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Affinity biosensors based on a capacitive transducer

Berggren, Christine LU (1998)
Abstract
Capacitive biosensors were developed for several analytes such as hormones, interleukines, viruses and heavy metal ions. The sensing surfaces were prepared by immobilizing the biorecognition element to self-assembled monolayers (SAMs) on gold. SAMs form spontaneously on gold by adsorption of thiols, sulfides or disulfides. After immobilization of the biorecognition element a long chain hydrocarbon thiol was used to block any uncovered spots on the surface. The electrode was mounted in a flow-system and served as working electrode in a potentiostatically controlled system. Between measurements the working electrode was held at a rest potential of 0 mv vs. an Ag/AgCl reference electrode. To measure the capacitance at the sensing... (More)
Capacitive biosensors were developed for several analytes such as hormones, interleukines, viruses and heavy metal ions. The sensing surfaces were prepared by immobilizing the biorecognition element to self-assembled monolayers (SAMs) on gold. SAMs form spontaneously on gold by adsorption of thiols, sulfides or disulfides. After immobilization of the biorecognition element a long chain hydrocarbon thiol was used to block any uncovered spots on the surface. The electrode was mounted in a flow-system and served as working electrode in a potentiostatically controlled system. Between measurements the working electrode was held at a rest potential of 0 mv vs. an Ag/AgCl reference electrode. To measure the capacitance at the sensing layer/electrolyte interface a potentiostatic step of 50 mV was applied and the resulting current response was recorded. By assuming that the current response followed that for a model consisting of a resistor and a capacitor in series the capacitance could be calculated by a linear least-squares fitting.



Immunosensors specific for hormones and interleukines were developed with detection limits around 15 femtomolar for non-labeled antigens. DNA biosensors were developed by immobilizing a short oligonucleotide probe in two different ways; either by direct self-assembling of an SH- modified oligonucleotide or by coupling an oligonucleotide to a SAM. In both cases 0.2 attomolar of a DNA virus fragment could be detected. Also heavy metal ion specific biosensors were developed by immobilizing heavy metal specific proteins on an electrode surface by the self- assembling process. The heavy metal specific proteins are believed to change conformation when heavy metal ions bind thereby resulting in a change in capacitance. The heavy metal ions Cu2+, Zn2+, Cd2+ and Hg2+ could all be detected down to femtomolar concentrations. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Renneberg, Reinhard
organization
publishing date
type
Thesis
publication status
published
subject
keywords
self-assembled monolayers, capacitance, heavy metal ion, non-labeled, nucleic acid, DNA biosensor, Biosensor, immunosensor, Analytical chemistry, Analytisk kemi
pages
118 pages
publisher
Christine Berggren, Iliongränd 11, 224 72 Lund, Sweden,
defense location
Lecture room D, Chemical Center
defense date
1998-09-25 10:15
external identifiers
  • Other:ISRN: LUNKDL/NKAK-1042/1- 118 (1998)
language
English
LU publication?
yes
id
ac9ff58e-5ed8-4b01-b8f7-f268b90e144d (old id 38906)
date added to LUP
2007-06-20 11:53:54
date last changed
2016-09-19 08:45:11
@misc{ac9ff58e-5ed8-4b01-b8f7-f268b90e144d,
  abstract     = {Capacitive biosensors were developed for several analytes such as hormones, interleukines, viruses and heavy metal ions. The sensing surfaces were prepared by immobilizing the biorecognition element to self-assembled monolayers (SAMs) on gold. SAMs form spontaneously on gold by adsorption of thiols, sulfides or disulfides. After immobilization of the biorecognition element a long chain hydrocarbon thiol was used to block any uncovered spots on the surface. The electrode was mounted in a flow-system and served as working electrode in a potentiostatically controlled system. Between measurements the working electrode was held at a rest potential of 0 mv vs. an Ag/AgCl reference electrode. To measure the capacitance at the sensing layer/electrolyte interface a potentiostatic step of 50 mV was applied and the resulting current response was recorded. By assuming that the current response followed that for a model consisting of a resistor and a capacitor in series the capacitance could be calculated by a linear least-squares fitting.<br/><br>
<br/><br>
Immunosensors specific for hormones and interleukines were developed with detection limits around 15 femtomolar for non-labeled antigens. DNA biosensors were developed by immobilizing a short oligonucleotide probe in two different ways; either by direct self-assembling of an SH- modified oligonucleotide or by coupling an oligonucleotide to a SAM. In both cases 0.2 attomolar of a DNA virus fragment could be detected. Also heavy metal ion specific biosensors were developed by immobilizing heavy metal specific proteins on an electrode surface by the self- assembling process. The heavy metal specific proteins are believed to change conformation when heavy metal ions bind thereby resulting in a change in capacitance. The heavy metal ions Cu2+, Zn2+, Cd2+ and Hg2+ could all be detected down to femtomolar concentrations.},
  author       = {Berggren, Christine},
  keyword      = {self-assembled monolayers,capacitance,heavy metal ion,non-labeled,nucleic acid,DNA biosensor,Biosensor,immunosensor,Analytical chemistry,Analytisk kemi},
  language     = {eng},
  pages        = {118},
  publisher    = {ARRAY(0x84ff930)},
  title        = {Affinity biosensors based on a capacitive transducer},
  year         = {1998},
}