Hydrogen-Bond Cross-Linking between Chitosan and Urethane-Modified Polycaprolactone: Influence of PCL Structure on Cryogel Properties

Cryogels are macroporous biomaterials that exhibit shape recovery, making them attractive for various applications. Here, we report a simple method for fabricating a chitosan-based cryogel by modifying polycaprolactone with a urethane linkage (PCLU) and mixing it with a chitosan solution. The network structure was formed via hydrogen bond cross-linking. The effect of PCLU structures, such as star-shaped (stPCLU) and linear (LPCLU), on the physical properties of chitosan-based cryogels (CstU and CLU) was investigated. The CstU provided a large pore size and a high swelling degree due to the arm structure of stPCLU, which restricted chain mobility and alignment. In the case of CLU, the linear structure of LPCLU facilitated chain alignment and high crystallinity, resulting in high compressive strength and small pore size. Moreover, the synergistic effect of PCLU content and hydrogen bond cross-linking provided high compressive strength and rheological properties. In addition, biocompatibility testing showed that CstU and CLU are nontoxic to cells and promote cell adherence on their surfaces. Therefore, CstU and CLU have the potential for development in biomedical applications.