Dip-pen Nanolithography Method Research Articles

Dip-Pen Nanolithography Method for Fabrication of Biofunctionalized Magnetic Nanodiscs Applied in Medicine

The magnetic properties of ferromagnetic nanodiscs coated with gold, manufactured using the Dip-Pen Nanolithography method, and were studied by atomic-force and magnetic force microscopy methods. The magnetic discs (dots) are represented as nanoagents (nanorobots) applied in medicine for the cancer cell destruction. The motivation of this work stem from the necessity of the understanding of the magnetization distribution in ferromagnetic discs that is crucial for their application in biomedicine. We have performed the theoretical calculations in order to compare the theoretical image contrast to experimental results. Herein, we report about the fabrication and analysis of biocompatible ferromagnetic nanodiscs with the homogenous magnetized state.

Alternative Technology for Creating Nanostructures Using Dip Pen Nanolithography

For modern microelectronics, at the present time, the technologies of consciousness smart structures play an important role, which can provide accuracy, stability and high quality of the structures. Submicron lithography methods are quite expensive and have natural size limitations, not allowing the production of structures with an extremely small lateral limitation. Therefore, an intensive search was conducted for alternative methods for creating submicron resolution structures. Especially attractive one is the possibility of self-organization effects utilization, where the nanostructure of a certain size is formed under the influence of internal forces. The dip pen nanolithography method based on a scanning probe microscope uses a directwrite technology and allows one to carry out a playback of small size structures with high accuracy. In the experiment, a substrate coated with Au (15 nm) using a DPN technique is applied to the polymer to form a desired pattern nano-sized channel. The experiment was conducted using a pointed probe SiN, coated MHA-Acetonitrile, on the Si(111)/Fe3Si/Au structure.

Highly conductive indium nanowires deposited on silicon by dip-pen nanolithography

In this paper, we developed a new dip-pen nanolithography (DPN) method. Using this method, we fabricated conductive nanowires with diameters of 30–50 nm on silicon substrates. To accomplish this, indium was transferred from an atomic force microscopy tip to the surface by applying a potential difference between the tip and substrate. The fabricated indium nanowires were several micrometers in length. Unlike thermal DPN, our DPN method hardly oxidized the indium, producing nanowires with conductivities from 5.7 × 10−3 to 4 × 10−2 Ω cm.

Direct-Write Patterning of Bacterial Cells by Dip-Pen Nanolithography

The ability of dip-pen nanolithography (DPN) to generate nano- or microarrays of soft or hard materials (e.g., small molecules, DNA, proteins, nanoparticles, sols, and polymers) in a direct-write manner has been widely demonstrated. The transporting of large-sized ink materials such as bacteria, however, remains a significant challenge with this technique. The size limitation of the water meniscus formed between the DPN tip and the solid surface becomes a bottleneck in such diffusion-based molecular transport experiments. Herein, we report a straightforward "stamp-on" DPN method that uses a nanostructured poly(2-methyl-2-oxazoline) hydrogel-coated tip and carrier agents to generate patterns of micrometer-sized Escherichia coli JM 109 bacterial cells. We demonstrate that this approach enables the deposition of a single bacterial cell array on a solid surface or arrays of layers of multiple cells by modulating the viscosity of the "ink" solution. Fluorescence microscopy images indicated that the deposited bacterial cells were kept alive on Luria-Bertani-agar layered solid surfaces after DPN patterning.

Electric-Field-Assisted Dip-Pen Nanolithography on Poly(4-vinylpyridine) (P4VP) Thin Films

Dip-pen nanolithography (DPN) has attracted increased attention for its ability to generate nanometer-scale patterns on solid surface using an “ink”-coated atomic force microscope (AFM) tip. In contrast to this conventional anchoring-molecules procedure, nanopatterns can also be created by triggering the structural response of the proper substrate. In one approach, the delivery of acidic buffer from the tip into a poly(4-vinylpyridine) (P4VP) thin film (while the tip is being laterally moved, in a raster fashion, along a preprogrammed pattern) leads to the polymer swelling in response to the local protonation. This practice, however, has suffered from a lack of consistency due to the potentially many factors influencing the pattern formation. Herein we report that a more reliable strategy for well controlling the protonation process results when applying an electric field between the AFM tip and the sample. We demonstrate the improved capabilities of the electric-field-assisted DPN method towards reproducibly and reliably fabricating nanostructures by taking advantage of the responsive characteristics (i.e. swelling) of P4VP. Our work includes a systematic study of pattern fabrication under different patterning parameters (mainly the applied bias and contact force) and, very important, provides evidence of the reversible characteristic of the pattern formation process.

Dip Pen Nanolithography®: A “Desktop Nanofab™” Approach Using High‐Throughput Flexible Nanopatterning

The ability to perform controllable nanopatterning with a broad range of "inks" at ambient conditions is a key aspect of the dip pen nanolithography (DPN) technique. The traditional ink system to demonstrate DPN is n-alkanethiols on a gold substrate, but the DPN method has found numerous other applications since. This article is meant to outline recent advances in the DPN toolkit, both in terms of research and patterning technology, and to discuss applications of DPN as a viable nanofabrication method. We will summarize new DPN developments, and introduce our concept of the "Desktop Nanofab." In addition, we outline our efforts to commercialize DPN as a viable nanofabrication technique by demonstrating massively parallel nanopatterning with the 55,000 tip 2D nano PrintArray. This demonstrates our ability to overcome the serial nature of DPN patterning and enable high-throughput nanofabrication.

Novel Ultrananocrystalline Diamond Probes for High‐Resolution Low‐Wear Nanolithographic Techniques

A hard, low-wear probe for contact-mode writing techniques, such as dip-pen nanolithography (DPN), was fabricated using ultrananocrystalline diamond (UNCD). Molding within anisotropically etched and oxidized pyramidal pits in silicon was used to obtain diamond tips with radii down to 30 nm through growth of UNCD films followed by selective etching of the silicon template substrate. The probes were monolithically integrated with diamond cantilevers and subsequently integrated into a chip body obtained by metal electroforming. The probes were characterized in terms of their mechanical properties, wear, and atomic force microscopy imaging capabilities. The developed probes performed exceptionally well in DPN molecular writing/imaging mode. Furthermore, the integration of UNCD films with appropriate substrates and the use of directed microfabrication techniques are particularly suitable for fabrication of one- and two-dimensional arrays of probes that can be used for massive parallel fabrication of nanostructures by the DPN method.

Patterning PETN and HMX using Dip Pen Nanolithography

AbstractRecently there has been a focused effort to develop reliable nanoscopic writing and reading capabilities. Dip-pen nanolithography (DPN) has emerged as a convenient method to deliver nanoscale materials onto a substrate by leveraging scanning probe microscopy capability. A new application for the DPN method is the field of microdetonics which is the microscale decomposition and study of reactions of explosives. Results are presented for patterning pentaerythritol tetranitrate (PETN) and cyclotetramethylene tetranitramine (HMX) on silicon and mica substrates. The ultimate goal is to pattern both energetic materials in nanoscale registry and investigate their reaction and decomposition at the nanoscale due to heating or shock initiation. In addition to patterning of high explosives, a discussion on the effect of surface energy on patterning rates is investigated. This knowledge will be applicable to inks beyond high explosives.