Electrowriting of silk fibroin: Towards 3D fabrication for tissue engineering applications

Electrowriting (EW) successfully combines the principles of two widely studied biofabrication techniques; 3D printing and electrospinning, and is capable of producing complex architectures, with submicron resolutions. However, the EW process so far is limited mainly to thermoplastic polymers of synthetic origin such as poly ε-caprolactone. Herein we demonstrate the EW of silk fibroin (SF) on an in-house build setup to identify the compatibility of water-based SF ink with EW. More specifically, we optimized the SF ink composition and investigated the effect of EW process parameters including ink concentration, collector translation speed, applied voltage, and distance between nozzle and collector on filament orientation and diameter. During SF ink preparation, control over the silk degumming process and ink concentration enabled modulation of rheology and surface tension properties of SF inks. We envision that the EW of hydrophilic SF will offer a new class of material structures with biological properties akin to natural systems.