LC Wireless Sensitive Pressure Sensors With Microstructured PDMS Dielectric Layers for Wound Monitoring

Mechanical pressures affect the rate and quality of dermal wound healing. It is therefore important to continuously monitor the mechanical pressure on a wound site so as to evaluate neovascularization and cellular proliferation under pressure. Based on an LC (inductor-capacitor) passive wireless principle, this paper presents the design, fabrication, and measurement of LC sensors embedded in a commercial bandage. Pyramidal polydimethylsiloxane elastomers used as the dielectric of the capacitive pressure sensor were fabricated by using a silicon anisotropic etching mold. Simulation and analysis of the LC sensor and wound environment effects were performed. The sensor embedded in the bandage stuck on the skin was measured, showing that its resonant frequency changes according to a linear function of applied pressure in a range of 0-200 mmHg with a sensitivity of -270.8 kHz/mmHg. The demonstrated LC sensor is completely flexible and wearable, which is proper for the future smart bandage.