Antibody Microarray for E. coli O157:H7 and Shiga Toxin in Microtiter Plates
Andrew G. Gehring,
Jeffrey D. Brewster,
Yiping He,
Peter L. Irwin,
George C. Paoli,
Tawana Simons,
Shu-I Tu,
Joseph Uknalis
Affiliations
Andrew G. Gehring
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Jeffrey D. Brewster
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Yiping He
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Peter L. Irwin
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
George C. Paoli
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Tawana Simons
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Shu-I Tu
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Joseph Uknalis
Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
Antibody microarray is a powerful analytical technique because of its inherent ability to simultaneously discriminate and measure numerous analytes, therefore making the technique conducive to both the multiplexed detection and identification of bacterial analytes (i.e., whole cells, as well as associated metabolites and/or toxins). We developed a sandwich fluorescent immunoassay combined with a high-throughput, multiwell plate microarray detection format. Inexpensive polystyrene plates were employed containing passively adsorbed, array-printed capture antibodies. During sample reaction, centrifugation was the only strategy found to significantly improve capture, and hence detection, of bacteria (pathogenic Escherichia coli O157:H7) to planar capture surfaces containing printed antibodies. Whereas several other sample incubation techniques (e.g., static vs. agitation) had minimal effect. Immobilized bacteria were labeled with a red-orange-fluorescent dye (Alexa Fluor 555) conjugated antibody to allow for quantitative detection of the captured bacteria with a laser scanner. Shiga toxin 1 (Stx1) could be simultaneously detected along with the cells, but none of the agitation techniques employed during incubation improved detection of the relatively small biomolecule. Under optimal conditions, the assay had demonstrated limits of detection of ~5.8 × 105 cells/mL and 110 ng/mL for E. coli O157:H7 and Stx1, respectively, in a ~75 min total assay time.