Can Be Good for You

Enzymes like PTE rely upon a special kind of molecular assistance to do their jobs efficiently. Metals such as iron, zinc, and copper all perform vital roles in some of the enzymatic reactions that fuel the body s metabolism. Iron, for instance, helps the protein hemoglobin transport oxygen to organs in the body. Many metals act to stabilize the shapes of enzymes. But the body s handling of metals—some of which can be highly toxic in excessive amounts—is a tricky business. In some cases, cells exert exquisitely tight control, assuring that only one or two free metal atoms are present inside an individual cell. 

It s a far cry from the real thing, but a new artificial tongue promises to do a lot more than taste hamburgers and lick stamps. Chemist Eric Anslyn of the University of Texas at Austin and his coworkers have developed a prototype tongue biosensor for sampling liquids a tiny silicon wafer embedded with detection beads that turn color in the presence of specific chemicals. 

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