Electrophoretic Deposition and Characterization of Multicomponent Chitosan/Eudragit or Poly(4-vinylpyridine) Coatings Incorporating Mesoporous Bioactive Glass and Silver Nanoparticles on Ti-13Nb-13Zr Alloy

In this study, multifunctional composite coatings based on chitosan (CS), mesoporous bioactive glass nanoparticles (MBGNPs), and silver nanoparticles (AgNPs) were successfully deposited on Ti-13Nb-13Zr alloy by electrophoretic deposition (EPD). Two coating systems containing Eudragit E100 (EE100) or poly(4-vinylpyridine) (P4VP) were developed to tailor physicochemical and biological properties. The synthesized MBGNPs exhibited a spherical morphology with an average particle size of approximately 80 nm, as observed by TEM, while XRD analysis confirmed their amorphous structure. Both coatings formed uniform porous layers (∼10 µm thick) with excellent adhesion to the substrate (class 1, EN ISO 2409). Surface characterization revealed significantly increased roughness and distinct wettability behavior depending on polymer composition. CS/EE100 coatings exhibited hydrophobic character and low surface free energy, whereas CS/P4VP coatings showed highly hydrophilic behavior with increased surface energy. Electrochemical studies demonstrated enhanced electrochemical activity of coated samples, particularly for the P4VP-based system, associated with its porous and hydrophilic structure. Ion release studies confirmed time-dependent calcium release from MBGNPs and significantly higher silver ion release from CS/P4VP coatings, especially under acidic conditions. Both coatings exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus, achieving up to ∼2.4 log reduction. Cytocompatibility studies using hFOB 1.19 osteoblast-like cells demonstrated that the CS/P4VP/MBGNPs/AgNPs coating maintained high cell viability (>80%) despite increased Ag+ release, while both coatings maintained alkaline phosphatase activity. Overall, the P4VP-based coating demonstrated the most favorable balance between antibacterial activity, ion release, and cytocompatibility, highlighting its potential for advanced biomedical implant applications.