Synthesis by anodic-spark deposition of Ca- and P-containing films on pure titanium and their biological response

•​CP-4 Ti was treated by anodic spark oxidation in the electrolyte containing Ca and P ions by varying process time and electrolyte concentration.•Ca/P ratio in layers is 0.23–0.47, much lower than in hydroxyapatites (1.67). It means coatings should be resorbable in a biological medium•After immersion in SBF, Ca and P content in layers decrease. Ca and P loss occurs faster in thin layers than in thicker coatings.•The biological response of the samples suggests their excellent biocompatibility and even stimulating effects on osteoblasts proliferation. The purpose of this work is to characterize the anodized layers formed on titanium by anodic-spark deposition in an electrolyte containing Ca and P ions, Ca3(PO4)2, studied for the first time. The oxidation experiments were performed at different periods of time and using different concentrations of electrolyte. The influence of the process parameters (time of electrolysis and electrolyte concentration) on the surface morphology and chemical composition of the anodized layers was studied. It has been found that it is possible to incorporate Ca and P into the growing layer. A response of the anodized layers in a biological medium was evaluated by their immersion in a simulated body fluid. An enrichment of titanium and a simultaneous loss of calcium and phosphorus in the layer after immersion tests indicate that these coatings should be bioresorbable in a biological medium. Preliminary biological assays were performed on some anodized layers in order to assess their biocompatibility with osteoblast cells. The cell proliferation on one selected anodized sample was assessed up to 21days after seeding. The preliminary results suggest excellent biocompatibility properties of anodized coatings.