Application of F0F1­ATPase immuno­biosensors for detecting Escherichia coli O157:H7.

Escherichia coli (E. coli) O157:H7 is an important food­borne pathogen with a low infective threshold and high resistance to treatment. There are currently a number of detection methods available, however, the majority are time­consuming, complex and expensive, thus it is hard for these methods to be applied in routine detection. Therefore, there is urgent requirement to develop more sensitive, rapid and specific detective techniques. In the present study, an immuno­biosensor based on the interference of load to the F0F1­ATPase rotation, indicated by the fluorescence fluctuation, was constructed to detect O157:H7. The results demonstrated a good linear relationship (R2=0.9818) between antigen concentration (range, 102 cfu to 104 cfu) and the fluorescence intensity. The detection signals of the samples containing 102 cfu/well and 104 cfu/well E. coli O157:H7 were significantly stronger than the signal produced by the control sample (P<0.01). Due to its higher sensibility and simplicity when compared with the current methods applied, the results of the present study indicate a promising future for the application of this technique in detecting food source pathogens.

[Preliminary establishment of quantitative detection for luteinizing hormone based on superparamagnetic particles labeled immuno chromatography method].

OBJECTIVE: To develop a quick quantitative detecting method for luteinizing hormone(LH) based on superparamagnetic particles labeled immunochromatography technology. METHODS: Magnetic particles were catalyzed by EDC/NHS, LH monoclonal antibody were coupled with magnetic particles, another antibody were coated with the NC membrane, established a quantitative detecting method combined sand wish assay format with immunochromatography. The performance of this method was evaluated by linear range, precision, accuracy, specificity and stability. Detecting the serum sample that were tested by chemiluminescence immunoassay (CLIA) which was high credibility to verify the reliability. RESULTS: The reaction time of LH antibody coupled magnetic particles, LH and LH antibody coated in nitrocellulose membrane was 20 min; the coefficient of variation (CV) values for low, median, high were 8%-12%, the bias was less than 10%, recovery rate was 90%-120%, the minimum detection limit was 0.63 mIU/ml, no obvious cross reaction with human chorionic gonadotropin (HCG), thyroid stimulating hormone (TSH), follicle-stimulating hormone (FSH). Test results of clinical sample had good correlation with CLIA (R² =0.96, P<0.05). CONCLUSION: The superparamagnetic particles labeled immuno-chromatography method is simple and rapid, and is expected to become a direction in the development for point-of-care test (POCT) quantitative detection of micro components in biological sample.