Dip-Pen Nanolithography (DPN)

The Mirkin group published the first research article concerning dip-pen nanolithography (DPN) in Science in 1999.  In this initial proof-of-concept demonstration, an atomic force microscope (AFM) tip coated with an alkanethiol was utilized to direct-write nanoscale molecular line patterns on gold-coated substrates via capillary action with high resolution. This discovery marked a fundamental change in the way researchers think about synthesizing and fabricating miniaturized chemical and biological systems and studying the consequences of miniaturization. DPN provides feature size control, and it was also shown to be materials general. A variety of small molecule inks, biomolecules like DNA, proteins, viruses, and lipids, polymers, and inorganic nanostructures all could be patterned onto metallic as well as insulating and semiconducting substrates. Later, two-dimensional arrays of tips were developed to increase the throughput of DPN, making it possible to pattern in parallel nanoscale features over cm² areas. DPN was the precursor to cantilever-free scanning probe lithographic methods, such as polymer pen lithography (PPL) and beam pen lithography (BPL), subsequently developed by the Mirkin group. The DPN process was originally commercialized by NanoInk (a company founded by Prof. Chad A. Mirkin).