Students' project uses bacteria to detect glucose

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Students at Missouri University of Science and Technology (S&T) recently designed a biological system that uses DNA in bacteria to detect glucose. The development may one day lead to less costly glucose test strips used by people living with diabetes.

The students embedded segments of DNA into a non-virulent strain of the bacteria E. coli that senses glucose. When glucose is present, the bacteria emit a yellow glow. The glow becomes brighter as glucose levels rise.

The project, developed for the annual Americas Regional Jamboree competition in Oct. 2011, earned the students a silver medal. The students are members of the Missouri S&T chapter's of the International Genetically Engineered Machine Foundation (iGEM).

“We designed DNA so that bacteria that have DNA would sense a change in osmolarity due to the presence of glucose,” said Erica Shannon, a senior at Missouri S&T and president of the university's iGEM chapter. In this case, osmolarity refers to the concentration of glucose in a solution.

The system developed by the Missouri S&T students could one day lead to the development of bacteria-based test strips. They would cost far less to manufacture than the chemical-based test strips used today.

Bacteria-based test strips would replace the fluorescent gene with one that causes the bacteria to change colors as glucose levels rise. A test strip could turn green to indicate normal glucose readings and red for elevated glucose readings, for example.

According to Shannon, it's also possible that an insulin gene could be added to bacteria for use in insulin pumps in which glucose readings could trigger insulin production.

Today, 366 million people in the world live with diabetes. That number is expected to rise by 10 percent, to 552 million, by 2030 if current trends continue, according to the International Diabetes Federation's 5th edition of Diabetes Atlas.

Sources: Missouri University of Science and Technology, International Diabetes Federation