The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Joseph Wang - One of the best experts on this subject based on the ideXlab platform.

  • Potentiometric Detection of DNA Hybridization
    Journal of the American Chemical Society, 2007
    Co-Authors: Apon Numnuam, Joseph Wang, Karin Y. Chumbimuni-torres, Yun Xiang, R. Bash, Panote Thavarungkul, Proespichaya Kanatharana, Ernö Pretsch, Eric Bakker
    Abstract:

    The use of potentiometric microsensors is demonstrated here for the first time to detect DNA Hybridization. Cadmium sulfide nanocrystal labels bound on a secondary oligonucleotide are dissolved and detected with cadmium-selective microelectrodes exhibiting DNA detection limits of ca. 2 fmol in a 200 μL sample.

  • carbon nanotube modified glassy carbon electrodes for amplified label free electrochemical detection of DNA Hybridization
    Analyst, 2003
    Co-Authors: Joseph Wang, Abdel-nasser Kawde, Mustafa Musameh
    Abstract:

    The preparation and attractive performance of carbon-nanotube modified glassy-carbon (CNT/GC) electrodes for improved detection of purines, nucleic acids, and DNA Hybridization are described. The surface-confined multiwall carbon-nanotube (MWCNT) facilitates the adsorptive accumulation of the guanine nucleobase and greatly enhances its oxidation signal. The advantages of CNT/GC electrodes are illustrated from comparison to the common unmodified glassy carbon, carbon paste and graphite pencil electrodes. The dramatic amplification of the guanine signal has been combined with a label-free electrical detection of DNA Hybridization. Factors influencing the enhancement of the guanine signal are assessed and optimized. The performance characteristics of the amplified label-free electrochemical detection of DNA Hybridization are reported in connection to measurements of nucleic-acid segments related to the breast-cancer BRCA1 gene.

  • Genomagnetic electrochemical assays of DNA Hybridization
    Talanta, 2002
    Co-Authors: Joseph Wang, Danke Xu, Arzum Erdem, Ronen Polsky, Marcos A Salazar
    Abstract:

    Abstract An electrochemical genomagnetic Hybridization assay has been developed to take advantage of a new and efficient magnetic separation/mixing process, the amplification feature of enzyme labels, and single-use thick-film carbon transducers operated in the pulse-voltammetric mode. It represents the first example of coupling a magnetic isolation with electrochemical detection of DNA Hybridization. The new protocol employs an enzyme-linked sandwich solution Hybridization, with a magnetic-particle labeled probe hybridizing to a biotinylated DNA target that captures a streptavidin-alkaline phosphatase (AP). The α-naphthol product of the enzymatic reaction is quantitated through its well-defined, low-potential (+0.1 V vs. Ag/AgCl) differential pulse-voltammetric peak at the disposable screen-printed electrode. The efficient magnetic isolation is particularly attractive for electrical detection of DNA Hybridization which is commonly affected by the presence of non-hybridized nucleic acid adsorbates. The new biomagnetic processing combines such magnetic separation with a low-volume magnetic mixing, and allows simultaneous handling of 12 samples. The attractive bioanalytical behavior of the new enzyme-linked genomagnetic electrical assay is illustrated for the detection of DNA segments related to the breast-cancer BRCA1 gene.

  • Amplified label-free electrical detection of DNA Hybridization
    Analyst, 2002
    Co-Authors: Joseph Wang, Abdel-nasser Kawde
    Abstract:

    A new protocol is described for amplifying label-free electrochemical measurements of DNA Hybridization based on the enhanced accumulation of purine nucleobases in the presence of copper ions . Such electrical DNA assays involve Hybridization of the target to inosine-substituted oligonucleotide probes (captured on magnetic beads), acidic dipurinization of the hybrid DNA, and adsorptive chronopotentiometric stripping measurements of the free nucleobases in the presence of copper ions. Both amplified adenine and guanine peaks can be used for detecting the DNA Hybridization. The dramatic signal amplification advantage of this type of detection has been combined with efficient magnetic removal of non-complementary DNA, use of microliter sample volumes and disposable transducers. Factors influencing the signal enhancement were assessed and optimized. A detection limit of 40 fmol (250 pg) was obtained with 10 min Hybridization and 5 min adsorptive-accumulation times. The advantages of this procedure were demonstrated by its application in the detection of DNA segments related to the BRCA1 breast cancer gene. The copper enhancement holds great promise not only for the detection of DNA Hybridization, but also for trace measurement of nucleic acids.

  • silver enhanced colloidal gold electrochemical stripping detection of DNA Hybridization
    Langmuir, 2001
    Co-Authors: Joseph Wang, And Ronen Polsky, Danke Xu
    Abstract:

    We report on a novel method for detecting DNA Hybridization, based on the precipitation of silver on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved silver. Such coupling of a nanoparticle-promoted silver precipitation with the remarkable sensitivity of stripping metal analysis offers a dramatic enhancement of the Hybridization response. An efficient magnetic isolation of the duplex is used for discriminating against nonhybridized DNA, including an excess of mismatched oligonucleotides. The new silver-enhanced colloidal gold stripping detection strategy holds great promise for the detection of DNA Hybridization and represents an attractive alternative to indirect optical affinity assays of nucleic acids and other biomolecules.

Danke Xu - One of the best experts on this subject based on the ideXlab platform.

  • Genomagnetic electrochemical assays of DNA Hybridization
    Talanta, 2002
    Co-Authors: Joseph Wang, Danke Xu, Arzum Erdem, Ronen Polsky, Marcos A Salazar
    Abstract:

    Abstract An electrochemical genomagnetic Hybridization assay has been developed to take advantage of a new and efficient magnetic separation/mixing process, the amplification feature of enzyme labels, and single-use thick-film carbon transducers operated in the pulse-voltammetric mode. It represents the first example of coupling a magnetic isolation with electrochemical detection of DNA Hybridization. The new protocol employs an enzyme-linked sandwich solution Hybridization, with a magnetic-particle labeled probe hybridizing to a biotinylated DNA target that captures a streptavidin-alkaline phosphatase (AP). The α-naphthol product of the enzymatic reaction is quantitated through its well-defined, low-potential (+0.1 V vs. Ag/AgCl) differential pulse-voltammetric peak at the disposable screen-printed electrode. The efficient magnetic isolation is particularly attractive for electrical detection of DNA Hybridization which is commonly affected by the presence of non-hybridized nucleic acid adsorbates. The new biomagnetic processing combines such magnetic separation with a low-volume magnetic mixing, and allows simultaneous handling of 12 samples. The attractive bioanalytical behavior of the new enzyme-linked genomagnetic electrical assay is illustrated for the detection of DNA segments related to the breast-cancer BRCA1 gene.

  • silver enhanced colloidal gold electrochemical stripping detection of DNA Hybridization
    Langmuir, 2001
    Co-Authors: Joseph Wang, And Ronen Polsky, Danke Xu
    Abstract:

    We report on a novel method for detecting DNA Hybridization, based on the precipitation of silver on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved silver. Such coupling of a nanoparticle-promoted silver precipitation with the remarkable sensitivity of stripping metal analysis offers a dramatic enhancement of the Hybridization response. An efficient magnetic isolation of the duplex is used for discriminating against nonhybridized DNA, including an excess of mismatched oligonucleotides. The new silver-enhanced colloidal gold stripping detection strategy holds great promise for the detection of DNA Hybridization and represents an attractive alternative to indirect optical affinity assays of nucleic acids and other biomolecules.

  • Silver-enhanced colloidal gold electrochemical stripping detection of DNA Hybridization
    Langmuir, 2001
    Co-Authors: Joseph Wang, Ronen Polsky, Danke Xu
    Abstract:

    We report on a novel method for detecting DNA Hybridization, based on the precipitation of silver on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved silver. Such coupling of a nanoparticle-promoted silver precipitation with the remarkable sensitivity of stripping metal analysis offers a dramatic enhancement of the Hybridization response. An efficient magnetic isolation of the duplex is used for discriminating against nonhybridized DNA, including an excess of mismatched oligonucleotides. The new silver-enhanced colloidal gold stripping detection strategy holds great promise for the detection of DNA Hybridization and represents an attractive alternative to indirect optical affinity assays of nucleic acids and other biomolecules.\nWe report on a novel method for detecting DNA Hybridization, based on the precipitation of silver on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved silver. Such coupling of a nanoparticle-promoted silver precipitation with the remarkable sensitivity of stripping metal analysis offers a dramatic enhancement of the Hybridization response. An efficient magnetic isolation of the duplex is used for discriminating against nonhybridized DNA, including an excess of mismatched oligonucleotides. The new silver-enhanced colloidal gold stripping detection strategy holds great promise for the detection of DNA Hybridization and represents an attractive alternative to indirect optical affinity assays of nucleic acids and other biomolecules.

John H. Reif - One of the best experts on this subject based on the ideXlab platform.

  • localized DNA Hybridization chain reactions on DNA origami
    ACS Nano, 2018
    Co-Authors: Shalin Shah, Sudhanshu Garg, Reem Mokhtar, Tianqi Song, John H. Reif
    Abstract:

    The field of DNA nanoscience has demonstrated many exquisite DNA nanostructures and intricate DNA nanodevices. However, the operation of each step of prior demonstrated DNA nanodevices requires the diffusion of DNA strands, and the speed of these devices is limited by diffusion kinetics. Here we demonstrate chains of localized DNA Hybridization reactions on the surface of a self-assembled DNA origami rectangle. The localization design for our DNA nanodevices does not rely on the diffusion of DNA strands for each step, thus providing faster reaction kinetics. The locality also provides considerable increased scalability, since localized components of the devices can be reused in other locations. A variety of techniques, including atomic force microscopy, total internal reflection fluorescence, and ensemble fluorescence spectroscopy, are used to confirm the occurrence of localized DNA Hybridization reactions on the surface of DNA origami. There are many potential biological applications for our localized DN...

  • Design and Analysis of Localized DNA Hybridization Chain Reactions.
    Small, 2017
    Co-Authors: Vincent Miao, Sudhanshu Garg, Reem Mokhtar, Tianqi Song, John H. Reif
    Abstract:

    Theoretical models of localized DNA Hybridization reactions on nanoscale substrates indicate potential benefits over conventional DNA Hybridization reactions. Recently, a few approaches have been proposed to speed-up DNA Hybridization reactions; however, experimental confirmation and quantification of the acceleration factor have been lacking. Here, a system to investigate localized DNA Hybridization reactions on a nanoscale substrate is presented. The system consists of six metastable DNA hairpins that are tethered to a long DNA track. The localized DNA Hybridization reaction of the proposed system is triggered by a DNA strand which initiates the subsequent self-assembly. Fluorescence kinetics indicates that the half-time completion of a localized DNA Hybridization chain reaction is six times faster than the same reaction in the absence of the substrate. The proposed system provides one of the first known quantification of the speed-up of DNA Hybridization reactions due to the locality effect.

Rohit Chand - One of the best experts on this subject based on the ideXlab platform.

  • NEMS - Flexible pentacene thin film transistors as DNA Hybridization sensor
    2011 6th IEEE International Conference on Nano Micro Engineered and Molecular Systems, 2011
    Co-Authors: Rohit Chand
    Abstract:

    A DNA Hybridization sensor using pentacene thin film transistors (TFTs) is an excellent candidate for disposable sensor applications due to their low-cost fabrication process and fast detection. We fabricated pentacene TFTs on flexible substrate for the sensing of DNA Hybridization. The 100 mer ss-DNA (poly A/poly T) or 100 bp ds-DNA (poly A/poly T hybrid) are deposited from a solution on pentacene layer. The electrical characteristics of devices were studied as a function of DNA immobilization, single- and double-strand DNA and DNA concentrations. The DNA molecules were immobilized directly on the surface of the pentacene, thereby producing a dramatic change in the electrical properties of the devices. Based on these results, we propose that a “label-free” detection technique for DNA Hybridization is possible through direct measurement of electrical properties by the immobilization of DNA on pentacene TFTs.

  • Flexible pentacene thin film transistors as DNA Hybridization sensor
    2011 6th IEEE International Conference on Nano Micro Engineered and Molecular Systems, 2011
    Co-Authors: Rohit Chand
    Abstract:

    A DNA Hybridization sensor using pentacene thin film transistors (TFTs) is an excellent candidate for disposable sensor applications due to their low-cost fabrication process and fast detection. We fabricated pentacene TFTs on flexible substrate for the sensing of DNA Hybridization. The 100 mer ss-DNA (poly A/poly T) or 100 bp ds-DNA (poly A/poly T hybrid) are deposited from a solution on pentacene layer. The electrical characteristics of devices were studied as a function of DNA immobilization, single- and double-strand DNA and DNA concentrations. The DNA molecules were immobilized directly on the surface of the pentacene, thereby producing a dramatic change in the electrical properties of the devices. Based on these results, we propose that a “label-free” detection technique for DNA Hybridization is possible through direct measurement of electrical properties by the immobilization of DNA on pentacene TFTs.

  • DNA Hybridization sensor based on pentacene thin film transistor
    Biosensors and Bioelectronics, 2010
    Co-Authors: Rohit Chand
    Abstract:

    Abstract A DNA Hybridization sensor using pentacene thin film transistors (TFTs) is an excellent candidate for disposable sensor applications due to their low-cost fabrication process and fast detection. We fabricated pentacene TFTs on glass substrate for the sensing of DNA Hybridization. The ss-DNA (polyA/polyT) or ds-DNA (polyA/polyT hybrid) were immobilized directly on the surface of the pentacene, producing a dramatic change in the electrical properties of the devices. The electrical characteristics of devices were studied as a function of DNA immobilization, single-stranded vs. double-stranded DNA, DNA length and concentration. The TFT device was further tested for detection of λ-phage genomic DNA using probe Hybridization. Based on these results, we propose that a “label-free” detection technique for DNA Hybridization is possible through direct measurement of electrical properties of DNA-immobilized pentacene TFTs.

Dongqing Li - One of the best experts on this subject based on the ideXlab platform.

  • Electrokinetically-controlled RNA-DNA Hybridization assay for foodborne pathogens
    Mikrochimica Acta, 2012
    Co-Authors: Xuan Weng, Hai Jiang, Dongqing Li
    Abstract:

    We have developed a microfluidic chip for use in an RNA-DNA Hybridization assay for foodborne pathogens. Automatic sequential reagent dispensing and washing was realized with a programmable DC voltage sequencer. Signal detection was achieved with a miniaturized optical detection module. Salmonella and Listeria monocytogenes bacteria in different concentrations were quantitatively determined by this RNA-DNA Hybridization assay in the microfluidic chip. The detection limit for the Salmonella and Listeria monocytogenes bacteria is 103 to 104 CFU mL−1. The method excels by a significant reduction in the consumption of sample and reagent, and a short assay time. This automatic-operating microfluidic RNA-DNA Hybridization assay is promising for on-site pathogen detection.

  • Microfluidic DNA Hybridization assays
    Microfluidics and Nanofluidics, 2011
    Co-Authors: Xuan Weng, Hai Jiang, Dongqing Li
    Abstract:

    DNA Hybridization is one of the most powerful techniques applied in diagnostic assays. Microfluidics provides a promising means to analyse small sample volumes, reduce reagent consumption and cost, shorten processing time as well as develop fast, sensitive and portable diagnostic tools. By coupling with the microfluidic technology, DNA Hybridization assay can achieve high sensitivity, enhance Hybridization kinetics and decrease the non-specific target-probe binding. The microfluidic-based DNA Hybridization technology has a great potential for developing low-cost, rapid, automatic and point-of-care diagnostic devices. In this article, we provide an overview and summarize the recent advances on the merging of microfluidics to DNA Hybridization assays. The advantages and disadvantages of various methods are discussed. Potential improvements required for these technologies are proposed as well.