An innovative colorimetric sensing strategy was developed for the detection of glucose by the integration of glucose aptamer, glucose oxidase (GOx), and horseradish peroxidase (HRP), termed aptamer proximal enzyme cascade reactions (APECR). In the presence of glucose, aptamer binding enables GOx to catalyze glucose oxidation into H2O2 efficiently. Subsequently, the adjacent HRP catalyzes the oxidation of the peroxidase substrate, 2,2'-biazobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS2-), utilizing the generated H2O2, resulting in a distinct color change. In comparison to the free enzymes and the HRP-GOx system, APECR exhibited higher colorimetric signal. This approach achieved glucose detection within three minutes, which was significantly faster than previous methods. This method showed good sensitivity and selectivity with a limit of detection of 0.013 mM. Moreover, the practical utility of this strategy was verified by achieving rapid detection of glucose in clinical serum samples. Hence, the developed strategy has the advantages of simple operation and rapid analysis time for the detection of glucose in human serum.
Keywords: Colorimetric sensing method; Enzyme cascade reactions; Glucose aptamer; Glucose detection; Glucose oxidase; Horseradish peroxidase.
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