Masahiko Ogino

Enhancement of fluorescence intensity from an immunoassay chip using high-aspect-ratio nanopillars fabricated by nanoimprinting

High-aspect-ratio structures (nanopillars) were used to enhance the fluorescence intensity of immunoassay chips. Nanoimprinting with elongation phenomenon was applied to fabricate polystyrene nanopillars. Human alpha fetoprotein was detected by a fluorescence immunoassay protocol. Fluorescence intensities were evaluated for areas with nanopillars of different surface areas. The area with nanopillars of 95nm diameter and 4.1μm height showed fluorescence intensity 34 times higher than that of flat areas.

Fabrication of 200-nm Dot Pattern on 15-m-Long Polymer Sheet Using Sheet Nanoimprint Method

Nanoimprint technology is one of the more promising methods for nano-fabrication. The thermal nanoimprint method can fabricate various kinds of thermoplastic materials and its process consists of heating, pressing, cooling, and separation and a lot of research was reported. We proposed and developed a sheet nanoimprint system that enables for continuous treatment of these four basic steps by introducing a belt-shaped nano-mold. We tried to fabricate dot patterns on polymer films by using a sheet nanoimprint method in this work. A 200 nm in diameter and 240 nm tall dots (aspect ratio 1.4) were formed directly onto a 15-m-long polystyrene film. It is important in the field of industrial applications to fabricate nano-scale patterns over a large area with a high throughput. We demonstrated that the sheet nanoimprint is an attractive method for the direct patterning of nano-scale patterns on thermo-plastic films.

Reduction in Viscosity of Quasi-2D-Confined Nanoimprint Resin through the Addition of Fluorine-Containing Monomers: Shear Resonance Study

The fluidity of the resin for the nanoimprint lithography was investigated in a quasi-2D space by the shear resonance measurement, which enables us to measure the viscous property of the resin confined in a nanometer gap between mica surfaces. With this technique, we could observe that the resin fluidity was enhanced by the addition of the fluorine-containing monomer. The fluidity of the resin with the fluorine-containing monomer was maintained until the distance between mica surfaces became smaller than 15 nm, wheras the resin without the fluorine-containing monomer started losing its fluidity when the distance became 30 nm. Two reasons possibly explain the result; (i) the interaction between the resin and mica was reduced by the existence of the fluorine-containing segregated layer at the interface, and (ii) the reduction in viscosity took place by the addition of the fluorine-containing monomer that reduced the degree of chain entanglement in the resin because of its small intermolecular interaction force. The effect of the length of the perfluoroalkyl chain in the fluorine-containing monomer is also discussed.

Developments of nanoimprint technologies and applications

The nanoimprint technology is attractive for the fabrication of nano-scale structures in view of cost and mass production. There are several points for the industrial applications such as pattern formation area, resolution, residual layer thickness, precise control of pattern transfer, lifetime of mold, alignment and so on. A thermal nanoimprint system, which can imprint fine dots on a 300 mm diameter wafer in a single step, is developed. The narrow pith patterns for future storage and IT devices are formed on a polymer layer. A high-aspect nanoprint (Hi-NP) technology forms polymer nanopillars with high aspect ratio. The nanopillars are applied to a bio-chip for the fluorescence immunoassay. The chip is effective in the enhancement of the fluorescence intensities, since the nanopillars enlarge the surface area.

Fluorescence measurement of nanopillars fabricated by high aspect nanoprint technology

In this paper, our aim is to form high aspect structures (nanopillars) by high aspect nanoprint (Hi-NP) technology.