Thermoformed Parylene-C Cuff Electrodes for Small Nerve Interfacing

Peripheral nerve interfacing plays a crucial role in various healthcare applications. Generally, interfacing peripheral nerves results in a compromise between selectivity and invasiveness. In particular, large nerves carry many axonal fibers, which are difficult to address selectively without penetrating the nerve. Higher selectivity without nerve penetration can be achieved by targeting small nerves with extraneural cuff electrodes. However, in practice, small nerves are challenging to interface appropriately. Herein, a new multielectrode device is presented that can selectively interface small nerves (<200 μm). The device is fabricated using rapid laser-based processing with biocompatible materials such as parylene-C and Pt/Ir alloy. Furthermore, the cuff electrode is prefolded via a stick-and-roll thermoforming process, which simplifies the interfacing procedure. It is shows that the device is capable of selectively stimulating the nerve of a locust in vivo. Moreover, the subjects show no increased mortality 2 weeks after the implantation of the device.