Electrophoretic deposition of organic/inorganic composite coatings containing ZnO nanoparticles exhibiting antibacterial properties

•Organic-inorganic composite coatings produced by electrophoretic deposition•Antibacterial ZnO nanoparticles incorporated in alginate coatings•Bioactive glass added to impart bioactivity in multifunctional coatings

To address one of the serious problems associated with permanent implants, namely bacterial infections, novel organic/inorganic coatings containing zinc oxide nanoparticles (nZnO) are proposed. Coatings were obtained by electrophoretic deposition (EPD) on stainless steel 316L. Different deposition conditions namely: deposition times in the range 60-300 s and applied voltage in the range 5-30 V as well as developing a layered coating approach were studied. Antibacterial tests against gram-positive Staphylococcus aureus and gram-negative Salmonella enteric bacteria confirmed the activity of nZnO to prevent bacterial growth. Coatings composition and morphology were analyzed by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Moreover, the corrosion resistance was analyzed by evaluation of the polarization curves in DMEM at 37 °C, and it was found that coatings containing nZnO increased the corrosion resistance compared to the bare substrate. Considering all results, the newly developed coatings represent a suitable alternative for the surface modification of metallic implants.