3D Nanostructured Multielectrode Arrays: Fabrication, Electrochemical Characterization, and Evaluation of Cell–Electrode Adhesion

Abstract

Abstract3D nanostructures on top of planar multielectrode array (MEA) electrodes increase the surface area and can offer a tight and stable cell–electrode interface, thus leading to a crucial increase of the signal‐to‐noise ratio during measurement. However, each individual cell type might need specific dimensions and an arrangement of nanostructures that fits ideally to a specific cell type. Therefore, a fabrication method of 3D nanostructured MEA chips based on nanoimprint lithography, gold electroplating, and microstructuring techniques is presented which allows the fabrication of a whole set of MEA chips with different nanostructure layouts in one single approach. The chips are characterized using electrochemical methods, atomic force, and scanning electron microscopy. Furthermore, an impedance measurement method is presented to quantify cell–electrode adhesion of nanostructured and unstructured electrodes using the human embryonic kidney cell line (HEK 293). Double‐layer capacitance, transferred charge, and impedance values of different nanostructure layouts revealed a significant improvement compared to unstructured electrodes. The improvement strongly correlates with the increase of the electrochemical active surface area. Impedance measurement with impedance‐stable HEK 293 cells allows discriminating differences of cell adhesion between the individual nanostructure layouts. A significant increase or decrease of cell–electrode coupling depending on the nanostructure layout is demonstrated.

Biosensors for Studies on Adhesion-Mediated Cellular Responses to Their Microenvironment

“… Susloparova et al (2015) created new substrates for ECIS using open gate field-effect transistors instead of gold electrodes, which allowed to obtain single-cell resolution of the impedance measurements. Decker et al (2019) employed 3D nanostructured multielectrode arrays to study cell adhesion. Using nanoimprint lithography, the authors created an electrode with incorporated nanostructures in different forms, dimensions, or pitch lengths in a reproducible way.…”

Biomimetic Nanostructures Fabricated by Nanoimprint Lithography for Improved Cell‐Coupling

“…Apart from excellent resolution, another great feature of NIL is its reproducibility in fabrication of structures of different shapes, all organized in predefined structural geometry, dimensions and intra-structural distances. [26] In order to fabricate random nanostructures with NIL, the master stamp must have a random topographical pattern. The latter can be either achieved by designing a random pattern with computer algorithm and then developing it with engineering methods (e.g., e-beam lithography) or can be inspired from natural surfaces (e.g., nanostructure pattern on cicada moth wing).…”

“…In recent times, nanostructuring techniques have been in use to generate metal nanostructures with spatial resolution as small as 100 nm for bioanalytical applications. [ 23–26 ] Furthermore, electrophysiological studies with neuronal cultures have shown significant improvement in cell–surface coupling and in bioelectrical signal transduction induced by these nanostructures. [ 23–26 ] Although most of the traditional nanostructuring techniques result in fabrication of regularly organized structures, the natural substrates in living systems on which cells attach and grow have a rough and irregular surface.…”

“…[ 23–26 ] Furthermore, electrophysiological studies with neuronal cultures have shown significant improvement in cell–surface coupling and in bioelectrical signal transduction induced by these nanostructures. [ 23–26 ] Although most of the traditional nanostructuring techniques result in fabrication of regularly organized structures, the natural substrates in living systems on which cells attach and grow have a rough and irregular surface. [ 8,9,27 ] For instance, basement membranes (BM) are found throughout the vertebrae body and serve as a substrate for overlying cellular structures.…”

“…Apart from excellent resolution, another great feature of NIL is its reproducibility in fabrication of structures of different shapes, all organized in predefined structural geometry, dimensions and intra‐structural distances. [ 26 ]…”