Search

Tubular mesoporous silica (T-mSiO2) was facilely synthesized through a co-template method by using cetyltrimethylammonium bromide and α-Fe2O3 as the dual templates, and then disulfide (–SS–) bonds and carboxyl groups (–COOH) were introduced to the resultant T-mSiO2 via the reaction with 2-carboxyethyl 2-pyridyl disulphide. The obtained –SS– grafted T-mSiO2 (SS-T-mSiO2) was then grafted with chitosan (CS) via the amidation reaction between the –COOH groups on SS-T-mSiO2 and the –NH2 groups on CS. The CS grafted SS-T-mSiO2 (CS-SS-T-mSiO2) was fully characterized by various technologies such as transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Finally, the as-synthesized CS-SS-T-mSiO2 was used as the carrier for redox and pH dual-triggered delivery of 5-fluorouracil (5-FU), an anti-cancer drug, and the results indicate that the developed CS-SS-T-mSiO2 might be a potential responsive carrier for redox and pH dual-triggered drug delivery.

Near-infrared (NIR) light has great potential in biomedical applications due to its advantages of deep penetration depth and low photodamage to biological tissues. In this paper, we constructed a novel core-shell structured drug nanocarrier, Fe3O4@Au@SiO2, for the controlled delivery of etoposide (VP16), a chemotherapeutic drug for cancer patients. The novel core-shell structured drug delivery platform is composed of a mesoporous silica shell and a magnetic Fe3O4 core using Au nanoparticles (AuNPs) as the interlayer, which is characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N2 adsorption/desorption isotherms and the magnetic measurements with vibrating-sample magnetometer (VSM). The synergistic effects of AuNPs, mesoporous silica and Fe3O4 make the core-shell structured nanocomposites an excellent candidate for targeted and NIR light irradiation-controlled drug delivery. For the proposed nanocarrier of VP16, the mesopores in silica can enhance the encapsulation capacity of the nanocarrier and the AuNPs can effectively convert the NIR light into heat to speed up the drug deliver; meanwhile, the incorporation of Fe3O4 with high magnetization to the drug delivery platform realize drug targeting under an applied external magnetic field.