Neurostimulator
View Patent ↗Methods and devices for stimulating nerves are disclosed. In one embodiment adapted for stimulating excitable tissue, the invention includes drive circuitry, an acoustic transducer and a pair of electrodes.
1. An implantable neurostimulator comprising:
a first electrode electrically coupled to a first piezoelectric material;
a second electrode electrically coupled to the first piezoelectric material;
a third electrode electrically coupled to a second piezoelectric material;
a fourth electrode electrically coupled to the second piezoelectric material;
a biocompatible coating surrounding first and second piezoelectric materials;
where the first piezoelectric material is configured to provide an electrical potential to biological tissue through the first and second electrodes in response to an ultrasound signal;
where the second piezoelectric material is configured to provide an electrical potential to biological tissue through the third and fourth electrodes in response to an ultrasound signal;
where the first and second piezoelectric materials have different resonant frequencies; and
where the first and second electrodes protrude through the biocompatible coating.
2. The implantable neurostimulator of claim 1 , where the biocompatible coating is configured to reduce an immunological response to the implantable neurostimulator when the neurostimulator is implanted in biological tissue.
3. The implantable neurostimulator of claim 1 , where the biocompatible coating is configured to protect the implantable neurostimulator from exposure to biological tissue.
4. The implantable neurostimulator of claim 1 , where the biocompatible coating is configured to protect biological tissue from the implantable neurostimulator.
5. The implantable neurostimulator of claim 1 , where the biocompatible coating is configured to enable efficient acoustic power transfer from biological tissue to the first piezoelectric material.
6. The implantable neurostimulator of claim 5 , where the biocompatible coating is effectively transparent to ultrasound.
7. The implantable neurostimulator of claim 5 , where the biocompatible coating is loaded with an additive.
8. The implantable neurostimulator of claim 7 , where the additive is tungsten.
9. The implantable neurostimulator of claim 5 , where an acoustic impedance of the biocompatible coating is matched with an acoustic impedance of the first piezoelectric material.
10. The implantable neurostimulator of claim 9 , where the thickness of the biocompatible coating is approximately one quarter of the wavelength of a pressure wave that can be used to stimulate the first piezoelectric material.