Bacteria-Responsive Single and Core-Shell Nanofibrous Membranes Based on Polycaprolactone/Poly(ethylene succinate) for On-Demand Release of Biocides

Traditional antibacterial dressings continuously elute biocides, even if there are no bacteria. This unneeded release can cause cytotoxicity, increase costs, and delay healing. We designed a bacteria-responsive nanofibrous wound dressing, which can be degraded in the presence of bacteria to release antimicrobial agents. A model biocide, benzyl dimethyl tetradecyl ammonium chloride (BTAC), was incorporated into bacteria-degradable polymers [polycaprolactone and poly(ethylene succinate)] in two ways: evenly distributed inside the polymers as single nanofibers and encapsulated in a core surrounded by the same polymers as core-shell nanofibers. Because of bacterial activity (both lipase secretion and acidic pH), degradation of the fibers was facilitated and caused the release of incorporated BTAC. BTAC-loaded single and core-shell nanofibers presented >1 log reduction of both Staphylococcus aureus and Escherichia coli within 2 h. Additionally, the core-shell structure provided a more controlled release of BTAC with prolonged antibacterial properties than single nanofibers. The core-shell nanofibers also exhibited minimal cytotoxicity against human fibroblast cells (>80% viable cells after 24 h contact). These nanofibrous mats have the potential to selectively release antibacterial agents to prevent wound infections without delaying wound healing.