Browsing by Keyword "Physical and Theoretical Chemistry"

Now showing 1 - 20 of 70
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    29Si chemical shift anisotropies in hydrated calcium silicates: A computational study
    (2013-04-25) Rejmak, Pawel; Dolado, Jorge S.; Stott, Malcolm J.; Ayuela, Andrés; Tecnalia Research & Innovation
    The 29Si chemical shift anisotropies are investigated for calcium silicate hydrates. The focus is on the naturally occurring minerals, jennite and 14 Å tobermorite and models derived from them to simulate calcium-silicate-hydrate gel, the main component of Portland cement. Our theoretical results show that the analysis of anisotropy and asymmetry of the 29Si chemical shift discriminates between different Si types, even if their isotropic chemical shifts are similar. Terminal and pairing silica tetrahedra are clearly distinguished and the chemical shift anisotropies set apart the Si tetrahedra that are hydroxylated. The chemical shift anisotropy measurements, although more challenging than the usual isotropic chemical shift experiments, could greatly improve our knowledge of not only cement materials, but silicate hydrates, in general.
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    29Si NMR in cement: A theoretical study on calcium silicate hydrates
    (2012-05-03) Rejmak, Pawel; Dolado, Jorge S.; Stott, Malcolm J.; Ayuela, Andrés; Tecnalia Research & Innovation
    The NMR spectra of 29Si in cement-based materials are studied through calculations of the isotropic shielding of silicon atoms within the density functional theory. We focus on the main component of cement, the calcium-silicate-hydrate gel, using widely accepted models based on the observed structures of jennite and tobermorite minerals. The results show that the 29Si chemical shifts are dependent not only on the degree of condensation of the (SiO 4) units, as commonly assumed, but also on the local arrangement of the charge compensating H and Ca cations. We find that the NMR spectra for models of the calcium-silicate-hydrate gel based on tobermorite are in better agreement with experiment than those for jennite-based models.
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    Aluminum incorporation to dreierketten silicate chains
    (2009-03-05) Manzano, H.; Dolado, J. S.; Ayuela, A.; Tecnalia Research & Innovation
    This work explores, from a theoretical viewpoint, the aluminum incorporation into silicate chains with dreierketten conformation relevant in the cementitious calcium-silicate-hydrate (C-S-H) gel and in other minerals, such as wollastonite and hillebrandite. To this end, we have investigated by means of ab initio calculations both the stability and the formation of aluminosilicate chains. Our results show that only certain aluminosilicate chains are stable, namely, those whose tetrahedra length m obey the m ) 3n - 1 rule with n ) 1, 2, 3,..., in agreement with experiments. Moreover, our detailed analyses explain why Al ions prefer the bridging sites and introduce new insights on the growth process.
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    Ammonium polyphosphate-melamine synergies in thermal degradation and smoke toxicity of flexible polyurethane foams
    (2023-08) Eceiza, I.; Aguirresarobe, R.; Barrio, A.; Fernández-Berridi, M. J.; Irusta, L.; BIOECONOMÍA Y CO2
    Polyurethane (PUR) foams can lead to fatal fires in the presence of an ignition and oxygen source. Obviously, the problem is not the mere loss of PUR foams properties but essentially, the smoke and toxic gases which are the main factors responsible for fire hazards. This paper reports on the main approaches taken to improve the smoke evolution and toxicity of isophorone diisocyanate (IPDI) based PUR foams which are the incorporation of ammonium polyphosphate (APP), melamine (M) and its combinations as additive flame retardants (FRs). In order to better understand the fire behavior, the influence of incorporated FR on the thermal degradation mechanism was also analyzed by means of thermogravimetry coupled to infrared spectroscopy (TGA-FTIR). In addition, foams were characterized in terms of smoke evolution and toxicity of released gases both asphyxiant and irritant using a smoke density chamber coupled to infrared spectroscopy (NBS-FTIR). Data showed that the mixture of APP and M in different amounts reduced the smoke generation and the concentration of harmful gases, underlying a synergetic effect for the combination of both flame-retardants.
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    Attrition-resistant membranes for fluidized-bed membrane reactors: Double-skin membranes: Double-skin membranes
    (2018-10-01) Arratibel, Alba; Medrano, Jose Antonio; Melendez, Jon; Pacheco Tanaka, D. Alfredo; van Sint Annaland, Martin; Gallucci, Fausto; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; Tecnalia Research & Innovation
    Pd-Ag supported membranes have been prepared by coating a ceramic interdiffusion barrier onto a Hastelloy X (0.2 µm media grade) porous support followed by deposition of the hydrogen selective Pd-Ag (4–5 µm) layer by electroless plating. To one of the membranes an additional porous Al2O3-YSZ layer (protective layer with 50 wt% of YSZ) was deposited by dip-coating followed by calcination at 550 °C on top of the Pd-Ag layer, and this membrane is referred to as a double-skin membrane. Both membranes were integrated at the same time in a single reactor in order to assess and compare the performance of both membranes under identical conditions. The membranes have first been tested in an empty reactor with pure gases (H2 and N2) and afterwards in the presence of a catalyst (rhodium onto promoted alumina) fluidized in the bubbling regime. The membranes immersed in the bubbling bed were tested at 400 °C and 500 °C for 115 and 500 h, respectively. The effect of the protective layer on the permeation properties and stability of the membranes were studied. The double-skinned membraned showed a H2 permeance of 1.55·10−6 mol m−2 s−1 Pa−1 at 500 °C and 4 bar of pressure difference with an ideal perm-selectivity virtually infinite before incorporation of particles. This selectivity did not decay during the long term test under fluidization with catalyst particles.
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    Benchmark of ReaxFF force field for subcritical and supercritical water
    (2018-06-21) Manzano, Hegoi; Zhang, Weiwei; Raju, Muralikrishna; Dolado, Jorge S.; López-Arbeloa, Iñigo; Van Duin, Adri C.T.; Tecnalia Research & Innovation
    Water in the subcritical and supercritical states has remarkable properties that make it an excellent solvent for oxidation of hazardous chemicals, waste separation, and green synthesis. Molecular simulations are a valuable complement to experiments in order to understand and improve the relevant sub- and super-critical reaction mechanisms. Since water molecules under these conditions can act not only as a solvent but also as a reactant, dissociative force fields are especially interesting to investigate these processes. In this work, we evaluate the capacity of the ReaxFF force field to reproduce the microstructure, hydrogen bonding, dielectric constant, diffusion, and proton transfer of sub- and super-critical water. Our results indicate that ReaxFF is able to simulate water properties in these states in very good quantitative agreement with the existing experimental data, with the exception of the static dielectric constant that is reproduced only qualitatively.
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    A brief review on industrial alternatives for the manufacturing of glycerol carbonate, a green chemical
    (2012-03-16) Ochoa-Gómez, José R.; Gómez-Jiménez-Aberasturi, Olga; Ramírez-López, Camilo; Belsué, Mikel; Tecnalia Research & Innovation; BIOECONOMÍA Y CO2
    Glycerol carbonate is one the glycerol derivatives which attracts attention for industrial applications. This review compares strategies for its synthesis, and their analyses lead to the conclusion that (indirect) procedures starting from glycerol- and/or CO 2-derivatives are the most attractive. These are described and compared, taking criteria of industrial feasibility into account. As a result, the transesterification of dimethyl carbonate or ethylene carbonate with glycerol using uncalcined CaO as catalyst appears to be currently the most suitable industrial process. Finally, potential applications of glycerol carbonate as a multifunctional compound are exemplified.
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    Brownian cluster dynamics with short range patchy interactions: Its application to polymers and step-growth polymerization
    (2014-07-14) Prabhu, A.; Babu, S. B.; Dolado, J. S.; Gimel, J. C.; Tecnalia Research & Innovation
    We present a novel simulation technique derived from Brownian cluster dynamics used so far to study the isotropic colloidal aggregation. It now implements the classical Kern-Frenkel potential to describe patchy interactions between particles. This technique gives access to static properties, dynamics and kinetics of the system, even far from the equilibrium. Particle thermal motions are modeled using billions of independent small random translations and rotations, constrained by the excluded volume and the connectivity. This algorithm, applied to a single polymer chain leads to correct static and dynamic properties, in the framework where hydrodynamic interactions are ignored. By varying patch angles, various local chain flexibilities can be obtained. We have used this new algorithm to model step-growth polymerization under various solvent qualities. The polymerization reaction is modeled by an irreversible aggregation between patches while an isotropic finite square-well potential is superimposed to mimic the solvent quality. In bad solvent conditions, a competition between a phase separation (due to the isotropic interaction) and polymerization (due to patches) occurs. Surprisingly, an arrested network with a very peculiar structure appears. It is made of strands and nodes. Strands gather few stretched chains that dip into entangled globular nodes. These nodes act as reticulation points between the strands. The system is kinetically driven and we observe a trapped arrested structure. That demonstrates one of the strengths of this new simulation technique. It can give valuable insights about mechanisms that could be involved in the formation of stranded gels.
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    Cause of the fragile-to-strong transition observed in water confined in C-S-H gel
    (2013-10-28) Monasterio, Manuel; Jansson, Helén; Gaitero, Juan J.; Dolado, Jorge S.; Cerveny, Silvina; Tecnalia Research & Innovation; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN
    In this study, the rotational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel with a water content of 22 wt.% was studied by broadband dielectric spectroscopy in broad temperature (110-300 K) and frequency (10-1-108 Hz) ranges. The C-S-H gel was used as a 3D confining system for investigating the possible existence of a fragile-to-strong transition for water around 220 K. Such transition was observed at 220 K in a previous study [Y. Zhang, M. Lagi, F. Ridi, E. Fratini, P. Baglioni, E. Mamontov and S. H. Chen, J. Phys.: Condens. Matter 20, 502101 (2008)] on a similar system, and it was there associated with a hidden critical point of bulk water. However, based on the experimental results presented here, there is no sign of a fragile-to-strong transition for water confined in C-S-H gel. Instead, the fragile-to-strong transition can be explained by a merging of two different relaxation processes at about 220 K.
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    CFD Modelling and Comparison among DifferentConfigurations of Parallel Plates Iron Electrowinning Cells
    (2009-10) Serna, M.; SG
    Within the ULCOS project, a pilot cell for iron electrowinning is being designed. Electrical energy is used to transform iron ore particles (hematite) suspended in a sodium hydroxide solution into iron metal and oxygen. The work developed by Labein-Tecnalia is focused on the study of the fluid flow for different electrolytic cell configurations to get knowledge of the interaction between the oxygen bubbles generated during the process and the electrolyte flow. The numerical algorithm used is the finite volume used in the commercial Computational Fluid Dynamics code FLUENT. The work developed is focused on vertical and horizontal parallel plates configurations, to analyze the removal of oxygen bubbles from the gap between anode and cathode, and the access of iron ore particles to the cathode. A user subroutine has been developed for the CFD code to compute the mass flow rate of oxygen bubbles generated at the anode, as a function of the local current density. A methodology has been developed to analyze the accessibility of the iron ore particles to the cathode. The knowledge obtained from this work has helped for the design of the pilot cell within the ULCOS project.
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    Computational and Experimental Evaluation of the Immune Response of Neoantigens for Personalized Vaccine Design
    (2023-05) Malaina, Iker; Gonzalez-Melero, Lorena; Martínez, Luis; Salvador, Aiala; Sanchez-Diez, Ana; Asumendi, Aintzane; Margareto, Javier; Carrasco-Pujante, Jose; Legarreta, Leire; García, María Asunción; Pérez-Pinilla, Martín Blas; Izu, Rosa; Martínez de la Fuente, Ildefonso; Igartua, Manoli; Alonso, Santos; Hernandez, Rosa Maria; Boyano, María Dolores; Genética
    In the last few years, the importance of neoantigens in the development of personalized antitumor vaccines has increased remarkably. In order to study whether bioinformatic tools are effective in detecting neoantigens that generate an immune response, DNA samples from patients with cutaneous melanoma in different stages were obtained, resulting in a total of 6048 potential neoantigens gathered. Thereafter, the immunological responses generated by some of those neoantigens ex vivo were tested, using a vaccine designed by a new optimization approach and encapsulated in nanoparticles. Our bioinformatic analysis indicated that no differences were found between the number of neoantigens and that of non-mutated sequences detected as potential binders by IEDB tools. However, those tools were able to highlight neoantigens over non-mutated peptides in HLA-II recognition (p-value 0.03). However, neither HLA-I binding affinity (p-value 0.08) nor Class I immunogenicity values (p-value 0.96) indicated significant differences for the latter parameters. Subsequently, the new vaccine, using aggregative functions and combinatorial optimization, was designed. The six best neoantigens were selected and formulated into two nanoparticles, with which the immune response ex vivo was evaluated, demonstrating a specific activation of the immune response. This study reinforces the use of bioinformatic tools in vaccine development, as their usefulness is proven both in silico and ex vivo.
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    Correlating gas permeability and morphology of bio-based polyether-block-amide copolymer membranes by IR nanospectroscopy
    (2024-08) David, Oana; Etxeberria Benavides, Miren; Amenabar Altuna, Iban; Fernandez Carretero, Francisco Jose; Diaz De Guereñu Zabarte, Maria del Mar; Flat, Jean Jaques; Pineau, Quentin; Goikoetxea Larruskain, Monika; Hillenbrand, Rainer; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; TECNOLOGÍAS DE HIDRÓGENO
    The gas permeability of polymer membranes is determined by their nanoscale morphology, which strongly depends on the membrane fabrication. Here, we demonstrate how the correlation between gas permeability and fabrication-dependent nanoscale morphology of polymer membranes can be elucidated by infrared (IR) nanospectroscopy based on elastic IR scattering at an atomic force microscope tip. Specifically, we fabricated membranes of PEBAX® RNEW – a bio-based polyether-block-amide copolymer – by solvent casting and extrusion, achieving unprecedented CO2 permeability and CO2/N2 selectivity for the solvent-cast membranes. For the extruded membranes, however, we found an about 50 % reduced CO2 permeability, which could not be explained by differential scanning calorimetry and conventional IR spectroscopy. In contrast, IR nanospectroscopy revealed a highly crystalline polyether oxide (PEO) surface layer on the extruded membranes, not observed for the solvent-cast membranes. Annealing of the extruded membranes at 110 °C transformed the crystalline into amorphous PEO layers, as confirmed by IR nanospectroscopy, yielding a gas permeability close to that of the solvent-cast membranes. We thus attribute the dramatic gas reduction of the extruded membranes to their highly crystalline surface layers. Generally, studying polymer morphology by IR nanospectroscopy provides valuable information for better understanding the local gas permeability properties of polymer membranes.
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    Description of hypoeutectic Al-Si-Cu alloys based on their known chemical compositions
    (2013-09) Djurdjevic, M. B.; Vicario, I.; PROMETAL
    The modeling of casting processes has remained a topic of active interest for several decades, and the availability of numerous software packages on the market is a good indication of the interest that the casting industry has in this field. Most of the data used in these software packages are directly read or estimated from the binary or multi-component phase diagrams. Unfortunately, except for binary diagrams, many of ternary or higher order phase diagrams are still not accurate enough. Having in mind that most of the aluminum binary systems are very well established, it has been tried to transfer multi-component system into one well known Al-Xi pseudo binary system (in this case the Al-Si phase diagram was chosen as a reference system). The new Silicon Equivalency (SiEQ) algorithm expresses the amounts of major and minor alloying elements in the aluminum melts through an "equivalent" amount of silicon. Such a system could be used to calculate several thermo-physical and solidification characteristics of multi component as cast aluminum alloys. This provides to the model the capacity to predict the solidification characteristics of cast parts, where cooling rates are slow and the solidification process has to be known in great detail in order to avoid quality problems in the casting. This work demonstrates how the SiEQ algorithm can be used to calculate the characteristic solidification temperatures of the multicomponent Al-Si alloys as well as their latent heats and growth restriction factor. Statistical analysis of the results obtained for a wide range of alloy chemical compositions shows a very good correlation with the experimental data and the SiEQ calculations. The same mathematical approach might be applied for other metallic systems such as iron and magnesium, using carbon equivalency for ferrous systems and aluminum equivalency for magnesium multi-component alloys.
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    Development of Pd-based double-skinned membranes for hydrogen production in fluidized bed membrane reactors
    (2018-03-15) Arratibel, Alba; Pacheco Tanaka, Alfredo; Laso, Iker; van Sint Annaland, Martin; Gallucci, Fausto; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
    This paper reports the preparation and performance characterization of new PdAg supported membranes with a porous protecting layer to protect the membrane surface from particles in a fluidized bed membrane reactor. Supported membranes with a selective layer of 1 µm and a protective layer have been prepared. Outstanding H2 permeance (5·10−6 mol m−2 s−1 Pa−1) and H2/N2 perm-selectivity (over 25,000) were measured at 400 °C and 1 bar of pressure difference. One membrane has been tested for more than 750 h in the presence of fluidized glass beads showing a decay in the perm-selectivity to approximately 5000, mainly due to sealing leakage. However, the protective layer was removed during this long-term test. Another membrane has been tested for more than 2000 h in a fluidized bed membrane reactor with a Rh reforming catalyst supported on promoted alumina in the bubbling fluidization regime. During tests with binary mixtures mass transfer limitations toward the membrane were observed due to large H2 permeance of the membranes.
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    Direct patterning of polymer optical periodic nanostructures on CYTOP for visible light waveguiding
    (2018-08) Diez, M.; Raimbault, V.; Joly, S.; Oyhenart, L.; Doucet, J. B.; Obieta, I.; Dejous, C.; Bechou, L.; Tecnalia Research & Innovation
    Optical waveguides and grating couplers based on polymer nanostructures are now considered as promising technologies for integrated biophotonic sensing systems. Commonly, structuration and patterning of polymers at the submicron scale requires the use of time and cost-consuming equipments such as electron beam lithography. Direct patterning of high refractive index polymer devices on CYTOP is now achievable and provides symmetric waveguides with top water-like claddings. In addition, transparency of polymers makes them suitable for operation in the visible range, being of major interest for biophotonic applications. In this paper, we report on the fabrication process of polymer submicronic single-mode waveguides on CYTOP for visible light operation. Sub-wavelength grating couplers with a pitch lower than 300 nm were fabricated to couple the input light into a 350 nm square cross-section waveguide. The whole device is imprinted in a single step using soft stamp lithography with a minimal residual layer. Finally, optical characterizations demonstrate a state-of-the-art transmission efficiency (around 1.5%) at the selected operating wavelength of 507 nm for different coupling angles in good agreement with simulations.
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    Effect of Au addition on hydrogen permeation and the resistance to H2S on Pd-Ag alloy membranes
    (2017) Melendez, Jon; de Nooijer, Niek; Coenen, Kai; Fernandez, Ekain; Viviente, Jose Luis; van Sint Annaland, Martin; Arias, P. L.; Tanaka, D. A.Pacheco; Gallucci, Fausto; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS
    In order to make a detailed comparison between Pd-Ag and Pd-Ag-Au membranes according to their H2 permeation properties and sulfide resistance Au was deposited by the electroless plating (ELP) technique onto one half of Pd-Ag membranes. Membranes' thicknesses are ranged between 2.45 and 3.13 µm. Permeation tests have been carried out from 400 to 600 °C under single gas conditions. The Pd91.7Ag4.8Au3.5 membrane has shown a H2 permeance of 4.71·10−3 mol s−1 m−2 Pa0.5 at 600 °C, which is one of the highest values ever reported in the literature, where the Pd-Ag-Au membranes have exhibited higher hydrogen permeation rates compared to their respective Pd-Ag membranes above 550 °C. The H2 permeation properties have been determined in terms of the degree of H2S inhibition, up to 17 ppm, and subsequent H2 flux recovery rate. Pd-Ag membranes alloyed with gold resisted 12.5 h of H2S exposure showing recovery rates of 85% and 83% for Pd91.5Ag4.7Au3.8 and Pd90.5Ag4.6Au4.9 membranes, respectively, whereas the hydrogen flux of non-gold membranes decreased below detectable values. H2/N2 ideal perm-selectivity of the Pd-Ag membrane was reduced to 18 after H2S tests (starting from > 1308) while Pd-Ag-Au membranes showed a better resistance to sulfur with H2/N2 selectivity values of 793 and 121 (starting from > 4115 and > 2557 respectively). No evidence of the formation of a crystalline sulfide phase on the Pd-Ag-Au alloy membrane surfaces was found in the XRD patterns after H2S exposure and also XPS characterization did not show important changes in the composition before and after the H2S exposure tests. However, SEM images showed a decrease in the thickness of the Pd-Ag membrane and signs of corrosion and roughening on its surface, while gold-alloyed membranes did not show any damage.
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    Effect of hydration on the dielectric properties of C-S-H gel
    (2011-01-21) Cerveny, Silvina; Arrese-Igor, Silvia; Dolado, Jorge S.; Gaitero, Juan J.; Alegra, Angel; Colmenero, Juan; Tecnalia Research & Innovation; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN
    The behavior of water dynamics confined in hydrated calcium silicate hydrate (C-S-H) gel has been investigated using broadband dielectric spectroscopy (BDS; 10-2-106 Hz) in the low-temperature range (110-250 K). Different water contents in C-S-H gel were explored (from 6 to 15 wt) where water remains amorphous for all the studied temperatures. Three relaxation processes were found by BDS (labeled 1 to 3 from the fastest to the slowest), two of them reported here for the first time. We show that a strong change in the dielectric relaxation of C-S-H gel occurs with increasing hydration, especially at a hydration level in which a monolayer of water around the basic units of cement materials is predicted by different structural models. Below this hydration level both processes 2 and 3 have an Arrhenius temperature dependence. However, at higher hydration level, a non-Arrhenius behavior temperature dependence for process 3 over the whole accessible temperature range and, a crossover from low-temperature Arrhenius to high-temperature non-Arrhenius behavior for process 2 are observed. Characteristics of these processes will be discussed in this work.
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    Effect of the catalyst system on the reactivity of a polyurethane resin system for RTM manufacturing of structural composites
    (2022-03) Echeverria-Altuna, Oihane; Ollo, Olatz; Calvo-Correas, Tamara; Harismendy, Isabel; Eceiza, Arantxa; Tecnalia Research & Innovation; POLIMEROS
    The high versatility of polyurethanes (PU’s) is encouraging the development of new formulations for new appli cations, like their use as a matrix for structural composites. PU’s based technology offers some advantages, such as fatigue resistance and fast curing cycles. However, their high reactivity hinders some manufacturing processes like Resin Transfer Moulding (RTM). This work aimed to achieve a PU resin (PUR) formulation with the required latency and reactivity for the RTM. For this purpose, different catalytic systems based on an epoxide and LiCl were investigated. The reactivity of the systems was evaluated through Differential Scanning Calorimetry (DSC) and rheology tests, and the curing reaction and viscosity were modelled. Furthermore, the RTM process of a representative composite part was simulated. Results demon strated the processability improvements when the LiCl was incorporated into the isocyanate component of the formulation combined with a monool or a diol. It was observed that these combinations contribute to the encapsulation of the LiCl between the as formed urethane groups by hydrogen bonding, providing the desired latency and acting as a delayed action catalyst. Once the reaction started and the encapsulation was deactivated, an alkoxide was formed to act as a catalyst. En capsulation was more effective with the diol, providing a higher latency.
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    Effect of the thermal level on the viability of microencapsulated living cells dehydrated by near fluidizing microwave drying
    (2021) Mardaras, Janire; Lombraña, José Ignacio; Villarán, María Carmen; Alimentación Sostenible
    Alginate microcapsules containing cell yeasts of the species Saccharomyces cerivisae, were studied to improve the protection of cell activity during drying. Dehydration is a common operation to stabilize microencapsulated microorganisms. Here, a promising process using microwaves on a particle bed under near fluidizing conditions (NFMD) was proposed. The dehydration of microcapsules by NFMD allows performing dehydration employing lower temperatures with high survival levels of dried microorganism cells and a high quality end product. Different thermal gradients and processing temperatures of NFMD were analyzed to select the most adequate operating strategy. The obtained results were compared to those obtained by freeze-drying, assumed as reference quality drying process. The results showed that the encapsulation system, joined with the selection of favorable conditions during dehydration by NFMD, allows a post drying viability higher than 90%, with an adequate control of the process temperature. To obtain the best results regarding both, the duration of drying and quality, product temperatures of about 30 °C in the microcapsules and 5–20 °C in the air are recommended.
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    Effects of Human and Porcine Adipose Extracellular Matrices Decellularized by Enzymatic or Chemical Methods on Macrophage Polarization and Immunocompetence
    (2021-04-08) Cicuéndez, Mónica; Casarrubios, Laura; Feito, María José; Madarieta, Iratxe; Garcia-Urkia, Nerea; Murua, Olatz; Olalde, Beatriz; Briz, Nerea; Diez-Orejas, Rosalía; Portolés, María Teresa; Biomateriales; SG
    The decellularized extracellular matrix (ECM) obtained from human and porcine adipose tissue (AT) is currently used to prepare regenerative medicine bio-scaffolds. However, the influence of these natural biomaterials on host immune response is not yet deeply understood. Since macrophages play a key role in the inflammation/healing processes due to their high functional plasticity between M1 and M2 phenotypes, the evaluation of their response to decellularized ECM is mandatory. It is also necessary to analyze the immunocompetence of macrophages after contact with decellularized ECM materials to assess their functional role in a possible infection scenario. In this work, we studied the effect of four decellularized adipose matrices (DAMs) obtained from human and porcine AT by enzymatic or chemical methods on macrophage phenotypes and fungal phagocytosis. First, a thorough biochemical characterization of these biomaterials by quantification of remnant DNA, lipids, and proteins was performed, thus indicating the efficiency and reliability of both methods. The proteomic analysis evidenced that some proteins are differentially preserved depending on both the AT origin and the decellularization method employed. After exposure to the four DAMs, specific markers of M1 proinflammatory and M2 anti-inflammatory macrophages were analyzed. Porcine DAMs favor the M2 phenotype, independently of the decellularization method employed. Finally, a sensitive fungal phagocytosis assay allowed us to relate the macrophage phagocytosis capability with specific proteins differentially preserved in certain DAMs. The results obtained in this study highlight the close relationship between the ECM biochemical composition and the macrophage’s functional role.