The Application Research Of Biosensors Based On Graphene Oxide

For the past few years, nano materials has showed a broad application prospect in biology, chemistry, medical science and other fields because of its special physical and chemical properties. It has become a hot topic for researchers that using nano materials as carrier of fixed molecular recognition material so as to make biological sensors. Nano materials are of many excellent properties such as good biological compatibility, electric conductivity, high specific surface area, etc. Graphene is the basic unit of the other graphite of carbon materials. The carbon atom of graphene is hybrid sp2, and the π-π conjugate structure in a wide range can makes electronic move freely in the crystal, which leads to the graphene has a much excellent electron transport ability. Owing to the excellent electrical, mechanical and thermal properties, graphite has a broad application prospect in the field of composite materials, electronic device equipment, super sensitive sensors, super capacitor, fuel cells, lithium ion batteries, biological detection, drug release, etc.We can get the oligonucleotide sequence which combines with non-nucleic acid target molecules by the way of high affinity and high specific binding through SELEX technology, and choose the obtained oligonucleotide sequence as appropriate gametes. As a result of the development of SELEX technology, we obtained the appropriate gametes which have high affinity and specificity with small molecular, peptide, protein, even the entire cell. The SELEX technology shows a wide application prospect in the field of basic research, clinical diagnosis and treatment, new drug screening and any other domains because of its wide range of target materials selection and high affinity and strong specificity of obtained adaptorprotein. The selective aptamers by SELEX technology have high affinity and specificity with target materials similar to the antibodies. However, compared with the antibody molecules, oligonucleotide adapters have small molecular weight and simple structure to ensure the accuracy of the synthesis and easy connection in modified other molecules, such as fluorescent element, biotin,etc. At the same time, the aptamers will degenerate, repeat and have high speed, that can use repeatedly and preserve for a long time. Based on such advantages of the aptamers, there are irreplaceable advantages taking the appropriate gametes as recognition element of biological sensors or making biological sensors with it.Ochratoxin A has kidney toxicity, liver toxicity, immune toxicity, teratogenic toxicity and carcinogenicity to many kinds of animals. According to the report, the crops’pollution of Ochratoxin A is serious in the global scope, it exists widely in cereal (mainly wheat, barley, corn and oats), beans, peanuts, spices, dried fruit and coffee beans, and we have also detected OTA in beverages (such as beer, wine and grape juice). As people pay high attention to the health and security of food, we take the detection and control of Ochratoxin A seriously all over the world. There are many traditional test methods such as thin layer chromatography, high performance liquid-fluorescence method, capillary electrophoresis-diode array method, liquid-mass spectrometry league usage and colloidal gold immune chromatography technology, etc. These traditional methods have the weakness of high cost and long time, but the content of Ochratoxin is generally very low, thereby establishing a simple, sensitive and cheap detection method is very urgent. For that reason, we mainly detected Ochratoxin A through fluorescence method based on the basement of oxidation graphite and has builded glucose biological sensors by oxidation graphite. And we have done some concrete research content as follows:1:As we all know, oxidation graphite has the ability of fluorescence extinction for the fluorescent aptamers, but it does not occur in the macromolecule which combines with ordinary aptamers and Ochratoxin A. So we can realize the specificity detection of Ochratoxin A based on such features. Firstly, choose the appropriate base of fluorescence destroy, find out the best determination conditions and detect the target materials through the fluorescence enhancement in that conditions. Consequently, establish a new type of sensors about detecting Ochratoxin A. Furthermore, reduce the adsorption of Ochratoxin A with oxidation graphite by selecting the right protective agents in order to improve the sensitivity and accuracy of test method. And the sensor established by this method can test red wine or other real samples.2:Oxidizing the graphite and nickel salt with layer-layer assemble in glassy carbon electrode, electrochemical scanning to1.4V, restoring graphene oxide with one-step, and generate a new material through layer-layer assemble between graphene and nickel hydroxide. On account of large specific surface area and superior conductivity of graphite, this new material has better conductive performance than bare glassy carbon electrode, and will have a good application prospect.