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Biosensors
Kinds of Biosensors Terms modified by Biosensors Selected AbstractsDevelopment of a Glucose Biosensor Using Advanced Electrode Modified by Nanohybrid Composing Chemically Modified Graphene and Ionic LiquidELECTROANALYSIS, Issue 11 2010Ho Yang Abstract Nanohybrids of chemically modified graphene (CMG) and ionic liquid (IL) were prepared by sonication to modify the electrode. The modified CMG-IL electrodes showed a higher current and smaller peak-to-peak potential separation than a bare electrode due to the promoted electron transfer rate. Furthermore, the glucose oxidase (GOx) immobilized on the modified electrode displayed direct electron transfer rate and symmetrical redox potentials with a linear relationship at different scan rates. The fabricated GOx/CMG-IL electrodes were developed selective glucose biosensor with respect to a sensitivity of 0.64,,A mM,1, detection limit of 0.376,mM, and response time of <5,s. [source] An Electrochemical DNA Biosensor for the Detection of the Apa I Polymorphism in the Vitamin D Receptor Gene Using Meldola's Blue as a Hybridization IndicatorELECTROANALYSIS, Issue 5 2010Nilay Aladag Abstract Electrochemical detection of nucleic acid base mismatches related to Apa I single nucleotide polymorphism (SNP) in the vitamin D receptor gene was performed successfully using 7-dimethyl-amino-1,2-benzophenoxazinium salt (Meldola's blue, MDB) with 10.9,pmol/100,,L of detection limit. MDB reduction signals obtained from probe, mismatch(probe-SNP containing target) and hybrid(probe-target) modified pencil graphite electrode(PGE) increased respectively. The sensor was able to clearly distinguish perfect match from mismatch DNA in a 30,min. detection time. Several factors affecting on the hybridization and indicator response are studied to maximize sensitivity and selectivity. The advantages of the biosensor are discussed in comparison with previous electrochemical assays for DNA hybridization. [source] Fabrication of a Sensitive Cholesterol Biosensor Based on Cobalt-oxide Nanostructures Electrodeposited onto Glassy Carbon ElectrodeELECTROANALYSIS, Issue 24 2009Abdollah Salimi Abstract Electrodeposited cobalt oxide (CoOx) nanomaterials are not only used for immobilization of cholesterol oxidase (ChOx) but also as electron transfer mediator for oxidation of H2O2 generated in the enzymatic reaction. Voltammetry and flow injection analysis (FIA) were used for determination of cholesterol. FIA determination of cholesterol with biosensors yielded a calibration curve with the following characteristics: linear range up to 50,,M, sensitivity of 43.5,nA ,M,1 cm,2 and detection limit of 4.2,,M. The apparent Michaelis-Menten constant and the response time of the biosensor are 0.49,mM and 15,s, respectively. This biosensor also exhibits good stability, reproducibility and long life time. [source] Lactate Biosensor Based on Hydrotalcite-Like Compounds: Performances and Application to Serum SamplesELECTROANALYSIS, Issue 22 2009Irene Carpani Abstract A lactate biosensor based on lactate oxidase supported onto a hydrotalcite, electrochemically deposited on a platinum surface, was developed for the first time. For the best electrode configuration, a linear response up to 0.8,mM, with a limit of detection of 14,,M and a sensitivity of 91,mA M,1,cm,2, was obtained. The influence of some interferents due to the oxidation of hydrogen peroxide (at +0.35,V vs. SCE) was also studied. By controlling carefully the experimental conditions, the determination of lactate in a commercial serum sample in the presence of interferents was successfully accomplished. [source] Glucosinolate Amperometric Bienzyme Biosensor Based on Carbon Nanotubes-Gold Nanoparticles Composite ElectrodesELECTROANALYSIS, Issue 13 2009V. Serafín Abstract A novel electrochemical biosensor design for glucosinolate determination involving bulk-incorporation of the enzymes glucose oxidase and myrosinase into a colloidal gold - multiwalled carbon nanotubes composite electrode using Teflon as binder is reported. Myrosinase catalyzes the hydrolysis of glucosinolate forming glucose, which is enzymatically oxidized. The generated hydrogen peroxide was electrochemically detected without mediator at the nanostructured composite electrode at E=+0.5,V vs. Ag/AgCl. Under the optimized conditions, the bienzyme MYR/GOx-Aucoll -MWCNT-Teflon exhibited improved analytical characteristics for the glucosinolate sinigrin with respect to a biosensor constructed without gold nanoparticles, i.e. a MYR/GOx-MWCNT-Teflon electrode, as well as with respect to other glucosinolate biosensor designs reported in the literature. The biosensor exhibits good repeatability of the amperometric measurements and good interassay reproducibility. Furthermore, the biosensor exhibited a high selectivity with respect to various potential interferents. The usefulness of the biosensor was evaluated by the determination of glucosinolate in Brussel sprout seeds. [source] Reagentless Biosensor for Hydrogen Peroxide Based on the Immobilization of Hemoglobin in Platinum Nanoparticles Enhanced Poly(chloromethyl thiirane) Cross-linked Chitosan Hybrid FilmELECTROANALYSIS, Issue 12 2009Shanshan Jia Abstract An unmediated hydrogen peroxide (H2O2) biosensor was prepared by co-immobilizing hemoglobin (Hb) with platinum nanoparticles enhanced poly(chloromethyl thiirane) cross-linked chitosan (CCCS-PNs) hybrid film. CCCS could provide a biocompatible microenvironment for Hb and PNs could accelerate the electron transfer between Hb and the electrode. Spectroscopic analysis indicated that the immobilized Hb could maintain its native structure in the CCCS-PNs hybrid film. Entrapped Hb exhibited direct electrochemistry for its heme Fe(III)/Fe(II) redox couples at ,0.396,V in the CCCS-PNs hybrid film, as well as peroxidase-like activity to the reduction of hydrogen peroxide without the aid of an electron mediator. [source] An Organic Sol-Gel Film as Modifier to Construct BiosensorELECTROANALYSIS, Issue 2 2009Jian-Feng Wu Abstract A new amperometric biosensor for hydrogen peroxide (H2O2) was developed by adsorbing hemoglobin (Hb) on an organic sol-gel film. The organic sol-gel was prepared using resorcinol and formaldehyde as monomers. This sol-gel film shows a biocompatible microenvironment for retaining the native activity of the adsorbed Hb. The direct electron transfer between Hb and electrode is achieved. Hb adsorbed on the film shows an enzyme-like catalytic activity for the reduction of H2O2. The reduction peak currents are proportional linearly to the concentration of hydrogen peroxide in the range of 6×10,8 to 3.6×10,6,M, with a detection limit of 2.4×10,8,M (S/N=3). This research enlarges the applications of organic sol-gel materials in biosensor field. [source] Gas Diffusion Electrodes for Use in an Amperometric Enzyme BiosensorELECTROANALYSIS, Issue 21 2008Martin Hämmerle Abstract The preparation of gas diffusion electrodes and their use in an amperometric enzyme biosensor for the direct detection of a gaseous analyte is described. The gas diffusion electrodes are prepared by covering a PTFE membrane (thickness 250,,m, pore size 2,,m, porosity 35%) with gold, platinum, or a graphite/PTFE mixture. Gold and platinum are deposited by e-beam sputtering, whereas the graphite/PTFE layer is prepared by vacuum filtration of a respective aqueous suspension. These gas diffusion electrodes are exemplarily implemented as working electrodes in an amperometric biosensor for gaseous formaldehyde containing NAD-dependent formaldehyde dehydrogenase from P. putida [EC. 1.2.1.46] as enzyme and 1,2-naphthoquinone-4-sulfonic acid as electrochemical mediator. The resulting sensors are compared with regard to background current, signal noise, linear range, sensitivity, and detection limit. In this respect, sensors with gold or graphite/PTFE covered membranes outclass ones with platinum for this particular analyte and sensor configuration. [source] Amperometric L -Lactate Biosensor Based on Gold NanoparticlesELECTROANALYSIS, Issue 7-8 2007Bikash, Kumar Jena Abstract A novel amperometric biosensor for the sensing of L -lactate is developed using L -lactate dehydrogenase (LDH) and hydroxylamine enlarged gold nanoparticles (GNPs). LDH and GNPs have been integrated with the sol,gel 3-D silicate network derived from 3-(mercaptopropyl)trimethoxysilane (MPTS). The biosensing of L -lactate is based on the electrocatalytic determination of enzymatically generated NADH by GNPs of the integrated assembly. The GNPs on the network efficiently catalyze the oxidation of NADH at ,0.065,V, which is ca. 915,mV less positive than on the bulk Au electrode. The biosensor was characterized in terms of the effects of enzyme loading, solution pH, and cofactor concentration. The integrated biosensor was successfully utilized for the amperometric sensing of L -lactate and it shows excellent sensitivity with a detection limit of 100,nM. The common interfering electroactive compounds in the biological system do not interfere the amperometric measurement of L -lactate. This biosensor linearly responds to L -lactate in the range of 0,0.8,mM and the sensitivity of the electrode was 0.446,nA/nM. Excellent reproducibility, long time storage and operational stability have been achieved. [source] Biosensor Based on Self-Assembling Glucose Oxidase and Dendrimer-Encapsulated Pt Nanoparticles on Carbon Nanotubes for Glucose DetectionELECTROANALYSIS, Issue 6 2007Lihuan Xu Abstract A novel amperometric glucose biosensor based on layer-by-layer (LbL) electrostatic adsorption of glucose oxidase (GOx) and dendrimer-encapsulated Pt nanoparticles (Pt-DENs) on multiwalled carbon nanotubes (CNTs) was described. Anionic GOx was immobilized on the negatively charged CNTs surface by alternatively assembling a cationic Pt-DENs layer and an anionic GOx layer. Transmission electron microscopy images and ,-potentials proved the formation of layer-by-layer nanostructures on carboxyl-functionalized CNTs. LbL technique provided a favorable microenvironment to keep the bioactivity of GOx and prevent enzyme molecule leakage. The excellent electrocatalytic activity of CNTs and Pt-DENs toward H2O2 and special three-dimensional structure of the enzyme electrode resulted in good characteristics such as a low detection limit of 2.5,,M, a wide linear range of 5,,M,0.65,mM, a short response time (within 5,s), and high sensitivity (30.64,,A mM,1,cm,2) and stability (80% remains after 30 days). [source] Glucose Biosensor Mediated by 1,2-Diferrocenylethane in a Sono-Gel Composite ElectrodeELECTROANALYSIS, Issue 2-3 2007Barbara Ballarin Abstract An amperometric glucose biosensor was constructed based on a renewable carbon composite sono-gel matrix incorporating 1,2-diferrocenylethane as electron transfer mediator between the electrode and the active site of glucose oxidase. The enzyme was immobilized on the electrode surface by cross-linking with glutaraldehyde and bovine serum albumin. The process parameters for the fabrication of the biosensor and the influence of various experimental conditions (i.e., pH, temperature, operating potential) were investigated. Cyclic voltammetry and amperometric measurements were used to study the response of the glucose sensor, which displayed fast response time and good reproducibility. The analytical performances and the apparent Michaelis-Menten constant of the biosensor were evaluated. [source] Development of Quantum Dots Modified Acetylcholinesterase Biosensor for the Detection of TrichlorfonELECTROANALYSIS, Issue 22 2006Xiao-Hua Li Abstract Poly (N -vinyl-2-pyrrolidone) (PVP)-capped CdS quantum dots (QCdS-PVP) was synthesized with CdCl2 and Na2S in the presence of PVP. QCdS-PVP has been used for the immobilization and stabilization of the acetylcholinesterase (AChE). The electrocatalytic activity of QCdS-PVP leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, and higher sensitivity and stability. The GCE/QCdS-PVP/AChE biosensor was used for the detection of organophosphate pesticides (OPs), such as trichlorfon. The sensor performance, including pH and inhibition time, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 12 ppb trichlorfon with a 5-min inhibition time. [source] Glutathione Peroxidase-Based Amperometric Biosensor for the Detection of S -NitrosothiolsELECTROANALYSIS, Issue 21 2006Mustafa Musameh Abstract A new biosensor is described for the detection of S -nitrosothiols (RSNOs) based on their decomposition by immobilized glutathione peroxidase (GPx), an enzyme containing selenocysteine residue that catalytically produces nitric oxide (NO) from RSNOs. The enzyme is entrapped at the distal tip of a planar amperometric NO sensor. The new biosensor shows good sensitivity, linearity, reversibility, and response times towards various RSNO species in PBS buffer, pH,7.4 . In most cases, the response time is less than 5,min, and the response is linear up to 6 ,M of the tested RSNO species. The lowest detection limit is obtained for S -nitrosocysteine (CysNO), at approx. 0.2,,M. The biosensor's sensitivity is not affected by the addition of EDTA as a chelating agent; an advantage over other potential catalytic enzymes that contain copper ion centers, such as CuZn-superoxide dismutase and xanthine oxidase. However, lifetime of the new sensor is limited, with sensitivity decrease of 50% after two days of use. Nonetheless, the new amperometric GPx based RSNO sensor could prove useful for detecting relative RSNO levels in biological samples, including whole blood. [source] Reagentless Glucose Biosensor Based on the Direct Electrochemistry of Glucose Oxidase on Carbon Nanotube-Modified ElectrodesELECTROANALYSIS, Issue 11 2006Xiliang Luo Abstract The direct electrochemistry of glucose oxidase (GOD) was revealed at a carbon nanotube (CNT)-modified glassy carbon electrode, where the enzyme was immobilized with a chitosan film containing gold nanoparticles. The immobilized GOD displays a pair of redox peaks in pH,7.4 phosphate buffer solutions (PBS) with the formal potential of about ,455,mV (vs. Ag/AgCl) and shows a surface-controlled electrode process. Bioactivity remains good, along with effective catalysis of the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, which could be used for reagentless detection of glucose with a linear range from 0.04 to 1.0,mM. The proposed glucose biosensor exhibited high sensitivity, good stability and reproducibility, and was also insensitive to common interferences such as ascorbic and uric acid. The excellent performance of the reagentless biosensor is attributed to the effective enhancement of electron transfer between enzyme and electrode surface by CNTs, and the biocompatible environment that the chitosan film containing gold nanoparticles provides for immobilized GOD. [source] Gold Nanoparticle-Based Mediatorless Biosensor Prepared on Microporous ElectrodeELECTROANALYSIS, Issue 3 2006Fenghua Zhang Abstract A mediatorless biosensor was fabricated with a double-sided microporous gold electrode by successively immobilizing a mixed self-assembled monolayer (SAM) comprising carboxylic-acid- and thiol-terminated thiolate (dl -thiorphan and 1,8-octanedithiol), glucose oxidase (GOx) and finally gold nanoparticle (Au NP) on one working side. The double-sided microporous gold electrodes were formed by plasma sputtering of gold on a porous nylon substrate, yielding a face-to-face type two-electrode electrochemical cell. While the straight chain molecule 1,8-octanedithiol forms a dense insulating monolayer, the side armed dl -thiorphan forms a low density layer for the diffusion of redox couples to the electrode surface. The mixed SAM not only provided the linking functional groups for both enzyme and Au NP but also resulted in the appropriately spaced monolayer for direct electron tansfer (ET) process from the center of the redox enzyme to the electrode surface. After covalently immobilizing GOx onto the carboxylic-acid-terminated monolayer, Au NP was easily immobilized to both enzyme and nearby thiols by simple dispensing of the colloidal gold solution. It was observed that the resulting amperometric biosensor exhibited quantitatively the same response to glucose in the presence and in the absence of dissolved oxygen, which evidence that the Au NPs immobilized on and around the GOx promote direct ET from the enzymes to the electrode, assuming the role of a common redox mediator. [source] Development of a Rapid Single-Drop Analysis Biosensor for Screening of Phenanthrene in Water SamplesELECTROANALYSIS, Issue 20 2004Abstract Detection techniques for biosensors often require bulky instruments or cells that are not feasible for in-field analysis. Our single-drop cell design, optimized in this work, comprised a screen-printed three-electrode (SPE), strip in horizontal position onto which a volume of 100,,L of sample or substrate solution was placed to ensure electrical contact (complete circuit). Together with optimized linear sweep voltammetry (LSV), parameters for the detection of the enzyme alkaline phosphatase (AP), the system was applied to a biosensor for the analysis of polycyclic aromatic hydrocarbons (PAHs), in environmental samples. A limit of detection (LOD), of 0.15,ppb was achieved for a model system with an IC50 value of 0.885 ppb and a linear range (LR), of 0.2,10,ppb. Application of the single drop analysis (SDA), format to a PAH biosensor gave a LOD of 1.4,ppb for detection of phenanthrene with an IC50 value of 29.3,ppb and linear range of 2,100,ppb. Proof of concept is shown with spiked sample analysis of phenanthrene in matrices such as sea, river and tap water. [source] Biosensor for Hepatitis B Virus DNA PCR Product and Electrochemical Study of the Interaction of Di(2,2,-bipyridine)osmium(III) with DNAELECTROANALYSIS, Issue 19 2004Hongtao Zhao Abstract The strategy for electrochemical detection of HBV DNA PCR product (181,bps) was designed by covalently immobilizing single-stranded HBV DNA on preoxidized glassy carbon electrode surface. The immobilization of single stranded DNA was verified by AC impedance spectra. The following hybridization reaction on surface was evidenced by electrochemical methods using [Os(bpy)2Cl2]+ as an electroactive indicator. The interactions of [Os(bpy)2Cl2]+ with calf thymus single and double stranded DNA immobilized on preoxidized glassy carbon electrodes were studied. [Os(bpy)2Cl2]+ could bind preferentially to the duplex DNA by intercalating to base pairs. The intrinsic binding constant of [Os(bpy)2Cl2]+ with calf thymus DNA was calculated to be 1.21×104,M,1. Using [Os(bpy)2Cl2]+ as an electrochemical hybridization indicator, the HBV DNA sensor has been used to detect qualitatively target HBV DNA in solution with high sensitivity and selectivity. [source] A Lactulose Bienzyme Biosensor Based on Self-Assembled Monolayer Modified ElectrodesELECTROANALYSIS, Issue 17 2004Susana Campuzano Abstract A bienzyme biosensor in which the enzymes ,-galactosidase (,-Gal), fructose dehydrogenase (FDH), and the mediator tetrathiafulvalene (TTF) were coimmobilized by cross-linking with glutaraldehyde atop a 3-mercaptopropionic acid (MPA) self-assembled monolayer on a gold disk electrode, is reported. The working conditions selected were Eapp=+0.10,V and (25±1),°C. The useful lifetime of one single TTF-,-Gal-FDH-MPA-AuE was surprisingly long, 81,days. A linear calibration plot was obtained for lactulose over the 3.0×10,5,1.0×10,3,mol L,1 concentration range, with a limit of detection of 9.6×10,6,mol L,1. The effect of potential interferents (lactose, glucose, galactose, sucrose, and ascorbic acid) on the biosensor response was evaluated. The behavior of the SAM-based biosensor in flow-injection systems in connection with amperometric detection was tested. The analytical usefulness of the biosensor was evaluated by determining lactulose in a pharmaceutical preparation containing a high lactulose concentration, and in different types of milk. Finally, the analytical characteristics of the TTF-,-Gal-FDH-MPA-AuE are critically compared with those reported for other recent enzymatic determinations of lactulose. [source] A New Polyphenol Oxidase Biosensor Mediated by Azure B in Laponite Clay MatrixELECTROANALYSIS, Issue 19 2003Dan Shan Abstract Amperometric biosensor based on the entrapment of polyphenol oxidase within a laponite clay coating and cross-linked by glutaraldehyde is described for catechol detection. Laponite provides a hydrophilic enzyme surrounding increasing the long term stability of the biosensor compared to the corresponding biosensors obtained by chemical cross-linking of PPO with glutaraldehyde. Azure B, a cationic dye exchanged within the clay matrix, is used as an electron shuttle allowing the mediated detection of phenol derivatives at ,0.05 V. The detection limits obtained with the optimized biosensor configuration for catechol, p -cresol and phenol are 1, 1 and 17,nM, respectively. [source] A Microbial Biosensor for p -Nitrophenol Using Arthrobacter Sp.ELECTROANALYSIS, Issue 14 2003Yu Lei Abstract This article reports the construction, optimization of performance variables and analytical characterization of a sensitive and selective microbial amperometric biosensor for measurement of p -nitrophenol (PNP), a U.S. Environmental Agency priority pollutant. The biosensor consisted of PNP-degrading/oxidizing bacteria Arthrobacter sp. JS443 as biological sensing element and a dissolved oxygen electrode as the transducer. The best sensitivity and response time were obtained using a sensor constructed with 1.2,mg dry wt. of cells and operating in pH,7.5, 50,mM citrate-phosphate buffer. Using these conditions, the biosensor was able to measure as low as 28,ppb (0.2,,M) of PNP selectively without interference from structurally similar compounds, such as phenol, nitrophenols and chlorophenols. The service life of the microbial biosensor is around 5,days when stored in the operating buffer at 4,°C. The applicability to lake water is demonstrated. [source] Organically Modified Sol-Gel/Chitosan Composite Based Glucose BiosensorELECTROANALYSIS, Issue 7 2003Xu Chen Abstract A new type of organically modified sol-gel/chitosan composite material was developed and used for the construction of glucose biosensor. This material provided good biocompatibility and the stabilizing microenvironment around the enzyme. Ferrocene was immobilized on the surface of glassy carbon electrode as a mediator. The characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. The effects of enzyme-loading, buffer pH, applied potential and several interferences on the response of the enzyme electrode were investigated. The simple and low-cost glucose biosensor exhibited high sensitivity and good stability. [source] Electrochemical Biosensor for the Detection of Interaction Between Arsenic Trioxide and DNA Based on Guanine SignalELECTROANALYSIS, Issue 7 2003Mehmet Ozsoz Abstract The interaction of arsenic trioxide (As2O3) with calf thymus double-stranded DNA (dsDNA), calf thymus single-stranded DNA (ssDNA) and also 17-mer short oligonucleotide (Probe,A) was studied electrochemically by using differential pulse voltammetry (DPV) with carbon paste electrode (CPE) at the surface and also in solution. Potentiometric stripping analysis (PSA) was employed to monitor the interaction of As2O3 with dsDNA in solution phase by using a renewable pencil graphite electrode (PGE). The changes in the experimental parameters such as the concentration of As2O3, and the accumulation time of As2O3 were studied by using DPV; in addition, the reproducibility data for the interaction between DNA and As2O3 was determined by using both electrochemical techniques. After the interaction of As2O3 with dsDNA, the DPV signal of guanine was found to be decreasing when the accumulation time and the concentration of As2O3 were increased. Similar DPV results were also found with ssDNA and oligonucleotide. PSA results observed at a low DNA concentration such as 1,ppm and a different working electrode such as PGE showed that there could be damage to guanine bases. The partition coefficients of As2O3 after interaction with dsDNA and ssDNA in solution by using CPE were calculated. Similarly, the partition coefficients (PC) of As2O3 after interaction with dsDNA in solution was also calculated by PSA at PGE. The features of this proposed method for the detection of DNA damage by As2O3 are discussed and compared with those methods previously reported for the other type of DNA targeted agents in the literature. [source] Schottky-Gated Probe-Free ZnO Nanowire BiosensorADVANCED MATERIALS, Issue 48 2009Ping-Hung Yeh A nanowire-based nanosensor for detecting biologically and chemically charged molecules that is probe-free and highly sensitive is demonstrated. The device relies on the nonsymmetrical Schottky contact under reverse bias (see figure), and is much more sensitive than the device based on the symmetric ohmic contact. This approach serves as a guideline for designing more practical chemical and biochemical sensors. [source] A Cationic Water-Soluble Poly(p -phenylenevinylene) Derivative: Highly Sensitive Biosensor for Iron-Sulfur Protein Detection,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 10 2006Fan Cheng Abstract Summary: A new water-soluble cationic ammonium-functionalized poly(p -phenylenevinylene) (PPV-NEtMe) was successfully synthesized and exhibited high sensitivity (Ksv,=,6.9,×,107M,1) on rubredoxin, a type of anionic iron-sulfur (Fe-S) proteins. Further investigation showed that the biosensitivity of the cationic conjugated polymer is strongly dependent on the nature of the buffer solution and the concentration of the conjugated polymer used in the analyses. The schematic diagram of anionic rubredoxin detected by PPV-NEtMe. [source] Integration of a Fluorescent Molecular Biosensor into Self-Assembled Protein Nanowires: A Large Sensitivity Enhancement,ANGEWANDTE CHEMIE, Issue 40 2010Yan Leng Auf Draht: Das aus dem pH-empfindlichen grün fluoreszierenden Protein E2GFP, dem Enzym Methylparathion-Hydrolase (MPH) und dem Hefe-Prionenprotein Sup351-61 bestehende Hybrid Sup351-61 -E2GFP-MPH wurde durch Genfusion erhalten. Durch Aggregation der Sup351-61 -Untereinheiten entstand ein selbstorganisierter Nanodraht (siehe Bild). Der Draht kann als Biosensor Methylparathion mit 10,000fach größerer Empfindlichkeit detektieren als freies E2GFP-MPH. [source] Biosensor detects few hundred mycoplasma cells in cell cultureBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2010Article first published online: 24 FEB 2010 No abstract is available for this article. [source] Biotec Visions 2010, May,JuneBIOTECHNOLOGY JOURNAL, Issue 5 2010Article first published online: 3 MAY 2010 News:Ethanol biofuels from orange peels , Targeting leukaemia's gene addiction , Pea-derived solar cells , HIV is a kick in the head , Nano-scale DNA reader , Membrane in black , Cheese improves the immune response of elderly , Synthetic proteins built from standard parts , Therapeutic proteins produced in algae , Biosensor detects 100 mycoplasma cells , Protecting maggots against bacteria , Advanced biofuels from microbes , Fluorescent bacterial uptake , Two disparate stem cell states , Brachypodium genome sequenced Encyclopedia of Life Sciences: Nuclear transfer for cell lines WIREs Nanomedicine and Nanobiotechnology: Nanoparticle detection of respiratory infection Journal Highlights: Biocatalysis , Synthetic Biology In the news: Nanobiotech to detect cancer Most Read Industry News: Biomarker assays for personalized medicine , Bioplastic industry defies economic crisis , SDS-PAGE monitoring of mAB Awards: BTJ Editors elected members of the US National Academy of Engineering (NAE) Meeting highlight Writing tips: Figure preparation made simple , Some useful tutorials on the web Book Highlights:Molecular Biotechnology , Bacterial Signaling , Yeast Test your knowledge:Do you recognize this? WIREs Authors Spotlight:Nanotechnology and orthopedics [source] An RNase H-Assisted Fluorescent Biosensor for AptamersCHEMBIOCHEM, Issue 12 2007Dae-Ro Ahn Dr. Recycling program. A signal amplification strategy was established for aptamer-based molecular recognition of thrombin with concomitant release of a single-stranded guard-DNA (g-DNA). The g-DNA then bound to F-RNA-Q, which contained a fluorophore and quencher. The fluorescence-quenched RNA was degraded by using RNase H to give a fluorescence signal, and the undamaged g-DNA was recycled to yield fluorescence amplification. [source] Catalysis and Rational Engineering of trans-Acting pH6DZ1, an RNA-Cleaving and Fluorescence-Signaling Deoxyribozyme with a Four-Way Junction StructureCHEMBIOCHEM, Issue 9 2006Yutu Shen Biosensor made of a catalytic DNA. When the RNA moiety (red) in the fluorogenic DNA substrate (purple) is cleaved by the bound catalytic DNA (blue) with a multiduplex structure, a strong fluorescence signal is generated owing to the separation of the fluorophore (F) from the quencher (Q). [source] Luminescent Saccharide Biosensor by Using Lanthanide-Bound Lectin Labeled with FluoresceinCHEMBIOCHEM, Issue 8 2005Yoichiro Koshi A new luminescent biosensor for complicated glycoconjugates was engineered on the basis of a lanthanide-complexed sugar-binding protein (lectin) modified with a fluorophore. By using luminescence resonance energy transfer (LRET), ratiometric luminescent sensing can be carried out and successfully applied to a luminescent assay for an enzymatic trimming of a glycoprotein (see scheme). [source] | ||||||||||||||||||||||||||||||||||||||||