Fabrication And Performance Study Of Amperometric Glucose Sensors Based On Carbon Nano-materials

Glucose is the major component of carbohydrates in the lives, and it plays a vital role in sustaining metabolism. Blood sugar level in normal human bodies must be kept in a certain range, or it will lead to a series of diseases when the glucose content is too high or too low. Thus, monitoring the content of glucose in blood timely is very important to assess human’s health. At present, there are a variety of methods to detect glucose, and among these electrochemical sensors are widely used in clinical diagnosis, environmental monitoring, food industry and many other aspects because of their characteristics of simple operation, good selectivity, fast analysis speed. Nano-materials have developed rapidly in recent years, and many literatures have reported their application in the fabrication of chemical modified electrodes, and the nano-materials’introduction can further improve the performance of the glucose biosensor. This article studies three new glucose electrochemical biosensors based on the electrode modification materials such as single-walled carbon nanohorns, graphene, metal nanoparticles and so on, and the main contents are as follows:1. A novel non-enzymatic glucose electrochemical sensor was fabricated by dropping single-walled carbon nanohorns suspension on the glassy carbon electrode and then depositing copper nanoparticles. The glucose sensor had a good function of catalytic oxidation of glucose in alkaline medium. It was used to the determination of glucose at 0.35 V with a linear range of 0.04-12.56 mmol/L and a detection limit of 17 μmol/L (s/n= 3). The stability and reproducibility of the sensor are good, and it can eliminate interference from L-cysteine, ascorbic acid, dopamine and uric acid.2. Using chitosan to immobilize glucose oxidase, we abtained a glucose sensor based on glucose oxidase. Firstly, depositing gold nanoparticles on the glassy carbon electrode by cyclic voltammetry scanning; Secondly, dropping the mixed solution of single-walled carbon nanohoms and glucose oxidase on the surface of modified electrode; Lastly, glutaraldehyde was used to crosslink the glucose oxidase. Electrochemical tests showed that the sensor can catalyze oxidation of glucose with the presence of ferrocenemethanol as electron transfer mediator. The linear range for determination of glucose is 0.08-4.80 mmol/L, with a detection limit of 30 μmol/L (s/n= 3). In addition, the sensor can realize direct electrochemistry of glucose oxidase. Scanning speed and pH value were also investigated to evaluate their influence. The third generation of glucose biosensor is promising to establish on this basis of direct electrochemistry of glucose oxidase.3. We reported a novel amperometric glucose sensor based on Schiff reaction between amino and aldehyde group. Glucose oxidase (GOD) with aldehyde group and amination of graphene-nanogold composite material (rGO-Au) were covalently assembled on the glassy carbon electrode layer by layer alternately. To explore the sensor’s electricity catalytic oxidation towards glucose, electrochemical impedance analysis, cyclic voltammetry and amperometric i-t curve were used to test multilayer membranes electrode. The current response was good proportional to the concentration of glucose, and the sensor had good reproducibility and stability.