Affinity biosensors based on a capacitive transducer
(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:
https://lup.lub.lu.se/record/38906
- author
- Berggren, Christine LU
- supervisor
- opponent
-
- Renneberg, Reinhard
- organization
- publishing date
- 1998
- 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 10:15:00
- external identifiers
-
- other:ISRN: LUNKDL/NKAK-1042/1- 118 (1998)
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Analytical Chemistry (S/LTH) (011001004)
- id
- ac9ff58e-5ed8-4b01-b8f7-f268b90e144d (old id 38906)
- date added to LUP
- 2016-04-04 11:35:40
- date last changed
- 2018-11-21 21:05:52
@phdthesis{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}},
keywords = {{self-assembled monolayers; capacitance; heavy metal ion; non-labeled; nucleic acid; DNA biosensor; Biosensor; immunosensor; Analytical chemistry; Analytisk kemi}},
language = {{eng}},
publisher = {{Christine Berggren, Iliongränd 11, 224 72 Lund, Sweden,}},
school = {{Lund University}},
title = {{Affinity biosensors based on a capacitive transducer}},
year = {{1998}},
}