Novel materials and methods, for preparation of coatings based on titanium dioxide for osteointegrated biomedical prostheses. The coatings are realized with nanomaterials having antibacterial properties, and have the purpose of promoting osteointegration of the implants, and, at the same time, reducing rejection attributable to inflammatory processes which derive from infections which may develop in the neighborhood of the implants. In particular, the present invention relates to an endo-osseous implant comprised of biocompatible metallic materials; characterized in that said implant comprises a coating comprised of nanocrystalline material comprising nanoparticles of formula (I) AOx- (L- Men+) i , (I) where AOx represents TiO2 or ZrO2; Men+ is a metallic ion having antibacterial activity, with n = 1 or 2; L is a bi functional organic molecule which can simultaneously bind to the metal oxide and to the metallic ion Men+; and i is the number of L-Men+ groups bound to one nanoparticle of AOx.