Development of Nanoprobes as Glucose Biosensors
M. Dweik and S. Grant
University of Missouri-Columbia, US
glucose, biosensor, optical sensor, Erythrocytes, diabetes
In 2005, the American Diabetes Association (ADA) reported that 20.8 million people have diabetes, making it the fifth leading cause of death by disease in the USA. The objective is to focus on the development of glucose sensitive nanoprobes that could be inserted into erythrocytes, red blood cells (RBC). Glucose oxidase (GOx), dextran, and the fluorescent dye pairs, Texas Red (TR), and Alexa Fluor 647 (AF 647), were utilized to develop the nanoprobes.
TR, the donor fluorophores, was labeled to dextran while AF 647, the acceptor fluorophores, was labeled to GOx. The fluorescent probes are based on a competitive binding technique and uses the chemical transduction method of fluorescence resonance energy transfer (FRET) to detect the presence of glucose.
Dextran binds to GOx, but in the presence of glucose, the donor-dextran gets displaced from the acceptor-GOx, resulting in a decrease in acceptor fluorescence with a corresponding increase in donor fluorescence. Experiments were performed using fluorescence spectroscopy and the results showed that the nanoprobes displayed a sensitivity of at least 0.5 mM below 5 mM and a sensitivity of at least 3 mM above 5 mM, which meets our initial requirements for an implantable glucose sensor.
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Nanotech 2006 Conference Program Abstract