Development and characterization of a diamond-insulated graphitic multi electrode array realized with ion beam lithography

TL;DR

This paper presents a novel diamond-based multi-electrode array fabricated via ion beam lithography, enabling sensitive detection of neurochemical exocytosis events with potential for advanced biosensing applications.

Contribution

The study introduces a new diamond-insulated graphitic multi-electrode array fabricated with ion beam lithography, demonstrating its suitability for biosensing in neuroscience.

Findings

Successfully fabricated a 16-channel diamond-based MEA with ion implantation.

Demonstrated the biosensor's sensitivity to adrenaline in vitro.

Confirmed potential for detecting catecholamine release in neural applications.

Abstract

The detection of quantal exocytic events from neurons and neuroendocrine cells is a challenging task in neuroscience. One of the most promising platforms for the development of a new generation of biosensors is diamond, due to its biocompatibility, transparency and chemical inertness. Moreover, the electrical properties of diamond can be turned from a perfect insulator into a conductive material (resistivity Ohm cm) by exploiting the metastable nature of this allotropic form of carbon. A 16 channels MEA (Multi Electrode Array) suitable for cell culture growing has been fabricated by means of ion implantation. A focused 1.2 MeV He+ beam was scanned on a IIa single-crystal diamond sample (4.5x4.5x0.5 mm3) to cause highly damaged sub-superficial structures that were defined with micrometric spatial resolution. After implantation, the sample was annealed. This process provides the conversion of the sub-superficial highly damaged regions to a graphitic phase embedded in a highly insulating diamond matrix. Thanks to a three-dimensional masking technique, the endpoints of the sub-superficial channels emerge in contact with the sample surface, therefore being available as sensing electrodes. Cyclic voltammetry and amperometry measurements of solutions with increasing concentrations of adrenaline were performed to characterize the biosensor sensitivity. The reported results demonstrate that this new type of biosensor is suitable for in vitro detection of catecholamine release.