Kirigami-Shaped Dual-Functional Strain and Temperature Sensors for Monitoring Body Movements and Hyperthermia Toward Physiotherapy Applications

Abstract

Multifunctional sensors find widespread applications in wearable healthcare, Internet-of-Things, environmental monitoring, and human-machine interactions, yet they suffer from reduced stretchability, durability, wearability, and enhanced signal crosstalk. This work presents a new kirigami-shaped dual-functional patch that integrates both strain and temperature sensors in a single platform. The kirigami architecture allows out-of-plane deformation of the sensors enabling them to conform to different body parts. The sensing regions are functionalized with gold nanoparticle-decorated multi-walled carbon nanotubes that provide highly sensitive and repeatable performance. The strain sensor has a gauge factor of around 220 at 0.12% bending strain and the temperature sensor shows a sensitivity of 0.0278 kΩ °C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . Additionally, the sensor demonstrates an ultra-high stretchability for an applied tensile strain of up to 180%. The sensors can precisely monitor the dynamic bending of different joints in the body and temperature as well as decouple the strain and temperature measurements in response to dual stimuli. Furthermore, the sensors are interfaced with an Internet-of-Things platform that allows wireless transmission of body motion and temperature measurements to the cloud. The versatile nature of the sensing patch holds great promise for continuous monitoring of the progress in physiotherapy so that recovery can be tracked in real-time and appropriate intervention measures can be applied.