Rapid volumetric bioprinting of pristine protein-based (bio)inks

Volumetric bioprinting (VBP) enables the rapid photopolymerization of 3D constructs by modifying the illumination patterns within a build volume. However, only a few unmodified, pristine protein-based bioinks can be used for VBP, making the resulting (bio)printed volumes sometimes incompatible with further modification steps required for extended applications and thus limiting the wider adoption of VBP. We have recently developed new methods for VBP, in which unmodified protein-based (bio)inks with tyrosine groups, including those based on silk, decellularized extracellular matrix (dECM) and gelatin, can be (bio)printed, in their pristine state, by using the tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate/sodium persulfate photoinitiator system to form sophisticated shapes and architectures. Here, we provide step-by-step instructions to complete the VBP process and include the characterization of these bioinks. After treatment, the volumetrically printed silk sericin constructs show properties including reversible shrinkage and expansion, or shape-memory, whereas the volumetrically printed silk fibroin constructs exhibit broadly tunable mechanical performances ranging from a few hundred pascals to hundreds of megapascals. Both types of silk-based (bio)inks as well as dECM (bio)inks are cytocompatible. We further cover several demonstrations that show the potential uses of volumetrically (bio)printed silk and dECM constructs in clinical and biomedical applications.