Nanotechnology

Method for printing micro contact pattern with hydrogel as template and colloid crystal as writing ink

Abstract

The invention relates to a micro contact pattern printing method with hydrogel as template and colloid and crystal as ink, comprising the steps that: diluting monodisperse silicon dioxide, or polystyrene, or polymethyl methacrylate microspheres with deionized water; evenly diluting and mixing the mixture of acrylamide and methylene bisacrylamide with a rate of mass to volume of 10% to the rate of3% to 6% while adding an initiator azobisisobutyronitrile; obtaining hydrogel through irradiation and polymerization for 40 minutes by a high-voltage mercury lamp under four DEG C; peeling the hydrogel off a die, sufficiently washing the hydrogel and storing the hydrogel in pure water of four DEG C; ; immersing the prepared template into colloid and crystal solution, lifting and pulling the templateby a lifting-pulling machine, facilitating the formation of self-assembled colloid and crystal foil and waiting for the foil dried under ambient temperature, and softly making a hydrogel template with patterns formed in the second step contact with a substrate of hydrophobic material of the coating layer with colloid and crystal, removing the template, and an orderly colloid and crystal being transferred to the surface of the substrate.

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Method for printing micro contact pattern with hydrogel as template and colloid crystal as writing ink

Fabrication of nano-gold islands with μm spacing using 2.5 dimensional PDMS stamps

Abstract

Gold islands with diameters in the range of several tens of nanometers with μm spacing may act as binding sites for adapter molecules used for single molecule detection using optical fluorescence readout. Microcontact printing (μCP) using PDMS stamps and alkanethiol chemistry is a straightforward method for the structuring of gold layers. When using binary two dimensional (2D) stamps the softness of the elastomer limits the useable aspect ratio and it was shown that nm-sized features with μm spacing cannot be replicated with binary PDMS stamps. To bypass this limitation we used 2.5 dimensional PDMS stamps with pyramidal shaped topography to fabricate sub-100 nm gold islands with a spacing of 6 μm on areas of several square millimeters. The masters, the stamps and the resulting gold structures were analyzed using scanning electron microscopy (SEM).

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Fabrication of nano-gold islands with μm spacing using 2.5 dimensional PDMS stamps

Impression de Biomolécules par Lithographie douce, applications pour les Biopuces, de l’échelle Micrométrique à Nanométrique

Abstract

The main purpose of this research work is the demonstration that soft-lithography, very often called Micro-Contact Printing (μCP) is an efficient patterning technique for arranging biomolecules on a surface in the perspective of biochip applications. For DNA Micro-arrays applications, we demonstrate that μCP is a competitive method compared to the conventional spotting technology, commonly used today. The cost of the technology is much lower, the surface density of the chip is drastically increased and the quality and definition of the biopatterns are greatly improved. A systematic study of the inking mechanisms of the elastomeric stamps is provided together with the study and comprehension of transfer mechanisms of molecules from the surface of the stamp to the substrate. The crucial role played by the free fragments of polymers not cross-linked during the polymerisation of the stamp is highlighted. In a second section we investigate the possibility of using μCP for generating single biomolecule biochips. We show how this printing technique can be optimized for reaching sub-micrometric scale down to 50 nanometers features. A technological process involving soft-lithography is proposed: combing long DNA molecules on spatially organized and registered positions for genetic applications.

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Impression de Biomolécules par Lithographie douce, applications pour les Biopuces, de l’échelle Micrométrique à Nanométrique

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