Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 3435561

A microelectronic conductimetric biosensor.

L D Watson·P Maynard·D C Cullen·R S Sethi·J Brettle·C R Lowe
View original source ↗Export metadata ↓

Abstract

The fabrication and operation of a microelectronic conductimetric biosensor is described. The device monitors the change in solution conductance occasioned by the catalytic action of enzymes immobilised over a planar conductance cell comprising serpentined and interdigitated metal conductor tracks. The output of the instrument was linear over a 3 min period on addition of urea to a sample cell overlaid with immobilised urease. The responses to any given urea concentration were reproducible to within approximately +/- 1%. The device responds to urea present in serum samples.

Explore related subjects

ElectrochemistryEnzymes, ImmobilizedMicrochemistryUreaUreaseJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L D Watson, P Maynard, D C Cullen, R S Sethi, J Brettle, C R Lowe. A microelectronic conductimetric biosensor.. https://doi.org/10.1016/s0265-928x(87)80003-2

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2001

Imaging localized horseradish peroxidase on a glass surface with scanning electrochemical/ chemiluminescence microscopy.

Scanning electrochemical/chemiluminescence microscopy (SECM/SCLM) was developed for simultaneous imaging of chemiluminescence and topography of immobilized horseradish peroxidase (HRP) on a glass substrate. When the SECM tip for electrochemical generation of H2O2 scanned over the immobilized spot in an aqueous luminol solution, the immobilized enzymes catalyzed the oxidation of luminol to emit chemiluminescence, which was detected by a photon counter. The photon-counting intensity was plotted against the position of the tip to give a two-dimensional image, indicating the activity of immobilized enzymes. Since the current was sensitive to the topography of substrate, the topography image was also obtained by mapping the oxygen reduction current.

Electrochemistry↗
PubMed2001

Electrochemically actuated mercury pump for fluid flow and delivery.

This paper describes the development of a prototype pumping system with the potential for incorporation into miniaturized, fluid-based analytical instruments. The approach exploits the well-established electrocapillarity phenomena at a mercury/electrolyte interface as the mechanism for pump actuation. That is, electrochemically induced changes in the surface tension of mercury result in the pistonlike movement of a mercury column confined within a capillary. We present herein theoretical and experimental assessments of pump performance. The design and construction of the pump are detailed, and the potential attributes of this design, including the generated pumping pressure, flow rate, and power consumption, are discussed. The possible miniaturization of the pump for use as a field-deployable, fluid-delivery device is also briefly examined.

Electrochemistry↗
PubMed2000

Electrochemically controlled hydrogen bonding. o-Quinones as simple redox-dependent receptors for arylureas.

9,10-Phenanthrenequinone and acenaphthenequinone are shown to act as simple redox-dependent receptors toward aromatic ureas in CH(2)Cl(2) and DMF. Reduction of the o-quinones to their radical anions greatly increases the strength of hydrogen bonding between the quinone carbonyl oxygens and the urea N-hydrogens. This is detected by large positive shifts in the redox potential of the quinones with no change in electrochemical reversibility upon addition of urea guests. Cyclic voltammetric studies with a variety of possible guests show that the effect is quite selective. Only guests with two strong hydrogen donors, such as O-H bonds or amide N-H bonds, that are capable of simultaneously interacting with both carbonyl oxygens give large shifts in the redox potential of the quinones. The electronic character and conformational preference of the guest are also shown to significantly affect the magnitude of the observed potential shift. In the presence of strong proton donors the electrochemistry of the quinone becomes irreversible indicating that proton transfer has taken place. Experiments with compounds of different acidity show that the pK(a) of the protonated quinone radical is about 15 on the DMSO scale, >4 pK(a) units smaller than that of 1,3-diphenylurea. This is further proof that hydrogen bonding and not proton transfer is responsible for the large potential shifts observed with this and similar guests.

Electrochemistry↗