Simultaneous Fluorescent and Amperometric Detection Of Catecholamine Release From Neuroendocrine Cells With Transparent Diamond MEAs (original) (raw)
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Diamond Micro-Electrode Arrays (MEAs): A new route for in-vitro applications
Microelectrode arrays (MEAs) are extracellular devices allowing both recording and electrical stimulation of neuronal or cardiac cells. Interfacing cellular networks with MEAs leads to a better knowledge and understanding of the mechanisms of biological tissue and can be used for restorative purposes using neural prosthesis. We report the fabrication of in vitro 8×8 and 4×15 planar boron-doped nanocrystalline diamond (BNCD) MEAs using microtechnology. The BNCD for our MEA electrodes have been characterized electrochemically and we show that these devices offer good recording properties as compared to other standard electrode materials (such as Ti-Pt or Au).
Transparent diamond microelectrodes for biochemical application
Diamond and Related Materials, 2010
In this investigation a technology has been developed to use diamond electrodes in Micro Electrode Arrays (MEAs) on a transparent sapphire substrate, thus combining the outstanding electrochemical properties of boron-doped diamond electrodes (BDD) with the transparency needed for simultaneous fluorescence analysis. Nanodiamond films were grown on double side polished sapphire substrates by hot filament CVD (HFCVD) and Bias Enhanced Nucleation (BEN). A simple four microelectrode array (quadrupole) has been fabricated, fully characterized in optical and electrochemical properties, and tested with adrenal chromaffin cells, identifying amperometric spikes by the four recording diamond electrodes, corresponding to the oxidation current of catecholamine molecules.
Biosensors & Bioelectronics, 2010
The quantal release of oxidizable molecules can be successfully monitored by means of polarized carbon fiber microelectrodes (CFEs) positioned in close proximity to the cell membrane. To partially overcome certain CFE limitations, mainly related to their low spatial resolution and lack of optical transparency, we developed a planar boron-doped nanocrystalline diamond (NCD) prototype, grown on a transparent sapphire wafer. Responsiveness to applied catecholamines as well as the electrochemical and optical properties of the NCD-based device were first characterized by cyclic voltammetry and optical transmittance measurements. By stimulating chromaffin cells positioned on the device with external KCl, well-resolved quantal exocytotic events could be detected either from one NCD microelectrode, or simultaneously from an array of four microelectrodes, indicating that the chip is able to monitor secretory events (amperometric spikes) from a number of isolated chromaffin cells. Spikes detected by the planar NCD device had comparable amplitudes, kinetics and vesicle diameter distributions as those measured by conventional CFEs from the same chromaffin cell.
Polycrystalline-Diamond MEMS Biosensors Including Neural Microelectrode-Arrays
Biosensors, 2011
Diamond is a material of interest due to its unique combination of properties, including its chemical inertness and biocompatibility. Polycrystalline diamond (poly-C) has been used in experimental biosensors that utilize electrochemical methods and antigen-antibody binding for the detection of biological molecules. Boron-doped poly-C electrodes have been found to be very advantageous for electrochemical applications due to their large potential window, low background current and noise, and low detection limits (as low as 500 fM). The biocompatibility of poly-C is found to be comparable, or superior to, other materials commonly used for implants, such as titanium and 316 stainless steel. We have developed a diamond-based, neural microelectrode-array (MEA), due to the desirability of poly-C as a biosensor. These diamond probes have been used for in vivo electrical recording and in vitro electrochemical detection. Poly-C electrodes have been used for electrical recording of neural activity. In vitro studies indicate that the diamond probe can detect norepinephrine at a 5 nM level. We propose a combination of diamond micro-machining and surface functionalization for manufacturing diamond pathogen-microsensors.
Progress in transparent diamond microelectrode arrays
physica status solidi (a), 2015
Diamond multi electrode arrays (MEAs) and ultra-micro electrode array (uMEA) fabricated from boron-doped nanocrystalline (BNCD) thin-films, show excellent performances when detecting cell activity in both amperometric and potentiometric applications. Furthermore they are suitable for delivering electrical stimulation to elicit bioelectric events. Results obtained with our previous 9-channels uMEA for single cells at high spatial resolution, and 16channels MEA for multicellular samples, validated the signal quality of diamond MEAs in comparison with competing technologies. The latest progresses are reported in this paper were we describe a new generation of devices with enhanced performances: a 12-channel uMEA for recordings from a single cell at high spatial resolution, and a 64-channel MEA to accommodate larger multicellular samples. The technology is based on a 200 mm thin high-temperature glass with the same thermal expansion coefficient of silicon and a spin-on seeding method. Preliminary experiments show excellent electrodes activity and a strongly improved transparency.
Diamond microelectrodes for amperometric detection of secretory cells activity
2009
Diamond is the only transparent semiconductor electrode material used in heavy duty electrochemistry and therefore also an attractive material for microelectrode arrays in biochemistry. Three configurations are described: (1) single crystalline diamond (SCD), with a substrate size of less than 4mm x 4mm, serving as ideal reference material, (2) nanodiamond (NCD) thin films on silicon substrates, representing an application of the commonly used diamond MEMS technology and (3) NCD thin films on sapphire, sapphire being the standard substrate for GaN optoelectronics and electronics. A basic electrode array (quadropole MEA) has been developed for this investigation. For optimized deposition conditions, the influence of grain boundaries could be widely suppressed and comparable electrode characteristics could be obtained for all cases. In the diamond-on-Si case, fragile membranes need to be etched for optical transparency. Full advantage of the diamond electrode properties combined with the biological requirements is therefore only obtained by the diamond-on-sapphire system. Preliminary results of the amperometric detection of secretory cells activity are presented including a first comparison with discrete carbon fiber electrodes.
Sensors, 2012
We report on the fabrication and characterization of an 8 × 8 multichannel Boron Doped Diamond (BDD) ultramicro-electrode array (UMEA). The device combines both the assets of microelectrodes, resulting from conditions in mass transport from the bulk solution toward the electrode, and of BDD's remarkable intrinsic electrochemical properties. The UMEAs were fabricated using an original approach relying on the selective growth of diamond over pre-processed 4 inches silicon substrates. The prepared UMEAs were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results demonstrated that the electrodes have exhibited a very fast electrode transfer rate (k 0 ) up to 0.05 cm•s −1 (in a fast redox couple) and on average, a steady state limiting current (in a 0.5 M potassium chloride aqueous solution containing OPEN ACCESS Sensors 2012, 12 7670 1 mM Fe(CN) 6 4− ion at 100 mV•s −1 ) of 1.8 nA. The UMEAs are targeted for electrophysiological as well as analytical applications.
Transparent microelectrode array in diamond technology
2009
We report on the development of a diamond-on-sapphire microelectrode quadrupole array, substituting the commonly used inert metal electrode material by nanocrystalline diamond (NCD). This allows to combine the transparency (desired for fluorescence analysis) with the properties of an inert quasi-metallically doped diamond electrode. The NCD film was nucleated by BEN (Bias Enhanced Nucleation) on double side polished sapphire substrates and outgrown by hot filament CVD. Early quadrupole results on isolated adrenal chromaffin cells show the detection of amperometric signals corresponding to the quantal release of catecholamines contained in a single nanometric secretory vesicle.
A diamond-based biosensor for the recording of neuronal activity
Biosensors & Bioelectronics, 2009
We have developed a device for recording the extracellular electrical activity of cultured neuronal networks based on a hydrogen terminated (H-terminated) conductive diamond. GT1-7 cells, a neuronal cell line showing spontaneous action potentials firing, could maintain their functional properties for days in culture when plated on the H-terminated diamond surface. The recorded extracellular electrical activity appeared in the form of well-resolved bursts of fast and slow biphasic signals with a mean duration of about 8 ms for the fast and 60 ms for the slow events. The time courses of these signals were in good agreement with those recorded by means of conventional microelectrode array (MEAs) and with the negative derivative of the action potentials intracellularly recorded with the patch clamp technique from single cells. Thus, although hydrophobic in nature, the conductive H-terminated diamond surface is able to reveal the spontaneous electrical activity of neurons mainly by capacitative coupling to the cell membrane. Having previously shown that the optical properties of H-terminated diamond allow to record cellular activity by means of fluorescent probes (Ariano, P., Baldelli, P., Carbone, E., Giardino, A., Lo Giudice, A., Lovisolo, D., Manfredotti, C., Novara, M., Sternschulte, H., Vittone, E., 2005. Diam. Relat. Mater. 14, 669–674), we now provide evidence for the feasibility of using diamond-based cellular biosensors for multiparametrical recordings of electrical activity from living cells.
Boron doped diamond biotechnology: from sensors to neurointerfaces
Faraday Discuss., 2014
Boron doped nanocrystalline diamond is known as a remarkable material for the fabrication of sensors, taking advantage of its biocompatibility, electrochemical properties, and stability. Sensors can be fabricated to directly probe physiological species from biofluids (e.g. blood or urine), as will be presented. In collaboration with electrophysiologists and biologists, the technology was adapted to enable structured diamond devices such as microelectrode arrays (MEAs), i.e. common electrophysiology tools, to probe neuronal activity distributed over large populations of neurons or embryonic organs. Specific MEAs can also be used to build neural prostheses or implants to compensate function losses due to lesions or degeneration of parts of the central nervous system, such as retinal implants, which exhibit real promise as biocompatible neuroprostheses for in vivo neuronal stimulations. New electrode geometries enable high performance electrodes to surpass more conventional materials f...