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Santos, T, Carvalho J, Corvo MC, Cabrita EJ, Queiroz JA, Cruz C.  2016.  L-tryptophan and dipeptide derivatives for supercoiled plasmid DNA purification. International Journal of Biological Macromolecules. : Elsevier Abstract
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dos Santos, LM, Ligabue R, Dumas A, Le Roux C, Micoud P, Meunier J-F, Martin F, Corvo M, Almeida P, Einloft S.  2018.  Waterborne polyurethane/Fe3O4-synthetic talc composites: synthesis, characterization, and magnetic properties. Polymer Bulletin. :1–16.: Springer Berlin Heidelberg AbstractWebsite

Nano-Fe3O4-synthetic talc gel was used as filler in the synthesis of waterborne polyurethane/Fe3O4-synthetic talc nanocomposites. This filler presents numerous edges (Si–O and Mg–O) and OH groups easily forming hydrogen bonds and polar interaction with water conferring hydrophilic character, consequently improving filler dispersion within a water-based matrix. Yet, the use of waterborne polyurethane (WPU) as matrix must be highlighted due to its environmentally friendly characteristics and low toxicity compared to solvent-based product. Fe3O4-synthetic talc-nanofillers were well dispersed into the polyurethane matrix even at high filler content as supported by XRD and TEM analyses. NMR indicates the interaction of filler OH groups with the matrix. For all nanocomposites, one can see a typical ferromagnetic behavior below Curie temperature (about 120 K) and a superparamagnetic behavior above this temperature. The use of Fe3O4-synthetic talc for obtaining magnetic nanocomposites resulted in improved materials with superior mechanical properties compared to solvent-based nanocomposites.

Santos, T, Carvalho J, Corvo MC, Cabrita EJ, Queiroz JA, Cruz C.  2016.  L-tryptophan and dipeptide derivatives for supercoiled plasmid DNA purification. International Journal of Biological Macromolecules. 87:385-396.: Elsevier AbstractWebsite

The present study focus on the preparation of chromatography supports for affinity-based chromatography of supercoiled plasmid purification. Three l-tryptophan based supports are prepared through immobilization on epoxy-activated Sepharose and characterized by HR-MAS NMR. The SPR is employed for a fast screening of l-tryptophan derivatives, as potential ligands for the biorecognition of supercoiled isoform, as well as, to establish the suitable experimental conditions for the chromatography. The results reveal that the overall affinity is high (KD = 10−9 and 10−8 M) and the conditions tested show that the use of HEPES 100 mM enables the separation and purification of supercoiled at T = 10 °C. The STD-NMR is performed to accomplish the epitope mapping of the 5′-mononucleotides bound to l-tryptophan derivatives supports. The data shows that the interactions between the three supports and the 5′-mononucleotides are mainly hydrophobic and π–π stacking. The chromatography experiments are performed with l-tryptophan support and plasmids pVAX-LacZ and pPH600. The supercoiled isoform separation is achieved at T = 10 °C by decreasing the concentration of (NH4)2SO4 from 2.7 to 0 M in HEPES for pVAX-LacZ and 2.65 M to 0 M in HEPES for pPH600.

Overall, l-tryptophan derivatives can be a promising strategy to purify supercoiled for pharmaceutical applications.

dos Santos, LM, Bernard FL, Polesso BB, Pinto IS, Frankenberg CC, Corvo MC, Almeida PL, Cabrita E, Menezes S, Einloft S.  2020.  Designing silica xerogels containing RTIL for CO2 capture and CO2/CH4 separation: Influence of ILs anion, cation and cation side alkyl chain length and ramification. Journal of Environmental Management. 268:110340. AbstractWebsite

CO2 separation from natural gas is considered to be a crucial strategy to mitigate global warming problems, meet product specification, pipeline specs and other application specific requirements. Silica xerogels (SX) are considered to be potential materials for CO2 capture due to their high specific surface area. Thus, a series of silica xerogels functionalized with imidazolium, phosphonium, ammonium and pyridinium-based room-temperature ionic liquids (RTILs) were synthesized. The synthesized silica xerogels were characterized by NMR, helium pycnometry, DTA-TG, BET, SEM and TEM. CO2 sorption, reusability and CO2/CH4 selectivity were assessed by the pressure-decay technique. Silica xerogels containing IL demonstrated advantages compared to RTILs used as separation solvents in CO2 capture processes including higher CO2 sorption capacity and faster sorption/desorption. Using fluorinated anion for functionalization of silica xerogels leads to a higher affinity for CO2 over CH4. The best performance was obtained by SX- [bmim] [TF2N] (223.4 mg CO2/g mg/g at 298.15 K and 20 bar). Moreover, SX- [bmim] [TF2N] showed higher CO2 sorption capacity as compared to other reported sorbents. CO2 sorption and CO2/CH4 selectivity results were submitted to an analysis of variance and the means compared using Tukey's test (5%).

dos Santos, LM, Ligabue R, Dumas A, Le Roux C, Micoud P, Meunier J-F, Martin F, Corvo M, Almeida P, Einloft S.  2017.  Waterborne polyurethane/Fe3O4-synthetic talc composites: synthesis, characterization, and magnetic properties. Polymer Bulletin. :1-16.: Springer Berlin Heidelberg AbstractWebsite

Nano-Fe3O4-synthetic talc gel was used as filler in the synthesis of waterborne polyurethane/Fe3O4-synthetic talc nanocomposites. This filler presents numerous edges (Si–O and Mg–O) and OH groups easily forming hydrogen bonds and polar interaction with water conferring hydrophilic character, consequently improving filler dispersion within a water-based matrix. Yet, the use of waterborne polyurethane (WPU) as matrix must be highlighted due to its environmentally friendly characteristics and low toxicity compared to solvent-based product. Fe3O4-synthetic talc-nanofillers were well dispersed into the polyurethane matrix even at high filler content as supported by XRD and TEM analyses. NMR indicates the interaction of filler OH groups with the matrix. For all nanocomposites, one can see a typical ferromagnetic behavior below Curie temperature (about 120 K) and a superparamagnetic behavior above this temperature. The use of Fe3O4-synthetic talc for obtaining magnetic nanocomposites resulted in improved materials with superior mechanical properties compared to solvent-based nanocomposites.

Silva, W, Zanatta M, Ferreira AS, Corvo MC, Cabrita EJ.  2020.  Revisiting Ionic Liquid Structure-Property Relationship: A Critical Analysis, {OCT}. International Journal of Molecular Sciences. 20:7745., Number {20} AbstractWebsite

{In the last few years, ionic liquids (ILs) have been the focus of extensive studies concerning the relationship between structure and properties and how this impacts their application. Despite a large number of studies, several topics remain controversial or not fully answered, such as: the existence of ion pairs, the concept of free volume and the effect of water and its implications in the modulation of ILs physicochemical properties. In this paper, we present a critical review of state-of-the-art literature regarding structure-property relationship of ILs, we re-examine analytical theories on the structure-property correlations and present new perspectives based on the existing data. The interrelation between transport properties (viscosity, diffusion, conductivity) of IL structure and free volume are analysed and discussed at a molecular level. In addition, we demonstrate how the analysis of microscopic features (particularly using NMR-derived data) can be used to explain and predict macroscopic properties, reaching new perspectives on the properties and application of ILs.}