Diamond microelectrodes for use in biological environments

Simultaneous detection of gastric acid and histamine release to unravel the regulation of acid secretion from the guinea pig stomach

“…Within this study we have shown the ability to conduct real-time recordings of histamine release and pH recordings simultaneously. The major advantage of using the BDD microelectrode is that is it not prone to influence by pH fluctuations, which are well known to shift oxidation potentials of the measured analyte and thus provide inaccurate responses (24).…”

“…Our data shows that the sensor responses were not affected by conducting 3 h in vitro recordings. This is partly due to the sensor materials utilized, as the BDD electrode has been shown to be less prone to electrode fouling (24,25,27). Measurements were carried out when the sensors were not in any contact with the mucosal surface, thus preventing fouling from mucus and other matrix components.…”

“…Polycrystalline BDD thin film was deposited on a 40-m diameter Pt wire (99.99%; Aldrich Chemical) by microwave-assisted chemical vapor deposition (1.5 kW, 2.54 GHz; ASTeX, Woburn, MA), as detailed previously (7,24,27). The diamond-coated Pt wire was insulated with polypropylene using a pipette tip so that a length of 100 -200 m exposed BDD was protruding at the end (7,24). The resulting microelectrode was conical cylindrical with a maximum diameter of ϳ40 m. The electrode can be reproducibly insulated with a thin and continuous polymer film using this method, but precise control of the exposed electrode length is difficult to achieve.…”

Diamond Ultramicro- and Nano-electrode Arrays

“…For the fabrication of these microelectrodes, one frequently applied approach is to coat sharpened metal wires with a thin boron-doped diamond film. The used metals are mainly from tungsten [31][32][33][34][35][36] and platinum [37,38]. Coating tungsten wires sealed in a quartz glass capillary with diamond is an alternative approach, which was developed by Martin and coworkers [39,40].…”

“…They have been applied for electrochemical sensing applications in non-aqueous [31] and aqueous solutions [32][33][34][35][36][37][38][39][40]. For example, they have been used in biological media to detect dopamine in mouse brain [33], to monitor norepinephrine release in mesenteric artery [38], to investigate the role of adenosine in the modulation of breathing within animal tissue [39], and to inspect serotonin as a neuromodulator [40]. These microelectrodes and ultramicroelectrodes have shown lower detection limits towards analytes in solution and increased signal-to-noise ratios than those obtained on planar macroscopic diamond electrodes.…”