High Frequency Acoustic STW Biosensor

Liron, Zvi; Kaushansky, Nathali; Graziani, Netzach; Keysary, Avi; Barness, Itzhak; Marx, Sharon

doi:10.1007/978-1-4615-1231-8_4

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…DNA has been reported to be metallic, semiconducting, insulating, , and even a proximity effect induced superconductor . Studies based on spectroscopic, biochemical, and biophysical methods have indicated that the DNA stack can provide a medium for charge transport. − Electron transfer through a DNA monolayer immobilized on the surface of Au was also investigated by electrochemistry when an electroactive species was either attached to the end of DNA or dissolved in the solution. , As a result, the fabrication of biosensors to detect DNA sequences and other biological species has become an interest to many scientific workers. − However, questions have been raised with regard to the role played by electrical contacts; length effects; and the manner in which electrostatic damage, residual salt concentrations, traces amount of water effect, and other contaminations may have affected these results, − in additional to the quality of DNA monolayer formed on the electrode surface. Clearly, more studies, particularly those with new experimental designs, need to be done to obtain a reliable picture of the electronic behavior of DNA.…”

Section: Introductionmentioning

confidence: 99%

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Pittman

Miao

2008

J. Phys. Chem. C

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Three aminoalkanethiols that have large electron-transfer rate constants, SH-(CH 2 ) n -NH 2 (n ) 6, 8, and 11), were individually self-assembled on Au electrodes, followed by covalent attachment of tris(2,2′bipyridyl)ruthenium(II) (Ru(bpy) 3 2+ ) moieties onto the end of the thiols. Two separate electrogenerated chemiluminescence (ECL) waves were observed upon anodic potential scanning from 0 to 1.40 V vs Ag/ AgCl (3 M KCl) over the electrode placed in 0.10 M tri-n-propylamine (TPrA)/0.10 M phosphate buffer (pH 7.4) solution. The first ECL wave, located at ∼0.88 V vs Ag/AgCl, was associated with the direct oxidation of TPrA at the electrode, and the second ECL wave, located at ∼1.12, 1.22, and 1.35 V vs Ag/AgCl for n ) 6, 8, and 11, respectively, was directly related to the oxidation of the tethered Ru(bpy) 3 2+ species. The electron transfer behavior through DNA was examined at Au electrodes, which were covalently immobilized with 15-mer and 20-mer single-stranded (ss) DNA, respectively, and then hybridized with the relevant complementary ssDNA tagged with Ru(bpy) 3 2+ ECL labels. Under the same experimental conditions described above for Au/aminoalkanethiol-Ru(bpy) 3 2+ studies, both double-stranded (ds) DNA displayed similar ECL responses, with the first ECL peak at ∼0.88 V and the second one at ∼1.22 V vs Ag/AgCl. No peak potential shift for the second ECL wave and no impact of the dsDNA on the entire electron transfer processes were observed, suggesting that complementary dsDNA helical structures can transfer electrons at a very large rate constant and that dsDNA studied were very conductive. In contrast, an electrode attached with 15-mer ssDNA-Ru(bpy) 3 2+ did not show the second ECL wave, implying that ssDNA was not electronically conductive.

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Section: Introductionmentioning

confidence: 99%

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Pittman

Miao

2008

J. Phys. Chem. C

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“…Sensitivity in DNA hybridization and other bioassays is important in clinical diagnostics, − forensic chemistry, , environmental , investigations, pharmaceutical studies, , and biological warfare agent detection. , ECL methods have been widely used in such studies because of their high sensitivity, wide dynamic range, and selectivity . A variety of techniques are available for the detection of DNA, of which electrochemical, fluorescent, and ECL active labels attached to the t-ssDNA produce the measurable signal in the analysis process. ,− Since the intensity of the measured signal is generally proportional to the amount of t-ssDNA, and traditionally only one or a few labels can be attached to one t-ssDNA, a number of approaches have been developed in which one DNA can be labeled with a large number of labels so that a higher sensitivity can be achieved. , …”

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confidence: 99%

Electrogenerated Chemiluminescence. 77. DNA Hybridization Detection at High Amplification with [Ru(bpy)₃]²⁺-Containing Microspheres

2004

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An ultrasensitive DNA hybridization detection method based on electrogenerated chemiluminescence (ECL) using polystyrene microspheres/beads (PSB) as the carrier of the ECL labels, namely, tris(2,2'-bipyridyl)ruthenium(II) tetrakis(pentafluorophenyl)borate (Ru(bpy)3[B(C6F5)4]2), is reported. Probe single-stranded DNA (p-ssDNA) was attached to the surface of magnetic beads (MB) and hybridized with target-ssDNA (t-ssDNA) with immobilized PSB containing a large number of water insoluble Ru(bpy)3[B(C6F5)4]2 species (approximately 7.5 x 10(9) molecules/bead). With this approach a large amplification factor of Ru(bpy)3[B(C6F5)4]2 molecules for each t-ssDNA can be achieved, when each PSB is attached to a limited number of t-ssDNA. The p-ssDNA-MB <--> t-ssDNA-PSB/Ru(bpy)3(2+) conjugates formed were magnetically separated from the reaction media and dissolved in MeCN containing tri-n-propylamine (TPrA) as an ECL coreactant. ECL was produced with a potential scan from 0 to 3.0 V versus Ag/Ag+, and the integrated ECL intensity was found to be linearly proportional to the t-ssDNA concentration in a range of 1.0 fM to 10 nM under optimized conditions. ECL signals associated with two base pair mismatched ssDNA and noncomplementary ssDNA can be distinguished well from the ECL signal related to the complementary DNA hybridization. A Poisson distribution is followed when a large number of MB reacts with PSB, and the minimum number of 1.0- and 2.8-microm diameter MB required to bind and magnetically separate a single 10-microm diameter PSB from the reaction solution was estimated to be three and one, respectively. The principle described in this paper could be also applied to many other ECL analyses, such as immunoassays.

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“…Studies on biosensors capable of rapidly, selectively, and sensitively detecting DNA sequences and antigen−antibody interactions have recently attracted much attention. − These kinds of biosensors, that is, DNA probe assays and immunoassays, have a wide range of applications in areas of clinical diagnostics, ,, forensic chemistry, , environmental , investigations, pharmaceutical studies, , and biological warfare agent detections . Many different types of techniques, such as electrochemical, ,,,,,, optical, ,,, radiochemical, piezoelectronic 1,2,6,20 and electrogenerated chemiluminescent (ECL) methods, ,− have been applied to accomplish these kinds of assays.…”

mentioning

confidence: 99%

Electrogenerated Chemiluminescence. 72. Determination of Immobilized DNA and C-Reactive Protein on Au(111) Electrodes Using Tris(2,2‘-bipyridyl)ruthenium(II) Labels

2003

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Anodic electrogenerated chemiluminescence (ECL) with tri-n-propylamine (TPrA) as a coreactant was used to determine DNA and C-reactive protein (CRP) by immobilizations on Au(111) electrodes using tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) labels. A 23-mer synthetic single-stranded (ss) DNA derived from the Bacillus anthracis with an amino-modified group at the 5' end position was covalently attached to the Au(111) substrate precoated with a self-assembled thiol monolayer of 3-mercaptopropanoic acid (3-MPA) in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) and then hybridized with a target ssDNA tagged with Ru(bpy)(3)(2+) ECL labels. Similarly, biotinylated anti-CRP species were immobilized effectively onto the Au(111) substrate precovered with a layer of avidin linked covalently via the reaction between avidin and a mixed thiol monolayer of 3-MPA and 16-mercaptohexadecanoic acid on Au(111) in the presence of EDAC and N-hydroxysuccinimide. CRP and anti-CRP tagged with Ru(bpy)(3)(2+) labels were then conjugated to the surface layer. ECL responses were generated from the modified electrodes described above by immersing them in a TPrA-containing electrolyte solution. A series of electrode treatments, including blocking free -COOH groups with ethanol amine, pinhole blocking with bovine serum albumin, washing with EDTA/NaCl/Tris buffer, and spraying with inert gases, were used to reduce the nonspecific adsorption of the labeled species. The ECL peak intensity was linearly proportional to the analyte CRP concentration over the range 1-24 microg/mL. CRP concentrations of two unknown human plasma/serum specimens were measured by the standard addition method based on this technique.

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High Frequency Acoustic STW Biosensor

Cited by 5 publications

References 7 publications

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Electrogenerated Chemiluminescence. 77. DNA Hybridization Detection at High Amplification with [Ru(bpy)₃]²⁺-Containing Microspheres

Electrogenerated Chemiluminescence. 72. Determination of Immobilized DNA and C-Reactive Protein on Au(111) Electrodes Using Tris(2,2‘-bipyridyl)ruthenium(II) Labels

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High Frequency Acoustic STW Biosensor

Cited by 5 publications

References 7 publications

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Examination of Electron Transfer Through DNA Using Electrogenerated Chemiluminescence

Electrogenerated Chemiluminescence. 77. DNA Hybridization Detection at High Amplification with [Ru(bpy)3]2+-Containing Microspheres

Electrogenerated Chemiluminescence. 72. Determination of Immobilized DNA and C-Reactive Protein on Au(111) Electrodes Using Tris(2,2‘-bipyridyl)ruthenium(II) Labels

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Electrogenerated Chemiluminescence. 77. DNA Hybridization Detection at High Amplification with [Ru(bpy)₃]²⁺-Containing Microspheres