Paper Abstract

Monitoring electrical activity across multiple planes in 3D cell cultures and organoids is imperative to comprehensively understand their functional connections and behavior. However, traditional planar microelectrode arrays (MEAs) are intended for surface recordings and are inadequate in addressing this aspect. The limitations, such as longer production times and limited adaptability imposed by standard clean-room techniques, constrain the design possibilities for 3D electrode arrays and potentially hinder effective cell-electrode coupling. To tackle this challenge, a novel approach is presented that leverages rapid prototyping processes and additive manufacturing in combination with wet etching and electrodeposition to enhance electrode fabrication and performance. The laser-patterned MEAs on glass, polyimide (PI) foil, or polyethylene terephthalate (PET) foil substrates incorporate high-aspect ratio (up to 44:1) ink-jet printed 3D electrode structures with heights up to 1 mm at a pitch of 200 µm, enabling precise recording within cell tissues. The specific shapes of the electrode tips and customizable 3D structures provide great flexibility in electrode placement. The versatility of the 3D MEAs is demonstrated by recording the electrophysiological activity of cortical organoids in situ, paving the way for investigating neural activity under regular or various pathologically altered conditions in vitro in a high throughput manner.

This is required for common thin-film evaporants so that they are vapourised from a source. The evaporants then move up through a process chamber to condense on a substrate. Higher source temperatures allow for the deposition of materials with higher evaporation/sublimation temperatures.

How Moorfield products helped:

Our benchtop nanoPVD-S10A thin film deposition system was used to deposit a layer stack of 25 nm Ti and 200 nm of Au (5 × 10-3 mbar argon, 12 W Au, 40 W Ti) on the glass slides using DC magnetron PVD sputtering.
 

Image Caption: Fabrication 3D MEAs. A) Schematic fabrication approach for creating pillar arrays with different heights and tip shapes on a planar MEA. B) Illustration of the various layers of a 3D MEA.

Open Access publication details:

Kopic, I. et al. (no date) ‘Inkjet-Printed 3D Electrode Arrays for Recording Signals from Cortical Organoids’, Advanced Materials Technologies, n/a(n/a), p. 2400645. Available at: https://doi.org/10.1002/admt.202400645.