Nanoparticles in lysine-silica sols

The formation process of silica nanoparticles by the addition of tetraethylorthosilicate (TEOS) to an buffered, aqueous solution of lysine, is discussed. Optically clear mixtures can be prepared from lysine, TEOS, and water to give a specific molar composition. Clear sols were prepared by initially mixing lysine with distilled water, followed by addition of the prescribed amounts of TEOS. Small-sngle X-ray scattering (SAXS) patterns were collected to characterize the lysine-silica mixtures and to quantatively detect nanoparticles. It was observed that the formation of nanoparticles is limited by the rate of TEOS hydrolysis. This formation phenomena opens possibilities for application of the nanoparticles as high purity reagents for synthesis of biocompatible silicates, nanocomposites, films, and gels.