An Energy-Efficient Flexible Multi-Modal Wireless Sweat Sensing System Based on Laser Induced Graphene

Area of Science:

• Biomedical Engineering
• Wearable Technology
• Sports Science

Background:

• Real-time sweat monitoring is crucial for athletes to assess physical condition, exercise intensity, and training outcomes.
• Current wearable sports monitoring systems often use enzyme sensors with limited sensitivity.
• A multi-modal system with a wireless sensor patch, data relay, and host controller was developed.

Purpose of the Study:

• To develop a highly sensitive, mass-producible sweat sensing system for athletes.
• To improve the sensitivity of enzyme-based sweat sensors.
• To enable real-time monitoring of lactate, glucose, potassium (K+), and sodium (Na+) concentrations.

Main Methods:

• Development of a multi-modal sweat sensing system using a patch-relay-host topology.
• Integration of Near Field Communication (NFC) and Bluetooth Low Energy (BLE) for data transmission.
• Utilizing Laser-Induced Graphene (LIG) sensors decorated with Single-Walled Carbon Nanotubes (SWCNT) for enhanced sensitivity.
• Implementing a dual enzyme sensing optimization strategy.

Main Results:

• The developed LIG array sensors are manufactured rapidly (<1 minute) and cost-effectively (~0.11 yuan).
• In vitro tests demonstrated high sensitivities: 0.53 μA/mM for lactate, 3.9 μA/mM for glucose, 32.5 mV/decade for K+, and 33.2 mV/decade for Na+.
• Ex vivo sweat analysis confirmed the system's capability for characterizing personal physical fitness.

Conclusions:

• The SWCNT/LIG-based high-sensitivity lactate enzyme sensor meets the demands of wearable sports monitoring.
• The developed multi-modal system provides a viable solution for real-time athlete physiological monitoring.
• The cost-effective and rapid manufacturing process makes the sensors suitable for mass production.