Flexible Passive Wireless Pressure and Moisture Dual-Parameter Sensor for Wound Monitoring

The rate and quality of dermal wound healing can be greatly affected by mechanical pressure and moisture content, which need to be continuously monitored for wound management. Here we present a flexible passive wireless pressure and moisture sensor based on a LC-type dual resonant circuit. The sensor consists of a moisture sensitive interdigital capacitor, two identical pressure sensitive plate capacitors and two equivalent inductors. Pyramidal polydimethylsiloxane elastomer is utilized as the dielectric layer of the pressure sensitive capacitors, and graphene oxide is used as the moisture sensing material. Experimental results demonstrate that the fabricated sensor has humidity sensitivity of -61 kHz/%RH from 20 %RH to 90 %RH and pressure sensitivity of -388.6 kHz/mmHg from 0 mmHg to 100 mmHg.