Topographical imaging and charged mapping of charged samples using scanning ion conductance microscopy with a theta nanopipette

Abstract

A scanning ion conductance microscope (SICM) can image living samples in liquid by detecting ion current through a nanopipette. The nanopipette has an aperture of approximately 100 nm in diameter. In the SICM technique, it is difficult to obtain electrically charged samples because of the complicated ion current behaviors detected with the nanopipette in the vicinity of the surface. In this study, to observe charged samples, we used a theta type nanopipette as a probe of the SICM. Furthermore, we additionally developed a method for obtaining a charge map of the sample surface. By using the proposed method, a topographical image and a charge map of the chromosome were successfully obtained simultaneously.