Nickel coating on plasmonic copper nanoparticles lowers cytotoxicity and enables colorimetric pH readout for antibacterial wound dressing application†

Wound infection poses a significant challenge to the natural healing process. It can impede various stages of wound healing, thereby hindering tissue regeneration and increasing the risk of systemic complications. Wound dressings emerged as a crucial option in the management of infections. Herein, we investigate fabrics coated with copper-based nanoparticles for potential wound dressing application. We synthesized copper and copper–nickel (Cu–Ni) core–shell nanoparticles via a polyol synthesis and investigated their particle growth dynamics and chemical stability. The nickel coating stabilized the nanoparticles against oxidation and dissolution, while dampening the localized surface plasmon resonance of copper. When coated on the fabrics, we found that Cu–Ni NPs were slightly less effective as an antibacterial agent than Cu NPs, however the cytotoxicity of Cu–Ni NPs was significantly reduced compared to pure Cu. Additionally, we show that the discoloration of nanoparticle-coated fabrics depended on pH, thus enabling the visualization of pH levels of simulated wound fluids which can provide information on the inflammatory state of the wound. Our work contributes to the understanding of copper-based nanoparticles and their potential applications in healthcare.