Design of metal-phenolic network (MPN)-loaded sodium alginate hydrogels as potential wound dressing candidates: Photothermal antibacterial investigation and application

TFe@SC hydrogel forms via tannin-Fe 3+ and Ca 2+ crosslinked alginate-chitosan network. • Tannin-Fe 3+ complex grants the hydrogel stable 808 nm photothermal performance. • Amino and catechol groups trap bacteria through electrostatic & hydrogen bonds. • Laser-triggered TFe@SC hydrogel achieves >87% activity against two typical bacteria. • TFe@SC dressing cures infected wounds, eases inflammation with good biocompatibility. Antibiotics overuse frequently leads to bacterial resistance. A number of innovative approaches are being developed for bacteria inhibition. Fabrication of a biocompatible, easily prepared antibacterial dressings is highly desirable for promoting infected wound healing. In this work, a photothermal antibacterial dressing (TFe@SC) was constructed based on a natural polyphenolic molecule tannic acid, sodium alginate (SA) and chitosan (CHI). Tannic acid chelated with iron ion to form a tannin‑iron ion TA-Fe 3+ coordination complex (TFe), which have photothermal properties. Furthermore, TFe was integrated into the sodium alginate (SA)-Ca 2+ -chitosan (CHI) composite hydrogel (SC hydrogel). The amino and carboxyl groups of SC hydrogel and phenolic hydroxyl groups of TFe generate hydrogen bonding interactions, enabling TFe to be firmly incorporated into the interior structure of SC hydrogel. TFe@SC hydrogel possesses some properties of antimicrobial dressings, such as high biosafety, adhesion to bacteria, and inhibition of bacterial proliferation with photothermal therapy (PTT). Meanwhile, the TFe@SC hydrogel was constituted by a variety of natural biomass molecules, including tannins, sodium alginate and chitosan, which endow the hydrogel with biocompatibility. Fe@SC hydrogel is a facile and easily synthesized composite material, which holds great promise for application as a functional hydrogel dressing.