The iNAPO Project: Biomimetic Nanopores for a New Generation of Lab-on-Chip Micro Sensors

In nature, ion conducting nanopores play a vital role for the function of living cells. They undergo gating processes where they open and close upon an external stimulus, such as the presence of a particular biomolecule, the ligand. When the gating process is observed and is quantitatively measured one can derive data about the presence and the amount of the ligand. Hence, the nanopores can be utilized for specific sensing. However, biological nanopores are embedded in a biological cell membrane that is fragile and unstable with respect to storage and application. The iNAPO project aims at combining robust polymer-based nanopores with protein-based biological nanopores, thus combining the selectivity and sensitivity of the latter with the stability and processability of the first ones. This paper describes the different steps in the fabrication of ion conducting nanopores. It begins with ion irradiation of polymer foils, combined with chemical etching of the ion damage tracks into nanopores. By means of chemical coupling reactions, the nanopore walls are functionalized with particular molecules which react or bioconjugate with the molecules to be analyzed. As an example, a recent result on sensing a physiologically active P-based anion is shown. By means of a complexation reaction with Zn-di(picolyl)amine, the selective measurement of the concentration of the anion pyrophosphate is demonstrated. In the final step of the project, the nanopores will be incorporated into a Lab-on-Chip system for applications in e.g. medical diagnostics and environmental analysis.