Diagram of Biodegradable Pressure Sensor.
Artist’s depiction of the biodegradable pressure sensor wrapped around a blood vessel with the antenna off to the side (layers separated to show details of the antenna’s structure). (Image credit: Levent Beker)

A new device developed by Stanford University researchers could make it easier for doctors to monitor the success of blood vessel surgery. The sensor monitors the flow of blood through an artery. It is biodegradable, battery-free, and wireless, so it is compact, doesn’t need to be removed, and it can warn a patient’s doctor if there is a blockage.

Monitoring the success of surgery on blood vessels is challenging, as the first sign of trouble often comes too late. By that time, the patient often needs additional surgery that carries risks similar to the original procedure. This new sensor could let doctors keep tabs on a healing vessel from afar, creating opportunities for earlier interventions.

The sensor wraps snugly around the healing vessel, where blood pulsing past pushes on its inner surface. As the shape of that surface changes, it alters the sensor’s capacity to store electric charge, which doctors can detect remotely from a device located near the skin but outside the body. That device solicits a reading by pinging the antenna of the sensor, similar to an RFID card scanner. In the future, this device could come in the form of a stick-on patch or be integrated into other technology, like a wearable device or smartphone.

The sensor was first tested in an artificial setting where air was pumped through an artery-sized tube to mimic pulsing blood flow. A surgeon also implanted the sensor around an artery in a rat. Even at such a small scale, the sensor successfully reported blood flow to the wireless reader. At that point, the researchers were only interested in detecting complete blockages, but they did see indications that future versions of this sensor could identify finer fluctuations of blood flow.

The researchers are now seeking the best way to affix the sensors to the vessels and refine their sensitivity. They are also looking forward to what other ideas will come as interest grows in this engineering and medicine interdisciplinary area.

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