Chip smells with ionic mobilities grating

Tom Shelley reports on the emergence of a technology that allows multiple chemical species to be detected by a small, chip based device

Measuring the mobilities of different molecules within a small space on a chip allows the rapid detection of a wide range of chemical species. Already the basis of techniques being used by the military to detect chemical and biological warfare agents, it has the potential to form the basis of a wide range of much lower cost devices for civilian applications. Applications range from early fire detection, through maintenance of air quality in air conditioning systems to drug breathalysers and diagnostic equipment capable of being carried in a doctor's bag. Owlstone, based in Cambridge, takes its name from a gemstone embedded in the bottom of a silver chalice belonging to 14th century Pope Pius II. The stone would change colour if the drink were poisoned with arsenic. The modern version, vastly more versatile, and potentially much cheaper, is the brainchild of three Cambridge graduates, Billy Boyle, Andrew Koehl and David Ruiz-Alonso. Its mode of operation is to ionise molecules and analyse their behaviour in an electric field in an air filled cavity one tenth of a millimetre across. The behaviour of individual molecules is affected by their shape and mass. A typical civilian application might be early fire detection in a public building, responding to the presence of molecules released by heated furnishings or building materials, before smoke is visible or reaches sensors. Billy Boyle points out that since the core technology is generic and relevant to the detection of many substances, the same sensors could also monitor temperature and air quality to control air conditioning systems, or noxious chemicals released either by accident or deliberately. Chip based detectors could also detect illegal substances on the breath of motorists, or substances produced by diabetes, cancerous tumours or heart disease. The sensors could be attached to a PDA or mobile phone in the hands of, or connected to, a doctor. Previous sets of instruments to undertake such work have gradually come down from room size and costs of hundreds of thousands of pounds, the ghetto blaster size with £10,000 price tags. The new units, on the other hand are button sized, and in volume production might cost as little as £10 each or less. Owlstone presently exists as a start-up company in the St John's Innovation Centre in Cambridge. First round funding of $2 million was received from Advance Nanotech in May 2004. In October 2004, the company won a Small Business Innovation Research award from the US Defence Threat Reduction Agency. The first commercial devices are expected to come to market in 2006. Owlstone Email owlstone Pointers * Device is button sized but can nonetheless distinguish between a wide range of chemical substances * Volume production cost may eventually be £10 each or less * Commercial production is expected to commence in 2006