Cloth-based microfluidic devices integrated onto the patch as wearable colorimetric sensors for simultaneous sweat...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Wearable Technology

Background:

• Point-of-care (POC) devices are crucial for real-time health monitoring.
• Wearable sensors offer a non-invasive approach to analyze physiological biomarkers.
• Integrating multiple sensing capabilities into a single wearable device presents a significant advancement.

Purpose of the Study:

• To develop a flexible, wearable point-of-care (POC) device integrated into a pain relief patch.
• To enable simultaneous colorimetric sweat analysis for lactic acid, sodium ions, and pH.
• To validate the device's functionality during exercise and daily activities.

Main Methods:

• Development of cloth-based microfluidic devices (CMDs) using wax printing technology on cotton cloth.
• Immobilization of sensitive reagents in sensing zones for micro-volume sweat sample analysis.
• Quantitative and semi-quantitative colorimetric analysis using a smartphone camera and a free app (Color Grab).

Main Results:

• Excellent linear correlation between ∆RGB values and analyte concentrations for lactic acid (R² = 0.994), sodium ion (R² = 0.998), and pH (R² = 0.994).
• Achieved limits of detection (LOD) of 45.73 µg/mL for lactic acid and 56.46 µg/mL for sodium ions.
• Demonstrated high reproducibility for lactic acid (0.79%) and sodium ions (0.89%).

Conclusions:

• The developed wearable colorimetric sensors on a pain relief patch are effective for simultaneous sweat analysis.
• The device shows agreement with standard clinical laboratory methods for sweat analysis during exercise.
• This integrated patch offers a promising solution for continuous, non-invasive monitoring of key sweat analytes.