Photo-Crosslinkable, Insulating Silk Fibroin for Bioelectronics with Enhanced Cell Affinity

Bioelectronic scaffolds that support devices while promoting tissue integration could enable tissue hybrids with augmented electronic capabilities. Here, we demonstrate a Photo-crosslinkable Silk Fibroin (PSF) derivative and investigate its structural, electrical and chemical properties. Lithographically-defined PSF films offered tunable thickness and <1 μm spatial resolution, and could be released from a relief layer yielding freestanding scaffolds with cm-scale uniformity. These constructs were electrically insulating; multi-electrode arrays with PSF-passivated interconnects provided stable electrophysiological readouts from HL-1 cardiac model cells, brain slices and hearts. Compared to SU8, a ubiquitous biomaterial, PSF exhibited superior affinity toward neurons which we attribute to its favorable surface charge and enhanced attachment of poly-d-lysine adhesion factors. This finding is of significant importance in bioelectronics, where tight junctions between devices and cell membranes are necessary for electronic communication. Collectively, our findings are generalizable to a variety of geometries, devices and tissues, establishing PSF as a promising bioelectronic platform.