Study Of Non-enzyme Potentiometric Glucose Sensors Based On Diboronic Acids

In recent years, with the continuous increase of the number of diabetics, considerable attention has been put to the treatment and diagnosis of diabetes. Researcher has been developing novel and efficient glucose sensors for diagnosis of diabetes for decades. However, the currently most widely used blood glucose meter is an amperometric glucose sensor. As this glucose sensor is sensitive to the activity of glucose oxidase, the development of non-enzymatic glucose sensor becomes the new frontier for diagnosis of diabetes. In this paper, based on the boronic acid compounds, which can recognize saccharides, and the DFT theoretical calculations, we designed and synthesized a series of diboronic acid compounds. To set up a non-enzyme potentiometric glucose sensor, we used the stable diboronic acid as the recognization molecule of glucose instead of the unstable glucose oxidase and combined with the characteristics of boronic acid that can induce anion potentiometric response on TDDA+Cl--doped polymeric liquid membrane electrodes. In addition, we investigated the selectivity, sensitivity and potential applications of this glucose sensor. The works described in this thesis are as follows:1. We developed a new polymeric liquid membrane electrode of potentiometric glucose sensor based on a diboronic acid for glucose recognition. Based on the fact that the boronic acid can bind 1,2-or 1,3-diols to form boronate esters and with the help of DFT calculations, we designed and synthesized a series of diboronic acids, namely DBA, DBA1 and DBA2. We explored the photophysical and electrochemical properties of these diboronic acids and the formed boronate esters when react with glucose. After optimizing the recognition molecules, the concentration of recognized molecules and pH of buffer solution, we selected 10-5 M DBA and pH 8.0 phosphate buffer solution as the optimal conditions for testing glucose. The detection limit of this highly selective and stable potentiometric glucose sensor is 0.2 mM and the linear range of 1-100 mM. This potentiometric sensor was applied in the actual blood detection and the results are consistent with the commercial blood glucose meter. This new novel method for glucose detection provides a new way of thinking for the determination of glucose in clinical medicine.2. We developed a new solid contact electrode of potentiometric glucose sensor based on the diboronic acid for glucose recognition. We studied the effects of the solid contact ion selective electrodes which used conductive polymer poly(3-octylthiophene) and C6o as ion to electron tranducer layers and blank tranducer layer of solid contact ion selective electrodes. We used the DBA as recognition molecule and TDDA+Cl--doped polymeric liquid membrane as the sensitive membrane. The tranducer layer will convert the changes of glucose concentration to electrical signals to achieve the concentration of glucose indirectly. This research broke through the disadvantages of traditional ion selective electrodes with internal solution. We optimized conductive material and established a new type of solid contact electrode potentiometric glucose sensor.This research provides a new method for the development of portable and miniature glucose sensor.