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Published on: February 28, 2015
Optimizing two-color semiconductor nanocrystal immunoassays in single well microtiter plate formats
Kim E Sapsford1, Samantha Spindel, Travis Jennings
1Division of Biology, Office of Science and Engineering Laboratories, US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA. kim.sapsford@fda.hhs.gov
Insights
This study developed a rapid method for simultaneously detecting chicken IgG and Staphylococcal enterotoxin B (SEB) using quantum dot (QD) tracers. The multiplex immunoassay achieved sensitive detection in a single well, comparable to single-analyte methods.
Area of Science:
- Biotechnology
- Nanotechnology
- Immunotechnology
Background:
- Simultaneous detection of multiple analytes is crucial in diagnostics.
- Quantum dots (QDs) offer unique optical properties for bio-imaging and sensing.
- Developing rapid and sensitive immunoassay platforms is an ongoing challenge.
Purpose of the Study:
- To develop a multiplex immunoassay for simultaneous detection of chicken IgG and Staphylococcal enterotoxin B (SEB).
- To utilize luminescent semiconductor quantum dot (QD) nanocrystal (NC) tracers for enhanced detection.
- To evaluate the performance of QD-based multiplex detection against traditional fluorophores.
Main Methods:
- Preparation of QD-labeled antibodies using sulfhydryl-reactive chemistry (<3 hours).
- Development of a single-well immunoassay format for simultaneous detection of chicken IgG and SEB.
- Evaluation of dose-response curves and comparison with Cy5 fluorophore.
Main Results:
- Achieved simultaneous detection of chicken IgG and SEB in a single well using QD NC tracers.
- QD-based immunoassay performance was equivalent to assays using the common fluorophore Cy5.
- Demonstrated multiplex detection with limits of detection of 9.8 ng/mL for chicken IgG and 7.8 ng/mL for SEB.
Conclusions:
- Quantum dot nanocrystal tracers enable rapid and sensitive multiplexed immunoassays.
- This method offers a viable alternative for simultaneous analyte detection in a single well.
- The developed platform shows potential for various diagnostic and research applications.
Abstract:
The simultaneous detection of two analytes, chicken IgY (IgG) and Staphylococcal enterotoxin B (SEB), in the single well of a 96-well plate is demonstrated using luminescent semiconductor quantum dot nanocrystal (NC) tracers. The NC-labeled antibodies were prepared via sulfhydryl-reactive chemistry using a facile protocol that took <3 h. Dose response curves for each target were evaluated in a single immunoassay format and compared to Cy5, a fluorophore commonly used in fluorescent immunoassays, and found to be equivalent. Immunoassays were then performed in a duplex format, demonstrating multiplex detection in a single well with limits of detection equivalent to the single assay format: 9.8 ng/mL chicken IgG and 7.8 ng/mL SEB.
