One-Pot Synthesis of Ultra-Bright Water-Soluble Gold Nanoclusters for LAT1-Targeted Cancer Cell Imaging

Abstract

Gold nanoclusters have emerged as promising fluorescent nanomaterials for biomedical applications due to their special properties such as low toxicity, excellent photostability and biocompatibility. Nevertheless, the disadvantages of lower luminescence quantum yield (QY), typically less than 10 %, substantially restricts their applications, which still need to be solved. Herein, we reported a fabrication of ultra-bright water-soluble gold nanoclusters and their application as fluorescent probes for LAT1-targeted cancer cell imaging. Taking advantage of L-histidine as both the stabilizer and reducing agent, the gold nanoclusters were one-pot synthesized with tunable QY by simply adjusting reaction temperature. The structural analysis indicated that the QY enhancement of gold nanoclusters might be attributed to both the binding of the imidazole ring as well as carboxylic acid group of L-histidine to gold core and the elevated proportion of Au(I) in the nanoclusters. Furthermore, due to the L-histidine modified on gold core as the substrate of LAT1, the as-prepared gold nanocluster allowed for specific targeting toward cancer cells overexpressing LAT1, thereby promoting the cellular uptake. LAT1-targeted fluorescence imaging of HeLa cells stained by the ultra-bright gold nanoclusters was demonstrated by using LAT1 inhibitor pretreated cells for comparison. Overall, our study not only provides rapid and convenient synthetic strategy for gold nanoclusters with enhanced QY, but also exhibits a potent potential for LAT1-targeted cancer cell imaging.