Stretchable Optical Sensing Patch System Integrated Heart Rate, Pulse Oxygen Saturation, and Sweat pH Detection.

Area of Science:

• Biomedical Engineering
• Wearable Technology
• Biosensors

Background:

• Continuous monitoring of physiological parameters like heart rate (HR), pulse oxygen saturation (SpO2), and sweat pH is crucial for healthcare, disease surveillance, and sports training.
• Existing monitoring systems may be invasive or lack the capability for simultaneous multi-parameter tracking.

Purpose of the Study:

• To develop a stretchable optical sensing patch system for real-time, continuous, and noninvasive monitoring of HR, SpO2, and sweat pH.
• To enable wireless data transmission of sensing data to a smartphone via Bluetooth.

Main Methods:

• A stretchable optical sensing patch system was designed using serpentine stretchable interconnects on a flexible substrate.
• A pH-sensitive silicate film was coated onto a commercial blood oxygen sensor for simultaneous sweat pH measurement.
• The system integrated optical sensors with a microcontroller for wireless data transmission.

Main Results:

• The sensor patch system demonstrated excellent repeatability and applicability in on-body assessments.
• It maintained functionality up to 35% extension, with high accuracy for HR (±1 b/min) and SpO2 (±2%).
• The system achieved a pH sensitivity of 4.42 mV/pH across a range of 4.0 to 8.0.

Conclusions:

• A single optical sensor on a flexible substrate can achieve simultaneous triple sensing (HR, SpO2, sweat pH) with excellent body contact.
• The developed sensor patch system offers a versatile platform for various applications by potentially replacing sensitive films.