Thin-Film Flexible Wireless Pressure Sensor for Continuous Pressure Monitoring in Medical Applications

Abstract

Physiological pressure measurement is one of the most common applications of sensors in healthcare. Particularly, continuous pressure monitoring provides key information for early diagnosis, patient-specific treatment, and preventive healthcare. This paper presents a thin-film flexible wireless pressure sensor for continuous pressure measurement in a wide range of medical applications but mainly focused on interface pressure monitoring during compression therapy to treat venous insufficiency. The sensor is based on a pressure-dependent capacitor (C) and printed inductive coil (L) that form an inductor-capacitor (LC) resonant circuit. A matched reader coil provides an excellent coupling at the fundamental resonance frequency of the sensor. Considering varying requirements of venous ulceration, two versions of the sensor, with different sizes, were finalized after design parameter optimization and fabricated using a cost-effective and simple etching method. A test setup consisting of a glass pressure chamber and a vacuum pump was developed to test and characterize the response of the sensors. Both sensors were tested for a narrow range (0–100 mmHg) and a wide range (0–300 mmHg) to cover most of the physiological pressure measurement applications. Both sensors showed good linearity with high sensitivity in the lower pressure range <100 mmHg, providing a wireless monitoring platform for compression therapy in venous ulceration.

Flexible Wireless Passive LC Pressure Sensor with Design Methodology and Cost-Effective Preparation

“…Based on Ecoflex, the sensitivity of the sensor obtained through the experiment is higher than that achieved by simulation, mainly due to the difference between the material parameters in the simulation and the actual situation. The flexible LC pressure sensor designed based on Ecoflex material in this paper not only has higher pressure sensitivity than most sensors reported in the existing works (as shown in Table 2) but also fits human skin well and has higher wearing comfort compared to the sensors based on PI substrate and PDMS substrate [20,29].…”

“…The flexible LC pressure sensor designed based on Ecoflex material in this paper not only has higher pressure sensitivity than most sensors reported in the existing works (as shown in Table 2 ) but also fits human skin well and has higher wearing comfort compared to the sensors based on PI substrate and PDMS substrate [ 20 , 29 ].…”

Fabrication of Suspended PMMA-Graphene Membrane for High Sensitivity LC-MEMS Pressure Sensor

“…Previous research revealed that the 10-100 MHz operating frequencies are safe for in vivo wireless measurements [27]. The sensitivity of the LC-MEMS pressure sensor from previous studies was in the range between 2 to 162 kHz/mmHg [16][17][18][19][20][21][22]25,28]. However, sensitivity values at higher rates are required for more accurate and precise measurements.…”

Wearable and Nearable Biosensors and Systems for Healthcare

“…The aim of this Special Issue of Sensors is to provide an open collection of state-of-the-art investigations on wearable and nearable biosensors and systems in order to foster further technological advances and the use of the technology to benefit healthcare. The 12 papers that constitute this Special Issue offer both depth and breadth pertaining to wearable and nearable technology [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Depth is afforded through a critical mass of studies on accelerometers [ 3 , 4 , 5 , 7 , 9 , 10 ], signal processing [ 1 , 2 , 4 , 5 , 7 , 10 , 11 ], and cardiovascular monitoring applications [ 2 , 5 , 6 , 7 , 9 , 10 , 12 ], whereas breadth is given through new biosensors [ 12 ] and data transmission [ 9 ], other clinical applications including surgical training [ 8 ] and brain-computer interfaces [ 1 ], and validation of commercial devices [ 6 ], which is crucial for adoption.…”

“…Farooq et al [ 12 ] developed a thin-filmed flexible wireless pressure sensor for interface pressure monitoring during leg compression treatment of venous insufficiency. The sensor is based on a pressure-dependent capacitance and inductive coil to allow passive and wireless measurement.…”