Quantitative Detection of Digoxin in Plasma Using Small-Molecule Immunoassay in a Recyclable Gravity-Driven...

Area of Science:

• Biomedical diagnostics
• Analytical chemistry
• Microfluidics

Background:

• Immunoassays are vital for diagnostics and research.
• Challenges exist in precise quantification and small-molecule detection.
• Existing methods lack stability and reproducibility.

Purpose of the Study:

• To develop a stable and reproducible small-molecule immunoassay.
• To enable precise quantification of digoxin in plasma.
• To integrate the assay into a microfluidic chip for point-of-care applications.

Main Methods:

• A two signal-mode immunoassay with an internal reference was designed.
• The system was used for quantitative monitoring of digoxin.
• The assay was integrated into a gravity-driven microfluidic chip (G-Chip).

Main Results:

• The immunoassay demonstrated high stability and reproducibility.
• Digoxin concentration was accurately monitored in the clinically relevant range (0.6-2.6 nm).
• The G-Chip required only 10 µL of plasma and allowed fast detection.

Conclusions:

• The developed immunoassay overcomes limitations in conventional methods.
• The G-Chip offers a stable, reproducible, and efficient platform for digoxin detection.
• This technology holds potential for developing point-of-care diagnostic devices.