As the breathalyzer does for alcohol, this experimental 'potalyzer' could provide a practical field test for determining whether a driver might be impaired from smoking marijuana.
This November, several states will vote whether to legalize marijuana use, joining more than 20 states that already allow some form of cannabis use. This has prompted a need for effective tools for police to determine on the spot whether people are driving under the influence.
Shan Wang and team have devised a potential solution, applying magnetic nanotechnology (GMR), previously used as a cancer screen, to create what could be the first practical roadside test for marijuana intoxication.
"To the best of our knowledge, this is the first demonstration that GMR biosensors are capable of detecting small molecules," Wang wrote in a paper describing the device, published in Analytical Chemistry.
Professor Shan Wang and team created a mobile device that uses magnetic biosensors to detect tiny THC molecules in saliva. Officers could collect a spit sample with a cotton swab and read the results on a smartphone or laptop in as little as three minutes.
Wang's device can detect concentrations of THC in the range of 0 to 50 nanograms per milliliter of saliva. While there's still no consensus on how much THC in a driver's system is too much, previous studies have suggested a cutoff between 2 and 25 ng/mL, well within the capability of Wang's device.
The co-authors of the Analytical Chemistry paper are Jung-Rok Lee (ME PhD'15), Joohong Choi (EE PhD'15), and Tyler O. Shultz (Biology BS'13).
This article is adapted from the Stanford Report.