Biocompatible Nano Composite Coating on 316L Stainless Steel Surface for Bone Implant Application

This work deals mainly with the influence of nano titanium dioxide with addition of nano hydroxyapatite to get more adhesive coatings on 316L stainless steel by the electrophoretic deposition method. An adherent thin nano composite coating was obtained on a metal surface at 30 V and 2 minutes sintering at 700°C. The surface morphology and surface topography were characterized by X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, and surface profilometry, respectively. The adhesion strength of the composite coatings was evaluated using a tape test method, and mechanical strength was measured by the Vickers microhardness test. Further, the corrosion behavior of the coated and uncoated samples was tested in Hank's solution using electrochemical impedance spectroscopy and cyclic potentiodynamic polarisation studies. In vitro analyses were carried out with MC3T3-E1 osteoblast cells. The nano composite coated sample exhibited higher adhesion, enhanced corrosion resistance with improved cell attachment and more cells proliferation compared to those of the uncoated sample, the protective layer of the former controlling the release of metal ions into the biological system.