New Tools and Applications Based on Dip-Pen Nanolithography

Dip-Pen Nanolithography (DPN) is a novel lithographic technique based on scanning probe microscopy (SPM), with unique capabilities that cannot be achieved by conventional lithographic methods 1-3. In particular, as summarized in Fig. peb3, DPN offers the ability to "direct-write" patterning with various types of molecular “inks” (e.g. organic small molecules, DNA, proteins, inorganic molecules, or polymers) on diverse substrates with ultrahigh spatial resolution (10 nm line-width resolution and 5 nm spatial resolution), using the controlled contact of an SPM tip with a substrate, through an aqueous meniscus, to transfer molecules directly to the area under the tip. Thus DPN provides a unique opportunity for constructing modified surfaces with a large degree of complexity. DPN can also be performed with probe arrays for large throughput. It has a particular promise for combinatorial searches, for instance to create graded function arrays for exploration of cellular behavior 4-8[peb3]. Inorganic processes can also benefit from the use of this technique. Transition-metal oxides display a plethora of collective quantum phenomena, ranging from high-Tc superconductivity in layered cuprates, colossal magnetoresistance (CMR) in perovskite manganites, to the coexistence of magnetism and ferroelectricity—termed multiferroicity 9-11 [peb4]. Understanding and controlling chemical and physical properties of the surfaces of these complex oxides is necessary to move towards practical technological applications of these fascinating phenomena. Dip-Pen Nanolithography can aid this development by growing complex nano-oxides in chosen patterns on disparate substrates. In addition, SPM in the same instrument can be used to observe the physical and chemical behavior in the patterned area 9,12. The scientific goal of this new capability is to explore biology, chemistry, and physics of soft and hard material nanostructures having sub-100 nanometer features, and to further develop novel nanolithographic tools for fabricating such structures. Including collaboration among ~20 Rutgers researchers across several departments and schools, it will be administered through the Institute for Advanced Materials and Devices and Nanotechnology (IAMDN), and located in a new chemistry oriented user facility in the new chemistry building currently under construction. This DPN system will serve as an advanced component of the lithographic facility (photolithography and nanoimprinting)11,13 and high-resolution microscopy facility at Rutgers University, to be shared with outside users within the NNCI umbrella.