pH-Sensitive Gold Nanorods with a Mesoporous Silica Shell for Drug Release and Photothermal Therapy

A pH-sensitive nanocarrier has been developed for the controlled intracellular release of drugs. The nanocarrier, which is approximately 75 nm in size, is composed of a gold nanorod (GNR) core and mesoporous silica shell (GNR@mSiO(2)) and shows good stability and biocompatibility, and excellent photothermal effects. Doxorubicin hydrochloride (DOX), a typical anticancer drug, was adopted as the model drug, and was connected to the mesoporous silica through Schiff base bonding. The drug-loading nanocarriers (GNR@mSiO(2)-DOX) exhibit enhanced drug release under acidic conditions owing to the sensitive Schiff base linker, whereas at high pH values low levels of premature release can be detected. The sensitive release mechanism was further investigated by monitoring the zeta potential before and after drug release. HeLa cells were used as typical cancer cells, and detailed cell experiments were carried out to confirm the good biocompatibility, rapid uptake, and acid-enhanced drug delivery of GNR@mSiO(2)-DOX. Moreover, the synergistic effect of chemotherapy and hyperthermia (photothermal effect from GNRs) of the nanocarrier can be expected to lead to improved therapy effects on cancer treatment.