Selective Ion Sensing in Artificial Sweat Using Low-Cost Reduced Graphene Oxide Liquid-Gated Plastic Transistors.

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Health monitoring is shifting towards point-of-care and wearable devices.
• Two-dimensional materials (2DMs) show promise for electronics but face challenges in wearable applications.
• Reduced graphene oxide (rGO) is a key 2DM with potential for advanced sensor development.

Purpose of the Study:

• To develop novel 2DM-based wearable sensors for cation detection in artificial sweat.
• To utilize reduced graphene oxide (rGO) liquid-gated transistors (LGTs) for enhanced sensing capabilities.
• To demonstrate scalable manufacturing potential for 2DM wearable technologies.

Main Methods:

• Fabrication of flexible rGO-based LGTs using laser micromachining.
• Functionalization of transistor channels with ion-selective membranes (ISMs) for analyte selectivity.
• Real-time monitoring of potassium (K+) and sodium (Na+) ions in artificial sweat using pulsed gate voltage.

Main Results:

• Demonstrated high selectivity and sensitivity for target cations (K+ and Na+) in artificial sweat.
• Achieved fast sensor response times (5-15 seconds) and linear responses over a wide concentration range (10 µm to 100 mm).
• Utilized low working voltages (<0.5 V) and exhibited high sensitivity (1 µA/decade).

Conclusions:

• The developed rGO-based LGTs represent a significant advancement for wearable cation sensing.
• The fabrication strategy shows potential for scalable manufacturing of 2DM-based health monitoring devices.
• This work paves the way for next-generation wearable sensors utilizing 2D materials for continuous health monitoring.