SiO2-coated magnetic nano-Fe3O4 photosensitizer for synergistic tumour-targeted chemo-photothermal therapy.

Synthesis of SiO 2 coated magnetic Fe 3 O 4 nanoparticles as a DOX carrier and photosensitizer to enhance the synergistic effect of chemo-photothermal therapy for tumor treatment. • Size controllable magnetic Fe 3 O 4 @SiO 2 core-shell nanocomposites were synthesized by a modified Stǒber method. • Magnetic Fe 3 O 4 @SiO 2 have pH-responsive behavior in drug loading and release. • Fe 3 O 4 @SiO 2 can raise temperature to 55 °C for only 10 min irradiation by 808 nm light. • 81.3% of A549 cells are killed after incubated with Fe 3 O 4 @SiO 2 @DOX containing only 0.5 μg/mL of DOX and 15 min NIR irradiation • Tumor synergistic treatment is achieved by combination of chemotherapy and photothermal therapy. In this study, we integrated chemotherapy and photothermal therapy in a magnetically targeted doxorubicin-loaded Fe 3 O 4 @SiO 2 nanodrug system. Size-controllable magnetic Fe 3 O 4 @SiO 2 core-shell nanoparticles were synthesized via a solvothermal method and a modified Stǒber method. A molecular anticancer drug, namely, doxorubicin, was loaded onto Fe 3 O 4 @SiO 2 nanocomposites to form a magnetically targeted drug delivery system. This drug delivery system exhibits pH-sensitive effects on drug loading and release. The drug loading rate in a neutral environment is higher than that in an acidic environment; the opposite property is observed for the release rate. In addition, the magnetic Fe 3 O 4 @SiO 2 nanocomposites exhibit a satisfactory photothermal effect under NIR (808 nm) irradiation. The temperature can increase to 55 °C after only 10 min of irradiation, which effectively induces apoptosis of cancer cells in vitro. The cytotoxicity and cellular uptake of Fe 3 O 4 @SiO 2 @DOX nanodrugs were evaluated in A549 lung cancer cells. After treatment with Fe 3 O 4 @SiO 2 @DOX that contains only 10 μg/mL of DOX, 82.8% of A549 lung cancer cells can be killed. Furthermore, 81.3% of A549 lung cancer cells are killed after incubation with Fe 3 O 4 @SiO 2 @DOX that contains only 0.5 μg/mL of DOX and 15 min of NIR irradiation, thereby suggesting an excellent synergistic chemo-photothermal effect in tumour therapy. Our results suggest a new approach for the synthesis of a multifunctional, highly targeted, size-controlled nanodrug for tumour synergistic therapy. [ABSTRACT FROM AUTHOR]