Chip That Measures Proteins

A team of scientists from Caltech (California Institute of Technology) have developed a “barcode chip” that represents e new milestone in diagnostic medical testing. This chip uses very little blood to calculate the concentrations for dozens of proteins. Among these proteins, the ones that mark presence of heart diseases and cancer are measured. And all this in only ten minutes.

As it is published Nature Biotechnology, the barcode chip (also called IBBC) is as small as a microscope slide and has a glass base with a silicone rubber coating. It’s surface contains a microfluidics circuit. That microfluidics circuit is a system of small channels trough which the blood is introduced. The chip separates the protein-rich blood plasma and then uses it to measures a wide panel of proteins.

In hospitals and diagnostic centers of the present, whole vials of blood are taken from the patient, then centrifuged to obtain the plasma and then the plasma is searched for specific proteins (usually one at the time).

James R. Heath, the man that led this project, talks about the importance of this chip :

“(in the present)The process is labor intensive, and even if the person doing the testing hurries, the tests will still take a few hours to complete. We wanted to dramatically lower the cost of such measurements, by orders of magnitude. We measure many proteins for the cost of one. Furthermore, if you reduce the time it takes for the test, the test is cheaper, since time is money. With our barcode chip, we can go from pinprick to results in less than 10 minutes.”

This chip has even more advantages : it can analyze the blood of up to 8 patients simultaneously with each test providing results for multiple proteins. Current devices can measure up to a dozen proteins with a single drop of blood, but their aim is to reach a hundred proteins per fingerprick of blood. ”We are aiming to measure 100 proteins per fingerprick within a year or so. It’s a pretty enabling technology,” Heath says.

In order to perform a test, a single drop of blood is placed in the chip’s inlet, and then the chip is squeezed slightly to push the blood trough a channel. As blood runs trough the main channel, plasma deviates and runs trough narrow channels that separate from the main channel.

Now we get to the part of the process that gives this chip it’s name : the barcodes. These barcodes are series of lines, each one possessing a different antibody that captures specific proteins from the plasma that passes trough. Each barcode, when developed will emit a red glow. A bright glow means more proteins, while a dim glow stands for a low concentration of proteins.

In the study, researchers used this chip to identify variation of the hormone that women produce during pregnancy, as well as several proteins that indicate breast cancer and prostate cancer.

The chip is now in the stage of human clinical trails on patients that suffer from an aggressive form of brain tumor, called glioblastoma. But the chip is also used in studies of healthy individuals in order to show how exercise and diet can change the composition and concentrations of proteins.