Synthesis of magnetic mesoporous silica composites via a modified Stöber 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 Stöber 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 m2/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.