Photochemical synthesis of fluorescent Au-16(RGDC)(14) and excited state reactivity with molecular oxygen

Aqueous metal nanoclusters have emerged as effective materials for biomedical imaging and therapy. Among them, gold nanoclusters (AuNCs) have been widely studied due to their unique electronic structures. These nanoclusters are often optically impure, comprising a mixture of fluorescent clusters with different metal/ligand compositions. The polydispersity of nanoclusters makes it challenging to isolate the most stable structure, and poses further risks for eventual clinical applications. Herein, Au16L14 clusters are reported which are optically pure as assessed by fluorescence excitation-emission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis. The reactivity of their excited state with molecular oxygen was also probed, demonstrating that the Au16L14 clusters generate type I reactive oxygen species (ROS), which can make them effective sensitizers for photodynamic therapy.

Automated summary

Aqueous gold nanoclusters (AuNCs) have potential applications in biomedical imaging and therapy due to their unique electronic structures. However, their optical impurity and polydispersity pose challenges for isolation of the most stable structure and potential clinical applications. This study reports optically pure Au16L14 clusters, assessed by fluorescence excitation-emission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis. The reactivity of the excited state with molecular oxygen was also investigated, showing that Au16L14 clusters generate type I reactive oxygen species (ROS), making them effective sensitizers for photodynamic therapy.