Multi-strategy synergistic scheme for progressive construction and optimization of non-covalent all-polysaccharide double-network hydrogels

To reduce the use of synthetic polymers and avoid the potential risk of chemical cross-linking, this work proposes a multi-strategy synergistic scheme for the progressive construction and optimization of non-covalently interacting chitosan (CHI)/alginate (ALG) (CA) all-polysaccharide double-network (DN) hydrogels. The hydrogen-bonding solubilization strategy effectively avoided the generation of CHI-ALG polyelectrolyte complexes and endowed the CA solution with heat-induced gelation properties. Relatedly, the heat-induced selectivity promotes CHI self-crosslinking via hydrogen bonding to produce phase separation, ensuring the construction of the first network of CHI in CA DN hydrogels. Importantly, ALG formed ALG aggregates under CHI first network restriction and poor solvent induction, which enhanced the mechanical properties of CA hydrogels by 728.30 %. Moreover, the double-ion cross-linking ensures the stabilization of ALG aggregates and constructs the ALG second network in CA hydrogels. Notably, the CA DN hydrogels show greater than 90 % antibacterial activity for Staphylococcus aureus and Escherichia coli which can effectively prevent the CA DN hydrogels from being contaminated by bacteria in preparation and practical application. The excellent comprehensive properties of CA DN hydrogels constructed in this work make them promising materials, and the multi-strategy synergistic scheme provides new ideas for the construction and optimization of all-polysaccharide DN hydrogels.