Application Of A Fiber Optic Biosensor In Detection Of Pathogen And Its Antibody

The project focuses on establishment of a plateform of a fiber optic biosensor for detecting pathogens and their antibodies sensitively and specifically on site, taken Yersinia pestis as a model target.The detection platform based on the biosensor FOB-3 was set up by devising the biosensor system in collaboration with Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences. Optimal condition for detecting pathogens and their antibodies rapidly, sensitively and specifically was obtained by processing data, evaluating stability of the FOB-3 and variability in fiber probes, and optimizing the experimental parameters. In the optimal condition, Y. pestis and its F1 antigen were detected with the FOB-3, and then 39 tissues of mice were investigated by the biosensor. After analysis of Y. pestis, B. anthracis,staphylococcal enterotoxin B (SEB) and Yellow fever virus were detected. Antibody-captured coating method was established to detect F1 antibody. After determining the optimal conditions for capturing F1 antigen on fiber probes, anti-F1 antibody and 35 serum samples from infected and healthy rabbits were detected by the biosensor.In detection of antigens, optimal signals could be obtained within about 20 min by using the FOB-3. Sensitivity for detecting protein reached 50-100 ng/ml (50 ng/ml for F1 antigen and 100 ng/ml for SEB), 30-60CFU/ml for bacteria vegetative form (60 CFU/ml for Y. pestis and 30 CFU/ml for B. anthraticis), and 4×10~4 CFU/ml for B. anthraticis spore. In addition, Y. pestis could be detected specifically from Y. pseudotuberculosis, Y. enterocolitica, B. anthracis and E. coli. The result of detection of mice tissues indicated that the sensitivity by the FOB-3 reached 92.6%, specificity 100%. More over, direct absorbance and antibody-captured of antigen on the fiber were compared. The higher sensitivity in detection of anti-F1 antibodies was obtained by antibody-captured coating method with the detection limit of 10 ng/ml. Sixteen serum samples from infected rabbits were detected and the results indicated that the sensitivity by the FOB-3 reached 100%, specificity 94.7% and total validity rate (TVR) of the detection was 97.1 %, demonstrating that optic fiber biosensor is an efficient approach for detecting anti-F1 antibodies with higher sensitivity than indirect haemagglutination assay (IHA).Some pathogen and anti- Y. pestis F1 antigen antibody could be detected sensitively and specifically with the FOB-3, while it is necessary to optimize the experimental conditions and meliorate quality of polystyrene probes.