( me. Wang’s method allows for an accurat...)Bioelectronic ‘signatures?hold key to DNA mutations

“The novelty of the approach is the combination of the nanocrystal tagging of DNA to create electro-diverse signatures and combining them with a fast, portable, low-cost electronic detection,?Wang says.

To achieve the desired results, Wang and his researchers custom-made several individual nanocrystals, known as quantum dots, from four heavy metal salts of lead, cadmium, zinc and copper. Such nanocrystals were selected owing to their ability to yield distinct electronic signatures, with four well-resolved current peaks. Next, the nanocrystals are piggybacked onto individual DNA bases; these DNA bases ?each carrying a single nanocrystal ?bind to a DNA sample and cause minute electrical current changes in the nanocrystal that can be measured with an electrode. The individual base-conjugated nanocrystals are added sequentially to any DNA sample of interest, generating an electronic “fingerprint?that rapidly identifies all possible combinations of SNPs.

Wang’s results recently were featured as the cover story in the March issue of Analytical Chemistry and were published earlier this winter in the Journal of the American Chemical Society. The article can be found on the Web at (http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/ja043780a).