Theranostic gold cluster nanoassembly for simultaneous enhanced cancer imaging and photodynamic therapy

As one of near-infrared (NIR) fluorescent (FL) nanoprobes, gold nanoclusters (Au NCs) are delicated to passive-targeting tumors for NIR FL imaging, but which easily cleared by the kidneys for the small size (<1.5 nm). Herein, the well-defined gold clusters nanoassembly (Au CNA) was synthesized by the self assembly of Au NCs based on protein cross-linking approach. The as-prepared Au CNA demonstrated highly effective cellular uptake and precise tumor targeting compared to that of Au NCs. Moreover, with the irradiation of 660 nm laser, Au CNA generated largely reactive oxygen species (ROS) for photodynamic therapy (PDT). In vitro and in vivo PDT revealed that Au CNA exhibited largely cell death and significantly tumor removal at a low power density of 0.2W/cm(2). It could be speculated that the laser-excited Au CNA produced photon energy, which further obtained electron from oxygen to generate radical species. Therefore, Au CNA as a photosensitizer could realize NIR FL imaging and NIR laser induced PDT. (C) 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.