Special paper can sniff poison in drinking water

WASHINGTON - A strip of paper infused with carbon nanotubes can be a quick, cheap, portable and sensitive bio-sensor that can allow water treatment plants and individuals to verify the safety of drinking water on a more regular basis by detecting a toxin produced by algae.

This bio-sensor performs 28 times faster than the complicated method most used today to detect microcystin-LR, (MC-LR) a chemical compound produced by cyanobacteria, or blue-green algae, found commonly in nutrient-rich waters.

MC-LR, even in very small quantities, is suspected to cause liver damage and possibly liver cancer. The substance and others like it are among the leading causes of biological water pollution.

It is believed to be a culprit of mass poisonings going back to early human history, said Nicholas Kotov, professor in chemical, biomedical engineering and materials science at the University of Michigan (U-M), who led the project.

Water treatment plants - even in developed countries - can’t always remove MC-LR completely, nor can they test for it often enough, Kotov said.

“The safety of drinking water is a vital issue in many developing countries and in many parts of the United States,” Kotov said. “We’ve developed a simple and inexpensive technology to detect multiple toxins.”

The technology could easily be adapted to detect a variety of harmful chemicals or toxins in water or food, said an U-M release.

The bio-sensor device is about the size of a home pregnancy test, Kotov said. Results appear in fewer than 12 minutes. To adapt it for other toxins, Kotov said, scientists could simply replace the antibodies that bond to the toxin.

These findings are slated for publication in Nano Letters.