Preparation of Autoclavable and Injectable Silk Fibroin Cryogels for Tissue Engineering Applications

A cryogel is a supermacroporous gel network that is generated at subzero temperatures by polymerizing monomers or gelating polymeric precursors. Since cryogels possess inherent characteristics such as interconnected macroporous structures, excellent mechanical properties, and high resistance to autoclave sterilization, they are highly desirable for tissue engineering and regenerative medicine. Silk fibroin, a natural protein obtained from Bombyx mori silkworms, is an excellent raw material for cryogel preparation. The aim of this study is to establish a controlled method for preparing silk fibroin cryogels with suitable properties for application as tissue engineering scaffolds. Using a dual crosslinking strategy consisting of low-temperature radical polymerization coupled with methanol-induced conformational transformation, porous cryogels are prepared. The cryogels display many unique characteristics, such as an interconnected macroporous structure, a high water absorption capacity, water-triggered shape memory, syringe injectability, and strong resilience to autoclave sterilization. Furthermore, the cryogels demonstrate excellent biocompatibility and cell affinity, facilitating cell adhesion, migration, and proliferation. The interconnected supermacroporous architecture resembling the native extracellular matrix, together with their unique physical properties and autoclaving stability, suggests that cryogels are promising candidate scaffolds for tissue engineering and cell therapy.