Device detects bioterror agents with bike reflector material

US scientists are hoping victims of bioterror attacks could have their conditions diagnosed more quickly using technology developed from the reflective material used on bikes.

Researchers from the University of Houston are developing a device that contains microscopic versions of the retroreflectors used by cyclists to make themselves more visible on the roads, and that can determine which disease a person is infected with.

The lab-on-a-chip technology distributes fluid samples from a patient into several tiny channels each containing a tiny retroreflector, different parts of which appear dark when disease-causing microbes are in the sample – a change that can be quickly detected using simple optical devices.

‘Our goal is the development of an ultrasensitive, all-in-one device that can quickly tell first-responders exactly which disease-causing microbe has been used in a bioterrorism attack,’ said research leader Dr Richard Willso, who presented his work at this week’s National Meeting & Exposition of the American Chemical Society.

‘In the most likely kind of attack, large numbers of people would start getting sick with symptoms that could be from multiple infectious agents. But which one?

‘The availability of an instrument capable of detecting several agents simultaneously would greatly enhance our response to a possible bioterror attack or the emergence of a disease not often seen here.’

The researchers argue that retroreflectors may be the most visually detectable devices ever made by humanity because they reflect light directly back to its source in a way that produces extreme brightness – a version of the technology left on the Moon by Apollo 11 astronauts is still used to study its orbit.

Willson’s collaborator Paul Ruchhoeft has developed a way of making retroreflectors small enough to fit more than 200 in a space the size of a full stop.

The researchers said that incorporating these reflectors into a lab-on-a-chip device means there is no need for expensive, complex optics to detect the light signals used to analyse samples, which also don’t need to be specially prepared.

‘Right now, we have seven channels in our device,’ said researcher Balakrishnan Raja ‘So we can test for seven different infections at once, but we could make more channels. That’s one of our long-term goals — to multiplex the device and detect many pathogens at once.’

The team have demonstrated that the device has clinically useful sensitivity on samples containing Rickettsia conorii, a bioterrorism threat that causes Mediterranean spotted fever.

A new version of the technology that involves retroreflector cubes that can be suspended in samples of fluid is due to be tested on samples of norovirus, the winter vomiting bug. Another version intended for rapid diagnosis in doctors’ clinics is also on the cards.