A group of students at Missouri University of Science and Technology (Missouri S&T; Rolla) have developed a biological system that uses DNA embedded in bacteria to detect glucose. Although the use of bacteria might appear to be counterintuitive at first glance, the students hope that their technology could eventually result in a new type of diabetes test strip.

The team developed the system as part of the annual Americas Regional Jamboree competition sponsored by iGEM and received a silver medal for their efforts. Their work consisted of designing genes that allow the bacteria--a nonvirulent strain of E. coli--to sense the presence of the simple sugar glucose. When glucose is present, the bacteria glow yellow, and as glucose concentrations increase, the glow becomes brighter.

The students designed DNA so that bacteria that have DNA would sense a change in osmolarity--the concentration of a compound, glucose in this case--in a solution, remarks Erica Shannon, a senior in biological sciences at Missouri S&T and president of the campus's iGEM chapter.

The team's biological system could form the basis for new, less-costly processes to help people with diabetes monitor their blood-sugar levels. It would require replacing a fluorescent gene with one that would cause the bacteria to change color based on glucose levels. This, in turn, could lead to the development of diabetes blood-test strips that could indicate glucose levels based on various colors. For example, a test strip might turn green if glucose levels are within normal ranges, yellow if the levels are borderline, and red if they are elevated.

"All you would have to do is put the DNA inside a bacteria and you've got your test strip," Shannon notes. In addition, bacteria-based test strips would be less expensive to make than current chemical-based test strips.

"In the future, based on further research, an insulin gene could be added to this system for use in insulin pumps, where specific glucose levels trigger insulin production," Shannon adds.