Aqueous electrophoretic deposition of yttrium-doped nanobioactive glass/collagen/chitosan orthopedic coatings on 316L SS

The current study used yttrium-doped nanobioactive glass (Y-nBG), based on 62 SiO₂ – (33 – x) CaO – 5 P₂O₅ – x Y₂O₃ mole % system (x = 0 and 3 mol %), collagen, and chitosan composites for coating 316L stainless steel (316L SS) using aqueous electrophoretic deposition (EPD) technique. The corresponding coated samples are encoded as SS/Col-Chit, SS/BG-Y0/Col-Chit, and SS/BG-Y3/Col-Chit, respectively. Physicochemical characterization implied TGA, FTIR, SEM-EDX, contact angle, adhesion strength and in vitro bioactivity in SBF were performed. Following SBF immersion, FTIR and SEM-EDX investigations were also carried out. Furthermore, the coatings were loaded with gentamicin drug; the drug-release profile and mechanism were evaluated. The antibacterial efficacy of the composite coatings was also assessed. The results showed the formation of homogeneous coatings with good adhesion strength, 1.39 MPa, 0.55 MPa, and 0.81 MPa, and enhanced the wettability by decreasing the contact angle 36⁰, 22⁰ and 12⁰ for SS/Col-Chit, SS/BG-Y0/Col-Chit and SS/BG-Y3/Col-Chit coatings, respectively. In vitro bioactivity of coatings containing nBG revealed apatite formation after immersion in SBF. Furthermore, the antibiotic gentamicin showed a sustained release profile over time by diffusion mechanisms based on the Higuchi, Fickian, and Weibull models. As well, all coatings containing drugs have an antibacterial effect. Overall, these findings suggested that the prepared coatings have potential applications as orthopedic and dental implants.