Construction of a Multifunctional Janus Nanofiber Membrane Based on Tannic Acid–Fe Complexes for Photothermal/Drug Synergistic Antibacteria

Persistent infections caused by bacterial contamination and excess exudate often delay wound healing. To address this challenge, we have developed a multifunctional antibacterial Janus nanofibrous membrane with unidirectional fluid transport, pH-triggered drug release, and photothermal effect as a potential candidate for the infected wounds using electrospinning technology. This Janus membrane comprises a dual-layer structure: a hydrophilic poly(ε-caprolactone)/tannic acid-ferric ion (PCL/TA-Fe³⁺) nanofiber layer that provides pH-responsive drug release and photothermal antibacterial activity, and a hydrophobic PCL nanofiber layer for effective unidirectional fluid transport. The dual-gradient Janus structure, designed with hierarchical pore sizes and hydrophilic performance, facilitates rapid water transport. Meanwhile, due to the introduction of TA-Fe³⁺ complexes in situ, the Janus membrane demonstrates the capacity for controlled release of TA based on the pH level along with excellent photothermal properties. The synergistic action of TA-controlled release and photothermal effect endows the Janus membrane with nearly 100% bacterial eradication against Staphylococcus aureus and Escherichia coli as well as the eradication ability of the biofilm. Furthermore, the Janus membrane exhibits acceptable water absorption, moisture permeability, mechanical strength, and biocompatibility, indicating its potential as an optimal candidate for treating infected wounds.