Abstract
Microelectrode arrays (MEAs) are widely used platforms in bioelectronics to study electrogenic cells. In recent years, the processing of conductive polymers for the fabrication of three-dimensional electrode arrays has gained increasing interest for the development of novel sensor designs. Here, additive manufacturing techniques are promising tools for the production of MEAs with three-dimensional electrodes. In this work, a facile additive manufacturing process for the fabrication of MEAs that feature needle-like electrode tips - so called µ-needles - is presented. To this end, an aerosol-jet compatible PEDOT:PSS and multi-walled carbon nanotube composite ink with a conductivity of 323±75 S m is developed and used in a combined inkjet and aerosol-jet printing process to produce the µ-needle electrode features. The µ-needles are fabricated with a diameter of 10±2 µm and a height of 33±4 µm. They penetrate an inkjet-printed dielectric layer to a height of 12±3 µm. After successful printing, the electrochemical properties of the devices are assessed via cyclic voltammetry and impedance spectroscopy. The µ-needles show a capacitance of 242±70 nF at a scan rate of 5 mV s and an impedance of 128±22 kΩ at 1 kHz frequency. The stability of the µ-needle MEAs in aqueous electrolyte is demonstrated and the devices are used to record extracellular signals from cardiomyocyte-like HL-1 cells. This proof-of-principle experiment shows the µ-needle MEAs' cell-culture compatibility and functional integrity to investigate electrophysiological signals from living cells.
Citation
ID:
12560
Ref Key:
zips2019fullyacs