Scientists at Northwestern University have demonstrated a technique that takes gene chips to the limit of miniaturization — down to the nanometer scale of the DNA molecules themselves — and could have a major impact on genomics and proteomics research.
The “dip-pen nanolithography” method uses an atomic force microscope tip as a pen and different single-stranded DNA as inks to produce spots of DNA down to 50 nanometers in diameter. It may make it possible to one day have a gene chip with an array of 100,000 different diagnostic tests in an area the size of the tip of a needle and take only a few seconds to make.

The technique takes advantage of the ability of DNA to self-assemble into a pre-programmable structure.

“Our direct-write patterning of multiple DNA strands also opens up new possibilities for building and studying nanoscale architectures,” said Chad A. Mirkin, director of Northwestern’s Institute for Nanotechnology. “By taking advantage of DNA as a type of biochemical Velcro, we should be able to build a circuit, a catalyst, a sensor or a transistor from the bottom up, instead of the top down.”

Writing nanopatterns with DNA inks