When someone has had blood vessel surgery, it's important for doctors to check that the vessel doesn't become blocked as it heals. Such blockages could someday be detected earlier and more easily than ever, thanks to an experimental new biodegradable blood flow sensor.

Developed at California's Stanford University, the implantable device takes the form of a capacitive strip that's wrapped around a blood vessel at one end, and that is attached to an antenna at the other.

As blood pulses through the vessel, it presses on the sensor's inner surface, causing its shape to change. That shape-change alters the device's capacity to store an electrical charge. Using an external device to wirelessly "ping" the antenna, doctors are able to read that capacity, and thus determine the rate at which blood is flowing. If the flow is starting to decrease, then action may need to be taken.

The sensor – which is based on technology previously developed for touch-sensitive robot skin – requires no battery, and harmlessly biodegrades after the vessel has healed. It has already been successfully tested on the artery of a live rat, that vessel obviously being much smaller and difficult to monitor than that of a human.

A smartphone or wearable device could likely serve as the external reader, although it's also possible that an electronic sticker on the skin could be used. In any case, it should be possible to wirelessly transmit readings to the internet, so doctors could check on patients' progress without requiring them to come into the office.

A paper on the research, which is being performed in the lab of chemical engineer Prof. Zhenan Bao, was recently published in the journal Nature Biomedical Engineering.