Construction of DNA biosensor at glassy carbon surface modified with 4-aminoethylbenzenediazonium salt.
A simple, label-free electrochemical impedance-spectroscopy method for sequence-specific detection of DNA using a 4-aminoethylbenzenediazonium (AEBD) salt as a binder for amino-modified probe DNA is reported. This novel method simplifies the anchoring of DNA at the GC surface and opens new ways for the detection of hybridization. The hybridization of target DNA, without and with mismatches, with the probe DNA anchored at the GC surface modified with AEBD, greatly increases the interfacial electron transfer resistance at the double-stranded DNA modified electrodes for the redox couple Fe(CN)(6)(3-/4-). The resistance was measured using electrochemical impedance spectroscopy. The sensor response increased linearly with logarithm of concentration of target DNA in the range 2×10(-12)÷2×10(-6) M. The obtained quantification limit was circa 6.5×10(-17) mole in a 7 μL droplet and corresponded to a concentration of 9.2×10(-12) M of target DNA in the sample. This limit is equivalent to the detection of circa 4×10(7) copies of DNA in a 7 μL droplet or circa 5.7×10(12) DNA copies in one litre of sample.
Department of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, Poland.
Agata
A
Kowalczyk
Anna
A
Nowicka
Rafal
R
Jurczakowski
Michal
M
Fau
Agata
A
Krolikowska
Zbigniew
Z
Stojek
D015374:Biosensing Techniques / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics*; D003979:Diazonium Compounds / Q000737:chemistry*; D058266:Dielectric Spectroscopy / Q000295:instrumentation; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000737:chemistry; D013499:Surface Properties
D020099:Coated Materials, Biocompatible; D003979:Diazonium Compounds; D004247:DNA