Micro-Molded Glassy Carbon Electrodes for High Throughput Dielectrophoresis

3D glassy carbon electrodes employed in dielectrophoresis (DEP) devices provide the advantages of simple and affordable fabrication, functionality at low voltage and the wider electrochemical stability of carbon in comparison to traditional metal electrodes [1]. Furthermore, the use of 3D electrodes...

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Veröffentlicht in:Meeting abstracts (Electrochemical Society) 2018-04, Vol.MA2018-01 (13), p.1031-1031
Hauptverfasser: Muhamed, Sam Azhar, Natu, Rucha, Keck, Devin Monroe, Islam, Monsur, Martinez-Duarte, Rodrigo
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Sprache:eng
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Zusammenfassung:3D glassy carbon electrodes employed in dielectrophoresis (DEP) devices provide the advantages of simple and affordable fabrication, functionality at low voltage and the wider electrochemical stability of carbon in comparison to traditional metal electrodes [1]. Furthermore, the use of 3D electrodes offers high throughput of separation [2]. The state-of-the-art in the fabrication of glassy carbon micro- and nano-structures revolves around patterning and subsequent pyrolysis of organic precursors. In our previous work, we developed a computational model for high throughput sorting of stem cells using DEP [3]. Electrode dimensions in the range of hundreds of microns need to be fabricated to achieve practical throughput without compromising the cells by inducing increased shear stress. However, such dimensions are beyond the traditional operating range of SU-8 photolithography, making their fabrication challenging. On the other hand, precision machining techniques are still too bulky to enable easy and inexpensive fabrication in this scale. Here we propose the combination of 3D printed structures and Polydimethylsiloxane (PDMS) molds to shape an epoxy-based carbon precursor. The work presented here focuses on the development of reproducible carbon electrodes for application in high throughput dielectrophoretic separation. A 3D printed “inverse” mold containing an array of 1200 microns diameter cylindrical posts is fabricated to suit PDMS molding, which, in turn, is used to mold the carbon posts. Commercial grade PDMS mixed in the ratio of 10:1 was used to create molds of cylindrical posts using the standard procedure. The resulting PDMS molds ensured sufficient flexibility to facilitate easy removal of hardened materials. Plant-based epoxy, chitin, cellulose and carrageenan were tested in different mixtures as carbon precursors. Powdered chitin, cellulose and carrageenan were separately mixed into the epoxy at various ratios and introduced into the PDMS mold. Upon setting, they were removed from mold and pyrolyzed at 900 o C in an inert atmosphere to yield conductive carbon. Initial results showed how bio-epoxy, which consists of a 2:1 ratio of resin to hardener, fails to retain the shape of the mold through the pyrolysis process. On the other hand, chitin, cellulose and carrageenan when formed into gel and pyrolyzed retain shape, but yield fragile structures. Hence, we combined the binding capacity of bio-epoxy with the structural integrity provided by biopo
ISSN:2151-2043
2151-2035
DOI:10.1149/MA2018-01/13/1031