Research On Nano Electrochemical Immuno-biosensor For Pathogenic Bacteria Detection

Pathogens common in life are a great threat to human and animal health,it is extremely important to achieve rapid and accurate detection.At present,there are many methods for detecting them.Each method has its own advantages and disadvantages.The method used in this dissertation is electrochemical biosensor method with short response time,Two typical pathogenic bacteria were selected as the target: E.coli O157:H7 and Staphylococcus aureus,the main works of this dissertation were as follows:1)Firstly,the appropriate size of the micro interdigitated electrodes were designed by COMSOL simulation,and the nano-Zn O was electrochemicaliy deposited on the surface of the micro interdigitated electrode.Then the surface of the deposited layer was modified by(3-aminopropyl)-triethoxysilane(APTES),glutaraldehyde(GA)etc.Then the streptavidin was modified on the surface of nano-Zn O,its affinity with biotin was used to immobilize the pathogenic antibody on the sensor surface,and the bovine serum albumin(BSA)was used to block the nonspecific binding sites.2)The different types of sensors were characterized and then the construction and modification of sensors were characterized by cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),field emission scanning electron microscopy(FESEM),laser raman spectroscopy and infrared spectroscopy.The morphology,structure and surface modification composition of the sensor were analyzed,and the construction of the sensor was determined.The experiment and analysis show that the sensor is well constructed.3)At last,two kinds of sensors were used to detect the different concentrations of E.coli and S.aureus respectively.The Bode and Nyquist diagrams obtained from the experiment were analyzed by the equivalent circuit.The experimental results showed that the two kinds of sensors had a large detection range,good performance and practicability,and have the potential for practical use.The detection limits of E.coli and S.aureus obtained by equivalent circuit and mathematical probability analysis are 40cfu/m L and 43cfu/m L respectively which meet the national standards.Figure 34;Table 15;Reference 62...