| Glucose is the main component of carbohydrate in plant and animal, it is of vital significance to monitor blood glucose for evaluating people’s health. With the improvement of people’s living standard, all sorts of “wealthy diseases” also follow, diabetes is one of the most typical diseases. As a result, the World Health Organization and the International Diabetes Federation passed a resolution to observe “World Diabetes Day” every November fourteenth, its aim is to cause the global awareness of diabetes. The main features of diabetes include that blood glucose concentration is higher than the normal range of 4.4- 6.6 m M(80- 120 mg/d L), accompanying by polydipsia, polyuria, polyphagia, weight loss and other symptoms. The fluctuations of blood glucose will greatly lead to blindness, kidney failure, heart disease and stroke chronic complications of diabetes. At present, the treatment of diabetes is mainly the insulin injection based on the frequent detection and controlling of blood glucose concentration. It is of significant importance to continuously monitor blood glucose diabetes patients. There is still plenty room for the research of improving sensitivity, detection range, stability and anti-jamming of glucose sensors.Glucose sensors are divided into enzyme glucose sensor and non-enzymatic glucose sensor depending on whether it contains glucose oxidase(GOD). GOD is easy to lose its activity because of environmental influence by temperature, humidity and p H value. Enzyme glucose sensor is restricted by certain conditions in the practical application because of the problems of stability and reproducibility. More and more attention has been paid to non-enzymatic glucose sensor based on the advantages of good stability, lower detection limit, higher sensitivity and higher current response. Nanomaterials show a good catalytic activity, unique physicochemical properties and biological compatibility, which are widely used in biosensor construction. So far, nanocomposite materials, transition metal nanoparticles, carbon nanotubes(CNTs) and magnetic nano-materials, with which electrocatalytic properties of new materials were successfully used to construct non-enzymatic glucose sensor.Taking the aforementioned into consideration, copper nanowires, porous palladium nanotubes, palladium nanoflowers, palladium nanocubes and palladium nanooctahedrons were synthesized by using hydrothermal method in this thesis. Composition and morphology of as-prepared materials were characterized by transmission electron microscopy(TEM), scanning electron microscope(SEM), high resolution transmission electron microscopy(HRTEM), atomic force microscopy(AFM) and X-ray diffraction(XRD). Non-enzymatic glucose sensors were constructed with these materials and their electrocatalytic properties were investigated. The main research contents and conclusions are as follows:1. Flexible and uniform copper nanowires were synthesized by hydrothermal method, which were loaded on a glassy carbon electrode(GCE) as the sacrificial agents and placed in the chloride palladium sodium solution after drying under vacuum under the condition of moderate water bath to obtain porous palladium nanotubes. Non-enzymatic glucose sensors were constructed with as-prepared palladium nanotubes to detect concentration of glucose, which show high sensitivity, low detection limit and good selectivity. The catalytic performance of the glassy carbon electrode modified with copper nanowires was compared and not as good as that of palladium nanotubes. The detection range is 5 μM ~ 10 m M, the detection limit is 1 μM(S/N =3) and the linear correlation coefficient is above 0.99 when the operating voltage is at 0.4 V. This method is simple and environmentally friendly, In addition, as-prepared materials exhibit good catalytic properties, which can be used in the fuel cell and other fields.2. The preparation of single crystal porous palladium nanoflowers, palladium nanocubes and palladium nano-octahedrons and their catalytic properties as non-enzymatic glucose sensors were studied. Composition and morphology of as-prepared materials were characterized by TEM, HRTEM and XRD, the catalytic ability of the three kinds of palladium nanoparticles with similar and uniform size were compared. The experimental results show that catalytic activity of porous single-crystalline palladium nanoflowers and that palladium nanocubes with enriched {100} facets are better than that of palladium nano-octahedrons with enriched {111} facets. Due to the large specific surface area and high index crystal surface, the catalytic activity of the single crystal porous palladium nanoflowers is the best, which also has a good stability and anti-disturbance ability. The detection range is 0.05 ~ 6 m M(R2 = 0.9984), and the detection limit is 1 μM(S/N = 3) when the operating voltage is at 0.4 V.3. In order to further explore the performance of the glucose sensors constructed with porous materials, we turned steel needles with 15 μm gold layer into porous structure by electrochemical method, which increased their specific surface area and improved the catalytic properties of glucose. The purpose is to replace the gold plating platinum, thus reducing the cost for industrialization. Porous gold needles were prepared by electrochemical method in the benzyl alcohol solution of zinc chloride according to the literatures. The as-prepared porous gold needles were characterized by XRD and SEM for the future use of glucose biosensor. |
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