In the current incarnation of the company’s DNA chips, the bar-code patterns are read at a resolution of 0.5 micrometers. The version being developed by U.S. Genomics and Draper Laboratory uses a waveguide and nanoantennas to focus the light to a spot size much smaller than half its wavelength, giving far higher resolution and allowing the device to read shorter strands with greater accuracy. What’s more, the light from these antennas is 10 times as intense, which means a stronger signal, says Jonathan Bernstein, a Draper researcher working on the project. And focusing the light with the nanoantennas instead of with a lens means the chips are more compact and rugged.
Krogmeier says the U.S. Department of Homeland Security is interested not only in identifying pathogens, but also in identifying whether they’ve been tampered with. A bioterrorist trying to make anthrax or E. coli more deadly or more easily dispersed would often attempt to do so by adding long stretches of DNA from another organism. The U.S. Genomics chip, says Krogmeier, would be able to detect such tampering.
Bernstein says that the microfluidic channels could also be useful for looking at molecules besides DNA. Common lab techniques like PCR, the process used to make many copies of a single strand of DNA, simply do not exist for studying RNA and proteins; as a result, they are harder to identify and manipulate. “Most of the cell is not DNA,” says Bernstein. Something like the microfluidic chip he has developing for U.S. Genomics, he says, could be very helpful for studying other biological molecules.