Ultrathin κ-Carrageenan/Chitosan Hydrogel Films with High Toughness and Antiadhesion Property

Designing tough biopolymer-based hydrogels as structural biomaterials has both scientific and practical significances. We report a facile approach to prepare polysaccharide-based hydrogel films with remarkable mechanical performances and antiadhesion property. The hydrogel films with a thickness of 40-60 μm were prepared by mixing aqueous solutions of κ-carrageenan (κ-CG) and protonated chitosan (CS), evaporating the solvent, and then swelling the casted film in water to achieve the equilibrium state. The obtained κ-CG/CS gel films with a water content of 48-88 wt % possessed excellent mechanical properties with a breaking stress of 2-6.7 MPa and a breaking strain of 80-120%, superior to the most existing biopolymer-based hydrogels. The extraordinary mechanical properties of gel films obtained over a wide range of mass ratio of κ-CG to CS should be rooted in the synergistic effect of ionic and hydrogen bonds between the κ-CG and CS molecules. In addition, the tough gel films showed good self-recovery ability, biocompatibility, and cell antiadhesion property, making them promising as an artificial dura mater and diaphragm materials in the surgery. The design principle by incorporating multiple noncovalent bonds to toughen the biopolymer-based hydrogels should be applicable to other systems toward structural biomaterials with versatile properties.