Photothermal and antimicrobial properties of catechol-chitosan silver nanoparticles/esterified sodium alginate composite hydrogels

This study focuses on the preparation and evaluation of a catechol-modified hydroxypropyl chitosan/silver nanoparticle/phenylboronic acid alginate composite hydrogel (C/S/A/P/P). Hydroxypropyl chitosan (HCS) was modified with 3,4-dihydroxybenzaldehyde (DBA) via Schiff base reaction to produce adhesive catechol-modified hydroxypropyl chitosan (CHCS). The mechanical properties and self-healing ability of the hydrogel were enhanced by grafting phenylboronic acid (PBA) onto sodium alginate (SA) to form SA-PBA. The incorporation of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) further improved the mechanical properties, water absorption, and moisture retention of the hydrogel. Silver ions were reduced to silver nanoparticles (AgNPs) by the reducing property of catechol and integrated into the hydrogel network, endowing it with antibacterial functionality. The C/S/A/P/P hydrogel exhibits excellent mechanical properties (tensile stress of 391.99 kPa and strain of 149.11%), photothermal properties, and antibacterial performance (inhibition rates of 95.1% against Escherichia coli and 64.3% against Staphylococcus aureus). This green preparation method offers a new approach for developing advanced wound dressings.