Zinc Alginate/Polydopamine/Zinc Oxide Fibers: A Photothermally Responsive Antimicrobial Wound Dressing

Graphical The Alg/PDA/ZnO solution was used to form photothermal responsive antibacterial fibers under Zn2+ displacement by a wet spinning process. Traditional medical materials, such as gauze are limited in their application for complex wound healing due to insufficient antibacterial properties, thereby emphasizing the need to develop fiber materials with intelligent, controllable antibacterial functions. In this work, zinc oxide (ZnO) and polydopamine (PDA) were synthesized in situ within sodium alginate (Alg) solutions. The solutions mixed in specific proportions were used as a spinning solution to produce composite fibers with photothermal response characteristics, efficient and prolonged antibacterial activity, and good biocompatibility through a wet spinning process. Benefit from the in situ synthesis of ZnO and the Schiff base reaction between zinc alginate (Alg-Zn) and PDA, the tensile strength of the composite fibers reached up to 26.5 ± 2 MPa. The introduction of PDA endowed the composite fibers with excellent photothermal properties, allowing them to rapidly heat to 70 °C and remain stable under light irradiation. Antibacterial tests against Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa showed maximum inhibition zones of 7 mm, 10 mm, and 4 mm, respectively, primarily attributable to the synergistic antibacterial effects among Alg-Zn, PDA, and ZnO. The excellent photothermal response and antibacterial properties lay a solid foundation for the application of Alg-Zn/PDA/ZnO composite fibers in medical materials.