72
  • Emailarticle
  • Writecomment

A Chip Away

A new biochip diagnoses illnesses before the first symptoms appear.

By JANE AMMESON

 


    Biologists at Argonne National Laboratory have designed a biochip capable of diagnosing illnesses even before patients exhibit symptoms. Biologist Dr. Daniel Schabacker leads the development of the technology, which will provide rapid diagnosis early on while eliminating the need for time- consuming confirmatory tests. Chartered in 1946 and the country’s first national laboratory, Argonne, located in Argonne, Illinois, is one of the U.S. Department of Energy’s largest research centers. A direct descendant of the University of Chicago's Metallurgical Laboratory, where on Dec. 2, 1942, Enrico Fermi and some 50 colleagues created the world’s first controlled nuclear chain reaction, Argonne continues its collaborative approach to research. Schabacker, who holds a PhD in immunology from the University of Illinois at Urbana/Champaign, discussed his new biochip technology.


    What can these biochips do? A biochip is used to perform several tests in parallel at the same time. For example, one of our diagnostic partners is developing a biochip capable of identifying the cause of common respiratory syndromes. Instead of running 10 different tests for the most common causes, a biochip can combine all these into a single test. This greatly reduces the amount of human sample required while screening for multiple causative agents, speeding diagnosis.
   

    How does that apply to someone who is sick? With any diagnostic test it is important not only to provide a timely diagnosis, but also an accurate one.  Some tests currently in use may be marginally quicker than ours, but require time-consuming and expensive additional testing to validate the rapid diagnosis. If someone shows up at the hospital and they’re sick with an upper respiratory infection, the first thing a doctor wants to know is whether the infection is viral or bacterial. Ideally, they’d like to have a single test they can run that rapidly identifies exactly which disease the person has from a dozen top targets.
   

Just how small are these biochips?

Small. Our biochips contain 100 to 1000 dots located within a one centimeter by one centimeter area. Each dot is about the thickness of human hair.

What do the dots or drops do?

Each drop is a test containing a different probe or capture agent, whether it’s protein, an antibody or nucleic acid. For instance if influenza A is present in a sample, it will be captured by the dot containing a probe specific for influenza A. This dot will “light up” within the imaging system, providing the diagnosis of an influenza A infection.

So if you have 1000 drops in a diagnostic test, do you test for a 1000 different things?

No, we incorporate several control elements and use internal redundancy in order to provide the most accurate output. Therefore a test for 10 different infectious agents may require 100 dots. 
Why so much redundancy? If we’re looking for anthrax, for example,  many rapid tests are inaccurate. In the mail room tests for anthrax, bacteria similar to Bacillus anthracis can result in positive results. You might find anthrax with those tests, but it may also be non-pathogenic bacteria similar to the bacteria that cause anthrax commonly found in the environment. In order to avoid this problem, we don’t use just one probe; we have different probes specific for different portions of the bacteria.  

How fast are the tests?

We set out to develop a rapid test capable of identifying multiple targets within 15 minutes to an hour that is also highly accurate. There is usually a trade off between speed, sensitivity and accuracy. The most sensitive and accurate tests usually take days to provide an answer, while the very rapid tests requiring only a few minutes are usually less sensitive and inaccurate. Our goal was to develop a test that is highly accurate and sensitive, but could provide an answer in less than an hour.

What was Argonne’s role in creating these biochips?

The biochip actually came out of Russia about 10 years ago. We were able to prove the Russian concept in a laboratory setting, but the manufacturing process needed to be scalable to be commercially viable. The role of the national laboratories is to transition cutting-edge technology to the private sector in order to bring them to market. The technology for manufacturing the biochips in a commercial setting was developed at Argonne. Scientists at Argonne also developed a field-portable imaging system that can be set up in the field or in the back of a truck.  
What can be tested? Any test that you can imagine can be performed on the biochip.

How do you get the information from the patient to the biochip? 

Our tests use the same samples as existing tests, mainly minimally invasive to non-invasive body fluids like blood, serum, nasal aspirates, sputum, etc. These fluids are placed directly on the biochip to perform the test.

Which diseases do you anticipate the biochip being able to diagnose?

Current research is focused on the detection of common infectious diseases, drug-resistant infectious diseases and cancer. There really is no limit to what the biochip can be used to detect.

How do you make this technology available for use?

The biochip technology has been licensed to three companies and the imaging system has been licensed to one company. Akonni Biosystems is developing human diagnostics, Safeguard Biosystems is focused on veterinary diagnostics, and Eprogen is focused on cancer biomarker discovery. Aurora Photonics is developing the biochip imager for research and diagnostic applications. It is exciting because we see the technology progress with our four licensees. You can see that they’re getting closer and closer to their goals.

Published: February 08, 2009
Issue: February 2009 Design Issue