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

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.

[1]  Stephen P. Boyd,et al.  Simple accurate expressions for planar spiral inductances , 1999, IEEE J. Solid State Circuits.

[2]  Wim E Hennink,et al.  In vivo biocompatibility and biodegradation of 3D-printed porous scaffolds based on a hydroxyl-functionalized poly(ε-caprolactone). , 2012, Biomaterials.

[3]  Michael C. McAlpine,et al.  3D Printed Bionic Ears , 2013, Nano letters.

[4]  Aminy E. Ostfeld,et al.  Screen printed passive components for flexible power electronics , 2015, Scientific Reports.

[5]  Salina Abdul Samad,et al.  Modulation Techniques for Biomedical Implanted Devices and Their Challenges , 2011, Sensors.

[6]  Jeong-Bong (JB) Lee,et al.  A SU-8-Based Microfabricated Implantable Inductively Coupled Passive RF Wireless Intraocular Pressure Sensor , 2012, Journal of Microelectromechanical Systems.

[7]  Christofer Toumazou,et al.  Continuous in vivo blood pressure measurements using a fully implantable wireless SAW sensor , 2013, Biomedical Microdevices.

[8]  Takao Someya,et al.  Imperceptible magnetoelectronics , 2015, Nature Communications.

[9]  Young-Soo Choi,et al.  Surface-patterned SU-8 cantilever arrays for preliminary screening of cardiac toxicity. , 2016, Biosensors & bioelectronics.

[10]  Khalil Mafinezhad,et al.  A novel analytical technique to omit the spurious passband in inductively coupled bandpass filter structures , 2016 .

[11]  Yaping Zang,et al.  Flexible suspended gate organic thin-film transistors for ultra-sensitive pressure detection , 2015, Nature Communications.

[12]  B. Shirinzadeh,et al.  A wearable and highly sensitive pressure sensor with ultrathin gold nanowires , 2014, Nature Communications.

[13]  L. Cauller,et al.  Biocompatible SU-8-Based Microprobes for Recording Neural Spike Signals From Regenerated Peripheral Nerve Fibers , 2008, IEEE Sensors Journal.

[14]  Magdy F. Iskander,et al.  An Empirical Formula for Broad-Band SAR Calculations of Prolate Spheroidal Models of Humans and Animals , 1979 .

[15]  Benjamin C. K. Tee,et al.  Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring , 2013, Nature Communications.

[16]  J. Lewis,et al.  Conformal Printing of Electrically Small Antennas on Three‐Dimensional Surfaces , 2011, Advanced materials.

[17]  H-S Philip Wong,et al.  Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care , 2014, Nature Communications.