Nanoscience and Molecular Nanotechnology

Biography

Biography: Wolfgang Ensinger

Abstract

The iNAPO-project is run by a group of materials scientists, biologists, chemists, physicist and electrical engineers. One of the main purposes is the development of biomimetic (bio)molecular sensors based on ion conducting nanopores in polymer foils. The basic principles of fabrication and working mechanism of such a nanosensor are described. PET foils are irradiated with a highly energetic single ion of a heavy element at the particle accelerator at GSI Helmholtz-Center in Darmstadt. The ion damage zone in the polymer is chemically etched into a conical pore, with the small aperture being in the nm range. The nanopore walls are functionalized with a biorecognition unit, i.e. a molecule which specifically reacts with a molecule to be analysed. In an electrochemical cell, the foil acts as separation membrane. The electrolyte current flowing through it is measured as a function of the applied potential. In the presence of specific analyte molecules, which bioconjugate with the biorecognition unit, these ionic currents are changed. Thus, a highly sensitive nanosensor is available. The preparation and working principle of the nanosensor is described. As an example, results on protein sensing are shown. In Fig. 1, the quantitative measurement of the protein Concanavalin A that specifically bioconjugates with mannose is depicted. The concept of the functionalized ion conducting nanopores can be applied to a large number of biorecognition couples. Within the project iNAPO, the potential of this technique will be further explored. In a step further, it is planned to embed protein-based nanopores with even better selectivity into polymer membranes. Eventually, the membranes will be incorporated in electronic micro sensing devices thus creating a new type of (bio)molecular sensor. The development is supported by analytical studies based on NMR and by theoretical and simulation studies.