RADIOLABELED SE-75-SILICA NANOPARTICLES - SYNTHESIS, CHARACTERIZATIONAND COATING WITH OMEGA-FUNCTIONALIZED ALKYLSILANE COMPOUNDS

The synthesis and characterization of new radiolabeled Se-75-silica na noparticles are described. These particles have been prepared by dispe rsion polymerization of tetraethylorthosilicate in ethanol in presence of radiolabeled (75)selenium-colloids. The amount of Se-colloids enca psulated within the silica matrix was then increased by two successive seeded polymerizations of tetraethylorthosilicate on the previously f ormed particles. Kinetic studies and the effect of various factors, i. e. sodium selenite, water and ammonium hydroxide concentrations, on th e diameter of these nanoparticles have been elucidated. The Se-silica nanoparticles have been covalently coated by the self-assembled techni que with a variety of omega-functionalized alkylsilane compounds. Char acterization of these coatings has been performed by Fourier transform -infrared spectroscopy, elemental analysis and floatability studies. T he potential use of these varieties of omega-functionalized radiolabel ed nanoparticles for drug delivery purposes has been demonstrated in a separate article.