Rheinlaender Johannes, Schäffer Tilman E
Institute of Applied Physics, University of Tübingen , Auf der Morgenstelle 10, 72076 Tübingen, Germany.
Anal Chem. 2017 Nov 7;89(21):11875-11880. doi: 10.1021/acs.analchem.7b03871. Epub 2017 Oct 27.
The scanning ion conductance microscope (SICM) is an emerging tool for noncontact topography imaging and multiphysical investigation of soft samples in aqueous environments such as living cells. Despite the increasing popularity of SICM, several aspects of the imaging process are still unknown; for example, there is still no accurate description of the behavior of the ion current for a varying tip-sample distance. To predict this ion current-distance behavior, we provide a new numerical model based on finite element modeling. The model allows, for the first time, accurately determining the tip-sample distance during an SICM experiment. Furthermore, we present a nondestructive method for calibrating the pipet tip geometry by fitting the numerical model to the experimental ion current-distance data and verify this method using pipets with opening radii between 30 and 300 nm.
扫描离子电导显微镜（SICM）是一种新兴工具，用于在诸如活细胞等水性环境中对软样品进行非接触式形貌成像和多物理场研究。尽管SICM越来越受欢迎，但成像过程的几个方面仍然未知；例如，对于变化的针尖-样品距离下的离子电流行为仍没有准确描述。为了预测这种离子电流-距离行为，我们基于有限元建模提供了一种新的数值模型。该模型首次能够在SICM实验期间准确确定针尖-样品距离。此外，我们提出了一种通过将数值模型拟合到实验离子电流-距离数据来校准移液管针尖几何形状的无损方法，并使用开口半径在30至300nm之间的移液管验证了该方法。
