, the capacitor, and the neural electrode are included within a substantially cylindrical housing and arranged substantially along an axis of the substantially cylindrical housing.

5. The neural implant of claim 3 , wherein at least two of the capacitor, the inductor, and the diode rectifier are included on a single chip.

6. The neural implant of claim 2 , wherein the inductor has an inductance in the range of about 10 nH to about 500 μH.

7. The neural implant of claim 2 , wherein the inductor comprises a coil made from at least one of copper, aluminum, silver or gold wound around a ferrite core, wherein the coil is wound within the biocompatible electrically insulating material, and the biocompatible electrically insulating material is substantially free from air bubbles.

8. The neural implant of claim 2 , wherein the inductor has a diameter that is no greater than about 0.4 millimeters and a length that is no greater than about 1.0 millimeters.

9. The neural implant of claim 2 , wherein the capacitor has a capacitance in the range of about 1 pF to about 10 nF.

10. The neural implant of claim 2 , wherein the capacitor and the inductor form a circuit having a resonance frequency in the range of about 100 kHz to about 100 MHz.

11. The neural implant of claim 1 , wherein the switch is a normally open switch configured to close in response to the wireless actuation signal.

12. The neural implant of claim 11 , wherein the switch exhibits hysteresis, such that an amplitude of the wireless actuation signal required to close the switch is greater than an amplitude of the wireless actuation signal required to hold the switch in a closed position.

13. The neural implant of claim 12 , wherein the wireless actuation signal comprises:
a DC component selected to be of sufficient to magnitude to hold the switch in a closed position; and the AC component,
wherein a sum of amplitudes of the DC component and the AC component is sufficient to close the switch.

14. The neural implant of claim 1 , wherein the neural implant device has a volume that is less than about 1 cubic millimeter.

15. The neural implant device of claim 14 , wherein the neural implant device has a volume that is less than about 0.5 cubic millimeters.

16. The neural implant of claim 1 , wherein the biocompatible electrically insulating material comprises at least one of parylene, silicone, and epoxy.

17. The neural implant of claim 1 , wherein the energy harvesting circuit comprises at least one piezoelectric energy harvester.

18. The neural implant of claim 1 , wherein the switch is configured to discharge the stored energy to the neural electrode when the switch is in a closed position.

19. The neural implant of claim 1 , further comprising an antenna coupled to the energy harvesting circuit, wherein the antenna is configured to:
receive the input signal from a transmitter; and
provide the input signal to the energy harvesting circuit.

20. The neural implant of claim 1 , wherein the MEMS magnetic reed switch includes:
a substrate formed of a non-magnetic material;
a first contact formed of a magnetic material disposed on the substrate; and
a second contact formed of a magnetic material and having a first end fixed to the substrate and a second end suspended above the first contact when the switch is in an open state, the second contact bending downward to touch the first contact and close the switch responsive to a magnetic field of sufficient amplitude and having a frequency matching a resonant frequency of the second contact being applied to the MEMS magnetic reed switch.

21. A neural implant device, comprising:
an energy harvesting circuit configured to receive an input signal and generate an electrical signal based on the received input signal, wherein the energy harvesting circuit is encapsulated within a biocompatible electrically insulating material;
a neural electrode exposed through the biocompatible electrically insulating material, the neural electrode configured to deliver a neural stimulation pulse;
an energy storage device configured to store energy from an output of the energy harvesting circuit; and
a switch configured to close and discharge the stored energy through the switch to the neural electrode in response to a wireless actuation signal having an AC component with a frequency that matches a resonant frequency of the switch, the switch exhibiting hysteresis, such that an amplitude of the wireless actuation signal required to close the switch is greater than an amplitude of the wireless actuation signal required to hold the switch in a closed position.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Bernstein Jonathan
• Freeman Daniel
• Irion Reed
• Ingersoll Brett
• Duwel Amy
• Czarnecki Andrew
• Daniels Brian
• Achyuta Anilkumar Harapanahalli
• Mclaughlin Bryan

Classifications

• A61N1/36125

  Details of circuitry or electric components · CPC title

• A61N1/3787

  from an external energy source · CPC title

• A61N1/3756

  Casings with electrodes thereon, e.g. leadless stimulators · CPC title

• A61N1/37205

  Microstimulators, e.g. implantable through a cannula · CPC title

• H02N2/18

  producing electrical output from mechanical input, e.g. generators (for measurement devices G01) · CPC title