Advances in biological imaging applications of fluorescent gold nanoclusters (invited)

In recent years, due to the unique advantages such as excellent fluorescence properties, ultra-small size, precise chemical structure and good biocompatibility, gold nanoclusters (AuNCs) have become a kind of emerging fluorescent nanoprobe of great concern. In order to promote the application of AuNCs in fluorescence imaging, researchers have been devoted to designing preparation strategies for various high-performance fluorescent AuNCs. Based on the continuous understanding of the structure and luminescence mechanism of AuNCs, strategies such as enhancing the fluorescence quantum yield and cellular uptake of AuNCs have been proposed and applied to enhance the cellular imaging ability of AuNCs. These strategies greatly improve their potential as fluorescent imaging probes. Furthermore, fluorescent AuNCs are also utilized in advanced fluorescence imaging technologies such as fluorescence lifetime imaging and multi-photon fluorescence imaging. In addition, AuNCs with near-infrared II fluorescence have greatly promoted their application for in vivo imaging recently. This article summarizes the preparation methods of fluorescent AuNCs probes, reviews strategies to improve the fluorescence cellular imaging ability of AuNCs, and introduces the latest progress in the application of AuNCs in fluorescence imaging and also the challenges and future developments in the field.