A cheap nanoscale detector for bacteria could be available in a few years, says Technology Review. The University of Rochester Medical Center's Benjamin Miller developed a sensor that combines a hairpin complementary DNA, a fluorescent tag, and a gold film. "The DNA stays folded over until a target genetic sequence links to it. Its unfolding results in the fluorescent molecule moving away from the gold film and glowing, which can be seen under a fluorescent microscope," the article notes.