A Novel Electrochemical Nitric Oxide Sensor: Aligned RuO2 Nanowires Deposited on Pt filament

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We fabricated a novel electrochemical NO sensor by depositing aligned ruthenium oxide (RuO2) nanowires on a fine Pt filament. This device exhibited a high current density and a low detection limit for NO in aqueous solution by combining the advantages of the sensitivity of Ru to NO and the high ratio of surface area to volume that is characteristic of nanoscale materials. The RuO2 nanowires were deposited on the Pt filament by two-step chemical vapor deposition (CVD). In the first step, Ru was deposited on the inner wall of a quartz tube furnace by decomposing ruthenium carbonyl at 150°C. In the second step, the deposited Ru was then vaporized at high temperature (950-1000°C) and allowed to condense on a substrate (silicon (Si) wafer or Pt filament) placed at the cooler end of the quartz tube. The X-ray diffraction (XRD) pattern of the condensate on the Si wafer (Fig.1) was consistent with RuO2, and the scanning electron microscope(SEM) revealed aligned nanowires approximately 50-70 nM in diameter and 800-900 nm long (Fig.2). The nanowire-modified Pt filament was utilized as an amperometric electrode to detect the NO gas dissolved in phosphate-buffered saline (PBS) and demonstrated a great increase in current density compared to a bare Pt electrode of comparable diameter (Fig.3). The detection limit was less than 1.9nM (with a signal-to-noise ratio >3). It is expected that this sensor, with further modification, can be applied to biological systems in vivo to measure pM concentrations of NO in physiological states

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Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2005 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: May 8, 2005
Pages: 434 - 437
Industry sectors: Medical & Biotech | Sensors, MEMS, Electronics
Topics: Biomaterials, Chemical, Physical & Bio-Sensors
ISBN: 0-9767985-0-6