Now chemists at Northwestern University have set a DNA detection sensitivity record for a diagnostic method that is not based on PCR -- giving PCR a legitimate rival for the first time. Their results were published online today (April 27) by the Journal of the American Chemical Society (JACS).
"We are the first to demonstrate technology that can compete with -- and beat -- PCR in many of the relevant categories," said Chad A. Mirkin, director of Northwestern's Institute for Nanotechnology, who led the research team. "Nanoscience has made this possible. Our alternative method promises to bring diagnostics to places PCR is unlikely to go -- the battlefield, the post office, a Third World village, the hospital and, perhaps ultimately, the home."
The new selective and ultra-sensitive technology, which is based on gold nanoparticles and DNA, is easier to use, considerably faster, more accurate and less expensive than PCR, making it a leading candidate for use in point-of-care diagnostics. The method, called bio-bar-code amplification (BCA), can test a small sample and quickly deliver an accurate result. BCA also can scan a sample for many different disease targets simultaneously.
The Northwestern team has demonstrated that the BCA method can detect as few as 10 DNA molecules in an entire sample in a matter of minutes, making it as sensitive as PCR. The technology is highly selective, capable of differentiating single-base mismatches and thereby reducing false positives.
In their experiments, the scientists used the anthrax lethal factor, which is important for bioterrorism and has be
Contact: Megan Fellman