Biodegradable blood flow sensor without battery and battery

A new device developed by researchers at Stanford University could help doctors more easily monitor the success of blood vessel surgery. The sensor, detailed in an article published on January 8 in Nature Biomedical Engineering, monitors the circulation of blood in an artery. It is biodegradable, battery-free and wireless. It is therefore compact and does not need to be removed and it can warn the patient's doctor in case of blockage.

"Measuring blood flow is crucial in many medical specialties. Therefore, a wireless biodegradable sensor could impact many areas, including vascular surgery, transplantation, reconstruction and cardiac surgery, "said Paige Fox, assistant professor of surgery and co-lead author of the study. article. "As we try to take care of patients throughout the Bay Area, in the Central Valley, California and beyond, this technology will allow us to expand our care without requiring visits or tests. face to face."

Monitoring the success of surgery on blood vessels is difficult because the first sign of trouble often comes too late. At that time, the patient often needs additional surgery with risks similar to the original procedure. This new sensor could allow doctors to remotely monitor a healing vessel, which would create earlier intervention opportunities.

Flow or not

The sensor perfectly surrounds the vessel being healed, where the pulsed blood passes to its inner surface. When the shape of this surface changes, the ability of the sensor to store an electrical charge is changed, which doctors can detect remotely from a device located near the skin but outside the body. This device requests a reading by pinging the sensor antenna, such as an ID card scanner. In the future, this device could come in the form of a sticker patch or be integrated with another technology, such as a portable device or a smartphone.

The researchers first tested the sensor in an artificial environment where they pumped air through an artery-sized tube to mimic pulsed blood flow. Surgeon Yukitoshi Kaizawa, a former postdoctoral researcher at Stanford and co-author of the paper, also implanted the sensor around an artery in a rat. Even on such a small scale, the sensor has successfully reported blood flow to the wireless reader. At this point, they were only interested in detecting complete blockages, but they found that future versions of this sensor could identify finer fluctuations in blood flow.

The sensor is a wireless version of the technology developed by chemical engineer Zhenan Bao in order to give prostheses a delicate touch.

"This one has a story," said Bao, professor K. K. Lee at the School of Engineering and co-lead author of the paper. "We've always looked at how to use this type of sensor in medical applications, but it took a while to find the right fit."

Researchers had to modify the materials of their existing sensors to make them sensitive to pulsed blood, but rigid enough to retain their shape. They also had to move the antenna to a safe place, unaffected by pulsations, and rethink the capacitor so that it could be placed around an artery.

"This very demanding project required many experiments and a new design," said Levent Beker, co-lead author of the article and postdoctoral researcher at Bao Lab. "I have always been interested in medical applications and implants, which could offer many surveillance or telemedicine options for many surgical operations."

Establish connections

The idea of ​​an artery sensor began to take shape when former postdoctoral fellow Clementine Boutry of the Bao Lab contacted Anaïs Legrand, a postdoctoral fellow at Fox Lab, and connected these groups – with James Chang's lab, the Johnson and Johnson Professor of Surgery.

Once they set their sights on the biodegradable blood flow monitor, the collaboration won the 2017 Postdocs Award at Stanford ChEM-H Interface, which supports postdoctoral research collaborations in search of new potentially transformative ideas. .

"We both value our postdoctoral researchers, but we did not foresee the real value this meeting would bring to a productive, long-term partnership," said Fox.

Researchers are now finding the best way to affix sensors to ships and refine their sensitivity. They are also eager to see what other ideas come up as their interest grows in this interdisciplinary area.

"Using sensors to allow a patient to quickly detect problems is becoming a trend in health accuracy," said Bao. "It will take engineers, medical schools and computer scientists to really work together and the issues they face are very interesting."

This article has been republished from documents provided by Stanford University. Note: Content may have changed for length and content. For more information, please contact the cited source.

Reference:

Boutry, C.M., Beker, L., Kaizawa, Y., Vassos, C., Tran, H., Hinckley, A.C.,. . . Bao, Z. (2019). Biodegradable and flexible arterial pulse sensor for wireless monitoring of blood flow. Nature Biomedical Engineering, 3(1), 47-57. doi: 10.1038 / s41551-018-0336-5