Photo-Crosslinked Silk Fibroin for 3D Printing

Abstract

Silk fibroin in material formats provides robust mechanical properties, and thus is a promising protein for 3D printing inks for a range of applications, including tissue engineering, bioelectronics, and bio-optics. Among the various crosslinking mechanisms, photo-crosslinking is particularly useful for 3D printing with silk fibroin inks due to the rapid kinetics, tunable crosslinking dynamics, light-assisted shape control, and the option to use visible light as a biocompatible processing condition. Multiple photo-crosslinking approaches have been applied to native or chemically modified silk fibroin, including photo-oxidation and free radical methacrylate polymerization. The molecular characteristics of silk fibroin, i.e., conformational polymorphism, provide a unique method for crosslinking and microfabrication via light. The molecular design features of silk fibroin inks and the exploitation of photo-crosslinking mechanisms suggest the exciting potential for meeting many biomedical needs in the future.

Extreme Biomimetics: Designing of the First Nanostructured 3D Spongin–Atacamite Composite and its Application

“…Although proteins are particularly appealing to formulate inks for 3D printing, [ 55 ] spongin remains to be an exceptional case. In contrast to collagen, [ 56,57 ] silk, [ 58,59 ] or keratin, [ 60 ] 3D printing of spongin at this moment is only hypothetical. The main change in this development is the non‐homogenous chemical composition of spongin, which does not rely on an individual, chemically pure, structural protein.…”

Biomedical applications of silkworm ( Bombyx Mori ) proteins in regenerative medicine (a narrative review)

“…Silk materials are rather like the actual indisputable fact that SF could even be a biocompatible natural protein, that enables, minimal reaction, good adherence, and cell growth on/in silk matrices (Farokhi et al, 2018). Silk fibroin protein ink formulations have emerged as an honest candidate for bio-ink applications because it already contains a number of unique properties to meet the requirement for in vitro bio-ink (Agostinacchio et al, 2020;Mu, Sahoo, et al, 2020). Such as printability (Mu, Fitzpatrick, & Kaplan, 2020;Wlodarczyk-Biegun & Del Campo, 2017), low immunogenicity, non-cytotoxicity, high durability, controllable porosity, and biocompatibility (Farokhi et al, 2020).…”

Conformation-driven strategy for resilient and functional protein materials

“…Notably, several protein hydrogels exhibited conformational changes after cross-linking, such as enzyme–cross-linked silk fibroin elastomers ( 19 ). The improvement in the current work may be attributed to the short cross-linking time of the Ru(II)/persulfate approach (2 to 3 min) compared with that of the enzymatic approach (30 to 60 min); short cross-linking time minimizes the disturbance to the initial conformation ( 39 , 40 ). The random coil–dominated conformation is a prerequisite for the entropy elasticity of protein hydrogels.…”

“…We cross-linked regenerated silk fibroin in solution to form hydrogels via a ruthenium [Ru(II)]/persulfate–mediated approach that is based on the photo-oxidation and coupling of tyrosine residues ( 39 – 41 ) ( Fig. 1 C ).…”