Abstract
To electrically detect the nanoparticles such as pollen allergens or biomolecules by the use of gating nanopore technologies, the rapid change of ion current induced by the ion flow with the translocation of the charged particle should be precisely measured. From the direct or statistical evaluations of the current change, the identification of molecules, e.g., DNA bases, becomes to be practical. When the nanoparticles translocate through the nanopore, the ion current decreases because the particle prevents the path of ion flow between the electrodes, and it is well known as the principle of the Coulter counter. On the other hand, in some special cases of nanopore size and the molecular structures, it can be observed that the detected current increases during the translocation. It must be so-called the tunnel current which is from quantum mechanical effects. In this paper, the theoretical backgrounds of ion and tunnel currents detections, and the comparison with experimental results are introduced.
