ELISA is a common immune-system-based assay that uses enzymes linked to an antibody or antigen as a marker for picking out specific proteins. For example, it is used as a diagnostic test to determine exposure to infectious agents, such as HIV, by identifying antibodies present in a blood sample.
The sensitivity of detecting molecules by the new method, called FACTT, short for Florescent Amplification Catalyzed by T7-polymerase Technique, is five orders of magnitude (100,000 times) greater than that of ELISA, the Penn researchers found.
Senior author Mark I. Greene MD, PhD, the John Eckman Professor of Medical Science, Hongtao Zhang, PhD research specialist; Xin Cheng, PhD, research investigator, and Mark Richter, a research technician in Greene's lab, report their findings in the advanced online publication of Nature Medicine.
"The current ELISA tests can only detect proteins when they are in high abundance," says Zhang. "But the problem is that many of the functional proteins ?those that have a role in determining your health ?exist in very low amounts until diseases are apparent and cannot be detected or measured at early stages of medical pathology. It was important to develop a technique that can detect these rare molecules to detect abnormalities at an early stage."
The FACTT technology uses a different enzyme amplification system so quantitative signals can be obtained from even a few protein molecules compared to ELISA. "The t
Source:University of Pennsylvania School of Medicine