Lateral flow colloidal gold-based immunoassay for pesticide

Area of Science:

• Analytical Chemistry
• Biotechnology
• Immunology

Background:

• Immunochromatographic lateral flow test strips are widely used diagnostic tools.
• Gold-based immunoassays exist in noncompetitive (sandwich) and competitive formats.
• Noncompetitive assays detect large molecules, while competitive assays are suitable for small molecules.

Purpose of the Study:

• To describe a competitive lateral flow immunoassay for detecting small molecules, specifically pesticides.
• To detail the preparation of colloidal gold and antibody-gold conjugation.
• To explain the assembly and function of a test strip for pesticide detection.

Main Methods:

• Preparation of colloidal gold and antibody-gold conjugates.
• Coating nitrocellulose membranes with goat anti-rabbit IgG (control line) and hapten-OVA conjugate (test line).
• Utilizing a competitive immunoassay format where test line intensity is inversely proportional to pesticide concentration.

Main Results:

• The competitive lateral flow immunoassay provides immediate visual results.
• The intensity of the test line color is inversely related to the pesticide concentration in the sample.
• The assay format is adaptable for multiplexed analysis of targets with distinct properties.

Conclusions:

• Competitive lateral flow immunoassay with colloidal gold is effective for detecting small molecules like pesticides.
• The described method offers a rapid, visual, and potentially multiplexed diagnostic tool.
• The assay's sensitivity is dependent on the inverse relationship between test line intensity and analyte concentration.