Engineering surgical stitches to prevent bacterial infection

Surgical site infections (SSIs) account for a massive economic, temporal, physiological, and psychological burden on patients and health care providers. It has been shown that sutures provide a surface to which bacteria can adhere, proliferate, and promote SSIs. Current methods for fighting postoperative SSIs involve the use of sutures coated with common antibiotics such as chlorohexidine or triclosan. Unfortunately, these antibiotics have been rendered ineffective in many cases due to the increasing rate of antibiotic resistance. A promising new avenue involves the use of metallic nanoparticles (NPs). Metallic NPs have been shown to exhibit low cytotoxicity and a strong propensity for killing bacteria while evading the typical antibiotic resistance mechanisms. In this work, we developed a novel metallic NPs dip-coating method for PDS-II sutures and explored the capabilities of a wide variety of metallic NPs coatings in killing bacteria while retaining the cytocompatibility of the suture. Our findings indicated that our non-toxic technique provided a homogeneous and well coating methodology for PDS-II sutures with a wide variety of metallic NP while maintaining the strength, structural integrity, and degradability of the suture. Excitingly, the metallic NP coatings possess strong in vitro antibacterial properties against P aeruginosa and S. aureus – varying the percentage of dead bacteria from ~ 40% (for MgO NPs) to ~ 95% (for Fe 2 O 3 ) compared to ~ 15% for uncoated PDS-II suture, after 7 days. All sutures demonstrated minimal cytotoxicity (cell viability > 70%) reinforcing the movement towards the use metallic NPs as a viable antibacterial technology. PDS II sutures were successfully coated by an easy and non-toxic dip-coating method using a variety of metallic nanoparticles, proving to be a promising new avenue of research to fight surgical site infections.