Miniaturized 96-well ELISA chips for staphylococcal enterotoxin B detection using portable colorimetric detector.
A previously developed fluorescence sensing platform, combining spatial illumination using electroluminescence (EL) semiconductor strips with charge coupled device (CCD)-based detection (EL-CCD), was adapted to a new 96-well chip for colorimetric immunological assays, enhancing the capabilities of the EL-CCD platform. The modified system was demonstrated using a colorimetric-based enzyme linked immunosorbent assay (ELISA) for detection of staphylococcal enterotoxin B (SEB). Limits of detection (LODs) of 3.9 ng/mL (+/-2.4 ng/mL) SEB were determined with the ELISA chip measured using the EL-CCD platform, following a standard 4-h ELISA protocol. The LODs were comparable to those obtained using standard 96-well ELISA plates measured using a standard laboratory 96-well plate reader. The miniature 96-well ELISA chip however required as little as 5-microL samples, representing a tenfold reduction in sample volume compared to a standard 96-well ELISA plates. The ELISA chip also demonstrated detection of SEB spiked into various food matrices (milk, mushrooms, and mayonnaise) using limited-to-no sample preparation, with LODs ranging from 3.9 to 18.5 ng/mL depending on the matrix. The EL-CCD platform is versatile, capable of multi-mode detection (e.g., fluorescent and colorimetric along with solution and solid phase assays), and could readily be applied to other field portable or point-of-care applications.
Sapsford
Kim E
KE
Division of Biology, Office of Science and Engineering Laboratories, CDRH, FDA, Silver Spring, MD, 20993, USA.
Francis
Jesse
J
Sun
Steven
S
Kostov
Yordan
Y
Rasooly
Avraham
A
D000818:Animals; D003124:Colorimetry / Q000379:methods*; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005504:Food Analysis
D004768:Enterotoxins; C031818:enterotoxin B, staphylococcal