Combination of Noble Metal and Gold-Silver Nanoclusters as Enhanced Antibacterial Coatings for Ti-Based Medical Implants.

The surface modification of medical implant materials stands as a favorable strategy to enhance their biological properties including their antibacterial effect and biocompatibility. Recently, both in vitro and in vivo studies have shown that film heterostructures based on a combination of noble metal sublayers and an active component, such as silver and gold nanoparticles, offer unique advantages. The present work develops this promising direction and focuses on a series of combinations of noble metal coatings functionalized with bimetallic nanoclusters obtained by vapor-phase deposition methods onto the surfaces of Ti-based implants. This investigation investigates the influence of sequential deposition (AgAu or AuAg) and noble metal component (Ir or Au) on the coating morphology and the active component chemical form and release. Thus, scanning electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy have been applied to characterize the samples before and after in vivo biological studies (rat models, 1 and 3 months). Histological and blood analyses confirmed the high biocompatibility of all the heterostructures. The samples also showed a pronounced in vitro biocidal effect against Gram-positive (S. epidermalis) and Gram-negative (P. aeruginosa) bacteria that correlates with a dynamic of silver release. The AuAg/M heterostructures demonstrated superior biological characteristics compared to their AgAu/M counterparts, suggesting enhanced both long-term integration and antibacterial action.