The present invention relates to nanomaterials comprised of metal oxides associated with cationic metals having antibacterial activity. In particular, the present invention relates to nanocrystalline compounds of formula (I) : AOx- (L-Men+) i, (I) where AOx represents the metal oxide or metalloid oxide, with x = 1 or 2; Me11'1' is a metal ion having antibacterial activity, with n = 1 or 2; L is a bifunctional molecule, either organic or organometallic, capable of binding simultaneously with the metal oxide or metalloid oxide and the metal ion Men+; and i represents the number of L-Men+ groups bound to a AOx nanoparticle