Replying to Ruh Roh

Device Offers a Roadside Dope Test

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

By Alexander Gelfand

Tuesday, August 04, 2009

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

[IMG]technologyreview.com/files/31942/biodetect_x220.jpg[/IMG] Quick fix: Philips' drug tester uses a cartridge containing magnetic nanoparticles and a handheld analyzer. Frustrated total internal reflection (FTIR) is used to detect five major recreational drugs in 90 seconds.
Credit: Philips Research

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.

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