Gold Nanoclusters-Indocyanine Green Nanoprobes for Synchronous Cancer Imaging, Treatment, and Real-Time Monitoring Based on Fluorescence Resonance Energy Transfer

Well-designed gold nanoclusters-indocyanine green nanoprobes (Au NCs-INPs) have been developed by the conjugation of Au NC assemblies with indocyanine green (ICG) for the therapeutic real-time monitoring based on fluorescence resonance energy transfer (FRET). The synthesized Au NCs-INPs demonstrated the improved cellular uptake and effective tumor targeting because of the enhanced permeability and retention effect and the gp60-mediated secreted protein acidic and rich in cysteine combined transport pathway, suggesting excellent dual-modal near-infrared fluorescence and photoacoustic imaging. Moreover, the simultaneous photodynamic therapy (PDT) and photothermal therapy (PTT) of Au NCs-INPs exhibited higher cancer cell killing and tumor removal efficiency than those of PDT or PTT alone. More importantly, a promising therapeutic monitoring strategy was performed based on FRET between Au NCs and ICG, suggesting that Au NCs-INPs could be utilized to evaluate the therapeutic response by real-time monitoring the change in Au NCs in fluorescence intensity together with ICG supersession. Therefore, Au NCs-INPs as a novel photosensitizer have great potentials for combined tumor imaging, therapy, and therapeutic monitoring in real time.