Assembly of protein-directed fluorescent gold nanoclusters for high-sensitivity detection of uranyl ions.

Uranium is a key element in the nuclear industry, whose accidental release causes health and environmental problems. In this paper, a protein-directed fluorescent sensor with aggregation-induced emission characteristics (gold nanoclusters@ovalbumin, AuNCs@OVA) was synthesized for the detection of UO with high sensitivity and selectivity. The sensor exhibited good fluorescence stability, and its fluorescence intensity could be selectively enhanced by UO. Based on FT-IR and XPS analyses, the increase in fluorescence intensity of AuNCs@OVA after the addition of UO was attributed to aggregation induced by the complexation between UO and the amino, carboxyl, hydroxyl, and phosphate groups of ovalbumin. The detection limit was determined to be 34.4 nM, and the sensor showed excellent ion selectivity for UO. In combination with a smartphone program, the sensor could realize the real-time detection of UO in a quantitative and portable way.