Conductive Antibacterial Silk Sutures for Combating Surgical Site Infections via Electrically Controlled Drug Release

Current antibacterial sutures for preventing surgical site infections (SSIs) face challenges including suboptimal drug utilization efficiency and uncontrolled burst release. To address these limitations, an antibacterial conductive suture with an electrically controlled drug release system is developed in this study. Polypyrrole (PPy) doped with tannic acid (TA) is in situ polymerized on the surface of silk sutures precoated with chitosan/gelatin (CS/GE), designated as PCG-SS. The PCG-SS exhibits excellent conductivity, enabling voltage-dependent regulation of TA release. At -0.6 V applied potential, PPy underwent electrochemical reduction with decreased positive charge density, enabling maximal TA release; conversely, at +0.4 V, PPy attained an oxidized state with enhanced positive charges, strengthening electrostatic adsorption of anionic TA and achieving 80% suppression of drug elution. Under -0.6 V stimulation, the antibacterial rates of PCG-SS against S. aureus and E. coli exceeded 90%. This work successfully validated that a PPy-based drug-controlled release system can effectively formulate drug release programs, providing new insights into the study of electronically controlled drug delivery systems.