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A miniaturised electrochemical affinity assay based on a wall-free sample droplet and micro-dispensing of the redox-labelled binding partner

Mosbach, M.; Laurell, Thomas LU ; Nilsson, J.; Csöregi, Elisabeth LU and Schuhmann, W. (2001) In Biosensors & Bioelectronics 16(9-12). p.611-620
Abstract
An affinity-assay was developed that is based on the modulation of the diffusion coefficient of a redox-labelled hapten upon complementary recognition of the analyte leading to an increase of molecular weight and hence to a decrease of the diffusion coefficient. The slower diffusion is monitored by means of cyclic voltammetry. In order to demonstrate the feasibility of this assay format, recognition of biotin by streptavidin has been chosen as a model system. Labelling of biotin was achieved by covalent binding of a ferrocene derivative to the biotin unit. To reduce the consumption of expensive compounds and to allow automatisation of the assay a novel miniaturised set-up was developed based on a wall-free sample droplet which forms the... (More)
An affinity-assay was developed that is based on the modulation of the diffusion coefficient of a redox-labelled hapten upon complementary recognition of the analyte leading to an increase of molecular weight and hence to a decrease of the diffusion coefficient. The slower diffusion is monitored by means of cyclic voltammetry. In order to demonstrate the feasibility of this assay format, recognition of biotin by streptavidin has been chosen as a model system. Labelling of biotin was achieved by covalent binding of a ferrocene derivative to the biotin unit. To reduce the consumption of expensive compounds and to allow automatisation of the assay a novel miniaturised set-up was developed based on a wall-free sample droplet which forms the electrochemical cell with typical volumes of up to 10 mul. This droplet is dispensed by means of a step-motor driven syringe pump through a specially designed electrode holder spanning the gap between a micro-working electrode and a macroscopic counter electrode. By means of a piezo-driven micro-dispenser a predefined number of nano-droplets (100 pl volume each) containing the redox-labelled hapten are shot into the sample droplet. By this, any physical contact and hence any cross-contamination between the sample and the reagent solution could be avoided. Signal amplification can be achieved by redox recycling between the micro-electrode and the perpendicular positioned macroscopic counter electrode. (C) 2001 Elsevier Science B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
AVIDIN, TECHNOLOGY, MALDI, BIOTIN INTERACTION, CAPILLARY-ELECTROPHORESIS, FLOW-THROUGH DISPENSER, streptavidin, miniaturisation, micro-dispenser, immunoassay, biotin, diffusion coefficient
in
Biosensors & Bioelectronics
volume
16
issue
9-12
pages
611 - 620
publisher
Elsevier
external identifiers
  • wos:000172169500002
  • scopus:0034777036
ISSN
1873-4235
DOI
language
English
LU publication?
yes
id
7539ee43-ad99-4ce7-97ef-de2b67eaf944 (old id 2376417)
date added to LUP
2012-03-23 09:10:26
date last changed
2018-05-29 09:58:33
@article{7539ee43-ad99-4ce7-97ef-de2b67eaf944,
  abstract     = {An affinity-assay was developed that is based on the modulation of the diffusion coefficient of a redox-labelled hapten upon complementary recognition of the analyte leading to an increase of molecular weight and hence to a decrease of the diffusion coefficient. The slower diffusion is monitored by means of cyclic voltammetry. In order to demonstrate the feasibility of this assay format, recognition of biotin by streptavidin has been chosen as a model system. Labelling of biotin was achieved by covalent binding of a ferrocene derivative to the biotin unit. To reduce the consumption of expensive compounds and to allow automatisation of the assay a novel miniaturised set-up was developed based on a wall-free sample droplet which forms the electrochemical cell with typical volumes of up to 10 mul. This droplet is dispensed by means of a step-motor driven syringe pump through a specially designed electrode holder spanning the gap between a micro-working electrode and a macroscopic counter electrode. By means of a piezo-driven micro-dispenser a predefined number of nano-droplets (100 pl volume each) containing the redox-labelled hapten are shot into the sample droplet. By this, any physical contact and hence any cross-contamination between the sample and the reagent solution could be avoided. Signal amplification can be achieved by redox recycling between the micro-electrode and the perpendicular positioned macroscopic counter electrode. (C) 2001 Elsevier Science B.V. All rights reserved.},
  author       = {Mosbach, M. and Laurell, Thomas and Nilsson, J. and Csöregi, Elisabeth and Schuhmann, W.},
  issn         = {1873-4235},
  keyword      = {AVIDIN,TECHNOLOGY,MALDI,BIOTIN INTERACTION,CAPILLARY-ELECTROPHORESIS,FLOW-THROUGH DISPENSER,streptavidin,miniaturisation,micro-dispenser,immunoassay,biotin,diffusion coefficient},
  language     = {eng},
  number       = {9-12},
  pages        = {611--620},
  publisher    = {Elsevier},
  series       = {Biosensors & Bioelectronics},
  title        = {A miniaturised electrochemical affinity assay based on a wall-free sample droplet and micro-dispensing of the redox-labelled binding partner},
  url          = {http://dx.doi.org/},
  volume       = {16},
  year         = {2001},
}