Small chip could identify disease

Researchers have confirmed a small chip based on silicon that could be used to make a diagnosis dozens of diseases.
A small drop of blood is drawn through the chip, where disease markers are caught and show up under light.
The device uses the tendency of a fluid to travel through small channels under its own force, in its place of using pumps

The design is simpler, requires less blood be taken, and works more fast than existing "lab on a chip" designs, the team report in Lab on a Chip.

It has a elastic design so that it could be used for a broad range of diagnostics.
Much research in recent years has focused on the chemical and medical possibilities of so-called microfluidic devices at the heart of lab-on-a-chip designs.

These microfluidics contain among dozens and thousands of tiny channels through which fluids can flow, and as micro-manufacturing methods have highly developed, so has the potential complication of microfluidics.

Now, scientists at IBM's research labs in Zurich have developed a cheap lab-on-a-chip that has the potential to diagnose dozens of diseases.

Bind and shine
The device relies on an display of antibody molecules that are planned to latch on to the protein-based molecular markers of disease in blood.
The antibodies are chemically linked to molecules that emit light of a exact colour when illuminated - but only when they have bound to the disease markers.
"There are devices that have been developed in microfluidics to do analysis of proteins, but most of them use active pumping and electrical components," said Luc Gervais, a co-author on the study.

"They're very complex systems; this makes them less easy to use by non-trained personnel - and it makes them a lot more costly to manufacture," Dr Gervais told BBC News.

Instead, the new device exploits capillary action, the tendency of fluids to climb through narrow channels - the same occurrence that drives water into a sponge located on a wet surface.

The speed with which blood is drawn through the chip can be controlled by the design of the micro-channels on the device. Those channels can be designed with unbelievable precision on a silicon chip - something with which IBM has great practice.

The microchannel-patterned chip is then preserved with a special polymer called polydimethylsiloxane, to which the "detector" antibodies easily bond.
unusual antibodies can be placed in a number of distinct channels, making it possible to identify a range of different diseases simultaneously.
Such wide-ranging studies can be done in large analysers, found in the central laboratories of hospitals.

"Typically you'll take a couple of millilitres of blood send it to the central lab and it can take up to an hour or even more to get the results," Dr Gervais said.
"In our case you can get a quantitative analysis of the patient's blood within just a few minutes at the bedside of the patient."
What is more, it can be done with just a few microlitres of blood - a thousand times less - an amount that could be collected with a prick of a finger instead of a syringe.

While the approach will make diagnosis cheaper, co-author Emmanuel Delamarche said the key aspect of the approach is its speed.
"We are giving back precious minutes to doctors so they can make informed and accurate decisions right at the time they need them most to save lives."