Smart Bandage with Inductor-Capacitor Resonant Tank Based Printed Wireless Pressure Sensor on Electrospun Poly-L-Lactide Nanofibers

Easy to use multifunctional wearable devices, with no wires hanging around, are needed for real time health monitoring at user's comfort. Herein, an inductor-capacitor (LC) resonant tank-based wireless pressure sensor, screen-printed on an electrospun Poly-L-lactide (PLLA) nanofibers-based flexible, biocompatible, and piezoelectric substrate is presented. The printed resonant tank (resonant frequency of approximate to 13.56 MHz) consists of a planar inductor connected in parallel with an interdigitated capacitor. The capacitance, of the interdigitated capacitor present on the piezoelectric substrate varies in response to applied pressure. As a result, the resonant frequency changes and the LC tank works as a wireless pressure sensor. The sensor exhibited high sensitivity 0.035 kP(-1) and 1200 Hz kPa(-1) in wireless operation with excellent durability (over 1800 cycles). The sensitivity is the highest (1.75-fold higher) among printed wireless pressure sensors reported so far. Finally, the presented LC tank-based pressure sensor is integrated on a compression bandage to demonstrate its potential use in the online monitoring of sub-bandage pressure. The application of optimum pressure by the bandage, together with the electroceutical arrangement facilitated by the piezoelectric PLLA substrate, can accelerate the cell regeneration and hence wound healing.

Automated summary

This article presents a wireless pressure sensor based on a flexible and piezoelectric substrate, which can be used for real-time health monitoring. The sensor exhibits high sensitivity, excellent durability, and potential use in online monitoring of sub-bandage pressure to facilitate wound healing.