Nanografting to Produce Tiny DNA Microarrays

The report was published in the August 2002 issue of Nano Letters.

The technique, called nanografting, can be used to generate patterns of DNA that are up to a thousand times smaller than those in commercially available microarrays. The patterns were made by coating a gold film with long, closely packed thiol molecules. The thiols were bound to the gold through a sulfur atom at one end, which allowed them to maintain a vertical configuration. An atomic force microscope probe was used to scrape away some of the thiols. Short oligonucleotide sequences labeled with thiols at one end were attached to the exposed gold, leaving the strands of chemically active DNA protruding above the thiol layer.

Using this method, investigators from the University of California, Davis (USA; www.ucdavis.edu), were able to draw lines as fine as 15 nanometers across by 150 nanometers long--equivalent to eight DNA molecules across.

Dr. Gang-yu Liv, a chemist at UC, Davis, said, "We believe these are the smallest nanostructures of DNA yet made.”



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