One-pot synthesis of ultra-bright water-soluble gold nanoclusters for LAT1-targeted cancer cell imaging.

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 low luminescence quantum yield (QY), typically less than 10%, substantially restrict their applications, which still need to be addressed. Herein, we report the 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 a stabilizer and reducing agent, gold nanoclusters were one-pot synthesized with a tunable QY by simply adjusting the reaction temperature. Structural analysis indicated that the enhancement in the QY of the gold nanoclusters may be attributed to the binding of the imidazole ring and the carboxylic acid group of L-histidine to the gold core and an elevated proportion of Au(I) within the nanoclusters. Furthermore, due to the L-histidine modified on the gold core as the substrate for LAT1, the as-prepared gold nanocluster allowed for the specific targeting of cancer cells overexpressing LAT1, thereby promoting cellular uptake. LAT1-targeted fluorescence imaging of HeLa cells treated with the ultra-bright gold nanoclusters was demonstrated using LAT1 inhibitor-pretreated cells for comparison. Overall, our study not only provides a rapid and convenient synthesis strategy for gold nanoclusters with enhanced QY, but also exhibits potential application in LAT1-targeted cancer cell imaging.