The elaboration, characterisation and efficiency of potential two-photon-excited photodynamic therapy (PDT) treatment of new poly(d,l-lactide-co-glycolide) nanoparticles loaded with ruthenium(II) complexs are presented. The materials are based on the encapsulation of RuII complexes through an all-biocompatible process. The size of the nanoparticles is around 100 nm. The internal concentration is several orders of magnitude higher than the overall concentration, which leads to a more efficient and targeted effect. The therapeutic potential for PDT of these nanoparticles has been studied in vitro on C6 glioma cells.