Construction of a\nMultifunctional Janus Nanofiber\nMembrane Based on Tannic Acid–Fe Complexes for Photothermal/Drug\nSynergistic Antibacteria

Persistent\ninfections caused by bacterial contamination\nand excess\nexudate often delay wound healing. To address this challenge, we have\ndeveloped a multifunctional antibacterial Janus nanofibrous membrane\nwith unidirectional fluid transport, pH-triggered drug release, and\nphotothermal effect as a potential candidate for the infected wounds\nusing electrospinning technology. This Janus membrane comprises a\ndual-layer structure: a hydrophilic poly(ε-caprolactone)/tannic\nacid-ferric ion (PCL/TA-Fe<sup>3+</sup>) nanofiber layer that provides\npH-responsive drug release and photothermal antibacterial activity,\nand a hydrophobic PCL nanofiber layer for effective unidirectional\nfluid transport. The dual-gradient Janus structure, designed with\nhierarchical pore sizes and hydrophilic performance, facilitates rapid\nwater transport. Meanwhile, due to the introduction of TA-Fe<sup>3+</sup> complexes in situ, the Janus membrane demonstrates the capacity\nfor controlled release of TA based on the pH level along with excellent\nphotothermal properties. The synergistic action of TA-controlled release\nand photothermal effect endows the Janus membrane with nearly 100%\nbacterial eradication against Staphylococcus aureus and Escherichia coli as well as the\neradication ability of the biofilm. Furthermore, the Janus membrane\nexhibits acceptable water absorption, moisture permeability, mechanical\nstrength, and biocompatibility, indicating its potential as an optimal\ncandidate for treating infected wounds.