Synthesis of Monodisperse Silica Particles by Controlled Regrowth

The development of a simple and reproducible method for the synthesis of monodisperse silica particles is of considerable interest from the point of view of their numerous applications in photonics, biosensing, and biomedicine. When using the well-known Stober method, there is a continuous formation and growth of seeds, which leads to the synthesis of polydisperse colloids. In this work, we used the method of successive growth of silica particles obtained by hydrolytic condensation of tetraethylorthosilicate in an alcoholic-aqueous medium using an alkaline catalyst. It is shown that this technique makes it possible to obtain colloids with a particle size from 50 nm to 3 mu m and a standard deviation of less than 5%. An additional advantage of the developed method of stepwise growth is the possibility to include fluorophores and SERS tags into the silica matrix.