A Minute By Minute Reading Of What's In The Blood

Development to Watch

A MINUTE-BY-MINUTE READING OF WHAT'S IN THE BLOOD

Today's testing technology can measure minute quantities of thousands of chemicals. But it can't continuously monitor chemical levels in real time--a process that would be invaluable in tracking environmental contaminants or measuring chemicals, such as insulin, in the human body.

Now, chemists at Tufts University have developed a continuous chemical-sensing process. The technique takes advantage of the fact that all materials give off a faint but specific color when struck by a strong light. That can be used to analyze their chemical composition. Using a tiny glass fiber tip saturated with an antibody, a blood protein that seeks out and gloms onto specific foreign substances, the researchers can measure the concentration of chemicals in the blood with a flash of light through the fiber, then record the results electronically. And if they house the antibody in a reservoir made out of a polymer that dissolves slowly, they can measure those levels continuously. Tufts chemistry professor David R. Walt is now testing the probe as an implant in sheep to measure levels of pesticide in their blood.EDITED BY EMILY T. SMITH