Blood-Powered Medical Devices Have Arrived

The gold standard for diagnosing many medical conditions often involves running comprehensive tests on blood samples. For example, haematocrit tests measure the proportion of red blood cells in the blood, providing crucial information about anemia and other blood disorders. Erythrocyte sedimentation rate tests help detect inflammation in the body, which can indicate conditions such as infections, autoimmune diseases, and cancers. Measuring cardiac output through blood tests and related techniques is essential for assessing heart function and diagnosing heart failure or other cardiac conditions. Blood tests are also increasingly important in the diagnosis of Alzheimer's disease, as researchers identify biomarkers that may signal the presence of this neurodegenerative condition long before symptoms appear.

Unfortunately, many of these tests require expensive instrumentation and highly trained individuals to carry them out. All too often, these resources are not available in remote areas or in developing countries. As a result, people living in these areas are likely to go undiagnosed and untreated.

Inexpensive testing options that do not require an existing, modern healthcare infrastructure are desperately needed in these regions. A clever idea recently proposed by researchers at the University of Pittsburgh may soon help to fill this present gap. They have developed a blood-powered system that is useful in diagnosing a wide range of diseases, from diabetes and osteoporosis to Alzheimer's disease. Their system is self-powered and does not require any additional equipment for operation.

Rather than performing a large number of complex and expensive tests, the team instead chose to use a proxy — the electrical conductivity of blood. While this metric is not as specific as the information provided by other tests, it is a crucial data point. The molecules in our blood either conduct or impede the flow of electricity. For example, glucose is a conductor, so when it is present in large quantities, electrical conductivity also rises.

To make the device capable of powering itself, a triboelectric nanogenerator (TENG) was built into the device. These generators convert mechanical energy into electricity. In this case, blood introduced into the instrument actually serves as one of the conducting layers in the TENG. When a spring-loaded plunger on the top of the device is pressed down by a user, the TENG converts that motion into electricity, with the help of the blood sample that is acting as a conductor. By measuring the amount of electricity that is produced, one can determine the blood’s level of conductivity.

The correlation between voltage levels and electrical conductivity is not perfectly straightforward, however. To deal with this issue, the researchers built an AI algorithm that predicts conductivity levels. This setup worked quite well in a series of experiments. It was demonstrated that the new device compared favorably with existing methods for measuring blood conductivity.

Looking ahead, the team hopes to train their AI model with a larger, and more diverse, training dataset. This will ensure that it is well-generalized for use in a wide range of situations. They also intend to explore the possibility of using their technology to test substances other than blood.