Skin-Attachable Ink-Dispenser-Printed Paper Fluidic Sensor Patch for Colorimetric Sweat Analysis

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• In situ sweat analysis offers noninvasive monitoring for lifestyle and early disease detection.
• Accurate sweat rate measurement is vital for thermoregulation and preventing heat-related illnesses.

Purpose of the Study:

• To develop a skin-attachable paper fluidic patch for simultaneous colorimetric sensing of sweat biomarkers (pH, glucose, lactate, uric acid) and sweat rate tracking.
• To demonstrate a cost-effective fabrication method for paper fluidic sensor patches using ceramic-based ink.

Main Methods:

• A skin-attachable paper fluidic patch was fabricated using an automated ink dispenser with a specialized ceramic-based ink.
• Multiplexed detection zones and a longitudinal sweat rate channel were printed, with detection zones modified with nanoparticles and the sweat rate channel incorporating a moisture-sensitive dye.
• On-body multiplexed evaluation of sweat analytes was performed, with results detectable visually or via smartphone camera.

Main Results:

• The ceramic ink created impervious, high-resolution, thermally stable, and solvent-resistant fluidic patterns.
• The modified detection zones showed improved color homogeneity and sensor sensitivity.
• The sweat rate channel effectively tracked sweat rate via moisture-induced color changes.
• Successful on-body demonstration of multiplexed sweat analyte evaluation was achieved.

Conclusions:

• The developed paper fluidic sensor patch provides a cost-effective and on-site method for analyzing multiple sweat biomarkers and sweat rate.
• This wearable technology offers significant potential for noninvasive health monitoring in health-conscious individuals.