Besides posing a serious environmental hazard, organophosphate-based pesticides, or OP compounds, are raw material for chemical-warfare nerve agents. Crews responding to a terrorist's nerve-agent attack have had no way to identify the compound they're dealing with until it's too late.
Yuehe Lin, a chief scientist at the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., reported Sunday at the national meeting of the American Chemical Society the successful lab test of a disposable OP sensor he fashioned from carbon nanotubes chemically fused to enzymes borrowed from the nervous system-the same enzymes that act as catalysts in neurotransmitters.
The 500-nanometer-thick tubes and their bound enzymes finely pepper a 2-by-4 millimeter sensor surface. In the presence of OP, enzyme activity is dampened. The nanotubes, acting as electrodes, sense the inhibition as a muted signal and pass that information to an off-the-shelf electrochemical detector that houses the sensor. The detector is hooked up to a notebook computer for an instant reading of even traces of OP, to as few as 5 parts per billion.