A new synthesis method for bright monodispersed core-shell colored silica submicron particles

In this paper, we aimed to develop a two-step approach for highly efficient synthesis of bright core-shell colored silica submicron particles (core-shell colored SiO2 SMPs) by coupling organic reactive dyes onto silica submicron particle (SiO2 SMPs). C.I. Reactive Blue 21 was selected as model dye to synthesize a core-shell blue silica submicron particle (core-shell blue SiO2 SMPs). 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (3APTMS) and C.I. Reactive Blue 21 were grafted simultaneously on the surface of particles in the aqueous solution to produce bright blue SiO2 SMPs. The effect of the amount of 3APTMS and C.I. Reactive Blue 21 on preparation of blue SiO2 SMPs was studied. To prevent dye on blue SiO2 SMPs from leaking, core-shell blue SiO2 SMPs were prepared in a pre-hydrolyzed Stober system. Scanning Electronic Microscopy (SEM) and Dynamic Light Scattering (DLS) were used to character the SiO2 SMPs, blue SiO2 SMPs, and core-shell blue SiO2 SMPs. The results indicate that the blue SiO2 SMPs and core-shell blue SiO2 SMPs synthesized under the optimal conditions with regular morphology and good dispersibility. Coupling efficiency of the C.I. Reactive Blue 21 was as high as 89.2% (the quality of dye coupled was about 70 mg/g SiO2). In the same way, six other different colored SiO2 SMPs were also prepared by introducing different color organic reactive dyes on SiO2 SMPs. The bright monodispersed core-shell colored SiO2 SMPs is promising to be used as sensitive and reproducible maker in immunoassay. A one-step approach for the high efficiently coupling of reactive dyes onto SiO2 SMPs in an aqueous solution to synthesize monodispersed colored SiO2 SMPs was designed. The hydrolysis and condensation of 3APTMS and dye coupling were preceded at the same time. After modification and coloration, a silica protection layer was grown onto the colored SiO2 SMPs to prevent the dye leakage and to make the colored SiO2 SMPs be pure silica surface. [GRAPHICS]