Synthesis and characterization of mesoporous magnetic nanocomposites wrapped with chitosan gatekeepers for pH-sensitive controlled release of doxorubicin.

Multifunctional nanocarriers based on the Fe3O4 nanoparticles core and mesoporous silica shell (mSiO2) were synthesized for controlled drug release through magnetic targeting and pH-sensitive performances. The developed Fe3O4@mSiO2 nanocarriers exhibited a suitable size (63nm) and good magnetic responsibility, doxorubicin (DOX) could be successfully loaded into the mesoporous of Fe3O4@mSiO2 via electrostatic interaction, and the drug loading content and loading efficiency are 29.3% and 93.6%, respectively. The chitosan (CS) was employed to wrap the Fe3O4@mSiO2-DOX as the blocking agent to inhibit premature drug release, and the final CS/Fe3O4@mSiO2-DOX exhibited excellent pH-sensitivity, 86.1% DOX was released within 48h at pH4.0. Furthermore, all the release behaviors fit the Higuchi model very well and a purely diffusion-controlled process played a major role on DOX release from CS/Fe3O4@mSiO2-DOX. In addition, MTT assays in human liver hepatocellular carcinoma cells (HepG2) demonstrated that the CS/Fe3O4@mSiO2-DOX had high anti-tumor activity, while the Fe3O4@mSiO2 nanocarriers were practically non-toxic. Thus, our results revealed that the CS/Fe3O4@mSiO2-DOX could play an important role in the development of intracellular delivery nanodevices for cancer therapy.