Wearable Osmotic-Capillary Patch for Prolonged Sweat Harvesting and Sensing

Area of Science:

• Biomedical Engineering
• Wearable Technology
• Biomarker Detection

Background:

• Sweat biomarkers offer valuable health insights but are underutilized due to limitations in current collection devices, especially at low sweat rates.
• Existing sweat harvesting technologies struggle with passive collection during resting states, limiting continuous health monitoring.

Purpose of the Study:

• To develop and evaluate a novel hydrogel-based wearable patch for efficient sweat harvesting and biomarker analysis without active perspiration.
• To demonstrate the capability of the platform for continuous, long-term sweat sampling and lactate detection in both in vitro and in vivo settings.

Main Methods:

• Utilized an osmosis-driven hydrogel interfaced with skin for sweat collection, bypassing the need for active sweating.
• Integrated paper-based microfluidics for sweat transport via capillary action to a testing zone and evaporation pad.
• Investigated the impact of hydrogel solute content and evaporation pad area on sweat extraction efficiency and duration.

Main Results:

• The hydrogel platform demonstrated continuous sweat biomarker sampling from a model skin system for up to 12 hours.
• On-skin testing confirmed the device's ability to collect sweat lactate from resting and exercising human subjects.
• Observed a direct correlation between exercise, muscle activity, and increased sweat lactate levels.

Conclusions:

• The developed hydrogel patch offers a new principle for passive sweat fluid harvesting and management in wearable devices.
• This technology advances the potential for next-generation wearable systems for non-invasive health monitoring through sweat analysis.
• The platform's ability to collect biomarkers at rest and during activity broadens the scope of sweat-based diagnostics.