Study On The Miniaturized Spreeta SPR Immunosensor For The Detection Of E. Coli O157:H7

Escherichia coli O157:H7 is one of highly harmful foodborne disease-caused bacteria for the probability of epidemic outbreak and the danger of infection. It is in dire need of simple, accurate and rapid methods for their detection, since the traditional culture method is time consuming and labor-intensive. Various kinds of new detection methods were presented in details in this thesis, according to the the advantages of Spreeta SPR biosensor, the combination of Spreeta SPR biosensor and cell disruption technique was chosen for studies.The main contents and results of this thesis were as follows:(1) Different concentrations of glucose were used to assess the Spreeta SPR biosensor, the linear correlation coefficient (R) between refractive index and series of glucose concentrations was close to 1, which showed that the biosensor performance was quite well.(2) Following the RI response of the streptavidin and biotin-labeled antibody immobilization, it showed us the high repeatability of the Spreeta SPR biosensor, and the limit of detection (LOD) was 3×106 cfu mL-1 for detection of E. coli O157:H7.(3) The limit of detection for E. coli 0157:H7 was 3×105 cfu mL-1 based on BIACORE SPR immunosensor, as the same of that based on ELISA, it showed that the sensitivity was needed to be improved.(4) Cell disruption technique was used in this study, the limit of detection has been improved to 3×104 cfu mL-1 after cell disruption, with R2 of 0.98, which showed that Cell disruption technique leaded to a lower LOD.(5) E. coli DH 5a and Listeria were used to study the specificity of the SPR biosensor, and the resultsshowed that the SPR biosensor had high combination with on the target bacteria, and very low non-target adsorption.