Magnetic mesoporous silica nanoparticles end-capped with hydroxyapatite for pH-responsive drug release

Abstract

Mesoporous silica nanoparticles (MSNs) have emerged as one of the most promising vehicles for potential application in drug delivery. In this paper, we report a novel multifunctional nanocomposite composed of a magnetite nanocrystal core and a mesoporous silica shell (Fe₃O₄@mSiO₂), end-capped with pH-stimuliresponsive hydroxyapatite (HAp) nanovalves for pH-responsive drug release. Iron oxide core and mesoporous silica shell nanoparticles were synthesized using a microemulsion method, and were then employed as templates for surface coating of hydroxyapatite. The efficient coating of the natural nontoxic component hydroxyapatite was achieved through a biomimetic mineralization process. The pH-responsive release of the model drug ibuprofen showed that the Fe₃O₄@mSiO₂@HAp nanoparticles possessed pH-responsive drug-release functionalities. The dissolution of hydroxyapatite in an acidic environment triggers the release of the loaded drugs in Fe₃O₄@mSiO₂@HAp nanoparticles.