Development and Characterization of a Diamond-Insulated Graphitic Multi Electrode Array Realized with Ion Beam Lithography

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 ∼mΩ·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 (4.5 × 4.5 × 0.5 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.

All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmitters

“…1 . The first system consists of an array of variable-thickness copper masks directly deposited over the sample surface which modulate the penetration depth of the ions, thus ensuring the connection of the sub-superficial amorphized structures with the sample surface at their endpoints 22 23 24 . 32 square (20 × 20 μm 2 and 3 μm maximum thickness) metal depositions were defined to this scope.…”

Assessment of acid and thermal oxidation treatments for removing sp2 bonded carbon from the surface of boron doped diamond

“…In this way sp 2 bonded carbon microarray electrodes in diamond have been created for the detection of neurotransmitters. [39,40] Nonetheless, for many applications of diamond (and BDD) removal of any processing-created or growth related forms of sp 2 bonded carbon at the surface of the material is important. In this paper we first examine the effectiveness of two different oxidative treatments at removing surface sp 2 bonded carbon created during the ns-laser micromachining process.…”

Ion Microbeam Analysis in Cultural Heritage: application to lapis lazuli and ancient coins

“…Ion beam analyses were carried out mainly by means of two scanning proton micro-beam lines at INFN (National Institute for Nuclear Physics) facilities having different acceleration voltages: the 2.5 MV AN2000 accelerator at the Legnaro National Laboratory (INFN-LNL) in Padua (Figure 1) widely used for material characterization/modification and ion implantation [6]- [8] and the 3 MV accelerator of the INFN-LABEC Laboratory in Florence (Figure 2) widely used for multi-disciplinary studies [9]- [11]. In few cases also the in air AGLAE microbeam facility of the C2RMF in Paris was used [12].…”