Bead-assisted displacement immunoassay for staphylococcal enterotoxin B on a microchip.
A microchip-based, displacement immunoassay for the sensitive laser-induced fluorescence detection of staphylococcal enterotoxin B is presented. The glass microchip device consists of a microchannel that contains a double weir structure for supporting antibody-functionalized microbeads. After a 30-min sample preparation step, the displacement assay was performed without user intervention and produced quantitative results in an additional 20 min. Linear detection responses were observed over 6 orders of magnitude and provided detection limits down to 1 fM (28.5 fg/mL). The surprisingly low detection limits are hypothesized to arise from field-based enrichment analogous to field-amplified stacking, chromatographic effects, and limited diffusion lengths in the microbead bed. The assay was challenged with bovine serum albumin, casein, and milk sample matrixes. This system has the potential to provide highly sensitive detection capabilities for target biomolecules.
Haes
Amanda J
AJ
Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue, SW, Code 6112, Washington, DC 20375-5342, USA.
Terray
Alex
A
Collins
Greg E
GE
D000818:Animals; D002364:Caseins / Q000032:analysis*; D002417:Cattle; D004768:Enterotoxins / Q000032:analysis* / Q000633:toxicity; D007118:Immunoassay; D007834:Lasers; D046208:Microchip Analytical Procedures; D008892:Milk / Q000737:chemistry* / Q000633:toxicity; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D002364:Caseins; D004768:Enterotoxins; D012710:Serum Albumin, Bovine; C031818:enterotoxin B, staphylococcal