Fabrication Of 3D Nanostructured Multielectrode Arrays By Using Thermal Nanoimprint Lithography To Improve Cell Coupling For Low Signaling Neurons
-
1
University of Applied Sciences Kaiserslautern, Department of Informatics and Microsystems Technologie, Germany
Motivation
Recently a lot of effort was done in optimizing MEA technology in order to enhance signal qualities and to improve the coupling with cells in a culture. Recording performances can be improved by either coating the MEA with artificial or biological polymers or by adding three dimensional nanostructures on top of the sensing pad, thus increasing the surface area and ensuring a tight cell electrode coupling by partly engulfing the nanosized MEA features by the cells [1, 2]. Here we present a fabrication process of nanostructured MEA chips based on nanoimprint lithography (NIL) and electroplating. Compared to other nanostructuring techniques, NIL offers the possibility to fabricate a whole set of nanostructures on several chips at the same time in a fast, simple and inexpensive full wafer process. The nanostructured MEA devices will later be used for action potential measurements and drug testing with neurons with relative weak signals, such as those from the enteric nervous system.
Materials and Methods
Silicon or glass wafers are vapor-deposited with 20 nm titanium and 200 nm gold layers, followed by a 200 nm thin spin-coated layer of a thermal resist. Nanoimprint lithography is performed (figure 1) with a customized silicon master stamp including a broad range of nanostructures with different geometries, diameters and arrangements. After removing the residual layer with reactive ion etching the nanostructures are filled with gold by electroplating. Microfabrication techniques including photolithography, wet chemical etching and chemical vapor deposition steps are needed to define the leads, the sensing areas and the contact pads of the MEA chips. Subsequently the wafer is cut. The separated chips are bonded to a PCB, encapsulated and prepared for cell culture experiments.
Results and Discussion
Different nanostructures like meanders, lines, pillars and tubes with diameters from 50 nm up to 800 nm, different heights up to 500 nm and variable distances between the structures have successfully been fabricated on gold-coated substrates. By means of overelectroplating it is also possible to create mushroom-like or muffin-like structures. AFM and SEM pictures show a good structure transfer during NIL and a high uniformity of the electroplated nanostructures over the whole wafer (figure 2). Electrochemical characterization of the fabricated structures is done with cyclic voltammetry and electrochemical impedance spectroscopy. As expected the measurements show an increase of the electrochemical active surface area and a reduction of the impedance compared to planar electrodes. First biocompatibility tests with P19 cells also show a good cell electrode coupling.
Conclusion
The presented fabrication process incorporates an alternative, high throughput, time saving and thus cost-efficient method for the integration of nanostructures on MEA chips. Different nanostructures are investigated to find an ideal combination of shape, dimension and arrangement for enhancing the signal-to-noise ratio. Future work will be based on recordings with living cells where we intend to work with neurons from the enteric nervous system. These experiments will explore which nanostructures are best suited for cell electrode coupling and thus signal detection from this particular cell type.
References
[1] D. Brüggemann, B. Wolfrum, V. Maybeck, Y. Mourzina, M. Jansen and A. Offenhäuser, “Nanostructured gold microelectrodes for extracellular recording from electrogenic cells”, Nanotechnology, IOP Publishing, Jülich, 2011, pp. 1-7.
[2] A. Fendyur, N. Mazurski, J. Shappir and M. E. Spira, “Formation of essential ultrastructural interface between cultured hippocampal cells and gold mushroom-shaped MEA - toward “IN-CELL” recordings from vertebrate neurons”, Frontiers in Neuroengineering, published online: www.frontiersin.org, Jerusalem, 2011, pp.1-14.
Figure Legend
Figure 1: Schematic drawing of the thermal NIL process step. A master stamp including the nanostructures is pressed into a resist on top of the substrate (left). After increasing the temperature above the glass temperature of the resist a pressure of several tens of bar is applied (middle). After a few miniutes the temperature is reduced and the stamp is detached (right).
Figure 2: SEM picture of 500 nm muffin-like structures (left) and cross-section of 800 nm mushroom-like structure (right) on gold-coated substrates manufuctured by NIL and gold electroplating.
Acknowledgements
The authors would like to thank Stiftung Rheinland-Pfalz für Innovation for funding the project.
Keywords:
Electroplating,
Nanostructures,
Neurons,
multielectrode array,
nanoimprint lithography,
drug tests,
carcinoma cells
Conference:
MEA Meeting 2016 |
10th International Meeting on Substrate-Integrated Electrode Arrays, Reutlingen, Germany, 28 Jun - 1 Jul, 2016.
Presentation Type:
Poster Presentation
Topic:
MEA Meeting 2016
Citation:
Decker
D,
Ingebrandt
S,
Rabe
H,
Schäfer
K and
Saumer
M
(2016). Fabrication Of 3D Nanostructured Multielectrode Arrays By Using Thermal Nanoimprint Lithography To Improve Cell Coupling For Low Signaling Neurons.
Front. Neurosci.
Conference Abstract:
MEA Meeting 2016 |
10th International Meeting on Substrate-Integrated Electrode Arrays.
doi: 10.3389/conf.fnins.2016.93.00039
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
22 Jun 2016;
Published Online:
24 Jun 2016.
*
Correspondence:
Dr. Dominique Decker, University of Applied Sciences Kaiserslautern, Department of Informatics and Microsystems Technologie, Zweibrücken, Germany, dominique.decker@hs-kl.de