| 11. |
- Rasheed, Faiza, et al.
(författare)
-
Unraveling the Structural Puzzle of the Giant Glutenin Polymer-An Interplay between Protein Polymerization, Nanomorphology, and Functional Properties in Bioplastic Films
- 2018
-
Ingår i: ACS Omega. - : AMER CHEMICAL SOC. - 2470-1343. ; 3:5, s. 5584-5592
-
Tidskriftsartikel (refereegranskat)abstract
- A combination of genotype, cultivation environment, and protein separation procedure was used to modify the nanoscale morphology, polymerization, and chemical structure of glutenin proteins from wheat. A low-polymerized glutenin starting material was the key to protein-protein interactions mainly via SS cross-links during film formation, resulting in extended beta-sheet structures and propensity toward the formation of nanoscale morphologies at molecular level. The properties of glutenin bioplastic films were enhanced by the selection of a genotype with a high number of cysteine residues in its chemical structure and cultivation environment with a short grain maturation period, both contributing positively to gluten strength. Thus, a combination of factors affected the structure of glutenins in bioplastic films by forming crystalline beta-sheets and propensity toward the ordered nanostructures, thereby resulting in functional properties with high strength, stiffness, and extensibility.
|
|
| 12. |
- Agthe, Michael, et al.
(författare)
-
Following in Real Time the Two-Step Assembly of Nanoparticles into Mesocrystals in Levitating Drops
- 2016
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 16:11, s. 6838-6843
-
Tidskriftsartikel (refereegranskat)abstract
- Mesocrystals composed of crystallographically aligned nanocrystals are present in biominerals and assembled materials which show strongly directional properties of importance for mechanical protection and functional devices. Mesocrystals are commonly formed by complex biomineralization processes and can also be generated by assembly of anisotropic nanocrystals. Here, we follow the evaporation-induced assembly of maghemite nanocubes into mesocrystals in real time in levitating drops. Analysis of time-resolved small-angle X-ray scattering data and ex situ scanning electron microscopy together with interparticle potential calculations show that the substrate-free, particle-mediated crystallization process proceeds in two stages involving the formation and rapid transformation of a dense, structurally disordered phase into ordered mesocrystals. Controlling and tailoring the particle-mediated formation of mesocrystals could be utilized to assemble designed nanoparticles into new materials with unique functions.
|
|
| 13. |
- Berntsson, Oskar, et al.
(författare)
-
A setup for millisecond time-resolved X-ray solution scattering experiments at the CoSAXS beamline at the MAX IV Laboratory
- 2022
-
Ingår i: Journal of Synchrotron Radiation. - 0909-0495. ; 29, s. 555-562
-
Tidskriftsartikel (refereegranskat)abstract
- The function of biomolecules is tightly linked to their structure, and changes therein. Time-resolved X-ray solution scattering has proven a powerful technique for interrogating structural changes and signal transduction in photoreceptor proteins. However, these only represent a small fraction of the biological macromolecules of interest. More recently, laser-induced temperature jumps have been introduced as a more general means of initiating structural changes in biomolecules. Here we present the development of a setup for millisecond time-resolved X-ray solution scattering experiments at the CoSAXS beamline, primarily using infrared laser light to trigger a temperature increase, and structural changes. We present results that highlight the characteristics of this setup along with data showing structural changes in lysozyme caused by a temperature jump. Further developments and applications of the setup are also discussed.
|
|
| 14. |
- Blomfeldt, Thomas O. J., et al.
(författare)
-
Novel freeze-dried foams from glutenin- and gliadin-rich fractions
- 2012
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:16, s. 6617-6627
-
Tidskriftsartikel (refereegranskat)abstract
- This is the first study on freeze-dried foams prepared from glutenin- and gliadin-rich fractions of wheat gluten and blends thereof. It was found that the foam density and stiffness could be controlled by a suitable choice of the glutenin/gliadin ratio. The glutenin-rich samples had the highest foam densities and the density decreased with increasing gliadin content. The compression modulus also decreased with increasing gliadin content, which was explained by the decrease in foam density, a more open porosity and the more aggregated/polymerized structure in the presence of glutenin. IR and SE-HPLC revealed that the least aggregated foams were those consisting only of the gliadin-rich fraction. Confocal laser scanning microscopy revealed the presence of both HMW-glutenin and gliadin (to a certain extent probably resisting the ethanol extraction process) in the glutenin-rich foams. SAXS indicated that the gliadin-rich fraction contributed with weakly correlated protein aggregates with a characteristic distance of 40-43 Å.
|
|
| 15. |
- Ceresino, Elaine Berger, et al.
(författare)
-
Lupin Protein Isolate Structure Diversity in Frozen-Cast Foams : Effects of Transglutaminases and Edible Fats
- 2021
-
Ingår i: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 26:6
-
Tidskriftsartikel (refereegranskat)abstract
- This study addresses an innovative approach to generate aerated foods with appealing texture through the utilization of lupin protein isolate (LPI) in combination with edible fats. We show the impact of transglutaminases (TGs; SB6 and commercial), glycerol (Gly), soy lecithin (Lec) and linoleic acid (LA) on the micro- and nanostructure of health promoting solid foods created from LPI and fats blends. 3-D tomographic images of LPI with TG revealed that SB6 contributed to an exceptional bubble spatial organization. The inclusion of Gly and Lec decreased protein polymerization and also induced the formation of a porous layered material. LA promoted protein polymerization and formation of homogeneous thick layers in the LPI matrix. Thus, the LPI is a promising protein resource which when in blend with additives is able to create diverse food structures. Much focus has been placed on the great foamability of LPI and here we show the resulting microstructure of LPI foams, and how these were improved with addition of TGs. New food applications for LPI can arise with the addition of food grade dispersant Lec and essential fatty-acid LA, by improved puffiness, and their contributing as replacer of chemical leavening additives in gluten-free products.
|
|
| 16. |
- Da Silva, Laura C.E., et al.
(författare)
-
Solvent-free and biocompatible multiphased organic-inorganic hybrid nanocomposites
- 2018
-
Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 14:9, s. 1709-1718
-
Tidskriftsartikel (refereegranskat)abstract
- Biocompatible chemically cross-linked organic-inorganic (O-I) hybrid nanocomposites were developed using a new atoxic, simple and fast, solvent-free pathway. Poly(ϵ-caprolactone) (PCL) and poly(ethylene glycol) (PEG), which are both biocompatible, were used as the organic moieties (at different PCL/PEG ratios), while in situ synthesized polysilsesquioxanes made up the inorganic moiety. The O-I hybrid nanocomposites' molecular structures were characterized using solid-state 29Si NMR, TGA and ATR-IR. Results showed an unusually high condensation yield of approximately 90% and two distinct silsesquioxane structures. No traces of the remaining isocyanate groups were found. Advanced morphological characterization of the ternary O-I hybrids was performed using a combination of electron microscopy and X-ray scattering techniques such as SEM, TEM, ESI-TEM, WAXS and temperature-dependent SAXS. Results showed the occurrence of spherical nanoparticles, associated with polysilsesquioxane, and ordered network grains, associated with PCL and/or PEG chains cross-linked by silsesquioxane cages. As a consequence, a four-phased nanostructured morphology was proposed. In this model, PCL and PEG are undistinguishable, while polysilsesquioxane nanoparticles are uniformly distributed throughout a homogeneous cross-linked matrix, which shows gel-like behavior. Moreover, a mobile phase made up of unbound polymer chains occurs at the grain interface.
|
|
| 17. |
- Diuk Andrade, Fabiana, et al.
(författare)
-
An insight into molecular motions and phase composition of gliadin/glutenin glycerol blends studied by 13C solid-state and 1H time-domain NMR
- 2018
-
Ingår i: Journal of Polymer Science, Part B: Polymer Physics. - : Wiley. - 0887-6266 .- 1099-0488. ; 56:9, s. 739-750
-
Tidskriftsartikel (refereegranskat)abstract
- Monitoring of the molecular motions and secondary structures of gliadin (Gli) and glutenin (Glu) in blends with 10, 20, 30, and 40% glycerol was performed by solid-state (SS) and time domain (TD) NMR spectroscopy. Increasing the glycerol content increased the relative amount of β-sheets and disordered structures, while decreasing α-helices in Gli/Glu–glycerol blends studied by 13C CPMAS NMR. For ≥20% glycerol samples, the protein side-chain mobility increased similarly for Gli and Glu. A higher proportion of α-helices versus β-sheets was found in Gli-glycerol blends compared with Glu–glycerol blends. Glycerol acted as “immobilized” in 10–20% glycerol Gli samples and was found mainly “free” in 30 and 40% glycerol Gli/Glu samples. During temperature experiments, 30 and 40% glycerol amounts impacted the dynamic molecular behavior of the Gli and Glu proteins differently than lipids, as observed by TD-NMR. The combination of TD-NMR together with SS-NMR showed details of the dynamic molecular variations in Gli/Glu protein structure and are promising techniques to monitor the molecular dynamics of plasticized proteins.
|
|
| 18. |
- Germiniani, Luiz G.L., et al.
(författare)
-
Poly(ε-caprolactone)/cellulose nanocrystal nanocomposite mechanical reinforcement and morphology : the role of nanocrystal pre-dispersion
- 2019
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 54:1, s. 414-426
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanocrystal (CNC) incorporation in polymeric matrices is an environmentally friendly approach to mechanical reinforcement. In general, significant mechanical reinforcement can only be achieved by means of good CNC dispersion at random orientation. These primary characteristics are even more relevant for the preparation of nanocomposites based on hydrophobic matrices, such as poly(ε-caprolactone) (PCL). A straightforward approach to improve CNC dispersion in hydrophobic matrices is their surface modification. However, this extra step is usually complex and often impairs particle–particle interactions, which are also key to mechanical reinforcement. In this work, poly(ε-caprolactone)/neat cellulose nanocrystal nanocomposites were prepared by a specific procedure that combined solvent exchange and solvent casting methodologies, avoiding the use of any additives or chemical modification. These nanocomposites were investigated in terms of the CNC percolation network formation and its effect on the overall mechanical properties. The results showed that significant mechanical reinforcement was obtained, reaching a 155% Young’s modulus increase at 25 wt% CNC content. TEM showed a percolated network in the PCL/CNC25 nanocomposite. In terms of morphology and nanostructure, increasing CNC concentration also promoted a reduction in PCL spherulite size and lamellar thickness. These results pointed out to CNC preferential localization in the interfibrillar region. In conclusion, the solvent exchange methodology presented herein led to mechanically reinforced PCL/CNC nanocomposites with small crystalline domains intertwined with a percolated CNC network.
|
|
| 19. |
- Gillams, Richard J., et al.
(författare)
-
Formation of Inverse Topology Lyotropic Phases in Dioleoylphosphatidylcholine/Oleic Acid and Dioleoylphosphatidylethanolamine/Oleic Acid Binary Mixtures
- 2014
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 30:12, s. 3337-3344
-
Tidskriftsartikel (refereegranskat)abstract
- The addition of saturated fatty acids (FA) to phosphatidylcholine lipids (PC) that have saturated acyl chains has been shown to promote the formation of lyotropic liquidcrystalline phases with negative mean curvature. PC/FA mixtures may exhibit inverse bicontinuous cubic phases (Im3m, Pn3m) or inverse topology hexagonal phases (HII), depending on the length of the acyl chains/fatty acid. Here we report a detailed study of the phase behavior of binary mixtures of dioleoylphosphatidylcholine (DOPC)/oleic acid (OA) and dioleoylphosphatidylethanolamine (DOPE)/oleic acid at limiting hydration, constructed using small-angle X-ray diffraction (SAXD) data. The phase diagrams of both systems show a succession of phases with increasing negative mean curvature with increasing OA content. At high OA concentrations, we have observed the occurrence of an inverse micellar Fd3m phase in both systems. Hitherto, this phase had not been reported for phosphatidylethanolamine/fatty acid mixtures, and as such it highlights an additional route through which fatty acids may increase the propensity of bilayer lipid membranes to curve. We also propose a method that uses the temperature dependence of the lattice parameters of the HII phases to estimate the spontaneous radii of curvature (R0) of the binary mixtures and of the component lipids. Using this method, we calculated the R0 values of the complexes comprising one phospholipid molecule and two fatty acid molecules, which have been postulated to drive the formation of inverse phases in PL/FA mixtures. These are −1.8 nm (±0.4 nm) for DOPC(OA)2 and −1.1 nm (±0.1 nm) for DOPE(OA)2. R0 values estimated in this way allow the quantification of the contribution that different lipid species make to membrane curvature elastic properties and hence of their effect on the function of membrane-bound proteins.
|
|
| 20. |
- Jansson, Maria, et al.
(författare)
-
Intercalation of cationic peptides within Laponite layered clay minerals in aqueous suspensions : The effect of stoichiometry and charge distance matching
- 2019
-
Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 557, s. 767-776
-
Tidskriftsartikel (refereegranskat)abstract
- Clays can be synthesised to have specific functional properties, which have been exploited in a range of industrial processes. A key characteristic of clay is the presence of a negatively charged surface, surrounded by an oppositely charged rim. Because of that, clays are able to sequester cationic compounds resulting in the formation of ordered layered structures, known as tactoids. Recent research has highlighted the possibility of utilising clay as a drug delivery compound for cationic peptides. Here, we investigate the process of intercalation by using the highly cationic peptide deca-arginine, and the synthetic clay Laponite, in aqueous suspensions with 2.5 wt% Laponite, and varying peptide concentrations. Small-angle X-ray scattering experiments show that tactoids are formed as a function of deca-arginine concentration in the dispersion, and for an excess of peptide, i.e. above a matched charge-ratio between the peptide and clay, the growth of the tactoids is limited, resulting in tactoidal dissolution. Zeta-potential measurements confirm that the observed dissolution is caused by overcharging of the platelets. By employing coarse-grained molecular dynamics simulations based on the continuum model, we are able to predict the tactoid formation, the growth, and the dissolution, in agreement with experimental results. We propose that the present simulation method can be a useful tool to tune peptide and clay characteristics to optimise and determine the extent of intercalation by cationic peptides of therapeutic interest.
|
|
