A Wireless Pressure Sensor Integrated with a Biodegradable Polymer Stent for Biomedical Applications

Abstract

This paper describes the fabrication and characterization of a wireless pressure sensor for smart stent applications. The micromachined pressure sensor has an area of 3.13 × 3.16 mm2 and is fabricated with a photosensitive SU-8 polymer. The wireless pressure sensor comprises a resonant circuit and can be used without the use of an internal power source. The capacitance variations caused by changes in the intravascular pressure shift the resonance frequency of the sensor. This change can be detected using an external antenna, thus enabling the measurement of the pressure changes inside a tube with a simple external circuit. The wireless pressure sensor is capable of measuring pressure from 0 mmHg to 230 mmHg, with a sensitivity of 0.043 MHz/mmHg. The biocompatibility of the pressure sensor was evaluated using cardiac cells isolated from neonatal rat ventricular myocytes. After inserting a metal stent integrated with the pressure sensor into a cardiovascular vessel of an animal, medical systems such as X-ray were employed to consistently monitor the condition of the blood vessel. No abnormality was found in the animal blood vessel for approximately one month. Furthermore, a biodegradable polymer (polycaprolactone) stent was fabricated with a 3D printer. The polymer stent exhibits better sensitivity degradation of the pressure sensor compared to the metal stent.

Fully Printed, Wireless, Stretchable Implantable Biosystem toward Batteryless, Real‐Time Monitoring of Cerebral Aneurysm Hemodynamics

“…2019, 6,1901034 frequency. However, future work will involve development of a smaller implantable coil directly integrated Adv.…”

“…Despite this requirement, the development of implantable electronics often lacks functional interrogation distances and relies on slow, low-throughput fabrication procedures. [6,7] Currently, an implantable pressure sensor is commercially available, but consists of a bulky, rigid electronics package intended for pressure sensing in larger diameter blood vessels. Many current wearable and implantable electronics still rely on rigid circuitry to enable wireless interrogation.…”

“…[12,13] Although flow diverters indicate high effectiveness, a post-treatment monitoring method is still required for assessment of cure progress and sac occlusion. [6,16] However, they still show limited readout distances, less than 3 cm in air, but wirelessly transmitted signals attuenate rapidly in tissue. To improve the postmonitoring capability, our prior works investigated a lowprofile capacitive flow sensor, which still needs wireless sensing capability for a fully implantable system.…”

Touch-mode capacitive pressure sensor with graphene-polymer heterostructure membrane

“…On the other hand, the polymer-based device, including a polyimide-metal membrane, is significantly softer (8.9 GPa), can operate in a lower pressure range (35 kPa) and is almost permanently in touch-mode, making such devices extremely sensitive [26][27][28]. The combination of a soft membrane material and a unique curved-cavity design lends the TMCPS sensor its excellent sensitivity; however the response is nonlinear over a small pressure range.…”

Eyeglasses based wireless electrolyte and metabolite sensor platform

“…1–3 Physical sensors used to monitor heart rate, 4,5 blood pressure, 6–8 body temperature, 9 body movements, 10 are already commercially available and are now commonly used in daily life. However, new non-invasive chemical sensors are critically desired to expand the scope of wearable sensor technology beyond vital signs and hence to obtain a more comprehensive information about a wearer's health and performance status.…”