Biocompatible, ionic-strength-sensitive, double-network hydrogel based on chitosan and an oligo(trimethylene carbonate)-poly(ethylene glycol)-oligo(trimethylene carbonate) triblock copolymer

A double-network (DN) hydrogel was prepared through the sequential photopolymerization of oligo(trimethylene carbonate) (TPT)-block-poly(ethylene glycol)-block-oligo(trimethylene carbonate) diarylate and methacrylated chitosan (CS–MA). The swelling behavior and mechanical properties of the hydrogels were tunable via the control of the concentration of CS–MA. Under physiological conditions, the fracture stress of the DN hydrogel reached 3.4 MPa; this was more than twice that of the corresponding TPT-block-poly(ethylene glycol)-block-TPT single network (1.6 MPa). At high ionic strength, the fracture stress of the DN hydrogel reached 6.4 MPa. The DN hydrogel exhibited good cytocompatibility, as revealed by a live–dead assay. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42459.