An antibacterial hydrogel with desirable mechanical, self-healing and recyclable properties based on triple-physical crosslinking

Antibacterial hydrogels capable of self-healing when damaged have been developing rapidly in recent years owing to their promising applications in biomedical and relevant fields. Despite great achievements, the acute defects of low mechanical property, limited self-healing ability, potential cytotoxicity, poor recyclability and sophisticated preparation process hinder their further applications. Herein, a facile one-pot strategy is proposed to prepare the hydrogel with antibacterial and non-cytotoxic properties using aluminium(III) ions (Al(3+)s) and carboxymethyl chitosan nanoparticles (CMCS NPs) to crosslink with polyacrylic acid (PAA) chains through triple dynamic non-covalent interactions (coordination, hydrogen and electrostatic interactions). Benefit from the strong triple-crosslinked network and dynamic nature of non-covalent bonds, the PAA-Al3+-CMCS hydrogels exhibit a desirable mechanical property (fracture strength of 190.9 kPa, fracture elongation of 1930%) and selfhealing ability (healing efficiency 92.9% of stress, 98.8% of strain, 25 degrees C, 24 h of healing) which is not obviously disturbed by surface ageing or erosion (e.g. acid, alkali and salt solutions). Besides, owing to the fully physical crosslinking structure, the as-prepared hydrogels are easy to recycle in pollution-free ways. This strategy opens a new avenue to fabricate hydrogels with outstanding mechanical properties and multi-functionality synchronously.