An Efficient Near-Infrared Photothermal Therapy Agent by Using Ag @ Oxides Nanoprisms in for Cancer Therapy

Abstract

Purpose: Photothermal therapy (PTT) have been used in cancer therapy in recent years. We created a new PTT agent --Silver-oxides core-shell nanoprisms (Ag@oxides NPs) that possess stronger near-infrared (NIR) absorption and higher phototherma conversion efficiency. The purpose of this study was to demonstrate Ag @oxides nanoprisms can be used as an effective PTT agent in vivo and vitro.

Methods: Ag NPs were synthesized using a seed-mediated procedure. Ag@oxides NPs were prepared via a simple sol-gel route. The thickness of the oxides shell can be precisely tuned from 1 to 15 nm through changing the reaction time and amount of oxides sol-gel precursor. Cytotoxicity of Ag NP was tested in B16F10 cells using MTT assay, and C57BL/6J mice with subcutaneous melanoma tumor model. For measuring the photothermal conversion performance of the Ag@oxides core-shell NPs, 1mL aqueous dispersion of Ag@oxides NPs with different concentrations were introduced in a quartz cuvette and irradiated with an 808 nm NIR laser at a power density of 2 W*cm-2. Ag@oxides NPs were added into the co-cultured medium with cancer cells or injected into the tumor body. The cells/tumor were exposed to an 808 nm laser at 2 W*cm-2 for 1 min, immediately. The photothermal effectiveness of Ag NP was evaluated by observing cellular survival using MTT assay and measuring the size of the tumor.

Results: We developed a facile method to synthesize Ag@oxides core-shell NPs with a tunable shell thickness through the simple sol-gel route. Ag@oxides exhibits a good biocompatiblity and stability for in vivo and vitro due to the existence of oxide shell layer. The localized surface plasmon resonance (LSPR) absorption band of Ag@oxides appeared at approximately 808 nm known as the Near-Infrared Window. When the light at 808 nm illuminated the Ag@oxides NPs, the temperature of media surrounding Ag@oxides NPs rapidly rose up, resulting in significant B16F10 cells death in Ag NPs-treated cells in vitro (p<0.01, t = 19.887). NIR laser irradiation decreased the tumor volume (tumor volume=(tumor length) ×(tumor width)2/2) gradually and completely ablated by 14 days treatment. The cells showed well tolerated to Ag@oxides NPs and the mice remained healthy over one-month period.

Conclusions: Ag@oxides NPs were demonstrated to be an efficient photothermal therapy agent for solid cancers by local delivery.

Keywords: 744 tumors • 608 nanomedicine • 589 melanoma