Mechanobactericidal, Gold Nanostar Hydrogel-Based Bandage for Bacteria-Infected Skin Wound Healing.

The emergence of multidrug resistant (MDR) microorganisms has led to the development of alternative approaches for providing relief from microbial attacks. The mechano-bactericidal action as a substitute for antimicrobials has become the focus of intensive research. In this work, nanostructure-conjugated hydrogel are explored as a flexible dressing against Staphylococcus aureus ( S. aureus )-infected skin wounds. Herein gold nanostars (AuNst) with spike lengths reaching 120 nm are probed for antibacterial action. The bacterial killing of >95% is observed for Pseudomonas aeruginosa ( P. aeruginosa ) and Escherichia coli ( E. coli ), while up to 60% for Gram-positive S. aureus. AuNst conjugated hydrogel (AuNst 120 @H) reduced >80% colonies of P. aeruginosa and E. coli . In comparison, around 35.4% reduction of colonies are obtained for S. aureus . The viability assay confirmed the presence of about 85% of living NIH-3T3 cells when grown with hydrogels. An animal wound model is also developed to assess the efficiency of AuNst 120 @H. A significant reduction in wound size is observed on the 10th day in AuNst 120 @H treated animals with fully formed epidermal layers, hair follicles, new blood vessels, and arrector muscles. These findings suggest that novel dressing materials can be developed with antimicrobial nanotextured surfaces.