Portable drug and bioterror sensor developed with help of high school student

Published 28 February 2006

We should not give up on the quality of U.S. high school education. In evidence: A portable cocaine sensor made with inexpensive, off-the-shelf electronics may well be the wave of the future in detecting drug trafficking and bioterror agents. Researchers at the University of California, Santa Barbara, two high school students, and a Nobel laureate collaborated to come up with a valuable bioterrorism and medical detection instrument. The first use of the new portable system is in cocaine detection. “Cocaine serves as an ideal and representative target for testing new analytical techniques due to pressing needs for its rapid detection in law enforcement and clinical settings,” wrote the authors of the study in the 18 February issue of the Journal of the American Chemical Society. Currently U.S. law enforcement detects drugs by using dogs, lab tests, and the Scott test which adds a chemical to white powder to change its color. Kevin Plaxco, associate professor of chemistry and biochemistry and a co-author of the Journal study, says that cocaine manufacturers could mask the smell of cocaine with powered sugar, flour, coffee, or add a chemical to block color change. Moreover, lab tests are expensive and timely. “It’s difficult to beat the evolution of dogs trained to sniff sensitive materials,” he said.

Researchers believe their sensor could be more accurate and efficient. They note the sensor can detect cocaine in blood or saliva to a degree of a few micromolars, equivalent to that of a drop of kilogram of cocaine in an Olympic-sized pool or three parts per million in blood. More testing needs to be done to increase the sensitivity of testing cocaine in the blood at a much smaller degree, if .3 parts per million of cocaine in the blood could be considered “stoned on cocaine,” researchers concluded. To make the sensor, researchers took a DNA molecule that converts from a floppy and unfolded shape into a structured, folded shape in the presence of cocaine, thereby observing the changes in DNA and how electrons travel through it. The sensor is then made portable once placed in electronics the size of a small handheld device.

We have developed a method of detecting small molecules and proteins in a way that is not specific to cocaine — a whole class of biosensors can be based on this concept,” 2000 chemistry Nobel laureate Alan Heeger said. “It can be applied to the prevention of bioterrorism. It is beautiful work; the sensor is fully portable.” Researchers also note that the sensor could be used for medical purposes in detecting and regulating prescription drug use such as cyclosporine or a family of antibiotics known as aminoglycosides.

The sensors were easy to make that even the two California high school seniors Elaine Doctor and McCall Wood, who were interning over the summer for six weeks helping with the project, made and tested their own sensors. The University is already in talks with companies interested in licensing the technology.

-read more in this news release; read the Journal article (sub. req.)