Seung-Kyun Kang1

1, Department of Materials Science and Engineering, Seoul National University, Seoul, , Korea (the Republic of)

Nanoscale thin-film technology has opened an era of soft, flexible and stretchable electronics and has also changed the timescale of dissolution of materials. Silicon nanomembranes of 10-100 nm thickness have dissolution behavior on the order of days to months. This feature lets us construct Si electronics for water-soluble and bioresorbable performance using unusual fabrication processes and combining soft/biodegradable polymers. Here we introduce two representative examples of bioresorbable Si electronic devices useful in monitoring and modulating the nervous system. First, a bioresorbable pressure sensor using piezoresistive Si strain gauge and 3D microstructured diaphragm was demonstrated to provide accurate measurement of intracranial pressure during the incubation period of traumatic injury. Wireless interfaces made of polymer-coated bioresorbable metal strips offer stable and continuous pressure monitoring. In-vivo functional and immunochemical demonstrations in a rat model suggests the potential validation of bioresorbable sensors in the clinical stage. In the other example, bioresorbable wireless electrical stimulator interfacing the peripheral nerve was demonstrated as a therapeutic modulator. An integrated circuit of Si diode, capacitor, and inductor with all-biodegradable metal, semiconductor and dielectric materials generate therapeutic electrical pulses by near-field inductive energy transfer. The accelerated functional recovery of transected nerve with electrical stimulation suggests the capability of bioresorbable stimulator to promote and/or modulate the nervous system in the treatment and rehabilitation stage.