Carbon is an exciting material for bioelectrochemistry, due to a large potential window, chemical inertness and biocompatibility. We fabricate pyrolytic carbon microelectrode chips with various designs and electrode configurations, with the main objective to provide state-of-the art platforms for electrochemical monitoring of cell populations. The analytical methods include cyclic voltammetry (CV), amperometry and electrochemical impedance spectroscopy (EIS).
2D C4B chips with three-electrode configuration for CV and amperometry
The 2D C4B microelectrode chips have a circular working electrode (WE) and a counter electrode (CE) made of pyrolytic carbon obtained with the C-MEMS process from precursors such as SU-8 and AZ photoresist. Au pseudoreference electrode (RE) and contact leads are deposited by thermal evaporation through a shadow mask. An SU-8 passivation layer is deposited and patterned by photolithography. The pyrolysis process and the chip design have been optimized to decrease the resistivity of the pyrolytic carbon and improve the electrochemical performance in CV and amperometry.
2D C4B chips for impedance measurements
With electrochemical impedance spectroscopy (EIS) it is possible to monitor the attachment, spreading, growth and detachment of cells on an electrode. For this purpose it is advantageous to use either interdigitated microelectrodes or arrays of circular electrodes. We have recently demonstrated EIS measurements with real-time monitoring of HeLa cell cultures using circular carbon microelectrode arrays.
Left: 2D C4B electrode chips for impedance-based cell monitoring; Middle/right: HeLa cells grown on the electrodes result in increase of impedance
3D C4B chips for CV and amperometry
The fabrication of 3D carbon microstructures by pyrolysis of SU-8 precursor structures has been investigated. Integration of the 3D pyrolytic carbon microelectrodes as the working electrode of the C4B chips results in increased electrode surface area.This has been confirmed by increased peak currents in cyclic voltammograms obtained with standard redox probes such as ferri/ferrocyanide.
Left: 3D carbon microstructures on working electrode of microelectrode chip; Right: Cyclic voltammograms with 10 mM Ferri/ferrocyanide
Publications
- S. Hemanth, C. Caviglia, L. Amato, T.A. Anhøj, A. Heiskanen, J. Emnéus, S.S. Keller, ”Pyrolytic 3D carbon microelectrodes for electrochemistry”, Proceedings of Annual meeting of electrochemical society (ECS) (2016)
- Y.M. Hassan, C. Caviglia, S. Hemanth, D. Mackenzie, D.H. Petersen, S.S. Keller, “Pyrolytic carbon microelectrodes for impedance based cell sensing”, Proceedings of Annual meeting of electrochemical society (ECS) (2016)
Collaborators
Prof. Jenny Emnéus, Bioanalytics group, DTU Nanotech
Last updated 14.12.2016, Stephan Sylvest Keller