Magnetic core-mesoporous shell nanocarriers with drug anchorages suspended in mesopore interior for cisplatin delivery

The synthesis of the core-shell magnetic mesoporous silica nanocomposites has recently attracted much attention, while it is highly desirable to modify the mesoporous shell with organic components for special interaction with guest molecules. Herein we propose a facile strategy to prepare novel magnetic mesoporous nanocomposites with superparamagnetic Fe₃O₄ core and mesoporous silica shell functionalized with pendant carboxylic groups in their mesopore interior. The successful deposition of organic-inorganic mesoporous layer on magnetic nanoparticles is verified by XRD, TEM and BET characterizations, and the integration of organic units is manifested by FT-IR and solid state NMR techniques. The inherent carboxylic units on the obtained nanocomposites serve as effective drug anchorages for coordinating with Pt atoms in the anti-cancer drug of cisplatin, resulting in increased drug loading amount and its sustained release. The obtained nanocomposites exhibit excellent water dispersity with well-defined size distribution (around 85 nm), ordered mesoporous characteristics, superparamagnetism and high magnetization (37.0 emu g^-1). The nanocomposites could not only effectively transport the encapsulated cisplatin into cancer cells but also mediate its sustained release in endosomes or lysosomes, leading to enhanced antitumor efficiency against both A549 and MCF-7 cell lines.