The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Pierluigi Reschiglian - One of the best experts on this subject based on the ideXlab platform.
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Field-Flow Fractionation and biotechnology.
Trends in biotechnology, 2005Co-Authors: Pierluigi Reschiglian, Andrea Zattoni, Barbara Roda, Elisa Michelini, Aldo RodaAbstract:The gentle separation mechanism has made Field-Flow Fractionation particularly suited to samples of biotechnological interest, from proteins and nucleic acids to viruses, subcellular units and whole cells. Recent progress in Field-Flow Fractionation technology, as well as the development of coupled techniques combining Field-Flow Fractionation capabilities with the specificity and sensitivity of well-established analytical methods, opens up new biotechnological applications for Field-Flow Fractionation. The most recent appealing applications include: sorting and fingerprinting of bacteria for whole-cell vaccine production; noninvasive and tagless sorting of immature and stem cells; separation of intact proteins and enzymes in top-down proteomics; and the development of Flow-assisted, multianalyte immunoassays using nano- and micron-sized particles with immobilized biomolecules.
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Field-Flow Fractionation of cells with chemiluminescence detection.
Journal of chromatography. A, 2004Co-Authors: Dora Melucci, Pierluigi Reschiglian, Andrea Zattoni, Barbara Roda, Sonia Casolari, Aldo RodaAbstract:Field-Flow Fractionation is a separation technique characterized by a retention mechanism which makes it suitable for sorting cells over a short analysis time, with low sample carry-over and preserving cell viability. Thanks to its high sensitivity, chemiluminescence detection is suitable for the quantification of just a few cells expressing chemiluminescence or bioluminescence. In this work, different formats for coupling gravitational Field-Flow Fractionation and chemiluminescence detection are explored to achieve ultra-sensitive cell detection in the framework of cell sorting. The study is carried out using human red blood cells as model sample. The best performance is obtained with the on-line coupling format, performed in post-column Flow-injection mode. Red cells are isolated from diluted whole human blood in just a few minutes and detected using the liquid phase chemiluminescent reaction of luminol catalysed by the red blood cell heme. The limit of detection is a few hundred injected cells. This is lower than the limit of detection usually achieved by means of conventional colorimetric/turbidimetric methods, and it corresponds to a red blood cell concentration in the injected sample of five orders of magnitude lower than in whole blood.
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Coupling gravitational and Flow Field-Flow Fractionation, and size-distribution analysis of whole yeast cells.
Analytical and bioanalytical chemistry, 2004Co-Authors: Ramsés Sanz, Pierluigi Reschiglian, Andrea Zattoni, Lluís Puignou, Maria Teresa Galceran, Dora MelucciAbstract:This work continues the project on Field-Flow Fractionation characterisation of whole wine-making yeast cells reported in previous papers. When yeast cells are fractionated by gravitational Field-Flow Fractionation and cell sizing of the collected fractions is achieved by the electrosensing zone technique (Coulter counter), it is shown that yeast cell retention depends on differences between physical indexes of yeast cells other than size. Scanning electron microscopy on collected fractions actually shows co-elution of yeast cells of different size and shape. Otherwise, the observed agreement between the particle size distribution analysis obtained by means of the Coulter counter and by Flow Field-Flow Fractionation, which employs a second mobile phase Flow as applied Field instead of Earth's gravity, indicates that yeast cell density can play a major role in the gravitational Field-Flow Fractionation retention mechanism of yeast cells, in which Flow Field-Flow Fractionation retention is independent of particle density. Flow Field-Flow Fractionation is then coupled off-line to gravitational Field-Flow Fractionation for more accurate characterisation of the doubly-fractionated cells. Coupling gravitational and Flow Field-Flow Fractionation eventually furnishes more information on the multipolydispersity indexes of yeast cells, in particular on their shape and density polydispersity.
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Flow Field‐Flow Fractionation with chemiluminescence detection for Flow‐assisted, multianalyte assays in heterogeneous phase
Journal of Separation Science, 2003Co-Authors: Pierluigi Reschiglian, Andrea Zattoni, Barbara Roda, Dora Melucci, Massimo Guardigli, Aldo RodaAbstract:On-line, continuous chemiluminescence detection has been recently applied to gravitational Field-Flow Fractionation as a new method suitable for Flow-assisted assays based on the separation between the analyte in solution and the analyte bound to micrometer-sized particles. In this work, Flow Field-Flow Fractionation coupled with off-line chemiluminescence detection is exploited for the development of Flow-assisted, multianalyte assays. Micrometer-sized, polystyrene beads coated with enzymes suitable for chemiluminescence detection, such as horseradish peroxidase and alkaline phosphatase, are used as model samples. The high size-based selectivity of Flow Field-Flow Fractionation and specificity of chemiluminescence detection make possible, in a single run with very short analysis time, the simultaneous, high sensitivity detection of the different enzymes linked to beads of different size.
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Working without accumulation membrane in Flow Field-Flow Fractionation.
Analytical chemistry, 2000Co-Authors: Pierluigi Reschiglian, Dora Melucci, And A. Zattoni, L. Malló, M. Hansen, And A. Kummerow, M. MillerAbstract:Nonideal interaction of sample with the separation device is a difficulty found in chromatographic methods as well as in Field-Flow Fractionation. However, in Field-Flow Fractionation (FFF), greater flexibility in the choice of carrier solution composition is possible, thus reducing the need of a wide choice of surface chemistry when nonideal sample interaction is to be minimized. The use of an ultrafiltration membrane as the surface for the accumulation wall is common practice in Flow Field-Flow Fractionation. Typical membranes in use are laminates of a skin membrane onto a backing material such as woven polyester. At this point, only a limited choice of membrane chemistries is available. Many membranes have been developed for protein applications as membranes are widely used in the pharmaceutical industries. While these membranes work well for protein applications, Flow Field-Flow Fractionation is applicable to polymeric particulate as well as protein samples. Thus, sample interaction with the membrane surface is possible with nonprotein applications and these interactions can induce significant secondary effects on retention ratio and affect instrumental reliability. Also, the woven texture of membranes may detrimentally affect the FFF separation. For these reasons, the study of Flow Field-Flow Fractionation using a flat, smooth surface of controlled chemistry is of relevance. We present here the results of a new, membraneless channel that uses a bare frit as the accumulation wall and that is intended for analysis of micrometer-sized particles only. Selectivity results are comparable to those obtained with the membrane, while relative sample recovery indicates that the best quantitative performance can be obtained without the membrane. Moreover, neither sample immobilization nor losses through the frit occur when operating membraneless. On the other hand, first experimental evidence of a certain level of frit surface activity suggests that optimization of experimental conditions is required.
Philippe J.p. Cardot - One of the best experts on this subject based on the ideXlab platform.
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Sedimentation Field-Flow Fractionation application to Toxoplasma gondii separation and purification.
Journal of pharmaceutical and biomedical analysis, 1999Co-Authors: Fawzi Bouamrane, N.emmanuel Assidjo, Bernard Bouteille, Marie F. Dreyfuss, Marie Laure Dardé, Philippe J.p. CardotAbstract:Abstract Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii , an intracellular protozoa of micronic size range (4–10 μm). Its classical purification processes are complex and often associated with low recovery. All investigation procedures concerning this parasite require its isolation and purification from at least the mouse ascitic fluid. For this purpose, a recently developed laboratory technology was used, i.e. sedimentation Field-Flow Fractionation. This chromatographic-like separation technology was demonstrated to be particularly selective for isolation and separation of micron-sized biological particles. Sedimentation Field-Flow Fractionation operated on the steric-hyperlayer mode was used to isolate the parasite from the remanent ascitic contaminants of different origins and from red blood cells. With this technology, 86% recovery with 97% viability was obtained in less than 30 min.
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Red blood cell separations by gravitational Field-Flow Fractionation: instrumentation and applications
TrAC Trends in Analytical Chemistry, 1995Co-Authors: Agnès Bernard, Bernard Paulet, Valérie Colin, Philippe J.p. CardotAbstract:Abstract Field-Flow Fractionation (FFF), first described more than 20 years ago, is in constant development and, surprisingly, the simplest method, gravitational Field-Flow Fractionation (GFFF), appears to be very useful in cell separations —although this is still at an early stage of development. We describe here the design of a very simple biocompatible separator which can directly replace the Chromat-ographic column in an HPLC system. The relative complexity of the elution of cellular material is shown for the case of human red blood cells (RBC) of different characteristics and in this paper we show the versatility and selectivity of FFF methods in micron-scale separations.
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Isolation of microfilariae from blood by gravitational Field-Flow Fractionation.
Journal of chromatography, 1991Co-Authors: Annabelle Merino, Christian Bories, Jean-charles Gantier, Philippe J.p. CardotAbstract:Abstract Over 100 million persons suffer from diseases caused by filariae infestation, and one billion are at risk. A simple isolation method for both analytical and preparative separation is presented. Based on the simplest Field-Flow Fractionation technique, the gravitational one, effective isolation of microfilariae is achieved. Microfilariae are eluted in the void volume of the channel without pollution by red blood cells. The red blood cell elution peak shows a total absence of microfilariae, as demonstrated after fraction collection and microscopic investigation. The elution mode of microfilariae and red blood cells appears to be a steric one, as confirmed by a reinjection experiment. The simplicity, low cost and the relatively short time required for this separation (10 min) indicate that gravitational Field-Flow Fractionation could become a new separation tool for screening of microfilariae. With both live and dead microfilariae, the high recovery (66–80%) allows preparative Fractionation for diagnostic purposes or fundamental research.
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Separation of living red blood cells by gravitational Field-Flow Fractionation.
Journal of chromatography, 1991Co-Authors: Philippe J.p. Cardot, Jean Gerota, Michel MartinAbstract:The Field-Flow Fractionation technique, using the earth's gravitational Field, has been applied to peripheral blood cell populations. A more or less symmetrical, gaussian-like, elution peak is generally observed for the red cell population. The bimodal cell population obtained after a massive transfusion is shown to result in a shoulder on the red blood cell elution profile. In one case where a similar shouldering peak was obtained from a non-transfused donor, the existence of an immunological double population has been demonstrated. This suggests that Field-Flow Fractionation has some potential for complementary biomedical diagnosis.
Maciej Zborowski - One of the best experts on this subject based on the ideXlab platform.
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Characterization of magnetic nanoparticles using programmed quadrupole magnetic Field-Flow Fractionation.
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2010Co-Authors: P. Stephen Williams, Francesca Carpino, Maciej ZborowskiAbstract:Quadrupole magnetic Field-Flow Fractionation is a relatively new technique for the separation and characterization of magnetic nanoparticles. Magnetic nanoparticles are often of composite nature having a magnetic component, which may be a very finely divided material, and a polymeric or other material coating that incorporates this magnetic material and stabilizes the particles in suspension. There may be other components such as antibodies on the surface for specific binding to biological cells, or chemotherapeutic drugs for magnetic drug delivery. Magnetic Field-Flow Fractionation (MgFFF) has the potential for determining the distribution of the magnetic material among the particles in a given sample. MgFFF differs from most other forms of Field-Flow Fractionation in that the magnetic Field that brings about particle separation induces magnetic dipole moments in the nanoparticles, and these potentially can interact with one another and perturb the separation. This aspect is examined in the present work. Samples of magnetic nanoparticles were analysed under different experimental conditions to determine the sensitivity of the method to variation of conditions. The results are shown to be consistent and insensitive to conditions, although magnetite content appeared to be somewhat higher than expected.
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analysis of magnetic nanoparticles using quadrupole magnetic Field Flow Fractionation
Journal of Magnetism and Magnetic Materials, 2005Co-Authors: Francesca Carpino, Maciej Zborowski, Lee R. Moore, Jeffrey J. Chalmers, Stephen P WilliamsAbstract:The new technique of quadrupole magnetic Field-Flow Fractionation is described. It is a separation and characterization technique for particulate magnetic materials. Components of a sample are eluted from the separation channel at times dependent on the strength of their interaction with the magnetic Field. A quadrupole electromagnet allows a programmed reduction of Field strength during analysis of polydisperse samples.
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Quadrupole magnetic Field-Flow Fractionation for the analysis of magnetic nanoparticles
Journal of Physics: Conference Series, 2005Co-Authors: Francesca Carpino, Maciej Zborowski, Lee R. Moore, Jeffrey J. Chalmers, P. Stephen WilliamsAbstract:Field-Flow Fractionation (FFF) is an analytical scale separation and characterizatio technique for macromolecules and particles. A quadrupole magnetic FFF device has bee constructed for analyzing magnetic nanoparticles. It is shown to give reproducible results and be capable of distinguishing between different lots of a commercial magnetic nanoparticle material.
Francesca Carpino - One of the best experts on this subject based on the ideXlab platform.
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Characterization of magnetic nanoparticles using programmed quadrupole magnetic Field-Flow Fractionation.
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2010Co-Authors: P. Stephen Williams, Francesca Carpino, Maciej ZborowskiAbstract:Quadrupole magnetic Field-Flow Fractionation is a relatively new technique for the separation and characterization of magnetic nanoparticles. Magnetic nanoparticles are often of composite nature having a magnetic component, which may be a very finely divided material, and a polymeric or other material coating that incorporates this magnetic material and stabilizes the particles in suspension. There may be other components such as antibodies on the surface for specific binding to biological cells, or chemotherapeutic drugs for magnetic drug delivery. Magnetic Field-Flow Fractionation (MgFFF) has the potential for determining the distribution of the magnetic material among the particles in a given sample. MgFFF differs from most other forms of Field-Flow Fractionation in that the magnetic Field that brings about particle separation induces magnetic dipole moments in the nanoparticles, and these potentially can interact with one another and perturb the separation. This aspect is examined in the present work. Samples of magnetic nanoparticles were analysed under different experimental conditions to determine the sensitivity of the method to variation of conditions. The results are shown to be consistent and insensitive to conditions, although magnetite content appeared to be somewhat higher than expected.
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analysis of magnetic nanoparticles using quadrupole magnetic Field Flow Fractionation
Journal of Magnetism and Magnetic Materials, 2005Co-Authors: Francesca Carpino, Maciej Zborowski, Lee R. Moore, Jeffrey J. Chalmers, Stephen P WilliamsAbstract:The new technique of quadrupole magnetic Field-Flow Fractionation is described. It is a separation and characterization technique for particulate magnetic materials. Components of a sample are eluted from the separation channel at times dependent on the strength of their interaction with the magnetic Field. A quadrupole electromagnet allows a programmed reduction of Field strength during analysis of polydisperse samples.
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Quadrupole magnetic Field-Flow Fractionation for the analysis of magnetic nanoparticles
Journal of Physics: Conference Series, 2005Co-Authors: Francesca Carpino, Maciej Zborowski, Lee R. Moore, Jeffrey J. Chalmers, P. Stephen WilliamsAbstract:Field-Flow Fractionation (FFF) is an analytical scale separation and characterizatio technique for macromolecules and particles. A quadrupole magnetic FFF device has bee constructed for analyzing magnetic nanoparticles. It is shown to give reproducible results and be capable of distinguishing between different lots of a commercial magnetic nanoparticle material.
Dora Melucci - One of the best experts on this subject based on the ideXlab platform.
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Field-Flow Fractionation of cells with chemiluminescence detection.
Journal of chromatography. A, 2004Co-Authors: Dora Melucci, Pierluigi Reschiglian, Andrea Zattoni, Barbara Roda, Sonia Casolari, Aldo RodaAbstract:Field-Flow Fractionation is a separation technique characterized by a retention mechanism which makes it suitable for sorting cells over a short analysis time, with low sample carry-over and preserving cell viability. Thanks to its high sensitivity, chemiluminescence detection is suitable for the quantification of just a few cells expressing chemiluminescence or bioluminescence. In this work, different formats for coupling gravitational Field-Flow Fractionation and chemiluminescence detection are explored to achieve ultra-sensitive cell detection in the framework of cell sorting. The study is carried out using human red blood cells as model sample. The best performance is obtained with the on-line coupling format, performed in post-column Flow-injection mode. Red cells are isolated from diluted whole human blood in just a few minutes and detected using the liquid phase chemiluminescent reaction of luminol catalysed by the red blood cell heme. The limit of detection is a few hundred injected cells. This is lower than the limit of detection usually achieved by means of conventional colorimetric/turbidimetric methods, and it corresponds to a red blood cell concentration in the injected sample of five orders of magnitude lower than in whole blood.
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Coupling gravitational and Flow Field-Flow Fractionation, and size-distribution analysis of whole yeast cells.
Analytical and bioanalytical chemistry, 2004Co-Authors: Ramsés Sanz, Pierluigi Reschiglian, Andrea Zattoni, Lluís Puignou, Maria Teresa Galceran, Dora MelucciAbstract:This work continues the project on Field-Flow Fractionation characterisation of whole wine-making yeast cells reported in previous papers. When yeast cells are fractionated by gravitational Field-Flow Fractionation and cell sizing of the collected fractions is achieved by the electrosensing zone technique (Coulter counter), it is shown that yeast cell retention depends on differences between physical indexes of yeast cells other than size. Scanning electron microscopy on collected fractions actually shows co-elution of yeast cells of different size and shape. Otherwise, the observed agreement between the particle size distribution analysis obtained by means of the Coulter counter and by Flow Field-Flow Fractionation, which employs a second mobile phase Flow as applied Field instead of Earth's gravity, indicates that yeast cell density can play a major role in the gravitational Field-Flow Fractionation retention mechanism of yeast cells, in which Flow Field-Flow Fractionation retention is independent of particle density. Flow Field-Flow Fractionation is then coupled off-line to gravitational Field-Flow Fractionation for more accurate characterisation of the doubly-fractionated cells. Coupling gravitational and Flow Field-Flow Fractionation eventually furnishes more information on the multipolydispersity indexes of yeast cells, in particular on their shape and density polydispersity.
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Flow Field‐Flow Fractionation with chemiluminescence detection for Flow‐assisted, multianalyte assays in heterogeneous phase
Journal of Separation Science, 2003Co-Authors: Pierluigi Reschiglian, Andrea Zattoni, Barbara Roda, Dora Melucci, Massimo Guardigli, Aldo RodaAbstract:On-line, continuous chemiluminescence detection has been recently applied to gravitational Field-Flow Fractionation as a new method suitable for Flow-assisted assays based on the separation between the analyte in solution and the analyte bound to micrometer-sized particles. In this work, Flow Field-Flow Fractionation coupled with off-line chemiluminescence detection is exploited for the development of Flow-assisted, multianalyte assays. Micrometer-sized, polystyrene beads coated with enzymes suitable for chemiluminescence detection, such as horseradish peroxidase and alkaline phosphatase, are used as model samples. The high size-based selectivity of Flow Field-Flow Fractionation and specificity of chemiluminescence detection make possible, in a single run with very short analysis time, the simultaneous, high sensitivity detection of the different enzymes linked to beads of different size.
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Working without accumulation membrane in Flow Field-Flow Fractionation.
Analytical chemistry, 2000Co-Authors: Pierluigi Reschiglian, Dora Melucci, And A. Zattoni, L. Malló, M. Hansen, And A. Kummerow, M. MillerAbstract:Nonideal interaction of sample with the separation device is a difficulty found in chromatographic methods as well as in Field-Flow Fractionation. However, in Field-Flow Fractionation (FFF), greater flexibility in the choice of carrier solution composition is possible, thus reducing the need of a wide choice of surface chemistry when nonideal sample interaction is to be minimized. The use of an ultrafiltration membrane as the surface for the accumulation wall is common practice in Flow Field-Flow Fractionation. Typical membranes in use are laminates of a skin membrane onto a backing material such as woven polyester. At this point, only a limited choice of membrane chemistries is available. Many membranes have been developed for protein applications as membranes are widely used in the pharmaceutical industries. While these membranes work well for protein applications, Flow Field-Flow Fractionation is applicable to polymeric particulate as well as protein samples. Thus, sample interaction with the membrane surface is possible with nonprotein applications and these interactions can induce significant secondary effects on retention ratio and affect instrumental reliability. Also, the woven texture of membranes may detrimentally affect the FFF separation. For these reasons, the study of Flow Field-Flow Fractionation using a flat, smooth surface of controlled chemistry is of relevance. We present here the results of a new, membraneless channel that uses a bare frit as the accumulation wall and that is intended for analysis of micrometer-sized particles only. Selectivity results are comparable to those obtained with the membrane, while relative sample recovery indicates that the best quantitative performance can be obtained without the membrane. Moreover, neither sample immobilization nor losses through the frit occur when operating membraneless. On the other hand, first experimental evidence of a certain level of frit surface activity suggests that optimization of experimental conditions is required.