Biomedical subjects

Sarah Ward-Jones

Publications and source records attributed to Sarah Ward-Jones.

3 recordsLinked to original sources

PubMed2005

Boron-doped diamond microdisc arrays: electrochemical characterisation and their use as a substrate for the production of microelectrode arrays of diverse metals (Ag, Au, Cu)via electrodeposition.

A novel boron-doped diamond (BDD) microelectrode array is characterised with electrochemical and atomic force microscopic techniques. The array consists of 40 micron-diameter sized BDD discs which are separated by 250 microns from their nearest neighbour in a hexagonal arrangement. The conducting discs can be electroplated to produce arrays of copper, silver or gold for analytical purposes in addition to operating as an array of BDD-microelectrodes. Proof-of-concept is shown for four separate examples; a gold plated array for arsenic detection, a copper plated array for nitrate analysis, a silver plated array for hydrogen peroxide monitoring and last, cathodic stripping voltammetry for lead at the bare BDD-array.

Arsenic↗

PubMed2005

Acoustically fabricated random microelectrode assemblies.

We report the insonation of bismuth, silver, copper and tungsten metal particles suspended in octane in the vicinity of a glassy carbon electrode. AFM and voltammetry reveal that metal particles are immobilised onto the electrode substrate. In the case of bismuth, silver and copper, the possible melting of the metal particles due to the high sonochemical conditions cannot unambiguously be ruled out. However, it is likely that the immobilisation of the metal particles occurs predominantly through mechanical attachment due to the high rates of mass transport, evidenced from the fact that tungsten can be immobilised at a glassy carbon surface which has a melting point (mp 3410 degrees C) outside the likely sonochemical conditions. The immobilised particles are found to be in electrical contact with the glassy carbon electrodes which can then act as random assemblies of microelectrodes. Proof-of-concept for use in electro-analysis is examined for the possible detection of arsenic and cadmium at a silver and bismuth random microelectrode assemblies, respectively. This approach suggests a simple generic methodology for the construction of microelectrode assemblies via abrasive attachment induced by insonation with power ultrasound.

Journal Article↗

PubMed2005

Novel methods for the production of silver microelectrode-arrays: their characterisation by atomic force microscopy and application to the electro-reduction of halothane.

A new method is proposed for the simple preparation of random silver micro and nano-electrode arrays. This employs acoustic streaming directed at a glassy carbon surface to "mechanically" attach particles from a suspension of metal colloidal or other small particles. The particles tend to adhere to the substrate at points of imperfection such as scratches, crevices etc. These arrays are compared with arrays formed by the electro-deposition of silver at a glassy carbon substrate, with the silver being partially stripped off, leaving a stable micro and nanoparticle array on the surface. Both surfaces are characterised using optical and atomic force microscopy. The two types of electrodes are evaluated to their analytical utility via the electrochemical reduction of halothane and their performance compared with that of a silver macroelectrode. A notable increase in sensitivity and peak current is observed.

Journal Article↗