P(EO-co-LLA) functionalized Fe3O4@mSiO2 nanocomposites for thermo/pH responsive drug controlled release and hyperthermia

Abstract

The Fe₃O₄@mSiO₂ nanocarrier that consisted of a magnetic Fe₃O₄ nanoparticle core and a mesoporous silica (mSiO₂) shell was synthesized. It shows a uniform sphere morphology about 65 nm in diameter. Considering the magnetic hyperthermia of Fe₃O₄ under an alternating magnetic field (AMF), a thermo-sensitive polymer, poly[(ethylene glycol)-co-(L-lactide)] (P(EO-co-LLA)), was used as “gatekeeper” coating outside Fe₃O₄@mSiO₂ to regulate the drug release behavior. The design of the nanocarrier was expected to block off the pores at low temperature and to reopen them at high temperature reversibly. The obtained hybrid nanocomposites were capable of loading the anti-cancer drug doxorubicin (DOX) and controlled drug release behavior trigged by the hyperthermia of Fe₃O₄ under AMF. Besides, the nanocarriers also show pH-sensitive drug release based on the slight differences between the tumor (weakly acid) and the normal tissue (weakly alkaline). What's more, the chemotherapy of DOX combined with magnetic hyperthermia can improve the cytotoxicity obviously. On the basis of the high stability and excellent controlled release performance, the multifunctional nanocarriers exhibit potential applications in targeted-control drug release and hyperthermia for cancer treatment.