Ultrasensitive Strain Sensor Utilizing a AgF-AgNW Hybrid Nanocomposite for Breath Monitoring and Pulmonary Function...

Area of Science:

• Biomedical Engineering
• Materials Science
• Wearable Technology

Background:

• The COVID-19 pandemic highlighted the need for advanced respiratory monitoring solutions.
• Traditional spirometers and peak flow meters pose infection risks in clinical settings.
• Wearable sensors offer a promising avenue for non-invasive, real-time pulmonary function analysis.

Purpose of the Study:

• To develop and validate a novel wearable patch-type strain sensor for comprehensive respiratory monitoring.
• To enable real-time measurement of pulmonary functions like forced volume capacity (FVC) and forced expiratory volume (FEV).
• To provide a non-invasive and infection-risk-free alternative to conventional lung function testing devices.

Main Methods:

• Fabrication of a nanocomposite strain sensor using 2D silver flakes (AgFs) and 1D silver nanowires (AgNWs).
• Characterization of the sensor's electrical conductivity, stretchability, and sensitivity.
• Optimization of sensor placement for accurate detection of breathing patterns and pulmonary function parameters.
• Comparative analysis of sensor measurements against commercial spirometers and peak flow meters.

Main Results:

• The wearable strain sensor demonstrated high conductivity (optimized 7721 S/m, max 83,836 S/m) and excellent stretchability (>1000%).
• Ultrasensitive detection of small strains was achieved, with gauge factors (GFs) of 35 and 87 at specific strain ranges.
• The sensor accurately discriminated between different breathing types and measured respiratory rate, peak flow, FVC, and FEV.
• High correlation was observed between the sensor's measurements and those from commercial pulmonary function testing devices.

Conclusions:

• The developed wearable strain sensor is a feasible and effective tool for continuous respiratory monitoring and pulmonary function analysis.
• This non-invasive technology offers a significant advantage in preventing pathogen transmission compared to traditional methods.
• The sensor's high sensitivity and reliability pave the way for widespread adoption in personal healthcare and remote patient monitoring.