Massachusetts researchers add nanotransmitters to microfluidic arrays
Technique used to quickly identify pathogens such as anthrax; cuts down on the size of handheld and static detection devices; waveguide and nanoantennas focus light to a spot size smaller than half its wavelength
As long as researchers keep coming up with innovative ways to detect the presence of dangerous pathogens, we will continue to report tirelessly on them. Such is our oath and our pledge, and will not fail you. Consider the latest method to cross our desk: a microfluidic chip that performs fast DNA sequencing to rapidly identify bacteria, especially anthrax. Researchers at Woburn, Massachusetts-based U.S. Genomics and the Cambridge, Massachusetts-based Draper Laboratory, say the approach may be simple enough that a device that employs it could be used in airport screening and other security checkpoints.
In keeping with most DNA sequencing approaches, the researchers have created a database of unique base sequence patterns known as “bar code panels” attributable to various bacterial strains. (Due to DHS security concerns, the particular germs are a secret.) After the DNA is extracted from a sample and labeled with a flouresecent tag particular to the sequence of the suspected substance, single molecules are fed into a microfluidic chip, where hydrostatic pressure pulls them through a narrow channel on which is focussed a narrow beam of light. When the DNA passes over the beam, the labels fluoresce. The resulting flashes are recorded as a bar code and compared to the database.
This is a fine technique, but not in itself revolutionary. What makes the U.S. Genomics-Draper approach interesting is that it uses a waveguide and nanoantennas to focus the light to a spot size much smaller than half its wavelength. The result is far higher resolution and the ability to read shorter strands with greater accuracy. Moreover, the use of nanoantennas rather than a lens means the chips are smaller and more easily protected with ruggedizing features. According to scientist Jeff Krogmeier, the end result might be a decive “that would sit in an airport, mall, or other public area and continuously monitor the air. We just need a few molecules [of DNA],” says Krogmeier.
-read more in Katherine Bourzac’s Technology Review report
