Optimizing Multi-Well Micro-Electrode Array (MW-MEA) Design to Study the Electrophysiology of Neurons
Syed, Naweed I.
AuthorPishgar, Roofia Sara
Committee MemberTeskey, G. Campbell
Dunn, Jeff F.
Engineering--Electronics and Electrical
SubjectMicroelectrode arrays (MEAs), in-vitro electrophysiology, extracellular recording, signal to noise ratio (SNR), multi-well MEAs (MW-MEAs), brain cell activity
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AbstractMicroelectrode arrays (MEAs) have been widely utilized to measure and study neuronal activities, both in vitro and in vivo. The main focus of this study was to optimize the MEA design to improve the recording efficiency from a group of cells in an area to have a better understanding of what is happening over a larger network. This study included three phases: investigating the effectiveness of a preliminary version of multi-well MEA design with two electrode types featuring a different number of wells (5 and 6) and diameter of wells (15 and 20 μm); 2) optimization of the first design with the second version of multi-well MEA, featuring a wider range of diameters and number of wells on each electrode; 3) investigating the adaptability of rigid glass-based MW-MEAs to flexible substrates. The results of this study showed that electrodes with 6-wells had the ability to capture stronger signals occasionally, while electrodes with 5-wells could consistently record signals, albeit with less peak-to-peak amplitudes. It was found out that the effect of diameter and number of wells and their correlation (i.e., the open surface area of the electrode, A) on the signal to noise ratio (SNR) were significant and thus should all be regarded as important parameters when designing MEAs. Cell signal recording was performed on the second MEA design, using snail brain neurons. Snail brain neurons were used to limit the complexity of neuronal recordings and to be able to focus the analysis on the electrode characteristics. However, due to the COVID-19 related shutdown, the snail recording could not be pursued further in the lab. The study on the suitability of using flexible substrates instead of the traditional rigid glass substrate to make a flexible MEA (fMEA) showed oxidation, electrode degradation, and formation of residues in long-term mice cell plating. It indicated the incompatibility of the materials used with living cells. In parallel, a gold wire bonding process was attempted to create 3D microelectrodes on the fMEA. 3D-fMEA fabrication proved to be challenging due to several difficulties in the wire bonding process, used for converting the planar fMEA to 3D-fMEA. Thus, to further the study on the effectiveness of fMEA and 3D-fMEA, the choice of material and fabrication protocol of fMEA and 3D-fMEA needs further investigation.
CitationPishgar, R. S. (2020). Optimizing Multi-Well Micro-Electrode Array (MW-MEA) Design to Study the Electrophysiology of Neurons (Unpublished master's thesis). University of Calgary, Calgary, AB.
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