Towards the controlled release of metal nanoparticles frombiomaterials: Physico-chemical, morphological and bioactivityfeatures of Cu-containing sol–gel glasses

Two Cu-containing bioactive glasses were prepared and characterized in order to obtain a detaileddescription of chemical, morphological and bioactivity proprieties of potential Cu releasing systems. Thecharacterization has demonstrated that by varying the synthesis procedure is possible to obtain two sys-tems with Cu species in two different oxidation states and aggregation: (i) SGCu(ox) – oxidated Cu – (Cuoxidation state +2) homogeneously dispersed in the glass network matrix and (ii) SGCu(red) – metallic Cu– (Cu oxidation state 0) containing nano-particles (5–130 nm range) mainly present on the glass surface.The introduction of Cu maintains the bioactivity of the Cu-containing glasses almost unchanged, inducinga partial delay in the hydroxyapatite/hydroxy-carbonate apatite (HA/HCA) formation on the glass surfacewith respect to the reference glass (free Cu glass). During the bioactivity test, Cu is released from bothCu-containing glasses, in particular in the case of the SGCu(red) the presence of Cu nanoparticles (CuNPs)of diameter in the range 5–10 nm has been detected in solution.