Plasma etched carbon microelectrode arrays for bioelectrical measurements

Abstract

Carbon-based materials have attracted much attention in biological applications like interfacing electrodes with neurons and cell growth platforms due to their natural biocompatibility and tailorable material properties. Here we have fabricated sputtered carbon thin film electrodes for bioelectrical measurements. Reactive ion etching (RIE) recipes were optimized with Taguchi method to etch the close field unbalanced magnetron sputtered carbon thin film (nanocarbon, nC) consisting of nanoscale crystalline sp 2-domains in amorphous sp 3-bonded backbone. Plasma etching processes used gas mixtures of Ar/O 2 /SF 6 /CHF 3 for RIE and O 2 /SF 6 for ICP-RIE. The highest achieved etch rate for nanocarbon was 389 nm/min and best chromium etch mask selectivity was 135:1. Biocompatibility of the material was tested with rat neuronal cultures. Next, we fabricated multielectrode arrays (MEA) with carbon recording electrodes and metal wiring. Organotypic brain slices grown on the MEAs were viable and showed characteristic spontaneous electrical network activity. The results demonstrate that interactions with nanocarbon substrate support neuronal survival and maturation of functional neuronal networks. Thus the material can have wide applications in biomedical research.

High Performance Power Supplies for Plasma Materials Processing

“…Such a process therefore requires at least two power supplies: one for the plasma source where the ions and reactive radicals are formed, and another to negatively polarize (bias) the substrate to attract and accelerate ions to the surface being etched away. Because this technique makes it possible to etch structures of a very high aspect ratio (HAR), it is widely used in the semiconductor industry: from Through-Silicon Vias (TSV) manufacturing [21], through nanocarbon film etching [22], to GaN and Si surface treatment [23], [24].…”

Electrochemical biosensors based on in situ grown carbon nanotubes on gold microelectrode array fabricated on glass substrate for glucose determination

“…Microelectrode arrays (MEAs) have been used for correlating biological activities with electrical signals [ 7 ] and measuring the electrochemical response from biomolecules or organic analytes [ 8 ]. The MEA can be used to sense analytes present in a solution with the possibility of designing highly sensitive and reliable biosensors.…”

Fabrication of Micro- and Nanopillars from Pyrolytic Carbon and Tetrahedral Amorphous Carbon

“…Wet etching of carbon films is considered very challenging if not impossible as the internal carbon bonds are very strong. Different types of plasma etching processes are used with varying gas chemistries as the ion bombardment provides enough energy to break the carbon bonds and correct gas selection reacts with the resulting radicals [38]. Among the DLCs, the more sp 3 hybridized carbon films are more challenging to etch compared to sp 2 hybridized films.…”