Photothermal therapy (PTT) is a non-invasive therapy that is widely used in cancer treatment. Gold nanorods (AuNRs) are particularly suitable as a photothermal reagent due to their unique localized surface plasmon resonance (LSPR) properties. However, bare gold nanorods are not stable enough during radiation to collect enough energy to kill tumor cells. In addition, they showed some biologically toxic originated from the poor colloidal stability and surfactants cetyltrimethyl ammonium bromide (CTAB), making it difficult to apply them directly to clinical research. To solve these problems, a novel nanocomposite was structured by coating silica shell and gold nanocluster on the outer layer of the gold nanorod (AuNRs@SiO2@AuNCs). Compared with the bare gold nanorod, the nanocomposite with the core-shell structure showed superior photothermal effect. The photothermal conversion temperature reached 63 °C under a lower irradiation power. The photothermal conversion efficiency was enhanced to 77.6%. Its photothermal performance remained constant after five cycles of near-infrared laser irradiation, indicating excellent photothermal stability. In vitro cell imaging experiments show that AuNRs@SiO2@ AuNCs can effectively enter tumor cells. By 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis, cancer cells can be effectively killed when exposed to a near-infrared laser. During the synthesis process, the silica and gold nanoclusters replaced the toxic CTAB molecular layer on the surface of AuNRs. Therefore, AuNRs@SiO2@AuNCs has good biocompatibility and fluorescence characteristics. These results suggest that such AuNRs@SiO2@AuNCs nanocomposite shows great potential in imaging guided photothermal therapy for cancer.
Keywords: Cell imaging; Enhanced photothermal therapy; Multifunctional nanomaterial; Silica coated gold nanorods.
Copyright © 2020 Elsevier B.V. All rights reserved.