Bioactive and Antibacterial Ti-6Al-4V Surfaces Prepared by Shifted Laser Texturing and Silver Thin Film Deposition

The development of multifunctional surfaces on titanium implants is a critical strategy for mitigating post-operative infections and enhancing long-term clinical integration. This study investigates a dual-stage surface modification of the Ti6Al4V alloy, combining shifted Laser Surface Texturing (sLST) with functional ethanol-based silver coatings. The novelty of this research lies in the synergistic combination of advanced sLST surface engineering, which creates a hexagonal "reservoir" topography, and the stable functionalization of these complex structures with antimicrobial silver particles. Initially, the substrates were laser-processed to create a defined hexagonal surface morphology, followed by the deposition of silver-containing) and silver-free coatings via dip-coating and subsequent heat treatment. Comprehensive surface characterization confirmed a homogeneous distribution of silver particles within the porous laser-textured structure, with silver concentrations in the resulting extracts reaching several mg/l. Biological evaluation revealed that the silver-doped coatings achieved nearly 100% antibacterial efficacy against Escherichia coli after 24 hours, showing zero or only negligible colony growth compared to the silver-free and reference samples. Cytotoxicity testing with extracts using L929 fibroblasts demonstrated that all modified surfaces maintained relative metabolic activity above 70% threshold, thus qualifying as non-toxic according to ISO 10993-5 standards. Despite this high metabolic viability, microscopic analysis revealed localized impairments in cell morphology, suggesting a complex cellular response that may be influenced by preparation-related factors. The integration of sLST texturing with Ag-doped ethanol coatings represents a highly effective approach for producing antimicrobial titanium surfaces with maintained cytocompatibility, offering significant potential for advanced orthopaedic and dental applications.