Synthesis of magnetic mesoporous silica composites via a modified Stober approach

In this work, magnetic Fe3O4@mesoporous silica composites were synthesized by a microemulsion (oil-in-water/ethanol) approach which was applied with a modified Stober reaction. Cetyl trimethyl ammonium bromide was employed as the surfactant, nano-Fe3O4 particles were dispersed in microemulsion. Tetraethyl orthosilicate (TEOS) formed oil drops, and ammonia solution facilitated the hydrolysis polymerization of TEOS. The diameters of the magnetic Fe3O4@mesoporous silica composites can be tuned within the range 120-380 nm by varying the ratio of ethanol/water and the amount of nano-Fe3O4 particles. Brunauer-Emmett-Teller surface areas of magnetic Fe3O4@mesoporous silica composites were determined to be within the range 490-759 m(2)/g and their pore sizes were around 2.3 nm as it was determined by Barrett-Joyner-Halenda method. Furthermore, the encapsulation of poorly water-soluble drugs within magnetic Fe3O4@mesoporous silica composites was investigated using protoporphyrin IX. Magnetic Fe3O4@mesoporous silica composites showed a drug loading within 22-68 mg/g, which can be an excellent drug delivery platform for photodynamic therapy.