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Articles de revues sur le sujet "Greffage par activation plasma"
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Nejman, Alicja, Irena Kamińska, Izabela Jasińska, Grzegorz Celichowski et Małgorzata Cieślak. « Influence of Low-Pressure RF Plasma Treatment on Aramid Yarns Properties ». Molecules 25, no 15 (30 juillet 2020) : 3476. http://dx.doi.org/10.3390/molecules25153476.
Texte intégralRésumé :
The aim of the study was to modify the surface free energy (SFE) of meta- (mAr) and para-aramid (pAr) yarns by their activation in low-pressure air radio frequency (RF) (40 kHz) plasma and assessment of its impact on the properties of the yarns. After 10 and 90 min of activation, the SFE value increased, respectively, by 14% and 37% for mAr, and by 10% and 37% for pAr. The value of the polar component increased, respectively by 22% and 57% for mAr and 20% and 62% for pAr. The value of the dispersion component for mAr and pAr increased respectively by 9% and 25%. The weight loss decreased from 49% to 46% for mAr and 62% to 50% for pAr after 90 min of activation. After 90 min, the specific strength for mAr did not change and for pAr it decreased by 40%. For both yarns, the 10 min activation in plasma is sufficient to prepare their surface for planned nanomodification.
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Antoniak, Silvio, Kohei Tatsumi, Michael Bode, Swetha Vanja, Julie C. Williams et Nigel Mackman. « Protease-Activated Receptor 1 Enhances Poly I:C Induction of the Antiviral Response in Macrophages and Mice ». Journal of Innate Immunity 9, no 2 (8 novembre 2016) : 181–92. http://dx.doi.org/10.1159/000450853.
Texte intégralRésumé :
The coagulation cascade is activated during viral infections as part of the host defense system. Coagulation proteases activate cells by cleavage of protease-activated receptors (PARs). Recently, we reported that the activation of PAR-1 enhanced interferon (IFN)β and CXCL10 expression in cardiac fibroblasts and in the hearts of mice infected with Coxsackievirus B3. In this study, we used the double-stranded RNA mimetic polyinosinic:polycytidylic acid (poly I:C) to induce an antiviral response in macrophages and mice. Activation of PAR-1 enhanced poly I:C induction of IFNβ and CXCL10 expression in the murine macrophage cell line RAW264.7, bone-marrow derived mouse macrophages (BMM) and mouse splenocytes. Next, poly I:C was used to induce a type I IFN innate immune response in the spleen and plasma of wild-type (WT) and PAR-1-/- mice. We found that poly I:C treated PAR-1-/- mice and WT mice given the thrombin inhibitor dabigatran etexilate exhibited significantly less IFNβ and CXCL10 expression in the spleen and plasma than WT mice. These studies suggest that thrombin activation of PAR-1 contributes to the antiviral response in mice.
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Sparkenbaugh, Erica, John H. Griffin, Laurent O. Mosnier et Rafal Pawlinski. « Biased PAR-1 Signaling Regulates Thrombo-Inflammation in a Mouse Model of Sickle Cell Disease ». Blood 136, Supplement 1 (5 novembre 2020) : 16–17. http://dx.doi.org/10.1182/blood-2020-139862.
Texte intégralRésumé :
Thrombin and activated protein C (APC) are serine proteases involved in coagulation and inflammatory responses. Protease activated receptor-1 (PAR-1) is a G-protein coupled receptor (GPCR) activated by proteolytic cleavage of the extracellular N-terminus. PAR-1 cleavage at R41 by thrombin or at R46 by APC creates unique tethered ligands that activate different signaling pathways. On endothelial cells, thrombin employs PAR-1 to promote endothelial barrier disruption, vascular leakage, and inflammation. In contrast, APC employs PAR-1 to stabilize endothelial barrier and provides anti-inflammatory and anti-apoptotic activities. These opposing effects of PAR-1 activation are a classic example of "GPCR biased signaling". We have previously demonstrated that PAR-1 deficiency in all hematopoietic cells reduces heme-induced vascular stasis in sickle mice. In contrast it does not affect the elevated plasma levels of IL-6 or thrombin-antithrombin (TAT) complexes observed in sickle cell disease (SCD) mice compared to non-SCD controls during steady state. In this study, we investigated the effects of thrombin- and APC-induced PAR-1 activation on thromboinflammation in the well-characterized Townes mouse model of SCD. Procoagulant and proinflammatory responses were analyzed in control (AA) and sickle (SS) mice at steady state (saline injection) and 5 hours after TNFα (2 µg/kg, i.p.) to mimic the pro-inflammatory milieu that occurs during painful crisis in SCD patients. As previously described, SS mice had elevated plasma levels of TAT compared to AA mice (8.6± 2.4 vs 3.5±0.7ng/mL; p<0.05), that were further enhanced in SS mice by TNFα injection (21.5 ± 4.2 ng/mL, p<0.001). A similar pattern was observed for plasma levels of IL-6 (AA: 2.4±2 vs SS: 18±7.8 ng/mL, p<0.05; SS+TNFα: 231 ± 32 ng/mL, p<0.0001 vs SS). Using these experimental conditions, we first investigated the role of endogenous APC in SCD. We used a rat anti-mouse protein C mAb (SPC-54), which inhibits the active site of APC, thereby blocking all its enzymatic activities, including PAR-1-dependent signaling and anticoagulant actions. SS mice were injected with anti-APC SPC54 (10 mg/kg) or control IgG antibodies. Eighteen hours later both groups of mice were injected with either saline or TNFα and plasma samples were collected 5 hours later. We TNFαSSdata suggest that endogenous APC has anticoagulant and anti-inflammatory roles for both the steady state and after TNFα challenge. To address the individual roles of thrombin and APC signaling on vascular inflammation in SCD, we used mice with point mutations in PAR-1 at R41 or R46. Mutation of R41 to Glu (R41Q) renders PAR-1 insensitive to thrombin while preserving APC-mediated cleavage at R46. Mutation of R46 to Glu (R46Q) ablates APC's cytoprotective effects. Bone marrow (BM) from SS mice was transplanted into PAR-1WT, PAR-1R41Q, or PAR-1R46Q mice to generate SSBM mice with either normal PAR-1 (SSBM/PAR-1WT) or the mutated form of this receptor on all non-hematopoietic cells (SSBM/PAR-1R41Q and SSBM/PAR-1R46Q). Four months after BM transplantation, plasma levels of TAT, IL-6, and HMGB1 were analyzed in all 3 groups at steady state or 5 hours after TNFα challenge. Neither the PAR-1R41Q nor PAR-1R46Q mutation on non-hematopoietic cells affected plasma levels of TAT, IL-6, or HMGB1 in SS mice at steady state. Interestingly, plasma levels of IL-6 were significantly elevated in SSBM/PAR-1R46Q mice and reduced in SSBM/PAR-1R41Q mice compared to SSBM/PAR-1WT mice after TNFα challenge, with a statistically significant difference between the two PAR-1 mutant groups. Furthermore plasma levels of TAT and HMGB1 were significantly reduced in SSBM/PAR-1R41Q but not changed in SSBM/PAR-1R46Q mice after TNFα challenge (Figure 2A-C). These data suggest that PAR-1 activation at R41 regulates TAT, IL-6, and HMGB1, whereas activation of R46 negatively regulates IL-6 in sickle mice during TNFα challenge. Our data imply that pharmacological approaches aiming to eliminate thrombin-dependent, while preserving APC-dependent PAR-1 activation, may be effective in attenuating thrombo-inflamatory complications associated with SCD. Studies evaluating the effects of R41Q and R46Q mutations on microvascular stasis in SS mice are currently ongoing. Disclosures No relevant conflicts of interest to declare.
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Chantrathammachart, Pichika, Erica M. Sparkenbaugh, Nigel Mackman, Nigel S. Key et Rafal Pawlinski. « Protease Activated Receptor 2 (PAR-2) Promotes Vascular Inflammation in a Mouse Model of Sickle Cell Disease ». Blood 120, no 21 (16 novembre 2012) : 375. http://dx.doi.org/10.1182/blood.v120.21.375.375.
Texte intégralRésumé :
Abstract Abstract 375 Sickle cell disease (SCD) is a hematologic disorder caused by a single nucleotide mutation of the beta-globin gene. It is associated with increased tissue factor (TF) expression, activation of coagulation and chronic vascular inflammation. Using two mouse models of SCD (BERK and Townes mice), we have recently demonstrated that inhibition of TF with a rat anti-mouse TF (1H1) antibody not only abolishes activation of coagulation (measured by plasma levels of thrombin anti-thrombin (TAT) complexes) but also reduces inflammation and endothelial cell (EC) injury, indicated by attenuation of plasma levels of IL-6 and sVCAM-1, respectively. Furthermore, we showed that EC-specific deletion of TF gene significantly reduced plasma levels of IL-6 but had no effect on activation of coagulation (TAT) or EC injury (sVCAM-1). These data suggest that EC-TF is primarily involved in signaling rather than activation of coagulation. Since TF:factor VIIa complex-dependent activation of protease activated receptor-2 (PAR-2) has been shown to promote inflammation, we have now investigated the role of PAR-2 expressed by non-hematopoietic cells in the pathology of SCD. PAR-2+/+ and PAR-2−/− mice were lethally irradiated and transplanted with bone marrow from BERK SS (sickle cell mice) or BERK AA (non-sickle control) mice(n=6–10). Four months after bone marrow transplantation, mice were sacrificed and the reconstitution of bone marrow was confirmed by electrophoretic analysis of the different forms of hemoglobin. PAR-2+/+ mice transplanted with bone marrow from BERK SS mice had reduced number of red blood cells and hematocrit compared to PAR-2+/+ mice transplanted with bone marrow from BERK AA mice. PAR-2 deficiency in all non-hematopoietic cells had no effect on these hematologic parameters. Furthermore, PAR-2+/+ mice transplanted with bone marrow from BERK SS mice had increased number of monocytes (3.1 fold, p<0.0001) and neutrophils (2.5 fold, p<0.05) in the blood. Interestingly, sickle cell mice lacking PAR-2 in non-hematopoietic cells had significantly reduced neutrophil counts compared to the sickle cell mice with normal levels of PAR-2 (1.9+/−0.2 vs. 5.4+/−1.4 X103/ul; p<0.05), whereas monocytes counts were not affected. Compared to non-sickle controls, sickle cell mice had increased plasma levels of TAT (1.9 fold, p<0.01), IL-6 (6.8 fold, P<0.0001), serum amyloid protein SAP (6.5 fold, p<0.01; mouse homolog of human C reactive protein) and sVCAM-1 (1.4 fold, p<0.01). Moreover, increased levels of myeloperoxidase (MPO) were observed in the livers of sickle cell mice (3 fold, p<0.0001). Importantly, sickle cell mice lacking PAR-2 expression in all non-hematopoietic cells demonstrated significant reduction of plasma levels of IL-6 (9.4+/−0.9 vs. 18.9+/−4.5 pg/ml; p<0.05) and SAP (60.5+/−12.9 vs. 182.8+/−62.5ug/ml; p<0.05) compared to sickle cell mice with normal levels of PAR2 expression. In addition, deletion of PAR-2 also significantly reduced MPO levels in the liver of sickle cell mice (53.7+/−3.5 vs. 117.4+/−16.9 ng/mg protein; p<0.0001). In contrast, PAR-2 deficiency in non-hematopoietic cells had no effect on activation of coagulation (TAT) or EC injury (sVCAM-1) in sickle mice. Our data demonstrate that vascular inflammation observed in a mouse model of sickle cell disease is mediated, in part, by PAR-2 expressed by non-hematopoietic cells. Activation of EC (sVCAM-1) was not affected by PAR-2 deficiency. Ongoing studies are investigating the possible contribution of the TF-thrombin-PAR1 pathway to the EC activation in SCD. Disclosures: No relevant conflicts of interest to declare.
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Tatsumi, Kohei, Silvio Antoniak et Nigel Mackman. « Role of the Thrombin-PAR-1 Pathway in Coxsackievirus Induced Hepatitis ». Blood 124, no 21 (6 décembre 2014) : 1470. http://dx.doi.org/10.1182/blood.v124.21.1470.1470.
Texte intégralRésumé :
Abstract Objective: Coxsackievirus B3 (CVB3) can infect different tissues including the heart and liver. Recently, we found that activation of the coagulation cascade and protease-activated receptor 1 (PAR-1) enhances toll-like receptor-3 (TLR3) mediated interferon-β (IFN-β) expression and protects mice from CVB3-induced myocarditis. Here, we investigated the role of PAR-1 in early anti-viral responses in mice and isolated hepatocytes. Methods: Wild-type (WT) and PAR-1 deficient (PAR-1-/-) mice were infected with CVB3 intraperitoneally. The innate immune response, viral load, liver enzyme plasma levels, and inflammation levels were analyzed. Bone-marrow transplantation experiments with the combination of WT mice PAR-1-/- mice were performed to identify the cellular source of PAR-1 contributing to the innate immune response to CVB3. We also analyzed the effect of the direct thrombin inhibition with dabigatran etexilate on CVB3 hepatitis. In addition, we analyzed the effect of PAR-1 activation on TLR3-dependent interferon (IFN)-β expression in primary mouse hepatocytes and the human hepatocyte cell line PH5CH8 in vitro. Results: PAR-1-/- mice exhibited a reduced early innate immune response in the liver at day 4 after infection, which was associated at later times (day 8) to higher viral titers in the liver, increased alanine transaminase plasma levels and more remarkable inflammation compared to control WT mice. Bone marrow transplantation experiments demonstrated that PAR-1 on non-hematopoietic played the major role in the innate immune response of CVB3 hepatitis. Stimulation of PAR-1 with either thrombin or agonist peptide on primary mouse hepatocytes and human PH5CH8 cells in vitro enhanced the antiviral response to dsRNA by increasing IFN-β and C-X-C motif chemokine 10 (CXCL10) expressions, supporting the results of in vivo experiments. Conclusion: Our results suggest that activation of PAR-1 on hepatocytes enhances the innate immune response to CVB3 in the liver. Disclosures No relevant conflicts of interest to declare.
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McRedmond, James P., Patrick Harriott, Brian Walker et Desmond J. Fitzgerald. « Streptokinase-induced platelet activation involves antistreptokinase antibodies and cleavage of protease-activated receptor-1 ». Blood 95, no 4 (15 février 2000) : 1301–8. http://dx.doi.org/10.1182/blood.v95.4.1301.004k24_1301_1308.
Texte intégralRésumé :
Streptokinase activates platelets, limiting its effectiveness as a thrombolytic agent. The role of antistreptokinase antibodies and proteases in streptokinase-induced platelet activation was investigated. Streptokinase induced localization of human IgG to the platelet surface, platelet aggregation, and thromboxane A2production. These effects were inhibited by a monoclonal antibody to the platelet Fc receptor, IV.3. The platelet response to streptokinase was also blocked by an antibody directed against the cleavage site of the platelet thrombin receptor, protease-activated receptor-1 (PAR-1), but not by hirudin or an active site thrombin inhibitor, Ro46-6240. In plasma depleted of plasminogen, exogenous wild-type plasminogen, but not an inactive mutant protein, S741A plasminogen, supported platelet aggregation, suggesting that the protease cleaving PAR-1 was streptokinase-plasminogen. Streptokinase-plasminogen cleaved a synthetic peptide corresponding to PAR-1, resulting in generation of PAR-1 tethered ligand sequence and selectively reduced binding of a cleavage-sensitive PAR-1 antibody in intact cells. A combination of streptokinase, plasminogen, and antistreptokinase antibodies activated human erythroleukemic cells and was inhibited by pretreatment with IV.3 or pretreating the cells with the PAR-1 agonist SFLLRN, suggesting Fc receptor and PAR-1 interactions are necessary for cell activation in this system also. Streptokinase-induced platelet activation is dependent on both antistreptokinase-Fc receptor interactions and cleavage of PAR-1.
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Tholanikunnel, Baby, Berhane Ghebrehiwet, Allen Kaplan et Kusumam Joseph. « Interaction of high molecular weight kininogen binding proteins on endothelial cells ». Thrombosis and Haemostasis 91, no 01 (2004) : 61–70. http://dx.doi.org/10.1160/th03-07-0471.
Texte intégralRésumé :
SummaryCell surface proteins reported to participate in the binding and activation of the plasma kinin-forming cascade includes gC1qR, cytokeratin 1 and u-PAR. Each of these proteins binds high molecular weight kininogen (HK) as well as Factor XII. The studies on the interaction of these proteins, using dot-blot analysis, revealed that cytokeratin 1 binds to both gC1qR and u-PAR while gC1qR and u-PAR do not bind to each other. The binding properties of these proteins were further analyzed by gel filtration. When biotinylated cytokeratin 1 was incubated with either gC1qR or u-PAR and gel filtered, a new, higher molecular weight peak containing biotin was observed indicating complex formation. The protein shift was also similar to the biotin shift. Further, immunoprecipitation of solubilized endothelial cell plasma membrane proteins with anti-gC1qR recovered both gC1qR and cytokeratin 1, but not u-PAR. Immunoprecipitation with anti-u-PAR recovered only u-PAR and cytokeratin 1. By competitive ELISA, gC1qR inhibits u-PAR from binding to cytokeratin 1; u-PAR inhibits gC1qR binding to a lesser extent and requires a 10-fold molar excess. Our data suggest that formation of HK (and Factor XII) binding sites along endothelial cell membranes consists of bimolecular complexes of gC1qR-cytokeratin 1 and u-PAR-cytokeratin 1, with gC1qR binding being favored.
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Azim, A. C., K. Barkalow, J. Chou et J. H. Hartwig. « Activation of the small GTPases, rac and cdc42, after ligation of the platelet PAR-1 receptor ». Blood 95, no 3 (1 février 2000) : 959–64. http://dx.doi.org/10.1182/blood.v95.3.959.003k22_959_964.
Texte intégralRésumé :
Stimulation of platelet PAR-1 receptors results in the rapid (10 to 30 seconds) and extensive (30% to 40% of total) guanosine triphosphate (GTP) charging of endogenous platelet rac, previously identified as a possible key intermediate in the signal pathway between PAR-1 and actin filament barbed-end uncapping, leading to actin assembly. During PAR-1–mediated platelet activation, rac distributes from the cell interior to the cell periphery, and this reorganization is resistant to the inhibition of PI-3-kinase activity. Rac, in resting or activated platelets, is Triton X-100 soluble, suggesting that it does not form tight complexes with actin cytoskeletal proteins, though its retention in octyl-glucoside-treated platelets and ultrastructural observations of activated platelets implies that rac binds to plasma membranes, where it can interact with phosphoinositide kinases implicated in actin assembly reactions. PAR-1 stimulation also rapidly and extensively activates cdc42, though, in contrast to rac, some cdc42 associates with the actin cytoskeleton in resting platelets, and the bound fraction increases during stimulation. The differences in subcellular distribution and previous evidence showing quantitatively divergent effects of rac and cdc42 on actin nucleation in permeabilized platelets indicate different signaling roles for these GTPases.
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Tatour, Mifleh, Ma'anit Shapira, Elena Axelman, Shourouk Ghanem, Anat Keren-Politansky, Lilach Bonstein, Benjamin Brenner et Yona Nadir. « Thrombin is a selective inducer of heparanase release from platelets and granulocytes via protease-activated receptor-1 ». Thrombosis and Haemostasis 117, no 07 (2017) : 1391–401. http://dx.doi.org/10.1160/th16-10-0766.
Texte intégralRésumé :
SummaryHeparanase, known to be involved in angiogenesis and metastasis, was shown to form a complex with tissue factor (TF) and to enhance the generation of factor Xa. Platelets and granulocytes contain abundant amounts of heparanase that may enhance the coagulation system upon discharge. It was the aim of this study to identify the inducer and pathway of heparanase release from these cells. Platelets and granulocytes were purified from pooled normal plasma and were incubated with ATP, ADP, epinephrine, collagen, ristocetin, arachidonic acid, serotonin, LPS and thrombin. Heparanase levels were assessed by ELISA, heparanase procoagulant activity assay and western blot analysis. The effects of selective protease-activated receptor (PAR)-1 and 2 inhibitors and PAR-1 and 4 activators were studied. An in-house synthesised inhibitory peptide to heparanase was used to evaluate platelet heparanase involvement in activation of the coagulation system. Heparanase was released from platelets only by thrombin induction while other inducers exerted no such effect. The heparanase level in a platelet was found to be 40 % higher than in a granulocyte. Heparanase released from platelets or granulocytes increased factor Xa generation by three-fold. PAR-1 activation via ERK intracellular pathway was found to induce heparanase release. In conclusion, heparanase is selectively released from platelets and granulocytes by thrombin interacting with PAR-1. Heparanase derived from platelets and granulocytes is involved in activation of the extrinsic coagulation pathway. The present study implies on a potential anticoagulant effect, in addition to anti-platelet effect, of the new clinically studied PAR-1 inhibitors.
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Antoniak, Silvio, Kohei Tatsumi et Nigel Mackman. « The Tissue Factor/Thrombin/Protease-Activated Receptor 1 Pathway Enhances Double-Strand RNA Induced Immune Responses in Macrophages ». Blood 124, no 21 (6 décembre 2014) : 4114. http://dx.doi.org/10.1182/blood.v124.21.4114.4114.
Texte intégralRésumé :
Abstract Introduction: Co-regulation of the immune response and the coagulation cascade after infection is thought to be an ancient response to limit pathogen spread. Recently, we showed that activation of the thrombin receptor, protease-activated receptor 1 (PAR1), on fibroblasts enhanced the innate immune responses to RNA virus infection. Here, we investigated whether PAR1 activation by the extrinsic coagulation pathway contributes to dsRNA-induced innate immune responses in macrophages. Methods: Activation of the type-I interferon (IFN) pathway in the murine macrophage cell line RAW264.7 and bone-marrow derived macrophages (BMDM) from WT and PAR1-/- was analyzed after dsRNA (poly I:C) and/or PAR-1 stimulation. In addition, innate immune responses in the spleen were analyzed in vivo 4 hours after poly I:C (8mg/kg) injection in mice with reduced tissue factor expression (LowTF) or global PAR1 deletion (PAR1-/-) as well as in WT mice with a thrombin inhibitor (dabigatran etexilate, 10g/kg chow) or PAR-1 inhibitor (SCH79797, 25μg/kg). Lastly, we investigated the innate immune response in the spleen of WT and PAR1-/-mice after infection with the single-stranded RNA virus coxsackievirus B3. Results: RAW264.7 and BMDM exhibited a toll-like receptor 3 dependent induction of IFNβ and CXCL10 after poly I:C stimulation. Activation of PAR-1 with either thrombin or agonist peptide enhanced poly I:C induction of IFNβ and CXCL10. A deficiency of tissue factor levels, thrombin inhibition, PAR-1 inhibition or PAR1 deficiency resulted in reduced expression levels of type-I IFNs and IFN-response genes such as CXCL10 in the spleen and plasma in mice given poly I:C. Last, PAR1-/-mice exhibited impaired IFNβ immune response 4 days after coxsackievirus B3 infection compared to WT mice. Conclusion: Our study indicates that the coagulation dependent activation of PAR1 on macrophages is important for anti-viral responses to dsRNA. We speculate that PAR1 inhibition may interfere with anti-viral responses in humans. Disclosures No relevant conflicts of interest to declare.
Thèses sur le sujet "Greffage par activation plasma"
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Couturaud, Benoît. « Nanomatériaux pour applications biotechnologiques : greffage par activation plasma de dendrimères greffés de poly-L-lysine sur le polypropylène ». Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20124/document.
Texte intégralRésumé :
L'immobilisation de biomacromolécules à la surface de polymères peu réactifs est une voie de synthèse de nanomatériaux qui fait actuellement l'objet de nombreuses recherches pour le développement d'applications biologiques et médicales. Nous avons synthétisé de nouveaux nanomatériaux à base de polypropylène (PP) greffé par des dendrimères de lysine (DGL). Les DGL sont parfaitement solubles dans l'eau, biocompatibles, polycationiques à pH neutre et leur structure dendritique particulière font d'eux des macromolécules de plus en plus étudiées en interactions avec les milieux biologiques. Différents traitements par plasma ont permis de fonctionnaliser la surface du PP et plusieurs stratégies ont été adoptées pour greffer les DGL sous forme de monocouche, multicouche ou à partir de brosses de polymères : le greffage direct, les polymérisations non contrôlée et contrôlée de type RAFT associées au plasma d'iode et à la chimie click de surface. L'aptitude des matériaux PP fonctionnalisés par le DGL à interagir avec les milieux biologiques a été étudiée, en particulier l'immobilisation de l'ATP et le comportement vis-à-vis des bactéries et des virus. Les propriétés de ces nanomatériaux sont liées à la réactivité des groupements amine des DGL ainsi qu'à la structure régulière et sphérique des dendrimères. Les résultats obtenus ouvrent de nombreuses applications potentielles pour le traitement des eaux, le diagnostic et la prévention du développement des micro-organismesGreat attention has been focused these last years on tailoring polymer surfaces by immobilizationof suitable molecules for biological and medical applications such as tissue engineering, drug delivery systems, antibacterial supports, and biosensors. In that context, we report the preparation of an original hybrid material based on polypropylene and poly-L-Lysine dendrigrafts (DGL) which are perfectly water soluble, and biocompatible. First, activation of the polypropylene surface (PP) was achieved using plasma treatment. Then, several strategies have been developed to graft DGL onto the PP surface such as (i) direct grafting of DGL after surface activation, (ii) the use of conventional radical polymerization or (iii) RAFT polymerization of monomers from the PP surface. The last methodology favored the increase of the DGL grafts density onto the surface. The ability of PP surface functionalized with DGL to interact with biological media was studied and the modified surfaces open the way to many potential applications in water treatment, diagnosis and prevention of the development of microorganisms
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Wei, Tianyue. « Modification of terpenoid molecules to enhance antibacterial properties of polymer surfaces ». Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF065.
Texte intégralRésumé :
Les huiles essentielles sont des candidates biosourcées potentielles pour être greffées sur des surfaces polymères afin de lutter contre les infections bactériennes, soit en restreignant la croissance des bactéries (effet bactériostatique), soit en tuant les cellules bactériennes (effet bactéricide). Cette thèse porte sur la modification de molécules terpénoïdes destinées à être greffées sur des surfaces polymères activées. Nous visons à greffer des molécules d’huiles essentielles modifiées sur des surfaces polymères par des liaisons covalentes fortes, facilitées par la technologie de traitement au plasma. Le citronellol (CT) et le géraniol (GR) ont été choisis pour leur activité antimicrobienne et ont été modifiés avec succès afin d’obtenir une meilleure réactivité pour la greffe sur polymère. Ils ont été transformés en CT-oxyde et GR-oxyde grâce à une méthode d’oxydation chimio-enzymatique accessible et respectueuse de l’environnement. Des tests microbiologiques ont été réalisés pour évaluer les effets antibactériens de CT et GR avant et après modification. Trois espèces bactériennes ont été utilisées: Escherichia coli, Staphylococcus aureus et Corynebacterium glutamicum. Les résultats ont montré que les effets antibactériens subsistaient après l’époxydation; les molécules testées ont démontré des activités antibactériennes en ciblant les enveloppes cellulaires bactériennes, en perturbant l’intégrité des membranes et en modifiant l’hydrophobicité. Ces actions ont conduit à l’inhibition de la croissance bactérienne ou à la mort des bactéries, comme l’ont révélé les mesures de potentiel Zeta, les images obtenues par microscopie électronique à balayage et les évaluations de l’énergie de surface. Notre étude a conclu à l’efficacité antibactérienne des CT-ox et GR-ox contre les trois souches bactériennes. En outre, ces molécules terpénoïdes modifiées présentent un potentiel de greffe sur des surfaces polymères, conférant ainsi aux polymères des propriétés antimicrobiennesEssential oils are potential biosourced candidates to be grafted on polymer surfaces to fight against bacterial infections by either restricting the growth of bacteria (bacteriostatic effect) or killing bacterial cells (bactericidal effect). This thesis deals with the modification of terpenoid molecules intended to be grafted on polymer-activated surfaces. We eager to graft modified EO molecules onto polymer surface through strong covalent bonding, facilitated by plasma treatment technology. Citronellol (CT) and geraniol (GR) were chosen for their antimicrobial activity and were successfully modified to obtain better reactive function towards polymer grafting. They were transformed into CT-oxide and GR-oxide through an accessible and green chemo enzymatic oxidation method. Microbiological tests were undertaken to estimate the antibacterial effects of CT and GR before and after modification. Three bacterial species have been used: Escherichia coli, Staphylococcus aureus and Corynebacterium glutamicum. The results showed that antibacterial effects remained after epoxidation, tested molecules exhibited antibacterial activities by targeting bacterial cell envelopes, disrupting membrane integrity, and altering hydrophobicity. These actions led to the inhibition of bacterial growth or death of the bacteria, as evidenced by Zeta Potential measurements, Scanning Electron Microscopy imaging, and surface energy assessments. Our study conclusively confirmed the antibacterial effectiveness of CT-ox and GR-ox against three bacterial strains. Furthermore, those modified terpenoid molecules have potential to graft on the polymer surface and provide polymer antimicrobial property
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Belabed, Siham. « Le greffage de cyclodextrines modifiées par traitement Corona sur matériaux cellulosiques ». Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10122/document.
Texte intégralRésumé :
Les matériaux textiles occupent une place importante dans notre quotidien. Les recherches actuelles s'orientent vers l'élaboration de matériaux à nouvelles propriétés techniques. Parmi les voies d'obtention, on peut citer le greffage de microcapsules ou de molécules cages rechargeables contenant un principe actif qui va être libéré au cours du temps donnant aux textiles de nouvelles fonctionnalités. Dans cette thèse, nous avons synthétisé des cyclodextrines originales dotées de groupements permettant leur greffage sur des fibres de coton après activation du substrat et qui conservent en partie leur capacité à inclure des principes actifs. Dans le souci d'utiliser des technologies propres et d'éviter l'utilisation de produits chimiques, notre choix s'est porté sur une activation par traitement Corona. Nous avons mis en évidence que ce traitement entraîne la formation de radicaux libres, une oxydation et un accroissement de la rugosité en surface des fibres cellulosiques. La conduite en parallèle d'expériences basées sur une activation chimique a confirmé que les radicaux libres formés au cours du traitement Corona sont impliqués dans le mécanisme de greffage de molécules allylées et notamment de la tétradécakis-(2,6-di-O-allyl)-β-cyclodextrine. Des analyses par gravimétrie, spectroscopie de photoélectrons X, thermogravimétrie et microscopie électronique à balayage ont démontré que le greffage avait bien lieu. Après greffage, la cyclodextrine conserve sa capacité à former des complexes d'inclusion notamment lorsque l'on utilise la phénolphtaléine comme molécule invitée ce qui ouvre des perspectives intéressantes pour ce travailTextiles are omnipresent in our everyday life. Research in this area tends to elaborate more sophisticated or "clever" materials i.e. confer new properties by means of innovative protocols. Among the available protocols, we can propose the grafting of microcapsules or host molecules able to guest an active substance which can be evolved. In our study, we synthesized original cyclodextrins bearing functional groups that allow their grafting on activated cotton fabrics. These entities maintain their inclusion ability. For activation purpose, we chose an "ecofriend" technology which does not require solvents, the corona discharge treatment (CDT). We evidenced that formation of free radicals, oxidation, and increase of roughness occur at the surface of cellulose during treatment. By carrying out experiments based on chemical activation, we concluded that free radicals are implied in grafting mechanism of allyl molecules and especially tetradecakis-(2,6-di-O-allyl)-β-cyclodextrin. Analysis by gravimetry, X ray photoelectron spectroscopy, thermogravimetry and scanning electon microscopy give the proof that grafting was effective. The inclusion ability of the modified β-cyclodextrins after grafting was studied with the dye extinction method determined by inclusion of phenolphthalein
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Poncin-Epaillard, Fabienne. « Etude de la polymerisation induite par plasma froid : interface plasma-polymere, greffage, degradation et modification chimique ». Le Mans, 1987. http://www.theses.fr/1987LEMA1028.
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Etude de monomeres liquides ou solides sous l'action des plasmas froids. Influence des parametres du plasma sur la vitesse de polymerisation et la structure chimique de la surface du polymere. Aux interfaces entre le plasma et le polymere, se produisent des reactions qui ont pour origine deux transferts d'energie du plasma. Le transfert indirect, attribue aux rayonnements uv-visible, provoque la polymerisation des acrylates. Le transfert direct, du au bombarbement par des especes metastables, radicaux, ions. . . Sur la surface du polymere, amorce des reactions de modification d'addition ou de terminaison
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Epaillard, Fabienne. « Etude de la polymérisation induite par plasma froid interface plasma-polymère, greffage, dégradation et modification chimique / ». Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376048298.
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Delaux, Joakim. « Activation de biopolymères par plasma atmosphérique non thermique ». Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2310.
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L'équipe de François Jérôme (IC2MP, UMR7285) a développé des procédés innovants et originaux dans les prétraitements de la biomasse lignocellulosique. Ces travaux fondamentaux sont basés sur l'utilisation de plasma atmosphérique non-thermique afin de dépolymériser des biopolymères (cellulose, amidon, inuline) de manière sélective. L'avantage de ce prétraitement physique est son absence de solvant et de catalyseur permettant ainsi de pallier les problèmes de purification ou de dilution habituellement rencontrés. On peut également citer la faible consommation énergétique. Ce prétraitement plasma permet d'accroitre l'accessibilité des biopolymères aux espèces réactives (lors d'une hydrolyse par exemple) et d'obtenir des rendements supérieurs aux procédés chimiques ou enzymatiques classiques.L'objectif de cette thèse est de comprendre quelles sont les bonnes conditions pour obtenir une cellulose moins réfractaire aux traitements chimiques et quel mécanisme est mis en jeu lors du traitement par plasma. Quels impacts ont les espèces qui interagissent avec la surface du biopolymère, comment elles diffusent au cœur des matrices polymériques ou encore quel est l'impact de la nature chimique du/des biopolymère(s) (cristallinité, type de liaisons, nature des saccharides…). Par la suite, une étude sur la réactivité de la cellulose traitée par plasma a été réalisée en se concentrant plus particulièrement sur les rendements en glucose suite à une hydrolyse acide en milieu dilué. Cela nous a permis d'évaluer l'impact des traitements physiques (plasma, broyage ou les deux) sur la réactivité de la cellulose. De plus, un panel d'analyses a été réalisé et nous a permis d'en déduire un mécanisme réactionnel possible pour le traitement de la cellulose par plasmaFrançois Jerome's team developed new processes for the pretreatment of lignocellulosic biomass. This fundamental work is based on the use of non-thermal atmospheric plasma for the deplolymerization of biopolymers (cellulose, inuline) selectively. The advantage of this physical pretreatment is the non-using of catalysis or solvent and so it's resolve the dilution problem or the purifying problem usually met. A low consummation of energy can be cited too. This pretreatment could be increase the reactivity of biopolymers (hydrolysis for example) and get a better yield than the chemical or enzymes processes.The goal of the thesis is to understand what are the good conditions to obtain a cellulose more reactive for the chemical reactions and what the mechanism for the plasma treatment are. What kind of species react with the surface of the polymers and how they enter in the bulk ? What is the role of the nature and constitution (crystallinity, different polymer, kind of link…) ? Then, a study on the reactivity of the plasma cellulose was performed and the focus was put on the yield of glucose after acid hydrolysis. Like this, we can see the influence of the physical pretreatment (plasma, milling or both) on the cellulose. At the end, a mechanism is proposed by using all the information recovered in particularly with the structural analysis
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Kacem, Imen. « Textiles à activité biologique via le greffage par plasma et l’immobilisation de molécules bioactives ». Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10020/document.
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L’intérêt des implants médicaux ne cesse de grandir et leur utilisation tend à s’étendre aux différents domaines de la chirurgie, en partie grâce à l’émergence de nouvelles techniques de modification de surface. Ainsi il est possible d’améliorer les propriétés des biomatériaux en vue d’une meilleure intégration dans les tissus vivants et prévenir les diverses complications liées à leur utilisation. Ceci permet à la fois de répondre aux attentes des chirurgiens, d’améliorer les conditions de guérison des patients suite à l’intervention, voire même d’apporter une activité thérapeutique à long terme au biomatériau en évitant la rechute, la thrombose, la restenose ou l’infection. C’est dans ce contexte que nous avons cherché à fonctionnaliser la surface de textiles en polyester (polyéthylène téréphtalate), matière très largement utilisée dans le domaine médical, par des molécules bioactives connues par leurs propriétés antibactérienne ou anti-thrombotique: le lysozyme, la gentamicine et l’héparine. L’idée développée dans ce travail de thèse fut de fixer dans un premier temps des fonctions acide carboxylique (-COOH) jouant le rôle d’«ancre» pour la fixation ultérieure des trois principes actifs. La première étape a donc consisté à greffer l’acide polyacrylique (PAA) par copolymérisation greffante assistée par traitement plasma froid, suivie dans un second temps, de la fixation des trois principes actifs, par liaisons physiques (ioniques) et/ou covalentes. L’étude a d’abord porté sur l’optimisation des paramètres de ces deux étapes du traitement via une investigation systématique et un plan d’expériences. Des techniques de caractérisations telles que la spectrophotométrie UV, l’analyse infrarouge IRTF, l’analyse thermique ATG, l’analyse par spectrométrie photoélectronique XPS, la goniométrie, la microscopie électronique à balayage MEB et des essais mécaniques ont montré l’évolution de la composition de la surface et de propriétés mécaniques des textiles au fil des différentes étapes. Des études biologiques par des tests de vitalité cellulaire, d’adhésion plaquettaire et de coagulation ainsi que différentes études microbiologiques ont pu montrer selon les différentes voies de modification choisies l’obtention de supports fonctionnalisés biocompatibles à efficacité intéressante pour des applications biomédicalesThe interest in medical implants increases and their use spreads to different surgical domains partially thanks to the new techniques of surface modification. Therefore it is possible to improve the biomaterials properties in order to solve the problems liked with their integration in the living tissues and thereby to prevent the various complications related to their use. This approach allows to respond to the surgeons expectations, to improve the curing process of the patients and even to involve long term therapeutic activities to the biomaterial, thus preventing the release of the disease (such as thrombosis, restenosis, infection). In this context, we have attempted the functionalization of the surface of a polyester fabric (polyethylene terephtalate), widely used in medical field, by three bioactive molecules: lysozyme, gentamicin and heparin known for their antimicrobial or anti thrombotic properties. The concept was to graft polyacrylic acid (PAA) by graft polymerization induced by cold plasma technique, followed by the immobilization of the above mentioned molecules through physical and covalent links. We studied all the experimental parameters involved in the different processes and followed the properties of the obtained materials through the appropriate characterizations techniques, such as spectrophotometry UV, Infrared analysis IRTF, Thermogravimetric analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), goniometry, scanning electron microscope (SEM), and mechanical tests. Finally, biological studies such as cell vitality tests, platelets adhesion test and coagulation test in addition with various microbiological essays showed the evolution of the biological properties of the materials, depending on the path of their modification resulted in the development of a novel, biocompatible functionalized supports family with very interesting and attractive efficacy for biomedical applications
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Michel, Valérie. « Modifications de surface de membranes polymères par greffage de nouveaux récepteurs induit par plasma : application au transport de métaux ». Montpellier 2, 1999. http://www.theses.fr/1999MON20127.
Texte intégralRésumé :
Ce travail decrit les modifications de surface de membranes commerciales d'ultrafiltration de polyacrylonitrile (pan) par greffage de nouveaux recepteurs induit par plasma froid puis, leur application au transport de metaux. La technique utilisee est une technique par etapes. La premiere etape consiste a exposer les membranes pan a un plasma d'helium dans le but de former des radicaux a leur surface. Puis, lors de l'exposition a l'air des membranes plasmees, les radicaux reagissent avec l'oxygene pour former des peroxydes et/ou hydroperoxydes lesquels pourront initier lors de la seconde etape, le greffage des recepteurs en solution sous l'action de la temperature. Dans un premier temps, nous nous sommes attardes sur les conditions du traitement plasma (duree, puissance, pression d'helium) conduisant au taux optimal de peroxydes et/ou hydoperoxydes sans pour autant endommager la structure poreuse des membranes pan. Puis, nous avons etudie l'influence des differents parametres intervenant lors du post-greffage des recepteurs (solvant, concentration du recepteur, duree, temperature, presence d'un inhibiteur d'hompolymerisation) afin d'optimiser la fonctionnalisation des membranes avec les differents recepteurs synthetises. Toutes les nouvelles membranes obtenues ont ete caracterisees par spectrometrie ir-atr ou raman, meb, afm, mesures des angles de contact a l'eau et mesures de la permeabilite a l'azote. Les membranes modifiees, denses a l'azote ont alors ete utilisees pour le transport de cations metalliques (na +, cu 2 +, ni 2 +, cd 2 +, pb 2 +) : un effet de facilitation, grace aux groupements pyridiniques et aux atomes d'oxygene presents dans les recepteurs greffes a la surface des membranes pan, a pu etre observe.
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Falher, Thierry. « Post-greffage de la n-vinyl-2-pyrrolidone sur un film de polypropylene modifie par un plasma froid d'azote ». Le Mans, 1996. http://www.theses.fr/1996LEMA1005.
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Jia, Zixian. « Elaboration des matériaux composites nanostructurés Ag, Au/TiO² pour la dépollution des effluents gazeux avec une activation par plasma ». Thesis, Paris 13, 2013. http://www.theses.fr/2013PA132050.
Texte intégralRésumé :
Au cours de ce travail de thèse, nous avons développé un procédé plasma-catalyse d'élimination de l'acétaldéhyde en utilisant un processus diphasique couplant un catalyseur nano-structuré et a plasma à la pression atmosphérique. L’élaboration du catalyseur nanostructuré a été d'abord étudiée. Puis la performance de dégradation du polluant a été étudiée. Les nanoparticules monodispersées (titane-oxo-alcoxy) sont générées dans le réacteur de sol-gel avec micro-mélange turbulent et déposés sur des plaques de verre ou des billes de verre comme monocouches nanostructurées. Le dépôt de l'argent et de l'or est réalisé par la réduction des ions sous l’irradiation de UV-A. La cinétique de croissance photocatalytiques et de la morphologie des nanoparticules sont étudiés expérimentalement par les méthodes MET, MEB et AFM. Il est également intéressant de discuter du mécanisme de la formation des nanoparticules et d'évaluer son efficacité quantique. Les conclusions expérimentales sont supportées théoriquement par le calcul des spectres d'absorption. Ensuite l'efficacité du processus de couplage d'une décharge à barrière diélectrique et d’un lit fluidisé d'argent et d’or nanostructurés, pour la dégradation d'un polluant modèle (acétaldéhyde CH₃CHO), est étudiée. Dans la première partie, l'efficacité du procédé plasma seul est discutée, en termes de dégradation des polluants et de production de CO et CO₂. Dans la deuxième partie, la dégradation de CH₃CHO ainsi que la production COx sont étudié en fonction du temps de réduction photocatalytique d’Ag+ et d’Au³⁺ ions, qui est liée à la masse d'argent et d’or déposée. Les voies de dégradation des polluants, notamment la chimie homogène dans la phase de plasma et la chimie hétérogène sur la surface, sont discutées. Enfin, la production des sous-produits principaux est présentées et comparées entre les catalyseurs Ag et AuDuring this Phd work, we have developed a plasma-catalytic process of acetaldehyde removal using a diphasic process coupling a nano-structured catalyst and an atmospheric pressure plasma. The elaboration of the nanoparticulate catalyst has been firstly studied. Then its performance coupling with plasma has been investigated. The monodispersed titanium-oxo-alkoxy nanoparticles are generated in the sol-gel reactor with turbulent micromixing and deposited onto glass plates or glass balls as monolayer nanocoatings. The silver and gold deposition is achieved by the ions reduction at UV-A light illumination. The photocatalytic growth kinetics and nanoparticle morphology are studied experimentally by the TEM, SEM and AFM methods. It’s also interesting to discuss the mechanism of the nanoparticles formation and evaluate its quantum efficiency. The drawn conclusions are supported theoretically through the calculation of the absorption spectra. Then the efficiency of the process coupling a dielectric barrier discharge and a fluidized nanostructured silver and gold based bed for the degradation of a model pollutant (acetaldehyde CH₃ CHO) is studied. In the first part, the efficiency of the plasma alone process is discussed, in terms of pollutant removal and CO and CO₂ production. In the second part, CH₃ CHO removal as well as COx production is studied as a function of the photocatalytic reduction time of Ag⁺ and Au³⁺ ions, which is related to the deposited silver and gold mass. The pollutant removal pathways, including homogeneous chemistry in the plasma phase and heterogeneous chemistry on the surface, are discussed. Finally, the production of main by-products is presented and compared between Ag and Au catalysts
Actes de conférences sur le sujet "Greffage par activation plasma"
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Rawat, Niharika, Ita Junkar, Metka Benčina, Tomaž Lampe, Veronika Kralj-Iglič et Aleš Iglič. « Titanium Dioxide Substrates as Sensors for Detection of Platelets and Extracellular Particles from Blood Plasma ». Dans Socratic Lectures 11, 92–101. University of Lubljana Press, 2024. http://dx.doi.org/10.55295/psl.11.2024.11.
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Biosensors are pivotal in biomedical applications, particularly for disease detection, diag-nosis, treatment, health management, and monitoring. Titanium dioxide (TiO2) is a prom-inent material for biosensors due to its biocompatibility, corrosion resistance, and availa-bility in various nanostructured forms. This study explores the interaction of platelets and extracellular vesicles (EVs) with different TiO2 surface morphologies using flow cytometry (FCM) and scanning electron microscopy (SEM). Blood plasma samples were incubated with various TiO2 surfaces to evaluate particle counts and characteristics. FCM results in-dicated a higher abundance of platelets compared to EVs, with significant fragmentation observed post-centrifugation. SEM analysis confirmed platelet activation and fragmenta-tion, with the microflowered TiO2 surface displaying fewer vesicles due to its rough to-pography. The findings suggest that while TiO2 surface structuring minimally impacts par-ticle counts, it influences platelet and EV interactions, highlighting the need for advanced detection techniques and further investigation into surface interactions. Keywords: cold gaseous plasma; atmospheric pressure plasma; plasma technology; dental medicine; extracellular vesicles, surface treatment