Boron-doped diamond nano/microelectrodes for biosensing and in vitro measurements (original) (raw)
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Journal of The Electrochemical Society, 2012
Boron doped diamond (BDD) electrodes are extremely promising in the field of biomedical applications as they exhibit a unique combination of properties. Despite these advantages, BDD electrodes are prone to fouling when used in biological fluids (urine, blood plasma), and synthetic fluids. We propose a electrochemical (EC) treatment where a train of short cathodic and/or anodic pulses are applied to clean fouled electrodes. This technique can be used to retrieve the lost reactivity, characterized by electron transfer rate k 0 of the boron doped diamond electrodes, thereby enhancing their reusability over long period of measurements without degradation of the signal, thus significantly extending the field of monitoring and surveying applications. The technique does not require the use of a specific medium and thus can be directly performed in the probed fluid. Although an aqueous electrolyte containing non-electroactive species is preferred for EC activation, it can also be done in biological fluids such as blood, urine etc, thereby opening the field for in-vivo analysis. Through Electrochemical impedance spectroscopy (EIS) it was observed that the k 0 value was increased up to 0.1 cm s −1 after the activation process. This technique improves the sensitivity, reproducibility and lifetime of the electrodes to a considerable extent.
Analytical Chemistry, 2003
The fabrication and characterization of boron-doped diamond microelectrodes for use in electrochemical detection coupled with capillary electrophoresis (CE-EC) is discussed. The microelectrodes were prepared by coating thin films of polycrystalline diamond on electrochemically sharpened platinum wires (76-, 25-, and 10-µm diameter), using microwave-assisted chemical vapor deposition (CVD). The diamond-coated wires were attached to copper wires (current collectors), and several methods were explored to insulate the cylindrical portion of the electrode: nail polish, epoxy, polyimide, and polypropylene coatings. The microelectrodes were characterized by scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry. They exhibited low and stable background currents and sigmoidally shaped voltammetric curves for Ru(NH 3 ) 6 3+/2+ and Fe(CN) 6 3-/4at low scan rates. The microelectrodes formed with the large diameter Pt and sealed in polypropylene pipet tips were employed for end-column detection in CE. Evaluation of the CE-EC system and the electrode performance were accomplished using a 10 mM phosphate buffer, pH 6.0, run buffer, and a 30-cm-long fused-silica capillary (75-µm i.d.) with dopamine, catechol, and ascorbic acid serving as test analytes. The background current (∼100 pA) and noise (∼3 pA) were measured at different detection potentials and found to be very stable with time. Reproducible separation (elution time) and detection (peak current or area) of dopamine, catecho,l and ascorbic acid were observed with response precisions of 4.1% or less. Calibration curves constructed from the peak area were linear over 4 orders of magnitude, up to a concentration between 0.1 and 1 mM. Mass limits of detection for dopamine and catechol were 1.7 and 2.6 fmol, respectively (S/N ) 3). The separation efficiency was ∼33 000, 56 000, and 98 000 plates/m for dopamine, catechol, and ascorbic acid, respectively. In addition, the separation and detection of 1-and 2-naphthol in 160 mM borate buffer, pH 9.2, was investigated. Separation of these two analytes was achieved with efficiencies of 118 000 and 126 000 plates/m, respectively.
Physical Chemistry Chemical Physics, 2011
Fouling of electrode surfaces by electrode reaction products or by biological spectator species is known to inactivate electrochemical sensors and thus limit their use in biological conditions. Here we present an investigation on the stability of boron doped diamond (BDD) electrodes with different levels of doping. Three different doping levels were used (0.1, 1 and 5% in the carbon phase). The highly doped (5%) BDD is of particular interest as it is here used for the first time for biological applications. Three different redox reactions were examined based on their electrode reaction characteristics: ruthenium(III) hexaammine (outer sphere), ferrocyanide (suface dependent), dopamine (adsorption mediated). The effect of albumin at blood concentration was studied. All results were compared with glassy carbon.
All-diamond microelectrodes as solid state probes for localized electrochemical sensing
Analytical chemistry, 2015
The fabrication of an all-diamond microprobes demonstrated for the first time. This ME assembly consists on an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapour deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was non-electrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the mi...
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...
Electroanalytical applications of boron-doped diamond microelectrode arrays
Talanta, 2006
The electrochemical characteristics of a novel all diamond fabricated boron-doped diamond microelectrode array (BDD-MEA) are critically appraised. The voltammetric response of simple electron transfer processes has been investigated and found to generate sigmoidal voltammetric curves. Furthermore, the device has been utilized for various analytical applications including, the direct detection of 4-nitrophenol over the concentration range 1.8-9.2 M, manganese over the range 0.1-4.8 M and the indirect determination of sulfide producing a limit of detection of 23 M.
Analytica Chimica Acta, 2019
This review summarizes progress in electroanalysis of organic compounds and biomacromolecules by means of bare BDD-based electrodes for the period of 2009-2018. New trends, which have emerged in the reported decade and which have improved their performance in batch voltammetric and amperometric methods and electrochemical detection in liquid flow techniques are commented. Importance of BDD surface termination, effect of boron doping level, and utilization of adsorption of analytes on BDD surfaces enabling development of adsorptive voltammetric techniques are addressed. Further, possibilities of
Electrochimica Acta
Recently, the electrochemical applications of boron-doped diamond (BDD) electrodes attract much attention not only in the field of electrochemistry, but also in other areas such as functional materials, analytical and environmental chemistry, biomedical and biological sciences. Since the properties of BDD are combined with its inert surface characteristics, the BDD electrodes display intriguing electrochemical features, inter alia, the widest solvent window of all electrode materials in aqueous solutions, low background and capacitive currents, reduced fouling and the ability to withstand extreme potentials, while at the same time retaining the excellent mechanical robustness. Thus, BDD is slowly rising in prominence in the electrochemical arena, predominantly where longevity and low maintenance are key attributes [1,2]. The electrode preparation step is often applied to remove sp 2carbon impurities saturating the BDD electrode during the CVD process [3,4], which can be found in particular, but are not limited to, inter-grain regions [5]. Usually, the pretreatment of BDD electrode surface for electrochemical measurements is carried out via one or several of the following mechanisms: (I) mechanical polishing and lapping; (II) acid washing and rehydrogenation; (III) heat treatment; and (IV) electrochemical polarization [6-11] (Supporting Information, Section I). These methods are often