Label-free, sequence-specific, inexpensive fluorescent DNA sensors

Using principles of energy transfer more commonly applied to designing solar cells, scientists at the U.S. Department of Energy's Brookhaven National Laboratory have developed a new highly sensitive way to detect specific sequences of DNA.

As described in a paper published in the journal Chemistry of Materials, the method is considerably less costly than other DNA assays and has widespread potential for applications in forensics, medical diagnostics, and the detection of bioterror agents.

"The sensors we've developed use a light-absorbing polymer to amplify the fluorescent signal of a dye that emits light only when it binds between two matched pieces of DNA," said Mircea Cotlet, a physical chemist at Brookhaven's Center for Functional Nanomaterials, who led the research and who is also an adjunct professor at Stony Brook University. The system is sensitive enough to detect individual mismatches between the bases that make up the "rungs" of the twisted-ladder DNA double helix molecule, making it highly specific with no false positives, Cotlet said.

Plus, the method is rapid and requires no expensive equipment, just a conventional laboratory fluorimeter. It has high potential to be made field deployable for rapid analysis of crime-scene evidence and to mount a more knowledgeable, speedy response to bioterror threats.