Electrochemical DNA sensor for detection of single nucleotide polymorphisms.
In recent years there has been an increased interest in using biosensors for the recognition and monitoring of molecule interactions. DNA sensors and gene chips are particularly relevant for directly applying the information gathered from the genome projects. In this work electrochemical techniques are used to develop methodologies to detect DNA polymorphisms in human genes using cytochrome P450 3A4 (CYP3A4) as a model gene. CYP3A4*1B oligonucleotides were immobilized on the surface of a gold electrode and hybridized with fully complementary oligonucleotide sequences as well as with mismatched sequences corresponding to the CYP3A4*1A reference sequence. The methodology developed is based on double-stranded DNA's ability to transport charge along nucleotide stacking. The perturbation of the double helix pi-stack introduced by a mismatched nucleotide reduces electron flow and can be detected by measuring the attenuation of the charge transfer. The methodology developed could identify CYP3A4*1A homozygotes by the 5 microC charge attenuation observed when compared with DNA samples containing at least one CYP3A4*1B allele.
Centre for Molecular and Structural Biomedicine, University of Algarve, Faro, Portugal.
Leonel P J
LP
Marques
Isa
I
Cavaco
José P
JP
Pinheiro
Vera
V
Ribeiro
Guilherme N M
GN
Ferreira
D015374:Biosensing Techniques; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004247:DNA / Q000032:analysis*; D017931:DNA Primers / Q000737:chemistry; D015342:DNA Probes; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D005838:Genotype; D006801:Humans; D009693:Nucleic Acid Hybridization / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*
D017931:DNA Primers; D015342:DNA Probes; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human