SU8-Based Micro Neural Probe for Enhanced Chronic in-Vivo Recording of Spike Signals from Regenerated Axons

In this paper, a fully biocompatible and flexible micro neural probe based on SU-8 to record neural spike signals from regenerated axons from amputated peripheral nerves is presented. The channel structures were designed at the tip of the probe to capture a single axon and guide its growth to ensure good quality contact between the single axon and the gold micro electrode. The gold electrodes placed at the bottom of the channel structures were exposed to allow contact with axons. The test results of in-vitro cytotoxicity tests showed that the SU-8 microprobe is biocompatible. Dorsal root ganglion (DRG) was used to evaluate neuronal cell adhesion to the microelectrodes. The probe was assembled into a fully biodegradable biosynthetic nerve regeneration guide (BNRG) filled with nerve growth factor (NGF) that promotes regeneration of specific sensory or motor axons. Neural spike signals from regenerated axons from amputated peripheral nerves were chronically recorded (> 6 months) without any sign of tissue damage.