"The amount of optical signal you get usually depends on the thickness of a sample," McDevitt said. "Water, for example, looks clear in a small glass, but is blue in an ocean or a lake. Most modern clinical devices read signals from samples in flat or curved surfaces, which is like trying to see the blue color of water in a glass. It's very difficult."
By comparison, PBNCs give the researchers an ocean of information. "We create an ultrahigh-surface-area microsponge that collects a large amount of material," he said. "The sponge is like a jellyfish with tentacles that capture the biomarkers."
The agarose bead is engineered to become invisible in water. "That makes it an ideal environment to capture biomarkers, because the matrix doesn't get in the way of visualizing the contents. This is a nice use of novel biomaterials that are cheap as dirt, yet yield powerful performance," McDevitt said.
According to previous studies, only a fraction -- less than 10 percent -- of capture antibodies in the "gold standard" ELISA arrays are still active by the time a test begins. By comparison, nearly all of the antibodies in the agarose beads retain their ability to detect and capture biomarkers, McDevitt said.
Ultimately, he said, PBNCs will enable rapid, cost-effective diagnostic tests for patients who are ailing, whether they're in an emergency room, in an ambulance or even while being treated in their own homes. Even better, the chips may someday allow for quick and easy testing of the healthy to look for early warning signs of disease.
|Contact: David Ruth|