Systems, and methods for neurostimulation and neurotelemetry using semiconductor diode systems
View Patent ↗Methods and systems for neurostimulation and/or neurotelemetry of electrically-excitable biological tissue. Embodiments include implanting single or multiple semiconductor diodes and applying a high frequency electrical volume current. Neurostimulation embodiments include local rectification of the volume current by the diode, which can provide a pulsating electrical waveform capable of locally stimulating neural tissue, hi neurotelemetry embodiments, semiconductor diodes can be placed in contact with excitable tissue and a low level electrical carrier wave can be passed through the tissue and implanted diode whereby low level tissue bioelectric events intermodulate with the carrier wave and encode bioelectrical effects. Remote detection and amplitude demodulation of the volume-conducted carrier wave can allow recovery of the bioelectrical waveform and provide a neurotelemetry function, hi other embodiments, implanted diodes are placed in series with a pressure switch or piezoelectric material which enables their function only with the focal application of an acoustic pressure wave. This enables a selectivity amongst multiple diode channels by acoustic wave focusing or alternately by a process of range-gating of a surface applied electrical current to the arrival time of an acoustic wave at a particular device.
1. A method of providing neurostimulation, the method comprising:
implanting a diode having two nodes into biological tissue such that the nodes of the diode are directly electrically coupled to excitable neural tissue and at least one node of the diode forms an antenna;
providing a radio frequency exciter proximal to tissue overlying the diode, wherein the radio frequency exciter is configured to emit a radio frequency electromagnetic output;
modulating the radio frequency electromagnetic output with a pulse width and rate;
varying the power level of the radio frequency exciter; and
creating a pulsed current flow from the diode by receiving the modulated radio frequency electromagnetic output with the antenna, wherein the pulsed current flow is sufficient to provide neurostimulation of the excitable neural tissue.
2. The method of claim 1 wherein the nodes are electrically coupled to a dipole.
3. The method of claim 2 wherein the dipole is between 1 millimeter and 1 centimeter in length.
4. The method of claim 2 wherein the dipole is between 1 centimeter and 5 centimeters in length.
5. The method of claim 1 wherein the biological tissue comprises brain tissue, muscle tissue, or nervous system tissue.
6. The method of claim 1 wherein the diode is a semiconductor diode.
7. The method of claim 1 wherein radio frequency exciter is configured to emit radio waves in the microwave frequency range.
8. The method of claim 1 wherein radio frequency exciter is configured to emit radio waves at a frequency between 100 MHz to 8 GHz.
9. The method of claim 1 wherein the radio frequency output is modulated so that it is pulsed for a time period between 100 microseconds and 10 milliseconds and so that it is pulsed in the range of 1 to 200 pulses per second.
10. The method of claim 1 wherein the diode is configured to rectify the radio frequency output from the radio frequency exciter.
11. The method of claim 1 wherein the diode is configured to be placed in the lumen of an 18 gauge needle.
12. The method of claim 1 wherein the diode is arranged in a bridge configuration with additional diodes.
13. A neurostimulation system comprising:
a radio frequency exciter configured to emit a microwave frequency electromagnetic output; and
a diode having two nodes, the diode configured to receive the microwave frequency electromagnetic output from the radio frequency exciter by using at least one of its nodes as an antenna such that the node is configured to be directly electrically coupled to excitable neural tissue, and to rectify the microwave frequency electromagnetic output to provide a pulsating and monopolar current, wherein the pulsating and monopolar current is sufficient to provide neurostimulation of excitable neural tissue.
14. The neurostimulation system of claim 13 wherein the radio frequency exciter is configured to emit radio waves at a frequency between 100 MHz to 8 GHz.
15. The neurostimulation system of claim 13 further comprising an electrical switch in parallel or series with the diode.
16. The neurostimulation system of claim 15 wherein the switch comprises a polymer material loaded with a finely dispersed particulate conductive phase.