Assessing the bio-functional properties of TiO 2/Antibiotic electrophoretic deposits on segmented polyurethane-coated metallic surfaces

The development of coatings on medical-grade metallic supports, such as Titanium and 316L Stainless Steel, is crucial for enhancing biocompatibility, reducing degradation, and preventing infections in medical implants. In this sense, nanoparticles, ceramics, antibiotics, and synthetic and natural polymers have been included in the modification of implants. In this work, we present the development of hybrid coatings on medical-grade metallic substrates (Titanium II and 316L Stainless Steel) modified with a thin layer of a segmented polyurethane (Tecoflex 80A^(c)). For this, Anatase TiO₂ nanoparticles (nanotubes and spheres) as well as antibiotics (gentamicin sulphate and Nisin) are deposited via electrophoretic deposition (EPD) with water used as the solvent. Characterization of the obtained surfaces was carried out by SEM, contact angle, Raman spectroscopy, infrared spectroscopy, EDX, AFM, and thermogravimetric measurements. The bio-functional properties of our samples were tested with fibroblasts and bacteria. The results demonstrate the formation of porous surfaces with embedded particles and antibiotics, both within the pores and on the surface itself. The viability assay reveals improved performance for EPD samples containing nisin and nanoparticles. Physicochemical characterization confirms the successful incorporation of antibiotics with nanoparticles. The antibacterial properties show similar inhibition for Gram-positive and Gram-negative bacteria when gentamicin and nanoparticles are deposited compared to gentamicin alone.