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Sample records for alginic acid

  1. 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)

  2. 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 %.

  3. 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

  4. 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.

  5. 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

  6. 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.

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

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    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.

  8. 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

  9. 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.

  10. 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.

  11. Auger electron and X-ray photoelectron spectroscopic study of the biocorrosion of copper by alginic acid polysaccharide

    Science.gov (United States)

    Jolley, John G.; Geesey, Gill G.; Hankins, Michael R.; Wright, Randy B.; Wichlacz, Paul L.

    1989-08-01

    Thin films (3.4 nm) of copper on germanium substrates were exposed to 2% alginic acid polysaccharide aqueous solution. Pre- and post-exposure characterization were done by Auger electron spectroscopy and X-ray photoelectron spectroscopy. Ancillary graphite furnace atomic absorption spectroscopy was used to monitor the removal process of the copper thin film from the germanium substrate. Results indicate that some of the copper was oxidized by the alginic acid solution. Some of the copper was removed from the Cu/Ge interface and incorporated into the polymer matrix. Thus, biocorrosion of copper was exhibited by the alginic acid polysaccharide.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Prevention of Polyglycolic Acid-Induced Peritoneal Adhesions Using Alginate in a Rat Model

    Directory of Open Access Journals (Sweden)

    Mari Matoba

    2015-01-01

    Full Text Available Postoperative intra-abdominal or intrathoracic adhesions sometimes cause significant morbidity. We have designed three types of alginate-based treatments using strongly cross-linked (SL, weakly cross-linked (WL, and non-cross-linked (NL alginate with calcium gluconate. In rat experiments, we compared the antiadhesive effects of the three types of alginate-based treatments, fibrin glue treatment (a standard treatment, and no treatment against adhesions caused by polyglycolic acid (PGA mesh (PGA-induced adhesions. The antiadhesive materials were set on the PGA sheet fixed on the parietal peritoneum of the abdomen. Fifty-six days later, the adhesions were evaluated macroscopically by the adhesion scores and microscopically by hematoxylin-eosin staining and immunostaining. We also tested the fibroblast growth on the surface of the antiadhesive materials in vitro. The antiadhesive effects of WL and NL were superior to the no treatment and fibrin glue treatment. A microscopic evaluation confirmed that the PGA sheet was covered by a peritoneal layer constructed of well-differentiated mesothelial cells, and the inflammation was most improved in the NL and WL. The fibroblast growth was inhibited most on the surfaces of the NL and WL. These results suggest that either the WL or NL treatments are suitable for preventing PGA-induced adhesions compared to SL or the conventional treatment.

  17. Drug release behavior of poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA) prepared by direct polycondensation.

    Science.gov (United States)

    Shi, Gang; Ding, Yuanyuan; Zhang, Xin; Wu, Luyan; He, Fei; Ni, Caihua

    2015-01-01

    Hydrophobically modified sodium alginate, poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA), was successfully synthesized through direct one-step polymerization of sodium alginate, glycolic acid, and lactic acid. ALG-g-PLGA self-assembled to colloidal nanoparticles and subsequently hydrogel microspheres were obtained by crosslinking ALG-g-PLGA nanoparticles in the solution of calcium chloride. The modified hydrogel microspheres could be used as the drug delivery vehicles for a hydrophobic ibuprofen. Compared with sodium alginate, ALG-g-PLGA demonstrated an improved drug loading rate, encapsulation efficiency, and prolonged release speed. The products, as novel and highly promising biomaterials, have potential applications.

  18. 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

  19. 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...

  20. Outcomes in patients with nonerosive reflux disease treated with a proton pump inhibitor and alginic acid ± glycyrrhetinic acid and anthocyanosides

    Science.gov (United States)

    Di Pierro, Francesco; Gatti, Mario; Rapacioli, Giuliana; Ivaldi, Leandro

    2013-01-01

    Background The purpose of this study was to compare the efficacy of alginic acid alone versus alginic acid combined with low doses of pure glycyrrhetinic acid and bilberry anthocyanosides as an addon to conventional proton pump inhibitor therapy in relieving symptoms associated with nonerosive reflux disease. Methods This prospective, randomized, 8-week, open-label trial was conducted at two centers. Sixty-three patients with persistent symptoms of gastroesophageal reflux disease and normal upper gastrointestinal endoscopy were eligible for the study. Patients in group A (n = 31) were treated with pantoprazole and a formula (Mirgeal®) containing alginic acid and low doses of pure glycyrrhetinic acid + standardized Vaccinium myrtillus extract for 4 weeks, then crossed over to the multi-ingredient formula for a further 4 weeks. Patients in group B (n = 32) were treated pantoprazole and alginic acid alone twice daily, then crossed over to alginic acid twice daily for a further 4 weeks. Efficacy was assessed by medical evaluation of a symptom relief score, estimated using a visual analog scale (0–10). Side effects, tolerability, and compliance were also assessed. Results Of the 63 patients enrolled in the study, 58 (29 in group A and 29 in group B) completed the 8-week trial. The baseline characteristics were comparable between the two groups. During the study, significant differences were recorded in symptom scores for both groups. In group A, symptoms of chest pain, heartburn, and abdominal swelling were less serious than in group B. Treatment A was better tolerated, did not induce hypertension, and had fewer side effects than treatment B. No significant differences in compliance were found between the two groups. Conclusion Use of low doses of pure glycyrrhetinic acid + bilberry anthocyanosides, together with alginic acid as addon therapy, substantially improves symptoms in patients with nonerosive reflux disease without increasing side effects or worsening

  1. Lysophosphatidic acid inhibition of the accumulation of Pseudomonas aeruginosa PAO1 alginate, pyoverdin, elastase and LasA

    DEFF Research Database (Denmark)

    Laux, D.C.; Corson, J.M.; Givskov, Michael Christian;

    2002-01-01

    The pathogenesis of Pseudomonas aeruginosa is at least partially attributable to its ability to synthesize and secrete the siderophore pyoverdin and the two zinc metal loproteases elastase and LasA, and its ability to form biofilms in which bacterial cells are embedded in an alginate matrix....... In the present study, a lysophospholipid, 1-paimitoyl-2-hydroxy-sn-glycero-3-phosphate [also called monopalmitoylphosphatidic acid (MPPA)], which accumulates in inflammatory exudates, was shown to inhibit the extracellular accumulation of P. aeruginosa PAO1 alginate, elastase, LasA protease and the siderophore...

  2. 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...

  3. Outcomes in patients with nonerosive reflux disease treated with a proton pump inhibitor and alginic acid ± glycyrrhetinic acid and anthocyanosides

    Directory of Open Access Journals (Sweden)

    Di Pierro F

    2013-03-01

    Full Text Available Francesco Di Pierro,1 Mario Gatti,2 Giuliana Rapacioli,3 Leandro Ivaldi4 1Velleja Research, Milan, 2Gastroenterology Department, Giussano Hospital, Monza-Brianza, 3AIOR, Piacenza, 4Digestive Endoscopic Department, Ceva Hospital, Ceva, Cuneo, Italy Background: The purpose of this study was to compare the efficacy of alginic acid alone versus alginic acid combined with low doses of pure glycyrrhetinic acid and bilberry anthocyanosides as an addon to conventional proton pump inhibitor therapy in relieving symptoms associated with nonerosive reflux disease. Methods: This prospective, randomized, 8-week, open-label trial was conducted at two centers. Sixty-three patients with persistent symptoms of gastroesophageal reflux disease and normal upper gastrointestinal endoscopy were eligible for the study. Patients in group A (n = 31 were treated with pantoprazole and a formula (Mirgeal® containing alginic acid and low doses of pure glycyrrhetinic acid + standardized Vaccinium myrtillus extract for 4 weeks, then crossed over to the multi-ingredient formula for a further 4 weeks. Patients in group B (n = 32 were treated pantoprazole and alginic acid alone twice daily, then crossed over to alginic acid twice daily for a further 4 weeks. Efficacy was assessed by medical evaluation of a symptom relief score, estimated using a visual analog scale (0–10. Side effects, tolerability, and compliance were also assessed. Results: Of the 63 patients enrolled in the study, 58 (29 in group A and 29 in group B completed the 8-week trial. The baseline characteristics were comparable between the two groups. During the study, significant differences were recorded in symptom scores for both groups. In group A, symptoms of chest pain, heartburn, and abdominal swelling were less serious than in group B. Treatment A was better tolerated, did not induce hypertension, and had fewer side effects than treatment B. No significant differences in compliance were found between the

  4. Preparation and Characterization of Alginate-Hyaluronic Acid-chitosan based Composite Gel Beads

    Institute of Scientific and Technical Information of China (English)

    HU Yan; ZHENG Mengzhu; DONG Xiaoying; ZHAO Dan; CHENG Han; XIAO Xincai

    2015-01-01

    The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid (HA) and Chitosan (CS) were successfully admixed with Ca2+/alginate (SA) gel system to produce SA/HA/CS gel beads by dual crosslinking:the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA (2%, m/v) to HA (2%, m/v) was kept at 2:1, then the mixture was dripped into the Ca2+solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2%low molecular weight CS (LMW-CS) for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMW-CS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca2+system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.

  5. Effect of alginic acid decomposing bacterium on the growth of Laminaria japonica (Phaeophyceae)

    Institute of Scientific and Technical Information of China (English)

    WANG You; TANG Xue-xi; YANG Zhen; YU Zhi-ming

    2006-01-01

    We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1)The blades of L.japonica exhibited symptoms of lesion,bleaching and deterioration when infected by the bacterium,and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species (ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde (MDA) and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase (SOD) and catalase (CAT) increased greatly when infected by the bacterium, but glutathione peroxidase (Gpx) and ascorbate peroxidase (APX) did not exhibit active responses to the bacterium throughout the experiment. (3) The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L.japonica.

  6. The Effect of Chondroitin Sulphate and Hyaluronic Acid on Chondrocytes Cultured within a Fibrin-Alginate Hydrogel

    Directory of Open Access Journals (Sweden)

    Christopher J. Little

    2014-09-01

    Full Text Available Osteoarthritis is a painful degenerative joint disease that could be better managed if tissue engineers can develop methods to create long-term engineered articular cartilage tissue substitutes. Many of the tissue engineered cartilage constructs currently available lack the chemical stimuli and cell-friendly environment that promote the matrix accumulation and cell proliferation needed for use in joint cartilage repair. The goal of this research was to test the efficacy of using a fibrin-alginate hydrogel containing hyaluronic acid (HA and/or chondroitin sulphate (CS supplements for chondrocyte culture. Neonatal porcine chondrocytes cultured in fibrin-alginate hydrogels retained their phenotype better than chondrocytes cultured in monolayer, as evidenced by analysis of their relative expression of type II versus type I collagen mRNA transcripts. HA or CS supplementation of the hydrogels increased matrix glycosaminoglycan (GAG production during the first week of culture. However, the effects of these supplements on matrix accumulation were not additive and were no longer observed after two weeks of culture. Supplementation of the hydrogels with CS or a combination of both CS and HA increased the chondrocyte cell population after two weeks of culture. Statistical analysis indicated that the HA and CS treatment effects on chondrocyte numbers may be additive. This research suggests that supplementation with CS and/or HA has positive effects on cartilage matrix production and chondrocyte proliferation in three-dimensional (3D fibrin-alginate hydrogels.

  7. Hyaluronic acid and alginate covalent nanogels by template cross-linking in polyion complex micelle nanoreactors.

    Science.gov (United States)

    De Santis, Serena; Diociaiuti, Marco; Cametti, Cesare; Masci, Giancarlo

    2014-01-30

    Hyaluronic acid (HA) and alginate (AL) covalent nanogels cross-linked with l-lysine ethyl ester were prepared by template chemical cross-linking of the polysaccharide in polyion complex micelle (PIC) nanoreactors. By using this method we were able to prepare HA and AL nanogels without organic solvents. PICs were prepared by using poly(ethylene oxide)-block-poly[(3-acrylamidopropyl)-trimethylammonium chloride] (PEO-b-PAMPTMA) or poly[(N-isopropylacrylamide)-block-PAMPTMA] (PNIPAAM-b-PAMPTMA). Only PNIPAAM-b-PAMPTMA block copolymers allowed to prepare PIC with small and controlled size. Short polysaccharide chains (Xn=50 and 63 for AL and HA, respectively, where Xn is the number of monosaccharidic units present in the polysaccharide) where used to optimize PIC formation. The remarkable difference in charge density and rigidity of HA and AL did not have a significant influence on the formation of PICs. PICs with small size (diameter of about 50-80 nm) and low polydispersity were obtained up to 5mg/mL of polymer. After cross-linking with l-lysine ethyl ester, the nanoreactors were dissociated by adding NaCl. The nanogels were easily purified and isolated by dialysis. The dissociation of the nanoreactors and the formation of the nanogels were confirmed by (1)H NMR, DLS, TEM and ζ-potential measurements. The size of the smallest nanogels in solution in the swollen state was 50-70 nm in presence of salt and 80-100 nm in water. PMID:24299754

  8. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. PMID:26672465

  9. Olfaction Presentation System Using Odor Scanner and Odor-Emitting Apparatus Coupled with Chemical Capsules of Alginic Acid Polymer

    Science.gov (United States)

    Sakairi, Minoru; Nishimura, Ayako; Suzuki, Daisuke

    For the purpose of the application of odor to information technology, we have developed an odor-emitting apparatus coupled with chemical capsules made of alginic acid polymer. This apparatus consists of a chemical capsule cartridge including chemical capsules of odor ingredients, valves to control odor emission, and a temperature control unit. Different odors can be easily emitted by using the apparatus. We have developed an integrated system of vision, audio and olfactory information in which odor strength can be controlled coinciding with on-screen moving images based on analytical results from the odor scanner.

  10. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber.

    Science.gov (United States)

    Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1day seeded. Cell-cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  11. Encapsulation of α-lipoic acid intochitosan and alginate/gelatin hydrogel microparticles and its in vitro antioxidant activity

    Directory of Open Access Journals (Sweden)

    Vidović Bojana B.

    2016-01-01

    Full Text Available Alpha-lipoic acidis an organosulphur compound well-known for its therapeutic potential and antioxidant properties. However, the effective use of α-lipoic acid depends on biological plasma half-life and its preserving stability, which could be improved by encapsulation. In this study, α-lipoic acid was incorporated into chitosan microparticles obtained by reverse emulsion crosslinking technique, as well as into microparticles of alginate/gelatin crosslinked with zinc ions. Encapsulation of α-lipoic acid in both cases was carried out by swelling of synthesized dried microparticles by their dipping in a solution of the active substance under strictly controlled conditions. Encapsulation efficiency of α-lipoic acid obtained in this study was up to 53.9 %. The structural interaction of α-lipoic acid with the carriers was revealed by Fourier transform infrared spectroscopy. In vitro released studies showed that controlled release of α-lipoic acid was achieved through its encapsulation into chitosan microparticles. The results of in vitro antioxidative activity assays of released α-lipoic acid indicated that antioxidant activity was preserved at a satisfactory level. These obtained results suggested that chitosan microparticles could be suitable for modeling the controlled release of α-lipoic acid. [Projekat Ministartsva nauke Republike Srbije, br. III 46010 i br. III46001

  12. Designing improved poly lactic-co-glycolic acid microspheres for a malarial vaccine: incorporation of alginate and polyinosinic-polycytidilic acid.

    Science.gov (United States)

    Salvador, Aiala; Igartua, Manoli; Hernández, Rosa María; Pedraz, José Luis

    2014-01-01

    Vaccination using proteins and peptides is currently gaining importance. One of the major drawbacks of this approach is the lack of an efficient immune response when the antigens are administered without adjuvants. In this study, we have taken the advantage of a combined adjuvant system in order to improve the immunogenicity of the SPf66 malarial antigen. For that purpose, we have combined poly (lactic-co-glycolic) acid microspheres, alginate, and polyinosinic polycytidilic acid. Our results show that microspheres can enhance the IgG production obtained with Freund's complete adjuvant. We have attributed this improvement to the presence of polyinosinic polycytidilic acid, since formulations comprising this adjuvant overcame the immune response from the others. In addition, our microspheres produced both IgG1 and IgG2a, leading to mixed Th1/Th2 activation, optimal for malaria vaccination. In conclusion, we have designed a preliminary formulation with a high potential for the treatment of malaria.

  13. Fabrication of a novel bone ash-reinforced gelatin/alginate/hyaluronic acid composite film for controlled drug delivery.

    Science.gov (United States)

    Alemdar, Neslihan

    2016-10-20

    In this study, a novel pH-sensitive composite film with enhanced thermal and mechanical properties was prepared by the incorporation of bone ash at varying concentrations from 0 to 10v.% into gelatin/sodium alginate/hyaluronic acid (Gel/SA/HyA) polymeric structure for colon-specific drug delivery system. Films were characterized by FT-IR, SEM, and XRD analyses. Thermal and mechanical performances of films were determined by DSC, TGA and universal mechanical tester, respectively. Results proved that thermal stability and mechanical properties of bone ash-reinforced composite films improved significantly with respect to that of neat Gel/SA/HyA film. Cytotoxicity assay for composite films was carried out by using L929 cells. Water uptake capacity of films was determined by swelling test. Herein, release experiments of 5-Fluorouracil (5-FU) were performed in two different solutions (pH 2.1 and 7.4). The results assured that Gel/SA/HyA film containing BA could be considered as a potential biomaterial for controlled drug delivery systems. PMID:27474650

  14. 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

  15. 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.

  16. Oxidation of alginate and pectate biopolymers by cerium(IV) in perchloric and sulfuric acid solutions: A comparative kinetic and mechanistic study.

    Science.gov (United States)

    Fawzy, Ahmed

    2016-03-15

    The kinetics of oxidation of alginate (Alg) and pectate (Pec) carbohydrate biopolymers was studied by spectrophotometry in aqueous perchloric and sulfuric acid solutions at fixed ionic strengths and temperature. In both acids, the reactions showed a first order dependence on [Ce(IV)], whereas the orders with respect to biopolymer concentrations are less than unity. In perchloric acid, the reactions exhibited less than unit orders with respect to [H(+)] whereas those proceeded in sulfuric acid showed negative fractional-first order dependences on [H(+)]. The effect of ionic strength and dielectric constant was studied. Probable mechanistic schemes for oxidation reactions were proposed. In both acids, the final oxidation products were characterized as mono-keto derivatives of both biopolymers. The activation parameters with respect to the slow step of the mechanisms were computed and discussed. The rate laws were derived and the reaction constants involved in the different steps of the mechanisms were calculated.

  17. Mechanical properties of C-5 epimerized alginates.

    Science.gov (United States)

    Mørch, Y A; Holtan, S; Donati, I; Strand, B L; Skjåk-Braek, G

    2008-09-01

    There is an increased need for alginate materials with both enhanced and controllable mechanical properties in the fields of food, pharmaceutical and specialty applications. In the present work, well-characterized algal polymers and mannuronan were enzymatically modified using C-5 epimerases converting mannuronic acid residues to guluronic acid in the polymer chain. Composition and sequential structure of controls and epimerized alginates were analyzed by (1)H NMR spectroscopy. Mechanical properties of Ca-alginate gels were further examined giving Young's modulus, syneresis, rupture strength, and elasticity of the gels. Both mechanical strength and elasticity of hydrogels could be improved and manipulated by epimerization. In particular, alternating sequences were found to play an important role for the final mechanical properties of alginate gels, and interestingly, a pure polyalternating sample resulted in gels with extremely high syneresis and rupture strength. In conclusion, enzymatic modification was shown to be a valuable tool in modifying the mechanical properties of alginates in a highly specific manner.

  18. Effects of molecular weight and ratio of guluronic acid to mannuronic acid on the antioxidant properties of sodium alginate fractions prepared by radiation-induced degradation

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Murat, E-mail: msen@hacettepe.edu.t [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, Beytepe, 06800 Ankara (Turkey)

    2011-01-15

    In this study, the effects of the molecular weight and ratio of guluronic acid (G) to mannuronic acid (M), G/M, of some sodium alginate (NaAlg) fractions on their antioxidative properties were investigated. Low-molecular-weight-fractions with various G/M were prepared by gamma radiation-induced degradation of NaAlg. Change in their molecular weight was monitored. 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{sup {center_dot}}). 50% inhibition concentrations of the 50 kGy-irradiated NaAlgs having molecular weights of 20.5, 17.7, and 16.0 kDa were found to be 11.0, 18.0, and 24.0 mg/ml, respectively, whereas the fractions of the same molecular weight with a lower G/M exhibited a better DPPH{sup {center_dot}}scavenging activity. The results demonstrated that its molecular weight and G/M were important factors in controlling the antioxidant properties of NaAlg.

  19. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    Science.gov (United States)

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  20. Preparation and Properties of Cellutose-Alginic Acid Interpolymeric Complex Films

    Institute of Scientific and Technical Information of China (English)

    Xian-Hua HE; Mei-Yu HUANG; Ying-Yan JIANG

    2005-01-01

    @@ 1Introduction General synthetic polymers such as polyethylene, polyvinyl chloride, polystyrene etc. have been produced and used in large quantities. They are very cheap, but their wastes are difficult to decompose in nature so to cause environmental pollution . In order to overcome such disadvantage, various kinds of biodegradable synthetic polymers such as polyactic acid, aliphatic polyester, polyvinyl alcohol complexes etc. have been researched[1]. However, they are expensive, so cannot be manufactured on large scale. Biopolymers such as starch and cellulose have been used as raw materials to prepare biodegradable polymer materials[1,2]. Starch derivatives and starch containing materials have been prepared to obtain relatively cheap biodegradable polymer materials, but their water proofness is not so good[2].

  1. 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.

  2. Production Technology of Water Soluble Fertilizer Containing Alginic Acid%含海藻酸水溶肥生产技术

    Institute of Scientific and Technical Information of China (English)

    张从军; 曹广峰

    2015-01-01

    The crude phosphoric acid from wet process phosphoric acid production is treated by chelation,then the formed monoammonium phosphate solution is added to mixer according to measurement formula with urea,potassium chloride,magnesium sulfate solution and humic acid solution to mix and blend,finally it is measured and packed up,the macroelement water soluble fertilizer containing alginic acid extract,i.e.,water soluble fertilizer containing alginic acid,is obtained.This water soluble fertilizer can be used by spraying,drip and irrigation in facility agriculture,attaining the aim of water saving,fertilizer saving and labor saving.%对湿法磷酸生产中的粗磷酸进行螯合处理,然后将形成的磷酸一铵溶液与尿素、氯化钾、硫酸镁溶液以及腐殖酸溶液按配方计量后加入混合机中混合搅拌,再进行计量、包装得到含海藻酸提取物的大量元素全水溶性液体肥料,即含海藻酸水溶肥。该水溶肥可应用于喷滴灌等设施农业,实现水肥一体化,同时达到节水、节肥、省工的目的。

  3. Solubilizing carbon nanotubes through noncovalent functionalization. Insight from the reversible wrapping of alginic acid around a single-walled carbon nanotube.

    Science.gov (United States)

    Liu, Yingzhe; Chipot, Christophe; Shao, Xueguang; Cai, Wensheng

    2010-05-01

    Carbon nanotubes coated with alginic acid (AA) through noncovalent functionalization have been shown to be soluble and dispersed in water. In the present contribution, all-atom molecular dynamics simulations have been performed to probe the self-assembly mechanism that underlies the formation of complexes by AA and a single-walled carbon nanotube (SWCNT), both in the gas phase and in an aqueous solution. Results of these simulations reveal that AA can wrap around SWCNT by virtue of van der Waals attractions and organize into a compact helical structure, a process induced in the gas phase by hydrogen-bonding interactions. In contrast, in an alginate aqueous solution, a loose helical wrapping mode is found to be favored by virtue of electrostatic repulsions in conjunction with the weakening of hydrogen-bonding interactions. Documented experimentally (Liu, Y.; et al. Small 2006, 2, 874-878) and coined "Great Wall of China" motif, the typical arrangement of AA residues around the tubular structure, conducive to dissolve nanotubes, is observed in the present simulations. Investigation of metal cations binding to AA suggests that calcium ions can mediate aggregation of AA chains by interacting strongly with the carboxylate groups, thereby leading to reverse unwrapping. The results reported in this work shed meaningful light on the potential of noncovalent functionalization for solubilizing carbon nanotubes, and open exciting perspectives for the design of new wrapping agents that are envisioned to form the basis of innovative nanomaterials targeted at chemical and biomedical applications.

  4. The study of non-linear kinetics and adsorption isotherm models for Acid Red 18 from aqueous solutions by magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate.

    Science.gov (United States)

    Berizi, Zohre; Hashemi, Seyed Yaser; Hadi, Mahdi; Azari, Ali; Mahvi, Amir Hosein

    2016-01-01

    Azo dyes are widely used in various industries. These substances produce toxic byproducts in aquatic environments in addition to their mutagenic and carcinogenic potential effects. In this study, the effect of magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate in batch systems and nonlinear kinetic and adsorption isotherm models were investigated. Magnetite nanoparticles were synthesized by chemical co-precipitation method and then modified and used as adsorbent to adsorb Acid Red 18. After determining the optimum pH and adsorbent dose, non-equilibrium models for kinetic adsorption were tested with concentrations (25-100 mg/L) and at eight different periods of time (1-15 min) and the pseudo-first-order and pseudo-second-order non-linear models were used to describe the results. For adsorption isotherm, a contact time of 120 min was studied in different concentrations (25-100 mg/L) and the residual concentration of Acid Red 18 was obtained. The results are described by non-linear Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The optimum amounts of pH for magnetite nanoparticles and for modified ones were 3 and 5, respectively, the efficiencies were 0.75 and 0.2 g/L, respectively. According to the results sodium alginate has a high performance in adsorption of Acid Red 18. Adjusted correlation coefficients and chi-square test showed that Freundlich isotherm and then Langmuir isotherm can well describe the experimental results. In Freundlich, the value of (Kf) was 3.231 (L/g) for magnetite nanoparticles and 21.615 (L/g) for modified adsorbent. In Langmuir, the value of (qm) was 16.259 (mg/g) for magnetite nanoparticles and 73.464 (mg/g) for modified adsorbent. Comparing the Langmuir maximum calculated adsorption capacity indicated that modified adsorbent can adsorb the pollutants 6.5 times more than the other one.

  5. The effects of olive oil emulsified alginate on the physico-chemical, sensory, microbial, and fatty acid profiles of low-salt, inulin-enriched sausages.

    Science.gov (United States)

    Beriain, M J; Gómez, I; Petri, E; Insausti, K; Sarriés, M V

    2011-05-01

    This paper examines variations in the quality of low-salt, inulin enriched Pamplona-style chorizo, in which some of the pork back fat was replaced with olive oil. Four different sausage formulations were prepared in which 50% of the pork back fat was replaced with olive oil emulsified with alginate and 58% of the sodium chloride was replaced with 20% potassium chloride and 38% calcium chloride. Four lots were prepared, three with 3%, 6% and 10% proportions of added inulin were labeled O-I 3%, O-I 6% and O-I 10%, respectively; while one, lot O, was without inulin. These four formulations were compared with a control manufactured according to the traditional formula using pork back fat. The various lots were tested for proximate analysis, pH, processing loss, water activity, lactic acid bacteria, Salmonella and Listeria monocytogenes, physico-chemical composition, instrumental colour (CIE L*a*b*), texture profile and fatty acid composition during mixing and at days 3, 10, 17, 24 and 31 of the drying process. A sensory evaluation was also performed by a seven-member trained panel, to obtain a descriptive analysis of the taste, texture and appearance of the product. The addition of olive oil alginate emulsion and inulin, O-I 6%, resulted in a low-salt, reduced-fat product (20% less fat than traditional sausage), richer in monounsaturated fatty acids (10%), while retaining sensory notes similar to those of the traditional chorizo used as a control and achieved a good acceptability rating.

  6. The study of non-linear kinetics and adsorption isotherm models for Acid Red 18 from aqueous solutions by magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate.

    Science.gov (United States)

    Berizi, Zohre; Hashemi, Seyed Yaser; Hadi, Mahdi; Azari, Ali; Mahvi, Amir Hosein

    2016-01-01

    Azo dyes are widely used in various industries. These substances produce toxic byproducts in aquatic environments in addition to their mutagenic and carcinogenic potential effects. In this study, the effect of magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate in batch systems and nonlinear kinetic and adsorption isotherm models were investigated. Magnetite nanoparticles were synthesized by chemical co-precipitation method and then modified and used as adsorbent to adsorb Acid Red 18. After determining the optimum pH and adsorbent dose, non-equilibrium models for kinetic adsorption were tested with concentrations (25-100 mg/L) and at eight different periods of time (1-15 min) and the pseudo-first-order and pseudo-second-order non-linear models were used to describe the results. For adsorption isotherm, a contact time of 120 min was studied in different concentrations (25-100 mg/L) and the residual concentration of Acid Red 18 was obtained. The results are described by non-linear Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The optimum amounts of pH for magnetite nanoparticles and for modified ones were 3 and 5, respectively, the efficiencies were 0.75 and 0.2 g/L, respectively. According to the results sodium alginate has a high performance in adsorption of Acid Red 18. Adjusted correlation coefficients and chi-square test showed that Freundlich isotherm and then Langmuir isotherm can well describe the experimental results. In Freundlich, the value of (Kf) was 3.231 (L/g) for magnetite nanoparticles and 21.615 (L/g) for modified adsorbent. In Langmuir, the value of (qm) was 16.259 (mg/g) for magnetite nanoparticles and 73.464 (mg/g) for modified adsorbent. Comparing the Langmuir maximum calculated adsorption capacity indicated that modified adsorbent can adsorb the pollutants 6.5 times more than the other one. PMID:27642843

  7. Engineered yeast whole-cell biocatalyst for direct degradation of alginate from macroalgae and production of non-commercialized useful monosaccharide from alginate.

    Science.gov (United States)

    Takagi, Toshiyuki; Yokoi, Takahiro; Shibata, Toshiyuki; Morisaka, Hironobu; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-02-01

    Alginate is a major component of brown macroalgae. In macroalgae, an endolytic alginate lyase first degrades alginate into oligosaccharides. These oligosaccharides are further broken down into monosaccharides by an exolytic alginate lyase. In this study, genes encoding various alginate lyases derived from alginate-assimilating marine bacterium Saccharophagus degradans were isolated, and their enzymes were displayed using the yeast cell surface display system. Alg7A-, Alg7D-, and Alg18J-displaying yeasts showed endolytic alginate lyase activity. On the other hand, Alg7K-displaying yeast showed exolytic alginate lyase activity. Alg7A, Alg7D, Alg7K, and Alg18J, when displayed on yeast cell surface, demonstrated both polyguluronate lyase and polymannuronate lyase activities. Additionally, polyguluronic acid could be much easily degraded by Alg7A, Alg7K, and Alg7D than polymannuronic acid. In contrast, polymannuronic acid could be much easily degraded by Alg18J than polyguluronic acid. We further constructed yeasts co-displaying endolytic and exolytic alginate lyases. Degradation efficiency by the co-displaying yeasts were significantly higher than single alginate lyase-displaying yeasts. Alg7A/Alg7K co-displaying yeast had maximum alginate degrading activity, with production of 1.98 g/L of reducing sugars in a 60-min reaction. This system developed, along with our findings, will contribute to the efficient utilization and production of useful and non-commercialized monosaccharides from alginate by Saccharomyces cerevisiae. PMID:26490549

  8. Study on the enzymatic activity of Caspase-3 in response to alginic acid decomposing bacteria in Laminaria japonica Aresch.(Phaeophyta)

    Institute of Scientific and Technical Information of China (English)

    Wang Gaoge; Lin Wei; Yan Xiaojun; Duan Delin

    2005-01-01

    Caspase-3 is the major factor in apoptosis triggered by various stimuli, and plays a critical role during the apoptosis process. By using CaspGLOWTM fluorescein active caspase-3 staining method, caspase-3 enzymatic activities were detected in response to alginic acid bacteria in Laminaria japonica sporophytic tissues. Results showed that caspase-3 enzymatic activities were observed at 5 min after the infection. Caspase-3 enzymatic activity increased with the infection time, and had a tendency of moving from the infection site to outside. By applying caspase-specific peptide inhibitor Z-VAD-FMK, caspase-3 activation could be effectively abolished in the infected tissues. Our results indicate that programmed cell death (PCD) may be involved in the infected Laminaria japonica sporophytic tissues, and provide the evidence that defense mechanisms in algae may have similar caspase cascade events in animals.

  9. Use of alginate beads as carriers for lactic acid bacteria in a structured system and preliminary validation in a meat product.

    Science.gov (United States)

    Corbo, Maria Rosaria; Bevilacqua, Antonio; Speranza, Barbara; Di Maggio, Barbara; Gallo, Mariangela; Sinigaglia, Milena

    2016-01-01

    This paper proposes the microencapsulation into alginate beads of 4 isolates of lactic acid bacteria (Lactobacillus spp.), previously isolated from pork meat. First, the beads were studied in relation to the encapsulation yield (EY), kinetic of cell release in a structured system, and survival throughout bead storage at 4 °C. EY was 93-96% and the survival of the encapsulated microorganisms was variable, with two isolates showing a bacterial population of 6.1-6.9 log cfu/g after 35 days under refrigerated conditions. Thereafter, the paper addressed a preliminary validation in a meat model system, containing salt, nitrites and nitrates, lactose, pepper, and then in a commercial preparation of pork meat. For the validation in pork meat, free cells were used as controls. Cell released from beads were able to achieve a significant acidification; in particular, after 7 days they showed the same results of free cells. PMID:26476507

  10. Elution of nickel ions from alginate beads in an acid media; Elucion de iones de niquel desde esferas de alginato en un medio acido

    Energy Technology Data Exchange (ETDEWEB)

    Aracena, A.; Carcamo, F.; Jerez, O.; Constanzo, R.

    2016-05-01

    Elution of nickel ions from alginate beads was studied in a temperature range of 2 to 80 degree centigrade and a sulfuric acid concentration between 0.005 to 2.5 g L{sup -}1. The elution mechanism was established by ion exchange between nickel and ions protons, obtaining a value of 93% elution at a temperature of 80 degree centigrade and a H{sub 2}SO{sub 4} concentration of 0.25 g L{sup -}1. The influence of other acids on nickel elution was also studied. The nickel elution rate was significantly influenced by temperature and concentration of H{sub 2}SO{sub 4}. Elution kinetics of nickel ions was studied, and the 1-(1-α){sup 1}/3=k{sub a}ppt model properly described the kinetics of this reaction. The dependence of nickel elution on the sulfuric acid concentration was of the order of 0.33. Moreover, the intrinsic rate constants were determined and an activation energy value of 54.5 kJ mol{sup -}1 was obtained for the temperature range studied. The results indicated that the nickel elution is a process controlled by chemical reactions. (Author)

  11. Diffusion of Acetic Acid Across Oil/Water Interface in Emulsification-Internal Gelation Process for Preparation of Alginate Gel Beads

    Institute of Scientific and Technical Information of China (English)

    LIU Xiu-dong; YU Wei-ting; LIN Jun-zhang; MA Xiao-jun; YUAN Quan

    2007-01-01

    Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules. Although an alternative novel emulsification-internal gelation technology has been established and both the properties and the potential applications of the beads in drug delivery systems have been studied, the mechanism has not been well understood compared with the traditional droplet method( external gelation technology). On the basis of our previous knowledge that the novel technology is composed of complicatedly consecutive processes with multistep diffusion and re action, and the diffusion of acetic acid across oil/water interface being the prerequisite that determines the occurrence and rate for the reactions and the structures and properties of final produced gel beads, a special emphasis was placed on the diffusion process. With the aid of diffusion modeling and simple experimental design, the diffusion rate constant and diffusion coefficient of acetic acid across oil/water interface were determined to be in the orders of magnitude of 10-6 and 10-16, respectively. This knowledge will be of particular importance in understanding and interpreting the formation, structure of the gel beads and the relationship between the structure and properties and guiding the preparation and quality control of the gel beads.

  12. 聚丙烯酸-海藻酸钠吸水树脂的降解研究%Study on the Degradation of Polyacrylic Acid -Sodium Alginate Absorbent Resin

    Institute of Scientific and Technical Information of China (English)

    黄慧珍

    2012-01-01

    通过土壤掩埋法和菌类生长法研究了聚丙烯酸-海藻酸钠高吸水树脂的降解性能。实验结果表明,聚丙烯酸—海藻酸钠高吸水性树脂具有较好的生物降解性能,能够被土壤以及特定菌类降解,聚丙烯酸—海藻酸钠高吸水性树脂在土壤中埋置65天后降解率达43%,通过菌类降解,50天后降解率达60%。%Polyacrylic acid -sodium alginate superabsorbent degradation properties were studied by soil burial meth- od and fungi growth method. Experimental results showed that Polyacrylic acid -sodium alginate high absorbent resin had a good biodegradability to degradation of soil and specific fungi. Polyacrylic acid - sodium alginate superabsorbent 65 days after being embedded in the soil, the degradation rate could reach 43%. Degradation by fungi, 50 days later, the degra- dation rate could reach 60%.

  13. Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and methylene blue.

    Science.gov (United States)

    Jung, Kyung-Won; Choi, Brian Hyun; Hwang, Min-Jin; Jeong, Tae-Un; Ahn, Kyu-Hong

    2016-11-01

    Biomass-based granular activated carbon was successfully prepared by entrapping activated carbon powder derived from spent coffee grounds into calcium-alginate beads (SCG-GAC) for the removal of acid orange 7 (AO7) and methylene blue (MB) from aqueous media. The dye adsorption process is highly pH-dependent and essentially independent of ionic effects. The adsorption kinetics was satisfactorily described by the pore diffusion model, which revealed that pore diffusion was the rate-limiting step during the adsorption process. The equilibrium isotherm and isosteric heat of adsorption indicate that SCG-GAC possesses an energetically heterogeneous surface and operates via endothermic process in nature. The maximum adsorption capacities of SCG-GAC for AO7 (pH 3.0) and MB (pH 11.0) adsorption were found to be 665.9 and 986.8mg/g at 30°C, respectively. Lastly, regeneration tests further confirmed that SCG-GAC has promising potential in its reusability, showing removal efficiency of more than 80% even after seven consecutive cycles. PMID:27494099

  14. Influence of various alginate brands on the redifferentiation of dedifferentiated bovine articular chondrocytes in alginate bead culture under high and low oxygen tension.

    Science.gov (United States)

    Domm, C; Schünke, M; Steinhagen, J; Freitag, S; Kurz, B

    2004-01-01

    We examined the influence of various alginates on the redifferentiation of dedifferentiated articular chondrocytes in alginate bead culture under low (5%) and (21%) high oxygen supply. Isolated bovine articular chondrocytes were dedifferentiated and multiplied by 2-week monolayer culture under 21% oxygen. They were subcultured at a density of 10(7) cells/mL in six different commercially available sodium alginates (1.2%, w/v) and held under 21 or 5% oxygen for 3 weeks. Proliferation (DNA measurement on days 0 and 21 of culture), collagen type II production (immunocytochemistry and Western blotting), and [(3)H]proline and [(35)S]sulfate incorporation were monitored. Collagen type II production was significantly stronger under 5% oxygen compared with 21% oxygen in two alginates (three other alginates nearly reached the significance level). However, alginate-based differences proved not to be significant. [(3)H]Proline incorporation was not influenced by alginate but showed strong oxygen dependency (up to 3-fold higher under 5% oxygen). For [(35)S]sulfate incorporation oxygen dependency was even stronger (up to 8-fold higher under 5% oxygen) and significant alginate-dependent differences were found for several alginates. The effects of the different alginates did not correlate with their pH, viscosity, or guluronic:mannuronic acid ratio. Thus, the type of alginate and even more, the oxygen supply, influence the redifferentiation and matrix production of dedifferentiated bovine articular chondrocytes. PMID:15684688

  15. 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.

  16. Characterization of AlgMsp, an alginate lyase from Microbulbifer sp. 6532A.

    Directory of Open Access Journals (Sweden)

    Steven M Swift

    Full Text Available Alginate is a polysaccharide produced by certain seaweeds and bacteria that consists of mannuronic acid and guluronic acid residues. Seaweed alginate is used in food and industrial chemical processes, while the biosynthesis of bacterial alginate is associated with pathogenic Pseudomonas aeruginosa. Alginate lyases cleave this polysaccharide into short oligo-uronates and thus have the potential to be utilized for both industrial and medicinal applications. An alginate lyase gene, algMsp, from Microbulbifer sp. 6532A, was synthesized as an E.coli codon-optimized clone. The resulting 37 kDa recombinant protein, AlgMsp, was expressed, purified and characterized. The alginate lyase displayed highest activity at pH 8 and 0.2 M NaCl. Activity of the alginate lyase was greatest at 50°C; however the enzyme was not stable over time when incubated at 50°C. The alginate lyase was still highly active at 25°C and displayed little or no loss of activity after 24 hours at 25°C. The activity of AlgMsp was not dependent on the presence of divalent cations. Comparing activity of the lyase against polymannuronic acid and polyguluronic acid substrates showed a higher turnover rate for polymannuronic acid. However, AlgMSP exhibited greater catalytic efficiency with the polyguluronic acid substrate. Prolonged AlgMsp-mediated degradation of alginate produced dimer, trimer, tetramer, and pentamer oligo-uronates.

  17. 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.

  18. 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

  19. 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...

  20. Prospective, randomized, and active controlled study of the efficacy of alginic acid and antacid in the treatment of patients with endoscopy-negative reflux disease

    Institute of Scientific and Technical Information of China (English)

    I-Rue Lai; Ming-Shiang Wu; Jaw-Town Lin

    2006-01-01

    AIM: To assess the efficacy and safety of a compound containing alginic acid plus antacid (Topaal ) compared to equal-strength antacid (Nacid ) in patients with endoscopy-negative reflux disease (ENRD).METHODS: A total of 121 patients with ENRD were randomized to receive Topaal (65 patients) or Nacid (56patients) for 6 weeks, with a consultation every 3 weeks.The primary end-point assessment was the change in the severity of heartburn as evaluated using a visual analog scale (VAS) at 6 weeks. The secondary end-point assessments were the VAS at 3 weeks, the change of frequency of the reflux symptom, the change of quality of life and the adverse effects.RESULTS: Demographics of randomized subjects in each treatment group were comparable except that the Topaal group included more males. The baseline characteristics between the groups were similar. After 6weeks of treatment, the reduction of VAS of heartburn was more prominent in the Topaal group (-6.29 cm vs -4.11 cm). At the 3rd week, Topaal group showed greater reduction of VAS for heartburn (P=0.0016),regurgitation (P= 0.0006), vomiting (P= 0.0373), and belching (P<0.0001). The patients of the Topaal group had lower frequency of heartburn (P= 0.0015) and pain (P= 0.0163) at the end of the 6-week treatment period.From the doctor's point of view, the Topaal group also showed significant reduction in the severity of heartburn (P=0.0020), regurgitation (P=0.0081), vomiting (P= 0.0182), and belching (P= 0.0018) at the end of the treatment. The improvement of the quality of life was more remarkable in the Topaal group at the end of the 6-week treatment period (P< 0.0001). For the adverse effect, there was no difference in both the groups.CONCLUSION: Topaal is more effective than Nacid for the treatment of symptoms presented by patients with ENRD.

  1. 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

  2. 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...

  3. 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

  4. Putative Alginate Assimilation Process of the Marine Bacterium Saccharophagus degradans 2-40 Based on Quantitative Proteomic Analysis.

    Science.gov (United States)

    Takagi, Toshiyuki; Morisaka, Hironobu; Aburaya, Shunsuke; Tatsukami, Yohei; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-02-01

    Quantitative proteomic analysis was conducted to assess the assimilation processes of Saccharophagus degradans cultured with glucose, pectin, and alginate as carbon sources. A liquid chromatography-tandem mass spectrometry approach was used, employing our unique, long monolithic silica capillary column. In an attempt to select candidate proteins that correlated to alginate assimilation, the production of 23 alginate-specific proteins was identified by statistical analyses of the quantitative proteomic data. Based on the analysis, we propose that S. degradans has an alginate-specific gene cluster for efficient alginate utilization. The alginate-specific proteins of S. degradans were comprised of alginate lyases, enzymes related to carbohydrate metabolism, membrane transporters, and transcription factors. Among them, the short-chain dehydrogenase/reductase Sde_3281 annotated in the alginate-specific cluster showed 4-deoxy-L-erythro-5-hexoseulose uronic acid reductase (DehR) activity. Furthermore, we found two different genes (Sde_3280 and Sde_0939) encoding 2-keto-3-deoxy-D-gluconic acid (KDG) kinases (KdgK) that metabolize the KDG derived from alginate and pectin in S. degradans. S. degradans used Sde_3280 to phosphorylate the KDG derived from alginate and Sde_0939 to phosphorylate the KDG derived from pectin. The distinct selection of KdgKs provides an important clue toward the elucidation of how S. degradans recognizes and processes polysaccharides.

  5. 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.

  6. Optimization of Culturing Condition and Medium Composition for the Production of Alginate Lyase by a Marine Vibrio sp. YKW-34

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    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℃. 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.

  7. 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.

  8. 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...

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. Preparation and Characterization of Azadirachtin Alginate-Biosorbent Based Formulations: Water Release Kinetics and Photodegradation Study.

    Science.gov (United States)

    Flores-Céspedes, Francisco; Martínez-Domínguez, Gerardo P; Villafranca-Sánchez, Matilde; Fernández-Pérez, Manuel

    2015-09-30

    The botanical insecticide azadirachtin was incorporated in alginate-based granules to obtain controlled release formulations (CRFs). The basic formulation [sodium alginate (1.47%) - azadirachtin (0.28%) - water] was modified by the addition of biosorbents, obtaining homogeneous hybrid hydrogels with high azadirachtin entrapment efficiency. The effect on azadirachtin release rate caused by the incorporation of biosorbents such as lignin, humic acid, and olive pomace in alginate formulation was studied by immersion of the granules in water under static conditions. The addition of the biosorbents to the basic alginate formulation reduces the rate of release because the lignin-based formulation produces a slower release. Photodegradation experiments showed the potential of the prepared formulations in protecting azadirachtin against simulated sunlight, thus improving its stability. The results showed that formulation prepared with lignin provided extended protection. Therefore, this study provides a new procedure to encapsulate the botanical insecticide azadirachtin, improving its delivery and photostability. PMID:26345112

  17. Immobilization of alginate-PAC on Sepabeads EC-HA support

    Directory of Open Access Journals (Sweden)

    Žuža Milena G.

    2011-01-01

    Full Text Available Penicillin acylase (PAC is an important industrial enzyme for the production of many β-lactam antibiotics. It is capable of catalyzing the hydrolysis of penicillin G (Pen G to generate phenylacetic acid (PAA and 6-aminopenicillanic acid (6-APA. In this paper, in order to prevent enzyme inactivation, an attempt of coupling enzyme modification and immobilization was presented. Chemical modification was promoted to introduce carbohydrate moiety into the PAC molecule, capable of being covalently linked to an amino support. This seems to provide a possibility to couple the enzyme without risking a reaction at the active site which might cause a loss of activity. PAC molecules were modified by cross-linking with polyaldehyde derivatives of alginate in order to add them new and useful functions. Immobilization of alginate-PAC on Sepabeads EC-HA was used as a model system in order to demonstrate the potential of this strategy. Optimal conditions for covalent immobilization of alginate-PAC from Escherichia coli on support Sepabeads EC-HA, were investigated. The immobilized enzyme was then characterized by evaluating the potential effects of immobilization on its thermal stability, temperature and pH profile in comparison with native non-modified PAC and modified non-immobilized PAC. The maximum amount of the alginate-PAC coupled on the dry support of 99 mg/g was satisfactory. Deactivation rate constants at 50 ºC for free PAC, alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA were 2,32; 50,65 and 1,68 h-1, respectively. Alginate-PAC and alginate-PAC immobilized on Sepabeads EC-HA had the same pH and temperature optimum as the native non-modified PAC.

  18. 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

  19. 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.

  20. 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.

  1. 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)

  2. 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)

  3. 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

  4. Cytotoxicity of liver targeted drug-loaded alginate nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this study, novel liver targeted doxorubicin (DOX) loaded alginate (ALG) nanoparticles were prepared by CaCl2 crosslinking method. Glycyrrhetinic acid (GA, a liver targeted molecule) modified alginate (GA-ALG) was synthesized in a heterogeneous system, and the structure of GA-ALG and the substitu-tion degree of GA were analyzed by 1H NMR, FT-IR and elemental analysis. The drug release profile under the simulated physiological condition and cytotoxicity experiments of drug-loaded GA-ALG nanoparticles were carried out in vitro. Transmission electron micrographs (TEM) and dynamic light scattering (DLS) analysis showed that drug-loaded GA-ALG nanoparticles have spherical shape structure with the mean hydrodynamic diameter around 214 ± 11 nm. The drug release was shown to last 20 days, and the MTT assay suggested that drug-loaded GA-ALG nanoparticles had a distinct kill-ing effect on 7703 hepatocellular carcinoma cells.

  5. Impact of different alginate lyases on combined cellulase–lyase saccharification of brown seaweed

    DEFF Research Database (Denmark)

    Manns, Dirk Martin; Nyffenegger, Christian; Saake, B.;

    2016-01-01

    , indicating that the degradation of mannuronic acid blocks inhibited cellulase catalyzed glucose release from L. digitata. Nevertheless, combined alginate lyase and cellulase treatment for 24 hours released all potential glucose regardless of the applied lyase. The enzymatic treatment moreover induced......-guluronic acid. When applied together with a fungal cellulase preparation (Cellic®CTec2) at pH 6 and 40 °C on a glucan rich brown seaweed Laminaria digitata the viscosity decreased in the initial minutes while measurable alginate degradation occurred primarily within the first 1–2 hours of reaction. Whereas FALy...

  6. 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

    2016-01-01

    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.

  7. [Study on PVA-alginate co-immobilization of Xanthomonas ampelina TS206].

    Science.gov (United States)

    Chen, Qingsen; Liu, Jian

    2003-08-01

    Ice nucleation activity and anti-leaking capability are both important technical parameters in INA (Ice nucleation active bactetia) bacteria immobilization which can be adopted on freezing concentrate. Both PVA and alginate are good medium for immobilization. They can be used on co-immobilization of ice nucleation-active bacteria (Xanthomonas ampelinaTS206). The results showed that quantity of embedding affects ice nucleation activity greatly. The order of importance to comprehensive scores of technical standard should be concentration of Sodium alginate > Boric acid > PVA > CaCl2. The optimized concentration are PVA 8%, sodium alginate 1%, CaCl2 1.1% and boric acid 5%. A conclusion can be draw that ice nucleation activity increases with the number of beads and shows little pertinency with the time of immobilization, whereas anti-leaking capability can be influenced faintly by the number of beads and the time of immobilization. PMID:16276925

  8. 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.

  9. 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.

  10. 海藻酸钠接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料的制备与表征%Preparation and Characterization of Sodium Alginate with Acrylic Acid-acrylamide Copolymers/Attapulgite Composites

    Institute of Scientific and Technical Information of China (English)

    胡盛; 姚雪; 周红艳; 段雯怡; 田大听; 张升晖

    2012-01-01

    Sodium alginate grafted acrylic acid-acrylamide copolymers/attapulgite composite using sodium alginate( SA), acrylic acid( AA), acrylamide( AM)was synthesized by aqueous solution polymerization with and attapulgite(AT)as raw material, potassium persulfate as initiator, and N, N-methylene-bis-acrylamide as crosslinker. The effects of the synthesis factors on water absorbency were investigated. The composites were characterized by FTIR and SEM. The results showed that when the mass ratio of acrylamide: acrylic acid was 5:1, the content of sodium alginate, attapulgite, crosslinker and initiator was 15% , 25% , 0. 095% , 0. 55%(compare to the mass of monomer), respectively, and the absorbency of the composites was highest and the water absorbent rate of the sample was 1 693.3 g·g-1 at 80℃. The FT-IR spectra showed that sodium alginate and AT participated in graft polymerization reaction with A A and AM. The structure of the sodium alginate with acrylic acid-acrylamide copolymers/attapulgite composites shown by SEM was tight but own porous surface and different sizes of holes which are beneficial to improve the water absorbent rate.%以凹凸棒石(AT)为原料、过硫酸钾为引发剂、N,N-亚甲基双丙烯酰胺为交联剂、丙烯酰胺(AM)、丙烯酸(AA)两种单体同时对海藻酸钠(sA)进行接枝改性,采用水溶液聚合法制备了海藻酸钠接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料.考察了各合成因素对复合材料吸液倍率的影响,并采用FTIR、SEM对复合材料进行了表征.结果表明,当丙烯酰胺与丙烯酸的质量比为5∶1、海藻酸钠质量分数为15%(占单体丙烯酸质量,下同)、凹凸棒石用量为25%、交联剂用量为0.095%、引发剂用量为0.55%和反应温度为80℃时,制备的复合材料的吸蒸馏水倍率最高,达到l 693.3 g/g.FTIR表明,海藻酸钠、丙烯酸、丙烯酰胺和凹凸棒石共同参与了接枝聚合反应.SEM表明,凹凸棒石的引入,

  11. 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.

  12. 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

  13. Effects of Pectin, Xanthan Gum, Sodium Alginate and Acid-resistant CMC on Lactobacillus Contents of Silk Fibroin Yoghurt%果胶、黄原胶、海藻酸钠、耐酸性CMC对丝素酸奶乳酸菌数的影响

    Institute of Scientific and Technical Information of China (English)

    刘冠卉; 屠洁; 燕薇

    2012-01-01

    采用两因素三水平析因试验设计,考察了4种常用的酸奶稳定剂(果胶、黄原胶、海藻酸钠、耐酸性CMC)对搅拌型丝素酸奶乳酸菌数的影响.结果显示:果胶、黄原胶、海藻酸钠、耐酸性CMC对丝素酸奶的乳酸菌数均有极显著的影响(P<0.01),其中黄原胶、海藻酸钠和丝素对乳酸菌数有极显著的交互作用(P<0.01),果胶和丝素对乳酸菌含量有显著的交互作用(P<0.05),耐酸性CMC和丝素对酸奶的乳酸菌数无显著的交互作用(P>0.05).4种稳定剂中,黄原胶和海藻酸钠可提高搅拌型丝素酸奶的乳酸菌数,其中添加1%丝素和0.03%海藻酸钠的酸奶的乳酸菌数最高,达到1.20×1011 mL-1;其次为添加1%丝素和0.05%黄原胶的酸奶,乳酸菌数为1.07×1011mL-1.%Two factors and three levels factorial experiment design was used to study the effects of pectin, xanthan gum, sodium alginate, acidresistant carboxymethyl-cellulose on the lactobacillus contents of silk fibroin stirred yoghurt. Results showed pectin, xanthate gum, sodium alginate and acid-resistant carboxymethyl-cellulose had significant effects on lactobacillus contents of silk fibroin yogurt (P0.05). About three four stabilizers, xanthan gum and sodium alginate raised lactobacillus contents of silk fibroin stirred yoghurt, and the lactobacillus contents of stirred yoghurt including l%silk fibroin and 0.03% sodium alginate were highest(1.20×l011 mL-1), then that of the samples(l% silk fibroin and 0.05% xanthate gum) were 1.07× 1011 mL-1.

  14. 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)

  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. 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...

  17. 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.

  18. Differentiation of Wharton’s jelly mesenchymal stem cells into neurons in alginate scaffold

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

    Alginate scaffold has been considered as an appropriate biomaterial for promoting the differ-entiation 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 pro-mote 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 ifbroblast growth factor. These cells were also cultured in conventional two-dimensional culture condition in the presence of neurogenic medium as controls. After 10 days, immunolfuorescence staining was performed for detectingβ-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.

  19. Effects of Lactobacillus plantarum immobilization in alginate coated with chitosan and gelatin on antibacterial activity.

    Science.gov (United States)

    Trabelsi, Imen; Ayadi, Dorra; Bejar, Wacim; Bejar, Samir; Chouayekh, Hichem; Ben Salah, Riadh

    2014-03-01

    The present study aimed to investigate and evaluate the efficiency of immobilizing the Lactobacillus plantarum TN9 strain in alginate using chitosan and gelatin as coating materials, in terms of viability and antibacterial activity. The results indicate that maximum concentrations of L. plantarum TN9 strain were produced with 2% sodium alginate, 10(8)UFC/ml, and 1M calcium chloride. The viability and antibacterial activity of the L. plantarum TN9 cultures before and after immobilization in alginate, chitosan-coated alginate, and gelatin-coated alginate, were studied. The findings revealed that the viability of encapsulated L. plantarum could be preserved more than 5.8 log CFU/ml after 35 day of incubation at 4 °C, and no effects were observed when gelatin was used. The antibacterial activity of encapsulated L. plantarum TN9 against Gram-positive and Gram-negative pathogenic bacteria was enhanced in the presence of chitosan coating materials, and no activity was observed in the presence of gelatin. The effects of catalase and proteolytic enzymes on the culture supernatant of L. plantarum TN9 were also investigated, and the results suggested that the antibacterial activity observed was due to the production of organic acids. Taken together, the findings indicated that immobilization in chitosan enhanced the antibacterial activity of L. plantarum TN9 against several pathogenic bacteria. This encapsulated strain could be considered as a potential strong candidate for future application as an additive in the food and animal feed industries.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Alginate- and gellan-based edible films for probiotic coatings on fresh-cut fruits.

    Science.gov (United States)

    Tapia, M S; Rojas-Graü, M A; Rodríguez, F J; Ramírez, J; Carmona, A; Martin-Belloso, O

    2007-05-01

    Alginate- (2% w/v) or gellan-based (0.5%) edible films, containing glycerol (0.6% to 2.0%), N-acetylcysteine (1%), and/or ascorbic acid (1%) and citric acid (1%), were formulated and used to coat fresh-cut apple and papaya cylinders. Water vapor permeability (WVP) was significantly higher (P films (0.30 to 0.31 x 10(-9) g m/Pa s m2) than in the gellan ones (0.26 to 0.27 x 10(-9) g m/Pa s m2). Addition of 0.025% (w/v) sunflower oil decreased WVP of gellan films (0.20 to 0.22 x 10(-9) g m/Pa s m2). Water solubility of gellan and alginate films at 25 degrees C (0.47 to 0.59 and 0.74 to 0.79, respectively) and their swelling ratios (2.3 to 2.6 and 1.6 to 2.0, respectively) indicate their potential for coating high moisture fresh-cut fruits. Fresh-cut apple and papaya cylinders were successfully coated with 2% (w/v) alginate or gellan film-forming solutions containing viable bifidobacteria. WVP in alginate (6.31 and 5.52 x 10(-9) g m/Pa s m2) or gellan (3.65 and 4.89 x 10(-9) g m/Pa s m2) probiotic coatings of papaya and apple, respectively, were higher than in the corresponding cast films. The gellan coatings and films exhibited better water vapor properties in comparison with the alginate coatings. Values > 10(6) CFU/g B. lactis Bb-12 were maintained for 10 d during refrigerated storage of fresh-cut fruits, demonstrating the feasibility of alginate- and gellan-based edible coatings to carry and support viable probiotics on fresh-cut fruit.

  6. Alginate-Chitosan Microcapsules for Renal Arterial Embolization

    Institute of Scientific and Technical Information of China (English)

    LI Sha; HOU Xin-pu

    2003-01-01

    @@ Two natural, nontoxic, biodegradable and well biocompatible polyelectrolyte polymers, sodium alginate (Alg) and chitosan (CTS), which contain opposite charges, were selected to establish alginate-chitosan microcapsules by electrostatic interaction.

  7. 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.

  8. 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

  9. 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)

  10. Electrospun Sodium Alginate/Polyethylene Oxide Fibers and Nanocoated Yarns

    Directory of Open Access Journals (Sweden)

    C. Hu

    2015-01-01

    Full Text Available Sodium alginate (NaAlg, as a natural biopolymer, was electrospun from aqueous solution via blending with a biofriendly synthetic polymer polyethylene oxide. The morphology and chemical properties of resultant alginate-based nanofibers were characterized by using scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, powder X-ray diffractometer (PXRD, and differential scanning calorimetry (DSC. At a wide voltage window (i.e., 12–24 kV, smooth and uniform nanofibers were obtained from the 5.0% concentration with the NaAlg/PEO ratio ranging from 1 : 1 to 1 : 3. The results from FTIR, PXRD, and DSC demonstrate that molecular interaction exists between these two polymers and, therefore, contributes to the alteration of crystallinity of electrospun fibers. In addition, NaAlg/PEO nanofiber-coated polylactic acid (PLA yarns with different twist levels were also fabricated in this work. The results show that the tensile strength of the nanocoated hybrid yarn and the tensile strength of uncoated yarn increase with the twist per centimeter (TPC up to 0.5 but decrease when TPC is further increased. The tensile properties of hybrid yarn are superior to those of the uncoated yarn.

  11. 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

  12. THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

    Institute of Scientific and Technical Information of China (English)

    Qing-shan Kong; Bing-bing Wang; Quan Ji; Yan-zhi Xia; Zhao-xia Guo; Jian Yu

    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 combustion are much lower compared with those of viscose fibers. Calcium carbonate and calcium oxide were formed during thermal degradation of calcium alginate fibers at different temperatures. The shape of calcium alginate fibers is well kept after LOI test. The rigid combustion residue char acts as an effective barrier to the outward diffusion of flame and heat. The combustion process and flame retardant mechanism of calcium alginate fibers are also discussed.

  13. 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

  14. 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.

  15. 21 CFR 184.1610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ...: Category of food Maximum level of use in food (as served) (percent) Functional use Confections and... 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...

  16. 21 CFR 184.1133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ...: Category of food Maximum level of use in food (as served) (percent) Functional use Confections, frostings... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  17. Cd(II) Speciation in alginate gels

    NARCIS (Netherlands)

    Davis, T.A.; Kalis, E.J.J.; Pinheiro, J.P.; Town, R.M.; Leeuwen, van H.P.

    2008-01-01

    Polysaccharides, such as those occurring in cell walls and biofilms, play an important role in metal speciation in natural aqueous systems. This work describes the speciation of Cd(II) in alginate gels chosen as a model system for biogels. The gels are formed by bridging calcium ions at junction zon

  18. An effective device for generating alginate microcapsules

    Directory of Open Access Journals (Sweden)

    Tatiana A.B. Bressel

    2008-01-01

    Full Text Available An alternative approach to somatic gene therapy is to deliver the therapeutic protein by implanting genetically modified cells that could overexpress the gene of interest. Microencapsulation devices were designed to protect cells from host rejection and prevent the foreign cells from spreading while allowing protein secretion. Alginate microcapsules form a semi-permeable structure that is suitable for in vivo injection. In this study, we report an effective laboratory protocol for producing calcium alginate microcapsules, following optimization of uniformly shaped and sized particles containing viable cells. Encapsulation of baby hamster kidney (BHK cells in alginate microcapsules was performed using a simple device consisting of a cylinder of compressed air and a peristaltic pump. A cell suspension flow of 100 mL h-1 and an air jet flow of 10 L min-1 produced the best uniformity of microcapsule size and shape. Cells maintained viability in culture for 4 weeks without any signs of necrosis, and protein diffusion was observed during this period. Our results clearly demonstrated that microisolation of BHK cells in alginate using a simple assembly device could provide an environment that is capable of preserving live cells. In addition, encapsulated cells under the conditions described were able to secrete an active enzyme even after four weeks, thus becoming potentially compatible with therapeutic protein delivery.

  19. Study on Preparation and Properties of Polyacrylic Acid-sodium Alginate Absorbent Resin%聚丙烯酸-海藻酸钠吸水树脂的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    黄慧珍

    2012-01-01

    A salt-tolerant super absorbent resin was obtained by crosslinking copolymerization,using acryhcaeid,acrylamide,and sodium alginate.Aqueous solution polymerization method was used for improving properties of absorbent resin,which would be affected by the amount of crosslinking agent,initiator and acrylamide.It showed that the water absorption rate can reach 830 g/g,and the salt absorption rate can reach 81 g/g.%以丙烯酸为单体,海藻酸钠为接枝物,添加丙烯酰胺,通过溶液聚合法制备复合型耐盐高吸水性树脂。研究了聚丙烯酸-海藻酸钠高吸水树脂的吸水性能。结果表明,在蒸馏水、生理盐水中吸水倍率分别达到830 g/g、81 g/g。天然高分子海藻酸钠具有很好的耐盐性,海藻酸钠的加入,提高了高吸水性复合材料的耐盐性。

  20. 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

  1. 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)

  2. 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 ...

  3. 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.

  4. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions.

    Science.gov (United States)

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source. PMID:25880041

  5. Flame retardant properties of calcium alginate fibers%海藻酸钙纤维的阻燃性能

    Institute of Scientific and Technical Information of China (English)

    张传杰; 张楠楠; 王臻; 朱平

    2011-01-01

    The flame retardant property of calcium alginate fibers is characterized by limiting oxygen index method and cone calorimeter.The resutts show that the limiting oxygen index of calcium alginate fibers is 34.4% , no flame burning in air and extinguishes instantly as soon as they are moved away from fire.During combustion process, the heat release rata ( HRR) , effective heat of combustion ( EHC) and total heat release ( THR) of calcium alginate fibers are lower while carbon dioxide yield rate of calcium alginate fibers is high, which means calcium alginate fibers have excellent flame retardant property.Thermal degradation and component of pyrolysis products of calcium alginate fibers are investigated by thermal gravimetry, X-ray diffraction and pyrolysis-gas chromatography-mass spectrometry.The reasons for flame retardancy of calcium alginate fibers are the special structure of alginic acid macromolecules which are the components of calcium alginate fibers and the effect of calcium ions contained in fibers.%采用氧指数法和锥形量热仪测试海藻酸钙纤维的阻燃性能,结果表明,海藻酸钙纤维具有优异的阻燃性能.其极限氧指数为34.4%,在空气中离火自熄;且燃烧过程中的热释放速率、有效燃烧热和总放热量比较低,二氧化碳的生成速率比较高.采用热重分析仪、X-射线衍射仪和裂解-气相色谱-质谱联用仪研究海藻酸钙纤维的热分解过程以及不同裂解阶段的凝聚相裂解产物和气相裂解产物,发现海藻酸钙纤维具有阻燃性的原因在于组成纤维的海藻酸大分子的特殊结构,以及纤维中钙离子的作用.

  6. 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 ...

  7. 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.

  8. 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...

  9. 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

  10. 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.

  11. Effect of sodium-alginate and laminaran on Salmonella Typhimurium infection in human enterocyte-like HT-29-Luc cells and BALB/c mice.

    Science.gov (United States)

    Kuda, Takashi; Kosaka, Misa; Hirano, Shino; Kawahara, Miho; Sato, Masahiro; Kaneshima, Tai; Nishizawa, Makoto; Takahashi, Hajime; Kimura, Bon

    2015-07-10

    Brown algal polysaccharides such as alginate, polymers of uronic acids, and laminaran, beta-1,3 and 1,6-glucan, can be fermented by human intestinal microbiota. To evaluate the effects of these polysaccharides on infections caused by food poisoning pathogens, we investigated the adhesion and invasion of pathogens (Salmonella Typhimurium, Listeria monocytogenes and Vibrio parahaemolyticus) in human enterocyte-like HT-29-Luc cells and in infections caused in BALB/c mice. Both sodium Na-alginate and laminaran (0.1% each) inhibited the adhesion of the pathogens to HT-29-Luc cells by approximately 70-90%. The invasion of S. Typhimurium was also inhibited by approximately 70 and 80% by Na-alginate and laminaran, respectively. We observed that incubation with Na-alginate for 18 h increased the transepithelial electrical resistance of HT-29-Luc monolayer cells. Four days after inoculation with 7 log CFU/mouse of S. Typhimurium, the faecal pathogen count in mice that were not fed polysaccharides (control mice) was about 6.5 log CFU/g while the count in mice that were fed Na-alginate had decreased to 5.0 log CFU/g. The liver pathogen count, which was 4.1 log CFU/g in the control mice, was also decreased in mice that were fed Na-alginate. In contrast, the mice that were fed laminaran exhibited a more severe infection than that exhibited by control mice.

  12. Molecular insight into the role of the N-terminal extension in the maturation, substrate recognition, and catalysis of a bacterial alginate lyase from polysaccharide lyase family 18.

    Science.gov (United States)

    Dong, Sheng; Wei, Tian-Di; Chen, Xiu-Lan; Li, Chun-Yang; Wang, Peng; Xie, Bin-Bin; Qin, Qi-Long; Zhang, Xi-Ying; Pang, Xiu-Hua; Zhou, Bai-Cheng; Zhang, Yu-Zhong

    2014-10-24

    Bacterial alginate lyases, which are members of several polysaccharide lyase (PL) families, have important biological roles and biotechnological applications. The mechanisms for maturation, substrate recognition, and catalysis of PL18 alginate lyases are still largely unknown. A PL18 alginate lyase, aly-SJ02, from Pseudoalteromonas sp. 0524 displays a β-jelly roll scaffold. Structural and biochemical analyses indicated that the N-terminal extension in the aly-SJ02 precursor may act as an intramolecular chaperone to mediate the correct folding of the catalytic domain. Molecular dynamics simulations and mutational assays suggested that the lid loops over the aly-SJ02 active center serve as a gate for substrate entry. Molecular docking and site-directed mutations revealed that certain conserved residues at the active center, especially those at subsites +1 and +2, are crucial for substrate recognition. Tyr(353) may function as both a catalytic base and acid. Based on our results, a model for the catalysis of aly-SJ02 in alginate depolymerization is proposed. Moreover, although bacterial alginate lyases from families PL5, 7, 15, and 18 adopt distinct scaffolds, they share the same conformation of catalytic residues, reflecting their convergent evolution. Our results provide the foremost insight into the mechanisms of maturation, substrate recognition, and catalysis of a PL18 alginate lyase.

  13. 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.

  14. 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

  15. Characterization of algG encoding C5-epimerase in the alginate biosynthetic gene cluster of Pseudomonas fluorescens.

    Science.gov (United States)

    Morea, A; Mathee, K; Franklin, M J; Giacomini, A; O'Regan, M; Ohman, D E

    2001-10-31

    The organization of the alginate gene cluster in Pseudomonas fluorescens was characterized. A bank of genomic DNA from P. fluorescens was mobilized to a strain of Pseudomonas aeruginosa with a transposon insertion (algJ::Tn501) in the alginate biosynthetic operon that rendered it non-mucoid. Phenotypic complementation in this heterologous host was observed, and a complementing clone containing 32 kb of P. fluorescens DNA was obtained. Southern hybridization studies showed that genes involved in alginate biosynthesis (e.g. algD, algG, and algA) were approximately in the same order and position as in P. aeruginosa. When the clone was mobilized to a P. aeruginosa algG mutant that produced alginate as polymannuronate due to its C5-epimerase defect, complementation was observed and the alginate from the recombinant strain contained L-guluronate as determined by proton nuclear magnetic resonance spectroscopy. A sequence analysis of the P. fluorescens DNA containing algG revealed sequences similar to P. aeruginosa algG that were also flanked by algE- and algX-like sequences. The predicted AlgG amino acid sequence of P. fluorescens was 67% identical (80% similar) to P. aeruginosa AlgG and 60% identical (76% similar) to Azotobacter vinelandii AlgG. As in P. aeruginosa, AlgG from P. fluorescens appeared to have a signal sequence that would localize it to the periplasm where AlgG presumably acts as a C5-epimerase at the polymer level. Non-polar algG knockout mutants of P. fluorescens were defective in alginate production, suggesting a potential role for this protein in polymer formation.

  16. Viper and cobra venom neutralization by alginate coated multicomponent polyvalent antivenom administered by the oral route.

    Directory of Open Access Journals (Sweden)

    Sourav Bhattacharya

    2014-08-01

    Full Text Available Snake bite causes greater mortality than most of the other neglected tropical diseases. Snake antivenom, although effective in minimizing mortality in developed countries, is not equally so in developing countries due to its poor availability in remote snake infested areas as, and when, required. An alternative approach in this direction could be taken by making orally deliverable polyvalent antivenom formulation, preferably under a globally integrated strategy, for using it as a first aid during transit time from remote trauma sites to hospitals.To address this problem, multiple components of polyvalent antivenom were entrapped in alginate. Structural analysis, scanning electron microscopy, entrapment efficiency, loading capacity, swelling study, in vitro pH sensitive release, acid digestion, mucoadhesive property and venom neutralization were studied in in vitro and in vivo models. Results showed that alginate retained its mucoadhesive, acid protective and pH sensitive swelling property after entrapping antivenom. After pH dependent release from alginate beads, antivenom (ASVS significantly neutralized phospholipaseA2 activity, hemolysis, lactate dehydrogenase activity and lethality of venom. In ex vivo mice intestinal preparation, ASVS was absorbed significantly through the intestine and it inhibited venom lethality which indicated that all the components of antivenom required for neutralization of venom lethality were retained despite absorption across the intestinal layer. Results from in vivo studies indicated that orally delivered ASVS can significantly neutralize venom effects, depicted by protection against lethality, decreased hemotoxicity and renal toxicity caused by russell viper venom.Alginate was effective in entrapping all the structural components of ASVS, which on release and intestinal absorption effectively reconstituted the function of antivenom in neutralizing viper and cobra venom. Further research in this direction can

  17. Alginate-based hybrid aerogel microparticles for mucosal drug delivery.

    Science.gov (United States)

    Gonçalves, V S S; Gurikov, P; Poejo, J; Matias, A A; Heinrich, S; Duarte, C M M; Smirnova, I

    2016-10-01

    The application of biopolymer aerogels as drug delivery systems (DDS) has gained increased interest during the last decade since these structures have large surface area and accessible pores allowing for high drug loadings. Being biocompatible, biodegradable and presenting low toxicity, polysaccharide-based aerogels are an attractive carrier to be applied in pharmaceutical industry. Moreover, some polysaccharides (e.g. alginate and chitosan) present mucoadhesive properties, an important feature for mucosal drug delivery. This feature allows to extend the contact of DDS with biological membranes, thereby increasing the absorption of drugs through the mucosa. Alginate-based hybrid aerogels in the form of microparticles (aerogel microparticles were obtained for alginate, hybrid alginate/pectin and alginate/κ-carrageenan aerogels, presenting high specific surface area (370-548m(2)g(-1)) and mucoadhesive properties. The microparticles were loaded with ketoprofen via adsorption from its solution in sc-CO2, and with quercetin via supercritical anti-solvent precipitation. Loading of ketoprofen was in the range between 17 and 22wt% whereas quercetin demonstrated loadings of 3.1-5.4wt%. Both the drugs were present in amorphous state. Loading procedure allowed the preservation of antioxidant activity of quercetin. Release of both drugs from alginate/κ-carrageenan aerogel was slightly faster compared to alginate/pectin. The results indicate that alginate-based aerogel microparticles can be viewed as promising matrices for mucosal drug delivery applications.

  18. Alginate-based hybrid aerogel microparticles for mucosal drug delivery.

    Science.gov (United States)

    Gonçalves, V S S; Gurikov, P; Poejo, J; Matias, A A; Heinrich, S; Duarte, C M M; Smirnova, I

    2016-10-01

    The application of biopolymer aerogels as drug delivery systems (DDS) has gained increased interest during the last decade since these structures have large surface area and accessible pores allowing for high drug loadings. Being biocompatible, biodegradable and presenting low toxicity, polysaccharide-based aerogels are an attractive carrier to be applied in pharmaceutical industry. Moreover, some polysaccharides (e.g. alginate and chitosan) present mucoadhesive properties, an important feature for mucosal drug delivery. This feature allows to extend the contact of DDS with biological membranes, thereby increasing the absorption of drugs through the mucosa. Alginate-based hybrid aerogels in the form of microparticles (aerogel microparticles were obtained for alginate, hybrid alginate/pectin and alginate/κ-carrageenan aerogels, presenting high specific surface area (370-548m(2)g(-1)) and mucoadhesive properties. The microparticles were loaded with ketoprofen via adsorption from its solution in sc-CO2, and with quercetin via supercritical anti-solvent precipitation. Loading of ketoprofen was in the range between 17 and 22wt% whereas quercetin demonstrated loadings of 3.1-5.4wt%. Both the drugs were present in amorphous state. Loading procedure allowed the preservation of antioxidant activity of quercetin. Release of both drugs from alginate/κ-carrageenan aerogel was slightly faster compared to alginate/pectin. The results indicate that alginate-based aerogel microparticles can be viewed as promising matrices for mucosal drug delivery applications. PMID:27393563

  19. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  20. 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

  1. Time-Dependent Effect of Encapsulating Alginate Hydrogel on Neurogenic Potential

    Science.gov (United States)

    Razavi, Shahnaz; Khosravizadeh, Zahra; Bahramian, Hamid; Kazemi, Mohammad

    2015-01-01

    Objective Due to the restricted potential of neural stem cells for regeneration of central nervous system (CNS) after injury, providing an alternative source for neural stem cells is essential. Adipose derived stem cells (ADSCs) are multipotent cells with properties suitable for tissue engineering. In addition, alginate hydrogel is a biocompatible polysaccharide polymer that has been used to encapsulate many types of cells. The aim of this study was to assess the proliferation rate and level of expression of neural markers; NESTIN, glial fibrillary acidic protein (GFAP) and microtubule-associated protein 2 (MAP2) in encapsulated human ADSCs (hADSCs) 10 and14 days after neural induction. Materials and Methods In this experimental study, ADSCs isolated from human were cultured in neural induction media and seeded into alginate hydrogel. The rate of proliferation and differentiation of encapsulated cells were evaluated by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) assay, immunocytoflourescent and realtime reverse transcriptase polymerase chain reaction (RT-PCR) analyzes 10 and 14 days after induction. Results The rate of proliferation of encapsulated cells was not significantly changed with time passage. The expression of NESTIN and GFAP significantly decreased on day 14 relative to day 10 (P<0.001) but MAP2 expression was increased. Conclusion Alginate hydrogel can promote the neural differentiation of encapsulated hADSCs with time passage. PMID:26199909

  2. 海藻酸钙固定化乳酸菌连续化预发酵生产酸奶%Study on Continuous Pre-fermentation for Production of Yogurt by Encapsulated Lactic Acid Bacteria in Calcium Alginate Immobilized System

    Institute of Scientific and Technical Information of China (English)

    包永华; 董明盛

    2012-01-01

    Two strains of lactic acid bacteria ( Lactobacillus delbruekii ssp. Bulgaricus and Streptococcus salivarius ssp. Thermophilus )were immobilized separately in liquid-core alginate capsules and used for continuous inoculation- prefermentation of milk for yoghurt production in a stirred tank reactor. The result showed that the coagulum time was shortened with the increase of temperature under the lower level pH. The effect of stirring speed on the dilution rate was significant. The dilution rate decreased as stirring speed increased. The inoculation of pre-fermented milk (total number of bacteria) were unaffected by pre-fermentation temperature, pH and stirring speed. In all cases, pre-fer- mented milk was inoculated at 10^8 CFU/mL.%将唾液链球菌嗜热亚种、德氏乳杆菌保加利亚亚种分别固定化于海藻酸钙形成的液芯包囊中,在一个连续搅拌反应器中对牛奶进行连续化接种,预发酵生产酸奶。试验结果表明,随着温度的升高和pH值的降低,凝乳时间都呈缩短的趋势。生物反应器的搅拌速度对稀释率影响显著,随着搅拌速度增加,稀释度明显下降。温度、pH值和搅拌速度对连续接种牛奶的接种量影响不显著,预发酵牛奶的接种量(总细菌数)均达到了10^8CFU/mL。

  3. 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

  4. 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

  5. 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

  6. Chitosan-alginate membranes accelerate wound healing.

    Science.gov (United States)

    Caetano, Guilherme Ferreira; Frade, Marco Andrey Cipriani; Andrade, Thiago Antônio Moretti; Leite, Marcel Nani; Bueno, Cecilia Zorzi; Moraes, Ângela Maria; Ribeiro-Paes, João Tadeu

    2015-07-01

    The purpose of this study was to evaluate the efficacy of chitosan-alginate membrane to accelerate wound healing in experimental cutaneous wounds. Two wounds were performed in Wistar rats by punching (1.5 cm diameter), treated with membranes moistened with saline solution (CAM group) or with saline only (SL group). After 2, 7, 14, and 21 days of surgery, five rats of each group were euthanized and reepithelialization was evaluated. The wounds/scars were harvested for histological, flow cytometry, neutrophil infiltrate, and hydroxyproline analysis. CAM group presented higher inflammatory cells recruitment as compared to SL group on 2(nd) day. On the 7(th) day, CAM group showed higher CD11b(+) level and lower of neutrophils than SL group. The CAM group presented higher CD4(+) cells influx than SL group on 2(nd) day, but it decreased during the follow up and became lower on 14(th) and 21(st) days. Higher fibroplasia was noticed on days 7 and 14 as well as higher collagenesis on 21(st) in the CAM group in comparison to SL group. CAM group showed faster reepithelialization on 7(th) day than SL group, although similar in other days. In conclusion, chitosan-alginate membrane modulated the inflammatory phase, stimulated fibroplasia and collagenesis, accelerating wound healing process in rats.

  7. Removal of radioactive nuclides by alginate microcapsules

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, H.; Oritani, T.; Akiba, K. [Tohoku Univ., Institute of Multidisciplinary Research for Advanced Materials, Sendai, Miyagi (Japan)

    2002-11-01

    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The K{sub d} values of Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Y{sup 3+}, Eu{sup 3+} and Am{sup 3+}, for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were estimated to be 1.1x10{sup 4}, 7.5x10, 1.1x10, 1.0x10{sup 4}, 1.4x10{sup 4}, 3.4x10{sup 3} cm{sup 3}/g, respectively. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into the gelling salt solutions. The alginate microcapsules have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions. (author)

  8. 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.

  9. 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.

  10. 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, ...

  11. Encapsulation of liquid smoke flavoring in ca-alginate and ca-alginate-chitosan beads.

    Science.gov (United States)

    Petzold, Guillermo; Gianelli, María Pia; Bugueño, Graciela; Celan, Raymond; Pavez, Constanza; Orellana, Patricio

    2014-01-01

    Encapsulation is a technique used in foods that may protect some compounds with sensory impact, in particular flavoring as liquid smoke. We used the dripping method, obtaining two different layers for encapsulation of liquid smoke: calcium alginate and calcium alginate-chitosan. The results show that the load capacity of liquid smoke encapsulation reached values above 96 %. The beads exhibit syneresis at room temperature, but in opposite side, refrigeration temperature stabilizes the hydrogel of beads, allowing the samples loss weight less than 3 % after 72 h. Heated capsules with liquid smoke released several volatile compounds in the headspace and may identify 66 compounds. Among these volatile compounds, phenols derivatives can be considered sensory descriptors to contribute to the specific flavor of smoke. We conclude that the dripping method is highly efficient to encapsulate liquid smoke and released several volatile compounds, although it is necessary to minimize syneresis at room temperature.

  12. 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

    determined by confocal microscopy, dendritic cell co-culture, flow cytometry, reverse transcriptase quantitative polymerase chain reaction, Luminex multiplex, and lymphocyte proliferation experiments. RESULTS: ASCs performed equally well in alginate and RGD-alginate. After 1 week of alginate culture, cell...... viability was >93%. Mesenchymal markers CD90 and CD29 were reduced compared with International Society for Cellular Therapy criteria. Cells sedimented from the alginates during cultivation regained the typical level of these markers, and trilineage differentiation was performed by standard protocols....... Hepatocyte growth factor mRNA was increased in ASCs cultivated in alginates compared with monolayer controls. Alginates and alginates containing ASCs did not induce dendritic cell maturation. ASCs in alginate responded like controls to interferon-gamma stimulation (licensing), and alginate culture increased...

  13. Preparation of novel silica-coated alginate gel beads for efficient encapsulation of yeast alcohol dehydrogenase.

    Science.gov (United States)

    Xu, Song-Wei; Lu, Yang; Li, Jian; Zhang, Yu-Fei; Jiang, Zhong-Yi

    2007-01-01

    Biomimetic formation has undoubtedly inspired the preparation of novel organic-inorganic hybrid composites. In this study, silica-coated alginate gel beads were prepared by coating the surface of alginate gel beads with silica film derived from tetramethoxysilane (TMOS). The composition and structure of the silica film were characterized by FT-IR and SEM equipped with EDX. The swelling behavior of silica-coated alginate gel beads was studied to be more stable against swelling than that of alginate gel beads. The results showed that silica-coated alginate gel beads exhibited appropriate diffusion property. The effective diffusion coefficient (D(e)) of NADH in silica-coated alginate beads was 1.76 x 10(-10) m2/s, while the effective diffusion coefficient in alginate beads was 1.84 x 10(-10) m2/s. The model enzyme yeast alcohol dehydrogenase (YADH) was encapsulated in silica-coated alginate and pure alginate beads, respectively. Enzyme leakage of YADH in alginate gel beads was determined to be 32%, while the enzyme leakage in silica-coated alginate gel beads was as low as 11%. Furthermore, the relative activity of YADH in alginate gel beads decreased almost to zero after 10 recycles, while the relative activity of YADH in silica-coated alginate gel beads was 81.3%. The recycling stability of YADH in silica-coated alginate gel beads was found to be increased significantly mainly due to the effective inhibition of enzyme leakage by compact silica film.

  14. Development of functionalized multi-walled carbon-nanotube-based alginate hydrogels for enabling biomimetic technologies

    Science.gov (United States)

    Joddar, Binata; Garcia, Eduardo; Casas, Atzimba; Stewart, Calvin M.

    2016-08-01

    Alginate is a hydrogel commonly used for cell culture by ionically crosslinking in the presence of divalent Ca2+ ions. However these alginate gels are mechanically unstable, not permitting their use as scaffolds to engineer robust biological bone, breast, cardiac or tumor tissues. This issue can be addressed via encapsulation of multi-walled carbon nanotubes (MWCNT) serving as a reinforcing phase while being dispersed in a continuous phase of alginate. We hypothesized that adding functionalized MWCNT to alginate, would yield composite gels with distinctively different mechanical, physical and biological characteristics in comparison to alginate alone. Resultant MWCNT-alginate gels were porous, and showed significantly less degradation after 14 days compared to alginate alone. In vitro cell-studies showed enhanced HeLa cell adhesion and proliferation on the MWCNT-alginate compared to alginate. The extent of cell proliferation was greater when cultured atop 1 and 3 mg/ml MWCNT-alginate; although all MWCNT-alginates lead to enhanced cell cluster formation compared to alginate alone. Among all the MWCNT-alginates, the 1 mg/ml gels showed significantly greater stiffness compared to all other cases. These results provide an important basis for the development of the MWCNT-alginates as novel substrates for cell culture applications, cell therapy and tissue engineering.

  15. Characterization of gelatin-sodium alginate complex coacervation system

    Directory of Open Access Journals (Sweden)

    Shinde Ujwala

    2009-01-01

    Full Text Available A gelatin and sodium alginate complex coacervation system was studied and an effect of pH and colloid mixing ratios on coacervation was investigated. A colloid mixing ratio at which optimum coacervation occurred varied with the coacervation pH. Viscometric, turbidity and coacervate dry yield investigations were used to investigate optimum conditions for complex coacervation. Optimum coacervation occurred at pH 3.5 at a gelatin sodium alginate ratio 4:1. Coacervate and equilibrium fluid was analyzed for gelatin and sodium alginate contents and yields calculated on the basis of chemical analysis showed that optimum coacervation occurred at 25% sodium alginate fraction at pH 3.5.

  16. 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.

  17. 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.

  18. Encapsulation of sorbitan ester-based organogels in alginate microparticles.

    Science.gov (United States)

    Sagiri, Sai S; Pal, Kunal; Basak, Piyali; Rana, Usman Ali; Shakir, Imran; Anis, Arfat

    2014-10-01

    Leaching of the internal apolar phase from the biopolymeric microparticles during storage is a great concern as it undoes the beneficial effects of encapsulation. In this paper, a novel formulation was prepared by encapsulating the sunflower oil-based organogels in alginate microparticles. Salicylic acid and metronidazole were used as the model drugs. The microparticles were prepared by double emulsion methodology. Physico-chemical characterization of the microparticles was done by microscopy, FTIR, XRD, and DSC studies. Oil leaching studies, biocompatibility, mucoadhesivity, in vitro drug release, and the antimicrobial efficiency of the microparticles were also performed. The microparticles were found to be spherical in shape. Gelation of the sunflower oil prevented leaching of the internal phase from the microparticles. Release of drugs from the microparticles followed Fickian kinetics and non-Fickian kinetics in gastric and intestinal environments, respectively. Microparticles showed good antimicrobial activity against both Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria. The results suggested that the developed formulations hold promise to carry oils without leakage of the internal phase. Encapsulation of organogels within the microparticles has improved the drug entrapment efficiency and improved characteristics for controlled delivery applications.

  19. Complex Coacervation composed of Polyelectrolytes Alginate and Chitosan

    Institute of Scientific and Technical Information of China (English)

    盛楠楠

    2016-01-01

    Alginate sodium (ALG) and chitosan (CHI) can form fiber, films, microspheres, hydrogels and all with a wide range of biomedical applications.Few works have been done as a result of the easily flocculation of chitosan in negatively charged matrix.Complex coacervation composed of polyelectrolytes alginate and chitosan were successfully fabricated.The results showed that the lower molecular weights of the chitosan is better for the fabricated of the complex coacervation.

  20. Microfluidic generation of hollow Ca-alginate microfibers.

    Science.gov (United States)

    Meng, Zhi-Jun; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

    2016-07-01

    This work reports on an efficient microfluidic approach for continuous production of hollow Ca-alginate microfibers with controllable structures and functions. A coaxial microcapillary microfluidic device combined with a rotator is constructed to produce a cylindrical flow jet with four aqueous solutions as templates for continuous fabrication and collection of microfibers. A four-aqueous-phase flow jet with an intermediate buffer flow between the Ca(2+)-containing and alginate-containing flows is used as the template for microfiber fabrication. The buffer flow efficiently controls the diffusion of Ca(2+) into the alginate-containing flow as well as the crosslinking reaction, thus ensuring the continuous fabrication of hollow Ca-alginate microfibers under relatively low flow rates without clogging of the microchannel. The structure of the hollow microfibers can be flexibly adjusted by changing the flow rates and device dimensions. Meanwhile, the continuous fabrication process of the microfibers allows flexible incorporation of a functional component into the sheath flow for functionalization and addition of active substances in the core flow for encapsulation. This is demonstrated by fabricating hollow Ca-alginate microfibers with a wall containing magnetic nanoparticles for magnetic functionalization and with hollow internals containing Chlorella pyrenoidosa cells for confined growth. This work provides an efficient strategy for continuous fabrication of functional hollow Ca-alginate microfibers with controllable structures and functions. PMID:27302737

  1. 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)

  2. Study of the interpolyelectrolyte reaction between chitosan and alginate: influence of alginate composition and chitosan molecular weight.

    Science.gov (United States)

    Becherán-Marón, L; Peniche, C; Argüelles-Monal, W

    2004-04-01

    The interpolyelectrolyte reaction between chitosan (CHI) and alginate (ALG) was followed by conductimetry and potentiometry. Five chitosan samples, all with almost the same degree of N-acetylation (DA approximately 0.20) and molecular weights ranging from 5 x 10(3) to 2.5 x 10(5) Da were used. The polyelectrolyte complex was formed using alginate samples with three different M/G values (0.44, 1.31 and 1.96). The composition of the complex, Z (Z = [CHI]/[ALG]) resulted 0.70 +/- 0.02, independently of the molecular weight of chitosan and the composition of the alginate used. The degree of complexation was 0.51 with no dependence on the alginate composition.

  3. 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

  4. Discovery of a Novel Alginate Lyase from Nitratiruptor sp. SB155-2 Thriving at Deep-sea Hydrothermal Vents and Identification of the Residues Responsible for Its Heat Stability.

    Science.gov (United States)

    Inoue, Akira; Anraku, Moe; Nakagawa, Satoshi; Ojima, Takao

    2016-07-22

    Extremophiles are expected to represent a source of enzymes having unique functional properties. The hypothetical protein NIS_0185, termed NitAly in this study, was identified as an alginate lyase-homolog protein in the genomic database of ϵ-Proteobacteria Nitratiruptor sp. SB155-2, which was isolated from deep-sea hydrothermal vents at a water depth of 1,000 m. Among the characterized alginate lyases in the polysaccharide lyase family 7 (PL-7), the amino acid sequence of NitAly showed the highest identity (39%) with that of red alga Pyropia yezoensis alginate lyase PyAly. Recombinant NitAly (rNitAly) was successfully expressed in Escherichia coli Purified rNitAly degraded alginate in an endolytic manner. Among alginate block types, polyM was preferable to polyG and polyMG as a substrate, and its end degradation products were mainly tri-, tetra-, and penta-saccharides. The optimum temperature and pH values were 70 °C and around 6, respectively. A high concentration of NaCl (0.8-1.4 m) was required for maximum activity. In addition, a 50% loss of activity was observed after incubation at 67 °C for 30 min. Heat stability was decreased in the presence of 5 mm DTT, and Cys-80 and Cys-232 were identified as the residues responsible for heat stability but not lyase activity. Introducing two cysteines into PyAly based on homology modeling using Pseudomonas aeruginosa alginate lyase PA1167 as the template enhanced its heat stability. Thus, NitAly is a functional alginate lyase, with its unique optimum conditions adapted to its environment. These insights into the heat stability of NitAly could be applied to improve that of other PL-7 alginate lyases. PMID:27231344

  5. Immobilization of phospholipase a1 using a polyvinyl alcohol-alginate matrix and evaluation of the effects of immobilization

    Directory of Open Access Journals (Sweden)

    J. F. Zhan

    2013-12-01

    Full Text Available The paper presents the synthesis and performance of an immobilized phospholipase A1 with practical application for oil degumming. The polyvinyl alcohol (PVA had a number of properties indicating this polymer as a good enzyme carrier. The combination with alginate made a macro-porous structure, evidenced by SEM analyses. When the process time in boric acid solution was 30 minutes, the results revealed that beads prepared with 10% (w/v PVA and 2% (w/v sodium alginate in 4% (w/v boric acid and 2% (w/v calcium chloride solution exhibited high immobilized enzyme activity, immobilization yield and stability. The pH and temperature optimum for the PVA-alginate immobilized phospholipase A1were 5.6 and 58 °C, respectively. The enzyme immobilized in the beads retained 50.37% of the initial activity in the eighth cycle. The enzyme biocatalyst immobilized in the beads retained 78.58% of the initial activity after storing 6 weeks at 4 °C.

  6. Comparative equilibrium studies of sorption of Pb(II) ions by sodium and calcium alginate

    Institute of Scientific and Technical Information of China (English)

    KHOTIMCHENKO Maxim; KOVALEV Valeri; KHOTIMCHENKO Yuri

    2008-01-01

    The absorption of Pb(II) ions from aqueous solution by different alginate compounds was studied in a batch sorption system. Water soluble sodium alginate and insoluble calcium alginate beads were investigated. The lead-binding capacity of both alginate compounds was highest within the pH range 6-8. The binding capacities and rates of Pb(II) ions by alginate compounds were evaluated. The Langmuir, Freundlich and Bruneaur, Emmet and Teller (BET) sorption models were applied to describe the isotherms and isotherm constants. Sorption isothermal data could be well interpreted by the Langmuir model. The results obtained through the study suggest that alginate compounds are favorable sorbents. The largest amount of Pb(II) ions were bound by sodium alginate although the difference between two compounds was slight. Therefore, alginate substances may be considered as alternative for sorption and removal of Pb(II) ions from wastewaters.

  7. 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.

  8. 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)

  9. An investigation of agitation speed as a factor affecting the quantity and monomer distribution of alginate from Azotobacter vinelandii ATCC(®) 9046.

    Science.gov (United States)

    Kıvılcımdan Moral, C; Sanin, F D

    2012-03-01

    Alginate is a copolymer of β-D: -mannuronic and α-L: -guluronic acids. Distribution of these monomers in the alginate structure is one of the important characteristics that affect the commercial value of the polymer. In the present work, the effect of agitation speed in the range of 200-700 rpm on alginate production by Azotobacter vinelandii ATCC(®) 9046 was investigated at a dissolved oxygen tension of 5% of air saturation. Experiments were conducted in a fermentor operated in batch mode for 72 h while the production of biomass and alginate, the consumption of substrate and the change in culture broth viscosity and monomer distribution of the polymer were monitored. Results showed that the growth rate of the bacteria increased from 0.165 to 0.239 h(-1) by the increase of mixing speed from 200 to 400 rpm. On the other hand, alginate production was found to be the most efficient at 400 rpm with the highest value of 4.51 g/l achieved at the end of fermentation. The viscosity of culture broth showed similar trends to alginate production. Viscosity was recorded as 24.61 cP at 400 rpm while it was only 4.26 cP at 700 rpm. The MM- and GG-block contents were almost equal in most of the culture times at 400 rpm. On the other hand, GG-blocks dominated at both low and high mixing speeds. Knowing that GG-blocks make rigid and protective gels with divalent cations, due to the higher GG-block content, the gel formation potential is higher at 200 rpm as well at 700 rpm, which might originate from the unfavorable environmental conditions that the bacteria were exposed to. PMID:22009058

  10. Towards antimicrobial yet bioactive Cu-alginate hydrogels.

    Science.gov (United States)

    Madzovska-Malagurski, I; Vukasinovic-Sekulic, M; Kostic, D; Levic, S

    2016-06-15

    The simplest approach to enhance alginate hydrogel characteristics and functional properties is to replace the calcium in the process of alginate gelation with other metallic ions which are essential for living systems. Gelling of alginate with other ions and using modern encapsulation techniques can provide new delivery systems with required properties. Hence, in this study Cu-alginate hydrogels in the form of microbeads were produced by electrostatic extrusion using gelling solutions with Cu(II) concentrations in the range 13.5-270 mM and comprehensively characterized in vitro. The variation of gelling solution concentration influenced the microbead Cu(II) content, size, biomechanical properties, Cu(II) release and subsequently potential biomedical application. The formulations chosen for biomedical evaluation showed potential for antimicrobial and tissue engineering applications. Microbeads with higher Cu(II) loading (~100 μmol g(-1)) induced immediate bactericidal effects against Escherichia coli and Staphylococcus aureus. Conversely, Cu(II) release from microbeads with the Cu(II) content of ~60 μmol g(-1) was slower and they were suitable for promoting and maintaining chondrogenic phenotype of bovine calf chondrocytes in 3D culture. Results of this study have shown possibilities for tuning Cu-alginate properties for potential biomedical applications such as antimicrobial wound dressings, tissue engineering scaffolds or articular cartilage implants.

  11. 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.

  12. Gelation and biocompatibility of injectable alginate-calcium phosphate gels for bone regeneration.

    Science.gov (United States)

    Cardoso, D Alves; van den Beucken, J J J P; Both, L L H; Bender, J; Jansen, J A; Leeuwenburgh, S C G

    2014-03-01

    An emerging approach toward development of injectable, self-setting, and fully biodegradable bone substitutes involves the combination of injectable hydrogel matrices with a dispersed phase consisting of nanosized calcium phosphate particles. Here, novel injectable composites for bone regeneration have been developed based on the combination of ultrapure alginate as the matrix phase, crystalline CaP [monetite and poorly crystalline hydroxyapatite (HA)] powders as both a dispersed mineral phase and a source of calcium for cross-linking alginate, glucono-delta-lactone (GDL) as acidifier and glycerol as both plasticizer and temporary sequestrant. The composites were maximized with respect to CaP content to obtain the highest amount of osteoconductive filler. The viscoelastic and physicochemical properties of the precursor compounds and composites were analyzed using rheometry, elemental analysis (for calcium release and uptake), acidity [by measuring pH in simulated body fluid (SBF)], general biocompatibility (subcutaneous implantation in rabbits), and osteocompatibility (implantation in femoral condyle bone defect of rabbits). The gelation of the resulting composites could be controlled from seconds to tens of minutes by varying the solubility of the CaP phase (HA vs. monetite) or amount of GDL. All composites mineralized extensively in SBF for up to 11 days. In vivo, the composites also disintegrated upon implantation in subcutaneous or bone tissue, leaving behind less degradable but osteoconductive CaP particles. Although the composites need to be optimized with respect to the available amount of calcium for cross-linking of alginate, the beneficial bone response as observed in the in vivo studies render these gels promising for minimally invasive applications as bone-filling material.

  13. Removal of textile dyes with biopolymers xanthan and alginic acid

    Energy Technology Data Exchange (ETDEWEB)

    Lozano-Alvarez, J.; Jauregui-Rincon, J.; Mendoza-Diaz, G.; Rodriguez-Vazquez, G.; Frausto-Reyes, C.

    2009-07-01

    Textile industry is an important activity that provides considerable benefits to people, but unfortunately dyeing of yarn and cloth produces pollution of water, a resource that is valuable and scarce. Dyeing of textiles fibers is an inefficient process, in view of the fact that approximately ten percent of total dye is thrown to municipal sewage. Although different treatment systems are applied to wastewater, dyes are resistant to physical, chemical and biological factors because of the way they are designed. (Author)

  14. Removal of textile dyes with biopolymers xanthan and alginic acid

    International Nuclear Information System (INIS)

    Textile industry is an important activity that provides considerable benefits to people, but unfortunately dyeing of yarn and cloth produces pollution of water, a resource that is valuable and scarce. Dyeing of textiles fibers is an inefficient process, in view of the fact that approximately ten percent of total dye is thrown to municipal sewage. Although different treatment systems are applied to wastewater, dyes are resistant to physical, chemical and biological factors because of the way they are designed. (Author)

  15. Effects of ambroxol on alginate of mature Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Li, Fang; Yu, Jialin; Yang, Hua; Wan, Zhenyan; Bai, Dan

    2008-07-01

    Biofilm-forming bacteria Pseudomonas aeruginosa is a common pathogen in mechanically ventilated newborns, which can cause life-threatening infections. Alginate of mucoid Pseudomonas aeruginosa biofilms is considered an important virulence factor which contributes to the resistance to antibiotics. Traditionally, ambroxol is widely used in newborns with lung problems as a mucolytic agent and antioxidant agent as well. And there are few studies that demonstrated the anti-biofilm activity of ambroxol. In this study, we found that ambroxol can affect the structure of mucoid Pseudomonas aeruginosa biofilms. Further, we found that ambroxol reduces the production of alginate, the expression of the important genes and the activity of key enzyme guanosine diphospho-D-mannose dehydrogenase (GDP-mannose dehydrogenase; GMD) which were involved in alginate biosynthesis.

  16. 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.

  17. 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.

  18. 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.

  19. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

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

    2001-01-01

    -resistant communities of microorganisms organized in biofilms. Although biofilm formation and the conversion to mucoidy are both important aspects of CF pathogenesis, the relationship between them is at the present unclear. In this study, we report that the overproduction of alginate affects biofilm development...... on an 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....

  20. Preparation of porcine hemoglobin microcapsules of chitosan-sodium alginate

    Institute of Scientific and Technical Information of China (English)

    LI Jun; ZHANG Jijuan; ZHAO Xinjuan; YU Yan

    2007-01-01

    Using an emulsification-gelation method,chitosansodium alginate-porcine hemoglobin microcapsules were prepared.Results show that these microcapsules have better forms and small granules with 1 μm size of the mean particle size.They possess a relatively narrow and normal Gaussian distribution.The loading efficiency of porcine hemoglobin (pHb) in microcapsules is more than 90%.The pHb released from microcapsules is extended for more than one month.Chitosan-sodium alginate-hemoglobin microcapsules are expected to become an artificial oxygen-carrying therapeutic agent with sustained release for intravenous injection.

  1. HPMC-based gastroretentive dual working matrices coated with Ca(+2) ion crosslinked alginate-fenugreek gum gel membrane.

    Science.gov (United States)

    Bera, Hriday; Gaini, Chakravarthy; Kumar, Sanoj; Sarkar, Srimanta; Boddupalli, Shashank; Ippagunta, Sohitha Reddy

    2016-10-01

    Novel alginate-fenugreek gum (FG) gel membrane coated hydroxypropylmethylcellulose (HPMC) based matrix tablets were developed for intragastric quetiapine fumarate (QF) delivery by combining floating and swelling mechanisms. The effects of polymer blend ratios [HPMC K4M:HPMC E15] and citric acid contents on time taken for 50% drug release (t50%, min) and drug release at 8h (Q8h, %) were studied to optimize the core tablets by 3(2) factorial design. The optimized tablets (F-O) exhibited t50% of 247.67±3.51min and Q8h of 71.11±0.32% with minimum errors in prediction. The optimized tablets were coated with Ca(+2) ions crosslinked alginate-FG gel membrane by diffusion-controlled interfacial complexation technique. The biopolymeric-coated optimized matrices exhibited superior buoyancy, preferred swelling characteristics and slower drug release rate. The drug release profiles of the QF-loaded uncoated and coated optimized matrices were best fitted in Korsmeyer-Peppas model with anomalous diffusion driven mechanism. The uncoated and coated tablets containing QF were also characterized for drug-excipients compatibility, thermal behaviour and surface morphology by FTIR, DSC and SEM analyses, respectively. Thus, the newly developed alginate-FG gel membrane coated HPMC matrices are appropriate for intragastric delivery of QF over a prolonged period of time with greater therapeutic benefits. PMID:27287111

  2. HPMC-based gastroretentive dual working matrices coated with Ca(+2) ion crosslinked alginate-fenugreek gum gel membrane.

    Science.gov (United States)

    Bera, Hriday; Gaini, Chakravarthy; Kumar, Sanoj; Sarkar, Srimanta; Boddupalli, Shashank; Ippagunta, Sohitha Reddy

    2016-10-01

    Novel alginate-fenugreek gum (FG) gel membrane coated hydroxypropylmethylcellulose (HPMC) based matrix tablets were developed for intragastric quetiapine fumarate (QF) delivery by combining floating and swelling mechanisms. The effects of polymer blend ratios [HPMC K4M:HPMC E15] and citric acid contents on time taken for 50% drug release (t50%, min) and drug release at 8h (Q8h, %) were studied to optimize the core tablets by 3(2) factorial design. The optimized tablets (F-O) exhibited t50% of 247.67±3.51min and Q8h of 71.11±0.32% with minimum errors in prediction. The optimized tablets were coated with Ca(+2) ions crosslinked alginate-FG gel membrane by diffusion-controlled interfacial complexation technique. The biopolymeric-coated optimized matrices exhibited superior buoyancy, preferred swelling characteristics and slower drug release rate. The drug release profiles of the QF-loaded uncoated and coated optimized matrices were best fitted in Korsmeyer-Peppas model with anomalous diffusion driven mechanism. The uncoated and coated tablets containing QF were also characterized for drug-excipients compatibility, thermal behaviour and surface morphology by FTIR, DSC and SEM analyses, respectively. Thus, the newly developed alginate-FG gel membrane coated HPMC matrices are appropriate for intragastric delivery of QF over a prolonged period of time with greater therapeutic benefits.

  3. Calcium alginate gels as stem cell matrix-making paracrine stem cell activity available for enhanced healing after surgery.

    Directory of Open Access Journals (Sweden)

    Andreas Schmitt

    Full Text Available Regeneration after surgery can be improved by the administration of anabolic growth factors. However, to locally maintain these factors at the site of regeneration is problematic. The aim of this study was to develop a matrix system containing human mesenchymal stem cells (MSCs which can be applied to the surgical site and allows the secretion of endogenous healing factors from the cells. Calcium alginate gels were prepared by a combination of internal and external gelation. The gelling behaviour, mechanical stability, surface adhesive properties and injectability of the gels were investigated. The permeability of the gels for growth factors was analysed using bovine serum albumin and lysozyme as model proteins. Human MSCs were isolated, cultivated and seeded into the alginate gels. Cell viability was determined by AlamarBlue assay and fluorescence microscopy. The release of human VEGF and bFGF from the cells was determined using an enzyme-linked immunoassay. Gels with sufficient mechanical properties were prepared which remained injectable through a syringe and solidified in a sufficient time frame after application. Surface adhesion was improved by the addition of polyethylene glycol 300,000 and hyaluronic acid. Humans MSCs remained viable for the duration of 6 weeks within the gels. Human VEGF and bFGF was found in quantifiable concentrations in cell culture supernatants of gels loaded with MSCs and incubated for a period of 6 weeks. This work shows that calcium alginate gels can function as immobilization matrices for human MSCs.

  4. PENGARUH UKURAN PARTIKEL DAN PROPORSI GULURONAT/MANURONAT DALAM ALGINAT TERHADAP SIFAT DAN SENSORIS PRODUK HASIL RESTRUKTURISASI DARI BUAH SIRSAK [The Influence of Particle size and Guluronic/Mannuronic Proportion of Alginate on Physical and Sensory Characteristics of Restructured Products from Soursop

    Directory of Open Access Journals (Sweden)

    Sri Raharjo

    2003-12-01

    Full Text Available The application of restructuring technology is intended to add value for local fruits. Fresh and ripe sour sop fruits are frequently of having defective appearance, irregular shape and size, or showing signs of insect infestation which make the whole fruit is less acceptable by consumers. Previous study has indicated that sour sop fruit can be restructured into a fresh fruit product with acceptable sensory characteristics using calcium alginate gel system. This particular study was intended to determine the effect of alginate powder particles size and its guluronic/mannuronic proportion on the physical and sensorial properties of restructured sour sop. The restructured fruit product was evaluated based on its gel strength, pH colour, and sensory attributes which include taste, aroma, mouth feel, appearance, and hardness. Sour sop restructured by internal setting with coarse alginate powder (36 mesh tend to have softer gel compared to the use of fine alginate powder (120 mesh. Different proportion of guluronic/mannuronic in the alginate used for the restructurization resulted in the same gel strength when calcium lactate powder was used. However, the use of encapsulated calcium lactate resulted in stronger gel with alginate containing higher proportion of mannuronic acid. The alginate particle size and proportion of guluronic/mannuronic content showed no significant difference in product colour and sensory attributes evaluated.

  5. 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

  6. Chitosan and alginate biopolymer membranes for remediation of contaminated water with herbicides.

    Science.gov (United States)

    Agostini de Moraes, Mariana; Cocenza, Daniela Sgarbi; da Cruz Vasconcellos, Fernando; Fraceto, Leonardo Fernandes; Beppu, Marisa Masumi

    2013-12-15

    This study investigated the adsorption behavior of the herbicides diquat, difenzoquat and clomazone on biopolymer membranes prepared with alginate and chitosan (pristine and multi-layer model) for contaminated water remediation applications. Herbicides, at concentrations ranging from 5 μM to 200 μM, were adsorbed in either pure alginate, pure chitosan or a bilayer membrane composed of chitosan/alginate. No adsorption of clomazone was observed on any of the membranes, probably due to lack of electrostatic interactions between the herbicide and the membranes. Diquat and difenzoquat were only adsorbed on the alginate and chitosan/alginate membranes, indicating that this adsorption takes place in the alginate layer. At a concentration of 50 μM, diquat adsorption reaches ca. 95% after 120 min on both the alginate and chitosan/alginate membranes. The adsorption of difenzoquat, at the same concentration, reaches ca. 62% after 120 min on pure alginate membranes and ca. 12% on chitosan/alginate bilayer membranes. The adsorption isotherms for diquat and difenzoquat were further evaluated using the isotherm models proposed by Langmuir and by Freundlich, where the latter represented the best-fit model. Results indicate that adsorption occurs via coulombic interactions between the herbicides and alginate and is strongly related to the electrostatic charge, partition coefficients and dissociation constants of the herbicides. Biopolymer based membranes present novel systems for the removal of herbicides from contaminated water sources and hold great promise in the field of environmental science and engineering.

  7. 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.

  8. Immobilization of coacervate microcapsules in multilayer sodium alginate beads for efficient oral anticancer drug delivery.

    Science.gov (United States)

    Feng, Chao; Song, Ruixi; Sun, Guohui; Kong, Ming; Bao, Zixian; Li, Yang; Cheng, Xiaojie; Cha, Dongsu; Park, Hyunjin; Chen, Xiguang

    2014-03-10

    We have designed and evaluated coacervate microcapsules-immobilized multilayer sodium alginate beads (CMs-M-ALG-Beads) for oral drug delivery. The CMs-M-ALG-Beads were prepared by immobilization of doxorubicin hydrochloride (DOX) loaded chitosan/carboxymethyl coacervate microcapsules (DOX:CS/CMCS-CMs) in the core and layers of the multilayer sodium alginate beads. The obtained CMs-M-ALG-beads exhibited layer-by-layer structure and rough surface with many nanoscale particles. The swelling characteristic and drug release results indicated that 4-layer CMs-M-ALG-Beads possessed favorable gastric acid tolerance (the swelling rate <5%, the cumulative drug release rate <3.8%). In small intestine, the intact DOX:CS/CMCS-CMs were able to rapidly release from CMs-M-ALG-Beads with the dissolution of ALG matrix. Ex vivo intestinal mucoadhesive and permeation showed that CMs-M-ALG-Beads exhibited continued growth for P(app) values of DOX, which was 1.07-1.15 folds and 1.28-1.38 folds higher than DOX:CS:CMCS-CMs in rat jejunum and ileum, respectively, demonstrating that CMs-M-ALG-Beads were able to enhance the absorption of DOX by controlled releasing DOX:CS/CMCS-CMs and prolonging the contact time between the DOX:CS/CMCS-CMs and small intestinal mucosa.

  9. Rapidly in situ forming biodegradable hydrogels by combining alginate and hydroxyapatite nanocrystal

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The in situ forming biodegradable polymer scaffolds are important biomaterials for tissue engineering and drug delivery.Hydrogels derived from natural proteins and polysaccharides are ideal tissue engineering scaffolds since they resemble the extracellular matrices of the tissue comprising various amino acids and sugar based macromolecules.This work presented an injectable system from partially oxidized alginate and hydroxyapatite(HAP) nanocrystal for tissue engineering and drug delivery applications.In situ release of calcium cations from HAP nanocrystal was adopted through lowering the pH with slow hydrolysis of D-glucono-δ-lactone(GDL) and homogeneous alginate gels were formulated as scaffolds with defined dimensions.The gelation time could be controlled to be in 10-15 min.The SEM observations confirmed the porous 3D hydrogel structure with interconnected pores ranging from 20 to 300 μm and the HAP particles dispersed in the scaffolds uniformly.The potential applications such as tissue engineering scaffold and injectable drug delivery system were demonstrated by subcutaneous implant test in test rats.

  10. Rheological behavior and Ibuprofen delivery applications of pH responsive composite alginate hydrogels.

    Science.gov (United States)

    Jabeen, Suraya; Maswal, Masrat; Chat, Oyais Ahmad; Rather, Ghulam Mohammad; Dar, Aijaz Ahmad

    2016-03-01

    Synthesis and structural characterization of hydrogels composed of sodium alginate, polyethylene oxide and acrylic acid with cyclodextrin as the hydrocolloid prepared at different pH values is presented. The hydrogels synthesized show significant variations in rheological properties, drug encapsulation capability and release kinetics. The hydrogels prepared at lower pH (pH 1) are more elastic, have high tensile strength and remain almost unaffected by varying temperature or frequency. Further, their Ibuprofen encapsulation capacity is low and releases it slowly. The hydrogel prepared at neutral pH (pH 7) is viscoelastic, thermo-reversible and also exhibits sol-gel transition on applying frequency and changing temperature. It shows highest Ibuprofen encapsulation capacity and also optimum drug release kinetics. The hydrogel prepared at higher pH (pH 12) is more viscous, has low tensile strength, is unstable to change in temperature and has fast drug release rate. The study highlights the pH responsiveness of three composite alginate hydrogels prepared under different conditions to be employed in drug delivery applications. PMID:26717508

  11. 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...

  12. 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.

  13. Factors affecting protein release from alginate-chitosan coacervate microcapsules during production and gastric/intestinal simulation.

    Science.gov (United States)

    Vandenberg, G W; Drolet, C; Scott, S L; de la Noüe, J

    2001-12-13

    A series of experiments was performed to evaluate the influence of a number of physico-chemical factors on the diffusion of a model protein, bovine serum albumin (BSA), from dried chitosan-coated alginate microcapsules. Diffusion of BSA was quantified during the microcapsule manufacture processes (gelation, washing, rinsing) and during incubation in conditions simulating the pH encountered during the gastric (0.1 N HCl; pH 1.5) and intestinal (200 mM Tris-HCl; pH 7.5) phases of digestion. Factors tested included alginate and chitosan concentration, calcium chloride (CaCl2) concentration in the gelation medium, loading rate, chitosan molecular mass and pH of the gelation medium. Microcapsule size and gelation time were altered in order to determine their effects on protein retention. Alginate and chitosan concentration significantly influenced BSA retention during microcapsule manufacture and acid incubation, as did calcium chloride concentration in the gelation medium (P<0.05). BSA retention during manufacture was not significantly altered by protein loading rate or pH of the encapsulation medium, however, protein retention during acid incubation decreased significantly with increasing protein loading rate and encapsulation medium pH (P<0.05). Microcapsules that were washed with acetone following manufacture demonstrated significantly increased protein retention during acid incubation (P<0.05). In microcapsules that had been acetone-dried to a point whereby their mass was reduced to 10% of that immediately following encapsulation, protein retention was over 80% following 24-h acid incubation vs. only 20% protein retention from non acetone-dried microcapsules. The presence of calcium in the neutral buffer medium significantly reduced BSA diffusion in a concentration-dependent manner (P<0.05).

  14. Will the use of double barrier result in sustained release of vancomycin? Optimization of parameters for preparation of a new antibacterial alginate-based modern dressing.

    Science.gov (United States)

    Kurczewska, Joanna; Sawicka, Paulina; Ratajczak, Magdalena; Gajęcka, Marzena; Schroeder, Grzegorz

    2015-12-30

    The aim of this research was to prepare and characterize an alginate-based wound dressing containing vancomycin immobilized at the silica surface. The silica samples functionalized with amine, diol and carboxylic acid groups were loaded with 7.8, 5.7 and 7.1wt.% of the antibiotic respectively. The immobilized drug was encapsulated in alginate or gelatin/alginate gels and the average concentration of vancomycin was about 10mg per g of the dried gel. The effect of functional organic groups at the silica surface on the release rate of the drug was investigated. Only the drug immobilized at Si-amine in alginate matrix was found to demonstrate slower release from the proposed wound dressing. The in vitro release profiles for other silica carriers did not show significant differences in relation to the free loaded drug. The presence of gelatin had a favourable impact on the slowing down of the drug release from the dressing with a double barrier. All the gels studied with vancomycin immobilized at the silica surface demonstrated antimicrobial activity against various bacteria. A reduction of the drug dose to a half had no effect on changing microbiological activity of gels.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. Alginate hydrogels coated with chitosan for wound dressing.

    Science.gov (United States)

    Straccia, Maria Cristina; d'Ayala, Giovanna Gomez; Romano, Ida; Oliva, Adriana; Laurienzo, Paola

    2015-05-11

    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.

  20. Serum albumin-alginate coated beads: mechanical properties and stability.

    Science.gov (United States)

    Edwards-Lévy, F; Lévy, M C

    1999-11-01

    According to a previously described method, alginate beads were prepared from a Na-alginate solution containing propylene glycol alginate (PGA) and human serum albumin (HSA). The solution was added dropwise to a CaCl2 solution. The beads were treated with NaOH, which started the formation of amide bonds between HSA and PGA at the periphery, giving a membrane. Batches of beads with increasingly thick membranes were prepared using growing concentrations of NaOH, and studied with a texture analyser. When raising NaOH concentration, the rupture strength progressively increased, and the resistance strength to a deformation of 50% of total height also increased before slightly decreasing for the highest NaOH concentration. Variations of bead elasticity were also observed. When the beads were prepared with saline reducing gelation time from 10 to 5 min, and reaction time from 15 to 5 min, mechanical properties varied more progressively with the NaOH concentration, while the results became more reproducible. A series of assays conducted with 0.01 M NaOH confirmed the importance of using a short gelation time, and saline rather than water. Stability assays were also performed. The results were compared to those of alginate-polylysine coated beads and showed the interest of the transacylation method. PMID:10535819

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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....

  6. 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...

  7. 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...

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. A BOD monitoring disposable reactor with alginate-entrapped bacteria.

    Science.gov (United States)

    Villalobos, Patricio; Acevedo, Cristian A; Albornoz, Fernando; Sánchez, Elizabeth; Valdés, Erika; Galindo, Raúl; Young, Manuel E

    2010-10-01

    Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen that is required for the biochemical oxidation of the organic compounds in 5 days. New biosensor-based methods have been conducted for a faster determination of BOD. In this study, a mathematical model to evaluate the feasibility of using a BOD sensor, based on disposable alginate-entrapped bacteria, for monitoring BOD in situ was applied. The model considers the influences of alginate bead size and bacterial concentration. The disposable biosensor can be adapted according to specific requirements depending on the organic load contained in the wastewater. Using Klein and Washausen parameter in a Lineweaver-Burk plot, the glucose diffusivity was calculated in 6.4 × 10(-10) (m2/s) for beads of 1 mm in diameter and slight diffusion restrictions were observed (n = 0.85). Experimental results showed a correlation (p BOD test. The biosensor response was representative of BOD.

  14. 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.

  15. 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

  16. 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...

  17. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants.

  18. Evaluation of an alginate-gelatine crosslinked hydrogel for bioplotting.

    Science.gov (United States)

    Zehnder, Tobias; Sarker, Bapi; Boccaccini, Aldo R; Detsch, Rainer

    2015-04-08

    Using additive manufacturing to create hydrogel scaffolds which incorporate homogeneously distributed, immobilized cells in the context of biofabrication approaches represents an emerging and expanding field in tissue engineering. Applying hydrogels for additive manufacturing must consider the material processing properties as well as their influence on the immobilized cells. In this work alginate-dialdehyde (ADA), a partially oxidized alginate, was used as a basic material to improve the physico-chemical properties of the hydrogel for cell immobilization. At first, the processing ability of the gel using a bioplotter and the compatibility of the process with MG-63 osteoblast like cells were investigated. The metabolic and mitochondrial activities increased at the beginning of the incubation period and they balanced at a relatively high level after 14-28 days of incubation. During this incubation period the release of vascular endothelial growth factor-A also increased. After 28 days of incubation the cell morphology showed a spreading morphology and cells were seen to move out of the scaffold struts covering the whole scaffold structure. The reproducible processing capability of alginate-gelatine (ADA-GEL) and the compatibility with MG-63 cells were proven, thus the ADA-GEL material is highlighted as a promising matrix for applications in biofabrication.

  19. 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.

  20. 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

  1. Single molecule investigation of the onset and minimum size of the calcium-mediated junction zone in alginate.

    Science.gov (United States)

    Bowman, Kate A; Aarstad, Olav Andreas; Nakamura, Marcela; Stokke, Bjørn Torger; Skjåk-Bræk, Gudmund; Round, Andrew N

    2016-09-01

    One of the principal roles of alginate, both natively and in commercial applications, is gelation via Ca(2+)-mediated crosslinks between blocks of guluronic acid. In this work, single molecule measurements were carried out between well-characterised series of nearly monodisperse guluronic acid blocks ('oligoGs') using dynamic force spectroscopy. The measurements provide evidence that for interaction times on the order of tens of milliseconds the maximum crosslink strength is achieved by pairs of oligoGs long enough to allow the coordination of 4Ca(2+) ions, with both shorter and longer oligomers forming weaker links. Extending the interaction time from tens to hundreds of milliseconds allows longer oligoGs to achieve much stronger crosslinks but does not change the strength of individual links between shorter oligoGs. These results are considered in light of extant models for the onset of cooperative crosslinking in polyelectrolytes and an anisotropic distribution of oligoGs on interacting surfaces and provide a timescale for the formation and relaxation of alginate gels at the single crosslink level. PMID:27185115

  2. Development of a sodium alginate-based organic/inorganic superabsorbent composite hydrogel for adsorption of methylene blue.

    Science.gov (United States)

    Thakur, Sourbh; Pandey, Sadanand; Arotiba, Omotayo A

    2016-11-20

    Batch adsorption experiments were carried out for the removal of methylene blue (MB) cationic dye from aqueous solution using organic/inorganic hydrogel nanocomposite of titania incorporated sodium alginate crosslinked polyacrylic acid (SA-cl-poly(AA)-TiO2). The hydrogel was prepared by graft copolymerization of acrylic acid (AA) onto sodium alginate (SA) biopolymer in the presence of a crosslinking agent, a free radical initiator and TiO2 nanoparticles. The hydrogel exhibited a high swelling capacity of 412.98g/g. The factors influencing adsorption capacity of the absorbents such as pH of the dye solutions, initial concentration of the dye, amount of absorbents, and temperature were investigated and used to propose a possible mechanism of adsorption. The adsorption process concurs with a pseudo-second-order kinetics and with Langmuir isotherm equation. A very high adsorption capacity (Qmax=2257.36 (mg/g)) and a correlation coefficient of 0.998 calculated from isotherm equations show the high efficiency of the absorbent and thus expected to be a good candidate as an absorbent for water treatment. PMID:27561469

  3. 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.

  4. 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

  5. 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.

  6. Encapsulation in alginate and alginate coated-chitosan improved the survival of newly probiotic in oxgall and gastric juice.

    Science.gov (United States)

    Trabelsi, Imen; Bejar, Wacim; Ayadi, Dorra; Chouayekh, Hichem; Kammoun, Radhouane; Bejar, Samir; Ben Salah, Riadh

    2013-10-01

    This study was undertaken to develop an optimum composition model for the microencapsulation of a newly probiotic on sodium alginate using response surface methodology. The individual and interactive effects of three independent variables, namely sodium alginate concentration, biomass concentration, and hardening time, were investigated using Box-Behnken design experiments. A second ordered polynomial model was fitted and optimum conditions were estimated. The optimal conditions identified were 2% for sodium alginate, 10(10)UFC/ml for biomass, and 30 min for hardening time. The experimental value obtained for immobilized cells under these conditions was about 80.98%, which was in close agreement with the predicted value of 82.6%. Viability of microspheres (96%) was enhanced with chitosan as coating materials. The survival rates of free and microencapsulated Lactobacillus plantarum TN8 during exposure to artificial gastrointestinal conditions were compared. The results revealed that the encapsulated cells exhibited significantly higher resistances to artificial intestinal juice (AIJ) and artificial gastric juice (AGJ). Microencapsulation was also noted to effectively protect the strain from heating at 65 °C and refrigerating at 4 °C. Taken together, the findings indicated that microencapsulation conferred important protective effects to L. plantarum against the gastrointestinal conditions encountered during the transit of food.

  7. Preparation of N,O-carboxymethyl chitosan coated alginate microcapsules and their application to Bifidobacterium longum BIOMA 5920

    International Nuclear Information System (INIS)

    In order to greatly improve vitality of probiotic bacteria within the application, a novel biocompatible vehicle, N,O-carboxymethyl chitosan (NOCs) with appropriate degrees of substitution coat alginate (ALg) microparticles, was prepared by electrostatic droplet generation. The amount of chitosan (Cs) and N,O-carboxymethyl chitosan (NOCs) coated on the ALg microparticles was determined by differential scanning calorimetry. The surface morphology of ALg microparticles, Cs coated ALg microparticles and NOCs coated ALg microparticles was determined using scanning electron microscopy. The coating thickness of Cs coated ALg microparticles and that of NOCs coated ALg microparticles was directly observed with confocal laser scanning microscopy. In order to assess pH sensitivity of microparticles, the bovine serum albumin release from the microspheres was tested in acid solution (pH 2.0) for 2 h and subsequently in alkaline solution (pH 7.0) for 2 h. The survival of Bifidobacterium longum BIOMA 5920 loaded in NOCs coated with ALg microparticle was improved in simulated gastric juice (pH 2.0, for 2 h) compared to that of B. longum BIOMA 5920 loaded in ALg microparticles and Cs coated ALg microparticles. After incubation in simulated intestinal juices (pH 7.0, 2 h), the release of microencapsulated B. longum BIOMA 5920 was investigated. - Highlights: • Synthesised N,O-carboxymethyl chitosan (NOCs) coated alginate (ALg) microspheres. • Their effect on intestinal microflora was investigated in simulated gastric juices. • NOCs A coated ALg microspheres improved Bifidobacterium longum survival in SGJ. • The modified chitosan layer improved the pH-response of alginate microspheres. • NOCs A coated microspheres could be used to deliver oral bioactive compounds

  8. Preparation of N,O-carboxymethyl chitosan coated alginate microcapsules and their application to Bifidobacterium longum BIOMA 5920

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Yu; Su, Ran [Shaanxi R and D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University (China); Fan, Dai-Di, E-mail: fandaidi@nwu.edu.cn [Shaanxi R and D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University (China); Zhu, Xiao-Li [Shaanxi R and D Center of Biomaterials and Fermentation Engineering, School of Urban and Environmental Science, Northwest University, Taibai North Road 229, Xi' an, Shaanxi 710069 (China); Zhang, Wen-Ni [Shaanxi R and D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University (China); Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering, Northwest University (China)

    2013-07-01

    In order to greatly improve vitality of probiotic bacteria within the application, a novel biocompatible vehicle, N,O-carboxymethyl chitosan (NOCs) with appropriate degrees of substitution coat alginate (ALg) microparticles, was prepared by electrostatic droplet generation. The amount of chitosan (Cs) and N,O-carboxymethyl chitosan (NOCs) coated on the ALg microparticles was determined by differential scanning calorimetry. The surface morphology of ALg microparticles, Cs coated ALg microparticles and NOCs coated ALg microparticles was determined using scanning electron microscopy. The coating thickness of Cs coated ALg microparticles and that of NOCs coated ALg microparticles was directly observed with confocal laser scanning microscopy. In order to assess pH sensitivity of microparticles, the bovine serum albumin release from the microspheres was tested in acid solution (pH 2.0) for 2 h and subsequently in alkaline solution (pH 7.0) for 2 h. The survival of Bifidobacterium longum BIOMA 5920 loaded in NOCs coated with ALg microparticle was improved in simulated gastric juice (pH 2.0, for 2 h) compared to that of B. longum BIOMA 5920 loaded in ALg microparticles and Cs coated ALg microparticles. After incubation in simulated intestinal juices (pH 7.0, 2 h), the release of microencapsulated B. longum BIOMA 5920 was investigated. - Highlights: • Synthesised N,O-carboxymethyl chitosan (NOCs) coated alginate (ALg) microspheres. • Their effect on intestinal microflora was investigated in simulated gastric juices. • NOCs A coated ALg microspheres improved Bifidobacterium longum survival in SGJ. • The modified chitosan layer improved the pH-response of alginate microspheres. • NOCs A coated microspheres could be used to deliver oral bioactive compounds.

  9. Extraction of alginate from Sargassum muticum: process optimization and study of its functional activities

    DEFF Research Database (Denmark)

    Mazumder, Anupriya; Holdt, Susan Løvstad; De Francisci, Davide;

    2016-01-01

    % ethanol. A second order polynomial equation using multiple regression analysis was developed, and the predicted extraction yield showed a high coefficient of determination (R 2 = 0.98) with the experimental alginate yield. The functionality of extracted alginate and residual supernatant left over after...

  10. 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

  11. Considerations in binding diblock copolymers on hydrophilic alginate beads for providing an immunoprotective membrane

    NARCIS (Netherlands)

    Spasojevic, Milica; Bhujbal, Swapnil; Paredes, Genaro; de Haan, Bart J.; Schouten, Arend J.; de Vos, Paul

    2014-01-01

    Alginate-based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab-to-lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock p

  12. 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

  13. 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.

  14. Adsorption of human immunoglobulin to implantable alginate-poly-L-lysine microcapsules : Effect of microcapsule composition

    NARCIS (Netherlands)

    Tam, Susan K.; de Haan, Bart J.; Faas, Marijke M.; Halle, Jean-Pierre; Yahia, L'Hocine; de Vos, Paul

    2009-01-01

    Alginate-poly-L-lysine-alginate (APA) microcapsules continue to be the most widely Studied device for the immuno-protection of transplanted therapeutic cells. Producing APA microcapsules having a reproducible and high level of biocompatibility requires an understanding of the mechanisms of the immun

  15. 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

    on 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 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, increased viscosity...

  16. 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.

  17. Alginate-polymethacrylate hybrid hydrogels with double ionic and covalent network for tissue engineering

    Science.gov (United States)

    Schizzi, I.; Utzeri, R.; Castellano, M.; Stagnaro, P.

    2016-05-01

    Hydrogels based on alginates are very promising candidates to realize scaffolds for tissue engineering. Indeed, alginate hydrogels are able to mimic the extracellular matrix (ECM) thus promoting in vitro and/or in vivo cell growth; moreover, their capability of giving rise to highly porous structures can specifically favor the osteochondral tissue regeneration. However, mechanical properties of polymeric hydrogels are often inadequate to endow the final constructs with the required characteristics of elasticity and toughness. Here alginate/polymethacrylate hybrid hydrogels, with a suitable porous structure and characterized by a double network, ionic (from alginate) and covalent (from polymethacrylate) were designed and realized. The mechanical performance of these hybrid materials resulted, as expected, improved due to the double interconnected network, where the alginate portion provides the appropriate micro-environment mimicking the ECM, whereas the polymethacrylate portion acts as a reinforce.

  18. 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.

  19. Removal of some divalent cations from water by membrane-filtration assisted with alginate.

    Science.gov (United States)

    Fatin-Rouge, Nicolas; Dupont, Alexandra; Vidonne, Alain; Dejeu, Jérome; Fievet, Patrick; Foissy, Alain

    2006-03-01

    The removal of divalent metal ions from hard waters or galvanic wastewater by polymer-assisted membrane filtration using alginate was investigated. The ability of this natural polymer to form aggregates and gels in presence of metal ions was studied, in order to carry out metal removal by ultra or micro-filtration. Alginate titrations have shown the presence of amine groups in addition to carboxylates onto the polymer backbone. The binding properties of alginate with divalent cations have been studied, showing an increasing affinity for Ca2+ over Mg2+ as polymer concentration increases, and the relative affinity Pb2+ > or = Cu2+ > Zn2+ > Ni2+. The softening of hard natural waters was achieved successfully and easily, but needs an optimal alginate concentration approximately 4 x 10(-2) M. The alginate powder can be directly added to hard waters. Except for Ni2+, metal-removal was efficient. Polymer regeneration has shown that Cu2+-complexes are labiles.

  20. Absorption Ability of Different M/G Values of Alginate Fiber

    Institute of Scientific and Technical Information of China (English)

    GUO Xiao-qing; ZHU Ping

    2007-01-01

    The M/G values of different sodium alginate were studied by means of 1H-NMR. The alginate fiber was prepared via wet-spinning technology. The effects of M/G,the concentration of sodium-alginate, the concentration of the coagulation bath and coagulating time on the absorptive ability of alginate fiber were discussed. The results show that the absorptive ability to different substances varies in such order: physiological saline> blood > tap water > distilled water. The absorptive ability of the alginate fiber increases with the increase of M/G value and the concentration of sodium-aiginate. Gradually increasing the conceatration of coagulation bath, it increases until the concentration is up to 5%. However,it reduces with lasting coagulating time.

  1. 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.

  2. 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

  3. 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)

  4. 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

  5. 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*).

  6. 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.

  7. The effect on lactic fermentation of concentrating inert material with immobilised cells in a calcium alginate biocatalyser

    Directory of Open Access Journals (Sweden)

    Juan Carlos Serrato

    2010-04-01

    Full Text Available Colombia is one of the world’s main sugarcane cultivating countries but it has not diversified its fermentation industry; a few fermentation industries produce alcohol and yeasts. Lactic acid and its derivatives then become alternatives providing added value to the sugar produced, thus benefiting the regions producing the sugar.This work evaluated the kinetics of lactic acid production using immobilised cells in calcium alginate at different concentrations of inert material. Lactobacillus delbrueckiI was the microorganism used and fermentation broth mainly consisted of sucrose and yeast exact. CSTR reactors were used without pH control. The results suggested that 2% to 3% inert material in the biocatalyst increased cellular retention and diffusiveness, leading to improved conversion and reaction rate.

  8. Interplay between flow and diffusion in capillary alginate hydrogels.

    Science.gov (United States)

    Schuster, Erich; Sott, Kristin; Ström, Anna; Altskär, Annika; Smisdom, Nick; Gebäck, Tobias; Lorén, Niklas; Hermansson, Anne-Marie

    2016-05-01

    Alginate gels with naturally occurring macroscopic capillaries have been used as a model system to study the interplay between laminar flow and diffusion of nanometer-sized solutes in real time. Calcium alginate gels that contain homogeneously distributed parallel-aligned capillary structures were formed by external addition of crosslinking ions to an alginate sol. The effects of different flow rates (0, 1, 10, 50 and 100 μl min(-1)) and three different probes (fluorescein, 10 kDa and 500 kDa fluorescein isothiocyanate-dextran) on the diffusion rates of the solutes across the capillary wall and in the bulk gel in between the capillaries were investigated using confocal laser scanning microscopy. The flow in the capillaries was produced using a syringe pump that was connected to the capillaries via a tube. Transmission electron microscopy revealed an open aggregated structure close to the capillary wall, followed by an aligned network layer and the isotropic network of the bulk gel. The most pronounced effect was observed for the 1 nm-diameter fluorescein probe, for which an increase in flow rate increased the mobility of the probe in the gel. Fluorescence recovery after photobleaching confirmed increased mobility close to the channel, with increasing flow rate. Mobility maps derived using raster image correlation spectroscopy showed that the layer with the lowest mobility corresponded to the anisotropic layer of ordered network chains. The combination of microscopy techniques used in the present study elucidates the flow and diffusion behaviors visually, qualitatively and quantitatively, and represents a promising tool for future studies of mass transport in non-equilibrium systems.

  9. Effect of sodium alginate coating enriched with horsemint (Mentha longifolia) essential oil on the quality of bighead carp fillets during storage at 4°C.

    Science.gov (United States)

    Heydari, Ramin; Bavandi, Shahmir; Javadian, Seyed Roholla

    2015-05-01

    Effect of sodium alginate coating enriched with horsemint essential oil (HEO) on the quality of bighead carp (Aristichthys nobilis) fillets at refrigeration temperature (4 ± 1°C) was studied. Bighead carp fillets were coated with neat sodium alginate (SA) and sodium alginate containing 0.5 and 1% v/v of HEO and their quality changes in terms of total volatile basic nitrogen (TVB-N), peroxide value (PV), thiobarbituric acid (TBA), and microbial counts were investigated. SA coating enriched with the essential oil could reduce the spoilage of the fillets and extend their shelf-life. Samples treated with SA-containing HEO showed significantly (P < 0.05) lower TVB-N content and lipid oxidation, as reflected by lower PV, FFA and TBA values during the storage period compared with the SA and control. The treatment also reduced the degree of microbial deterioration of the fillets (about 1.5 log10 CFU/g) more efficiently than the SA. PMID:25987993

  10. Effect of sodium alginate coating enriched with horsemint (Mentha longifolia) essential oil on the quality of bighead carp fillets during storage at 4°C.

    Science.gov (United States)

    Heydari, Ramin; Bavandi, Shahmir; Javadian, Seyed Roholla

    2015-05-01

    Effect of sodium alginate coating enriched with horsemint essential oil (HEO) on the quality of bighead carp (Aristichthys nobilis) fillets at refrigeration temperature (4 ± 1°C) was studied. Bighead carp fillets were coated with neat sodium alginate (SA) and sodium alginate containing 0.5 and 1% v/v of HEO and their quality changes in terms of total volatile basic nitrogen (TVB-N), peroxide value (PV), thiobarbituric acid (TBA), and microbial counts were investigated. SA coating enriched with the essential oil could reduce the spoilage of the fillets and extend their shelf-life. Samples treated with SA-containing HEO showed significantly (P < 0.05) lower TVB-N content and lipid oxidation, as reflected by lower PV, FFA and TBA values during the storage period compared with the SA and control. The treatment also reduced the degree of microbial deterioration of the fillets (about 1.5 log10 CFU/g) more efficiently than the SA.

  11. 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)

  12. Reduction of the inflammatory responses against alginate-poly-L-lysine microcapsules by anti-biofouling surfaces of PEG-b-PLL diblock copolymers.

    Directory of Open Access Journals (Sweden)

    Milica Spasojevic

    Full Text Available Large-scale application of alginate-poly-L-lysine (alginate-PLL capsules used for microencapsulation of living cells is hampered by varying degrees of success, caused by tissue responses against the capsules in the host. A major cause is proinflammatory PLL which is applied at the surface to provide semipermeable properties and immunoprotection. In this study, we investigated whether application of poly(ethylene glycol-block-poly(L-lysine hydrochloride diblock copolymers (PEG-b-PLL can reduce the responses against PLL on alginate-matrices. The application of PEG-b-PLL was studied in two manners: (i as a substitute for PLL or (ii as an anti-biofouling layer on top of a proinflammatory, but immunoprotective, semipermeable alginate-PLL100 membrane. Transmission FTIR was applied to monitor the binding of PEG-b-PLL. When applied as a substitute for PLL, strong host responses in mice were observed. These responses were caused by insufficient binding of the PLL block of the diblock copolymers confirmed by FTIR. When PEG-b-PLL was applied as an anti-biofouling layer on top of PLL100 the responses in mice were severely reduced. Building an effective anti-biofouling layer required 50 hours as confirmed by FTIR, immunocytochemistry and XPS. Our study provides new insight in the binding requirements of polyamino acids necessary to provide an immunoprotective membrane. Furthermore, we present a relatively simple method to mask proinflammatory components on the surface of microcapsules to reduce host responses. Finally, but most importantly, our study illustrates the importance of combining physicochemical and biological methods to understand the complex interactions at the capsules' surface that determine the success or failure of microcapsules applicable for cell-encapsulation.

  13. Characterization of smart auto-degradative hydrogel matrix containing alginate lyase to enhance levofloxacin delivery against bacterial biofilms.

    Science.gov (United States)

    Islan, German A; Dini, Cecilia; Bartel, Laura C; Bolzán, Alejandro D; Castro, Guillermo R

    2015-12-30

    The aim of the present work is the characterization of smart auto-degradable microspheres composed of calcium alginate/high methoxylated pectin containing an alginate lyase (AL) from Sphingobacterium multivorum and levofloxacin. Microspheres were prepared by ionotropic gelation containing AL in its inactive form at pH 4.0. Incubation of microspheres in Tris-HCl and PBS buffers at pH 7.40 allowed to establish the effect of ion-chelating phosphate on matrix erodability and suggested an intrinsically activation of AL by turning the pH close to neutrality. Scanning electron and optical microscopies revealed the presence of holes and surface changes in AL containing microspheres. Furthermore, texturometric parameters, DSC profiles and swelling properties were showing strong changes in microspheres properties. Encapsulation of levofloxacin into microspheres containing AL showed 70% efficiency and 35% enhancement of antimicrobial activity against Pseudomonas aeruginosa biofilm. Levofloxacin release from microspheres was not changed at acidic pH, but was modified at neutral pH in presence of AL. Advantageously, only gel matrix debris were detectable after overnight incubation, indicating an autodegradative gel process activated by the pH. Absence of matrix cytotoxicity and a reduction of the levofloxacin toxicity after encapsulation were observed in mammalian CHO-K1 cell cultures. These properties make the system a potent and versatile tool for antibiotic oral delivery targeted to intestine, enhancing the drug bioavailability to eradicate bacterial biofilm and avoiding possible intestinal obstructions.

  14. Encapsulation Red Ginger Oleoresin (Zingiber officinale var. Rubrum With Chitosan-alginate as Wall Material Using Spray Drying

    Directory of Open Access Journals (Sweden)

    Jayanudin

    2015-08-01

    Full Text Available Encapsulation is the process of protecting the active ingredients that is susceptible to environmental influences by using a coating. Red ginger oleoresin contains bioactive components that can be used as natural antioxidants, but sensitive to environmental influences. Chitosan-alginate nanoparticle is used as the coating, because it is safe for consumption and also stable. The purpose of this research was to determine the effect of the Tripolyphosphate (TPP concentration against the emulsion droplet size and determine the encapsulation efficiency of red ginger oleoresin. Encapsulation method was done by mixing 2% chitosan solution with 1% acetic acid, 1% sodium alginate and 8 g of red ginger oleoresin. The mixture was stirred and added sodium tripolyphosphate (3.5, 4.5 and 5.5%, respectively, emulsion preparation process was done by adding tween 80 (3, 4 and 5%, respectively and then stirred using homogenizer with a speed of 22,000 rpm, emulsions formed were analyzed using nano-particle analyzer. Emulsion formed was flowed on to the spray dryer inlet temperature of 180°C to form a powder encapsulation. Powder products were analyzed for determining encapsulation efficiency and morphology of red ginger oleoresin powder using Scanning Electron Microscopy (SEM. Based on the research results, the smallest droplet size of the emulsion was obtained at 481.5 nm and the largest encapsulation efficiency was as high as 70.59%.

  15. Proteomic analysis of the increased stress tolerance of saccharomyces cerevisiae encapsulated in liquid core alginate-chitosan capsules.

    Directory of Open Access Journals (Sweden)

    Johan O Westman

    Full Text Available Saccharomyces cerevisiae CBS8066 encapsulated in semi-permeable alginate or alginate-chitosan liquid core capsules have been shown to have an enhanced tolerance towards complex dilute-acid lignocellulose hydrolysates and the lignocellulose-derived inhibitor furfural, as well as towards high temperatures. The underlying molecular reasons for these effects have however not been elucidated. In this study we have investigated the response of the encapsulation on the proteome level in the yeast cells, in comparison with cells grown freely in suspension under otherwise similar conditions. The proteomic analysis was performed on whole cell protein extracts using nLC-MS/MS with TMT® labelling and 2-D DIGE. 842 and 52 proteins were identified using each method, respectively. The abundances of 213 proteins were significantly different between encapsulated and suspended cells, with good correlation between the fold change ratios obtained by the two methods for proteins identified in both. Encapsulation of the yeast caused an up-regulation of glucose-repressed proteins and of both general and starvation-specific stress responses, such as the trehalose biosynthesis pathway, and down-regulation of proteins linked to growth and protein synthesis. The encapsulation leads to a lack of nutrients for cells close to the core of the capsule due to mass transfer limitations. The triggering of the stress response may be beneficial for the cells in certain conditions, for example leading to the increased tolerance towards high temperatures and certain inhibitors.

  16. Alginate-polyester comacromer based hydrogels as physiochemically and biologically favorable entities for cardiac tissue engineering.

    Science.gov (United States)

    Thankam, Finosh G; Muthu, Jayabalan

    2015-11-01

    The physiochemical and biological responses of tissue engineering hydrogels are crucial in determining their desired performance. A hybrid comacromer was synthesized by copolymerizing alginate and poly(mannitol fumarate-co-sebacate) (pFMSA). Three bimodal hydrogels pFMSA-AA, pFMSA-MA and pFMSA-NMBA were synthesized by crosslinking with Ca(2+) and vinyl monomers acrylic acid (AA), methacrylic acid (MA) and N,N'-methylene bisacrylamide (NMBA), respectively. Though all the hydrogels were cytocompatible and exhibited a normal cell cycle profile, pFMSA-AA exhibited superior physiochemical properties viz non-freezable water content (58.34%) and water absorption per unit mass (0.97 g water/g gel) and pore length (19.92±3.91 μm) in comparing with other two hydrogels. The increased non-freezable water content and water absorption of pFMSA-AA hydrogels greatly influenced its biological performance, which was evident from long-term viability assay and cell cycle proliferation. The physiochemical and biological favorability of pFMSA-AA hydrogels signifies its suitability for cardiac tissue engineering.

  17. 大茴香醛改性海藻酸钠凝胶的制备及释药性能%Preparation of alginate gel modified by anise aldehyde and controlled release

    Institute of Scientific and Technical Information of China (English)

    吴敏; 倪才华

    2012-01-01

    Hydrophobically modified alginate were obtained through acetalization of alginate with p-methoxy benzaldehyde catalysted by an acid. The modified alginate was characterized by FTIR spectra, fluorescence, transmission electronic microscopy, scanning e-lectronic microscopy, UV spectrum, thermal analysis. The modified alginate hydrogel was used as a drug carrier for encapsulation and release of bovine serum albumin. The results showed that drug loading ability and slow release were observed.%在酸催化下使海藻酸钠与对甲氧基苯甲醛(又名大茴香醛)发生缩醛化反应,使其疏水改性,并将其制备成凝胶.利用红外(FFIR)、荧光、透射电镜(TEM)、扫描电镜(SEM)、紫外、热重分析(TGA)对产物进行了表征.结果表明,大茴香醛成功地与海藻酸钠发生了反应.该凝胶可以作为药物载体对牛血清白蛋白进行包埋释放,结果发现,改性后的产物其载药率和缓释性能比未改性的海藻酸钠有了一定的提高.

  18. 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

  19. 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).

  20. 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.

  1. 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

  2. Preventative Effects of Sodium Alginate on Indomethacin-induced Small-intestinal Injury in Mice.

    Science.gov (United States)

    Horibe, Sayo; Tanahashi, Toshihito; Kawauchi, Shoji; Mizuno, Shigeto; Rikitake, Yoshiyuki

    2016-01-01

    Recent advances in diagnostic technologies have revealed that nonsteroidal anti-inflammatory drugs (NSAIDs) can cause serious mucosal injury in the upper and lower gastrointestinal tract (including the small intestine). A drug to treat NSAID-induced small-intestinal injury (SII) is lacking. Sodium alginate is a soluble dietary fiber extracted from brown seaweed and its solution has been used as a hemostatic agent to treat gastrointestinal bleeding due to gastric ulcers. Whether sodium alginate has therapeutic effects on NSAID-induced SII and its mechanism of action are not known. Here, we investigated if administration of two forms (high-molecular-weight (HMW) and low-molecular-weight (LMW)) of sodium alginate could ameliorate indomethacin-induced SII. Pretreatment with HMW sodium alginate or LMW sodium alginate before indomethacin administration improved ulceration and the resultant intestinal shortening was associated with reduced histological severity of mucosal injury and ameliorated mRNA expression of inflammation-related molecules in the small intestine. We found that mRNAs of secretory Muc2 and membrane-associated Muc1, Muc3 and Muc4 were expressed in the small intestine. mRNA expression of Muc1-4 was increased in indomethacin-induced SII, and these increases were prevented by sodium alginate. Thus, administration of sodium alginate could be a therapeutic approach to prevent indomethacin-induced SII.

  3. Contamination level of alginate impressions arriving at a dental laboratory.

    Science.gov (United States)

    Sofou, A; Larsen, T; Fiehn, N-E; Owall, B

    2002-09-01

    The contamination level of alginate impressions delivered to a large dental laboratory in Sweden was determined. One hundred and seven consecutive alginate impressions were included during 7 days. Samples were taken and transferred into sterile physiological saline and analysed microbiologically for colony-forming units (cfu) as well as nonhemolytic, alpha-hemolytic, and beta-hemolytic colonies. After sampling, the clinics were contacted and asked to fill in simple questionnaires about their routines of disinfecting impressions. The questionnaire study revealed that about half of the clinics had some kind of disinfection routine, while the others rinsed in running water only. Seventy-two percent of the impressions yielded growth of bacteria, with a median number of 1.3x10(2) cfu. Thirteen per cent of the samples yielded >10(3) cfu, with a maximum number of 3.4x10(4) cfu. The majority of isolates were non- and alpha-hemolytic bacteria. Growth was recorded in 61.3% of disinfected impressions, and the numbers of bacteria in disinfected and nondisinfected impressions were similar. These findings raise the question of whether impressions need to be disinfected or if proper handling and hygienic procedures are sufficient to block the possible route of infection.

  4. 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.

  5. Physicochemical Characterization of Alginate Beads Containing Sugars and Biopolymers

    Directory of Open Access Journals (Sweden)

    Tatiana Aguirre Calvo

    2016-01-01

    Full Text Available Alginate hydrogels are suitable for the encapsulation of a great variety of biomolecules. Several alternatives to the conventional alginate formulation are being studied for a broad range of biotechnological applications; among them the addition of sugars and biopolymers arises as a good and economic strategy. Sugars (trehalose and β-cyclodextrin, a cationic biopolymer (chitosan, an anionic biopolymer (pectin, and neutral gums (Arabic, guar, espina corona, and vinal gums provided different characteristics to the beads. Here we discuss the influence of beads composition on several physicochemical properties, such as size and shape, analyzed through digital image analysis besides both water content and activity. The results showed that the addition of a second biopolymer, β-CD, or trehalose provoked more compact beads, but the fact that they were compact not necessarily implies a concomitant increase in their circularity. Espina corona beads showed the highest circularity value, being useful for applications which require a controlled and high circularity, assuring quality control. Beads with trehalose showed lower water content than the rest of the system, followed by those containing galactomannans (espina corona, vinal, and guar gums, revealing polymer structure effects. A complete characterization of the beads was performed by FT-IR, assigning the characteristics bands to each individual component.

  6. Preparation of alginate-gelatin capsules and its properties

    Institute of Scientific and Technical Information of China (English)

    Xiao-yan LI; Xi-guang CHEN; Cheng-sheng LIU; Chen-guang LIU; Yu-ping XUE

    2008-01-01

    Capsules based on alginate and gelatin prepared by extrusion method could increase the cell numbers of Lactobacillus casei ATCC 393 to be 108 CFU·9-1 in the wet state of the capsules. The capsules were spherical, smooth-surfaced and non-aggregated with a diameter of (4.0±0.3) mm. The behavior of the samples were quite similar at low relative humidity (33%, 52%) and the ratio of weight change reached 93%. Four kinds of capsules in simulated gastric fluid (SGF) exhibited shrinkage while the beads eroded accompanied with slight swelling in simulated intestinal fluid (SIF). The pH values affected the stability of the capsules and with the increase in pH, the capsules chan-ged from shrank then swelled and finally, broke into pieces. The capsules behaved differently under different ion intens-ities and the introduction of gelatin weakened the stability of capsules compared with the alginate ones. Cells of L. casei ATCC 393 could be continuously released from the capsules in the simulated gastrointestinal tract (GIT) and the release amounts and speeds in SIF were much higher and faster than those in SGF.

  7. POLYPEPTIDE EXTRACTION FROM ALGINATE HYDROGELS in vitro AND in vivo

    Directory of Open Access Journals (Sweden)

    T. V. Shkand

    2014-06-01

    Full Text Available Dependence of rheological and diffusion properties of gels on their composition as well as desorption of active components from the resulted implants in biological objects have been studied. The work has been performed in vitro using step-wise extraction of polypeptides form the heart of newborn piglets and also in vivo by implanting the «gel-extract» complex into muscular tissue of rats. The dynamics of peptide transfer was assessed using photometric and fluorometric methods. It has been established that with the growth of alginate concentration in gel there is a transition from convective mechanism of mass transfer to molecular diffusion. The study of the dynamics of mass transfer of fluorescent protein (R-phycoerythrin has shown that peptides release from a gel into surrounding tissues for 5 hrs with the rate of 8‒9% per hours with following decrease in the extraction rate due to cross diffusion, which contributes to prolonged effect of peptides to a target organ. Thus the data presented about mass transfer in alginate gels should be taken into account when designing the compositions of «peptide-extract gels» during transplantation into biological objects.

  8. Contamination level of alginate impressions arriving at a dental laboratory.

    Science.gov (United States)

    Sofou, A; Larsen, T; Fiehn, N-E; Owall, B

    2002-09-01

    The contamination level of alginate impressions delivered to a large dental laboratory in Sweden was determined. One hundred and seven consecutive alginate impressions were included during 7 days. Samples were taken and transferred into sterile physiological saline and analysed microbiologically for colony-forming units (cfu) as well as nonhemolytic, alpha-hemolytic, and beta-hemolytic colonies. After sampling, the clinics were contacted and asked to fill in simple questionnaires about their routines of disinfecting impressions. The questionnaire study revealed that about half of the clinics had some kind of disinfection routine, while the others rinsed in running water only. Seventy-two percent of the impressions yielded growth of bacteria, with a median number of 1.3x10(2) cfu. Thirteen per cent of the samples yielded >10(3) cfu, with a maximum number of 3.4x10(4) cfu. The majority of isolates were non- and alpha-hemolytic bacteria. Growth was recorded in 61.3% of disinfected impressions, and the numbers of bacteria in disinfected and nondisinfected impressions were similar. These findings raise the question of whether impressions need to be disinfected or if proper handling and hygienic procedures are sufficient to block the possible route of infection. PMID:12271349

  9. 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.

  10. Bioactive inorganic-materials/alginate composite microspheres with controllable drug-delivery ability.

    Science.gov (United States)

    Wu, Chengtie; Zhu, Yufang; Chang, Jiang; Zhang, Yufeng; Xiao, Yin

    2010-07-01

    Alginate microspheres are considered a promising material as a drug carrier in bone repair because of excellent biocompatibility, but their main disadvantage is low drug entrapment efficiency and noncontrollable release. The aim of this study was to investigate the effect of incorporating mesoporous bioglass (MBG), nonmesoporous bioglass (BG), or hydroxyapatite (HAp) into alginate microspheres on their drug-loading and release properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and atomic emission spectroscopy (AES) were used to analyze the composition, structure, and dissolution of bioactive inorganic materials and their microspheres. Dexamethasone (DEX)-loading and release ability of four microspheres were tested in phosphate buffered saline with varying pH. Results showed that the drug-loading capacity was enhanced with the incorporation of bioactive inorganic materials into alginate microspheres. The MBG/alginate microspheres had the highest drug loading ability. DEX release from alginate microspheres correlated to the dissolution of MBG, BG, and HAp in PBS, and that the pH was an efficient factor in controlling the DEX release; a high pH resulted in greater DEX release, whereas a low pH delayed DEX release. In addition, MBG/alginate, BG/alginate, and HAp/alginate microspheres had varying apatite-formation and dissolution abilities, which indicate that the composites would behave differently with respect to bioactivity. The study suggests that microspheres made of a composite of bioactive inorganic materials and alginate have a bioactivity and degradation profile which greatly improves their drug delivery capacity, thus enhancing their potential applications as bioactive filler materials for bone tissue regeneration. PMID:20225253

  11. 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

  12. Three-dimensional bioprinting of complex cell laden alginate hydrogel structures.

    Science.gov (United States)

    Tabriz, Atabak Ghanizadeh; Hermida, Miguel A; Leslie, Nicholas R; Shu, Wenmiao

    2015-12-21

    Different bioprinting techniques have been used to produce cell-laden alginate hydrogel structures, however these approaches have been limited to 2D or simple three-dimension (3D) structures. In this study, a new extrusion based bioprinting technique was developed to produce more complex alginate hydrogel structures. This was achieved by dividing the alginate hydrogel cross-linking process into three stages: primary calcium ion cross-linking for printability of the gel, secondary calcium cross-linking for rigidity of the alginate hydrogel immediately after printing and tertiary barium ion cross-linking for long-term stability of the alginate hydrogel in culture medium. Simple 3D structures including tubes were first printed to ensure the feasibility of the bioprinting technique and then complex 3D structures such as branched vascular structures were successfully printed. The static stiffness of the alginate hydrogel after printing was 20.18 ± 1.62 KPa which was rigid enough to sustain the integrity of the complex 3D alginate hydrogel structure during the printing. The addition of 60 mM barium chloride was found to significantly extend the stability of the cross-linked alginate hydrogel from 3 d to beyond 11 d without compromising the cellular viability. The results based on cell bioprinting suggested that viability of U87-MG cells was 93 ± 0.9% immediately after bioprinting and cell viability maintained above 88% ± 4.3% in the alginate hydrogel over the period of 11 d.

  13. 医用藻酸盐敷料体外降解的研究%The Study of the Degradation for Medical Alginate Dressings in Vitro

    Institute of Scientific and Technical Information of China (English)

    陈锦涛; 李婷; 熊亮; 唐汉颖

    2016-01-01

    研究藻酸盐医用敷料体外降解的规律及不同降解时间其产物对内皮细胞增殖情况的影响,为藻酸盐医用敷料在临床使用中提供参考。以PBS缓冲液(模拟体液环境)为降解介质,对藻酸盐敷料进行体外降解;用藻酸盐敷料的失重率、分子质量变化表征本体的变化规律;用降解液中降解产物的糖醛酸含量变化表征降解产物的变化规律。将降解液与内皮细胞共培养,用MTT法检测内皮细胞增殖情况。藻酸盐敷料在模拟体液环境条件下,可以被降解,42 d失重率为61畅2%,降解过程中其分子质量逐渐减小,最终产物为糖醛酸,其浓度不断增大。不同时间的降解产物均能促进内皮细胞的增殖。藻酸盐医用敷料体外降解比较快,完全降解的最终产物为糖醛酸,其降解液可以促进内皮细胞的增殖、分化,提高细胞新陈代谢能力,增加新细胞的再生速度,促进伤口的愈合。%To study the degradation of medical alginate dressings in PBS buffer and the effect of degradation products on proliferation of endothelial cells as well as to provide the reference for medical alginate dressings in clinical use , the degradation was prepared by immersing the medical alginate dressings in PBS buffer ( SBF environ-ment) under aseptic condition .The weight loss rate and molecular weigh were measured .On the other hand,the ur-onate concentration of degradation products were measured .The human umbilical vein endothelial cells ECV-304 was used and cultured with the degradation fluid .Cell proliferation was detected with MTT assay .Medical alginate dressings in a simulated body fluid environmental conditions can be degraded .The weight loss was 61.2%in 42 d. The molecular weight decreased with the increasing of degradation time .The final product of medical alginate dress-ings was uronic acid and the concentration of uronic acid increased with the increasing of

  14. A new heterogeneous acid catalyst for esterification: Optimization using response surface methodology

    International Nuclear Information System (INIS)

    Highlight: ► Esterification of lauric acid with ferric-alginate gives 99% conversion. ► Optimized conditions are 0.16:1 ferric-alginate to lauric acid mass ratio and 16:1 methanol to lauric acid molar ratio. ► The conditions were optimized using Central Composite Design (CCD). ► Esterification of PFAD using the optimized conditions gave 89% yield. - Abstract: Studies on heterogeneous acid catalysts for converting free fatty acids into biodiesel have been intensified over the years. This paper focuses on the optimization of a new catalyst system, ferric-alginate as a heterogeneous acid catalyst to esterify lauric acid into methyl laurate. Methanol to lauric acid molar ratio and catalyst amount was optimized using response surface methodology (RSM). The best reaction conditions to achieve methyl laurate yield of 99% was found to be 0.16:1 ferric-alginate to lauric acid mass ratio and 16:1 methanol to lauric acid molar ratio. The reaction time and temperature was fixed at 3 h and methanol refluxing temperature, respectively. The optimized reaction conditions were also used to esterify palm fatty acid distillate to give 89% methyl esters conversion. The acid value of palm fatty acid distillate (PFAD) was reduced from 228 to 0.8 mg KOH/g PFAD.

  15. 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.

  16. 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

  17. Electrochemical Hydrogel Lithography of Calcium-Alginate Hydrogels for Cell Culture

    Directory of Open Access Journals (Sweden)

    Fumisato Ozawa

    2016-08-01

    Full Text Available Here we propose a novel electrochemical lithography methodology for fabricating calcium-alginate hydrogels having controlled shapes. We separated the chambers for Ca2+ production and gel formation with alginate with a semipermeable membrane. Ca2+ formed in the production chamber permeated through the membrane to fabricate a gel structure on the membrane in the gel formation chamber. When the calcium-alginate hydrogels were modified with collagen, HepG2 cells proliferated on the hydrogels. These results show that electrochemical hydrogel lithography is useful for cell culture.

  18. 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

  19. 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

  20. 氧化海藻酸钠应用于体外循环管路**%Oxidized sodium alginate used in an extracorporeal circulation pipe

    Institute of Scientific and Technical Information of China (English)

    李金友; 李彤; 于美丽; 高文卿; 胡晓旻; 陆海滨; 于广栋

    2013-01-01

      背景:目前体外循环肝素涂层管路应用较广,但是价格昂贵,限制了其广泛应用。  目的:将多醛基海藻酸钠涂层到医用聚氯乙烯体外循环管路,筛选出最佳涂层条件和所制备管路的稳定性及抗凝性能。  方法:利用高碘酸钠氧化海藻酸钠,制备高碘酸钠和海藻酸钠摩尔比分别为1∶8、1∶10和1∶12的多醛基氧化海藻酸钠,采用化学结合的方法将不同氧化度海藻酸钠固定到医用聚氯乙烯体外循环管路表面,筛选出最佳氧化度。以硫酸浓度、聚乙烯亚胺浓度、氧化海藻酸钠浓度、氧化海藻酸钠pH值和温度为因素,采用正交实验筛选最佳涂层条件,评价所制备管路氧化海藻酸钠固定的稳定性及抗凝血性能,并与空白对照组和肝素涂层组进行比较和分析。  结果与结论:氧化海藻酸钠最佳氧化度为高碘酸钠和海藻酸钠摩尔比为1∶10。筛选出的最佳涂层条件为50%浓硫酸、0.05%聚乙烯亚胺、反应溶液pH值为3.5、反应温度为40℃和氧化海藻酸钠质量浓度为2 g/L。氧化海藻酸钠涂层管路组脱落率与肝素涂层组有相似的结果,抗凝血性能稍劣于肝素涂层组(P OBJECTIVE:To screen the optimal coating condition of oxidated sodium alginate as a coating material to coat the medical polyvinyl chloride pipe and to evaluate the anticoagulant properties and the stability of the coated pipe. METHODS:Oxidized sodium alginate was prepared with sodium periodate, and the mole ratio of sodium periodate and sodium alginate was 1:8, 1:10 and 1:12, respectively. Oxidized sodium alginate with different degree of oxidation was coated on the surface of medical polyvinyl chloride pipes by chemical methods, then to select the best degree of oxidation. The optimal coating condition was screened through an orthogonal experiment based on concentrations of sulfuric acid, polyethyleneimine and oxidized

  1. Effect of microencapsulation of Lactobacillus plantarum 25 into alginate/chitosan/alginate microcapsules on viability and cytokine induction.

    Science.gov (United States)

    Jiang, Tao; Kim, You-Kyoung; Singh, Bijay; Kang, Sang-Kee; Choi, Yun-Jaie; Cho, Chong-Su

    2013-08-01

    Lactobacillus plantarum 25 (LP25) encapsulated into alginate/chitosan/alginate (ACA) microcapsules (LP25-ACA MCs) prepared by an extrusion methods were characterized to assess their efficacy in oral delivery. The particle sizes of LP25-ACA MCs were 1.11 +/- 0.32 mm. The loading content of LP25 was 1.11 x 10(7) colony forming unit (cfu)/microcapsule and encapsulation efficiency was above 98%. The viability of LP25 in ACA MCs was more than 65% in simulated gastric fluid (SGF, pH 2.0) and 75% in simulated small intestinal fluid (SIF, pH 7.2) up to 2 h. Encapsulated LP25 were completely released from LP25-ACA MCs in SIF and simulated colon fluid (SCF, pH 6.0) within 12 h and 8 h respectively. The viability of LP25 in ACA MCs till 5 weeks was above 58%, whereas viability of free LP25 stored at room temperature up to 5 weeks was zero. Besides, LP25-ACA MCs induced the secretion of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) from macrophages and dendritic cells showing the immunomodulatory effect of LP25. These findings demonstrate that the encapsulation of LP25 by ACA is a suitable strategy for oral delivery of probiotics.

  2. Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Highlights: • Calcium-alginate-modified dien-silica gel adsorbed multivalent metal ions. • Metal ions adsorbed on CaAD were eluted using low acidic concentrations. • Flow system with CaAD-packed column enriched metal concentrations up to 50-fold. - Abstract: This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1 mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3–4 solutions containing 1.0 × 10−6 M of heavy metal ions at a flow rate of 5.0 mL min−1. Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05–0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu2+, Zn2+, and Pb2+ by 50-fold. This new enrichment system successfully performed the separation and determination of Cu2+ (5.0 × 10−8 M) and Zn2+ (5.7 × 10−8 M) in a river water sample and Pb2+ (3.8 × 10−9 M) in a ground water sample

  3. 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

  4. 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.

  5. 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

    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...... 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.......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...

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

    Science.gov (United States)

    Maruyama, Yukie; Itoh, Takafumi; Nishitani, Yu; Mikami, Bunzo; Hashimoto, Wataru; Murata, Kousaku

    2012-03-01

    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 P2(1)2(1)2(1), with unit-cell parameters a = 72.5, b = 136.8, c = 273.3 Å, suggesting the presence of one complex in the asymmetric unit.

  7. 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

  8. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira de Lima, Daniel; Gomes Aimoli, Cassiano [Faculdade de Engenharia Quimica, Unicamp, CP6066 CEP13083-970, Campinas, SP (Brazil); Beppu, Marisa Masumi, E-mail: beppu@feq.unicamp.br [Faculdade de Engenharia Quimica, Unicamp, CP6066 CEP13083-970, Campinas, SP (Brazil)

    2009-05-05

    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.

  10. 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.

  11. Effects of Alginate Gel on Rheological Properties of Hair-tail( Trichiurus lepturus) Surimi

    Institute of Scientific and Technical Information of China (English)

    XUE Yong; LIU Xin; ZHANG Lili; LIN Dan; XU Jiachao; XUE Changhu

    2011-01-01

    Effects of alginate gel at different concentrations on rheological properties of hair-tail (Trichiurus lepturus) surimi were investigated. Alginate gel (1%-3%) exhibited enhanced effects, especially when alginate gel concentration increased. The rheologicai properties of mixture samples were studied by the time sweep, frequency sweep and temperature sweep. The critical strain values of the mixture samples for the onset of non-linear viscoelasticity were about 5%. The storage modulus G' of the mixture samples increased with time for 4 h. The frequency sweep showed that G' was greater than G" for all the mixture gels with different alginate gel concentrations, and values of both n' and n" for all samples were low (<0.2), these constants corresponding to G' and G", and indicating the elasticity of mixture gels. The values of storage modulus G' decreased during heating process and increased with decreasing temperature.

  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. 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

  14. Reduction of graphene oxide/alginate composite hydrogels for enhanced adsorption of hydrophobic compounds.

    Science.gov (United States)

    Kim, Semin; Yoo, Youngjae; Kim, Hanbit; Lee, Eunju; Lee, Jae Young

    2015-10-01

    Carbon-based materials, consisting of graphene oxide (GO) or reduced GO (rGO), possess unique abilities to interact with various molecules. In particular, rGO materials hold great promise for adsorption and delivery applications of hydrophobic molecules. However, conventional production and/or usage of rGO in aqueous solution often causes severe aggregation due to its low water solubility and thus difficulties in handling and applications. In our study, to prevent the severe aggregation of GO during reduction and to achieve a high adsorption capacity with hydrophobic compounds, GO/alginate composite hydrogels were first prepared and then reduced in an aqueous ascorbic acid solution at 37 °C. Adsorption studies with a model hydrophobic substance, rhodamine B, revealed that the reduced composite hydrogels are more highly absorbent than the unreduced hydrogels. In addition, the adsorption properties of the composite hydrogels, which are consequences of hydrophobic and ionic interactions, could be modulated by controlling the degree of reduction for the adsorption of different molecules. The composite hydrogels embedding rGO can be very useful in applications related to drug delivery, waste treatment, and biosensing.

  15. Biodegradable IPN hydrogel beads of pectin and grafted alginate for controlled delivery of diclofenac sodium.

    Science.gov (United States)

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

    2013-05-01

    A novel diclofenac sodium (DS) loaded interpenetrating polymer network (IPN) beads of pectin and hydrolyzed polyacrylamide-graft-sodium alginate (PAAm-g-SA) was developed through ionotropic gelation and covalent cross-linking. The graft copolymer was synthesized by free radical polymerization under the nitrogen atmosphere followed by alkaline hydrolysis. The grafting, alkaline hydrolysis, and characterization of beads were confirmed by Fourier transforms infrared spectroscopy. The crystalline structure of drug after encapsulation into IPN beads were evaluated by differential scanning colorimetry and X-ray diffraction analyses. DS encapsulation was up to 96.45 %. The effect of hydrolyzed graft copolymer/pectin ratios and glutaraldehyde concentration on drug release in acidic and phosphate buffer solutions were investigated. The release of drug was significantly increased with increase of pH. The release of drug depends on the extent of cross-linking. The results indicated that IPN beads of hydrolyzed PAAm-g-SA and pectin could be used for sustained release of DS.

  16. Natural polyelectrolyte self-assembled multilayers based on collagen and alginate: stability and cytocompatibility.

    Science.gov (United States)

    Li, Wenxing; Zhao, Peng; Lin, Chao; Wen, Xuejun; Katsanevakis, Eleni; Gero, Decher; Félix, Olivier; Liu, Yuehua

    2013-08-12

    Scientific interest in the self-assembly of collagen composite films has been increasing for their potential application in constructing bioactive materials. Here we report a highly stable and cytocompatible collagen/alginate (COL/ALG) ultrathin film, which was linearly fabricated via a layer-by-layer self-assembled technique. The variation in morphology and thickness of the films in air and in solutions with different pH and ion values were tested by atomic force microscopy. Results showed that the solutions with high pH values or solutions that contained electrolytes would disintegrate the film, while films with that were cross-linked for a long time prevented the dissolution and contributed to stability maintenance of the films. Interestingly, the COL/ALG coating not only improved the adhesion and proliferation of the human periodontal ligament cells, but also modified the morphology and migration of cells on the surface of glass and poly-L-lactic acid (PLA) electrospun scaffolds. In conclusion, the COL/ALG ultrathin films were highly stable and cytocompatible and could be easily fabricated by the cost-effective self-assembled technique presented. The findings of this study have the potential to play an important role in the surface modification of biomaterials. PMID:23782041

  17. Preparation and characterization of Ganoderma lucidum spores-loaded alginate microspheres by electrospraying.

    Science.gov (United States)

    Zhao, Ding; Li, Jing-Song; Suen, William; Chang, Ming-Wei; Huang, Jie

    2016-05-01

    Ganoderma lucidum spores (GLSs), popular functional food in preventive medicine, are susceptible to oxidative and acidic degradation during processing, storage and oral administration, resulting in the loss of sensory and nutritional qualities. The main objective of the study was to encapsulate the GLS in order to fully preserve the bioactivity of the ingredients as well as providing controlled and targeted delivery. Electrospraying was applied to prepare GLS-Alginate (GLS/A) micro beads in the current study. The size of GLS/A beads can be tailored by varying the applied voltage and drying processes. pH responsive release profiles of GLS/A beads were revealed from in vitro study in a simulated gastrointestinal environment: no release of GLS encapsulated beads in the simulated gastric fluid (pH of 1.8) was observed; while a rapid, size dependent release was found in the simulated intestinal solution (pH of 7.5). The release from smaller beads (e.g. 600 μm) was 1.5 times faster than that of larger beads (e.g. 2000 μm). In addition, the GLS release from freeze dried beads was almost 3 times faster than those of air and vacuum dried beads in the first 90 min. The present results illustrate the potential to protect GLS by encapsulation using electrospraying to achieve the controlled release of GLS ingredients. This will pave the way to develop effective GLS products with desirable bioactive components for healthcare applications.

  18. Promotive effects of alginate-derived oligosaccharides on the inducing drought resistance of tomato

    Science.gov (United States)

    Liu, Ruizhi; Jiang, Xiaolu; Guan, Huashi; Li, Xiaoxia; Du, Yishuai; Wang, Peng; Mou, Haijin

    2009-09-01

    In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato ( Lycopersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6 molL-1 PEG-6000 solution for 6 h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

  19. Promotive Effects of Alginate-Derived Oligosaccharides on the Inducing Drought Resistance of Tomato

    Institute of Scientific and Technical Information of China (English)

    LIU Ruizhi; JIANG Xiaolu; GUAN Huashi; LI Xiaoxia; DU Yishuai; WANG Peng; MOU Haijin

    2009-01-01

    In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Lycopersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6molL-I PEG-6000 solution for 6h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

  20. Preparation and characterization of Ganoderma lucidum spores-loaded alginate microspheres by electrospraying.

    Science.gov (United States)

    Zhao, Ding; Li, Jing-Song; Suen, William; Chang, Ming-Wei; Huang, Jie

    2016-05-01

    Ganoderma lucidum spores (GLSs), popular functional food in preventive medicine, are susceptible to oxidative and acidic degradation during processing, storage and oral administration, resulting in the loss of sensory and nutritional qualities. The main objective of the study was to encapsulate the GLS in order to fully preserve the bioactivity of the ingredients as well as providing controlled and targeted delivery. Electrospraying was applied to prepare GLS-Alginate (GLS/A) micro beads in the current study. The size of GLS/A beads can be tailored by varying the applied voltage and drying processes. pH responsive release profiles of GLS/A beads were revealed from in vitro study in a simulated gastrointestinal environment: no release of GLS encapsulated beads in the simulated gastric fluid (pH of 1.8) was observed; while a rapid, size dependent release was found in the simulated intestinal solution (pH of 7.5). The release from smaller beads (e.g. 600 μm) was 1.5 times faster than that of larger beads (e.g. 2000 μm). In addition, the GLS release from freeze dried beads was almost 3 times faster than those of air and vacuum dried beads in the first 90 min. The present results illustrate the potential to protect GLS by encapsulation using electrospraying to achieve the controlled release of GLS ingredients. This will pave the way to develop effective GLS products with desirable bioactive components for healthcare applications. PMID:26952490

  1. Reduction of graphene oxide/alginate composite hydrogels for enhanced adsorption of hydrophobic compounds

    Science.gov (United States)

    Kim, Semin; Yoo, Youngjae; Kim, Hanbit; Lee, Eunju; Lee, Jae Young

    2015-10-01

    Carbon-based materials, consisting of graphene oxide (GO) or reduced GO (rGO), possess unique abilities to interact with various molecules. In particular, rGO materials hold great promise for adsorption and delivery applications of hydrophobic molecules. However, conventional production and/or usage of rGO in aqueous solution often causes severe aggregation due to its low water solubility and thus difficulties in handling and applications. In our study, to prevent the severe aggregation of GO during reduction and to achieve a high adsorption capacity with hydrophobic compounds, GO/alginate composite hydrogels were first prepared and then reduced in an aqueous ascorbic acid solution at 37 °C. Adsorption studies with a model hydrophobic substance, rhodamine B, revealed that the reduced composite hydrogels are more highly absorbent than the unreduced hydrogels. In addition, the adsorption properties of the composite hydrogels, which are consequences of hydrophobic and ionic interactions, could be modulated by controlling the degree of reduction for the adsorption of different molecules. The composite hydrogels embedding rGO can be very useful in applications related to drug delivery, waste treatment, and biosensing.

  2. Biodegradable IPN hydrogel beads of pectin and grafted alginate for controlled delivery of diclofenac sodium.

    Science.gov (United States)

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

    2013-05-01

    A novel diclofenac sodium (DS) loaded interpenetrating polymer network (IPN) beads of pectin and hydrolyzed polyacrylamide-graft-sodium alginate (PAAm-g-SA) was developed through ionotropic gelation and covalent cross-linking. The graft copolymer was synthesized by free radical polymerization under the nitrogen atmosphere followed by alkaline hydrolysis. The grafting, alkaline hydrolysis, and characterization of beads were confirmed by Fourier transforms infrared spectroscopy. The crystalline structure of drug after encapsulation into IPN beads were evaluated by differential scanning colorimetry and X-ray diffraction analyses. DS encapsulation was up to 96.45 %. The effect of hydrolyzed graft copolymer/pectin ratios and glutaraldehyde concentration on drug release in acidic and phosphate buffer solutions were investigated. The release of drug was significantly increased with increase of pH. The release of drug depends on the extent of cross-linking. The results indicated that IPN beads of hydrolyzed PAAm-g-SA and pectin could be used for sustained release of DS. PMID:23423649

  3. Study of the immunoisolating effects of barium-alginate microencapsulation on rat islets allograft survival

    Institute of Scientific and Technical Information of China (English)

    Mei Zhang; Chao Liu; Cuiping Liu; Youwen Qin; Zhaosun Zhen

    2005-01-01

    Objective: To evaluate the immunoisolating effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets were transplanted under the kidney capsule or intraperitoneally into Wistar rat with STZ-induced diabetes. The blood glucose and insulin secretion of grafts were observed. Graft function was tested by oral rats was associated with normal glucose and insulin profiles in response to OGTT. Conclusion: Microencapsulation with barium-alginate membrane can prolong islet survival and protect islets against allorejection.

  4. 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...

  5. 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...

  6. Microfluidic Encapsulation of Pickering Oil Microdroplets into Alginate Microgels for Lipophilic Compound Delivery

    OpenAIRE

    Marquis, Melanie; Alix, Valentin; Capron, Isabelle; Cuenot, Stephane; Zykwinska, Agata

    2016-01-01

    Alginate microgels are widely used as delivery systems in food, cosmetics, and pharmaceutical industries for encapsulation and sustained release of hydrophilic compounds and cells. However, the encapsulation of lipophilic molecules inside these microgels remains a great challenge because of the complex oil-core matrix required. The present study describes an original two-step approach allowing the easy encapsulation of several oil microdroplets within alginate microgels. In the first step, st...

  7. 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 ...

  8. 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 ...

  9. Process engineering of high voltage alginate encapsulation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Gryshkov, Oleksandr, E-mail: gryshkov@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Pogozhykh, Denys, E-mail: pogozhykh@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Zernetsch, Holger, E-mail: zernetsch@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Hofmann, Nicola, E-mail: hofmann@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany); Mueller, Thomas, E-mail: mueller.thomas@mh-hannover.de [Institute for Transfusion Medicine, Medical School Hannover, D-30625 Hannover (Germany); Glasmacher, Birgit, E-mail: glasmacher@imp.uni-hannover.de [Institute for Multiphase Processes, Leibniz University Hannover, D-30167 Hannover (Germany)

    2014-03-01

    Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200–400 μm) with narrow size distribution (± 5–7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15–25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate–cell interaction within these structures will be forthcoming. - Highlights: • High voltage alginate encapsulation of mesenchymal stem cells (MSCs) was designed. • Reproducible and spherical alginate beads were generated via high voltage. • Air flow encapsulation was utilized as a comparative approach to high voltage. • High voltage did not alter the viability and proliferation of encapsulated MSCs. • High voltage encapsulation can be scaled up and applied in cell-based therapy.

  10. Alginate modification with the coupling of primary amines relevant for nerve regeneration

    OpenAIRE

    Abdoli Najmi, Maryam

    2014-01-01

    Alginate is a polysaccharide produced by brown seaweed and some bacteria which is highly demanded in biomedical researches. It can form a gel in presence of divalent cations which has many applications in cell based therapy. Alginate can be used as immobilization matrix for transplanted cells in vivo to protect the transplanted cells against host immune system. It can be modified by coupling with adhesive peptides such as RGD to improve adhesion property for cell entrapment, relevant for tiss...

  11. 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

  12. Preparation of alginate-chitosan fibers with potential biomedical applications.

    Science.gov (United States)

    Sibaja, Bernal; Culbertson, Edward; Marshall, Patrick; Boy, Ramiz; Broughton, Roy M; Solano, Alejandro Aguilar; Esquivel, Marianelly; Parker, Jennifer; De La Fuente, Leonardo; Auad, Maria L

    2015-12-10

    The preparation of alginate-chitosan fibers, through wet spinning technique, as well as the study of their properties as a function of chitosan's molecular weight and retention time in the coagulation bath, is presented and discussed in this work. Scanning electron microscopy (SEM) revealed that the fibers presented irregular and rough surfaces, with a grooved and heavily striated morphology distributed throughout the structure. Dynamic mechanical analysis (DMA) showed that, with the exception of elongation at break, the incorporation of chitosan into the fibers improved their tensile properties. The in vitro release profile of sulfathiazole as a function of chitosan's molecular weight indicated that the fibers are viable carriers of drugs. Kinetic models showed that the release of the model drug is first-order, and the release mechanism is governed by the Korsmeyer-Peppas model. Likewise, fibers loaded with sulfathiazole showed excellent inhibition of Escherichia coli growth after an incubation time of 24h at 37 °C. PMID:26428163

  13. 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.

  14. 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

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

    Science.gov (United States)

    Klinkajon, Wimonwan; Supaphol, Pitt

    2014-08-01

    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) (Cu(2+)) sulfate solution. In the second step, the films were further cross-linked in a corresponding Cu(2+) sulfate solution using a dipping method to further improve their dimensional stability. Alginate solution (at 2%w/v) and Cu(2+) sulfate solution (at 2%w/v) in acetate buffer at a low pH provided soft films with excellent swelling behavior. An increase in either Cu(2+) 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 Cu(2+) 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.

  16. 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

  17. 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.

  18. 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

  19. An additive manufacturing-based PCL-alginate-chondrocyte bioprinted scaffold for cartilage tissue engineering.

    Science.gov (United States)

    Kundu, Joydip; Shim, Jin-Hyung; Jang, Jinah; Kim, Sung-Won; Cho, Dong-Woo

    2015-11-01

    Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self-assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three-dimensional (3D) cell-printed scaffolds using layer-by-layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell-encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell-based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL-alginate gel constructs. PCL-alginate gels containing transforming growth factor-β (TGFβ) showed higher ECM formation. The 3D cell-printed scaffolds of PCL-alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL-alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell-printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. PMID:23349081

  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. Calcium alginate microcapsule generation on a microfluidic system fabricated using the optical disk process

    Science.gov (United States)

    Huang, Keng-Shiang; Liu, Ming-Kai; Wu, Chun-Han; Yen, Yu-Tang; Lin, Yu-Cheng

    2007-08-01

    This paper describes the generation of monodisperse calcium alginate (Ca-alginate) microcapsules on a microfluidic platform using the commercial optical disk process. Our strategy is based on combining the rapid injection molding process for a cross-junction microchannel with the sheath focusing effect to form uniform water-in-oil (w/o) emulsions. These emulsions, consisting of 1.5% (w/v) sodium alginate (Na-alginate), are then dripped into a solution containing 20% (w/v) calcium chloride (CaCl2) creating Ca-alginate microparticles in an efficient manner. This paper demonstrates that the size of Ca-alginate microparticles can be controlled from 20 µm to 50 µm in diameter with a variation of less than 10%, simply by altering the relative sheath/sample flow rate ratio. Experimental data show that for a given fixed dispersed phase flow (sample flow), the emulsion size decreases as the average flow rate of the continuous phase flow (sheath flow) increases. The proposed microfluidic platform is capable of generating relatively uniform emulsions and has the advantages of active control of the emulsion diameter, a simple and low cost process and a high throughput.

  2. 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

  3. 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)

  4. Evaluation of Gene Expression and Alginate Production in Response to Oxygen Transfer in Continuous Culture of Azotobacter vinelandii

    Science.gov (United States)

    Díaz-Barrera, Alvaro; Martínez, Fabiola; Guevara Pezoa, Felipe; Acevedo, Fernando

    2014-01-01

    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 tailor

  5. 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

  6. Mussel-inspired alginate gel promoting the osteogenic differentiation of mesenchymal stem cells and anti-infection.

    Science.gov (United States)

    Zhang, Shiwen; Xu, Kaige; Darabi, Mohammad Ali; Yuan, Quan; Xing, Malcolm

    2016-12-01

    Alginate hydrogels have been used in cell encapsulation for many years but a prevalent issue with pure alginates is that they are unable to provide enough bioactive properties to interact with mammalian cells. This paper discusses the modification of alginate with mussel-inspired dopamine for cell loading and anti-infection. Mouse bone marrow stem cells were immobilized into alginate and alginate-dopamine beads and fibers. Through live-dead and MTT assay, alginates modified by dopamine promoted cell viability and proliferation. In vitro cell differentiation results showed that such an alginate-dopamine gel can promote the osteogenic differentiation of mesenchymal stem cell after PCR and ALP assays. In addition to that, the adhesive prosperities of dopamine allowed for coating the surface of alginate-dopamine gel with silver nanoparticles, which provided the gel with significant antibacterial characteristics. Overall, these results demonstrate that a dopamine-modified alginate gel can be a great tool for cell encapsulation to promote cell proliferation and can be applied to bone regeneration, especially in contaminated bone defects. PMID:27612740

  7. Post-crosslinking towards stimuli-responsive sodium alginate beads for the removal of dye and heavy metals.

    Science.gov (United States)

    Lu, Ting; Xiang, Tao; Huang, Xue-Lian; Li, Cheng; Zhao, Wei-Feng; Zhang, Qian; Zhao, Chang-Sheng

    2015-11-20

    Post-crosslinking as a new strategy to prepare sodium alginate (SA) beads with controllable swelling behavior, pH sensitivity and adsorption capacity was developed by using the solution of glutaraldehyde (GA), acetic acid and hydrochloric acid as the coagulating agent, for which could be used to fabricate polysaccharide beads in a large scale. Fourier transform infrared spectroscopy and thermogravimetric analysis convinced the successful cross-linking of SA by GA. The macro-porous structures of the beads were observed by scanning electron microscopy. Both acetic acid and hydrochloric acid had great effects on the swelling behavior and pH sensitivity of the SA beads. The SA beads could adsorb cationic dye (methylene blue) as high as 572mg/g and other metal ions (Cu(2+), Ag(+) and Fe(3+)). The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm. The large-scale production of SA beads with tunable properties opens a new route to industrially utilize polysaccharide beads in wastewater treatments, intelligent separation and so on. PMID:26344317

  8. 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.

  9. Functional relationship of room temperature and setting time of alginate impression material

    Directory of Open Access Journals (Sweden)

    Dyah Irnawati

    2009-09-01

    Full Text Available Background: Indonesia is a tropical country with temperature variation. A lot of dental clinics do not use air conditioner. The room temperature influences water temperature for mixing alginate impression materials. Purpose: The aim of this study was to investigate the functional relationship of room temperature and initial setting time of alginate impression materials. Methods: The New Kromopan® alginate (normal and fast sets were used. The initial setting time were tested at 23 (control, 24, 25, 26, 27, 28, 29, 30 and 31 degrees Celcius room temperatures (n = 5. The initial setting time was tested based on ANSI/ADA Specification no. 18 (ISO 1563. The alginate powder was mixed with distilled water (23/50 ratio, put in the metal ring mould, and the initial setting time was measured by test rod. Data were statistically analyzed by linear regression (α = 0.05. result: The initial setting times were 149.60 ± 0.55 (control and 96.40 ± 0.89 (31° C seconds for normal set, and 122.00 ± 1.00 (control and 69.60 ± 0.55 (31° C seconds for fast set. The coefficient of determination of room temperature to initial setting time of alginate were R2 = 0.74 (normal set and R2 = 0.88 (fast set. The regression equation for normal set was Y = 257.6 – 5.5 X (p < 0.01 and fast set was Y = 237.7 – 5.6 X (p < 0.01. Conclusions: The room temperature gave high contribution and became a strength predictor for initial setting time of alginates. The share contribution to the setting time was 0.74% for normal set and 0.88% for fast set alginates.

  10. Release of tissue inhibitor of metalloproteinase-2 from alginate microcapsule encapsulating genetically engineered cells

    Directory of Open Access Journals (Sweden)

    Kim YS

    2013-11-01

    Full Text Available Yeon Seong Kim,1,* Young-Il Jeong,2,* Shu-Guang Jin,2 Jian Pei,2 Min Wen,2 In-Young Kim,1 Kyung-Sub Moon,1 Tae-Young Jung,1 Hyang-Hwa Ryu2, Shin Jung1–3 1Department of Neurosurgery, 2Brain Tumor Research Laboratory, 3Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Jeollanam-do, Korea *These authors contributed equally to this work Background: In this study, 293T cells were genetically engineered to secrete tissue inhibitor of metalloproteinase-2 (TIMP2 and encapsulated into alginate microcapsules to continuously release TIMP2 protein. Methods: The anti-invasive potential of the microcapsules was studied in vitro using brain tumor cells. The TIMP2 gene was transfected to 293T cells, and genetically engineered 293TIMP2 cells were encapsulated into alginate microcapsules. Release of TIMP2 protein was detected with Western blot analysis and the anti-invasive potential against U87MG cells was tested using gelatin zymography and a Matrigel assay. Results: Cell viability within the alginate microcapsules was maintained at a cell density of 5 × 106. Because polycationic polymers are helpful for maintaining the mechanical strength of microcapsules with good cell viability, the alginate microcapsules were reinforced with chitosan (0.1% w/v. Expression of TIMP2 protein in cell lysates and secretion of TIMP2 into the conditioned medium was confirmed by Western blot analysis. Alginate microcapsules encapsulating 293TIMP2 cells released TIMP2 protein into the medium efficiently, where the TIMP2 protein participated in degradation of the matrix metalloproteinase-2 enzyme and inhibited invasion of U87MG cells. Conclusion: Alginate microcapsules encapsulating 293TIMP2 cells are promising candidates for anti-invasive treatment of glioma. Keywords: 293T cells, tissue inhibitor of metalloproteinase-2, alginate microcapsule, therapeutic protein

  11. Use of antioxidants substances to protect the hydrocolloids carrageenan, agaran and alginates used in food industry when exposed to radiation; Uso de substancias antioxidantes na resposta a radiacao dos hidrocoloides carragenanas, agaranas e alginatos utilizados na industria alimenticia

    Energy Technology Data Exchange (ETDEWEB)

    Aliste, Antonio Joao

    2006-07-01

    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)

  12. Synthesis and characterization of macroporous alginate-agarose-magnetite cryobeads for their application in uranium sorption from aqueous medium

    International Nuclear Information System (INIS)

    Contamination of water by heavy metals and radionuclides has become an increasing problem to the environment, which affects the agricultural lands, environmental flora and fauna and importantly human health. There is an interest to develop a simple cost effective technology for the separation of heavy metals from aqueous sub-surfaces. We have developed a novel floating polymeric-magnetite cryobead for the sorption of hexavalent uranium from the aqueous medium. The covalently crosslinked alginate-agarose-magnetite (AAM) cryobeads were synthesized by the process of cryogelation at subzero temperature (i.e. -20 ℃). Alginate polymer was selected for the synthesis of cryobead due to the presence of natural ligand (carboxyl), which interacts with uranyl ions. Agarose was used to provide strength and stability to the cryobeads. Using the AAM cryobeads, we have observed upto 97 % uranium adsorption within 30 min at an initial concentration of 100 mg/L uranium. Due to the macroporous architecture of the cryobeads, the adsorption kinetics was increased 3 folds unlike what has been reported in earlier studies. The study on the effect of pH suggests maximum uranium adsorption (qmax) in the range of 4.5 to 5.5. The thermodynamic parameters i.e. variation in entropy (ΔS), enthalpy (ΔH) and Gibbs free energy (ΔG) were calculated which suggest passive endothermic adsorption behaviour up to 50℃. HCl was found to be an efficient eluent for the uranium desorption. Five repeated cycles for desorption of uranium from biosorbent showed 70 % of uranium recovery. These results suggest stability of novel floating magnetite-cryobeads under acidic conditions and reusability with potential for the recovery of uranium from contaminated aqueous subsurfaces

  13. Preparation and Comparative Characterization of Alginate-Made Microcapsules and Microspheres Containing Tomato, Seabuckthorn Juices and Pumpkin Oil

    Directory of Open Access Journals (Sweden)

    Florina Csernatoni

    2015-05-01

    Full Text Available Recent studies have shown the benefits of tomatoes, seabuckthorn juices and pumpkin oil, rich in bioactives with antioxidant capacity, in the prevention of prostate diseases. To stabilize their antioxidant activity, microencapsulation represent a good technological alternative, improving the stability and bioavailability of bioactive molecules ( phenolic derivatives, carotenoids, phytosterols, vitamins.   The aim of the study was to prepare and characterize microspheres and microcapsules based on emulsions made of natural polymers like Natrium alginate mixed with tomato and/or seabuckthorn juices, with or without pumpkin oil.  The viscosity of emulsions, the morphology of microcapsules and microspheres were characterized comparatively and the bioactives were monitored by UV-Vis spectrometry.  In the lipophilic extract there were identified, before and after encapsulation, different classes of compounds, from lipids, to phenolic acid derivatives, flavonoids and carotenoids. Carotenoids were the major components having concentrations from 9.16 up to 19.71 mg/100 g sample. The viscosity of  each emulsion including juices, oil and natrium alginate 2%, before encapsulation, showed differences, dependent on the oil addition and speed of homogenization. The macroscopic and microscopic structure of microspheres and microcapsules were comparatively evaluated. Both microspheres and microcapsules had external diameters  ranging from 750 to 900 μm and the microcapsules’ oily core of 150-180 μm. The results obtained from emulsion’s viscosity will be correlated with the rigidity and optimal release rate of bioactive molecules from microcapsules and microspheres.  Further studies are directed towards these aspects.

  14. 海藻酸盐与异种骨构建组织工程载体的适宜浓度%Suitable concentration of alginate with xenograft for constructing bone tissue engineering carrier

    Institute of Scientific and Technical Information of China (English)

    孙磊; 孟国林; 窦榆生; 徐建强; 刘丹平; 胡蕴玉

    2007-01-01

    University of Chinese PLA.MATERIALS: Alginate, calcium chloride, MSCs, bone xenograft.METHODS: Bovine cancellous bone was out into cubes, which were degreased, deproteinized and then lyophilized.Cubes in pore size within 300-500 μm were selected for use after ethylene oxide sterilization. The purified sodium alginate was dissolved in DMEM cell culture medium of concentrations as different as 0.5%, 2%, 8% and 16%; 1×1012 L-1 induced MSCs were blended with isopyknic alginate-DMEM and compounded with DBX at a status of 0.5 Mpa negative pressure for 5 minutes in order to make a cell suspension fully fill into the pores of the cancellous bone. Then alginate was crosslinked with 50 g/L calcium gluconic acid for 30 seconds. The complex was put into a CO2 incubator and cultured for 4 days. The gel compound and cell growth in the pores of the complex were grossly observed with an inverted microscope. Status of cell growth in the complex with different concentrations of alginate was observed with scanning electron microscopeMAIN OUTCOME MEASURES: Compound status of alginate and bone xenograft, cell growth status and matrix secretion in compound carries.RESULTS: When the concentration of alginate was 0.25% or 1%, alginate was equally combined in DBX, while that of 4% and 8% only combined on the surface of cancellous bone. After in vitro cultured for 4 days, alginate of 0.25% were broken off from DBX surface. But alginate of 1% was equally combined with DBX pores with cells secreting well in alginate. Development of cells in alginate of 4% was restricted and no cells were seen in alginate of 8%.CONCLUSION: Alginate of 1% is suitable for constructing the carrier of bone tissue engineering with bone xenograft.

  15. 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)

  16. 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

  17. Facile fabrication of organic-inorganic hybrid beads by aminated alginate enabled gelation and biomimetic mineralization.

    Science.gov (United States)

    Li, Jian; Wu, Hong; Liang, Yanpeng; Jiang, Zhongyi; Jiang, Yanjun; Zhang, Lei

    2013-01-01

    Inspired by biomineralization, design and preparation of biomimetic organic-inorganic composites have become a hot issue and a research frontier in many areas, including enzyme engineering. In this research, a unique and facile method for fabricating organic-inorganic hybrid beads is proposed. Modified alginate with a dual function of gelation and mineralization was synthesized for fabrication of hybrid carriers for enzyme immobilization. With the aid of EDC/NHS conjugation chemistry, the amine groups from diethylene triamine were grafted onto alginate in a controllable way. The resultant aminated alginate served manifold functions: forming a hydrogel via Ca(2+)-cross-linking, inducing the biomimetic silicification and manipulating the distribution of silica nanoparticles. Owing to the compact polymer network structure and the homogeneous silica nanoparticle dispersion, the as-prepared NH2-alginate/silica hybrid beads displayed superior swelling resistance and mechanical stability to pure alginate beads. The hybrid beads were subsequently utilized for encapsulation of yeast alcohol dehydrogenase (YADH). It was found that the thermal stability, pH tolerance and storage stability of the immobilized enzyme were all improved without significantly lowering the catalytic activity.

  18. 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

  19. 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

  20. 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.

  1. Purification and characterization of alginate lyase from locally isolated marine Pseudomonas stutzeri MSEA04.

    Science.gov (United States)

    Beltagy, Ehab A; El-Borai, Aliaa; Lewiz, Marina; ElAssar, Samy A

    2016-09-01

    An alginate lyase with high specific enzyme activity was purified from Pseudomonas stutzeri MSEA04, isolated from marine brown algae. The alginate lyase was purified by precipitation with ammonium sulphate, acetone and ethanol individually. 70% ethanol fraction showed maximum specific activity (133.3 U/mg). This fraction was re-purified by anion exchange chromatography DEAE- Cellulose A-52. The loaded protein was separated into 3 peaks. The second protein peak was the major one which contained 48.2% of the total protein recovered and 79.4% of the total recovered activity. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. Alginate lyase activity was fractionated in the Sephadex column into one major peak, and the specific activity of this fraction reached 116 U/mg. The optimal substrate concentration, pH and temperature for alginate lyase activity were 8 mg/ml, pH 7.5 and 37 °C, respectively. While, Km and Vmax values were 1.07 mg alginate/ ml and 128.2 U/mg protein, respectively. The enzyme was partially stable below 50 °C, and the activity of the enzyme was strongly enhanced by K(+), and strongly inhibited by Ba(+2), Cd(+2), Fe(+2) and Zn(+2). The purified enzyme yielded a single band on SDS-PAGE with molecular weight (40.0 kDa). PMID:27630053

  2. 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.

  3. 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.

  4. Insights in Behavior of Variably Formulated Alginate-Based Microcapsules for Cell Transplantation

    Directory of Open Access Journals (Sweden)

    Pia Montanucci

    2015-01-01

    Full Text Available Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation, in vitro and in vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.

  5. Synthesis and characterisation of alginate/chitosan nanoparticles as tamoxifen controlled delivery systems.

    Science.gov (United States)

    Martínez, A; Arana, P; Fernández, A; Olmo, R; Teijón, C; Blanco, M D

    2013-01-01

    Polysaccharides have shown ideal features for their application in nanomedicine as nanoparticulated systems. Nanoparticles based on mixtures of alginate and chitosan (A/Q-50/50, formed by 50% alginate and 50% chitosan, and A/Q-70/30, formed by 70% alginate and 30% alginate) have been synthesised by an emulsification method and stabilised by amide bond formation. Tamoxifen (TMX) was loaded into these systems, and they were assayed as controlled delivery formulations. Results showed the formation of spherical nanoparticles with very small size (19-28 nm). The presence of amide bonds was determined by FT-IR and confirmed by Thermogravimetric analysis studies. TMX incorporation was achieved successfully (2-3 µg TMX per mg NP), and maximum TMX release took place between 8 and 24 h. This study shows that interaction between TMX and the system was dependent on nanoparticle composition, being the composition with higher proportion of alginate the one which showed the best release control of the drug. PMID:23489017

  6. Effects of alginate hydrogel cross-linking density on mechanical and biological behaviors for tissue engineering.

    Science.gov (United States)

    Jang, Jinah; Seol, Young-Joon; Kim, Hyeon Ji; Kundu, Joydip; Kim, Sung Won; Cho, Dong-Woo

    2014-09-01

    An effective cross-linking of alginate gel was made through reaction with calcium carbonate (CaCO3). We used human chondrocytes as a model cell to study the effects of cross-linking density. Three different pore size ranges of cross-linked alginate hydrogels were fabricated. The morphological, mechanical, and rheological properties of various alginate hydrogels were characterized and responses of biosynthesis of cells encapsulated in each gel to the variation in cross-linking density were investigated. Desired outer shape of structure was maintained when the alginate solution was cross-linked with the applied method. The properties of alginate hydrogel could be tailored through applying various concentrations of CaCO3. The rate of synthesized GAGs and collagens was significantly higher in human chondrocytes encapsulated in the smaller pore structure than that in the larger pore structure. The expression of chondrogenic markers, including collagen type II and aggrecan, was enhanced in the smaller pore structure. It was found that proper structural morphology is a critical factor to enhance the performance and tissue regeneration.

  7. Mechanisms and factors affecting the adsorption of sodium alginate onto modified clays

    Institute of Scientific and Technical Information of China (English)

    LIN Yongxin; CAO Xihua; SONG Xiuxian; WANG Nan; YU Zhiming

    2013-01-01

    Algal organic materials (AOMs) are one critical factor affecting the efficiency of modified clays used for the mitigation of harmful algal blooms (HABs).This study was conducted to develop a deeper understanding of the mechanisms and factors affecting the adsorption of AOMs onto modified clays.Sodium alginate (polysaccharide) and kaolinite modified with polyaluminium chloride (PAC1) were used as AOMs and modified clay model substances,respectively,and the effects of modifier dosage,contact time,solution pH and ionic strength were investigated through batch adsorption experiments.Kinetics revealed that the alginate adsorption rate was described well by a pseudo-second order model.PAC1 effectively enhanced the adsorption capacity of kaolinite and increased the adsorption rate,and the optimum additive amount of PAC1 was 5%.The experimental data fitted both the Freundlich and Langmuir adsorption equations well.The adsorption thermodynamics for alginate onto modified clays suggests that alginate adsorption is a spontaneous process.The adsorption of alginate onto modified clays was highly dependent on pH,with a decrease in adsorption observed with increased pH to 9.48,but the opposite was true above pH 9.48.Finally,adsorption increased with increasing ionic strength.

  8. Tough Al-alginate/poly(N-isopropylacrylamide) hydrogel with tunable LCST for soft robotics.

    Science.gov (United States)

    Zheng, Wen Jiang; An, Ning; Yang, Jian Hai; Zhou, Jinxiong; Chen, Yong Mei

    2015-01-28

    Tough Al-alginate/poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been synthesized by introducing an interpenetrating network with hybrid physically cross-linked alginate and chemically cross-linked PNIPAM. Varying the concentration of AlCl3 regulates the mechanical properties of the tough hydrogel and tunes its lower critical solution temperature (LCST) as well. The tough Al-alginate/PNIPAM exhibits 6.3 ± 0.3 MPa of compressive stress and 9.95 of uniaxial stretch. Tunability of LCST is also achieved in a wide range within 22.5-32 °C. A bending beam actuator and a four-arm gripper made of bilayer (Na-alginate/PNIPAM)/(Al-alginate/PNIPAM) hydrogel as prototype of all-hydrogel soft robotics are demonstrated. A finite element (FE) simulation model is developed to simulate the deformation of the soft robotics. The FE simulation not only reproduces the deformation process of performed experiments but also predicts more complicated devices that can be explored in the future. This work broadens the application of temperature-responsive PNIPAM-based hydrogels.

  9. 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.

  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. Biocompatible Double-Membrane Hydrogels from Cationic Cellulose Nanocrystals and Anionic Alginate as Complexing Drugs Codelivery.

    Science.gov (United States)

    Lin, Ning; Gèze, Annabelle; Wouessidjewe, Denis; Huang, Jin; Dufresne, Alain

    2016-03-23

    A biocompatible hydrogel with a double-membrane structure is developed from cationic cellulose nanocrystals (CNC) and anionic alginate. The architecture of the double-membrane hydrogel involves an external membrane composed of neat alginate, and an internal composite hydrogel consolidates by electrostatic interactions between cationic CNC and anionic alginate. The thickness of the outer layer can be regulated by the adsorption duration of neat alginate, and the shape of the inner layer can directly determine the morphology and dimensions of the double-membrane hydrogel (microsphere, capsule, and filmlike shapes). Two drugs are introduced into the different membranes of the hydrogel, which will ensure the complexing drugs codelivery and the varied drugs release behaviors from two membranes (rapid drug release of the outer hydrogel, and prolonged drug release of the inner hydrogel). The double-membrane hydrogel containing the chemically modified cellulose nanocrystals (CCNC) in the inner membrane hydrogel can provide the sustained drug release ascribed to the "nano-obstruction effect" and "nanolocking effect" induced by the presence of CCNC components in the hydrogels. Derived from natural polysaccharides (cellulose and alginate), the novel double-membrane structure hydrogel material developed in this study is biocompatible and can realize the complexing drugs release with the first quick release of one drug and the successively slow release of another drug, which is expected to achieve the synergistic release effects or potentially provide the solution to drug resistance in biomedical application.

  12. The promoting effects of alginate oligosaccharides on root development in Oryza sativa L. mediated by auxin signaling.

    Science.gov (United States)

    Zhang, Yunhong; Yin, Heng; Zhao, Xiaoming; Wang, Wenxia; Du, Yuguang; He, Ailing; Sun, Kegang

    2014-11-26

    Alginate oligosaccharides (AOS), which are marine oligosaccharides, are involved in regulating plant root growth, but the promotion mechanism for AOS remains unclear. Here, AOS (10-80 mg/L) induced the expression of auxin-related gene (OsYUCCA1, OsYUCCA5, OsIAA11 and OsPIN1) in rice (Oryza sativa L.) tissues to accelerate auxin biosynthesis and transport, and reduced indole-3-acetic acid (IAA) oxidase activity in rice roots. These changes resulted in the increase of 37.8% in IAA concentration in rice roots, thereby inducing the expression of root development-related genes, promoting root growth in a dose-dependent manner, which were inhibited by auxin transport inhibitor 2,3,5-triiodo benzoic acid (TIBA) and calcium-chelating agent ethylene glycol bis (2-aminoethyl) tetraacetic acid (EGTA). AOS also induced calcium signaling generation in rice roots. Those results indicated that auxin mediated AOS regulation of root development, and calcium signaling may act mainly in the upstream of auxin in the regulation of AOS on rice root development. PMID:25256506

  13. Anaerobic digestion of waste sludges from the alginate extraction process

    Energy Technology Data Exchange (ETDEWEB)

    Kerner, K.N.; Hanssen, J.F.; Pedersen, T.A. (Agricultural Univ. of Norway, Aas (NO). Dept. of Biological Sciences)

    1991-01-01

    Anaerobic digestion of waste sludges produced during the industrial extraction of alginate from the algal species Laminaria hyperborea (Gunn.) Foslie and Ascophyllum nodosum (L.) Le Jol was studied. Experiments were carried out in bench scale (8-litre) intermittently stirred digesters at 35{sup o}C. Sieve and flotation sludges were digested in batch (1 month) and semi-continuous cultures. In the semi-continuous trials, retention times of 23 days and 16 days were tested. Methane production varied from 0.10 to 0.15 litre g{sup -1} volatile solids (VS) added during batch; and from 0.07 to 0.28 litre g{sup -1} VS added during semi-continuous fermentation. Specific gas production was significantly higher at 23 days than at 16 days retention time. VS reductions were 20-40% (batch) and 40-50% (semi-continuous). A distinct improvement of the settling qualities of digester effluents was obtained during the anaerobic digestion process. (author).

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. Alginate-hyaluronan composite hydrogels accelerate wound healing process.

    Science.gov (United States)

    Catanzano, O; D'Esposito, V; Acierno, S; Ambrosio, M R; De Caro, C; Avagliano, C; Russo, P; Russo, R; Miro, A; Ungaro, F; Calignano, A; Formisano, P; Quaglia, F

    2015-10-20

    In this paper we propose polysaccharide hydrogels combining alginate (ALG) and hyaluronan (HA) as biofunctional platform for dermal wound repair. Hydrogels produced by internal gelation were homogeneous and easy to handle. Rheological evaluation of gelation kinetics of ALG/HA mixtures at different ratios allowed understanding the HA effect on ALG cross-linking process. Disk-shaped hydrogels, at different ALG/HA ratio, were characterized for morphology, homogeneity and mechanical properties. Results suggest that, although the presence of HA does significantly slow down gelation kinetics, the concentration of cross-links reached at the end of gelation is scarcely affected. The in vitro activity of ALG/HA dressings was tested on adipose derived multipotent adult stem cells (Ad-MSC) and an immortalized keratinocyte cell line (HaCaT). Hydrogels did not interfere with cell viability in both cells lines, but significantly promoted gap closure in a scratch assay at early (1 day) and late (5 days) stages as compared to hydrogels made of ALG alone (phydrogels significantly promoted wound closure as compared to ALG ones (phydrogel can be a versatile strategy to promote wound healing that can be easily translated in a clinical setting.

  1. 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

  2. Alginate submicron beads prepared through w/o emulsification and gelation with CaCl2 nanoparticles

    NARCIS (Netherlands)

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

    2013-01-01

    A simple method for preparing gelled alginate beads with a diameter smaller than 5 µm is described. A 1% alginate solution and a medium chain triglyceride (MCT) oil are used to prepare a water-in-oil (w/o) emulsion, stabilized by polyglycerol polyricinoleate. CaCl2 nanoparticles with dimensions in t

  3. Macrophage depletion improves survival of porcine neonatal pancreatic cell clusters contained in alginate macrocapsules transplanted into rats

    NARCIS (Netherlands)

    Omer, A; Keegan, M; Czismadia, E; De Vos, P; Van Rooijen, N; Bonner-Weir, S; Weir, GC

    2003-01-01

    Background: Macrophages can accumulate on the surface of empty and islet-containing alginate capsules, leading to loss of functional tissue. In this study, the effect of peritoneal macrophage depletion on the biocompatibility of alginate macrocapsules and function of macroencapsulated porcine neonat

  4. Macrophage depletion improves survival of porcine neonatal pancreatic cell clusters contained in alginate macrocapsules transplanted into rats.

    NARCIS (Netherlands)

    Omer, A; Keegan, M; Czismadia, E; Vos, P De; Rooijen, van N.; Bonner-Weir, S; Weir, GC

    2003-01-01

    BACKGROUND: Macrophages can accumulate on the surface of empty and islet-containing alginate capsules, leading to loss of functional tissue. In this study, the effect of peritoneal macrophage depletion on the biocompatibility of alginate macrocapsules and function of macroencapsulated porcine neonat

  5. 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

  6. Effect of Alginate Film Containing Cinnamon and Nisin on the Freshness of Northern Snakehead%含肉桂油和Nisin的海藻酸钠薄膜保鲜黑鱼性能分析水

    Institute of Scientific and Technical Information of China (English)

    吕飞; 丁玉庭; 叶兴乾

    2011-01-01

    Alginate-calcium film that contains cinnamon oil and nisin was used as an antimicrobial packaging to maintain the freshness of northern snakehead at refrigeration temperature (4 ± 1 ) °C . Northern snakehead fillets were treated with alginate film ( CO) , and alginate film contained cinnamon oil ( Cl) , alginate film containing Nisin ( C2 ) , or alginate film containing cinnamon oil and Nisin ( C3 ). Northern snakehead fillets without any treatment were used as a control(CK) . Cl and C3 more efficiently inhibited the growth of total viable mesophilic bacteria, total psychrotrophs bacteria and Pseudomonas spp. Than CK, CO and C2 treatments. Cl and C3 treatments significantly reduced chemical spoilage, reflected in low pH value, total volatile base nitrogen content and thiobarbituric acid reactive substances, and retarded color changes. However, there was no significant difference between the Cl and C3 treatments. Thus, alginate-calcium film containing cinnamon or cinnamon and Nisin efficiently maintained the quality of northern snakehead fillets during storage.%研究了含有肉桂油和Nisin的海藻酸钠抗菌薄膜保鲜(4±1)℃下贮藏黑鱼鱼肉的效果.鱼肉片被分为:未处理组(CK),海藻酸钠薄膜组(C0),肉桂油海藻酸钠薄膜组(C1),Nisin海藻酸钠薄膜组(C2),肉桂油和Nisin海藻酸钠薄膜组(C3).相对于CK、C0和C2,C1和C3能更好抑制鱼肉总嗜温菌、总嗜冷菌和假单胞菌.C1和C3可显著抑制鱼肉的腐败变质,维持较低pH值、挥发性盐基氮含量和脂肪氧化值,并能抑制鱼肉色泽的变化.C1和C3在维持鱼肉品质上无显著差异.因此,含有肉桂油或者肉桂油和Nisin的海藻酸钠薄膜可有效维持黑鱼的贮藏品质.

  7. 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.

  8. Sodium alginate microneedle arrays mediate the transdermal delivery of bovine serum albumin.

    Directory of Open Access Journals (Sweden)

    Yusuf K Demir

    Full Text Available 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 needle free patches using two different analytical methods. METHODOLOGY AND FINDINGS: The capability of two analytical methods, the bicinchoninic acid (BCA assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE, to precisely detect and quantify BSA within different types of polymeric MNs was assessed. The ex vivo protein release of BSA across dermatomed human abdominal skin from 10 w/w SA MNs was compared to that from needle-free patches using Franz diffusion cells. The developed applicator was mechanically characterized using a Texture Analyzer. The patch mold and its components were fabricated using a rapid prototyping machine. CONCLUSIONS/SIGNIFICANCE: The BCA method was able to precisely detect BSA that had been loaded into SA MNs. However, the use of SDS-PAGE as the analytical method resulted in significantly different amounts of BSA recovered from differently conditioned polymeric MNs. The permeation of BSA across dermatomed human abdominal skin by SA MNs, which were composed of 100 pyramidal needles, increased by approximately 15.4 fold compared to the permeation obtained with SA needle-free patches. The ease of use of the applicator during the release studies was also demonstrated, as was its mechanical characterization.

  9. Release of insulin from PLGA-alginate dressing stimulates regenerative healing of burn wounds in rats.

    Science.gov (United States)

    Dhall, Sandeep; Silva, João P; Liu, Yan; Hrynyk, Michael; Garcia, Monika; Chan, Alex; Lyubovitsky, Julia; Neufeld, Ronald J; Martins-Green, Manuela

    2015-12-01

    Burn wound healing involves a complex set of overlapping processes in an environment conducive to ischaemia, inflammation and infection costing $7.5 billion/year in the U.S.A. alone, in addition to the morbidity and mortality that occur when the burns are extensive. We previously showed that insulin, when topically applied to skin excision wounds, accelerates re-epithelialization and stimulates angiogenesis. More recently, we developed an alginate sponge dressing (ASD) containing insulin encapsulated in PLGA [poly(D,L-lactic-co-glycolic acid)] microparticles that provides a sustained release of bioactive insulin for >20 days in a moist and protective environment. We hypothesized that insulin-containing ASD accelerates burn healing and stimulates a more regenerative, less scarring healing. Using heat-induced burn injury in rats, we show that burns treated with dressings containing 0.04 mg insulin/cm(2) every 3 days for 9 days have faster closure, a higher rate of disintegration of dead tissue and decreased oxidative stress. In addition, in insulin-treated wounds, the pattern of neutrophil inflammatory response suggests faster clearing of the burned dead tissue. We also observe faster resolution of the pro-inflammatory macrophages. We also found that insulin stimulates collagen deposition and maturation with the fibres organized more like a basket weave (normal skin) than aligned and cross-linked (scar tissue). In summary, application of ASD-containing insulin-loaded PLGA particles on burns every 3 days stimulates faster and more regenerative healing. These results suggest insulin as a potential therapeutic agent in burn healing and, because of its long history of safe use in humans, insulin could become one of the treatments of choice when repair and regeneration are critical for proper tissue function.

  10. Drug–polymer interaction between glucosamine sulfate and alginate nanoparticles: FTIR, DSC and dielectric spectroscopy studies

    Science.gov (United States)

    El-Houssiny, A. S.; Ward, A. A.; Mostafa, D. M.; Abd-El-Messieh, S. L.; Abdel-Nour, K. N.; Darwish, M. M.; Khalil, W. A.

    2016-06-01

    This work involves the preparation and characterization of alginate nanoparticles (Alg NPs) as a new transdermal carrier for site particular transport of glucosamine sulfate (GS). The GS–Alg NPs were examined through transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and dielectric spectroscopy. GS–Alg NPs was efficiently prepared via ionic gelation method which generates favorable conditions for the entrapment of hydrophilic drugs. The TEM studies revealed that GS–Alg NPs are discrete and have spherical shapes. FTIR studies showed a spectral change of the characteristic absorptions bands of Alg NPs after encapsulation with GS because of the amine groups of GS and the carboxylic acid groups of Alg. The DSC data showed changes in the thermal behavior of GS–Alg NPs after the addition of GS indicating signs of main chemical interaction among the drug (GS) and the polymer (Alg). The absence of the drug melting endothermic peak within the DSC thermogram of GS–Alg NPs indicating that GS is molecularly dispersed in the NPs and not crystallize. From the dielectric study, it was found modifications within the dielectric loss (ε″) and conductivity (σ) values after the addition of GS. The ε″ and σ values of Alg NPs decreased after the addition of GS which indicated the successful encapsulation of GS within Alg NPs. Furthermore, the dielectric study indicated an increase of the activation energy and the relaxation time for the first process in the GS–Alg NPs as compared to Alg NPs. Consequently, the existing observations indicated an initiation of electrostatic interaction among the amine group of GS and carboxyl group of Alg indicating the successful encapsulation of GS inside Alg NPs which could provide favorable circumstance for the encapsulation of GS for topical management.

  11. PIXE study on inhibition effect of sodium alginate to the absorption of strontium

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xinpei [Academia Sinica, Beijing, BJ (China). Inst. of Atomic Energy

    1992-12-31

    The sodium alginate extracted from sargassum of South China Sea significantly inhibited the absorption of Sr in human gastrointestinal tract. Because of the identical metabolism dynamics of radioactive Sr and stable Sr, oral medication experiments have been performed by using stable Sr as a tracer. Fifteen adult healthy subjects (10 males and 5 females) were involved and divided into two groups. Concentrations of Sr, Ca, Fe, Cu, and Zn in serum and urine (24 hours) at different times after oral medications were measured by PIXE. It was found from the PIXE results that Sr in serum and in urine were reduced (78 +/- 8.9)% and (78 +/- 11)% respectively by sodium alginate. A reasonable dosage of sodium alginate had little influence to the absorption of Ca, Fe, Cu, and Zn. (author).

  12. 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......-overproducing (mucA22) and alginate-defective (algD) variants in order to discern the role of alginate in biofilm formation. These strains, PAO1, Alg(+) PAOmucA22 and Alg(-) PAOalgD, tagged with green fluorescent protein, were grown in a continuous flow cell system to characterize the developmental cycles...... of their 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...

  13. 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.

  14. 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

  15. 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.

  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. 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

  18. 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

  19. Antimicrobial Effects of Silver Nanoparticles Stabilized in Solution by Sodium Alginate

    Science.gov (United States)

    Kubyshkin, Anatoliy; Chegodar, Denis; Katsev, Andrew; Petrosyan, Armen; Krivorutchenko, Yuri; Postnikova, Olga

    2016-01-01

    Background/purpose To investigate the effect of nanosilver particles in solution stabilized in a matrix of sodium alginate on the growth and development of pathogenic bacteria such as Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Proteus vulgaris, Enterobacter cloacae, the antibiotic-resistant strain of Pseudomonas aeruginosa, the yeast-like fungus Candida albicans, and the luminescent bacteria Photobacterium leiognathi Sh1. Methods Isolates of pathogenic bacteria obtained from bronchoalveolar and peritoneal lavage samples from Wistar rats with experimental pneumonia and peritonitis were tested for their susceptibility to silver nanoparticles in solution with an alginate stabilizer. The antifungal activity of silver nanoparticles in sodium alginate was studied for C. albicans (strain CCM885) using the Sabouraud agar method. The biocidal impact of silver nanoparticles in solution with a sodium alginate matrix on the luminescent bacteria P. leiognathi Sh1 was investigated using a BLM 8801 luminometer. Results It was observed that a 0.02-0.05% nanosilver solution with an alginate stabilizer limits the growth and development of pathogenic bacteria within the first 24 hours of exposure. If the concentration of nanosilver solution is 0.0005-0.05%, it inhibits the viability of the fungus C. albicans. A nanosilver solution at a concentration of 0.05-0.2 μg/mL represses bioluminescence in the bacteria P. leiognathi Sh1. From these results, it appears that the biocidal effect of nanosilver is related either to the presence of ions that are formed during dissolution, or to the availability of nanoparticles that interrupt the membrane permeability of bacterial cells. Conclusion Silver nanoparticles stabilized in a solution of sodium alginate possess significant in vitro antimicrobial activity, which is manifested by inhibition of the bioluminescence of P. leiognathi Sh1, and inhibition of the growth and development of the pathogenic bacteria S. aureus, E

  20. 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.

  1. Improving the quality of Laminaria japonica-based diet for Apostichopus japonicus through degradation of its algin content with Bacillus amyloliquefaciens WB1.

    Science.gov (United States)

    Wang, Xitao; Wang, Lili; Che, Jian; Li, Zhen; Zhang, Jiancheng; Li, Xiaoyu; Hu, Weiqing; Xu, Yongping

    2015-07-01

    Laminaria japonica feedstuff is used as a substitute for Sargassum thunbergii in the small-scale culturing of Apostichopus japonicus (sea cucumber) because of its abundant sources and low price in China. However, the difficulty associated with the degradation of algin by A. japonicus and, hence, its utilization have limited the practical value of L. japonica feedstuff in sea cucumber farming. In this study, A. japonicus individuals were fed with L. japonica feedstuff pretreated, via fermentation with the algin-degrading bacterial strain, Bacillus amyloliquefaciens WB1, and their growth performance, nonspecific immune responses, and resistance against Vibrio infection were then determined over a 60-day period. Growth performance of these individuals was similar to those fed with a commercial feedstuff made from S. thunbergii (mean weight gain of 5.79 versus 5.69 g on day 60), but was significantly (P < 0.05) increased compared to those fed with untreated L. japonica feedstuff (mean weight gain of 1.31 g). At the same time, they also showed significantly higher levels of amylase, protease, and alginate lyase activities than the other groups. These individuals and those fed with the commercial feedstuff or heat-inactivated but B. amyloliquefaciens WB1-treated L. japonicas feedstuff showed enhanced levels of activities for the immune enzymes nitric oxide synthase, lysozyme, peroxidase, and acid phosphatase, compared to those fed with nontreated L. japonica feedstuff. Furthermore, A. japonicus individuals fed with B. amyloliquefaciens WB1-treated L. japonica feedstuff exhibited greater resistance to disease following Vibrio splendidus challenge, as shown by the much lower cumulative symptom (10 %) compared to the rest, which showed as much as 73 % in the case of individuals fed with the untreated L. japonica feedstuff. Analysis of their intestinal tract revealed a much lower number of total Vibrio sp. These results demonstrated that L. japonica in which the algin

  2. An in vitro study of the antiviral properties of an alginate impression material impregnated with disinfectant.

    Science.gov (United States)

    Tyler, R; Tobias, R S; Ayliffe, G A; Browne, R M

    1989-06-01

    The antiviral properties of a new alginate impression material impregnated with a disinfectant (didecyldimethyl ammonium chloride) were evaluated in vitro against herpes simplex virus type I and poliovirus type I. The material was exposed to the virus suspension for periods of up to 60 min. The impregnated alginate material showed no clinically acceptable effect against either virus, although log reductions of 1.0 and 1.7 plaque-forming units of herpes virus were obtained after exposure to the material containing the disinfectant for 5 and 60 min, respectively.

  3. 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...

  4. 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...

  5. An in vitro study of the antiviral properties of an alginate impression material impregnated with disinfectant.

    Science.gov (United States)

    Tyler, R; Tobias, R S; Ayliffe, G A; Browne, R M

    1989-06-01

    The antiviral properties of a new alginate impression material impregnated with a disinfectant (didecyldimethyl ammonium chloride) were evaluated in vitro against herpes simplex virus type I and poliovirus type I. The material was exposed to the virus suspension for periods of up to 60 min. The impregnated alginate material showed no clinically acceptable effect against either virus, although log reductions of 1.0 and 1.7 plaque-forming units of herpes virus were obtained after exposure to the material containing the disinfectant for 5 and 60 min, respectively. PMID:2549107

  6. Evaluation of dyes adsorption properties of TiO2-alginate biohybrid material

    Science.gov (United States)

    Barrón Zambrano, J. A.; Sánchez Morales, G.; Ávila Ortega, A.; Muñoz Rodríguez, D.; Carrera Figueiras, C.

    2013-06-01

    In this study a TiO2-alginate biohybrid material was obtained by the sol gel method and its adsorption properties were compared to those of its precursors using eosin B (anionic) as model dye. The results showed that the TiO2 and biohybrid have a greater affinity for eosine B than alginate. The maximum adsorption capacity for the eosin B was obtained at pH = 10. Kinetic studies showed that the biohybrid has greater rate and adsorption capacity than its precursors. Kinetic data were fitted to a pseudo-second order kinetic model. The experimental isotherms were fitted to the Langmuir model.

  7. Radiation effects on agar, alginates and carrageenan to be used as food additives

    Science.gov (United States)

    Aliste, A. J. A. J.; Vieira, F. F. F. F.; Del Mastro, N. L. N. L.

    2000-03-01

    Agar, alginates and carrageenan are hydrocolloids that induce stabilization of physical properties of the food product during shelf life and prevention of undesirable changes such as moisture migration, gas cell coalescence or textural profile changes. In this work, agar, alginates and carrageenan was irradiated as powder with different doses (0-10 kGy) of Co-60 and the rheological functional performance of water solutions of these irradiated additives was studied. The results are analyzed taking in account the future applications of those additives in irradiated foods.

  8. Effect of alginate/carboxyl methyl cellulose composite coating incorporated with clove essential oil on the quality of silver carp fillet and Escherichia coli O157:H7 inhibition during refrigerated storage.

    Science.gov (United States)

    Jalali, Nastaran; Ariiai, Peiman; Fattahi, Esmaeil

    2016-01-01

    The effects of alginate/carboxyl methylcellulose composite coating incorporated with clove essential oil on quality of silver carp fillet chilled storage (4 + 1 °C) were examined over a period of 16 days. The control samples (c), alginate/carboxyl methylcellulose coating (C-A), alginate/carboxyl methylcellulose composite coating incorporated with clove essential oil (with different concentration 1 and 1.5 %) (C-A + CEO1 % and C-A + CEO 15 % respectively) were analyzed by bacteriological (total viable counts (TVC) and total psychrotrophic counts (TPC)), biochemical (Peroxide value (PV), free fatty acid (FFA), total volatile base nitrogen (TVB-N), and pH) and sensory characteristics. Also, the efficacy of these treatments was investigated in control of the population of Eschershia coli O157:H7 inoculated in silver carp fillet. According to the obtained results, C-A + CEO 1.5 % showed lowest (p clove essential oil might be recommended as a preservative in the meat products. PMID:26787996

  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. Bioluminescence tracking of alginate micro-encapsulated cell transplants.

    Science.gov (United States)

    Tiernan, Aubrey R; Sambanis, Athanassios

    2014-07-22

    Cell-based therapies to treat loss-of-function hormonal disorders such as diabetes and Parkinson's disease are routinely coupled with encapsulation strategies, but an understanding of when and why grafts fail in vivo is lacking. Consequently, investigators cannot clearly define the key factors that influence graft success. Although bioluminescence is a popular method to track the survival of free cells transplanted in preclinical models, little is known of the ability to use bioluminescence for real-time tracking of microencapsulated cells. Furthermore, the impact that dynamic imaging distances may have, due to freely-floating microcapsules in vivo, on cell survival monitoring is unknown. This work addresses these questions by applying bioluminescence to a pancreatic substitute based on microencapsulated cells. Recombinant insulin-secreting cells were transduced with a luciferase lentivirus and microencapsulated in Ba(2+) crosslinked alginate for in vitro and in vivo studies. In vitro quantitative bioluminescence monitoring was possible and viable microencapsulated cells were followed in real time under both normoxic and anoxic conditions. Although in vivo dispersion of freely-floating microcapsules in the peritoneal cavity limited the analysis to a qualitative bioluminescence evaluation, signals consistently four orders of magnitude above background were clear indicators of temporal cell survival. Strong agreement between in vivo and in vitro cell proliferation over time was discovered by making direct bioluminescence comparisons between explanted microcapsules and parallel in vitro cultures. Broader application of this bioluminescence approach to retrievable transplants, in supplement to currently used end-point physiological tests, could improve understanding and accelerate development of cell-based therapies for critical clinical applications. Copyright © 2014 John Wiley & Sons, Ltd.

  11. 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;}

  12. 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.

  13. Immobilized Lactobacillus acidophilus produced from whey and alginate

    Directory of Open Access Journals (Sweden)

    P. R. Rosa

    2013-06-01

    Full Text Available An analysis was made of the use of whey fermentation by Lactobacillus acidophilus LA-5 for encapsulated probiotic bacteria cell production. Fermentation was done in a 2-liter Biostat B Fermentor at 28±1 ºC without air supply and agitation maintained at 200 rpm. Different processing conditions were studied using Center Composite Design applied to Surface Response Methodology. Maximum cell yield (2.7 x10(10 NMP/mL for 36 hours was achieved with 30.85 g/L of lactose, a pH value of 6.45 and 1.04 g/L of inoculum. Cell growth was evaluated using reconstituted and fresh whey after 144 hours of fermentation in pre-optimized conditions. Cell concentration after fermentation was 10(10 MPN/mL in all the assays. The Verhulst model proved to be satisfactory to fit the experimental results, providing a stationary cell concentration of 6.0 g/L and a specific growth rate of 0.09 h-1. Cells were collected by centrifugation at 15000g for 5 minutes at 4 ºC, immobilized in 2% alginate, and dried to a constant weight at 50 ºC. Immobilized probiotic cells presented 10(11 MPN/g, a time required to kill 90% of the organisms (D value of 18 h (70 ºC, an activation energy of 76.04 kJ/mol for thermal inactivation, and an in vitro resistance to low pH (D value of 62.5 min at 37 ºC, pH 2.5.

  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. 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

  16. The effect of alginate impressions on the surface of cast gypsum. II. The role of sodium sulphate in incompatibility.

    Science.gov (United States)

    Jarvis, R G; Earnshaw, R

    1981-02-01

    Of the materials tested only two alginates, Palginex (D), and Echo (C), show good surface reproduction when Vel-Mix (1), Ainsworth Greenstone (4), and Investo Greenstone (5) are cast against them. The above two alginates were shown to have a potassium and sulphate rich exudate. The reasonable surface produced by CA-37 (A) can be attributed to a proportional decrease in the ratio of potassium to sulphate present in the exudate, compared with Echo (C) and Palginex (D). S.S. White (B), Kromopan (E), and Tissutex (G) produce poor cast surfaces when high strength gypsum products are set against them. The exudates from these alginates were found to consist almost entirely of sodium sulphate. This study suggests that one way to improve the surface compatibility of alginates with gypsum products would be to modify the chemistry of the impression material so that a reactor other than calcium sulphate is used, to eliminate the appearance of sulphate ions in the exudate. Moreover, sources of sodium ions should also be eliminated. Therefore soluble alginates other than sodium alginate should be preferred, and a retarder other than one or other of the forms of sodium phosphate should be used. These changes would ensure that sulphate, particularly sodium sulphate, would not be produced as a by-product of the setting reaction. This in turn would eliminate the effects of incompatibility at present encountered to a greater or lesser extent with most combinations of alginate impression materials and gypsum cast materials. PMID:7018476

  17. 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

  18. 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+.

  19. 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.

  20. Magnetic field-responsive release of transforming growth factor beta 1 from heparin-modified alginate ferrogels.

    Science.gov (United States)

    Kim, Hwi; Park, Honghyun; Lee, Jae Won; Lee, Kuen Yong

    2016-10-20

    Stimuli-responsive polymeric systems have been widely used for various drug delivery and tissue engineering applications. Magnetic stimulation can be also exploited to regulate the release of pharmaceutical drugs, growth factors, and cells from hydrogels in a controlled manner, on-demand. In the present study, alginate ferrogels containing iron oxide nanoparticles were fabricated via ionic cross-linking, and their various characteristics were investigated. The deformation of the ferrogels was dependent on the polymer concentration, calcium concentration, iron oxide concentration, and strength of magnetic field. To modulate the release of transforming growth factor beta 1 (TGF-β1) under magnetic stimulation, alginate was chemically modified with heparin, as TGF-β1 has a heparin-binding domain. Alginate was first modified with ethylenediamine, and heparin was then conjugated to the ethylenediamine-modified alginate via carbodiimide chemistry. Conjugation of heparin to alginate was confirmed by infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. Sustained release of TGF-β1 from alginate-g-heparin ferrogels was achieved, and application of a magnetic field to the ferrogels regulated TGF-β1 release, resultantly enhancing chondrogenic differentiation of ATDC5 cells, which were used as a model chondrogenic cell line. Alginate-based ferrogels that release drugs in a controlled manner may therefore be useful in many biomedical applications. PMID:27474590

  1. 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.

  2. Carboxymethyl starch/alginate microspheres containing diamine oxidase for intestinal targeting

    Science.gov (United States)

    Blemur, Lindsay; Le, Tien Canh; Marcocci, Lucia; Pietrangeli, Paola

    2015-01-01

    Abstract The association of carboxymethyl starch (CMS) and alginate is proposed as a novel matrix for the entrapment of bioactive agents in microspheres affording their protection against gastrointestinal degradation. In this study, the enzyme diamine oxidase (DAO) from white pea (Lathyrus sativus) was immobilized by inclusion in microspheres formed by ionotropic gelation of CMS/alginate by complexation with Ca2+. The association of CMS to alginate generated a more compact structure presenting a lesser porosity, thus decreasing the access of gastric fluid inside the microspheres and preventing the loss of entrapped enzyme. Moreover, the immobilized enzyme remained active and was able to oxidize the polyamine substrates even in the presence of degrading proteases of pancreatin. The inclusion yield in terms of entrapped protein was of about 82%–95%. The DAO entrapped in calcium CMS/alginate beads retained up to 70% of its initial activity in simulated gastric fluid (pH 2.0). In simulated intestinal fluid (pH 7.2) with pancreatin, an overall retention of 65% of activity for the immobilized DAO was observed over 24 H, whereas in similar conditions the free enzyme was totally inactivated. Our project proposes the vegetal DAO as an antihistaminic agent orally administered to treat food histaminosis and colon inflammation. PMID:25779356

  3. 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

  4. 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

  5. Preparation and characterization of hydroxyapatite/sodium alginate biocomposites for bone implant application

    Science.gov (United States)

    Kanasan, Nanthini; Adzila, Sharifah; Suid, Mohd Syafiq; Gurubaran, P.

    2016-07-01

    In biomedical fields, synthetic scaffolds are being improved by using the ceramics, polymers and composites materials to avoid the limitations of allograft. Ceramic-polymer composites are appearing to be the most successful bone graft substitute in human body. The natural bones itself are well-known as composite of collagen and hydroxyapatite. In this research, precipitation method was used to synthesis hydroxyapatite (HA)/sodium alginate (SA) in various parameters. This paper describes the hydroxyapatite/sodium alginate biocomposite which suitable for use in bone defects or regeneration of bone through the characterizations which include FTIR, FESEM, EDS and DTA. In FTIR, the characteristi peaks of PO4-3 and OH- groups which corresponding to hydroxyapatite are existed in the mixing powders. The needle-size particle of hydroxyapatite/ alginate (HA/SA) are observed in FESEM in the range of 15.8nm-38.2nm.EDS confirmed the existence of HA/SA composition in the mixing powders. There is an endothermic peak which corresponds to the dehydration and the loss of physically adsorbed water molecules of the hydroxyapatite (HA)/sodium alginate (SA) powder which are described in DTA.

  6. Alginate fouling reduction of functionalized carbon nanotube blended cellulose acetate membrane in forward osmosis.

    Science.gov (United States)

    Choi, Hyeon-Gyu; Son, Moon; Yoon, SangHyeon; Celik, Evrim; Kang, Seoktae; Park, Hosik; Park, Chul Hwi; Choi, Heechul

    2015-10-01

    Functionalized multi-walled carbon nanotube blended cellulose acetate (fCNT-CA) membranes were synthesized for forward osmosis (FO) through phase inversion. The membranes were characterized through SEM, FTIR, and water contact angle measurement. AFM was utilized to investigate alginate fouling mechanism on the membrane. It reveals that the fCNT contributes to advance alginate fouling resistance in FO (57% less normalized water flux decline for 1% fCNT-CA membrane was observed than that for bare CA membrane), due to enhanced electrostatic repulsion between the membrane and the alginate foulant. Furthermore, it was found that the fCNT-CA membranes became more hydrophilic due to carboxylic groups in functionalized carbon nanotube, resulting in approximately 50% higher water-permeated flux than bare CA membrane. This study presents not only the fabrication of fCNT-CA membrane and its application to FO, but also the quantification of the beneficial role of fCNT with respect to alginate fouling in FO.

  7. 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

  8. in Situ Formation of a Biocatalytic Alginate Membrane by Enhanced Concentration Polarization

    DEFF Research Database (Denmark)

    Marpani, Fauziah; Luo, Jianquan; Mateiu, Ramona Valentina;

    2015-01-01

    immobilized enzyme loadings, which would benefit from the decreased flux in terms of increased enzyme/substrate contact time. The study was performed in a sequential fashion: first, the most suitable types of alginate able to induce a very thin, sustainable gel layer by pressure-driven membrane filtration...

  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.

  10. 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 ...

  11. 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.

  12. PCL/alginate composite scaffolds for hard tissue engineering: fabrication, characterization, and cellular activities.

    Science.gov (United States)

    Kim, Yong Bok; Kim, Geun Hyung

    2015-02-01

    Alginates have been used widely in biomedical applications because of good biocompatibility, low cost, and rapid gelation in the presence of calcium ions. However, poor mechanical properties and fabrication-ability for three-dimensional shapes have been obstacles in hard-tissue engineering applications. To overcome these shortcomings of alginates, we suggest a new composite system, consisting of a synthetic polymer, poly(ε-caprolactone), and various weight fractions (10-40 wt %) of alginate. The fabricated composite scaffolds displayed a multilayered 3D structure, consisting of microsized composite struts, and they provided a 100% offset for each layer. To show the feasibility of the scaffold for hard tissue regeneration, the composite scaffolds fabricated were assessed not only for physical properties, including surface roughness, tensile strength, and water absorption and wetting, but also in vitro osteoblastic cellular responses (cell-seeding efficiency, cell viability, fluorescence analyses, alkaline phosphatase (ALP) activity, and mineralization) by culturing with preosteoblasts (MC3T3-E1). Due to the alginate components in the composites, the scaffolds showed significantly enhanced wetting behavior, water-absorption (∼12-fold), and meaningful biological activities (∼2.1-fold for cell-seeding efficiency, ∼2.5-fold for cell-viability at 7 days, ∼3.4-fold for calcium deposition), compared with a pure PCL scaffold.

  13. 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

  14. 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

  15. 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

  16. 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

  17. Factors influencing the mechanical stability of alginate beads applicable for immunoisolation of mammalian cells

    NARCIS (Netherlands)

    Bhujbal, Swapnil V.; Paredes, Genaro A.; Niclou, Simone P.; de Vos, Paul

    2014-01-01

    Transplantation of microencapsulated cells has been proposed as a cure for many types of endocrine disorders. Alginate-based microcapsules have been used in many of the feasibility studied addressing cure of the endocrine disorders, and different cancer types. Despite years of intensive research it

  18. 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.

  19. 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.

  20. Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model

    DEFF Research Database (Denmark)

    Cao, Bao; Christophersen, Lars; Kolpen, Mette;

    2016-01-01

    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...

  1. Demonstrating Encapsulation and Release: A New Take on Alginate Complexation and the Nylon Rope Trick

    Science.gov (United States)

    Friedli, Andrienne C.; Schlager, Inge R.; Wright, Stephen W.

    2005-01-01

    Three variations on a classroom demonstration of the encapsulation of droplets and evidence for release of the interior solution are described. The first two demonstrations mimic biocompatible applications of encapsulation. Reversible formation of capsules from aqueous solutions of sodium alginate, a negatively charged polysaccharide derived from…

  2. Chemistry and the biological response against immunoisolating alginate-polycation capsules of different composition

    NARCIS (Netherlands)

    Ponce, Sara; Orive, Gorka; Hernandez, Rosa; Gascon, Alicia R.; Pedraz, Jose Luis; de Haan, Bart J.; Faas, Marijke M.; Mathieu, H. J.; de Vos, Paul

    2006-01-01

    Implantation of microencapsulated cells has been proposed as a therapy for a wide variety of diseases. An absolute requirement is that the applied microcapsules have an optimal biocompatibility. The alginate-poly-L-lysine system is the most commonly applied system but is still suffering from tissue

  3. Quantitative chemical mapping of sodium acrylate- and N-vinylpyrrolidone-enhanced alginate microcapsules.

    Science.gov (United States)

    Araki, Tohru; Hitchcock, Adam P; Shen, Feng; Chang, Patricia L; Wang, Maggie; Childs, Ronald F

    2005-01-01

    Alginate microcapsules enclosing recombinant cells secreting therapeutic products have been used successfully to treat several murine models of human diseases. The mechanical and chemical properties of these alginate capsules can be improved by the addition and in situ photo-polymerization of sodium acrylate and N-vinylpyrrolidone in the alginate capsule. The purpose of this modification was to form additional covalent cross-links. In this work we have used scanning transmission X-ray microscopy (STXM) to probe the nature and location of the chemical modifications in the modified capsules by comparison with unmodified capsules. Analysis of X-ray image sequences and selected area spectra has been used to map the calcium gradient in capsules, to identify the presence of polyacrylate throughout the capsules and the localization of poly-N-vinylpyrrolidone in the outer regions of the alginate capsules. The differences in the spatial distributions of these species have led to better understanding of the chemical modifications that provide a mechanically more stable capsule structure.

  4. Effects of Chitin Whiskers on Physical Properties and Osteoblast Culture of Alginate Based Nanocomposite Hydrogels.

    Science.gov (United States)

    Huang, Yao; Yao, Mengyu; Zheng, Xing; Liang, Xichao; Su, Xiaojuan; Zhang, Yu; Lu, Ang; Zhang, Lina

    2015-11-01

    Novel nanocomposite hydrogels composed of polyelectrolytes alginate and chitin whiskers with biocompatibility were successfully fabricated based on the pH-induced charge shifting behavior of chitin whiskers. The chitin whiskers with mean length and width of 300 and 20 nm were uniformly dispersed in negatively charged sodium alginate aqueous solution, leading to the formation of the homogeneous nanocomposite hydrogels. The experimental results indicated that their mechanical properties were significantly improved compared to alginate hydrogel and the swelling trends were inhibited as a result of the strong electrostatic interactions between the chitin whiskers and alginate. The nanocomposite hydrogels exhibited certain crystallinity and hierarchical structure with nanoscale chitin whiskers, similar to the structure of the native extracellular matrix. Moreover, the nanocomposite hydrogels were successfully applied as bone scaffolds for MC3T3-E1 osteoblast cells, showing their excellent biocompatibility and low cytotoxicity. The results of fluorescent micrographs and scanning electronic microscope (SEM) images revealed that the addition of chitin whiskers into the nanocomposite hydrogels markedly promoted the cell adhesion and proliferation of the osteoblast cells. The biocompatible nanocomposite hydrogels have potential application in bone tissue engineering.

  5. The alginate layer for improving doxorubicin release and radiolabeling stability of chitosan hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jeong Il; Lee, Chang Moon; Jeong, Hwan Seok; Hwang, Hyo Sook; Lim, Seok Tae; Sohn, Myung Hee; Jeong, Hwan Jeong [Dept. of Nuclear Medicine and Therapeutic Medicine Research Center, Cyclotron Research Center, Institute for Medical Science, Biomedical Research Institute, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Chang Moon [Dept. of Biomedical Engineering, Chonnam National University, Yeosu (Korea, Republic of)

    2015-12-15

    Chitosan hydrogels (CSH) formed through ionic interaction with an anionic molecule are suitable as a drug carrier and a tissue engineering scaffold. However, the initial burst release of drugs from the CSH due to rapid swelling after immersing in a biofluid limits their wide application as a drug delivery carrier. In this study, alginate layering on the surface of the doxorubicin (Dox)-loaded and I-131-labeled CSH (DI-CSH) was performed. The effect of the alginate layering on drug release behavior and radiolabeling stability was investigated. Chitosan was chemically modified using a chelator for I-131 labeling. After labeling of I-131 and mixing of Dox, the chitosan solution was dropped into tripolyphosphate (TPP) solution using an electrospinning system to prepare spherical microhydrogels. The DI-CSH were immersed into alginate solution for 30 min to form the crosslinking layer on their surface. The formation of alginate layer on the DI-CSH was confirmed by Fourier transform infrared spectroscopy (FT-IR) and zeta potential analysis. In order to investigate the effect of alginate layer, studies of in vitro Dox release from the hydrogels were performed in phosphate buffered in saline (PBS, pH 7.4) at 37 °C for 12 days. The radiolabeling stability of the hydrogels was evaluated using ITLC under different experimental condition (human serum, normal saline, and PBS) at 37 °C for 12 days. Formatting the alginate-crosslinked layer on the CSH surface did not change the spherical morphology and the mean diameter (150 ± 10 μm). FT-IR spectra and zeta potential values indicate that alginate layer was formed successfully on the surface of the DI-CSH. In in vitro Dox release studies, the total percentage of the released Dox from the DI-CSH for 12 days were 60.9 ± 0.8, 67.3 ± 1.4, and 71.8 ± 2.5 % for 0.25, 0.50, and 1.00 mg Dox used to load into the hydrogels, respectively. On the other hand, after formatting alginate layer, the percentage of the

  6. 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

  7. 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

  8. 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%)

  9. 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.

  10. 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)

  11. Calcium-Alginate-Inulin Microbeads as Carriers for Aqueous Carqueja Extract.

    Science.gov (United States)

    Balanč, Bojana; Kalušević, Ana; Drvenica, Ivana; Coelho, Maria Teresa; Djordjević, Verica; Alves, Vitor D; Sousa, Isabel; Moldão-Martins, Margarida; Rakić, Vesna; Nedović, Viktor; Bugarski, Branko

    2016-01-01

    Carqueja (Pterospartum tridentatum) is an endemic species and various bioactive compounds have been identified in its aqueous extract. The aim of this study was to protect the natural antioxidants from the aqueous extract of carqueja by encapsulation in Ca-alginate microbeads and Ca-alginate microbeads containing 10% and 20% (w/v) of inulin. The microbeads produced by electrostatic extrusion technique had an average diameter from 625 μm to 830 μm depending on the portion of inulin. The sphericity factor of the hydrogel microbeads had values between 0.014 and 0.026, while freeze dried microbeads had irregular shape, especially those with no excipient. The reduction in microbeads size after freeze drying process (expressed as shrinkage factor) ranged from 0.338 (alginate microbeads with 20% (w/v) of inulin) to 0.523 (plain alginate microbeads). The expressed radical scavenging activity against ABTS and DPPH radicals was found to be between 30% and 40% for encapsulated extract, while the fresh extract showed around 47% and 57% of radical scavenging activity for ABTS and DPPH radicals, respectively. The correlation between antioxidant activity and the total phenolic content were found to be positive (in both assay methods, DPPH and ABTS), which indicate that the addition of inulin didn't have influence on antioxidant activity. The presence of inulin reduced stiffness of the hydrogel, and protected bead structure from collapse upon freeze-drying. Alginate-inulin beads are envisaged to be used for delivery of aqueous P. tridentatum extract in functional food products.

  12. 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.

  13. 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.

  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. 超薄壁结构海藻酸钙胶囊膜制备及其功能化研究新进展%Recent progress in fabrication and functionalization of Ca-alginate capsules with ultrathin membranes

    Institute of Scientific and Technical Information of China (English)

    何帆; 谢锐; 巨晓洁; 汪伟; 刘壮; 褚良银

    2015-01-01

    could be controllably adjusted. The strategy reported in this paper provides a novel approach to fabricate novel structures of capsule membranes for various applications, particularly as a new tool for screening microorganism survival and growth in three-dimensional environments. Protamine is used to inspire andtemplate silica formation onto the surfaces of the Ca-alginate capsules, which provides a facile and efficient method to prepare the organic/inorganic hybrid capsules with ultrathin membranes. The Ca-alginate/ protamine/silica capsules efficiently inhibit the swelling of Ca-alginate capsules, and thus are promising carriers for encapsulation of cells and enzymes. In addition, Ca-alginate capsules membranes blended with poly(N-isopropylacrylamide) (PNIPAM) nanogels exhibit desirable thermo-responsive gating characteristics. pH-Responsive switching functions can be endowed by the electrostatic interactions between Ca-alginate networks and protamine molecules, or by the swelling/shrinking behaviors of the grafted poly(methacrylic acid) (PMAA) brushes on the capsule membranes. These functional capsules with ultrathin membranes have many potential applications in various fields such as enzyme catalytic reactions, immobilizations of cells and foods, and controlled release of chemicals.

  18. Impact of thermal annealing on wettability and antifouling characteristics of alginate poly-l-lysine polyelectrolyte multilayer films.

    Science.gov (United States)

    Diamanti, Eleftheria; Muzzio, Nicolas; Gregurec, Danijela; Irigoyen, Joseba; Pasquale, Miguel; Azzaroni, Omar; Brinkmann, Martin; Moya, Sergio Enrique

    2016-09-01

    Polyelectrolyte multilayers (PEMs) of poly-l-lysine (PLL) and alginic acid sodium salt (Alg) are fabricated applying the layer by layer technique and annealed at a constant temperature; 37, 50 and 80°C, for 72h. Atomic force microscopy reveals changes in the topography of the PEM, which is changing from a fibrillar to a smooth surface. Advancing contact angle in water varies from 36° before annealing to 93°, 77° and 95° after annealing at 37, 50 and 80°C, respectively. Surface energy changes after annealing were calculated from contact angle measurements performed with organic solvents. Quartz crystal microbalance with dissipation, contact angle and fluorescence spectroscopy measurements show a significant decrease in the adsorption of the bovine serum albumin protein to the PEMs after annealing. Changes in the physical properties of the PEMs are interpreted as a result of the reorganization of the polyelectrolytes in the PEMs from a layered structure into complexes where the interaction of polycations and polyanions is enhanced. This work proposes a simple method to endow bio-PEMs with antifouling characteristics and tune their wettability. PMID:27209385

  19. Synthesis of superparamagnetic carboxymethyl chitosan/sodium alginate nanosphere and its application for immobilizing α-amylase.

    Science.gov (United States)

    Jiang, Jianfang; Chen, Yongzheng; Wang, Wei; Cui, Baodong; Wan, Nanwei

    2016-10-20

    In order to improve catalytic activity, increase recycling times, reduce use cost for enzyme, superparamagnetic carboxymethyl chitosan/sodium alginate nanosphere (SM/CMC/SA) has been synthesized via an improved hydrothermal method, molecular self-assembly technology, electrostatic interaction and amide linkage. Its mean diameter was 65nm, zeta potential was -36.9mV and BET was 53.8m(2)/g. α-Amylase was selected as a simulation object to manufacture an immobilized enzyme (SM/CMC/CA/α-Amy), and its catalytic activity, release behavior, reusability and stability were researched. Immobilization increased 4.67 times to catalytic activity, slowed down release rate and improved reusable performance. SM/CMC/CA/α-Amy showed higher activity over a wider pH range, especially in strong acidic and alkaline environments. The thermal stability and storage stability were improved remarkably too. All these results indicated that SM/CMC/SA was an ideal carrier for immobilizing enzyme. PMID:27474605

  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. Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers

    OpenAIRE

    Lee, Bo Ram; Lee, Kwang Ho; Kang, Edward; Kim, Dong-Sik; LEE, Sang-Hoon

    2011-01-01

    The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fib...

  2. 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...

  3. 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...

  4. 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...

  5. Alginate controls heartburn in patients with erosive and nonerosive reflux disease

    Institute of Scientific and Technical Information of China (English)

    Edoardo Savarino; Nicola de Bortoli; Patrizia Zentilin; Irene Martinucci; Luca Bruzzone; Manuele Furnari; Santino Marchi

    2012-01-01

    AIM:To evaluate the effect of a novel alginate-based compound,Faringel,in modifying reflux characteristics and controlling symptoms.METHODS:In this prospective,open-label study,40 patients reporting heartburn and regurgitation with proven reflux disease (i.e.,positive impedance-pH test/evidence of erosive esophagitis at upper endoscopy) underwent 2 h impedance-pH testing after eating a refluxogenic meal.They were studied for 1 h under basal conditions and 1 h after taking 10 mL Faringel.In both sessions,measurements were obtained in right lateral and supine decubitus positions.Patients also completed a validated questionnaire consisting of a 2-item 5-point (0-4) Likert scale and a 10-cm visual analogue scale (VAS) in order to evaluate the efficacy of Faringel in symptom relief.Tolerability of the treatment was assessed using a 6-point Likert scale ranging from very good (1) to very poor (6).RESULTS:Faringel decreased significantly (P < 0.001),in both the right lateral and supine decubitus positions,esophageal acid exposure time [median 10 (25th-75th percentil 6-16) vs 5.8 (4-10) and 16 (11-19) vs 7.5 (5-11),respectively] and acid refluxes [5 (3-8) vs 1 (1-1) and 6 (4-8) vs 2 (1-2),respectively],but increased significantly (P < 0.01) the number of nonacid reflux events compared with baseline [2 (1-3) vs 3 (2-5) and 3 (2-4) vs 6 (3-8),respectively].Percentage of proximal migration decreased in both decubitus positions (60% vs 32% and 64% vs 35%,respectively; P < 0.001).Faringel was significantly effective in controlling heartburn,based on both the Likert scale [3.1(range 1-4) vs 0.9 (0-2); P < 0.001] and VAS score [7.1 (3-9.8) vs 2 (0.1-4.8); P < 0.001],but it had less success against regurgitation,based on both the Likert scale [2.6 (1-4) vs 2.2 (1-4); P =not significant (NS)]and VAS score [5.6 (2-9.6) vs 3.9 (1-8.8); P =NS].Overall,the tolerability of Faringel was very good 5(2-6),with only two patients reporting modest adverse events (i

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

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Y., E-mail: yuta-n@mech.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 096-8555 (Japan); Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611 (Japan); Tsusu, K.; Minami, K. [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611 (Japan); Nakanishi, Y. [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 096-8555 (Japan)

    2014-06-15

    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.

  7. 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)

  8. 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.

  9. Agarose- and alginate-based biopolymers for sample preparation: Excellent green extraction tools for this century.

    Science.gov (United States)

    Sanagi, Mohd Marsin; Loh, Saw Hong; Wan Ibrahim, Wan Nazihah; Pourmand, Neda; Salisu, Ahmed; Wan Ibrahim, Wan Aini; Ali, Imran

    2016-03-01

    Recently, there has been considerable interest in the use of miniaturized sample preparation techniques before the chromatographic monitoring of the analytes in unknown complex compositions. The use of biopolymer-based sorbents in solid-phase microextraction techniques has achieved a good reputation. A great variety of polysaccharides can be extracted from marine plants or microorganisms. Seaweeds are the major sources of polysaccharides such as alginate, agar, agarose, as well as carrageenans. Agarose and alginate (green biopolymers) have been manipulated for different microextraction approaches. The present review is focused on the classification of biopolymer and their applications in multidisciplinary research. Besides, efforts have been made to discuss the state-of-the-art of the new microextraction techniques that utilize commercial biopolymer interfaces such as agarose in liquid-phase microextraction and solid-phase microextraction.

  10. 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)

  11. Crosslinker effects on functional properties of alginate/N-succinylchitosan based hydrogels.

    Science.gov (United States)

    Straccia, Maria Cristina; Romano, Ida; Oliva, Adriana; Santagata, Gabriella; Laurienzo, Paola

    2014-08-01

    In this paper, physico-chemical, mechanical and antimicrobial properties of hydrogels based on alginate/N-succinylchitosan blends crosslinked by calcium or zinc ions containing cellulose microfibers were investigated and discussed. With respect to plain alginate hydrogels, the addition of N-succinylchitosan significantly improved properties such as swelling degree and stability in saline solution. The water vapour transmission rate confirmed that all the hydrogels were able to assure a moist wound environment. Morphological analysis showed a good embedding of fibres within the zinc crosslinked hydrogels. In addition, zinc-crosslinked hydrogels evidenced antimicrobial activity against two common skin pathogenic bacteria, Staphylococcus aureus and Escherichia coli. Cytotoxicity assays proved that the amount of zinc released is slightly over the toxic level. Overall, the characteristics of the zinc-crosslinked hydrogels showed their potential interest as materials for wound dressing.

  12. 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.

  13. 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.

  14. Tamoxifen-loaded thiolated alginate-albumin nanoparticles as antitumoral drug delivery systems.

    Science.gov (United States)

    Martínez, A; Benito-Miguel, M; Iglesias, I; Teijón, J M; Blanco, M D

    2012-06-01

    Nanoparticles based on disulfide bond reduced bovine serum albumin and thiolated alginate (alginate-cysteine conjugate) have been prepared by coacervation method and have been loaded with tamoxifen (TMX). The TMX load into the nanoparticles was optimized (4-6 μg/mg NP) by freeze-drying the systems before the loading procedure. Maximum TMX release (45-52%) took place between 2 and 25 h. Cytotoxicity of unloaded nanoparticles in MCF-7 and HeLa cells was not observed, although a small decrease in viability took place at very high concentration. Cell uptake of nanoparticles occurred in both cell types and the presence of polysaccharide in the nanoparticle composition allowed a better interaction with cells. The administration of 10 μM TMX by TMX-nanoparticles was effective in both cellular lines, and the effect of the drug-loaded systems on MCF-7 cell cycle showed the efficacy of the TMX-loaded nanoparticles. PMID:22396108

  15. 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

  16. 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.

  17. 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

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

    Directory of Open Access Journals (Sweden)

    Siti PM Bohari

    2012-12-01

    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.

  19. Optimization of a novel biocomposite synthesis (Ammi Visnaga extraction waste/alginate) for Cd(2+) biosorption.

    Science.gov (United States)

    Nouri, Loubna; Bendjama, Zoubida; Hamitouche, Adh'ya-eddine; Boumaza, Salim; Kaouah, Farida; Trari, Mohamed; Riad, Ladji

    2015-09-01

    A novel environmentally friendly biocomposite namely calcium alginate immobilized Ammi Visnaga (Khella) extraction waste was prepared by electrostatic extrusion method. A full factorial design 2(3) was used to optimize the beads preparation conditions. The effect of sodium alginate concentration (X1), biomass concentration (X2) and cross-linker concentration (X3) on the Cd(2+) removal efficiency was examined in a batch system with a fixed biocomposite dose of 1g/L. Using the experimental results, a linear mathematical model representing the influence of different variables and their interactions was obtained. The optimized values of X1, X2 and X3 were found to be 4.35%, 2.5% and 1.99% respectively. The biocomposite beads were characterized by ATR spectroscopy, scanning electron microscopy for the surface morphology and optical microscopic for the particles size measurements.

  20. 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.

  1. 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

  2. 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...

  3. 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...

  4. 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...

  5. 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.

  6. 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...

  7. 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.

  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. 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

  10. 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...

  11. 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.

  12. 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...

  13. Simultaneous Alcoholic and Malolactic Fermentations by Saccharomyces cerevisiae and Oenococcus oeni Cells Co-immobilized in Alginate Beads

    Science.gov (United States)

    Bleve, Gianluca; Tufariello, Maria; Vetrano, Cosimo; Mita, Giovanni; Grieco, Francesco

    2016-01-01

    Malolactic fermentation (MLF) usually takes place after the end of alcoholic fermentation (AF). However, the inoculation of lactic acid bacteria together with yeast starter cultures is a promising system to enhance the quality and safety of wine. In recent years, the use of immobilized cell systems has been investigated, with interesting results, for the production of different fermented foods and beverages. In this study we have carried out the simultaneous immobilization of Saccharomyces cerevisiae and Oenococcus oeni in alginate beads and used them in microvinifications tests to produce Negroamaro wine. The process was monitored by chemical and sensorial analyses and dominance of starters and cell leaking from beads were also checked. Co-immobilization of S. cerevisiae and O. oeni allowed to perform an efficient fermentation process, producing low volatile acidity levels and ethanol and glycerol concentrations comparable with those obtained by cell sequential inoculum and co-inoculum of yeast and bacteria cells in free form. More importantly, co-immobilization strategy produced a significant decrease of the time requested to complete AF and MLF. The immobilized cells could be efficiently reused for the wine fermentation at least three times without any apparent loss of cell metabolic activities. This integrated biocatalytic system is able to perform simultaneously AF and MLF, producing wines similar in organoleptic traits in comparison with wines fermented following traditional sequential AF and MLF with free cell starters. The immobilized-cell system, that we here describe for the first time in our knowledge, offers many advantages over conventional free cell fermentations, including: (i) elimination of non-productive cell growth phases; (ii) feasibility of continuous processing; (iii) re-use of the biocatalyst. PMID:27379072

  14. 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

  15. 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

  16. 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.

  17. Removal and recovery of uranium from aqueous solutions by Ca-alginate immobilized Trichoderma harzianum.

    Science.gov (United States)

    Akhtar, K; Khalid, A M; Akhtar, M W; Ghauri, M A

    2009-10-01

    The ability of Ca-alginate immobilized Trichoderma harzianum has been explored for removal and recovery of uranium from aqueous streams. Ca-alginate as polymeric support was selected after screening different matrices. Immobilization of Trichoderma harzianum to Ca-alginate improved the stability as well as uranium biosorption capacity of biosorbent at 28+/-2 degrees C and 200 rpm. The suitability of packed bed column operations was illustrated by obtaining break through curves at different bed heights, flow rates and inlet uranium concentrations. The adsorption column containing 1.5 g dry weight of immobilized material has purified 8.5L of bacterial leach liquor (58 mg/LU) before break through occurred and the biosorbent became saturated after 25 L of influent. Sorbed uranium was recovered in 200 ml of 0.1N HCl resulting in 98.1-99.3% elution by 0.1N HCl, which regenerated the biosorbent facilitating the sorption-desorption cycles for better economic feasibility without any significant alteration in sorption capacity/elution efficiency. PMID:19467596

  18. 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.

  19. 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

  20. 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

  1. A simple, quantitative method using alginate gel to determine rat colonic tumor volume in vivo.

    Science.gov (United States)

    Irving, Amy A; 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

    2014-04-01

    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 the shape of each original tumor. The weight of the dental stone cast correlates highly with the weight of the dissected tumors. After refinement of the technique, overall error in tumor volume was 16.9% ± 7.9% and includes error from both the alginate and dental stone procedures. Because this technique is limited to molding of tumors in the colon, we utilized the Apc(Pirc/+) rat, which has a propensity for developing colonic tumors that reflect the location of the majority of human intestinal tumors. We have successfully used the described method to determine tumor volumes ranging from 4 to 196 mm³. Alginate molding combined with dental stone casting is a facile method for determining tumor volume in vivo without costly equipment or knowledge of analytic software. This broadly accessible method creates the opportunity to objectively study colonic tumors over time in living animals in conjunction with other experiments and without transferring animals from the facility where they are maintained.

  2. 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

  3. Electrosprayed Multi-Core Alginate Microcapsules as Novel Self-Healing Containers

    Science.gov (United States)

    Hia, Iee Lee; Pasbakhsh, Pooria; Chan, Eng-Seng; Chai, Siang-Piao

    2016-01-01

    Alginate microcapsules containing epoxy resin were developed through electrospraying method and embedded into epoxy matrix to produce a capsule-based self-healing composite system. These formaldehyde free alginate/epoxy microcapsules were characterized via light microscope, field emission scanning electron microscope, fourier transform infrared spectroscopy and thermogravimetric analysis. Results showed that epoxy resin was successfully encapsulated within alginate matrix to form porous (multi-core) microcapsules with pore size ranged from 5–100 μm. The microcapsules had an average size of 320 ± 20 μm with decomposition temperature at 220 °C. The loading capacity of these capsules was estimated to be 79%. Under in situ healing test, impact specimens showed healing efficiency as high as 86% and the ability to heal up to 3 times due to the multi-core capsule structure and the high impact energy test that triggered the released of epoxy especially in the second and third healings. TDCB specimens showed one-time healing only with the highest healing efficiency of 76%. The single healing event was attributed by the constant crack propagation rate of TDCB fracture test. For the first time, a cost effective, environmentally benign and sustainable capsule-based self-healing system with multiple healing capabilities and high healing performance was developed. PMID:27694922

  4. 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.

  5. A comprehensive approach to in vitro functional evaluation of Ag/alginate nanocomposite hydrogels.

    Science.gov (United States)

    Stojkovska, Jasmina; Kostić, Danijela; Jovanović, Željka; Vukašinović-Sekulić, Maja; Mišković-Stanković, Vesna; Obradović, Bojana

    2014-10-13

    In this work, we present a comprehensive approach to evaluation of alginate microbeads with included silver nanoparticles (AgNPs) at the concentration range of 0.3-5mM for potential biomedical use by combining cytotoxicity, antibacterial activity, and silver release studies. The microbeads were investigated regarding drying and rehydration showing retention of ∼ 80-85% of the initial nanoparticles as determined by UV-vis and SEM analyses. Both wet and dry microbeads were shown to release AgNPs and/or ions inducing similar growth delays of Staphylococcus aureus and Escherichia coli at the total released silver concentrations of ∼ 10 μg/ml. On the other hand, these concentrations were highly toxic for bovine chondrocytes in conventional monolayer cultures while nontoxic when cultured in alginate microbeads under biomimetic conditions in 3D perfusion bioreactors. The applied approach outlined directions for further optimization studies demonstrating Ag/alginate microbeads as potentially attractive components of soft tissue implants as well as antimicrobial wound dressings.

  6. Microencapsulation of Lactobacillus plantarum spp in an alginate matrix coated with whey proteins.

    Science.gov (United States)

    Gbassi, Gildas Komenan; Vandamme, Thierry; Ennahar, Saïd; Marchioni, Eric

    2009-01-31

    Whey proteins were used as a coating material to improve encapsulation of Lactobacillus plantarum strains in calcium alginate beads. L. plantarum 299v, L. plantarum 800 and L. plantarum CIP A159 were used in this study. Inactivation experiments were carried out in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Cross-sections of freeze-dried beads revealed the random distribution of bacteria throughout the alginate network. From an initial count of 10.04+/-0.01 log(10) CFU g(-1) for L. plantarum 299v, 10.12+/-0.04 for L. plantarum CIP A159 and 10.03+/-0.01 for L. plantarum 800, bacteria in coated beads and incubated in SGF (37 degrees C, 60 min) showed a better survival for L. plantarum 299v, L. plantarum CIP A159 and L. plantarum 800 (respectively 7.76+/-0.12, 6.67+/-0.08 and 5.81+/-0.25 log(10) CFU g(-1)) when compared to uncoated beads (2.19+/-0.09, 1.89+/-0.09 and 1.65+/-0.10 log(10) CFU g(-1)) (p<0.05). Only bacteria in the coated beads survived in the SIF medium (37 degrees C, 180 min) after SGF treatment. This preliminary work showed that whey proteins are a convenient, cheap and efficient material for coating alginate beads loaded with bacteria.

  7. Effects of mixing technique on bubble formation in alginate impression material.

    Science.gov (United States)

    McDaniel, Thomas F; Kramer, Robert T; Im, Francis; Snow, Dallin

    2013-01-01

    Previous studies have found that variations in mixing technique can influence the porosity content of alginate impression material. The aim of this study was twofold: determine whether bubble formation in alginate is influenced by the sequence of water/powder addition prior to mixing, and to compare 4 different mixing techniques. Manual spatulation, an automated spinning bowl, a centrifugal mixer and a vacuum mixer were evaluated for the resulting porosity in the set alginate. It was found that adding powder first, versus water first, made no difference in the bubble content using the 3 automated mixing techniques (P = 0.714). However, porosity was significantly less for powder-first trials using manual spatulation (P < 0.05). It was also found that surface porosity in the resulting impressions was significantly less for centrifugal and vacuum mixing when compared to manual spatulation, while internal porosity was significantly less for centrifugal mixing compared to all other mixing techniques (P < 0.05). The centrifugal mixing and vacuum mixing techniques required the least amount of mixing time. PMID:24064161

  8. 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

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

    Science.gov (United States)

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

    2011-07-01

    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 60Co 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 -1, improved the growth attributes, photosynthetic capability, enzyme activities and artemisinin content of the plant significantly. Application of ISA at 80 mg L -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 2O 2 content in the leaves.

  10. 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.

  11. Streptomycin-loaded PLGA-alginate nanoparticles: preparation, characterization, and assessment

    Science.gov (United States)

    Asadi, Asadollah

    2014-04-01

    The aim of this study was to formulate and characterize streptomycin-loaded PLGA-alginate nanoparticles for their potential therapeutic use in Salmonella subsp. enterica ATCC 14028 infections. The streptomycin nanoparticle was prepared by solvent diffusion method, and the other properties such as size, zeta potential, loading efficacy, release kinetics, and antimicrobial strength were evaluated. The survey shows that nanoparticles may serve as a carrier of streptomycin and may provide localized antibacterial activity in the treatment of Salmonellosis. Electron microscopy showed spherical particles with indentations. The average size of the nanoparticles was 90 nm. At pH 7.2, the release kinetics of streptomycin from the nanoparticles was successfully illustrated as an initial burst defined by a first order equation that after this stage, it has a drastic tendency to obtain steady state. Nevertheless, nanoparticles showed loading efficacy nearly about 70-75 %. In addition, the tendency of concentration of streptomycin released from nanoparticles to reach antibacterial activity was similar to that of free streptomycin against PLGA-alginate, but it had threefold more antimicrobial strength in comparison with free streptomycin. This work shows the potential use of streptomycin-loaded PLGA-alginate nanoparticles and its capability.

  12. Three-dimensional electrospun alginate nanofiber mats via tailored charge repulsions.

    Science.gov (United States)

    Bonino, Christopher A; Efimenko, Kirill; Jeong, Sung In; Krebs, Melissa D; Alsberg, Eben; Khan, Saad A

    2012-06-25

    The formation of 3D electrospun mat structures from alginate-polyethylene oxide (PEO) solution blends is reported. These unique architectures expand the capabilities of traditional electrospun mats for applications such as regenerative medicine, where a scaffold can help to promote tissue growth in three dimensions. The mat structures extend off the surface of the flat collector plate without the need of any modifications in the electrospinning apparatus, are self-supported when the electric field is removed, and are composed of bundles of nanofibers. A mechanism for the unique formations is proposed, based on the fiber-fiber repulsions from surface charges on the negatively charged alginate. Furthermore, the role of the electric field in the distribution of alginate within the nanofibers is discussed. X-ray photoelectron spectroscopy is used to analyze the surface composition of the electrospun nanofiber mats and the data is related to cast films made in the absence of the electric field. Further techniques to tailor the 3D architecture and nanofiber morphology by changing the surface tension and relative humidity are also discussed.

  13. Effect of Diffusion on Discoloration of Congo Red by Alginate Entrapped Turnip (Brassica rapa Peroxidase

    Directory of Open Access Journals (Sweden)

    Afaf Ahmedi

    2015-01-01

    Full Text Available 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 (De 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.

  14. Electrosprayed Multi-Core Alginate Microcapsules as Novel Self-Healing Containers

    Science.gov (United States)

    Hia, Iee Lee; Pasbakhsh, Pooria; Chan, Eng-Seng; Chai, Siang-Piao

    2016-10-01

    Alginate microcapsules containing epoxy resin were developed through electrospraying method and embedded into epoxy matrix to produce a capsule-based self-healing composite system. These formaldehyde free alginate/epoxy microcapsules were characterized via light microscope, field emission scanning electron microscope, fourier transform infrared spectroscopy and thermogravimetric analysis. Results showed that epoxy resin was successfully encapsulated within alginate matrix to form porous (multi-core) microcapsules with pore size ranged from 5–100 μm. The microcapsules had an average size of 320 ± 20 μm with decomposition temperature at 220 °C. The loading capacity of these capsules was estimated to be 79%. Under in situ healing test, impact specimens showed healing efficiency as high as 86% and the ability to heal up to 3 times due to the multi-core capsule structure and the high impact energy test that triggered the released of epoxy especially in the second and third healings. TDCB specimens showed one-time healing only with the highest healing efficiency of 76%. The single healing event was attributed by the constant crack propagation rate of TDCB fracture test. For the first time, a cost effective, environmentally benign and sustainable capsule-based self-healing system with multiple healing capabilities and high healing performance was developed.

  15. Alginate/chitosan nanoparticles for encapsulation and controlled release of vitamin B2.

    Science.gov (United States)

    Azevedo, Maria A; Bourbon, Ana I; Vicente, António A; Cerqueira, Miguel A

    2014-11-01

    This work aims at evaluating encapsulation and controlled release of vitamin B2 from alginate/chitosan nanoparticles. Ionotropic polyelectrolyte pre-gelation was used as production method being chitosan and alginate used as main materials. Nanoparticles were characterized in terms of average size, polydispersity index (PDI), zeta potential and vitamin entrapment efficiency. The average size for alginate/chitosan nanoparticles was 119.5±49.9nm for samples without vitamin B2 and 104.0±67.2nm with the encapsulation of vitamin B2, presenting a PDI of 0.454±0.066 and 0.319±0.068, respectively. The nanoparticles showed encapsulation efficiency and loading capacity values of 55.9±5.6% and 2.2±0.6%, respectively. Release profiles were evaluated at different conditions showing that the polymeric relaxation was the most influent phenomenon in vitamin B2 release. In order to study their stability nanoparticles were stored at 4°C being particles sizes and PDI evaluated during 5 months showing the results that vitamin B2-loaded nanoparticles are more stable (in terms of size and PDI) than nanoparticles without vitamin B2.

  16. General Approach to the Immobilization of Glycoenzyme Chains Inside Calcium Alginate Beads for Bioassay.

    Science.gov (United States)

    Mallardi, Antonia; Angarano, Valeria; Magliulo, Maria; Torsi, Luisa; Palazzo, Gerardo

    2015-11-17

    A general method to obtain the efficient entrapment of mixtures of glycoenzymes in calcium alginate hydrogel is proposed in this paper. As a proof of principle, three glycoenzymes acting in series (trehalase, glucose oxidase, and horseradish peroxidase) have been coimmobilized in calcium alginate beads. The release of the enzymes from the hydrogel mesh (leakage) is avoided by exploiting the enzyme's aggregation induced by the concanavalin A. The aggregation process has been monitored by dynamic light scattering technique, while both enzyme encapsulation efficiency and leakage have been quantified spectrophotometrically. Obtained data show an encapsulation efficiency above 95% and a negligible leakage from the beads when enzyme aggregates are larger than 300 nm. Operational stability of "as prepared" beads has been largely improved by a coating of alternated shells of polycation poly(diallyldimethylammonium chloride) and of alginate. As a test for the effectiveness of the overall procedure, analytical bioassays exploiting the enzyme-containing beads have been developed for the optical determination of glucose and trehalose, and limit of detection values of 0.2 and of 40 μM, respectively, have been obtained.

  17. Novel Alginate-Gelatin Hybrid Nanoparticle for Drug Delivery and Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Eun Mi Lee

    2014-01-01

    Full Text Available Novel alginate-gelatin hybrid nanoparticles were fabricated using single oil in water (O/W emulsification techniques. Physicochemical property of the particle was characterized using scanning electron microscopy and Fourier’s transmission infrared spectroscopy. Particle size was determined using zeta potential metastasize analyzer and was found to be in range of 400–600 nm. AGNPs were used for culturing human keratinocytes for two weeks to check biocompatibility of synthesized AGNPs. 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay showed increased metabolic activity of cells cultured on AGNPs in comparison to two-dimensional (2D system (control. Cellular attachment on nanoparticle was further confirmed using SEM and 4′,6-diamidino-2-phenylindole staining. The drug release profile shows possible electrostatic bond between alginate and gelatin resulting in controlled release of drug from AGNPs. For the first time alginate-gelatin hybrid nanosystem has been fabricated and all results showed it can be used as potential system for delivery of drug and therapeutical agents to cells and can also be used for regenerative medicine applications.

  18. Ultrasoft Alginate Hydrogels Support Long-Term Three-Dimensional Functional Neuronal Networks.

    Science.gov (United States)

    Palazzolo, Gemma; Broguiere, Nicolas; Cenciarelli, Orlando; Dermutz, Harald; Zenobi-Wong, Marcy

    2015-08-01

    Neuron development and function are exquisitely sensitive to the mechanical properties of their surroundings. Three-dimensional (3D) cultures are therefore being explored as they better mimic the features of the native extracellular matrix. Limitations of existing 3D culture models include poorly defined composition, rapid degradation, and suboptimal biocompatibility. Here we show that ionically cross-linked ultrasoft hydrogels made from unmodified alginate can potently promote neuritogenesis. Alginate hydrogels were characterized mechanically and a remarkable range of stiffness (10-4000 Pa) could be produced by varying the macromer content (0.1-0.4% w/v) and CaCl2 concentration. Dissociated rat embryonic cortical neurons encapsulated within the softest of the hydrogels (0.1% w/v, 10 mM CaCl2) showed excellent viability, extensive formation of axons and dendrites, and long-term activity as determined by calcium imaging. In conclusion, alginate is an off-the-shelf, easy to handle, and inexpensive material, which can be used to make ultrasoft hydrogels for the formation of stable and functional 3D neuronal networks. This 3D culture system could have important applications in neuropharmacology, toxicology, and regenerative medicine.

  19. Oral delivery of probiotic expressing M cell homing peptide conjugated BmpB vaccine encapsulated into alginate/chitosan/alginate microcapsules.

    Science.gov (United States)

    Jiang, Tao; Singh, Bijay; Maharjan, Sushila; Li, Hui-Shan; Kang, Sang-Kee; Bok, Jin-Duck; Cho, Chong-Su; Choi, Yun-Jaie

    2014-11-01

    Oral administration of live probiotics as antigen delivery vectors is a promising approach in vaccine development. However, the low survival of probiotics in the gastrointestinal tract limits this approach. Therefore, the aim of this study was the encapsulation of probiotic expressing vaccine into alginate/chitosan/alginate (ACA) microcapsules (MCs) for efficient oral vaccine delivery. Here, recombinant Lactobacillus plantarum 25 (LP25) expressing M cell homing peptide fused BmpB protein was used as a model probiotic. The viability of LP25 in ACA MCs was more than 65% in simulated gastric fluid (SGF, pH 2.0) and 75% in simulated small intestinal fluid (SIF, pH 7.2) up to 2h. Encapsulated LP25 was completely released from ACA MCs in SIF within 12h. When stored at room temperature (RT) or 4°C, the viability of LP25 in ACA MCs was higher than free LP25. Interestingly, the viability of LP25 in ACA MCs at 4°C for 5weeks was above 58%, whereas viability of free LP25 stored at RT up to 5weeks was zero. After 4weeks from the first immunization, LP25-M-BmpB-loaded ACA MCs induced a stronger BmpB-specific IgG and IgA production in mice. Collectively, these findings suggest that encapsulation of probiotic by ACA MCs is a promising delivery system for oral administration of probiotic expressing vaccine.

  20. Novel tamarind seed polysaccharide-alginate mucoadhesive microspheres for oral gliclazide delivery: in vitro-in vivo evaluation.

    Science.gov (United States)

    Pal, Dilipkumar; Nayak, Amit Kumar

    2012-04-01

    Novel tamarind seed polysaccharide (TSP)-alginate mucoadhesive microspheres were prepared using TSP and alginate as blend in different ratios with different calcium chloride (CaCl(2)) concentration as a cross linker by ionotropic gelation. The prepared microspheres were of spherical shape having rough surfaces, and average particle sizes within the range of 752.12 ± 6.42 to 948.49 ± 20.92 µm. The drug entrapment efficiency of these microspheres were within the range between 58.12 ± 2.42 to 82.78 ± 3.43% w/w. Fourier transform infrared (FTIR) studies indicated that there were no reactions between gliclazide, and polymers (TSP, and sodium alginate) used. Different formulations of gliclazide loaded TSP-alginate microspheres showed prolonged in vitro release profiles of gliclazide over 12 hours in both stomach pH (pH 1.2), and intestinal pH (pH 7.4). It was found that the gliclazide release in gastric pH was comparatively slow and sustained than intestinal pH. These TSP-alginate microspheres also exhibited good mucoadhesivity. The in vivo studies on alloxan-induced diabetic rats (Animal Ethical Committee registration number: IFTM/837ac/0160) demonstrated the significant hypoglycemic effect of selected formulation of TSP-alginate mucoadhesive microspheres containing gliclazide on oral administration. This developed gliclazide loaded new TSP-alginate mucoadhesive microspheres may be very much useful for prolonged systemic absorption of gliclazide for proper maintaining blood glucose level and advanced patient compliance.