Such stretchable wireless sensors could be used to monitor changes in aneurysms, bulges that can cause death or serious injury if they rupture. The stretchable sensor, operates without batteries, and would be wrapped around stents or diverters implanted to control blood flow.
The sensor can be made using aerosol jet 3D printing to create conductive silver traces on elastomeric substrates. A sensor placed in a blood vessel could allow more frequent evaluations without the use of imaging dyes which can be harmful to the patient.
The six-layer sensor is fabricated from biocompatible polyimide, two separate layers of a mesh pattern produced from silver nanoparticles, a dielectric and soft polymer-encapsulating material. The sensor would be wrapped around the stent or flow diverter, which must be less than two or three millimeters in diameter to fit into the blood vessels. The sensor includes a coil to pick up electromagnetic energy transmitted from another coil located outside the body.
"We could use it to measure an incoming blood flow to the aneurysm sac to determine how well the aneurysm is healing, and to alert doctors if blood flow changes," said Woon-Hong Yeo, assistant professor of mechanical and biomedical engineering at Georgia Tech. "We will be able to accurately measure blood flow to detect changes as small as 0.05 meters per second."
Because the sensor can be fabricated in a single step without costly cleanroom facilities, it could be manufactured in higher volume at lower cost.
Related links and articles:
"Fully Printed, Wireless, Stretchable Implantable Biosystem toward Batteryless, Real-Time Monitoring of Cerebral Aneurysm Hemodynamics" ( Advanced Science , 2019) https://doi.org/10.1002/advs.201901034