An organic hydrogel with high-strength, high-water retention properties for pressure sore protection

The excellent mechanical properties and high-water retention of hydrogels will expand the application in the field of biomedical materials. In this work, we prepared hydrogel based on methacryloyl gelatin (GelMA), sulfobetaine and quaternized chitosan (QCS) by “one-pot” method. GelMA acts as cross-linking agent to cross-link the PSBMA network. QCS chains are interspersed in the PSBMA network. The hydrogel obtained after the polymerization initiated by ultraviolet light is further immersed in glycerin for solvent replacement. The hydrogel exhibits excellent mechanical properties with a breaking stress of 4.73 MPa and a breaking strain of 160%. After 100 successive loading–unloading cycles, the hydrogel remains intact and the maximum load decreases slightly. In addition, the hydrogel has excellent antifreeze properties and remains flexible and transparent after being placed at − 20 °C for three days. Antibacterial experiments proved that hydrogel could effectively resist the adhesion of E. coli. In the trypsin solution, the hydrogel will be degraded, and the degradation rate can be regulated by trypsin concentration. The hydrogel also has good water retention and biocompatibility and is expected to be used in biological tissue replacement and medical devices.