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Bead-based electrochemical immunoassay for bacteriophage MS2
Jennifer H Thomas1, Sang Kyung Kim, Peter J Hesketh
1Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, USA.
Analytical Chemistry
|May 18, 2004
Summary
A new electrochemical immunoassay detects bacteriophage MS2, a simulant for biothreat viruses. This assay, using paramagnetic beads and an interdigitated array electrode, achieved a low detection limit for rapid biothreat agent identification.
Area of Science:
- Biotechnology
- Biosensors
- Analytical Chemistry
Background:
- Viruses are critical biothreat agents requiring sensitive detection methods.
- Bacteriophage MS2 serves as a surrogate for dangerous viruses like smallpox.
- Existing detection methods may lack the sensitivity or speed required for biothreat surveillance.
Purpose of the Study:
- To develop a novel electrochemical immunoassay for sensitive and rapid detection of bacteriophage MS2.
- To evaluate the performance of the immunoassay using different electrode configurations, specifically rotating disk electrode (RDE) and interdigitated array (IDA) electrodes.
- To establish a new detection limit for bacteriophage MS2 using the developed assay.
Main Methods:
- A paramagnetic bead-based sandwich immunoassay was designed using biotinylated anti-MS2 IgG and an anti-MS2 IgG-beta-galactosidase conjugate.
- The enzymatic activity of beta-galactosidase was used to convert p-aminophenyl galactopyranoside (PAPG) to electroactive p-aminophenol (PAP).
- Detection was performed using RDE amperometry and a trench interdigitated array (IDA) electrode integrated into a microfluidic channel.
Main Results:
- The RDE amperometry method achieved a detection limit of 200 ng/mL (3.2 x 10^10 particles/mL) for MS2.
- Incorporation of an IDA electrode with electrochemical recycling of the PAP/PQI couple significantly improved sensitivity.
- The IDA electrode-based immunoassay lowered the detection limit to 90 ng/mL (1.5 x 10^10 particles/mL) for MS2.
Conclusions:
- The developed paramagnetic bead-based electrochemical immunoassay offers a sensitive method for detecting bacteriophage MS2.
- The use of an IDA electrode with electrochemical recycling provides a significant advantage in lowering the limit of detection.
- This assay holds promise for rapid and accurate identification of biothreat viral agents.