WorldWideScience

Sample records for alginates

  1. Bioacetylation of Seaweed Alginate

    OpenAIRE

    Lee, J W; Day, D F

    1995-01-01

    Seaweed alginate was acetylated by intact, resting cells of Pseudomonas syringae ATCC 19304. Maximum acetylation of this polymer occurred at a pH of 6.0 and a temperature of 25 deg C. Aeration and gluconic acid were required for an optimal reaction. A reactor which contained carbon-immobilized cells was constructed to continuously acetylate alginate. The maximal yield of acetylation was about 90%, and the half-life of this system was 6.5 days.

  2. Preparation methods of alginate nanoparticles

    NARCIS (Netherlands)

    Paques, J.P.; Linden, van der E.; Rijn, van C.J.M.; Sagis, L.M.C.

    2014-01-01

    This article reviews available methods for the formation of alginate nano-aggregates, nanocapsules and nanospheres. Primarily, alginate nanoparticles are being prepared by two methods. In the “complexation method”, complex formation on the interface of an oil droplet is used to form alginate nanocap

  3. 3D Cell Culture in Alginate Hydrogels

    Directory of Open Access Journals (Sweden)

    Therese Andersen

    2015-03-01

    Full Text Available This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent, and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.

  4. Alginate impressions: A practical perspective

    OpenAIRE

    Nandini, V Vidyashree; Venkatesh, K Vijay; Nair, K. Chandrasekharan

    2008-01-01

    The choice of an impression material for a particular situation depends on the treatment being provided, operator preference, and so on. Even with the introduction of more advanced and more accurate rubber base impression materials, irreversible hydrocolloid impression materials have stood the test of time. This article gives a detailed perspective of how best to make alginate impressions.

  5. Engineering alginate as bioink for bioprinting.

    Science.gov (United States)

    Jia, Jia; Richards, Dylan J; Pollard, Samuel; Tan, Yu; Rodriguez, Joshua; Visconti, Richard P; Trusk, Thomas C; Yost, Michael J; Yao, Hai; Markwald, Roger R; Mei, Ying

    2014-10-01

    Recent advances in three-dimensional (3-D) printing offer an excellent opportunity to address critical challenges faced by current tissue engineering approaches. Alginate hydrogels have been used extensively as bioinks for 3-D bioprinting. However, most previous research has focused on native alginates with limited degradation. The application of oxidized alginates with controlled degradation in bioprinting has not been explored. Here, a collection of 30 different alginate hydrogels with varied oxidation percentages and concentrations was prepared to develop a bioink platform that can be applied to a multitude of tissue engineering applications. The authors systematically investigated the effects of two key material properties (i.e. viscosity and density) of alginate solutions on their printabilities to identify a suitable range of material properties of alginates to be applied to bioprinting. Further, four alginate solutions with varied biodegradability were printed with human adipose-derived stem cells (hADSCs) into lattice-structured, cell-laden hydrogels with high accuracy. Notably, these alginate-based bioinks were shown to be capable of modulating proliferation and spreading of hADSCs without affecting the structure integrity of the lattice structures (except the highly degradable one) after 8days in culture. This research lays a foundation for the development of alginate-based bioink for tissue-specific tissue engineering applications. PMID:24998183

  6. Alginate cryogel based glucose biosensor

    Science.gov (United States)

    Fatoni, Amin; Windy Dwiasi, Dian; Hermawan, Dadan

    2016-02-01

    Cryogel is macroporous structure provides a large surface area for biomolecule immobilization. In this work, an alginate cryogel based biosensor was developed to detect glucose. The cryogel was prepared using alginate cross-linked by calcium chloride under sub-zero temperature. This porous structure was growth in a 100 μL micropipette tip with a glucose oxidase enzyme entrapped inside the cryogel. The glucose detection was based on the colour change of redox indicator, potassium permanganate, by the hydrogen peroxide resulted from the conversion of glucose. The result showed a porous structure of alginate cryogel with pores diameter of 20-50 μm. The developed glucose biosensor was showed a linear response in the glucose detection from 1.0 to 5.0 mM with a regression of y = 0.01x+0.02 and R2 of 0.994. Furthermore, the glucose biosensor was showed a high operational stability up to 10 times of uninterrupted glucose detections.

  7. Radiation degradation of alginate and some results of biological effect of degraded alginate on plants

    International Nuclear Information System (INIS)

    Radiation degradation yields (Gd) of alginate in aqueous solution with different concentration were determined by viscometry method. The relationship between Gd and the alginate concentration was found out as: Gd=33.5 x C-0.68, with C% (w/v) and dry alginate referred to C=100%. An empirical equation for preparing degraded alginate with the desired low viscometry average molecular weight (Mv) by radiation was proposed. Alginate extracted directly horn seaweed'Sagassum, degraded by radiation was used for field experiments and results of the biological effect on plants (tea, carrot, chrysanthemum) were presented. (author)

  8. Radiation degradation of alginate and some results of biological effect of degraded alginate on plants

    Energy Technology Data Exchange (ETDEWEB)

    Hien, N.Q.; Hai, L.; Luan, L.Q.; Hanh, T.T. [Nuclear Research Institute, Dalat (Viet Nam); Nagasawa, Naotsugu; Yoshii, Fumio; Makuuchi, Keizo; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Radiation degradation yields (Gd) of alginate in aqueous solution with different concentration were determined by viscometry method. The relationship between Gd and the alginate concentration was found out as: Gd=33.5 x C{sup -0.68}, with C% (w/v) and dry alginate referred to C=100%. An empirical equation for preparing degraded alginate with the desired low viscometry average molecular weight (Mv) by radiation was proposed. Alginate extracted directly horn seaweed'Sagassum, degraded by radiation was used for field experiments and results of the biological effect on plants (tea, carrot, chrysanthemum) were presented. (author)

  9. Characterization of alginate lyase activity on liquid, gelled, and complexed states of alginate.

    Science.gov (United States)

    Breguet, Véronique; von Stockar, Urs; Marison, Ian W

    2007-01-01

    A study of alginate lyase was carried out to determine if this enzyme could be used to remove alginate present in the core of alginate/poly-L-lysine (AG/PLL) microcapsules in order to maximize cell growth and colonization. A complete kinetic study was undertaken, which indicated an optimal activity of the enzyme at pH 7-8, 50 degrees C, in the presence of Ca2+. The buffer, not the ionic strength, influenced the alginate degradation rate. Alginate lyase was also shown to be active on gelled forms of alginate, as well as on the AG/PLL complex constituting the membrane of microcapsules. Batch cultures of CHO cells in the presence of alginate showed a decrease of the growth rate by a factor of 2, although the main metabolic flux rates were not modified. The addition of alginate lyase to cell culture medium increased the doubling time 5-7-fold and decreased the protein production rate, although cell viability was not affected. The addition of enzyme to medium containing alginate did not improve growth conditions. This suggests that alginate lyase is probably not suitable for hydrolysis of microcapsules in the presence of cells, in order to achieve high cell density and high productivity. However, the high activity may be useful for releasing cells from alginate beads or AG/PLL microcapsules. PMID:17691813

  10. Technological Advance for Alginate Production in Mexico

    Directory of Open Access Journals (Sweden)

    Hernández-Carmona G.

    2012-04-01

    Full Text Available Alginates are polysaccharides extracted from brown seaweeds. They are used in food industry, pharmaceutical, textile, among other, because of their properties to give high viscous solution and gel forming. This review describes the optimized process at pilot plant level for alginate production. The process includes washing the algae with HCl at pH 4, extraction of the alginate in Na2CO3 solution at pH 10 and heating to 80oC, dilution of the paste and filtrate with a vacuum rotary filter. Alginate precipitation is carried out by adding CaCl2 filtration. The fibers obtained are treated with HCl to obtain alginic acid. The product is neutralized with Na2CO3 to obtain sodium alginate. The product is dried with hot air, milled, and screened at different mesh sizes. We described the different products obtained and their physical and chemical properties. Finally, costs and barriers found that limit the alginate production at commercial level in Mexico are discussed, including the lack of the industrial design, the international cost of the alginates, the policy to give the seaweeds beds concessions, and the role of the investors.

  11. Radiation degradation of alginate and chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Naotsugu; Mitomo, Hiroshi [Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co{sup 60} gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 10{sup 5} for 0 kGy to 6 x 10{sup 3} for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  12. Radiation degradation of alginate and chitosan

    International Nuclear Information System (INIS)

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co60 gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 105 for 0 kGy to 6 x 103 for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  13. Technological Advance for Alginate Production in Mexico

    OpenAIRE

    Hernández-Carmona G.; Rodríguez-Montesinos Y.E.; Arvizu-Higuera D.L.; Reyes-Tisnado R.; Murillo-Álvarez J.I.; Muñoz-Ochoa M.

    2012-01-01

    Alginates are polysaccharides extracted from brown seaweeds. They are used in food industry, pharmaceutical, textile, among other, because of their properties to give high viscous solution and gel forming. This review describes the optimized process at pilot plant level for alginate production. The process includes washing the algae with HCl at pH 4, extraction of the alginate in Na2CO3 solution at pH 10 and heating to 80oC, dilution of the paste and filtrate with a vacuum rotary filter. Algi...

  14. Trivalent chromium sorption on alginate beads

    OpenAIRE

    Araújo, M. Manuela; Teixeira, J.A.

    1997-01-01

    The applicability of trivalent chromium removal from aqueous solutions using calcium alginate beads was studied. The equilibrium isotherms were plotted at two temperatures. The relationship between the chromium sorbed and the calcium released was determined as well as the effect of alginate amount and initial pH on the equilibrium results. Chromium sorption kinetics were evaluated as a function of chromium initial concentration and temperature. Transport properties of trival...

  15. Alginate polyelectrolyte ionotropic gels: Pt. 15

    International Nuclear Information System (INIS)

    The heterogeneous equilibrium for exchange of UO22+ counter-ions in uranyl alginate exchange resin by H+ ions has been investigated using titrimetric and spectrophotometric techniques. The thermodynamic equilibrium constant was found to be 15.51 ± 0.33 at 25oC. The electrical conductivity of uranyl alginate in the form of circular discs has been examined as a function of temperature. The Arrhenius plot of log δ versus 1/T showed a complicated behaviour where three regions of conduction were separated by two distinct transition zones. This behaviour was interpreted by the transfer of electrons from alginate to the cross-linked uranyl ion with formation of free radicals and uranium ions of lower oxidation states in a sequence, followed by dimerization of these radicals in the final stages. The X-ray diffraction pattern indicated that the uranyl alginate complex is amorphous in nature. Infrared absorption spectra indicated the presence of UO22+ chelated to the alginate macromolecular chains, and displayed γaCO2- and γsCO2- in the ranges of 1591 and 1410 cm-1 respectively. Two geometrical structures for chelation of UO22+ with the functional groups of alginate macromolecules have been suggested. (author)

  16. Freeze-thaw induced gelation of alginates.

    Science.gov (United States)

    Zhao, Ying; Shen, Wei; Chen, Zhigang; Wu, Tao

    2016-09-01

    Adding divalent ions or lowering pH below the pKa values of alginate monomers are common ways in preparing alginate gels. Herein a new way of preparing alginate gels using freeze-thaw technique is described. Solvent crystallization during freezing drove the polymers to associate into certain structures that became the junction zones of hydrogels after thawing. It enabled the preparation of alginate gels at pH 4.0 and 3.5, two pH at which the gel could not be formed previously. At pH 3.0 where alginate gel could be formed initially, applying freeze-thaw treatment increased the gel storage modulus almost 100 times. The formation of hydrogels and the resulting gel properties, such as dynamic moduli and gel syneresis were influenced by the pH values, number of freeze-thaw cycles, alginate concentrations, and ionic strengths. The obtained hydrogels were soft and demonstrated a melting behavior upon storage, which may find novel applications in the biomedical industry. PMID:27185114

  17. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles.

    Science.gov (United States)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-12-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %. PMID:26745977

  18. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles

    Science.gov (United States)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-01-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %.

  19. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  20. PLGA/alginate composite microspheres for hydrophilic protein delivery

    International Nuclear Information System (INIS)

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility

  1. Enzymatic Hydrolysis of Alginate to Produce Oligosaccharides by a New Purified Endo-Type Alginate Lyase

    Science.gov (United States)

    Zhu, Benwei; Chen, Meijuan; Yin, Heng; Du, Yuguang; Ning, Limin

    2016-01-01

    Enzymatic hydrolysis of sodium alginate to produce alginate oligosaccharides has drawn increasing attention due to its advantages of containing a wild reaction condition, excellent gel properties and specific products easy for purification. However, the efficient commercial enzyme tools are rarely available. A new alginate lyase with high activity (24,038 U/mg) has been purified from a newly isolated marine strain, Cellulophaga sp. NJ-1. The enzyme was most active at 50 °C and pH 8.0 and maintained stability at a broad pH range (6.0–10.0) and temperature below 40 °C. It had broad substrate specificity toward sodium alginate, heteropolymeric MG blocks (polyMG), homopolymeric M blocks (polyM) and homopolymeric G blocks (polyG), and possessed higher affinity toward polyG (15.63 mM) as well as polyMG (23.90 mM) than polyM (53.61 mM) and sodium alginate (27.21 mM). The TLC and MS spectroscopy analysis of degradation products suggested that it completely hydrolyzed sodium alginate into oligosaccharides of low degrees of polymerization (DPs). The excellent properties would make it a promising tool for full use of sodium alginate to produce oligosaccharides. PMID:27275826

  2. 21 CFR 184.1610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... control agents. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  3. 21 CFR 184.1011 - Alginic acid.

    Science.gov (United States)

    2010-04-01

    ... specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 13, which is incorporated by reference. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  4. Radiation protection by ascorbic acid in sodium alginate solutions

    International Nuclear Information System (INIS)

    Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of 60 Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

  5. Radiation protection by ascorbic acid in sodium alginate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Aliste, A.J.; Mastro, N.L. Del [Center of Radiation Technology, IPEN/CNEN/SP, University City, 05508-000 Sao Paulo (Brazil)]. E-mail: ajaliste@ipen.br

    2004-07-01

    Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of {sup 60} Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

  6. Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

    OpenAIRE

    Yang, Yu-Tsai; Di Pasqua, Anthony J.; He, Weiling; Tsai, Tsuimin; Sueda, Katsuhiko; Zhang, Yong; Jay, Michael

    2012-01-01

    A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA pentaethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ~1.6 mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91....

  7. Diffusivity of Cu2+ in calcium alginate gel beads: recalculation.

    Science.gov (United States)

    Lewandowski, Z; Roe, F

    1994-01-20

    Calculations of the diffusivity of Cu(2+) in calcium alginate gel beads using the shrinking core model were checked by us. Corrected results are reported here. Diffusivity was still found to increase with increasing alginate concentration, but at a lower rate than reported in the cited paper. The diffusivity increased by a factor of 2 over the range of alginate concentrations studied rather than 10. The original data is included with sample calculations. PMID:18615614

  8. Comparative characterization of three bacterial exo-type alginate lyases.

    Science.gov (United States)

    Hirayama, Makoto; Hashimoto, Wataru; Murata, Kousaku; Kawai, Shigeyuki

    2016-05-01

    Alginate, a major acidic polysaccharide in brown macroalgae, has attracted attention as a carbon source for production of ethanol and other chemical compounds. Alginate is monomerized by exo-type alginate lyase into an unsaturated uronate; thus, this enzyme is critical for the saccharification and utilization of alginate. Although several exo-type alginate lyases have been characterized independently, their activities were not assayed under the same conditions or using the same unit definition, making it difficult to compare enzymatic properties or to select the most suitable enzyme for saccharification of alginate. In this study, we characterized the three bacterial exo-type alginate lyases under the same conditions: A1-IV of Sphingomonas sp. strain A1, Atu3025 of Agrobacterium tumefaciens, and Alg17c of Saccharophagus degradans. A1-IV had the highest specific activity as well as the highest productivity of uronate, whereas Alg17c had the lowest activity and productivity. Only dialyzed Atu3025 and Alg17c were tolerant to freezing. Alg17c exhibited a remarkable halotolerance, which may be advantageous for monomerization of alginate from marine brown algae. Thus, each enzyme exhibited particular desirable and undesirable properties. Our results should facilitate further utilization of the promising polysaccharide alginate. PMID:26827758

  9. THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

    Institute of Scientific and Technical Information of China (English)

    于建; 夏延致

    2009-01-01

    Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during ...

  10. Microencapsulation of probiotics using sodium alginate

    Directory of Open Access Journals (Sweden)

    Mariana de Araújo Etchepare

    2015-07-01

    Full Text Available The consumption of probiotics is constantly growing due to the numerous benefits conferred on the health of consumers. In this context, Microencapsulation is a technology that favors the viability of probiotic cultures in food products, mainly by the properties of protection against adverse environmental conditions and controlled release. Currently there are different procedures for microencapsulation using polymers of various types of natural and synthetic origin. The use of sodium alginate polymers is one of the largest potential application in the encapsulation of probiotics because of their versatility, biocompatibility and toxicity exemption. The aim of this review is to present viable encapsulation techniques of probiotics with alginate, emphasizing the internal ionic gelation and external ionic gelation, with the possibility of applying, as well as promising for improving these techniques.

  11. Biological properties of photocrosslinked alginate microcapsules.

    Science.gov (United States)

    Shen, Feng; Li, Anna Aihua; Cornelius, Rena M; Cirone, Pasquale; Childs, Ronald F; Brash, John L; Chang, Patricia L

    2005-11-01

    An alternative form of gene therapy using recombinant cell lines delivering therapeutic products encapsulated in alginate hydrogel has proven effective in treating many murine models. The lack of long-term capsule stability has led to a new strategy to reinforce the microcapsules with a photopolymerized interpenetrating covalent network of N-vinylpyrrolidone (NVP) and sodium acrylate. Here the properties for potential application in gene therapy are reported. In assessing potential toxicity of the unpolymerized residues, HPLC showed that even after 1 week of washing, no toxic monomers could be detected. Their ability to sustain cell growth was monitored with growth of the encapsulated cells in vitro and in vivo. Although the initial photopolymerization caused significant cell damage, the cells were able to recover normal growth rates thereafter. After implanting into mice, the NVP-modified capsules showed a high level of biocompatibility as measured by hematological and biochemical functional tests. There was also no difference in the amount and type of plasma proteins adsorbing to the NVP-modified and the classical alginate capsules, thus indicating their similar biological compatibility. Both in vitro and in vivo tests confirmed that the NVP-modified capsules were more resistant to osmotic stress than the alginate microcapsules. Furthermore, when applied to the treatment of a murine model of human cancer by delivering encapsulated cells secreting angiostatin, the NVP-modified microcapsules suppressed tumor growth as successfully as the regular alginate microcapsules. In conclusion, the covalently modified microcapsules have shown a high level of biocompatibility, safety, increase in stability, and clinical efficacy for use as immunoisolation devices in gene therapy. PMID:16035031

  12. Alginate-Collagen Fibril Composite Hydrogel

    OpenAIRE

    Mahmoud Baniasadi; Majid Minary-Jolandan

    2015-01-01

    We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM)-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of th...

  13. Alginate-Collagen Fibril Composite Hydrogel

    Directory of Open Access Journals (Sweden)

    Mahmoud Baniasadi

    2015-02-01

    Full Text Available We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  14. Alginate and alginate/gelatin microspheres for human adipose-derived stem cell encapsulation and differentiation

    International Nuclear Information System (INIS)

    Human adipose-derived stem cells (hADSC) encapsulated in alginate and alginate/gelatin microspheres with adjustable properties were fabricated via an improved microsphere generating device. The mechanism of the device, porous property, swelling behavior of the microspheres and hADSC proliferation as well as adipogenic differentiation were studied extensively. Microspheres with high-ratio evenly distributed adipocytes could be obtained by utilizing the proper matrix material and manufacturing parameters. The adipocyte/hADSC microspheres were a sound in vitro mimicking of a natural fat lobule and therefore a good candidate for adipose tissue engineering and regenerative medicine. (paper)

  15. Alginate and alginate/gelatin microspheres for human adipose-derived stem cell encapsulation and differentiation.

    Science.gov (United States)

    Yao, Rui; Zhang, Renji; Luan, Jie; Lin, Feng

    2012-06-01

    Human adipose-derived stem cells (hADSC) encapsulated in alginate and alginate/gelatin microspheres with adjustable properties were fabricated via an improved microsphere generating device. The mechanism of the device, porous property, swelling behavior of the microspheres and hADSC proliferation as well as adipogenic differentiation were studied extensively. Microspheres with high-ratio evenly distributed adipocytes could be obtained by utilizing the proper matrix material and manufacturing parameters. The adipocyte/hADSC microspheres were a sound in vitro mimicking of a natural fat lobule and therefore a good candidate for adipose tissue engineering and regenerative medicine. PMID:22556122

  16. Imaging contrast effects in alginate microbeads containing trapped emulsion droplets.

    Science.gov (United States)

    Hester-Reilly, Holly J; Shapley, Nina C

    2007-09-01

    This study focuses on spherical microparticles made of cross-linked alginate gel and microcapsules composed of an oil-in-water emulsion where the continuous aqueous phase is cross-linked into an alginate gel matrix. We have investigated the use of these easily manufactured microbeads as contrast agents for the study of the flow properties of fluids using nuclear magnetic resonance imaging. Results demonstrate that combined spin-spin (T(2)) relaxation and diffusion contrast in proton NMR imaging can be used to distinguish among rigid polymer particles, plain alginate beads, and alginate emulsion beads. Multi-echo CPMG spin-echo imaging indicates that the average spin-lattice (T(1)) and spin-spin (T(2)) relaxation times of the plain alginate and alginate emulsion beads are comparable. Meanwhile, diffusion-weighted imaging produces sharp contrast between the two types of alginate beads, due to restricted diffusion inside the embedded oil droplets of the alginate emulsion beads. While the signal obtained from most materials is severely attenuated under applied diffusion gradients, the alginate emulsion beads maintain signal strength. The alginate emulsion beads were added to a suspension and imaged in an abrupt, annular expansion flow. The emulsion beads could be clearly distinguished from the surrounding suspending fluid and rigid polystyrene particles, through either T(2) relaxation or diffusion contrast. Such a capability allows future use of the alginate emulsion beads as tracer particles and as one particle type among many in a multimodal suspension where detailed concentration profiles or particle size separation must be quantified during flow. PMID:17600742

  17. Synthesis and uranium adsorption behavior of alginate-based adsorbents

    International Nuclear Information System (INIS)

    The crosslinked microspheres of alginate were synthesized by inverse suspension polymerization, and the effect of the concentration of sodium alginate solution and stirring speed on the formation of microsphere was studied. Biopolymeric adsorbents with amidocyanogen were synthesized based on alginate polymeric matrixes by chemical modification. The adsorbents were characterized by FTIR and determination of ammonio content. When the concentration of sodium alginate solution was 3%-4% and stirring speed was 250-300 r/min, the crosslinked microsphere had regular morphology and high mechanical strength. Uranium can be removed effectively from low concentration uranium solutions by the alginate-based adsorbent (SATT) modified with triethylenetetreamine, and the removal rate was more than 92%. The adsorbent was expected to use for wastewater treatment in uranium hydrometallurgy. (authors)

  18. Effects of added oligoguluronate on mechanical properties of Ca - alginate - oligoguluronate hydrogels depend on chain length of the alginate.

    Science.gov (United States)

    Padoł, Anna Maria; Draget, Kurt Ingar; Stokke, Bjørn Torger

    2016-08-20

    The effect of adding shorter alginate fragments highly enriched in α-l-guluronic acid (oligoG) on the Young's modulus of the Ca-induced alginate hydrogels were determined using nanoindentation. Ca-alginate gels using two low and one high molecular weight alginate, with increasing amount of added oligoG, were prepared at constant 20mM total Ca(2+) by in situ release of the cation. Differences in the effect on the mechanical properties of increasing amount of oligoG to the various alginate samples were attributed to their different capability to support network connectivity by junction zone formation. Upon decreasing the fractional Ca-saturation of all the α-l-guluronic acid residues (G) present, Fsat, by increasing the oligoG concentration, the lower molecular weight alginates displayed the largest reduction in Young's modulus. This was suggested to be due to the few sequences of α-l-guluronic acid residues making up potential zones engaging in network connectivity of this alginate. Similar trends were observed for a low molecular weight alginate with larger fraction of G. The higher molecular weight sample displayed less reduction of Young's modulus associated with increasing concentration of oligoG. The consequences of reduction in effective, mean junction zone functionality and associated increase in sol fraction with added oligoG on the elastic properties thus depend on the chain length of the alginates. These finding suggest that effects of added oligoG on Ca-induced alginate gelation should connect the effect on junction zone formation to those mediating network connectivity. PMID:27178929

  19. Molecular engineering of manipulated alginate-based polyurethanes.

    Science.gov (United States)

    Daemi, Hamed; Barikani, Mehdi

    2014-11-01

    The novel soluble alginate-based polyurethanes in organic solvents were synthesized by the reaction of NCO-terminated prepolymers and tributylammonium alginate (TBA-Alg) for the first time. The chemical structures of synthesized polyurethanes were characterized using FTIR, (1)H NMR and TGA. The reaction completion was confirmed by disappearing of NCO band in FTIR spectra. Furthermore, a peak at 4.71 ppm and some small peaks at a range of 4.12-4.37 ppm in the (1)H NMR of alginate-based polyurethanes were assigned to the backbone of alginate. The results of both FTIR and (1)H NMR were remarkably confirmed by TGA data. The ionic nature of polyurethane backbone not only affects on thermal properties of samples, but it also changes the chemically-bonded alginate morphology. Both polyether and polyester based non-ionic polyurethanes extended by TBA-Alg illustrated the distinct alginate, whereas those ionomers extended by alginate were appeared as the continuous systems at nanoscale. PMID:25129793

  20. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    International Nuclear Information System (INIS)

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid–base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for 1H, and 31P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min

  1. Alginate-Casein Microspheres as Bioactive Vehicles for Nutrients

    Institute of Scientific and Technical Information of China (English)

    何志敏; 张茜青; 齐崴; 黄仁亮; 苏荣欣

    2015-01-01

    The aim of this work was to develop an alginate-casein composite microsphere as a bioactive vehicle for oral administration of nutrients by a simple extrusion dripping method. Riboflavin was selected as a model drug, and the microencapsulation efficiency was raised to 97.94%after optimizing the preparation conditions by response surface methodology. In vitro release studies showed that riboflavin was released completely from alginate-casein microspheres in simulated intestinal fluids. Meanwhile, the morphology, structure and interaction between alginate and casein were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra.

  2. Growth-promotion of plants with depolymerized alginates by irradiation

    Science.gov (United States)

    Hien, Nguyen Quoc; Nagasawa, Naotsugu; Tham, Le Xuan; Yoshii, Fumio; Dang, Vo Huy; Mitomo, Hiroshi; Makuuchi, Keizo; Kume, Tamikazu

    2000-07-01

    Alginate has been degraded by gamma-ray irradiation from a Co-60 source in liquid state (aqueous solution) and in solid state (powder form). The irradiated alginate with a molecular weight less than 10 4 shows a strong effect on the growth-promotion of rice and peanut. Low concentration of degraded alginate from 4% solution irradiated at 100 kGy is effective for the growth-promotion of plants and the suitable concentrations are ca 50 ppm for rice and ca 100 ppm for peanut.

  3. Novel alginate matrix for tissue engineering: selective substitution ofmannuronic acid residues in alginate with bioactive peptides and the use of these polymers as scaffolds for cells

    OpenAIRE

    Karstensen, Kristin

    2010-01-01

    Alginate is a naturally occurring biopolymer that forms gels in the presence of divalent ions.It is a polysaccharide which functions as a structural component in marine brown algae and some bacteria. Alginate forms hydrogels by ionic cross-linking at very mild (physiological) conditions allowing immobilization in alginate to be carried out at cell suitable conditions.By entrapping therapeutic cells in alginate gels they can be protected from the host immune system upon transplantation, render...

  4. Novel Alginate Microcapsules for Cell Therapy – A study of the structure-function relationships in native and structurally engineered alginates

    OpenAIRE

    Mørch, Yrr A.

    2008-01-01

    Alginate microcapsules have the potential as immune barriers for cell transplantation where the alginate gel protects the transplant from the host immune system. Microencapsulation can thus provide a way to overcome the need for immunosuppressive drugs. The successful use of alginates as immobilization material has, however, been hampered by their mechanical instability and high porosity. To overcome this problem, a polycation layer has traditionally been added to the alginate gels. However, ...

  5. Ca alginate as scaffold for iron oxide nanoparticles synthesis

    Directory of Open Access Journals (Sweden)

    P. V. Finotelli

    2008-12-01

    Full Text Available Recently, nanotechnology has developed to a stage that makes it possible to process magnetic nanoparticles for the site-specific delivery of drugs. To this end, it has been proposed as biomaterial for drug delivery system in which the drug release rates would be activated by a magnetic external stimuli. Alginate has been used extensively in the food, pharmaceutical and biomedical industries for their gel forming properties in the presence of multivalent cations. In this study, we produced iron oxide nanoparticles by coprecipitation of Fe(III and Fe(II. The nanoparticles were entrapped in Ca alginate beads before and after alginate gelation. XRD analysis showed that particles should be associated to magnetite or maghemite with crystal size of 9.5 and 4.3 nm, respectively. Studies using Mössbauer spectroscopy corroborate the superparamagnetic behavior. The combination of magnetic properties and the biocompatibility of alginate suggest that this biomaterial may be used as biomimetic system.

  6. Understanding Alginate Gel Development for Bioclogging and Biogeophysical Experiments

    Science.gov (United States)

    Brown, I.; Atekwana, E. A.; Abdel Aal, G. Z.; Atekwana, E. A.; Sarkisova, S.; Patrauchan, M.

    2012-12-01

    Bioremediation strategies to mitigate the transport of heavy metals and radionuclides in subsurface sediments have largely targeted to increase the mobility and/or solubility of these compounds by the stimulation of biogeochemical activity of the metal- and sulfate-reducing bacteria. The latter secrete and/or release out diverse biochemical molecule including, first of all, organic acids and biopolymers such as alginic acid, proteins and DNA. Alginate gel is one of the major components determining the structure of biofilm which causes clogging in porous media. Biopolymers composing biofilm having, at least, two main functions: to be a scaffold for a microbial biofilm, and to regulate the exchange of metabolites and ions between an environment and bacterial cells. Additionally, the accumulation of biopolymers and a matured biofilm within porous media was shown to contribute to a detectable biogeophysical signal, spectral induced polarization (SIP), in particular. Our objective is to understand the role of different biofilm components on the SIP response as the latter has been proposed as a non-invasive tool to monitor biofilm development and rate of clogging in the subsurface. Understanding the process of alginate gel development may aid in the understanding of the fate and transport of mineralized heavy metals and radionuclides in contaminated soils. Here we describe the reciprocal relationship between environmental chemistry and alginate gel development. Commercial (Sigma) alginic acid (AA) was used as a substratum for the preparation of a model gel. AA was solubilized by adjusting solutions with pH up to 4 with 0.1 NaOH. Both Ca(OH)2 or CaCl2 were used to initiate the gelation of alginate. pH, fluid conductivity, soluble Ca2+ concentration, and a yield of gelated alginate were monitored in both liquid and porous media after the interaction of calcium compounds with alginate. This study confirms the critical role of Ca2+ for alginate gelation, biofilm development

  7. Digestion of algin by Pseudomonas maltophilia and Pseudomonas putida.

    OpenAIRE

    von Riesen, V L

    1980-01-01

    Pseudomonas maltophilia and Pseudomonas putida were identified as alginolytic species. Two media used for demonstrating alginolytic activity are described. The applied aspects of the ability of these two species to digest algin are discussed.

  8. In situ growth of gold colloids within alginate films

    International Nuclear Information System (INIS)

    Gold-alginate bionanocomposite films were prepared by impregnation of alginate films with HAuCl4 followed by reduction with glucose. The mannuronate over guluronate ratio (M/G) of the polymer as well as the initial polymer concentration were shown to influence the film thickness, the amount of trapped Au3+ ions, and the volume fraction of Au(0) nanoparticles but not the size of these colloids (about 4 nm). The homogeneity of the gold colloid dispersion within the alginate gels was studied by transmission electron microscopy (TEM) and confirmed by simulation of the surface plasmon resonance (SPR) spectra using the Maxwell-Garnett model. The calculated spectra also provided fruitful information about the gold colloid/alginate interface. Overall, the whole process is controlled by the balance between the M/G ratio, defining the polymer affinity for Au(III) species, and the solution viscosity, controlling the diffusion phenomena.

  9. Optimalised Carbodiimide Chemistry for RGD-coupled Alginate

    OpenAIRE

    McDonagh, Birgitte Hjelmeland

    2012-01-01

    Alginate is a naturally ocurring polyanion of (1→4)linked β-d-mannuronic acid (M)and its C-5 epimer α-l guluronic acid (G). The polyanion, and particularly longstretches of guluronic acids, chelates and form hydrogels in the presence of divalentcations such as Ca2+ . Chelation occur at physiological conditions and the formed hy-drogels are biocompatible and stable. These properties nominates alginate hydrogelsas promising biomaterials in tissue engineering applicat...

  10. Ocular hypotensive efficacy and safety of once daily carteolol alginate

    OpenAIRE

    Demailly, P.; Allaire, C.; Trinquand, C.

    2001-01-01

    BACKGROUND/AIM—Carteolol is a β adrenoceptor antagonist used topically to reduce intraocular pressure, typically twice daily. In an effort to provide a once daily dosing regimen, carteolol was formulated with 1% alginic acid. The objective of this study was to evaluate the efficacy and safety of carteolol alginate solution in comparison with standard carteolol solution.
METHODS—This was a double masked, parallel group, multicentre study. Patients with ocular hypertension or open angle glaucom...

  11. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.;

    2001-01-01

    During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant com......During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic...

  12. Radiation-induced degradation of polysaccharide sodium alginate

    International Nuclear Information System (INIS)

    The radiation-induced degradation of sodium alginate by 60Co γ-rays was investigated in air at ambient temperature, and the change in their molecular weights was measured by multi-angle laser light scattering detector equipped with gel permeation chromatography (MALLS/GPC). The molecular weight of sodium alginate decreases with the increase of absorbed dose in the range of 0-60 kGy at the dose rate of 80 Gy/ min. The dispersion of molecular weight distribution of sodium alginate becomes narrow along with the absorbed dose. The weight-average molecular weight (Mw) changes from 321596.5 to 10024 when the absorbed dose increases from o kGy to 60 kGy. It is found that the degraded sodium alginate with molecular weight peak of 6000 is 83.22% of cumulative weight fraction. Anyway, the sodium alginate may have comprehensive application in the fields of agriculture, medicine and cosmetology as it can be absorbed well by biological tissue, if its weight-average molecular weight is below 10000. It is also found that new components will be contained in the products of sodium alginate degraded by irradiation. The further study dealing with the checking the biological safety and purification shall be performed. (authors)

  13. Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase

    OpenAIRE

    Lorena Segale; Lorella Giovannelli; Paolo Mannina; Franco Pattarino

    2016-01-01

    In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as a...

  14. Smart designing of new hybrid materials based on brushite-alginate and monetite-alginate microspheres: Bio-inspired for sequential nucleation and growth

    Energy Technology Data Exchange (ETDEWEB)

    Amer, Walid [MAScIR Foundation, INANOTECH, Rabat Design, Rue Mohamed El Jazouli, Madinat El Irfane 10100 Rabat (Morocco); Abdelouahdi, Karima [Centre National pour la Recherche Scientifique et Technique (CNRST), Division UATRS, Angle Allal Fassi/FAR, B.P. 8027, Hay Riad, 10000 Rabat (Morocco); Ramananarivo, Hugo Ronald; Fihri, Aziz; El Achaby, Mounir [MAScIR Foundation, INANOTECH, Rabat Design, Rue Mohamed El Jazouli, Madinat El Irfane 10100 Rabat (Morocco); Zahouily, Mohamed [Laboratoire de Matériaux, Catalyse et Valorisation des Ressources Naturelles, URAC 24, Faculté des Sciences et Techniques, Université Hassan II, Mohammedia B.P. 146, 20650 (Morocco); Barakat, Abdellatif [SUPAGRO-INRA-CIRAD-UMR IATE 1208, Ingenierie des Agropolymères et Technologies Emergentes, 2, Place Pierre Viala-Bât 31, 34060 Montpellier cedex 1 (France); Djessas, Kamal [CNRS-PROMES Tecnosud, F-66100 Perpignan (France); Clark, James [Green Chemistry, Centre of Excellence, University of York, York YO10 5DD (United Kingdom); Solhy, Abderrahim, E-mail: a.solhy@mascir.com [MAScIR Foundation, INANOTECH, Rabat Design, Rue Mohamed El Jazouli, Madinat El Irfane 10100 Rabat (Morocco)

    2014-02-01

    In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX). - Graphical abstract: A new class of hybrid materials based on brushite{sub a}lginate and monetite{sub a}lginate were prepared for the first time by adopting a soft and clean route. Thanks to their gelling and swelling properties, alginate porous polysaccharide microspheres behave as nanoreactors for nucleating, growing and hosting of the phosphate cements such as brushite or monetite. - Highlights: • New structured hybrid materials are prepared from biopolymer and phosphates. • Evidence for a new route for the synthesis of hybrid materials alginate-brushite and alginate-monetite via ionotropic gel of alginate. • The concentration of phosphate has a role crucial for selectivity to monetite or brushite.

  15. Alginate Polymerization and Modification Are Linked in Pseudomonas aeruginosa

    Science.gov (United States)

    Fata Moradali, M.; Donati, Ivan; Sims, Ian M.; Ghods, Shirin

    2015-01-01

    ABSTRACT The molecular mechanisms of alginate polymerization/modification/secretion by a proposed envelope-spanning multiprotein complex are unknown. Here, bacterial two-hybrid assays and pulldown experiments showed that the catalytic subunit Alg8 directly interacts with the proposed copolymerase Alg44 while embedded in the cytoplasmic membrane. Alg44 additionally interacts with the lipoprotein AlgK bridging the periplasmic space. Site-specific mutagenesis of Alg44 showed that protein-protein interactions and stability were independent of conserved amino acid residues R17 and R21, which are involved in c-di-GMP binding, the N-terminal PilZ domain, and the C-terminal 26 amino acids. Site-specific mutagenesis was employed to investigate the c-di-GMP-mediated activation of alginate polymerization by the PilZAlg44 domain and Alg8. Activation was found to be different from the proposed activation mechanism for cellulose synthesis. The interactive role of Alg8, Alg44, AlgG (epimerase), and AlgX (acetyltransferase) on alginate polymerization and modification was studied by using site-specific deletion mutants, inactive variants, and overproduction of subunits. The compositions, molecular masses, and material properties of resulting novel alginates were analyzed. The molecular mass was reduced by epimerization, while it was increased by acetylation. Interestingly, when overproduced, Alg44, AlgG, and the nonepimerizing variant AlgG(D324A) increased the degree of acetylation, while epimerization was enhanced by AlgX and its nonacetylating variant AlgX(S269A). Biofilm architecture analysis showed that acetyl groups promoted cell aggregation while nonacetylated polymannuronate alginate promoted stigmergy. Overall, this study sheds new light on the arrangement of the multiprotein complex involved in alginate production. Furthermore, the activation mechanism and the interplay between polymerization and modification of alginate were elucidated. PMID:25968647

  16. Studies on the PEO-PPO-PEO Block Copolymer Release from Alginate Hydrogel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Introduction Alginate hydrogel is one of the most widely used carriers for the immobilization of micro bial cells. If surfactants are encapsulated with alginate hydrogel, increasing temperature or concentration can make the encapsulated surfactants aggregate and form micelle.

  17. Decrease in dynamic viscosity and average molecular weight of alginate from Laminaria digitata during alkaline extraction

    OpenAIRE

    Vauchel, Peggy; Arhaliass, Abdellah; Legrand, Jack; Kaas, Raymond; Baron, Regis

    2008-01-01

    Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, i...

  18. Clinical evaluation of sodium alginate on oral mucositis associated with radiotherapy

    International Nuclear Information System (INIS)

    We evaluated the effect of sodium alginate on 39 patients with oral mucositis associated with radiotherapy. Sodium alginate was administered during radiotherapy to 17 patients with head and neck cancer. Compared with 22 patients without administration, sodium alginate reduced the pain and the erosion of oral mucosa significantly. Consequently the interval of radiotherapy was shortened. It is, therefore, expected that the effect of radiotherapy improves by the administration of sodium alginate. (author)

  19. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

  20. Alginate Nanoparticles as a Promising Adjuvant and Vaccine Delivery System

    Directory of Open Access Journals (Sweden)

    F Sarei

    2013-01-01

    Full Text Available During last decades, diphtheria has remained as a serious disease that still outbreaks and can occur worldwide. Recently, new vaccine delivery systems have been developed by using the biodegradable and biocompatible polymers such as alginate. Alginate nanoparticles as a carrier with adjuvant and prolong release properties that enhance the immunogenicity of vaccines. In this study diphtheria toxoid loaded nanoparticles were prepared by ionic gelation technique and characterized with respect to size, zeta potential, morphology, encapsulation efficiency, release profile, and immunogenicity. Appropriate parameters (calcium chloride and sodium alginate concentration, homogenization rate and homogenization time redounded to the formation of suitable nanoparticles with a mean diameter of 70±0.5 nm. The loading studies of the nanoparticles resulted in high loading capacities (>90% and subsequent release studies showed prolong profile. The stability and antigenicity of toxoid were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and ouchterlony test and proved that the encapsulation process did not affect the antigenic integrity and activity. Guinea pigs immunized with the diphtheria toxoid-loaded alginate nanoparticles showed highest humoral immune response than conventional vaccine. It is concluded that, with regard to the desirable properties of nanoparticles and high immunogenicity, alginate nanoparticles could be considered as a new promising vaccine delivery and adjuvant system.

  1. Use of antacids, alginates and proton pump inhibitors

    DEFF Research Database (Denmark)

    Lødrup, Anders; Reimer, Christine; Bytzer, Peter

    2014-01-01

    OBJECTIVE: Both over-the-counter medicine, such as antacids or alginates, and proton pump inhibitors (PPI) are used for treating acid-related disorders. We sought to describe what characterizes users of these different medicines, including long-term PPI users within the general population. METHOD......: A cross-sectional survey was conducted in an internet panel representative of the Danish adult population in 2012. Data queried included antacid/alginate and PPI use, reason for therapy, co-medication, and presence of upper gastrointestinal symptoms. Long-term PPI use was defined as using PPI ≥1.......6%; 6.2% were defined as long-term PPI users. Antacid/alginate users were younger, used less co-medication, had most often started on therapy because of reflux symptoms, and had less often ongoing symptoms. Risk of long-term PPI use appeared to be increased in male gender, by renewing PPI prescription...

  2. Fundamental Characteristics of Bioprint on Calcium Alginate Gel

    Science.gov (United States)

    Umezu, Shinjiro; Hatta, Tatsuru; Ohmori, Hitoshi

    2013-05-01

    The goal of this study is to fabricate precision three-dimensional (3D) biodevices those are micro fluidics and artificial organs utilizing digital fabrication. Digital fabrication is fabrication method utilizing inkjet technologies. Electrostatic inkjet is one of the inkjet technologies. The electrostatic inkjet method has following two merits; those are high resolution to print and ability to eject highly viscous liquid. These characteristics are suitable to print biomaterials precisely. We are now applying for bioprint. In this paper, the electrostatic inkjet method is applied for fabrication of 3D biodevices that has cave like blood vessel. When aqueous solution of sodium alginate is printed to aqueous solution of calcium chloride, calcium alginate is produced. 3D biodevices are fabricated in case that calcium alginate is piled.

  3. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.; Heydorn, Arne; Molin, Søren; Givskov, Michael Christian; Parsek, M.R.

    2001-01-01

    During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant com......During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic...... abiotic surface. Biofilms formed by an alginate- overproducing strain exhibit a highly structured architecture and are significantly more resistant to the antibiotic tobramycin than a biofilm formed by an isogenic nonmucoid strain. These results suggest that an important consequence of the conversion to...... mucoidy is an altered biofilm architecture that shows increasing resistance to antimicrobial treatments....

  4. Access to Chondrocyte Culture, with Alginate, In Iran

    Directory of Open Access Journals (Sweden)

    Ebrahim Esfandiary

    2008-01-01

    Full Text Available In this study, chondrocyte culture was established for the first time in Iran,and calcium alginate was used for longer culture of chondrocyte in vitro. Thestudy was programmed in order to be used for future human chondrocytetransplantation. The cartilage specimen obtained from 50 patients whounderwent total knee and hip operations in Isfahan University of MedicalSciences. Cartilage specimens were used for monolayer as well as suspensionculture in alginate beads. Approximately 12±1 millions cells were harvestedfrom the 3rd passage. The cells were round with large euchromatic nucleusand several nucleoli and small vacuoles. The cells derived from passages 1to 4, which were grown up then, in alginate beads, showed higher stainingwith alcian blue. The harvested cells in some patients were immediately andsuccessfully used for autologus transplantation. This later work will be reportedseparately.

  5. Alginate based polyurethanes: A review of recent advances and perspective.

    Science.gov (United States)

    Zia, Khalid Mahmood; Zia, Fatima; Zuber, Mohammad; Rehman, Saima; Ahmad, Mirza Nadeem

    2015-08-01

    The trend of using biopolymers in combination with synthetic polymers was increasing rapidly from last two or three decades. Polysaccharide based biopolymers especially starch, cellulose, chitin, chitosan, alginate, etc. found extensive applications for different industrial uses, as they are biocompatible, biodegradable, bio-renewable resources and chiefly environment friendly. Segment block copolymer character of polyurethanes that endows them a broad range of versatility in terms of tailoring their properties was employed in conjunction with various natural polymers resulted in modified biomaterials. Alginate is biodegradable, biocompatible, bioactive, less toxic and low cost anionic polysaccharide, as a part of structural component of bacteria and brown algae (sea weed) is quite abundant in nature. It is used in combination with polyurethanes to form elastomers, nano-composites, hydrogels, etc. that especially revolutionized the food and biomedical industries. The review summarized the development in alginate based polyurethanes with their potential applications. PMID:25964178

  6. The Use of Alginate in Lemon Extract Effervescent Powder Production

    Directory of Open Access Journals (Sweden)

    Murdinah

    2015-11-01

    Full Text Available Study on the use of alginate in lemon (Citrus medica var lemon extract effervescent powder production has conducted. The aims of the research are to determine the optimum concentration of alginate used in lemon extract effervescent powder to produced best product and acceptance consumen.The lemon extract effervescent powder formula consisted of lemon extract powder, sucrose, aspartame, salt and effervescent mix (citric acid-tartrat acid-sodium bicarbonat. The alginate used in this study was extracted from Sargassum filipendula sea weed. The concentration of alginate used in lemon effervescent powder production was varied from 1; 2; 3 and 4%. The parameters observed to see the quality of the product were moisture content, ash content, pH, viscosity and organoleptic value (flavor, taste, viscosity, effec effervescent, effect sparkle and acceptance. Analysis of dietary fiber, sugar content, vitamin C content, total titratable acids, TPC and E.Coli to the best product. The result showed that the higher the concentration of alginate used in lemon effervescent powder production, the higher viscousness and the lower the organoleptic value. The optimum concentration of alginate used in the lemon extract effervescent powder processing was 1%. The characteristic this product 7.60% moisture content, 0.86% insoluble dietary fiber , 7.92% soluble dietary fiber, 3.74% sugar content, 55,26 mg/100 g vitamin C, 134.15 mL 0.1 NaOH/100 mL total titratable acids, 20 cPs viscosity, <2.5x102 coloni/mL TPC and E.Coli negative.

  7. Use of 111In-labeled alginate to study the pH dependence of alginic acid anti-esophageal reflux barrier

    International Nuclear Information System (INIS)

    Mixtures of alginic acid and antacid, when given orally, react with gastric acid to form a viscous barrier (raft) which floats on the surface of the gastric contents. 111In was used to label magnesium alginate in order to study the effect of gastric acidity on the extent of formation of the raft. In vitro, acid concentrations less than 0.05 N diminished raft formation. In vivo, raft formation was significantly better in normal subjects who ingested dilute acid with the labeled alginate/antacid than in subjects who ingested the labeled alginate/antacid with plain water. Gastric emptying of the labeled alginate was also slowed by the presence of acidified gastric contents. These results suggest that the formation of an effective alginic acid antireflux barrier requires acidic gastric contents. (author)

  8. SYNTHESIS AND FLOCCULABILITY OF SODIUM ALGINATE GRAFTED WITH ACRYLAMIDE

    Institute of Scientific and Technical Information of China (English)

    Kaiqiang Xu; Xiongli Xu; Zhiji Ding; Meihua Zhou

    2006-01-01

    Graft copolymers of sodium alginate (SA) with acrylamide (AM) were synthesized using aceric ion initiated solution polymerization technique. The acrylamide conversions were studied by changing reaction conditions, such as temperature, molecular weight of sodium alginate and reaction time. The flocculation performance of the graft copolymer(SAG) was investigated in kaolin suspension and also in dyeing waste water. It was found that SAG is more efficient in flocculation behavior as compared to polyacrylamide and SA in kaolin suspension, and in removal capacities for CODCr and colority in dyeing wastewater.

  9. Ionically cross-linked alginate hydrogels as tissue engineering scaffolds

    Science.gov (United States)

    Kuo, Catherine Kyleen

    Generation of living tissues through tissue engineering can be achieved via incorporation of cells into synthetic scaffolds designed to facilitate new tissue formation. Necessary characteristics of a scaffold include biocompatibility, high porosity with controllable pore size and interconnectivity, moldability, chemical and mechanical stability, and structural homogeneity. Hydrogels often possess many of the necessary characteristics and thus are favorable candidates for scaffolding. Alginate hydrogels are commonly made by ionically crosslinking with calcium ions from CaCl2 or CaSO4. These hydrogels are favored for their mild gel formation, however the gelation rate is rapid and uncontrollable (fast-gelation), resulting in varying crosslinking density throughout the gel. In this work, structurally homogeneous calcium alginate hydrogels were formed via a slow-gelation system that utilizes uniform mixing of CaCO3 with sodium alginate solution, and the addition of slowly hydrolyzing D-gluconic acid lactone to slowly release calcium ions for crosslinking. Homogeneity and mechanical properties of these hydrogels were shown to be superior to those of fast-gelled hydrogels. Gelation rate was controlled through the incorporation of CaSO4, and by varying total calcium content, polymer concentration and gelation temperature. Control over mechanical properties and diffusivity was demonstrated in the homogeneous hydrogels by adjusting compositional variables. Consistent control over solute diffusivity through gel discs reflected the structural homogeneity of the gels. To overcome the instability of ionically crosslinked gels in tissue culture medium, a method was developed to control the hydrogel dimensions by adjusting the ionic concentration of the medium. Stability of the hydrogels in this controlled environment was characterized through swelling experiments and mechanical testing. To provide for scaffold degradation and thereby promote tissue growth, alginate lyase was

  10. Characterization of Sulfated Alginate Hybrid Gels for Tissue Engineering

    OpenAIRE

    Aaen, Ragnhild

    2015-01-01

    Tissue engineering is a field aiming to replace damaged tissue while reducing the great need of organ donors the world is facing today. Alginates are linear co-polymers consisting of the two monosaccharides β-D-mannuronic acid (M), and its 5-epimer α-L-guluronic acid (G). They can form hydrogels, and are candidates for use in tissue engineering scaffolds. Alginate is readily available at a low cost, and its hydrogels meet requirements of scaffolds such as mechanical strength and good biocomp...

  11. Bio-based barium alginate film: Preparation, flame retardancy and thermal degradation behavior.

    Science.gov (United States)

    Liu, Yun; Zhang, Chuan-Jie; Zhao, Jin-Chao; Guo, Yi; Zhu, Ping; Wang, De-Yi

    2016-03-30

    A bio-based barium alginate film was prepared via a facile ionic exchange and casting approach. Its flammability, thermal degradation and pyrolysis behaviors, thermal degradation mechanism were studied systemically by limiting oxygen index (LOI), vertical burning (UL-94), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) coupled with Fourier transform infrared analysis (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). It showed that barium alginate film had much higher LOI value (52.0%) than that of sodium alginate film (24.5%). Moreover, barium alginate film passed the UL-94 V-0 rating, while the sodium alginate film showed no classification. Importantly, peak of heat release rate (PHRR) of barium alginate film in MCC test was much lower than that of sodium alginate film, suggested that introduction of barium ion into alginate film significantly decreased release of combustible gases. TG-FTIR and Py-GC-MS results indicated that barium alginate produced much less flammable products than that of sodium alginate in whole thermal degradation procedure. Finally, a possible degradation mechanism of barium alginate had been proposed. PMID:26794953

  12. Effects of Composition of Iron-Cross-Linked Alginate Hydrogels for Cultivation of Human Dermal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Ikuko Machida-Sano

    2012-01-01

    Full Text Available We investigated the suitability of ferric-ion-cross-linked alginates (Fe-alginate with various proportions of L-guluronic acid (G and D-mannuronic acid (M residues as a culture substrate for human dermal fibroblasts. High-G and high-M Fe-alginate gels showed comparable efficacy in promoting initial cell adhesion and similar protein adsorption capacities, but superior cell proliferation was observed on high-G than on high-M Fe-alginate as culture time progressed. During immersion in culture medium, high-G Fe-alginate showed little change in gel properties in terms of swelling and polymer content, but the properties of high-M Fe-alginate gel were altered due to loss of ion cross-linking. However, the degree of cell proliferation on high-M Fe-alginate gel was improved after it had been stabilized by immersion in culture medium until no further changes occurred. These results suggest that the mode of cross-linkage between ferric ions and alginate differs depending on alginate composition and that the major factor giving rise to differences in cell growth on the two types of Fe-alginate films is gel stability during culture, rather than swelling of the original gel, polymer content, or protein adsorption ability. Our findings may be useful for extending the application of Fe-alginate to diverse biomedical fields.

  13. Modified calcium alginate as a highly efficient means for eliminating radioactive strontium

    International Nuclear Information System (INIS)

    Efficiency of various alginate samples in binding strontium depending on nature of original raw material, molecular mass of alginate, its salt form, guluronic acid content was studied do develop medicine for eliminating radioactive strontium from human digestive tract. Alginates of Laminaria japonica and mixtures of L. digitala and L. saccharina were studied. High-molecular alginates displayed low sorption efficiency of radioactive strontium. Fine results were obtained for alginates prepared out algae grafts. Modified calcium alginate tarned out to highly effective in removal of radioactive strontium. Calcium salt of low-molecular alginate enriched by guluronic acid turned out to be more efficient in strontium-85 sorption in rat gastrointestinal tract as compared to sodium salt. High efficiency was revealed in preventing radioactive strontium sorption in case of chronic irradiation

  14. Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

    OpenAIRE

    Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin; Hwang, Hyeon-Shik

    2016-01-01

    Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions wer...

  15. Evaluation of the effect of CaCl2 and alginate concentrations and hardening time on the characteristics of Lactobacillus acidophilus loaded alginate beads using response surface analysis

    Directory of Open Access Journals (Sweden)

    Farzaneh Lotfipour

    2012-06-01

    Full Text Available Purpose: This article describes preparation and characterization of beads of alginate containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Methods: Fourteen formulations using different alginate (ALG and CaCl2 concentrations as well as hardening times were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology, encapsulation efficiency and bacterial viabilities in acid (pH 1.8, 2 hours condition. Results: The results showed that spherical beads with narrow size distribution ranging from 1.32±0.04 to 1.70±0.07 mm were achieved with encapsulation efficiency higher than 98%. Surface response analysis revealed that alginate concentration was the important factor for the size, shape and encapsulation efficiency of prepared beads. Furthermore, survived bacteria after acid exposure in all prepared beads (63-83% were significantly higher than those of untreated cells (39% and enhanced by increasing alginate concentration. Surface response analysis revealed that the effect of all three factors of alginate and CaCl2 concentrations as well as hardening times were significant in acid viability, however alginate concentration played the most important role according to its regression coefficient. Conclusion: Among alginate and CaCl2 concentrations as well as hardening times, alginate concentration was the most variable in the characteristics of Alginate beads.

  16. Smart designing of new hybrid materials based on brushite-alginate and monetite-alginate microspheres: Bio-inspired for sequential nucleation and growth

    International Nuclear Information System (INIS)

    In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX). - Graphical abstract: A new class of hybrid materials based on brushitealginate and monetitealginate were prepared for the first time by adopting a soft and clean route. Thanks to their gelling and swelling properties, alginate porous polysaccharide microspheres behave as nanoreactors for nucleating, growing and hosting of the phosphate cements such as brushite or monetite. - Highlights: • New structured hybrid materials are prepared from biopolymer and phosphates. • Evidence for a new route for the synthesis of hybrid materials alginate-brushite and alginate-monetite via ionotropic gel of alginate. • The concentration of phosphate has a role crucial for selectivity to monetite or brushite

  17. In vitro evaluation of alginate/halloysite nanotube composite scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Mingxian [Department of Materials Science and Engineering, Jinan University, Guangzhou 510632 (China); Dai, Libing [Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital Medical College, Jinan University, Guangzhou 510220 (China); Shi, Huizhe; Xiong, Sheng [Institute of Biomedicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Department of Materials Science and Engineering, Jinan University, Guangzhou 510632 (China)

    2015-04-01

    In this study, a series of alginate/halloysite nanotube (HNTs) composite scaffolds were prepared by solution-mixing and freeze-drying method. HNTs are incorporated into alginate to improve both the mechanical and cell-attachment properties of the scaffolds. The interfacial interactions between alginate and HNTs were confirmed by the atomic force microscope (AFM), transmission electron microscope (TEM) and FTIR spectroscopy. The mechanical, morphological, and physico-chemical properties of the composite scaffolds were investigated. The composite scaffolds exhibit significant enhancement in compressive strength and compressive modulus compared with pure alginate scaffold both in dry and wet states. A well-interconnected porous structure with size in the range of 100–200 μm and over 96% porosity is found in the composite scaffolds. X-ray diffraction (XRD) result shows that HNTs are uniformly dispersed and partly oriented in the composite scaffolds. The incorporation of HNTs leads to increase in the scaffold density and decrease in the water swelling ratio of alginate. HNTs improve the stability of alginate scaffolds against enzymatic degradation in PBS solution. Thermogravimetrica analysis (TGA) shows that HNTs can improve the thermal stability of the alginate. The mouse fibroblast cells display better attachment to the alginate/HNT composite than those to the pure alginate, suggesting the good cytocompatibility of the composite scaffolds. Alginate/HNT composite scaffolds exhibit great potential for applications in tissue engineering. - Highlights: • We fabricated HNTs reinforced alginate composite scaffolds for biomedical applications. • The hydrogen bond interactions between HNTs and alginate are confirmed. • HNTs can significantly enhance the mechanical properties of alginate scaffold. • The scaffolds exhibit a highly porous structure with interconnected pores. • HNTs can improve the cell attachment and proliferation on alginate.

  18. Microencapsulation of eugenol by gelatin-sodium alginate complex coacervation

    OpenAIRE

    Ujwala Shinde; Mangal Nagarsenker

    2011-01-01

    Present study describes microencapsulation of eugenol using gelatin-sodium alginate complex coacervation. The effects of core to coat ratio and drying method on properties of the eugenol microcapsules were investigated. The eugenol microcapsules were evaluated for surface characteristics, micromeritic properties, oil loading and encapsulation efficiency. Eugenol microcapsules possessed good flow properties, thus improved handling. The scanning electron photomicrographs showed globular surface...

  19. Structural Basis for Alginate Secretion Across the Bacterial Outer Membrane

    Energy Technology Data Exchange (ETDEWEB)

    J Whitney; I Hay; C Li; P Eckford; H Robinson; M Amaya; L Wood; D Ohman; C Bear; et al.

    2011-12-31

    Pseudomonas aeruginosa is the predominant pathogen associated with chronic lung infection among cystic fibrosis patients. During colonization of the lung, P. aeruginosa converts to a mucoid phenotype characterized by the overproduction of the exopolysaccharide alginate. Secretion of newly synthesized alginate across the outer membrane is believed to occur through the outer membrane protein AlgE. Here we report the 2.3 {angstrom} crystal structure of AlgE, which reveals a monomeric 18-stranded {beta}-barrel characterized by a highly electropositive pore constriction formed by an arginine-rich conduit that likely acts as a selectivity filter for the negatively charged alginate polymer. Interestingly, the pore constriction is occluded on either side by extracellular loop L2 and an unusually long periplasmic loop, T8. In halide efflux assays, deletion of loop T8 ({Delta}T8-AlgE) resulted in a threefold increase in anion flux compared to the wild-type or {Delta}L2-AlgE supporting the idea that AlgE forms a transport pathway through the membrane and suggesting that transport is regulated by T8. This model is further supported by in vivo experiments showing that complementation of an algE deletion mutant with {Delta}T8-AlgE impairs alginate production. Taken together, these studies support a mechanism for exopolysaccharide export across the outer membrane that is distinct from the Wza-mediated translocation observed in canonical capsular polysaccharide export systems.

  20. Structural basis for alginate secretion across the bacterial outer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, J.C.; Robinson, H.; Hay, I. D.; Li, C.; Eckford, P. D. W.; Amaya, M. F.; Wood, L. F.; Ohman, D. E.; Bear, C. E.; Rehm, B. H.; Howell, P. L.

    2011-08-09

    Pseudomonas aeruginosa is the predominant pathogen associated with chronic lung infection among cystic fibrosis patients. During colonization of the lung, P. aeruginosa converts to a mucoid phenotype characterized by the overproduction of the exopolysaccharide alginate. Secretion of newly synthesized alginate across the outer membrane is believed to occur through the outer membrane protein AlgE. Here we report the 2.3 {angstrom} crystal structure of AlgE, which reveals a monomeric 18-stranded {beta}-barrel characterized by a highly electropositive pore constriction formed by an arginine-rich conduit that likely acts as a selectivity filter for the negatively charged alginate polymer. Interestingly, the pore constriction is occluded on either side by extracellular loop L2 and an unusually long periplasmic loop, T8. In halide efflux assays, deletion of loop T8 ({Delta}T8-AlgE) resulted in a threefold increase in anion flux compared to the wild-type or {Delta}L2-AlgE supporting the idea that AlgE forms a transport pathway through the membrane and suggesting that transport is regulated by T8. This model is further supported by in vivo experiments showing that complementation of an algE deletion mutant with {Delta}T8-AlgE impairs alginate production. Taken together, these studies support a mechanism for exopolysaccharide export across the outer membrane that is distinct from the Wza-mediated translocation observed in canonical capsular polysaccharide export systems.

  1. Reinforcement of porous alginate scaffolds by incorporating electrospun fibres.

    Science.gov (United States)

    Sakai, Shinji; Takagi, Yousuke; Yamada, Yusuke; Yamaguchi, Tetsu; Kawakami, Koei

    2008-09-01

    The mechanical properties of scaffolds play a vital role in transmitting input mechanical signals to the cells within them. We aimed to modify mechanical properties of porous scaffolds by incorporating electrospun fibres into their frameworks. Porous constructs containing electrospun silicate fibres were prepared from Na-alginate aqueous solutions suspending the silicate fibres with (ASF) or without amino groups (NASF) via an all-aqueous method based on a freeze-drying technique. The repulsion forces of constructs containing ASF towards compression increased as the fibre content increased. In contrast, constructs containing NASF showed no such increases in repulsion forces. Cells seeded onto constructs containing ASF exhibited suppressed growth, similar to cells seeded onto alginate scaffolds without fibres. In contrast, cells seeded onto scaffolds containing NASF showed about two-fold faster growth than cells seeded onto scaffolds containing ASF. The differences in the mechanical properties and cell growth profiles between the scaffolds containing ASF and NASF can be explained by the formation and non-formation of electrostatic bonds between the fibres and alginate, respectively. The results obtained in the present study demonstrate the feasibility of incorporating electrospun fibres for reinforcement of alginate scaffolds and enhancement of cell growth. PMID:18689918

  2. Reinforcement of porous alginate scaffolds by incorporating electrospun fibres

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Shinji; Takagi, Yousuke; Yamada, Yusuke; Yamaguchi, Tetsu; Kawakami, Koei [Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2008-09-01

    The mechanical properties of scaffolds play a vital role in transmitting input mechanical signals to the cells within them. We aimed to modify mechanical properties of porous scaffolds by incorporating electrospun fibres into their frameworks. Porous constructs containing electrospun silicate fibres were prepared from Na-alginate aqueous solutions suspending the silicate fibres with (ASF) or without amino groups (NASF) via an all-aqueous method based on a freeze-drying technique. The repulsion forces of constructs containing ASF towards compression increased as the fibre content increased. In contrast, constructs containing NASF showed no such increases in repulsion forces. Cells seeded onto constructs containing ASF exhibited suppressed growth, similar to cells seeded onto alginate scaffolds without fibres. In contrast, cells seeded onto scaffolds containing NASF showed about two-fold faster growth than cells seeded onto scaffolds containing ASF. The differences in the mechanical properties and cell growth profiles between the scaffolds containing ASF and NASF can be explained by the formation and non-formation of electrostatic bonds between the fibres and alginate, respectively. The results obtained in the present study demonstrate the feasibility of incorporating electrospun fibres for reinforcement of alginate scaffolds and enhancement of cell growth.

  3. Magnetic alginate microparticles for purification of .alpha.-amylases

    Czech Academy of Sciences Publication Activity Database

    Šafaříková, Miroslava; Roy, I.; Gupta, M. N.; Šafařík, Ivo

    2003-01-01

    Roč. 105, - (2003), s. 255-260. ISSN 0168-1656 R&D Projects: GA MŠk OC 523.80; GA AV ČR IBS6087204 Institutional research plan: CEZ:AV0Z6087904 Keywords : alginate * ferrofluid * amalyses Subject RIV: CE - Biochemistry Impact factor: 2.543, year: 2003

  4. Inhibition of tobramycin diffusion by binding to alginate

    International Nuclear Information System (INIS)

    [3H]tobramycin bound to sodium alginate and to exopolysaccharide prepared from two mucoid strains of Pseudomonas aeruginosa. Binding to sodium alginate was similar to binding to exopolysaccharide, both in the dependence on tobramycin concentration and in the maximum binding observed at saturation. Incorporation of sodium alginate into agar plates reduced the zone sizes of growth inhibition caused by tobramycin. The reductions in zone sizes were quantitatively accounted for by the binding of tobramycin to sodium alginate during diffusion of the antibiotic away from the well in which it had been placed at the start of the experiment. However, the binding of tobramycin to the exopolysaccharide of P. aeruginosa, and the resulting inhibition of diffusion of the antibiotic, did not significantly increase the penetration time of a spherical microcolony with a radius of 125 micron, such as might be found in the respiratory tract of a patient with cystic fibrosis (from a 90% penetration time of 12 s in the absence of exopolysaccharide to one of 35 s with an exopolysaccharide concentration of 1.0% [wt/vol])

  5. Chitosan and alginate scaffolds for bone tissue regeneration.

    Science.gov (United States)

    Olmez, S S; Korkusuz, P; Bilgili, H; Senel, S

    2007-06-01

    Polymeric scaffold for tissue regeneration was developed for veterinary applications. Oxytetracycline hydrochloride (OTC), which is a widely used antibiotic in veterinary medicine was chosen as the model compound. Gel formulations using chitosan and alginate were prepared in distilled water or in 1% (v/v) acetic acid solution. Sponges were also prepared by a freeze-drying process. Tripolyphosphate was used for cross-linking. Viscosity was decreased in the presence of OTC in chitosan gels whereas no difference was found with alginate gels. All gels showed pseudoplastic behaviour. Water absorption capacity was highest with chitosan/alginate sponges. The solvent used for preparation of the chitosan gels was found to affect the release of OTC. The release of OTC from the sponges was increased by cross-linking. Chitosan/alginate sponges showed the slowest and lowest drug release among the developed sponge formulations in this study. The formulations were found to be biocompatible, inducing no adverse reaction in vivo on surgically formed bone defects of radius of rabbits. The level of organization of the remodelled new bone in the treatment groups was better than that of control. Incorporation of OTC into formulations did not show any considerable enhancing effect. PMID:17663189

  6. Kefiran-alginate gel microspheres for oral delivery of ciprofloxacin.

    Science.gov (United States)

    Blandón, Lina M; Islan, German A; Castro, Guillermo R; Noseda, Miguel D; Thomaz-Soccol, Vanete; Soccol, Carlos R

    2016-09-01

    Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms. PMID:27289312

  7. Alginate Hydrogels Coated with Chitosan for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Maria Cristina Straccia

    2015-05-01

    Full Text Available In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl, with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.

  8. Insulin-loaded alginic acid nanoparticles for sublingual delivery.

    Science.gov (United States)

    Patil, Nilam H; Devarajan, Padma V

    2016-01-01

    Alginic acid nanoparticles (NPs) containing insulin, with nicotinamide as permeation enhancer were developed for sublingual delivery. The lower concentration of proteolytic enzymes, lower thickness and enhanced retention due to bioadhesive property, were relied on for enhanced insulin absorption. Insulin-loaded NPs were prepared by mild and aqueous based nanoprecipitation process. NPs were negatively charged and had a mean size of ∼200 nm with low dispersity index. Insulin loading capacities of >95% suggested a high association of insulin with alginic acid. Fourier Transform Infra-Red Spectroscopy (FTIR) spectra and DSC (Differential Scanning Calorimetry) thermogram of insulin-loaded NPs revealed the association of insulin with alginic acid. Circular dichroism (CD) spectra confirmed conformational stability, while HPLC analysis confirmed chemical stability of insulin in the NPs. Sublingually delivered NPs with nicotinamide exhibited high pharmacological availability (>100%) and bioavailability (>80%) at a dose of 5 IU/kg. The high absolute pharmacological availability of 20.2% and bioavailability of 24.1% in comparison with subcutaneous injection at 1 IU/kg, in the streptozotocin-induced diabetic rat model, suggest the insulin-loaded alginic acid NPs as a promising sublingual delivery system of insulin. PMID:24901208

  9. Deterioration of polyamino acid-coated alginate microcapsules in vivo.

    Science.gov (United States)

    van Raamsdonk, J M; Cornelius, R M; Brash, J L; Chang, P L

    2002-01-01

    The implantation of immuno-isolated recombinant cell lines secreting a therapeutic protein in alginate microcapsules presents an alternative approach to gene therapy. Its clinical efficacy has recently been demonstrated in treating several genetic diseases in murine models. However, its application to humans will depend on the long-term structural stability of the microcapsules. Based on previous implantations in canines, it appears that survival of alginate-poly-L-lysine-alginate microcapsules in such large animals is short-lived. This article reports on the biological factors that may have contributed to the degradation of these microcapsules after implantation in dogs. Alginate microcapsules coated with poly-L-lysine or poly-L-arginine were implanted in subcutaneous or intraperitoneal sites. The retrieved microcapsules showed a loss of mechanical stability, as measured by resistance to osmotic stress. The polyamino acid coats were rendered fragile and easily lost, particularly when poly-L-lysine was used for coating and the intraperitoneal site was used for implantation. Various plasma proteins were associated with the retrieved microcapsules and identified with western blotting to include Factor XI, Factor XII, prekallikrein, HMWK, fibrinogen, plasminogen, ATIII, transferrin, alpha-1-antitrypsin, fibronectin, IgG, alpha-2-macroglobulin, vitronectin, prothrombin, apolipoprotein A1, and particularly albumin, a major Ca-transporting plasma protein. Complement proteins (C3, Factor B, Factor H, Factor I) and C3 activation fragments were detected. Release of the amino acids from the microcapsule polyamino acid coats was observed after incubation with plasma. indicating the occurrence of proteolytic degradation. Hence, the loss of long-term stability of the polyamino acid-coated alginate microcapsules is associated with activation of the complement system, degradation of the polyamino acid coating, and destabilization of the alginate core matrix, probably through loss

  10. Covalent layer-by-layer assembly of hyperbranched polymers on alginate microcapsulesto impart stability and permselectivity.

    Science.gov (United States)

    Gattás-Asfura, Km; Valdes, M; Celik, E; Stabler, Cl

    2014-12-14

    The microencapsulation of cells has shown promise as a therapeutic vehicle for the treatment of a wide variety of diseases. While alginate microcapsules provide an ideal cell encapsulation material, polycations coatings are commonly employed to enhance stability and impart permselectivity. In this study, functionalized hyperbranched alginate and dendrimer polymers were used to generate discreet nanoscale coatings onto alginate microbeads via covalent layer-by-layer assembly. The bioorthogonal Staudinger ligation scheme was used to chemoselectively crosslink azide functionalized hyperbranched alginate (alginate-hN3) to methyl-2-diphenylphosphino-terephthalate (MDT) linked PAMAM dendrimer (PAMAM-MDT). Covalent layer-by-layer deposition of PAMAM-MDT/alginate-hN3 coatings onto alginate microbeads resulted in highly stable coatings, even after the inner alginate gel was liquefied to form microcapsules. The permselectivity of the coated microcapsules could be manipulated via the charge density of the PAMAM, the number of layers deposited, and the length of the functional arms. The cytocompatibility of the resulting PAMAM-MDT/alginate-hN3 coating was evaluated using a beta cell line, with no significant detrimental response observed. The biocompatibility of the coatings in vivo was also found comparable to uncoated alginate beads. The remarkable stability and versatile nature of these coatings provides an appealing option for bioencapsulation and the release of therapeutic agents. PMID:25478165

  11. Evaluation of fibroblasts adhesion and proliferation on alginate-gelatin crosslinked hydrogel.

    Directory of Open Access Journals (Sweden)

    Bapi Sarker

    Full Text Available Due to the relatively poor cell-material interaction of alginate hydrogel, alginate-gelatin crosslinked (ADA-GEL hydrogel was synthesized through covalent crosslinking of alginate di-aldehyde (ADA with gelatin that supported cell attachment, spreading and proliferation. This study highlights the evaluation of the physico-chemical properties of synthesized ADA-GEL hydrogels of different compositions compared to alginate in the form of films. Moreover, in vitro cell-material interaction on ADA-GEL hydrogels of different compositions compared to alginate was investigated by using normal human dermal fibroblasts. Viability, attachment, spreading and proliferation of fibroblasts were significantly increased on ADA-GEL hydrogels compared to alginate. Moreover, in vitro cytocompatibility of ADA-GEL hydrogels was found to be increased with increasing gelatin content. These findings indicate that ADA-GEL hydrogel is a promising material for the biomedical applications in tissue-engineering and regeneration.

  12. Improved Water Barrier Properties of Calcium Alginate Capsules Modified by Silicone Oil

    OpenAIRE

    Brian G. Zukas; Nivedita R. Gupta

    2016-01-01

    Calcium alginate films generally offer poor diffusion resistance to water. In this study, we present a technique for encapsulating aqueous drops in a modified calcium alginate membrane made from an emulsion of silicone oil and aqueous alginate solution and explore its effect on the loss of water from the capsule cores. The capsule membrane storage modulus increases as the initial concentration of oil in the emulsion is increased. The water barrier properties of the fabricated capsules were de...

  13. Studying the Enrichment of Ice Cream with Alginate Nanoparticles Including Fe and Zn Salts

    OpenAIRE

    Armoon Sharifi; Leila Golestan; Mazyar Sharifzadeh Baei

    2013-01-01

    The aim of this research was developing alginate nanoparticles as a carrier for food enrichment. In this research, Fe/Zn-loaded alginate nanoparticles were prepared and characterized as point size, morphology, FTIR, loading efficacy (LE), and release properties and used in ice cream structure. After this stage, absorption of the salts was measured and sensory and rheological evaluations were taken for samples. Results showed that alginate nanoparticles have average size between 90 and 135 nm....

  14. Microencapsulation of bull spermatozoa: Its viability in alginate-egg yolk media

    Directory of Open Access Journals (Sweden)

    Kusumaningrum DA

    2015-03-01

    Full Text Available Microencapsulation of spermatozoa is a process to entrap a number of spermatozoa in microcapsule. Alginate, as a natural polymer polysaccharide is commonly used in cell microencapsulation. Tris Yolk Citrate buffer is a good buffer for spermatozoa dilution, therefore this experiment aimed to determine optimal concentration of alginate and egg yolk to sperm quality in bull spermatozoa microencapsulation. Concentration of egg yolk and alginate in media of encapsulation were determined in applications of sperm microencapsulation. Four bulls were used as semen source and only semen with good quality were used in this study. Poolled semen was diluted using the medium to get final concentration 100 x 106 cell/ ml. The first study was conducted to determine the effect of concentration of alginate (0, 1, and 1.5% on viability of spermatozoa. The second study to determine the effect of alginate concentration, egg yolk and its interaction was done by comparing two levels of alginate (1 and 1.5% with four levels of egg yolk (5, 10, 15 and 20%. Viability of spermatozoa, motility (M, live spermatozoa (L and Intact Apical Ridge (IAR were observed at 0, 1, 2 and 3 h incubation at room temperature. Results indicated that alginate concentration increased the osmolality and viscosity but did not affect pH of the medium. The osmolality and viscosity of medium were 275, 325, 425 and 1.12, 26.62, 47.98 for concentration of alginate 0, 1 and 1.5% respectively. Percentage of motility is significantly lower (P<0.05 in alginate medium than those of control, and 1.5% alginate could produce more uniform beads. Concentration of alginate, egg yolk and its interaction did not significantly affect viability of sperm. It is concluded that the combination of 1.5% alginate with 5, 10, 15 or 20% egg yolk can be used as media for sperm encapsulation.

  15. Microencapsulation of bull spermatozoa: Its viability in alginate-egg yolk media

    OpenAIRE

    2015-01-01

    Microencapsulation of spermatozoa is a process to entrap a number of spermatozoa in microcapsule. Alginate, as a natural polymer polysaccharide is commonly used in cell microencapsulation. Tris Yolk Citrate buffer is a good buffer for spermatozoa dilution, therefore this experiment aimed to determine optimal concentration of alginate and egg yolk to sperm quality in bull spermatozoa microencapsulation. Concentration of egg yolk and alginate in media of encapsulation were determined in applica...

  16. Copper Alginate-Cotton Cellulose (CACC) Fibers with Excellent Antibacterial Properties

    OpenAIRE

    Navin Chand, Ph.D.; Sunil Kumar Bajpai, Ph.D.; Mary Grace, M.Sc.

    2009-01-01

    The present work describes synthesis of copper alginate-cotton cellulose (CACC) composite fibers and detailed investigation of antimicrobial action against the model bacteria E.coli. The CACC fibers were prepared by immersing cotton fibers in aqueous solution of sodium alginate, followed by ionic crosslinking of alginate chains within the cotton cellulose fibers with Cu(II) ions to yield CACC composite fibers. The resulting CACC fibers were investigated for their biocidal action against E.col...

  17. Kinetics of release of methylene blue immobilized in calcium alginate microparticles

    OpenAIRE

    Inal Bakhytkyzy; R. Ussenkyzy; D. Rahimbaeva

    2013-01-01

    The swelling kinetics of microparticles obtained with different concentrations of calcium chloride was studied to learn the ability of sodium alginate to gelation. To increase the effect of prolongation it is necessary to obtain microparticles with sustained release of drugs. For this purpose the drying kinetics of alginate microparticles was investigated. Also the kinetics of release of methylene blue immobilized in calcium alginate microparticles was studied. It was found that the release o...

  18. New insights into the biosynthesis of alginate in Pseudomonas fluorescens: from precursor synthesis to multiprotein factories

    OpenAIRE

    Maleki, Susan

    2015-01-01

    Alginate is a biopolymer that has numerous industrial and medical applications due to its favorable material properties, which is greatly affected by the polymer chain length and monomer composition. Currently, all commercially available alginates are obtained from brown algae; however, the polymer is also produced by bacteria belonging to the two genera Pseudomonas and Azotobacter. Genetic engineering of bacteria opens up new possibilities for production of alginates with more...

  19. Surface characteristics determining the cell compatibility of ionically cross-linked alginate gels

    International Nuclear Information System (INIS)

    In this study we investigated differences in the characteristics determining the suitability of five types of ion (Fe3+, Al3+, Ca2+, Ba2+ and Sr2+)-cross-linked alginate films as culture substrates for cells. Human dermal fibroblasts were cultured on each alginate film to examine the cell affinity of the alginates. Since cell behavior on the surface of a material is dependent on the proteins adsorbed to it, we investigated the protein adsorption ability and surface features (wettability, morphology and charge) related to the protein adsorption abilities of alginate films. We observed that ferric, aluminum and barium ion-cross-linked alginate films supported better cell growth and adsorbed higher amounts of serum proteins than other types. Surface wettability analysis demonstrated that ferric and aluminum ion-cross-linked alginates had moderate hydrophilic surfaces, while other types showed highly hydrophilic surfaces. The roughness was exhibited only on barium ion-cross-linked alginate surface. Surface charge measurements revealed that alginate films had negatively charged surfaces, and showed little difference among the five types of gel. These results indicate that the critical factors of ionically cross-linked alginate films determining the protein adsorption ability required for their cell compatibility may be surface wettability and morphology. (paper)

  20. Fabrication of freestanding alginate microfibers and microstructures for tissue engineering applications

    International Nuclear Information System (INIS)

    Natural biopolymers such as alginate have become important materials for a variety of biotechnology applications including drug delivery, cell encapsulation and tissue engineering. This expanding use has spurred the development of new approaches to engineer these materials at the nano- and microscales to better control cell interactions. Here we describe a method to fabricate freestanding alginate-based microfibers and microstructures with tunable geometries down to approximately 3 µm. To do this, a polydimethylsiloxane stamp is used to micromold alginate or alginate-fibrin blends onto a sacrificial layer of thermally-sensitive poly(N-isopropylacrylamide) (PIPAAm). A warm calcium chloride solution is then used to crosslink the alginate and, upon cooling below the lower critical solution temperature (∼32 °C), the PIPAAm layer dissolves and releases the alginate or alginate-fibrin as freestanding microfibers and microstructures. Proof-of-concept experiments demonstrate that C2C12 myoblasts seeded onto the alginate-fibrin microfibers polarize along the fiber length forming interconnected cell strands. Thus, we have developed the ability to engineer alginate-based microstructured materials that can selectively bind cells and direct cellular assembly. (paper)

  1. Pseudomonas aeruginosa AlgG is a polymer level alginate C5-mannuronan epimerase.

    OpenAIRE

    Franklin, M J; Chitnis, C E; Gacesa, P; Sonesson, A; White, D. C.; Ohman, D E

    1994-01-01

    Alginate is a viscous extracellular polymer produced by mucoid strains of Pseudomonas aeruginosa that cause chronic pulmonary infections in patients with cystic fibrosis. Alginate is polymerized from GDP-mannuronate to a linear polymer of beta-1-4-linked residues of D-mannuronate and its C5-epimer, L-guluronate. We previously identified a gene called algG in the alginate biosynthetic operon that is required for incorporation of L-guluronate residues into alginate. In this study, we tested the...

  2. Biocomposite cellulose-alginate films: promising packaging materials.

    Science.gov (United States)

    Sirviö, Juho Antti; Kolehmainen, Aleksi; Liimatainen, Henrikki; Niinimäki, Jouko; Hormi, Osmo E O

    2014-05-15

    Biocomposite films based on cellulose and alginate were produced using unmodified birch pulp, microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and birch pulp derivate, nanofibrillated anionic dicarboxylic acid cellulose (DCC), having widths of fibres ranging from 19.0 μm to 25 nm as cellulose fibre materials. Ionically cross-linked biocomposites were produced using Ca(2+) cross-linking. Addition of micro- and nanocelluloses as a reinforcement increased the mechanical properties of the alginate films remarkably, e.g. addition of 15% of NFC increased a tensile strength of the film from 70.02 to 97.97 MPa. After ionic cross-linking, the tensile strength of the film containing 10% of DCC was increased from 69.63 to 125.31 MPa. The biocomposite films showed excellent grease barrier properties and reduced water vapour permeability (WVP) after the addition of cellulose fibres, except when unmodified birch pulp was used. PMID:24423542

  3. Photonic monitoring of chitosan nanostructured alginate microcapsules for drug release

    Science.gov (United States)

    Khajuria, Deepak Kumar; Konnur, Manish C.; Vasireddi, Ramakrishna; Roy Mahapatra, D.

    2015-02-01

    By using a novel microfluidic set-up for drug screening applications, this study examines delivery of a novel risedronate based drug formulation for treatment of osteoporosis that was developed to overcome the usual shortcomings of risedronate, such as its low bioavailability and adverse gastric effects. Risedronate nanoparticles were prepared using muco-adhesive polymers such as chitosan as matrix for improving the intestinal cellular absorption of risedronate and also using a gastric-resistant polymer such as sodium alginate for reducing the gastric inflammation of risedronate. The in-vitro characteristics of the alginate encapsulated chitosan nanoparticles are investigated, including their stability, muco-adhesiveness, and Caco-2 cell permeability. Fluorescent markers are tagged with the polymers and their morphology within the microcapsules is imaged at various stages of drug release.

  4. Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

    Directory of Open Access Journals (Sweden)

    Enas N. Danial

    2015-04-01

    Full Text Available This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease was more stable in retention than that of the free enzyme during the storage in solution, although the activity of the immobilized enzyme was lower in comparison with the free enzyme. A stable immobilized system and long storage life are convenient for applications that would not be feasible with a soluble enzyme system. These results highlighted the technical and biochemical benefits of immobilized urease over the free enzyme.

  5. Isolation of Protoplasts from Undaria pinnatifida by Alginate Lyase Digestion

    Institute of Scientific and Technical Information of China (English)

    HU Xiaoke; JIANG Xiaolu; GUAN Huashi

    2003-01-01

    The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation is enzymatic digestion at 28 ℃ for 2 h using alginate lyase at the concentration of 213.36 U (8 mL) every 0.5 g fresh thalline with NaCl 50 and at the shaking speed of 150 r min-1 during digestion. The protoplast yield can reach 2.62 + 0.09 million per 0.5 g fresh leave under the optimum condition. The enzyme activity is inhibited by Ca2+ and slightly enhanced by Fe2+ and Mn2+ at concentrations of 0.05, 0.08 and 0.10 molL-1.

  6. Isolation of protoplasts from undaria pinnatifida by alginate lyase digestion

    Science.gov (United States)

    Xiaoke, Hu; Xiaolu, Jiang; Huashi, Guan

    2003-04-01

    The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation is enzymatic digestion at 28°C for 2h using alginate lyase at the concentration of 213.36 U (8 mL) every 0.5g fresh thalline with NaCl 50 and at the shaking speed of 150 r min-1 during digestion. The protoplast yield can reach 2.62±0.09 million per 0.5 g fresh leave under the optimum condition. The enzyme activity is inhibited by Ca2+ and slightly enhanced by Fe2+ and Mn2+ at concentrations of 0.05, 0.08 and 0.10 mol L-1.

  7. Diffusivity of Cu2+ in calcium alginate gel beads.

    Science.gov (United States)

    Jang, L K

    1994-01-20

    The diffusivity of Cu(2+) in calcium alginate beads calculated by the shrinking core model (SCM) was reevaluated in this work. The results obtained in this work were significantly different than those by the original authors. There were excellent agreements between the results obtained by the SCM in this work and those by the more rigorous linear absorption model (LAM) by the original authors. PMID:18615613

  8. Encapsulation of volatiles by homogenized partially-cross linked alginates.

    Science.gov (United States)

    Inguva, Pavan K; Ooi, Shing Ming; Desai, Parind M; Heng, Paul W S

    2015-12-30

    Cross-linked calcium alginate gels are too viscous to be efficaciously incorporated into spray dried formulations. Thus, viscosity reduction is essential to ensure the processability of calcium alginate gels to be sprayed. Viscosity reduction by high pressure homogenization can open new formulation possibilities. Presently, testing of microcapsule integrity is also limited because either single particle tests neglect collective particle behaviours in bulk or bulk testing methods are often associated with single compressions which may not fully characterize individual particle strengths. The aim of this study was sub-divided into three objectives. First objective was to evaluate the impact of high pressure homogenization on gel viscosity. Second objective was to explore the use of the homogenized gels with modified starch for microencapsulation by spray drying. The final objective was to develop a stamping system as microcapsule strength tester that can assess microcapsules in bulk and evaluate the impact of multiple compressions. Collectively, this study would lead towards developing a pressure-activated patch of microcapsules with encapsulated volatiles and the method to assess the patch efficacy. The alginate gels largely experienced an exponential decay in viscosity when homogenized. Furthermore, the homogenized gels were successfully incorporated in spray drying formulations for microencapsulation. The custom-designed microcapsule strength tester was successfully used and shown to possess the required sensitivity to discern batches of microcapsules containing volatiles to have different release profiles. Addition of homogenized gels strengthened the microcapsules only at high wall to core ratios with low mass-load alginate gels. High mass-load gels weaken the microcapsules, exhibiting a higher release at low stamping pressures and wrinkling on the microcapsules surface. PMID:26581772

  9. Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

    OpenAIRE

    B. Deepa; Eldho Abraham; Pothan, Laly A; Nereida Cordeiro; Marisa Faria; Sabu Thomas

    2016-01-01

    Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined. The results showed that the tensile modulus value of the nanocomposite films increased from 308 to 1403 MPa with increasing CNF content from 0% to 10%; however, it decreased with further...

  10. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. PMID:26453887

  11. Silk fibroin and sodium alginate blend: Miscibility and physical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Agostini de Moraes, Mariana; Silva, Mariana Ferreira; Weska, Raquel Farias; Beppu, Marisa Masumi, E-mail: beppu@feq.unicamp.br

    2014-07-01

    Films of silk fibroin (SF) and sodium alginate (SA) blends were prepared by solution casting technique. The miscibility of SF and SA in those blends was evaluated and scanning electron microscopy (SEM) revealed that SF/SA 25/75 wt.% blends underwent microscopic phase separation, resulting in globular structures composed mainly of SF. X-ray diffraction indicated the amorphous nature of these blends, even after a treatment with ethanol that turned them insoluble in water. Thermal analyses of blends showed the peaks of degradation of pristine SF and SA shifted to intermediate temperatures. Water vapor permeability, swelling capacity and tensile strength of SF films could be enhanced by blending with SA. Cell viability remained between 90 and 100%, as indicated by in vitro cytotoxicity test. The SF/SA blend with self-assembled SF globules can be used to modulate structural and mechanical properties of the final material and may be used in designing high performance wound dressing. - Highlights: • Blend films of fibroin and alginate were prepared with microscopic phase separation; • Self-assembled globular microdomains were mainly composed by fibroin; • It was possible to obtain a film with better mechanical and physical properties; • Blend films of fibroin and alginate represent a novel material in biomaterials field.

  12. A honeycomb composite of mollusca shell matrix and calcium alginate.

    Science.gov (United States)

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering. PMID:26700239

  13. Preparation of aminated chitosan/alginate scaffold containing halloysite nanotubes with improved cell attachment.

    Science.gov (United States)

    Amir Afshar, Hamideh; Ghaee, Azadeh

    2016-10-20

    The chemical nature of biomaterials play important role in cell attachment, proliferation and migration in tissue engineering. Chitosan and alginate are biodegradable and biocompatible polymers used as scaffolds for various medical and clinical applications. Amine groups of chitosan scaffolds play an important role in cell attachment and water adsorption but also associate with alginate carboxyl groups via electrostatic interactions and hydrogen bonding, consequently the activity of amine groups in the scaffold decreases. In this study, chitosan/alginate/halloysite nanotube (HNTs) composite scaffolds were prepared using a freeze-drying method. Amine treatment on the scaffold occurred through chemical methods, which in turn caused the hydroxyl groups to be replaced with carboxyl groups in chitosan and alginate, after which a reaction between ethylenediamine, 1-ethyl-3,(3-dimethylaminopropyl) carbodiimide (EDC) and scaffold triggered the amine groups to connect to the carboxyl groups of chitosan and alginate. The chemical structure, morphology and mechanical properties of the composite scaffolds were investigated by FTIR, CHNS, SEM/EDS and compression tests. The electrostatic attraction and hydrogen bonding between chitosan, alginate and halloysite was confirmed by FTIR spectroscopy. Chitosan/alginate/halloysite scaffolds exhibit significant enhancement in compressive strength compared with chitosan/alginate scaffolds. CHNS and EDS perfectly illustrate that amine groups were effectively introduced in the aminated scaffold. The growth and cell attachment of L929 cells as well as the cytotoxicity of the scaffolds were investigated by SEM and Alamar Blue (AB). The results indicated that the aminated chitosan/alginate/halloysite scaffold has better cell growth and cell adherence in comparison to that of chitosan/alginate/halloysite samples. Aminated chitosan/alginate/halloysite composite scaffolds exhibit great potential for applications in tissue engineering, ideally in

  14. Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase

    Directory of Open Access Journals (Sweden)

    Lorena Segale

    2016-01-01

    Full Text Available In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm. Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery.

  15. Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase.

    Science.gov (United States)

    Segale, Lorena; Giovannelli, Lorella; Mannina, Paolo; Pattarino, Franco

    2016-01-01

    In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm). Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery. PMID:27127680

  16. Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase

    Science.gov (United States)

    Segale, Lorena; Giovannelli, Lorella; Mannina, Paolo; Pattarino, Franco

    2016-01-01

    In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm). Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery. PMID:27127680

  17. Electrophoretic deposition of ZnO/alginate and ZnO-bioactive glass/alginate composite coatings for antimicrobial applications

    International Nuclear Information System (INIS)

    Two organic/inorganic composite coatings based on alginate, as organic matrix, and zinc oxide nanoparticles (n-ZnO) with and without bioactive glass (BG), as inorganic components, intended for biomedical applications, were developed by electrophoretic deposition (EPD). Different n-ZnO (1–10 g/L) and BG (1–1.5 g/L) contents were studied for a fixed alginate concentration (2 g/L). The presence of n-ZnO was confirmed to impart antibacterial properties to the coatings against gram-negative bacteria Escherichia coli, while the BG induced the formation of hydroxyapatite on coating surfaces thereby imparting bioactivity, making the coating suitable for bone replacement applications. Coating composition was analyzed by thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analyses. Scanning electron microscopy (SEM) was employed to study both the surface and the cross section morphology of the coatings. Polarization curves of the coated substrates made in cell culture media at 37 °C confirmed the corrosion protection function of the novel organic/inorganic composite coatings. - Highlights: • Organic–inorganic nanocomposite coatings fabricated by electrophoretic deposition • nZnO and bioactive glass containing alginate coatings exhibit antibacterial effect. • Bioactive character and anticorrosion function of coatings demonstrated

  18. Electrophoretic deposition of ZnO/alginate and ZnO-bioactive glass/alginate composite coatings for antimicrobial applications

    Energy Technology Data Exchange (ETDEWEB)

    Cordero-Arias, L.; Cabanas-Polo, S.; Goudouri, O.M. [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, D-91058 Erlangen (Germany); Misra, S.K. [Materials Science and Engineering, Indian Institute of Technology Gandhinagar, Ahmedabad 382424 (India); Gilabert, J. [Institute of Ceramics Materials (ITC), University Jaume I, Avenida Vicent SosBaynat, 12006 Castellon (Spain); Valsami-Jones, E. [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Sanchez, E. [Institute of Ceramics Materials (ITC), University Jaume I, Avenida Vicent SosBaynat, 12006 Castellon (Spain); Virtanen, S. [Institute for Surface Science and Corrosion (LKO, WW4), Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen (Germany); Boccaccini, A.R., E-mail: aldo.boccaccini@ww.uni-erlangen.de [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, D-91058 Erlangen (Germany)

    2015-10-01

    Two organic/inorganic composite coatings based on alginate, as organic matrix, and zinc oxide nanoparticles (n-ZnO) with and without bioactive glass (BG), as inorganic components, intended for biomedical applications, were developed by electrophoretic deposition (EPD). Different n-ZnO (1–10 g/L) and BG (1–1.5 g/L) contents were studied for a fixed alginate concentration (2 g/L). The presence of n-ZnO was confirmed to impart antibacterial properties to the coatings against gram-negative bacteria Escherichia coli, while the BG induced the formation of hydroxyapatite on coating surfaces thereby imparting bioactivity, making the coating suitable for bone replacement applications. Coating composition was analyzed by thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analyses. Scanning electron microscopy (SEM) was employed to study both the surface and the cross section morphology of the coatings. Polarization curves of the coated substrates made in cell culture media at 37 °C confirmed the corrosion protection function of the novel organic/inorganic composite coatings. - Highlights: • Organic–inorganic nanocomposite coatings fabricated by electrophoretic deposition • nZnO and bioactive glass containing alginate coatings exhibit antibacterial effect. • Bioactive character and anticorrosion function of coatings demonstrated.

  19. Speciation dependent radiotracer studies on chromium preconcentration using iron doped calcium alginate biopolymer

    International Nuclear Information System (INIS)

    The work aims to study the differential attitude of Ca-alginate (CA) and Fe-doped calcium alginate (Fe-CA) and towards Cr(III) and Cr (IV) so that, depending on the oxidation state of chromium effluent, environmentally sustainable methodologies can be prescribed for removal of chromium. Throughout the experiment 51Cr has been used as the precursor of stable chromium

  20. The role of pathogen-associated molecular patterns in inflammatory responses against alginate based microcapsules.

    NARCIS (Netherlands)

    Paredes, Genaro; de Haan, Bart; Faas, Marijke; de Vos, Paul

    2013-01-01

    Alginate-based microcapsules are used for immunoisolation of cells to release therapeutics on a minute-to-minute basis. Unfortunately, alginate-based microcapsules are suffering from varying degrees of success, which is usually attributed to differences in tissue responses. This results in failure o

  1. Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism

    Science.gov (United States)

    Horniblow, Richard D.; Dowle, Miriam; Iqbal, Tariq H.; Latunde-Dada, Gladys O.; Palmer, Richard E.

    2015-01-01

    Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease. PMID:26378798

  2. Three Alginate Lyases from Marine Bacterium Pseudomonas fluorescens HZJ216: Purification and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Liyan, Li [Ocean University of China, Qingdao, PRC; Jiang, Xiaolu [Ocean University of China, Qingdao, PRC; Wang, Peng [Ocean University of China, Qingdao, PRC; Guan, Huashi [Ocean University of China, Qingdao, PRC; Guo, Hong [ORNL

    2010-01-01

    Three alginate lyases (A, B, and C) from an alginate-degrading marine bacterium strain HZJ216 isolated from brown seaweed in the Yellow Sea of China and identified preliminarily as Pseudomonas fluorescens are purified, and their biochemical properties are described. Molecular masses of the three enzymes are determined by SDS-PAGE to be 60.25, 36, and 23 kDa with isoelectric points of 4, 4.36, and 4.59, respectively. Investigations of these enzymes at different pH and temperatures show that they are most active at pH 7.0 and 35 C. Alginate lyases A and B are stable in the pH range of 5.0 9.0, while alginate lyase C is stable in the pH range of 5.0 7.0. Among the metal ions tested, additions of Na+, K+, and Mg2+ ions can enhance the enzyme activities while Fe2+, Fe3+, Ba2+, and Zn2+ ions show inhibitory effects. The substrate specificity results demonstrate that alginate lyase C has the specificity for G block while alginate lyases A and B have the activities for both M and G blocks. It is the first report about extracellular alginate lyases with high alginate-degrading activity from P. fluorescens.

  3. Cultivable Alginate Lyase-Excreting Bacteria Associated with the Arctic Brown Alga Laminaria

    Directory of Open Access Journals (Sweden)

    Yu-Zhong Zhang

    2012-11-01

    Full Text Available Although some alginate lyases have been isolated from marine bacteria, alginate lyases-excreting bacteria from the Arctic alga have not yet been investigated. Here, the diversity of the bacteria associated with the brown alga Laminaria from the Arctic Ocean was investigated for the first time. Sixty five strains belonging to nine genera were recovered from six Laminaria samples, in which Psychrobacter (33/65, Psychromonas (10/65 and Polaribacter (8/65 were the predominant groups. Moreover, 21 alginate lyase-excreting strains were further screened from these Laminaria-associated bacteria. These alginate lyase-excreting strains belong to five genera. Psychromonas (8/21, Psedoalteromonas (6/21 and Polaribacter (4/21 are the predominant genera, and Psychrobacter, Winogradskyella, Psychromonas and Polaribacter were first found to produce alginate lyases. The optimal temperatures for the growth and algiante lyase production of many strains were as low as 10–20 °C, indicating that they are psychrophilic bacteria. The alginate lyases produced by 11 strains showed the highest activity at 20–30 °C, indicating that these enzymes are cold-adapted enzymes. Some strians showed high levels of extracellular alginate lyase activity around 200 U/mL. These results suggest that these algiante lyase-excreting bacteria from the Arctic alga are good materials for studying bacterial cold-adapted alginate lyases.

  4. Coatless alginate pellets as sustained-release drug carrier for inflammatory bowel disease treatment.

    Science.gov (United States)

    Md Ramli, Siti Hajar; Wong, Tin Wui; Naharudin, Idanawati; Bose, Anirbandeep

    2016-11-01

    Conventional alginate pellets underwent rapid drug dissolution and failed to exert colon targeting unless subjected to complex coating. This study designed coatless delayed-release oral colon-specific alginate pellets for ulcerative colitis treatment. Alginate pellets, formulated with water-insoluble ethylcellulose and various calcium salts, were prepared using solvent-free melt pelletization technique which prevented reaction between processing materials during agglomeration and allowed reaction to initiate only in dissolution. Combination of acid-soluble calcium carbonate and highly water-soluble calcium acetate did not impart colon-specific characteristics to pellets due to pore formation in fragmented matrices. Combination of moderately water-soluble calcium phosphate and calcium acetate delayed drug release due to rapid alginate crosslinking by soluble calcium from acetate salt followed by sustaining alginate crosslinking by calcium phosphate. The use of 1:3 ethylcellulose-to-alginate enhanced the sustained drug release attribute. The ethylcellulose was able to maintain the pellet integrity without calcium acetate. Using hydrophobic prednisolone as therapeutic, hydrophilic alginate pellets formulated with hydrophobic ethylcellulose and moderately polar calcium phosphate exhibited colon-specific in vitro drug release and in vivo anti-inflammatory action. Coatless oral colon-specific alginate pellets can be designed through optimal formulation with melt pelletization as the processing technology. PMID:27516284

  5. Jellyfish collagen and alginate: Combined marine materials for superior chondrogenesis of hMSC.

    Science.gov (United States)

    Pustlauk, W; Paul, B; Gelinsky, M; Bernhardt, A

    2016-07-01

    Marine, hybrid constructs of porous scaffolds from fibrillized jellyfish collagen and alginate hydrogel are mimicking both of the main tissue components of cartilage, thus being a promising approach for chondrogenic differentiation of human mesenchymal stem cells (hMSC). Investigating their potential for articular cartilage repair, the present study examined scaffolds being either infiltrated with an alginate-cell-suspension (ACS) or seeded with hMSC and embedded in alginate after cell adhesion (EAS). Hybrid constructs with 2×10(5) and 4.5×10(5)hMSC/scaffold were compared to hMSC encapsulated in pure alginate discs, both chondrogenically stimulated for 21days. Typical round, chondrocyte-like morphology was observed in pure alginate gels and ACS scaffolds, while cells in EAS were elongated and tightly attached to the collagen pores. Col 2 gene expression was comparable in all scaffold types examined. However, the Col 2/Col 1 ratio was higher for pure alginate discs and ACS scaffolds compared to EAS. In contrast, cells in EAS scaffolds displayed higher gene expression of Sox 9, Col 11 and ACAN compared to ACS and pure alginate. Secretion of sulfated glycosaminoglycans (sGAG) was comparable for ACS and EAS scaffolds. In conclusion hybrid constructs of jellyfish collagen and alginate support hMSC chondrogenic differentiation and provide more stable and constructs compared to pure hydrogels. PMID:27127044

  6. Synthesis and Characterization of Crosslinked Hydrogel Polyacrylamide (PAAM)-Co-Alginate Prepared by Gama Irradiation

    International Nuclear Information System (INIS)

    Crosslinked poly(acrylamide) (PAAM)-co-alginate hydrogels were prepared by gamma irradiation (γ-irradiation) and their conditions such as irradiation dose and alginate concentration were studied. PAAM-co-alginate was crosslinked to yield water sorption materials with various ability to absorb water (swelling) depending on the preparation conditions (e.g. γ-irradiation dosage>20 kGy) and alginate concentration (0.5 - 1 wt %). With an increase of γ-irradiation dosage and alginate concentration, the gels content and water absorption were increasing markedly. The swelling properties of hydrogel in urea and NaCl solution and the effect of temperature were also investigated. Intensity decreasing of functional goups of OH and NH2 in the IR spectrum indicated that IPN (Interpenetreting Network) structure occured in the network of hydrogels. The ability of hydrogel to absorp and retain a large amount of water suggested their possible uses in health care and agriculture. (author)

  7. Superabsorbent nanocomposite (alginate-g-PAMPS/MMT): synthesis, characterization and swelling behavior.

    Science.gov (United States)

    Yadav, Mithilesh; Rhee, Kyong Yop

    2012-09-01

    A superabsorbent composite (alginate-g-PAMPS/MMT) was prepared by graft copolymerization from alginate, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and Na+ montmorillonite (MMT) in an inert atmosphere. Effects of polymerization variables on water absorbency, including the content of Na+ montmorillonite, sodium alginate, N,N'-methylenebisacrylamide and AMPS, were studied. The introduced montmorillonite formed a loose and porous surface and improved the water absorbency of the alginate-g-PAMPS/MMT superabsorbent composite. Swelling behaviors of the superabsorbent composites in various cationic salt solutions (NaCl, CaCl2 and FeCl3) and anionic salt solutions (NaCl and Na2SO4) were also systematically investigated. The superabsorbent composite was further characterized using Fourier transform infrared spectroscopy (FTIR), rheology, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) taking alginate-g-PAMPS as a reference. PMID:24751026

  8. Genipin Cross-Linked Polymeric Alginate-Chitosan Microcapsules for Oral Delivery: In-Vitro Analysis

    Directory of Open Access Journals (Sweden)

    Hongmei Chen

    2009-01-01

    Full Text Available We have previously reported the preparation of the genipin cross-linked alginate-chitosan (GCAC microcapsules composed of an alginate core with a genipin cross-linked chitosan membrane. This paper is the further investigation on their structural and physical characteristics. Results showed that the GCAC microcapsules had a smooth and dense surface and a networked interior. Cross-linking by genipin substantially reduced swelling and physical disintegration of microcapsules induced by nongelling ions and calcium sequestrants. Strong resistance to mechanical shear forces and enzymatic degradation was observed. Furthermore, the GCAC membranes were permeable to bovine serum albumin and maintained a molecular weight cutoff at 70 KD, analogous to the widely studied alginate-chitosan, and alginate-poly-L-lysine-alginate microcapsules. The release features and the tolerance of the GCAC microcapsules in the stimulated gastrointestinal environment were also investigated. This GCAC microcapsule formulation offers significant potential as a delivery vehicle for many biomedical applications.

  9. Digital microfluidic three-dimensional cell culture and chemical screening platform using alginate hydrogels.

    Science.gov (United States)

    George, Subin M; Moon, Hyejin

    2015-03-01

    Electro wetting-on-dielectric (EWOD) digital microfluidics (DMF) can be used to develop improved chemical screening platforms using 3-dimensional (3D) cell culture. Alginate hydrogels are one common method by which a 3D cell culture environment is created. This paper presents a study of alginate gelation on EWOD DMF and investigates designs to obtain uniform alginate hydrogels that can be repeatedly addressed by any desired liquids. A design which allows for gels to be retained in place during liquid delivery and removal without using any physical barriers or hydrophilic patterning of substrates is presented. A proof of concept screening platform is demonstrated by examining the effects of different concentrations of a test chemical on 3D cells in alginate hydrogels. In addition, the temporal effects of the various chemical concentrations on different hydrogel posts are demonstrated, thereby establishing the benefits of an EWOD DMF 3D cell culture and chemical screening platform using alginate hydrogels. PMID:25945142

  10. Physical and chemical characterization of titanium-alginate samples for biomedical applications

    International Nuclear Information System (INIS)

    The sol-gel technique combined with powder metallurgy may be an alternative to produce titanium parts for bioengineering, with the advantage of eliminating the powder compaction step, which may introduce defects. The present work introduces a system consisted of titanium powder and sodium alginate suspension, which undergoes reticulation in contact with a calcium salt solution, obtaining titanium/calcium alginate hydrogel with granule morphology. The characterization of the raw materials and granules of calcium alginate and titanium/calcium alginate was performed by x-ray fluorescence spectroscopy and thermogravimetric analysis. The granules topography was analyzed by scanning electron microscopy/EDS. Titanium and sodium alginate chemical composition were adequate for use as raw materials, showing that the methodology used is suitable for processing titanium samples for further consolidation by sintering, in order to produce titanium parts. (author)

  11. Review: Efficacy of alginate supplementation in relation to appetite regulation and metabolic risk factors

    DEFF Research Database (Denmark)

    Jensen, Morten Georg; Pedersen, C; Kristensen, Mette Bredal;

    2013-01-01

    vehicle applied for alginate supplementation, the majority of animal and human studies suggest that alginate consumption does suppress satiety and to some extent energy intake. Only one long-term intervention trial found effects on weight loss. In addition, alginates seem to exhibit beneficial influence......This review provides a critical update on human and animal studies investigating the effect of alginate supplementation on appetite regulation, glycaemic and insulinemic responses, and lipid metabolism with discussion of the evidence on potential mechanisms, efficacy and tolerability. Dependent on...... on postprandial glucose absorption and insulin response in animals and humans. However, alginate supplementation was only found to have cholesterol-lowering properties in animals. Several mechanisms have been suggested for the positive effect observed, which involve delayed gastric emptying...

  12. A doxorubicin delivery system: Samarium/mesoporous bioactive glass/alginate composite microspheres.

    Science.gov (United States)

    Zhang, Ying; Wang, Xiang; Su, Yanli; Chen, Dongya; Zhong, Wenxing

    2016-10-01

    Samarium (Sm) incorporated mesoporous bioactive glasses (MBG) microspheres have been prepared using the method of alginate cross-linking with Ca(2+) ions. The in vitro bioactivities of Sm/MBG/alginate microspheres were studied by immersing in simulated body fluid (SBF) for various periods. The results indicated that the Sm/MBG/alginate microspheres have a faster apatite formation rate on the surface. To investigate their delivery properties further, doxorubicin (DOX) was selected as a model drug. The results showed that the Sm/MBG/alginate microspheres exhibit sustained DOX delivery, and their release mechanism is controlled by Fickian diffusion according the Higuchi model. In addition, the delivery of DOX from Sm/MBG/alginate microspheres can be dominated by changing the doping concentration of Sm and the values of pH microenvironment. These all revealed that this material is a promising candidate for the therapy of bone cancer. PMID:27287115

  13. Gelling process of sodium alginate with bivalent ions rich microsphere: Nature of bivalent ions

    Science.gov (United States)

    Mauri, Marco; Vicini, Silvia; Castellano, Maila

    2016-05-01

    In the paper we present a new approach for obtaining a controlled gelling process of sodium alginate, based on the quantity of bivalent ions rich alginate micro-beads added as crosslinkers. Typically, calcium ions are used in gelation of alginate solutions. In this study we present different gelling systems realized with alginate microspheres, made by electrospinning methodology, enriched with different bivalent ions (Ca2+, Ba2+ and Mg2+). The microspheres were characterized under the point of view of the morphology by OM and as the ions content. Realized gels were characterized in light of the amount of the ions added to the alginate solution, and in light of the different dimensions of the micro-beads, using rheological measurements to assess the variation in the storage modulus (G'), loss modulus (G″) and complex viscosity (η*).

  14. Physical and chemical characterization of titanium-alginate samples for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Morani, L.M.; Ribeiro, A.A.; Oliveira, M.V. de; Dantas, F.M.L., E-mail: marize.varella@int.gov.b [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil); Leao, M.H.M.R. [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica

    2010-07-01

    The sol-gel technique combined with powder metallurgy may be an alternative to produce titanium parts for bioengineering, with the advantage of eliminating the powder compaction step, which may introduce defects. The present work introduces a system consisted of titanium powder and sodium alginate suspension, which undergoes reticulation in contact with a calcium salt solution, obtaining titanium/calcium alginate hydrogel with granule morphology. The characterization of the raw materials and granules of calcium alginate and titanium/calcium alginate was performed by x-ray fluorescence spectroscopy and thermogravimetric analysis. The granules topography was analyzed by scanning electron microscopy/EDS. Titanium and sodium alginate chemical composition were adequate for use as raw materials, showing that the methodology used is suitable for processing titanium samples for further consolidation by sintering, in order to produce titanium parts. (author)

  15. Preparation of Biodegradable Silk Fibroin/Alginate Blend Films for Controlled Release of Antimicrobial Drugs

    Directory of Open Access Journals (Sweden)

    Yaowalak Srisuwan

    2013-01-01

    Full Text Available Silk fibroin (SF/alginate blend films have been prepared for controlled release of tetracycline hydrochloride, an antimicrobial model drug. The blend films were analysed by Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM, and UV-vis spectroscopy. The functional groups of the SF/alginate blends were monitored from their FTIR spectra. The homogeneity of the blend films was observed from SEM images. The dissolution and film transparency of the blend films depended on the SF/alginate blend ratio. The in vitro drug release profile of the blend films was determined by plotting the cumulative drug release versus time. It was found that the drug release significantly decreased as the SF/alginate blend ratio increased. The results demonstrated that the SF/alginate blend films should be a useful controlled-release delivery system for water-soluble drugs.

  16. Calcium alginate dressings promote healing of split skin graft donor sites.

    LENUS (Irish Health Repository)

    O'Donoghue, J M

    2012-02-03

    A prospective controlled trial was carried out to assess the healing efficacy of calcium alginate and paraffin gauze on split skin graft donor sites. Thirty patients were randomised to the calcium alginate group and 21 to the paraffin gauze group. The donor sites were assessed at 10 days post harvesting to determine if they were completely healed (100%) or not. Twenty one of the 30 patients dressed with calcium alginate were completely healed at day 10, while only 7\\/21 in the paraffin gauze group were healed (p < 0.05). There were two infections in the study, both occurring in the alginate group while there was no difference in dressing slippage between the two groups. Calcium alginate dressings provide a significant improvement in healing split skin graft donor sites.

  17. A conformational landscape for alginate secretion across the outer membrane of Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Jingquan [Trinity College, Dublin (Ireland); Rouse, Sarah L. [University of Oxford, South Parks Road, Oxford (United Kingdom); Li, Dianfan; Pye, Valerie E.; Vogeley, Lutz; Brinth, Alette R.; El Arnaout, Toufic [Trinity College, Dublin (Ireland); Whitney, John C.; Howell, P. Lynne [The Hospital for Sick Children, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada); Sansom, Mark S. P. [University of Oxford, South Parks Road, Oxford (United Kingdom); Caffrey, Martin, E-mail: martin.caffrey@tcd.ie [Trinity College, Dublin (Ireland)

    2014-08-01

    Crystal structures of the β-barrel porin AlgE reveal a mechanism whereby alginate is exported from P. aeruginosa for biofilm formation. The exopolysaccharide alginate is an important component of biofilms produced by Pseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cell via the outer membrane porin AlgE. X-ray structures of several AlgE crystal forms are reported here. Whilst all share a common β-barrel constitution, they differ in the degree to which loops L2 and T8 are ordered. L2 and T8 have been identified as an extracellular gate (E-gate) and a periplasmic gate (P-gate), respectively, that reside on either side of an alginate-selectivity pore located midway through AlgE. Passage of alginate across the membrane is proposed to be regulated by the sequential opening and closing of the two gates. In one crystal form, the selectivity pore contains a bound citrate. Because citrate mimics the uronate monomers of alginate, its location is taken to highlight a route through AlgE taken by alginate as it crosses the pore. Docking and molecular-dynamics simulations support and extend the proposed transport mechanism. Specifically, the P-gate and E-gate are flexible and move between open and closed states. Citrate can leave the selectivity pore bidirectionally. Alginate docks stably in a linear conformation through the open pore. To translate across the pore, a force is required that presumably is provided by the alginate-synthesis machinery. Accessing the open pore is facilitated by complex formation between AlgE and the periplasmic protein AlgK. Alginate can thread through a continuous pore in the complex, suggesting that AlgK pre-orients newly synthesized exopolysaccharide for delivery to AlgE.

  18. Alginate Encapsulation Parameters Influence the Differentiation of Microencapsulated Embryonic Stem Cell Aggregates

    Science.gov (United States)

    Wilson, Jenna L.; Najia, Mohamad Ali; Saeed, Rabbia; McDevitt, Todd C.

    2014-01-01

    Pluripotent embryonic stem cells (ESCs) have tremendous potential as tools for regenerative medicine and drug discovery, yet the lack of processes to manufacture viable and homogenous cell populations of sufficient numbers limits the clinical translation of current and future cell therapies. Microencapsulation of ESCs within microbeads can shield cells from hydrodynamic shear forces found in bioreactor environments while allowing for sufficient diffusion of nutrients and oxygen through the encapsulation material. Despite initial studies examining alginate microbeads as a platform for stem cell expansion and directed differentiation, the impact of alginate encapsulation parameters on stem cell phenotype has not been thoroughly investigated. Therefore, the objective of this study was to systematically examine the effects of varying alginate compositions on microencapsulated ESC expansion and phenotype. Pre-formed aggregates of murine ESCs were encapsulated in alginate microbeads composed of a high or low ratio of guluronic to mannuronic acid residues (High G and High M, respectively), with and without a poly-l-lysine (PLL) coating, thereby providing four distinct alginate bead compositions for analysis. Encapsulation in all alginate compositions was found to delay differentiation, with encapsulation within High G alginate yielding the least differentiated cell population. The addition of a PLL coating to the High G alginate prevented cell escape from beads for up to 14 days. Furthermore, encapsulation within High M alginate promoted differentiation toward a primitive endoderm phenotype. Taken together, the findings of this study suggest that distinct ESC expansion capacities and differentiation trajectories emerge depending on the alginate composition employed, indicating that encapsulation material physical properties can be used to control stem cell fate. PMID:24166004

  19. A conformational landscape for alginate secretion across the outer membrane of Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Crystal structures of the β-barrel porin AlgE reveal a mechanism whereby alginate is exported from P. aeruginosa for biofilm formation. The exopolysaccharide alginate is an important component of biofilms produced by Pseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cell via the outer membrane porin AlgE. X-ray structures of several AlgE crystal forms are reported here. Whilst all share a common β-barrel constitution, they differ in the degree to which loops L2 and T8 are ordered. L2 and T8 have been identified as an extracellular gate (E-gate) and a periplasmic gate (P-gate), respectively, that reside on either side of an alginate-selectivity pore located midway through AlgE. Passage of alginate across the membrane is proposed to be regulated by the sequential opening and closing of the two gates. In one crystal form, the selectivity pore contains a bound citrate. Because citrate mimics the uronate monomers of alginate, its location is taken to highlight a route through AlgE taken by alginate as it crosses the pore. Docking and molecular-dynamics simulations support and extend the proposed transport mechanism. Specifically, the P-gate and E-gate are flexible and move between open and closed states. Citrate can leave the selectivity pore bidirectionally. Alginate docks stably in a linear conformation through the open pore. To translate across the pore, a force is required that presumably is provided by the alginate-synthesis machinery. Accessing the open pore is facilitated by complex formation between AlgE and the periplasmic protein AlgK. Alginate can thread through a continuous pore in the complex, suggesting that AlgK pre-orients newly synthesized exopolysaccharide for delivery to AlgE

  20. Kinetics of Iododeoxyuridine release from sodium alginate hydrogel in vitro

    Institute of Scientific and Technical Information of China (English)

    XU Yong-hua; Mandar R Jagtap; ZHANG Dian-bo; YING Jun; Ronald C McGarry; Marc S. Mendonca; Gordon McLennan

    2006-01-01

    Objective To investigate the kinetics of Iododeoxyuridine (IUdR)release from sodium alginate hydrogel cross-linked with varying amounts of calcium chloride, and to optimize sustained release for further periadventitial I125-labeled IUdR delivery to suppress intimal hyperplasia following angioplasty in vivo.Methods Four hydrogels,composed of 0.16 mEq sodium alginate and 200 g IUdR, were cross-linked with calcium chloride to yield ion equivalence (IE) ratios (Calcium: alginate) of 3:1, 4:1, 5:1, or 6:1. 2 ml of normal saline was placed on top of each hydrogel and allowed to remain in contact at 37℃ for up to 30 days. At set time intervals, the concentration and amount of IUdR in the eluate were assayed by high performance liquid chromatography using UV detection and Water symmetry C18 column. The data for accumulated release rate and concentration in the eluate were calculated based on the calibration curve of peak area versus IUdR concentration. The hydrogel morphologic degradations were also observed. Results The hydrogels entrapped 92.9%, 98.6%, 98.4% and 98.6% of the IUdR with 3:1, 4:1, 5:1 and 6:1 IE ratios, respectively. IUdR concentration in eluates from 3:1 IE ratio hydrogel decreased faster than that from other hydrogels over time (P < 0.01). The 4:1, 5:1 and 6:1 IE ratio hydrogels produced more than 10 μm IUdR concentrations in eluates for the first 8 days, while the 3:1 IE ratio hydrogel for 4 days. IUdR release rates of the 4:1, 5:1 and 6:1 IE ratio hydrogels were very close, however they were lower than that of the 3:1 IE hydrogel in the first 48 hours (P < 0.05). At day 30, the 3:1 and 4:1 IE ratio hydrogels had 100% and 88% degradation, but no significant degradation was observed in the other hydrogels. Conclusion The sodium alginate hydrogel with 4:1 IE ratio exhibited an optimal IUdR sustained release and almost complete degradation in 30 days. (J Intervent Radiol,2006 , 15: 293-298)

  1. Surface modification of Ti-surfaces by alginate polyelectrolyte layers

    Czech Academy of Sciences Publication Activity Database

    Kubies, Dana; Pop-Georgievski, Ognen; Mázl Chánová, Eliška; Zemek, Josef; Neykova, Neda; Demianchuk, Roman; Houska, Milan; Filová, Elena; Bačáková, Lucie; Rypáček, František

    Liverpool : European Society for Biomaterials, 2014. P314. [Annual Conference European Society for Biomaterials /26./. 31.08.2014-03.09.2014, Liverpool] R&D Projects: GA MZd(CZ) NT13297; GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:68378271 ; RVO:67985823 Keywords : surface modification * titanium * alginate Subject RIV: CD - Macromolecular Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D); EI - Biotechnology ; Bionics (FGU-C)

  2. Impact of alginate concentration on the viability, cryostorage, and angiogenic activity of encapsulated fibroblasts.

    Science.gov (United States)

    Mohanty, Swetaparna; Wu, Yang; Chakraborty, Nilay; Mohanty, Pravansu; Ghosh, Gargi

    2016-08-01

    Cryopreservation or cryostorage of tissue engineered constructs can enhance the off-the shelf availability of these products and thus can potentially facilitate the commercialization or clinical translation of tissue engineered products. Encapsulation of cells within hydrogel matrices, in particular alginate, is widely used for fabrication of tissue engineered constructs. While previous studies have explored the cryopreservation response of cells encapsulated within alginate matrices, systematic investigation of the impact of alginate concentration on the metabolic activity and functionality of cryopreserved cells is lacking. The objective of the present work is to determine the metabolic and angiogenic activity of cryopreserved human dermal fibroblasts encapsulated within 1.0%, 1.5% and 2.0% (w/v) alginate matrices. In addition, the goal is to compare the efficacy of dimethyl sulfoxide (DMSO) and trehalose as cryoprotectant. Our study revealed that the concentration of alginate plays a significant role in the cryopreservation response of encapsulated cells. The lowest metabolic activity of the cryopreserved cells was observed in 1% alginate microspheres. When higher concentration of alginate was utilized for cell encapsulation, the metabolic and angiogenic activity of the cells frozen in the absence of cryoprotectants was comparable to that observed in the presence of DMSO or trehalose. PMID:27157752

  3. Controlled production of alginate nanocomposites with incorporated silver nanoparticles aimed for biomedical applications

    Directory of Open Access Journals (Sweden)

    Jovanović Željka

    2012-01-01

    Full Text Available Production of nanocomposite alginate microbeads with electrochemically synthesized silver nanoparticles (AgNPs based on electrostatic extrusion technique was investigated with respect to potentials for utilization in pharmaceutical and biomedical applications. It was shown that electrochemical synthesis of AgNPs results in reduction of practically all Ag+ ions present in the initial solution yielding stable Ag/alginate colloid solutions that were demonstrated to be suitable for sterilization, manipulation, and electrostatic extrusion with retention of AgNPs. Presence of AgNPs in alginate colloid solutions had negligible effects on the size of the produced Ag/alginate microbeads, which was chiefly determined by the applied electrostatic potential during the extrusion. On the other hand, incorporation of AgNPs within the alginate hydrogel induced slight changes in biomechanical properties determined in a biomimetic bioreactor, so that packed beds of nanocomposite Ag/alginate microbeads exhibited slightly higher dynamic compression modulus as compared to that of control alginate microbeads (154 ± 4 and 141 ± 2 kPa, respectively. On the other hand, equilibrium unconfined compression modulus was significantly lower for nanocomposite microbeads as compared to that of controls (34 ± 2 and 47 ± 0.5 kPa, respectively. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 i br. Eureka E!6749

  4. Manipulation and Characterization of Alginate Exo polysaccharides produced by Azotobacter Vinelandii

    International Nuclear Information System (INIS)

    Exo polysaccharides (EPS) have been found in a wide range of applications in food industry and in the biomedical field. In the present study, the effect of nutritional factors (carbon and nitrogen sources) and gamma irradiations on alginate production by Azotobacter vinelandii was investigated. To understand the direct and indirect relations among these variables, a two way factorial design experiment was set up. At low concentration of carbon source (≤ 20 g/l), the alginate yield was influenced by the type of nitrogen substrate and C/N ratio, whereas the role of these factors on alginate production was minimized at high concentration of carbon source (> 20 g/l). Batch fermentation of alginate exo polysaccharides was manipulated by maintaining the ph value of the cultures at 7 along the incubation period and reducing the agitation speed to 100 rpm after 24 h at the time of inoculation. This process succeeded to increase the alginate yield exponentially with time by 50%. Exposing A. vinelandii cells to gamma irradiation at dose level 0.5 kGy decreased their activity to synthesis alginate by 44%. The produced alginate was characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR) and differential scanning calorimeter (DSC).

  5. Alginate Production from Alternative Carbon Sources and Use of Polymer Based Adsorbent in Heavy Metal Removal

    Directory of Open Access Journals (Sweden)

    Çiğdem Kıvılcımdan Moral

    2016-01-01

    Full Text Available Alginate is a biopolymer composed of mannuronic and guluronic acids. It is harvested from marine brown algae; however, alginate can also be synthesized by some bacterial species, namely, Azotobacter and Pseudomonas. Use of pure carbohydrate sources for bacterial alginate production increases its cost and limits the chance of the polymer in the industrial market. In order to reduce the cost of bacterial alginate production, molasses, maltose, and starch were utilized as alternative low cost carbon sources in this study. Results were promising in the case of molasses with the maximum 4.67 g/L of alginate production. Alginates were rich in mannuronic acid during early fermentation independent of the carbon sources while the highest guluronic acid content was obtained as 68% in the case of maltose. The polymer was then combined with clinoptilolite, which is a natural zeolite, to remove copper from a synthetic wastewater. Alginate-clinoptilolite beads were efficiently adsorbed copper up to 131.6 mg Cu2+/g adsorbent at pH 4.5 according to the Langmuir isotherm model.

  6. Adsorption of Cu and Mn on covalently cross-linked alginate gel beads.

    Science.gov (United States)

    Gotoh, Takeshi; Matsushima, Keiei; Kikuchi, Ken-Ichi

    2004-04-01

    The covalently cross-linked alginate gel beads were prepared by the reactions of Ca(2+)-doped alginate gel beads, which were formed by spraying a viscous alginate solution into a calcium chloride solution, with cyanogen bromide and following 1,6-diaminohexane. The cross-linking of alginate matrix decreased the mean bead diameter by about 30% and made the beads durable in some extent under alkaline conditions. The adsorption of metal ions on the covalently cross-linked alginate gel beads was rapid and reached at equilibrium within 30 min at 25 degrees C. Adsorption isotherms of Cu(II), Mn(II), and Ca2+ on the beads possessed a stepwise shape, which was firstly determined by Rorrer et al. [Ind. Eng. Chem. Res. 32 (1993) 2170] for cross-linked chitosan gel beads and explained by a pore-blockage mechanism. Higher selectivity was determined against Cu(II) over Mn(II) and Ca2+, especially at a low concentration region. These metal adsorption profiles for the covalently cross-linked alginate gel beads was almost the same as those for the un-cross-linked beads, indicating that the cross-linking reactions were performed without interfering the adsorption characteristics of alginate gel beads. PMID:14720547

  7. Quantification of alginate by aggregation induced by calcium ions and fluorescent polycations.

    Science.gov (United States)

    Zheng, Hewen; Korendovych, Ivan V; Luk, Yan-Yeung

    2016-01-01

    For quantification of polysaccharides, including heparins and alginates, the commonly used carbazole assay involves hydrolysis of the polysaccharide to form a mixture of UV-active dye conjugate products. Here, we describe two efficient detection and quantification methods that make use of the negative charges of the alginate polymer and do not involve degradation of the targeted polysaccharide. The first method utilizes calcium ions to induce formation of hydrogel-like aggregates with alginate polymer; the aggregates can be quantified readily by staining with a crystal violet dye. This method does not require purification of alginate from the culture medium and can measure the large amount of alginate that is produced by a mucoid Pseudomonas aeruginosa culture. The second method employs polycations tethering a fluorescent dye to form suspension aggregates with the alginate polyanion. Encasing the fluorescent dye in the aggregates provides an increased scattering intensity with a sensitivity comparable to that of the conventional carbazole assay. Both approaches provide efficient methods for monitoring alginate production by mucoid P. aeruginosa. PMID:26408812

  8. Highly Concentrated Alginate-Gellan Gum Composites for 3D Plotting of Complex Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Ashwini Rahul Akkineni

    2016-04-01

    Full Text Available In tissue engineering, additive manufacturing (AM technologies have brought considerable progress as they allow the fabrication of three-dimensional (3D structures with defined architecture. 3D plotting is a versatile, extrusion-based AM technology suitable for processing a wide range of biomaterials including hydrogels. In this study, composites of highly concentrated alginate and gellan gum were prepared in order to combine the excellent printing properties of alginate with the favorable gelling characteristics of gellan gum. Mixtures of 16.7 wt % alginate and 2 or 3 wt % gellan gum were found applicable for 3D plotting. Characterization of the resulting composite scaffolds revealed an increased stiffness in the wet state (15%–20% higher Young’s modulus and significantly lower volume swelling in cell culture medium compared to pure alginate scaffolds (~10% vs. ~23%. Cytocompatibility experiments with human mesenchymal stem cells (hMSC revealed that cell attachment was improved—the seeding efficiency was ~2.5–3.5 times higher on the composites than on pure alginate. Additionally, the composites were shown to support hMSC proliferation and early osteogenic differentiation. In conclusion, print fidelity of highly concentrated alginate-gellan gum composites was comparable to those of pure alginate; after plotting and crosslinking, the scaffolds possessed improved qualities regarding shape fidelity, mechanical strength, and initial cell attachment making them attractive for tissue engineering applications.

  9. Entrapment of cross-linked cellulase colloids in alginate beads for hydrolysis of cellulose.

    Science.gov (United States)

    Nguyen, Le Truc; Lau, Yun Song; Yang, Kun-Lin

    2016-09-01

    Entrapment of enzymes in calcium alginate beads is a popular enzyme immobilization method. However, leaching of immobilized enzymes from the alginate beads is a common problem because enzyme molecules are much smaller than the pore size of alginate beads (∼200nm). To address this issue, we employ a millifluidic reactor to prepare cross-linked cellulase aggregate (XCA) colloids with a uniform size (∼300nm). Subsequently, these colloids are immobilized in calcium alginate beads as biocatalysts to hydrolyze cellulose substrates. By using fluorescent microscopy, we conclude that the immobilized XCA colloids distribute uniformly inside the beads and do not leach out from the beads after long-term incubation. Meanwhile, the pore size of the alginate beads is big enough for the cellulose substrates and fibers to diffuse into the beads for hydrolysis. For example, palm oil fiber and microcrystalline cellulose can be hydrolyzed within 48h and release reducing sugar concentrations up to 2.48±0.08g/l and 4.99±0.09g/l, respectively. Moreover, after 10 cycles of hydrolysis, 96.4% of the XCA colloids remain inside the alginate beads and retain 67% of the original activity. In contrast, free cellulase immobilized in the alginate beads loses its activity completely after 10 cycles. The strategy can also be used to prepare other types of cross-linked enzyme aggregates with high uniformity. PMID:27318817

  10. Terminal sterilization of alginate hydrogels: efficacy and impact on mechanical properties.

    Science.gov (United States)

    Stoppel, Whitney L; White, Joseph C; Horava, Sarena D; Henry, Anna C; Roberts, Susan C; Bhatia, Surita R

    2014-05-01

    Terminal, or postprocessing, sterilization of composite biomaterials is crucial for their use in wound healing and tissue-engineered devices. Recent research has focused on optimizing traditional biomaterial formulations to create better products for commercial and academic use which incorporate hydrophobic compounds or secondary gel networks. To use a hydrogel in a clinical setting, terminal sterilization is necessary to ensure patient safety. Lyophilization, gamma-irradiation, and ethylene oxide treatment all have negative consequences when applied to alginate scaffolds for clinical use. Here, we aim to find alternative terminal sterilization methods for alginate and alginate-based composite hydrogels which maintain the structure of composite alginate networks for use in biomedical applications. A thorough investigation of the effect of common sterilization methods on swollen alginate-based hydrogels has not been reported and therefore, this work examines autoclaving, ethanol washing, and ultraviolet light as sterilization techniques for alginate and alginate/Pluronic® F68 composite hydrogels. Preservation of structural integrity is evaluated using shear rheology and analysis of water retention, and efficacy of sterilization is determined via bacterial persistence within the hydrogel. Results indicate that ethanol sterilization is the best method of those investigated because ethanol washing results in minimal effects on mechanical properties and water retention and eliminates bacterial persistence. Furthermore, this study suggests that ethanol treatment is an efficacious method for terminally sterilizing interpenetrating networks or other composite hydrogel systems. PMID:24259507

  11. The enhancement of chondrogenesis of ATDC5 cells in RGD-immobilized microcavitary alginate hydrogels.

    Science.gov (United States)

    Yao, Yongchang; Zeng, Lei; Huang, Yuyang

    2016-07-01

    In our previous work, we have developed an effective microcavitary alginate hydrogel for proliferation of chondrocytes and maintenance of chondrocytic phenotype. In present work, we investigated whether microcavitary alginate hydrogel could promote the chondrogenesis of progenitor cells. Moreover, we attempted to further optimize this system by incorporating synthetic Arg-Gly-Asp peptide. ATDC5 cells were seeded into microcavitary alginate hydrogel with or without Arg-Gly-Asp immobilization. Cell Counting Kit-8 and live/dead staining were conducted to analyze cell proliferation. Real-time polymerase chain reaction (RT-PCR), hematoxylin and eosin, and Toluidine blue O staining as well as Western blot assay was performed to evaluate the cartilaginous markers at transcriptional level and at protein level, respectively. The obtained data demonstrated that Arg-Gly-Asp-immobilized microcavitary alginate hydrogel was preferable to promote the cell proliferation. Also, Arg-Gly-Asp-immobilized microcavitary alginate hydrogel improved the expression of chondrocytic genes including Collagen II and Aggrecan when compared with microcavitary alginate hydrogel. The results suggested that microcavitary alginate hydrogel could promote the chondrogenesis. And Arg-Gly-Asp would be promising to ameliorate this culture system for cartilage tissue engineering. PMID:27000189

  12. Crystallization and preliminary X-ray analysis of alginate importer from Sphingomonas sp. A1

    International Nuclear Information System (INIS)

    Alginate importer from Sphingomonas sp. A1 is a member of the ABC transporter superfamily that directly transports alginate polysaccharide into the cytoplasm. Crystals of alginate importer in complex with the periplasmic binding protein AlgQ2 diffracted X-rays to 3.3 Å resolution. Sphingomonas sp. A1 directly incorporates alginate polysaccharides through a ‘superchannel’ comprising a pit on the cell surface, alginate-binding proteins in the periplasm and an ABC transporter (alginate importer) in the inner membrane. Alginate importer, consisting of four subunits, AlgM1, AlgM2 and two molecules of AlgS, was crystallized in the presence of the binding protein AlgQ2. Preliminary X-ray analysis showed that the crystal diffracted to 3.3 Å resolution and belonged to space group P212121, with unit-cell parameters a = 72.5, b = 136.8, c = 273.3 Å, suggesting the presence of one complex in the asymmetric unit

  13. Surface modified alginate microcapsules for 3D cell culture

    Science.gov (United States)

    Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

    2016-06-01

    Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

  14. New alginic acid–atenolol microparticles for inhalatory drug targeting

    Energy Technology Data Exchange (ETDEWEB)

    Ceschan, Nazareth Eliana; Bucalá, Verónica [Planta Piloto de Ingeniería Química (PLAPIQUI), CONICET, Universidad Nacional del Sur (UNS), Camino La Carrindanga Km 7, 8000 Bahía Blanca (Argentina); Departamento de Ingeniería Química, UNS, Avenida Alem 1253, 8000 Bahía Blanca (Argentina); Ramírez-Rigo, María Verónica, E-mail: vrrigo@plapiqui.edu.ar [Planta Piloto de Ingeniería Química (PLAPIQUI), CONICET, Universidad Nacional del Sur (UNS), Camino La Carrindanga Km 7, 8000 Bahía Blanca (Argentina); Departamento de Biología, Bioquímica y Farmacia, UNS, San Juan 670, 8000 Bahía Blanca (Argentina)

    2014-08-01

    The inhalatory route allows drug delivery for local or systemic treatments in a noninvasively way. The current tendency of inhalable systems is oriented to dry powder inhalers due to their advantages in terms of stability and efficiency. In this work, microparticles of atenolol (AT, basic antihypertensive drug) and alginic acid (AA, acid biocompatible polyelectrolyte) were obtained by spray drying. Several formulations, varying the relative composition AT/AA and the total solid content of the atomized dispersions, were tested. The powders were characterized by: Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Powder X-ray Diffraction, while also the following properties were measured: drug load efficiency, flow properties, particles size and density, moisture content, hygroscopicity and morphology. The ionic interaction between AA and AT was demonstrated, then the new chemical entity could improve the drug targeting to the respiratory membrane and increase its time residence due to the mucoadhesive properties of the AA polymeric chains. Powders exhibited high load efficiencies, low moisture contents, adequate mean aerodynamic diameters and high cumulative fraction of respirable particles (lower than 10 μm). - Highlights: • Novel particulate material to target atenolol to the respiratory membrane was developed. • Crumbled microparticles were obtained by spray drying of alginic–atenolol dispersions. • Ionic interaction between alginic acid and atenolol was demonstrated in the product. • Amorphous solids with low moisture content and high load efficiency were produced. • Relationships between the feed formulation and the product characteristics were found.

  15. Diffusivity of Cu(2+) in calcium alginate gel beads.

    Science.gov (United States)

    Chen, D; Lewandowski, Z; Roe, F; Surapaneni, P

    1993-03-25

    A linear absorption model (LAM) is used to describe the process of metal binding to spherically shaped biopolymers particles. The LAM was solved using a numerical algorithm which calculates diffusivities of metal ion in biopolymer gels. It assumes attainment of rapid metal-biopolymer binding equilibrium accompanied by rate limiting diffusion of the metal ions through the gel. The model was tested using batch experiments in which copper (Cu(2+)) binding with calcium alginate beads was investigated. Biopolymer density in the beads was varied between 2% and 5%. The diffusion coefficient of Cu(2+) calculated from the LAM ranged from 1.19 x 10(-9) to 1.48 x 10(-9) m(2) s(-1) (average 1.31 +/- 0.21 x 10(-9) m(2) s(-1)), independent of biopolymer density. The LAM has theoretical advantages over the shrinking core model (shell progressive model). The latter calculated an unreasonable exponential increase in the diffusion coefficient as density of alginate polymer in the bead increased. PMID:18609618

  16. New alginic acid–atenolol microparticles for inhalatory drug targeting

    International Nuclear Information System (INIS)

    The inhalatory route allows drug delivery for local or systemic treatments in a noninvasively way. The current tendency of inhalable systems is oriented to dry powder inhalers due to their advantages in terms of stability and efficiency. In this work, microparticles of atenolol (AT, basic antihypertensive drug) and alginic acid (AA, acid biocompatible polyelectrolyte) were obtained by spray drying. Several formulations, varying the relative composition AT/AA and the total solid content of the atomized dispersions, were tested. The powders were characterized by: Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Powder X-ray Diffraction, while also the following properties were measured: drug load efficiency, flow properties, particles size and density, moisture content, hygroscopicity and morphology. The ionic interaction between AA and AT was demonstrated, then the new chemical entity could improve the drug targeting to the respiratory membrane and increase its time residence due to the mucoadhesive properties of the AA polymeric chains. Powders exhibited high load efficiencies, low moisture contents, adequate mean aerodynamic diameters and high cumulative fraction of respirable particles (lower than 10 μm). - Highlights: • Novel particulate material to target atenolol to the respiratory membrane was developed. • Crumbled microparticles were obtained by spray drying of alginic–atenolol dispersions. • Ionic interaction between alginic acid and atenolol was demonstrated in the product. • Amorphous solids with low moisture content and high load efficiency were produced. • Relationships between the feed formulation and the product characteristics were found

  17. Study of Alginate-Supported Ionic Liquid and Pd Catalysts

    Directory of Open Access Journals (Sweden)

    Eric Guibal

    2012-01-01

    Full Text Available New catalytic materials, based on palladium immobilized in ionic liquid supported on alginate, were elaborated. Alginate was associated with gelatin for the immobilization of ionic liquids (ILs and the binding of palladium. These catalytic materials were designed in the form of highly porous monoliths (HPMs, in order to be used in a column reactor. The catalytic materials were tested for the hydrogenation of 4-nitroaniline (4-NA in the presence of formic acid as hydrogen donor. The different parameters for the elaboration of the catalytic materials were studied and their impact analyzed in terms of microstructures, palladium sorption properties and catalytic performances. The characteristics of the biopolymer (proportion of β-D-mannuronic acid (M and α-L-guluronic acid (G in the biopolymer defined by the M/G ratio, the concentration of the porogen agent, and the type of coagulating agent significantly influenced catalytic performances. The freezing temperature had a significant impact on structural properties, but hardly affected the catalytic rate. Cellulose fibers were incorporated as mechanical strengthener into the catalytic materials, and allowed to enhance mechanical properties and catalytic efficiency but required increasing the amount of hydrogen donor for catalysis.

  18. Characterization of alginate-brushite in-situ hydrogel composites.

    Science.gov (United States)

    Dabiri, Seyed Mohammad Hossein; Lagazzo, Alberto; Barberis, Fabrizio; Farokhi, Mehdi; Finochio, Elisabetta; Pastorino, Laura

    2016-10-01

    In the present study alginate-brushite composite hydrogels were in-situ synthetized and characterized with respect to preparation parameters. Specifically, the influence of initial pH value and initial concentration of phosphate precursor on the in-situ fabrication of the composite hydrogel were taken into account. The composite hydrogels were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric (TGA, DTG) and differential thermal analysis (DTA). Finally, the cell viability tests were carried out (MTT) over the incubation time period of 3, 7, and 14days. The results revealed that the formation and the crystalline stability of brushite were highly dependent on the initial pH value. It was shown that as the pH reached to the value of 6, characteristics peaks of brushite appeared in the FTIR spectra. Besides, the XRD and thermal analysis results were in a good accordance with those of FTIR. In addition, the SEM images demonstrated that the plate like brushite was formed inside the alginate matrix. Also, a considerable impact of pH variation on the biocompatibility of samples was noticed so that the majority of samples especially those prepared in the acidic conditions were toxic. PMID:27287148

  19. Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing

    International Nuclear Information System (INIS)

    The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer–ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds’ critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering. (paper)

  20. Effects of alginate on frozen-thawed boar spermatozoa quality, lipid peroxidation and antioxidant enzymes activities.

    Science.gov (United States)

    Hu, Jinghua; Geng, Guoxia; Li, Qingwang; Sun, Xiuzhu; Cao, Hualin; Liu, Yawei

    2014-06-30

    Although alginate was reported to play an important role as free radical scavengers in vitro and could be used as sources of natural antioxidants, there was no study about the cryoprotective effects of alginate on boar spermatozoa freezing. The objective of this research was to evaluate the effects of different concentrations of alginate added to the freezing extenders on boar spermatozoa motility, plasma membrane integrity, acrosomal integrity, mitochondrial activities, lipid peroxidation and antioxidative enzymes activities (SOD and GSH-Px) after thawing. Alginate was added to the TCG extender to yield six different final concentrations: 0, 0.2, 0.4, 0.6, 0.8, and 1.0mg/mL. The semen extender supplemented with various doses of alginate increased (P<0.05) total motility. The spermatozoa plasma membrane integrity and mitochondrial activity were improved at four different concentrations: 0.4, 0.6, 0.8, 1.0mg/mL. The addition of alginate also provided significantly positive effect on post-thaw boar spermatozoa acrosomal integrity at concentrations of 0.6, 0.8, 1.0mg/mL, compared with that of the control (P<0.05). The freezing extenders with the presence of alginate led to higher SOD and GSH-Px activities and lower MDA levels, in comparison to the control (P<0.05). In summary, alginate exhibited a dose-related response on frozen-thawed boar spermatozoa motility, functional integrity and antioxidative capacity at appropriate concentrations. Therefore alginate could be employed as an effective cryoprotectant in boar spermatozoa cryopreservation. PMID:24814905

  1. Development of nanocomposites based on hydroxyapatite/sodium alginate: Synthesis and characterisation

    International Nuclear Information System (INIS)

    In this study, a novel method was used to produce a nanostructured composite consisting of hydroxyapatite and sodium alginate by varying the composition of sodium alginate. The structure, morphology, simulated body fluid response and mechanical properties of the synthesised nanocomposites were characterised. From X-ray diffraction analysis, an increase in crystallite size and degree of crystallinity with an increase in the composition of sodium alginate up to 1.5 wt.% was observed. Further, it was found to decrease with an increase in the composition of sodium alginate. A notable peak shift from 1635 to 1607 cm-1 and 1456 to 1418 cm-1 in the Fourier transform infrared spectra of the nanocomposite was observed towards the lower wave number side when compared with pure hydroxyapatite. It reveals a strong interaction between the positively charged calcium (Ca2+) and the negatively charged carboxyl group (COO-) in sodium alginate. Transmission electron microscopy images of pure hydroxyapatite showed a short nanorod-like morphology with an average particle size of 13 nm. Bioresorbability of the samples was observed by immersing them in simulated body fluid medium for 14 days to evaluate the changes in pH and Ca2+ ion strength. Microhardness shows an increasing trend with an increase in the composition of sodium alginate from 1.5 to 3.0 wt.%, which is similar to that in the density. - Research Highlights: → We have prepared nanohydroxyapatite/sodium alginate as a composite. → Effect of sodium alginate on the properties of nanohydrroxyapatite has been studied. → The sodium alginate ranges from 0 to 3.75 wt.% has been used. → Composites show improved biological and mechanical properties.

  2. Decolourisation of dyes under electro-Fenton process using Fe alginate gel beads

    International Nuclear Information System (INIS)

    Highlights: ► Catalytic activity of Fe alginate gel beads for the remediation of wastewater was tested. ► New electro-Fenton process for the remediation of polluted wastewater. ► Continuous dye treatment without operational problem with high removal. - Abstract: This study focuses on the application of electro-Fenton technique by use of catalytic activity of Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes. The Fe alginate gel beads were evaluated for decolourisation of two typical dyes, Lissamine Green B and Azure B under electro-Fenton process. After characterization of Fe alginate gel beads, the pH effect on the process with Fe alginate beads and a comparative study of the electro-Fenton process with free Fe and Fe alginate bead was done. The results showed that the use of Fe alginate beads increases the efficiency of the process; moreover the developed particles show a physical integrity in a wide range of pH (2–8). Around 98–100% of dye decolourisation was obtained for both dyes by electro-Fenton process in successive batches. Therefore, the process was performed with Fe alginate beads in a bubble continuous reactor. High color removal (87–98%) was attained for both dyes operating at a residence time of 30 min, without operational problems and maintaining particle shapes throughout the oxidation process. Consequently, the stable performance of Fe alginate beads opens promising perspectives for fast and economical treatment of wastewater polluted by dyes or similar organic contaminants.

  3. The Effect of Chitosan and Sodium Alginate on the Growth and Photosynthesis of Soybean

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seeu coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant. Sodium alginate and chitosan are high-molecular compound of two different kind,have the characteristic of promoting the crop growth. Using Sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics. The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.50 g @ kg-1

  4. A novel wound dressing material — fibrin–chitosan–sodium alginate composite sheet

    Indian Academy of Sciences (India)

    M Pandima Devi; M Sekar; M Chamundeswari; A Moorthy; G Krithiga; N Selva Murugan; T P Sastry

    2012-12-01

    The present study describes preparation and characterization of fibrin–chitosan–sodium alginate composite (F–C–SA) in sheet form. F–C–SA composite was prepared and characterized for its physicochemical properties like water absorption capacity, surface morphology, FTIR spectra and mechanical properties. The optimum quantities of fibrin, chitosan and sodium alginate to get better mechanical properties to composite were determined. FTIR spectrum confirmed the interaction between amino groups of chitosan, fibrin and sodium alginate and SEM studies revealed composite nature of the material.

  5. In-situ photopolymerization of monodisperse and discoid oxidized methacrylated alginate microgels in a microfluidic channel.

    Science.gov (United States)

    Wang, Shuo; Jeon, Oju; Shankles, Peter G; Liu, Yuan; Alsberg, Eben; Retterer, Scott T; Lee, Bruce P; Choi, Chang Kyoung

    2016-01-01

    We present a simple microfluidic technique to in-situ photopolymerize (by 365 nm ultraviolet) monodisperse oxidized methacrylated alginate (OMA) microgels using a photoinitiator (VA-086). By this technique, we generated monodisperse spherical OMA beads and discoid non-spherical beads with better shape consistency than ionic crosslinking methods do. We found that a high monomer concentration (8 w/v %), a high photoinitiator concentration (1.5 w/v %), and absence of oxygen are critical factors to cure OMA microgels. This photopolymerizing method is an alternative to current methods to form alginate microgels and is a simpler approach to generate non-spherical alginate microgels. PMID:26865901

  6. A Technology Platform to Test the Efficacy of Purification of Alginate

    Directory of Open Access Journals (Sweden)

    Genaro A. Paredes-Juarez

    2014-03-01

    Full Text Available Alginates are widely used in tissue engineering technologies, e.g., in cell encapsulation, in drug delivery and various immobilization procedures. The success rates of these studies are highly variable due to different degrees of tissue response. A cause for this variation in success is, among other factors, its content of inflammatory components. There is an urgent need for a technology to test the inflammatory capacity of alginates. Recently, it has been shown that pathogen-associated molecular patterns (PAMPs in alginate are potent immunostimulatories. In this article, we present the design and evaluation of a technology platform to assess (i the immunostimulatory capacity of alginate or its contaminants, (ii where in the purification process PAMPs are removed, and (iii which Toll-like receptors (TLRs and ligands are involved. A THP1 cell-line expressing pattern recognition receptors (PRRs and the co-signaling molecules CD14 and MD2 was used to assess immune activation of alginates during the different steps of purification of alginate. To determine if this activation was mediated by TLRs, a THP1-defMyD88 cell-line was applied. This cell-line possesses a non-functional MyD88 coupling protein, necessary for activating NF-κB via TLRs. To identify the specific TLRs being activated by the PAMPs, we use different human embryonic kidney (HEK cell-line that expresses only one specific TLR. Finally, specific enzyme-linked immunosorbent assays (ELISAs were applied to identify the specific PAMP. By applying this three-step procedure, we can screen alginate in a manner, which is both labor and cost efficient. The efficacy of the platform was evaluated with an alginate that did not pass our quality control. We demonstrate that this alginate was immunostimulatory, even after purification due to reintroduction of the TLR5 activating flagellin. In addition, we tested two commercially available purified alginates. Our experiments show that these commercial

  7. Digitization of dental alginate impression: Three-dimensional evaluation of point cloud.

    Science.gov (United States)

    Kim, So-Ri; Lee, Wan-Sun; Kim, Woong-Chul; Kim, Hea-Young; Kim, Ji-Hwan

    2015-01-01

    The purpose of this study was to evaluate the digitization of alginate impressions by analyzing differences between the scan data of two types of impressions (alginate and rubber) taken from the master die and the scan data for the master die. The master die and impressions were digitized using a dental laser scanner (7 series, Dental Wings, Montreal, Canada). The crown portion of the abutment teeth in the digital data of 20 impressions was divided into three regions: cervical surface, middle surface, and occlusal surface. An independent t-test showed a significant difference (pdigitization of alginate impressions in the future. PMID:26632232

  8. Purification and Characterization of Alginate Lyase from Marine Vibrio sp. YWA

    Institute of Scientific and Technical Information of China (English)

    Yuan-Hong WANG; Guang-Li YU; Xin-Min WANG; Zhi-Hua LV; Xia ZHAO; Zhi-Hong WU; Wei-Shang JI

    2006-01-01

    Extracellular alginate lyase secreted by marine Vibrio sp. YWA, isolated from decayed Laminaria japonica, was purified by a combination of ammonium sulfate precipitation and diethylaminoethyl that the molecular mass of alginate lyase was approximately 62.5 kDa, with an optimal pH and temperature at pH 7.0 and 25 ℃C, respectively. Km was e enzyme was enhanced by EDTA and Zn2+, but inhibited by Ba2+.The substrates specificity analysis shows that it was specific for hydrolyzing poly-β-D-1,4-mannuronate in alginate

  9. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    Science.gov (United States)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  10. Optimization of culturing condition and medium composition for the production of alginate lyase by a marine Vibrio sp. YKW-34

    Science.gov (United States)

    Fu, Xiaoting; Lin, Hong; Kim, Sang Moo

    2008-02-01

    Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the production of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL-1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25°C. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had negative effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had positive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of alginate lyase production under the optimized condition was described. The optimal harvest time was 48 h.

  11. Investigation on the biomimetic influence of biopolymers on calcium phosphate precipitation-Part 1: Alginate

    International Nuclear Information System (INIS)

    The understanding of how macromocules act in precipitation of inorganic phases is the key knowledge that is needed to establish the foundation to mimic nature and produce materials with high mechanical modulus besides outstanding optical and thermal properties. This study investigated how addition of small amounts of alginate (7-70 ppm), that presents many carboxylic groups, affects phase distribution and morphology of calcium phosphates, obtained through precipitation and further submitted to calcination and sintering. The results lead to the conclusion that alginate action is dynamic, where alginate molecules act as templates to nucleation, and most of the biopolymer remains in solution even when all calcium phosphate has precipitated. However, despite the effect on phase composition being mainly related to the system's kinetics, alginate does present thermodynamic interaction with the precipitates. It is probable that it acts by reducing the free energy of nucleation, as in heterogeneous nucleation processes.

  12. Synthesis and characterization of chitosan impregnated calcium alginate beads for removal of uranium from aquatic stream

    International Nuclear Information System (INIS)

    The present study was conducted to study the feasibility of chitosan impregnated calcium alginate beads (Cal-Alg-Chi) to sorb the excess uranium from the aquatic stream. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). The optimal composition of calcium alginate chitosan beads is 4 % (wt/vol) alginate gel having 5% loading of chitosan. The nature and morphology of pure and uranium sorbed calcium alginate chitosan beads were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and attenuated total reflectance Fourier transform infrared spectroscopy (ATRFTIR). The results of batch sorption experiments suggest that Cal-Alg-Chi beads are very effective for removal of uranium in the pH range of 2.0-5.0 and sorption is more than 80 % in the concentration range of 1-100 mgL-1

  13. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    Directory of Open Access Journals (Sweden)

    Uzaşçı Sesil

    2014-07-01

    Full Text Available Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI adsorption capacity determined from Langmuir isotherm was 36.5 mg/g dry alginate beads. Our study suggests that barium alginate beads can be used as cost-effective and efficient adsorbents for the removal of chromium (VI from contaminated waters.

  14. Microfluidic fabrication of shape-tunable alginate microgels: effect of size and impact velocity.

    Science.gov (United States)

    Hu, Yuandu; Azadi, Glareh; Ardekani, Arezoo M

    2015-04-20

    We report on a capillary-based microfluidic platform for the fabrication of non-spherical sodium alginate microgels. The sodium alginate droplets were crosslinked off-chip in a mixture of barium acetate and glycerol solution. Novel morphologies such as tear drop, lamp-like, mushroom-like, double-dimpled and bowl-like microgels were fabricated by controlling the size, impact velocity (at the crosslinking solution/oil interface), and concentration of sodium alginate solution. We monitored the microscale deformation process in situ at the interface and proposeed a deformation mechanism resulting in unique morphologies. Additionally, we constructed microgel superstructures by assembling the non-spherical alginate microgels to spherical poly(N-isopropylacrylamide) (pNIPAAm) microgels via electrostatic interaction. PMID:25662685

  15. Modeling of the reticulation kinetics of alginate/pluronic blends for biomedical applications.

    Science.gov (United States)

    Barba, Anna A; Lamberti, Gaetano; Rabbia, Luca; Grassi, Mario; Larobina, Domenico; Grassi, Gabriele

    2014-04-01

    In this work, blends of alginate/pluronic (F127) for biomedical applications were investigated. In particular, the kinetics of alginate chain reticulation by bivalent cations was studied by experimental and modeling approaches. Two kinds of sodium alginate were tested to obtain hard gel films. The thicknesses of the reticulated alginate films were measured as function of the exposure time and of the reticulating copper (Cu(2+)) solution concentration. The kinetics was described by a proper model able to reproduce the experimental data. The model parameters, evaluated based on the measurements of thicknesses as function of Cu(2+) concentration and exposure time, were further validated by comparing the prediction of the model with another set of independent measurement; here, the depletion of Cu(2+) ions in the conditioning solution above the reacting gel is measured as function of time. The tuned model could be used in the description of the future applications of the blends. PMID:24582256

  16. Alginate production by a mutant strain of azotobacter vinelandii using shake flask fermentation

    International Nuclear Information System (INIS)

    The present study describes the improvement of parent strain of Azotobacter vinelandii NRRL-14641 for enhanced alginate production using shake flask fermentation. Results indicated that a mutant A. vinelandii EMS-45 obtained after EMS treatment gave 1.55 fold better alginate productions than that of the parent strain. Different cultural conditions were employed to optimize the polymer production in the fermentation broth. It was noted that maximum alginate production (6.17 g/l) was obtained with nitrogen rich phosphate limited medium (NRP) after 110 h of incubation period. The incubation temperature 30 deg. C, pH 7.0, agitation intensity 200 rpm, carbon and nitrogen source were also optimized and sucrose and peptone were found as the best to support 1.55 fold higher alginate than that in un-optimized medium. (author)

  17. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    Science.gov (United States)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  18. Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae

    DEFF Research Database (Denmark)

    Laue, H.; Schenk, A.; Li, H.; Lambertsen, L.; Neu, T.R.; Molin, Søren; Ulrich, M.S.

    2006-01-01

    , levansucrase, occurred mainly during early exponential growth of both planktonic and sessile cells. Thus, accumulation of levan in biofilm voids hints to a function as a nutrient storage source for later stages of biofilm development. The presence of a third EPS besides levan and alginate was indicated by......Exopolysaccharides (EPSs) play important roles in the attachment of bacterial cells to a surface and/or in building and maintaining the three-dimensional, complex structure of bacterial biofilms. To elucidate the spatial distribution and function of the EPSs levan and alginate during biofilm...... formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser...

  19. PROMOTIVE EFFECT OF IRRADIATED SODIUM ALGINATE ON SEED GERMINATION CHARACTERISTICS OF FENNEL (FOENICULUM VULGARE MILL.)

    OpenAIRE

    Mohd. Idrees; M. Naeem; Tariq Aftab; Nadeem Hashmi; M. Masroor A. Khan; Moinuddin; Lalit Varshney

    2012-01-01

    Radiolytically derived oligomers of sodium alginate are considered to act as signal molecules, affecting growth, development and defense mechanisms of plants through gene regulation. Since germination is a critical stage in the life cycle of plants, the objective of this study was to determine the effect of irradiated sodium alginate (ISA) on the characteristics of seed germination of Foeniculum vulgare Mill. Soaking the seeds in an aqueous solution of ISA showed significant improvement in va...

  20. Physical evaluation of biodegradable films of calcium alginate plasticized with polyols

    OpenAIRE

    A. A. Santana; T. G. Kieckbusch

    2013-01-01

    The influence of different polyols as plasticizers of alginate films on their physical attributes like moisture content, soluble mass in water, water uptake, water vapor permeability, opacity and mechanical properties were determined and the results discussed based on scanning electron microscopy observations and glass transition temperature. The alginate films were obtained by casting, using three different gramatures. Calcium crosslinked and non-reticulated films were considered. The films ...

  1. Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices

    OpenAIRE

    Marita Westhrin; Minli Xie; Olderøy, Magnus Ø.; Pawel Sikorski; Strand, Berit L; Therese Standal

    2015-01-01

    Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and ...

  2. Effect of Carboxymethyl Cellulose and Alginate Coating Combined with Brewer Yeast on Postharvest Grape Preservation

    OpenAIRE

    Zhang Shaoying; Ren Yinzhe

    2013-01-01

    The effect of carboxymethyl cellulose and alginate coating combined with brewer yeast on postharvest grape preservation was investigated. The postharvest grapes were coated with 2% of alginate and 3% of carboxymethyl cellulose combined with 1.5×109 CFU/mL of brewer yeast. The combined treatment samples showed good sensory character on day 13 compared with control samples or only coated samples. The increase of weight loss and decrease of total soluble solids of combined treatment grapes were ...

  3. Granular gel support-enabled extrusion of three-dimensional alginate and cellular structures.

    Science.gov (United States)

    Jin, Yifei; Compaan, Ashley; Bhattacharjee, Tapomoy; Huang, Yong

    2016-01-01

    Freeform fabrication of soft structures has been of great interest in recent years. In particular, it is viewed as a critical step toward the grand vision of organ printing-the on-demand design and fabrication of three-dimensional (3D) human organ constructs for implantation and regenerative medicine. The objective of this study is to develop a novel granular gel support material-enabled, two-step gelation-based 'printing-then-gelation' approach to fabricate 3D alginate structures using filament extrusion. Specifically, a granular Carbopol microgel bath holds the ungelled alginate structure being extruded, avoiding the instantaneous gelation of each printed layer as well as resultant surface tension-induced nozzle clogging. Since Carbopol microgels react with multivalent cations, which are needed for alginate crosslinking, gelatin is introduced as a sacrificial material to make an alginate and gelatin bioink for extrusion, which gels thermally (step-one gelation) to initially stabilize the printed structure for removal from Carbopol. Then gelatin is melted and diffused away while alginate is ionically crosslinked in a 37 °C calcium chloride bath (step-two gelation), resulting in an alginate structure. The proposed 'printing-then-gelation' approach works for alginate structure fabrication, and it is also applicable for the printing of cellular constructs and other similar homogeneous soft structures using a two-step or even multi-step approach. The main conclusions are: (1) 0.8% (w/v) Carbopol bath with a neutral pH value may be most suitable for soft structure printing; (2) it is most effective to use a 0.9% (w/v) NaCl solution to facilitate the removal of residual Carbopol; and (3) alginate structures fabricated using the proposed approach demonstrate better mechanical properties than those fabricated using the conventional 'gelation-while-printing' approach. PMID:27257095

  4. Design and performance of a sericin-alginate interpenetrating network hydrogel for cell and drug delivery

    OpenAIRE

    Yeshun Zhang; Jia Liu; Lei Huang; Zheng Wang; Lin Wang

    2015-01-01

    Although alginate hydrogels have been extensively studied for tissue engineering applications, their utilization is limited by poor mechanical strength, rapid drug release, and a lack of cell adhesive ability. Aiming to improve these properties, we employ the interpenetrating hydrogel design rationale. Using alginate and sericin (a natural protein with many unique properties and a major component of silkworm silk), we develop an interpenetrating polymer network (IPN) hydrogel comprising inter...

  5. Physicochemical properties of radiation-sterilized honey alginate wound dressing for exudating wounds

    International Nuclear Information System (INIS)

    Honey is a well-known natural cure in promoting healing of wounds. Alginate, on the other hand, is a polysaccharide with pharmaceutical applications such as wound dressing and control release drugs. Calcium-alginate wound dressings have a gel-forming capability. in that, upon ion exchange between calcium ions in the dressing, and sodium ions in wound fluid, the dressing transforms into a gel. Cross-linked alginate gels can absorb would fluid, and also maintain a moist environment to the wound area. Combined with anti-microbial properties of honey and absorption and gelling properties of alginate, a honey alginate wound dressing is developed and irradiated for sterility. Its physicochemical properties are then analyzed. The honey-alginate wound dressing has lower pH (4.40±0.02) than alginate alone dressings (5.40±0.04) which is more favorable for wound healing. The dressing also has low moisture content (10.25±1.11%). Analysis of moisture vapour transmission rate shows a general increase with time for 48 hours. The wound dressing also has an absorbency of 19.00±1.80 g/100 cm2 with a gel fraction of 18.44±0.63%. The rate of absorption analysis, meanwhile, shows a very rapid absorption rate upon exposure to wound fluid. After some time, a decrease in rate is observed which is accounted to the release of honey to the wound environment. For tensile strength, irradiation causes an effect in tensile strength in machine direction but is insignificant for cross machine direction. Physicochemical properties of the radiation-sterilized honey alginate wound dressing e.g. acidic pH, absorbency, moisture vapor permeability and absorption rate ascertain its characteristic as a good wound dressing for exudating wounds. Its low moisture content, meanwhile, allows for longer shelf-life of the developed product. (author)

  6. Effects of ionizing radiation on the extraction yield and viscosity of alginate

    International Nuclear Information System (INIS)

    A seaweed Ecklonia cava from Jeju island was irradiated with 0.1-6 Mrad of gamma-rays and the yield and viscosity characteristics of alginates from it were examined. Irradiation below 1 Mrad dose brought about a 70% increase in the yield while higher doses caused slight decreases. Viscosity behavior of alginates below 0.5 Mrad dose was not altered while the viscosity decreased markedly above 1 Mrad dose, likely due to the depolymerization. (author)

  7. Heterogeneous Fenton oxidation of ofloxacin drug by iron alginate support.

    Science.gov (United States)

    Titouhi, Hana; Belgaied, Jamel-Eddine

    2016-08-01

    A new catalytic wet peroxide oxidation of ofloxacin antibiotic is presented in this work. The removal was achieved using a biodegradable sodium alginate-iron material. Several parameters were studied such as iron content, drying duration of the catalytic support, temperature, solid amount and initial drug concentration. The process showed a strong oxidative ability; at optimum conditions, a nearly complete removal of the drug (around 98%) has been reached after three h of treatment. A relatively low decrease of support activity (around 10%) has been observed after three successive oxidation runs and a low iron leaching has been detected (1.2% of the incorporated quantity). The removal of the substrate has been also examined in the absence of hydrogen peroxide in order to discriminate between the contributions of simple adsorption and oxidation processes in the drug disappearance. We also discussed the influence of the studied experimental parameters on the removal kinetic. PMID:26752017

  8. Microencapsulation of eugenol by gelatin-sodium alginate complex coacervation

    Directory of Open Access Journals (Sweden)

    Ujwala Shinde

    2011-01-01

    Full Text Available Present study describes microencapsulation of eugenol using gelatin-sodium alginate complex coacervation. The effects of core to coat ratio and drying method on properties of the eugenol microcapsules were investigated. The eugenol microcapsules were evaluated for surface characteristics, micromeritic properties, oil loading and encapsulation efficiency. Eugenol microcapsules possessed good flow properties, thus improved handling. The scanning electron photomicrographs showed globular surface of microcapsules prepared with core: coat ratio1:1.The treatment with dehydrating agent isopropanol lead to shrinking of microcapsule wall with cracks on it. The percent oil loading and encapsulation efficiency increased with increase in core: coat ratio whereas treatment with dehydrating agent resulted in reduction in loading and percent encapsulation efficiency of eugenol microcapsules.

  9. Chiroptical characterization of homopolymeric block fractions in alginates.

    Science.gov (United States)

    Martínez-Gómez, Fabián; Mansilla, Andrés; Matsuhiro, Betty; Matulewicz, María C; Troncoso-Valenzuela, Marcos A

    2016-08-01

    Homopolymannuronic and homopolyguluronic fractions were obtained by partial hydrolysis of the alkaline extracts from the brown seaweeds Ascoseira mirabilis, Desmarestia menziessi, Desmarestia ligulata and Durvillaea sp. collected in southern Chile. Full characterization of the fractions was achieved by FT-IR and NMR spectroscopy. Total hydrolysis with 90% formic acid of the homopolymeric fractions allowed the preparation of mannuronic and guluronic acids. Both monomers and homopolymeric fractions as neutral salts were studied by CD and ORD. Chiroptical spectra were similar in shape and sign to those previously published in the literature, and permitted to assign D configuration to mannuronic acid and L configuration to guluronic acid in alginic acids. Specific optical rotation values at the sodium D light for the homopolymannuronic (∼-100°) and homopolyguluronic (∼-110°) acid fractions were obtained. These high negative values are proposed for the assignment of the absolute configuration of monomers in homopolymeric fractions. PMID:27112854

  10. Butyl acetate synthesis using immobilized lipase in calcium alginate beads

    International Nuclear Information System (INIS)

    The esterification reaction of acetic acid and n-butanol using immobilized lipase encapsulated in calcium alginate beads (Lipase - CAB) and in chitosan coated calcium alginate beads (Lipase-CCAB) in n-hexane under mild reaction conditions were studied. Effects of temperature and substrate concentration (acetic acid and n-butanol) using Lipase - CAB, Lipase - CCAB and free lipase on the esterification reaction and their thermal stability towards esterification reaction were investigated. Results of temperature studies showed that the butyl acetate conversion increased with increase of temperature and reached the highest yield of about 70% around 50 degree Celsius for both immobilized systems but the yield of product catalyzed by free enzyme decreased as temperature was increased. Thermal stabilities studies showed that the Lipase-CCAB and Lipase-CAB were stable throughout the temperature range of 30-60 degree Celsius. However, free lipase became less stable at temperatures higher than 50 degree Celsius. The substrates, n-butanol and acetic acid exerted different effects on the esterification reaction and the reaction was favoured by higher acetic acid concentration than butanol. Kinetics parameters, Km and Vmax values for both substrates and the specific activities of the three enzyme system were also determined. The beads morphology was examined using SEM. Batch-wise operational stability studies for both immobilized systems demonstrated that the immobilized lipase performed better in the batch wise reactor system than the continuous bioreactor system and that the immobilized lipase remained active for at least 5 cycles of batch wise esterification reactions. (author)

  11. Alginate based hydrogel as a potential biopolymeric carrier for drug delivery and cell delivery systems: present status and applications.

    Science.gov (United States)

    Giri, Tapan Kumar; Thakur, Deepa; Alexander, Amit; Ajazuddin; Badwaik, Hemant; Tripathi, Dulal Krishna

    2012-11-01

    Alginate is a non-toxic, biocompatible and biodegradable natural polymer with a number of peculiar physicochemical properties for which it has wide applications in drug delivery and cell delivery systems. Hydrogel formation can be obtained by interactions of anionic alginates with multivalent inorganic cations by simple ionotropic gelation method. Hydrophilic polymeric network of three dimensional cross linked structures of hydrogels absorb substantial amount of water or biological fluids. Among the numerous biomaterials used for hydrogel formation alginate has been and will continue to be one of the most important biomaterial. Therefore, in view of the vast literature support, we focus in this review on alginate - based hydrogel as drug delivery and cell delivery carriers for biomedical applications. Various properties of alginates, their hydrogels and also various techniques used for preparing alginate hydrogels have been reviewed. PMID:22998675

  12. Assessments of injectable alginate particle-embedded fibrin hydrogels for soft tissue reconstruction

    International Nuclear Information System (INIS)

    Soft tissue reconstruction is often needed after massive traumatic damage or cancer removal. In this study, we developed a novel hybrid hydrogel system consisting of alginate particles and a fibrin matrix that could maintain tissue volume long term. Alginate particles were fabricated by mixing 5% alginate with a 20 mM calcium solution. Cells and these alginate particles were then embedded in fibrin (alginate–fibrin) hydrogels using a dual syringe mixer. Cell–hydrogel constructs were evaluated in terms of cell survival and proliferation in the constructs in vitro. The results indicated that cellular viability, spreading and proliferation in the alginate–fibrin hydrogels were significantly higher compared to constructs fabricated with fibrin or alginate only. In vivo explants showed that cells contained within fibrin-only hydrogels did not contribute to neo-tissue formation, and the fibrin was fully degraded within a 12 week period. In the alginate–fibrin system, higher cellularity and vascular ingrowth were observed in vivo. This resulted in neo-tissue formation in the alginate–fibrin hydrogels. These results demonstrate that fibrin may enhance cell proliferation and accelerate the formation of extracellular matrix proteins in the alginate–fibrin system, while the alginate particles could contribute to volume retention. This injectable hybrid system composed of degradable and non-degradable hydrogels may be a preferable approach to the repair of soft tissue defects. (paper)

  13. Diffusion of sodium alginate in aqueous solutions at T = 298.15 K

    International Nuclear Information System (INIS)

    Highlights: • Mutual diffusion coefficients of sodium alginate in aqueous solutions. • Influence of the thermodynamic and kinetic factors on the variation of the mutual diffusion coefficients. • Estimation of the hydrodynamic radius of ion alginate. - Abstract: Taylor dispersion technique was used for measuring mutual diffusion coefficients of sodium alginate aqueous solutions at T = 298.15 K, by using as carrier stream solution both pure water and solutions of this polyelectrolyte at a slightly different concentration. The limiting values found at infinitesimal ionic strength, D0, were determined by extrapolating to c → 0. These studies were complemented by molecular mechanics calculations. From the experimental data, it was possible to estimate both the limiting conductivity and the tracer diffusion coefficient values for the alginate anion, and the hydrodynamic radius of the sodium alginate (NaC6H7O6), as well as to discuss the influence of the kinetic, thermodynamic and viscosity factors on the diffusion of sodium alginate in aqueous solutions at finite concentrations. Thus, the aim of our innovative research is to contribute to a better understanding of the structure and the thermodynamic behavior of these polymeric systems in solution and supplying the scientific and technological communities with data on these important parameters in solution transport processes

  14. In vitro fermentation of alginate and its derivatives by human gut microbiota.

    Science.gov (United States)

    Li, Miaomiao; Li, Guangsheng; Shang, Qingsen; Chen, Xiuxia; Liu, Wei; Pi, Xiong'e; Zhu, Liying; Yin, Yeshi; Yu, Guangli; Wang, Xin

    2016-06-01

    Alginate (Alg) has a long history as a food ingredient in East Asia. However, the human gut microbes responsible for the degradation of alginate and its derivatives have not been fully understood yet. Here, we report that alginate and the low molecular polymer derivatives of mannuronic acid oligosaccharides (MO) and guluronic acid oligosaccharides (GO) can be completely degraded and utilized at various rates by fecal microbiota obtained from six Chinese individuals. However, the derivative of propylene glycol alginate sodium sulfate (PSS) was not hydrolyzed. The bacteria having a pronounced ability to degrade Alg, MO and GO were isolated from human fecal samples and were identified as Bacteroides ovatus, Bacteroides xylanisolvens, and Bacteroides thetaiotaomicron. Alg, MO and GO can increase the production level of short chain fatty acids (SCFA), but GO generates the highest level of SCFA. Our data suggest that alginate and its derivatives could be degraded by specific bacteria in the human gut, providing the basis for the impacts of alginate and its derivates as special food additives on human health. PMID:26891629

  15. Self-emulsifying excipient platform for improving technological properties of alginate-hydroxypropylcellulose pellets.

    Science.gov (United States)

    Mannina, Paolo; Segale, Lorena; Giovannelli, Lorella; Bonda, Andrea Foglio; Pattarino, Franco

    2016-02-29

    In this work, alginate, alginate-pectin and alginate-hydroxypropylcellulose pellets were produced by ionotropic gelation and characterized. Ibuprofen was selected as model drug; it was suspended in the polymeric solution in crystalline form or dissolved in a self-emulsifying phase and then dispersed into the polymeric solution. The self-emulsifying excipient platform composed of Labrasol (PEG-8 caprylic/capric glycerides) and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS), able to solubilize the drug was used to improve the technological and biopharmaceutical properties of the alginate pellets. The pellets had diameters between 1317 and 2026 μm and a high drug content (>51%). DSC analysis showed the amorphous state of drug in the pellets containing the self-emulsifying phase. All the systems restricted drug release in conditions simulating the gastric environment and made the drug completely available at a pH value typical for the intestine. Only alginate-HPC systems containing the drug solubilized into the self-emulsifying phase showed the ability to partially control the release of ibuprofen at neutral pH. The self-emulsifying excipient platform is a useful tool to improve technological and biopharmaceutical properties of alginate-HPC pellets. PMID:26721727

  16. Floatable, macroporous structured alginate sphere supporting iron nanoparticles used for emergent Cr(VI) spill treatment.

    Science.gov (United States)

    Huang, Jian-Fei; Li, Yong-Tao; Wu, Jin-Hua; Cao, Piao-Yang; Liu, Yong-Lin; Jiang, Gang-Biao

    2016-08-01

    Treatment of hexavalent chromium (Cr(VI)) spill accident is a great challenge due to its high toxicity, sudden and extensiveness. In this study, we designed and fabricated a hierarchical, ordered and macroporous structured alginate sphere to support in-situ synthesized zero-valent iron nanoparticle (the alginate-nZVI sphere). Field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS) images showed well dispersion of nZVI on the composite. This alginate-nZVI sphere exhibited good separability in effective removal of Cr(VI). The result from Cr(VI) removal experiment demonstrated a Cr(VI) removal efficiency of 98.2% at equilibrium time, which can be ascribed to the well dispersion of the nZVI. In addition, the alginate-nZVI sphere was effective in Cr(VI) removal in a wide range of pH from 3.0 to 11.0, by the merit of alginate substrate. Hence, the alginate-nZVI sphere might be a promising agent for an emergent Cr(VI) spill treatment by enhancing the dispersion, stabilization and separation properties of nZVI. PMID:27112857

  17. Osteogenic Differentiation of Human Mesenchymal Stem Cells in Mineralized Alginate Matrices

    Science.gov (United States)

    Westhrin, Marita; Xie, Minli; Olderøy, Magnus Ø.; Sikorski, Pawel

    2015-01-01

    Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering. PMID:25769043

  18. Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices.

    Directory of Open Access Journals (Sweden)

    Marita Westhrin

    Full Text Available Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST and dental matrix protein-1 (DMP1, markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.

  19. Improved delivery of biocontrol Pseudomonas and their antifungal metabolites using alginate polymers.

    Science.gov (United States)

    Russo, A; Moënne-Loccoz, Y; Fedi, S; Higgins, P; Fenton, A; Dowling, D N; O'Regan, M; O'Gara, F

    1996-02-01

    Alginate polymer was evaluated as a carrier for seed inoculation with a genetically modified strain Pseudomonas fluorescens F113LacZY, which protects sugar-beet against Pythium-mediated damping-off. F113LacZY survived in alginate beads at 5 log10 CFU/bead or higher counts for 8 weeks of storage, regardless of the conditions of incubation. In plant inoculation experiments, colonisation of the growing area of the root by F113LacZY, derived from alginate beads placed in the soil next to the seed or from an alginate coating around the seeds, was improved compared with application of just free cells of the strain. F113LacZY trapped in alginate beads was an effective producer of antifungal phloroglucinols as indicated by direct HPLC quantification of phloroglucinols and in vitro inhibition of both the indicator bacterium Bacillus subtilis A1 and the pathogenic fungus Pythium ultimum. Alginate polymer represents a promising carrier for the delivery of biocontrol inoculants for root colonisation and production of antifungal metabolites. PMID:8867631

  20. Performance evaluation of bipolar and tripolar excitations during nozzle-jetting-based alginate microsphere fabrication

    International Nuclear Information System (INIS)

    Microspheres, small spherical (polymeric) particles with or without second phase materials embedded or encapsulated, are important for many biomedical applications such as drug delivery and organ printing. Scale-up fabrication with the ability to precisely control the microsphere size and morphology has always been of great manufacturing interest. The objective of this work is to experimentally study the performance differences of bipolar and tripolar excitation waveforms in using drop-on-demand (DOD)-based single nozzle jetting for alginate microsphere fabrication. The fabrication performance has been evaluated based on the formability of alginate microspheres as a function of materials properties (sodium alginate and calcium chloride concentrations) and operating conditions. The operating conditions for each excitation include voltage rise/fall times, dwell times and excitation voltage amplitudes. Overall, the bipolar excitation is more robust in making spherical, monodispersed alginate microspheres as good microspheres for its wide working range of material properties and operating conditions, especially during the fabrication of highly viscous materials such as the 2% sodium alginate solution. For both bipolar and tripolar excitations, the sodium alginate concentration and the voltage dwell times should be carefully selected to achieve good microsphere formability. (paper)

  1. Influence of amino acids, buffers, and ph on the γ-irradiation-induced degradation of alginates.

    Science.gov (United States)

    Ulset, Ann-Sissel T; Mori, Hideki; Dalheim, Marianne Ø; Hara, Masayuki; Christensen, Bjørn E

    2014-12-01

    Alginate-based biomaterials and medical devices are commonly subjected to γ-irradiation as a means of sterilization, either in the dry state or the gel (hydrated) state. In this process the alginate chains degrade randomly in a dose-dependent manner, altering alginates' material properties. The addition of free radical scavenging amino acids such as histidine and phenylalanine protects the alginate significantly against degradation, as shown by monitoring changes in the molecular weight distributions using SEC-MALLS and determining the pseudo first order rate constants of degradation. Tris buffer (0.5 M), but not acetate, citrate, or phosphate buffers had a similar effect on the degradation rate. Changes in pH itself had only marginal effects on the rate of alginate degradation and on the protective effect of amino acids. Contrary to previous reports, the chemical composition (M/G profile) of the alginates, including homopolymeric mannuronan, was unaltered following irradiation up to 10 kGy. PMID:25412478

  2. Effect of alginate hydrogel containing polyproline-rich peptides on osteoblast differentiation

    International Nuclear Information System (INIS)

    Polyproline-rich synthetic peptides have previously been shown to induce bone formation and mineralization in vitro and to decrease bone resorption in vivo. Alginate hydrogel formulations containing these synthetic peptides (P2, P5, P6) or Emdogain® (EMD) were tested for surface coating of bone implants. In an aqueous environment, the alginate hydrogels disclosed a highly compact structure suitable for cell adhesion and proliferation. Lack of cytotoxicity of the alginate-gel coating containing peptides was tested in MC3T3-E1 cell cultures. In the present study, relative mRNA expression levels of integrin alpha 8 were induced by P5 compared to untreated alginate gel, and osteopontin mRNA levels were increased after 21 days of culture by treatment with synthetic peptides or EMD compared to control. Further, in agreement with previous results when the synthetic peptides were administered in the culture media, osteocalcin mRNA was significantly upregulated after long-term treatment with the formulated synthetic peptides compared to untreated and EMD alginate gel. These results indicate that the alginate gel is a suitable carrier for the delivery of synthetic peptides, and that the formulation is promising as biodegradable and biocompatible coating for bone implants. (paper)

  3. Biological effect of radiation-degraded alginate on flower plants in tissue culture.

    Science.gov (United States)

    Le, Q Luan; Nguyen, Q Hien; Nagasawa, Naotsugu; Kume, Tamikazu; Yoshii, Fumio; Nakanishi, Tomoko M

    2003-12-01

    Alginate with a weight-average molecular mass (Mw) of approx. 9.04 x 10(5) Da was irradiated at 10-200 kGy in 4% (w/v) aqueous solution. The degraded alginate product was used to study its effectiveness as a growth promoter for plants in tissue culture. Alginate irradiated at 75 kGy with an Mw of approx. 1.43 x 10(4) Da had the highest positive effect in the growth of flower plants, namely limonium, lisianthus and chrysanthemum. Treatment of plants with irradiated alginate at concentrations of 30-200 mg/l increased the shoot multiplication rate from 17.5 to 40.5% compared with control. In plantlet culture, 100 mg/l irradiated alginate supplementation enhanced shoot height (9.7-23.2%), root length (9.7-39.4%) and fresh biomass (8.1-19.4%) of chrysanthemum, lisianthus and limonium compared with that of the untreated control. The survival ratios of the transferred flower plantlets treated with irradiated alginate were almost the same as the control value under greenhouse conditions. However, better growth was attained for the treated plantlets. PMID:12901723

  4. Microgravity Separation of Alginate Empty Capsules from Encapsulated Pancreatic Islets Using a Microfluidic System.

    Science.gov (United States)

    Shin, Soojeong; Yoo, Young Je; Hong, Jong Wook

    2015-10-01

    Although microencapsulated pancreatic islets have merits, such as ease of transplantation, viability and functionality improvement, and immune protection in vivo, the co-production of alginate empty capsules during the encapsulation of islets with alginate makes them unusable for biomedical application. In previous research, the removal of empty alginate capsules with high yield was achieved using density-gradient centrifugation. Here, we report advanced microgravity-based separation techniques in a microfluidic format for alginate empty capsules. The optimal separation conditions were mathematically evaluated using Stokes' law and the separation of the encapsulation product was accomplished. A microfluidic chip was designed with two inlets and two outlets at different elevations to mimic the vertical percoll gradient in density-gradient centrifugation. The separation of alginate empty capsules using microgravitational force resulted in effective separation of encapsulated islets from alginate empty capsules with more than 70% efficiency. Moreover, no loss of encapsulated islets was expected because the process is a one-pot separation, unlike the previous method. This type of microgravitational particle separation could be used both for the fractionization of heterogeneous encapsulated cells and to remove empty capsules. PMID:26726432

  5. Novel copper (II) alginate hydrogels and their potential for use as anti-bacterial wound dressings

    International Nuclear Information System (INIS)

    The incorporation of a metal ion, with antimicrobial activity, into an alginate dressing is an attractive approach to minimize infection in a wound. In this work, copper (II) cross-linked alginate hydrogels were successfully prepared using a two-step cross-linking procedure. In the first step, solid alginate films were prepared using a solvent-casting method from soft gels of alginate solutions that had been lightly cross-linked using a copper (II) (Cu2+) sulfate solution. In the second step, the films were further cross-linked in a corresponding Cu2+ sulfate solution using a dipping method to further improve their dimensional stability. Alginate solution (at 2%w/v) and Cu2+ sulfate solution (at 2%w/v) in acetate buffer at a low pH provided soft films with excellent swelling behavior. An increase in either Cu2+ ion concentration or cross-linking time led to hydrogels with more densely-cross-linked networks that limited water absorption. The hydrogels clearly showed antibacterial activity against Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis and Streptococcus pyogenes, which was proportional to the Cu2+ ion concentration. Blood coagulation studies showed that the tested copper (II) cross-linked alginate hydrogels had a tendency to coagulate fibrin, and possibly had an effect on pro-thrombotic coagulation and platelet activation. Conclusively, the prepared films are likely candidates as antibacterial wound dressings. (paper)

  6. Evaluation of gene expression and alginate production in response to oxygen transfer in continuous culture of Azotobacter vinelandii.

    Directory of Open Access Journals (Sweden)

    Alvaro Díaz-Barrera

    Full Text Available Alginates are polysaccharides used as food additives and encapsulation agents in biotechnology, and their functional properties depend on its molecular weight. In this study, different steady-states in continuous cultures of A. vinelandii were established to determine the effect of the dilution rate (D and the agitation rate on alginate production and expression of genes involved in alginate polymerization and depolymerization. Both, the agitation and dilution rates, determined the partitioning of the carbon utilization from sucrose into alginate and CO2 under oxygen-limiting conditions. A low D (0.07 h(-1 and 500 rpm resulted in the highest carbon utilization into alginate (25%. Quantitative real-time polymerase chain reaction was used to determine the transcription level of six genes involved in alginate polymerization and depolymerization. In chemostat cultures at 0.07 h(-1, the gene expression was affected by changes in the agitation rate. By increasing the agitation rate from 400 to 600 rpm, the algE7 gene expression decreased tenfold, whereas alyA1, algL and alyA2 gene expression increased between 1.5 and 2.8 times under similar conditions evaluated. Chemostat at 0.07 h(-1 showed a highest alginate molecular weight (580 kDa at 500 rpm whereas similar molecular weights (480 kDa were obtained at 400 and 600 rpm. The highest molecular weight was not explained by changes in the expression of alg8 and alg44 (genes involved in alginate polymerization. Nonetheless, a different expression pattern observed for lyases could explain the highest alginate molecular weight obtained. Overall, the results suggest that the control of alginate molecular weight in A. vinelandii cells growing in continuous mode is determined by a balance between the gene expression of intracellular and extracellular lyases in response to oxygen availability. These findings better our understanding of the biosynthesis of bacterial alginate and help us progress toward obtain

  7. Encapsulating Non-Human Primate Multipotent Stromal Cells in Alginate via High Voltage for Cell-Based Therapies and Cryopreservation

    OpenAIRE

    Gryshkov, Oleksandr; Pogozhykh, Denys; Hofmann, Nicola; Pogozhykh, Olena; Mueller, Thomas; Glasmacher, Birgit

    2014-01-01

    Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedu...

  8. Molecular and bioengineering strategies to improve alginate and polydydroxyalkanoate production by Azotobacter vinelandii

    Directory of Open Access Journals (Sweden)

    Espín Guadalupe

    2007-02-01

    Full Text Available Abstract Several aspects of alginate and PHB synthesis in Azotobacter vinelandii at a molecular level have been elucidated in articles published during the last ten years. It is now clear that alginate and PHB synthesis are under a very complex genetic control. Genetic modification of A. vinelandii has produced a number of very interesting mutants which have particular traits for alginate production. One of these mutants has been shown to produce the alginate with the highest mean molecular mass so far reported. Recent work has also shed light on the factors determining molecular mass distribution; the most important of these being identified as; dissolved oxygen tension and specific growth rate. The use of specific mutants has been very useful for the correct analysis and interpretation of the factors affecting polymerization. Recent scale-up/down work on alginate production has shown that oxygen limitation is crucial for producing alginate of high molecular mass, a condition which is optimized in shake flasks and which can now be reproduced in stirred fermenters. It is clear that the phenotypes of mutants grown on plates are not necessarily reproducible when the strains are tested in lab or bench scale fermenters. In the case of PHB, A. vinelandii has shown itself able to produce relatively large amounts of this polymer of high molecular weight on cheap substrates, even allowing for simple extraction processes. The development of fermentation strategies has also shown promising results in terms of improving productivity. The understanding of the regulatory mechanisms involved in the control of PHB synthesis, and of its metabolic relationships, has increased considerably, making way for new potential strategies for the further improvement of PHB production. Overall, the use of a multidisciplinary approach, integrating molecular and bioengineering aspects is a necessity for optimizing alginate and PHB production in A. vinelandii.

  9. Preparation, Properties and Mechanism of Inhomogeneous Calcium Alginate Ion Cross-linking Gel Microspheres

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Inhomogeneous calcium alginate ion cross-linking gel microspheres, a novel ion absorbent, were prepared by dropping a sodium alginate solution to a calcium chloride solution via an electronic droplet generator. Calcium alginate microspheres have uniform particle sizes, a smooth surface and a microporous structure. The electrode probe reveals the inhomogeneous distribution of calcium ions with the highest concentration on the surface, and the lowest concentration in the cores of the spheres. As a novel ion adsorbent, calcium alginate gel microspheres have a lower limiting adsorption mass concentration, a higher enrichment capacity and a higher adsorption capacity for Pb2+ than usual ion exchange resins. The highest percentage of the adsorption is 99.79%. The limiting adsorption mass concentration is 0.0426 mg/L. The adsorption capacity for Pb2+ is 644 mg/g. Calcium alginate gel microspheres have a much faster ion exchange velocity than D418 chelating resin and D113 polyacrylate resin. The moving boundary model was employed to interpret the ion exchange kinetics process, which indicates that the ion exchange process is controlled by intraparticle diffusion of adsorbable ions. So the formation of inhomogeneous gel microspheres reduces the diffusion distance of adsorbable ions within the spheres and enhances the ion exchange velocity. Alginate has a higher selectivity for Pb2+ than for Ca2+ and the selectivity coefficient KPbCa is 316. As an ion cross-linking gel, calcium alginate inhomogeneous microspheres can effectively adsorb heavy metal Pb2+ at a higher selectivity and a higher adsorption velocity. It is a novel and good ion adsorbent.

  10. Metal selectivity of Sargassum spp. and their alginates in relation to their alpha-L-guluronic acid content and conformation.

    Science.gov (United States)

    Davis, Thomas A; Llanes, Francisco; Volesky, Bohumil; Mucci, Alfonso

    2003-01-15

    The discovery of a consistent and unusual enrichment in homopolymeric alpha-L-guluronic acid G-blocks in alginates extracted from a suite of Sargassum brown algae is described in this study. 1H NMR spectroscopy was used to characterize these alginates which display homopolymeric guluronic acid block (G-block) frequency values (F(GG)) between 0.37 and 0.81. The presence of these G-blocks results in an enhanced selectivity for cadmium or calcium relative to monovalent ions such as sodium and the proton as well as smaller divalent ions such as magnesium. Results of competitive exchange experiments for the Cd-Ca-alginate system yield selectivity coefficient, K*(Cd)Ca, values between 0.43 +/- 0.10 and 1.32 +/- 0.02 for a range in F(GG) of 0.23 to 0.81. In contrast to the Cd-Ca-alginate system, the Mg-Ca-alginate and Mg-Cd-alginate systems yielded maximum values of K*(Mg)Ca (18.0 +/- 1.4) and K*(Mg)Cd (16.0 +/- 0.9) for the alginates extracted from Sargassum fluitans (F(GG) = 0.81; Cuba) and Sargassum thunbergii (F(GG) = 0.75; Korea), respectively. Selectivity studies with mixed-metal pair alginate systems highlight the importance of the specific macromolecular conformation of the alginate polymer in determining metal binding behavior in multiple-metal systems. Furthermore, they demonstrate the importance of the conformation of the alginate as it occurs within the tissue of Sargassum in determining the metal binding behavior of this algal biosorbent. The unique composition of the alginates present in species of Sargassum may represent a distinct advantage over other brown algal species when considering their implementation for the strategic removal of toxic heavy metals from contaminated and industrial wastewaters. PMID:12564896

  11. Regulation of pH attenuates toxicity of a byproduct produced by an ethanologenic strain of Sphingomonas sp. A1 during ethanol fermentation from alginate

    OpenAIRE

    Fujii, Mari; Yoshida, Shiori; Murata, Kousaku; Kawai, Shigeyuki

    2014-01-01

    Marine macroalgae is a promising carbon source that contains alginate and mannitol as major carbohydrates. A bioengineered ethanologenic strain of the bacterium Sphingomonas sp. A1 can produce ethanol from alginate, but not mannitol, whereas the yeast Saccharomyces paradoxus NBRC 0259–3 can produce ethanol from mannitol, but not alginate. Thus, one practical approach for converting both alginate and mannitol into ethanol would involve two-step fermentation, in which the ethanologenic bacteriu...

  12. Novel crosslinked alginate/hyaluronic acid hydrogels for nerve tissue engineering

    Science.gov (United States)

    Wang, Min-Dan; Zhai, Peng; Schreyer, David J.; Zheng, Ruo-Shi; Sun, Xiao-Dan; Cui, Fu-Zhai; Chen, Xiong-Biao

    2013-09-01

    Artificial tissue engineering scaffolds can potentially provide support and guidance for the regrowth of severed axons following nerve injury. In this study, a hybrid biomaterial composed of alginate and hyaluronic acid (HA) was synthesized and characterized in terms of its suitability for covalent modification, biocompatibility for living Schwann cells and feasibility to construct three dimensional (3D) scaffolds. Carbodiimide mediated amide formation for the purpose of covalent crosslinking of the HA was carried out in the presence of calciumions that ionically crosslink alginate. Amide formation was found to be dependent on the concentrations of carbodiimide and calcium chloride. The double-crosslinked composite hydrogels display biocompatibility that is comparable to simple HA hydrogels, allowing for Schwann cell survival and growth. No significant difference was found between composite hydrogels made from different ratios of alginate and HA. A 3D BioPlotter™ rapid prototyping system was used to fabricate 3D scaffolds. The result indicated that combining HA with alginate facilitated the fabrication process and that 3D scaffolds with porous inner structure can be fabricated from the composite hydrogels, but not from HA alone. This information provides a basis for continuing in vitro and in vivo tests of the suitability of alginate/HA hydrogel as a biomaterial to create living cell scaffolds to support nerve regeneration.

  13. Biosorption of radiostrontium by alginate beads. Application of isotherm models and thermodynamic studies

    International Nuclear Information System (INIS)

    Radioactive strontium is one of the major radioactive contaminant and its contamination is a very serious concern. Therefore, there is a need for economic, effective, non-toxic, readily available and abundant adsorbent or biosorbent to remove strontium from solutions. In this study, biosorption of 85Sr as a surrogate for 90Sr onto alginate beads was investigated in a batch system. Alginate beads were prepared from Na-alginate via cross-linking with divalent calcium ions according to the egg box model. The effect of several parameters such as pH, initial strontium concentration, contact time, dosage of alginate beads and temperature were investigated. In order to optimize the design of biosorption system for the removal of strontium, it is important to establish the most appropriate correlation for equilibrium curves. The experimental isotherm data were described by 6 different biosorption isotherm models, namely Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Flory-Huggins and Brunauer, Emmer and Teller, with constants obtained from linear and non-linear regression methods. The thermodynamic parameters (ΔHdeg, ΔSdeg and ΔGdeg) for strontium biosorption were also determined. The results indicate that these alginate beads have a good potential for the biosorption of strontium from solutions. (author)

  14. Adsorption of ochratoxin A from grape juice by yeast cells immobilised in calcium alginate beads.

    Science.gov (United States)

    Farbo, Maria Grazia; Urgeghe, Pietro Paolo; Fiori, Stefano; Marceddu, Salvatore; Jaoua, Samir; Migheli, Quirico

    2016-01-18

    Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72-120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. PMID:26485316

  15. Survivability of probiotics encapsulated in alginate gel microbeads using a novel impinging aerosols method.

    Science.gov (United States)

    Sohail, Asma; Turner, Mark S; Coombes, Allan; Bostrom, Thor; Bhandari, Bhesh

    2011-01-31

    Encapsulation of probiotic bacteria in cross-linked alginate beads is of major interest for improving the survivability in harsh acid and bile environment and also in food matrices. Alginate micro beads (10-40 μm) containing the probiotics Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM were produced by a novel technique based on dual aerosols of alginate solution and CaCl(2) cross linking solution. Extruded macro beads (approximately 2mm diameter) produced by the conventional method and micro beads produced by novel aerosols technique offered comparable protection to L. rhamnosus in high acid and bile environment. Chitosan coating of micro beads resulted in a significant increase in survival time of L. rhamnosus from 40 to 120 min in acid condition and the reduction in cell numbers was confined to 0.94 log over this time. Alginate macro beads are more effective than micro beads in protecting L. acidophilus against high acid and bile. Chitosan coating of micro beads resulted in similar protection to L. acidophilus in macro beads in acid and extended the survival time from 90 to at least 120 min. Viability of this organism in micro beads was 3.5 log after 120 min. The continuous processing capability and scale-up potential of the dual aerosol technique offers potential for an efficient encapsulation of probiotics in very small alginate micro beads below sensorial detection limits while still being able to confer effective protection in acid and bile environment. PMID:21276627

  16. Characterization of calcium alginate beads of 5-fluorouracil for colon delivery

    Directory of Open Access Journals (Sweden)

    Patel Hetal

    2008-01-01

    Full Text Available A multiparticulate system combining pH-sensitive property and specific biodegradability for colon targeted delivery of 5-fluorouracil (5-FU was examined. The purpose of this study was to prepare and evaluate the colon-specific alginate beads of 5-FU for the treatment of colon cancer. Calcium alginate beads were prepared by extruding 5-FU loaded alginate solution to calcium chloride solution, and gelled spheres were formed instantaneously by ionotropic gelation reaction using different ratios of FU and alginate, alginate and calcium chloride, stirring speeds (500-1500 rpm, and reaction time. The core beads were coated with Eudragit S-100 to prevent drug release in the stomach and provide controlled dissolution of enteric coat in the small intestine and maximum drug release in the colon. Morphology and surface characteristics of the formulation were determined by scanning electron microscopy. In vitro drug release studies were performed in conditions simulating stomach to colon transit. No significant release was observed at acidic pH, however, when it reached the pH where Eudragit S-100 starts to dissolve, drug release was observed. Also, release of drug was found to be higher in presence of rat caecal content.

  17. Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.

    Science.gov (United States)

    Iglesias, O; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix. PMID:22851224

  18. Development of Alginate Microspheres Containing Chuanxiong for Oral Administration to Adult Zebrafish

    Directory of Open Access Journals (Sweden)

    Li-Jen Lin

    2016-01-01

    Full Text Available Oral administration of Traditional Chinese Medicine (TCM by patients is the common way to treat health problems. Zebrafish emerges as an excellent animal model for the pharmacology investigation. However, the oral delivery system of TCM in zebrafish has not been established so far. This issue was addressed by development of alginate microparticles for oral delivery of chuanxiong, a TCM that displays antifibrotic and antiproliferative effects on hepatocytes. The delivery microparticles were prepared from gelification of alginate containing various levels of chuanxiong. The chuanxiong-encapsulated alginate microparticles were characterized for their solubility, structure, encapsulation efficiency, the cargo release profile, and digestion in gastrointestinal tract of zebrafish. Encapsulation of chuanxiong resulted in more compact structure and the smaller size of microparticles. The release rate of chuanxiong increased for alginate microparticles carrying more chuanxiong in simulated intestinal fluid. This remarkable feature ensures the controlled release of encapsulated cargos in the gastrointestinal tract of zebrafish. Moreover, chuanxiong-loaded alginate microparticles were moved to the end of gastrointestinal tract after oral administration for 6 hr and excreted from the body after 16 hr. Therefore, our developed method for oral administration of TCM in zebrafish is useful for easy and rapid evaluation of the drug effect on disease.

  19. Development of Alginate Microspheres Containing Chuanxiong for Oral Administration to Adult Zebrafish.

    Science.gov (United States)

    Lin, Li-Jen; Chiang, Chung-Jen; Chao, Yun-Peng; Wang, Shulhn-Der; Chiou, Yu-Ting; Wang, Han-Yu; Kao, Shung-Te

    2016-01-01

    Oral administration of Traditional Chinese Medicine (TCM) by patients is the common way to treat health problems. Zebrafish emerges as an excellent animal model for the pharmacology investigation. However, the oral delivery system of TCM in zebrafish has not been established so far. This issue was addressed by development of alginate microparticles for oral delivery of chuanxiong, a TCM that displays antifibrotic and antiproliferative effects on hepatocytes. The delivery microparticles were prepared from gelification of alginate containing various levels of chuanxiong. The chuanxiong-encapsulated alginate microparticles were characterized for their solubility, structure, encapsulation efficiency, the cargo release profile, and digestion in gastrointestinal tract of zebrafish. Encapsulation of chuanxiong resulted in more compact structure and the smaller size of microparticles. The release rate of chuanxiong increased for alginate microparticles carrying more chuanxiong in simulated intestinal fluid. This remarkable feature ensures the controlled release of encapsulated cargos in the gastrointestinal tract of zebrafish. Moreover, chuanxiong-loaded alginate microparticles were moved to the end of gastrointestinal tract after oral administration for 6 hr and excreted from the body after 16 hr. Therefore, our developed method for oral administration of TCM in zebrafish is useful for easy and rapid evaluation of the drug effect on disease. PMID:27403425

  20. Improved Water Barrier Properties of Calcium Alginate Capsules Modified by Silicone Oil

    Directory of Open Access Journals (Sweden)

    Brian G. Zukas

    2016-04-01

    Full Text Available Calcium alginate films generally offer poor diffusion resistance to water. In this study, we present a technique for encapsulating aqueous drops in a modified calcium alginate membrane made from an emulsion of silicone oil and aqueous alginate solution and explore its effect on the loss of water from the capsule cores. The capsule membrane storage modulus increases as the initial concentration of oil in the emulsion is increased. The water barrier properties of the fabricated capsules were determined by observing the mass loss of capsules in a controlled environment. It was found that capsules made with emulsions containing 50 wt% silicone oil were robust while taking at least twice the time to dry completely as compared to capsules made from only an aqueous alginate solution. The size of the oil droplets in the emulsion also has an effect on the water barrier properties of the fabricated capsules. This study demonstrates a facile method of producing aqueous core alginate capsules with a modified membrane that improves the diffusion resistance to water and can have a wide range of applications.

  1. Differentiation of Wharton's jelly mesenchymal stem cells into neurons in alginate scaffold

    Science.gov (United States)

    Hosseini, Seyed Mojtaba; Vasaghi, Attiyeh; Nakhlparvar, Newsha; Roshanravan, Reza; Talaei-khozani, Tahereh; Razi, Zahra

    2015-01-01

    Alginate scaffold has been considered as an appropriate biomaterial for promoting the differentiation of embryonic stem cells toward neuronal cell lineage. We hypothesized that alginate scaffold is suitable for culturing Wharton's jelly mesenchymal stem cells (WJMSCs) and can promote the differentiation of WJMSCs into neuron-like cells. In this study, we cultured WJMSCs in a three-dimensional scaffold fabricated by 0.25% alginate and 50 mM CaCl2 in the presence of neurogenic medium containing 10 μM retinoic acid and 20 ng/mL basic fibroblast growth factor. These cells were also cultured in conventional two-dimensional culture condition in the presence of neurogenic medium as controls. After 10 days, immunofluorescence staining was performed for detecting β-tubulin (marker for WJMSCs-differentiated neuron) and CD271 (motor neuron marker). β-Tubulin and CD271 expression levels were significantly greater in the WJMSCs cultured in the three-dimensional alginate scaffold than in the conventional two-dimensional culture condition. These findings suggest that three-dimensional alginate scaffold cell culture system can induce neuronal differentiation of WJMSCs effectively. PMID:26487861

  2. Effects of alginate edible coating on quality and antioxidant properties in sweet cherry during postharvest storage

    Directory of Open Access Journals (Sweden)

    V. Chiabrando

    2015-06-01

    Full Text Available Two sweet cherry (Prunus avium L. cultivars (“Big Lory” and “Grace Star”, were treated with 1%, 3% and 5% sodium alginate as an edible coating before storage. Analytical determinations were made after 7, 14 and 21 days of storage at 4°C. Cherries were analyzed for the following quality parameters: firmness, weight loss, titratable acidity, soluble solid content, external color, anthocyanin content, phenolic content and total antioxidant capacity. Alginate treatment at 3% delayed changes in most of the ripening parameters, weight and acidity losses, softening and color changes. However, the soluble solids content was not affected by the alginate fruit coating. In terms of the antioxidant properties, no significant results were obtained with the use of the alginate coating. The results of this study suggest that alginate treatments at 1% and 3% could be used as natural postharvest treatments in cherry cultivars with the aim of delaying the postharvest ripening process and maintaining fruit quality.

  3. Alginate gelation-induced cell death during laser-assisted cell printing

    International Nuclear Information System (INIS)

    Modified laser-induced forward transfer has emerged as a promising bioprinting technique. Depending on the operating conditions and cell properties, laser cell printing may cause cell injury and even death, which should be carefully elucidated for it to be a viable technology. This study has investigated the effects of alginate gelation, gelation time, alginate concentration, and laser fluence on the post-transfer cell viability of NIH 3T3 fibroblasts. Sodium alginate and calcium chloride are used as the gel precursor and gel reactant solution to form cell-laden alginate microspheres. It is found that the effects of gelation depend on the duration of gelation. Two-minute gelation is observed to increase the cell viability after 24 h incubation, mainly due to the protective cushion effect of the forming gel membrane during droplet landing. Despite the cushion effect from 10 min gelation, it is observed that the cell viability decreases after 24 h incubation because of the forming thick gel membrane that reduces nutrient and oxygen diffusion from the culture medium. In addition, the cell viability after 24 h incubation decreases as the laser fluence or alginate concentration increases. (paper)

  4. A simple approach for morphology tailoring of alginate particles by manipulation ionic nature of polyurethanes.

    Science.gov (United States)

    Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

    2014-05-01

    A number of different ionic aqueous polyurethane dispersions (PUDs) were synthesized based on NCO-terminated prepolymers. Two different anionic and cationic polyurethane samples were synthesized using dimethylol propionic acid and N-methyldiethanolamine emulsifiers, respectively. Then, proper amounts of PUDs and sodium alginate were mixed to obtain a number of aqueous polyurethane dispersions-sodium alginate (PUD/SA) elastomers. The chemical structure, thermal, morphological, thermo-mechanical and mechanical properties, and hydrophilicity content of the prepared samples were studied by FTIR, EDX, DSC, TGA, SEM, DMTA, tensile testing and contact angle techniques. The cationic polyurethanes and their blends with sodium alginate showed excellent miscibility and highly stretchable properties, while the samples containing anionic polyurethanes and alginate illustrated a poor compatibility and no significant miscibility. The morphology of alginate particles shifted from nanoparticles to microparticles by changing the nature of PUDs from cationic to anionic types. The final cationic elastomers not only showed better mechanical properties but also were formulated easier than anionic samples. PMID:24560945

  5. Development of Alginate Microspheres Containing Chuanxiong for Oral Administration to Adult Zebrafish

    Science.gov (United States)

    Lin, Li-Jen; Chiang, Chung-Jen; Chao, Yun-Peng; Wang, Shulhn-Der; Chiou, Yu-Ting; Wang, Han-Yu; Kao, Shung-Te

    2016-01-01

    Oral administration of Traditional Chinese Medicine (TCM) by patients is the common way to treat health problems. Zebrafish emerges as an excellent animal model for the pharmacology investigation. However, the oral delivery system of TCM in zebrafish has not been established so far. This issue was addressed by development of alginate microparticles for oral delivery of chuanxiong, a TCM that displays antifibrotic and antiproliferative effects on hepatocytes. The delivery microparticles were prepared from gelification of alginate containing various levels of chuanxiong. The chuanxiong-encapsulated alginate microparticles were characterized for their solubility, structure, encapsulation efficiency, the cargo release profile, and digestion in gastrointestinal tract of zebrafish. Encapsulation of chuanxiong resulted in more compact structure and the smaller size of microparticles. The release rate of chuanxiong increased for alginate microparticles carrying more chuanxiong in simulated intestinal fluid. This remarkable feature ensures the controlled release of encapsulated cargos in the gastrointestinal tract of zebrafish. Moreover, chuanxiong-loaded alginate microparticles were moved to the end of gastrointestinal tract after oral administration for 6 hr and excreted from the body after 16 hr. Therefore, our developed method for oral administration of TCM in zebrafish is useful for easy and rapid evaluation of the drug effect on disease.

  6. Characterization of slow-gelling alginate hydrogels for intervertebral disc tissue-engineering applications.

    Science.gov (United States)

    Growney Kalaf, Emily A; Flores, Reynaldo; Bledsoe, J Gary; Sell, Scott A

    2016-06-01

    Reversal of intervertebral disc degeneration can have a potentially monumental effect on spinal health. As such, the goal of this research is to create an injectable, cellularized alginate-based nucleus pulposus that will restore disc function; with the primary goal of creating an alginate gel with tailorable rates of gelation to improve functionality over standard CaCl2 crosslinking techniques. Gelation characteristics of 1% sodium alginate were analyzed over various molar concentrations of a 1:2 ratio of CaCO3:glucono-δ-lactone (GDL), with 10% CaCl2 as the control crosslinker. Alginate construct characterization for all concentrations was performed via ultimate and cyclic compressive testing over a 28day degradation period in PBS. Dehydration, swell testing, and albumin release kinetics were determined, and cytotoxicity and cell homogeneity tests showed promise for cellularization strategies. Overall, the 30 and 60mM GDL alginate concentrations presented the most viable option for use in further studies, with a gelation time between 10 and 30min, low hysteresis over control, low percent change in thickness and weight under both PBS degradation and swelling conditions, and stable mechanical properties over 28days in vitro. PMID:27040212

  7. Copper Alginate-Cotton Cellulose (CACC Fibers with Excellent Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Navin Chand, Ph.D.

    2009-09-01

    Full Text Available The present work describes synthesis of copper alginate-cotton cellulose (CACC composite fibers and detailed investigation of antimicrobial action against the model bacteria E.coli. The CACC fibers were prepared by immersing cotton fibers in aqueous solution of sodium alginate, followed by ionic crosslinking of alginate chains within the cotton cellulose fibers with Cu(II ions to yield CACC composite fibers. The resulting CACC fibers were investigated for their biocidal action against E.coli, by using zone inhibition and colonies counting method. Finally, CACC fibers were reduced with sodium borohydride to yield copper nanoparticles- loaded composite fibers and investigated for biocidal action. It was found that CACC fibers possessed both, the fair mechanical strength and antibacterial action. The extent of biocidal action was found to depend upon the amount of Cu(II loaded and concentration of alginate into cotton- cellulose fibers. The fibers showed higher Cu(II release in physiological fluid as compared to distilled water. Copper alginate-cotton cellulose (CACC fibers show fair mechanical strength and release copper ions in the presence of physiological fluid and protein solution. These fibers have great potential to be used as dressing materials.

  8. Silk sericin loaded alginate nanoparticles: Preparation and anti-inflammatory efficacy.

    Science.gov (United States)

    Khampieng, Thitikan; Aramwit, Pornanong; Supaphol, Pitt

    2015-09-01

    In this study, silk sericin loaded alginate nanoparticles were prepared by the emulsification method followed by internal crosslinking. The effects of various silk sericin loading concentration on particle size, shape, thermal properties, and release characteristics were investigated. The initial silk sericin loadings of 20, 40, and 80% w/w to polymer were incorporated into these alginate nanoparticles. SEM images showed a spherical shape and small particles of about 71.30-89.50 nm. TGA analysis showed that thermal stability slightly increased with increasing silk sericin loadings. FTIR analysis suggested interactions between alginate and silk sericin in the nanoparticles. The release study was performed in acetate buffer at normal skin conditions (pH 5.5; 32 °C). The release profiles of silk sericin exhibited initial rapid release, consequently with sustained release. These silk sericin loaded alginate nanoparticles were further incorporated into topical hydrogel and their anti-inflammatory properties were studied using carrageenan-induced paw edema assay. The current study confirms the hypothesis that the application of silk sericin loaded alginate nanoparticle gel can inhibit inflammation induced by carrageenan. PMID:26188300

  9. Design and performance of a sericin-alginate interpenetrating network hydrogel for cell and drug delivery

    Science.gov (United States)

    Zhang, Yeshun; Liu, Jia; Huang, Lei; Wang, Zheng; Wang, Lin

    2015-07-01

    Although alginate hydrogels have been extensively studied for tissue engineering applications, their utilization is limited by poor mechanical strength, rapid drug release, and a lack of cell adhesive ability. Aiming to improve these properties, we employ the interpenetrating hydrogel design rationale. Using alginate and sericin (a natural protein with many unique properties and a major component of silkworm silk), we develop an interpenetrating polymer network (IPN) hydrogel comprising interwoven sericin and alginate double networks. By adjusting the sericin-to-alginate ratios, IPNs’ mechanical strength can be adjusted to meet stiffness requirements for various tissue repairs. The IPNs with high sericin content show increased stability during degradation, avoiding pure alginate’s early collapse. These IPNs have high swelling ratios, benefiting various applications such as drug delivery. The IPNs sustain controlled drug release with the adjustable rates. Furthermore, these IPNs are adhesive to cells, supporting cell proliferation, long-term survival and migration. Notably, the IPNs inherit sericin’s photoluminescent property, enabling bioimaging in vivo. Together, our study indicates that the sericin-alginate IPN hydrogels may serve as a versatile platform for delivering cells and drugs, and suggests that sericin may be a building block broadly applicable for generating IPN networks with other biomaterials for diverse tissue engineering applications.

  10. Synthesis of Thermal Polymerizable Alginate-GMA Hydrogel for Cell Encapsulation

    Directory of Open Access Journals (Sweden)

    Xiaokun Wang

    2015-01-01

    Full Text Available Alginate is a negative ionic polysaccharide that is found abundantly in nature. Calcium is usually used as a cross-linker for alginate. However, calcium cross-linked alginate is used only for in vitro culture. In the present work, alginate was modified with glycidyl methacrylate (GMA to produce a thermal polymerizable alginate-GMA (AA-GMA macromonomer. The molecular structure and methacrylation (%DM of the macromonomer were determined by 1H NMR. After mixing with the correct amount of initiator, the AA-GMA aqueous solution can be polymerized at physiological temperature. The AA-GMA hydrogels exhibited a three-dimensional porous structure with an average pore size ranging from 50 to 200 μm, directly depending on the macromonomer concentration. Biocompatibility of the AA-GMA hydrogel was determined by in vivo muscle injection and cell encapsulation. Muscle injection in vivo showed that the AA-GMA solution mixed with initiator could form a hydrogel in situ and had a mild inflammatory effect. Human umbilical vein endothelial cells (HUVECs were encapsulated in the AA-GMA hydrogels in situ at 37°C. Cell viability and proliferation were unaffected by macromonomer concentrations, which suggests that AA-GMA has a potential application in the field of tissue engineering, especially for myocardial repair.

  11. Effects of cell entrapment in Ca-alginate on the metabolism of yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae cells grown in suspension have been immobilized in calcium-alginate beads. Fermentation rates and intracellular composition have been determined under nongrowing conditions in these Ca-alginate entrapped cells and for identical cells in suspension. Glucose uptake and ethanol and glycerol production are approximately two times faster in immobilized cells than in suspended cells. Intermediate metabolite levels such as fructose-1,6-diphosphate, glucose-6-phosphate and 3-phosphoglycerate have been determined by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy under glucose fermenting conditions. Carbon-13 NMR shows an increase in polysaccharide production in immobilized cells. S. cerevisiae cells grown within a Ca-alginate matrix have a specific growth rate 40% lower than the growth rate of similar cells cultivated in suspension. Alginate-grown cells have been used to compare glucose fermentation under nongrowing conditions in suspended and Ca-entrapped cells. Fermentation rate is higher in immobilized cells than in suspended cells. The observed differences in intracellular components between suspended and immobilized cells are qualitatively similar to the differences observed for cells grown in suspension. Ethanol production rate is 2.7 times faster in immobilized alginate-grown cells than in suspended suspension-grown cells

  12. Polymeric microcapsules poduction from sodium alginic acid for cell therapy

    Directory of Open Access Journals (Sweden)

    Ana Carolina Vale Campos Lisboa

    2007-12-01

    Full Text Available Development of polymeric materials has been increasingly emphasized in Biomedicine. Here, we evaluate the use of microcapsules made of Biodritin®, a biocompatible polymer compound which contains sodium alginic acid, a natural polymer extracted from algae, and Cis-Chondroitin sulfate, a glycosaminoglycan from the extracellular matrix. Gelation of this polymer into microcapsules is achieved by dropping the compound into BaCl2 or CaCl2 gelling solutions. A functional microcapsule is dependent on its permeability, mechanical stability, immunoisolation capacity and biocompatibility. The mechanical stability of Biodritin-barium and Biodritin-calcium microcapsules was investigated after rotational stress upon in vitro culture and in vivo implantation. Viability studies of encapsulated cells were also performed to assess other functional parameters of the microcapsules. When subject to rotational stress, Biodritin-barium microcapsules exhibited breaks, whereas the Biodritin-calcium microcapsules did not. Both kinds of Biodritin® microcapsules proved to be mechanically resistant in in vitro and in vivo studies. However, the Biodritin-calcium material was found to be more elastic while the Biodritin-barium microcapsules displayed a more plastic behavior. These properties seem to be determinant for viability of the encapsulated cell’s, since the Biodritin-calcium microcapsules presented more viable cells than the Biodritin-barium microcapsules.

  13. Development of edible films and coatings from alginates and carrageenans.

    Science.gov (United States)

    Tavassoli-Kafrani, Elham; Shekarchizadeh, Hajar; Masoudpour-Behabadi, Mahdieh

    2016-02-10

    The use of renewable resources, which can reduce waste disposal problems, is being explored to produce biopolymer films and coatings. Renewability, degradability, and edibility make such films particularly suitable for food and nonfood packaging applications. Edible films and coatings play an important role in the quality, safety, transportation, storage, and display of a wide range of fresh and processed foods. They can diminish main alteration by avoiding moisture losses and decreasing adverse chemical reaction rates. Also, they can prevent spoilage and microbial contamination of foods. Additionally, nanomaterials and food additives, such as flavors, antimicrobials, antioxidants, and colors, can be incorporated into edible films and coatings in order to extend their applications. Water-soluble hydrocolloids like polysaccharides usually impart better mechanical properties to edible films and coatings than do hydrophobic substances. They also are excellent barriers to oxygen and carbon dioxide. Recently, there has been much attention on carrageenan and alginate as sources of film-forming materials. Thus, this review highlights production and characteristics of these films. PMID:26686140

  14. Governing Principles of Alginate Microparticle Synthesis with Centrifugal Forces.

    Science.gov (United States)

    Eral, Huseyin Burak; Safai, Eric R; Keshavarz, Bavand; Kim, Jae Jung; Lee, Jisoek; Doyle, P S

    2016-07-19

    A controlled synthesis of polymeric particles is becoming increasingly important because of emerging applications ranging from medical diagnostics to self-assembly. Centrifugal synthesis of hydrogel microparticles is a promising method, combining rapid particle synthesis and the ease of manufacturing with readily available laboratory equipment. This method utilizes centrifugal forces to extrude an aqueous polymer solution, sodium alginate (NaALG) through a nozzle. The extruded solution forms droplets that quickly cross-link upon contact with aqueous calcium chloride (CaCl2) solution to form hydrogel particles. The size distribution of hydrogel particles is dictated by the pinch-off behavior of the extruded solution through a balance of inertial, viscous, and surface tension stresses. We identify the parameters dictating the particle size and provide a numerical correlation predicting the average particle size. Furthermore, we create a phase map identifying different pinch-off regimes (dripping without satellites, dripping with satellites, and jetting), explaining the corresponding particle size distributions, and present scaling arguments predicting the transition between regimes. By shedding light on the underlying physics, this study enables the rational design and operation of particle synthesis by centrifugal forces. PMID:27311392

  15. Simulation of Enzyme Catalysis in Calcium Alginate Beads

    Directory of Open Access Journals (Sweden)

    Ameel M. R. Al-Mayah

    2012-01-01

    Full Text Available A general mathematical model for a fixed bed immobilized enzyme reactor was developed to simulate the process of diffusion and reaction inside the biocatalyst particle. The modeling and simulation of starch hydrolysis using immobilized α-amylase were used as a model for this study. Corn starch hydrolysis was carried out at a constant pH of 5.5 and temperature of . The substrate flow rate was ranging from 0.2 to 5.0 mL/min, substrate initial concentrations 1 to 100 g/L. α-amylase was immobilized on to calcium alginate hydrogel beads of 2 mm average diameter. In this work Michaelis-Menten kinetics have been considered. The effect of substrate flow rate (i.e., residence time and initial concentration on intraparticle diffusion have been taken into consideration. The performance of the system is found to be affected by the substrate flow rate and initial concentrations. The reaction is controlled by the reaction rate. The model equation was a nonlinear second order differential equation simulated based on the experimental data for steady state condition. The simulation was achieved numerically using FINITE ELEMENTS in MATLAB software package. The simulated results give satisfactory results for substrate and product concentration profiles within the biocatalyst bead.

  16. Elucidation of aqueous interactions between fish gelatin and sodium alginate.

    Science.gov (United States)

    Razzak, Md Abdur; Kim, Moojoong; Chung, Donghwa

    2016-09-01

    The interactions between fish gelatin (FG) and sodium alginate (AL) in aqueous solutions were investigated at 25°C by turbidimetric acid titration, zeta potentiometry, dynamic light scattering, methylene blue spectrophotometry, confocal microscopy, and three types of state diagram. FG formed solid-state insoluble complexes, i.e., precipitates, with AL, mainly by electrostatic attractions; the complex formation was significantly influenced by pH, FG-to-AL weight ratio, total biopolymer concentration (CT), and ionic strength. The insoluble complexes formed below a boundary pH (pHφ1) underwent continuous aggregation during acid titration, until immediate visible precipitation occurred at another boundary pH (pHp). The formation and aggregation of insoluble complexes were facilitated by increasing CT or adding small amounts of NaCl, but were greatly suppressed in the presence of high NaCl concentration. The insoluble complexes were formed reversibly depending on pH and transformed to a coupled gel network after 24h incubation, depending on pH, CT, and ionic strength. PMID:27185129

  17. Composite alginate gels for tunable cellular microenvironment mechanics

    Science.gov (United States)

    Khavari, Adele; Nydén, Magnus; Weitz, David A.; Ehrlicher, Allen J.

    2016-01-01

    The mechanics of the cellular microenvironment can be as critical as biochemistry in directing cell behavior. Many commonly utilized materials derived from extra-cellular-matrix create excellent scaffolds for cell growth, however, evaluating the relative mechanical and biochemical effects independently in 3D environments has been difficult in frequently used biopolymer matrices. Here we present 3D sodium alginate hydrogel microenvironments over a physiological range of stiffness (E = 1.85 to 5.29 kPa), with and without RGD binding sites or collagen fibers. We use confocal microscopy to measure the growth of multi-cellular aggregates (MCAs), of increasing metastatic potential in different elastic moduli of hydrogels, with and without binding factors. We find that the hydrogel stiffness regulates the growth and morphology of these cell clusters; MCAs grow larger and faster in the more rigid environments similar to cancerous breast tissue (E = 4–12 kPa) as compared to healthy tissue (E = 0.4–2 kpa). Adding binding factors from collagen and RGD peptides increases growth rates, and change maximum MCA sizes. These findings demonstrate the utility of these independently tunable mechanical/biochemistry gels, and that mechanical confinement in stiffer microenvironments may increase cell proliferation. PMID:27484403

  18. Composite alginate gels for tunable cellular microenvironment mechanics

    Science.gov (United States)

    Khavari, Adele; Nydén, Magnus; Weitz, David A.; Ehrlicher, Allen J.

    2016-08-01

    The mechanics of the cellular microenvironment can be as critical as biochemistry in directing cell behavior. Many commonly utilized materials derived from extra-cellular-matrix create excellent scaffolds for cell growth, however, evaluating the relative mechanical and biochemical effects independently in 3D environments has been difficult in frequently used biopolymer matrices. Here we present 3D sodium alginate hydrogel microenvironments over a physiological range of stiffness (E = 1.85 to 5.29 kPa), with and without RGD binding sites or collagen fibers. We use confocal microscopy to measure the growth of multi-cellular aggregates (MCAs), of increasing metastatic potential in different elastic moduli of hydrogels, with and without binding factors. We find that the hydrogel stiffness regulates the growth and morphology of these cell clusters; MCAs grow larger and faster in the more rigid environments similar to cancerous breast tissue (E = 4–12 kPa) as compared to healthy tissue (E = 0.4–2 kpa). Adding binding factors from collagen and RGD peptides increases growth rates, and change maximum MCA sizes. These findings demonstrate the utility of these independently tunable mechanical/biochemistry gels, and that mechanical confinement in stiffer microenvironments may increase cell proliferation.

  19. Nanospheres of alginate prepared through w/o emulsification and internal gelation with nanoparticles of CaCO3

    NARCIS (Netherlands)

    Paques, J.P.; Sagis, L.M.C.; Rijn, van C.J.M.; Linden, van der E.

    2014-01-01

    Gelled nanospheres of alginate are prepared through a single step technique involving emulsification and gelation. CaCO3 nanoparticles, together with glucono delta-lactone (GDL), are dispersed in an alginate solution, which is subsequently dispersed in an oil phase and followed by gelation of the al

  20. SMALL SCALE PRODUCTION AND CHARACTERIZATION OF ALGINATE FROM AZOTOBACTER CHROOCOCCUM USING DIFFERENT SUBSTRATES UNDER VARIOUS STRESS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Gayathri Pandurangan

    2013-03-01

    Full Text Available Alginates form an important family of biopolymers. These are linear polysaccharides composed of variable amounts of (1–4-β-D-mannuronic acid and its epimer, α-L-guluronic acid. Currently, commercial alginates are extracted from marine brown algae. Considering the merits of bacterial alginates, optimal fermentation conditions aiming at the maximization of alginate using bacterium Azotobacter chroococcum from different substrates were examined. Whey, molasses, ammonium nitrate, starch, yeast extract, butanol, mannitol, and glucose have been used. The alginate obtained from whey (45.15%, ammonium nitrate (46.02% and butanol (47.3% varied. Among the physical stress conditions, the production of alginate was maximum at heat shock 50 0C for 30min (42.96% followed by 41.29% on UV radiation for 10 min. At pH 7 and 8 the alginate produced was 44.63% and 46.64% respectively. Carbazole reagent was used to recognize alginate; it was lyophilized and quantitated by gas chromatography.

  1. Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium.

    Science.gov (United States)

    Belščak-Cvitanović, Ana; Komes, Draženka; Karlović, Sven; Djaković, Senka; Spoljarić, Igor; Mršić, Gordan; Ježek, Damir

    2015-01-15

    Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine. PMID:25149001

  2. Preparation and anatomical distribution study of 67Ga-alginic acid nanoparticles for SPECT purposes in rainbow trout (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Heidarieh Marzieh

    2014-12-01

    Full Text Available Ergosan contains 1% alginic acid extracted from two brown sea weeds. Little is known about the target organs and anatomical distribution of Ergosan (alginic acid in fish. Therefore, feasibility of developing alginic acid nanoparticles to detect target organ in rainbow trout is interesting. To make nanoparticles, Ergosan extract (alginic acid was irradiated at 30 kGy in a cobalt-60 irradiator and characterized by transmission electron microscopy (TEM and Fourier transform infrared spectroscopy (FTIR. Results from TEM images showed that particle sizes of irradiated alginic acid ranged from 30 to 70 nm. The FTIR results indicated that gamma irradiation had no significant influence on the basic structure of alginic acid. Later, alginic acid nanoparticles were successively labelled with 67Ga-gallium chloride. The biodistribution of irradiated Ergosan in normal rainbow trout showed highest uptake in intestine and kidney and then in liver and kidney at 4- and 24-h post injection, respectively. Single-photon emission computed tomography (SPECT images also demonstrated target specific binding of the tracer at 4- and 24-h post injection. In conclusion, the feed supplemented with alginic acid nanoparticles enhanced SPECT images of gastrointestinal morphology and immunity system in normal rainbow trout.

  3. The study of the structural properties of very low viscosity sodium alginate by small-angle neutron scattering

    Science.gov (United States)

    Badita, C. R.; Aranghel, D.; Radulescu, A.; Anitas, E. M.

    2016-03-01

    Sodium alginate is a linear polymer extract from brown algae and it is used in the biomedical, food, cosmetics and pharmaceutical industries as solution property modifiers and gelling agents. But despite the extensive studies of the alginate gelation process, still some fundamental questions remain unresolved. The fractal behavior of very low viscosity sodium alginate solutions and their influence on the critical gelation of alginate induced by Ca2+ ions were investigated using Small-Angle Neutron Scattering (SANS) measurements. SANS data are interpreted using both standard linear plots and the Beaucage model. The scattering intensity is dependent by alginate concentration and Ca2+ concentration. From a critical concentration of 1.0 % w/w our polymer swelled forming spherical structures with rough surfaces. Also the addition of the salt induces the collapse and the appearance of the aggregation and clusters formation.

  4. Characterization of the flow behavior of alginate/hydroxyapatite mixtures for tissue scaffold fabrication

    International Nuclear Information System (INIS)

    Mixtures of alginate and hydroxyapatite (HA) are promising materials for biomedical applications such as the fabrication of tissue scaffolds. In this paper, the flow behavior of alginate/HA mixtures was investigated and determined to be dependent on the concentration of both alginate and HA, and temperature. The relationships were mathematically established and verified with experimental results. As applied to the tissue scaffold fabrication, the flow rate of the biomaterial solution was predicted from the established flow behavior and verified by experiments. On this basis, the moving speed of the needle was determined and used in the tissue scaffold fabrication. The results obtained show that the knowledge of the flow behavior is essential to the fabrication of tissue scaffolds with an interconnected microstructure.

  5. Alginic acid and hyaluronic acid, effective stabilizers of carthamin red colour in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Koshi Saito

    2014-02-01

    Full Text Available Sodium salts and free forms of two heterosaccharides, alginic and hyaluronic acids were mixed with carthamin in a buffer at pH 5.5 and their preservation effects of carthamin red colour were screened after incubation for 24 h at 3-5oC in the dark. The effects observed were (alginic acid/hyaluronic acid, % on average: 69.3/60.3, for which the values are higher by 40.9 and 29.1%, respectively, compared with those of the control which was conducted with no addition of heterosaccharides. Alginic acid is a more promising stabilizer than haluronic acid, indicating that active groups such as hydroxyls, carboxyls and amino groups on the building units of the macromolecules are associated closely with the carthamin red colour preservation. The empirical outcomes are referred to the practical application of carthamin as a colourant of food products.

  6. Preparation and characterization of. beta. -D-glucosidase immobilized in calcium alginate

    Energy Technology Data Exchange (ETDEWEB)

    Krasniak, S. R.; Smith, R. D.

    1982-01-01

    Enzymatic hydrolysis of biomass to produce glucose may become feasible if an inexpensive method to reuse the enzyme can be found. This study investigated one such method whereby ..beta..-D-glucosidase (E.C. 3.2.1.21) was immobilized in calcium alginate gel spheres, which were shown to catalyze the hydrolysis of cellobiose to glucose. There was a loss of 49% of the enzyme from the alginate slurry during gelation. After gelation, in the stable gel spheres, there was a 37% retention of the enzyme activity that was actually immobilized. The reason for the loss in activity was investigated and may be caused by inhibition of the enzyme within the sphere by the calcium cations and the alginate anions also present. Mass transfer effects were minimal in this system and were not responsible for the activity loss.

  7. Microencapsulation in Alginate and Chitosan Microgels to Enhance Viability of Bifidobacterium longum for Oral Delivery

    Science.gov (United States)

    Yeung, Timothy W.; Üçok, Elif F.; Tiani, Kendra A.; McClements, David J.; Sela, David A.

    2016-01-01

    Probiotic microorganisms are incorporated into a wide variety of foods, supplements, and pharmaceuticals to promote human health and wellness. However, maintaining bacterial cell viability during storage and gastrointestinal transit remains a challenge. Encapsulation of bifidobacteria within food-grade hydrogel particles potentially mitigates their sensitivity to environmental stresses. In this study, Bifidobacterium longum subspecies and strains were encapsulated in core-shell microgels consisting of an alginate core and a microgel shell. Encapsulated obligate anaerobes Bifidobacterium longum subsp. infantis and Bifidobacterium longum subsp. longum exhibited differences in viability in a strain-dependent manner, without a discernable relationship to subspecies lineage. This includes viability under aerobic storage conditions and modeled gastrointestinal tract conditions. Coating alginate microgels with chitosan did not improve viability compared to cells encapsulated in alginate microgels alone, suggesting that modifying the surface charge alone does not enhance delivery. Thus hydrogel beads have great potential for improving the stability and efficacy of bifidobacterial probiotics in various nutritional interventions.

  8. Functionalised alginate flow seeding microparticles for use in Particle Image Velocimetry (PIV).

    Science.gov (United States)

    Varela, Sylvana; Balagué, Isaac; Sancho, Irene; Ertürk, Nihal; Ferrando, Montserrat; Vernet, Anton

    2016-03-01

    Alginate microparticles as flow seeding fulfil all the requirements that are recommended for the velocity measurements in Particle Image Velocimetry (PIV). These spherical microparticles offer the advantage of being environmentally friendly, having excellent seeding properties and they can be produced via a very simple process. In the present study, the performances of alginate microparticles functionalised with a fluorescent dye, Rhodamine B (RhB), for PIV have been studied. The efficacy of fluorescence is appreciated in a number of PIV applications since it can boost the signal-to-noise ratio. Alginate microparticles functionalised with RhB have high emission efficiency, desirable match with fluid density and controlled size. The study of the particles behaviour in strong acid and basic solutions and ammonia is also included. This type of particles can be used for measurements with PIV and Planar Laser Induced Fluorescence (PLIF) simultaneously, including acid-base reactions. PMID:26878165

  9. Biosorption of cadmium, lead and copper with calcium alginate xerogels and immobilized Fucus vesiculosus

    International Nuclear Information System (INIS)

    This paper determines the effect of immobilized brown alga Fucus vesiculosus in the biosorption of heavy metals with alginate xerogels. Immobilization increased the kinetic uptakes and intraparticle diffusion rates of the three metals. The Langmuir maximum biosorption capacity increased twofold for cadmium, 10 times for lead, and decreased by half for copper. According to this model, the affinity of the metals for the biomass was as follows: Cu > Pb > Cd without alga and Pb > Cu > Cd with alga. FITR confirmed that carboxyl groups were the main groups involved in the metal uptake. Calcium in the gels was displaced by heavy metals from solution according to the 'egg-box' model. The restructured gel matrix became more uniform and organized as shown by scanning electron microscopy (SEM) characterization. F. vesiculosus immobilized in alginate xerogels constitutes an excellent biosorbent for cadmium, lead and copper, sometimes surpassing the biosorption performance of alginate alone and even the free alga

  10. Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae

    DEFF Research Database (Denmark)

    Laue, H.; Schenk, A.; Li, H.;

    2006-01-01

    Exopolysaccharides (EPSs) play important roles in the attachment of bacterial cells to a surface and/or in building and maintaining the three-dimensional, complex structure of bacterial biofilms. To elucidate the spatial distribution and function of the EPSs levan and alginate during biofilm...... formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser...... scanning microscopy with fluorescently labelled lectins was applied to investigate the spatial distribution of levan and an additional as yet unknown EPS in flow-chamber biofilms. Concanavalin A (ConA) bound specifically to levan and accumulated in cell-depleted voids in the centres of microcolonies and in...

  11. Conservation of Williams pear using edible coating with alginate and carrageenan

    Directory of Open Access Journals (Sweden)

    Kessiane Silva de Moraes

    2012-12-01

    Full Text Available The aim of this study was to evaluate the physical and chemical parameters of Williams pear, stored at 25 ºC for 15 days, with and without edible coating. Edible coatings prepared with alginate 2% and carrageenan 0.5% were tested. The analyses carried out on the samples were: weight loss, pH, soluble solids, firmness, and color. The edible coatings were characterized in terms of mechanical properties, permeability, thickness, and opacity. The results show that the application of edible coatings with carrageenan and alginate in pears influenced physical and chemical characteristics such as weight loss, pH, total soluble solids, color, and firmness of the fruit. However, the alginate coating showed the best results on pear conservation since it had lower water vapor permeability and greater tensile strength, and therefore it can be used as a protective film on these fruits.

  12. Immobilization of chemically modified horse radish peroxidase within activated alginate beads

    Directory of Open Access Journals (Sweden)

    Spasojević Dragica

    2014-01-01

    Full Text Available Immobilization of horse radish peroxidase (HRP within alginate beads was improved by chemical modification of the enzyme and polysaccharide chains. HRP and alginate were oxidized by periodate and subsequently modified with ethylenediamine. Highest specific activity of 0.43 U/ml of gel and 81 % of bound enzyme activity was obtained using aminated HRP and alginate oxidized by periodate. Immobilized enzyme retained 75 % of original activity after 2 days of incubation in 80 % (v/v dioxane and had increased activity at basic pH values compared to native enzyme. During repeated use in batch reactor for pyrogallol oxidation immobilized peroxidase retained 75 % of original activity. [Projekat Ministarstva nauke Republike Srbije, br. ON173017 i br. ON172049

  13. Optimization of keratin/alginate scaffold using RSM and its characterization for tissue engineering.

    Science.gov (United States)

    Gupta, Pratima; Nayak, Kush Kumar

    2016-04-01

    The scaffold for tissue engineering was fabricated from a binary blend of keratin/alginate. The concentration and ratio of keratin and alginate was optimized by response surface methodology in a scaffold. The structural compatibility between keratin and alginate was examined by X-ray diffractometer and Fourier transforms infrared spectroscopy. Apparent porosity of the scaffold was calculated by Archimedes principles and its observed value of was found 96.25 ± 0.04%. The pore size of the scaffold was observed in the range between 10 and 200 μm. Tensile strength (0.33 ± 0.26 MPa) and percent of elongation at break (23.33 ± 2.52%) are the reported mechanical strength of the scaffold. Positive antimicrobial activity and in vitro degradation further confirms the fabrication of a scaffold required for tissue engineering application. PMID:26691383

  14. Quaternary polymethacrylate-sodium alginate films: effect of alginate block structures and use for sustained release tablets.

    Science.gov (United States)

    Pongjanyakul, Thaned; Khuathan, Natnicha

    2016-06-01

    The objectives in this study were to characterize quaternary polymethacrylate-sodium alginate (QPM-SA) films prepared using high G block or high M block SA (GSA or MSA, respectively), and to investigate the effects of QPM-SA ratios, film-coating levels and SA block structures on propranolol HCl (PPN) released from coated tablets. The results demonstrated that GSA and MSA shared a similar interaction mechanism with QPM. The QPM-GSA films had higher puncture strength than the QPM-MSA films in dry and wet states, whereas the % elongations were not different. The drug permeability of the QPM-GSA films was lower than that of the QPM-MSA films in both acidic and neutral media, but higher water uptake of the QPM-GSA films was found at neutral pH. Moreover, the QPM-MSA-coated tablets had a greater PPN release rate than the QPM-GSA-coated tablets, and drug release was dependent on the film-coating levels. In addition, the QPM-SA films at a ratio of 4:0.5 produced a stronger film and could sustain PPN release. These results indicate that the QPM-GSA films had greater film strength and lower drug permeability than the QPM-MSA films. Additionally, the QPM-SA films have a strong potential for use in sustained-release tablets. PMID:25757646

  15. Enhanced aggregation of alginate-coated iron oxide (hematite) nanoparticles in the presence of calcium, strontium, and barium cations.

    Science.gov (United States)

    Chen, Kai Loon; Mylon, Steven E; Elimelech, Menachem

    2007-05-22

    Early-stage aggregation kinetics studies of alginate-coated hematite nanoparticles in solutions containing alkaline-earth metal cations revealed enhanced aggregation rates in the presence of Ca2+, Sr2+, and Ba2+, but not with Mg2+. Transmission electron microscopy (TEM) imaging of the aggregates provided evidence that alginate gel formation was essential for enhanced aggregation to occur. Dynamic light scattering (DLS) aggregation results clearly indicated that a much lower concentration of Ba2+ compared to Ca2+ and Sr2+ was required to achieve a similar degree of enhanced aggregation in each system. To elucidate the relationship between the alginate's affinities for divalent cations and the enhanced aggregation of the alginate-coated hematite nanoparticles, atomic force microscopy (AFM) was employed to probe the interaction forces between alginate-coated hematite surfaces under the solution chemistries used for the aggregation study. Maximum adhesion forces, maximum pull-off distances, and the work of adhesion were used as indicators to gauge the alginate's affinity for the divalent cations and the resulting attractive interactions between alginate-coated hematite nanoparticles. The results showed that alginate had higher affinity for Ba2+ than either Sr2+ or Ca2+. This same trend was consistent with the cation concentrations required for comparable enhanced aggregation kinetics, suggesting that the rate of alginate gel formation controls the enhanced aggregation kinetics. An aggregation mechanism incorporating the gelation of alginate is proposed to explain the accelerated aggregate growth in the presence of Ca2+, Sr2+, and Ba2+. PMID:17469860

  16. Acute effect of alginate-based preload on satiety feelings, energy intake, and gastric emptying rate in healthy subjects.

    Science.gov (United States)

    Georg Jensen, Morten; Kristensen, Mette; Belza, Anita; Knudsen, Jes C; Astrup, Arne

    2012-09-01

    Viscous dietary fibers such as sodium alginate extracted from brown seaweed have received much attention lately for their potential role in energy regulation through the inhibition of energy intake and increase of satiety feelings. The aim of our study was to investigate the effect on postprandial satiety feelings, energy intake, and gastric emptying rate (GER), by the paracetamol method, of two different volumes of an alginate-based preload in normal-weight subjects. In a four-way placebo-controlled, double-blind, crossover trial, 20 subjects (age: 25.9 ± 3.4 years; BMI: 23.5 ± 1.7 kg/m(2)) were randomly assigned to receive a 3% preload concentration of either low volume (LV; 9.9 g alginate in 330 ml) or high volume (HV; 15.0 g alginate in 500 ml) alginate-based beverage, or an iso-volume placebo beverage. The preloads were ingested 30 min before a fixed breakfast and again before an ad libitum lunch. Consumption of LV-alginate preload induced a significantly lower (8.0%) energy intake than the placebo beverage (P = 0.040) at the following lunch meal, without differences in satiety feelings or paracetamol concentrations. The HV alginate significantly increased satiety feelings (P = 0.038), reduced hunger (P = 0.042) and the feeling of prospective food consumption (P = 0.027), and reduced area under the curve (iAUC) paracetamol concentrations compared to the placebo (P = 0.05). However, only a 5.5% reduction in energy intake was observed for HV alginate (P = 0.20). Although they are somewhat contradictory, our results suggest that alginate consumption does affect satiety feelings and energy intake. However, further investigation on the volume of alginate administered is needed before inferring that this fiber has a possible role in short-term energy regulation. PMID:21779093

  17. Influence of mechanical properties of alginate-based substrates on the performance of Schwann cells in culture.

    Science.gov (United States)

    Ning, Liqun; Xu, Yitong; Chen, Xiongbiao; Schreyer, David J

    2016-06-01

    In tissue engineering, artificial tissue scaffolds containing living cells have been studied for tissue repair and regeneration. Notably, the performance of these encapsulated-in-scaffolds cells in terms of cell viability, proliferation, and expression of function during and after the scaffold fabrication process, has not been well documented because of the influence of mechanical, chemical, and physical properties of the scaffold substrate materials. This paper presents our study on the influence of mechanical properties of alginate-based substrates on the performance of Schwann cells, which are the major glial cells of peripheral nervous system. Given the fact that alginate polysaccharide hydrogel has poor cell adhesion properties, in this study, we examined several types of cell-adhesion supplements and found that alginate covalently modified with RGD peptide provided improved cell proliferation and adhesion. We prepared alginate-based substrates for cell culture using varying alginate concentrations for altering their mechanical properties, which were confirmed by compression testing. Then, we examined the viability, proliferation, morphology, and expression of the extracellular matrix protein laminin of Schwann cells that were seeded on the surface of alginate-based substrates (or 2D culture) or encapsulated within alginate-based substrates (3D cultures), and correlated the examined cell performance to the alginate concentration (or mechanical properties) of hydrogel substrates. Our findings suggest that covalent attachment of RGD peptide can improve the success of Schwann cell encapsulation within alginate-based scaffolds, and provide guidance for regulating the mechanical properties of alginate-based scaffolds containing Schwann cells for applications in peripheral nervous system regeneration and repair. PMID:27012482

  18. Characterization of surface charge and mechanical properties of chitosan/alginate based biomaterials

    International Nuclear Information System (INIS)

    This study aims to examine mechanical properties and surface charge characteristics of chitosan/alginate-based films for biomedical applications. By varying the concentrations of chitosan and alginate, we have developed films with varying surface charge densities and mechanical characteristics. The surface charge densities of these films were determined by applying an analytical model on force curves derived from an atomic force microscope (AFM). The average surface charge densities of films containing 60% chitosan and 80% chitosan were found to be - 0.46 mC/m2 and - 0.32 mC/m2, respectively. The surface charge density of 90% chitosan containing films was found to be neutral. The elastic moduli and the water content were found to be decreasing with increasing chitosan concentration. The films with 60%, 80% and 90% chitosan gained 93.5 ± 6.6%, 217.1 ± 22.1% and 396.8 ± 67.5% of their initial weight, respectively. Their elastic moduli were found to be 2.6 ± 0.14 MPa, 1.9 ± 0.27 MPa and 0.93 ± 0.12 MPa, respectively. The trend observed in the mechanical response of these films has been attributed to the combined effect of the concentration of polyelectrolyte complexes (PEC) and the amount of water absorbed. The Fourier transform infrared spectroscopy experiments indicate the presence of higher alginate on the surface of the films compared to the bulk in all films. The presence of higher alginate on surface is consistent with negative surface charge densities of these films, determined from AFM experiments. Highlights: → Chitosan/alginate based fibrous polyelectrolyte complex films were developed. → The average surface charge density of the films was determined using AFM. → Elastic modulus of the films increased with increase in PEC content. → FTIR analysis indicated higher alginate content on surface compared to bulk.

  19. Transplantation of Neural Stem Cells Cultured in Alginate Scaffold for Spinal Cord Injury in Rats

    Science.gov (United States)

    Sharafkhah, Ali; Koohi-Hosseinabadi, Omid; Semsar-Kazerooni, Maryam

    2016-01-01

    Study Design This study investigated the effects of transplantation of alginate encapsulated neural stem cells (NSCs) on spinal cord injury in Sprague-Dawley male rats. The neurological functions were assessed for 6 weeks after transplantation along with a histological study and measurement of caspase-3 levels. Purpose The aim of this study was to discover whether NSCs cultured in alginate transplantation improve recovery from spinal cord injury. Overview of Literature Spinal cord injury is one of the leading causes of disability and it has no effective treatment. Spinal cord injury can also cause sensory impairment. With an impetus on using stem cells therapy in various central nervous system settings, there is an interest in using stem cells for addressing spinal cord injury. Neural stem cell is one type of stem cells that is able to differentiate to all three neural lineages and it shows promise in spinal injury treatment. Furthermore, a number of studies have shown that culturing NSCs in three-dimensional (3D) scaffolds like alginate could enhance neural differentiation. Methods The NSCs were isolated from 14-day-old rat embryos. The isolated NSCs were cultured in growth media containing basic fibroblast growth factor and endothelial growth factor. The cells were characterized by differentiating to three neural lineages and they were cultured in an alginate scaffold. After 7 days the cells were encapsulated and transplanted in a rat model of spinal cord injury. Results Our data showed that culturing in an alginate 3D scaffold and transplantation of the NSCs could improve neurological outcome in a rat model of spinal cord injury. The inflammation scores and lesion sizes and also the activity of caspase-3 (for apoptosis evaluation) were less in encapsulated neural stem cell transplantation cases. Conclusions Transplantation of NSCs that were cultured in an alginate scaffold led to a better clinical and histological outcome for recovery from spinal cord injury in

  20. Release of angiogenic growth factors from cells encapsulated in alginate beads with bioactive glass.

    Science.gov (United States)

    Keshaw, Hussila; Forbes, Alastair; Day, Richard M

    2005-07-01

    Attempts to stimulate therapeutic angiogenesis using gene therapy or delivery of recombinant growth factors, such as vascular endothelial growth factor (VEGF), have failed to demonstrate unequivocal efficacy in human trials. Bioactive glass stimulates fibroblasts to secrete significantly increased amounts of angiogenic growth factors and therefore has a number of potential applications in therapeutic angiogenesis. The aim of this study was to assess whether it is possible to encapsulate specific quantities of bioactive glass and fibroblasts into alginate beads, which will secrete growth factors capable of stimulating angiogenesis. Human fibroblasts (CCD-18Co) were encapsulated in alginate beads with specific quantities of 45S5 bioactive glass and incubated in culture medium (0-17 days). The conditioned medium was collected and assayed for VEGF or used to assess its ability to stimulate angiogenesis by measuring the proliferation of human dermal microvascular endothelial cells. At 17 days the beads were lysed and the amount of VEGF retained by the beads measured. Fibroblasts encapsulated in alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass particles secreted increased quantities of VEGF compared with cells encapsulated with 0% or 1% (w/v) 45S5 bioactive glass particles. Lysed alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass contained significantly more VEGF (p<0.01) compared with beads containing no glass particles. Endothelial cell proliferation was significantly increased (p<0.01) by conditioned medium collected from alginate beads containing 0.1% (w/v) 45S5 bioactive glass particles. The results of this study demonstrate that bioactive glass and fibroblasts can be successfully incorporated into alginate beads for use in delivering angiogenic growth factors. With further optimization, this technique offers a novel delivery device for stimulating therapeutic angiogenesis. PMID:15664644

  1. Isolation and identification of a novel alginate-degrading bacterium, Ochrobactrum sp.

    Directory of Open Access Journals (Sweden)

    Xiao-wei Zhao

    2008-03-01

    Full Text Available An alginate-degrading bacterium, identified as Ochrobactrum sp. on the basis of 16S rDNA gene sequencing, was isolated from brown algal samples collected from the waters in close vicinity to the Dongtou Isles in the East China Sea. The strain, designated WZUH09-1, is a short rod, gram-negative, obligatory aerobic, grows under the following conditions: 5-40oC, pH 3-9, and 0-2 times of the seawater concentration, and is able to depolymerize alginates with higher enzyme activity than that of others reported so far.

  2. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    OpenAIRE

    Uzaşçı Sesil; Tezcan Filiz; Bedia Erim F.

    2014-01-01

    Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI) was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI) adsorpt...

  3. Quantitative analysis of potentially toxic metals in alginates for dental use

    OpenAIRE

    A. S. Braga; A. B.C.E.B. CATIRSE; VAZ, L. G.; A. C.C. Spadaro

    2009-01-01

    Alginate is one the materials most employed in practice to make dental impressions. Substances like zinc, cadmium and lead silicate, which are included in several alginate brands with the aim of improving their physical, chemical and mechanical properties, are a source of serious concern as regards their toxicity. The most serious chronic effect of oral exposure to c...

  4. Quantitative analysis of potentially toxic metals in alginates for dental use

    OpenAIRE

    VAZ, L. G.; A. C.C. Spadaro; A. B.C.E.B. CATIRSE; A. S. Braga

    2009-01-01

    Alginate is one the materials most employed in practice to make dental impressions. Substances like zinc, cadmium and lead silicate, which are included in several alginate brands with the aim of improving their physical, chemical and mechanical properties, are a source of serious concern as regards their toxicity. The most serious chronic effect of oral exposure to c...

  5. Daily ingestion of alginate reduces energy intake in free-living subjects

    OpenAIRE

    Paxman, J. R.; Richardson, J. C.; Dettmar, P. W.; Corfe, B.M

    2008-01-01

    Sodium alginate is a seaweed-derived fibre that has previously been shown to moderate appetite in models of acute feeding. The mechanisms underlying this effect may include slowed gastric clearance and attenuated uptake from the small intestine. In order to assess whether alginate could be effective as a means of appetite control in free-living adults, 68 males and females (BMI range: 18.50-32.81 kgl M-2) completed this randomised, controlled two-way crossover intervention to compare the effe...

  6. Microencapsulation by Spray Coagulation of Diltiazem HCl in Calcium Alginate-Coated Chitosan

    OpenAIRE

    Tapia, Cristián; Montezuma, Víctor; Yazdani-Pedram, Mehrdad

    2008-01-01

    The aim of this work was to develop a procedure for encapsulation of diltiazem HCl by spray coagulation. Factors affecting the formulations such as the effect of NaCl on the solubility of diltiazem in alginate solution, surface tension, pH, viscosity of the coagulation medium, and the effect of drug load on drug release were studied. The drug load was increased substantially from 10 up to 320 mg/mL by adding 1.2% w/v NaCl in 1% w/v alginate solution. More stable microcapsules were obtained at...

  7. Brown adipogenesis of mouse embryonic stem cells in alginate microstrands

    Science.gov (United States)

    Unser, Andrea Mannarino

    The ability of brown adipocytes (fat cells) to dissipate energy as heat shows great promise for the treatment of obesity and other metabolic disorders. Employing pluripotent stem cells, with an emphasis on directed differentiation, may overcome many issues currently associated with primary fat cell cultures. However, brown adipocytes are difficult to transplant in vivo due to the instability of fat, in terms of necrosis and neovascularization, once injected. Thus, 3D cell culture systems that have the potential to mimic adipogenic microenvironments are needed, not only to advance brown fat implantation, but also to better understand the role of brown adipocytes in treating obesity. To address this need, we created 3D "Brown-Fat-in-Microstrands" by microfluidic synthesis of alginate hydrogel microstrands that encapsulated cells and directly induced cell differentiation into brown adipocytes, using mouse embryonic stem cells (ESCs) as a model of pluripotent stem cells and brown preadipocytes as a positive control. The effect of hydrogel formation parameters on brown adipogenesis was studied, leading to the establishment of "Brown-Fat-in-Microstrands". Brown adipocyte differentiation within microstrands was confirmed by lipid droplet accumulation, immunocytochemistry and qPCR analysis of gene expression of brown adipocyte marker uncoupling protein 1 (UCP1) in addition to adipocyte marker expression. Compared to a 2D approach, 3D differentiated "Brown-Fat-in-Microstrands" exhibited higher level of brown adipocyte marker expression. The functional analysis of "Brown-Fat-in-Microstrands" was attempted by measuring the mitochondrial activity of ESC-differentiated brown adipocytes in 3D using Seahorse XF24 3 Extracellular Flux Analyzer. The ability to create "Brown-Fat-in-Microstrands" from pluripotent stem cells opens up a new arena to understanding brown adipogenesis and its implications in obesity and metabolic disorders.

  8. Phenol removal by soluble and alginate entrapped turnip peroxidase

    Directory of Open Access Journals (Sweden)

    Ahmed Azizi

    2014-12-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 This paper is a comparative study of phenol biodegradation by soluble and alginate entrapped turnip (Brassica rapa peroxidase. The effects of relevant factors on the process such as pH, temperature, concentration of H2O2, phenol concentration, enzyme activity and contact time were evaluated in order to optimize the conditions for maximum phenol removal.  Results showed that the obtained average removal yield under optimal conditions was 93%.  The process duration was 3 hours. The reaction is conducted in aqueous medium under optimal pH 7 and temperature of 40 °C. The highest removal percentage was obtained for phenol concentrations of 80 and 46 mg L-1 with soluble and entrapped enzyme respectively.  /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  9. Formulation of essential oil-loaded chitosan–alginate nanocapsules

    Directory of Open Access Journals (Sweden)

    Dheebika Natrajan

    2015-09-01

    Full Text Available Naturally occurring polymers such as alginate (AL and chitosan (CS are widely used in biomedical and pharmaceutical fields in various forms such as nanoparticles, capsules, and emulsions. These polymers have attractive applications in drug delivery because of their biodegradability, biocompatibility, and nontoxic nature. The pharmaceutical applications of essential oils such as turmeric oil and lemongrass oil are well-known, and their active components, ar-turmerone and citral, respectively, are known for their antibacterial, antifungal, antioxidant, antimutagenic, and anticarcinogenic properties. However, these essential oils are unstable, volatile, and insoluble in water, which limits their use for new formulations. Therefore, this study focuses on developing a CS–AL nanocarrier for the encapsulation of essential oils. The effects of process parameters such as the effect of heat and the concentrations of AL and CS were investigated. Various physicochemical characterization techniques such as scanning electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy were performed. Results of characterization studies showed that 0.3 mg/mL AL and 0.6 mg/mL CS produced minimum-sized particles (<300 nm with good stability. It was also confirmed that the oil-loaded nanocapsules were hemocompatible, suggesting their use for future biomedical and pharmaceutical applications. Furthermore, the antiproliferative activity of turmeric oil- and lemongrass oil-loaded nanocapsules was estimated using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay in A549 cell lines and it was found that both the nanoformulations had significant antiproliferative properties than the bare oil.

  10. Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

    Science.gov (United States)

    Kaisheva, N. Sh.; Kaishev, A. Sh.

    2015-07-01

    The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.

  11. Fabrication, characterization, and biocompatibility of single-walled carbon nanotube-reinforced alginate composite scaffolds manufactured using freeform fabrication technique.

    Science.gov (United States)

    Yildirim, Eda D; Yin, Xi; Nair, Kalyani; Sun, Wei

    2008-11-01

    Composite polymeric scaffolds from alginate and single-walled carbon nanotube (SWCNT) were produced using a freeform fabrication technique. The scaffolds were characterized for their structural, mechanical, and biological properties by scanning electron microscopy, Raman spectroscopy, tensile testing, and cell-scaffold interaction study. Three-dimensional hybrid alginate/SWCNT tissue scaffolds were fabricated in a multinozzle biopolymer deposition system, which makes possible to disperse and align SWCNTs in the alginate matrix. The structure of the resultant scaffolds was significantly altered due to SWCNT reinforcement, which was confirmed by Raman spectroscopy. Microtensile testing presented a reinforcement effect of SWCNT to the mechanical strength of the alginate struts. Ogden constitutive modeling was utilized to predict the stress-strain relationship of the alginate scaffold, which compared well with the experimental data. Cellular study by rat heart endothelial cell showed that the SWCNT incorporated in the alginate structure improved cell adhesion and proliferation. Our study suggests that hybrid alginate/SWCNT scaffolds are a promising biomaterial for tissue engineering applications. PMID:18506813

  12. Formulation and in vitro characterization of alginate microspheres loaded with diloxanide furoate for colon- specific drug delivery

    Directory of Open Access Journals (Sweden)

    Shukla Shailendra

    2010-01-01

    Full Text Available The aim of the research work was to develop cyst-targeted alginates microspheres of diloxanide furoate (DF for the effective treatment of amoebiasis. Calcium alginates microspheres of DF were prepared using emulsification method using calcium chloride as a cross-linking agent. Alginate is a natural polysaccharide found in brown algae. Alginates are widely used in the food and pharmaceutical industries and have been employed as a matrix for the entrapment of drugs, macromolecules and biological cells. Alginate microspheres produced by the emulsification method using calcium chloride. Formulations were characterized for particle size and shape, surface morphology, entrapment efficiency, and in vitro drug release in simulated gastrointestinal fluids. XRD and differential scanning calorimetery were used to confirm successful entrapment of DF into the alginates microspheres. All the microsphere formulations showed good % drug entrapment (73.82΁1.99. Calcium alginate retarded the release of DF at low pH (1.2 and 4.5 and released microspheres slowly at pH 7.4 in the colon without colonic enzymes.

  13. Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

    Science.gov (United States)

    Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

    2016-01-01

    Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

  14. TRANSPLANTATION OF CRYOPRESERVED FETAL LIVER CELLS SEEDED INTO MACROPOROUS ALGINATE-GELATIN SCAFFOLDS IN RATS WITH LIVER FAILURE

    Directory of Open Access Journals (Sweden)

    D. V. Grizay

    2015-01-01

    Full Text Available Aim. To study the therapeutic potential of cryopreserved fetal liver cells seeded into macroporous alginategelatin scaffolds after implantation to omentum of rats with hepatic failure.Materials and methods.Hepatic failure was simulated by administration of 2-acetyl aminofl uorene followed partial hepatectomy. Macroporous alginate-gelatin scaffolds, seeded with allogenic cryopreserved fetal liver cells (FLCs were implanted into rat omentum. To prevent from colonization of host cells scaffolds were coated with alginate gel shell. Serum transaminase activity, levels of albumin and bilirubin as markers of hepatic function were determined during 4 weeks after failure model formation and scaffold implantation. Morphology of liver and scaffolds after implantation were examined histologically. Results. Macroporous alginate-gelatin scaffolds after implantation to healthy rats were colonized by host cells. Additional formation of alginate gel shell around scaffolds prevented the colonization. Implantation of macroporous scaffolds seeded with cryopreserved rat FLCs and additionally coated with alginate gel shell into omentum of rats with hepatic failure resulted in signifi cant improvement of hepatospecifi c parameters of the blood serum and positive changes of liver morphology. The presence of cells with their extracellular matrix within the scaffolds was confi rmed after 4 weeks post implantation.Conclusion. The data above indicate that macroporous alginate-gelatin scaffolds coated with alginate gel shell are promising cell carriers for the development of bioengineered liver equivalents.

  15. Membrane-anchored MucR mediates nitrate-dependent regulation of alginate production in Pseudomonas aeruginosa

    KAUST Repository

    Wang, Yajie

    2015-04-29

    Alginates exhibit unique material properties suitable for medical and industrial applications. However, if produced by Pseudomonas aeruginosa, it is an important virulence factor in infection of cystic fibrosis patients. The alginate biosynthesis machinery is activated by c-di-GMP imparted by the inner membrane protein, MucR. Here, it was shown that MucR impairs alginate production in response to nitrate in P. aeruginosa. Subsequent site-specific mutagenesis of MucR revealed that the second MHYT sensor motif (MHYT II, amino acids 121–124) of MucR sensor domain was involved in nitrate sensing. We also showed that both c-di-GMP synthesizing and degrading active sites of MucR were important for alginate production. Although nitrate and deletion of MucR impaired alginate promoter activity and global c-di-GMP levels, alginate yields were not directly correlated with alginate promoter activity or c-di-GMP levels, suggesting that nitrate and MucR modulate alginate production at a post-translational level through a localized pool of c-di-GMP. Nitrate increased pel promoter activity in the mucR mutant while in the same mutant the psl promoter activity was independent of nitrate. Nitrate and deletion of mucR did not impact on swarming motility but impaired attachment to solid surfaces. Nitrate and deletion of mucR promoted the formation of biofilms with increased thickness, cell density, and survival. Overall, this study provided insight into the functional role of MucR with respect to nitrate-mediated regulation of alginate biosynthesis. © 2015 Springer-Verlag Berlin Heidelberg

  16. Biosorption of uranium by cross-linked and alginate immobilized residual biomass from distillery spent wash

    International Nuclear Information System (INIS)

    Residual biomass from a whiskey distillery was examined for its ability to function as a biosorbent for uranium. Biomass recovered and lyophilised exhibited a maximum biosorption capacity of 165-170 mg uranium/g dry weight biomass at 15 C. With a view towards the development of continuous or semi-continuous flow biosorption processes it was decided to immobilize the material by (1) cross-linking with formaldehyde and (2) introducing that material into alginate matrices. Cross-linking the recovered biomass resulted in the formation of a biosorbent preparation with a maximum biosorption capacity of 185-190 mg/g dry weight biomass at 15 C. Following immobilization of biomass in alginate matrices it was found that the total amount of uranium bound to the matrix did not change with increasing amounts of biomass immobilized. It was found however, that the proportion of uranium bound to the biomass within the alginate-biomass matrix increased with increasing biomass concentration. Further analysis of these preparations demonstrated that the alginate-biomass matrix had a maximum biosorption capacity of 220 mg uranium/g dry weight of the matrix, even at low concentrations of biomass. (orig.). With 3 figs., 1 tab

  17. Cytotoxicity study of novel water-soluble chitosan derivatives applied as membrane material of alginate microcapsules

    NARCIS (Netherlands)

    Sobol, Marcin; Bartkowiak, Artur; de Haan, Bart; de Vos, Paul

    2013-01-01

    The majority of cell encapsulation systems applied so far are based on polyelectrolyte complexes of alginate and polyvalent metal cations. Although widely used, these systems suffer from the risk of disintegration. This can be partially solved by applying chitosan as additional outer membrane. Howev

  18. CHO immobilization in alginate/poly-L: -lysine microcapsules: an understanding of potential and limitations.

    Science.gov (United States)

    Breguet, Véronique; Gugerli, Raphaël; von Stockar, Urs; Marison, Ian William

    2007-04-01

    Microencapsulation offers a unique potential for high cell density, high productivity mammalian cell cultures. However, for successful exploitation there is the need for microcapsules of defined size, properties and mechanical stability. Four types of alginate/poly-L: -Lysine microcapsules, containing recombinant CHO cells, have been investigated: (a) 800 mum liquid core microcapsules, (b) 500 mum liquid core microcapsules, (c) 880 mum liquid core microcapsules with a double PLL membrane and (d) 740 mum semi-liquid core microcapsules. With encapsulated cells a reduced growth rate was observed, however this was accompanied by a 2-3 fold higher specific production rate of the recombinant protein. Interestingly, the maximal intracapsular cell concentration was only 8.7 x 10(7) cell mL(-1), corresponding to a colonization of 20% of the microcapsule volume. The low level of colonization is unlikely to be due to diffusional limitations since reduction of microcapsule size had no effect. Measurement of cell leaching and mechanical properties showed that liquid core microcapsules are not suitable for continuous long-term cultures (>1 month). By contrast semi-liquid core microcapsules were stable over long periods with a constant level of cell colonization (varphi = 3%). This indicates that the alginate in the core plays a predominant role in determining the level of microcapsule colonization. This was confirmed by experiments showing reduced growth rates of batch suspension cultures of CHO cells in medium containing dissolved alginate. Removal of this alginate would therefore be expected to increase microcapsule colonization. PMID:19003193

  19. Growth and metabolic activity of conventional and non-conventional yeasts immobilized in foamed alginate.

    Science.gov (United States)

    Kregiel, Dorota; Berlowska, Joanna; Ambroziak, Wojciech

    2013-09-10

    The aim of this research was to study how the cell immobilization technique of forming foamed alginate gels influences the growth, vitality and metabolic activity of different yeasts. Two distinct strains were used, namely conventional yeast (exemplified by Saccharomyces cerevisiae) and a non-conventional strain (exemplified by Debaryomyces occidentalis). The encapsulation of the yeast cells was performed by the traditional process of droplet formation, but from a foamed alginate solution. The activities of two key enzymes, succinate dehydrogenase and pyruvate decarboxylase, together with the ATP content were measured in both the free and immobilized cells. This novel method of yeast cell entrapment had some notable effects. The number of living immobilized cells reached the level of 10(6)-10(7) per single bead, and was stable during the fermentation process. Reductions in both enzyme activity and ATP content were observed in all immobilized yeasts. However, S. cerevisiae showed higher levels of ATP and enzymatic activity than D. occidentalis. Fermentation trials with immobilized repitching cells showed that the tested yeasts adapted to the specific conditions. Nevertheless, the mechanical endurance of the carriers and the internal structure of the gel need to be improved to enable broad applications of alginate gels in industrial fermentation processes, especially with conventional yeasts. This is one of the few papers and patents that describe the technique of cell immobilization in foamed alginate and shows the fermentative capacities and activities of key enzymes in immobilized yeast cells. PMID:23931687

  20. Genetically engineered alginate lyase-PEG conjugates exhibit enhanced catalytic function and reduced immunoreactivity.

    Directory of Open Access Journals (Sweden)

    John W Lamppa

    Full Text Available Alginate lyase enzymes represent prospective biotherapeutic agents for treating bacterial infections, particularly in the cystic fibrosis airway. To effectively deimmunize one therapeutic candidate while maintaining high level catalytic proficiency, a combined genetic engineering-PEGylation strategy was implemented. Rationally designed, site-specific PEGylation variants were constructed by orthogonal maleimide-thiol coupling chemistry. In contrast to random PEGylation of the enzyme by NHS-ester mediated chemistry, controlled mono-PEGylation of A1-III alginate lyase produced a conjugate that maintained wild type levels of activity towards a model substrate. Significantly, the PEGylated variant exhibited enhanced solution phase kinetics with bacterial alginate, the ultimate therapeutic target. The immunoreactivity of the PEGylated enzyme was compared to a wild type control using in vitro binding studies with both enzyme-specific antibodies, from immunized New Zealand white rabbits, and a single chain antibody library, derived from a human volunteer. In both cases, the PEGylated enzyme was found to be substantially less immunoreactive. Underscoring the enzyme's potential for practical utility, >90% of adherent, mucoid, Pseudomonas aeruginosa biofilms were removed from abiotic surfaces following a one hour treatment with the PEGylated variant, whereas the wild type enzyme removed only 75% of biofilms in parallel studies. In aggregate, these results demonstrate that site-specific mono-PEGylation of genetically engineered A1-III alginate lyase yielded an enzyme with enhanced performance relative to therapeutically relevant metrics.

  1. Galactosylated alginate-curcumin micelles for enhanced delivery of curcumin to hepatocytes.

    Science.gov (United States)

    P R, Sarika; James, Nirmala Rachel; Kumar P R, Anil; K Raj, Deepa

    2016-05-01

    Galactosylated alginate-curcumin conjugate (LANH2-Alg Ald-Cur) is synthesized for targeted delivery of curcumin to hepatocytes exploiting asialoglycoprotein receptor (ASGPR) on hepatocytes. The synthetic procedure includes oxidation of alginate (Alg), modification of lactobionic acid (LA), grafting of targeting group (modified lactobinic acid, LANH2) and conjugation of curcumin to alginate. Alginate-curcumin conjugate (Alg-Cur) without targeting group is also prepared for the comparison of properties. LANH2-Alg Ald-Cur self assembles to micelle with diameter of 235±5nm and zeta potential of -29mV in water. Cytotoxicity analysis demonstrates enhanced toxicity of LANH2-Alg Ald-Cur over Alg-Cur on HepG2 cells. Cellular uptake studies confirm that LANH2-Alg Ald-Cur can selectively recognize HepG2 cells and shows higher internalization than Alg-Cur conjugate. Results indicate that LANH2-Alg Ald-Cur conjugate micelles are suitable candidates for targeted delivery of curcumin to HepG2 cells. PMID:26774374

  2. Chitosan and alginate types of bio-membrane in fuel cell application: An overview

    Science.gov (United States)

    Shaari, N.; Kamarudin, S. K.

    2015-09-01

    The major problems of polymer electrolyte membrane fuel cell technology that need to be highlighted are fuel crossovers (e.g., methanol or hydrogen leaking across fuel cell membranes), CO poisoning, low durability, and high cost. Chitosan and alginate-based biopolymer membranes have recently been used to solve these problems with promising results. Current research in biopolymer membrane materials and systems has focused on the following: 1) the development of novel and efficient biopolymer materials; and 2) increasing the processing capacity of membrane operations. Consequently, chitosan and alginate-based biopolymers seek to enhance fuel cell performance by improving proton conductivity, membrane durability, and reducing fuel crossover and electro-osmotic drag. There are four groups of chitosan-based membranes (categorized according to their reaction and preparation): self-cross-linked and salt-complexed chitosans, chitosan-based polymer blends, chitosan/inorganic filler composites, and chitosan/polymer composites. There are only three alginate-based membranes that have been synthesized for fuel cell application. This work aims to review the state-of-the-art in the growth of chitosan and alginate-based biopolymer membranes for fuel cell applications.

  3. Invert sugar formation with Saccharomyces cerevisiae cells encapsulated in magnetically responsive alginate microparticles

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2009-01-01

    Roč. 321, - (2009), s. 1478-1481. ISSN 0304-8853 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk(CZ) OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate microbeads * Saccharomyces cerevisiae * invertase Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.204, year: 2009

  4. Microencapsulation of lectin anti-cancer agent and controlled release by alginate beads, biosafety approach.

    Science.gov (United States)

    El-Aassar, M R; Hafez, Elsayed E; El-Deeb, Nehal M; Fouda, Moustafa M G

    2014-08-01

    Hepatocellular carcinoma (HCC) is considered as one of the most aggressive cancer worldwide. In Egypt, the prevalence of HCC is increasing during last years. Recently, drug-loaded microparticles were used to improve the efficiency of various medical treatments. This study is designed to evaluate the anticancer potentialities of lectins against HCC while hinting to its safety usage. The aim is also extended to encapsulate lectins in alginate microbeads for oral drug delivery purposes. The extracted lectins showed anti-proliferative effect against HCC with a percentage of 60.76% by using its nontoxic dose with an up-regulation of P53 gene expression. Concerning the handling of lectin alginate microbeads for oral drug delivery, the prepared lectin alginate beads were ∼100μm in diameter. The efficiency of the microcapsules was checked by scanning electron microscopy, the SEM showed the change on the alginate beads surface revealing the successful lectin encapsulation. The release of lectins from the microbeads depended on a variety of factors as the microbeads forming carriers and the amount-encapsulated lectins. The Pisum sativum extracted lectins may be considered as a promising agent in controlling HCC and this solid dosage form could be suitable for oral administration complemented with/or without the standard HCC drugs. PMID:24857870

  5. Alginate/Poly(γ-glutamic Acid Base Biocompatible Gel for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Wing P. Chan

    2015-01-01

    Full Text Available A technique for synthesizing biocompatible hydrogels by cross-linking calcium-form poly(γ-glutamic acid, alginate sodium, and Pluronic F-127 was created, in which alginate can be cross-linked by Ca2+ from Ca–γ-PGA directly and γ-PGA molecules introduced into the alginate matrix to provide pH sensitivity and hemostasis. Mechanical properties, swelling behavior, and blood compatibility were investigated for each hydrogel compared with alginate and for γ-PGA hydrogel with the sodium form only. Adding F-127 improves mechanical properties efficiently and influences the temperature-sensitive swelling of the hydrogels but also has a minor effect on pH-sensitive swelling and promotes anticoagulation. MG-63 cells were used to test biocompatibility. Gelation occurred gradually through change in the elastic modulus as the release of calcium ions increased over time and caused ionic cross-linking, which promotes the elasticity of gel. In addition, the growth of MG-63 cells in the gel reflected nontoxicity. These results showed that this biocompatible scaffold has potential for application in bone materials.

  6. Exploration of alginate hydrogel/nano zinc oxide composite bandages for infected wounds

    Directory of Open Access Journals (Sweden)

    Mohandas A

    2015-10-01

    Full Text Available Annapoorna Mohandas,* Sudheesh Kumar PT,* Biswas Raja, Vinoth-Kumar Lakshmanan, Rangasamy Jayakumar Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India *These authors contributed equally to this work Abstract: Alginate hydrogel/zinc oxide nanoparticles (nZnO composite bandage was developed by freeze-dry method from the mixture of nZnO and alginate hydrogel. The developed composite bandage was porous with porosity at a range of 60%–70%. The swelling ratios of the bandages decreased with increasing concentrations of nZnO. The composite bandages with nZnO incorporation showed controlled degradation profile and faster blood clotting ability when compared to the KALTOSTAT® and control bandages without nZnO. The prepared composite bandages exhibited excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and methicillin resistant S. aureus (MRSA. Cytocompatibility evaluation of the prepared composite bandages done on human dermal fibroblast cells by Alamar assay and infiltration studies proved that the bandages have a non-toxic nature at lower concentrations of nZnO whereas slight reduction in viability was seen with increasing nZnO concentrations. The qualitative analysis of ex-vivo re-epithelialization on porcine skin revealed keratinocyte infiltration toward wound area for nZnO alginate bandages. Keywords: alginate, hydrogel, ZnO nanoparticle, hemostatic, antimicrobial activity, wound healing

  7. Oil-entrapped sterculia gum-alginate buoyant systems of aceclofenac: development and in vitro evaluation.

    Science.gov (United States)

    Guru, Pravat Ranjan; Nayak, Amit Kumar; Sahu, Rajendra Kumar

    2013-04-01

    The current investigation deals with the development and optimization of oil-entrapped sterculia gum-alginate buoyant beads containing aceclofenac by ionotropic emulsion-gelation technique using 3(2) factorial design. The effect of polymer to drug ratio and sodium alginate to sterculia gum ratio on the drug entrapment efficiency (%), and cumulative drug release after 7 h (%) was optimized. The optimized oil-entrapped sterculia gum-alginate buoyant beads containing aceclofenac (F-O) showed drug entrapment efficiency of 90.92±2.34%, cumulative drug release of 41.65±3.97% after 7 h in simulated gastric fluid (pH 1.2), and well buoyancy over 8 h in simulated gastric fluid (pH 1.2) with 5.20 min buoyant lag-time. The in vitro drug release from these buoyant beads followed Korsmeyer-Peppas model (R(2)=0.9866-0.9995) with anomalous (non-Fickian) diffusion drug release mechanism. These new sterculia gum-alginate buoyant beads containing aceclofenac were also characterized using SEM, FTIR, and P-XRD analysis. PMID:23334180

  8. Carbopol 934-sodium alginate-gelatin mucoadhesive ondansetron tablets for buccal delivery: Effect of PH modifiers

    Directory of Open Access Journals (Sweden)

    Kotagale N

    2010-01-01

    Full Text Available The present work aims at developing mucoahesive tablets of ondansetron hydrochloride using bioadhesive polymers like carbopol-934, sodium alginate and gelatin. Tablets prepared by direct compression using different polymer with varying ratio were evaluated for hardness, friability, uniformity of weight, disintegration time, microenvironmental pH, bioadhesion and in vitro release. Hardness, friability disintegration time and drug release were found within pharmacopoeial limit. Microenvironmental pH decreased whereas bioadhesive strength, water uptake, and in vitro release increased with increase in carbopol-934. Increasing sodium alginate and gelatin increased the microenviromental pH and decreased bioadhesive strength, water uptake and in vitro release. With a view to investigate the modulation of drug release from formulation by addition of pH modifiers viz. citric acid and sodium bicarbonate, the tablets with carbopol-934 (2.0, sodium alginate (0.5 and gelatin (6.5 were used and the effect of pH modifiers on microenvironmental pH, bioadhesion, water uptake, in vitro permeation and in vitro release was studied. Microenvironmental pH, bioadhesive strength, water uptake, in vitro release and permeation decreased with increasing concentration of citric acid whereas microenvironmental pH, water uptake and release were enhanced and bioadhesive strength was lowered with increase in sodium bicarbonate. Present study demonstrates carbopol-934, sodium alginate, gelatin polymer system with added pH modifier can be successfully formulated for buccal delivery of ondansetron with desired release profile.

  9. Synthesis and antimicrobial activity of polysaccharide alginate derived cationic surfactant-metal(II) complexes.

    Science.gov (United States)

    Tawfik, Salah M; Hefni, Hassan H

    2016-01-01

    New natural polysaccharide carbohydrate derivatives of sodium alginate surfactant and its cobalt, copper and zinc complexes were synthesized. Structures of the synthesized compounds are reported using FTIR, (1)H NMR and UV-vis. The critical micelle concentration (CMC) value of the alginate surfactant and its metal complexes in aqueous solution was found out from surface tension measurements. Surface tension data at different temperatures served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔGmic, ΔHmic, ΔSmic) and adsorption (ΔGads, ΔGads, ΔSads). The surface activities of the synthesized polymeric surfactant and its metal complexes were influenced by their chemical structures and the type of the transition metals. These compounds were evaluated against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans and Asperigllus niger). The antibacterial and antifungal screening tests of the alginate surfactant metal complexes have shown good results compared to its precursor alginate surfactant. PMID:26478092

  10. Tissue responses against immunoisolating alginate-PLL capsules in the immediate posttransplant period

    NARCIS (Netherlands)

    de Vos, P; van Hoogmoed, CG; de Haan, BJ; Busscher, HJ

    2002-01-01

    Alginate-polylysine (PLL) capsules are commonly applied for immunoisolation of living cells for the treatment of a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules with failure of the grafts as a consequence. Mo

  11. Electrodeposition of alginate/chitosan layer-by-layer composite coatings on titanium substrates.

    Science.gov (United States)

    Wang, Zhiliang; Zhang, Xueqin; Gu, Juming; Yang, Haitao; Nie, Jun; Ma, Guiping

    2014-03-15

    In this study, alginate/chitosan layer-by-layer composite coatings were prepared on titanium substrates via electrodeposition. The mechanism of anodic deposition of anionic alginate based on the pH decrease at the anode surface, while the pH increase at the cathode surface enabled the deposition of cationic chitosan coatings. The surface of coatings was characterized by using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The properties of coatings were characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). Indirect in vitro cytotoxicity test showed that the extracts of coating had no significant effects on cell viability. Moreover, in vitro cytocompatibility test exhibited cell population and spreading tendency, suggesting that the coatings were non-toxic to L929 cells. However, the results revealed that alginate coating was more benefit for cells growing than chitosan coating. The results indicated that the proposed method could be used to fabricate alginate/chitosan layer-by-layer composite coatings on the titanium surface at room temperature and such composite coatings might have potential applications in tissue engineering scaffolds field. PMID:24528698

  12. Chitosan derivatives/reduced graphene oxide/alginate beads for small-molecule drug delivery.

    Science.gov (United States)

    Chen, Kaihang; Ling, Yunzhi; Cao, Cong; Li, Xiaoyun; Chen, Xiao; Wang, Xiaoying

    2016-12-01

    This work reported chitosan derivatives (CSD)/reduced graphene oxide (rGO) blending with alginate to prepare hydrogel beads for small-molecule drug delivery for the first time. At the beginning, graphene oxide (GO) was successfully reduced using diverse CSD as reducing and stabilizing agents via facile heating. Then the obtained CSD/rGO was blended with alginate and crosslinked into hydrogel beads in CaCl2 solution. Finally, the beads were systematically evaluated as novel vehicles for pH-responsive small-molecule drug delivery. The optimal CSD/rGO/alginate beads showed a high drug-loading efficiency of 82.8% on small-molecule fluorescein sodium (FL), outstanding sustainable release of 71.6% upon 150h at a physiological pH and quick-release of 82.4% drug content at 20h in an acidic medium. Additionally, the cytotoxicity assay result suggested that the CSD/rGO/alginate beads showed negligible cytotoxicity to hepatic stellate cell lines, opening up possibilities for safe and efficient drug delivery. PMID:27612820

  13. Biosorption of uranium by cross-linked and alginate immobilized residual biomass from distillery spent wash

    Energy Technology Data Exchange (ETDEWEB)

    Bustard, M. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine (United Kingdom); McHale, A.P. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine (United Kingdom)

    1997-08-01

    Residual biomass from a whiskey distillery was examined for its ability to function as a biosorbent for uranium. Biomass recovered and lyophilised exhibited a maximum biosorption capacity of 165-170 mg uranium/g dry weight biomass at 15 C. With a view towards the development of continuous or semi-continuous flow biosorption processes it was decided to immobilize the material by (1) cross-linking with formaldehyde and (2) introducing that material into alginate matrices. Cross-linking the recovered biomass resulted in the formation of a biosorbent preparation with a maximum biosorption capacity of 185-190 mg/g dry weight biomass at 15 C. Following immobilization of biomass in alginate matrices it was found that the total amount of uranium bound to the matrix did not change with increasing amounts of biomass immobilized. It was found however, that the proportion of uranium bound to the biomass within the alginate-biomass matrix increased with increasing biomass concentration. Further analysis of these preparations demonstrated that the alginate-biomass matrix had a maximum biosorption capacity of 220 mg uranium/g dry weight of the matrix, even at low concentrations of biomass. (orig.). With 3 figs., 1 tab.

  14. Numerical Modelling of Insulin and Amyloglucosidase Release from Swelling Ca-Alginate Beads

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Snabe, T.; Pedersen, Lars Haastrup

    2003-01-01

    The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes–Einstein...

  15. Piroxicam loaded alginate beads obtained by prilling/microwave tandem technique: morphology and drug release.

    Science.gov (United States)

    Aquino, Rita P; Auriemma, Giulia; d'Amore, Matteo; D'Ursi, Anna Maria; Mencherini, Teresa; Del Gaudio, Pasquale

    2012-07-01

    This paper presents a tandem technique, based on the combination of prilling and microwave (MW) assisted treatments, to produce biodegradable alginate carriers of piroxicam with different drug controlled release behaviours. Results showed that alginate/piroxicam beads demonstrated high encapsulation efficiency and very narrow dimensional distribution. Beads dried by MW retained shape and size distribution of the hydrated particles while drying rate was strongly increased compared to convective drying processes. Moreover, different MW irradiation regimes promoted interactions between the drug and alginate matrix, affected drug polymorphism as well as inner and surface matrix structure leading to different piroxicam release profiles. High level MW irradiation led to beads with highly porous and swellable matrix able to release piroxicam in few minutes in the intestine while convective drying produced gastro-resistant beads that exhibit sustained piroxicam release (total release in 5.5h) in intestinal environment. On these results the tandem technique prilling/MW irradiation appears to be promising to obtain alginate carrier with tailored NSAIDs release depending on drug characteristics and MW irradiation. PMID:24750857

  16. Enhancing the growth, photosynthetic capacity and artemisinin content in Artemisia annua L. by irradiated sodium alginate

    Energy Technology Data Exchange (ETDEWEB)

    Aftab, Tariq, E-mail: tarik.alig@gmail.co [Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh 202002 (India); Khan, M. Masroor A.; Idrees, M.; Naeem, M.; Moinuddin,; Hashmi, Nadeem [Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh 202002 (India); Varshney, Lalit [ISOMED, Radiation Technology Development Section, Radio-Chemistry and Isotope Group, BARC, Mumbai 400085 (India)

    2011-07-15

    Degrading the natural bioactive agents by ionizing radiation and then using them as growth promoting substances is a novel emerging technology to exploit the genetic potential of crops in terms of growth, yield and quality. Polysaccharides, such as sodium alginate, have proven to be wonderful growth promoting substances in their depolymerized form for various plants. The effect of depolymerized form of sodium alginate, produced by irradiating the latter by {sup 60}Co gamma rays, was studied on Artemisia annua L. with regard to growth attributes, physiological and biochemical parameters and artemisinin content. The study revealed that the irradiated sodium alginate (ISA), applied as leaf-sprays at a concentration of 20-120 mg L{sup -1}, improved the growth attributes, photosynthetic capability, enzyme activities and artemisinin content of the plant significantly. Application of ISA at 80 mg L{sup -1} increased the values of the attributes studied to the maximum extent. The enhancement of leaf-artemisinin content was ascribed to the ISA-enhanced H{sub 2}O{sub 2} content in the leaves. -- Highlights: {yields} Application of ionizing radiation to degrade natural bioactive agents is a novel emerging technology. {yields} Sodium alginate has been used as the growth promoting substance in its depolymerized form for various plants. {yields} The study revealed that irradiated sodium algiante at 20-120 ppm concentration improved the plant growth. {yields} The enhancement of artemisinin content was ascribed to the ISA-enhanced H{sub 2}O{sub 2} content in leaves.

  17. The effect of calcium chloride concentration on alginate/Fmoc-diphenylalanine hydrogel networks.

    Science.gov (United States)

    Çelik, Ekin; Bayram, Cem; Akçapınar, Rümeysa; Türk, Mustafa; Denkbaş, Emir Baki

    2016-09-01

    Peptide based hydrogels gained a vast interest in the tissue engineering studies thanks to great superiorities such as biocompatibility, supramolecular organization without any need of additional crosslinker, injectability and tunable nature. Fmoc-diphenylalanine (FmocFF) is one of the earliest and widely used example of these small molecule gelators that have been utilized in biomedical studies. However, Fmoc-peptides are not feasible for long term use due to low stability and weak mechanical properties at neutral pH. In this study, Fmoc-FF dipeptides were mechanically enhanced by incorporation of alginate, a biocompatible and absorbable polysaccharide. The binary hydrogel is obtained via molecular self-assembly of FmocFF dipeptide in alginate solution followed by ionic crosslinking of alginate moieties with varying concentrations of calcium chloride. Hydrogel characterization was evaluated in terms of morphology, viscoelastic moduli and diffusional phenomena and the structures were tested as 3D scaffolds for bovine chondrocytes. In vitro evaluation of scaffolds lasted up to 14days and cell viability, sulphated glycosaminoglycan (sGAG) levels, collagen type II synthesis were determined. Our results showed that alginate incorporation into FmocFF hydrogels leads to better mechanical properties and higher stability with good biocompatibility. PMID:27207058

  18. Human adipose-derived stromal cells in a clinically applicable injectable alginate hydrogel

    DEFF Research Database (Denmark)

    Larsen, Bjarke Follin; Juhl, Morten; Cohen, Smadar;

    2015-01-01

    BACKGROUND AIMS: Clinical trials have documented beneficial effects of mesenchymal stromal cells from bone marrow and adipose tissue (ASCs) as treatment in patients with ischemic heart disease. However, retention of transplanted cells is poor. One potential way to increase cell retention is to in...... and alginate is non-immunogenic and, in fact, immunosuppressive....

  19. Impact of solvent quality on the network strength and structure of alginate gels.

    Science.gov (United States)

    Hermansson, Elin; Schuster, Erich; Lindgren, Lars; Altskär, Annika; Ström, Anna

    2016-06-25

    The influence of the mixture of water and alcohols on the solubility and properties of alginate and its calcium-induced gels is of interest for the food, wound care and pharmaceutical industries. The solvent quality of water with increasing amounts of ethanol (0-20%) on alginate was studied using intrinsic viscosity. The effect of ethanol addition on the rheological and mechanical properties of calcium alginate gels was determined. Small-angle X-ray scattering and transmission electron microscopy were used to study the network structure. It is shown that the addition of ethanol up to 15% (wt) increases the extension of the alginate chain, which correlates with increased moduli and stress being required to fracture the gels. The extension of the polymer chain is reduced at 20% (wt) ethanol, which is followed by reduced moduli and stress at breakage of the gels. The network structure of gels at high ethanol concentrations (24%) is characterized by thick and poorly connected network strands. PMID:27083820

  20. PREPARATION AND CHARACTERIZATION OF CINNARIZINE FLOATING OIL ENTRAPPED CALCIUM ALGINATE BEADS

    Directory of Open Access Journals (Sweden)

    Mowafaq M. Ghareeb et al.

    2012-02-01

    Full Text Available Gastroretentive delivery systems can be retained in the stomach and assist in improving absorption and consequently the bioavailability of drug that has a narrow absorption window in a particular region of gastrointestinal tract. A floatable multiparticulate system with potential for intragastric sustained delivery is one of the approaches to get the gastroretention. Cinnarizine(CNZ, an antihistaminic drug used in vertigo caused by meniere’s disease was taken as a model drug for floating beads prepared by non effervescent method. Floating CNZ olive oil-entrapped emulsion gel beads were prepared by the emulsion–gelation method. Different concentrations of sodium alginate (1%, 2%, and 3% w/v, oil (5%, 10%, and 15% v/v, and calcium chloride (0.02, 0.1, and 0.5M were used and their influence on beads uniformity, buoyancy, and in vitro drug release was studied. The results indicated that retardation of drug release was achieved by the oil hydrophobic diffusion barrier, especially in the presence of the compact network of alginate beads. The selected formula of calcium alginate beads using 3% w/v sodium alginate, 15% v/v oil and 0.1 M calcium chloride, showed a higher similarity factor (f2 =70.1 of CNZ release in comparison to release from standard gastroretentive sustained release floating cinnarizine tablet with good floating over duration of more than 12 hours.

  1. Composite Films from Sodium Alginate and High Methoxyl Pectin - Physicochemical Properties and Biodegradation in Soil

    Directory of Open Access Journals (Sweden)

    Ayten O. Solak

    2014-12-01

    Full Text Available The increased public attention on the waste pollution and the awareness of the hard environmental problems is the reason for the need of new materials which are susceptible to degradation in nature for a short period of time. The biopolymer films and coatings based on renewable natural sources are suitable for obtaining of biodegradable packaging. The newly developed composite films based on sodium alginate and apple high methoxyl pectin were studied for total soluble matter, swelling in water, water vapors transmission rate and biodegradation in soil. The analysis of their behavior in water medium showed a considerably higher rate and degree of dissolution of the pectin monocomponent film compared to the composite and alginate films. The composite alginate-pectin films showed lower water vapors transmission rate even under extreme conditions (38ºC, RH 90 % compared to the monocomponent films. All investigated films degraded in soil up to 80 days. The good barrier properties to water vapors and the complete biodegradation in soil make the films based on sodium alginate and high methoxyl pectin potential ecological materials for packing and coating of foods and pharmaceutical products.

  2. Sorption of Sr-85 and Am-241 from liquid radioactive wastes by alginate beads

    Directory of Open Access Journals (Sweden)

    Oszczak Agata

    2015-12-01

    Full Text Available The paper reports the adsorption of strontium(II and americium(III from aqueous solutions onto calcium alginate (CaA, barium alginate (BaA and strontium alginate (SrA beads. Adsorption process was studied in batch experiments as a function of the initial pH of the solution and the contact time. All sorbents were examined by the termogravimetric analysis (TG. Laboratory obtained spherical beads of CaA, BaA and SrA seem to be good metal sorbents from liquid radioactive wastes. A contact time of about 4 h and neutral pH of the initial aqueous solution have been proposed to be optimum conditions for Sr-85 and Am-241 removal from the contaminated solutions using alginate sorbents. Laboratory obtained beads of CaA, BaA and SrA are characterized by the decontamination factor (DF equal to 85% for Sr(II and 90% for Am(III.

  3. Effect of microcavitary alginate hydrogel with different pore sizes on chondrocyte culture for cartilage tissue engineering

    International Nuclear Information System (INIS)

    In our previous work, a novel microcavitary hydrogel was proven to be effective for proliferation of chondrocytes and maintenance of chondrocytic phenotype. In present work, we further investigated whether the size of microcavity would affect the growth and the function of chondrocytes. By changing the stirring rate, gelatin microspheres in different sizes including small size (80–120 μm), middle size (150–200 μm) and large size (250–300 μm) were prepared. And then porcine chondrocytes were encapsulated into alginate hydrogel with various sizes of gelatin microspheres. Cell Counting Kit-8 (CCK-8), Live/dead staining and real-time PCR were used to analyze the effect of the pore size on cell proliferation and expression of specific chondrocytic genes. According to all the data, cells cultivated in microcavitary hydrogel, especially in small size, had preferable abilities of proliferation and higher expression of cartilaginous markers including type II collagen, aggrecan and cartilage oligomeric matrix protein (COMP). Furthermore, it was shown by western blot assay that the culture of chondrocytes in microcavitary hydrogel could improve the proliferation of cells potentially by inducing the Erk1/2-MAPK pathway. Taken together, this study demonstrated that chondrocytes favored microcavitary alginate hydrogel with pore size within the range of 80–120 μm for better growth and ECM synthesis, in which Erk1/2 pathway was involved. This culture system would be promising for cartilage tissue engineering. - Highlights: • A novel model with microcavitary structure was set up to study the interaction between cells and materials. • Microcavitary alginate hydrogel could enhance the proliferation of chondrocytes and promote the expression of cartilaginous genes as compared with plain alginate hydrogel. • Cells in microcavitary alginate hydrogel with pore size within the range of 80–120 μm were capable of better growth and ECM synthesis

  4. Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae.

    Science.gov (United States)

    Laue, Heike; Schenk, Alexander; Li, Hongqiao; Lambertsen, Lotte; Neu, Thomas R; Molin, Søren; Ullrich, Matthias S

    2006-10-01

    Exopolysaccharides (EPSs) play important roles in the attachment of bacterial cells to a surface and/or in building and maintaining the three-dimensional, complex structure of bacterial biofilms. To elucidate the spatial distribution and function of the EPSs levan and alginate during biofilm formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser scanning microscopy with fluorescently labelled lectins was applied to investigate the spatial distribution of levan and an additional as yet unknown EPS in flow-chamber biofilms. Concanavalin A (ConA) bound specifically to levan and accumulated in cell-depleted voids in the centres of microcolonies and in blebs. No binding of ConA was observed in biofilms of the levan-deficient mutants or in wild-type biofilms grown in the absence of sucrose as confirmed by an enzyme-linked lectin-sorbent assay using peroxidase-linked ConA. Time-course studies revealed that expression of the levan-forming enzyme, levansucrase, occurred mainly during early exponential growth of both planktonic and sessile cells. Thus, accumulation of levan in biofilm voids hints to a function as a nutrient storage source for later stages of biofilm development. The presence of a third EPS besides levan and alginate was indicated by binding of the lectin from Naja mossambica to a fibrous structure in biofilms of all P. syringae derivatives. Production of the as yet uncharacterized additional EPS might be more important for biofilm formation than the syntheses of levan and alginate. PMID:17005972

  5. Immunological and technical considerations in application of alginate-based microencapsulation systems

    Directory of Open Access Journals (Sweden)

    Genaro Alberto Paredes Juárez

    2014-08-01

    Full Text Available Islets encapsulated in immunoprotective microcapsules are being proposed as an alternative for insulin therapy for treatment of type 1 diabetes. Many materials for producing microcapsules have been proposed but only alginate does currently qualify as ready for clinical application. However, many different alginate-based capsule systems do exist. A pitfall in the field is that these systems are applied without a targeted strategy with varying degrees of success as a consequence. In the current review the different properties of alginate-based systems are reviewed in view of future application in humans. The use of allogeneic and xenogeneic islet sources are discussed with acknowledging the different degrees of immune protection the encapsulation system should supply. Also issues such as oxygen supply and the role of danger associated molecular patterns (DAMPS in immune activation are being reviewed.A common property of the encapsulation systems is that alginates for medical application should have an extreme high degree of purity and lack pathogen-associated molecular patterns (PAMPs to avoid activation of the recipient’s immune system. Up to now, non-inflammatory alginates are only produced on a lab-scale and are not yet commercially available. This is a major pitfall on the route to human application. Also the lack of predictive pre-clinical models is a burden. The principle differences between relevant innate and adaptive immune responses in humans and other species are reviewed. Especially the extreme differences between the immune system of non-human primates and humans are cumbersome as non-human primates may not be predictive of the immune responses in humans, as opposed to the popular belief of regulatory agencies. Current insight is that although the technology is versatile major research efforts are required for identifying the mechanical, immunological and physico-chemical requirements for successful human application.

  6. Biological deterioration of alginate beads containing immobilized microalgae and bacteria during tertiary wastewater treatment.

    Science.gov (United States)

    Cruz, Ivonne; Bashan, Yoav; Hernàndez-Carmona, Gustavo; de-Bashan, Luz E

    2013-11-01

    Secondary treatment of municipal wastewater affects the mechanical stability of polymer Ca-alginate beads containing the microalgae Chlorella vulgaris that are jointly immobilized with Azospirillum brasilense as treating agents whose presence do not affect bead stability. Nine strains of potential alginate-degrading bacteria were isolated from wastewater and identified, based on their nearly complete 16S rDNA sequence. Still, their population was relatively low. Attempts to enhance the strength of the beads, using different concentrations of alginate and CaCl2 or addition of either of three polymers (polyvinylpyrrolidone, polyvinyl alcohol, carboxymethylcellulose), CaCO3, or SrCl2, failed. Beads lost their mechanical strength after 24 h of incubation but not the integrity of their shape for at least 96 h, a fact that sustained successful tertiary wastewater treatment for 48 h. In small bioreactors, removal of phosphorus was low under sterile conditions but high in unsterile wastewater. Alginate beads did not absorb PO4 (-3) in sterile wastewater, but in natural wastewater, they contained PO4 (-3). Consequently, PO4 (-3) content declined in the wastewater. A supplement of 10 % beads (w/v) was significantly more efficient in removing nutrients than 4 %, especially in a jointly immobilized treatment where >90 % of PO4 (-3) and >50 % ammonium were removed. Tertiary wastewater treatment in 25-L triangular, airlift, autotrophic bioreactors showed, as in small bioreactors, very similar nutrient removal patterns, decline in bead strength phenomena, and increase in total bacteria during the wastewater treatment only in the presence of the immobilized treatment agents. This study demonstrates that partial biological degradation of alginate beads occurred during tertiary wastewater treatment, but the beads survive long enough to permit efficient nutrient removal. PMID:23354446

  7. Quantitative analysis of potentially toxic metals in alginates for dental use

    Directory of Open Access Journals (Sweden)

    A. S. BRAGA

    2009-01-01

    Full Text Available

    Alginate is one the materials most employed in practice to make dental impressions. Substances like zinc, cadmium and lead silicate, which are included in several alginate brands with the aim of improving their physical, chemical and mechanical properties, are a source of serious concern as regards their toxicity. The most serious chronic effect of oral exposure to cadmium is renal toxicity. Assimilation of lead has deleterious effects on the gastrointestinal tract, hematopoietic system, cardiovascular system, central and peripheral nervous systems, kidneys, immune system, and reproductive system. Chronic oral exposures to zinc have resulted in hypochromic and microcyte anemia in some individuals. The aim of the present study was to measure the cadmium, lead and zinc contents of seven brands of alginate for dental use on sale in Brazil. The samples were weighed and placed in the Teflon cups of a closedsystem microwave oven. Aqua regia (4mL concentrated HCl:HNO3, 3:1 v/v and hydrofluoric acid (2mL concentrated HF were added to the samples, which were then subjected to heating. The samples were then cooled to room temperature and diluted to 25 mL in deionized water in a volumetric glass flask. The samples were diluted in duplicate and analyzed against a reagent blank. The analyses were performed in an atomic absorption flame spectrophotometer. Neither lead nor cadmium was detected. Zinc contents ranged from 0.001% to 1.36% by weight. The alginates exhibited low contents of the metals under study and gave no cause for concern regarding toxicity; even so, it is advisable to monitor potentially toxic materials continually and to analyze their plasmatic levels in the professionals working with them. Keywords: Cadmium, lead, zinc, alginates, intoxication, irreversible hydrocolloid.

  8. Applicability of sodium alginate in decorporation therapy of strontium radioisotopes in human being

    International Nuclear Information System (INIS)

    The increasing release of fission products from nuclear weapon tests in the environment has been rising the levels of radioactive contamination of food chains caused by the fall-out of these elements. In cases of accidental exposure, human subjects could be submitted to an internal contamination, which is likely to include several radionuclides. Special concern must be given, however, to the radioactive isotopes of strontium, cesium and iodine, along with the highly radio toxic transuranium elements like cerium. It was found that sodium alginate, a polyelectrolyte commonly used in food industry and obtained from brown algae (Phaeophyceae), provides the selective suppression of absorption of radioactive strontium presented in the ingested food material with no disturbance of the electrolyte balance nor undesirable side effects, even for a long term treatment. Moreover, these patterns were maintained when alginate was associated to other decontamination additives, specially those related to the other radioisotopes mentioned above, as, in this case, losses in the effectiveness, mutual interference or adverse health effects were not detected. These conclusions ground the discussion about the present trend in the usual choice of EDTA/DTPA complex therapy rather than of alginate therapy for medical assistance of radiocontaminated patients, although they corroborate the efficiency and usefulness of alginate salts in situations related to extensive intakes of strontium radioisotopes alone or associated to other fission products. The purpose of the present work is to make a general review of the alginate therapy as well as to discuss its present and future therapeutic importance from the scientific and institutional points of view. (author)

  9. Assessment of molecular events during in vitro re-epithelialization under honey-alginate matrix ambience

    International Nuclear Information System (INIS)

    Re-epithelialization is one of the most important stages of cutaneous regeneration and its success requires supportive micro-ambience which may be provided with suitable bio-matrix. Biocompatibility and efficacy of such bio-matrix in re-epithelialization could be explored by multimodal analysis of structural and functional attributes of in vitro wound healing model including evaluation of prime molecular expressions of the epithelial cells during repair. Present study examines the influence of honey-alginate and alginate matrices on re-epithelialization in keratinocyte (HaCaT) population in a 2-D wound model. Cellular viability, proliferation and cell–cell adhesion status were assessed during wound closure using live/dead cell assay and by evaluating expressions of Ki67, p63 and E-cadherin along-with % change in cellular electrical impedance. Efficacy of honey-alginate matrix in comparison to only alginate one was demonstrated by a quicker reduction in wound gap, improved cellular viability, enhanced expressions of Ki67, p63 and its isoforms (TAp63, ΔNp63) as well as E-cadherin. Faster restoration of electrical attribute (% of impedance change) after wounding also indicated better impact of honey-alginate matrix in re-epithelialization. - Highlights: • Role of honey based matrix is evaluated in wound re-epithelialization. • Healing impact of matrix studied in 2D in vitro keratinocyte (HaCaT) wound model. • Faster impedance restoration indicated rapid healing rate of HaCaT under honey. • PCR observations showed faster initiation of cell proliferation under honey. • ICC study indicated better up-regulation of healing markers under honey matrix

  10. Assessment of molecular events during in vitro re-epithelialization under honey-alginate matrix ambience

    Energy Technology Data Exchange (ETDEWEB)

    Barui, Ananya [Centre for Healthcare Science and Technology, BESU, Shibpur, Howrah 711103, West Bengal (India); Mandal, Naresh [Dept. of Electronics and Telecommunication Engg., BESU, Shibpur, Howrah 711103, West Bengal (India); Majumder, Subhadipa [Department of Biochemistry, University of Calcutta Ballygunge, Circular Road, Kolkata 700 019, West Bengal (India); Das, Raunak Kumar [School of Medical Science and Technology, IIT, Kharagpur 721 302, West Bengal (India); Sengupta, Sanghamitra [Department of Biochemistry, University of Calcutta Ballygunge, Circular Road, Kolkata 700 019, West Bengal (India); Banerjee, Provas [School of Medical Science and Technology, IIT, Kharagpur 721 302, West Bengal (India); Ray, Ajoy Kumar; RoyChaudhuri, Chirosree [Dept. of Electronics and Telecommunication Engg., BESU, Shibpur, Howrah 711103, West Bengal (India); Chatterjee, Jyotirmoy, E-mail: jchatterjee@smst.iitkgp.ernet.in [School of Medical Science and Technology, IIT, Kharagpur 721 302, West Bengal (India)

    2013-08-01

    Re-epithelialization is one of the most important stages of cutaneous regeneration and its success requires supportive micro-ambience which may be provided with suitable bio-matrix. Biocompatibility and efficacy of such bio-matrix in re-epithelialization could be explored by multimodal analysis of structural and functional attributes of in vitro wound healing model including evaluation of prime molecular expressions of the epithelial cells during repair. Present study examines the influence of honey-alginate and alginate matrices on re-epithelialization in keratinocyte (HaCaT) population in a 2-D wound model. Cellular viability, proliferation and cell–cell adhesion status were assessed during wound closure using live/dead cell assay and by evaluating expressions of Ki67, p63 and E-cadherin along-with % change in cellular electrical impedance. Efficacy of honey-alginate matrix in comparison to only alginate one was demonstrated by a quicker reduction in wound gap, improved cellular viability, enhanced expressions of Ki67, p63 and its isoforms (TAp63, ΔNp63) as well as E-cadherin. Faster restoration of electrical attribute (% of impedance change) after wounding also indicated better impact of honey-alginate matrix in re-epithelialization. - Highlights: • Role of honey based matrix is evaluated in wound re-epithelialization. • Healing impact of matrix studied in 2D in vitro keratinocyte (HaCaT) wound model. • Faster impedance restoration indicated rapid healing rate of HaCaT under honey. • PCR observations showed faster initiation of cell proliferation under honey. • ICC study indicated better up-regulation of healing markers under honey matrix.

  11. Effect of microcavitary alginate hydrogel with different pore sizes on chondrocyte culture for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Lei; Yao, Yongchang [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Wang, Dong-an, E-mail: DAWang@ntu.edu.sg [National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Chen, Xiaofeng, E-mail: chenxf@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China)

    2014-01-01

    In our previous work, a novel microcavitary hydrogel was proven to be effective for proliferation of chondrocytes and maintenance of chondrocytic phenotype. In present work, we further investigated whether the size of microcavity would affect the growth and the function of chondrocytes. By changing the stirring rate, gelatin microspheres in different sizes including small size (80–120 μm), middle size (150–200 μm) and large size (250–300 μm) were prepared. And then porcine chondrocytes were encapsulated into alginate hydrogel with various sizes of gelatin microspheres. Cell Counting Kit-8 (CCK-8), Live/dead staining and real-time PCR were used to analyze the effect of the pore size on cell proliferation and expression of specific chondrocytic genes. According to all the data, cells cultivated in microcavitary hydrogel, especially in small size, had preferable abilities of proliferation and higher expression of cartilaginous markers including type II collagen, aggrecan and cartilage oligomeric matrix protein (COMP). Furthermore, it was shown by western blot assay that the culture of chondrocytes in microcavitary hydrogel could improve the proliferation of cells potentially by inducing the Erk1/2-MAPK pathway. Taken together, this study demonstrated that chondrocytes favored microcavitary alginate hydrogel with pore size within the range of 80–120 μm for better growth and ECM synthesis, in which Erk1/2 pathway was involved. This culture system would be promising for cartilage tissue engineering. - Highlights: • A novel model with microcavitary structure was set up to study the interaction between cells and materials. • Microcavitary alginate hydrogel could enhance the proliferation of chondrocytes and promote the expression of cartilaginous genes as compared with plain alginate hydrogel. • Cells in microcavitary alginate hydrogel with pore size within the range of 80–120 μm were capable of better growth and ECM synthesis.

  12. Electro-spray of high viscous liquids for producing mono-sized spherical alginate beads

    Institute of Scientific and Technical Information of China (English)

    Hamid Moghadam; Mohsen Samimi; Abdolreza Samimi; Mohamad Khorram

    2008-01-01

    Alginate beads, often used for controlled release of enzymes and drugs, are usually produced by spraying sodium alginate liquid into a gelling agent using mechanical vibration nozzle or air jet. In this work an alternative method of electro-spray was employed to form droplets with desired size from a highly viscous sodium alginate solution using constant DC voltage. The droplets were then cured in a calcium chloride solution. The main objective was to produce mono-sized beads from such a highly viscous and non-Newtonian liquid (1000-5000 mPa s). The effects of nozzle diameter, flow rate and concentration of liquid on the size of the beads were investigated. Among the parameters studied, voltage had a pronounced effect on the size of beads as compared to flow rate zzle diameter and concentration of alginate liquid. The size of beads was reduced to a minimum value with increasing the voltage in the range of 0-10 kV. At the early stages of voltage increase (I.e. Up to about 4 kV), the rate of size reduction was relatively low, while the dripping mode dominated. However, in the middle part of the range of applied voltage, where the rate of size reduction was high (I.e. About 4-7 kV), an unstable transition occurred between dripping and jetting. At the end part of the range (I.e. 7-10 kV) jet mode of spray was observed. Increasing the height of fall of the droplets was found to improve the sphericity of the beads, because of the increased time of flight for the droplets. This was especially identifiable at higher concentrations of the alginate liquid (I.e. 3 w/v%)

  13. Fabrication of highly porous keratin sponges by freeze-drying in the presence of calcium alginate beads

    International Nuclear Information System (INIS)

    Novel fabrication method of highly porous and flexible keratin sponges was developed by combining a particulate-leaching method and a freeze-drying method. Reduced keratin aqueous solution was mixed with dried calcium alginate beads and was lyophilized to give keratin/calcium alginate complex, which was subsequently treated with EDTA solution to leach out calcium alginate beads. The resultant keratin sponge was flexible enough to handle even in dried state because of its quite high porosity (98.9 ± 0.1%), which was brought about by the large and small pores formed by the elimination of calcium alginate beads and water. The sponge supported the attachment and the proliferation of mouse fibroblast cells. Thus, the keratin sponge given by the present fabrication method afforded one alternative as a cell scaffold for tissue engineering

  14. In situ Gelation of Monodisperse Alginate Hydrogel in Microfluidic Channel Based on Mass Transfer of Calcium Ions

    International Nuclear Information System (INIS)

    A microfluidic method for the in situ production of monodispersed alginate hydrogels using biocompatible polymer gelation by crosslinker mass transfer is described. Gelation of the hydrogel was achieved in situ by the dispersed calcium ion in the microfluidic device. The capillary number (Ca) and the flow rate of the disperse phase which are important operating parameters mainly influenced the formation of three distinctive flow regions, such as dripping, jetting, and unstable dripping. Under the formation of dripping region, monodispersed alginate hydrogels having a narrow size distribution (C.V=2.71%) were produced in the microfluidic device and the size of the hydrogels, ranging from 30 to 60 µm, could be easily controlled by varying the flow rate, viscosity, and interfacial tension. This simple microfluidic method for the production of monodisperse alginate hydrogels shows strong potential for use in delivery systems of foods, cosmetics, inks, and drugs, and spherical alginate hydrogels which have biocompatibility will be applied to cell transplantation

  15. Immobilization of Lipase using Alginate Hydrogel Beads and Enzymatic Evaluation in Hydrolysis of p-Nitrophenol Butyrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuang; Shang, Wenting; Yang, Xiaoxi; Zhang, Shujuan; Zhang, Xiaogang; Chen, Jiawei [Renmin Univ. of China, Beijing (China)

    2013-09-15

    The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.

  16. In situ Gelation of Monodisperse Alginate Hydrogel in Microfluidic Channel Based on Mass Transfer of Calcium Ions

    Energy Technology Data Exchange (ETDEWEB)

    Song, YoungShin; Lee, Chang-Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2014-10-15

    A microfluidic method for the in situ production of monodispersed alginate hydrogels using biocompatible polymer gelation by crosslinker mass transfer is described. Gelation of the hydrogel was achieved in situ by the dispersed calcium ion in the microfluidic device. The capillary number (Ca) and the flow rate of the disperse phase which are important operating parameters mainly influenced the formation of three distinctive flow regions, such as dripping, jetting, and unstable dripping. Under the formation of dripping region, monodispersed alginate hydrogels having a narrow size distribution (C.V=2.71%) were produced in the microfluidic device and the size of the hydrogels, ranging from 30 to 60 µm, could be easily controlled by varying the flow rate, viscosity, and interfacial tension. This simple microfluidic method for the production of monodisperse alginate hydrogels shows strong potential for use in delivery systems of foods, cosmetics, inks, and drugs, and spherical alginate hydrogels which have biocompatibility will be applied to cell transplantation.

  17. In vitro release modulation from crosslinked pellets for site-specific drug delivery to the gastrointestinal tract. II. Physicochemical characterization of calcium-alginate, calcium-pectinate and calcium-alginate-pectinate pellets.

    Science.gov (United States)

    Pillay, V; Fassihi, R

    1999-05-20

    Pellets of calcium-alginate, calcium-pectinate and calcium-alginate-pectinate were produced via crosslinking in an aqueous medium for site-specific drug delivery in the gastrointestinal tract. A comparative study of their physicochemical characteristics by means of texture analysis, modulated temperature differential scanning calorimetry (MTDSC), scanning electron microscopy and swelling dynamics under different pH conditions was undertaken. It was found that the incorporation of low methoxylated pectin (i.e., degree of methoxylation approximately 35%) together with alginate appears to influence the degree of crosslinking and subsequently the physical, mechanical and resilience behavior. In general, texture analysis of various pellets indicated that both strength and resilience profiles were in the order of calcium-alginate>/=calcium-alginate-pectinate>calcium-pectinate. Calcium-alginate pellets were found to be viscoelastic, while calcium-pectinate was highly brittle. Through the application of MTDSC, depolymerization transitions, reversing and non-reversing heat flow were determined and interpreted for each formulation. Scanning electron microscopy and micro-thermal analysis revealed distinct morphological differences in each case. The influence of and nature of crosslinking, and textural properties of such pellets on drug release rate modulation is discussed. PMID:10332058

  18. Fructose 1,6-bisphosphate aldolase activity is essential for synthesis of alginate from glucose by Pseudomonas aeruginosa.

    OpenAIRE

    Banerjee, P C; Vanags, R I; Chakrabarty, A M; Maitra, P. K.

    1985-01-01

    We have isolated a mutant of Pseudomonas aeruginosa deficient in fructose 1,6-bisphosphate aldolase activity. This mutant, similar to the mutants deficient in any of the Entner-Doudoroff pathway enzymes, does not allow appreciable alginate formation from glucose and gluconate, but allows alginate synthesis from mannitol and fructose. This suggests that glucose and gluconate must be converted to fructose 1,6-bisphosphate via the Entner-Doudoroff pathway enzymes and fructose 1,6-bisphosphate al...

  19. Alginate is not a significant component of the extracellular polysaccharide matrix of PA14 and PAO1 Pseudomonas aeruginosa biofilms

    OpenAIRE

    Wozniak, Daniel J.; Wyckoff, Timna J. O.; Starkey, Melissa; Keyser, Rebecca; Azadi, Parastoo; O'Toole, George A.; Parsek, Matthew R.

    2003-01-01

    The bacterium Pseudomonas aeruginosa causes chronic respiratory infections in cystic fibrosis (CF) patients. Such infections are extremely difficult to control because the bacteria exhibit a biofilm-mode of growth, rendering P. aeruginosa resistant to antibiotics and phagocytic cells. During the course of infection, P. aeruginosa usually undergoes a phenotypic switch to a mucoid colony, which is characterized by the overproduction of the exopolysaccharide alginate. Alginate overproducti...

  20. The promotion of in vitro vessel-like organization of endothelial cells in magnetically responsive alginate scaffolds

    OpenAIRE

    Sapir, Yulia; Cohen, Smadar; Friedman, Gary; Polyak, Boris

    2012-01-01

    One of the major challenges in engineering thick, complex tissues such as cardiac muscle, is the need to pre-vascularize the engineered tissue in vitro to enable its efficient integration with host tissue upon implantation. Herein, we explored new magnetic alginate composite scaffolds to provide means of physical stimulation to cells. Magnetite-impregnated alginate scaffolds seeded with aortic endothelial cells stimulated during the first 7 days out of a total 14 day experimental course showe...

  1. Effect of Alginate on Satiation, Appetite, Gastric Function and Selected Gut Satiety Hormones in Overweight and Obesity

    OpenAIRE

    Odunsi, Suwebatu T.; Vázquez Roque, María I.; Camilleri, Michael; Papathanasopoulos, Athanasios; Clark, Matthew M.; Wodrich, Lynne; Lempke, Mary; McKinzie, Sanna; RYKS, MICHAEL; Burton, Duane; Zinsmeister, Alan R.

    2009-01-01

    Lack of control of food intake, excess size and frequency of meals are critical in to the development of obesity. The stomach signals satiation postprandially and may play an important role in control of calorie intake. Sodium alginate (based on brown seaweed Laminaria Digitata) is currently marketed as a weight loss supplement, but its effects on gastric motor functions and satiation are unknown. We evaluated effects of 10 days treatment with alginate or placebo on gastric functions, satiati...

  2. Development of a cell culture surface conversion technique using alginate thin film for evaluating effect upon cellular differentiation

    International Nuclear Information System (INIS)

    Here, we sought to develop a cell culture surface conversion technique that would not damage living cells. An alginate thin film, formed on a glass plate by spin coating of sodium alginate solution and dipping into calcium chloride solution, was used to inhibit adhesion of cells. The film could be removed by ethylenediaminetetraacetate (EDTA) at any time during cell culture, permitting observation of cellular responses to conversion of the culture surface in real time. Additionally, we demonstrated the validity of the alginate thin film coating method and the performance of the film. The thickness of the alginate thin film was controlled by varying the rotation speed during spin coating. Moreover, the alginate thin film completely inhibited the adhesion of cultured cells to the culture surface, irrespective of the thickness of the film. When the alginate thin film was removed from the culture surface by EDTA, the cultured cells adhered to the culture surface, and their morphology changed. Finally, we achieved effective differentiation of C2C12 myoblasts into myotube cells by cell culture on the convertible culture surface, demonstrating the utility of our novel technique

  3. Cetylpyridinium chloride/magnetic alginate beads: an efficient system to remove p-nitrophenol from wastewater

    Science.gov (United States)

    Obeid, Layaly; Bee, Agnes; Talbot, Delphine; Abramson, Sebastien; Welschbillig, Mathias

    2014-05-01

    The adsorption process is one of the most efficient methods to remove pollutants from wastewater provided that suitable adsorbents are used. In order to produce environmentally safe adsorbents, natural polymers have received increasing attention in recent years. Thus, alginate, a polysaccharide extracted from brown seaweeds, is extensively used as inexpensive, non-toxic and efficient biosorbent. Furthermore, it has been shown that the encapsulation of magnetic materials in alginate beads facilitates their recovery from wastewater after the adsorption step, by the use of an external magnetic field gradient, obtained with a magnet or an electromagnet [1, 2]. In the present work, we have studied the adsorption affinity of magnetic alginate beads (called magsorbents)for p-nitrophenol (PNP), used as a hydrophobic pollutant, in presence of cetylpyridinium chloride (CPC), a cationic surfactant. First, the effect of different parameters (pH solution, contact time, surfactant initial concentration…) on the adsorption of CPC on the alginate beads was investigated. Adsorption of the surfactant occurs due to electrostatic attractions between its cationic head groups and negative carboxylate functions of the alginate beads. At larger surfactant concentrations, adsorption is also due to the interaction between the hydrocarbon chains of CPC forming aggregated structures capable of solubilizing hydrophobic solutes. In a second step, we showed that PNP can reach up to 95% of adsorption in the beads in presence of CPC, although the pollutant is poorly adsorbed by alginate in absence of the surfactant. At highest CPC concentrations, desorption occurs as micellar solubilization is preferred over coadsorption. Our magsorbents appear to efficiently remove both cationic surfactant and hydrophobic pollutants and we hope that this fundamental research will be helpful for the future development of magnetically assisted processes in water treatment plants. 1. A.Bee, D.Talbot, S.Abramson, V

  4. Immobilization of Brassica oleracea Chlorophyllase 1 (BoCLH1 and Candida rugosa Lipase (CRL in Magnetic Alginate Beads: An Enzymatic Evaluation in the Corresponding Proteins

    Directory of Open Access Journals (Sweden)

    Chih-Hui Yang

    2014-08-01

    Full Text Available Enzymes have a wide variety of applications in diverse biotechnological fields, and the immobilization of enzymes plays a key role in academic research or industrialization due to the stabilization and recyclability it confers. In this study, we immobilized the Brassica oleracea chlorophyllase 1 (BoCLH1 or Candida rugosa lipase (CRL in magnetic iron oxide nanoparticles-loaded alginate composite beads. The catalytic activity and specific activity of the BoCLH1 and CRL entrapped in magnetic alginate composite beads were evaluated. Results show that the activity of immobilized BoCLH1 in magnetic alginate composite beads (3.36 ± 0.469 U/g gel was higher than that of immobilized BoCLH1 in alginate beads (2.96 ± 0.264 U/g gel. In addition, the specific activity of BoCLH1 beads (10.90 ± 1.521 U/mg protein was higher than that immobilized BoCLH1 in alginate beads (8.52 ± 0.758 U/mg protein. In contrast, the immobilized CRL in magnetic alginate composite beads exhibited a lower enzyme activity (11.81 ± 0.618 than CRL immobilized in alginate beads (94.83 ± 7.929, and the specific activity of immobilized CRL entrapped in magnetic alginate composite beads (1.99 ± 0.104 was lower than immobilized lipase in alginate beads (15.01 ± 1.255. A study of the degradation of magnetic alginate composite beads immersed in acidic solution (pH 3 shows that the magnetic alginate composite beads remain intact in acidic solution for at least 6 h, indicating the maintenance of the enzyme catalytic effect in low-pH environment. Finally, the enzyme immobilized magnetic alginate composite beads could be collected by an external magnet and reused for at least six cycles.

  5. Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation

    DEFF Research Database (Denmark)

    Stapper, A.P.; Narasimhan, G.; Oman, D.E.;

    2004-01-01

    Extracellular polymers can facilitate the non-specific attachment of bacteria to surfaces and hold together developing biofilms. This study was undertaken to qualitatively and quantitatively compare the architecture of biofilms produced by Pseudomonas aeruginosa strain PAO1 and its alginate...... biofilm formation using confocal laser scanning microscopy. Biofilm Image Processing (BIP) and Community Statistics (COMSTAT) software programs were used to provide quantitative measurements of the two-dimensional biofilm images. All three strains formed distinguishable biofilm architectures, indicating...... that the production of alginate is not critical for biofilm formation. Observation over a period of 5 days indicated a three-stage development pattern consisting of initiation, establishment and maturation. Furthermore, this study showed that phenotypically distinguishable biofilms can be...

  6. Co(II) removal by magnetic alginate beads containing Cyanex 272.

    Science.gov (United States)

    Ngomsik, Audrey-Flore; Bee, Agnès; Siaugue, Jean-Michel; Talbot, Delphine; Cabuil, Valérie; Cote, Gérard

    2009-07-30

    In this study, a series of batch experiments is conducted to investigate the ability of magnetic alginate beads containing Cyanex 272 to remove Co(II) ions from aqueous solutions. Equilibrium sorption experiments show a Co(II) uptake capacity of 0.4 mmol g(-1). The data are successfully modelled with a Langmuir equation. A series of kinetics experiments is then carried out and a pseudo-second order equation is used to fit the experimental data. The effect of pH on the sorption of Co(II) ions is also investigated. Desorption experiments by elution of the loaded beads with nitric acid at pH 1 show that the magnetic alginate beads could be reused without significant losses of their initial properties even after 3 adsorption-desorption cycles. PMID:19157703

  7. Pulsed-low intensity ultrasound enhances extracellular matrix production by fibroblasts encapsulated in alginate

    Directory of Open Access Journals (Sweden)

    Siti PM Bohari

    2012-07-01

    Full Text Available In this study, the effect of pulsed-low intensity ultrasound on cell proliferation, collagen production and glycosaminoglycan deposition by 3T3 fibroblasts encapsulated in alginate was evaluated. Hoechst 33258 assay for cell number, hydroxyproline assay for collagen content and dimethylamine blue assay for glycosaminoglycan content were performed on samples from cell cultures treated with pulsed-low intensity ultrasound and a control group. Pulsed-low intensity ultrasound shows no effect on cell proliferation, while collagen and glycosaminoglycan contents were consistently higher in the samples treated with pulsed-low intensity ultrasound, showing a statistically significant difference (p < 0.05 on day 10. Alcian blue staining showed that glycosaminoglycans were deposited around the cells in both groups. These results suggest that pulsed-low intensity ultrasound shows no effect on cell proliferation but has potential for inducing collagen and glycosaminoglycan production in cells cultured in alginate gels.

  8. Modifications on the properties of a calcium phosphate cement by additions of sodium alginate

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, W.T.; Fernandes, J.M.; Vieira, R.S.; Thurmer, M.B.; Santos, L.A., E-mail: trajano@ufrgs.br, E-mail: julianafernandes2@yahoo.com.br, E-mail: rsvieira.eng@gmail.com, E-mail: monicathurmer@yahoo.com.br, E-mail: luis.santos@ufrgs.br [Universidade Federal do Rio Grande do Sul (PPG/LABIOMAT/UFRGS), RS (Brazil)

    2012-07-01

    The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified. (author)

  9. Serum Albumin-Alginate Microparticles Prepared by Transacylation: Relationship between Physicochemical, Structural and Functional Properties.

    Science.gov (United States)

    Hadef, Imane; Rogé, Barbara; Edwards-Lévy, Florence

    2015-08-10

    Our laboratory develops a method of microencapsulation using a transacylation reaction in a water-in-oil (W/O) emulsion. The method is based on the creation of amide bonds between free amine functions of a protein (human serum albumin (HSA)) and ester groups of propylene glycol alginate (PGA) in the inner aqueous phase after alkalization. The aim of this work is to study the influence of physicochemical properties of HSA-PGA mixtures on microparticle characteristics. Microparticles were prepared varying the concentrations of PGA and HSA, then characterized (inner structure, size, swelling rate, release kinetics). PGA and each polymer mixture used in the microencapsulation procedure were examined in order to elucidate the mechanism of microstructure formation. It was found that the morphology and functional properties of HSA-alginate microparticles were related to the two polymer concentrations in the aqueous solution. Actually, the polymer concentration variations led to physicochemical changes, which affected the microparticle structure and functional properties. PMID:26121308

  10. Physical evaluation of biodegradable films of calcium alginate plasticized with polyols

    Directory of Open Access Journals (Sweden)

    A. A. Santana

    2013-12-01

    Full Text Available The influence of different polyols as plasticizers of alginate films on their physical attributes like moisture content, soluble mass in water, water uptake, water vapor permeability, opacity and mechanical properties were determined and the results discussed based on scanning electron microscopy observations and glass transition temperature. The alginate films were obtained by casting, using three different gramatures. Calcium crosslinked and non-reticulated films were considered. The films plasticized with glycerol and xylitol were more hygroscopic than the films with mannitol. The lowest water vapor permeability values were found for films plasticized with mannitol, at all studied thicknesses. The films plasticized with glycerol and xylitol showed very similar functional attributes regarding their application as food wrappings. The Ca2+ crosslinked mannitol films showed the highest tensile strength at rupture (>140 MPa.

  11. TEMPO-oxidized nanocellulose participating as crosslinking aid for alginate-based sponges.

    Science.gov (United States)

    Lin, Ning; Bruzzese, Cécile; Dufresne, Alain

    2012-09-26

    Crosslinked polysaccharide sponges have been prepared by freeze-drying of amorphous alginate-oxidized nanocellulose in the presence of a Ca(2+) ionic crosslinking agent. The new carboxyl groups on the surface of nanocellulose induced by the chemical oxidization provided the possibility of participating in the construction of an alginate-based sponge's structure and played a fundamental role in the structural and mechanical stability of ensuing sponges. Furthermore, enhanced mechanical strength induced by oxidized cellulose nanocrystals and the formation of a semi-interpenetrating polymer network from oxidized microfibrillated cellulose were reported. Together with the facile and ionic crosslinking process, the ultrahigh porosity, promising water absorption and retention, as well as the improved compression strength of the crosslinked sponges should significantly extend the use of this soft material in diverse practical applications. PMID:22950801

  12. Glutathione and S-nitrosoglutathione in alginate/chitosan nanoparticles: Cytotoxicity

    Science.gov (United States)

    Marcato, P. D.; Adami, L. F.; Melo, P. S.; de Paula, L. B.; Durán, N.; Seabra, A. B.

    2011-07-01

    Nitric oxide (NO) is involved in several physiological processes, such as the control of vascular tone, the immune response and the wound healing process. Thus, there is a great interest in the development of NO-releasing drugs and in matrices which are able to stabilize and release NO locally in different tissues. Thiols, such as glutathione (GSH), are ready nitrosated to form the NO donors S-nitrosothiols (RSNOs). In this work, GSH, a precursor of the NO donor S-nitrosoglutathione (GSNO), was encapsulated into a mucoadhesive combination of alginate/chitosan nanoparticles. The encapsulated GSH was nitrosated in the alginate/chitosan nanoparticles by adding sodium nitrite, leading to the formation of encapsulated GSNO. The cytotoxicity characterization of the nanoparticles containing either GSH or GSNO showed that these materials were completely non cytotoxic to cellular viability. These results show that this novel nanostructure biomaterial has a great potential to be use in biomedical applications where NO has a therapeutical effect.

  13. Glutathione and S-nitrosoglutathione in alginate/chitosan nanoparticles: Cytotoxicity

    International Nuclear Information System (INIS)

    Nitric oxide (NO) is involved in several physiological processes, such as the control of vascular tone, the immune response and the wound healing process. Thus, there is a great interest in the development of NO-releasing drugs and in matrices which are able to stabilize and release NO locally in different tissues. Thiols, such as glutathione (GSH), are ready nitrosated to form the NO donors S-nitrosothiols (RSNOs). In this work, GSH, a precursor of the NO donor S-nitrosoglutathione (GSNO), was encapsulated into a mucoadhesive combination of alginate/chitosan nanoparticles. The encapsulated GSH was nitrosated in the alginate/chitosan nanoparticles by adding sodium nitrite, leading to the formation of encapsulated GSNO. The cytotoxicity characterization of the nanoparticles containing either GSH or GSNO showed that these materials were completely non cytotoxic to cellular viability. These results show that this novel nanostructure biomaterial has a great potential to be use in biomedical applications where NO has a therapeutical effect.

  14. Modifications on the properties of a calcium phosphate cement by additions of sodium alginate

    International Nuclear Information System (INIS)

    The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified. (author)

  15. Effect of calcium alginate coating on shelf life of frozen lamb muscle

    Directory of Open Access Journals (Sweden)

    Mohammadreza Koushki

    2015-11-01

    Full Text Available Considering the potential benefits of edible coatings and films for storage of food materials, effect of edible calcium alginate film on shelf life of frozen lamb muscles was studied in the present research. Microbial analyses including total microorganisms count and psychrophilic bacteria count and chemical analyses such as total volatile nitrogen (TVN and moisture content determination were performed. Coated and uncoated samples had not statistically significant difference in total microbial count, total volatile nitrogen level and moisture content. However, there was statistically significant difference between the coated and uncoated samples in terms of psychrophilic bacteria count (p<0.05. Considering the role of psychrophilic bacteria in meat spoilage, results of the current research confirmed that calcium alginate films may be to some extent effective in shelf life extension of frozen lamb muscle.

  16. Development of a new antibacterial biomaterial by tetracycline immobilization on calcium-alginate beads.

    Science.gov (United States)

    Ozseker, Emine Erdogan; Akkaya, Alper

    2016-10-20

    In recent years, increasing risk of infection, caused by resistant microorganism to antibiotics, has become the limelight discovery of new and natural antibacterial materials. Heavy metals, such as silver, copper, mercury and titanium, have antibacterial activity. Products, which improved these metals, do not have stable antibacterial property. Therefore, use of these products is restricted. The aim of this study was to immobilize tetracycline to alginate and improve an antibacterial biomaterial. For this purpose, calcium-alginate beads were formed by dropping to calcium-chloride solution and tetracycline was immobilized to beads using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at optimum conditions. After immobilization, actualization of immobilization was investigated by analyzing ATR-FTIR spectrum and SEM images. Also, antibacterial property of obtained product was tested. Improved product demonstrated antibacterial property. It has potential for open wound, surgical drapes, bed and pillow sheath in hospitals and it may also be used for increasing human comfort in daily life. PMID:27474587

  17. Preparation and activity of bubbling-immobilized cellobiase within chitosan-alginate composite.

    Science.gov (United States)

    Wang, Fang; Su, Rong-Xin; Qi, Wei; Zhang, Ming-Jia; He, Zhi-Min

    2010-01-01

    Cellobiase can hydrolyze cellobiose into glucose; it plays a key role in the process of cellulose hydrolysis by reducing the product inhibition. To reuse the enzyme and improve the economic value of cellulosic ethanol, cellobiase was immobilized using sodium alginate and chitosan as carriers by the bubbling method. The immobilization conditions were optimized as follows: enzyme loading of 100 U cellobiase/g carrier, 30 min immobilization, 3.5 wt% sodium alginate, 0.25 wt% chitosan, and 2 wt% calcium chloride. Compared to free enzyme, the immobilized cellobiase had a decreased apparent K(m) and the maximum activity at a lower pH, indicating its higher acidic and thermal stability. The immobilized cellobiase was further tested in the hydrolysis of cellobiose and various cellulosic substrates (microcrystalline cellulose, filter paper, and ammonia-pretreated corn cobs). Together with cellulases, the immobilized cellobiase converted the cellulosic substrates into glucose with the rate and extent similar to the free enzyme. PMID:20024795

  18. Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

    Science.gov (United States)

    Lin, Shen-Fu; Chen, Ying-Chen; Chen, Ray-Neng; Chen, Ling-Chun; Ho, Hsiu-O; Tsung, Yu-Han; Sheu, Ming-Thau; Liu, Der-Zen

    2016-01-01

    There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds. PMID:27093175

  19. Extraction of alginate biopolymer present in marine alga sargassum filipendula and bioadsorption of metallic ions

    Directory of Open Access Journals (Sweden)

    Sirlei Jaiana Kleinübing

    2013-04-01

    Full Text Available This paper studies the bioadsorption of Pb2+, Cu2+, Cd2+ and Zn2+ ions by marine alga Sargassum filipendula and by the alginate biopolymer extracted from this alga. The objective is to evaluate the importance of this biopolymer in removing different metallic ions by the marine alga S. filipendula. In the equilibrium study, the same affinity order was observed for both bioadsorbents: Pb2+ > Cu2+ > Zn2+ > Cd2+. For Pb2+ and Cu2+ ions when the alginate is isolated and acting as bioadsorbents, adsorption capacities greater than those found for the alga were observed, indicating that it is the main component responsible for the removal of metallic ions. For Zn2+ and Cd2+ ions, greater bioadsorption capacities were observed for the alga, indicating that other functional groups of the alga, such as sulfates and amino, are also important in the bioadsorption of these ions.

  20. Recovery of zinc, cadmium, and lanthanum by biopolymer gel particles of alginic acid

    International Nuclear Information System (INIS)

    Biopolymer gel particles of alginic acid were found to be a useful material for recovering zinc, cadmium, and lanthanum from aqueous solutions. The metals sorbed by the gel particles could be completely eluted by using dilute HCl solution of 0.1 kmol/m3. The distribution ratios of the individual metals between the gel and liquid phases were measured by using a batch method. The equilibrium data were consistent with predictions made assuming that sorption takes place with the ion-exchange reaction between metal ions and alginic acid. The maximum sorption capacity of the gel particles and the distribution equilibrium constants for the metals were determined by comparing the experimental data with the theoretical predictions. The observed effect of temperature on the distribution equilibrium was insignificant in the range from 15 to 35 degrees C. 17 refs., 6 figs., 1 tab

  1. Immobilization of Laccase in Alginate-Gelatin Mixed Gel and Decolorization of Synthetic Dyes

    Science.gov (United States)

    Mogharabi, Mehdi; Nassiri-Koopaei, Nasser; Bozorgi-Koushalshahi, Maryam; Nafissi-Varcheh, Nastaran; Bagherzadeh, Ghodsieh; Faramarzi, Mohammad Ali

    2012-01-01

    Alginate-gelatin mixed gel was applied to immobilized laccase for decolorization of some synthetic dyes including crystal violet. The immobilization procedure was accomplished by adding alginate to a gelatin solution containing the enzyme and the subsequent dropwise addition of the mixture into a stirred CaCl2 solution. The obtained data showed that both immobilized and free enzymes acted optimally at 50°C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme. The immobilized enzyme represented optimum decolorization at pH 8. Reusability of the entrapped laccase was also studied and the results showed that ca. 85% activity was retained after five successive cycles. The best removal condition was applied for decolorization of seven other synthetic dyes. Results showed that the maximum and minimum dye removal was related to amido black 10B and eosin, respectively. PMID:22899898

  2. Immobilization of Laccase in Alginate-Gelatin Mixed Gel and Decolorization of Synthetic Dyes

    Directory of Open Access Journals (Sweden)

    Mehdi Mogharabi

    2012-01-01

    Full Text Available Alginate-gelatin mixed gel was applied to immobilized laccase for decolorization of some synthetic dyes including crystal violet. The immobilization procedure was accomplished by adding alginate to a gelatin solution containing the enzyme and the subsequent dropwise addition of the mixture into a stirred CaCl2 solution. The obtained data showed that both immobilized and free enzymes acted optimally at 50°C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme. The immobilized enzyme represented optimum decolorization at pH 8. Reusability of the entrapped laccase was also studied and the results showed that ca. 85% activity was retained after five successive cycles. The best removal condition was applied for decolorization of seven other synthetic dyes. Results showed that the maximum and minimum dye removal was related to amido black 10B and eosin, respectively.

  3. Modelling rheology of isothermal flow of carboxymethyl cellulose-alginate suspension in a horizontal conduit

    International Nuclear Information System (INIS)

    The rheology of isothermal flow of Carboxymethylcellulose (CMC) solution at 0.5 % mass concentration and, loaded with spherical alginate particles was modeled and analysed. A carrier fluid flow model of solid-liquid pseudoplastic Non-Newtonian suspension in a horizontal pipe governed by constitutive power law of Ostwald Wan der Waal was found not applicable to the range of experimental shearing rates of the flow regime of CMC alginate suspension. Therefore, a new model based on the effect of dynamic viscosity on concentration of the spherical particles in Newtonian flow regimes in relation to Brownian activated motion and hydrodynamics was developed to account for zero shear viscosity and resolve other physical limitations. Upon validation, the dynamic viscosity model fitted the experimental data of the shearing rates. (au)

  4. Design and characterization of self-assembled fish sarcoplasmic protein-alginate nanocomplexes

    DEFF Research Database (Denmark)

    Boutrup Stephansen, Karen; Mattebjerg, Maria Ahlm; Wattjes, Jasper;

    2015-01-01

    Macrostructures based on natural polymers are subject to large attention, as the application range is wide within the food and pharmaceutical industries. In this study we present nanocomplexes (NCXs) made from electrostatic self-assembly between negatively charged alginate and positively charged...... caused a decreased viability in HeLa and U2OS cell lines. The simple processing procedure and the high stability of the NCXs, makes them excellent candidates for use in the food and pharmaceutical industry. (C) 2015 Elsevier B.V. All rights reserved....... fish sarcoplasmic proteins (FSP), prepared by bulk mixing. A concentration screening revealed that there was a range of alginate and FSP concentrations where stable NCXs with similar properties were formed, rather than two exact concentrations. The size of the NCXs was 293 +/- 3 nm, and the zeta...

  5. A comparative study on liquid core formulation on the diameter on the alginate capsules

    Science.gov (United States)

    Ong, Hui-Yen; Lee, Boon-Beng; Radzi, AkmalHadi Ma'; Zakaria, Zarina; Chan, Eng-Seng

    2015-08-01

    Liquid core capsule has vast application in biotechnology related industries such as pharmaceutical, medical, agriculture and food. Formulation of different types of capsule was important to determine the performance of the capsule. Generally, the liquid core capsule with different formulations generated different size of capsule.Therefore, the aim of this project is to investigate the effect of different liquid core solution formulations on the diameter of capsule. The capsule produced by extruding liquid core solutions into sodium alginate solution. Three types of liquid core solutions (chitosan, xanthan gum, polyethylene glycol (PEG)) were investigated. The results showed that there is significant change in capsule diameter despite in different types of liquid core solution were used and a series of capsule range in diameter of 3.1 mm to 4.5 mm were produced. Alginate capsule with chitosan formulation appeared to be the largest capsule among all.

  6. Effect of Diffusion on Discoloration of Congo Red by Alginate Entrapped Turnip (Brassica rapa) Peroxidase

    OpenAIRE

    Afaf Ahmedi; Mahmoud Abouseoud; Amrane Abdeltif; Couvert Annabelle

    2015-01-01

    Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip “Brassica rapa” is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, cons...

  7. A Simple, Quantitative Method Using Alginate Gel to Determine Rat Colonic Tumor Volume In Vivo

    OpenAIRE

    Amy A. Irving; Young, Lindsay B; Pleiman, Jennifer K; Konrath, Michael J; Marzella, Blake; Nonte, Michael; Cacciatore, Justin; Ford, Madeline R; Clipson, Linda; Amos-Landgraf, James M.; Dove, William F.

    2014-01-01

    Many studies of the response of colonic tumors to therapeutics use tumor multiplicity as the endpoint to determine the effectiveness of the agent. These studies can be greatly enhanced by accurate measurements of tumor volume. Here we present a quantitative method to easily and accurately determine colonic tumor volume. This approach uses a biocompatible alginate to create a negative mold of a tumor-bearing colon; this mold is then used to make positive casts of dental stone that replicate th...

  8. Microfluidic Directed Synthesis of Alginate Nanogels with Tunable Pore Size for Efficient Protein Delivery.

    Science.gov (United States)

    Bazban-Shotorbani, Salime; Dashtimoghadam, Erfan; Karkhaneh, Akbar; Hasani-Sadrabadi, Mohammad Mahdi; Jacob, Karl I

    2016-05-17

    Alginate is a biopolymer with favorable pH-sensitive properties for oral delivery of peptides and proteins. However, conventional alginate nanogels have limitations such as low encapsulation efficiency because of drug leaching during bead preparation and burst release in high pH values. These shortcomings originate from large pore size of the nanogels. In this work, we proposed an on-chip hydrodynamic flow focusing approach for synthesis of alginate nanogels with adjustable pore size to achieve fine-tunable release profile of the encapsulated bioactive agents. It is demonstrated that the microstructure of nanogels can be controlled through adjusting flow ratio and mixing time directed on microfluidic platforms consisting of cross-junction microchannels. In this study, the average pore size of alginate nanogels (i.e., average molecular weight between cross-links, Mc) was related to synthesis parameters. Mc was calculated from equations based on equilibrium swelling theory and proposed methods to modify the theory for pH-sensitive nanogels. In the equations we derived, size and compactness of nanogels are key factors, which can be adjusted by controlling the flow ratio. It was found that increase in flow ratio increases the size of nanogels and decreases their compactness. The size of on-chip generated nanogels for flow ratio of 0.02-0.2 was measured to be in the range of 68-138 nm. Moreover, a method based on the Mie theory was implemented to estimate the aggregation number (Nagg) of polymer chains inside the nanogels as an indicator of compactness. According to the size and compactness results along with equations of modified swelling theory, Mc obtained to be in the range of 0.5-0.8 kDa. The proposed method could be considered as a promising approach for efficient polypeptides encapsulation and their sustained release. PMID:26938744

  9. Alginate and DNA gels are suitable delivery systems for diabetic wound healing

    OpenAIRE

    Tellechea, A; Silva, EA; Min, J.; Leal, EC; Auster, ME; Pradhan-Nabzdyk, L; Shih, W; Mooney, DJ; Veves, A

    2015-01-01

    © The Author(s) 2014. Diabetic foot ulcers (DFU) represent a severe health problem and an unmet clinical challenge. In this study, we tested the efficacy of novel biomaterials in improving wound healing in mouse models of diabetes mellitus (DM). The biomaterials are composed of alginate- and deoxyribonucleic acid (DNA)-based gels that allow incorporation of effector cells, such as outgrowth endothelial cells (OEC), and provide sustained release of bioactive factors, such as neuropeptides and ...

  10. CHO immobilization in alginate/poly-l-lysine microcapsules: an understanding of potential and limitations

    Science.gov (United States)

    Breguet, Véronique; Gugerli, Raphaël; von Stockar, Urs

    2007-01-01

    Microencapsulation offers a unique potential for high cell density, high productivity mammalian cell cultures. However, for successful exploitation there is the need for microcapsules of defined size, properties and mechanical stability. Four types of alginate/poly-l-Lysine microcapsules, containing recombinant CHO cells, have been investigated: (a) 800 μm liquid core microcapsules, (b) 500 μm liquid core microcapsules, (c) 880 μm liquid core microcapsules with a double PLL membrane and (d) 740 μm semi-liquid core microcapsules. With encapsulated cells a reduced growth rate was observed, however this was accompanied by a 2–3 fold higher specific production rate of the recombinant protein. Interestingly, the maximal intracapsular cell concentration was only 8.7 × 107 cell mL-1, corresponding to a colonization of 20% of the microcapsule volume. The low level of colonization is unlikely to be due to diffusional limitations since reduction of microcapsule size had no effect. Measurement of cell leaching and mechanical properties showed that liquid core microcapsules are not suitable for continuous long-term cultures (>1 month). By contrast semi-liquid core microcapsules were stable over long periods with a constant level of cell colonization (ϕ = 3%). This indicates that the alginate in the core plays a predominant role in determining the level of microcapsule colonization. This was confirmed by experiments showing reduced growth rates of batch suspension cultures of CHO cells in medium containing dissolved alginate. Removal of this alginate would therefore be expected to increase microcapsule colonization. PMID:19003193

  11. CHO immobilization in alginate/poly-l-lysine microcapsules: an understanding of potential and limitations

    OpenAIRE

    Breguet, Véronique; Gugerli, Raphaël; von Stockar, Urs; Marison, Ian William

    2007-01-01

    Microencapsulation offers a unique potential for high cell density, high productivity mammalian cell cultures. However, for successful exploitation there is the need for microcapsules of defined size, properties and mechanical stability. Four types of alginate/poly-l-Lysine microcapsules, containing recombinant CHO cells, have been investigated: (a) 800 μm liquid core microcapsules, (b) 500 μm liquid core microcapsules, (c) 880 μm liquid core microcapsules with a double PLL membrane and (d) 7...

  12. In-vivo evaluation of clindamycin release from glyceryl monooleate-alginate microspheres by NIR spectroscopy.

    Science.gov (United States)

    Mohamed, Amir Ibrahim; Ahmed, Osama A A; Amin, Suzan; Elkadi, Omar Anwar; Kassem, Mohamed A

    2015-10-15

    The purpose of this study was to use near-infrared (NIR) transmission spectroscopic technique to determine clindamycin plasma concentration after oral administration of clindamycin loaded GMO-alginate microspheres using rabbits as animal models. Lyophilized clindamycin-plasma standard samples at a concentration range of 0.001-10 μg/ml were prepared and analyzed by NIR and HPLC as a reference method. NIR calibration model was developed with partial least square (PLS) regression analysis. Then, a single dose in-vivo evaluation was carried out and clindamycin-plasma concentration was estimated by NIR. Over 24 h time period, the pharmacokinetic parameters of clindamycin were calculated for the clindamycin loaded GMO-alginate microspheres (F3) and alginate microspheres (F2), and compared with the plain drug (F1). PLS calibration model with 7-principal components (PC), and 8000-9200 cm(-1) spectral range shows a good correlation between HPLC and NIR values with root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP), and calibration coefficient (R(2)) values of 0.245, 1.164, and 0.9753, respectively, which suggests that NIR transmission technique can be used for drug-plasma analysis without any extraction procedure. F3 microspheres exhibited controlled and prolonged absorption Tmax of 4.0 vs. 1.0 and 0.5 h; Cmax of 2.37±0.3 vs. 3.81±0.8 and 5.43±0.7 μg/ml for F2 and F1, respectively. These results suggest that the combination of GMO and alginate (1:4 w/w) could be successfully employed for once daily clindamycin microspheres formulation which confirmed by low Cmax and high Tmax values. PMID:26276253

  13. The reinforcement and healing of asphalt mastic mixtures by rejuvenator encapsulation in alginate compartmented fibres

    Science.gov (United States)

    Tabaković, A.; Post, W.; Cantero, D.; Copuroglu, O.; Garcia, S. J.; Schlangen, E.

    2016-08-01

    This paper explores the potential use of compartmented alginate fibres as a new method of incorporating rejuvenators into asphalt pavement mixtures. The compartmented fibres are employed to locally distribute the rejuvenator and to overcome the problems associated with spherical capsules and hollow fibres. The work presents proof of concept of the encapsulation process which involved embedding the fibres into the asphalt mastic mixture and the survival rate of fibres in the asphalt mixture. To prove the effectiveness of the alginate as a rejuvenator encapsulating material and to demonstrate its ability survive asphalt production process, the fibres containing the rejuvenator were prepared and subjected to thermogravimetric analysis and uniaxial tensile test. The test results demonstrated that fibres have suitable thermal and mechanical strength to survive the asphalt mixing and compaction process. The CT scan of an asphalt mortar mix containing fibres demonstrated that fibres are present in the mix in their full length, undamaged, providing confirmation that the fibres survived the asphalt production process. In order to investigate the fibres physiological properties and ability to release the rejuvenator into cracks in the asphalt mastic, the environmental scanning electron microscope and optical microscope analysis were employed. To prove its success as an asphalt healing system, compartmented alginate fibres containing rejuvenator were embedded in asphalt mastic mix. The three point bend tests were performed on the asphalt mastic test samples and the degree to which the samples began to self-heal in response was measured and quantified. The research findings indicate that alginate fibres present a promising new approach for the development of self-healing asphalt pavement systems.

  14. Quantifying Pb and Cd complexation by alginates and the role of metal binding on macromolecular aggregation

    OpenAIRE

    Lamelas, Cristina; Avaltroni, F; Benedetti, Marc,; Wilkinson, Kevin J; Slaveykova, Vera

    2005-01-01

    The Pb and Cd binding capacity of alginates were quantified by the determination of their complex stability constants and the concentration of complexing sites using H+, Pb2+, or Cd2+ selective electrodes in both static and dynamic titrations. Centrifugation filter devices (30 kDa filter cutoff), followed by inductively coupled plasma mass spectrometry (ICP-MS) measurements of lead or cadmium in the filtrates, were used to validate the results. The influence of ionic strength, pH, and the met...

  15. Development of Alginate Microspheres Containing Chuanxiong for Oral Administration to Adult Zebrafish

    OpenAIRE

    Li-Jen Lin; Chung-Jen Chiang; Yun-Peng Chao; Shulhn-Der Wang; Yu-Ting Chiou; Han-Yu Wang; Shung-Te Kao

    2016-01-01

    Oral administration of Traditional Chinese Medicine (TCM) by patients is the common way to treat health problems. Zebrafish emerges as an excellent animal model for the pharmacology investigation. However, the oral delivery system of TCM in zebrafish has not been established so far. This issue was addressed by development of alginate microparticles for oral delivery of chuanxiong, a TCM that displays antifibrotic and antiproliferative effects on hepatocytes. The delivery microparticles were p...

  16. Sodium Alginate Microneedle Arrays Mediate the Transdermal Delivery of Bovine Serum Albumin

    OpenAIRE

    Yusuf K Demir; Zafer Akan; Oya Kerimoglu

    2013-01-01

    BACKGROUND: The "poke and release" strategy for the delivery of macromolecules using polymeric microneedle (MN) is of great importance because it eliminates microneedle reuse, the risks of biohazardous sharps and cross contamination, and it requires no special disposal mechanism. The main objective of this study was the determination of the stability and delivery of bovine serum albumin (BSA) that was transported across human skin via sodium alginate (SA) microneedle arrays (MNs) and SA needl...

  17. Microencapsulation of natural antioxidants from Pterospartum tridentatum in different alginate and inulin systems

    OpenAIRE

    Isailović, B.; Kalušević, A.; Žuržul, N; Coelho, M.T.; Đorđević, V.; Alves, V; Sousa, I; M. M. MARTINS; Bugarski, B.; Nedović, V.

    2012-01-01

    The bioactivity of natural antioxidants from plant extracts is well known. Still, the effectiveness of these natural antioxidants, namely polyphenols, depends on preserving their stability, which can be increased by microencapsulation. The aim of this study was to protect natural antioxidants from the aqueous extract of Portuguese wild herb Pterospartum tridentatum by encapsulation in alginate hydrogel microbeads. Microbeads were prepared by electrostatic extrusion technique: p...

  18. Sodium Alginate Based Mucoadhesive System for Gatifloxacin and Its In Vitro Antibacterial Activity

    OpenAIRE

    Kesavan, Karthikeyan; Nath, Gopal; Pandit, Jayanta K.

    2010-01-01

    The objective of this study was to formulate sodium alginate based ophthalmic mucoadhesive system of gatifloxacin and its in vitro antibacterial potential on pathogenic microorganisms, Staphylococcus aureus and Escherichia coli. Sodium carboxymethylcellulose (NaCMC) was added to the formulations to enhance the gel bioadhesion properties. The prepared formulations were evaluated for their in vitro drug release, gelation behaviour, rheological behavior, and mucoadhesion force. All formulations ...

  19. Composite alginate hydrogel microparticulate delivery system of zidovudine hydrochloride based on counter ion induced aggregation

    OpenAIRE

    Roy, Harekrishna; Rao, P. Venkateswar; Panda, Sanjay Kumar; Biswal, Asim Kumar; Parida, Kirti Ranjan; Dash, Jharana

    2014-01-01

    Aim: The present study deals with preparation of zidovudine loaded microparticle by counter ion induced aggregation method. During this study effect of polyacrylates and hypromellose polymers on release study were investigated. Materials and Methods: The ion induced aggregated alginate based microparticles were characterized for surface morphology, particle size analysis, drug entrapment study, in-vitro study, Fourier-transform infrared (FTIR) spectroscopy, and differential scanning calorimet...

  20. Study of Impingement Types and Printing Quality during Laser Printing of Viscoelastic Alginate Solutions.

    Science.gov (United States)

    Zhang, Zhengyi; Xiong, Ruitong; Corr, David T; Huang, Yong

    2016-03-29

    Laser-induced forward transfer-based laser printing has been being implemented as a promising orifice-free direct-write strategy for different printing applications. The printing quality during laser printing is largely affected by the jet and droplet formation process and subsequential impingement. The objective of this study is to investigate the impingement-based printing type and resulting printing quality during the laser printing of viscoelastic alginate solutions, which are representative inks for soft structure printing such as bioprinting. Three printing types are identified: droplet-impingement printing, jet-impingement printing with multiple breakups, and jet-impingement printing with a single breakup. Printing quality, in terms of printed droplet morphology and size, has been investigated as a function of alginate concentration, laser fluence, and direct-writing height based on a time-resolved imaging approach and microarrays of printed droplets. Of these, the best printing quality is achieved with single-breakup jet-impingement printing, followed by multiple-breakup jet-impingement printing, with droplet-impingement printing producing the lowest quality printing. The printing quality can be improved by using high-concentration alginate solutions. The increase of laser fluence may lead to a well-defined primary droplet for low-concentration alginate solutions; however, this can cause the droplet diameter to increase, which may not be desirable. The direct-writing height (i.e., ribbon coating-receiving substrate distance) also influences the print quality. For example, an increase in direct-writing height can cause the printing type to change from the ideal jet-impingement with a single breakup, to the jet-impingement with multiple breakups, and even the least desired droplet-impingement printing, with only slight variations in droplet diameter. PMID:26934283

  1. The bactericidal effect of dendritic copper microparticles, contained in an alginate matrix, on Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Simon F Thomas

    Full Text Available Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 10(6 cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 10(8 cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate.

  2. Production of ethanol from cellobiose using immobilized beta-glucosidase coentrapped with yeast in alginate gels

    Energy Technology Data Exchange (ETDEWEB)

    Kierstan, M.; McHale, A.; Coughlan, M.P.

    1982-06-01

    Enzymatic hydrolysis of cellulose by Talaromyces emersonii is slowed markedly by the accumulation of considerable quantities of cellobiose. This article outlines a novel method for overcoming this problem whereby a culture filtrate containing a complete cellulase system be used in combination with calcium alginate gels containing both yeast and immobilized beta-glucosidase. As a preliminary to a full study, the experimental results of cellobiose conversion to ethanol are reported. (Refs. 13).

  3. Effect of calcium alginate coating on shelf life of frozen lamb muscle

    OpenAIRE

    Mohammadreza Koushki; Mohammad Hossein Azizi; Paliz Koohy-Kamaly; Zohreh Amiri; Mohammad Azizkhani

    2015-01-01

    Considering the potential benefits of edible coatings and films for storage of food materials, effect of edible calcium alginate film on shelf life of frozen lamb muscles was studied in the present research. Microbial analyses including total microorganisms count and psychrophilic bacteria count and chemical analyses such as total volatile nitrogen (TVN) and moisture content determination were performed. Coated and uncoated samples had not statistically significant difference in total microbi...

  4. Production and Characterization of Alginate Microcapsules Produced by a Vibrational Encapsulation Device

    OpenAIRE

    Mazzitelli, S.; A. Tosi; BALESTRA, C; Nastruzzi, C.; De Luca, G.; Mancuso, F; Calafiore, R.; M Calvitti

    2008-01-01

    Abstract The optimization, through a Design of Experiments (DoE) approach, of a microencapsulation procedure for isolated neonatal porcine islets (NPI) is described. The applied method is based on the generation of monodisperse droplets by a vibrational nozzle. An alginate/polyornithine encapsulation procedure, developed and validated in our laboratory for almost a decade, was used to embody pancreatic islets. We analyzed different experimental parameters including frequency of vib...

  5. in Situ Formation of a Biocatalytic Alginate Membrane by Enhanced Concentration Polarization

    DEFF Research Database (Denmark)

    Marpani, Fauziah; Luo, Jianquan; Mateiu, Ramona Valentina; Meyer, Anne S.; Pinelo, Manuel

    2015-01-01

    A thin alginate layer induced on the surface of a commercial polysulfone membrane was used as a matrix for noncovalent immobilization of enzymes. Despite the expected decrease of flux across the membrane resulting from the coating, the initial hypothesis was that such a system should allow high i...... consequence on the type of immobilization promoted in each phase. The results suggested that the strategy proposed could be efficiently used to enhance the enzyme loading on polymer membranes....

  6. Radiolytically degraded sodium alginate enhances plant growth, physiological activities and alkaloids production in Catharanthus roseus L.

    OpenAIRE

    Naeem, M.; Tariq Aftab; Abid A. Ansari; Mohd Idrees; Akbar Ali; Khan, M. Masroor A.; Moin Uddin; Lalit Varshney

    2015-01-01

    Catharanthus roseus (L.) G. Don (Family Apocynaceae) is a medicinal plant that produces indole alkaloids used in cancer chemotherapy. The anticancerous alkaloids, viz. vinblastine and vincristine, are mainly present in the leaves of C. roseus. High demand and low yield of these alkaloids in the plant has led to explore the alternative means for their production. Gamma irradiated sodium alginate (ISA) has proved as a plant growth promoting substance for various medicinal and agricultural crops...

  7. Alginate polylysine microcapsules as immune barrier: permeability of cytokines and immunoglobulins over the capsule membrane.

    Science.gov (United States)

    Kulseng, B; Thu, B; Espevik, T; Skjåk-Braek, G

    1997-01-01

    Transplantation of pancreatic islets in alginate polylysine microcapsules is a potential useful method for treating type I diabetes. In this study, the permeability for alginate-polylysine microcapsules to cytokines an immunoglobulines has been investigated by a newly developed method. Magnetic monodisperse polymer particles (Dynabeads) coated with antibodies against selected proteins were encapsulated in 0.7 mm alginate polylysine microcapsules. The capsule membrane permeability to IgG (150 kDa), Transferrin (81 kDa), Tumor necrosis factor (TNF, 51 kDa), Interleukin-1 beta (IL-1 beta, 17.5 kDa), and insulin (5.8 kDa) was estimated by measuring the binding of 125I-labeled proteins to the encapsulated antibody coated Dynabeads. Capsules with an inhomogeneous solid gel core were made of alginates with high guluronic or high mannuronic acid content and poly-L (PLL)- or poly-D-lysine (PDL) of concentrations varied from 0.05-0.2%. The various capsules examined were all impermeable to IgG. The capsules made with a PLL-, but not PDL-membranes were permeable for transferrin. IL-1 beta was found to penetrate all of the different capsule types. The high-G capsules, however, could be made impermeable to TNF and still allowed transferrin to pass. The permeability of these capsules to IL-1 beta, but not to TNF was confirmed in an assay where mouse islets of Langerhans were incubated with TNF and IL-1 beta, and comparing the IL-6 for encapsulated and non-encapsulated islets. PMID:9258512

  8. Modification of pH Conferring Virucidal Activity on Dental Alginates

    Directory of Open Access Journals (Sweden)

    Navina Nallamuthu

    2015-04-01

    Full Text Available To formulate an alginate dental impression material with virucidal properties, experimental alginate dental impression materials were developed and the formulations adjusted in order to study the effect on pH profiles during setting. Commercially available materials served as a comparison. Eight experimental materials were tested for antiviral activity against Herpes Simplex Virus type 1 (HSV-1. Changing the amount of magnesium oxide (MgO used in the experimental formulations had a marked effect on pH. Increasing MgO concentration corresponded with increased pH values. All experimental materials brought about viral log reductions ranging between 0.5 and 4.0 over a period of 4 h. The material with the lowest pH was the most effective. The current work highlights the very important role of MgO in controlling pH profiles. This knowledge has been applied to the formulation of experimental alginates; where materials with pH values of approximately 4.2–4.4 are able to achieve a significant log reduction when assayed against HSV-1.

  9. Research on the Construction of Tissue Engineering Scaffolds by Alginate-hyaluronic Acid with Different Characteristics

    Institute of Scientific and Technical Information of China (English)

    LI Qin-hua; LIU Li; LIN Dong-qing

    2014-01-01

    This research uses alginate and hyaluronic acid as the main component to prepare support, then explores the possibilities as a tissue engineering scaffold. Firstly, prepare HA with various average molecular weight and alginate with different viscosity, mix them up at a certain proportion and make it into a AlgCa 2+-HA composite scaffold with a film-forming method. This article discusses the feasibility of this scaffold used in tissue engineering field according to the consequence of moisture content testing, mechanical analysis, and scanning electron microscopy analysis. The structure and properties of AlgCa2+-HA composite scaffold are closely related to some factors such as average molecular weight of hyaluronic acid, hyaluronic acid concentration, alginate viscosity, cross-linking agents and processing technology. The AlgCa 2+-HA composite material, which is at different proportions and adding different cross-linking agent,has some certain characteristics:moisture content ranging from 50%to 95%, tensile strength between 2.69 N/mm2 and 4.299 N/mm2, and elongation at break is about 58%to 160%. The prepared AlgCa2+-HA composite scaffolds can be used as tissue engineering scaffolds resulting from its high moisture content, good mechanical properties and ideal pore structure.

  10. Sodium alginate sponges with or without sodium hyaluronate: in vitro engineering of cartilage.

    Science.gov (United States)

    Miralles, G; Baudoin, R; Dumas, D; Baptiste, D; Hubert, P; Stoltz, J F; Dellacherie, E; Mainard, D; Netter, P; Payan, E

    2001-11-01

    Studies are underway to design biosystems containing embedded chondrocytes to fill osteochondral defects and to produce a tissue close to native cartilage. In the present report, a new alginate three-dimensional support for chondrocyte culture is described. A sodium alginate solution, with or without hyaluronic acid (HA), was freeze-dried to obtain large-porosity sponges. This formulation was compared with a hydrogel of the same composition. In the sponge formulation, macroscopic and microscopic studies demonstrated the formation of a macroporous network (average pore size, 174 microm) associated with a microporous one (average pore size, 250 nm). Histological and biochemical studies showed that, when loaded with HA, the sponge provides an adapted environment for proteoglycan and collagen synthesis by chondrocytes. Cytoskeleton organization was studied by three-dimensional fluorescence microscopy (CellScan EPR). Chondrocytes exhibit a marked spherical shape with a nonoriented and sparse actin microfilament network. Type II collagen was detected in both types of sponges (with or without HA) using immunohistochemistry. In conclusion, the sponge formulation affords new perspectives with respect to the in vitro production of "artificial" cartilage. Furthermore, the presence of hyaluronate within the alginate sponge mimics a functional environment, suitable for the production by embedded chondrocytes of an extracellular matrix. PMID:11484190

  11. Studies of magnetic alginate-based electrospun matrices crosslinked with different methods for potential hyperthermia treatment.

    Science.gov (United States)

    Chen, Yen-Hsuan; Cheng, Chi-Hui; Chang, Wan-Ju; Lin, Yi-Ching; Lin, Feng-Huei; Lin, Jui-Che

    2016-05-01

    The magnetic electrospun mats were lately established as an innovative biomaterial for hyperthermic cancer treatment. Unlike those surface-modified magnetic nanoparticles that may not firmly adhere onto the tumor for long-term duration, the magnetic mats with nanofibrous structure can promote cell adhesion and kill the tumor directly within an alternating magnetic field. However, most magnetic electrospun mats were fabricated using non-biodegradable polymers and organic solvents, causing the problems of removal after therapy and the suspected biotoxicity associated with residual solvent. Alginate (SA) was utilized in this investigation as the main material for electrospinning because of being biodegradable and water-soluble. The alginate-based electrospun mats were then treated by an ionic or a covalent crosslinking method, and then followed by chelation with Fe(2+)/Fe(3+) for chemical coprecipitation of Fe3O4 magnetic nanoparticles. Significant less cytotoxicity was noted on both liquid extracts from the ionic-crosslinked (Fe3O4-SA/PEO) and covalent-crosslinked (Fe3O4-SA/PVA) magnetic electrospun mats as well as the surface of Fe3O4-SA/PVA. In vitro hyperthermia assay indicated that the covalent-crosslinked magnetic alginate-based mats reduced tumor cell viability greater than Fe3O4 nanoparticles. Such magnetic electrospun mats are of potential for hyperthermia treatment by endoscopic/surgical delivery as well as serving as a supplementary debridement treatment after surgical tumor removal. PMID:26952432

  12. Potential of Alginate Encapsulated Ferric Saccharate Microemulsions to Ameliorate Iron Deficiency in Mice.

    Science.gov (United States)

    Mukhija, Kimmi; Singhal, Kirti; Angmo, Stanzin; Yadav, Kamalendra; Yadav, Hariom; Sandhir, Rajat; Singhal, Nitin Kumar

    2016-07-01

    Iron deficiency is one of the most prominent mineral deficiencies around the world, which especially affects large population of women and children. Development of new technologies to combat iron deficiency is on high demand. Therefore, we developed alginate microcapsule with encapsulated iron that had better oral iron bioavailability. Microcapsules containing iron with varying ratios of sodium alginate ferric(III)-saccharide were prepared using emulsification method. In vitro studies with Caco-2 cells suggested that newly synthesized microemulsions had better iron bioavailability as compared to commercially available iron dextran formulations. Ferrozine in vitro assay showed that alginate-encapsulated ferric galactose microemulsion (AFGM) had highest iron bioavailability in comparison to other four ferric saccharate microemulsions, namely AFGlM, AFMM, AFSM, and AFFM synthesized in our laboratory. Mice studies also suggested that AFGM showed higher iron absorption as indicated by increased serum iron, hemoglobin, and other hematopoietic measures with almost no toxicity at tested doses. Development of iron-loaded microemulsions leads to higher bioavailability of iron and can provide alternative strategies to treat iron deficiency. PMID:26637994

  13. Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model

    Science.gov (United States)

    Cao, Bao; Christophersen, Lars; Jensen, Peter Østrup; Sneppen, Kim; Høiby, Niels; Moser, Claus

    2016-01-01

    Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100–1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm. PMID:27100887

  14. Alginate enhances excretion and reduces absorption of strontium and cesium in rats

    International Nuclear Information System (INIS)

    Alginate (ALA), which is an intercellular polysaccharide associated with brown algae, is used as a food additive, a health food and a medicine. Here, we first examined the adsorption of strontium (Sr) and cesium (Cs) by ALA in vitro, and then evaluated the effects of ALA on absorption and excretion of Sr and Cs in rats, in order to evaluate its potential usefulness for minimizing radiation damage from materials released after a nuclear accident. Both Sr and Cs were concentration-dependently adsorbed by sodium alginate (ALA-Na) in vitro. In rats given diet containing either ALA-Na or calcium alginate (ALA-Ca) for two weeks, the plasma concentration of Sr gradually decreased compared with the controls (normal diet); however, in the case of Cs, the plasma concentration was decreased only in the ALA-Ca group, but not the ALA-Na group. Moreover, we examined the effect of preadministration of diet containing either ALA-Na or ALA-Ca on absorption of Sr and Cs administered orally as the chloride salts to rats. Absorption of both Sr and Cs was reduced in the ALA-Ca group, while absorption of only Sr was reduced in the ALA-Na group. Safety assessments indicated that ALA-Ca is safer than ALA-Na. These results indicate that ALA-Ca reduces absorption and promotes excretion of both Sr and Cs, while ALA-Na does so only for Sr. (author)

  15. Fabrication and optimization of alginate hydrogel constructs for use in 3D neural cell culture

    International Nuclear Information System (INIS)

    Two-dimensional (2D) culture systems provide useful information about many biological processes. However, some applications including tissue engineering, drug transport studies, and analysis of cell growth and dynamics are better studied using three-dimensional (3D) culture systems. 3D culture systems can potentially offer higher degrees of organization and control of cell growth environments, more physiologically relevant diffusion characteristics, and permit the formation of more extensive 3D networks of cell-cell interactions. A 3D culture system has been developed using alginate as a cell scaffold, capable of maintaining the viability and function of a variety of neural cell types. Alginate was functionalized by the covalent attachment of a variety of whole proteins and peptide epitopes selected to provide sites for cell attachment. Alginate constructs were used to entrap a variety of neural cell types including astroglioma cells, astrocytes, microglia and neurons. Neural cells displayed process outgrowth over time in culture. Cell-seeded scaffolds were characterized in terms of their biochemical and biomechanical properties, effects on seeded neural cells, and suitability for use as 3D neural cell culture models.

  16. Programmed cell death in Laminaria japonica (Phaeophyta) tissues infected with alginic acid decomposing bacterium

    Institute of Scientific and Technical Information of China (English)

    WANG Gaoge; LIN Wei; ZHANG Lijing; YAN Xiaojun; DUAN Delin

    2004-01-01

    TdT-mediated dUTP-biotin nick end labeling (TUNEL) is a sensitive and valid method for detecting DNA cleavage in programmed cell death (PCD). Using this method, DNA cleavage was observed in Laminaria japonica sporophytic tissues, which were infected with alginic acid decomposing bacterium. It was found that DNA cleavage occurred 5 min after the infection, the fragments with 3′-OH groups of cleaved nuclear DNA increased with time of infection and spread from the infection site. Although no typical DNA ladder (200 bp/180 bp) was detected by routine agarose gel electrophoresis, the cleavage of nuclear DNA fragments of 97~48.5 kb could be detected by pulsed field gel electrophoresis (PFGE). By using CaspGLOWTM fluorescein active caspase-3 staining method, caspase-3 activity has been detected in response to the infection of alginic acid decomposing bacterium. Our results are similar to the observations in hypersensitive response (HR) of higher plant, suggesting that the rapid cell death of L. Japonica infected by alginic acid decomposing bacterium might be involved in PCD, and indicating that the occurrence of PCD is an active defense process against the pathogen's infection.

  17. Application of sodium alginate microspheres in ischemic stroke modeling in miniature pigs

    Institute of Scientific and Technical Information of China (English)

    Yongchun Cui; Like Wu; Yi Tian; Yue Tang; Liujun Jia; Aili Wu; Peng Peng; Jianzhong Yang; Hong Du; Xiaojuan Wang

    2013-01-01

    The miniature pig is an optimal animal model for studying nervous system disease because of its physiologic and pathologic features. However, the rete mirabile composed of arteries and veins at the skull base limits their application as a model of ischemic stroke by middle cerebral artery occlusion. The present study investigated the possibility of establishing an ischemic stroke model in the miniature pig by blocking the skull base retia with sodium alginate microspheres. Three Bama miniature pigs were used. Using the monitor of C-arm X-ray machine, sodium alginate aortic arch, common carotid artery, ascending pharyngeal artery and the retia. Results were evaluated using carotid arteriography, MRI, behavior observation and histology. The unilateral rete mirabile was completely blocked, resulting in disturbance in blood supply to the basal ganglia, astasia of the right hind limb and salivation. MRI and hematoxylin-eosin staining showed an evident infarction focus in the basal ganglia. These findings indicate that sodium alginate microspheres are a suitable embolic material for blocking the skull base retia in miniature pigs to establish an ischemic stroke models.

  18. Raman-based imaging uncovers the effects of alginate hydrogel implants in spinal cord injury

    Science.gov (United States)

    Galli, Roberta; Tamosaityte, Sandra; Koch, Maria; Sitoci-Ficici, Kerim H.; Later, Robert; Uckermann, Ortrud; Beiermeister, Rudolf; Gelinsky, Michael; Schackert, Gabriele; Kirsch, Matthias; Koch, Edmund; Steiner, Gerald

    2015-07-01

    The treatment of spinal cord injury by using implants that provide a permissive environment for axonal growth is in the focus of the research for regenerative therapies. Here, Raman-based label-free techniques were applied for the characterization of morphochemical properties of surgically induced spinal cord injury in the rat that received an implant of soft unfunctionalized alginate hydrogel. Raman microspectroscopy followed by chemometrics allowed mapping the different degenerative areas, while multimodal multiphoton microscopy (e.g. the combination of coherent anti-Stokes Raman scattering (CARS), endogenous two-photon fluorescence and second harmonic generation on the same platform) enabled to address the morphochemistry of the tissue at cellular level. The regions of injury, characterized by demyelination and scarring, were retrieved and the distribution of key tissue components was evaluated by Raman mapping. The alginate hydrogel was detected in the lesion up to six months after implantation and had positive effects on the nervous tissue. For instance, multimodal multiphoton microscopy complemented the results of Raman mapping, providing the micromorphology of lipid-rich tissue structures by CARS and enabling to discern lipid-rich regions that contained myelinated axons from degenerative regions characterized by myelin fragmentation and presence of foam cells. These findings demonstrate that Raman-based imaging methods provide useful information for the evaluation of alginate implant effects and have therefore the potential to contribute to new strategies for monitoring degenerative and regenerative processes induced in SCI, thereby improving the effectiveness of therapies.

  19. Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model.

    Science.gov (United States)

    Cao, Bao; Christophersen, Lars; Kolpen, Mette; Jensen, Peter Østrup; Sneppen, Kim; Høiby, Niels; Moser, Claus; Sams, Thomas

    2016-01-01

    Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100-1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm. PMID:27100887

  20. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    Science.gov (United States)

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect. PMID:26213081

  1. Radiation grafting of ionically crosslinked alginate/chitosan beads with acrylic acid for lead sorption

    International Nuclear Information System (INIS)

    Radiation-induced grafting of acrylic acid onto alginate/chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of Co-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted and un-grafted beads was performed by FTIR spectroscopy and the swelling measurements at different pHs was studied. It is found that as the pH value increases the swelling degree increases up to pH 6 but with further increase in pH value the swelling decreases. Also, it is noticed that the grafting yield increased with increase the irradiation dose. Both un-grafted and grafted alginate/chitosan beads were examined as sorbents for the removal of Pb ions from aqueous solutions. The sorption behavior of the sorbents was examined through pH, and equilibrium measurements. Grafted alginate/chitosan beads presented higher sorption capacity for Pb ions than un-grafted beads. (author)

  2. Investigation of dental alginate and agar impression materials as a brain simulant for ballistic testing.

    Science.gov (United States)

    Falland-Cheung, Lisa; Piccione, Neil; Zhao, Tianqi; Lazarjan, Milad Soltanipour; Hanlin, Suzanne; Jermy, Mark; Waddell, J Neil

    2016-06-01

    Routine forensic research into in vitro skin/skull/brain ballistic blood backspatter behavior has traditionally used gelatin at a 1:10 Water:Powder (W:P) ratio by volume as a brain simulant. A limitation of gelatin is its high elasticity compared to brain tissue. Therefore this study investigated the use of dental alginate and agar impression materials as a brain simulant for ballistic testing. Fresh deer brain, alginate (W:P ratio 91.5:8.5) and agar (W:P ratio 81:19) specimens (n=10) (11×22×33mm) were placed in transparent Perspex boxes of the same internal dimensions prior to shooting with a 0.22inch caliber high velocity air gun. Quantitative analysis to establish kinetic energy loss, vertical displacement elastic behavior and qualitative analysis to establish elasticity behavior was done via high-speed camera footage (SA5, Photron, Japan) using Photron Fastcam Viewer software (Version 3.5.1, Photron, Japan) and visual observation. Damage mechanisms and behavior were qualitatively established by observation of the materials during and after shooting. The qualitative analysis found that of the two simulant materials tested, agar behaved more like brain in terms of damage and showed similar mechanical response to brain during the passage of the projectile, in terms of energy absorption and vertical velocity displacement. In conclusion agar showed a mechanical and subsequent damage response that was similar to brain compared to alginate. PMID:27131216

  3. Rheological characterization of a gel produced using human blood plasma and alginate mixtures.

    Science.gov (United States)

    Malagón-Romero, Dionisio; Hernández, Nicolás; Cardozo, Carmen; Godoy-Silva, Rubén D

    2014-06-01

    Human blood plasma is a material used to generate tissue equivalents due to presence of fibrinogen. However, gels formed using human blood plasma has weak mechanical properties. In this study, different mixtures of sodium alginate and blood plasma were performed and evaluated. By determining ζ potential can be established the stability of the plasma-alginate mixture and by dynamic rheology can determine the most suitable parameters for the gelation of the above mixtures, when calcium chloride is used as a crosslinker. Experimental results evidence an increment in ζ potential at alginate concentrations of 0.8% and 1.6% with a resulting pseudoplastic behavior of evaluated mixtures, which described the homogenization of the mixture. On the other hand, mixtures were gelled by using aspersion of calcium chloride and characterized by dynamic rheology. Solid behavior is dominant in all range of frequency sweep test between 0.1Hz and 100Hz. Finally, the ultimate tensile strength of a gel reach 6.36938±0.24320kPa, which is enough for manual handling of the gel. Between the tasks of the gel would be used for cell entrapment, for controlled release of drugs or in the manufacture of wound dressings. PMID:24603213

  4. Effect of Diffusion on Discoloration of Congo Red by Alginate Entrapped Turnip (Brassica rapa) Peroxidase.

    Science.gov (United States)

    Ahmedi, Afaf; Abouseoud, Mahmoud; Abdeltif, Amrane; Annabelle, Couvert

    2015-01-01

    Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip "Brassica rapa" is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus Φ, and effective diffusion coefficients (D e ) of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate. PMID:25734011

  5. Flicking technique for microencapsulation of cells in calcium alginate leading to the microtissue formation.

    Science.gov (United States)

    Wong, Soon Chuan; Soon, Chin Fhong; Leong, Wai Yean; Tee, Kian Sek

    2016-03-01

    Microbeads have wide applications in biomedical engineering field that include drug delivery, encapsulation of biomolecules, tissue padding and tissue regeneration. In this paper, we report a simple, yet efficient, flicking technique to produce microcapsules of calcium alginate at a narrow distribution of size. The system consists of an infusion pump and a customised flicker that taps the syringe needle for dispersing microcapsules of sodium alginate that polymerised in the calcium chloride solution. The flow rate of the syringe pump and the velocity of the flicker were studied to achieve a well controlled and tunable size distribution of microbeads ranging from 200 to 400 μm. At a flow rate of 4 μl/min and flicking rate of 80 rpm, a narrow size distribution of microbeads were produced. Via this technique, HaCaT cells were encapsulated in calcium alginate microbeads that grown into microtissues with a size ranging from 100 to 300 μm after two weeks of culture. These microtissues could be potentially useful for pharmacological application. PMID:26878098

  6. Preparations and characterization of alginate/silver composite films: Effect of types of silver particles.

    Science.gov (United States)

    Shankar, Shiv; Wang, Long-Feng; Rhim, Jong-Whan

    2016-08-01

    Alginate-based films reinforced with different types of silver particles such as metallic silver (AgM), silver zeolite (AgZ), citrate reduced silver nanoparticles (AgNP(C)), laser ablated silver nanoparticles (AgNP(LA)), and silver nitrate (AgNO3) were prepared using a solvent casting method and the effect of silver particles on the optical, mechanical, water vapor barrier, and antimicrobial properties the composite films was evaluated. Size and shape of the silver particles were varied depending on the types of silver source and the preparation method. The alginate films incorporated with AgNP(C), AgNP(LA), and AgNO3 showed a characteristic surface plasmon resonance absorption peaks of AgNPs around 420nm. Film properties such as mechanical, optical, and water vapor barrier properties were greatly influenced by the types of AgNPs used. Alginate/AgNPs composite films except AgM and AgNP(LA) incorporated ones exhibited strong antimicrobial activity against two food-borne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. The developed films have a high potential for the application as antimicrobial food packaging films. PMID:27112867

  7. Hydroxyapatite-doped alginate beads as scaffolds for the osteoblastic differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Wang, Martha O; Bracaglia, Laura; Thompson, Joshua A; Fisher, John P

    2016-09-01

    This work investigates the role of an osteoblastic matrix component, hydroxyapatite (HA), in modular alginate scaffolds to support osteoblastic differentiation of human mesenchymal stem cells for the purpose of tissue engineered bone constructs. This system is first evaluated in a tubular perfusion bioreactor, which has been shown to improve osteoblastic differentiation over static culture conditions. HMSCs in alginate scaffolds that contain HA show increased osteoblastic gene expression compared to cells in pure alginate scaffolds, as well as significantly more matrix production and mineralization. The differentiated hMSCs and cell-laid matrix are ultimately evaluated in an in vivo site specific model. Implantation of these scaffolds with preformed matrix into the rat femoral condyle defects results in abundant bone growth and significant incorporation of the scaffold into the surrounding tissue. The developed mineralized matrix, induced in part by the HA component in the scaffold, could lead to increased tissue development in critically sized defects, and should be included in future implant strategies. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2325-2333, 2016. PMID:27129735

  8. Fabrication and optimization of alginate hydrogel constructs for use in 3D neural cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Frampton, J P; Hynd, M R; Shain, W [Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, NY 12210 (United States); Shuler, M L, E-mail: jf7674@albany.edu [Department of Biomedical Engineering, 270 Olin Hall, Cornell University, Ithaca, NY 14850 (United States)

    2011-02-15

    Two-dimensional (2D) culture systems provide useful information about many biological processes. However, some applications including tissue engineering, drug transport studies, and analysis of cell growth and dynamics are better studied using three-dimensional (3D) culture systems. 3D culture systems can potentially offer higher degrees of organization and control of cell growth environments, more physiologically relevant diffusion characteristics, and permit the formation of more extensive 3D networks of cell-cell interactions. A 3D culture system has been developed using alginate as a cell scaffold, capable of maintaining the viability and function of a variety of neural cell types. Alginate was functionalized by the covalent attachment of a variety of whole proteins and peptide epitopes selected to provide sites for cell attachment. Alginate constructs were used to entrap a variety of neural cell types including astroglioma cells, astrocytes, microglia and neurons. Neural cells displayed process outgrowth over time in culture. Cell-seeded scaffolds were characterized in terms of their biochemical and biomechanical properties, effects on seeded neural cells, and suitability for use as 3D neural cell culture models.

  9. l-Arginine grafted alginate hydrogel beads: A novel pH-sensitive system for specific protein delivery

    Directory of Open Access Journals (Sweden)

    Mohamed S. Mohy Eldin

    2015-05-01

    Full Text Available Novel pH-sensitive hydrogels based on l-arginine grafted alginate (Arg-g-Alg hydrogel beads were synthesized and utilized as a new carrier for protein delivery (BSA in specific pH media. l-arginine was grafted onto the polysaccharide backbone of virgin alginate via amine functions. Evidences of grafting of alginate were extracted from FT-IR and thermal analysis, while the morphological structure of Arg-g-Alg hydrogel beads was investigated by SEM photographs. Factors affecting on the grafting process e.g. l-arginine concentration, reaction time, reaction temperature, reaction pH, and crosslinking conditions, have been studied. Whereas, grafting efficiency of each factor was evaluated. Grafting of alginate has improved both thermal and morphological properties of Arg-g-Alg hydrogel beads. The swelling behavior of Arg-g-Alg beads was determined as a function of pH and compared with virgin calcium alginate beads. The cumulative in vitro release profiles of BSA loaded beads were studied at different pHs for simulating the physiological environments of the gastrointestinal tract. The amount of BSA released from neat alginate beads at pH 2 was almost 15% after 5 h, while the Arg-g-Alg beads at the same conditions were clearly higher than 45%, then it increased to 90% at pH 7.2. Accordingly, grafting of alginate has improved its release profile behavior particularly in acidic media. The preliminary results clearly suggested that the Arg-g-Alg hydrogel may be a potential candidate for polymeric carrier for oral delivery of protein or drugs.

  10. Effect of storage time of extended-pour and conventional alginate impressions on dimensional accuracy of casts.

    Directory of Open Access Journals (Sweden)

    Ahmad Rohanian

    2014-12-01

    Full Text Available Some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. The present study evaluated the effect of storage time on dimensional stability of three alginates: Hydrogum 5, Tropicalgin and Alginoplast.In this experimental in-vitro trial, a total of 90 alginate impressions were made from a Dentoform model using Hydrogum 5, Tropicalgin and Alginoplast alginates. The impressions were stored in a sealed plastic bag without a damp paper towel for 0, 24, 48, 72 and 120 hours and then poured with type III dental stone. Cross-arch (facial of 6 to facial of 6 on the opposite side and antero-posterior (distal of right first molar to the ipsilateral central incisor measurements were made with a digital caliper on the casts. Data were analyzed by two-way and one-way ANOVA and Tukey's post-hoc test (P<0.05.Alginate type and the pouring time significantly affected the dimensional stability of alginate impressions (both Ps<0.001. Pouring of Hydrogum 5 impressions can be delayed for up to 120 hours without significant dimensional changes. Alginoplast impressions may be poured after 72 hours, but Tropicalgin should be poured immediately and the storage time should not be more than 24 hours.Immediate pouring of alginate impressions provides the highest accuracy in reproducing the teeth and adjacent tissues; however, this study demonstrated that pouring may be delayed for up to five days using extended-pour (Hydrogum 5 alginates.

  11. Bioactive alginate coatings to control Listeria monocytogenes on cold-smoked salmon slices and fillets.

    Science.gov (United States)

    Neetoo, Hudaa; Ye, Mu; Chen, Haiqiang

    2010-01-01

    The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as CSS is a ready-to-eat product. No post-processing measures are currently available to control this pathogen in CSS. The objective of this study was to develop an effective antimicrobial edible coating containing organic salts to control the growth of L. monocytogenes in CSS slices and fillets. An in-house made formulation consisting of sodium lactate (SL, 0-2.4%) and sodium diacetate (SD, 0-0.25%) as well as 2.5% OptiForm (a commercial formulation of SL and SD) were incorporated into five edible coatings: alginate, kappa-carrageenan, pectin, gelatin or starch. The coatings were applied onto the surface of CSS slices inoculated with L. monocytogenes to an inoculum level of 500 CFU/cm(2) ( approximately 3 log CFU/g) and stored at room temperature (22 degrees C) for 6 days. Alginate coating was found to be the most effective carrier for the various antimicrobial treatments in inhibiting the growth of L. monocytogenes. In the second phase of the study, CSS slices and fillets inoculated with the pathogen at a level of 500 CFU/cm(2) were coated with alginate incorporating the in-house made and the commercial (OptiForm) SL/SD based formulations and stored for 30 days at 4 degrees C. When cold-smoked salmon slices and fillets were stored at 4 degrees C, alginate coatings supplemented with 2.4%SL/0.25%SD and the commercial product OptiForm significantly delayed the growth of L. monocytogenes during the 30-day storage with final counts reaching 4.1 and 3.3 log CFU/g (slices) and 4.4 and 3.8 log CFU/g (fillets), respectively, while the counts in their untreated counterparts were significantly higher (P<0.05) reaching 7.3 and 6.8 log CFU/g for slices and fillets, respectively. Therefore, this study demonstrates the effectiveness of using an alginate-based coating containing lactate and diacetate to control the growth of L. monocytogenes to enhance the microbiological safety of

  12. Preparation of microfibrillated cellulose/chitosan-benzalkonium chloride biocomposite for enhancing antibacterium and strength of sodium alginate films.

    Science.gov (United States)

    Liu, Kai; Lin, Xinxing; Chen, Lihui; Huang, Liulian; Cao, Shilin; Wang, Huangwei

    2013-07-01

    The nonantibacterial and low strength properties of sodium alginate films negatively impact their application for food packaging. In order to improve these properties, a novel chitosan-benzalkonium chloride (C-BC) complex was prepared by ionic gelation using tripolyphosphate (TPP) as a coagulant, and a biocomposite obtained through the adsorption of C-BC complex on microfibrillated cellulose, MFC/C-BC, was then incorporated into a sodium alginate film. The TEM image showed that the C-BC nanoparticles were spherical in shape with a diameter of about 30 nm, and the adsorption equilibrium time of these nanoparticles on the surface of MFC was estimated to be 6 min under the driving forces of hydrogen bonds and electrostatic interactions. According to the disc diffusion method, the MFC/C-BC biocomposite-incorporated sodium alginate film exhibited remarkable antibacterial activity against Staphylococcus aureus and certain antibacterial activity against Escherichia coli . The strength tests indicated that the tensile strength of the composite sodium alginate film increased about 225% when the loading of MFC/C-BC biocomposite was 10 wt %. These results suggested that the MFC/C-BC biocomposite-incorporated sodium alginate film with excellent antibacterial and strength properties would be a promising material for food packaging, and the MFC/C-BC may also be a potential multifunctional biocomposite for other biodegradable materials. PMID:23750871

  13. Enhanced cyclability of sulfur cathodes in lithium-sulfur batteries with Na-alginate as a binder

    Institute of Scientific and Technical Information of China (English)

    Weizhai; Bao; Zhian; Zhang; Yongqing; Gan; Xiwen; Wang; Jie; Lia

    2013-01-01

    Na-alginate as a binder in an aqueous solvent has been applied in the preparation of sulfur cathodes for lithium-sulfur batteries.Their electrochemical performances have been investigated by a charge-discharge cycle test and electrochemical impedance spectroscopy (EIS).The EIS tests indicated that the alginate sulfur cathode had lower resistance and better kinetic characteristics than those of the poly (vinylidene fluoride) (PVDF) sulfur cathode using PVDF as a binder in a N-methy-2-pyrrolidone (NMP) solvent.The charge-discharge tests showed that the discharge capacity and the capacity retention rate of Na-alginate sulfur cathode were 508 mAh·g-1and 65.4% at the 50th cycle with a current density of 335 mA·g-1.Compared with PVDF sulfur cathode,the alginate sulfur cathode showed a remarkably better cycle performance.These results show that the alginate binder has promising potential for lithium-sulfur battery applications.

  14. A comparative assessment of the potential use of alginates and dietary calcium manipulation as countermeasures to reduce the transfer of radiostrontium to the milk of dairy animals

    International Nuclear Information System (INIS)

    The potential of using different alginates or supplementary calcium as feed-additives to reduce the transfer of ingested radiostrontium to milk was assessed in dairy cattle fed a haylage/concentrate diet. The feed-additives compared were: calcium alginate (4% by dry matter), sodium alginate (4% by dry matter) and four levels of supplementation with CaCO3. Both alginates reduced the transfer of radiostrontium to milk by 30-40% without effecting diet palatability. However, the high present cost of alginates precludes their use as countermeasures. Dietary calcium supplementation reduced the transfer of 85Sr to milk broadly in agreement with previous predictions. From data relevant to dairy cattle in the United Kingdom it is suggested that dietary calcium intake could be doubled without exceeding recommended maximum intakes, thus decreasing the transfer of radiostrontium to milk by approximately 50%

  15. Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15

    International Nuclear Information System (INIS)

    The crystallization and preliminary X-ray characterization of a family PL-15 exotype alginate lyase are presented. Almost all alginate lyases depolymerize alginate in an endolytical fashion via a β-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P21 and diffracted to 2.8 Å resolution, with unit-cell parameters a = 107.7, b = 108.3, c = 149.5 Å, β = 91.5°

  16. A non-destructive culturing and cell sorting method for cardiomyocytes and neurons using a double alginate layer.

    Directory of Open Access Journals (Sweden)

    Hideyuki Terazono

    Full Text Available A non-destructive method of collecting cultured cells after identifying their in situ functional characteristics is proposed. In this method, cells are cultivated on an alginate layer in a culture dish and released by spot application of a calcium chelate buffer that locally melts the alginate layer and enables the collection of cultured cells at the single-cell level. Primary hippocampal neurons, beating human embryonic stem (hES cell-derived cardiomyocytes, and beating hES cell-derived cardiomyocyte clusters cultivated on an alginate layer were successfully released and collected with a micropipette. The collected cells were recultured while maintaining their physiological function, including beating, and elongated neurites. These results suggest that the proposed method may eventually facilitate the transplantation of ES- or iPS-derived cardiomyocytes and neurons differentiated in culture.

  17. Continuous ethanol fermentation at 45 C using Kluyveromyces marxianus IMB3 immobilized in Calcium alginate and kissiris

    Energy Technology Data Exchange (ETDEWEB)

    Love, G.; Gough, S.; Brady, D.; Barron, N.; Nigam, P.; Marchant, R.; McHale, A.P. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom); Singh, D. [Microbiology Dept., Haryana Agricultural University, Hisar (India)

    1998-03-01

    The thermotolerant ethanol-producing yeast strain Kluyveromyces marxianus IMB3 was immobilized in calcium alginate and a 1:1 mixture of calcium alginate and the porous volcanic mineral, kissiris. Immobilized preparations were placed in fixed-bed column bioreactors and continuous ethanol production by systems containing both immobilized preparations was examined at 45 C with a 100 g/l glucose feed. The effect of residence time on product concentration, bioreactor efficiency and volumetric productivities have been examined and these were all higher in systems containing the alginate/kissiris mixed immobilization matrix. Maximum ethanol concentrations produced by the continuous system ranged between 46 and 48 g/l representing efficiencies of 90-94%. (orig.) With 1 tab., 13 refs.

  18. Ethanol production at 45 C using preparations of Kluyveromyces marxianus IMB3 immobilized in calcium alginate and kissiris

    Energy Technology Data Exchange (ETDEWEB)

    Love, G. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom); Nigam, P. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom); Barron, N. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom); Singh, D. [Microbiology Dept., Haryana Agricultural University, Hisar (India); Marchant, R. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom); McHale, A.P. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster (United Kingdom)

    1996-10-01

    The thermotolerant yeast, K. marxianus IMB3, was grown in free and immobilized states in batch-fed culture at 45 C and ethanol production was examined over a 61-day period. The organism was grown in the free state, in the free state with mineral kissiris, immobilized in calcium alginate and immobilized in calcium alginate together with kissiris. Initially, reactors were fed every two days with 10% (w/v) glucose-containing media and no significant difference in ethanol production was observed. In subsequent refeeding experiments, reactors were re-fed every two days with 15% (w/v) sucrose-containing media. Although overall ethanol concentrations decreased, production in the immobilized systems was higher. In the final stages fermentations were re-fed every 3 days and although overall ethanol production decreased further, production remained highest in the systems containing calcium alginate and kissiris. (orig.). With 1 tab.

  19. Mutational Analyses of Glucose Dehydrogenase and Glucose-6-Phosphate Dehydrogenase Genes in Pseudomonas fluorescens Reveal Their Effects on Growth and Alginate Production

    Science.gov (United States)

    Maleki, Susan; Mærk, Mali; Valla, Svein

    2015-01-01

    The biosynthesis of alginate has been studied extensively due to the importance of this polymer in medicine and industry. Alginate is synthesized from fructose-6-phosphate and thus competes with the central carbon metabolism for this metabolite. The alginate-producing bacterium Pseudomonas fluorescens relies on the Entner-Doudoroff and pentose phosphate pathways for glucose metabolism, and these pathways are also important for the metabolism of fructose and glycerol. In the present study, the impact of key carbohydrate metabolism enzymes on growth and alginate synthesis was investigated in P. fluorescens. Mutants defective in glucose-6-phosphate dehydrogenase isoenzymes (Zwf-1 and Zwf-2) or glucose dehydrogenase (Gcd) were evaluated using media containing glucose, fructose, or glycerol. Zwf-1 was shown to be the most important glucose-6-phosphate dehydrogenase for catabolism. Both Zwf enzymes preferred NADP as a coenzyme, although NAD was also accepted. Only Zwf-2 was active in the presence of 3 mM ATP, and then only with NADP as a coenzyme, indicating an anabolic role for this isoenzyme. Disruption of zwf-1 resulted in increased alginate production when glycerol was used as the carbon source, possibly due to decreased flux through the Entner-Doudoroff pathway rendering more fructose-6-phosphate available for alginate biosynthesis. In alginate-producing cells grown on glucose, disruption of gcd increased both cell numbers and alginate production levels, while this mutation had no positive effect on growth in a non-alginate-producing strain. A possible explanation is that alginate synthesis might function as a sink for surplus hexose phosphates that could otherwise be detrimental to the cell. PMID:25746989

  20. Characterization of free and alginate-polylysine-alginate microencapsulated Erwinia herbicola for the conversion of ammonia, pyruvate, and phenol into L-tyrosine

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd-George, I.; Chang, T.M.S. [McGill Univ., Montreal, Quebec (Canada)

    1995-12-20

    The whole cell tyrosine phenol-lyase activity of Erwinia herbicola was microencapsulated. The authors studied the use of this for the conversion of ammonia and pyruvate along with phenol or catechol, respectively, into L-tyrosine or dihydroxyphenyl-L-alanine (L-dopa). The reactions are relevant to the development of new methods for the production of L-tyrosine and L-dopa. The growth of E. herbicola at temperatures from 22 C to 32 C is stable, since at these temperatures the cells grow up to the stationary phase and remain there for at least 10 h. At 37 C the cells grow rapidly, but they also enter the death phase rapidly. There is only limited growth of E. herbicola at 42 C. Whole cells of E. herbicola were encapsulated within alginate-polylysine-alginate microcapsules (916 {+-} 100 {micro}m, mean {+-} std. dev.). The TPL activity of the cells catalyzed the production of L-tyrosine or dihydroxyphenol-L-alanine (L-dopa) from ammonia, pyruvate, and phenol or catechol, respectively. In the production of tyrosine, an integrated equation based on an ordered ter-uni rapid equilibrium mechanism can be used to find the kinetic parameters of TPL. In an adequately stirred system, the apparent values of the kinetic parameters of whole cell TPL are equal whether the cells are free or encapsulated. The apparent K{sub M} of tyrosine varies with the amount of whole cells in the system, ranging from 0.2 to 0.3 mM. The apparent K{sub M} for phenol is 0.5 mM. The apparent K{sub M} values for pyruvate and ammonia are an order of magnitude greater for whole cells than they are for the cell free enzyme.

  1. Hierarchical mesoporous bioactive glass/alginate composite scaffolds fabricated by three-dimensional plotting for bone tissue engineering

    International Nuclear Information System (INIS)

    Constructing bioactive scaffolds with controllable architecture for bone tissue engineering and drug delivery still maintains a significant challenge. In this study, we have developed a composite material consisting of mesoporous bioactive glass (MBG) and concentrated alginate pastes for fabrication of hierarchical scaffolds by 3D plotting. The scaffold structure contains well-ordered nano-channels, micropores as well as controllable macropores beneficial for bone tissue engineering applications and drug delivery. The structural architecture of the scaffolds has been optimized by efficient designing of the plotting coordination. The effects of MBG on mechanical strength, apatite mineralization, cytocompatibility and drug delivery properties of the composite scaffolds have been systematically studied. Transmission electron microscopy, scanning electron microscopy and energy-dispersive spectrometry were used to characterize composition and microstructure of the composite scaffolds. The MBG/alginate pastes showed good processability in the 3D plotting process, in which stable MBG/alginate composite scaffolds with controllable architecture can be prepared. The incorporation of MBG particles significantly improved the mechanical properties and apatite-mineralization ability of alginate scaffolds as well as enhanced the attachment and alkaline phosphatase activity of human bone marrow-derived mesenchymal stem cells cultivated onto the scaffolds. Dexamethasone, used as a model drug, can be efficiently loaded in MBG particles and then incorporated into alginate scaffolds resulting in a more sustained release as a function of the MBG content. Our results have indicated that 3D-plotted MBG incorporated alginate scaffolds with well-ordered nano-pores, controllable large pores, and significantly improved physicochemical, biological and drug-delivery properties could be a platform for bone tissue engineering. (paper)

  2. Produção de alginato por microrganismos Alginate production by microorganisms

    Directory of Open Access Journals (Sweden)

    José Miguel Müller

    2011-01-01

    Full Text Available O alginato é um copolímero linear constituído de unidades de ácidos α-L-gulurônicos e β-D-manurônicos e é extensamente utilizado devido as suas propriedades espessantes, estabilizantes e gelificantes. Estas características fazem com que este biopolímero encontre aplicações na indústria de alimentos, na indústria têxtil e de papel, em cosméticos e na área farmacêutica e médica. Atualmente para este conjunto de aplicações sua principal fonte são algas marrons, entretanto, o alginato pode ser obtido a partir de biossíntese, utilizando-se microrganismos do gênero Pseudomonas e Azotobacter. A produção bacteriana de alginato apresenta-se como uma alternativa interessante e sua produção por microrganismos, além de possibilitar a produção de biopolímeros de alta qualidade com características específicas e pré-determinadas, irá diminuir o impacto ambiental nas regiões em que as algas marinhas das quais é extraído são coletadas. Nos últimos anos, vários estudos relacionados à produção de alginato por microrganismos foram realizados com o objetivo de avaliar sua produção e rota metabólica de biossíntese, para caracterizar o material produzido e para determinar as potencialidades de aplicação deste novo material. O rápido desenvolvimento de aplicações do alginato na área médica e farmacêutica, bem como a descoberta de propriedades imunológicas únicas deste material tem aumentado o interesse no desenvolvimento de processos para produzi-lo. Neste artigo são abordados aspectos relacionados à produção e as características do alginato bacteriano e também reportadas às potencialidades e aplicações inovadoras nas quais este material vem sendo utilizado.Alginate is a linear copolymer consisting of units of α-L-guluronic and β-D-mannuronic acid which is widely used due to its thickening, stabilizing and gelling properties. These characteristics mean that it has many applications in the food

  3. Fabrication of engineered heart tissue grafts from alginate/collagen barium composite microbeads

    International Nuclear Information System (INIS)

    Cardiac tissue engineering holds great promise for the treatment of myocardial infarction. However, insufficient cell migration into the scaffolds used and inflammatory reactions due to scaffold biodegradation remain as issues to be addressed. Engineered heart tissue (EHT) grafts fabricated by means of a cell encapsulation technique provide cells with a tissue-like environment, thereby potentially enhancing cellular processes such as migration, proliferation, and differentiation, and tissue regeneration. This paper presents a study on the fabrication and characterization of EHT grafts from novel alginate/collagen composite microbeads by means of cell encapsulation. Specifically, the microbeads were fabricated from alginate and collagen by barium ion cross-linking, with neonatal rat cardiomyocytes encapsulated in the composite microbeads during the fabrication of the EHT grafts. To evaluate the suitablity of these EHT grafts for heart muscle repair, the growth of cardiac cells in the microbeads was examined by means of confocal microscopy and staining with DAPI and F-actin. The EHT grafts were analyzed by scanning electron microscopy and transmission electron microscopy, and the contractile function of the EHT grafts monitored using a digital video camera at different time points. The results show the proliferation of cardiac cells in the microbeads and formation of interconnected multilayer heart-like tissues, the presence of well-organized and dense cell structures, the presence of intercalated discs and spaced Z lines, and the spontaneous synchronized contractility of EHT grafts (at a rate of 20-30 beats min-1 after two weeks in culture). Taken together, these observations demonstrate that the novel alginate/collagen composite microbeads can provide a tissue-like microenvironment for cardiomyocytes that is suitable for fabricating native heart-like tissues.

  4. In vivo bioengineered ovarian tumors based on collagen, matrigel, alginate and agarose hydrogels: a comparative study

    International Nuclear Information System (INIS)

    Scaffold-based tumor engineering is rapidly evolving the study of cancer progression. However, the effects of scaffolds and environment on tumor formation have seldom been investigated. In this study, four types of injectable hydrogels, namely, collagen type I, Matrigel, alginate and agarose gels, were loaded with human ovarian cancer SKOV3 cells and then injected into nude mice subcutaneously. The growth of the tumors in vitro was also investigated. After four weeks, the specimens were harvested and analyzed. We found that tumor formation by SKOV3 cells was best supported by collagen, followed by Matrigel, alginate, control (without scaffold) and agarose in vivo. The collagen I group exhibited a larger tumor volume with increased neovascularization and increased necrosis compared with the other materials. Further, increased MMP activity, upregulated expression of laminin and fibronectin and higher levels of HIF-1α and VEGF-A in the collagen group revealed that the engineered tumor is closer to human ovarian carcinoma. In order, collagen, Matrigel, alginate, control (without scaffold) and agarose exhibited decreases in tumor formation. All evidence indicated that the in vivo engineered tumor is scaffold-dependent. Bioactive hydrogels are superior to inert hydrogels at promoting tumor regeneration. In particular, biomimetic hydrogels are advantageous because they provide a microenvironment that mimics the ECM of natural tumors. On the other hand, typical features of cancer cells and the expression of genes related to cancer malignancy were far less similar to the natural tumor in vitro, which indicated the importance of culture environment in vivo. Superior to the in vitro culture, nude mice can be considered satisfactory in vivo ‘bioreactors’ for the screening of favorable cell vehicles for tumor engineering in vitro. (paper)

  5. Production of BCG alginate-PLL microcapsules by emulsification/internal gelation.

    Science.gov (United States)

    Esquisabel, A; Hernández, R M; Igartua, M; Gascón, A R; Calvo, B; Pedraz, J L

    1997-01-01

    A biocompatible emulsification method for microencapsulation of live cells and enzymes within a calcium alginate matrix applied to Bacillus Calmette-Guérin (BCG) has been developed. Small-diameter alginate beads (microcapsules) were formed via internal gelation of an alginate solution emulsified within vegetable oil. Five different oils (sesame, sweet almond, perhydrosqualene, camomile and jojoba) were used. The rheological analysis of the oils showed a Newtonian behaviour, with viscosities = 30.0, 37.7, 51.2, 59.3 and 67.1 mPa.s for perhydrosqualene, jojoba, camomile, sesame and sweet almond oil respectively. The particle size of the microcapsules obtained ranged from 30.3 microns for the microcapsules prepared with sweet almond oil to 57.0 microns for those made with perhydrosqualene. The mean particle diameter obtained was found to be dependent on the viscosity of the oil employed, according to the equation: phi (micron) = 76.6-0.628 eta (mPa.s) (r2 = 0.943). The encapsulated BCG was identified by the Difco TB stain set K, followed by observation under optical microscopy. Freeze-drying of the microcapsules was carried out to ensure their stability during storage. Two batches of microcapsules (those prepared with sesame and jojoba oil) and four types of cryoprotectors (glucose, trehalose, mannitol and sorbitol), at three concentration levels (5, 10 and 20% w/v) were studied. The parameters evaluated were particle size, physical appearance, reconstitution of lyophilizates and microscopical evaluation. For both batches of microcapsules the best results were obtained with trehalose 5%, showing particle sizes of 42.1 microns in the case of the microcapsules prepared with sesame oil, and of 45.3 microns for those prepared with jojoba. PMID:9292438

  6. Fabrication of engineered heart tissue grafts from alginate/collagen barium composite microbeads

    Energy Technology Data Exchange (ETDEWEB)

    Bai, X P; Zheng, H X; Fang, R; Wang, T R; Li, Y; Tian, W M [Department of Life Science and Engineering, Harbin Institute of Technology, Harbin, 150080 (China); Hou, X L [The Fourth Affiliated Hospital of Harbin Medical University, Harbin, 150001 (China); Chen, X B, E-mail: tianweiming@gmail.com [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada)

    2011-08-15

    Cardiac tissue engineering holds great promise for the treatment of myocardial infarction. However, insufficient cell migration into the scaffolds used and inflammatory reactions due to scaffold biodegradation remain as issues to be addressed. Engineered heart tissue (EHT) grafts fabricated by means of a cell encapsulation technique provide cells with a tissue-like environment, thereby potentially enhancing cellular processes such as migration, proliferation, and differentiation, and tissue regeneration. This paper presents a study on the fabrication and characterization of EHT grafts from novel alginate/collagen composite microbeads by means of cell encapsulation. Specifically, the microbeads were fabricated from alginate and collagen by barium ion cross-linking, with neonatal rat cardiomyocytes encapsulated in the composite microbeads during the fabrication of the EHT grafts. To evaluate the suitablity of these EHT grafts for heart muscle repair, the growth of cardiac cells in the microbeads was examined by means of confocal microscopy and staining with DAPI and F-actin. The EHT grafts were analyzed by scanning electron microscopy and transmission electron microscopy, and the contractile function of the EHT grafts monitored using a digital video camera at different time points. The results show the proliferation of cardiac cells in the microbeads and formation of interconnected multilayer heart-like tissues, the presence of well-organized and dense cell structures, the presence of intercalated discs and spaced Z lines, and the spontaneous synchronized contractility of EHT grafts (at a rate of 20-30 beats min{sup -1} after two weeks in culture). Taken together, these observations demonstrate that the novel alginate/collagen composite microbeads can provide a tissue-like microenvironment for cardiomyocytes that is suitable for fabricating native heart-like tissues.

  7. Modeling the controllable pH-responsive swelling and pore size of networked alginate based biomaterials.

    Science.gov (United States)

    Chan, Ariel W; Neufeld, Ronald J

    2009-10-01

    Semisynthetic network alginate polymer (SNAP), synthesized by acetalization of linear alginate with di-aldehyde, is a pH-responsive tetrafunctionally linked 3D gel network, and has potential application in oral delivery of protein therapeutics and active biologicals, and as tissue bioscaffold for regenerative medicine. A constitutive polyelectrolyte gel model based on non-Gaussian polymer elasticity, Flory-Huggins liquid lattice theory, and non-ideal Donnan membrane equilibria was derived, to describe SNAP gel swelling in dilute and ionic solutions containing uni-univalent, uni-bivalent, bi-univalent or bi-bi-valent electrolyte solutions. Flory-Huggins interaction parameters as a function of ionic strength and characteristic ratio of alginates of various molecular weights were determined experimentally to numerically predict SNAP hydrogel swelling. SNAP hydrogel swells pronouncedly to 1000 times in dilute solution, compared to its compact polymer volume, while behaving as a neutral polymer with limited swelling in high ionic strength or low pH solutions. The derived model accurately describes the pH-responsive swelling of SNAP hydrogel in acid and alkaline solutions of wide range of ionic strength. The pore sizes of the synthesized SNAP hydrogels of various crosslink densities were estimated from the derived model to be in the range of 30-450 nm which were comparable to that measured by thermoporometry, and diffusion of bovine serum albumin. The derived equilibrium swelling model can characterize hydrogel structure such as molecular weight between crosslinks and crosslinking density, or can be used as predictive model for swelling, pore size and mechanical properties if gel structural information is known, and can potentially be applied to other point-link network polyelectrolytes such as hyaluronic acid gel. PMID:19660810

  8. Muscle Tissue Engineering Using Gingival Mesenchymal Stem Cells Encapsulated in Alginate Hydrogels Containing Multiple Growth Factors.

    Science.gov (United States)

    Ansari, Sahar; Chen, Chider; Xu, Xingtian; Annabi, Nasim; Zadeh, Homayoun H; Wu, Benjamin M; Khademhosseini, Ali; Shi, Songtao; Moshaverinia, Alireza

    2016-06-01

    Repair and regeneration of muscle tissue following traumatic injuries or muscle diseases often presents a challenging clinical situation. If a significant amount of tissue is lost the native regenerative potential of skeletal muscle will not be able to grow to fill the defect site completely. Dental-derived mesenchymal stem cells (MSCs) in combination with appropriate scaffold material, present an advantageous alternative therapeutic option for muscle tissue engineering in comparison to current treatment modalities available. To date, there has been no report on application of gingival mesenchymal stem cells (GMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of the current study were to develop an injectable 3D RGD-coupled alginate scaffold with multiple growth factor delivery capacity for encapsulating GMSCs, and to evaluate the capacity of encapsulated GMSCs to differentiate into myogenic tissue in vitro and in vivo where encapsulated GMSCs were transplanted subcutaneously into immunocompromised mice. The results demonstrate that after 4 weeks of differentiation in vitro, GMSCs as well as the positive control human bone marrow mesenchymal stem cells (hBMMSCs) exhibited muscle cell-like morphology with high levels of mRNA expression for gene markers related to muscle regeneration (MyoD, Myf5, and MyoG) via qPCR measurement. Our quantitative PCR analyzes revealed that the stiffness of the RGD-coupled alginate regulates the myogenic differentiation of encapsulated GMSCs. Histological and immunohistochemical/fluorescence staining for protein markers specific for myogenic tissue confirmed muscle regeneration in subcutaneous transplantation in our in vivo animal model. GMSCs showed significantly greater capacity for myogenic regeneration in comparison to hBMMSCs (p < 0.05). Altogether, our findings confirmed that GMSCs encapsulated in RGD-modified alginate hydrogel with multiple growth factor delivery capacity is a promising

  9. Heme Iron Release from Alginate Beads at In Vitro Simulated Gastrointestinal Conditions.

    Science.gov (United States)

    Valenzuela, Carolina; Hernández, Valesca; Morales, María Sol; Pizarro, Fernando

    2016-07-01

    Heme iron (Fe) release from alginate beads at in vitro simulated gastrointestinal conditions for potential use as oral heme Fe supplement was studied. Five beads at different ratios of sodium alginate (SA)-to-spray-dried bovine blood cells (SDBC) with weight ratios of 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 (w/w) were prepared. Release characteristics of these beads were investigated at in vitro simulated gastrointestinal conditions. Release media pH strongly influenced the controlled Fe release from the beads. The heme Fe-beads in simulated gastric fluid (pH 2) remained in a shrinkage state and Fe release was low: 25.8, 21.1, 11.6, 12.1, and 12.0 % for 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 ratios, respectively. Proportion and amount of Fe released by 1:1.25 and 1:2.5 ratios was higher than the other ratios. The heme Fe-beads swelled and dissociated in simulated intestinal fluid (pH 6), releasing three-fourths of the Fe in 200 min. The morphology studies showed that Fe release followed formation of pores in the alginate matrix, generating erosion of the beads and complete disintegration after 75 and 200 min of gastric and intestinal incubation, respectively. These results indicate that heme Fe-beads may be useful for oral delivery of heme Fe supplement. PMID:26610684

  10. Production of Ethanol from Beet Molasses by Ca-Alginate Immobilized Yeast Cells in a Packed-Bed Bioreactor

    OpenAIRE

    GÖKSUNGUR, Yekta; ZORLU, Neşe

    2001-01-01

    The continuous production of ethanol from beet molasses by Ca-alginate immobilized Saccharomyces cerevisiae in a packed-bed bioreactor was investigated. The temperature was maintained at 30°C and the dilution rate was 0.22 h-1. Maximum ethanol (4.62%), theoretical yield (82.9%) and volumetric productivity (10.16 gl-1h-1) were obtained from the beet molasses medium containing 10.90% total sugar with 2.0-2.4 mm diameter beads prepared from 2% (w/v) sodium alginate solution. At higher substrate ...

  11. Study of Sorption Equilibrium of Biopolymers Alginic Acid and Xanthan with C.I. Disperse Yellow 54

    OpenAIRE

    Juan Antonio Lozano-Álvarez; Juan Jáuregui-Rincón; Guillermo Mendoza-Díaz; Refugio Rodríguez-Vázquez; Claudio Frausto-Reyes

    2009-01-01

    Disperse yellow 54 (DY54) was adsorbed onto two biopolymers, alginic acid and xanthan. The adsorption isotherms for the biopolymer-DY54 system showed that the adsorption mechanism can best be described by Zimm-Bragg theory. UV-Visible, FT-IR and MicroRaman studies suggest that DY54 is bounded to both biopolymers alginic acid and xanthan through hydrogen bonding. Keto group of dye and hydroxyl groups of sugar residues from two polysaccharides were the principal functional groups involved in so...

  12. Growth and by-product profiles of Kluyveromyces marxianus cells immobilized in foamed alginate.

    Science.gov (United States)

    Wilkowska, Agnieszka; Kregiel, Dorota; Guneser, Onur; Karagul Yuceer, Yonca

    2015-01-01

    The aim of this research was to study how the yeast cell immobilization technique influences the growth and fermentation profiles of Kluyveromyces marxianus cultivated on apple/chokeberry and apple/cranberry pomaces. Encapsulation of the cells was performed by droplet formation from a foamed alginate solution. The growth and metabolic profiles were evaluated for both free and immobilized cells. Culture media with fruit waste produced good growth of free as well as immobilized yeast cells. The fermentation profiles of K. marxianus were different with each waste material. The most varied aroma profiles were noted for immobilized yeast cultivated on apple/chokeberry pomace. PMID:25277269

  13. The Effect of Chitosan and Sodium Alginate on the Root Growth and Enzyme Activity of Soybean

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The resaerch examined the effect of the two oceanic materials as coating materials on the soybean growth. The results showed chitosan and sodium alginate seed coating can enhance the growth of seedling root,increase the nodule mumber,root activity and the growth of underground. The suggested coating ratios were 0. 5~ 1.0g/kgseed,the same as chitosan. The two materials could increase the contents of CAT and NR in soybean leaves ,decrease the contents of POD in soybean leaves.

  14. NMR imaging of heavy metal absorption in alginate, immobilized cells, and kombu algal biosorbents.

    Science.gov (United States)

    Nestle, N F; Kimmich, R

    1996-09-01

    In this contribution, an NMR imaging study of heavy metal absorption in alginate, immobilized-cell biosorbents, and kombu (Laminaria japonica) algal biomass is presented. This method provides the good possibility of directly monitoring the time evolution of the spatial distribution of the ions in the materials. From these results, we demonstrate that rare earth ions are absorbed with a steep reaction front that can be described very well with a modified shrinking core model, while copper ions are absorbed with a more diffuse front. PMID:18629817

  15. Effect of bromocriptine alginate nanocomposite (BANC) on a transgenic Drosophila model of Parkinson's disease

    OpenAIRE

    Yasir Hasan Siddique; Wasi Khan; Ambreen Fatima; Smita Jyoti; Saba Khanam; Falaq Naz; De Rahul; Fahad Ali; Braj Raj Singh; Alim Hussain Naqvi

    2016-01-01

    ABSTRACT The effect of bromocriptine, a dopamine agonist, administered in the form of bromocriptine alginate nanocomposite (BANC) was studied on Parkinson's disease (PD) model flies. The synthesized BANC was subject to characterization and, at a final concentration of 0.5, 1.0 and 1.5 µM, was mixed in diet. The PD flies were allowed to feed on it for 24 days. A significant dose-dependent delay in the loss of climbing activity and activity pattern was observed in PD flies exposed to 0.5, 1.0 a...

  16. PREPARATION AND EVALUATION OF SUSTAINED RELEASE MICROSPHERE OF NORFLOXACIN USING SODIUM ALGINATE

    Directory of Open Access Journals (Sweden)

    Raja Chakraverty

    2012-01-01

    Full Text Available Oral controlled drug delivery systems represent the most popular form of sustained drug delivery systems for the obvious advantages of oral route of drug administration. Such systems release the drug with constant or variable release rates. The oral controlled release systems shows a typical pattern of drug release in which the drug concentration is maintained in the therapeutic window for a prolonged period of time (sustained release, thereby ensuring sustained therapeutic action. They are used as single dosage form. Present work involves preparation and evaluation of sustained release of microspheres of Norfloxacin employing sodium alginate as natural polymer. The technique employed for microencapsulation of the drug is ionotropic gelation.

  17. The effect of soluble alginate and calcium on {beta}-galactosidase activity produced by the thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus imb3

    Energy Technology Data Exchange (ETDEWEB)

    Brady, D.; Logan, S.R.; McHale, A.P. [Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, Co. Londonderry, BT52 1SA (United Kingdom)

    1998-02-01

    Since it has previously been demonstrated that ethanol production by the thermotolerant yeast strain, Kluyveromyces marxianus IMB3 is more efficient in calcium alginate-based immobilization systems during growth on lactose-containing media, it was decided to examine the separate effects of soluble alginate and free calcium on the {beta}-galactosidase activity produced by that organism. It was found that the presence of Ca{sup 2+} significantly increased the thermal stability of the activity at 45 C, although the pH and temperature optima remained the same in the presence and absence of that cation. It was also found that the presence of 2% (w/v) sodium alginate (soluble) had a very limited positive effect on the thermal stability of the enzyme at 45 C, although it was found that activity was very significantly stimulated at that temperature. The activity was found to have an enhanced thermal stability at 30 C in the presence of sodium alginate. The presence of sodium alginate in assay mixtures had no significant effect on the Km of the activity for the substrate o-nitrophenyl-{beta}-D-galactoside. The results observed in the presence of either free calcium or soluble alginate may at least partially explain enhanced ethanol production by this microorganism in alginate-based immobilization systems. (orig.) With 2 figs., 14 refs.

  18. Alginate based bilayer hydrocolloid films as potential slow-release modern wound dressing.

    Science.gov (United States)

    Thu, Hnin-Ei; Zulfakar, Mohd Hanif; Ng, Shiow-Fern

    2012-09-15

    The aims of this research were to develop a novel bilayer hydrocolloid film based on alginate and to investigate its potential as slow-release wound healing vehicle. The bilayer is composed of an upper layer impregnated with model drug (ibuprofen) and a drug-free lower layer, which acted as a rate-controlling membrane. The thickness uniformity, solvent loss, moisture vapour transmission rate (MVTR), hydration rate, morphology, rheology, mechanical properties, in vitro drug release and in vivo wound healing profiles were investigated. A smooth bilayer film with two homogenous distinct layers was produced. The characterisation results showed that bilayer has superior mechanical and rheological properties than the single layer films. The bilayers also showed low MVTR, slower hydration rate and lower drug flux in vitro compared to single layer inferring that bilayer may be useful for treating low suppurating wounds and suitable for slow release application on wound surfaces. The bilayers also provided a significant higher healing rate in vivo, with well-formed epidermis with faster granulation tissue formation when compared to the controls. In conclusions, a novel alginate-based bilayer hydrocolloid film was developed and results suggested that they can be exploited as slow-release wound dressings. PMID:22643226

  19. Calcium alginate gel capsules loaded with inhibitor for corrosion protection of downhole tube in oilfields

    International Nuclear Information System (INIS)

    Highlights: • Calcium alginate gel capsules loaded with inhibitor were prepared by piercing-solidifying method. • Introduced heavy additive accelerates the sinking of capsules loaded with inhibitor. • Capsules gradually release inhibitor during its sinking to the bottom of oilwell. • Tubes from top to bottom in oilwell were effectively protected by inhibitor. - Abstract: Calcium alginate gel (Alg-Ca2+) capsules loaded with inhibitor and heavy additive were prepared by a piercing-solidifying method. The releasing process of inhibitor together with their inhibitive effect on P110 steel in CO2-saturated 3.5 wt.% NaCl aqueous solution was investigated by ultraviolet–visible spectrophotometer, scanning electron microscopy, electrochemical impedance spectroscopy. Our experiments revealed that the synthesized capsules can gradually release inhibitors during their sinking process, and effectively prevent the tube in oilwell from corrosion. Introducing appropriate amount of heavy additive BaSO4 into the inhibitor-loaded capsules facilitates their sinking processes and corrosion protection performance

  20. Oxygen sensing glucose biosensors based on alginate nano-micro systems

    Science.gov (United States)

    Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

    2014-04-01

    Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10μm were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

  1. Properties of Lactobacillus reuteri chitosan-calcium-alginate encapsulation under simulated gastrointestinal conditions.

    Science.gov (United States)

    Huang, Hui-Ying; Tang, Yi-Ju; King, V An-Erl; Chou, Jen-Wei; Tsen, Jen-Horng

    2015-03-01

    The protective effects of encapsulation on the survival of Lactobacillus reuteri and the retention of the bacterium's probiotic properties under simulated gastrointestinal conditions were investigated. Viable counts and the remaining probiotic properties of calcium (Ca)-alginate encapsulated (A group), chitosan-Ca-alginate encapsulated (CA group), and unencapsulated, free L. reuteri (F group) were determined. Encapsulation improved the survival of L. reuteri subjected to simulated gastrointestinal conditions, with the greatest protective effect achieved in the CA group. The degree of cell membrane injury increased with increasing bile salt concentrations at constant pH, but the extent of injury was less in the encapsulated than in the free cells. Adherence rates were, in descending order: CA (0.524%)>A (0.360%)>F (0.275%). Lactobacillus reuteri cells retained their antagonistic activity toward Listeria monocytogenes even after incubation of the lactobacilli under simulated gastrointestinal conditions. Displacement of the pathogen by cells released from either of the encapsulation matrices was higher than that by free cells. The safety of L. reuteri was demonstrated in an in vitro invasion assay. PMID:26415668

  2. Immobilization of rapeseed press-cake in an alginate matrix for the sorption of atrazine.

    Science.gov (United States)

    Breguet, V; Boucher, J; Pesquet, F; Vojinovic, V; von Stockar, U; Marison, I W

    2008-03-01

    Due to residual oil retained within it, rapeseed press-cake has been shown to be effective for the removal of atrazine from water through an absorption mechanism. However, it is difficult to put this into practice due to the hygroscopic nature of the press-cake resulting in considerable swelling, together with the formation of a thick paste which hinders phase separation. In order to overcome this, press-cake has been immobilized in an alginate matrix. The kinetics and sorption efficiency of this immobilized press-cake to absorb the model pesticide atrazine, has been studied. The results show that the rate of atrazine removal is slower than for free press-cake, although the total amount of atrazine removed is the same (K(pc/w)=0.25). Phase separation was greatly simplified. The alginate immobilized press-cake could be dried, in order to reduce volume and weight, with no adverse effect on atrazine removal kinetics or sorption properties. PMID:18022667

  3. Effect of gamma irradiated sodium alginate on red amaranth (Amaranthus cruentus L.) as growth promoter

    Energy Technology Data Exchange (ETDEWEB)

    Mollah, M.Z.I. [Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, GPO Box 3787, Dhaka 1000 (Bangladesh); Khan, Mubarak A. [Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, GPO Box 3787, Dhaka 1000 (Bangladesh)], E-mail: makhan.inst@gmail.com; Khan, Ruhul A. [Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, GPO Box 3787, Dhaka 1000 (Bangladesh)

    2009-01-15

    In order to study the growth promotion behavior of sodium alginate (SA) on vegetable (red amaranth, Amaranthus cruentus L.), 3% aqueous solution of SA was irradiated by {gamma}-radiation (Co-60) of various total doses (12.5-50.0 kGy) at a dose rate of 3.5 kGy/h. Viscosity of the irradiated SA was found to decrease with increase in the radiation dose. The average molecular weight was also decreased from 10{sup 4} to 10{sup 3} orders. Red amaranth was cultivated in 18 different individual plots and SA solution (150 ppm) was applied on red amaranth after 10 days of seedlings at every 6 days interval. The morphological characters of vegetables were studied randomly in different unit plots. The irradiated SA of 37.5 kGy at 150 ppm solution showed the best performance. Dry matter of red amaranth significantly increased at 37.5 kGy of irradiated alginate treatment which was about 50% higher than that of the untreated samples. The effect of SA on red amaranth was found significant increase; i.e. plant height (17.8%), root length (12.7%), number of leaf (5.4%) and maximum leaf area (2%) compared to that of the control vegetative plant production.

  4. Effect of gamma irradiated sodium alginate on red amaranth (Amaranthus cruentus L.) as growth promoter

    International Nuclear Information System (INIS)

    In order to study the growth promotion behavior of sodium alginate (SA) on vegetable (red amaranth, Amaranthus cruentus L.), 3% aqueous solution of SA was irradiated by γ-radiation (Co-60) of various total doses (12.5-50.0 kGy) at a dose rate of 3.5 kGy/h. Viscosity of the irradiated SA was found to decrease with increase in the radiation dose. The average molecular weight was also decreased from 104 to 103 orders. Red amaranth was cultivated in 18 different individual plots and SA solution (150 ppm) was applied on red amaranth after 10 days of seedlings at every 6 days interval. The morphological characters of vegetables were studied randomly in different unit plots. The irradiated SA of 37.5 kGy at 150 ppm solution showed the best performance. Dry matter of red amaranth significantly increased at 37.5 kGy of irradiated alginate treatment which was about 50% higher than that of the untreated samples. The effect of SA on red amaranth was found significant increase; i.e. plant height (17.8%), root length (12.7%), number of leaf (5.4%) and maximum leaf area (2%) compared to that of the control vegetative plant production

  5. Effect of gamma irradiated sodium alginate on red amaranth ( Amaranthus cruentus L.) as growth promoter

    Science.gov (United States)

    Mollah, M. Z. I.; Khan, Mubarak A.; Khan, Ruhul A.

    2009-01-01

    In order to study the growth promotion behavior of sodium alginate (SA) on vegetable (red amaranth, Amaranthus cruentus L.), 3% aqueous solution of SA was irradiated by γ-radiation (Co-60) of various total doses (12.5-50.0 kGy) at a dose rate of 3.5 kGy/h. Viscosity of the irradiated SA was found to decrease with increase in the radiation dose. The average molecular weight was also decreased from 10 4 to 10 3 orders. Red amaranth was cultivated in 18 different individual plots and SA solution (150 ppm) was applied on red amaranth after 10 days of seedlings at every 6 days interval. The morphological characters of vegetables were studied randomly in different unit plots. The irradiated SA of 37.5 kGy at 150 ppm solution showed the best performance. Dry matter of red amaranth significantly increased at 37.5 kGy of irradiated alginate treatment which was about 50% higher than that of the untreated samples. The effect of SA on red amaranth was found significant increase; i.e. plant height (17.8%), root length (12.7%), number of leaf (5.4%) and maximum leaf area (2%) compared to that of the control vegetative plant production.

  6. Formulation and drying of alginate beads for controlled release and stabilization of invertase.

    Science.gov (United States)

    Santagapita, Patricio R; Mazzobre, M Florencia; Buera, M Pilar

    2011-09-12

    Several alternatives to the conventional alginate beads formulation were studied for encapsulation of invertase. Pectin was added to the alginate/enzyme solution while trehalose and β-cyclodextrin were added to the calcium gelation media. The effect of composition changes, freezing, drying methods (freeze, vacuum, or air drying), and thermal treatment were evaluated on invertase stability and its release kinetics from beads. The enzyme release mechanism from wet beads depended on pH. The addition of trehalose, pectin, and β-cyclodextrin modified the bead structure, leading in some cases to a release mechanism that included the relaxation of the polymer chains, besides Fickian diffusion. Enzyme release from vacuum-dried beads was much faster than from freeze-dried beads, probably due to their higher pore size. The inclusion of β-cyclodextrin and especially of pectin prevented enzyme activity losses during bead generation, and trehalose addition was fundamental for achieving adequate invertase protection during freezing, drying, and thermal treatment. Present results showed that several alternatives such as drying method, composition, as well as pH of the relese medium can be managed to control enzyme release. PMID:21809830

  7. Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013 (China); Luo, Honglin [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan 063009 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts.

  8. Hydrogels of sodium alginate in cationic surfactants: Surfactant dependent modulation of encapsulation/release toward Ibuprofen.

    Science.gov (United States)

    Jabeen, Suraya; Chat, Oyais Ahmad; Maswal, Masrat; Ashraf, Uzma; Rather, Ghulam Mohammad; Dar, Aijaz Ahmad

    2015-11-20

    The interaction of cetyltrimethylammoium bromide (CTAB) and its gemini homologue (butanediyl-1,4-bis (dimethylcetylammonium bromide), 16-4-16 with biocompatible polymer sodium alginate (SA) has been investigated in aqueous medium. Addition of K2CO3 influences viscoelastic properties of surfactant impregnated SA via competition between electrostatic and hydrophobic interactions. Viscosity of these polymer-surfactant systems increases with increase in concentration of K2CO3, and a cryogel is formed at about 0.5M K2CO3 concentration. The thermal stability of gel (5% SA+0.5M K2CO3) decreases with increase in surfactant concentration, a minimum is observed with increase in 16-4-16 concentration. The impact of surfactant addition on the alginate structure vis-à-vis its drug loading capability and release thereof was studied using Ibuprofen (IBU) as the model drug. The hydrogel with 16-4-16 exhibits higher IBU encapsulation and faster release in comparison to the one containing CTAB. This higher encapsulation-cum-faster release capability has been related to micelle mediated solubilization and greater porosity of the hydrogel with gemini surfactant. PMID:26344266

  9. Effect of Experimental Parameters on Alginate/Chitosan Microparticles for BCG Encapsulation.

    Science.gov (United States)

    Caetano, Liliana A; Almeida, António J; Gonçalves, Lídia M D

    2016-01-01

    The aim of the present study was to develop novel Mycobacterium bovis bacille Calmette-Guérin (BCG)-loaded polymeric microparticles with optimized particle surface characteristics and biocompatibility, so that whole live attenuated bacteria could be further used for pre-exposure vaccination against Mycobacterium tuberculosis by the intranasal route. BCG was encapsulated in chitosan and alginate microparticles through three different polyionic complexation methods by high speed stirring. For comparison purposes, similar formulations were prepared with high shear homogenization and sonication. Additional optimization studies were conducted with polymers of different quality specifications in a wide range of pH values, and with three different cryoprotectors. Particle morphology, size distribution, encapsulation efficiency, surface charge, physicochemical properties and biocompatibility were assessed. Particles exhibited a micrometer size and a spherical morphology. Chitosan addition to BCG shifted the bacilli surface charge from negative zeta potential values to strongly positive ones. Chitosan of low molecular weight produced particle suspensions of lower size distribution and higher stability, allowing efficient BCG encapsulation and biocompatibility. Particle formulation consistency was improved when the availability of functional groups from alginate and chitosan was close to stoichiometric proportion. Thus, the herein described microparticulate system constitutes a promising strategy to deliver BCG vaccine by the intranasal route. PMID:27187418

  10. Preparation and characterization of gatifloxacin-loaded alginate/poly (vinyl alcohol) electrospun nanofibers.

    Science.gov (United States)

    Arthanari, Saravanakumar; Mani, Ganesh; Jang, Jun Ho; Choi, Je O; Cho, Yun Ho; Lee, Jung Ho; Cha, Seung Eun; Oh, Han Seok; Kwon, Deok Han; Jang, Hyun Tae

    2016-05-01

    The aim of this study was to develop novel biomedicated electrospun nanofibers for controlled release. Pre-formulation studies were carried out for nanofibers of sodium alginate (SA) (2 wt %)/polyvinyl alcohol (PVA) (10 wt %) composites (2/8, 3/7 and 4/6), by an electrospinning technique. The morphology and average diameter of the nanofibers were investigated by scanning electron microscopy (SEM). The optimum ratio (3/7) was used to load gatifloxacin hydrochloride (GH) (1wt %), found to form smooth fibers with uniform structures. The drug entrapment in the composite nanofibers was confirmed by SEM, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and swelling behavior. The drug release behavior was investigated using phosphate-buffered saline (PBS) (pH 7.4) at 37°C for 24 h. The XRD and FTIR data demonstrate that there are good interactions between PVA and SA, possibly caused by hydrogen bonds. As much as 90% of the GH was released from the electrospun fibers within 6 h of incubation. Beyond this, the release was sustained for 24 h. The thickness of nanofibers greatly influenced the initial release and rate of drug release. Moreover, GH-loaded sodium alginate/PVA composite nanofibers exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound-healing applications. PMID:25510448

  11. Peptide-incorporated 3D porous alginate scaffolds with enhanced osteogenesis for bone tissue engineering.

    Science.gov (United States)

    Luo, Zuyuan; Yang, Yue; Deng, Yi; Sun, Yuhua; Yang, Hongtao; Wei, Shicheng

    2016-07-01

    Good bioactivity and osteogenesis of three-dimensional porous alginate scaffolds (PAS) are critical for bone tissue engineering. In this work, alginate and bone-forming peptide-1 (BFP-1), derived from bone morphogenetic protein-7 (BMP-7), have been combined together (without carbodiimide chemistry treatment) to develop peptide-incorporated PAS (p-PAS) for promoting bone repairing ability. The mechanical properties and SEM images show no difference between pure PAS and p-PAS. The release kinetics of the labeled peptide with 6-carboxy tetramethyl rhodamine from the PAS matrix suggests that the peptide is released in a relatively sustained manner. In the cell experiment, p-PAS show higher cell adhesion, spreading, proliferation and alkaline phosphatase (ALP) activity than the pristine PAS group, indicating that the BFP-1 released from p-PAS could significantly promote the aggregation and differentiation of osteoblasts, especially at 10μg/mL of trapped peptide concentration (p-PAS-10). Furthermore, p-PAS-10 was implanted into Beagle calvarial defects and bone regeneration was analyzed after 4 weeks. New bone formation was assessed by calcein and Masson's trichrome staining. The data reveal that p-PAS group exhibits significantly enhanced oseto-regenerative capability in vivo. The peptide-modified PAS with promoted bioactivity and osteogenic differentiation in vitro as well as bone formation ability in vivo could be promising tissue engineering materials for repairing and regeneration of bone defects. PMID:27022863

  12. Polyionic hybrid nano-engineered systems comprising alginate and chitosan for antihypertensive therapeutics.

    Science.gov (United States)

    Niaz, Taskeen; Nasir, Habib; Shabbir, Saima; Rehman, Asma; Imran, Muhammad

    2016-10-01

    Hydrophobic nature of virtually all antihypertensive (AHT) drugs is the major hindrance towards their oral administration. Current study focuses on the development of polyionic hybrid nano drug delivery systems comprising sodium alginate and chitosan, loaded with distinct AHT drugs (captopril, amlodipine and valsartan). Encapsulation efficiency of hybrid NCS increased in the order of amlodipine>valsartan>captopril with average value of 42±0.9%, 91±1.5% and 96±1.9%, respectively. Scanning electron microscopy revealed hybrid NCS with smooth topography and round appearance in case of captopril. FTIR analysis confirmed the cross-linking between amino and carboxylate group of chitosan and alginate to form polyionic structures at nano-scale. Zeta-sizer experiments revealed that particle size distribution had increased from 197±12nm to 341±15nm for void and captopril loaded NCS. However, highly positive zeta potential of +32±1.6mV was not decreased significantly. In vitro sustained release assays reflected excellent retention of AHT drug in hybrid nanoparticles at 4°C and 37°C in physiological buffer, as less than 8% of the total drug was released in first 24h. Thus, carbohydrate-based hybrid NCS offering high loading capacity, stability and sustained release of hydrophobic drugs can be excellent alternative to current AHT therapeutics. PMID:27212217

  13. Batch-wise adsorption, saxs and microscopic studies of zeolite pelletized with biopolymeric alginate

    Directory of Open Access Journals (Sweden)

    E. Chmielewská

    2011-03-01

    Full Text Available Removal of nitrates, sulfate and Zn(II ions from aqueous solutions through adsorption onto biopolymeric alginate/clinoptilolite-rich tuff pellets was studied by using an equilibrium batch technique. The idea of this approach of biosorbent fabrication is to promote the native zeolite adsorption performance and thus to prepare more efficient amphoteric tailor-made products for specific environmental targets. A flexible component, i.e., alginate biopolymer, and a rigid component (pulverized zeolite were crosslinked using Fe(III and Ca(II chlorides, additively. The extent of adsorption was found to be considerably higher than with the other mostly natural adsorbents examined towards similar pollutants. The equilibrium adsorption data for the above pollutants were satisfactorily fitted to Freundlich and Langmuir isotherms, respectively. According to the linscale SAXS pattern, there was a strong background visible, which may indicate the presence of a considerable amount of biopolymeric phase in the composite samples analysed. Scanning Tunneling, Electron and Atomic Force Microscopies helped visualize their surface texture and morphology.

  14. Rapid 3D Printing of Multifunctional Calcium Alginate Gel Pipes using Coaxial Jet Extruder

    Science.gov (United States)

    Rykaczewski, Konrad; Damle, Viraj

    2014-11-01

    Calcium alginate (CA) forms when solution containing sodium alginate (SA) comes in contact with a CaCl2 solution. The resulting gel is biocompatible as well as edible and is used in production of bio-scaffolds, artificial plant seeds, and edible substances. In the latter application, referred to in the culinary world as ``spherification,'' flavored liquids are mixed with the SA and dripped into CaCl2 solution to form gel encapsulated flavored ``marbles.'' Previously, crude 3D printing of CA structures has been achieved by stacking of such flavored liquid filled marbles. In turn, solid CA rods have been fabricated by properly mixing flow of the two solutions using a microfluidic device. Here we show that by using two circular cross-section coaxial nozzles to produce coaxial jets of the SA and CaCl2 solutions, liquid filled CA micro-to-mili scale gel pipes can be produced at speeds around ~ 150 mm/s. Such extrusion rate is compatible with most commercially available 3D printers, facilitating adoption of the CA pipe coaxial jet extruder. Here, the impact of inner and outer liquid properties and flow speeds on the gel pipe extrusion process is discussed. KR acknowledges startup funding from ASU.

  15. Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

    International Nuclear Information System (INIS)

    Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts

  16. Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism.

    Science.gov (United States)

    Higham, Alina K; Bonino, Christopher A; Raghavan, Srinivasa R; Khan, Saad A

    2014-07-21

    We examine the gelation of alginate undergoing ionic crosslinking upon ultraviolet (UV) irradiation using in situ dynamic rheology. Hydrogels are formed by combining alginate with calcium carbonate (CaCO3) particles and a photoacid generator (PAG). The PAG is photolyzed upon UV irradiation, resulting in the release of free calcium ions for ionic crosslinking. The viscous and elastic moduli during gelation are monitored as a function of the UV irradiation intensity, exposure time, alginate concentration, and the ratio between alginate and calcium carbonate. Gel time decreases as irradiation intensity increases because a larger concentration of PAG is photolyzed. Interestingly, dark curing, the continuing growth of microstructure in the absence of UV light, is observed. In some instances, the sample transitions from a solution to a gel during the dark curing phase. Additionally, when exposed to constant UV irradiation after the dark curing phase, samples reach the same plateau modulus as samples exposed to constant UV without dark curing, implying that dark curing does not affect the gelation mechanism. We believe the presence of dark curing is the result of the acidic environment persisting within the sample, allowing CaCO3 to dissociate, thereby releasing free Ca(2+) ions capable of binding with the available appropriate ionic blocks of the polymer chains. The growth of microstructure is then detected if the activation barrier has been crossed to release sufficient calcium ions. In this regard, we calculate a value of 30 J that represents the activation energy required to initiate gelation. PMID:24894636

  17. Study on the biological effect of radiation-degraded alginate and chitosan on plant in tissue culture

    International Nuclear Information System (INIS)

    The solution of chitosan (10%) and alginate (4%) were irradiated at doses of 10-250 kGy for degradation and the products were used for testing of plant growth promotion effect. The chitosan and alginate irradiated at 100 kGy and 75 kGy, respectively showed the strongest growth-promotion effect for plants namely L. latifolium, E. grandiflorum and C. morifolium in tissue culture. For shoot multiplication, the suitable concentrations are found to be ca. 50-200 mg/l for C. morifolium, 70-100 mg/l for L. latifolium and 30-100 mg/l E. grandiflorum with irradiated chitosan, while with irradiated alginate, it was 30-200 mg/l, 30-50 mg/l and 10-200 mg/l, respectively. The optimum concentrations for C. morifolium, E. grandiflorum, L. latifolium incubated on rooting medium are ca. 100 mg/l, 30 mg/l and 40 mg/l, respectively for irradiated chitosan and 100 mg/l for irradiated alginate. After acclimatizing for 30 days in the greenhouse, the survival ratio of the transferred C. morifolium, E. grandiflorum, L. latifolium plantlets treated with irradiated chitosan was improved 18%, 39% and 13%, respectively. (author)

  18. Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jing [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Yang Lihua [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Chan, Sidney M.N. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Luan Tiangang, E-mail: cesltg@mail.sysu.edu.cn [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Li Yan [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Tam, Nora F.Y., E-mail: bhntam@cityu.edu.hk [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong)

    2011-01-30

    The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

  19. Noninvasive evaluation of the vascular response to transplantation of alginate encapsulated islets using the dorsal skin-fold model.

    Science.gov (United States)

    Krishnan, Rahul; Arora, Rajan P; Alexander, Michael; White, Sean M; Lamb, Morgan W; Foster, Clarence E; Choi, Bernard; Lakey, Jonathan R T

    2014-01-01

    Alginate encapsulation reduces the risk of transplant rejection by evading immune-mediated cell injury and rejection; however, poor vascular perfusion results in graft failure. Since existing imaging models are incapable of quantifying the vascular response to biomaterial implants after transplantation, in this study, we demonstrate the use of in vivo laser speckle imaging (LSI) and wide-field functional imaging (WiFI) to monitor the microvascular environment surrounding biomaterial implants. The vascular response to two islet-containing biomaterial encapsulation devices, alginate microcapsules and a high-guluronate alginate sheet, was studied and compared after implantation into the mouse dorsal window chamber (N = 4 per implant group). Images obtained over a 14-day period using LSI and WiFI were analyzed using algorithms to quantify blood flow, hemoglobin oxygen saturation and vascular density. Using our method, we were able to monitor the changes in the peri-implant microvasculature noninvasively without the use of fluorescent dyes. Significant changes in blood flow, hemoglobin oxygen saturation and vascular density were noted as early as the first week post-transplant. The dorsal window chamber model enables comparison of host responses to transplanted biomaterials. Future experiments will study the effect of changes in alginate composition on the vascular and immune responses. PMID:24176195

  20. Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

    International Nuclear Information System (INIS)

    The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

  1. Development of an angiogenesis-promoting microvesicle-alginate-polycaprolactone composite graft for bone tissue engineering applications

    Science.gov (United States)

    Zhang, Liming; Lei, Qian; Zhao, Aiqi; Wang, Hongxiang; Li, Qiubai

    2016-01-01

    One of the major challenges of bone tissue engineering applications is to construct a fully vascularized implant that can adapt to hypoxic environments in vivo. The incorporation of proangiogenic factors into scaffolds is a widely accepted method of achieving this goal. Recently, the proangiogenic potential of mesenchymal stem cell-derived microvesicles (MSC-MVs) has been confirmed in several studies. In the present study, we incorporated MSC-MVs into alginate-polycaprolactone (PCL) constructs that had previously been developed for bone tissue engineering applications, with the aim of promoting angiogenesis and bone regeneration. MSC-MVs were first isolated from the supernatant of rat bone marrow-derived MSCs and characterized by scanning electron microscopic, confocal microscopic, and flow cytometric analyses. The proangiogenic potential of MSC-MVs was demonstrated by the stimulation of tube formation of human umbilical vein endothelial cells in vitro. MSC-MVs and osteodifferentiated MSCs were then encapsulated with alginate and seeded onto porous three-dimensional printed PCL scaffolds. When combined with osteodifferentiated MSCs, the MV-alginate-PCL constructs enhanced vessel formation and tissue-engineered bone regeneration in a nude mouse subcutaneous bone formation model, as demonstrated by micro-computed tomographic, histological, and immunohistochemical analyses. This MV-alginate-PCL construct may offer a novel, proangiogenic, and cost-effective option for bone tissue engineering. PMID:27231660

  2. Development of an angiogenesis-promoting microvesicle-alginate-polycaprolactone composite graft for bone tissue engineering applications.

    Science.gov (United States)

    Xie, Hui; Wang, Zhenxing; Zhang, Liming; Lei, Qian; Zhao, Aiqi; Wang, Hongxiang; Li, Qiubai; Chen, Zhichao; Zhang, WenJie

    2016-01-01

    One of the major challenges of bone tissue engineering applications is to construct a fully vascularized implant that can adapt to hypoxic environments in vivo. The incorporation of proangiogenic factors into scaffolds is a widely accepted method of achieving this goal. Recently, the proangiogenic potential of mesenchymal stem cell-derived microvesicles (MSC-MVs) has been confirmed in several studies. In the present study, we incorporated MSC-MVs into alginate-polycaprolactone (PCL) constructs that had previously been developed for bone tissue engineering applications, with the aim of promoting angiogenesis and bone regeneration. MSC-MVs were first isolated from the supernatant of rat bone marrow-derived MSCs and characterized by scanning electron microscopic, confocal microscopic, and flow cytometric analyses. The proangiogenic potential of MSC-MVs was demonstrated by the stimulation of tube formation of human umbilical vein endothelial cells in vitro. MSC-MVs and osteodifferentiated MSCs were then encapsulated with alginate and seeded onto porous three-dimensional printed PCL scaffolds. When combined with osteodifferentiated MSCs, the MV-alginate-PCL constructs enhanced vessel formation and tissue-engineered bone regeneration in a nude mouse subcutaneous bone formation model, as demonstrated by micro-computed tomographic, histological, and immunohistochemical analyses. This MV-alginate-PCL construct may offer a novel, proangiogenic, and cost-effective option for bone tissue engineering. PMID:27231660

  3. Fabrication and evaluation of biomimetic scaffolds by using collagen-alginate fibrillar gels for potential tissue engineering applications

    International Nuclear Information System (INIS)

    Pore architecture and its stable functionality under cell culturing of three dimensional (3D) scaffolds are of great importance for tissue engineering purposes. In this study, alginate was incorporated with collagen to fabricate collagen-alginate composite scaffolds with different collagen/alginate ratios by lyophilizing the respective composite gels formed via collagen fibrillogenesis in vitro and then chemically crosslinking. The effects of alginate amount and crosslinking treatment on pore architecture, swelling behavior, enzymatic degradation and tensile property of composite scaffolds were systematically investigated. The relevant results indicated that the present strategy was simple but efficient to fabricate highly interconnected strong biomimetic 3D scaffolds with nanofibrous surface. NIH3T3 cells were used as a model cell to evaluate the cytocompatibility, attachment to the nanofibrous surface and porous architectural stability in terms of cell proliferation and infiltration within the crosslinked scaffolds. Compared with the mechanically weakest crosslinked collagen sponges, the cell-cultured composite scaffolds presented a good porous architecture, thus permitting cell proliferation on the top surface as well as infiltration into the inner part of 3D composite scaffolds. These composite scaffolds with pore size ranging from 150 to 300 μm, over 90% porosity, tuned biodegradability and water-uptake capability are promising for tissue engineering applications.

  4. Effect of free calcium concentration and ionic strength on alginate fouling in cross-flow membrane filtration

    NARCIS (Netherlands)

    Brink, van den P.; Zwijnenburg, A.; Smith, G.; Temmink, B.G.; Loosdrecht, van M.C.

    2009-01-01

    Extracellular polymeric substances (EPS) are generally negatively charged polymers. Membrane fouling in membrane bioreactors (MBRs) by EPS is therefore influenced by the water chemistry of the mixed liquor (calcium concentration, foulant concentration and ionic strength). We used alginate as a model

  5. Repulsion of Meloidogyne incognita by Alginate Pellets Containing Hyphae of Monacrosporium cionopagum, M. ellipsosporum, or Hirsutella rhossiliensis

    OpenAIRE

    Robinson, A. F.; Jaffee, B. A.

    1996-01-01

    The responses of second-stage juveniles (J2) of Meloidogyne incognita race 3 to calcium alginate pellets containing hyphae of the nematophagous fungi Monacrosporiura cionopagum, M. ellipsosporum, and Hirsutella rhossiliensis were examined using cylinders (38-mm-diam., 40 or 72 mm long) of sand (94%

  6. Feasibility studies on the separation of radiostrontium from contaminated groundwater using a column of calcium alginate beads

    International Nuclear Information System (INIS)

    The utility of calcium alginate beads for sorption of radiostrontium in fixed-bed column has been examined. An extended laboratory scale column run has been conducted using simulated contaminated groundwater as the feed solution. The loaded activity has been eluted using dilute nitric acid. (author)

  7. Alginate hydrogel enriched with enamel matrix derivative to target osteogenic cell differentiation in TiO2 scaffolds

    DEFF Research Database (Denmark)

    Pullisaar, Helen; Verket, Anders; Szoke, Krisztina; Tiainen, Hanna; Haugen, Håvard J; Brinchmann, Jan E; Reseland, Janne E; Østrup, Esben

    2015-01-01

    various donors on titanium dioxide (TiO2) scaffolds coated with an alginate hydrogel enriched with enamel matrix derivative. Cells were harvested for quantitative reverse transcription polymerase chain reaction on days 14 and 21, and medium was collected on days 2, 14, and 21 for protein analyses. Neither...

  8. Fibronectin-Alginate microcapsules improve cell viability and protein secretion of encapsulated Factor IX-engineered human mesenchymal stromal cells.

    Science.gov (United States)

    Sayyar, Bahareh; Dodd, Megan; Marquez-Curtis, Leah; Janowska-Wieczorek, Anna; Hortelano, Gonzalo

    2015-01-01

    Continuous delivery of proteins by engineered cells encapsu-lated in biocompatible polymeric microcapsules is of considerable therapeutic potential. However, this technology has not lived up to expectations due to inadequate cell--matrix interactions and subsequent cell death. In this study we hypoth-esize that the presence of fibronectin in an alginate matrix may enhance the viability and functionality of encapsulated human cord blood-derived mesenchymal stromal cells (MSCs) expressing the human Factor IX (FIX) gene. MSCs were encapsulated in alginate-PLL microcapsules containing 10, 100, or 500 μg/ml fibronectin to ameliorate cell survival. MSCs in microcapsules with 100 and 500 μg/ml fibronectin demonstrated improved cell viability and proliferation and higher FIX secretion compared to MSCs in non-supplemented microcapsules. In contrast, 10 μg/ml fibronectin did not significantly affect the viability and protein secretion from the encapsulated cells. Differentiation studies demonstrated osteogenic (but not chondrogenic or adipogenic) differentiation capability and efficient FIX secretion of the enclosed MSCs in the fibronectin-alginate suspension culture. Thus, the use of recombinant MSCs encapsulated in fibronectin-alginate microcapsules in basal or osteogenic cultures may be of practical use in the treatment of hemophilia B. PMID:24564349

  9. Fabrication and evaluation of biomimetic scaffolds by using collagen-alginate fibrillar gels for potential tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Sang Lin; Luo Dongmei; Xu Songmei; Wang Xiaoliang; Li Xudong, E-mail: xli20004@yahoo.com

    2011-03-12

    Pore architecture and its stable functionality under cell culturing of three dimensional (3D) scaffolds are of great importance for tissue engineering purposes. In this study, alginate was incorporated with collagen to fabricate collagen-alginate composite scaffolds with different collagen/alginate ratios by lyophilizing the respective composite gels formed via collagen fibrillogenesis in vitro and then chemically crosslinking. The effects of alginate amount and crosslinking treatment on pore architecture, swelling behavior, enzymatic degradation and tensile property of composite scaffolds were systematically investigated. The relevant results indicated that the present strategy was simple but efficient to fabricate highly interconnected strong biomimetic 3D scaffolds with nanofibrous surface. NIH3T3 cells were used as a model cell to evaluate the cytocompatibility, attachment to the nanofibrous surface and porous architectural stability in terms of cell proliferation and infiltration within the crosslinked scaffolds. Compared with the mechanically weakest crosslinked collagen sponges, the cell-cultured composite scaffolds presented a good porous architecture, thus permitting cell proliferation on the top surface as well as infiltration into the inner part of 3D composite scaffolds. These composite scaffolds with pore size ranging from 150 to 300 {mu}m, over 90% porosity, tuned biodegradability and water-uptake capability are promising for tissue engineering applications.

  10. Biochemical Monitoring of Spinal Cord Injury by FT-IR Spectroscopy--Effects of Therapeutic Alginate Implant in Rat Models.

    Directory of Open Access Journals (Sweden)

    Sandra Tamosaityte

    Full Text Available Spinal cord injury (SCI induces complex biochemical changes, which result in inhibition of nervous tissue regeneration abilities. In this study, Fourier-transform infrared (FT-IR spectroscopy was applied to assess the outcomes of implants made of a novel type of non-functionalized soft calcium alginate hydrogel in a rat model of spinal cord hemisection (n = 28. Using FT-IR spectroscopic imaging, we evaluated the stability of the implants and the effects on morphology and biochemistry of the injured tissue one and six months after injury. A semi-quantitative evaluation of the distribution of lipids and collagen showed that alginate significantly reduced injury-induced demyelination of the contralateral white matter and fibrotic scarring in the chronic state after SCI. The spectral information enabled to detect and localize the alginate hydrogel at the lesion site and proved its long-term persistence in vivo. These findings demonstrate a positive impact of alginate hydrogel on recovery after SCI and prove FT-IR spectroscopic imaging as alternative method to evaluate and optimize future SCI repair strategies.

  11. Biochemical Monitoring of Spinal Cord Injury by FT-IR Spectroscopy—Effects of Therapeutic Alginate Implant in Rat Models

    Science.gov (United States)

    Uckermann, Ortrud; Sitoci-Ficici, Kerim H.; Later, Robert; Beiermeister, Rudolf; Doberenz, Falko; Gelinsky, Michael; Leipnitz, Elke; Schackert, Gabriele; Koch, Edmund; Sablinskas, Valdas; Steiner, Gerald; Kirsch, Matthias

    2015-01-01

    Spinal cord injury (SCI) induces complex biochemical changes, which result in inhibition of nervous tissue regeneration abilities. In this study, Fourier-transform infrared (FT-IR) spectroscopy was applied to assess the outcomes of implants made of a novel type of non-functionalized soft calcium alginate hydrogel in a rat model of spinal cord hemisection (n = 28). Using FT-IR spectroscopic imaging, we evaluated the stability of the implants and the effects on morphology and biochemistry of the injured tissue one and six months after injury. A semi-quantitative evaluation of the distribution of lipids and collagen showed that alginate significantly reduced injury-induced demyelination of the contralateral white matter and fibrotic scarring in the chronic state after SCI. The spectral information enabled to detect and localize the alginate hydrogel at the lesion site and proved its long-term persistence in vivo. These findings demonstrate a positive impact of alginate hydrogel on recovery after SCI and prove FT-IR spectroscopic imaging as alternative method to evaluate and optimize future SCI repair strategies. PMID:26559822

  12. In Situ Transplantation of Alginate Bioencapsulated Adipose Tissues Derived Stem Cells (ADSCs via Hepatic Injection in a Mouse Model.

    Directory of Open Access Journals (Sweden)

    Mong-Jen Chen

    Full Text Available Adipose tissue derived stem cells (ADSCs transplantation has recently gained widespread enthusiasm, particularly in the perspective to use them as potential alternative cell sources for hepatocytes in cell based therapy, mainly because of their capability of hepatogenic differentiation in vitro and in vivo. But some challenges remain to be addressed, including whether ADSCs can be provided effectively to the target organ and whether subsequent proliferation of transplanted cells can be achieved. To date, intrasplenic injection is the conventional method to deliver ADSCs into the liver; however, a number of donor cells retained in the spleen has been reported. In this study, our objective is to evaluate a novel route to transplant ADSCs specifically to the liver. We aimed to test the feasibility of in situ transplantation of ADSCs by injecting bioencapsulated ADSCs into the liver in mouse model.The ADSCs isolated from human alpha 1 antitrypsin (M-hAAT transgenic mice were used to allow delivered ADSCs be readily identified in the liver of recipient mice, and alginate was selected as a cell carrier. We first evaluated whether alginate microspheres are implantable into the liver tissue by injection and whether ADSCs could migrate from alginate microspheres (study one. Once proven, we then examined the in vivo fate of ADSCs loaded microspheres in the liver. Specifically, we evaluated whether transplanted, undifferentiated ASDCs could be induced by the local microenvironment toward hepatogenic differentiation and the distribution of surviving ADSCs in major tissue organs (study two.Our results indicated ADSCs loaded alginate microspheres were implantable into the liver. Both degraded and residual alginate microspheres were observed in the liver up to three weeks. The viable ADSCs were detectable surrounding degraded and residual alginate microspheres in the liver and other major organs such as bone marrow and the lungs. Importantly, transplanted

  13. A study of extraction and characterization of alginates obtained from brown macroalgae Sargassum duplicatum and Sargassum crassifolium from Indonesia

    Directory of Open Access Journals (Sweden)

    Decky J. Indrani

    2013-06-01

    Full Text Available Background: Worldwide commercially available alginate have been used for tissue engineering purposes. The macroalgae Sargassum obtained from Indonesia have been used for various purposes, however, they have not been applied for tissue engineering scaffolds. Purpose: This study was aimed to extract alginate from the macroalgae Sargassum from Indonesia sea and to characterize in morphology, chemical element and functional groups. Methods: Macroalgae Sargassum duplicatum (S. Duplicatum and Sargassum crassifolium (S. Crassifolium were collected from Banten, Indonesia. Extraction of alginates were carried out using the alkaline extraction procedure. Scanning electron microscopy as well as X-ray Fluorescence and Fouirer Transform Infra-Red spectroscopy were used to characterize the extracted powders. Obtained data from the extracted powders were compared to those of the commercially available alginate. Results: Extraction using the alkaline method has resulted in S.duplicatum and S.crassifolium alginate powders. Alginate particles were suggested as irregular shapes with various dimension. Element components were mainly Na and Ca, whereas, minor elements were considered as negative impurities. COO- and C-O-C groups were evident in the finger print regio. The characteristics of Alginates extracted from the macroalgae S.duplicatum and S.crassifolium found similar to those of the commercially available alginate. Conclusion: Extraction obtained from the macroalgae S.duplicatum and S.crassifolium showed the typical alginate and the morphology, chemical element and functional groups were in agreement with those of the commercially available alginate.Latar belakang: Alginat dari berbagai penjuru dunia telah digunakan untuk kegunaan rekayasa jaringan. Alginat dari alga makro Sargassum yang diperoleh dari Indonesia telah digunakan untuk berbagai kegunaan, namun ini belum diterapkan untuk scaffold jaringan. Tujuan: Untuk mengekstrak alginat dari alga makro

  14. Alginate-whey protein dry powder optimized for target delivery of essential oils to the intestine of chickens.

    Science.gov (United States)

    Zhang, Y; Gong, J; Yu, H; Guo, Q; Defelice, C; Hernandez, M; Yin, Y; Wang, Q

    2014-10-01

    In poultry production, there is a lack of effective and convenient approaches to deliver bioactive compounds such as some essential oils, which have been proposed as alternatives to antibiotic growth promoters. The objective of this research was to develop a method for target delivery of essential oils in feed to the lower intestines of chickens. Carvacrol was used as a model essential oil, and 2 food-grade biopolymers, alginate and whey protein, were selected to encapsulate carvacrol in microparticles. The effects of a medium molecular weight alginate, a low molecular weight alginate (LBA), and whey protein concentrations on the properties of carvacrol-loaded microparticles were investigated using response surface methodology. The encapsulation efficiencies for all the tested formulations were ≥ 98% and carvacrol content in the dry microparticles was 72 ± 2% (wt/wt). The microparticles showed good gastric resistance and rapid intestinal release under simulated gastrointestinal conditions. Alginate concentrations had the strongest influence on the gastric resistance of microparticles, whereas whey protein was the dominant parameter in controlling the intestinal release. The concentration of LBA was found to be the critical factor affecting the mechanical strength of the microparticles. A predicted optimum formulation from in vitro optimization was tested in chickens. It was found that a negligible amount of carvacrol was detected in the intestines of chickens fed with unencapsulated carvacrol. Microparticles of predicted optimum formulation delivered a remarkably higher concentration of carvacrol to the jejunum and ileum regions. The high concentration was sustained for more than 3 h after oral administration. The in vivo release of carvacrol from the microparticles appeared faster than release from in vitro simulation. Nonetheless, the in vitro simulation provided good indications of the in vivo performance, and thus may serve as a useful tool for formula

  15. The antioxidant properties of oligo sodium alginates prepared by radiation-induced degradation in aqueous and hydrogen peroxide solutions

    International Nuclear Information System (INIS)

    In this study, the radiation-induced degradation of sodium alginates (NaAlg), having different guluronic acids (G) and mannuronic acid (M) ratios, (G/M), in aqueous and hydrogen peroxide solutions were investigated first; after that, the antioxidative properties of the oligo sodium alginates prepared were identified. Radiation degradation yield values, G(S), were determined for each irradiation condition and compared with those of the dry-state-irradiated NaAlg. The results showed that the oligo sodium alginates with M¯n from 1000 to 3750 Da could be easily prepared by γ-irradiation of NaAlg solution in the presence of small amount of hydrogen peroxide at low doses (below 5.0 kGy) and by controlling the G/M. The antioxidant properties of the fractions with various molecular weight and G/M were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH·), and 50% inhibition concentrations of LF120 NaAlg, which was irradiated in aqueous solution and H2O2 solution at a dose of 2.5 kGy and having number average molecular weights of 10.2 and 3.75 kDa were found to be 10.0 and 2.5 mg/ml, respectively. The results demonstrated that its molecular weight was an important factor in controlling the antioxidant properties of NaAlg, and due to the sharp decrease in molecular weight in the case of aqueous media irradiation the effect of G/M of initial polymer became unimportant whereas the dry-state-irradiated NaAlgs behaved conversely. - Highlights: ► The radiation-induced degradation of sodium alginates having different guluronic acids and mannuronic acid ratios. ► Degradation of NaAlg in aqueous solution in the presence or absence of hydrogen peroxide. ► Antioxidant properties of oligo sodium alginates.

  16. Modeling and Re-Engineering of Azotobacter vinelandii Alginate Lyase to Enhance Its Catalytic Efficiency for Accelerating Biofilm Degradation

    Science.gov (United States)

    Jang, Chul Ho; Piao, Yu Lan; Huang, Xiaoqin; Yoon, Eun Jeong; Park, So Hee; Lee, Kyoung; Zhan, Chang-Guo; Cho, Hoon

    2016-01-01

    Alginate is known to prevent elimination of Pseudomonas aeruginosa biofilms. Alginate lyase (AlgL) might therefore facilitate treatment of Pseudomonas aeruginosa-infected cystic fibrosis patients. However, the catalytic activity of wild-type AlgL is not sufficiently high. Therefore, molecular modeling and site-directed mutagenesis of AlgL might assist in enzyme engineering for therapeutic development. AlgL, isolated from Azotobacter vinelandii, catalyzes depolymerization of alginate via a β-elimination reaction. AlgL was modeled based on the crystal structure template of Sphingomonas AlgL species A1-III. Based on this computational analysis, AlgL was subjected to site-directed mutagenesis to improve its catalytic activity. The kcat/Km of the K194E mutant showed a nearly 5-fold increase against the acetylated alginate substrate, as compared to the wild-type. Double and triple mutants (K194E/K245D, K245D/K319A, K194E/K245D/E312D, and K194E/K245D/K319A) were also prepared. The most potent mutant was observed to be K194E/K245D/K319A, which has a 10-fold improved kcat value (against acetylated alginate) compared to the wild-type enzyme. The antibiofilm effect of both AlgL forms was identified in combination with piperacillin/tazobactam (PT) and the disruption effect was significantly higher in mutant AlgL combined with PT than wild-type AlgL. However, for both the wild-type and K194E/K245D/K319A mutant, the use of the AlgL enzyme alone did not show significant antibiofilm effect. PMID:27253324

  17. Effect of alginate on satiation, appetite, gastric function, and selected gut satiety hormones in overweight and obesity.

    Science.gov (United States)

    Odunsi, Suwebatu T; Vázquez-Roque, María I; Camilleri, Michael; Papathanasopoulos, Athanasios; Clark, Matthew M; Wodrich, Lynne; Lempke, Mary; McKinzie, Sanna; Ryks, Michael; Burton, Duane; Zinsmeister, Alan R

    2010-08-01

    Lack of control of food intake, excess size, and frequency of meals are critical to the development of obesity. The stomach signals satiation postprandially and may play an important role in control of calorie intake. Sodium alginate (based on brown seaweed Laminaria digitata) is currently marketed as a weight loss supplement, but its effects on gastric motor functions and satiation are unknown. We evaluated effects of 10 days treatment with alginate or placebo on gastric functions, satiation, appetite, and gut hormones associated with satiety in overweight or obese adults. We conducted a randomized, 1:1, placebo-controlled, allocation-concealed study in 48 overweight or obese participants with excluded psychiatric comorbidity and binge eating disorder. All underwent measurements of gastric emptying (GE), fasting, and postprandial gastric volumes (GVs), postprandial satiation, calorie intake at a free choice meal and selected gut hormones after 1 week of alginate (three capsules vs. matching placebo per day, ingested 30 min before the main meal). Six capsules were ingested with water 30 min before the GE, GV, and satiation tests on days 8-10. There were no treatment group effects on GE or volumes, gut hormones (ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY)), satiation, total and macronutrient calorie intake at a free choice meal. There was no difference detected in results between obese and overweight patients. Alginate treatment for a period of 10 days showed no effect on gastric motor functions, satiation, appetite, or gut hormones. These results question the use of short-term alginate treatment for weight loss. PMID:19960001

  18. Radiopaque alginate microcapsules for X-ray visualization and immunoprotection of cellular therapeutics.

    Science.gov (United States)

    Barnett, B P; Kraitchman, D L; Lauzon, C; Magee, C A; Walczak, P; Gilson, W D; Arepally, A; Bulte, J W M

    2006-01-01

    Alginate-poly-L-lysine-alginate (APA) microcapsules have been explored as vehicles for therapeutic drug and cell delivery. The permselectivity of these capsules provides a unique means of controlled drug release and immunoisolation of encapsulated cells. Immunoisolation is especially attractive as it abrogates the need for chronic immunosuppressive therapy and opens up the possibility for the delivery of numerous cell sources including xenogeneic grafts. APA microcapsules containing cellular therapeutics have proven effective in the short-term treatment of a wide range of diseases requiring enzyme or endocrine replacement therapy, including type I diabetes. If these microcapsules could be noninvasively monitored with X-ray imaging modalities (i.e., fluoroscopy, CT, and digital subtraction angiography), questions such as the ideal transplantation site, the best means of delivery, and the long-term survival of grafts could be better addressed. We have developed two novel alginate-based radiopaque microcapsule formulations containing either barium sulfate (Ba X-Caps) or bismuth sulfate (Bi X-Caps). As compared to conventional, nonradiopaque APA capsules, Ba X-Caps and Bi X-Caps containing human cadaveric islets resulted in a decrease in cellular viability of less than 5% up to 14 days after encapsulation. Both radiopaque capsules were found to be permeable to lectins or =120 kDa, thus ensuring the blockage of the penetration of antibodies while allowing free diffusion of insulin and nutrients. The glucose-responsive insulin secretion of the radiopaque encapsulated human islets was found to be unaltered compared to that of unlabeled controls, with human C-peptide levels ranging from 3.21 to 2.87 (Ba X-Caps) and 3.23 to 2.87 (Bi X-Caps) ng/islet at 7 and 14 days postencapsulation, respectively. Using fluoroscopy, both Ba X-Caps and Bi X-Caps could be readily visualized as single radiopaque entities in vitro. Furthermore, following transplantation in vivo in mice and

  19. Microencapsulated Aliivibrio fischeri in Alginate Microspheres for Monitoring Heavy Metal Toxicity in Environmental Waters

    Directory of Open Access Journals (Sweden)

    Dedi Futra

    2014-12-01

    Full Text Available In this article a luminescence fiber optic biosensor for the microdetection of heavy metal toxicity in waters based on the marine bacterium Aliivibrio fischeri (A. fischeri encapsulated in alginate microspheres is described. Cu(II, Cd(II, Pb(II, Zn(II, Cr(VI, Co(II, Ni(II, Ag(I and Fe(II were selected as sample toxic heavy metal ions for evaluation of the performance of this toxicity microbiosensor. The loss of bioluminescence response from immobilized A. fischeri bacterial cells corresponds to changes in the toxicity levels. The inhibition of the luminescent biosensor response collected at excitation and emission wavelengths of 287 ± 2 nm and 487 ± 2 nm, respectively, was found to be reproducible and repeatable within the relative standard deviation (RSD range of 2.4–5.7% (n = 8. The toxicity biosensor based on alginate micropsheres exhibited a lower limit of detection (LOD for Cu(II (6.40 μg/L, Cd(II (1.56 μg/L, Pb(II (47 μg/L, Ag(I (18 μg/L than Zn(II (320 μg/L, Cr(VI (1,000 μg/L, Co(II (1700 μg/L, Ni(II (2800 μg/L, and Fe(III (3100 μg/L. Such LOD values are lower when compared with other previous reported whole cell toxicity biosensors using agar gel, agarose gel and cellulose membrane biomatrices used for the immobilization of bacterial cells. The A. fischeri bacteria microencapsulated in alginate biopolymer could maintain their metabolic activity for a prolonged period of up to six weeks without any noticeable changes in the bioluminescence response. The bioluminescent biosensor could also be used for the determination of antagonistic toxicity levels for toxicant mixtures. A comparison of the results obtained by atomic absorption spectroscopy (AAS and using the proposed luminescent A. fischeri-based biosensor suggests that the optical toxicity biosensor can be used for quantitative microdetermination of heavy metal toxicity in environmental water samples.

  20. Effects of formulation variables on viability of L. casei loaded in whey protein-Ca alginate microparticles in simulated in vivo conditions

    OpenAIRE

    Smilkov, Katarina; Petrusevska Tozi, Lidija; Petreska Ivanovska, Tanja; Geskovski, Nikola; Petkovska, Rumenka; Glavas Dodov, Marija; Baceva, Katerina; Dimitrovski, Dejan; MLADENOVSKA, KRISTINA

    2011-01-01

    The objective of this work was to assess the influence of formulation variables of L. casei loaded whey protein-Ca-alginate microparticles on probiotic survival under different conditions, representing simulated in vivo environment.

  1. An analytic study on the effect of alginate on the velocity profiles of blood in rectangular microchannels using microparticle image velocimetry.

    Directory of Open Access Journals (Sweden)

    Katie L Pitts

    Full Text Available It is desired to understand the effect of alginic acid sodium salt from brown algae (alginate as a viscosity modifier on the behavior of blood in vitro using a micro-particle image velocimetry (µPIV system. The effect of alginate on the shape of the velocity profile, the flow rate and the maximum velocity achieved in rectangular microchannels channels are measured. The channels were constructed of polydimethylsiloxane (PDMS, a biocompatible silicone. Porcine blood cells suspended in saline was used as the working fluid at twenty percent hematocrit (H = 20. While alginate was only found to have minimal effect on the maximum velocity and the flow rate achieved, it was found to significantly affect the shear rate at the wall by between eight to a hundred percent.

  2. Formulation Optimization and Evaluation of Probiotic Lactobacillus sporogenes-Loaded Sodium Alginate with Carboxymethyl Cellulose Mucoadhesive Beads Using Design Expert Software

    OpenAIRE

    Solanki, Himanshu K.; Dushyant A. Shah

    2016-01-01

    The present study deals with the formulation optimization of sodium carboxymethyl cellulose-alginate mucoadhesive beads containing probiotic Lactobacillus sporogenes through ionotropic gelation using 32 factorial design. The effect of sodium carboxymethyl cellulose-alginate concentration on the probiotic entrapment efficiency (PEE, %), viability in simulated gastric fluid (log CFU/g), and mucoadhesion over 8 hr (%) was optimized. The optimized beads containing probiotic Lactobacillus sporogen...

  3. Alginate Production by Pseudomonas putida Creates a Hydrated Microenvironment and Contributes to Biofilm Architecture and Stress Tolerance under Water-Limiting Conditions▿

    OpenAIRE

    Chang, Woo-Suk; van de Mortel, Martijn; Nielsen, Lindsey; Nino de Guzman, Gabriela; Li, Xiaohong; Halverson, Larry J.

    2007-01-01

    Biofilms exist in a variety of habitats that are routinely or periodically not saturated with water, and residents must integrate cues on water abundance (matric stress) or osmolarity (solute stress) into lifestyle strategies. Here we examine this hypothesis by assessing the extent to which alginate production by Pseudomonas putida strain mt-2 and by other fluorescent pseudomonads occurs in response to water limitations and how the presence of alginate in turn influences biofilm development a...

  4. Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads

    Science.gov (United States)

    Dashtdar, Havva; Selvaratnam, Lakshmi; Balaji Raghavendran, Hanumantharao; Suhaeb, Abdulrazzaq Mahmod; Ahmad, Tunku Sara

    2016-01-01

    Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis. PMID:26966647

  5. Papain entrapment in alginate beads for stability improvement and site-specific delivery: Physicochemical characterization and factorial optimization using neural network modeling

    OpenAIRE

    Sankalia, Mayur G.; Mashru, Rajshree C.; Sankalia, Jolly M.; Sutariya, Vijay B.

    2005-01-01

    This work examines the influence of various process parameters (like sodium alginate concentration, calcium chloride concentration, and hardening time) on papain entrapped in ionotropically cross-linked alginate beads for stability improvement and site-specific delivery to the small intestine using neural network modeling. A 33 full-factorial design and feed-forward neural network with multilayer perceptron was used to investigate the effect of process variables on percentage of entrapment, t...

  6. Effect of alginate on the aggregation kinetics of copper oxide nanoparticles (CuO NPs): bridging interaction and hetero-aggregation induced by Ca(2.).

    Science.gov (United States)

    Miao, Lingzhan; Wang, Chao; Hou, Jun; Wang, Peifang; Ao, Yanhui; Li, Yi; Lv, Bowen; Yang, Yangyang; You, Guoxiang; Xu, Yi

    2016-06-01

    The stability of CuO nanoparticles (NPs) is expected to play a key role in the environmental risk assessment of nanotoxicity in aquatic systems. In this study, the effect of alginate (model polysaccharides) on the stability of CuO NPs in various environmentally relevant ionic strength conditions was investigated by using time-resolved dynamic light scattering. Significant aggregation of CuO NPs was observed in the presence of both monovalent and divalent cations. The critical coagulation concentrations (CCC) were 54.5 and 2.9 mM for NaNO3 and Ca(NO3)2, respectively. The presence of alginate slowed nano-CuO aggregation rates over the entire NaNO3 concentration range due to the combined electrostatic and steric effect. High concentrations of Ca(2+) (>6 mM) resulted in stronger adsorption of alginate onto CuO NPs; however, enhanced aggregation of CuO NPs occurred simultaneously under the same conditions. Spectroscopic analysis revealed that the bridging interaction of alginate with Ca(2+) might be an important mechanism for the enhanced aggregation. Furthermore, significant coagulation of the alginate molecules was observed in solutions of high Ca(2+) concentrations, indicating a hetero-aggregation mechanism between the alginate-covered CuO NPs and the unabsorbed alginate. These results suggested a different aggregation mechanism of NPs might co-exist in aqueous systems enriched with natural organic matter, which should be taken into consideration in future studies. Graphical abstract Hetero-aggregation mechanism of CuO nanoparticles and alginate under high concentration of Ca(2.) PMID:26931664

  7. Removal of Reactive Black 5 (RB5) Dye from Aquatic Solution by Using of Adsorption onto Synthesized SodiumAlginate Magnetic Beads

    OpenAIRE

    H. Vahedi; M Shirzad Siboni; F Pourfarzi; M.R Samarghandi; R Shokohi

    2011-01-01

    "nBackground and Objectives: Industrial wastewater included the dyes one of the important sources of environmental pollution, that founded in loom wastewater which are harmful for human health and environment. Therefore, the purpose of this research was investigated removal of RB5 dye from aquatic solution by using of adsorption onto synthesized magnetic sodium alginate beads."nMaterial and Methods: At first, synthesized magnetic sodium alginate beads. Then, acquired beads optimum dosage equa...

  8. Functionalized magnetic iron oxide/alginate core-shell nanoparticles for targeting hyperthermia.

    Science.gov (United States)

    Liao, Shih-Hsiang; Liu, Chia-Hung; Bastakoti, Bishnu Prasad; Suzuki, Norihiro; Chang, Yung; Yamauchi, Yusuke; Lin, Feng-Huei; Wu, Kevin C-W

    2015-01-01

    Hyperthermia is one of the promising treatments for cancer therapy. However, the development of a magnetic fluid agent that can selectively target a tumor and efficiently elevate temperature while exhibiting excellent biocompatibility still remains challenging. Here a new core-shell nanostructure consisting of inorganic iron oxide (Fe3O4) nanoparticles as the core, organic alginate as the shell, and cell-targeting ligands (ie, D-galactosamine) decorated on the outer surface (denoted as Fe3O4@Alg-GA nanoparticles) was prepared using a combination of a pre-gel method and coprecipitation in aqueous solution. After treatment with an AC magnetic field, the results indicate that Fe3O4@Alg-GA nanoparticles had excellent hyperthermic efficacy in a human hepatocellular carcinoma cell line (HepG2) owing to enhanced cellular uptake, and show great potential as therapeutic agents for future in vivo drug delivery systems. PMID:26005343

  9. Constructing a novel zwitterionic surface of PVDF membrane through the assembled chitosan and sodium alginate.

    Science.gov (United States)

    Wang, Haiye; Zhao, Xinzhen; He, Chunju

    2016-06-01

    A novel zwitterionic surface of PVDF membrane with significantly improved antifouling properties was prepared though pressure-assisted layer by layer self-assembly method based on the electrostatic interactions of chitosan (CS), sodium alginate (SA) and polyfunctional lysine. For the modified C-S-C-S-L membrane, the contact angle decreased to 35°, the bovine serum albumin (BSA) adsorption mass of static fouling on the membrane surface decreased to 10μg/cm(2), and the secondary water flux recovery rate (FRR) of dynamic fouling of BSA and humic acid (HA) pollutants increased to 98% and 99%, respectively, exhibiting excellent antifouling performance. The results demonstrated that using charged bio-macromolecules and amino acids to build zwitterionic surface was effective and convenient to change the interface properties of the separation membrane through the pressure-assisted self-assembly modification method, and provided a new way for the industrial scale hydrophilic modification of hydrophobic porous membrane materials. PMID:26944663

  10. Removal of copper ions from aqueous solution by calcium alginate immobilized kaolin

    Institute of Scientific and Technical Information of China (English)

    Yanhui Li; Yanzhi Xia; Bing Xia; Quansheng Zhao; Fuqiang Liu; Pan Zhang; Qiuju Du; Dechang Wang; Da Li; Zonghua Wang

    2011-01-01

    Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The effects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.

  11. Polyelectrolyte complex nanoparticles from cationised gelatin and sodium alginate for curcumin delivery.

    Science.gov (United States)

    Sarika, P R; James, Nirmala Rachel

    2016-09-01

    Self assembled hybrid polyelectrolyte complex (PEC) nanoparticles are prepared from cationically modified gelatin and sodium alginate (Alg) by electrostatic complexation between the polymers. Cationised gelatin (CG) is prepared by the reaction of gelatin with ethylenediamine. Structural changes in gelatin, after modification with ethylenediamine are investigated by XRD and (1)H NMR spectroscopy. Hybrid polyelectrolyte nanoparticles, labeled CG/Alg, are prepared by simple mixing of CG and Alg. CG/Alg complex shows spherical morphology as confirmed by scanning electron microscopy. These polyelectrolyte complex nanoparticles can be used for the encapsulation and delivery of natural antioxidant curcumin to carcinoma cells. CG/Alg nanoparticles show curcumin encapsulation efficiency of 69% and exhibit sustained release of curcumin in vitro. Anticancer activity of curcumin loaded CG/Alg nanoparticles towards MCF-7 cells is disclosed by MTT assay. Intracellular uptake of the drug encapsulated nanoparticles is confirmed by fluorescent imaging. PMID:27185149

  12. Interaction of Green Polymer Blend of Modified Sodium Alginate and Carboxylmethyl Cellulose Encapsulation of Turmeric Extract

    Directory of Open Access Journals (Sweden)

    Sa-Ad Riyajan

    2013-01-01

    Full Text Available Turmeric extract (tmr loaded nanoparticles were prepared by crosslinking modified carboxylmethyl cellulose (CMC and modified sodium alginate (SA with calcium ions, in a high pressure homogenizer. The FTIR spectra of CMC and SA were affected by blending due to hydrogen bonding. The negative zeta potential increased in magnitude with CMC content. The smallest nanoparticles were produced with a 10 : 5 SA/CMC blend. Also the release rates of the extract loading were measured, with model fits indicating that the loading level affected the release rate through nanoparticle structure. The 10 : 5 SA/CMC blend loading with tmr and pure tmr showed a good % growth inhibition of colon cancer cells which indicate that tmr in the presence of curcumin in tmr retains its anticancer activity even after being loaded into SA/CMC blend matrix.

  13. Polyurethane and alginate immobilized algal biomass for the removal of aqueous toxic metals

    International Nuclear Information System (INIS)

    We describe the development of immobilized, processed algal biomass for use as an adsorptive filter in the removal of toxic metals from waste water. To fabricate an adsorptive filter from precessed biomass several crucial criteria must be met, including: (1) high metal binding capacity, (2) long term stability (both mechanical and chemical), (3) selectivity for metals of concern (with regard to ionic competition), (4) acceptable flow capacity (to handle large volumes in short time frames), (5) stripping/regeneration (to recycle the adsorptive filter and concentrate the toxic metals to manageable volumes). This report documents experiments with processed algal biomass (Spirulina platensis and Spirulina maxima) immobilized in either alginate gel or preformed polyurethane foam. The adsorptive characteristics of these filters were assessed with regard to the criteria listed above

  14. Development and evaluation of calcium alginate beads prepared by sequential and simultaneous methods

    Directory of Open Access Journals (Sweden)

    Sanchita Mandal

    2010-12-01

    Full Text Available The objective of this study was to develop a sustained release dosage form of Trimetazidine dihydrochloride (TMZ using a natural polymeric carrier prepared in a completely aqueous environment. TMZ was entrapped in calcium alginate beads prepared with sodium alginate by the ionotropic gelation method using calcium chloride as a crosslinking agent. The drug was incorporated either into preformed calcium alginate gel beads (sequential method or incorporated simultaneously during the gelation stage (simultaneous method. The beads were evaluated for particle size and surface morphology using optical microscopy and SEM, respectively. Beads produced by the sequential method had higher drug entrapment. Drug entrapment in the sequential method was higher with increased CaCl2 and polymer concentration but lower with increased drug concentration. In the simultaneous method, drug entrapment was higher when polymer and drug concentration were increased and also rose to a certain extent with increase in CaCl2 concentration, where further increase resulted in lower drug loading. FTIR studies revealed that there is no interaction between drug and CaCl2. XRD studies showed that the crystalline drug changed to an amorphous state after formulation. Release characteristics of the TMZ loaded calcium alginate beads were studied in enzyme-free simulated gastric and intestinal fluid.O objetivo deste estudo foi desenvolver forma de liberação controlada de dicloridrato de trimetazidina (TMZ utilizando transportador plomérico natural em ambiente completamente aquoso. A TMZ foi presa em pérolas de alginato de cálcio preparadas com alginato de sódio pelo método de gelatinização ionotrópica, usando cloreto de cálcio como agente de formação de ligações cruzadas. O fármaco foi incorporado nas pérolas de gel de alginato de cálcio (método sequencial ou incorporado, simultaneamente, durante o estágio de gelificação (método simultâneo. As pérolas foram

  15. Preparation and characterization of crosslinked alginate-CMC beads for controlled release of nitrate salt

    International Nuclear Information System (INIS)

    Carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were successfully prepared by Ca2+ ions crosslinking followed by gamma irradiation. The factors affecting beads formation are the composition of SA in the blend and concentration of calcium chloride as a crosslinking agent. The results indicated that the addition of CMC to SA increases the swelling (%) upto (1:3) (CMC:SA) ratio. The effect of different irradiation doses (2.5, 5, and 10 kGy) on swelling (%) was studied. At low doses, swelling (%) decreases upto 5 kGy then starts to increase at 10 kGy. The degree of the swelling (%) and release (%) of ammonium nitrate salt from beads were investigated under different pH (1.2, 5 and 7). The beads were characterized by FTIR, SEM and TGA to investigate molecular structure, morphology and thermal stability of beads. (author)

  16. Uranium uptake by Chitosan impregnated in calcium alginate from potable water

    International Nuclear Information System (INIS)

    Chitosan, a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit) was effectively immobilized in sodium alginate in the form of beads by using 0.2 M calcium chloride solution. These beads were used to reduce the concentration of uranium from 1000 μgmL-1 to < 10 ppb at pH 5. Ground water qualities were monitored before and after the treatment with the beads. ATRFTIR spectrum of uranium loaded beads of chitosan indicates that U(VI) binds to the amine group. These amino sites in chitosan groups are mainly responsible for the binding of U(VI) by formation of uranium-amine complex. (author)

  17. Influence of carboxymethyl cellulose and sodium alginate on sweetness intensity of Aspartame.

    Science.gov (United States)

    Han, Xue; Xu, Shu-Zhen; Dong, Wen-Rui; Wu, Zhai; Wang, Ren-Hai; Chen, Zhong-Xiu

    2014-12-01

    Sensory evaluation of Aspartame in the presence of sodium carboxymethyl cellulose (CMC-L) and sodium alginate (SA) revealed that only CMC-L showed a suppression effect, while SA did not. By using an artificial taste receptor model, we found that the presence of SA or CMC-L resulted in a decrease in association constants. Further investigation of CMC-L solution revealed that the decrease in water mobility and diffusion also contribute to the suppression effect. In the case of SA, the decreased viscosity and comparatively higher amount of free water facilitated the diffusion of sweetener, which might compensate for the decreased binding constant between Aspartame and receptor. This may suppress the impact of SA on sweetness intensity. The results suggest that exploring the binding affinity of taste molecules with the receptor, along with water mobility and diffusion in hydrocolloidal structures, provide sufficient information for understanding the mechanism behind the effect of macromolecular hydrocolloids on taste. PMID:24996335

  18. Development of alginate microspheres containing thyme essential oil using ionic gelation.

    Science.gov (United States)

    Benavides, Sergio; Cortés, Pablo; Parada, Javier; Franco, Wendy

    2016-08-01

    Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000rpm/5min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. PMID:26988478

  19. Kojic acid production from cocoa juice by Aspergillus flavus entrapped in calcium alginate.

    Science.gov (United States)

    el-Sharkawy, S H

    1995-06-01

    Sixteen microorganisms of Aspergillus strains were screened for production of kojic acid using cocoa juice as carbon source. Only Aspergillus flavus ATCC 9179 was found to produce the acid in low yield (22 mg/ml). Calcium alginate immobilization of the cells was used under optimum conditions to maximize the yield of kojic acid (60 mg/ml). Cultures were incubated in the medium with 50% of cocoa juice added in pulses of 8 ml each every 96 hours, and 4% methanol, pH 3.5, 150 rpm, 26 degrees C for three weeks. The incubations were monitored by thin layer and high pressure liquid chromatography. Kojic acid was extracted from the culture broth by organic solvent, concentrated and crystallized. The chemical identity of kojic acid was determined by HPLC, MS, 1H- and 13C-NMR spectroscopy. PMID:7546538

  20. Preparation of superparamagnetic sodium alginate nanoparticles for covalent immobilization of Candida rugosa lipase

    International Nuclear Information System (INIS)

    Superparamagnetic sodium alginate nanoparticles with diameter around 25–30 nm were prepared with a water-in-oil emulsion method. The resulted magnetic SA nanoparticle was activated with glutaraldehyde and epichlorohydrin to form nanoscale support. Candida rugosa lipase (CRL), hereby chosen as a model enzyme, was covalently immobilized on the resulted magnetic support. The structure and magnetic behavior of the magnetic nanoparticles were confirmed by transmission electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. Based on the structural character of enzyme (containing functional residues that are ideal reaction sites for the immobilization of enzyme repeatedly), the regeneration of support was investigated by reactivating the deactivated immobilized lipase with glutaraldehyde. And the results indicated that these regenerated supports remained to be efficient for lipase immobilization. Finally, all of the immobilized CRL prepared by different generations of supports displayed excellent reusability and applicability.

  1. Preparation of superparamagnetic sodium alginate nanoparticles for covalent immobilization of Candida rugosa lipase

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiao; Chen Xia; Li Yanfeng, E-mail: liyf@lzu.edu.cn; Cui Yanjun; Zhu Hao; Zhu Weiwei [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China)

    2012-03-15

    Superparamagnetic sodium alginate nanoparticles with diameter around 25-30 nm were prepared with a water-in-oil emulsion method. The resulted magnetic SA nanoparticle was activated with glutaraldehyde and epichlorohydrin to form nanoscale support. Candida rugosa lipase (CRL), hereby chosen as a model enzyme, was covalently immobilized on the resulted magnetic support. The structure and magnetic behavior of the magnetic nanoparticles were confirmed by transmission electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. Based on the structural character of enzyme (containing functional residues that are ideal reaction sites for the immobilization of enzyme repeatedly), the regeneration of support was investigated by reactivating the deactivated immobilized lipase with glutaraldehyde. And the results indicated that these regenerated supports remained to be efficient for lipase immobilization. Finally, all of the immobilized CRL prepared by different generations of supports displayed excellent reusability and applicability.

  2. A NOVEL BIO-WASTE INCORPORATED ALGINATE SORBENT FOR DE-FLUORIDATION OF WATER

    Directory of Open Access Journals (Sweden)

    Carmalin Sophia Ayyappan

    2015-09-01

    Full Text Available This study evaluates the feasibility of using tamarind (Tamarindus indica seed powder for de-fluoridation of fluoride contaminated water. Batch study confirmed that tamarind seeds in dry powder form could remove 87% of fluoride from water. This bio-sorbent can be used effectively in areas where fluoride concentrations are above the permissible limits of 1.5 mg·l-1 as per WHO Standard, 1984. Tamarind seed powder was incorporated in a matrix of sodium alginate and made into gel-beads. The beads were tested for de-fluoridation efficiency by conducting column studies. The effect of various factors, such as flow rate, retention time, and the number of runs on the efficacy of fluoride removal was also studied. The results revealed that flow rate did not seem to have much effect on the percentage fluoride removal but the fluoride concentration decreased drastically upon greater retention time and multiple runs.

  3. Development of silver sulfadiazine loaded bacterial cellulose/sodium alginate composite films with enhanced antibacterial property.

    Science.gov (United States)

    Shao, Wei; Liu, Hui; Liu, Xiufeng; Wang, Shuxia; Wu, Jimin; Zhang, Rui; Min, Huihua; Huang, Min

    2015-11-01

    Sodium alginate (SA) and bacterial cellulose (BC) are widely used in many applications such as scaffolds and wound dressings due to its biocompatibility. Silver sulfadiazine (AgSD) is a topical antibacterial agents used as a topical cream on burns. In the study, novel BC/SA-AgSD composites were prepared and characterized by SEM, FTIR and TG analyses. These results indicate AgSD successfully impregnated into BC/SA matrix. The swelling behaviors in different pH were studied and the results showed pH-responsive swelling behaviors. The antibacterial performances of BC/SA-AgSD composites were evaluated with Escherichia coli, Staphylococcus aureus and Candida albicans. Moreover, the cytotoxicity of BC/SA-AgSD composites was performed on HEK 293 cells. The experimental results showed BC/SA-AgSD composites have excellent antibacterial activities and good biocompatibility, thus confirming its utility as potential wound dressings. PMID:26256359

  4. Functionalized magnetic iron oxide/alginate core-shell nanoparticles for targeting hyperthermia

    Directory of Open Access Journals (Sweden)

    Liao SH

    2015-05-01

    Full Text Available Shih-Hsiang Liao,1 Chia-Hung Liu,2 Bishnu Prasad Bastakoti,3 Norihiro Suzuki,7 Yung Chang,4 Yusuke Yamauchi,3 Feng-Huei Lin,5,6 Kevin C-W Wu1,6 1Department of Chemical Engineering, National Taiwan University No 1, Taipei, 2Department of Urology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; 3National Institute for Materials Science, Ibaraki, Japan; 4R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Taoyua, 5Institute of Biomedical Engineering, National Taiwan University No 1, Taipei City, 6Division of Medical Engineering Research, National Health Research Institutes, Miaoli County, Taiwan, 7International Center for Young Scientists (ICYS, National Institute for Materials Science (NIMS, Tsukuba, Ibaraki, Japan Abstract: Hyperthermia is one of the promising treatments for cancer therapy. However, the development of a magnetic fluid agent that can selectively target a tumor and efficiently elevate temperature while exhibiting excellent biocompatibility still remains challenging. Here a new core-shell nanostructure consisting of inorganic iron oxide (Fe3O4 nanoparticles as the core, organic alginate as the shell, and cell-targeting ligands (ie, D-galactosamine decorated on the outer surface (denoted as Fe3O4@Alg-GA nanoparticles was prepared using a combination of a pre-gel method and coprecipitation in aqueous solution. After treatment with an AC magnetic field, the results indicate that Fe3O4@Alg-GA nanoparticles had excellent hyperthermic efficacy in a human hepatocellular carcinoma cell line (HepG2 owing to enhanced cellular uptake, and show great potential as therapeutic agents for future in vivo drug delivery systems. Keywords: hyperthermia, iron oxide, alginate, pre-gel, targeting 

  5. In situ coronary stent paving by Pluronic F127-alginate gel blends: Formulation and erosion tests.

    Science.gov (United States)

    Dalmoro, Annalisa; Barba, Anna Angela; Grassi, Mario; Grassi, Gabriele; Lamberti, Gaetano

    2016-07-01

    In this work the development of an experimental protocol to perform the in situ gel-paving of coronary stent is presented. Biocompatible aqueous blends of Pluronic F127 and sodium alginates are used as potential drug dosage system for pharmacological in situ treatment of coronary in-stent restenosis. Pluronic F127/alginate aqueous blend has the unique characteristic to be liquid at room condition and to form gel at physiological temperature. The proposed protocol is based on the blend injection on stent wall previously implanted in a flexible silicon pipe mimicking the coronary artery. Injected blend is warmed up until human body temperature achieving a soft gel, then it is reticulated by copper bivalent ions to obtain an hard gel. To test the gel paving resistance to erosion phenomena when it is exposed to fluid flux (i.e. blood flux) a dedicated device, (the Simulated Artery Device, SAD), was built to simulate the human circulatory apparatus. The SAD is an hydraulic circuit in which a buffer solution (at pH 7.4) was fluxed by a peristaltic pump through the pipe hosting the covered stent. Erosion tests were performed monitoring, by gravimetric and spectrophotometric methods, the residual mass anchored to stent mesh after given times. The obtained results showed that the in situ gel-paving developed protocol was efficacious and reliable. The gel-paving was completely eroded in a time of the same order of magnitude of the physiological period required to restore the coronary lesion (subsequent to the atheroma removal) and of a pharmacological therapy to inhibit the in-stent-restenosis pathology. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1013-1022, 2016. PMID:25997168

  6. Morphogenetically active scaffold for osteochondral repair (polyphosphate/alginate/N,O-carboxymethyl chitosan).

    Science.gov (United States)

    Müller, W E; Neufurth, M; Wang, S; Tolba, E; Schröder, H C; Wang, X

    2016-01-01

    Here we describe a novel bioinspired hydrogel material that can be hardened with calcium ions to yield a scaffold material with viscoelastic properties matching those of cartilage. This material consists of a negatively charged biopolymer triplet, composed of morphogenetically active natural inorganic polyphosphate (polyP), along with the likewise biocompatible natural polymers N,O-carboxymethyl chitosan (N,O-CMC) and alginate. The porosity of the hardened scaffold material obtained after calcium exposure can be adjusted by varying the pre-processing conditions. Various compression tests were applied to determine the local (nanoindentation) and bulk mechanical properties (tensile/compression test system for force measurements) of the N,O-CMC-polyP-alginate material. Determinations of the Young's modulus revealed that the stiffness of this comparably water rich (and mouldable) material increases during successive compression cycles to values measured for native cartilage. The material not only comprises viscoelastic properties suitable for a cartilage substitute material, but also displays morphogenetic activity. It upregulates the expression of genes encoding for collagen type II and aggrecan, the major proteoglycan within the articular cartilage, in human chondrocytes, and the expression of alkaline phosphatase in human bone-like SaOS-2 cells, as revealed in RT qPCR experiments. Further, we demonstrate that the new polyP-based material can be applied for manufacturing 3D solid models of cartilage bone such as of the tibial epiphyseal plate and the superior articular cartilage surface. Since the material is resorbable and enhances the activity of cells involved in regeneration of cartilage tissue, this material has the potential to be used for artificial articular cartilage implants. PMID:26898843

  7. pH-sensitive Laponite(®)/doxorubicin/alginate nanohybrids with improved anticancer efficacy.

    Science.gov (United States)

    Gonçalves, Mara; Figueira, Priscilla; Maciel, Dina; Rodrigues, João; Qu, Xue; Liu, Changsheng; Tomás, Helena; Li, Yulin

    2014-01-01

    The efficacy of the anticancer drug doxorubicin (Dox) is limited by an insufficient cellular uptake and drug resistance, which is partially due to ion trapping in acidic environments such as the extracellular environment of solid tumors and the interior of endolysosome vesicles. Herein, we describe the preparation and in vitro evaluation of a new type of nanohybrid for anticancer drug delivery which is capable of carrying a high load of the cationic Dox through the cell membrane. In addition, the nanohybrids use the acidic environment of the endolysosomes to release the drug, simultaneously helping to disrupt the endolysosomes and diminishing endolysosome Dox trapping. Furthermore, as the nanohybrid carriers are capable of sustained drug delivery, those that remain in the cytoplasm and still contain Dox are expected to exert a prolonged anticancer activity. Briefly, Dox is loaded onto biocompatible anionic Laponite(®) (LP) nanodisks with a high aspect ratio (25 nm in diameter and 0.92 nm in thickness) through strong electrostatic interactions to get Dox-loaded LP disks. Alginate (AG), a biocompatible natural polymer, is then coated onto the Dox-loaded LP disks (LP/Dox/AG nanohybrids) to prevent the burst release of the drug. The results demonstrate that the nanohybrids have a high encapsulation efficiency (80.8 ± 10.6%), are sensitive to pH and display a sustained drug release behavior. Cell culture experiments indicate that the LP/Dox/AG nanohybrids can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher cytotoxicity to cancer cells than the free Dox. The merits of Laponite(®)/alginate nanohybrids, such as biocompatibility, high loading capacity and stimulus responsive release of cationic chemotherapeutic drugs, render them as excellent platforms for drug delivery. PMID:24075886

  8. Release profile and stability evaluation of optimized chitosan/alginate nanoparticles as EGFR antisense vector

    Directory of Open Access Journals (Sweden)

    Ebrahim Azizi

    2010-06-01

    Full Text Available Ebrahim Azizi1,4, Alireza Namazi1, Ismaeil Haririan2,5, Shamileh Fouladdel1, Mohammad R Khoshayand3, Parisa Y Shotorbani6, Alireza Nomani1,7, Taraneh Gazori1,21Molecular Research Lab, Department of Pharmacology and Toxicology, 2Department of Pharmaceutics, 3Department of Food and Drug Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 4Department of Medical Biotechnology, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran, Iran; 5Biomaterials Research Center (BRC Tehran, Iran; 6Pharmaceutical Sciences Branch, Azad University, Tehran, Iran; 7Department of Pharmaceutics, Faculty of Pharmacy, Zanjan University of Medical Sciences, Zanjan, IranAbstract: Chitosan/alginate nanoparticles which had been optimized in our previous study using two different N/P ratios were chosen and their ability to release epidermal growth factor receptor (EGFR antisense was investigated. In addition, the stability of these nanoparticles in aqueous medium and after freeze-drying was investigated. In the case of both N/P ratios (5, 25, nanoparticles started releasing EGFR antisense as soon as they were exposed to the medium and the release lasted for approximately 50 hours. Nanoparticle size, shape, zeta potential, and release profile did not show any significant change after the freeze-drying process (followed by reswelling. The nanoparticles were reswellable again after freeze-drying in phosphate buffer with a pH of 7.4 over a period of six hours. Agarose gel electrophoresis of the nanoparticles with the two different N/P ratios showed that these nanoparticles could protect EGFR antisense molecules for six hours.Keywords: chitosan/alginate nanoparticles, release profile, freeze-drying, agarose gel electrophoresis

  9. Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads

    International Nuclear Information System (INIS)

    Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH0, ΔS0 and ΔG0 were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous. -- Highlights: • Equilibrium, kinetics and thermodynamics of uranium sorption by CaAlg were studied. • Equilibrium studies show that Langmuir isotherm better fit with experimental data. • Pseudo-second-order kinetics model is found to be well depicting the kinetic data. • Thermodynamic study shows that the sorption process is endothermic and spontaneous

  10. Hydroxyapatite-alginate biocomposite promotes bone mineralization in different length scales in vivo

    Institute of Scientific and Technical Information of China (English)

    E L.DE PAULA; I.C.BARRETO; M.H.ROCHA-LE(A)O; R.BOROJEVIC; A.M.ROSSIA; F.P.ROSA; M.FARINA

    2009-01-01

    Tissue engineering is a multidisciplinary research area that aims to develop new techniques and/or biomaterials for medical applications. The objective of thepresent study was to evaluate the osteogenic potential of a composite of hydroxyapatite and alginate in bone defects with critical sizes, surgically made in the calvaria region of rats. The rats (48 adult males), Rattus norvegicus Wistar,were divided into two groups: control (without composite implantation) and experimental (with composite implanta-tion) and analyzed by optical microscopy at the biological time points 15, 45, 90 and 120 d, and transmission electron microscopy 120 d after file implantation of the biomaterinl.It was observed that the biomaterial presented a high degree of fragmentation since the first experilnental points studied, and that the fragments were surrounded by new bone after the duration of the project. These areas were studied by analytical transmission electron microscopy using an energy thsperslve X-ray spectrometer, Three regions could be distinguished: (1) the biomaterial rich in hydroxyapatite; (2) a thin contiguous region containing phosphorus but without calcium; (3) a region of initial ossification containing mineralizing collagen fibrils with a calcium/phosphorus ratio smaller than the particles of the composite. The intermediate region (without calcium or containing very low amounts of calcium), which just surrounded the cothposite had not been described in the hterature yet. And is probably associated specitically to the biocomposite used. The high performance of the bioma-terial observed may be related to the fact that alginate molecules form highly anionic complexes and are capable of adsorbing important factors recognized by integrins from osteoblasts. Regions of fibrotic tissue were also observed mainly in theinitial experimental points analyzed. However, it did not significantly influence the final result. In conclusion, the biomaterial presents a great potential for

  11. Biochemical and structural characterization of neocartilage formed by mesenchymal stem cells in alginate hydrogels.

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    Magnus Ø Olderøy

    Full Text Available A popular approach to make neocartilage in vitro is to immobilize cells with chondrogenic potential in hydrogels. However, functional cartilage cannot be obtained by control of cells only, as function of cartilage is largely dictated by architecture of extracellular matrix (ECM. Therefore, characterization of the cells, coupled with structural and biochemical characterization of ECM, is essential in understanding neocartilage assembly to create functional implants in vitro. We focused on mesenchymal stem cells (MSC immobilized in alginate hydrogels, and used immunohistochemistry (IHC and gene expression analysis combined with advanced microscopy techniques to describe properties of cells and distribution and organization of the forming ECM. In particular, we used second harmonic generation (SHG microscopy and focused ion beam/scanning electron microscopy (FIB/SEM to study distribution and assembly of collagen. Samples with low cell seeding density (1e7 MSC/ml showed type II collagen molecules distributed evenly through the hydrogel. However, SHG microscopy clearly indicated only pericellular localization of assembled fibrils. Their distribution was improved in hydrogels seeded with 5e7 MSC/ml. In those samples, FIB/SEM with nm resolution was used to visualize distribution of collagen fibrils in a three dimensional network extending from the pericellular region into the ECM. In addition, distribution of enzymes involved in procollagen processing were investigated in the alginate hydrogel by IHC. It was discovered that, at high cell seeding density, procollagen processing and fibril assembly was also occurring far away from the cell surface, indicating sufficient transport of procollagen and enzymes in the intercellular space. At lower cell seeding density, the concentration of enzymes involved in procollagen processing was presumably too low. FIB/SEM and SHG microscopy combined with IHC localization of specific proteins were shown to provide

  12. Detoxification of Hg(II) from aqueous and enzyme media: Pristine vs. tailored calcium alginate hydrogels.

    Science.gov (United States)

    Sarkar, Kangkana; Ansari, Zarina; Sen, Kamalika

    2016-10-01

    Calcium alginate (CA) hydrogels were tailored using phenolic compounds (PC) like, thymol, morin, catechin, hesperidin, during their preparation. The PC incorporated gels show modified surface features as indicated by scanning electron microscopic images (SEM). The rheological studies show that excepting the hesperidin incorporated gels all the other kinds including calcium alginate pristine have similar mechanical strength. The hesperidine incorporated CA gels had the maximum capacity to adsorb Hg. The Freundlich adsorption isotherms show higher values of adsorption capacity for all PC incorporated CA beads than the pristine CA (PCA). The hesperidin incorporated CA gels were found to show the best adsorption condition at neutral pH and an optimum contact time of 2.5h at 25°C. Considering the possibility of ingested Hg detoxification from human alimentary tract, the hesperidin and morin incorporated CA beads were further modified through incorporation of cod liver oil as the digestion time of fat in stomach is higher. In vitro uptake capacities of Hg in pepsin and pancreatin containing enzyme media were studied with hesperidin and morin incorporated beads and their corresponding fat incorporated beads also. In the pepsin medium, there was no uptake by hesperidin and fat-hesperidin incorporated beads, which is possibly due to the higher acidity of the medium. But in pancreatin medium Hg was taken up by both kinds of beads. Morin and morin-fat incorporated beads were efficient to uptake Hg from both the pepsin and pancreatin medium. The tailored CA beads may therefore serve as efficient scaffolds to rescue Hg ingested individuals. PMID:27208797

  13. The Efficiency of Vascular Embolization Using Alginate Gel : An Experimental Study in Rabbit

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woo Baek; Kang, Yeong Han [Dept. of Diagnostic Radiology, Daegu Catholic University Hospital, Daegu (Korea, Republic of); Kim, Jong Ki [Dept. of Biomedical Engineering, Daegu Catholic University, Daegu (Korea, Republic of)

    2009-03-15

    The purpose of this study was to investigate the applicability of poly-L-guluronic alginate (PGA) gel in vascular embolization with angiography simulation. To prepare a gel-forming PGA from no guluronate-rich Laminaria japonica, a new acid hydrolysis method was employed with a lower HCL concentration (0.03 M) and a shorter treatment time (5 min). The obtained PGAs were selected based on gel stability and viscosity. Glass aneurysm model was used to simulate gel embolization in vitro. Then, finally, the PGA was used to embolize the renal vascular system by using a rabbit model and angiography. Glass aneurysm model was made to simulate gel embolization procedure. PGA solution was injected from pump through 2-way catheter. Subsequent injection of CaCl{sub 2} successfully formed gels inside aneurysm model that conforming to its inner contour. In rabbit model, first, renal artery and aorta leading to the right kidney were ligated to block blood flow, then conventional contrast agent was injected through aorta to check the arterial patency to the left kidney. In sequential artery injection method, PGA and CaCl{sub 2} were injected through renal artery sequentially via a single catheter. Re-injection of contrast agent after removing ligated aorta showed blood flow to the right kidney but no flow in the left kidney. This result demonstrated a complete blocking of blood flow due to gel formation in vascular bed of the left kidney. Instillation of calcium alginate into aneurysm model and arterial system in vivo produced an embolization that better fills and conforms to the contour of aneurysms or blocking vascular bed completely. Therefore, PGA was effective endovascular occlusion materials and provide an efficiency of vascular angiography.

  14. The Efficiency of Vascular Embolization Using Alginate Gel : An Experimental Study in Rabbit

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the applicability of poly-L-guluronic alginate (PGA) gel in vascular embolization with angiography simulation. To prepare a gel-forming PGA from no guluronate-rich Laminaria japonica, a new acid hydrolysis method was employed with a lower HCL concentration (0.03 M) and a shorter treatment time (5 min). The obtained PGAs were selected based on gel stability and viscosity. Glass aneurysm model was used to simulate gel embolization in vitro. Then, finally, the PGA was used to embolize the renal vascular system by using a rabbit model and angiography. Glass aneurysm model was made to simulate gel embolization procedure. PGA solution was injected from pump through 2-way catheter. Subsequent injection of CaCl2 successfully formed gels inside aneurysm model that conforming to its inner contour. In rabbit model, first, renal artery and aorta leading to the right kidney were ligated to block blood flow, then conventional contrast agent was injected through aorta to check the arterial patency to the left kidney. In sequential artery injection method, PGA and CaCl2 were injected through renal artery sequentially via a single catheter. Re-injection of contrast agent after removing ligated aorta showed blood flow to the right kidney but no flow in the left kidney. This result demonstrated a complete blocking of blood flow due to gel formation in vascular bed of the left kidney. Instillation of calcium alginate into aneurysm model and arterial system in vivo produced an embolization that better fills and conforms to the contour of aneurysms or blocking vascular bed completely. Therefore, PGA was effective endovascular occlusion materials and provide an efficiency of vascular angiography.

  15. Synthesis of Quercetin Loaded Nanoparticles Based on Alginate for Pb(II) Adsorption in Aqueous Solution

    Science.gov (United States)

    Qi, Yun; Jiang, Meng; Cui, Yuan-Lu; Zhao, Lin; Zhou, Xia

    2015-10-01

    Pb(II) is a representative heavy metal in industrial wastewater, which may frequently cause serious hazard to living organisms. In this study, comparative studies between alginate nanoparticles (AN) and quercetin-decorated alginate nanoparticles (Q-AN) were investigated for Pb(II) ion adsorption. Characterization of AN and Q-AN were analysed by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffractometer (XRD), and thermogravimetric analysis (TG-DTG-DSC). The main operating conditions such as pH, initial concentration of Pb(II), and co-existing metal ions were also investigated using a batch experiment. AN and Q-AN, with a diameter of 95.06 and 58.23 nm, were constituted by many small primary nanoparticles. It revealed that when initial concentration of Pb(II) is between 250 and 1250 mg L-1, the adsorption rate and equilibrium adsorption were increased with the increase of pH from 2 to 7. The maximum adsorption capacities of 147.02 and 140.37 mg L-1 were achieved by AN and Q-AN, respectively, with 0.2 g adsorbents in 1000 mg L-1 Pb(II) at pH 7. The adsorption rate of Pb(II) was little influenced by the co-existing metal ions, such as Mn(II), Co(II), and Cd(II). Desorption experiments showed that Q-AN possessed a higher desorption rate than AN, which were 90.07 and 83.26 %, respectively. AN and Q-AN would probably be applied as adsorbents to remove Pb(II) and then recover it from wastewater for the advantages of simple preparation, high adsorption capacity, and recyclability.

  16. Innate immune-stimulating and immune genes up-regulating activities of three types of alginate from Sargassum siliquosum in Pacific white shrimp, Litopenaeus vannamei.

    Science.gov (United States)

    Yudiati, Ervia; Isnansetyo, Alim; Murwantoko; Ayuningtyas; Triyanto; Handayani, Christina Retna

    2016-07-01

    The Total Haemocyte Count (THC), phenoloxidase (PO), Superoxide Dismutase (SOD) activity, Phagocytic Activity/Index and Total Protein Plasma (TPP) were examined after feeding the white shrimp Litopenaeus vannamei with diets supplemented with three different types of alginates (acid, calcium and sodium alginates). Immune-related genes expression was evaluated by quantitative Real Time PCR (qRT-PCR). Results indicated that the immune parameters directly increased according to the doses of alginates and time. The 2.0 g kg(-1) of acid and sodium alginate treatments were gave better results. Four immune-related genes expression i.e. LGBP, Toll, Lectin, proPO were up regulated. It is therefore concluded that the supplementation of alginate of Sargassum siliquosum on the diet of L. vannamei enhanced the innate immunity as well as the expression of immune-related genes. It is the first report on the simultaneous evaluation of three alginate types to enhance innate immune parameters and immune-related genes expression in L. vannamei. PMID:26993614

  17. Drug carrier systems based on collagen-alginate composite structures for improving the performance of GDNF-secreting HEK293 cells.

    Science.gov (United States)

    Lee, M; Lo, A C; Cheung, P T; Wong, D; Chan, B P

    2009-02-01

    Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor. Development of drug delivery technologies facilitating controlled release of GDNF is critical to applying GDNF in treating neurodegenerative diseases. We previously developed 3D collagen microspheres and demonstrated enhanced GDNF secretion after encapsulation of HEK293 cells, which were transduced to overexpress GDNF in these microspheres. However, the entrapped HEK293 cells were able to migrate out of the collagen microspheres, making it undesirable for clinical applications. In this report, we investigate two new carrier designs, namely collagen-alginate composite gel and collagen microspheres embedded in alginate gel in preventing cell leakage, maintaining cell growth and controlling GDNF secretion in the HEK293 cells. We demonstrated that inclusion of alginate gel in both designs is efficient in preventing cell leakage to the surrounding yet permitting the GDNF secretion, although the cellular growth rate is reduced in an alginate concentration dependent manner. Differential patterns of GDNF secretion in the two designs were demonstrated. The collagen-alginate composite gel maintains a more or less constant GDNF secretion over time while the collagen microspheres embedded in alginate gel continue to increase the secretion level of GDNF over time. This study contributes towards the development of cell-based GDNF delivery devices for the future therapeutics of neurodegenerative diseases. PMID:19059641

  18. Generation of continuous packed bed reactor with PVA–alginate blend immobilized Ochrobactrum sp. DGVK1 cells for effective removal of N,N-dimethylformamide from industrial effluents

    International Nuclear Information System (INIS)

    Highlights: ► Removal of DMF was compared by free and immobilized cells of Ochrobactrum sp. DGVK1. ► Ochrobactrum sp. DGVK1 cells entrapped in PVA–alginate have shown more tolerance. ► PVA–alginate beads removed DMF even in the presence of other organic solvents. ► Removal of DMF from industrial effluents by PVA–alginate blended batch operations. ► Development of industrially feasible remediation strategy for DMF removal. - Abstract: Effective removal of dimethylformamide (DMF), the organic solvent found in industrial effluents of textile and pharma industries, was demonstrated by using free and immobilized cells of Ochrobactrum sp. DGVK1, a soil isolate capable of utilizing DMF as a sole source of carbon, nitrogen. The free cells have efficiently removed DMF from culture media and effluents, only when DMF concentration was less than 1% (v/v). Entrapment of cells either in alginate or in polyvinyl alcohol (PVA) failed to increase tolerance limits. However, the cells of Ochrobactrum sp. DGVK1 entrapped in PVA–alginate mixed matrix tolerated higher concentration of DMF (2.5%, v/v) and effectively removed DMF from industrial effluents. As determined through batch fermentation, these immobilized cells have retained viability and degradability for more than 20 cycles. A continuous packed bed reactor, generated by using PVA–alginate beads, efficiently removed DMF from industrial effluents, even in the presence of certain organic solvents frequently found in effluents along with DMF.

  19. Use of antioxidants substances to protect the hydrocolloids carrageenan, agaran and alginates used in food industry when exposed to radiation

    International Nuclear Information System (INIS)

    Carrageenan, agaran e alginates are hydrocolloids largely employed in every kind of food products as stabilizing agent and viscosity builder. The human body does not absorb them, so they do not introduce extra calories in the diet. Irradiation is presented as an important alternative method in food preservation because do not induce temperature increase being of good efficiency in cold food ingredients decontamination. In this work aqueous solutions of carrageenan, agar e sodium alginate were gamma irradiated (0-10 kGy) in presence of ascorbic acid, roselle (Hibiscus sabdariffa L.) extract and soy isoflavone. Edible polysaccharide solutions showed to be suitable systems for the evaluation of ionizing radiation effects as they presented a singular radiosensitivity through viscosity changes. The results obtained showed that in general the antioxidants employed had a radioprotective action that can be of importance in the future commercial applications of food irradiation. (author)

  20. Radiolytically depolymerized sodium alginate improves physiological activities, yield attributes and composition of essential oil of Eucalyptus citriodora Hook.

    Science.gov (United States)

    Ali, Akbar; Khan, M Masroor A; Uddin, Moin; Naeem, M; Idrees, Mohd; Hashmi, Nadeem; Dar, Tariq Ahmad; Varshney, Lalit

    2014-11-01

    Eucalyptus citriodora Hook. is highly valued for its citronellal-rich essential oil (EO) extracted from its leaves. Hence, escalated EO production of eucalyptus is the need of hour. Marine polysaccharides (sodium alginate) are processed through gamma radiation of particular intensity, to obtain the irradiated sodium alginate (ISA). A pot experiment was conducted to study the effect of foliar application of ISA on growth, biochemical, physiological, EO yield and composition of E. citriodora. The treatments were applied as: foliar spray of deionized water only (control), seed soaked with ISA (90 mg L(-1)) and foliar spray of ISA with 30, 60, 120 and 240 mg L(-1). The treatment 6 (spray of ISA at 120 mg L(-1)) showed the highest value for most of the parameters studied. It also enhanced the EO content (33.3%), EO yield (86.7%), citronellal content (63.4%) and citronellal yield (205.5%) as compared to the control. PMID:25129727