Protein-Localized Bright-Red Fluorescent Gold Nanoclustersas Cyanide-Selective Colorimetric and Fluorometric Nanoprobes

摘要

Herein, we describe a bright-red-emitting ovalbumin-protected gold nanoclusters (OVA–AuNCs) that were prepared and applied as a luminescent probe for a simple, rapid, and highly sensitive determination of cyanide ions (CN^– ions) based on an emission quenching and colorimetric method. Initially, an intense red-emissive fluorescence of the OVA–AuNCs successfully disappeared upon the addition of CN^– ions. The resultant emission-quenching process involved CN^– ions etching the OVA–AuNC surface, which produced AuCN2^– complexes in the presence of ambient oxygen. Under optimized experimental conditions, the relative emission intensity is inversely relative to CN^– ion concentrations ranging from 5.00 × 10^–7 to 75.00 × 10^–7 mol/L with a linear correlation coefficient of 0.9932. Furthermore, OVA–AuNC-based optical detection systems on both colorimetric and fluorometric assays were tested, which expose highly sensitive and specific determination of CN^– ions, and it is easily visualized by the naked eye (day light and UV light). Because of the distinct Elsner reactionbetween Au atoms of OVA–AuNCs and CN^– ions,the recent nanoprobe offered ultrasensitivity and good selectivitywith the lowest limit of detection value of 68.00 × 10^–9 mol/L. In addition, this fluorescence “turn-off” CN^– ion detection method was executed in real water samples.The demonstrated route of OVA–AuNC preparation is extremelyeasy and quick, making the proposed selective and sensitive CN^– ion sensing assay based on the fluorescence responseof the OVA–AuNCs for numerous practical applications.