The Experts below are selected from a list of 2502 Experts worldwide ranked by ideXlab platform
Ali Khademhosseini - One of the best experts on this subject based on the ideXlab platform.
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photocrosslinkable Kappa Carrageenan hydrogels for tissue engineering applications
Advanced Healthcare Materials, 2013Co-Authors: Silvia M Mihaila, Manuela E Gomes, Ali Khademhosseini, Akhilesh K Gaharwar, Rui L Reis, Alexandra P MarquesAbstract:Kappa Carrageenan (κ-CA) is a natural-origin polymer that closely mimics the glycosaminoglycan structure, one of the most important constituents of native tissues extracellular matrix. Previously, it has been shown that κ-CA can crosslink via ionic interactions rendering strong, but brittle hydrogels. In this study, we introduce photocrosslinkable methacrylate moieties on the κ-CA backbone to create physically and chemically crosslinked hydrogels highlighting their use in the context of tissue engineering. By varying the degree of methacrylation, the effect on hydrogel crosslinking was investigated in terms of hydration degree, dissolution profiles, morphological, mechanical, and rheological properties. Furthermore, the viability of fibroblast cells cultured inside the photocrosslinked hydrogels was investigated. The combination of chemical and physical crosslinking procedures enables the formation of hydrogels with highly versatile physical and chemical properties, while maintaining the viability of encapsulated cells. To our best knowledge, this is the first study reporting the synthesis of photocrosslinkable κ-CA with controllable compressive moduli, swelling ratios and pore size distributions. Moreover, by micromolding approaches, spatially controlled geometries and cell distribution patterns could be obtained, thus enabling the development of cell-material platforms that can be applied and tailored to a broad range of tissue engineering strategies.
Joao Maia - One of the best experts on this subject based on the ideXlab platform.
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phase separation rheology and microstructure of pea protein Kappa Carrageenan mixtures
Food Hydrocolloids, 2007Co-Authors: R.m. Musampa, M.m. Alves, Joao MaiaAbstract:Abstract Due to their interest in food industry, mixed systems of globular proteins and polysaccharides have been the subject of growing interest in recent years. In the particular case of this work, the focus is on mixtures of pea-protein–Kappa-Carrageenan. Phase diagrams of pea protein and κ-Carrageenan mixtures have been established at pH 7 above the isoelectric point (IEP) of the protein, 60 °C and two different ionic strengths (0.05 and 0.2 M). These systems led to phase separation probably arised by the depletion–flocculation mechanism. Under the same conditions, rheology and microstructure by confocal laser scanning microscopy (CLSM) of these systems in the mono and biphasic regions have been investigated. CLSM showed the formation of pea protein aggregates network in presence of κ-Carrageenan. Marked differences between mixtures in two-phase region and one component solutions were also evidenced in the rheological properties, with the behaviour being governed by the continuous protein-enriched phase.
Jinming Song - One of the best experts on this subject based on the ideXlab platform.
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enhanced immunostimulatory and antitumor activity of different derivatives of κ Carrageenan oligosaccharides from Kappaphycus striatum
Journal of Applied Phycology, 2011Co-Authors: Huamao Yuan, Jinming Song, Song LiuAbstract:Chemical modification of carbohydrates can lead to differences in their biological activities. We previously showed that Kappa-Carrageenan oligosaccharides from Kappaphycus striatum have antitumor and immunomodulation effects on S180-bearing mice. In this study, we tested the hypothesis that different chemical modifications of Carrageenan oligosaccharides enhance their activities. The mice inoculated with S180 cell suspension were treated p.o. with Carrageenan oligosaccharides and their sulfated, acetylated, and phosphorylated derivatives (50, 100, and 200 mu g g(-1)) for 14 days. Transplantable tumor inhibition rate and macrophage phagocytosis, quantitative hemolysis of sheep red blood cells, lymphocyte proliferation, the activity of natural killer cells, production of interleukin-2, and tumor necrosis factor-alpha were also analyzed. As expected, treatment with different Kappa-Carrageenan oligosaccharides derivatives resulted in an increase in tumor inhibition rate and macrophage phagocytosis and cellular immunity, especially on spleen lymphocyte proliferation. The sulfated derivative at the dose 200 mu g g(-1) per day showed the highest antitumor activity with the 54.12% tumor weight inhibition and elicited an increase in nature killer cells activity up to 76.1% on S180-bearing mice, which were both significantly higher than the unmodified oligosaccharides. It suggested that chemical modification (especially sulfation) of Carrageenan oligosaccharides can enhance their antitumor effect and boost their antitumor immunity.
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preparation structural characterization and in vitro antitumor activity of Kappa Carrageenan oligosaccharide fraction from Kappaphycus striatum
Journal of Applied Phycology, 2005Co-Authors: Huamao Yuan, Jinming SongAbstract:Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of Kappa-Carrageenan from Kappaphycus striatum to compare the antitumor activity with Carrageenan polysaccharides. Oligosaccharide fractions were isolated by gel permeation chromatography and the structure of fraction 1 (F1) was studied by using negative-ion electrospray ionization-mass spectrometry (ESI-MS), and 1H and 13C-NMR spectrometry. The in vitro antitumor effects in three human neoplastic cell lines (KB, BGC, and Hela) of polysaccharides and F1 were investigated. The bioassay results showed that F1 exhibited relatively higher antitumor activity against the three cancer cells than polysaccharides.
Norziah Mohd Hani - One of the best experts on this subject based on the ideXlab platform.
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Characterization of edible packaging films based on semi-refined Kappa-Carrageenan plasticized with glycerol and sorbitol
Food Hydrocolloids, 2017Co-Authors: Abdulaal Farhan, Norziah Mohd HaniAbstract:Semi-refined Kappa-Carrageenan (SRC) based edible films plasticized with glycerol or sorbitol at 20, 25 and 30% (w/w) were prepared and characterized. SRC films containing plasticizers had higher tensile strength and elongation at break than the control (unplasticized) SRC film. Increased moisture content, water solubility and water vapor permeability were found in films plasticized with 25–30% of glycerol and 30% of sorbitol as compared to the control SRC film. Water sorption kinetics indicated that all plasticized films reached the equilibrium rate. Films were more transparent and their seal strength increased significantly, whilst, their oil permeability was reduced when the plasticizers concentration increased from 20 to 30%. Films plasticized with sorbitol were more effective oxygen barriers than films plasticized with glycerol. Scanning electron microscopy and atomic force microscopy showed that SRC films plasticized with sorbitol were more homogeneous and smoother than the control SRC film. This study showed that the inexpensive SRC is a promising packaging material and has good potential to be used as an alternative polysaccharide material for the production of edible biodegradable packaging films with improved mechanical and barrier properties.
Huamao Yuan - One of the best experts on this subject based on the ideXlab platform.
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enhanced immunostimulatory and antitumor activity of different derivatives of κ Carrageenan oligosaccharides from Kappaphycus striatum
Journal of Applied Phycology, 2011Co-Authors: Huamao Yuan, Jinming Song, Song LiuAbstract:Chemical modification of carbohydrates can lead to differences in their biological activities. We previously showed that Kappa-Carrageenan oligosaccharides from Kappaphycus striatum have antitumor and immunomodulation effects on S180-bearing mice. In this study, we tested the hypothesis that different chemical modifications of Carrageenan oligosaccharides enhance their activities. The mice inoculated with S180 cell suspension were treated p.o. with Carrageenan oligosaccharides and their sulfated, acetylated, and phosphorylated derivatives (50, 100, and 200 mu g g(-1)) for 14 days. Transplantable tumor inhibition rate and macrophage phagocytosis, quantitative hemolysis of sheep red blood cells, lymphocyte proliferation, the activity of natural killer cells, production of interleukin-2, and tumor necrosis factor-alpha were also analyzed. As expected, treatment with different Kappa-Carrageenan oligosaccharides derivatives resulted in an increase in tumor inhibition rate and macrophage phagocytosis and cellular immunity, especially on spleen lymphocyte proliferation. The sulfated derivative at the dose 200 mu g g(-1) per day showed the highest antitumor activity with the 54.12% tumor weight inhibition and elicited an increase in nature killer cells activity up to 76.1% on S180-bearing mice, which were both significantly higher than the unmodified oligosaccharides. It suggested that chemical modification (especially sulfation) of Carrageenan oligosaccharides can enhance their antitumor effect and boost their antitumor immunity.
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preparation structural characterization and in vitro antitumor activity of Kappa Carrageenan oligosaccharide fraction from Kappaphycus striatum
Journal of Applied Phycology, 2005Co-Authors: Huamao Yuan, Jinming SongAbstract:Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of Kappa-Carrageenan from Kappaphycus striatum to compare the antitumor activity with Carrageenan polysaccharides. Oligosaccharide fractions were isolated by gel permeation chromatography and the structure of fraction 1 (F1) was studied by using negative-ion electrospray ionization-mass spectrometry (ESI-MS), and 1H and 13C-NMR spectrometry. The in vitro antitumor effects in three human neoplastic cell lines (KB, BGC, and Hela) of polysaccharides and F1 were investigated. The bioassay results showed that F1 exhibited relatively higher antitumor activity against the three cancer cells than polysaccharides.
