Objectives

The NucAN consortium develops a nanometer scale toolbox to create "smart materials" based on the use of natural and artificial nucleic acids. Nanometer sized particles and single (bio)molecules are connected to each other as well as to surfaces with well defined placing. Basic building blocks are being developed that can be arranged to well defined structures by self organisation, facilitated by molecular recognition. In the following such nucleic acid based nanostructures will be called "Nabnanos". The fields of application are bioanalytics, pharmaceutical receptor screening and nanoelectronics.

Besides the information content and their dominant role in all life sciences, especially genetics, nucleic acids have unique properties as polymers and as macromolecules. The addressability of each unique site within a given sequence on a nucleic acid strand by base recognition as well as the chemical homogeneity of the polymer through the repeating unit of the backbone makes nucleic acids ideal molecules for the construction of highly ordered supramolecular entities.

The objective is to achieve materials and systems with predictable composition and structure, and control of their final properties, here exclusively by variation of internal parameters. The interdisciplinary research includes growth, characterisation and functionalisation of nano-entities and their positional assembly. The positional assembly is guided by the base pairing recognition of nucleic acids and is investigated with regard to the relational position of the Nabnanos (topological order) as well as with regard to absolute positioning on surfaces (geometrical order).

The "smart material" approach addresses one of the central problems of general application of nanosciences and nanotechnology: the interfacing problem. The building blocks address this problem by self assembly that is directed through rational design of the connecting parts. The aim of the project will be reached by the following two lines: - Chemical construction of basic building blocks of DNA and PNA and link to peptides and proteins and to nanosized inorganic particles and nanotubes. - Surface contacting of those constructs.

The project is structured in two parts: the synthesis, construction and technology needed to facilitate the directed self assembling, and, secondly, the investigation of the applicability of the Nabnanos with respect to 1. nano-electronics, 2. bioanalytics and 3. pharmaceutical research.

1. In the field of nano-electronics we will focus on the single electron transistor (SET), that has been investigated recently by many groups focusing on its physical background. Here our (bio-) chemical approach may lead to an alternative way to facilitate formation of SET-structures thus opening the perspective for a cost effective production method, as well as an opportunity to direct several different devices in one single step.

2. In bioanalytics the manipulation and positioning through surface bound nucleic acids of single bio-macromolecules like enzymes and receptors is of great interest not only for basic research, but also for a variety of applications including diagnostics and bioelectronics. The manipulation of single molecules, here within a framework of self assembling entities, provides a new approach to the problem of electron-transfer from biomolecules (e.g. redox-enzymes) to semiconductors or electrodes, or within neighboured biomolecules. The same methods might be applied also to proton-transfer and transfer or transport of reactive groups or even signalling molecules.

3. In pharmaceutical research there is the problem of bi-ligand receptor screening. To construct libraries of bis-functional ligands and study their correlation addressable structures, the Nabnanos, are needed to achieve variability of the bi-lignads for screening. The perspective is to create a novel tool for drug screening in the pharmaceutical industry for an important, yet not well characterised class of drugs.