Optimizing of an antibacterial silk suture covered with synergistic antibiotics-loaded thermo-responsive chitosan hydrogel against resistant clinical isolates.

Postoperative wound infections have posed a substantial burden on healthcare systems, contributing to high morbidity and mortality rates. To address this issue, researchers have focused on fabricating antibacterial sutures to prevent post-suturing infections. In this study, we present the design and fabrication of a novel antibacterial suture using silk and chitosan. The silk sutures were coated with a thermo-sensitive chitosan hydrogel containing colistin/meropenem (Col/Mer) at concentrations of 64/128 μg/ml, 128/256 μg/ml, and 256/512 μg/ml. Comprehensive characterizations of the fabricated antibacterial sutures were performed, encompassing scanning electron microscopy, in vitro degradation assay, swelling test, drug release behavior, and mechanical analysis. Additionally, the sutures' interactions with fibroblast cells were assessed to evaluate their cytocompatibility. Antibacterial properties of the sutures were also evaluated against standard and resistant clinical isolates. Furthermore, the biocompatibility of the sutures was examined in vivo. Our results demonstrated that the antibacterial sutures exhibited a uniform structure, around 15 % weight loss within 35 days, and roughly 10 % water absorption within 24 h. The results also displayed around 0.006 % (w/w), 0.012 % (w/w), and 0.023 % (w/w) drug concentration in 3 antibiotics-loaded samples while exhibiting a controlled-release pattern in 7 days. Antibacterial studies revealed a significant inhibitory effect against both standard and extensively drug-resistant strains of Acinetobacter baumannii (A. baumannii), as well as the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Moreover, when employed in vivo, the hydrogel-coated silk sutures demonstrated excellent biocompatibility, with no significant signs of inflammation or immune cell aggregation in histological analysis. In conclusion, our developed antibacterial suture presents promising potential for the prevention of post-suturing infections, making it a compelling candidate for further evaluation and translation into practical clinical applications.