Spirally Arrayed Electrode for Spatially Selective and Minimally Displacive Peripheral Nerve Interface

The peripheral neural interface (PNI) is a vital technology in robotic prosthesis due to its potential to provide bidirectional communication between the prosthesis and the brain. However, a more efficient trade-off between neural spatial selectivity and invasiveness is still needed. We propose a 32-channel spirally arrayed electrode (SPAE) that achieves high spatial selectivity for the axons in the nerve while minimizing the potential nerve damage. SPAE has an array of probes with multiple electrodes per probe, which reduces the amount of nerve tissue damaged per electrode. This array is spirally inserted into the peripheral nerve, which enables even electrtode distribution and may prevent the constriction of the nerve. The SPAE has an average electrode impedance of 296 k Omega with a standard deviation of 52 k Omega at 1000 Hz. The SPAE was acutely implanted into the rat sciatic nerve and was able to obtain spontaneous neural signals. The proposed SPAE design could lead to a PNI platform with low invasiveness while achieving high spatial selectivity with the nerve. We believe, with further experimentations and design optimizations, the SPAE could be a promising and beneficial platform to further the study into the peripheral nervous system and the development of robotic prosthesis and its control.