title: Bioactive glasses containing Au nanoparticles. Effect of calcination temperature on structure, morphology, and surface properties.
abstract: Bioactive glasses containing gold nanoparticles (AuNPs) have been synthesized via the sol-gel route using HAuCl(4) x 3 H(2)O as gold precursor. The formation process of AuNPs was studied as a function of the thermal treatment, which induces nucleation of Au particles and influences their nature, optical properties, shape, size, and distribution. The physicochemical characterization indicates that the sample treated at 600 degrees C presents the best characteristics to be used as a bioactive material, namely high surface area, high amount of AuNPs located at the glass surface, presence of micropores, and abundant surface OH groups. In the case of samples either aged at 60 degrees C or calcined at 150 degrees C, AuNPs just begin their formation, and at this stage the gel is not completely polymerized and dried yet. A thermal treatment at higher temperatures (900 degrees C) causes the aggregation of AuNPs, forming "AuMPs" (i.e., Au microparticles) in a densified glass-ceramic material with low surface area, absence of pores, and low number of surface OH groups. These features induce in the glass-ceramic materials treated at high-temperatures a lower bioactivity (evidenced by SBF reaction), as compared with that exhibited by the glass samples treated at 600 degrees C.
authors.affiliation: Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, 4110 Modena, Italy.
authors.forename: Gigliola
authors.initials: G
authors.lastname: Lusvardi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Malavasi
authors.forename: Valentina
authors.initials: V
authors.lastname: Aina
authors.forename: Luca
authors.initials: L
authors.lastname: Bertinetti
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Cerrato
authors.forename: Giuliana
authors.initials: G
authors.lastname: Magnacca
authors.forename: Claudio
authors.initials: C
authors.lastname: Morterra
authors.forename: Ledi
authors.initials: L
authors.lastname: Menabue
mesh_terms: D005898:Glass / Q000737:chemistry*; D006046:Gold; D053768:Metal Nanoparticles / Q000737:chemistry*; D015394:Molecular Structure; D013499:Surface Properties; D013696:Temperature
chemical_list: D006046:Gold