June 10, 2002 — Using an atomic force microscope tip as a pen and different single-stranded DNA as inks, scientists at Northwestern University have demonstrated a technique that could lead to the ultimate high-density gene chip because it takes gene chips to the limit of miniaturization — down to the scale of the DNA molecules themselves, according to a university news release.

This development, which uses the same tool to write patterns and read the results on the nanometer scale, could have an enormous impact on genomics and proteomics research.

Results of the DNA patterning on both gold and silicon oxide, which is important for electronic and optical materials applications, was published in the June 7 issue of the journal Science.

“With this new tool, we can take a normal chip that’s made and sold today for studying a problem in genomics and miniaturize it to 1/100,000th of its size,” said Chad A. Mirkin, director of Northwestern’s Institute for Nanotechnology, who led the research team.

“In a normal chip with 100,000 different spots of DNA, each spot is 20 to 40 micrometers in diameter. Using state-of-the-art dip-pen nanolithography we can prepare 100,000 DNA spots in the area occupied by a single spot in a conventional gene chip.”