Antibacterial and Antifouling Hybrid Ionic-Covalent Hydrogels with Tunable Mechanical Properties.

Because of their self-recovery ability and fatigue resistance, double-network (DN) hydrogels with hybrid ionical-covalent cross-linking have received wide attention. In this work, by a simple "one-pot" method, a novel kind of hybrid ionic-covalent chitosan/poly(sulfobetaine methacrylate) (CS/PSBMA) DN hydrogels was prepared. The hydrogels showed high tensile strength (2.0 MPa), strong elastic modulus (0.5 MPa), fast self-recovery ability as well as excellent fatigue resistance, high mechanical strength, and toughness retention rate after soaking in water for 24 h. Additionally, the mechanical properties of the DN gels were enhanced after stretch and relaxation because of the rearrangement of the CS network. More excitingly, because of the antifouling feature of PSBMA and the inherent antibacterial property of CS, the hybrid DN hydrogels demonstrated a "repel and kill" effect on microorganisms. The CS/PSBMA DN hydrogels may find potential applications in biomedical fields, such as artificial connective tissues, implantable devices, and wound dressing.