Braided silk sutures coated with photoreduced silver nanoparticles for eradicating Staphylococcus aureus and Streptococcus mutans infections

Background: Infections resulting from surgical procedures and wound closures continue to pose significant challenges in healthcare settings. To address this issue, the investigators have developed antibacterial nonresorbable braided silk sutures using in situ deposited silver nanoparticles (AgNPs) and investigated their efficacy in eradicating Staphylococcus aureus and Streptococcus mutans infections. Methods: The braided silk sutures were modified through a simple and efficient in situ photoreduction method, resulting in the uniform distribution of AgNPs along the suture surface. The synthesized AgNPs were characterized using scanning electron microscopy (SEM), dynamic light scattering analysis (DLS) and Fourier Transform Infrared Spectroscopy analysis (FTIR) confirming their successful integration onto the silk sutures. The antibacterial activity of the nanoparticle coated sutures were compared and evaluated with non-coated braided silk sutures through in vitro assays against both S. aureus and S. mutans. Results: The surface and cross-sectional analysis of the treated sutures revealed a uniform and homogeneous distribution of silver particles achieved through the photoreduction of silver solution. This observation confirms the successful coating of silver nanoparticles (AgNPs) on the sutures. The antimicrobial studies conducted, demonstrated significant reductions in bacterial colonies when exposed to the silver nanoparticle-coated sutures. Notably, the width of the inhibition zone surrounding the coated sutures remained consistently wide and stable for duration up to 7 days. This sustained and robust inhibitory effect against gram-positive bacteria, specifically S. aureus and S. mutans, serves as strong evidence of the antibacterial efficacy of the coated sutures. Conclusion: The coating of silk sutures with AgNPs provided a significant and effective antibacterial capacity to the surgical sutures, with this activity being sustained for a period of 7 days. This suggests that AgNPs-in situ photoreduction deposited sutures have the potential to effectively manage S. aureus and S. mutans infections.