Flexible Neural Interface From Non-Transient Silk Fibroin With Outstanding Conformality, Biocompatibility, and Bioelectric Conductivity

Silk fibroin (SF) with good biocompatibility can enable an efficient and safe implementation of neural interfaces. However, it has been difficult to achieve a robust integration of patterned conducting materials (multichannel electrodes) on flexible SF film substrates due to the absence of some enduring interactions. In this study, a thermo-assisted pattern-transfer technique is demonstrated that can facilely transfer a layer of pre-set poly(3,4-ethylenedioxythiophene) (PEDOT) onto the flexible SF substrate through an interpenetrating network of 2 polymer chains, achieving a desired substrate/conductor intertwined interface with good flexibility (≈33 MPa), conductivity (386 S cm⁻¹) and stability in liquid state over 4 months simultaneously. Importantly, this technique can be combined with ink-jet printing to prepare a multichannel SF-based neural interface for the electrocorticogram (ECoG) recording and inflammation remission in rat models. The SF-based neural interface with satisfied tissue conformability, biocompatibility, and bioelectric conductivity is a promising ECoG acquisition tool, where the demonstrated approach can also be useful to develop other SF-based flexible bioelectronics.