Planar Diamond-Based Multiarrays to Monitor Neurotransmitter Release and Action Potential Firing: New Perspectives in Cellular Neuroscience

Abstract

High biocompatibility, outstanding electrochemical responsiveness, inertness, and transparency make diamond-based multiarrays (DBMs) first-rate biosensors for in vitro detection of electrochemical and electrical signals from excitable cells together, with potential for in vivo applications as neural interfaces and prostheses. Here, we will review the electrochemical and physical properties of various DBMs and how these devices have been employed for recording released neurotransmitter molecules and all-or-none action potentials from living cells. Specifically, we will overview how DBMs can resolve localized exocytotic events from subcellular compartments using high-density microelectrode arrays (MEAs), or monitoring oxidizable neurotransmitter release from populations of cells in culture and tissue slices using low-density MEAs. Interfacing DBMs with excitable cells is currently leading to the promising opportunity of recording electrical signals as well as creating neuronal interfaces through the same device. Given the recent increasingly growing development of newly available DBMs of various geometries to monitor electrical activity and neurotransmitter release in a variety of excitable and neuronal tissues, the discussion will be limited to planar DBMs.

Quantal Release of Dopamine and Action Potential Firing Detected in Midbrain Neurons by Multifunctional Diamond-Based Microarrays

“…Micro-graphitic single-crystal diamond multielectrode arrays (μG-SCD-MEAs) are a powerful sensor for investigating neurosecretion in living cells (Picollo et al, 2013, 2015b). Previous findings have demonstrated their ability to monitor spontaneous and evoked quantal catecholamine release from cultured mouse and bovine adrenal chromaffin cells (Picollo et al, 2016b) as well as from fresh mouse adrenal slices (Picollo et al, 2016a; Carabelli et al, 2017). Besides providing simultaneous recordings from a variety cells, which have been plated and cultured on the planar array for a number of days, μG-SCD-MEAs possess high-time resolution and sensitivity for the detection of amperometric events with different shape, such as the small amplitude, or previously identified “stand-alone-foot” events (Picollo et al, 2016a).…”

Electrochemical measurement of quantal exocytosis using microchips

“…Diamond is also highly transparent over a wide range of wavelengths, and can be doped with boron to become conductive while maintaining reasonable transparency (see (15) for a review). Examples of 350 nm thin boron-doped electrode layer grown on undoped nanocrystalline diamond date back to 2010 (32, 33).…”

“…More recently, high-temperature glass was used for diamond growth instead of sapphire or quartz. This strategy resolved issues of delamination and fractures and increased transparency by 50% in the visible to the near-UV range, thus allowing the excitation of fluorescent probes (15, 36). An additional method for BDD electrode fabrication consists in growing BDD electrode on a silicon substrate and bond the BDD electrode to a CMOS device with benzocyclobutene, followed by etching processes and deposition of connecting metals.…”

Neuron Adhesion on Diamond: Competition between Polymer Treatment and Surface Morphology

“…The successful construction of neuroelectrodes is mainly given by the ability to create an efficient interface between the electrode material and neural cells or tissues. Recently, diamond became an atractive material of choice for construction of neuroelectrodes 1,2 and neurointerfaces [3][4][5][6][7] and their applications as retinal prosthesis 8,9 . The material characteristics of diamond combines several aspects that could improve the performance of neuroelectrodes.…”

“…The B27-supplement suppresses the glial cells growth to achieve < 0.5% of the glial cells in the culture37 . After separation and cleaning steps the cells were centrifuged (5 min, 1000 rpm), counted and plated onto samples coated with PEI, PEI+laminin or PDL, PLD +laminin at a density from 0.5×10 6 to 1×106 cells per 1 ml in a volume 100 µl (glass) and 50 µl (nanocrystalline diamond). The medium was replaced 24 h after culturing day in vitro (DIV1) with fresh Neurobasal medium, and then half of the maintenance medium was replaced every 3-4 days.…”