A Ratiometric Electrochemical Sensor with Integrated Probe for the Assay of α-glucosidase Activity and Screening of Its Inhibitors

In this paper, we utilized an integrated electrochemical probe which consist of two redox groups instead of two redox molecules, the integrated probe simultaneously provided referenced signal and target responded signal. Combining with merits of enlarging the electroactive surface area and promoting the electron transfer of carbon nanohorns modified electrode, a new ratiometric electrochemical sensor for the assay of α-glucosidase and its inhibitors was fabricated. The ratiometric signal enabled the detection of α-glucosidase in a range of 0.001–0.016 U/mL with a detection limit of 0.00056 U/mL, which is lower than most of the existing methods. Furthermore, two α-glucosidase inhibitors, acarbose and mulberry bark, were used to assess the feasibility of screening potential anti-diabetic medicine, and the IC50 values of 0.55 mM and 3.38 mg/mL were obtained respectively. Thus, our proposed sensing strategy broadens the way for the design of novel ratiometric electrochemical sensors, and greatly extended the application of electrochemistry in medical analysis.