Indicator-free electrochemical DNA hybridization biosensor (original) (raw)
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Indicator-Free Electrochemical Dna Biosensor for the Detection of Hybridisation Reaction
Sensors and Microsystems, 2002
A novel electrochemical hybridization biosensor protocol without using an external indicator is described. The oxidation signals of adenine and guanine from calf thymus double-stranded DNA (dsDNA) and calf thymus singlestranded DNA (ssDNA) was studied by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE). The oxidation signals of adenine and guanine obtained from the ssDNA modified CPE was higher than that from the dsDNA modified CPE due to the accessible unbound adenine and guanine bases. The electrochemical determination of hybridization between native capture DNA probe and target oligonucleotides and polynucleotides such as poly[G], poly[C], poly[I] and poly[A], poly[T] were also accomplished. The dependence of the peak heights of guanine and adenine signals on the number of the respective bases in oligonucleotides was observed by means of DPV. The dependence of the guanine signal upon the concentration of the target and the noncomplementary DNA sequences was also observed. The use of the intrinsic DNA electrochemical signals for monitoring hybridization events offers several advantages over the common use of carcinogenic external indicators and expensive inosine substituted capture DNA probes, such as a shorter assay time and cost-effective procedure. Performance characteristics of the biosensor are described, along with future prospects.
Biosensors and Bioelectronics, 1999
A disposable electrochemical sensor for the detection of short DNA sequences is described. Synthetic single-stranded oligonucleotides have been immobilized onto graphite screen printed electrodes with two procedures, the first involving the binding of avidinbiotinylated oligonucleotide and the second adsorption at a controlled potential. The probes were hybridized with different concentrations of complementary sequences. The formed hybrids on the electrode surface were evaluated by differential pulse voltammetry and chronopotentiometric stripping analysis using daunomycin hydrochloride as indicator of hybridization reaction. The probe immobilization step, the hybridization event and the indicator detection, have been optimized. The DNA sensor obtained by adsorption at a controlled potential was able to detect 1 g/ml of target sequence in the buffer solution using chronopotentiometric stripping analysis.
Indicator-Free Electrochemical DNA Biosensor Based on Adenine and Guanine Signals
Electroanalysis, 2002
A novel electrochemical hybridization biosensor protocol without using an external indicator is described. The oxidation signals of adenine and guanine from calf thymus double-stranded DNA (dsDNA) and calf thymus singlestranded DNA (ssDNA) was studied by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE). The oxidation signals of adenine and guanine obtained from the ssDNA modified CPE was higher than that from the dsDNA modified CPE due to the accessible unbound adenine and guanine bases. The electrochemical determination of hybridization between native capture DNA probe and target oligonucleotides and polynucleotides such as poly [G], poly[C], poly[I] and poly[A], poly[T] were also accomplished. The dependence of the peak heights of guanine and adenine signals on the number of the respective bases in oligonucleotides was observed by means of DPV. The dependence of the guanine signal upon the concentration of the target and the noncomplementary DNA sequences was also observed. The use of the intrinsic DNA electrochemical signals for monitoring hybridization events offers several advantages over the common use of carcinogenic external indicators and expensive inosine substituted capture DNA probes, such as a shorter assay time and cost-effective procedure. Performance characteristics of the biosensor are described, along with future prospects.
Electrochemical DNA hybridization sensors applied to real and complex biological samples
Biosensors and Bioelectronics, 2010
a b s t r a c t DNA hybridization biosensors, also known as genosensors, are analytical devices for the detection of specific DNA "target" sequences in solution, upon hybridization of the targets with complementary "probes" immobilized on a solid substrate. Electrochemical genosensors hold great promise to serve as devices suitable for point-of-care diagnostics and multiplexed platforms for fast, simple and inexpensive nucleic acids analysis. Although a lot of progress has been made in the past few years, the performance of genosensors in complex biological samples has been assayed in only a small fraction of published research articles. This review covers such a group of reports, from the year 2000 onwards. Special attention is played in the nature and complexity of the samples and in the way matrix effects were treated and specificity controls were performed.
Indicator based and indicator-free electrochemical DNA biosensors
… in Medicine and …, 2001
Nucleic acids have become the ultimate tools in the recognition and monitoring of many important compounds . There is a great demand for a detection system which cannot only determine specific DNA fragments, but can also determine the exact total nucleic acid content of a sample. For more than a decade, DNA biosensor technologies are under intense investigation owing to their great promise for rapid and low-cost detection of specific DNA sequences in human, viral and bacterial nucleic acids .
Analytica Chimica Acta, 2002
An electrochemical DNA biosensor based on the recognition of single stranded DNA (ssDNA) by hybridization detection with immobilized complementary DNA oligonucleotides is presented. DNA and oligonucleotides were covalently attached through free amines on the DNA bases using N-hydroxysulfosuccinimide propyl-N -ethylcarbodiimide hydrochloride (EDC) onto a carboxylate terminated alkanethiol self-assembled monolayers (SAM) preformed on a gold electrode (AuE). Differential pulse voltammetry (DPV) was used to investigate the surface coverage and molecular orientation of the immobilized DNA molecules. The covalently immobilized probe could selectively hybridize with the target DNA to form a hybrid on the surface despite the bases being attached to the SAM. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with the target. Peak currents were found to increase in the following order: hybrid-modified AuE, mismatched hybrid-modified AuE, and the probe-modified AuE which indicates the MB signal is determined by the extent of exposed bases. Control experiments were performed using a non-complementary DNA sequence. The effect of the DNA target concentration on the hybridization signal was also studied. The interaction of MB with inosine substituted probes was investigated. Performance characteristics of the sensor are described. .tr (M. Ozsoz). low-cost point-of-care detection of specific nucleic acid sequences .
Electroanalysis, 2002
A chitosan modified carbon paste electrode (ChiCPE) based DNA biosensor for the recognition of calf thymus double stranded DNA (dsDNA), single stranded DNA (ssDNA) and hybridization detection between complementary DNA oligonucleotides is presented. DNA and oligonucleotides were electrostatically attached by using chitosan onto CPE. The amino groups of chitosan formed a strong complex with the phosphate backbone of DNA. The immobilized probe could selectively hybridize with the target DNA to form hybrid on the CPE surface. The detection of hybridization was observed by using the label-free and label based protocols. The oxidation signals of guanine and adenine greatly decreased when a hybrid was formed on the ChiCPE surface. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with target. The signals of MB were investigated at dsDNA modified ChiCPE and ssDNA modified ChiCPE and the increased peak currents were observed, in respect to the order of electrodes. The hybridization of peptide nucleic acid (PNA) probes with the DNA target sequences at ChiCPE was also investigated. Performance characteristics of the sensor were described, along with future prospects.
Electrochemical enzyme-linked immunoassay in a DNA hybridization sensor
Analytica Chimica Acta, 2002
In most of the currently developed electrochemical DNA hybridization sensors short single-stranded probe DNA is immobilized on an electrode and both the hybridization and detection steps are carried out on the electrode surface. Here we use a new technology in which DNA hybridization is performed on commercially available magnetic beads and detection on solid electrodes. Paramagnetic Dynabeads Oligo(dT)25 (DBT) with
Electrochemical biosensors for DNA hybridization and DNA damage
Biosensors & Bioelectronics, 1998
Recent trends in the development of DNA biosensors for nucleotide sequence-specific DNA hybridization and for the detection of the DNA damage are briefly reviewed. Changes in the redox signals of base residues in DNA immobilized at the surface of carbon or mercury electrodes can be used as a sign of the damage of DNA bases. Some compounds interacting with DNA can produce their own redox signals on binding to DNA. Covalently closed circular (usually supercoiled) DNA attached to the electrode surface can be used for a sensitive detection of a single break of the DNA sugar-phosphate backbone and for detection of agents cleaving the DNA backbone such as hydroxyl radicals, ionizing radiation, nucleases, etc. Using the peptide nucleic acid in the biosensor recognition layer greatly increased the specificity of the DNA hybridization biosensor making it possible to detect point mutations (single-base mismatches) in DNA.
Carbon and gold electrodes as electrochemical transducers for DNA hybridisation sensors
Biosensors and Bioelectronics, 2004
Genosensor technology relying on the use of carbon and gold electrodes is reviewed. The key steps of each analytical procedure, namely DNA-probe immobilisation, hybridisation, labelling and electrochemical investigation of the surface, are discussed in detail with separate sections devoted to label-free and newly emerging magnetic assays. Special emphasis has been given to protocols that have been used with real DNA samples.