Food-borne diseases could soon be detected using a lab-on-chip device made possible through microelectromechanical systems (MEMS) technology.

A team of European researchers has created a prototype system to prepare samples and perform DNA tests on bacteria in a portable, cost-effective chip.

The EU-funded OptoLabCard project is based at the Spanish research centre Ikerlan.

What sets the OptoLabCard prototype apart from previous devices is the material used to manufacture the components of the chip, and the way in which samples are prepared prior to testing.

Using a single material for most components – a negative thick photoresist, makes the chips simpler and cheaper to produce.

The chip itself is disposable, while a reader or base unit contains all the electronics and optics. Meanwhile, incorporating sample preparation into the chip means that users can effectively replicate laboratory processes out in the field.

In order to detect the presence of bacteria, a reliable sample is essential. Rubbing a swab across a chicken carcass, for example, might produce a sample containing as few as ten bacteria, an amount that size could go undetected once transferred into the device. The inability to provide a representative sample could lead to the bird, or the entire batch to be deemed clean, when actually, the meat may be covered with dangerous pathogens.

To overcome the problem and to improve detection accuracy, the team at Ikerlan incorporated a method of concentrating the sample before testing. They used magnetophoresis and the polymerase chain reaction (PCR) technique. PCR is a well established method of replicating DNA to create higher concentrations.

Jesús Ruano-López, OptoLabProject co-ordinator, explained “By using PCR for sample preparation, we can create more concentrated bacteria samples, and because it works with DNA, it means that the same device can be used to detect many different types of bacteria and diseases.”

So far, the device has been used experimentally to detect salmonella in faecal samples taken from hospitals, and will soon be used in Denmark to test for campylobacter on chicken farms.

Ruano-López concluded: “The uses for these devices are almost endless… and the market is huge.”