Long-Lived, Transferred Crystalline Silicon Carbide Nanomembranes for Implantable Flexible Electronics.

Abstract

Implantable electronics are of great interest owing to their capability for real-time and continuous cellular-electrical-activity recording. Nevertheless, since such systems involve direct interfaces with surrounding biofluidic environments, maintaining their long-term sustainable operation, without leakage currents or corrosion, is a daunting challenge. Herein, we present a thin, flexible semiconducting material system that offers attractive attributes in this context. The material consists of crystalline cubic silicon carbide nanomembranes grown on silicon wafers, released and then physically transferred to a final device substrate (e.g. polyimide). The experimental results demonstrate that SiC nanomembranes with thicknesses of 230 nm do not experience the hydrolysis process (i.e. the etching rate is 0 nm/day at 96ºC in PBS). There is no observable water permeability for at least 60 days in PBS 96ºC, and non-Na+ ion diffusion detected at a thickness of 50 nm after being soaked in 1X-PBS for 12 days. These properties enable Faradaic interfaces between active electronics and biological tissues, as well as multimodal sensing of temperature, strain and other properties without the need for additional encapsulating layers. These findings create important opportunities for use of flexible, wide band gap materials as essential components of long-lived neurological and cardiac electrophysiological device interfaces.