Drug-Free Ultrasound-Responsive Mechanoluminescent Suture Enables On-Demand Antibacterial Therapy and Enhanced...

Conventional antibacterial sutures commonly rely on antibiotic loading, which may be associated with concerns regarding drug resistance and biocompatibility. To address this challenge, this study developed a drug-free, ultrasound-responsive mechanoluminescent suture. By incorporating SrAl₂O₄:Eu^{2 +}, Dy^{3 +} (SAOED) into poly-ε-caprolactone (PCL) fibers, PCL/SAOED (PS) sutures were fabricated. Upon ultrasound irradiation, the PS sutures generated reactive oxygen species (ROS) in situ, likely through a mechanoluminescence-mediated process, resulting in antibacterial activity against Escherichia coli and Staphylococcus aureus without the use of exogenous antimicrobial agents, with PS10 achieving approximately 75% and 79% reduction against the two strains, respectively, while PS20 exceeded 80% in preliminary tests. In vitro experiments indicated that PS sutures exhibited acceptable biocompatibility and measurable ROS-scavenging capacity. In a rat full-thickness skin defect model, ultrasound-activated PS sutures were associated with improved healing outcomes in both infected and non-infected wounds, with suggestive evidence of antibacterial, anti-inflammatory, and pro-angiogenic effects. Overall, this study presents a preliminary strategy that may inform the development of drug-free, ultrasound-responsive, on-demand antibacterial smart sutures, pending further mechanistic and preclinical validation.