FEM-based design of optical transparent indium tin oxide multielectrode arrays for multiparametric, high sensitive cell based assays

• Published in: Biosensors & bioelectronics Vol. 129; pp. 208 - 215
• Main Authors: Jahnke, Heinz-Georg, Schmidt, Sabine, Frank, Ronny, Weigel, Winnie, Prönnecke, Christoph, Robitzki, Andrea A.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2019
• Subjects: Cell-electrode equivalent circuit model; FEM simulated indium tin oxide electrodes; Multielectrode array optimization; Optical transparent indium tin oxide electrodes; FEM simulated indium tin oxide electrodes; Optical transparent indium tin oxide electrodes; Multielectrode array optimization; Cell-electrode equivalent circuit model
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2018.09.095

Multielectrode array (MEA) technology is widely used for the bioelectronic monitoring of cellular alterations. In general, noble metal based MEAs are preferred e.g. for impedance spectroscopy because of their high conductivity and biocompatibility. Today's research focuses on combining different readout methods in a single measurement setup, such as sensitive electronic and optical readouts, where noble metal-based electrodes are excluded and transparent electrodes and optimized MEAs are required. In this context, we used optical transparent indium tin oxide (ITO) as electrode material. As a drawback, the decreased conductivity can lead to drastically decreased cell signals and it is hardly to predict which layout changes lead to a substantial signal increase. To overcome this limitation, we introduce an approach where equivalent circuit modelling (ECM) on reference multielectrode arrays is used to determine cell type specific electrical parameters, which then are used in finite element method (FEM) simulations to predict achievable cell signals and signal-noise-ratios (SNR) and thus use simulation to efficiently optimize multielectrode arrays. To evaluate our approach, MEAs with a wide range of electrode sizes were fabricated with ITO and gold. HEK-A cells were used to compare achievable cell signals for impedimetric monitoring. Our study revealed that especially for large ITO electrodes, the sensitivity drastically decreases. To overcome this drawback, we designed an optimized dual layer ITO MEA with gold support structures and more strikingly, successfully predict the cell signal increase by using our combined ECM and FEM simulation based approach. •Impedimetric analysis of cell signal using transparent ITO electrodes arrays.•Drastic cell signal decrease with increased electrode size.•Equivalent circuit model analysis of electrical electrode-electrolyte and cell layer parameters.•FEM simulation derived impedance spectra correlates with measurement data.•Successful ITO IDE array optimization based on FEM simulation.