Fibrous-structured magnetic and mesoporous Fe3O4/silica microspheres: synthesis and intracellular doxorubicin delivery

A novel, fibrous-structured bifunctional (magnetic and mesoporous) Fe3O4/silica microsphere was successfully synthesized through a simple and economical self-assembled process in which hydrophobic 9 nm-Fe3O4 nanocrystals were directly used without modifications. The obtained material is performed as a drug delivery carrier to investigate the in vitro and intracellular delivery properties of doxorubicin hydrochloride (DOX). X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N-2 adsorption/desorption, Fourier transform infrared spectroscopy (FTIR), and superconducting quantum interference device (SQUID) were employed to characterize the composite. The results reveal that the novel composite exhibits typical mesoporous structure, narrow size distribution, good monodispersity, and superparamagnetic features. Notably, confocal laser scanning microscopy (CLSM) images indicate that the DOX-loaded sample could deliver DOX into the nuclei of HeLa cells to kill cells. Also, MTT assay confirms that the DOX-loaded sample leads to pronounced and efficient cytotoxic effects to L929 fibroblast cells, even similar to that of free DOX at high concentrations, whereas the pure material is non-toxic. Therefore, the novel material is expected to have potential application for targeted cancer therapy.