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.

The present paper describes the fabrication sequence of a LIGA mold insert by electroforming after the patterning steps of the overall process. These tools are applied for large scale fabrication of microcomponents made by molding and embossing processes. The application of an intermediate layer system leads to optimized process performance and to a better surface quality of the mold insert. The plating processes are described and the materials properties, e.g. hardness, are used for the characterization of the recrystallization behavior of the electroformed nickel which yields the high temperature application limit of the tool.

Repeated photolithographic and etching processes allow the production of multileveled polymer microstructures that can be used as templates to produce bacterial cellulose with defined surfaces on demand. By applying this approach, the bacterial cellulose surface obtains new properties and its use for culturing neural stem cells cellulose substrate topography influences the cell growth in a defined manner.

Since the advent of biosensing, structuring of electrode surfaces for the improvement of cell-coupling and electrophysiological properties has been extensively investigated. Most of these methods result in structures with predefined dimensions and regular organization. Nevertheless, natural adhesion surfaces of the cells are hardly uniform. Therefore, this study focusses on fabricating randomly organized nanostructures mimicking the irregular distribution of natural collagen fibers coated on a planar surface. Fiber geometries are replicated by using a spincoating process followed by thermal nanoimprint lithography and gold electroplating. Microscopic studies reveal the width of these biomimetic collagen-like gold nanostructures ranging between 200 nm and 5 µm, with a uniform height of ≈35 nm. In comparison to unstructured gold surfaces, nanostructured surfaces display a decrease in impedance magnitude by 50% for frequencies below 1 kHz and show an increase in critical free surface energy by 35%, the latter translating to an increased surface wettability. Culturing enteric neurons from postnatal mice, a relative hard to handle type of neurons, results in an improved spreading of the neural networks on the nanostructured surfaces.

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Microbial cellulose paper treated with polyaniline and carbon nanotubes (PANI/CNTs) can be attractive as potential flexible capacitors in terms of further improvements to the conductivity and thermal resistance. The interactions between PANI and CNTs exhibit new electrochemical features with increased electrical conductivity and enhanced capacity. In this study, PANI/CNTs was incorporated into a flexible poly­(4-vinylaniline)-grafted bacterial cellulose (BC/PVAN) nanocomposite substrate for further functionalization and processability. PANI/CNTs coatings with a nanorod-like structure can promote an efficient ion diffusion and charge transfer, with a significant enhancement of the electrical conductivity after CNTs reinforcement of 1 order of magnitude up to (1.0 ± 0.3) × 10–1 S·cm–1. An escalating improvement of the double charge capacity (∼54 mF) of the grafted BC nanocomposites was also detected through electrochemical analysis. The multilayered electrical coatings also reinforce the thermal resistance, preventing anticipated thermal degradation of the BC substrate. The cell viability and differentiation assays using neural stem cells (SVZ cells) testified to the cytocompatibility of the grafted BC nanocomposites, while inducing neuronal differentiation over 7 days of culture with a neurite that was 77 ± 24.7 μm long. This is promising for meeting the requirements in the construction of high-performance bioelectronic devices that can actively interface biologically, providing a friendly environment for cells while tuning the device performance.

Tip-enhanced Raman spectroscopy (TERS) is an emerging technique with a large number of potential applications in different fields such as chemistry, physics, biology, life sciences, and materials science. TERS in liquids offers nondestructive and label-free topographical and chemical imaging of molecules and chemical reactions under native conditions at a nanometer scale. It combines Raman spectroscopy with scanning probe microscopy, providing a unique combination of chemical information and high spatial resolution. The versatility of TERS increases even further if it is modified for simultaneous electrochemical measurements. This paper reviews the recent progress of TERS in liquid, with a focus on molecular structures, interfaces, and chemical reactions studied to date. For example, TERS studies revealed nanoscale chemical images of various molecules containing a benzene ring such as thiophenol or carbon nanotubes. Additionally, heterogeneous catalytic reactions at the solid−liquid interface were investigated in a new way to gain a deeper insight into electrochemical processes. Furthermore, TERS measurements expanded our knowledge of several redox compounds and enabled new insights into various chemical transformations. Despite substantial progress, TERS in liquids is not yet a routine measurement method, and there are still several challenges to solve before TERS can unleash its full potential.