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

Abstract

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 <i>Staphylococcus aureus</i> (<i>S. aureus</i>)-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 <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>) and <i>Escherichia coli</i> (<i>E. coli</i>), while up to 60% for Gram-positive <i>S. aureus.</i> AuNst conjugated hydrogel (AuNst₁₂₀@H) reduced >80% colonies of <i>P. aeruginosa</i> and <i>E. coli</i>. In comparison, around 35.4% reduction of colonies are obtained for <i>S. aureus</i>. 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 AuNst₁₂₀@H. A significant reduction in wound size is observed on the 10th day in AuNst₁₂₀@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.