Preparation and characterization of calcium phosphate deposited on gold nanoparticles

Metal nanoparticles and calcium phosphate bone fillers have attracted a great deal of attention for use in dental and biomedical applications for several years. The goals of this study were to explore the possibility of combining gold nanoparticles (AuNP) with calcium phosphate (CaP) and to characterize the properties of the resulting particles. Two types of stable AuNP were prepared and functionalized with mercapto-propyl-trimethyloxy-silane (MPTS), which led to efficient formation of a silicate shell with AuNP encapsulated within it. This silicate shell resulted in more efficient CaP deposition than on AuNP without the silicate modification. Diluted ion (10−4 M) concentrations were able to form uniform and non-crystalline silicate–CaP deposits. Conversely, solutions at higher ion concentrations (10−3 M) formed a crystalline precipitate of needle-like apatite, but they were not uniformly dispersed and the solution did not evenly deposit the AuNP. The silicate–CaP deposited on the modified AuNP surface could serve as a medium or could be combined with bone cement for biomedical applications.