Anti-Motion Artifacts Iontronic Sensor for Long-Term Accurate Fingertip Pulse Monitoring

Abstract

Flexible pressure sensors have gained attention for their comfort, portability, and potential in long-term pulse monitoring and early cardiovascular disease diagnosis. However, stretching stress during daily activities affects sensor accuracy, causing motion artifacts (MAs) that hinder precise pulse signal detection. To address this challenge, the anti-motion artifact iontronic pressure sensor (S-smooth sensor), featuring a soft-hard stretchable interface with energy dissipation properties is developed. By regulating the local modulus of the encapsulation layer, this structure dissipates stretching stress, achieving an MAs suppression rate of up to 90%, significantly improving pulse signal accuracy and reliability. Additionally, the sensor incorporates a dielectric layer and double electrode layer (EDL) sensing interface, with a low-friction design that ensures high sensitivity (92.76 kPa−¹) and stability, maintaining performance over millions of cycles. The sensor accurately captures heart rate (HR) and pulse peak time differences (Δt) under various finger-bending conditions. When integrated into a portable wireless pulse monitoring system, it shows a heart rate loss rate of only 2.9% during intense physical activity. This approach avoids complex chemical processes and material restrictions, offering a novel solution for motion artifact suppression in sensors, with significant potential for real-time health monitoring and assisted diagnosis.