A cysteine-induced one-pot synthesis of Au nanoparticle chains with tuneable NIR absorption and application in photothermal-chemo cancer therapy

Abstract

A facile L-cysteine (L-cys) mediated one-pot green method is explored to prepare a chain-like Au nanoparticle (AuNP) assembly structure. In this method, the L-cys can be used as a morphology inducer to control the morphology of nanoparticles and as a template molecule to trigger the AuNP assembly to form 1D AuNCs. The formation of the assembly structure was dependent on the concentration of the L-cys. The obtained AuNCs represent significant absorption in the NIR region, which is tunable by adjusting the amount of L-cys and AgNO₃. The good photothermal conversion ability proves that the AuNCs can be used as a PTT agent in cancer therapy. Biocompatible mesoporous silica is further employed to coat the AuNCs, improving the biocompatibility and drug delivery ability. Doxorubicin (DOX) is loaded on AuNCs@mSiO₂ by adsorption and then is used for drug delivery and photothermal cancer therapy. Cellular and animal experiments reveal that AuNCs@mSiO₂@DOX exhibits a considerable tumor inhibition effect with the irradiation of an 808 nm NIR laser, reflecting that the AuNCs@mSiO₂@DOX could act as a promising candidate for photothermal-chemo synergetic cancer therapy.