Copper Nanoparticle Decorated Multilayer Nanocoatings for Controlled Nitric Oxide Release and Antimicrobial Performance with Biosafety

Biomedical device-related bacterial infections are a leading cause of mortality, and traditional antibiotics contribute to resistance. Various surface modification strategies have been explored, but effective clinical solutions remain limited. This study introduces a novel antibacterial nanocoating with copper nanoparticles (CuNPs) that triggers localized nitric oxide (NO) release. The multilayered nanocoating is created using branched polyethylenimine (BPEI) and poly(acrylic acid) (PAA) via a Layer-by-Layer assembly method. CuNP-decorated nanocoatings are formed by reducing copper ions coordinated with amine/carboxylic acid groups. In a physiological environment, CuNPs oxidize to Cu(I), promoting NO release from endogenous NO donors. The nanocoating's thickness is adjustable to regulate amount of CuNPs and NO flux. The optimal thickness for effective NO release against <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> is identified, preventing microbial adhesion and biofilm formation. Importantly, the coating remains cytocompatible due to minimal CuNPs, physiological NO levels, and stable coating properties under physiological conditions.