Portable and label-free optical detection of sweat glucose using functionalized plasmonic nanopillar array

Area of Science:

• Nanophotonics
• Wearable technology
• Biomedical sensing

Background:

• Continuous glucose monitoring (CGM) is crucial for diabetes management.
• Current invasive electrochemical sensors pose risks like infection and skin irritation.
• Non-invasive sweat glucose sensors face challenges with sensitivity and complex sweat environments.

Purpose of the Study:

• To develop a portable, non-invasive optical sensing system for detecting glucose in sweat.
• To create a wearable platform for real-time, label-free glucose monitoring.
• To offer an alternative to traditional invasive CGM methods.

Main Methods:

• Integration of an optical watch prototype with a functionalized plasmonic silver-coated silicon nanopillar substrate.
• Utilizing 4-mercaptophenylboronic acid for selective glucose capture and optical signal transduction via Raman scattering and plasmonic detection.
• Employing compact LED illumination (623-660 nm) and wireless data transmission to a smartphone application.

Main Results:

• Demonstrated excellent sensitivity down to 22 μmol/L for glucose detection in artificial sweat.
• Achieved high selectivity in glucose detection, validated with human sweat samples.
• Confirmed applicability in real-life scenarios for continuous health monitoring.

Conclusions:

• The developed portable optical sensing system presents a promising non-invasive alternative to traditional CGM.
• Integration of nanophotonic sensors with wearable platforms enables continuous health monitoring and personalized medicine.
• The system shows potential for improving diabetes care through accessible and user-friendly technology.