Cryoprinting of nanoparticle-enhanced injectable hydrogel with shape-memory properties

Abstract

Cryogels with interconnected macropores for cell seeding and shape-memory properties for non-invasion injection have shown great potential in tissue engineering. However, traditional manufacturing methods of cryogels are time-consuming and labor-intensive, which has limitations in rapidly fabricating customized cryogels. In this work, we developed a cryoprinting platform that combined 3D printing and cryogelation technologies to fabricate nanoparticle-enhanced injectable and shape-memory cryogels. After cryoprinting, the silk fibroin-based cryogels could be printed to a variety of shapes and sizes and allow rapid volumetric recovery after injection through a needle. These cryogels encapsulating laponite nanoparticles provided enhanced proliferation, spreading, and osteogenic differentiation of the seeded bone marrow-derived mesenchymal stem cells (BMSCs). In addition, the integration of implanted hydrogels with host tissues and the cell invasion within the hydrogel was found with no obvious inflammatory response after subcutaneous injection. These findings showed that the printed nanoparticle-enhanced cryogels could promote the seeded stem cells to actively participate in bone regeneration. In short, this work not only offered a feasible and effective platform to print customized cryogels, but also provided an injectable cryogel for bone tissue engineering via this advanced printing platform.

Keywords

• Cryoprinting
• Shape-memory
• Injectable
• Osteogenic differentiation