A flexible fish-bone-shaped neural probe strengthened by biodegradable silk coating for enhanced biocompatibility

This paper reports a fish-bone-shaped polyimide neural probe for chronic recording applications. This unique design aims to minimize tissue reaction by having flexible substrate, small dimensions, large separation distance between electrodes and the probe shank, as well as large substrate openings. A biodegradable silk polymer is coated around the polyimide structure to provide temporary mechanical strength during insertion. The time required for the complete degradation of silk can be controlled within the range of 30 minutes to 25 hours by water annealing process. In-vitro insertion of the fabricated silk-coated probe into brain tissue has been successfully demonstrated.