Why should polymer physicists study biopolymers?

Donald, Athene M.

doi:10.1002/polb.21335

Cited by 6 publications

(3 citation statements)

References 39 publications

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“…Near the isoelectric point (pI) of the protein the overall charge is close to zero therefore, repulsive electrostatic interactions between protein molecules will be minimised and their aggregation will be promoted. In particular, β-Lg aggregation close to its pI and under denaturing conditions was reported to produce particulate gels, which were composed of spherical particles (Donald, 2007).…”

Section: Effect Of Phmentioning

confidence: 99%

Characterisation of β-lactoglobulin nanoparticles and their binding to caffeine

et al. 2017

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The production of β-Lg nanoparticles by a simple heat-induced denaturation method without the need to add chemicals was performed at different conditions of pH, and temperature of denaturation. Optimum conditions were set as 0.2 % β-Lg, pH 6 and simply heating at 75°C for 45 minutes. At these conditions, a monodisperse solution with colloidal stability was obtained and the yield of aggregation was over 90%. Shape and size of nanoparticles were determined by Dynamic Light Scattering and by electron microscopy. A monodisperse particle size distribution of spherical shape particles (200nm-300nmin diameter) was obtained. The stability of the aggregates towards various types of dissociating buffers was studied. Sodium dodecyl sulphate (SDS) and urea had a strong effect on the size of the nanoparticles, while 2-Mercaptoethanol and Dithiothreitol (DTT) had no significant effect. Therefore hydrogen bonding and hydrophobic interactions were the predominant interactions responsible for the microstructure. Maximum yield of caffeine encapsulation of 13.54% was obtained at caffeine to the β-Lg molar ratio of 50:1. Rapid nanoparticle degradation and increase in polydispersity during the incubation of β-Lg nanoparticles at simulating stomach conditions was observed due to enzymatic attack. Nevertheless, little release of entrapped caffeine was noted. Total release was achieved at intestinal conditions. Finally, the adsorption of caffeine to both native and denatured -Lg followed a Langmuir adsorption isotherm model and caffeine had three times more affinity for partially denatured β-Lg in nanoparticles than for native protein.

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Section: Effect Of Phmentioning

confidence: 99%

Characterisation of β-lactoglobulin nanoparticles and their binding to caffeine

et al. 2017

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“…Polymer gels have many applications, ranging from foodstuffs , to supporting frameworks for cell growth , to dielectric elastomers . Normally soft polymer gels, those with a low polymer volume fraction, are rather brittle and cannot support large strains in either tension or compression.…”

Section: Introductionmentioning

confidence: 99%

Step-Cycle Mechanical Processing of Gels of sPP-b-EPR-b-sPP Triblock Copolymer in Mineral Oil

et al. 2010

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Gels of syndiotactic polypropylene-b-ethylene-propylene-rubber-b-syndiotactic polypropylene (sPP-EPR-sPP) were prepared by dissolving ∼6 wt % of the triblock copolymer in mineral oil at 170 °C and then cooling to room temperature in several steps to crystallize the sPP block. The gel was subjected to step-cycle processing by first extending it to a given maximum tensile strain, followed by decreasing the load to zero. The cycle was then repeated to a higher maximum strain and so on until the sample either failed or it reached an ultimate predetermined strain. The true stress and true strain ε H during each cycle were recorded, including the true strain at zero load ε H,p after each cycle that resulted from the plastic deformation of the sPP crystals in the gel. The initial Young's modulus E init and maximum tangent modulus E max in each cycle undergo dramatic changes as a function of ε H,p , with E init decreasing for ε H,p e 0.1 and then increasing slowly as ε H,p increases to 1 while E max increases rapidly over the entire range of ε H,p , resulting in a ratio of E max /E init > 1000 at the highest maximum (nominal) strain of 20. On the basis of small-angle X-ray scattering patterns from the deformed and relaxed gels, as well as on previous results on deformation of semicrystalline random copolymers by Strobl and co-workers, we propose that the initial decrease in E init with ε H,p is due to a breakup of the network of the original sPP crystal lamellae while the increase in E max with ε H,p is caused by the conversion of the sPP lamellae into fibrils of an aspect ratio that increases with further plastic deformation. The gel elastic properties can be understood as those of a short fiber composite with a highly deformable matrix. At zero stress the random copolymer midblock chains that connect the fibrils cause these to make all angles to the tensile axis (low E init ) while at the maximum strain the stiff crystalline sPP fibrils align with the tensile axis producing a strong, relatively stiff gel.

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“…The study of the processes relating polymer physics and glycobiology will have increased interest in coming years, as recent events regarding modified heparin compounds have clearly demonstrated 1. To contribute to the trend of polymer physicists working in applications of biopolymers,2 here, we present a study that may prove useful for investigations in glycobiology with the use of polymer physics models.…”

Section: Introductionmentioning

confidence: 99%

Polymer model of cancer cell adhesion to glycosaminoglycan substrates using the radius of gyration

Peramo

Meads

Dalton

et al. 2008

J of Applied Polymer Sci

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The hypothesis that the adhesion of whole cancer cells to glycosaminoglycan (GAG) substrates is a function of polysaccharide radius of gyration is presented. We use a worm-like chain (WLC) polymer model describing the global structure of the GAGs that will take into account the charge distribution and contour length of the polysaccharide implicitly in its radius of gyration to relate these parameters to cell adhesion. Specifically, we present measurements of the in vitro adhesion of cancer cells to isolated and individualized GAG substrates. We find that adhesion of the cells has a linear response with the radius of gyration and is essentially controlled by the charge per dimer. This dominating mechanism is not eliminated when the cells are subjected to resuspension in media with heparin. We then propose how these physical properties could be used to predict the preferred molecular structures of compounds for use as antimetastatic or antiinflammatory agents by comparing our results with known effective molecules.

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Why should polymer physicists study biopolymers?

Cited by 6 publications

References 39 publications

Characterisation of β-lactoglobulin nanoparticles and their binding to caffeine

Characterisation of β-lactoglobulin nanoparticles and their binding to caffeine

Step-Cycle Mechanical Processing of Gels of sPP-b-EPR-b-sPP Triblock Copolymer in Mineral Oil

Polymer model of cancer cell adhesion to glycosaminoglycan substrates using the radius of gyration

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