In Situ Construction of High Strength Chitosan/Polydopamine Hydrogel in Alkali System with Potential Radical Scavenging and Bacterial Inhibition

Herein, a novel chitosan-polydopamine hydrogel was constructed through the in situ self-polymerization of dopamine in a chitosan/alkali aqueous solution. Solid-state 13C NMR, FTIR, and SEM confirmed that the formed polydopamine (PDA) particles easily wrapped on chitosan chains to fabricate homogeneous porous hydrogels with pearl-like PDA-chitosan nanofibrils. Thus, the hybrid hydrogels exhibited homogeneous architecture with a high compressive strength of 0.43 MPa. At elevated dopamine (DA) content, the size of PDA particles gradually enlarged from 14 to 32 nm, and a denser network structure was formed because chitosan and DA were partially crosslinked by epichlorohydrin (ECH). Furthermore, PDA endowed the hybrid hydrogels with excellent drug-loading capacity, radical scavenging, and antibacterial activities, which displayed great potential for biomedical and therapeutic applications. Therefore, we provide a new avenue for the creation of polymeric hybrid biomaterials from an alkali aqueous solution.