Photo–cross-linkable, insulating silk fibroin for bioelectronics with enhanced cell affinity

Abstract

<jats:p>Bioelectronic scaffolds that support devices while promoting tissue integration could enable tissue hybrids with augmented electronic capabilities. Here, we demonstrate a photo–cross-linkable silk fibroin (PSF) derivative and investigate its structural, electrical, and chemical properties. Lithographically defined PSF films offered tunable thickness and &lt;1-µm spatial resolution and could be released from a relief layer yielding freestanding scaffolds with centimeter-scale uniformity. These constructs were electrically insulating; multielectrode 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-<jats:sc>d</jats:sc>-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.</jats:p>

Photo-Crosslinked Silk Fibroin for 3D Printing

“…However, GMA is reported to react with other groups, such as hydroxyl and carboxyl, via both the transesterification and the epoxide ring-opening mechanisms [ 102 , 104 ] ( Figure 5 b). For silk fibroin heavy chains, the amino acid residues with hydroxyl and carboxyl groups have a higher molar ratio (around 19.4%) than those with amine groups (lysine, 0.2%) [ 105 , 106 , 107 ]. Thus, methacryloyl substitution at the hydroxyl and carboxyl groups may increase the number of cross-linkable sites and thus the photo-crosslinking density of silk fibroin.…”

Click Decoration of Bombyx mori Silk Fibroin for Cell Adhesion Control

“…Several previous works reported the achievement of cell patterning using silk fibroin as a substrate based on conventional photolithographic methods [ 22 , 23 , 24 ]. These works achieved excellently precise patterning of silk fibroin itself.…”

Transparent and Conformal Microcoil Arrays for Spatially Selective Neuronal Activation

“…While the use of bioinert materials like SU-8 for chronic neural implants has been demonstrated to mitigate the adverse inflammatory responses that are usually associated with metal electrodes (Zhou et al, 2017; Yang et al, 2019), we have developed a general platform that may be extended to other bioactive materials (e.g silk) which could further minimize or eliminate tissue fibrosis. The use of photo-cross-linkable silk fibroin has been shown to exhibit greater affinity to cultured neurons than SU-8 in addition to being a comparable insulation material (Ju et al, 2020). In addition, electrodes with silk-based coatings and supports have demonstrated significantly reduced glial responses in both in-vitro and in-vivo applications (Tien et al, 2013; Lee et al, 2019).…”