Photo- and Schiff Base-Crosslinkable Chitosan/Oxidized Glucomannan Composite Hydrogel for 3D Bioprinting

Chitosan is an attractive material for developing inks for extrusion-based bioprinting of 3D structures owing to its excellent properties, including its mechanical properties and antimicrobial activity when used in wound dressings. A key challenge in formulating chitosan-based inks is to improve its gelation property to ensure reliable printing and the mechanical stability of the printed structures. To address these challenges, this article presents a novel chitosan/oxidized glucomannan composite hydrogel obtained through the combination of Schiff base and phenol crosslinking reactions. The proposed biomaterial forms soft hydrogels through Schiff base crosslinking, which can be further stabilized via visible light-induced phenol crosslinking. This dual-crosslinking approach enhances the printability and robustness of chitosan-based ink materials. The proposed chitosan/oxidized glucomannan hydrogel exhibits excellent extrudability and improved shape retention after extrusion, along with antimicrobial properties against Escherichia coli. Moreover, good cytocompatibility was confirmed in animal cell studies using mouse fibroblast 10T1/2 cells. These favorable features make this hydrogel highly promising for the extrusion-based bioprinting of complex 3D structures, such as tubes and nose-like structures, at a low crosslinker concentration and can expand the prospects of chitosan in bioprinting, providing a safer and more efficient alternative for tissue engineering and other biomedical applications.