Fabrication of a flexible wireless pressure sensor for intravascular blood pressure monitoring

• Published in: Microelectronic engineering 2019-05, Vol.213, p.55-61
• Main Authors: Yeh, Chao-Chi, Lo, Shao-Hsiang, Xu, Ming-Xin, Yang, Yao-Joe
• Format: Article
• Language: English
• Subjects: Biocompatibility; Blood pressure; Blood pressure monitoring; Blood vessels; Capacitor pressure sensor; Coils; Flexible sensor; L-C resonator; Linearity; Micromachining; Monitoring; Pressure sensors; Resonant frequencies; Resonators; Sensitivity; Sensors; Standard error; Substrates; Surgical implants; Wireless sensing
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2019.04.009

This work presents the development of a wireless passive pressure sensor for cardiovascular pressure monitoring. The device is designed to be inserted into a stent that can be deployed within a blood vessel using a catheter-based delivery system. By utilizing micromachining techniques, a variable capacitor and an inductor were implemented in the sensor as an L-C resonator for wireless pressure sensing and signal retrieving. The sensor employs biocompatible polymeric material, parylene-C, as the substrate material. The pressure responses of the sensor, such as the sensitivity, linearity, and hysteresis, were measured and discussed. The sensitivity was approximately 6.19 × 10−2/kPa (8.25 × 10−3/mmHg), and the linearity over the ranges of 0–6 kPa (0–50 mmHg) and 6–33 kPa (50–250 mmHg) were approximately 91.5% and 87.6%, respectively. The wireless pressure sensing performance of the sensor was evaluated using the phase-dip technique. Additionally, the measured results indicate that the resonant frequency of the resonator shifted from 211 MHz to 182 MHz, as the pressure varied from 0 to 33 kPa (250 mmHg). The maximum standard error of the mean is 0.86 MHz. Finally, the influence of coil thickness on the wireless readout performance was investigated. [Display omitted] •This work presents a flexible pressure sensor which can be inserted into a stent.•Pressure sensing signal can be wirelessly retrieved by the phase-dip technique.•The designed operational pressure range is from 0 to 33 kPa (0–250 mmHg).•Thicker metal film by using electroplating process enhances device performance.