石墨烯量子点构建“off-on”荧光传感器检测脂肪酶活

In this paper, with high fluorescence efficiency graphene quantum dots (GQDs) as sensing elements, GQDs' lipase fluorescence sensor was designed. When there is presence of Hg2+, Hg2+ could adsorb on the surface of GQDs by electrostatic attraction, which quenched the fluorescence of GQDs; lipase and its substrate mercaptoacetic acid methyl ester (METG) were added, lipase could hydrolyze its substrate to generate thioglycolic acid (TGA), which resulted in a stronger binding force between TGA and Hg2+, so that Hg2+ released from the surface of GQDs. The fluorescence of quenched GQDs was restored, and the intensity of fluorescence recovery was related to the activity of lipase, so it can be used to quantitatively detect lipase activity. Under the optimal conditions, the linear range of the lipase is 0.05~1.6 mg/mL, and the detection limit is 2.77×10-4 mg/mL. The activity of the other four commercial lipases are determined by the method. The experimental results are consistent with the results of the titration assay. In addition, compared with the traditional colorimetric method, this method which is simple and convenient has higher sensitivity and selectivity, and can be used for high throughput and real-time detection of lipase activity.