Photocrosslinked Silk Fibroin Cryogels for Engineering Complex Multilayered Materials

Capturing the intricate zonal morphology of human tissues, such as skeletal and cardiac muscle, valves, and the osteochondral interface, is crucial in tissue engineering and regenerative medicine. Current techniques to manufacture multizonal constructs compatible with various materials, featuring appropriate porosity and pore arrangement for cellular ingrowth and remodeling, and tunable mechanical properties, remain inadequate. We present a novel, scalable technique for assembling material building blocks with distinct properties into a multizonal construct. This technique utilizes photo‐initiated crosslinking via di‐tyrosine bond formation, with building blocks crosslinked and assembled in their frozen state. Subsequent thawing or freeze‐drying results in materials with microscale porosity and tunable pore size, shape, and alignment. Demonstrated using silk fibroin and gelatin, this method is applicable to other tyrosine or tyramine‐containing materials. This is the first demonstration of silk cryogels made using the photocrosslinking approach, resulting in larger and more stable pores than their physically crosslinked counterparts. Importantly, the method is cytocompatible and supports covalent immobilization of bioactive molecules for easy biofunctionalization. This platform approach provides a versatile and scalable technique for creating mechanically robust biomimetic scaffolds with broad applications in tissue engineering, particularly in aligned structures.