Quantitative immunochromatographic analysis: theory and application to theophylline immunoassay

Area of Science:

• Biochemistry
• Analytical Chemistry
• Immunology

Background:

• Rapid and accurate analysis of biological fluids is crucial for clinical diagnostics.
• Existing immunochromatographic techniques may have limitations in precision and speed.

Purpose of the Study:

• To develop a novel immunochromatographic technique for rapid analysis of biological fluids.
• To create a sensitive and precise assay for theophylline quantification.

Main Methods:

• Construction of quasi-one-dimensional antibody lattices using Sepharose beads conjugated with anti-theophylline antibodies in capillary tubes.
• Development of a competitive enzyme immunoassay utilizing the antibody lattices.
• Design of capillary columns to subtract a preset threshold quantity of antigen.

Main Results:

• The developed microcolumn system achieved high bound/free antigen ratios, enabling precise antigen subtraction.
• The competitive enzyme immunoassay for theophylline demonstrated a dose-response consistent with theoretical predictions.
• The assay procedure was completed in under 30 minutes with a sensitivity limit of approximately 20 ng/ml.

Conclusions:

• The novel immunochromatographic technique is suitable for rapid analysis of biological fluids.
• The assay shows potential for routine clinical serum sample analysis.
• The theoretical analysis supports the observed high bound/free antigen ratios in the quasi-one-dimensional system.