Fluorescence-enhanced detection of sulfide ions through tuning the structure-activity relationship of gold nanoclusters

The concentration of S2 is a vital environmental indicator for evaluating the quality of source water, surface water, and wastewater, and it has a significant impact on biological systems, particularly human health. Therefore, it is crucial to detect S2 selectively and sensitively. In this study, we developed a simple and rapid one-pot method to prepare a gold nanocluster (BSA-AuNCs) probe for fluorescence-enhanced detection of S2 toxemia and analyzed the morphological characteristics of BSA-AuNCs and its complex with S2 using various characterization techniques. The principle of the sensor is based on the interaction between S2 and amino acids in the BSA molecular layer coated with gold clusters, regulating the rigid structure changes of gold clusters, and thus affecting the fluorescence properties of gold clusters. Through the specific interaction mechanism between proteins and gold-sulfur ions, this sensor exhibits excellent selectivity. It responds to S2 in the range of 0 to 30 mu M, with a detection limit of 0.395 mu M, and shows no response to other heavy metal ions, anions, or amino acids. The sensor is environmentally friendly, simple to operate, has strong practicability, good precision, and recovery rate, and has potential application value in biological and environmental fields.