Hofmeister Effect-Assisted Strong Natural Biopolymer-Based Hydrogels with Multi-Functions

Main observation and conclusion Natural biopolymer-based hydrogels have been extensively studied in recent years due to their excellent biocompatibility. However, the preparation of multi-functional and tough natural biopolymer-based hydrogels is still a challenging problem. Herein, a natural biopolymer-based hydrogel is prepared using gelatin and carboxymethyl chitosan (CMCS) through a one-step soaking method. The prepared hydrogel without any synthetic polymers and crosslinking agents has a fully physical crosslinking structure. Due to the hydrophobic interaction brought by the Hofmeister effect, the mechanical properties of soaked hydrogels (tensile stress and strain can reach 3.77 MPa and 1082%) are superior to conventional protein hydrogels. In addition, the prepared gelatin/carboxymethyl chitosan (Gel/CMCS) hydrogels exhibit a variety of appealing properties, including good shape memory, fatigue resistance, electrical conductivity, water retention, drug releasing, antibacterial property, and recyclability. This strategy opens up a new horizon to fabricate hydrogels with excellent mechanical properties and multiple functions, which can extend their applications in the biomedicine area and other related fields.