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A Feasibility Study of a Capacitive Biosensor for Direct Detection of DNA Hybridization
Author(s) -
Berggren Christine,
Stålhandske Per,
Brundell Jan,
Johansson Gillis
Publication year - 1999
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199903)11:3<156::aid-elan156>3.0.co;2-o
Subject(s) - oligonucleotide , biosensor , monolayer , dna , nucleic acid , chemistry , oligomer restriction , covalent bond , dna–dna hybridization , hybridization probe , selectivity , microbiology and biotechnology , biochemistry , biology , organic chemistry , catalysis
This preliminary study was performed to prove the feasibility of a direct capacitive DNA biosensor for detection of nucleic acids. Two different methods for immobilization of the oligonucleotide probes were used. The first type of sensor was composed of a gold rod with a self‐assembled monolayer of a 26‐base long oligonucleotide probe, modified with an SH‐group at the 5′‐end. Coverage studies showed that only around 20% of the surface was covered, probably due to the bulky nature of the probes. Hybridization studies performed in a flow‐through cell showed selectivity towards a DNA sample containing single stranded fragments of cytomegalo virus (CMV) possessing a complementary sequence. As few as 25 molecules could be detected at sample concentrations of 0.2attomolar with an injection volume of 250 μL. Controls with fragments of double‐stranded CMV and single‐stranded hepatitis B virus and tyrosinase mRNA gave all lower responses. The other type of sensor was modified by covalent immobilization of a phosphorylated 8‐base long oligonucleotide probe to a self‐assembled monolayer of cysteamine. This biosensor also showed selectivity against single stranded fragments of CMV and also in this case as few as 25 molecules could be detected.