June 18th, 2015

Northwestern University's International Institute for Nanotechnology (IIN) has received a five-year, $8.5 million grant from the U.S. Department of Defense's competitive Multidisciplinary University Research Initiative (MURI) program to develop a "4-dimensional printer" -- the next generation of printing technology for the scientific world.

Once developed, the 4-D printer, operating on the nanoscale, will be used to construct new devices for research in chemistry, materials sciences and U.S. defense-related areas that could lead to new chemical and biological sensors, catalysts, microchip designs and materials designed to respond to specific materials or signals.
"This research promises to bring transformative advancement to the development of biosensors, adaptive optics, artificially engineered tissues and more by utilizing nanotechnology," said IIN director and chemist Chad A. Mirkin, who is leading the multi-institution project. Mirkin is the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences.
The award, issued by the Air Force Office of Scientific Research, supports a team of experts from Northwestern, the University of Miami, the University of California, San Diego, and the University of Maryland.
In science, "printing" encodes information at specific locations on a material's surface, similar to how we print words on paper with ink. The 4-dimensional printer will consist of millions of tiny elastomeric "pens" that can be used individually and independently to create nanometer-size features composed of hard or soft materials.
The information encoded can be in the form of materials with a defined set of chemical and physical properties. The printing speed and resolution determine the amount and complexity of the information that can be encoded.
Progress in fields ranging from biology to chemical sensing to computing currently are limited by the lack of low-cost equipment that can perform high-resolution printing and 3-dimensional patterning on hard materials (e.g., metals and semiconductors) and soft materials (e.g., organic and biological materials) at nanometer resolution (approximately 1,000 times smaller than the width of a human hair).
"Ultimately, the 4-D printer will provide a foundation for a new generation of tools to develop novel architectures, wherein the hard materials that form the functional components of electronics can be merged with biological or soft materials," said Milan Mrksich, a co-principal investigator on the grant.
Mrksich is the Henry Wade Rogers Professor of Biomedical Engineering, Chemistry and Cell and Molecular Biology, with appointments in the McCormick School of Engineering and Applied Science, Weinberg and Northwestern University Feinberg School of Medicine.
"Researchers at Northwestern's International Institute for Nanotechnology have a history of developing the state-of-the-art tools enabling nanotechnology," said Jay Walsh, vice president for research at Northwestern. "This new 4-D printing effort represents a wonderful example of a multi-institutional collaboration that capitalizes on such expertise and couples it with expertise at other institutions."
Mirkin invented and developed one of the first molecular printing techniques: dip-pen nanolithography (DPN). This technique uses an atomic force microscope and a sharp tip to deliver small packets of molecules to a surface. The molecules are designed to react with the surface to form stable single-molecule-thick structures. In 2012, National Geographic named DPN one of the "100 Scientific Discoveries That Changed the World."
The International Institute for Nanotechnology is an umbrella organization that represents and unites over $800 million in nanotechnology research, education and supporting infrastructure.