Synthesis of porous magnetic hollow silica nanospheres for nanomedicine application

A porous magnetic hollow silica nanosphere (MHSN) is a new nanostructured drug carrier for increasing drug loading capability. Keeping the magnetic nanoparticles in the hollow core will limit the toxicity and degradation in a biosystem. In this paper, we report a synthesis of porous MHSNs by sol-gel method. CaCO3/ Fe3O4 composite particles were first fabricated by embedding Fe3O4 nanoparticles into CaCO3 using the rotating packed bed (RPB) method. Tetraethoxysilane (TEOS) was then added as precursor to form a silica (SiO2) layer on the surface of CaCO3/Fe3O4 composite particles. Hexadecyltrimethylammonium bromide (CTAB) and octane act as second templates for the formation of porous silica shells. After removing the surfactants by calcination and etching away the CaCO3 particles, porous MHSNs with magnetite (Fe3O4) nanoparticles inside the cores were formed. The pore size can be tuned by adjusting the amount of the cationic surfactant absorbed on the surface of the composite particles to form self-assembled nanochannels. lbuprofen was loaded on or into the porous MHSNs, and the drug encapsulation and release were investigated. A slow release was observed for the porous MHSNs, which demonstrated MHSNs are potential carriers for controlled releasing in nanomedicine application.