Monitoring Metabolites

By janani – Posted on 22 August 2011

Glucose, the biomarker for diabetes, is monitored through various types of glucometers. If you or a loved one has ever been diagnosed with diabetes, you probably know the hassle involved in checking glucose levels. Today’s glucometers involve a painful prick of the finger and a wait to receive readings. Some may even be guilty of not checking glucose levels four times a day, the recommended amount.
Diabetes care requires constant attention to glucose levels in the blood. In Type 1 diabetes, the cells producing insulin die, resulting in uncontrolled blood glucose that could be fatal. In Type 2 diabetes, the insulin that is produced may not be utilized effectively, and may be a consequence of obesity.

To make it easier to check glucose levels in the blood, Dr. Leah Tolosa and members of CAST are in the process of developing a continuous glucose monitoring system. This system consists of a unique sensor –a protein from E. coli bacteria, attached to a fluorescent dye so that a change in fluorescence is observed when the protein binds with glucose. This sensor reads the glucose in the interstitial fluid of the body extracted by a microdialysis device. The interstitial fluid is key because it exists between the cells of the body and contains a various number of metabolites.

However, the sensor’s function does not stop there. The sensor not only consists of a sensor for glucose, but for other metabolites as well. Glutamine, used in protein production; fatty acids, a tracker for obesity; and lactate, a biomarker of respiration, are also detected. At present, these metabolites can be tested through mass spectrometry- a complex, inconvenient, and expensive process that can only be done in a laboratory. CAST is designing a multi-sensor device that is low-cost and user-friendly for use both in hospitals and in patient’s homes. Similar to the glucose monitoring device, the metabolite sensors will be placed inside the probe and take measurements from the interstitial fluid.

The result? A probe that provides accurate measurements for a variety of different metabolites with no bleeding involved. Not only will these sensors be beneficial to the average person, these sensors also have potential to be used by neonatologists and will be useful in controlling variables of other research projects.