Portable generic risk detection

A portable biosensing device based on micro- and nanotechnologies is expected to help doctors rapidly and accurately forewarn patients of their genetic risk of developing diseases such as cancer.

Currently being developed by the IST project Optonanogen, a prototype of the system will initially be used to determine mutations of the BRCA1 gene that are responsible for between 2.5 and 5% of the incidence of breast cancer in women.

The final system, however, could be used to detect virtually any genetic anomaly as well as proteins linked to viruses, chemical contamination in food or water pollution.

"There is a broad variety of applications for this system, although the main market is in biomedicine," explains Optonanogen coordinator Laura Lechuga at the National Microelectronics Centre in Spain.

"Though commercial biosensing systems exist they are larger and designed to be used in laboratories. We are the first to develop a fully integrated system on a small scale in this field."

The final device will be roughly the size of a human hand, allowing it to be used in doctors' surgeries to determine the genetic predisposition of a patient to certain diseases in a matter of minutes.

This compares to the hours or even days it can take to carry out the same analysis in a laboratory, which is generally only used to test high risk groups such as women with a family history of breast cancer.

To detect genetic mutations the system uses an array of 20 microcantilevers coated in nucleic acid that react when they come into contact with a DNA sample displaying the genetic anomaly.

The sample is injected into the device via a microfluidic header and the deflection of the cantilevers - by as little as 0.1 to 0.5 nanometres - is picked up by a photodetector array based on the reflection of light off the cantilevers from vertical cavity surface emission lasers (VCSELs).

After evaluation trials this year, a commercial variant of the system is likely to be produced within one or two years.