USA - Device Offers a Roadside Dope Test

[chillinwill]

The system uses magnetic nanoparticles to detect traces of cocaine, heroin, cannabis, and methamphetamine

Later this year, Philips will introduce a handheld electronic device that uses magnetic nanoparticles to screen for five major recreational drugs.

The device is intended for roadside use by law enforcement agencies and includes a disposable plastic cartridge and a handheld analyzer. The cartridge has two components: a sample collector for gathering saliva and a measurement chamber containing magnetic nanoparticles. The particles are coated with ligands that bind to one of five different drug groups: cocaine, heroin, cannabis, amphetamine, and methamphetamine.

Philips began investigating the possibility of building a magnetic biodetector in 2001, two years after a team of researchers at the Naval Research Laboratory (NRL) in Washington, DC, first used magnetic sensors similar to those employed in hard drives to sniff out certain biowarfare agents. The NRL scientists labeled biological molecules designed to bind to target agents with magnetic microbeads, and then scanned for the tagged targets optically and magnetically. The latter approach used the same giant magnetoresistant (GMR) sensors that read the bits on an iPod's hard drive. They quickly developed a shoebox-sized prototype capable of detecting toxins, including ricin and anthrax.

Philips initially developed both a GMR sensor and an optical one that relies on frustrated total internal reflection (FTIR)--the same phenomenon that underlies fingerprint scanners and multitouch screens. The company decided to go the FTIR route in order to exploit its expertise in building optical sensors for consumer electronics devices, says Jeroen Nieuwenhuis, technical director of Philips Handheld Immunoassays, the division responsible for commercializing the biosensor technology, which goes by the trade name Magnotech.

Moving to an optical detection method also allowed Philips to simplify the test cartridges that the device employs, making them easier to mass-produce, says Nieuwenhuis. With the current FTIR-based system, "we can make simpler cartridges in larger quantities more easily," he adds.

Once the device's sample collector has absorbed enough saliva, it automatically changes color and can then be snapped into the measurement chamber, where the saliva and nanoparticles mix. An electromagnet speeds the nanoparticles to the sensor surface, different portions of which have been pretreated with one of the five target-drug molecules. If traces of any of the five drugs are present in the sample, the nanoparticles will bind to them. If the sample is drug free, the nanoparticles will bind to the drug-coated sensor surface instead.

The orientation of the magnetic field that first drew the nanoparticles to the sensor is then reversed, pulling away any nano-labeled drug molecules that may accidentally have stuck to the sensor surface but leaving legitimately bound ones in place. This last magnetic trick promises to reduce what Larry Kricka, a clinical chemist at the University of Pennsylvania who recently co-authored an article in Clinical Chemistry on the use of magnetism in point-of-care testing, calls "a major restraint in such assays": the unintentional capture of molecular labels on the test surface, a leading cause of both false positives and false negatives. Kricka is not involved with Philips but does serve as a consultant to T2 Biosciences, a Cambridge, MA, firm that promotes a magnetic biosensor based on MRI technology.

During the analysis phase, a beam of light is bounced off the sensor. Any nanoparticles bound to the surface will change its refractive index, thereby altering the intensity of the reflected light and indicating the concentration of drugs in the sample. By immobilizing different drug molecules on different portions on the sensor surface, the analyzer is able to identify the drug traces in question. An electronic screen displays instructions and a simple color-coded readout of the results.

The test takes less than 90 seconds and can detect drugs at concentrations measured in parts-per-billion using a single microliter of saliva. The sensor is capable of even greater sensitivity--it has been used to detect cardiac troponin, a commonly used indicator of heart attack, at concentrations 1,000 times lower.

Philips plans ultimately to enter the healthcare market. It is working on a platform capable of testing blood as well as saliva and is seeking partners that can help expand its testing menu by providing it with additional biomarkers.

Other researchers have built experimental devices to magnetically detect a wide range of biomolecules in minuscule samples of blood or saliva at extremely low concentrations. Often this involves using microfluidic or magnetic forces to quickly shepherd the magnetically labeled molecules through scanners--though a group at the University of Utah has even built a prototype in which a sample-laden stick is swiped across a GMR sensor, like a credit-card through a reader.

The combination of high sensitivity, low sample volumes, miniaturization, speed, and ease of use has raised hopes for a handheld biosensor that could perform sophisticated tests with high accuracy.

"Everyone's trying to get there," says Kricka. "The question is who's going to win?" With Philips set to introduce its drug tester in Europe by the end of the year in partnership with the British diagnostics firm Cozart, the consumer electronics maker appears poised to take the prize.

By Alexander Gelfand
August 4, 2009
Technology Review
http://www.technologyreview.com/biomedicine/23111/

Reputation Comments on this post:

wow. great article, thanks for finding & posting it!

[Chronix]

God damnit!!

[Desertfox]

...And now any freedom we still had is gone!

[bman1]

what if you have horrible cotton mouth and no saliva

[Junkhead23]

How does it differentiate on how long ago a drug has been taken though?

[runitsthepolice]

Saliva tests only detect very recent use. So pretty much swiy would have to have used in the last 12-24 hours for it to be detectable (depends on the drug). Extremely sensitive saliva testing is not new. Currently it is standard practice to test saliva samples in probation and drug court programs with no cutoff - if you have 1 nanogram present you fail. Luckily substances do not stay in the saliva for very long.

This device would be useful for arresting drugged drivers.

[Junkhead23]

Pacman gets saliva tested at clinic and that registers heroin after 4 days

[chillinwill]

Originally Posted by Junkhead23

Pacman gets saliva tested at clinic and that registers heroin after 4 days

RR has taken a saliva test and tested positive 2 days after heroin use and negative 3 days after use. This has happened several times to him...It seems that at least for heroin, that he would always test negative after 48 hours from last use. I guess it can just vary depending on body chemistry. Although it does seem unfair if you tested positive 4 days from last use when you were driving and got charged with drugged driving.

[Greenport]

Sooo....use mouthwash before driving?

[The Happiest Little Nug]

^Then you'd show up drunk. Mouthwash is mostly alcohol. I bet some sort of diluted acid could really fuck with one of those things.

[ScorpioSunshine]

Couldn't this actually work *toward* the road to legality? One of the pitfalls of legality was that officers would have no way to determine if a driver was under the influence of ...let's say heroin... because no standard, roadside testing measures were available, so the thought was perhaps people would do dope and drive recklessly because they couldn't get caught. (I know that's not the reason...just "a" reason)

Now, there *is* a way to measure, or it's at least heading in that direction. I think a lot of pro-legal groups will actually push for this. With a field test available, something like this *could* put other drugs on a level playing field with alcohol *if* it were to measure intoxication and not just if one had the drug present in their system.

Of course there is a long way to go... Misinformation ... old ways of thinking, "moral" reasons...

But in the end something like this could actually be beneficial. Could... not necessarily will. Unfortunately, I don't think it will be just yet. We'll see!

ScorpioSunshine added 1 Minutes and 57 Seconds later...

^^ Let me add that I don't like the idea of this device as-is, and I think it's going to need some tweaking and will probably create more trouble for users at first. But the idea of it *could* be beneficial for legality if we think in broad terms.

I hope that makes sense, lol.

[motorhead]

Impaired driving is a bad thing. Doesn't matter what one is impaired on. When fucked up people get behind the wheel then there is a better than average chance that bad shit can happen.

However it seems this device can be used for purposes other than pinching impaired drivers, like giving cops the right to search or bust people for possession or whatever.

I guess in this case there is a fine line between protecting the greater good and an individuals rights?

[runitsthepolice]

There's going to be a whole bunch of legal challenges to the use of such a device just for a few of the reasons already stated in this thread.