A silver lining for Cannabis DUI prohibition
One of the most elusive aspects of cannabis regulation is the apprehension of those driving while under the influence of marijuana. Currrently, law enforcement officers are only trained to probe for DUI offenses by accessing the cognitive and physiological behaviors of suspects, given the lack of reliable measures to quickly check for THC-induced impairments. Although a mobile test for detecting cannabis use while driving was launched as a program in New South Wales, many questions prevent its widespread adoption.
But tech giant Philips has been working on solving this issues for nearly two decades with its THC breath analyzer. Philips is about to release the breath analyzer, which can be used by law enforcement officers on the roadsides to detect cannabis use.
The device consists of a disposable plastic cartridge for collecting and measuring saliva samples, along with a handheld analyzer. The measurement chamber of the cartridge contains magnetic nanoparticles coated with lingands that latch on to one of five different drug groups:
- Amphetamine, and
In other words, the device is essentially a drug detection machine.
How Philips brought their Breath Analyzer to life
The project was initiated in 2001, inspired by magnetic sensors developed two years earlier by researchers at the Naval Research Laboratory (NRL) to detect traces of some biowarefare agents. The centerpiece of the NRL technology was magnetoresistant (GMR) sensors (used on the hard drive of iPods to read bits), which was used to scan for certain biological molecules and toxins such as ricin and anthrax.
Philips developed their GMR as well as an optical sensor that the NRL also used to trace the bio molecules. The optical sensor deploys frustrated total internal reflection (FTIR), which is also used in fingerprint scanners and touchscreens. Philips found this preferable to the GMR, given their greater range of potential applications for everyday consumer electronics. Focusing on the optical detection method, Philips soon came up with a simpler model of the test cartridges that were easier to mass-produce.
How the Cannabis Breathalyzer works
When the sample collector absorbs sufficient saliva, it changes color and locks into place in the measurement chamber, which mixes the saliva and nanoparticles. The nanoparticles, now divided into different portions, each pretreated with one of 5 target-drug particles, are spun onto the sensor’s surface. There, the nanoparticles bind to traces of the target drug particles in the sample if there are any. If there are none, the nanoparticles stick to sensor’s drug-coated surface, indicating a drug-free sample.
Lastly, the magnetic field’s orientation which pulled the nanoparticles to the sensor is reversed to shake off any nano-labeled drug molecules which might be inadvertently glued to the sensor. This leaves behind only the properly bound particles in place to prevent false readings.
When the sample cartridge is then inserted into the handheld device in the analysis phase, the sensor is flushed with light beams. The nanoparticles left bound on the sensor change its refractive index, and the resultant change in the reflected beam’s intensity then indicates the concentrated presence of drugs in the samples.
Next, the analyzer stabilizes the different drug molecules on the various partitions on the sensor’s surface to pick out the particular drug molecules altering the refraction. It then displays the results on the electronic screen via a simple color-coded display, together with instructions for interpretations.
The results show the proportion of drug particles measured in billions per microliter of saliva. With such sensitivity, the device is even capable of detecting cardia troponin, a common indicator of a heart attack, at proportions 1,000 times below the threshold of traditional tests.
All together, the entire process, from sample collection to result reading, takes a maximum of 90 seconds.
Final words — The road ahead still riddled with questions
Philips is still putting the finishing touches on the product, and perfecting plans to introduce it to the mainstream. The company is also developing a platform for blood and saliva tests, entering into partnerships to expand its potential testing menu with more biomarkers.
This expansion is perhaps a nod to the likelihood of a stall in the mainstream adoption of the breadth analyzer for cannabis DUI purposes. There seems to be no end in sight for the debates about the accuracy of the correlation of breath THC levels and impairment levels in drivers. Currently, there are still no sufficient scientific results that determine the exact impact of various THC levels on a person’s driving skills.