In this study, a new sensor for the fluorescence detection of guanosine and Mg 2+ ions using a “turn-off–on” mechanism was successfully constructed using 2-mercapto-5-nitrobenzimidazole (MNB) modified bimetallic molybdenum–gold nanoclusters (Mo-AuNCs). The method has minimal cost, excellent sensitivity, good selectivity, simplicity, and speed. After being excited at 390 nm, the MNB-Mo-AuNCs fluorescence emission peak was obtained at 531 nm. The addition of guanosine selectively reduces the fluorescence intensity of MNB-Mo-AuNCs and the turn-on mechanism recovers the quenched fluorescence in the presence of Mg 2+ . The limits of detection (LODs) for the guanosine and Mg 2+ ions using this approach were 1.43 and 0.10 µM, respectively. The fluorescence sensing technique based on MNB-Mo-AuNCs demonstrated exceptional performance for guanosine detection in biological samples. The method showed great reproducibility (relative standard deviation < 2%) and recovery ranging from 96.3% to 99.21% in plasma and serum samples indicating the method considerable potential for real-world applications.
Harshita et al. (Sun,) studied this question.