Dip Pen Nanolithography

NSF Propels Research On Dip-Pen Nanolithography® (DPN®) – The World’s Smallest Printing Tool

Think about the last time you wrote with a pen. Now, imagine shrinking down the width of the ink trail from that pen to the size of a few molecules – less than 100 nanometers wide. While it may sound far-fetched, this is what Dr. Chad Mirkin and colleagues at Northwestern University, with financial support from the National Science Foundation (NSF), have done with the creation of Dip Pen Nanolithography® (DPN®).

This versatile nanolithography method can be used to directly ‘write’ molecules onto all types of matter – from gold to germanium. With up to 55 thousand pens arranged on a small wafer, an image – even one as detailed as a person’s face – can be duplicated onto any surface. DPN® could propel advances in fields ranging from medicine to national security.

This method was developed at the Northwestern Nanoscale Science and Engineering Center, which is funded primarily by the Nanoscale Science and Engineering Initiative of the NSF. In 2002, DPN® technology was licensed to NanoInk, a venture-backed company. NanoInk has commercialized many products based on the original DPN® design, and the technology is now used in hundreds of laboratories worldwide.

Dr. Mirkin initially thought of the idea for DPN® when his group was studying water transport processing involving atomic force microscopes (AFM) – high resolution microscopes that enable researchers to determine the topology and chemical identity of a surface at the nanoscale level. He thought AFM could be a useful synthetic device. Based on this idea, the research team at Northwestern developed a technique that transfers ‘ink’ – or molecules – from an AFM tip to a surface. The driving force behind this transfer is a chemical reaction between the transferred molecules and the surface.

The first tool commercialized by NanoInk, the NScriptorTMDPN® System, allows researchers to use a common microscope known as the scanning probe microscope for nanolithography. This system is used by hundreds of laboratories in 22 different countries. DPN® has many potential future applications, from designing gene chips used to detect diseases or mini-code chips that store or hide large amounts of information.

In addition to NSF funding, Dr. Mirkin and his group have received Federal funding from the Defense Advanced Research Projects Agency (DARPA) and the Air Force Office of Science Research (AFOSR).