Development of antibody array for simultaneous detection of foodborne pathogens.
Pathogenic bacterial contaminations present serious problems for food industry and public health. Rapid, accurate and affordable assays are needed. In this study, antibody arrays to simultaneously detect two foodborne pathogenic bacteria (Escherichia coli O157:H7 and Salmonella spp.) have been developed using chemiluminescent detecting system. Solid supports using nitrocellulose membrane and poly-l-lysine (PLL) glass slide were compared and optimized for antibody array construction. Many parameters including optimal concentrations of antibodies, blocking reagents, assay time, storage time, sensitivity and cross-reactivity were considered during optimization. This study revealed that the PLL slide was a more suitable support due to highly accurate results and the absence of non-specific background. Phosphate-buffered saline (PBS, pH 7.2) and 3% skim milk in PBS buffer were optimal spotting and blocking reagents, respectively. With the same sensitivity for bacterial detection as in a conventional ELISA (10(5)-10(6)CFU/ml for the E. coli O157:H7 and 10(6)-10(7)CFU/ml for Salmonella detections), this antibody array has advantages of a much shorter assay time of 1h and much lower required amounts of antibodies. Moreover, there was no cross-reactivity in the detection among bacteria tested in this study. Bacteria detection in food sample was feasible as demonstrated using bacteria-added milk.
Karoonuthaisiri
Nitsara
N
National Center for Genetic Engineering and Biotechnology, BIOTEC, National Science and Technology Development Agency, Pathumthani, Thailand. nitsara.kar@biotec.or.th
Charlermroj
Ratthaphol
R
Uawisetwathana
Umaporn
U
Luxananil
Plearnpis
P
Kirtikara
Kanyawim
K
Gajanandana
Oraprapai
O
D015374:Biosensing Techniques / Q000295:instrumentation*; D015169:Colony Count, Microbial / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004926:Escherichia coli / Q000302:isolation & purification; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D007118:Immunoassay / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D015203:Reproducibility of Results; D012475:Salmonella / Q000302:isolation & purification; D012680:Sensitivity and Specificity