Engineers at the University of California (UC) have created a tiny 4.5×3 mm device that can be implanted inside the body to provide real-time measurements of tissues' oxygen, and monitor the measurements wirelessly.
The device, which is powered by ultrasound waves, could help doctors monitor the health of transplanted organs or tissue and provide an early warning of potential transplant failure. The new development was announced in the journal Nature Biotechnology on April 14.
The technology also paves the way for the creation of a variety of miniaturized sensors that could track other key biochemical markers in the body, such as pH or carbon dioxide. These sensors could one day provide doctors with minimally invasive methods for monitoring the biochemistry inside functioning organs and tissues.
"It's very difficult to measure things deep inside the body. This new device can go very deep into tissue to take data from organs," said Michel Maharbiz, a UC professor of electrical engineering and computer sciences, in a report published on the university's website.
Oxygen is a key component to cells' ability to harness energy from the food that we eat, and nearly all tissues in the body require a steady supply in order to survive.
Most methods for measuring tissue oxygenation can only provide information about what is happening near the surface of the body. That is because these methods rely on electromagnetic waves, such as infrared light, which can only penetrate a few centimeters into skin or organ tissue. While there are types of magnetic resonance imaging that can provide information about deep tissue oxygenation, they require long scanning times, and so are unable to provide data in real time.
Maharbiz points out that this type of oxygen sensor differs from the pulse oximeters that are used to measure oxygen saturation in the blood.
While pulse oximeters measure the proportion of hemoglobin in the blood that is oxygenated, the new device is able to directly measure the amount of oxygen in tissue.