Dual-mode ion-selective electrodes and distance-based microfluidic device for detection of multiple urinary...

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Accurate monitoring of urine electrolytes is crucial for diagnosing and managing various health conditions.
• Existing methods for electrolyte analysis can be complex, expensive, and time-consuming.
• There is a need for rapid, portable, and cost-effective diagnostic tools for point-of-care testing.

Purpose of the Study:

• To develop a novel microfluidic paper device (ISE-dPAD) for simultaneous potentiometric and colorimetric detection of urine electrolytes.
• To optimize the fabrication and performance of ion-selective electrodes (ISEs) integrated onto the paper device.
• To validate the device's performance in analyzing human urine samples.

Main Methods:

• Fabrication of a microfluidic paper device integrating ion-selective electrodes (ISEs) and a distance-based paper device (dPAD).
• Coating electrode zones with polystyrene and modifying surfaces with carbon black to enhance hydrophobic properties and electrochemical characteristics.
• Optimization of polymer coating layer for improved ISE sensitivity.
• Potentiometric and colorimetric analysis of potassium (K+), sodium (Na+), and chloride (Cl-) in urine samples.

Main Results:

• The developed ISEs exhibited high sensitivity for K+ (54.14 mV/decade) and Na+ (55.08 mV/decade) within specified concentration ranges.
• Achieved low limits of detection (LOD) for K+ (0.05 mM) and Na+ (1.36 mM), and for Cl- (0.16 mM).
• Validation in human urine showed high recovery rates (90-108%) for all measured electrolytes, confirming successful application in a complex matrix.

Conclusions:

• The dual-mode ISE-dPAD offers a cost-effective ($0.33/test), eco-friendly, and portable solution for simultaneous urine electrolyte analysis.
• The device requires a small sample volume (100 μL) and is simple to operate, making it suitable for point-of-care applications.
• This technology represents a significant advancement in accessible and efficient diagnostic tools for electrolyte monitoring.