Study On Current Model Glucose And Immune Sensor Based On Nanomaterials

Modern medical science believes that cancer is a systemic disease, the relevantinformation demonstrates that most tumors like70%-80%or even90%can be cured ifdetected in time, so the key to improve the recovery rate of cancer patients is the earlydiagnosis and prompt treatments of tumors. The study of early diagnosis method has becomeone of the important frontiers for the cancer researches on prevention, and the electrochemicalbiosensor is a tool which has a simple, convenient operation and can complete thedetermination in a short time. The electrochemical biosensor is a device which combines thesensor technology of high sensitive and selectivity with specific immune response in order tomonitor the reaction of antigen and antibody. As the specific reaction of antigen and antibodyrelated with the tumor, the combining information of them is turned into the electrochemicalsignal which can be detected, in order to achieve the detection of tumor cytokines accurately,rapidly and sensitively.From the fix of the biological activity substances, this thesis builds a variety ofbiosensors combined with the multi-functional nano-materials in the field of today’s materialscience. The research is mainly divided into five parts as follows:1. This section presents an overview of the definition of the electrochemical biosensor,the classification of biosensor, immunoassay, immune sensor and its classification, theapplication and development trends of immune sensor; introduces the applications ofnano-materials in the immune sensor as well as the applications of immune sensors in thedetection of tumor.2. A sandwich-type electrochemical immunosensor for the ultrasensitive detection of thesalbutamol (SAL) antigen based on sodium dodecylbenzene sulfonate-functionalizedgraphene sheets (SDBS-GS), Pd nanoparticles in functionalized SBA-15(Pd@SBA-15) andionic liquid (IL) is described. The primary SAL antibody (Ab1) can be covalently attached tothe sulfonic groups of SDBS-GS through the amines of Ab1with an acyl chloridecross-linking reaction. Pd@SBA-15was prepared by adsorption of H2PdCl4onto the SBA-15surface; the adsorbed H2PdCl4was then reduced to Pd nanoparticles with sodium borohydride.Pd@SBA-15was conjugated to the secondary SAL antibody (Ab2) through glutaraldehyde. IL was added to the mixture of Pd@SBA-15and Ab2to promote electron transport. Thesynergistic effect between IL and Pd@SBA-15retained the bioactivity of Ab2. The sensitivityof the sandwich-type immunosensor using Pd@SBA-15/Ab2/IL for the detection of SAL wasmuch higher than those that used either SBA-15/Ab2or Pd@SBA-15/Ab2. Under optimalconditions, the electrochemical immunosensor exhibited a wide working range from0.02to15.0ng/mL with a detection limit of7pg/mL. The precision, reproducibility and stability ofthe immunosensor were acceptable. The proposed strategy could be easily extended tofabricate immunosensors for other tumor markers.3. With the good properties of strong adsorption ability, nice biological compatibility andfine catalytic efficience of the nano-materials, they are applied in the electrochemicalimmunoassay sensor in order to improve the sensitivity of the detection, shorten the responsetime, achieve the real-time detection of targets as well as extend the service life of someenzyme electrodes to reduce the cost. Among them, graphene is widely used in theelectrochemical biosensors with its nice electrical conductivity, big BET specific surface areasand excellent capacitance properties. In this section, the nitrogen-doped graphene sheets(N-GS) and Pt-Pd in functionalized GS (Pt-Pd@GS) are used to build a sandwich-typeelectrochemical immunosensor of high sensitivity, good selectivity, good stability, stronganti-jamming capability. It is measured that the linear range of the diethylstilbestrolantigen(DES) is0.01ng/mL~14.0ng/mL, the detection limit is5pg/mL withchronoamperometry under the optimal experimental conditions.4. As the importance of glucose in biochemistry, clinical research and food analysis,accurate and rapid detection of glucose has attracted people’s attention. In this study, the mixof GS, gold nanoparticles and glucose oxidase (GOx) are incubated to form a nanocomposite,the GOx is fixed on the surface of the modified electrode using thionin as an electronmediator, which improves the immobilization of enzyme, a glucose sensor system with goodperformance is made. With a wide linear detection range (1.0~10.0mmol/L) and lowerdetection limits (0.038mmol/L), the sensor has a satisfied selectivity, reproducibility andstability. The advantages of the glucose sensor with simple building process and theultra-sensitivity may provide a potential application for clinical diagnosis and biochemicalresearch. 5. Breast cancer is one of the most common malignant tumor of women, in accordancewith the relevant statistics, the incidence of breast cancer accounts for7-10%of a variety ofthe malignant tumors. It is a common malignant tumor happened in the epithelial tissue of thebreast associated with genetic, it is one of the most common malignant tumors which canseriously impact on women’s health and even threaten the life, and the three tumor markers ofcarcinoembryonic antigen(CEA), carbohydrate antigen CA125and CA153are closely relatedwith breast cancer, it has a very large significance on the early diagnosis of breast cancer withthe three joint detection. In this work, a three-channel screen-printed electrode is designed andproduced, the graphene is firstly modified on the three electrode in order to access and fix theantibodies of CEA, CA125and CA153. The two anti-tag is discussed by the method of adouble antibody sandwich immunoassay. The markers are M-Pt NPs and Ab2,with H2O2in thebase solution, so that the electrochemical signal of the immunosensor has been greatlyenhanced, and the multi-channel immunosensor system obtained has excellent performance,high sensitivity and it can also detect the three tumor markers of breast cancer at the sametime.