Smart Bandage With Wireless Strain and Temperature Sensors and Batteryless NFC Tag

Abstract

This article presents a smart bandage with wireless strain and temperature sensors and a batteryless near-field communication (NFC) tag. Both sensors are based on conductive poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer. The highly sensitive strain sensor consists of a microfluidic channel filled with PEDOT:PSS in Polydimethylsiloxane (PDMS) substrate. The strain sensor shows 3 order (∼1250) increase in the resistance for 10% strain and considerably high gauge factor (GF) of ∼12 500. The sensor was tested for ∼30% strain, which is more than typical stretching of human skin or body parts such as chest expansion during respiration. The strain sensor was also tested for different bending and the electrical resolution was ∼150% per degree of free bending and ∼12k% per percentage of stretching. The resistive temperature sensor, fabricated on a Polyvinyl Chloride (PVC) substrate, showed a ∼60% decrease in resistance when the temperature changed from 25 • C to 85 • C and a sensitivity of ∼1% per • C. As a proof of concept, the sensors and NFC tag were integrated on wound dressing to obtain wearable systems with smart bandage form factor. The sensors can be operated and read from distance of 25 mm with a user-friendly smartphone application developed for powering the system as well as realtime acquisition of sensors data. Finally, we demonstrate the potential use of smart bandage in healthcare applications such as assessment of wound status or respiratory diseases, such as asthma and COVID-19, where monitoring via wearable strain (e.g., respiratory volume) and temperature sensors is critical.

Printed Chipless Antenna as Flexible Temperature Sensor

“…Further, their conductivity is tuneable, and this makes them attractive for sensing antenna. A few PEDOT:PSS composite based temperature sensors [47][48][49][50][51] have been reported recently, but these either do not have a suitable range of operation for biomedical or smart packaging applications or are not suitable to be used as sensing antennas due to poor electrical behavior. There is hardly any flexible and chipless printed temperature sensing antenna reported so far.…”

Millimeter Wave Power Transmission for Compact and Large-Area Wearable IoT Devices based on a Higher-Order Mode Wearable Antenna

“…Furthermore, the proposed antenna maintains a lower profile than most wearable antennas [38]. Therefore, it can be applied to a wider variety of textile substrates, making it a better candidate for on-body IoT devices, such as RF-powered smart bandages [55].…”

Energy Autonomous Sweat‐Based Wearable Systems

“…The operational life of EES can also be improved by exploiting the wireless charging via near field communication (NFC). [ 9 ] In this case, the sensors should have an integrated antenna so as to harvest energy through electromagnetic fields.…”

“…Wearable systems incorporating physical, chemical, and biological sensors and actuators have rapidly become an inseparable part of our lives for their use in a wide range of applications, such as personalized health monitoring, wellness‐tracking, early‐warning for COVID‐19, exoskeletons, prosthetics, and interactive systems for augmented/virtual reality. [ 1–9 ] The continuous operation of these systems is juxtaposed with the reliable and sustainable energy sources, currently met through: a) energy harvesters based on mechanisms such as photovoltaics, [ 10–13 ] piezoelectricity, [ 14–16 ] triboelectricity, [ 14,17–19 ] and theremoelectricity, [ 20–22 ] etc. ; b) energy storage devices such as Li‐ion batteries (LiB) [ 23–27 ] and supercapacitors (SCs), [ 28–35 ] etc.…”