Bioelectronic device design for recording from dispersed areas of the nervous system

Recent advances in bioelectronic materials and thin-film fabrication methods have enabled high-fidelity access to the nervous system. However, large regions of the peripheral nervous system remain inaccessible due to its extensive and fractal nature, shifting from large diameter nerve bundles to increasingly smaller formats, including nerve fibers, neuromuscular junctions, and nerve plexi. Current implantable neural interfaces are typically designed to access these proximal regions of the nervous system, often fabricated as conformable microelectrode arrays, designed to sit on the surface of the nervous sub-structure, e.g. the spinal cord, sciatic nerve, or the cortex of the brain. These formats are incompatible with the distal regions of the nervous system, leaving the information that originates there inaccessible. Here, we discuss strategies for designing and placing thin-film implants inside of tissues to maintain access to local bioelectrical elements.