Flexible Piezoresistive Pressure and Temperature Sensor Module for Continuous Monitoring of Cardiac Health
Athul Krishnan, Subham Das, Mitradip Bhattacharjee
Abstract
Flexible and disposable sensors are highly coveted for their light and thin nature, robustness, pliability, and cost advantage in the manufacturing process. They are widely used for affordable health monitoring. This work presents a Poly(3,4ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) + graphene oxide (GO) temperature sensor and porous polydimethylsiloxane (PDMS) + PEDOT:PSS pressure sensor assisted health band for continuous monitoring of cardiac health. A novel single-module sensor has been developed that can detect heart rate with a high sensitivity of 2.67 kPa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-}$ </tex-math></inline-formula> (low–medium pressure range 0–5 kPa) and a temperature range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 25 °C to 45 °C with average sensitivity 0.0022 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ }\text{C}^{-}$ </tex-math></inline-formula> . Furthermore, the flexible and disposable sensors used demonstrated longevity which is considerably high for a disposable sensor set-up. The sensors have been tested in rest and active conditions, and promising results are obtained. The setup has been integrated with a smartphone application to wirelessly transmit the data obtained over a Bluetooth connection. The device has an accuracy of 95.81% for temperature and 96.03% for pressure sensing, which is comparable to conventional sensors of the same nature. The sensing patch requires considerably less power (5 nW) than the current optical-based measurement devices and is capable of detecting minute physiological signal fluctuations, making it a potential option for low-power, real-time, and home-based cardiac health monitoring.