A Fully Integrated Wearable Microfluidic Electrochemical Sensor with Ultrasonic Connecting and Hot-Pressing Bonded...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Wearable Technology

Background:

• Continuous monitoring of human biomarkers is crucial for health management.
• Existing wearable sensors face challenges like sample leakage and limited biomarker detection.
• Noninvasive monitoring of glucose and electrolytes in sweat is highly desirable.

Purpose of the Study:

• To develop a fully integrated wearable microfluidic electrochemical sensor (FIWMES) for simultaneous, noninvasive monitoring of glucose, Na+, K+, and Ca2+ in human sweat.
• To address challenges in structural integration, sample leakage, and multiple-biomarker detection in wearable sensors.
• To provide a stable and reliable platform for tracking dynamic metabolic changes.

Main Methods:

• A hybrid bonding process combining ultrasonic connecting and hot-pressing was used for structural integration of the FIWMES.
• The sensor integrates a dendritic sweat-collecting module, microfluidic chamber, and 3D-arranged sensing units.
• Electrochemical sensing was employed for glucose, Na+, K+, and Ca2+ detection.

Main Results:

• The hybrid bonding process ensured high interfacial bonding strength (>65 N), excellent sealing (no leakage after 200 bends), and precise temperature control (<51 °C).
• The FIWMES demonstrated efficient sweat capture, sample manipulation, and simultaneous biomarker detection.
• The glucose sensor showed a sensitivity of 6.4 μA/mM with anti-interference capabilities. Na+, K+, and Ca2+ sensors exhibited near-Nernstian responses (65.3, 64.3, and 38.2 mV/decade, respectively).

Conclusions:

• On-body trials confirmed the practical wearability and accuracy of the FIWMES in tracking metabolic changes like postprandial glucose increases and electrolyte variations.
• The developed FIWMES offers a stable and robust technical platform for effective chronic disease management through continuous sweat biomarker monitoring.
• This research advances wearable sensor technology for noninvasive health diagnostics.