Smart on-off responsive drug delivery nanosystems for potential imaging diagnosis and targeted tumor therapy

Cancer is one of the most concerned diseases in the world, where there is still no reported specifically targeted drugs with high effect. In this study, mesoporous silica with a large pore size of 25.25 nm and magnetic cores was prepared as a carrier of doxorubicin for anti-cancer drug delivery. Besides its superior biocompatibility properties and functional surface, the large mesopores provided enough space for multiple chemical modification and in-situ growth of Au nanoparticles. Amino groups were grafted on the inner mesopores to capture the drug molecules via complexation. Cooperated with the steric hindrance of beta-Cyclodextrin (beta-CD) on the external surface, a perfect response to acid environment was established. Meanwhile, the presence of magnetic cores and Au nanoparticles gave the system sensitive response to both alternating magnetic field (AMF) and near infrared ray (NIR). What's more, the combination of magnetic cores and Au nanoparticles provided a strong medical nuclear magnetic resonance (NMR) signal with a linear correlation of 0.9946. The accurate dose related NMR signal and the multi-stimuli sensitive response, including pH, AMF and NIR, make this system immense potential for imaging diagnosis and targeted drug delivery therapy.