The present invention relates to a substrate of a metal, preferably titanium or a titanium alloy, having at least one surface coated with an oxide layer of the metal itself, said surface being modified and enriched with Ca, P, Ga, Sr, and, optionally, Ag by anodic spark deposition (ASD). The present invention also relates to a process for producing said substrate by applying the anodic spark deposition (ASD) technique to a substrate, optionally pre-treated, immersed in an electrolytic solution comprising Ca, P, Ga, Sr and, optionally, Ag. Finally, the present invention also relates to a prosthesis and a surgical implant comprising or preferably produced with said substrate, as well as the use thereof for the prevention of bacterial colonisation and promotion of osteointegration in implantology operations, preferably orthopaedic prosthetic implantology.