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Marc J Madou - One of the best experts on this subject based on the ideXlab platform.

  • anomalous mixing behaviour in rotationally actuated microfluidic devices
    Lab on a Chip, 2011
    Co-Authors: Debapriya Chakraborty, Marc J Madou, Suman Chakraborty
    Abstract:

    We analyse the characteristics of two-fluid mixing in T-shaped microchannels on rotating platforms (Lab-on-a-Compact-Disk framework). Three regimes of mixing were identified based on the distinct flow behaviour in each of these regimes. A diffusion-based mixing regime was obtained for low rotation speeds. A Coriolis force based mixing regime was observed for intermediate rotation speeds, which introduced some nontrivial aspects in the mixing behaviour, which was explained through scaling analysis. At very high rotational speeds, rapid mixing close to the junction was achieved by exploiting flow instabilities (instability based mixing). A good agreement between the theoretical calculations and the experimental observations was obtained.

  • the integration of 3d carbon electrode dielectrophoresis on a cd like centrifugal microfluidic platform
    Lab on a Chip, 2010
    Co-Authors: Rodrigo Martinezduarte, Robert Gorkin, Kameel Abisamra, Marc J Madou
    Abstract:

    We introduce the integration of a novel dielectrophoresis (DEP)-assisted filter with a Compact Disk (CD)-based centrifugal platform. Carbon-electrode dielectrophoresis (carbon-DEP) refers to the use of carbon electrodes to induce DEP. In this work, 3D carbon electrodes are fabricated using the C-MEMS technique and are used to implement a DEP-enabled active filter to trap particles of interest. Compared to traditional planar metal electrodes, 3D carbon electrodes allow for superior filtering efficiency. The system includes mounting modular 3D carbon-DEP chips on an electrically interfaced rotating Disk. This allows simple centrifugal pumping to replace the large footprint syringe pump approaches commonly used in DEP systems. The advantages of the CD setup include not only a reduced footprint, but also complexity and cost reduction by eliminating expensive precision pumps and fluidic interconnects. To demonstrate the viability of this system we quantified the filter efficiency in the DEP trapping of yeast cells from a mix of latex and yeast cells. Results demonstrate selective filtering at flow rates up to 35 µl min−1. The impact of electrode height, DEP chip misalignment and particle sedimentation on filter efficiency and the advantages this system represents are analyzed. The ultimate goal is to obtain an automated platform for bioparticle sorting with application in different fields such as point-of-care diagnostics and cell-based therapies.

  • a novel Compact Disk like centrifugal microfluidics system for cell lysis and sample homogenization
    Colloids and Surfaces B: Biointerfaces, 2007
    Co-Authors: Horacio Kido, Miodrag Micic, Jim Norto, Jim Zoval, Marc J Madou
    Abstract:

    In this paper, we present the design and characterization of a novel platform for mechanical cell lysis of even the most difficult to lyse cell types on a micro or nanoscale (maximum 70L total volume). The system incorporates a machined plastic circular Disk assembly, magnetic field actuated microfluidics, centrifugal cells and tissue homogenizer and centrifugation system. The mechanism of tissue disruption of this novel cell homogenization apparatus derives from the relative motion of ferromagnetic metal Disks and grinding matrices in a liquid medium within individual chambers of the Disk in the presence of an oscillating magnetic field. The oscillation of the ferromagnetic Disks or blades produces mechanical impaction and shear forces capable of disrupting cells within the chamber both by direct action of the blade and by the motion of the surrounding lysis matrix, and by motion induced vortexing of buffer fluid. Glass beads or other grinding media are integrated into each lysis chamber within the Disk to enhance the transfer of energy from the oscillating metal blade to the cells. The system also achieves the centrifugal elimination of solids from each liquid sample and allows the elution of clarified supernatants via siphoning into a collection chamber fabricated into the plastic Disk assembly. This article describes system design, implementation and validation of proof of concept on two samples—Escherichia coli and Saccharomyces cerevisiae representing model systems for cells that are easy and difficult to lyse, respectively. © 2007 Elsevier B.V. All rights reserved.

  • a novel Compact Disk like centrifugal microfluidics system for cell lysis and sample homogenization
    Colloids and Surfaces B: Biointerfaces, 2007
    Co-Authors: Horacio Kido, Miodrag Micic, Jim Zoval, David M Smith, Jim Norton, Marc J Madou
    Abstract:

    In this paper, we present the design and characterization of a novel platform for mechanical cell lysis of even the most difficult to lyse cell types on a micro or nanoscale (maximum 70 microL total volume). The system incorporates a machined plastic circular Disk assembly, magnetic field actuated microfluidics, centrifugal cells and tissue homogenizer and centrifugation system. The mechanism of tissue disruption of this novel cell homogenization apparatus derives from the relative motion of ferromagnetic metal Disks and grinding matrices in a liquid medium within individual chambers of the Disk in the presence of an oscillating magnetic field. The oscillation of the ferromagnetic Disks or blades produces mechanical impaction and shear forces capable of disrupting cells within the chamber both by direct action of the blade and by the motion of the surrounding lysis matrix, and by motion induced vortexing of buffer fluid. Glass beads or other grinding media are integrated into each lysis chamber within the Disk to enhance the transfer of energy from the oscillating metal blade to the cells. The system also achieves the centrifugal elimination of solids from each liquid sample and allows the elution of clarified supernatants via siphoning into a collection chamber fabricated into the plastic Disk assembly. This article describes system design, implementation and validation of proof of concept on two samples--Escherichia coli and Saccharomyces cerevisiae representing model systems for cells that are easy and difficult to lyse, respectively.

  • Design of a Compact Disk-like Microfluidic Platform for Enzyme-Linked Immunosorbent Assay
    Analytical Chemistry, 2004
    Co-Authors: Siyi Lai, Shengnian Wang, L. James Lee, Jun Luo, Marc J Madou
    Abstract:

    This paper presents an integrated microfluidic device on a Compact Disk (CD) that performs an enzyme-linked immunosorbent assay (ELISA) for rat IgG from a hybridoma cell culture. Centrifugal and capillary forces were used to control the flow sequence of different solutions involved in the ELISA process. The microfluidic device was fabricated on a plastic CD. Each step of the ELISA process was carried out automatically by controlling the rotation speed of the CD. The work on analysis of rat IgG from hybridoma culture showed that the microchip-based ELISA has the same detection range as the conventional method on the 96-well microtiter plate but has advantages such as less reagent consumption and shorter assay time over the conventional method.

E M Leitch - One of the best experts on this subject based on the ideXlab platform.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    Astrophysical Journal Supplement Series, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star-forming regions. Here, we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 kλ), allowing us to trace spatial scales from 10^2 to 10^4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t < 0.2 Myr) in Serpens. We make a first estimate of Disk masses using the flux at 50 kλ, where the contribution from the envelope should be negligible, assuming an unresolved Disk. The resulting Disk masses range from 0.04 M_☉ to 1.7 M_☉, with a mean of approximately 0.2 M_☉. Our high-resolution maps are also sensitive to binary or multiple sources with separations ≳ 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    arXiv: Astrophysics of Galaxies, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch, D P Marrone
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star forming regions. Here we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 klam), allowing us to trace spatial scales from 1e2 to 1e4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

G Duchene - One of the best experts on this subject based on the ideXlab platform.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    Astrophysical Journal Supplement Series, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star-forming regions. Here, we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 kλ), allowing us to trace spatial scales from 10^2 to 10^4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t < 0.2 Myr) in Serpens. We make a first estimate of Disk masses using the flux at 50 kλ, where the contribution from the envelope should be negligible, assuming an unresolved Disk. The resulting Disk masses range from 0.04 M_☉ to 1.7 M_☉, with a mean of approximately 0.2 M_☉. Our high-resolution maps are also sensitive to binary or multiple sources with separations ≳ 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    arXiv: Astrophysics of Galaxies, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch, D P Marrone
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star forming regions. Here we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 klam), allowing us to trace spatial scales from 1e2 to 1e4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

Melissa L Enoch - One of the best experts on this subject based on the ideXlab platform.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    Astrophysical Journal Supplement Series, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star-forming regions. Here, we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 kλ), allowing us to trace spatial scales from 10^2 to 10^4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t < 0.2 Myr) in Serpens. We make a first estimate of Disk masses using the flux at 50 kλ, where the contribution from the envelope should be negligible, assuming an unresolved Disk. The resulting Disk masses range from 0.04 M_☉ to 1.7 M_☉, with a mean of approximately 0.2 M_☉. Our high-resolution maps are also sensitive to binary or multiple sources with separations ≳ 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

  • Disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the serpens sample
    arXiv: Astrophysics of Galaxies, 2011
    Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch, D P Marrone
    Abstract:

    We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize Disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star forming regions. Here we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 klam), allowing us to trace spatial scales from 1e2 to 1e4 AU. We find evidence for Compact Disk components in all of the observed Class 0 protostars, suggesting that Disks form at very early times (t 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.

Ángel Maquieira - One of the best experts on this subject based on the ideXlab platform.

  • Nanoparticle Bragg reflectors: A smart analytical tool for biosensing
    'Elsevier BV', 2019
    Co-Authors: Victoria González-pedro, Mauricio E. Calvo, Hernán Míguez, Ángel Maquieira
    Abstract:

    In this work, we present a novel optical biosensor based on periodically alternated layers of SiO2 and TiO2 nanoparticles grown by wet methods and working as a Bragg mirror in a label free format. The sensing principle relies on the change of the optical response generated by variations in the dielectric constant of the voids due to a biorecognition probe-target event. This change is reflected in a modification in the photonic band gap frequencies of the Bragg reflector. As a proof of concept, biotin and streptavidin biorecognition on the biosensor surface is monitored in label free format, achieving a LOD of 3.09 mg L−1 (54 nM) for the determination of streptavidin. Our proposed biosensor also shows selective determination against a variety of targets (horseradish peroxidase and bovine serum albumin antibody) working in physiological conditions (diluted human serum). To get a picture of the potential of our development and its ease of integration, we incorporated the immunosensor in an electronic consumable technology, such as Compact Disk, using the optical Disk as analytical platform and a CD player detector for the determination of streptavidin. Thus, our findings point out the feasibility of nanoparticle based Bragg reflectors in the biosensing field and open new avenues towards the rational design of a new generation of versatile, easy to fabricate in mass scale and cost-competitive biosensors

  • array on a Disk how blu ray technology can be applied to molecular diagnostics
    Expert Review of Molecular Diagnostics, 2014
    Co-Authors: Sergi Morais, Luis A Tortajadagenaro, Ángel Maquieira
    Abstract:

    This editorial comments on the balance and perspectives of Compact Disk technology applied to molecular diagnostics. The development of sensitive, rapid and multiplex assays using Blu-ray technology for the determination of biomarkers, drug allergens, pathogens and detection of infections would have a direct impact on diagnostics. Effective tests for use in clinical, environmental and food applications require versatile and low-cost platforms as well as cost-effective detectors. Blu-ray technology accomplishes those requirements and advances on the concept of high density arrays for massive screening to achieve the demands of point of care or in situ analysis.

  • Analytical prospect of Compact Disk technology in immunosensing.
    Analytical and bioanalytical chemistry, 2008
    Co-Authors: Sergi Morais, Rosa Puchades, Javier Carrascosa, Jesús Tamarit-lópez, Ángel Maquieira
    Abstract:

    A sensitive and versatile methodology involving recordable Compact Disks as molecular screening surfaces and a standard optical CD/DVD drive as detector, is reported. Quantitative immunoanalysis, in microarray format, of a cancer marker (alpha-fetoprotein, AFP) and a selective herbicide (atrazine) on four types of audio-video disc was conducted. Enzyme or gold nanoparticle-labeled antibodies were used as tracers, forming a precipitate on the sensing Disk surface. The principle of Disk reading is based on capture of analog signals with the Disk drive that were proportional to the darkness of the immunoreaction product. Detection limits for AFP (8.0 μg L−1) and for atrazine (0.04 μg L−1) were under the threshold needed to detect nonseminomatous testicular cancer, and below the maximum E.U. residue limit for drinking water, respectively. The described methodology improves the previous developments using CDs and highlights the enormous potential of immunoassay methods using standard audio–video Disk surfaces in combination with the CD/DVD drive for clinical analysis, drug discovery, or high-throughput multiresidue screening applications.