Towards Molecular Nanotechnology



 

 

*    Overview

 

Our awarded research project “Towards molecular nanotechnology : individual molecules and templates” is presented on this page.

You can also find information on

Nanoscience and technology in Flanders

The Strategische TechnologieŽn voor Welzijn en Welvaart (STWW) – initiative coordinated by the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT).

 

Moreover there are brief descriptions of the research topics, organized in different work packages:

The detection and manipulation of individual molecules

The design of functionalized surfaces

Measurements on devices consisting of individual clusters and nanoparticles

The development of arrays for biochemical analysis


*    Nanoscience and technology in Flanders

 

All over the world nanoscience and -technology are getting top research priorities.  Also in Flanders, the government recognized the importance of this evolution and is stimulating the development of knowledge centers to acquire or maintain a level of competence on at least a European level.  Presently, nanoscience and -technology is in Flanders at an initial stage and has by a small number of laboratories been developed in open competition with other research topics within various disciplines. This is one of the reasons that the research efforts in nanotechnology are relatively fragmented and partially overlapping among disciplines, areas of relevance, and sources of funding.  This situation has advantages in establishing competitive paths in the emerging nanotechnology field and in promoting innovative ideas, and some disadvantages in developing practical, system applications. To improve on the current situation, four science Centers-of-Excellence in different domains at the K.U.Leuven and a selection of industrial partners are proposing this project which will enhance communication and fuel further linkages.

In order to be able to quickly incorporate new fundamental and technical ‘nanoknowledge’ into future technologies in Flanders, it is absolutely vital that new generations of specialists are trained and that the research activities become more and more multidisciplinary and interdisciplinary. We are convinced that this proposal will lay the foundations for the successful development of a nanotechnology-pole in Flanders.

 

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*    The Strategische TechnologieŽn voor Welzijn en Welvaart (STWW) - initiative

 

This project is partly sponsored by the Strategische TechnologieŽn voor Welzijn en Welvaart (STWW) – initiative.  Via this program, the Flemish government is funding basic research in strategic technologies inspired by the needs of the society and economy.  Research proposals are selected on a value-for-money base but possible applications can presently be generic in nature and only realistic at a long term.  The program encourages the development of interdisciplinary collaborations efforts amongst research units of different research institutes.  It strives to find an optimal equilibrium between the protection and distribution of knowledge, thereby focusing to maximize the economical return to Flanders.  The STWW-initiative emphasizes the explotation of new knowledge outside the academic circuit.  Therefore, industrial partners are actively participating in STWW funded research projects, as members of a User’s Commission.

More information is available from the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT) that is responsible for the coordination of the STWW-initiative.

 

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*    Towards molecular nanotechnology : individual molecules and templates

 

In this STWW-project we will concentrate our efforts on two main topics:

       Molecular nanotechnology:

This concerns the bottom-up synthesis of nanostructures with precise three-dimensional positional control of individual atoms and molecules.  The synthesis can be of chemical, biological or mechanical nature.  Chemical synthesis involves some form of self-assembly; biological concepts and mechanisms can be adapted into materials technology in various ways; three-dimensional nanostructuring can also be fabricated mechanically using scanning probes.

       Nanoscale-resolution microscopes:

These instruments form a new class of tools for imaging of the ultrasmall with a resolution below 100 nm.  For the study of individual molecules, self-assembled structures, clusters or nanoparticles we will use scanning probe microscopy (STM, AFM) and nanoscale-resolution-optical microscopy (SNOM).

The main goals of this STWW project can be summarized in different work packages (WP).  The first two work packages are fundamentally oriented.  They serve as a source of knowledge and experience to tackle more applied problems concentrated in the last two work packages.

       Detection and manipulation of individual molecules

The full range of scanning probe techniques, including STM, AFM, and SNOM will be used to probe interactions with submicrometer spatial resolution but also to modify structures on well defined surfaces.  The fundamental photophysical properties of conjugated polymers and corresponding oligomers investigated at the level of a single molecule allows to separate the intramolecular or single chromophore properties from intermolecular interchromophore interactions or interactions between polymers.  Such molecules are promising to be used in electroluminescent devices, transistors and energy convertors.

AFM technology is widely used to study the interaction force between biomolecules, e.g., two DNA molecules, an antibody and an antigen, a ligand and its receptor.  This involves the measurement of forces at the piconewton level with enough sensitivity to detect single bonds.  We propose to use a functionalized single wall carbon nanotube (SWNT) as a very sharp and well defined AFM tip.  The small diameter of the tip enhances greatly the possibility during an experiment since only one analyte molecule will bind with a single molecule at the SWNT.  This allows to perform experiments on more densely covered surfaces on which it is easy to locate and probe individual molecules.  In combination with simplified detection schemes, such a nanomanipulator can be used to develop, e.g., extremely sensitive biosensors suitable to be used outside a laboratory environment.

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       The development of designer surfaces

Patterning and control of the alignment and orientation of molecules are crucial for the development of molecular electronic devices, as well as for biomolecules or functional single molecules on specific surfaces. Various kinds of methods to create nano- or micro-level two-dimensional arrays on the surfaces have been studied and reviewed.  Among these techniques, self-assembly in combination with contact printing are widely accepted as the best suited candidate methods to control the pattern and alignments of molecules on a surface. Both techniques are based on the chemical interaction between the molecules and surfaces and can easily and efficiently form a nanoscale system.  The functionality of the patterned surface obtained with contact printing techniques is directly related to the chemical properties of the terminating groups of the molecules.  They determine the applicability of the patterned monolayer.

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       Measurements on devices consisting of individual clusters and nanoparticles

The operation of  future generations of nano-electronic devices will be largely based on quantum mechanical phenomena such as tunneling effects, confinement and phase coherence.  A thorough understanding of the intrinsic quantum physical character of nanosystems is thus of utmost importance.  The characterization and controlled modification of the structural, electromagnetic and optical quantum properties of well defined nanosystems, including single-walled carbon nanotubes, deposited clusters and II-IV-semiconductor nanoparticles will be pursued.  Carbon nanotubes exhibit unique physical properties, both structural and electronic, that are relevant to a broad range of potential applications.  Within the framework of this work package, the fundamental electronic transport properties of carbon nanotubes with different chirality, doping and lattice defects will be studied using scanning tunnelling spectroscopy in combination with conductance measurements.  Also the field-emission properties of carbon nanotubes deposited on patterned substrates will be investigated.

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       The development of arrays for biochemical analysis

DNA arrays revolutionized the collection and analysis of genetic information.  In this strongly application-oriented work package downsizing the dimensions of such a DNA lab-on-a-chip is targeted.  Presently, DNA microarrays are prepared by distributing known snippets of DNA to precisely known positions on a substrate.  State-of-the-art photolithography techniques produce arrays on which each element containing probe sequences occupies a spot of 8 x 8 mm2.  To reduce the dimensions of an element below 1 mm, different strategies both in the production as well as in the final read-out of such a nanoarray will be pursued.

To develop a nanoarray, a large number of problems on linker-chemistry have to be investigated in detail.  These include the characterization of the electronic and the electrochemical properties of DNA, and the development of linkers to attach DNA to a substrate.  The effect of the density of the DNA-linkers on the hybridization will be determined by spotting DNA solutions with different concentrations and determine the final densities by AFM techniques.  The implications of the use of specific linker molecules on the addressability of DNA strands in the sample, and thus on the hybridization, can be evaluated using similar methods.  The development of specialized linker chemistry to attach nanomarkers such as magnetic clusters containing only a few thousand atoms each, will be initiated.  Photolithographic techniques using light sources eliminate the use of masks in the production process.

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Copyright ©2000 Katholieke Universiteit Leuven
Comments for the authors: Erno Vandeweert
Realisation: Erno Vandeweert
Last revision:  November 02, 2000

URL: http://www.fys.kuleuven.ac.be/vsm/ini/project.htm