An Improved Transwell Design for Microelectrode Ion-Flux Measurements.

Boris Buchroithner,Sandra Mayr,Dmitry Sivun,Jaroslaw Jacak,Pavel Spurný,Johannes Heitz,Jost Ludwig

doi:10.3390/mi12030273

Abstract

The microelectrode ion flux estimation (MIFE) is a powerful, non-invasive electrophysiological method for cellular membrane transport studies. Usually, the MIFE measurements are performed in a tissue culture dish or directly with tissues (roots, parts of the plants, and cell tissues). Here, we present a transwell system that allows for MIFE measurements on a cell monolayer. We introduce a measurement window in the transwell insert membrane, which provides direct access for the cells to the media in the upper and lower compartment of the transwell system and allows direct cell-to-cell contact coculture. Three-dimensional multiphoton lithography (MPL) was used to construct a 3D grid structure for cell support in the measurement window. The optimal polymer grid constant was found for implementation in transwell MIFE measurements. We showed that human umbilical vein endothelial cells (HUVECs) efficiently grow and maintain their physiological response on top of the polymer structures.

Highlights

The transwell migration/invasion and the spreading assay are used to analyze the ability of single cells to directionally respond to chemoattractants and treatments and to test cell capacity to adhere to the extracellular matrix, respectively
The new design allows an investigation of physiological processes in direct cell-to-cell coculture, which could give deeper insight into cell–cell contact-dependent membrane transport processes and allow one to perform experiments in conditions closer to invivo
We showed that human umbilical vein endothelial cells (HUVECs) efficiently grow and keep their functional physiological response on 2D polymer grids

Summary

Introduction

The transwell migration/invasion and the spreading assay are used to analyze the ability of single cells to directionally respond to chemoattractants and treatments and to test cell capacity to adhere to the extracellular matrix, respectively. The classic transwell migration detection system uses a hollow plastic chamber sealed at one side with a porous membrane. This chamber is suspended over a larger well, which contains medium and/or chemoattractants. The assay was used to analyze the invasive abilities of tumor cells [3] and for detection and enumeration of circulating tumor cells based on their invasive property [4]. Most of these studies have used optical (i.e., fluorescence) methods

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Conclusion