Abstract:

Hollow inorganic particles have attracted great interest because of their unique physicochemical properties. In this study, a simple and effective method for synthesizing silica hollow spheres is presented. The synthesis utilizes CaCO3 as spherical templates for the silica growth； tetraethyl orthosilicate(TEOS) is added to the template as a precursor for the silica formation. After CaCO3 spherical cores were removed by adding diluted hydrochloric acid, hollow silica spheres with smooth surface and uniform shell thickness around 60~70 nm were obtained. The core shell structure of CaCO3 sphere-silica composites and the hollow structure of silica spheres were characterized by FESEM, TEM, TGA, XRD and FTIR. The results indicated that the silica was coated on the surface of CaCO3 spheres. The inner diameter of the hollow silica spheres with amorphous shell was about 1~2 μm. Amine functional silica hollow spheres were prepared via the hydrolysis of APTMs, then alginate was firstly grafted onto the surface of amine silica then the alginate coating was immobilized by gelling Ca2+ ions and alginate, which allows the formation of alginate-modified hollow SiO2. The size of microsphere is about 1~2 μm. Daunorubicin as a probing drug was loaded into the carrier, the maximum percent of envelop and load were 55.6% and 27.8% respectively.

Key words: CaCO3, hollow SiO2, alginate, microsphere, daunorubicin