4 results on '"Christophe Védrine"'
Search Results
2. Assessing the Functional Heterogeneity of Monocytes in Human Septic Shock: a Proof-of-Concept Microfluidic Assay of TNFα Secretion
- Author
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Jean-François Llitjos, Yacine Bounab, Christophe Rousseau, Sophie Dixneuf, Blandine Rimbault, Jean-Daniel Chiche, Julien Textoris, Frédéric Pène, and Christophe Védrine
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Adult ,Lipopolysaccharides ,Male ,0301 basic medicine ,medicine.medical_treatment ,media_common.quotation_subject ,Microfluidics ,Immunology ,microfluidic ,Proof of Concept Study ,Monocytes ,Flow cytometry ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Fluorescence microscope ,Humans ,Immunology and Allergy ,Secretion ,Internalization ,Original Research ,Aged ,media_common ,Aged, 80 and over ,Immunosuppression Therapy ,tolerance ,medicine.diagnostic_test ,Tumor Necrosis Factor-alpha ,Septic shock ,Chemistry ,Monocyte ,Immunosuppression ,HLA-DR Antigens ,RC581-607 ,Middle Aged ,Flow Cytometry ,medicine.disease ,Shock, Septic ,030104 developmental biology ,medicine.anatomical_structure ,monocyte ,septic shock ,Female ,Tumor necrosis factor alpha ,immune suppression ,Immunologic diseases. Allergy ,030217 neurology & neurosurgery - Abstract
ObjectiveThe development of advanced single-cell technologies to decipher inter-cellular heterogeneity has enabled the dynamic assessment of individual cells behavior over time, overcoming the limitation of traditional assays. Here, we evaluated the feasibility of an advanced microfluidic assay combined to fluorescence microscopy to address the behavior of circulating monocytes from septic shock patients.MethodsSeven septic shock patients and ten healthy volunteers were enrolled in the study. Using the proposed microfluidic assay we investigated the production over time of LPS-elicited TNFα by single monocytes encapsulated within droplets. Cellular endocytic activity was assessed by internalization of magnetic nanoparticles. Besides, we assessed HLA-DR membrane expression and LPS-induced TNFα production in monocytes through classical flow cytometry assays.ResultsConsistent with the flow cytometry results, the total number of TNFα molecules secreted by encapsulated single monocytes was significantly decreased in septic shock patients compared to healthy donors. TNFα production was dampened as soon as 30 and 60 minutes after LPS stimulation in monocytes from septic patients. Furthermore, the microfluidic assay revealed heterogeneous individual behavior of monocytes from septic shock patients. Of note, monocytes from both healthy donors and patients exhibited similar phagocytic activities over time.ConclusionThe microfluidic assay highlights the functional heterogeneity of monocytes, and provides in-depth resolution in assessing the hallmark monocyte deactivation encountered in post-septic immunosuppression.
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- 2021
3. Optical whole-cell biosensor using Chlorella vulgaris designed for monitoring herbicides
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Claude Durrieu, Christophe Védrine, Jean-Claude Leclerc, Canh Tran-Minh, Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Poudres et Matériaux Multi-Composants (P2MC-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Equipe d'Ecophysiologie (EE-FSSE), Faculté des Sciences de Saint-Etienne, Laboratoire des Sciences de l'Environnement (LSE-ENTPE), École Nationale des Travaux Publics de l'État (ENTPE)-Université de Lyon-Ministère de l'Ecologie, du Développement Durable, des Transports et du Logement, Université Jean Monnet, and Ecole Nationale des Travaux Publics de l'Eta
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[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,Algae ,Chlorella vulgaris ,Biomedical Engineering ,Biophysics ,Simazine ,Biosensing Techniques ,Chlorella ,Ecotoxicology ,Sensitivity and Specificity ,Fluorescence ,chemistry.chemical_compound ,Fluorometer ,Botany ,Electrochemistry ,Fiber Optic Technology ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,Atrazine ,[INFO.INFO-BT]Computer Science [cs]/Biotechnology ,Chlorophyll fluorescence ,Cells, Cultured ,Detection limit ,Chromatography ,Dose-Response Relationship, Drug ,biology ,Herbicides ,Temperature ,Reproducibility of Results ,Equipment Design ,General Medicine ,Cells, Immobilized ,Flow Cytometry ,biology.organism_classification ,chemistry ,Herbicide ,Biosensor ,Water Pollutants, Chemical ,Environmental Monitoring ,Biotechnology - Abstract
International audience; An optical biosensor was designed for determination of herbicides as aquatic contaminants. Detection was obtained with immobilised Chlorella vulgaris microalgae entrapped on a quartz microfibre filter and placed in a five-membrane-home-made-flow cell. The algal chlorophyll fluorescence modified by the presence of herbicides was collected at the tip of an optical fibre bundle and sent to a fluorimeter. A continuous culture was set up to produce algal cells in reproducible conditions for measurement optimisation. Effects of flow rate, algal density, temperature, and pH on the biosensor response to atrazine were studied. Reversibility and detection limits were determined for DNOC and atrazine, simazine, isoproturon, diuron. Detection of photosystem II (PSII) herbicides was achieved at sub-ppb concentration level.
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- 2003
4. Dynamic single-cell phenotyping of immune cells using the microfluidic platform DropMap
- Author
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Nathan Aymerich, Magda Rybczynska, Julien Textoris, Sophie Dixneuf, Jérôme Bibette, Fabienne Venet, Jean-François Llitjos, Cécile Chauvel, Yacine Bounab, Guilhem Chenon, Cyril Guyard, Iain A. Gillespie, Virginie Moucadel, Pierre Cortez, Klaus Eyer, Alain Troesch, Christophe Védrine, Philippe Leissner, Jean Baudry, Andrew D. Griffiths, Trang Tran, Guillaume Monneret, Alexandre Pachot, Maxime Mistretta, Chimie-Biologie-Innovation (UMR 8231) (CBI), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and BIOASTER Microbiology Technology Institute [Lyon]
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General Biochemistry, Genetics and Molecular Biology ,Flow cytometry ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Immune system ,Lab-On-A-Chip Devices ,medicine ,Fluorescence microscope ,Image Processing, Computer-Assisted ,Animals ,Humans ,Mass cytometry ,Secretion ,030304 developmental biology ,0303 health sciences ,B-Lymphocytes ,biology ,medicine.diagnostic_test ,Chemistry ,ELISPOT ,Cell biology ,Phenotype ,Microscopy, Fluorescence ,Immune System ,biology.protein ,Cytokine secretion ,Female ,Antibody ,Single-Cell Analysis ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,030217 neurology & neurosurgery - Abstract
Characterization of immune responses is currently hampered by the lack of systems enabling quantitative and dynamic phenotypic characterization of individual cells and, in particular, analysis of secreted proteins such as cytokines and antibodies. We recently developed a simple and robust microfluidic platform, DropMap, to measure simultaneously the kinetics of secretion and other cellular characteristics, including endocytosis activity, viability and expression of cell-surface markers, from tens of thousands of single immune cells. Single cells are compartmentalized in 50-pL droplets and analyzed using fluorescence microscopy combined with an immunoassay based on fluorescence relocation to paramagnetic nanoparticles aligned to form beadlines in a magnetic field. The protocol typically takes 8–10 h after preparation of microfluidic chips and chambers, which can be done in advance. By contrast, enzyme-linked immunospot (ELISPOT), flow cytometry, time-of-flight mass cytometry (CyTOF), and single-cell sequencing enable only end-point measurements and do not enable direct, quantitative measurement of secreted proteins. We illustrate how this system can be used to profile downregulation of tumor necrosis factor-α (TNF-α) secretion by single monocytes in septic shock patients, to study immune responses by measuring rates of cytokine secretion from single T cells, and to measure affinity of antibodies secreted by single B cells. This protocol describes a microfluidic platform for dynamic high-throughput analysis of the phenotypes of single cells. Cell-surface markers and secreted proteins are quantified and characterized by fluorescence detection using tailored immunoassays.
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