State-of-the-Art Sensors Find Traces of Zinc and Mercury



Metals in the body keep us healthy, but they can also make us sick. While small amounts of iron, copper, and zinc help proteins carry out their regular functions, metals in the wrong amount or the wrong place can cause trouble. Recent research implicates zinc in the development of Alzheimer’s and Parkinson’s diseases as well as strokes, seizures, and head injuries. Exposure to mercury, which is harmful in any amount because the body can’t get rid of it, can also cause neurological damage. Techniques that reliably locate small amounts of metals in the body are key to understanding the progression and treatment of these brain disorders as well as the roles that metals play in normal processes. Some detection methods currently exist, but most are either imprecise or difficult to implement.

Stephen Lippard, Ph.D., of the Massachusetts Institute of Technology in Cambridge may have a new way. He has developed sensors that reveal tiny amounts of zinc and mercury in cells, tissues, or water. When Lippard applied these chemical sensors to biological samples and then shone light on them, molecules of zinc or mercury in the samples lit up. Lippard tested the zinc sensors on brain tissue from rodents with head trauma or seizures and found that the sensors precisely identified zinc in damaged nerve cells. Lippard has also fashioned a sensor that selectively pinpoints even low levels of mercury in water.

The fluorescent chemosensors may offer new tools for imaging metals in the body and for studying the role of these molecules in health and disease. The technology may also prove useful for monitoring environmental quality in water, soil, and elsewhere.