Folate-Conjugated Fe₃O₄@SiO₂ Hollow Mesoporous Spheres for Targeted Anticancer Drug Delivery

Abstract

Herein we developed a targeted anticancer drug delivery system based on folate-conjugated rattle-type Fe₃O₄@SiO₂ hollow mesoporous spheres combining receptor-mediated targeting and magnetic targeting. Folic acid (FA) ligands were successfully grafted onto rattle-type Fe₃O₄@SiO₂ hollow mesoporous spheres via amide reaction. The magnetization saturation value of folate-conjugated Fe₃O₄@SiO₂ spheres (Fe₃O₄@SiO₂−FA) was about 1.6 emu/g, and these spheres could be targeted under an external magnetic field. On the other hand, in vitro cytotoxicity and cell uptake of these Fe₃O₄@SiO₂−FA spheres to Hela cells were evaluated. These Fe₃O₄@SiO₂−FA spheres were nontoxic up to a concentration of 150 μg/mL, and further can be specifically taken up by Hela cells via FA receptor-mediated endocytosis. Doxorubicin hydrochloride (DOX), an anticancer drug, was introduced into Fe₃O₄@SiO₂−FA spheres. The release of DOX from Fe₃O₄@SiO₂−FA spheres had a sustained release pattern, and the DOX-loaded Fe₃O₄@SiO₂−FA spheres exhibited greater cytotoxicity than free DOX and DOX-loaded Fe₃O₄@SiO₂ spheres due to the increase of cell uptake of anticancer drug delivery vehicles mediated by the FA receptor. Therefore, we conclude that folate-conjugated Fe₃O₄@SiO₂ hollow mesoporous spheres have potential for targeted anticancer drug delivery for cancer therapy.