Swiss researchers have recently developed a new type of biosensor using luminescent proteins that can accurately measure the levels of human metabolites with just a drop of blood. It is expected to become the preferred tool for diagnosing and monitoring a variety of diseases due to its high accuracy and ease of use.
Metabolites are compounds produced by the body's metabolism, and diseases or injuries can cause significant changes in the levels of these metabolites in the blood. For example, elevated blood phenylalanine levels are characteristic of the genetic disorder phenylketonuria (PKU). Patients with this disease must have their blood phenylalanine levels checked regularly. Current testing methods require sending blood samples to a laboratory, and results are typically delivered to patients several days later, complicating the diagnosis and management of the disease.
To this end, researchers at the Swiss Federal Institute of Technology in Lausanne (EPFL) and the Max Planck Institute for Medical Research in Germany have developed a method to measure the concentration of metabolites in blood samples within minutes. They published their research in the latest issue of the American journal *Science*.
Researchers have developed a novel biosensor using a luminescent protein that changes color through different enzyme-catalyzed reactions. This means that the concentration of metabolites can be determined by analyzing the color of the emitted light. Using different enzyme-catalyzed reactions, the same sensor can measure the levels of various metabolites, including phenylalanine, glutamate, and glucose.
Taking the measurement of phenylalanine levels as an example, a drop of blood is first taken from the patient's finger. The blood sample is then added to a reaction buffer and used on a test strip containing a biosensor. When phenylalanine levels exceed normal limits, the light emitted by the sensor changes from blue to red; this change can be detected by an ordinary digital camera or smartphone. Finally, the phenylalanine concentration is calculated based on the color change. The entire process takes only 10 to 15 minutes.
Because the test is simple and accurate, patients can perform it themselves. Researchers are currently exploring ways to further simplify the test and automate the process.
