Bright and Renal-Clearable Au Nanoclusters with NIR-II Excitation and Emission for High-Resolution Fluorescence Imaging of Kidney Dysfunction

Real-time monitoring of kidney dysfunction in vivo is of great significance to the diagnosis of renal diseases and the preservation of human health, which can be achieved by second near-infrared (NIR-II) fluorescence imaging. However, the development of NIR-II fluorescence imaging for the study of kidney dysfunction has been impeded by a lack of renal-clearable NIR-II luminescent materials with good optical properties. This study synthesized renally clear gold nanoclusters (Au NCs) with both NIR-II excitation and emission for the first time. Imaging with NIR-II light excitation offers deep tissue penetration, high resolution, and a high signal-to-background ratio. Additionally, the developed Au NCs have quantum yields as high as 1.4–2.0%, nearly 10-fold higher than that of previous renal clearable NIR-II emitting materials. These salient merits allow Au NCs to realize high-resolution fluorescence imaging, as well as monitoring of kidney dysfunction induced by renal ischemia–reperfusion and unilateral ureteral obstruction. Our findings provide new candidate materials for NIR-II fluorescence imaging and a powerful tool for high-resolution and accurate imaging of kidney diseases.