The Research Of Nonenzymatic Glucose Sensors For Point-of-care Test

In recent years,point-of-care test(POCT)has shown great developing prospect in medical examination,for example,commercial glucose meters have been common in daily life.With the iteration of sensors,much more advanced technology is desired to achieve more effective and sensitive determination.According to many researches,the nonenzymatic glucose sensors are expected to replace the enzyme-based test strips and sensors.The advantage of the nonenzymatic glucose sensors lies in that the catalytic oxidation process can be completed without the assistance of electron transfer medium,which is promising to improve the sensitivity and stability of the sensor.Meanwhile,the modification of the electrodes is beneficial for promoting the efficiency and sensitivity of detections in many body fluids,such as the glucose concentration in urine,sweat and other body fluids,which extends the usage scenarios and provides the users with convenient experience.However,numerous researches have reported that nonenzymatic glucose sensors require preestablished reaction environment or complete the whole process with complex multiple-potential control.Therefore,considering the principle of electrochemistry and the current development status of nonenzymatic glucose sensors,bipolar electrodes are introduced to simplify the complex multiple potentials control and pretreatment process,which is the innovation compared with the former research.At the same time,the sensors are designed to apply in different usage with their characteristics and some detailed problems are solved specifically.This research is combined with those parts:1.A nonenzymatic glucose sensor is reported,which is designed on the basis of a multiple potential application for the electrochemical analysis of urine glucose in a urinal.For the detection,three potential steps are applied on an Au working electrode,including a high negative pretreatment potential step to produce a temporary alkaline condition on the electrode,a minor positive potential step for electrocatalytic oxidation of glucose in the alkaline condition and a high positive potential step for the self-cleaning of the working electrode.For improving the selectivity of the sensor,the Au electrode is modified with perfluorinated sulfonic acid.The sensor is integrated in a smart urinal so that real human urine glucose level is monitored,and the test result can also be uploaded in real time to a smartphone App via Bluetooth.2.A nonenzymatic glucose sensor based on bipolar electrodes(BPEs)with the assistance of driving electrodes is developed.Different from conventional BPE-based electrochemical analysis,the hydrogen evolution reaction on the driving electrode is utilized to create an alkaline condition for electrocatalytic oxidation of glucose on the Au BPE.With the principle of BPE,the nonenzymatic glucose detection can be carried out with single potential and simple instrument.In contrast with the sensor based on three-electrode system,problems from multiple-potential step used for nonenzymatic glucose sensing are addressed with the help of bipolar electrodes.A fully integrated device for nonenzymatic glucose sensing is developed.Urine glucose is tested by the device,and the test results are compared with those obtained from a standard glucose test kit.3.The bipolar electrodes based nonenzymatic glucose sensor is designed on test strips with the assistance of screen-printed electrodes.The sensor in Chapter 3 is transplanted and miniaturized in this way.The screen-printed electrodes are modified with electrodeposition to achieve the same function in the sensor mentioned above.Some parameters are optimized to fit the new system and some tests are performed to prove the efficiency of this scheme.The purpose of this research is to explore the application of bipolar electrodes sensor in miniaturization or wearable devices.In summary,the innovation of this project is the introduction of bipolar electrodes for the nonenzymatic glucose sensors.Precisely,the driving electrodes of bipolar electrodes,which are easily ignored,are the most attractive originality.The alkaline condition,which is required in nonenzymatic glucose sensing,is created by the driving electrodes.This optimization enriches the uasge of driving electrodes and follows the idea of clean chemistry.