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Abstract

The investigation of electric phenomena occurring in biological cells is the subject of electrophysiological research. The discovery of ionic currents as the origin of membrane resting- and action-potentials led to a comprehensive understanding of various essential biological processes, e.g. trans-membrane transport, signal transduction in the nervous system and muscle contraction. Throughout the 20th century numerous experimental methods for observation of these phenomena have been developed and continuously improved. Precise measurements of intracellular potentials using current- and voltage-clamp based methods have become standard laboratory practice. Despite their huge success, these methods suffer from their invasive nature and inherent workload. Therefore, new methods have been sought, leading to the development of flat microelectrodes, allowing long-term stable electrical measurements with live cells and tissue samples. Arrays of flat electrodes have enabled multi-site and multi-cell measurements, but with the drawback of poor signal amplitude and signal-to-noise ratio. The continuous improvement of nanofabrication methods has enabled the fabrication of vertical nanowires. Such structures have been intensively studied in the past two decades, aiming at the design novel platforms with highly improved electrical properties for intracellular measurements. In this work, fabrication methods for gold nanoelectrode-ensembles are studied in detail. Each step of the manufacturing process for the ensembles is reviewed in detail, resulting in more efficient manufacturing of electrodes with variable diameter and length as well as significantly improving the quality of the obtained samples. The manufactured structures were tested with electrochemical impedance spectroscopy and cyclic voltammetry to evaluate their performance for intracellular recording in in-vitro experiments with live cells.