Photocrosslinkable and self-healable hydrogels of chitosan and hyaluronic acid

Biocompatible and biodegradable hydrogels with biomimetic properties, such as self-repairing, are increasingly interesting for biomedical applications, particularly when they can be printed or in situ formed to mimic extracellular matrix or as personalized implantable devices in tissue regeneration or drug delivery. Photocrosslinkable hydrogels based on methacrylated chitosan (CHIMe) and hyaluronic acid that exhibit according with their composition, tuneable physico-chemical properties are here presented. The study of the conversion, gelation time, mechanical and rheological properties of photopolymerized CHIMe showed an optimal phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) initiator feed (0.1 % w). These photocrosslinkable hydrogels demonstrated being able to promote doubly crosslinked hydrogels with similar Young Moduli regardless the cycles of self-healing processes, and tailored swelling (25-70 swelling factor), mechanical (1 × 10-4-2 × 10-2 MPa) and rheological properties, as a function of polysaccharides relative content. Clear evidences have been found that fast photopolymerization of CHIMe/HA solutions leads to biocompatible (>80 % cell viability), biodegradable (20-24 days in hydrolytic medium) and robust self-healable hydrogels suitable for advanced biomedical and tissue engineering applications.