Surface Functionalisation of Hyaluronic Acid-Based Foams with TiO2 via ALD: Structural, Wettability and Antimicrobial Properties Analysis for Biomedical Applications

The aim of this study was to evaluate the effect of surface modification of porous hyaluronic acid (HA)-based materials with a titanium dioxide (TiO₂) layer deposited via atomic layer deposition (ALD) on the selected structural, physicochemical, and antimicrobial properties of materials intended for applications in regenerative medicine. The obtained HA-based materials, enriched with silk and elastin, were analyzed in terms of their rheological behavior, wettability, solubility, and resistance to colonization by clinically relevant bacterial pathogens (<i>Staphylococcus aureus</i>, <i>Klebsiella pneumoniae</i>) and environmental filamentous fungi (<i>Aspergillus niger</i>, <i>Chaetomium globosum</i>). The results demonstrated that even a thin, continuous TiO₂ layer formed after 200 ALD cycles reduced the hydrophilicity of the foams, indicating improved durability in aqueous environments. Microbiological tests confirmed enhanced antimicrobial properties of the foams after TiO₂ modification-showing inhibition of both tested bacterial strains and <i>C. globosum</i> within 24 h. These findings suggest that surface functionalization of hyaluronic acid-based foams with a TiO₂ layer can improve both their environmental stability and, to some extent, reduce microbiological risk, while preserving the layered-porous structure of the foams, which is advantageous for biomedical applications.