| TECHNOLOGY |
Gene-chip technology may have just gotten a boost, thanks to developments in DNA detection schemes. Authors have devised a technique in which 50- and 100-nm-sized gold particles serve as colored probes to selectively detect two different DNA target sequences in a single solution. Demonstrating the procedure, the group cohybridizes oligonucleotide-modified particles and oligonucleotide targets to arrays of DNA attached to glass slides. Light (h) scattered from the particles is imaged as bright spots on a dark background; the 50-nm particles scatter green light, and 100-nm particles appear orange. The chemists assessed the method's selectivity in temperature-dependency tests using targets with a single base-pair mismatch. Slightly mismatched targets (green) dissociate over a narrow range (55 to 60 C) as indicated by a color change that is readily visible in real time. The technique should be extendable to additional colors using nanoparticles of various sizes and compositions, the researchers note. They add that the method's selectivity may be suitable for studying single-nucleotide polymorphism and genetic disease mutations
|