Synthesis of Al doped ZnO nanoparticles by aqueous coprecipitation

International audienceAl-doped ZnO particles were obtained by a simple route: soda addition in aqueous cationic solution. The effects of temperature, hydrolysis duration, reagent concentration and time were investigated. A non-topotactic reaction mechanism, involving firstly the precipitation of various hydroxide compounds depending on the route (low or high pH), followed by the dissolution-recrystallization of the hydroxide species into ZnO was demonstrated. The Al concentration in the final ZnO nanopowders did not exceed 0.3 at.% which correspond to the solubility limit of Al in ZnO. The different experimental conditions allow the morphology of ZnO particles to be controlled from isotropic nanoparticles of several tens of nanometers, platelets of several hundreds of nanometers or agglomerates of needle like particles

Elastomeric cardiopatch scaffold for myocardial repair and ventricular support

[EN] OBJECTIVES: Prevention of postischaemic ventricular dilatation progressing towards pathological remodelling is necessary to decrease ventricular wall deterioration. Myocardial tissue engineering may play a therapeutic role due to its capacity to replace the extracellular matrix, thereby creating niches for cell homing. In this experimental animal study, a biomimetic cardiopatch was created with elastomeric scaffolds and nanotechnologies. METHODS: In an experimental animal study in 18 sheep, a cardiopatch was created with adipose tissue-derived progenitor cells seeded into an engineered bioimplant consisting of 3-dimensional bioabsorbable polycaprolactone scaffolds filled with a peptide hydrogel (PuraMatrix (TM)). This patch was then transplanted to cover infarcted myocardium. Non-absorbable poly(ethyl) acrylate polymer scaffolds were used as controls. RESULTS: Fifteen sheep were followed with ultrasound scans at 6 months, including echocardiography scans, tissue Doppler and spectral flow analysis and speckle-tracking imaging, which showed a reduction in longitudinal left ventricular deformation in the cardiopatch-treated group. Magnetic resonance imaging (late gadolinium enhancement) showed reduction of infarct size relative to left ventricular mass in the cardiopatch group versus the controls. Histopathological analysis at 6 months showed that the cardiopatch was fully anchored and integrated to the infarct area with minimal fibrosis interface, thereby promoting angiogenesis and migration of adipose tissue-derived progenitor cells to surrounding tissues. CONCLUSIONS: This study shows the feasibility and effectiveness of a cardiopatch grafted onto myocardial infarction scars in an experimental animal model. This treatment decreased fibrosis, limited infarct scar expansion and reduced postischaemic ventricular deformity. A capillary network developed between our scaffold and the heart. The elastomeric cardiopatch seems to have a positive impact on ventricular remodelling and performance in patients with heart failure.The RECATABI Project (Regeneration of Cardiac Tissue Assisted by Bioactive Implants) was financially supported by the 7th Framework Programme (FP7) of the European Commission. Project ID: 229239. Funded under FP7-NMP and the European Regional Development Fund (FEDER Spain).Chachques, JC.; Lila, N.; Soler Botija, C.; Martínez-Ramos, C.; Vallés Lluch, A.; Autret, G.; Perier, M.... (2020). Elastomeric cardiopatch scaffold for myocardial repair and ventricular support. European Journal of Cardio-Thoracic Surgery. 57(3):545-555. https://doi.org/10.1093/ejcts/ezz252S545555573Madonna, R., Van Laake, L. W., Botker, H. E., Davidson, S. M., De Caterina, R., Engel, F. B., … Sluijter, J. P. G. (2019). ESC Working Group on Cellular Biology of the Heart: position paper for Cardiovascular Research: tissue engineering strategies combined with cell therapies for cardiac repair in ischaemic heart disease and heart failure. Cardiovascular Research, 115(3), 488-500. doi:10.1093/cvr/cvz010Nielsen, S. H., Mouton, A. J., DeLeon-Pennell, K. Y., Genovese, F., Karsdal, M., & Lindsey, M. L. (2019). Understanding cardiac extracellular matrix remodeling to develop biomarkers of myocardial infarction outcomes. Matrix Biology, 75-76, 43-57. doi:10.1016/j.matbio.2017.12.001Spinale, F. G., Frangogiannis, N. G., Hinz, B., Holmes, J. W., Kassiri, Z., & Lindsey, M. L. (2016). Crossing Into the Next Frontier of Cardiac Extracellular Matrix Research. Circulation Research, 119(10), 1040-1045. doi:10.1161/circresaha.116.309916Chachques, J. C., Pradas, M. M., Bayes-Genis, A., & Semino, C. (2013). Creating the bioartificial myocardium for cardiac repair: challenges and clinical targets. Expert Review of Cardiovascular Therapy, 11(12), 1701-1711. doi:10.1586/14779072.2013.854165Bayés-Genís, A., Gálvez-Montón, C., & Roura, S. (2016). Cardiac Tissue Engineering. Journal of the American College of Cardiology, 68(7), 724-726. doi:10.1016/j.jacc.2016.05.055Shafy, A., Fink, T., Zachar, V., Lila, N., Carpentier, A., & Chachques, J. C. (2012). Development of cardiac support bioprostheses for ventricular restoration and myocardial regeneration. European Journal of Cardio-Thoracic Surgery, 43(6), 1211-1219. doi:10.1093/ejcts/ezs480Castells-Sala, C., Recha-Sancho, L., Llucià-Valldeperas, A., Soler-Botija, C., Bayes-Genis, A., & Semino, C. E. (2016). Three-Dimensional Cultures of Human Subcutaneous Adipose Tissue-Derived Progenitor Cells Based on RAD16-I Self-Assembling Peptide. Tissue Engineering Part C: Methods, 22(2), 113-124. doi:10.1089/ten.tec.2015.0270Martínez-Ramos, C., Rodríguez-Pérez, E., Garnes, M. P., Chachques, J. C., Moratal, D., Vallés-Lluch, A., & Monleón Pradas, M. (2014). Design and Assembly Procedures for Large-Sized Biohybrid Scaffolds as Patches for Myocardial Infarct. Tissue Engineering Part C: Methods, 20(10), 817-827. doi:10.1089/ten.tec.2013.0489Biswas, M., Sudhakar, S., Nanda, N. C., Buckberg, G., Pradhan, M., Roomi, A. U., … Houle, H. (2013). Two- and Three-Dimensional Speckle Tracking Echocardiography: Clinical Applications and Future Directions. Echocardiography, 30(1), 88-105. doi:10.1111/echo.12079Dorsey, S. M., McGarvey, J. R., Wang, H., Nikou, A., Arama, L., Koomalsingh, K. J., … Burdick, J. A. (2015). MRI evaluation of injectable hyaluronic acid-based hydrogel therapy to limit ventricular remodeling after myocardial infarction. Biomaterials, 69, 65-75. doi:10.1016/j.biomaterials.2015.08.011Chachques, J. C. (2009). Cellular cardiac regenerative therapy in which patients? Expert Review of Cardiovascular Therapy, 7(8), 911-919. doi:10.1586/erc.09.84Chachques, J. (1997). Dynamic cardiomyoplasty: clinical follow-up at 12 years. European Journal of Cardio-Thoracic Surgery, 12(4), 560-568. doi:10.1016/s1010-7940(97)00214-5Varela, C. E., Fan, Y., & Roche, E. T. (2019). Optimizing Epicardial Restraint and Reinforcement Following Myocardial Infarction: Moving Towards Localized, Biomimetic, and Multitherapeutic Options. Biomimetics, 4(1), 7. doi:10.3390/biomimetics4010007Van den Borne, S. W. M., Cleutjens, J. P. M., Hanemaaijer, R., Creemers, E. E., Smits, J. F. M., Daemen, M. J. A. P., & Blankesteijn, W. M. (2009). Increased matrix metalloproteinase-8 and -9 activity in patients with infarct rupture after myocardial infarction. Cardiovascular Pathology, 18(1), 37-43. doi:10.1016/j.carpath.2007.12.012Ducharme, A., Frantz, S., Aikawa, M., Rabkin, E., Lindsey, M., Rohde, L. E., … Lee, R. T. (2000). Targeted deletion of matrix metalloproteinase-9 attenuates left ventricular enlargement and collagen accumulation after experimental myocardial infarction. Journal of Clinical Investigation, 106(1), 55-62. doi:10.1172/jci8768Sieminski, A. L., Semino, C. E., Gong, H., & Kamm, R. D. (2008). Primary sequence of ionic self-assembling peptide gels affects endothelial cell adhesion and capillary morphogenesis. Journal of Biomedical Materials Research Part A, 87A(2), 494-504. doi:10.1002/jbm.a.31785Bagó, J. R., Soler-Botija, C., Casaní, L., Aguilar, E., Alieva, M., Rubio, N., … Blanco, J. (2013). Bioluminescence imaging of cardiomyogenic and vascular differentiation of cardiac and subcutaneous adipose tissue-derived progenitor cells in fibrin patches in a myocardium infarct model. International Journal of Cardiology, 169(4), 288-295. doi:10.1016/j.ijcard.2013.09.013Chachques, J. C., Trainini, J. C., Lago, N., Cortes-Morichetti, M., Schussler, O., & Carpentier, A. (2008). Myocardial Assistance by Grafting a New Bioartificial Upgraded Myocardium (MAGNUM Trial): Clinical Feasibility Study. The Annals of Thoracic Surgery, 85(3), 901-908. doi:10.1016/j.athoracsur.2007.10.052Lee, H., Ahn, S., Bonassar, L. J., & Kim, G. (2012). Cell(MC3T3-E1)-Printed Poly(ϵ-caprolactone)/Alginate Hybrid Scaffolds for Tissue Regeneration. Macromolecular Rapid Communications, 34(2), 142-149. doi:10.1002/marc.201200524Strub, M., Van Bellinghen, X., Fioretti, F., Bornert, F., Benkirane-Jessel, N., Idoux-Gillet, Y., … Clauss, F. (2018). Maxillary Bone Regeneration Based on Nanoreservoirs Functionalizedε-Polycaprolactone Biomembranes in a Mouse Model of Jaw Bone Lesion. BioMed Research International, 2018, 1-12. doi:10.1155/2018/7380389Rohman, G., Huot, S., Vilas-Boas, M., Radu-Bostan, G., Castner, D. G., & Migonney, V. (2015). The grafting of a thin layer of poly(sodium styrene sulfonate) onto poly(ε-caprolactone) surface can enhance fibroblast behavior. Journal of Materials Science: Materials in Medicine, 26(7). doi:10.1007/s10856-015-5539-7Spadaccio, C., Nappi, F., De Marco, F., Sedati, P., Taffon, C., Nenna, A., … Rainer, A. (2017). Implantation of a Poly-l-Lactide GCSF-Functionalized Scaffold in a Model of Chronic Myocardial Infarction. Journal of Cardiovascular Translational Research, 10(1), 47-65. doi:10.1007/s12265-016-9718-9Monnet, E., & Chachques, J. C. (2005). Animal Models of Heart Failure: What Is New? The Annals of Thoracic Surgery, 79(4), 1445-1453. doi:10.1016/j.athoracsur.2004.04.002Bellin, G., Gardin, C., Ferroni, L., Chachques, J., Rogante, M., Mitrečić, D., … Zavan, B. (2019). Exosome in Cardiovascular Diseases: A Complex World Full of Hope. Cells, 8(2), 166. doi:10.3390/cells802016

Na-Ion Batteries Based on Na-Rich Layered Oxyde and Optimised Hard Carbon: An Study of the Electrode/Electrolyte Interphase

Sodium ion batteries (NIB) represent nowadays one of the most promising « beyond Li » technologies. However, and according to recent reviews [1], the development of a true market based on NIB strongly depends on optimizing positive/negative electrode couples delivering high potentials and with a suitable electrolyte. Research carried out in the PCM2E/GREMAN laboratories is focused on the synthesis and electrochemical characterization of positive electrodes based on new materials ascribed to the Na-rich oxide family, not containing expensive and toxic ions as cobalt. In a first time, sodium half-cells with very nice capacities, close to 140 mAh/g, have been successfully prepared in our laboratories. In order to ensure capacity retention, we have also studied different electrolytes by measuring their impact on the electrode/electrolyte interphase. Spectroscopic techniques as XPS and EIS are helpful for this goal. More recently, our laboratories are focusing on the building of full cells containing such oxides against optimized hard carbon-based composites as negative electrode, with increased conductivity. In this presentation we will show the first results on these full NIBs and analyze their cycling properties by the use of different physico-chemical and electrochemical techniques.  [1] </jats:p

Ca and Co Substitutions in (Ca,Co)(OH)2 Hydroxides

International audienceAccording to DFT simulation, no mixed hydroxide containing calcium and a small divalent cation with the brucite structure is possible. This experimental study confirms that between portlandite (Ca(OH)2) and b-Co(OH)2, a solid solution does not exist. Samples have been synthesized by coprecipitation under flowing nitrogen at room temperature. However, XRD, TEM and DTA/TG analyses show that a partial solubility exists and that the substitution limit of calcium in b-Co(OH)2 is lower than 12% and lower than 7% for cobalt in Ca(OH)2. The two kinds of particles exhibit similar plate-like morphology with a size between 50 and 200 nm and a thickness of about 10 nm. The origin of such low substitution limits could be the difference in radii between calcium and cobalt generating local stresses. Substitutions by small amounts of different cations to reduce the local stresses such as Al, Sr or Cu have failed to allow improving significantly the substitution limits. An alternative synthesis route consisting in contacting the first cation oxide in a solution containing a salt of the second cation has also failed to reach a complete solid solution between portlandite and b-Co(OH)2

Dielectric Properties of Hexagonal Perovskite Ceramics Prepared by Different Routes

International audienceIn this work, four different methods, i.e. solid state reaction, citrate sol–gel process, Pechini and microwave are employed to synthesize Ba4YMn3O11.5±δ ceramics. The phase structure of the powders can be well indexed as a 12R hexagonal perovskite crystallizing in space group . The density and morphology (average grain size) of sintered samples vary with the synthesis processes. The dielectric permittivity and loss tangent of the samples have been measured in the frequency range 1 kHz–1 MHz. The results show that they are very sensitive to the synthesis process. The best properties are obtained for the sample synthetized by citrate process. This compound has a high dielectric permittivity (), which is almost frequency independent over the 100 Hz–100 kHz range from room temperature to 150 °C. This has been attributed to the IBLC mechanism. By impedance spectroscopy analysis, all the compounds were found to be electrically heterogeneous, exhibiting semiconducting grains and insulating grain boundaries. Finally, we show that the IBLC model is well adapted to the materials obtained by the modified citrate synthesis route, but not to the ones from the other routes

Low temperature synthesis of Co 3 O 4 and (Co 1− x Mn x ) 3 O 4 spinels nanoparticles

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Cyclable and non-volatile electric field control of magnetism in BiFeO 3 based magnetoelectric heterostructures

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Effect of nickel substitution on electrical and microstructural properties of CaCu 3 Ti 4 O 12 ceramic

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Existence of a solid solution from brucite to b-Co(OH)2

International audienceThis study shows that between brucite (Mg(OH)2) and β-Co(OH)2, all the compositions are possible. The solid solution Mg1−xCox(OH)2 has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg-Co mixed oxide with all possible cationic ratio

Solvent-assisted synthesis of carbon nanotubes-manganese oxide hybrid materials for high voltage aqueous supercapacitor

International audienceThis work relates to the preparation of CNT-MnO2 hybrid electrode by a simple solvent-assisted synthesis. This one-step method is also cost-effective, scalable, and addition of surfactant or other additives for carrying out the synthesis is not necessary.The effect of selected solvents (DMF vs. ethanol) on the properties and performance of the prepared materials is depicted during this work using XRD, Raman, TEM, SEM and porosity estimation by nitrogen adsorption-desorption isotherm at 77 K. The electrochemical behavior was studied using cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy in a K2SO4 aqueous electrolyte. The superior electrochemical performance of the CNT-MnO2 hybrid obtained by DMF assisted synthesis were explicated by its favorable texture and morphology. Furthermore, an asymmetric 2 V aqueous supercapacitor was assembled and tested using hybrid CNT-MnO2 and reduced graphene oxide (rGO) as positive and negative electrodes respectively. The supercapacitor showed an excellent stability under cycling (6000 cycles) with a specific energy of 14 Wh/kg at a power density of 3000 W kg−1