Gold nanorods coated with mesoporous silica shell as drug delivery system for remote near infrared light-activated release and potential phototherapy.

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod-like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase-changing molecules (1-tetradecanol, TD, T(m) 39 °C) as gatekeepers, as well as its ability to regulate the release of doxorubicin (DOX). Indeed, a nearly zero premature release is evidenced at physiological temperature (37 °C), whereas the DOX release is efficiently achieved at higher temperature not only upon external heating, but also via internal heating generated by the GNR core under near infrared irradiation. When tagged with folate moieties, GNR@MSNPs target specifically to KB cells, which are known to overexpress the folate receptors. Such a precise control over drug release, combining with the photothermal effect of GNR cores, provides promising opportunity for localized synergistic photothermal ablation and chemotherapy. Moreover, the performance in killing the targeted cancer cells is more efficient compared with the single phototherapeutic modality of GNR@MSNPs. This versatile combination of local heating, phototherapeutics, chemotherapeutics and gating components opens up the possibilities for designing multifunctional drug delivery systems.