A triple-emission ratiometric fluorescence sensor based on carbon dots-Au nanoclusters nanocomposite for detection of tetracycline

The accumulation of excess tetracycline (TC) antibiotics in the environment are seriously dangerous to ecosystems and human health. Herein, a well-defined triple-emission ratiometric fluorescence sensor was developed for the detection of TC by using the carbon dots hybridized glycoprotein ovalbumin stabilized Au nanoclusters nanocomposite (CDs-AuNCs). The construction of this triple-emission sensing method was simple and didn’t require assistance of complex coupling reagents. Upon TC recognition, the intrinsic green fluorescence at 520 nm of TC was significantly intensified by OVA sensitization, whereas the blue and red fluorescence (at 423 and 660 nm) of CDs-AuNCs sensor were gradually quenched through the inner filter effect and dynamic quenching process. Under optimized conditions, the CDs-AuNCs sensor exhibited a wide linear response for TC in the range of 0.5–40 μM with a detection limit down to 0.056 μM, and the corresponding fluorescence colors changed from blue purple to pink, orange red, yellow, and finally yellow green under a UV lamp, which can be easily discerned by naked eye. Moreover, the sensor showed excellent selectivity for TC, and was successfully applied in real water samples. The simple, rapid, reliable and visible CDs-AuNCs sensor proved to be potentially applicable for TC determination in complicated matrices.