Photo-responsive Carboxymethyl Chitosan/Laponite Hydrogel as a Potential Spinal Cord Injury Scaffold: Characterization and Cytocompatibility Study

We synthesized photo-responsive carboxymethyl chitosan (CMC-MA) via free radical polymerization and utilized nanoclay laponite (LAP) as an inorganic crosslinking agent to develop an injectable and 3D-printable CMC-MA/LAP hydrogel. We determined the optimal ratio of 2.5 w/v% CMC-MA/7.5 w/v% LAP based on injection molding, compression modulus, swelling properties, rheological properties, and 3D printing properties of the hydrogel system. In-vitro cytocompatibility experiments showed that both CMC-MA and CMC-MA/LAP hydrogel had no inhibitory effect on cell proliferation and can promote cell growth when cultured on the surface of the hydrogel matrix. Moreover, the hydrogel containing LAP particles significantly facilitated cell adhesion (>60%) compared with the hydrogel without LAP (20%). Our findings demonstrate that the CMC-MA/LAP hydrogel has great potential for tissue repair in neural tissue engineering.