Analysis of the Effect of Fabrication Parameters on the Properties of Biopolymer Coatings Deposited on Ti13Zr13Nb Alloy

This work describes the preparation and characterization of chitosan-based biopolymer coatings containing silver, zinc, and hydroxyapatite nanoparticles deposited on the Ti13Zr13Nb alloy by the EPD method. It was intended to evaluate the influence of surface pretreatments and deposition parameters on the structural, electrochemical, and biological properties of coatings. The morphology and composition were characterized by means of SEM/EDS, AFM, XRD, and FTIR analysis. The obtained results indicated uniform continuous layers with homogeneously distributed nanoparticles and the presence of characteristic functional groups originating from chitosan and hydroxyapatite. Corrosion investigations performed in SBF solution revealed a significant enhancement in corrosion resistance for chitosan/nanoAg/nanoZn/nanoHAp coatings, reflected in a drastic decrease in corrosion current density compared with uncoated Ti13Zr13Nb alloy. The contact angle measurements confirmed their hydrophilic nature, which favors better biointegration ability. Biological tests (MTT and LDH) performed on human osteoblasts (hFOB 1.19) confirmed high biocompatibility (>85% cell viability) in the case of all coatings with the addition of hydroxyapatite, whereas in the case of coatings without HAp, cytotoxicity was observed, probably due to the uncontrolled release of metallic nanoparticles. These findings suggest that the presence of hydroxyapatite in chitosan-based coatings efficiently enhances corrosion protection and cytocompatibility, showing very good prospects for biomedical applications such as the surface modification of titanium implants.