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Affinity biosensors...
Affinity biosensors based on a capacitive transducer
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- Berggren, Christine (författare)
- Lund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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(creator_code:org_t)
- 1998
- Engelska 118 s.
- Relaterad länk:
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https://lup.lub.lu.s...
Abstract
Ämnesord
Stäng
- 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.
Ämnesord
- NATURVETENSKAP -- Kemi -- Analytisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Analytical Chemistry (hsv//eng)
Nyckelord
- self-assembled monolayers
- capacitance
- heavy metal ion
- non-labeled
- nucleic acid
- DNA biosensor
- Biosensor
- immunosensor
- Analytical chemistry
- Analytisk kemi
Publikations- och innehållstyp
- dok (ämneskategori)
- vet (ämneskategori)
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