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Sample records for psk2 restored alginate

  1. Characterization and restoration of degenerated IVD function with an injectable, in situ gelling alginate hydrogel: An in vitro and ex vivo study.

    Science.gov (United States)

    Growney Kalaf, Emily A; Pendyala, Meghana; Bledsoe, J Gary; Sell, Scott A

    2017-08-01

    Intervertebral disc (IVD) degeneration is a naturally, irreparable process that causes loss in IVD hydration, cellularity, and, mechanical stability. Invasive surgical attempts to ease back pain and, radiculopathy have shown to cause increased degeneration along the rest, of the spine. Due to its highly tunable mechanical and degradation, properties, alginate is a viable option for a less-invasive injectable, repair for IVD degeneration. This study centers on the characterization, of in situ gelling alginate and subsequent injection into enzymatically, degraded motion segments., In situ gelation of 2% alginate (% w/v PBS) was performed using calcium, carbonate (CaCO3) and glucono-δ-lactone (GDL) and compared to, instantaneously gelled 2% alginate crosslinked with calcium chloride., After characterization of multiple molar concentrations, a ratio of, 60mM:120mM CaCO3:GDL was determined to have the most optimum properties, for injection. Enzymatically degraded bovine caudal motion segments were, injected with the optimized in situ gelling alginate and mechanically, loaded; injected motion segments were compared to intact specimens, degraded specimens, and specimens injected with 20% gelatin to, corroborate with previous ex vivo injection studies., Overall, injection of in situ curing 2% alginate into an enzymatically, and mechanically degraded IVD restores function via reduction of height, loss over long-term cyclic loading, is constrained within the disc with, no injection site leakage, and successfully fills all void spaces created, by chemonucleolysis with 1% collagenase-f. These findings, along with the, ability of alginate to be specifically tailored to support cell, viability, show promise for a tissue engineered injectable NP substitute for the reversal of disc degeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Alginate oligosaccharides

    DEFF Research Database (Denmark)

    Falkeborg, Mia; Cheong, Ling-Zhi; Gianfico, Carlo

    2014-01-01

    the presence of the conjugated alkene acid structure formed during enzymatic depolymerization. According to the resonance hybrid theory, the parent radicals of AOs are delocalized through allylic rearrangement, and as a consequence, the reactive intermediates are stabilized. AOs were weak ferrous ion chelators....... This work demonstrated that AOs obtained from a facile enzymatic treatment of abundant alginate is an excellent natural antioxidant, which may find applications in the food industry....

  3. Coating of alginate capsules

    OpenAIRE

    Hadjialirezaei, Soosan

    2013-01-01

    Alginate is a popular candidate for encapsulation of cells due to the formation of gels with divalent ions under physiological conditions. Stable alginate gels can be formed by the selection of alginates with a high content of guluronic acid (G) and gelling in a mixture of calcium and barium. These alginate gels have been proposed as immune protective barriers for the transplantation of human pancreatic islets (insulin producing cells) for the treatment of type 1 diabetes where the alginate g...

  4. Impact of alginate-producing Pseudomonas aeruginosa on alveolar macrophage apoptotic cell clearance

    Science.gov (United States)

    Poirier, Christophe; Serban, Karina A.

    2014-01-01

    Pseudomonas aeruginosa infection is a hallmark of lung disease in cystic fibrosis. Acute infection with P. aeruginosa profoundly inhibits alveolar macrophage clearance of apoptotic cells (efferocytosis) via direct effect of virulence factors. During chronic infection, P. aeruginosa evades host defense by decreased virulence, which includes the production or, in the case of mucoidy, overproduction of alginate. The impact of alginate on innate immunity, in particular on macrophage clearance of apoptotic cells is not known. We hypothesized that P. aeruginosa strains that exhibit reduced virulence impair macrophage clearance of apoptotic cells and we investigated if the polysaccharide alginate produced by mucoid P. aeruginosa is sufficient to inhibit alveolar macrophage efferocytosis. Rat alveolar or human peripheral blood monocyte (THP-1)-derived macrophages cell lines were exposed in vitro to exogenous alginate or to wild type or alginate-overproducing mucoid P. aeruginosa prior to challenge with apoptotic human Jurkat T-lymphocytes. The importance of LPS contamination and that of structural integrity of alginate polymers was tested using alginate of different purities and alginate lyase, respectively. Alginate inhibited alveolar macrophage efferocytosis in a dose- and time-dependent manner. This effect was augmented but not exclusively attributed to lipopolysaccharide (LPS) present in alginates. Alginate-producing P. aeruginosa inhibited macrophage efferocytosis by more than 50%. Although alginate lyase did not significantly restore efferocytosis in the presence of exogenous alginate, it had a marked beneficial effect on efferocytosis of alveolar macrophages exposed to mucoid P. aeruginosa. Despite decreased virulence, mucoid P. aeruginosa may contribute to ongoing airway inflammation through significant inhibition of alveolar clearance of apoptotic cells and debris. The mechanism by which mucoid bacteria inhibit efferocytosis may involve alginate production and

  5. 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

  6. 21 CFR 184.1187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005.... Calcium alginate is prepared by the neutralization of purified alginic acid with appropriate pH control...

  7. 21 CFR 184.1610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No... algae. Potassium alginate is prepared by the neutralization of purified alginic acid with appropriate pH...

  8. Oxidized alginate hydrogels for BMP-2 delivery in long bone defects

    Science.gov (United States)

    Priddy, Lauren B; Chaudhuri, Ovijit; Stevens, Hazel Y; Krishnan, Laxminarayanan; Uhrig, Brent A; Willett, Nick J; Guldberg, Robert E

    2014-01-01

    Autograft treatment of large bone defects and fracture non-unions is complicated by limited tissue availability and donor site morbidity. Polymeric biomaterials such as alginate hydrogels provide an attractive tissue engineering alternative due to their biocompatibility, injectability, and tunable degradation rates. Irradiated RGD-alginate hydrogels have been used to deliver proteins such as bone morphogenetic protein-2 (BMP-2), to promote bone regeneration and restoration of function in a critically sized rat femoral defect model. However, slow degradation of irradiated alginate hydrogels may impede integration and remodeling of the regenerated bone to its native architecture. Oxidation of alginate has been used to promote degradation of alginate matrices. The objective of this study was to evaluate the effects of alginate oxidation on BMP-2 release and bone regeneration. We hypothesized that oxidized-irradiated alginate hydrogels would elicit an accelerated release of BMP-2, but degrade faster in vivo, facilitating the formation of higher quality, more mature bone compared to irradiated alginate. Indeed, oxidation of irradiated alginate did accelerate in vitro BMP-2 release. Notably, the BMP-2 retained within both constructs was bioactive at 26 days, as observed by induction of alkaline phosphatase activity and positive Alizarin Red S staining of MC3T3-E1 cells. From the in vivo study, robust bone regeneration was observed in both groups through 12 weeks by radiography, micro-CT analyses, and biomechanical testing. Bone mineral density (BMD) was significantly greater for the oxidized-irradiated alginate group at 8 weeks. Histological analyses of bone defects revealed enhanced degradation of oxidized-irradiated alginate and suggested the presence of more mature bone after 12 weeks of healing. PMID:24954001

  9. Microbial alginate production, modification and its applications

    Science.gov (United States)

    Hay, Iain D; Rehman, Zahid Ur; Moradali, M Fata; Wang, Yajie; Rehm, Bernd H A

    2013-01-01

    Alginate is an important polysaccharide used widely in the food, textile, printing and pharmaceutical industries for its viscosifying, and gelling properties. All commercially produced alginates are isolated from farmed brown seaweeds. These algal alginates suffer from heterogeneity in composition and material properties. Here, we will discuss alginates produced by bacteria; the molecular mechanisms involved in their biosynthesis; and the potential to utilize these bacterially produced or modified alginates for high-value applications where defined material properties are required. PMID:24034361

  10. Imunomodulator Activity of Alginate Oligosaccharides from Alginate Sargassum crassifolium

    Directory of Open Access Journals (Sweden)

    Subaryono Subaryono

    2017-04-01

    Full Text Available Alginate oligosaccharides (AOS are oligosaccharides produced from depolimerization of the alginate polymer, and is reported to have various biological activities. The study aims is to determine the effect of AOSproduction conditions and their effects on products and its activities as an immunomodulatory compound. Production of alginate oligosaccharides (AOS enzymatically carried out with the help of alginate lyase enzyme produced from the bacterium Bacillus megaterium S245. Variation of incubation time is 2, 4, 6 and 8 hours at concentrations of alginate lyase enzyme addition of 25, 50, 75 and 100U. Treatment of enzyme concentration and the duration of incubation in the production of AOS produces a degree of polymerization (DP 2-7. In vitro activity test showed AOS is have ability to induce cell proliferation of human lymphocytes.This type of cell lymphocytes proliferation induced by AOS is a CD 8 cells or cytotoxic T cell and non cell CD4 / CD8. AOS production conditions with the addition of alginate lyase enzyme 50 U and incubation period 2 hours has produce AOS with the highest index of lymphocyte proliferation  117.6+3.6% or an increase of 43.24% compared to the native alginat polymer.

  11. 21 CFR 582.7724 - Sodium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized as...

  12. 21 CFR 582.7133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium alginate. 582.7133 Section 582.7133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Ammonium alginate. (a) Product. Ammonium alginate. (b) Conditions of use. This substance is generally...

  13. 21 CFR 582.7187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

  14. 21 CFR 582.7610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is generally...

  15. 21 CFR 184.1011 - Alginic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Alginic acid. 184.1011 Section 184.1011 Food and... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal, hydrophilic.../code_of_federal_regulations/ibr_locations.html. (c) In accordance with § 184.1(b)(2), the ingredient is...

  16. 21 CFR 184.1133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food... Specific Substances Affirmed as GRAS § 184.1133 Ammonium alginate. (a) Ammonium alginate (CAS Reg. No. 9005... accordance with § 184.1(b)(2), the ingredient is used in food only within the following specific limitations...

  17. Efficient functionalization of alginate biomaterials.

    Science.gov (United States)

    Dalheim, Marianne Ø; Vanacker, Julie; Najmi, Maryam A; Aachmann, Finn L; Strand, Berit L; Christensen, Bjørn E

    2016-02-01

    Peptide coupled alginates obtained by chemical functionalization of alginates are commonly used as scaffold materials for cells in regenerative medicine and tissue engineering. We here present an alternative to the commonly used carbodiimide chemistry, using partial periodate oxidation followed by reductive amination. High and precise degrees of substitution were obtained with high reproducibility, and without formation of by-products. A protocol was established using l-Tyrosine methyl ester as a model compound and the non-toxic pic-BH3 as the reducing agent. DOSY was used to indirectly verify covalent binding and the structure of the product was further elucidated using NMR spectroscopy. The coupling efficiency was to some extent dependent on alginate composition, being most efficient on mannuronan. Three different bioactive peptide sequences (GRGDYP, GRGDSP and KHIFSDDSSE) were coupled to 8% periodate oxidized alginate resulting in degrees of substitution between 3.9 and 6.9%. Cell adhesion studies of mouse myoblasts (C2C12) and human dental stem cells (RP89) to gels containing various amounts of GRGDSP coupled alginate demonstrated the bioactivity of the material where RP89 cells needed higher peptide concentrations to adhere. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. 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. Copyright © 2013 John Wiley & Sons, Ltd.

  19. 3D Cell Culture in Alginate Hydrogels.

    Science.gov (United States)

    Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael

    2015-03-24

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

  20. Perfluorinated alginate for cellular encapsulation.

    Science.gov (United States)

    Gattás-Asfura, Kerim M; Fraker, Christopher A; Stabler, Cherie L

    2012-08-01

    Molecules of pentadecafluorooctanoyl chloride (PFC) were grafted onto alginate (Alg) using a linear poly(ethylene glycol) linker and amide bonds. The resulting Alg-PFC material was characterized by proton nuclear magnetic resonance and infrared spectroscopies. The degree of PFC functionalization significantly influenced the physical and chemical properties of Alg-PFC, particularly when the resulting polymer was ionically crosslinked into hydrogels. Alg-PFC hydrogel beads fabricated via Ba(2+) crosslinking were found to match the permeability properties of control alginate beads, except upon swelling over time in culture media. When used to encapsulate MIN6 cells, a beta cell line, Alg-PFC beads demonstrated enhanced cell proliferation over alginate control beads. These results indicate that Alg-PFC hydrogels retain some of the PFC's biological-relevant benefits, such as enhancement of mass transport and bioinertness, to enhance cellular viability within alginate three-dimensional hydrogel environments. We envision these functionalized hydrogels to be particularly useful in the encapsulation of cells with a high metabolic demand, such as pancreatic islets. Copyright © 2012 Wiley Periodicals, Inc.

  1. Thermostable Alginate degrading enzymes and their methods of use

    NARCIS (Netherlands)

    Hreggvidsson, Gudmundur Oli; Jonsson, Oskar W.J.; Bjornsdottir, Bryndis; Fridjonsson, Hedinn O; Altenbuchner, Josef; Watzlawick, Hildegard; Dobruchowska, Justyna; Kamerling, Johannis

    2015-01-01

    The present invention relates to the identification, production and use of thermostable alginate lyase enzymes that can be used to partially degrade alginate to yield oligosaccharides or to give complete degradation of alginate to yield (unsaturated) mono-uronates.

  2. Rheological characterization of an injectable alginate gel system

    OpenAIRE

    Larsen, Benjamin E; Bjørnstad, Jorunn; Pettersen, Erik O; Tønnesen, Hanne H; Melvik, Jan E

    2015-01-01

    Background This work investigates a general method for producing alginate gel matrices using an internal mode of gelation that depends solely on soluble alginate and alginate/gelling ion particles. The method involves the formulation of two-component kits comprised of soluble alginate and insoluble alginate/gelling ion particles. Gelling kinetics, elastic and Young’s moduli were investigated for selected parameters with regard to soluble alginate guluronate content, molecul...

  3. Alginate Microbeads for Cell and Protein Delivery.

    Science.gov (United States)

    Somo, Sami I; Khanna, Omaditya; Brey, Eric M

    2017-01-01

    Alginate hydrogels have been used for a broad variety of medical applications. The ability to assemble alginate gels at neutral pH and mild temperatures makes alginate a promising choice for the encapsulation and delivery of cells and proteins. This chapter covers the basics of cell encapsulation and protein delivery using two different variations of alginate microbeads, single layered and multilayer systems. The first section describes a method for encapsulating cells within alginate microbeads coated with a permselective polymer layer. The second section describes a multilayer alginate microbead system that allows simultaneous encapsulation of cells and delivery of growth factors. The primary goal of the systems described is for encapsulation of islets as a treatment for type I diabetes. However, these microbeads can be used for a broad variety of applications in tissue engineering, cell encapsulation, and regenerative medicine.

  4. Anaerobic production of alginate by Pseudomonas aeruginosa: alginate restricts diffusion of oxygen.

    OpenAIRE

    Hassett, D J

    1996-01-01

    Pseudomonas aeruginosa produced alginate and elevated algD (encoding GDPmannose 6-dehydrogenase) transcription under strict anaerobic conditions, especially when using nitrate as a terminal electron acceptor. Purified alginate added to bacterial suspensions caused a decrease in growth, suggesting that alginate contributes to oxygen limitation for the organism and likely for patients afflicted with the inherited autosomal disease cystic fibrosis.

  5. Effect of the alginate composition on the biocompatibility of alginate-polylysine microcapsules

    NARCIS (Netherlands)

    DeVos, P; DeHaan, B; VanSchilfgaarde, R

    Alginate-polylysine (PLL) capsules are commonly applied for immunoprotection of endocrine tissues. Alginate is composed of mannuronic acid (M) and guluronic acid (G). Different types of alginate have different ratios of G to M, but little is known of the influence of these differences on

  6. Safety and Efficacy of Alginate Adhesion Barrier Gel in Compromised Intestinal Anastomosis.

    Science.gov (United States)

    Chaturvedi, Ankit A; Yauw, Simon T K; Lomme, Roger M L M; Hendriks, Thijs; van Goor, Harry

    For any anti-adhesive barrier developed for abdominal surgery, the use under conditions in which anastomotic healing is compromised needs to be investigated. The current study evaluates the effect of a new ultrapure alginate gel on early healing of high-risk anastomoses in the ileum and compares this with the gold standard used in clinical practice. In 75 adult male Wistar rats, a 5 mm ileal segment was resected and continuity was restored by construction of an inverted anastomosis. Rats were divided randomly into a control group and groups receiving either alginate gel or a sodium hyaluronate carboxymethylcellulose (HA/CMC) film around the anastomosis (n = 25 each). Carprofen, given in a daily dose of 1.25 mg/kg, was used to compromise anastomotic healing. At day three, animals were killed and scored for signs of anastomotic leakage and the presence of adhesions. The incidence of adhesion formation was 95% in the HA/CMC film group, which was significantly higher than in the controls (64%, p = 0.010) and the alginate gel group (52%, p = 0.004). The adhesion score was nearly 40% lower in the alginate gel group compared with the HA/CMC film group. The incidence of ileal leakage in the HA/CMC film group (92%) was significantly higher than in the controls (68%, p = 0.016). Leakage rate did not differ between the alginate gel and control groups. There was no significant difference between groups in either incision bursting pressure or incision breaking strength. Ultrapure alginate gel does not interfere with repair of ileal anastomoses constructed under conditions in which chances of anastomotic dehiscence are high. The alginate gel performs better than the HA/CMC film.

  7. 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. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Non-Invasive Evaluation of Alginate/Poly-L-lysine/Alginate Microcapsules by Magnetic Resonance Microscopy

    OpenAIRE

    Constantinidis, Ioannis; Grant, Samuel C.; Celper, Susanne; Gauffin-Holmberg, Isabel; Agering, Kristina; Oca-Cossio, Jose A.; Bui, Jonathan D.; Flint, Jeremy; Hamaty, Christine; Simpson, Nicholas E.; Blackband, Stephen J.

    2007-01-01

    In this report, we present data to demonstrate the utility of 1H MR microscopy to noninvasively examine alginate/poly-L-lysine/alginate (APA) microcapsules. Specifically, high-resolution images were used to visualize and quantify the poly-L-lysine (PLL) layer, and monitor temporal changes in the alginate gel microstructure during a month long in vitro culture. The thickness of the alginate/PLL layer was quantified to be 40.6±6.2 μm regardless of the alginate composition used to generate the b...

  9. 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)

  10. Alginate Biosynthesis Factories in Pseudomonas fluorescens: Localization and Correlation with Alginate Production Level

    Science.gov (United States)

    Maleki, Susan; Almaas, Eivind; Zotchev, Sergey; Valla, Svein

    2015-01-01

    Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner and outer membranes. In the present study, we developed a method by which the porin AlgE was detected by immunogold labeling and transmission electron microscopy. Localization of the AlgE protein was found to depend on the presence of other proteins in the multiprotein complex. No correlation was found between the number of alginate factories and the alginate production level, nor were the numbers of these factories affected in an algC mutant that is unable to produce the precursor needed for alginate biosynthesis. Precursor availability and growth phase thus seem to be the main determinants for the alginate production rate in our strain. Clustering analysis demonstrated that the alginate multiprotein complexes were not distributed randomly over the entire outer cell membrane surface. PMID:26655760

  11. Formulation of Sodium Alginate Nanospheres Containing ...

    African Journals Online (AJOL)

    Purpose: The aim of this work was to formulate sodium alginate nanospheres of amphotericin B by controlled gellification method and to evaluate the role of the nanospheres as a “passive carrier” in targeted antifungal therapy. Methods: Sodium alginate nanospheres of amphotericin B were prepared by controlled ...

  12. Drying and Rehydration of Calcium Alginate Gels

    NARCIS (Netherlands)

    Vreeker, R.; Li, L.; Fang, Y.; Appelqvist, I.; Mendes, E.

    2008-01-01

    In this paper, we study the rehydration properties of air-dried calcium alginate gel beads. Rehydration is shown to depend on alginate source (i.e. mannuronic to guluronic acid ratio) and the salt concentration in the rehydration medium. Rehydration curves are described adequately by the empirical

  13. Engineering alginate for intervertebral disc repair

    NARCIS (Netherlands)

    Bron, Johannes L.; Vonk, Lucienne A.; Smit, Theodoor H.; Koenderink, Gijsje H.

    2011-01-01

    Alginate is frequently studied as a scaffold for intervertebral disc (IVD) repair, since it closely mimics mechanical and cell-adhesive properties of the nucleus pulposus (NP) of the IVD. The aim of this study was to assess the relation between alginate concentration and scaffold stiffness and find

  14. 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.

  15. Preparation of Alginate Gel Beads Containing Metformin ...

    African Journals Online (AJOL)

    A new emulsion gelation method was used to prepare gel beads for a highly water-soluble drug metformin hydrochloride using sodium alginate as the polymer. The gel beads containing oil was prepared by gently mixing or homogenizing oil and water phase containing sodium alginate which was then extruded into calcium ...

  16. Method Designed To Detect Alginate-Degrading Bacteria

    OpenAIRE

    Kitamikado, Manabu; Yamaguchi, Kuniko; Tseng, Chao-Huang; Okabe, Bun'Ichi

    1990-01-01

    A simple turbidimetric method was developed to detect alginate degradation. Bacteria were grown in alginate-containing media, and culture fluids were mixed with an acidic albumin solution. Failure to develop a white turbidity indicated an alginate degrader. The method showed alginate degradation by Vibrio alginolyticus ATCC 17749, in contrast to prior descriptions.

  17. Evaluation of Alginate Microcapsules for Use in Transplantation of Islets of Langerhans

    OpenAIRE

    King, Aileen

    2001-01-01

    Transplantation of islets of Langerhans is a potential treatment of type 1 diabetes that aims to restore normal glucose homeostasis. Microencapsulation of islets could enable transplantation in the absence of immunosuppression, which would be beneficial as the side effects associated with immunosuppression outweigh the potential benefits of islet transplantation. Alginate is a polysaccharide that can be harvested from brown algae and is often used for microencapsulation of cells. The aim of t...

  18. Alginate-modifying enzymes: Biological roles and biotechnological uses

    Directory of Open Access Journals (Sweden)

    Helga eErtesvåg

    2015-05-01

    Full Text Available Alginate denotes a group of industrially important 1-4-linked biopolymers composed of the C-5-epimers β-D-mannuronic acid (M and α-L-guluronic acid (G. The polysaccharide is manufactured from brown algae where it constitutes the main structural cell wall polymer. The physical properties of a given alginate molecule, e.g. gel-strength, water-binding capacity, viscosity and biocompatibility, are determined by polymer length, the relative amount and distribution of G residues and the acetyl content, all of which are controlled by alginate modifying enzymes. Alginate has also been isolated from some bacteria belonging to the genera Pseudomonas and Azotobacter, and bacterially synthesized alginate may be O-acetylated at O-2 and/or O-3. Initially, alginate is synthesized as polymannuronic acid, and some M residues are subsequently epimerized to G residues. In bacteria a mannuronan C-5-epimerase (AlgG and an alginate acetylase (AlgX are integral parts of the protein complex necessary for alginate polymerisation and export. All alginate-producing bacteria use periplasmic alginate lyases to remove alginate molecules aberrantly released to the periplasm. Alginate lyases are also produced by organisms that utilize alginate as carbon source. Most alginate-producing organisms encode more than one mannuronan C-5 epimerase, each introducing its specific pattern of G residues. Acetylation protects against further epimerization and from most alginate lyases. One enzyme with alginate deacetylase activity from Pseudomonas syringae has been reported. Functional and structural studies reveal that alginate lyases and epimerases have related enzyme mechanisms and catalytic sites. Alginate lyases are now utilized as tools for alginate characterization. Secreted epimerases have been shown to function well in vitro, and have been engineered further in order to obtain enzymes that can provide alginates with new and desired properties for use in medical and

  19. Encapsulation of cells in alginate gels.

    Science.gov (United States)

    Sánchez, Pello; Hernández, Rosa María; Pedraz, José Luis; Orive, Gorka

    2013-01-01

    Cell microencapsulation is based on the immobilization of cells for continuous release of therapeutics. This approach has been tested in the treatment of many diseases and several clinical trials have been performed. Factors such as the choice of cells to be encapsulated, the biomaterial used, and the procedure for carrying out the capsules are important issues when implementing this technology.This book chapter makes a comprehensive description of alginate, the most frequently employed biomaterial, passing by its structure, the extraction and treatment, and finishing with the process of gelation. It also describes the various modifications that can be carried out to allow the interaction between the alginate and the integrin receptors of encapsulated cells. The main microencapsulation technologies are presented as well as how 100 μm alginate-Poly-L-Lysine-alginate microcapsules can be fabricated with Flow-focusing technology.

  20. [Progress of alginate-based biomedical materials].

    Science.gov (United States)

    Wei, Xiaojuan; Xi, Tingfei; Gu, Qisheng; Zheng, Yufeng

    2013-08-01

    To review the current situation of alginate-based biomedical materials, especially focus on the clinical strategies and research progress in the clinical applications and point out several key issues that should be concerned about. Based on extensive investigation of domestic and foreign alginate-based biomedical materials research and related patent, literature, and medicine producted, the paper presented the comprehensive analysis of its research and development, application status, and then put forward several new research directions which should be focused on. Alginate-based biomedical materials have been widely used in clinical field with a number of patients, but mainly in the fields of wound dressings and dental impression. Heart failure treatment, embolization, tissue engineering, and stem cells culture are expected to become new directions of research and products development. Development of alginate-based new products has good clinical feasibility and necessity, but a lot of applied basic researches should be carried out in the further investigations.

  1. Alginate dressing as a donor site haemostat.

    OpenAIRE

    Groves, A. R.; Lawrence, J. C.

    1986-01-01

    An alginate fibre dressing has been used to reduce blood loss from skin graft donor sites. Significant haemostasis has been achieved in the immediate post surgery phase and no adverse reactions observed.

  2. Stability of alginate microbead properties in vitro

    Science.gov (United States)

    Moya, Monica L.; Morley, Michael; Khanna, Omaditya; Opara, Emmanuel C.

    2013-01-01

    Alginate microbeads have been investigated clinically for a number of therapeutic interventions, including drug delivery for treatment of ischemic tissues, cell delivery for tissue regeneration, and islet encapsulation as a therapy for type I diabetes. The physical properties of the microbeads play an important role in regulating cell behavior, protein release, and biological response following implantation. In this research alginate microbeads were synthesized, varying composition (mannuronic acid to guluronic acid ratio), concentration of alginate and needle gauge size. Following synthesis, the size, volume fraction, and morphometry of the beads were quantified. In addition, these properties were monitored over time in vitro in the presence of varying calcium levels in the microenvironment. The initial volume available for solute diffusion increased with alginate concentration and mannuronic (M) acid content, and bead diameter decreased with M content but increased with needle diameter. Interestingly, microbeads eroded completely in saline in less than 3 weeks regardless of synthesis conditions much faster than what has been observed in vivo. However, microbead stability was increased by the addition of calcium in the culture medium. Beads synthesized with low alginate concentration and high G content exhibited a more rapid change in physical properties even in the presence of calcium. These data suggest that temporal variations in the physical characteristics of alginate microbeads can occur in vitro depending on synthesis conditions and microbead environment. The results presented here will assist in optimizing the design of the materials for clinical application in drug delivery and cell therapy. PMID:22350778

  3. In vitro and in vivo evaluation of alginate and alginate- chitosan ...

    African Journals Online (AJOL)

    Keywords: Alginate, Beads, Chitosan, Metformin, Diabetes, In vivo study. Tropical ... Diabetes, and the American Diabetes. Association as the first line therapy for Type 2 diabetes [2,3]. Following oral administration, the drug is mainly absorbed from the upper small intestine ..... HCl-loaded fenugreek seed mucilage alginate.

  4. Production of Alginate Oligosaccharides (AOS as Prebiotic Ingredients through by Alginate lyase enzyme

    Directory of Open Access Journals (Sweden)

    Fahriza Sri Afni

    2017-04-01

    Full Text Available Prebiotics is indigestible foods that can not be digested but can stimulate the growth and activity of bacteria in the digestive tract effecting human health. Alginate oligosaccharides (AOS can be used as a source of prebiotic. That compounds can be produced enzymatically by cutting long chain alginates using alginate lyase. The aim of this study was to produce alginate lyase enzyme then producing Alginate oligosaccharides (AOS as a prebiotic ingredients. The alginate lyase enzyme can be produced from Bacillus megaterium bacteria using a discontinuous fermentor. The enzyme was  optimum temperature of 45°C and an optimum pH of 7.0. Alginate oligosaccharides production was performed with the addition of different enzyme concentrations 25, 50, 75, and 100 U. The result of the addition of enzyme (25, 50,75 U showed that the value of polymerization degrees (DP were between 4-5. However, the addition of enzyme (100 U was in the range of  DP 3-4. Bacterial probiotic growth test results of Bifidobacteria and Lactobacillus showed that 1% added AOS media were able to increase the growth of probiotic bacteria compared to themedia without addition of AOS. The addition Alginate lyase activity of 50 U in AOS production is the best treatment of both probiotic bacteria.

  5. 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.

  6. Pengaruh Waktu Pengisian Cetakan Alginate Terhadap Ketepatan Model Hasil Cetakan

    OpenAIRE

    Suhailatun Nasifah Rangkuti

    2008-01-01

    Bahan cetak alginate sampai sekarang masih banyak digunakan di Kedokteran Gigi dengan alasan penanganannya mudah, alat yang dipergunakan relatif sederhana, elastis, cukup akurat dan relatif lebih murah. Umumnya komposisi alginate terdiri dari polasturn alginate, diatomaceus earth, zinc oxide, kalsium sulfaty potasium sulfat, sodium fo&fat, glikol serta bahan pewangi. Tiap komponen mempunyai fungsi tertentu dan mempengaruhi sifat-sifat bahan cetak alginate. Dalam pemanipulasian bahan ...

  7. Versatile click alginate hydrogels crosslinked via tetrazine–norbornene chemistry

    OpenAIRE

    Desai, Rajiv; Koshy, Sandeep Tharian; Hilderbrand, Scott A.; Mooney, David J.; Joshi, Neel S.

    2015-01-01

    Alginate hydrogels are well-characterized, biologically inert materials that are used in many biomedical applications for the delivery of drugs, proteins, and cells. Unfortunately, canonical covalently crosslinked alginate hydrogels are formed using chemical strategies that can be biologically harmful due to their lack of chemoselectivity. In this work we introduce tetrazine and norbornene groups to alginate polymer chains and subsequently form covalently crosslinked click alginate hydrogels ...

  8. An effect of alginate on the stability of LDH nanosheets in aqueous solution and preparation of alginate/LDH nanocomposites.

    Science.gov (United States)

    Kang, Hongliang; Shu, Yang; Li, Zhuang; Guan, Bo; Peng, Shunjin; Huang, Yong; Liu, Ruigang

    2014-01-16

    Nanosheets under 10nm in thickness are obtained by exfoliating layered double hydroxide (LDH) in formamide. The LDH nanosheets are dispersed and stabilized in an alginate aqueous solution after removing formamide by water washing and ultracentrifugation. During the water washing stage LDH nanosheets can be prevented from restacking by electrostatic stabilization of the surface of LDH sheets through the adsorption of alginate. Alginate/LDH nanocomposites can be prepared by drying the dispersion, and sandwich-like structures in the nanocomposites are formed with two alginate layers contained between two LDH sheets. LDH nanosheets in the dried alginate/LDH nanocomposites can be re-dispersed in water. The thermal stability of alginate in the nanocomposite is increased by LDH. Alginate membranes containing this layered nanocomposite can be prepared. The addition of LDH into the alginate matrix leads to an increase in the mechanical properties of the nanocomposite. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Development of Alginate/Chitosan Microparticles for Dust Mite ...

    African Journals Online (AJOL)

    Erah

    Conclusion: This study indicates that alginate and alginate-coated chitosan microparticles are safe and can be further developed for mucosal ... properties. Additionally, chitosan micro/nanoparticles can be easily prepared by ionic ... obstacles is by coating an acid-resistant polymer, such as sodium alginate, onto the.

  10. Falsirhodobacter sp. alg1 Harbors Single Homologs of Endo and Exo-Type Alginate Lyases Efficient for Alginate Depolymerization

    OpenAIRE

    Mori, Tetsushi; Takahashi, Mami; Tanaka, Reiji; Miyake, Hideo; Shibata, Toshiyuki; Chow, Seinen; Kuroda, Kouichi; Ueda, Mitsuyoshi; Takeyama, Haruko

    2016-01-01

    Alginate-degrading bacteria play an important role in alginate degradation by harboring highly efficient and unique alginolytic genes. Although the general mechanism for alginate degradation by these bacteria is fairly understood, much is still required to fully exploit them. Here, we report the isolation of a novel strain, Falsirhodobacter sp. alg1, the first report for an alginate-degrading bacterium from the family Rhodobacteraceae. Genome sequencing reveals that strain alg1 harbors a prim...

  11. Alginate Lyases from Alginate-Degrading Vibrio splendidus 12B01 Are Endolytic

    Science.gov (United States)

    Badur, Ahmet H.; Jagtap, Sujit Sadashiv; Yalamanchili, Geethika; Lee, Jung-Kul; Zhao, Huimin

    2015-01-01

    Alginate lyases are enzymes that degrade alginate through β-elimination of the glycosidic bond into smaller oligomers. We investigated the alginate lyases from Vibrio splendidus 12B01, a marine bacterioplankton species that can grow on alginate as its sole carbon source. We identified, purified, and characterized four polysaccharide lyase family 7 alginates lyases, AlyA, AlyB, AlyD, and AlyE, from V. splendidus 12B01. The four lyases were found to have optimal activity between pH 7.5 and 8.5 and at 20 to 25°C, consistent with their use in a marine environment. AlyA, AlyB, AlyD, and AlyE were found to exhibit a turnover number (kcat) for alginate of 0.60 ± 0.02 s−1, 3.7 ± 0.3 s−1, 4.5 ± 0.5 s−1, and 7.1 ± 0.2 s−1, respectively. The Km values of AlyA, AlyB, AlyD, and AlyE toward alginate were 36 ± 7 μM, 22 ± 5 μM, 60 ± 2 μM, and 123 ± 6 μM, respectively. AlyA and AlyB were found principally to cleave the β-1,4 bonds between β-d-mannuronate and α-l-guluronate and subunits; AlyD and AlyE were found to principally cleave the α-1,4 bonds involving α-l-guluronate subunits. The four alginate lyases degrade alginate into longer chains of oligomers. PMID:25556193

  12. Biochemical Characteristics and Variable Alginate-Degrading Modes of a Novel Bifunctional Endolytic Alginate Lyase.

    Science.gov (United States)

    Cheng, Yuanyuan; Wang, Dandan; Gu, Jingyan; Li, Junge; Liu, Huihui; Li, Fuchuan; Han, Wenjun

    2017-12-01

    Bifunctional alginate lyases can efficiently degrade alginate comprised of mannuronate (M) and guluronate (G), but their substrate-degrading modes have not been thoroughly elucidated to date. In this study, we present Aly1 as a novel bifunctional endolytic alginate lyase of the genus Flammeovirga The recombinant enzyme showed optimal activity at 50°C and pH 6.0. The enzyme produced unsaturated disaccharide (UDP2) and trisaccharide fractions as the final main alginate digests. Primary substrate preference tests and further structure identification of various size-defined final oligosaccharide products demonstrated that Aly1 is a bifunctional alginate lyase and prefers G to M. Tetrasaccharide-size fractions are the smallest substrates, and M, G, and UDP2 fractions are the minimal product types. Remarkably, Aly1 can vary its substrate-degrading modes in accordance with the terminus types, molecular sizes, and M/G contents of alginate substrates, producing a series of small size-defined saturated oligosaccharide products from the nonreducing ends of single or different saturated sugar chains and yielding unsaturated products in distinct but restricted patterns. The action mode changes can be partially inhibited by fluorescent labeling at the reducing ends of oligosaccharide substrates. Deletion of the noncatalytic region (NCR) of Aly1 caused weak changes of biochemical characteristics but increased the degradation proportions of small size-defined saturated M-enriched oligosaccharide substrates and unsaturated tetrasaccharide fractions without any size changes of degradable oligosaccharides, thereby enhancing the M preference and enzyme activity. Therefore, our results provided insight into the variable action mode of a novel bifunctional endolytic alginate lyase to inform accurate enzyme use.IMPORTANCE The elucidated endolytic alginate lyases usually degrade substrates into various size-defined unsaturated oligosaccharide products (≥UDP2), and exolytic enzymes

  13. New insights into Pseudomonas fluorescens alginate biosynthesis relevant for the establishment of an efficient production process for microbial alginates.

    Science.gov (United States)

    Maleki, Susan; Mærk, Mali; Hrudikova, Radka; Valla, Svein; Ertesvåg, Helga

    2017-07-25

    Alginate denotes a family of linear polysaccharides with a wide range of industrial and pharmaceutical applications. Presently, all commercially available alginates are manufactured from brown algae. However, bacterial alginates have advantages with regard to compositional homogeneity and reproducibility. In order to be able to design bacterial strains that are better suited for industrial alginate production, defining limiting factors for alginate biosynthesis is of vital importance. Our group has been studying alginate biosynthesis in Pseudomonas fluorescens using several complementary approaches. Alginate is synthesised and transported out of the cell by a multiprotein complex spanning from the inner to the outer membrane. We have developed an immunogold labelling procedure in which the porin AlgE, as a part of this alginate factory, could be detected by transmission electron microscopy. No time-dependent correlation between the number of such factories on the cell surface and alginate production level was found in alginate-producing strains. Alginate biosynthesis competes with the central carbon metabolism for the key metabolite fructose 6-phosphate. In P. fluorescens, glucose, fructose and glycerol, are metabolised via the Entner-Doudoroff and pentose phosphate pathways. Mutational analysis revealed that disruption of the glucose 6-phosphate dehydrogenase gene zwf-1 resulted in increased alginate production when glycerol was used as carbon source. Furthermore, alginate-producing P. fluorescens strains cultivated on glucose experience acid stress due to the simultaneous production of alginate and gluconate. The combined results from our studies strongly indicate that the availability of fructose 6-phosphate and energy requires more attention in further research aimed at the development of an optimised alginate production process. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Storage duration effect on deformation recovery of repacked alginates

    Directory of Open Access Journals (Sweden)

    Siti Sunarintyas

    2009-09-01

    Full Text Available Background: Manufacturers supply alginate impression materials as a powder that is packaged in bulk and in individual container. Some Indonesian dental suppliers often repackage the bulk alginate into individual plastic packages which are not tied tightly and stored in the display room without air conditioner. It is known that critical factors to the shelf life of alginate includer avoidance of moisture contamination which may lead to premature setting of the alginate and avoidance of high temperature which may cause depolymerization of the alginate. Purpose: The aim of this study was to determine storage duration effect of repacked alginates on deformation recovery. Methods: Two brands of alginates (Tulip®TU, and Aroma Fine DF III®AF were repacked into 120 plastic containers. The samples were stored in room condition (temperature 29° C ± 1° C, relative humidity 60% ± 10% for 1, 2, 3, 4 and 5 weeks. The alginates setting time and recovery from deformation were measured according to the ANSI/ADA specification number 18 (ISO 1563. result: The results revealed that there was decreased setting time during 5 weeks but there was slight decreased in deformation recovery after 3 weeks storage. The ANOVA showed there was no significant difference of alginates deformation recovery among the storage times (p > 0.05. Conclusion: Storage duration of repacked alginates in plastic containers during 5 weeks in room condition do not influence the alginate deformation recovery.

  15. Physicochemical properties of marine collagen-alginate biomaterial

    Science.gov (United States)

    Soon, K. S.; Hii, S. L.; Wong, C. L.; Leong, L. K.; Woo, K. K.

    2017-12-01

    Collagen base biomaterials are widely applied in the field of tissue engineering. However, these fibrous proteins in animal connective tissues are insufficient to fulfill the mechanical properties for such applications. Therefore, alginate as a natural polysaccharide was incorporated. In this study, Smooth wolf herring skins was collected from the local fish ball processing industry for collagen extraction using acid solubilisation method. On the other hand, alginate from brown seaweed (Sargassum polycystum) was extracted with calcium carbonate at 50 °C. The composite films of different collagen and alginate ratio were prepared by lyophilisation with pure collagen film as control. The effects of alginate on swelling behaviour, porosity, collagenase degradation and tensile strength of the composite films were investigated. Swelling behaviour increased with alginate content, 50 % alginate film achieved 1254.75 % swelling after 24 h. All composite films achieved more than 80 % porosity except the film with 80 % collagen (65.41 %). Porosity was highest in 100 % alginate (94.30 %). Highest tensile strength (1585.87 kPa) and young modulus (27.05 MPa) was found in 50 % alginate film. In addition, resistance to collagenase degradation was improved with alginate content, lowest degradation rate was determined in 80 % alginate film. Results indicated alginate is efficient in improving some mechanical properties of the composite film.

  16. In vitro and in vivo evaluation of alginate and alginate- chitosan ...

    African Journals Online (AJOL)

    chitosan (AL-CS) beads for oral application and to evaluate their in vitro .... gelling medium at room temperature [18,19]. After filtration, the beads were also ..... metformin HCl through incorporation into stomach specific floating alginate beads.

  17. Usefulness of Alginate Lyases Derived from Marine Organisms for the Preparation of Alginate Oligomers with Various Bioactivities.

    Science.gov (United States)

    Takeshita, S; Oda, T

    Alginate-degrading enzyme, alginate lyase, catalyzes the cleavage of glycosidic 1-4 O-linkages between uronic acid residues of alginate by a β-elimination reaction leaving a 4-deoxy-l-erythro-hex-4-ene pyranosyluronate as nonreducing terminal end. The enzymes from a wide variety of sources such as marine molluscs, seaweeds, and marine bacteria have been discovered and studied not only from a point of view of enzymological interest of enzyme itself but also for elucidation of fine chemical structure of alginate, structure-activity relationship of alginate, and biological activities and physicochemical features of the enzymatic digestion products. Based on the substrate specificities, alginate lyases are classified into three groups: poly(β-d-mannuronate) lyase, poly(α-l-guluronate) lyase, and bifunctional alginate lyase, which are specific to mannuronate, guluronate, and both uronic acid residues, respectively. We have studied enzymological aspects of these three types of alginate lyases, and bioactivities of enzymatically digested alginate oligomers. In this chapter, we described the purification and characterization of three types of alginate lyases from different marine origins and overviewed the bioactivities of alginate oligomers. © 2016 Elsevier Inc. All rights reserved.

  18. Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast-An in vitro Study.

    Science.gov (United States)

    Madhavan, Ranjith; George, Navia; Thummala, Niharika R; Ravi, S V; Nagpal, Ajay

    2017-11-01

    For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with self-disinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Difference in surface hardness was statistically insignificant (p > 0.05). Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material.

  19. Development of sodium alginate and konkoli gumgrafted ...

    African Journals Online (AJOL)

    This experiment is a continuation of our effort to develop a blend membrane of sodium alginate and “konkoli” gum-g-polyacrylamide (KG-g-PAAm) for bioremediation of wastewater. The effect of graft reaction conditions on the percentage graft yield in the graft copolymerization was investigated. It was observed that grafting ...

  20. 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.

  1. Rusip with Alginate Addition as Seasoning

    Directory of Open Access Journals (Sweden)

    Dyah Koesoemawardani

    2017-02-01

    Full Text Available AbstractRusip was a fermented food of fish that have a distinctive aroma so that potential to be developed into instant seasoning. This research was aimed to optimize powder processing of rusip with the addition of alginate. The treatments were concentration of alginate (5% , 10% , 15% and 20% w/w and the heating temperature (50oC, 60oC , 70oC and 80oC. Data was analyzed using advanced test Honestly Significant Difference (HSD at 5% level. The results showed that the best rusip powder was alginate 5% with heating at 50oC and 70°C . The character were 5.98% and 7.57% water content; pH 5.69 and 5.85; 7.77% and 8.77% salt content; 28% and 27.65% protein content, respectively. This study proves that the addition of alginate 5% (w/w, heating at a temperature of 50oC and 70°C can trap volatile compounds formed during fermentation in rusip processing into powder.

  2. Adsorption of CO2 by alginate immobilized zeolite beads

    Science.gov (United States)

    Suratman, A.; Kunarti, E. S.; Aprilita, N. H.; Pamurtya, I. C.

    2017-03-01

    Immobilized zeolit in alginate beads for adsorption of CO2 was developed. Alginate immobilized zeolit beads was generated by dropping the mixture of Na-alginate and zeolite solution into Ca2+ solution. The adsorption efficacy such as the influence of contact time, mass of zeolite, flowrate of CO2, and mass of adsorbent was evaluated. The adsorption of CO2 onto alginate immobilized zeolit beads was investigated by performing both equilibrium and kinetic batch test. Bead was characterized by FTIR and SEM. Alginate immobilized zeolit beads demonstrated significantly higher sorption efficacy compared to plain alginate beads and zeolite with 0.25 mmol CO2 adsorbed /g adsorbent. Optimum condition was achieved with mass composition of alginate:zeolite (3:1), flowrate 50 mL/min for 20 minutes. The alginate immobilized zeolit beads showed that adsorption of CO2 followed Freundlich isotherm and pseudo second order kinetic model. Adsorption of CO2 onto alginate immobilized zeolite beads is a physisorption with adsorption energy of 6.37 kJ/mol. This results indicates that the alginate immobilized zeolit beads can be used as promising adsorbents for CO2.

  3. Alginate-polylysine-alginate microcapsules: effect of size reduction on capsule properties.

    Science.gov (United States)

    Strand, B L; Gåserød, O; Kulseng, B; Espevik, T; Skjåk-Baek, G

    2002-01-01

    Alginate-polylysine-alginate capsules containing insulin-producing cells have been used as a bio-artificial pancreas in the treatment of diabetes mellitus. In a search for microcapsules with improved diffusion characteristics, a high voltage system was developed that produces 250,000 beads/min with a diameter of 160 microm +/- 3-5%. The diameter of the beads could be varied between 160-700 microm depending on the needle diameter and construction, the voltage, the distance between the electrodes and the flow of alginate solution. Ca-alginate beads with diameters of 200 and 500 microm were produced by the high voltage electrostatic system. The 200 microm beads were sensitive to poly-L-lysine (PLL) exposure and had to be washed in ion-free solution to avoid collapse. The 200 microm beads swelled more than the 500 microm beads in the washing and PLL treatment. Also, the porosity of the capsules changed with size, but capsules impermeable to tumour necrosis factor (TNF) could be made by exchanging PLL with poly-D-lysine (PDL) for the 500 microm beads. The 200 microm beads were impermeable to IgG after PLL exposure. Islets of Langerhans were encapsulated in alginate-PLL-alginate capsules and evaluated by measuring protruding islets and insulin production. Islets in microcapsules made by the high voltage electrostatic system did not function differently from islets in larger microcapsules made by an air jet system. In conclusion, alginate capsules made by a high voltage electrostatic system enable large-scale production of small capsules with a narrow size distribution that can meet the functional properties of larger capsules by small changes in the encapsulation procedure.

  4. Falsirhodobacter sp. alg1 Harbors Single Homologs of Endo and Exo-Type Alginate Lyases Efficient for Alginate Depolymerization.

    Science.gov (United States)

    Mori, Tetsushi; Takahashi, Mami; Tanaka, Reiji; Miyake, Hideo; Shibata, Toshiyuki; Chow, Seinen; Kuroda, Kouichi; Ueda, Mitsuyoshi; Takeyama, Haruko

    2016-01-01

    Alginate-degrading bacteria play an important role in alginate degradation by harboring highly efficient and unique alginolytic genes. Although the general mechanism for alginate degradation by these bacteria is fairly understood, much is still required to fully exploit them. Here, we report the isolation of a novel strain, Falsirhodobacter sp. alg1, the first report for an alginate-degrading bacterium from the family Rhodobacteraceae. Genome sequencing reveals that strain alg1 harbors a primary alginate degradation pathway with only single homologs of an endo- and exo-type alginate lyase, AlyFRA and AlyFRB, which is uncommon among such bacteria. Subsequent functional analysis showed that both enzymes were extremely efficient to depolymerize alginate suggesting evolutionary interests in the acquirement of these enzymes. The exo-type alginate lyase, AlyFRB in particular could depolymerize alginate without producing intermediate products making it a highly efficient enzyme for the production of 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). Based on our findings, we believe that the discovery of Falsirhodobacter sp. alg1 and its alginolytic genes hints at the potentiality of a more diverse and unique population of alginate-degrading bacteria.

  5. [Diagnostic value of alginate test in gastroesophageal reflux disease].

    Science.gov (United States)

    Bordin, D S; Masharova, A A; Droxzdov, V N; Firsova, L D; Kozhurina, T S

    2010-01-01

    To evaluate the diagnostic accuracy of single dose of gaviscon (the alginates test) in detecting gastroesophageal reflux disease (GERD) in patients with heartburn symptoms. 123 patients (male 46, female 77, age 43.6 +/- 15.5 years) with symptoms suggestive of GERD were investigated. Symptom response to the alginates test compared in GERD positive and GERD negative patients according traditional diagnostic criteria of GERD (upper endoscopy, 24-hr pH-monitoring, esophageal manometry, response to treatment with PPIs). Of 91 (78.9%) patients with positive alginates test, 87 were classified as GERD positive and 4 as GERD negative. Of 32 (26%) patients with negative alginates test, 29 were GERD negative and 3 GERD positive. The results providing a sensitivity of alginates test of 96.7% and a specificity of 87.7%. The alginates test is sensitive and specific for diagnosing GERD in patients with typical GERD symptoms.

  6. 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)

  7. Variations in Calcium and Alginate Ions Concentration in Relation to the Properties of Calcium Alginate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hamed Daemi

    2013-05-01

    Full Text Available Alginate belongs to a group of natural polymers called polysaccharides. They have carboxylic functional groups beside hydroxyls which are common in all polysaccharides. These materials show interesting properties due to theirfunctional groups. One of these properties is the ability of this polymer as a suitable carrier of protecting and transferring drugs and biomolecules. The particle sizes of these polymers are very important for their applications, so different techniques were used for preparation of these materials. In this way polymeric nanoparticles of calcium alginate which are excellent carriers in drug delivery systems were prepared by addition of calcium chloride solution to dilute solution of sodium alginate. Investigation of the size and distribution of nanoparticles were analyzed by SEM method. The concentration effects of both alginate and calcium ions on the size and distribution of  nanoparticles were studied in this research. Results showed that the size of nanoparticles obviously decreased with decreasing polymeric alginate concentration because of lower active sites in polymer chain. On the other hand, thesize and distribution of nanoparticles are significantly improved with increase of calcium cation concentrations. The mean particle size 40-70 nm and spherical shape are the main characteristics of the prepared nanoparticles.

  8. Alginate Encapsulation of Human Hepatocytes and Assessment of Microbeads.

    Science.gov (United States)

    Mitry, Ragai R; Jitraruch, Suttiruk; Iansante, Valeria; Dhawan, Anil

    2017-01-01

    Alginate encapsulation of cells is an attractive technique in which alginate becomes polymerized entrapping the cells. The structure of formed microbeads/microcapsules is semipermeable as it allows oxygen and nutrients to go in, and waste products and other materials produced by the cells to go out. Here, we describe basic protocols for alginate encapsulation of human hepatocytes and methods for assessing the microbeads produced.

  9. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    Science.gov (United States)

    Zhai, Peng; Chen, X B; Schreyer, David J

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Versatile click alginate hydrogels crosslinked via tetrazine-norbornene chemistry.

    Science.gov (United States)

    Desai, Rajiv M; Koshy, Sandeep T; Hilderbrand, Scott A; Mooney, David J; Joshi, Neel S

    2015-05-01

    Alginate hydrogels are well-characterized, biologically inert materials that are used in many biomedical applications for the delivery of drugs, proteins, and cells. Unfortunately, canonical covalently crosslinked alginate hydrogels are formed using chemical strategies that can be biologically harmful due to their lack of chemoselectivity. In this work we introduce tetrazine and norbornene groups to alginate polymer chains and subsequently form covalently crosslinked click alginate hydrogels capable of encapsulating cells without damaging them. The rapid, bioorthogonal, and specific click reaction is irreversible and allows for easy incorporation of cells with high post-encapsulation viability. The swelling and mechanical properties of the click alginate hydrogel can be tuned via the total polymer concentration and the stoichiometric ratio of the complementary click functional groups. The click alginate hydrogel can be modified after gelation to display cell adhesion peptides for 2D cell culture using thiol-ene chemistry. Furthermore, click alginate hydrogels are minimally inflammatory, maintain structural integrity over several months, and reject cell infiltration when injected subcutaneously in mice. Click alginate hydrogels combine the numerous benefits of alginate hydrogels with powerful bioorthogonal click chemistry for use in tissue engineering applications involving the stable encapsulation or delivery of cells or bioactive molecules. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 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.

  12. Amphiphilic Alginates for Marine Antifouling Applications.

    Science.gov (United States)

    Jakobi, Victoria; Schwarze, Jana; Finlay, John A; Nolte, Kim A; Spöllmann, Stephan; Becker, Hans-Werner; Clare, Anthony S; Rosenhahn, Axel

    2018-02-12

    Amphiphilic polymers are promising candidates for novel fouling-release coatings for marine applications. We grafted amphiphilic alginates with fluorinated side chains to glass and silicon substrates and characterized the obtained films by contact angle goniometry, spectroscopic ellipsometry, XPS, and ATR-FTIR. The potential to inhibit protein attachment was tested against four different proteins, and intermediate fluorine loadings showed the strongest reduction with respect to hydrophobic, aliphatic controls. A similar trend was observed in dynamic attachment experiments using Navicula perminuta diatoms and settlement experiments with zoospores of the green algae Ulva linza. The results indicate that amphiphilic alginates are promising natural and renewable biomacromolecules that could be included in future protective coating technologies.

  13. Covalent stabilization of alginate hydrogel beads via Staudinger ligation: Assessment of poly(ethylene glycol) and alginate cross-linkers

    OpenAIRE

    Gattás-Asfura, Kerim M.; Fraker, Christopher A.; Stabler, Cherie L.

    2011-01-01

    Cellular encapsulation within alginate hydrogel capsules has broad applications in tissue engineering. In seeking to improve the inherent instability of ionically cross-linked alginate hydrogels, we previously demonstrated the covalent stabilization of Ba2+ cross-linked alginate-azide beads via chemoselective Staudinger ligation using a 1-methyl-2-diphenylphosphino-terephthalate (MDT) terminated poly(ethylene glycol) linker. In this study, we functionalized variant PEG, linear and branched, a...

  14. 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.

  15. The compartmented alginate fibres optimisation for bitumen rejuvenator encapsulation

    NARCIS (Netherlands)

    Tabaković, Amir; Copuroglu, O.; Post, W.; Garcia Espallargas, Santiago J.; Schlangen, H.E.J.G.

    2017-01-01

    This article presents development of a novel self-healing technology for asphalt pavements, where asphalt binder rejuvenator is encapsulated within the compartmented alginate fibres. The key objective of the study was to optimise the compartmented alginate fibre design, i.e., maximising amount of

  16. Comparison Of The Dimensional Stability Of Alginate Impressions ...

    African Journals Online (AJOL)

    Objective: To determine and compare the dimensional stability of alginate impressions disinfected with Sodium hypochlorite using the spray and immersion methods. Methodology: Alginate impressions of a master model of truncated metal cones were made and disinfected with 1% sodium hypochlorite constituted from ...

  17. Alginate Nanospheres Prepared by Internal or External Gelation with Nanoparticles

    NARCIS (Netherlands)

    Paques, J.P.

    2015-01-01

    Alginate is a biodegradable polymer that can be used for the formation of nanospheres with applications in food, biomedicine, and biotechnology. Alginate gels in mild conditions, and does not require organic solvents for the formation of nanospheres. This makes them ideal for entrapment of sensitive

  18. Properties of advanced (reduced) graphene oxide-alginate biopolymer films

    NARCIS (Netherlands)

    Vilcinskas, K.

    2016-01-01

    In this work, properties of Calcium alginate-reduced graphene oxide and Barium alginate‐reduced graphene oxide composite films are explored. In addition, the properties of the divalent metal ion-cross-linked alginate composite films are compared to the analogous properties of uncross‐linked Sodium

  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. Alginate derivatization: a review of chemistry, properties and applications.

    Science.gov (United States)

    Pawar, Siddhesh N; Edgar, Kevin J

    2012-04-01

    Alginates have become an extremely important family of polysaccharides because of their utility in preparing hydrogels at mild pH and temperature conditions, suitable for sensitive biomolecules like proteins and nucleic acids, and even for living cells such as islets of Langerhans. In addition, the complex monosaccharide sequences of alginates, and our growing ability to create controlled sequences by the action of isolated epimerases upon the alginate precursor poly(mannuronic acid), create remarkable opportunities for understanding the relationship of properties to sequence in natural alginates (control of monosaccharide sequence being perhaps the greatest synthetic challenge in polysaccharide chemistry). There is however a trend in recent years to create "value-added" alginates, by performing derivatization reactions on the polysaccharide backbone. For example, chemical derivatization may enable alginates to achieve enhanced hydroxyapatite (HAP) nucleation and growth, heparin-like anticoagulation properties, improved cell-surface interactions, degradability, or tuning of the hydrophobic-hydrophilic balance for optimum drug release. The creation of synthetic derivatives therefore has the potential to empower the next generation of applications for alginates. Herein we review progress towards controlled synthesis of alginate derivatives, and the properties and applications of these derivatives. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. A novel wound dressing material—fibrin–chitosan–sodium alginate ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 35; Issue 7. A novel wound dressing material — fibrin–chitosan–sodium alginate composite sheet ... FTIR spectrum confirmed the interaction between amino groups of chitosan, fibrin and sodium alginate and SEM studies revealed composite nature of the material.

  2. 21 CFR 172.858 - Propylene glycol alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or “propylene...

  3. Composition dependent properties of graphene (oxide)-alginate biopolymer nanocomposites

    NARCIS (Netherlands)

    Vilcinskas, K.; Jansen, K.M.B.; Mulder, F.M.; Picken, S.J.; Koper, G.J.M.

    2016-01-01

    We report on the thermal, electrical, and mechanical properties of alginate biopolymer nanocomposites prepared by solution casting with various amounts of graphene oxide (GO) or reduced GO (rGO). Our data shows that the thermal stability of alginate nanocomposites can be improved by the

  4. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Applications of Alginate-Based Bioinks in 3D Bioprinting

    Science.gov (United States)

    Axpe, Eneko; Oyen, Michelle L.

    2016-01-01

    Three-dimensional (3D) bioprinting is on the cusp of permitting the direct fabrication of artificial living tissue. Multicellular building blocks (bioinks) are dispensed layer by layer and scaled for the target construct. However, only a few materials are able to fulfill the considerable requirements for suitable bioink formulation, a critical component of efficient 3D bioprinting. Alginate, a naturally occurring polysaccharide, is clearly the most commonly employed material in current bioinks. Here, we discuss the benefits and disadvantages of the use of alginate in 3D bioprinting by summarizing the most recent studies that used alginate for printing vascular tissue, bone and cartilage. In addition, other breakthroughs in the use of alginate in bioprinting are discussed, including strategies to improve its structural and degradation characteristics. In this review, we organize the available literature in order to inspire and accelerate novel alginate-based bioink formulations with enhanced properties for future applications in basic research, drug screening and regenerative medicine. PMID:27898010

  6. [PROGRESS OF ALGINATE DERIVATIVES BASED ON BIOMEDICAL MATERIALS].

    Science.gov (United States)

    Wei, Xiaojuan; Gu, Qisheng; Wang, Qingsheng; Xiao, Jimin

    2015-04-01

    To summarize the current research status of alginate derivatives based on biomedical materials, and analyze several key points as novel clinical products. The general preparation and application methods of alginate derivatives based on biomedical materials at home and abroad were reviewed. The present status and problems were analyzed. The derivation methods to prepare alginate derivatives include crosslink, sulfation, biological factors derivatization, hydrophobic modification, and graft copolymerization. With excellent bionic performance of structure and properties, many alginate derivatives are available for tissue engineering scaffolds, artificial organs, and drug delivery systems etc. However, more systematic applied basic research data should be collected and statistically analyzed for risk managements. Alginate derivatives have good feasibility as novel medical products, meanwhile, systematic evaluation and verification should be executed for their safety, effectiveness, and suitability.

  7. Synthesis and antimicrobial properties of Zn-mineralized alginate nanocomposites.

    Science.gov (United States)

    Malagurski, Ivana; Levic, Steva; Pantic, Milena; Matijasevic, Danka; Mitric, Miodrag; Pavlovic, Vladimir; Dimitrijevic-Brankovic, Suzana

    2017-06-01

    New bioactive and antimicrobial biomaterials were produced by alginate-mediated biomineralization with Zn-mineral phase. The synthesis procedure is simple, cost-effective and resulted in two different Zn-mineralized alginate nanocomposites, Zn-carbonate/Zn-alginate and Zn-phosphate/Zn-alginate. The presence of Zn-mineral phase and its type, have significantly affected nanocomposite morphology, stability, total metallic loading and potential to release Zn(II) in physiological environment. Antimicrobial experiments showed that both types of Zn-mineralized nanocomposites exhibit strong antimicrobial effect against Escherichia coli, Staphylococcus aureus and Candida albicans. These results suggest that alginate biomineralization, where minerals are salts of essential metallic ions like Zn(II), represents a good strategy for designing multifunctional biomaterials for potential biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. One Pot Synthesis and Characterization of Alginate Stabilized Semiconductor Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sundarrajan, Parani; Eswaran, Prabakaran; Marimuthu, Alexander; Subhadra, Lakshmi Baddireddi; Kannaiyan, Pandian [Univ., of Madras, Chennai (India)

    2012-10-15

    Uniform and well dispersed metal sulfide semiconductor nanoparticles incorporated into matrices of alginate biopolymer are prepared by using a facile in situ method. The reaction was accomplished by impregnation of alginate with divalent metal ions followed by reaction with thioacetamide. XRD analysis showed that the nanoparticles incorporated in the polymer matrix were of cubic structure with the average particle diameter of 1.8 to 4.8 nm. Field emission scanning electron microscopy and high resolution transmission electron microscopy images indicated that the particles were well dispersed and distributed uniformly in the matrices of alginate polymer. FT-IR spectra confirmed the presence of alginate in the nanocomposite. The crystalline nature and thermal stability of the alginate polymer was found to be influenced by the nature of the divalent metal ions used for the synthesis. The proposed method is considered to be a simple and greener approach for large scale synthesis of uniform sized nanoparticles.

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

    Directory of Open Access Journals (Sweden)

    B. Deepa

    2016-01-01

    Full Text Available 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 increase of the filler content. Incorporation of CNF also significantly reduced the swelling percentage and water solubility of alginate-based films, with the lower values found for 10 wt % in CNF. Biodegradation studies of the films in soil confirmed that the biodegradation time of alginate/CNF films greatly depends on the CNF content. The results evidence that the stronger intermolecular interaction and molecular compatibility between alginate and CNF components was at 10 wt % in CNF alginate films.

  10. Restoring forests

    DEFF Research Database (Denmark)

    Jacobs, Douglass F.; Oliet, Juan A.; Aronson, James

    2015-01-01

    of land requiring restoration implies the need for spatial prioritization of restoration efforts according to cost-benefit analyses that include ecological risks. To design resistant and resilient ecosystems that can adapt to emerging circumstances, an adaptive management approach is needed. Global change......, in particular, imparts a high degree of uncertainty about the future ecological and societal conditions of forest ecosystems to be restored, as well as their desired goods and services. We must also reconsider the suite of species incorporated into restoration with the aim of moving toward more stress resistant...... and competitive combinations in the longer term. Non-native species may serve an important role under some circumstances, e.g., to facilitate reintroduction of native species. Propagation and field establishment techniques must promote survival through seedling stress resistance and site preparation. An improved...

  11. Restoration Ecology

    Science.gov (United States)

    Jordan, William R.; Gilpin, Michael E.; Aber, John D.

    1990-08-01

    This book explores the ecological concepts and ideas involved in the practice of habitat restoration by taking a theoretical approach that will appeal to ecologists concerned with the structure and dynamics of communities. The contributors examine aspects of this new realization and its implications for both ecology and the practice of habitat restoration. What emerges is the outline of a new paradigm for ecological research and the basis for a stronger relationship between theory and practice in this area.

  12. Preparation and Biochemical Property of Penicillin G Amidase-Loaded Alginate and Alginate/Chitosan Hydrogel Beads.

    Science.gov (United States)

    Nupur, Neh; Ashish, EmptyYN Y; Debnath, Mira

    2016-01-01

    Penicillin G amidase (PGA) (EC 3.5.1.11) are enzymes that are mainly involved in the synthesis of semi-synthetic }-lactam antibiotics. Soluble PGA is costly and lacks long term operational stability. We revised most of the patents related to Penicillin G amidase (PGA) immobilization in the section "Recent Patents on Immobilized Penicillin G Amidase". The aim of this work was to study comparative biochemical property of PGA enzyme immobilized in two hydro-gel beads - Ca-alginate and alginate+chitosan hybrid and morphologically characterised by SEM. PGA immobilized in alginate+chitosan hybrid bead shows high pH and thermal stability. Km, Vmax and Effectiveness factor (1) value of free PGA were 56.19 mg/ml, 1.786 U/ml and 1, respectively. These parameters for PGA immobilized alginate beads were 64.84 mg/ml, 0.781U/ml and 0.437, respectively and for PGA immobilized alginate+chitosan hybrid beads were 87.08 mg/ml, 0.622 U/ml and 0.348, respectively. Immobilized PGA on alginate+chitosan hybrid beads gave the highest thermal stability, reusability and storage stability than alginate immobilized PGA. The entrapment of PGA on alginate+chitosan hybrid beads revealed several advantages and could be used in 6APA (6- aminopenicillanic acid) production.

  13. Comparison of some biochemical properties of artichoke polyphenol oxidase entrapped in alginate-carrageenan and alginate gels.

    Science.gov (United States)

    Yagar, Hulya; Kocaturk, Selin

    2014-08-01

    Polyphenol oxidase (PPO, EC.1.14.18.1) isolated from artichoke (Cynara scolymus) was entrapped within alginate and alginate+ carrageenan beads, and the catecholase and cresolase activities of both entrapped enzymes were determined. Some properties of these immobilized enzymes such as optimum pH and temperature, kinetic parameters (Km and Vmax), thermal, and storage stability were determined and compared to each other. The highest catecholase activity was observed in alginate gel (370 U/g bead) while the highest cresolase activity was in alginate+ carrageenan gel (90 U/g bead). For catecholase and cresolase activities, optimum pHs of alginate and alginate+ carrageenan beads were determined to be 7.0 and 4.0, respectively. Optimum temperatures for catecholase activity were determined to be 40°C for both entrapped enzymes. These values for cresolase activity were 30°C and 20°C, respectively. Immobilized artichoke PPOs greatly preserved their thermal stability which exists anyway. The catalytic efficiency value (Vmax/Km) of the alginate beads is approximately high as two-and-a-half folds of that of alginate+κ-carrageenan beads for cresolase activity. These values were very close for catecholase activity. Immobilized beads saved their both activities after 30 days of storage at 4°C.

  14. Sorbsan calcium alginate fibre dressings in footcare.

    Science.gov (United States)

    Fraser, R; Gilchrist, T

    1983-07-01

    This report outlines the successful application of Sorbsan-calcium alginate fibre dressings in footcare. This biomaterial has been found in clinical trials to have quite outstanding merit and can be used for sinus drainage and in the treatment of fissures, hypergranulation tissue, interdigital maceration, heloma molle and other lesions. Sorbsan bonds with and aids natural healing scabs and effects drainage of moist sites thus assisting in creating an environment conducive to the healing process. Similar promise has been demonstrated for this material in ongoing trials in hospitals in Sunderland where Sorbsan has been used effectively in the treatment of diabetic and trophic ulcers.

  15. Synthesis and evaluation of dual crosslinked alginate microbeads.

    Science.gov (United States)

    Somo, Sami I; Langert, Kelly; Yang, Chin-Yu; Vaicik, Marcella K; Ibarra, Veronica; Appel, Alyssa A; Akar, Banu; Cheng, Ming-Huei; Brey, Eric M

    2018-01-01

    Alginate hydrogels have been investigated for a broad variety of medical applications. The ability to assemble hydrogels at neutral pH and mild temperatures makes alginate a popular choice for the encapsulation and delivery of cells and proteins. Alginate has been studied extensively for the delivery of islets as a treatment for type 1 diabetes. However, poor stability of the encapsulation systems after implantation remains a challenge. In this paper, alginate was modified with 2-aminoethyl methacrylate hydrochloride (AEMA) to introduce groups that can be photoactivated to generate covalent bonds. This enabled formation of dual crosslinked structure upon exposure to ultraviolet light following initial ionic crosslinking into bead structures. The degree of methacrylation was varied and in vitro stability, long term swelling, and cell viability examined. At low levels of the methacrylation, the beads could be formed by first ionic crosslinks followed by exposure to ultraviolet light to generate covalent bonds. The methacrylated alginate resulted in more stable beads and cells were viable following encapsulation. Alginate microbeads, ionic (unmodified) and dual crosslinked, were implanted into a rat omentum pouch model. Implantation was performed with a local injection of 100 µl of 50 µg/ml of Lipopolysaccharide (LPS) to stimulate a robust inflammatory challenge in vivo. Implants were retrieved at 1 and 3 weeks for analysis. The unmodified alginate microbeads had all failed by week 1, whereas the dual-crosslinked alginate microbeads remained stable up through 3 weeks. The modified alginate microbeads may provide a more stable alternative to current alginate-based systems for cell encapsulation. Alginate, a naturally occurring polysaccharide, has been used for cell encapsulation to prevent graft rejection of cell transplants for people with type I diabetes. Although some success has been observed in clinical trials, the lack of reproducibility and failure to

  16. Ca2+ released from calcium alginate gels can promote inflammatory responses in vitro and in vivo

    OpenAIRE

    Chan, Gail; Mooney, David J.

    2013-01-01

    In general, alginate hydrogels are considered to be biologically inert and are commonly used for biomedical purposes that require minimum inflammation. However, Ca2+, which is commonly used to crosslink alginate, is a critical second messenger in immune cell signaling, and little has been done to understand its effect on immune cell fate when delivered as a component of alginate gels. We found that dendritic cells (DCs) encapsulated in Ca2+-crosslinked alginate (calcium alginate) secreted at ...

  17. The compartmented alginate fibres optimisation for bitumen rejuvenator encapsulation

    Directory of Open Access Journals (Sweden)

    Amir Tabaković

    2017-08-01

    Full Text Available This article presents development of a novel self-healing technology for asphalt pavements, where asphalt binder rejuvenator is encapsulated within the compartmented alginate fibres. The key objective of the study was to optimise the compartmented alginate fibre design, i.e., maximising amount of rejuvenator encapsulated within the fibre. The results demonstrate that optimum rejuvenator content in the alginate fibre is of 70:30 rejuvenator/alginate ratio. The fibres are of sufficient thermal and mechanical strength to survive harsh asphalt mixing and compaction processes. Furthermore, results illustrate that zeer open asfalt beton (ZOAB asphalt mix containing 5% of 70:30 rejuvenator/alginate ratio compartmented alginate fibres has higher strength, stiffness and better healing properties in comparison to the control asphalt mix, i.e., mix without fibres, and mix containing fibres with lower rejuvenator content. These results show that compartmented alginate fibres encapsulating bitumen rejuvenator present a promising new approach for the development of self-healing asphalt pavement systems.

  18. Controlled Electrospray Generation of Nonspherical Alginate Microparticles.

    Science.gov (United States)

    Jeyhani, Morteza; Mak, Sze Yi; Sammut, Stephen; Shum, Ho Cheung; Hwang, Dae Kun; Tsai, Scott S H

    2017-12-11

    Electrospraying is a technique used to generate microparticles in a high throughput manner. For biomedical applications, a biocompatible electrosprayed material is often desirable. Using polymers, such as alginate hydrogels, makes it possible to create biocompatible and biodegradable microparticles that can be used for cell encapsulation, to be employed as drug carriers, and for use in 3D cell culturing. Evidence in the literature suggests that the morphology of the biocompatible microparticles is relevant in controlling the dynamics of the microparticles in drug delivery and 3D cell culturing applications. Yet, most electrospray-based techniques only form spherical microparticles, and there is currently no widely adopted technique for producing nonspherical microparticles at a high throughput. Here, we demonstrate the generation of nonspherical biocompatible alginate microparticles by electrospraying, and control the shape of the microparticles by varying experimental parameters such as chemical concentration and the distance between the electrospray tip and the particle-solidification bath. Importantly, we show that these changes to the experimental setup enable the synthesis of different shaped particles, and the systematic change in parameters, such as chemical concentration, result in monotonic changes to the particle aspect ratio. We expect that these results will find utility in many biomedical applications that require biocompatible microparticles of specific shapes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Alginate based scaffolds for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Valente, J.F.A.; Valente, T.A.M. [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Faculdade de Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal); Alves, P.; Ferreira, P. [CIEPQPF, Departamento de Engenharia Quimica, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-290 Coimbra (Portugal); Silva, A. [Centro de Ciencia e Tecnologia Aeroespaciais, Universidade da Beira Interior, Covilha (Portugal); Correia, I.J., E-mail: icorreia@ubi.pt [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Faculdade de Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal)

    2012-12-01

    The design and production of scaffolds for bone tissue regeneration is yet unable to completely reproduce the native bone properties. In the present study new alginate microparticle and microfiber aggregated scaffolds were produced to be applied in this area of regenerative medicine. The scaffolds' mechanical properties were characterized by thermo mechanical assays. Their morphological characteristics were evaluated by isothermal nitrogen adsorption and scanning electron microscopy. The density of both types of scaffolds was determined by helium pycnometry and mercury intrusion porosimetry. Furthermore, scaffolds' cytotoxic profiles were evaluated in vitro by seeding human osteoblast cells in their presence. The results obtained showed that scaffolds have good mechanical and morphological properties compatible with their application as bone substitutes. Moreover, scaffold's biocompatibility was confirmed by the observation of cell adhesion and proliferation after 5 days of being seeded in their presence and by non-radioactive assays. - Highlights: Black-Right-Pointing-Pointer Design and production of scaffolds for bone tissue regeneration. Black-Right-Pointing-Pointer Microparticle and microfiber alginate scaffolds were produced through a particle aggregation technique; Black-Right-Pointing-Pointer Scaffolds' mechanically and biologically properties were characterized through in vitro studies;.

  20. Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

    Science.gov (United States)

    Johnson, Amy S.; O'Sullivan, Esther; D'Aoust, Laura N.; Omer, Abdulkadir; Bonner-Weir, Susan; Fisher, Robert J.; Weir, Gordon C.

    2011-01-01

    Improved methods have recently been developed for assessing islet viability and quantity in human islet preparations for transplantation, and these measurements have proven useful for predicting transplantation outcome. The objectives of this study were to adapt these methods for use with microencapsulated islets, to verify that they provide meaningful quantitative measurements, and to test them with two model systems: (1) barium alginate and (2) barium alginate containing a 70% (w/v) perfluorocarbon (PFC) emulsion, which presents challenges to use of these assays and is of interest in its own right as a means for reducing oxygen supply limitations to encapsulated tissue. Mitochondrial function was assessed by oxygen consumption rate measurements, and the analysis of data was modified to account for the increased solubility of oxygen in the PFC-alginate capsules. Capsules were dissolved and tissue recovered for nuclei counting to measure the number of cells. Capsule volume was determined from alginate or PFC content and used to normalize measurements. After low oxygen culture for 2 days, islets in normal alginate lost substantial viable tissue and displayed necrotic cores, whereas most of the original oxygen consumption rate was recovered with PFC alginate, and little necrosis was observed. All nuclei were recovered with normal alginate, but some nuclei from nonrespiring cells were lost with PFC alginate. Biocompatibility tests revealed toxicity at the islet periphery associated with the lipid emulsion used to provide surfactants during the emulsification process. We conclude that these new assay methods can be applied to islets encapsulated in materials as complex as PFC-alginate. Measurements made with these materials revealed that enhancement of oxygen permeability of the encapsulating material with a concentrated PFC emulsion improves survival of encapsulated islets under hypoxic conditions, but reformulation of the PFC emulsion is needed to reduce toxicity

  1. Quantitative assessment of islets of Langerhans encapsulated in alginate.

    Science.gov (United States)

    Johnson, Amy S; O'Sullivan, Esther; D'Aoust, Laura N; Omer, Abdulkadir; Bonner-Weir, Susan; Fisher, Robert J; Weir, Gordon C; Colton, Clark K

    2011-04-01

    Improved methods have recently been developed for assessing islet viability and quantity in human islet preparations for transplantation, and these measurements have proven useful for predicting transplantation outcome. The objectives of this study were to adapt these methods for use with microencapsulated islets, to verify that they provide meaningful quantitative measurements, and to test them with two model systems: (1) barium alginate and (2) barium alginate containing a 70% (w/v) perfluorocarbon (PFC) emulsion, which presents challenges to use of these assays and is of interest in its own right as a means for reducing oxygen supply limitations to encapsulated tissue. Mitochondrial function was assessed by oxygen consumption rate measurements, and the analysis of data was modified to account for the increased solubility of oxygen in the PFC-alginate capsules. Capsules were dissolved and tissue recovered for nuclei counting to measure the number of cells. Capsule volume was determined from alginate or PFC content and used to normalize measurements. After low oxygen culture for 2 days, islets in normal alginate lost substantial viable tissue and displayed necrotic cores, whereas most of the original oxygen consumption rate was recovered with PFC alginate, and little necrosis was observed. All nuclei were recovered with normal alginate, but some nuclei from nonrespiring cells were lost with PFC alginate. Biocompatibility tests revealed toxicity at the islet periphery associated with the lipid emulsion used to provide surfactants during the emulsification process. We conclude that these new assay methods can be applied to islets encapsulated in materials as complex as PFC-alginate. Measurements made with these materials revealed that enhancement of oxygen permeability of the encapsulating material with a concentrated PFC emulsion improves survival of encapsulated islets under hypoxic conditions, but reformulation of the PFC emulsion is needed to reduce toxicity.

  2. Optimization of alginate purification using polyvinylidene difluoride membrane filtration: Effects on immunogenicity and biocompatibility of three-dimensional alginate scaffolds.

    Science.gov (United States)

    Sondermeijer, Hugo P; Witkowski, Piotr; Woodland, David; Seki, Tetsunori; Aangenendt, Frank J; van der Laarse, Arnoud; Itescu, Silviu; Hardy, Mark A

    2016-10-01

    Sodium alginate is an effective biomaterial for tissue engineering applications. Non-purified alginate is contaminated with protein, lipopolysaccharide, DNA, and RNA, which could elicit adverse immunological reactions. We developed a purification protocol to generate biocompatible alginate based on (a) activated charcoal treatment, (b) use of hydrophobic membrane filtration (we used hydrophobic polyvinylidene difluoride membranes to remove organic contaminants), (c) dialysis, and finally (d) ethanol precipitation. Using this approach, we could omit pre-treatment with chloroform and significantly reduce the quantities of reagents used. Purification resulted in reduction of residual protein by 70% down to 0.315 mg/g, DNA by 62% down to 1.28 µg/g, and RNA by 61% down to less than 10 µg/g, respectively. Lipopolysaccharide levels were reduced by >90% to less than 125 EU/g. Purified alginate did not induce splenocyte proliferation in vitro. Three-dimensional scaffolds generated from purified alginate did not elicit a significant foreign body reaction, fibrotic overgrowth, or macrophage infiltration 4 weeks after implantation. This study describes a simplified and economical alginate purification method that results in alginate purity, which meets clinically useful criteria. © The Author(s) 2016.

  3. 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.

  4. Ecological restoration

    Science.gov (United States)

    Christopher D. Barton; John I. Blake; Donald W. Imm

    2005-01-01

    The long history of human settlement, agriculture, and industry at the Savannah River Site (SRS) has created extensive opportunities for ecological restoration. Two hundred years of farming, drainage, dam construction, stream channeling, fire protection, subsistence hunting and fishing, exotic animal and plant introduction, and selective timber harvesting have caused...

  5. Restorative neuroscience

    DEFF Research Database (Denmark)

    Andres, Robert H; Meyer, Morten; Ducray, Angélique D

    2008-01-01

    There is increasing interest in the search for therapeutic options for diseases and injuries of the central nervous system (CNS), for which currently no effective treatment strategies are available. Replacement of damaged cells and restoration of function can be accomplished by transplantation of...

  6. Site Restoration

    Energy Technology Data Exchange (ETDEWEB)

    Noynaert, L.; Bruggeman, A.; Cornelissen, R.; Massaut, V.; Rahier, A

    2001-04-01

    The objectives, the programme, and the achievements of the Site Restoration Department of SCK-CEN in 2000 are summarised. Main activities include the decommissioning of the BR3 PWR-reactor as well as other clean-up activities, projects on waste minimisation and activities related to the management of decommissioning projects. The department provides consultancy and services to external organisations.

  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.

  8. Preparation and microscopy examination of alginate-poly-L-lysine-alginate microcapsules.

    Science.gov (United States)

    Fu, Hong-Xing; Li, Hui; Wu, Lan-Lan; Zhao, Ying-Zheng; Xu, Yan-Yan; Zhu, Yan-Lin; Xue, Shen-Liu; Wang, Da-Wang; Liu, Cheng-Yang; Yang, Shu-Lin; Li, Xiao-Kun

    2014-11-01

    Ca-alginate-poly-l-lysine-alginate (APA-Ca) and Ba-alginate-poly-l-lysine-alginate (APA-Ba) microcapsules were prepared and their thickness and surface were examined by light microscopy and scanning electron microscopy. Specifically, light microscopy with frozen section was used to visualize and quantify the thickness of APA membrane, and monitor temporal changes in the thickness of microcapsules during a month long culture in vitro. The section graph of APA microcapsule represents the accurate measurement of layer thickness of APA-Ca with diameter 900 ± 100 and 500 ± 100 μm at 6.01 ± 1.02 and 9.54 ± 2.42 μm (p microcapsules. The microcapsule was stable during the culture for 30 days in vitro. Field emission scanning electron microscopy with freeze drying method was used to detect the surface and thickness of dried microcapsules. From the results, the outer surface of APA-Ca and APA-Ba membrane were smooth and dense, the film thickness of the APA-Ca was about 450-690 nm, while the APA-Ba was approximately 335 nm. In vivo experiment, little significant difference was seen in the change of film thickness of microcapsules in intrapertioneal site for 30 days after transplantation (p > 0.05), except that the recovery of APA-Ba was higher than the APA-Ca microcapsules. The paper showed an easy method to prepare APA-Ca and APA-Ba, and examine their thickness and surface, which could be utilized to study other types of microcapsules.

  9. Effect of alginate and alginate-cimetidine combination therapy on stimulated postprandial gastro-oesophageal reflux.

    Science.gov (United States)

    Washington, N; Denton, G

    1995-11-01

    This randomized, single-blind cross-over study compared the effectiveness of a conventional alginate reflux barrier formulation (20 mL single dose of Liquid Gaviscon; sodium alginate, sodium bicarbonate, calcium carbonate) with a 20 mL single dose of an alginate-cimetidine combination formulation (Algitec Suspension; sodium alginate, cimetidine) in the suppression of food and acid reflux into the oesophagus after a test meal in 12 healthy volunteers. Subjects were fasted overnight before the study. A pH electrode and gamma detector were accurately positioned 5 cm above the cardia. The volunteers received a 99mTc-labelled meal designed to provoke reflux and then either remained untreated, or 30 min later were given either Algitec Suspension or Liquid Gaviscon. Reflux of both food and acid into the oesophagus was measured for 3 h. There was a seven day wash-out period between each treatment. Food reflux in the control group was 22,878 +/- 14,385 counts x 10(3) and this was significantly suppressed by both Liquid Gaviscon (174 +/- 128 (s.e.) counts x 10(3); P = 0.003); however, although the reduction of food reflux to 3812 +/- 2322 counts x 10(3) observed after Algitec treatment was considerable, this did not reach statistical significance (P > 0.05) due to the large intersubject variation. Liquid Gaviscon was significantly better at reducing food reflux than Algitec (P = 0.001). Gaviscon also significantly reduced acid reflux when compared with the control group (1.08 +/- 0.73 vs 5.87 +/- 3.27% recording time oesophageal pH pH Gaviscon treatment was also not significant.

  10. Alginate-sterculia gum gel-coated oil-entrapped alginate beads for gastroretentive risperidone delivery.

    Science.gov (United States)

    Bera, Hriday; Kandukuri, Saisharan Goud; Nayak, Amit Kumar; Boddupalli, Shashank

    2015-04-20

    Novel floating-mucoadhesive oil-entrapped alginate beads coated with crossslinked alginate-sterculia gum gel membrane was developed for gastroretentive risperidone delivery. Oil-entrapped alginate beads containing risperidone as core were prepared by ionotropic gelation technique. Effects of polymer to drug ratio and oil to water ratio on drug entrapment efficiency (%) and cumulative drug release after 8h (%) were studied to optimize the core beads by a 3(2) factorial design. The optimized beads (F-O) demonstrated drug entrapment efficiency of 83.73±0.81% and cumulative drug release of 70.84±0.27% after 8h. The biopolymeric-coated optimized beads exhibited excellent buoyancy, better ex vivo mucoadhesion and slower drug release rate. The drug release profiles of risperidone-loaded uncoated and coated beads were best fitted in Korsmeyer-Peppas model with Fickian diffusion mechanism. The beads were also examined for the drug-excipients compatibility, drug crystallinity and surface morphology by FTIR, P-XRD and SEM analyses, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Elastic, superporous hydrogel hybrids of polyacrylamide and sodium alginate.

    Science.gov (United States)

    Omidian, Hossein; Rocca, Jose G; Park, Kinam

    2006-09-15

    A novel approach was developed to prepare a superporous hydrogel with superior mechanical and elastic properties. According to this method, a synthetic monomer was polymerized and crosslinked in the presence of a water-soluble alginate polymer. Later in the process, the alginate part of the synthesized hydrogel was treated with metal cations, which resulted in a hydrogel hybrid with an interpenetrating network structure. In this article, a hydrogel hybrid of acrylamide and alginate is highlighted because of its unique swelling and mechanical properties. This hydrogel hybrid shows resilience and a rubbery property in its fully water-swollen state, which not previously been reported. To help understand the underlying mechanism responsible for such unique properties with hydrogel hybrids, the ionotropic gelation of the alginate polymer was also studied in more detail.

  12. Characterization of Gelatin-Sodium Alginate Complex Coacervation System

    Science.gov (United States)

    Shinde, Ujwala A.; Nagarsenker, Mangal S.

    2009-01-01

    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. PMID:20490302

  13. Role of alginate in antibacterial finishing of textiles.

    Science.gov (United States)

    Li, Jiwei; He, Jinmei; Huang, Yudong

    2017-01-01

    Antibacterial finishing of textiles has been introduced as a necessary process for various purposes especially creating a fabric with antimicrobial activities. Currently, the textile industry continues to look for textiles antimicrobial finishing process based on sustainable biopolymers from the viewpoints of environmental friendliness, industrialization, and economic concerns. This paper reviews the role of alginate, a sustainable biopolymer, in the development of antimicrobial textiles, including both basic physicochemical properties of alginate such as preparation, chemical structure, molecular weight, solubility, viscosity, and sol-gel transformation property. Then different processing routes (e.g. nanocomposite coating, ionic cross-linking coating, and Layer-by-Layer coating) for the antibacterial finishing of textiles by using alginate are revised in some detail. The achievements in this area have increased our knowledge of alginate application in the field of textile industry and promoted the development of green textile finishing. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Enzyme-entrapping behaviors in alginate fibers and their papers

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Matsuo, R.; Ohya, T.; Yokoi, N.

    1987-01-01

    Enzyme immobilization in the form of fiber and paper was easily achieved by wet spinning of aqueous admixture of sodium alginate and enzymes into divalent metallic ion solution as a coagulating bath, followed by paper making of resultant shortly cut fibers. Entrapment yields of enzymes used, e.g., glucoamylase, cyclodextrin glucanotransferase, endo-polygalacturonase, and protease, were always higher in calcium alginate fibers and their papers than those in corresponding beads. It was found that the yields increased with an increase of the discharge rate through the spinning nozzle because the higher discharge rate could provide more highly oriented metal-chelate linear polymer molecules along the fiber axis for preventing leakage of entrapped enzymes. Divalent metallic ions affected greatly the entrapment of glucoamylase in alginate fibers, the order of which followed rougly the ionotropic series of Thiele. Entrapment of glucoamylase in bicomponent systems comprising alginate and other water-soluble polymers was also investigated. (Refs. 41).

  15. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  16. In situ growth of gold colloids within alginate films

    Energy Technology Data Exchange (ETDEWEB)

    Jaouen, Vincent; Lantiat, David; Steunou, Nathalie; Coradin, Thibaud [UPMC Univ Paris 06, CNRS, Laboratoire de Chimie de la Matiere Condensee de Paris (LCMCP), College de France, 11 place Marcellin Berthelot, F-75005 Paris (France); Brayner, Roberta, E-mail: thibaud.coradin@upmc.fr [Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS), Universite Paris Diderot, UMR-CNRS 7086, F-75205 Paris (France)

    2010-05-07

    Gold-alginate bionanocomposite films were prepared by impregnation of alginate films with HAuCl{sub 4} followed by reduction with glucose. The mannuronate over guluronate ratio (M/G) of the polymer as well as the initial polymer concentration were shown to influence the film thickness, the amount of trapped Au{sup 3+} ions, and the volume fraction of Au(0) nanoparticles but not the size of these colloids (about 4 nm). The homogeneity of the gold colloid dispersion within the alginate gels was studied by transmission electron microscopy (TEM) and confirmed by simulation of the surface plasmon resonance (SPR) spectra using the Maxwell-Garnett model. The calculated spectra also provided fruitful information about the gold colloid/alginate interface. Overall, the whole process is controlled by the balance between the M/G ratio, defining the polymer affinity for Au(III) species, and the solution viscosity, controlling the diffusion phenomena.

  17. 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.

  18. Alginate oligosaccharides: enzymatic preparation and antioxidant property evaluation.

    Science.gov (United States)

    Falkeborg, Mia; Cheong, Ling-Zhi; Gianfico, Carlo; Sztukiel, Katarzyna Magdalena; Kristensen, Kasper; Glasius, Marianne; Xu, Xuebing; Guo, Zheng

    2014-12-01

    Alginate oligosaccharides (AOs) prepared from alginate, by alginate lyase-mediated depolymerization, were structurally characterized by mass spectrometry, infrared spectrometry and thin layer chromatography. Studies of their antioxidant activities revealed that AOs were able to completely (100%) inhibit lipid oxidation in emulsions, superiorly to ascorbic acid (89% inhibition). AOs showed radical scavenging activity towards ABTṠ, hydroxyl, and superoxide radicals, which might explain their excellent antioxidant activity. The radical scavenging activity is suggested to originate mainly from the presence of the conjugated alkene acid structure formed during enzymatic depolymerization. According to the resonance hybrid theory, the parent radicals of AOs are delocalized through allylic rearrangement, and as a consequence, the reactive intermediates are stabilized. AOs were weak ferrous ion chelators. This work demonstrated that AOs obtained from a facile enzymatic treatment of abundant alginate is an excellent natural antioxidant, which may find applications in the food industry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Glucose oxidase release from calcium alginate gel capsules.

    Science.gov (United States)

    Blandino; Macías; Cantero

    2000-08-01

    Diffusion of glucose oxidase within calcium alginate gel capsules has been assayed and the experimental data fitted to a simple semi-empirical power equation, which is used to analyse the solute release from polymeric devices. It was found that an increase in the concentration of sodium alginate and calcium chloride gives rise to a reduction in the enzyme leakage. This was verified when glucose oxidase (GOD) diffusion percentages were compared in capsules with thicknesses of the same order of magnitude but obtained under different experimental conditions. So, the use of sodium alginate and calcium chloride solutions of concentrations 0.5% w/v and 2.6% w/v, respectively, lead to a diffusion percentage of 25 +/- 2. This percentage was reduced to 8 +/- 3 when sodium alginate and calcium chloride concentrations were fixed at 1% w/v and 4% w/v, respectively, even though the thicknesses of the capsules were of the same order of magnitude.

  20. Alginate hydrogels allow for bioactive and sustained release of VEGF-C and VEGF-D for lymphangiogenic therapeutic applications.

    Science.gov (United States)

    Campbell, Kevin T; Hadley, Dustin J; Kukis, David L; Silva, Eduardo A

    2017-01-01

    Lymphatic dysfunction is associated with the progression of many cardiovascular disorders due to their role in maintaining tissue fluid homeostasis. Promoting new lymphatic vessels (lymphangiogenesis) is a promising strategy to reverse these cardiovascular disorders via restoring lymphatic function. Vascular endothelial growth factor (VEGF) members VEGF-C and VEGF-D are both potent candidates for stimulating lymphangiogenesis, though maintaining spatial and temporal control of these factors represents a challenge to developing efficient therapeutic lymphangiogenic applications. Injectable alginate hydrogels have been useful for the controlled delivery of many angiogenic factors, including VEGF-A, to stimulate new blood vasculature. However, the utility of these tunable hydrogels for delivering lymphangiogenic factors has never been closely examined. Thus, the objective of this study was to utilize ionically cross-linked alginate hydrogels to deliver VEGF-C and VEGF-D for potential lymphangiogenic applications. We demonstrated that lymphatic endothelial cells (LECs) are sensitive to temporal presentation of VEGF-C and VEGF-D but with different responses between the factors. The greatest LEC mitogenic and sprouting response was observed for constant concentrations of VEGF-C and a high initial concentration that gradually decreased over time for VEGF-D. Additionally, alginate hydrogels provided sustained release of radiolabeled VEGF-C and VEGF-D. Finally, VEGF-C and VEGF-D released from these hydrogels promoted a similar number of LEC sprouts as exogenously added growth factors and new vasculature in vivo via a chick chorioallantoic membrane (CAM) assay. Overall, these findings demonstrate that alginate hydrogels can provide sustained and bioactive release of VEGF-C and VEGF-D which could have applications for therapeutic lymphangiogenesis.

  1. Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

    OpenAIRE

    Johnson, Amy S.; O'Sullivan, Esther; D'Aoust, Laura N.; Omer, Abdulkadir; Bonner-Weir, Susan; Fisher, Robert J.; Weir, Gordon C.; Colton, Clark K.

    2011-01-01

    Improved methods have recently been developed for assessing islet viability and quantity in human islet preparations for transplantation, and these measurements have proven useful for predicting transplantation outcome. The objectives of this study were to adapt these methods for use with microencapsulated islets, to verify that they provide meaningful quantitative measurements, and to test them with two model systems: (1) barium alginate and (2) barium alginate containing a 70% (w/v) perfluo...

  2. Boost for Alginate Encapsulation in Beta Cell Transplantation.

    Science.gov (United States)

    Pipeleers, Daniel; Keymeulen, Bart

    2016-05-01

    A recent study reported that encapsulation of human embryonic stem cell (hESC)-derived beta cells by a novel alginate formula protects against foreign body reactivity in immune-competent mice. Intraperitoneal implants corrected a diabetic state for at least 6 months. These observations will stimulate the development of alginate encapsulation towards novel cell therapy protocols for treating type 1 diabetes (T1DM). Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Development of a Novel Alginate-Based Pleural Sealant

    Science.gov (United States)

    2016-07-01

    official Department of the Army position, policy or decision unless so designated by other documentation. REPORT DOCUMENTATION PAGE Form Approved...purify. It was then collected and stored in -20˚C freezer . Alginate Medium Viscosity Methacrylate (Lot# UV60705FAJ) Alginate methacrylate was...dried to purify. It was then collected and stored in -20˚C freezer . Gelatin (300 bloom, type A) Methacrylate (Lot# UV60706FAJ) In a 2-neck, 1000ml

  4. Alginate/Chitosan Nanoparticles are Effective for Oral Insulin Delivery

    OpenAIRE

    B.; Sarmento; Ribeiro, A.; Veiga, F.; Sampaio, P.; Neufeld, R; Ferreira, D.

    2007-01-01

    Abstract Purpose To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats. Methods Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by con...

  5. Alginate microparticles as novel carrier for oral insulin delivery

    OpenAIRE

    Reis, Catarina Pinto; Ribeiro, António J.; Neufeld, Ronald J.; Veiga, Francisco

    2007-01-01

    Alginate microparticles produced by emulsification/internal gelation were investigated as a promising carrier for insulin delivery. The procedure involves the dispersion of alginate solution containing insulin protein, into a water immiscible phase. Gelation is triggered in situ by instantaneous release of ionic calcium from carbonate complex via gentle pH adjustment. Particle size is controlled through the emulsification parameters, yielding insulin-loaded microparticles. Particle recovery w...

  6. Nanocellulose-alginate hydrogel for cell encapsulation.

    Science.gov (United States)

    Park, Minsung; Lee, Dajung; Hyun, Jinho

    2015-02-13

    TEMPO-oxidized bacterial cellulose (TOBC)-sodium alginate (SA) composites were prepared to improve the properties of hydrogel for cell encapsulation. TOBC fibers were obtained using a TEMPO/NaBr/NaClO system at pH 10 and room temperature. The fibrillated TOBCs mixed with SA were cross-linked in the presence of Ca(2+) solution to form hydrogel composites. The compression strength and chemical stability of the TOBC/SA composites were increased compared with the SA hydrogel, which indicated that TOBC performed an important function in enhancing the structural, mechanical and chemical stability of the composites. Cells were successfully encapsulated in the TOBC/SA composites, and the viability of cells was investigated. TOBC/SA composites can be a potential candidate for cell encapsulation engineering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Ag/alginate nanofiber membrane for flexible electronic skin

    Science.gov (United States)

    Hu, Wei-Peng; Zhang, Bin; Zhang, Jun; Luo, Wei-Ling; Guo, Ya; Chen, Shao-Juan; Yun, Mao-Jin; Ramakrishna, Seeram; Long, Yun-Ze

    2017-11-01

    Flexible electronic skin has stimulated significant interest due to its widespread applications in the fields of human-machine interactivity, smart robots and health monitoring. As typical elements of electrical skin, the fabrication process of most pressure sensors combined nanomaterials and PDMS films are redundant, expensive and complicated, and their unknown biological toxicity could not be widely used in electronic skin. Hence, we report a novel, cost-effective and antibacterial approach to immobilizing silver nanoparticles into-electrospun Na-alginate nanofibers. Due to the unique role of carboxyl and hydroxyl groups in Na-alginate, the silver nanopaticles with 30 nm size in diameter were uniformly distributed inside and outside the alginate nanofibers, which obtained pressure sensor shows stable response, including an ultralow detection limited (1 pa) and high durability (>1000 cycles). Notably, the pressure sensor fabricated by these Ag/alginate nanofibers could not only follow human respiration but also accurately distinguish words like ‘Nano’ and ‘Perfect’ spoke by a tester. Interestingly, the pixelated sensor arrays based on these Ag/alginate nanofibers could monitor distribution of objects and reflect their weight by measuring the different current values. Moreover, these Ag/alginate nanofibers exhibit great antibacterial activity, implying the great potential application in artificial electronic skin.

  8. Encapsulation of fibroblasts causes accelerated alginate hydrogel degradation.

    Science.gov (United States)

    Hunt, N C; Smith, A M; Gbureck, U; Shelton, R M; Grover, L M

    2010-09-01

    Calcium-alginate hydrogel has been widely studied as a material for cell encapsulation for tissue engineering. At present, the effect that cells have on the degradation of alginate hydrogel is largely unknown. We have shown that fibroblasts encapsulated at a density of 7.5 x 10(5) cells ml(-1) in both 2% and 5% w/v alginate remain viable for at least 60 days. Rheological analysis was used to study how the mechanical properties exhibited by alginate hydrogel changed during 28 days in vitro culture. Alginate degradation was shown to occur throughout the study but was greatest within the first 7 days of culture for all samples, which correlated with a sharp release of calcium ions from the construct. Fibroblasts were shown to increase the rate of degradation during the first 7 days when compared with acellular samples in both 2% and 5% w/v gels, but after 28 days both acellular and cell-encapsulating samples retained disc-shaped morphologies and gel-like spectra. The results demonstrate that although at an early stage cells influence the mechanical properties of encapsulating alginate, over a longer period of culture, the hydrogels retain sufficient mechanical integrity to exhibit gel-like properties. This allows sustained immobilization of the cells at the desired location in vivo where they can produce extracellular matrix and growth factors to expedite the healing process. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Novel alginate based nanocomposite hydrogels with incorporated silver nanoparticles.

    Science.gov (United States)

    Obradovic, Bojana; Stojkovska, Jasmina; Jovanovic, Zeljka; Miskovic-Stankovic, Vesna

    2012-01-01

    Alginate colloid solution containing electrochemically synthesized silver nanoparticles (AgNPs) was investigated regarding the nanoparticle stabilization and possibilities for production of alginate based nanocomposite hydrogels in different forms. AgNPs were shown to continue to grow in alginate solutions for additional 3 days after the synthesis by aggregative mechanism and Ostwald ripening. Thereafter, the colloid solution remains stable for 30 days and could be used alone or in mixtures with aqueous solutions of poly(vinyl alcohol) (PVA) and poly(N-vinyl-2-pyrrolidone) (PVP) while preserving AgNPs as verified by UV-Vis spectroscopy studies. We have optimized techniques for production of Ag/alginate microbeads and Ag/alginate/PVA beads, which were shown to efficiently release AgNPs decreasing the Escherichia coli concentration in suspensions for 99.9% over 24 h. Furthermore, Ag/hydrogel discs based on alginate, PVA and PVP were produced by freezing-thawing technique allowing adjustments of hydrogel composition and mechanical properties as demonstrated in compression studies performed in a biomimetic bioreactor.

  10. 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. Copyright 2004 Elsevier B.V.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-01

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

  12. Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties

    Directory of Open Access Journals (Sweden)

    R. T. De Silva

    2017-01-01

    Full Text Available Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol (PVA polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm at a predetermined concentration (10% (w/w, is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P<0.05. In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues.

  13. Effect of alginate composition on profile release and characteristics of chitosan-alginate microparticles loaded with mangosteen extract

    Science.gov (United States)

    Mulia, Kamarza; Halimah, Nur; Krisanti, Elsa

    2017-03-01

    Preparation of mangostin-loaded chitosan-alginate microparticles, chemical and physical characterization of the particles, and mangostin release profiles, are described herein. Mangostin rich fraction was obtained from Garcinia mangostana L. pericarp by extraction followed by fractionation. Mangostin-loaded chitosan-alginate microparticles were prepared by ionic gelation method using tripolyphosphate as the linking agent and various concentration of alginate. Mangostin was effectively loaded in all microparticle formulations, resulting in ˜97% encapsulation efficiencies. The loading of mangostin and the in-vitro release profiles in simulated gastrointestinal fluids were affected by the chitosan to alginate ratios used in the preparation of the microparticles. Increased alginate concentration resulted in lowered release of mangostin from microparticles immersed in simulated gastric fluid (pH 1.2) up to two hours. Low release of mangostin in acidic fluid but high release in simulated colon fluid, indicated that the chitosan-alginate microparticles are prospective carrier for extended release of active compound in gastrointestinal system.

  14. 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

    is to inject the cells in an in situ cross-linked alginate hydrogel. METHODS: ASCs from abdominal human tissue were embedded in alginate hydrogel and alginate hydrogel modified with Arg-Gly-Asp motifs (RGD-alginate) and cultured for 1 week. Cell viability, phenotype, immunogenicity and paracrine activity were...... 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...

  15. The influence of storage duration on the setting time of type 1 alginate impression material

    Science.gov (United States)

    Rahmadina, A.; Triaminingsih, S.; Irawan, B.

    2017-08-01

    Alginate is one of the most commonly used dental impression materials; however, its setting time is subject to change depending on storage conditions and duration. This creates problems because consumer carelessness can affect alginate shelf life and quality. In the present study, the setting times of two groups of type I alginate with different expiry dates was tested. The first group consisted of 11 alginate specimens that had not yet passed the expiry date, and the second group consisted of alginates that had passed the expiry date. The alginate powder was mixed with distilled water, poured into a metal ring, and tested with a polished rod of poly-methyl methacrylate. Statistical analysis showed a significant difference (palginate that had not passed the expiry date (157 ± 3 seconds) and alginate that had passed the expiry date (144 ± 2 seconds). These findings indicate that storage duration can affect alginate setting time.

  16. Theoretical Analysis of Interaction Energy in Alginate-Capped Gold Nanoparticles Colloidal System

    Directory of Open Access Journals (Sweden)

    Foliatini Foliatini

    2014-10-01

    Full Text Available Stability of Au/alginate nanocomposite was theoretically evaluated by computing various interactions energy which contributes in the system, including attraction and repulsion interaction. The results revealed that both polymer and electrostatic charges played a significant role in the stabilization, but the steric repulsion comes from polymer chain is a more effective stabilization mechanism than the electrostatic repulsion. Higher pH yielded in stronger electrostatic repulsion but when the alginate thickness is low the resulting nanocomposite was less stable in a long time period. Interaction energies for Au/alginate nanocomposite colloidal system was up to ~60 kT for alginate thickness of 1 nm, at very short particle-particle separation distance (< 1 nm. As the alginate thickness can be controlled by adjusting the alginate concentration, it can be concluded that the high stability of Au/alginate nanocomposite can be achieved by employing an appropriate amount of alginate concentration.

  17. Kinetic and isotherm study of hexavalent chromium removal from aqueous solutions using calcium alginate beads

    Directory of Open Access Journals (Sweden)

    ghodratollah Shams Khorramabadi

    2011-08-01

    Conclusion: It can be stated that biosorption of Cr (VI onto calcium alginate occurs through a chemical mechanism. Also, according to maximum biosorption capacity, it can be stated that calcium alginate is an effective and efficient biosorbent.

  18. Ca2+ released from calcium alginate gels can promote inflammatory responses in vitro and in vivo

    Science.gov (United States)

    Chan, Gail; Mooney, David J.

    2013-01-01

    In general, alginate hydrogels are considered to be biologically inert and are commonly used for biomedical purposes that require minimum inflammation. However, Ca2+, which is commonly used to crosslink alginate, is a critical second messenger in immune cell signaling, and little has been done to understand its effect on immune cell fate when delivered as a component of alginate gels. We found that dendritic cells (DCs) encapsulated in Ca2+-crosslinked alginate (calcium alginate) secreted at least fivefold more of the inflammatory cytokine IL-1β when compared to DCs encapsulated in agarose and collagen gels, as well as DCs plated on tissue-culture polystyrene (TCPS). Plating cells on TCPS with the alginate polymer could not reproduce these results, whereas culturing DCs on TCPS with increasing concentrations of Ca2+ increased IL-1β, MHC class II and CD86 expression in a dose-dependent manner. In agreement with these findings, calcium alginate gels induced greater maturation of encapsulated DCs compared to barium alginate gels. When injected subcutaneously in mice, calcium alginate gels significantly upregulated IL-1β secretion from surrounding tissue relative to barium alginate gels, and similarly, the inflammatory effects of LPS were enhanced when it was delivered from calcium alginate gels rather than barium alginate gels. These results confirm that the Ca2+ used to crosslink alginate gels can be immunostimulatory and suggest that it is important to take into account Ca2+’s bioactive effects on all exposed cells (both immune and non-immune) when using calcium alginate gels for biomedical purposes. This work may strongly impact the way people use alginate gels in the future as well as provide insights into past work utilizing alginate gels. PMID:23938198

  19. Ca(2+) released from calcium alginate gels can promote inflammatory responses in vitro and in vivo.

    Science.gov (United States)

    Chan, Gail; Mooney, David J

    2013-12-01

    In general, alginate hydrogels are considered to be biologically inert and are commonly used for biomedical purposes that require minimum inflammation. However, Ca(2+), which is commonly used to crosslink alginate, is a critical second messenger in immune cell signaling, and little has been done to understand its effect on immune cell fate when delivered as a component of alginate gels. We found that dendritic cells (DCs) encapsulated in Ca(2+)-crosslinked alginate (calcium alginate) secreted at least fivefold more of the inflammatory cytokine IL-1β when compared to DCs encapsulated in agarose and collagen gels, as well as DCs plated on tissue-culture polystyrene (TCPS). Plating cells on TCPS with the alginate polymer could not reproduce these results, whereas culturing DCs on TCPS with increasing concentrations of Ca(2+) increased IL-1β, MHC class II and CD86 expression in a dose-dependent manner. In agreement with these findings, calcium alginate gels induced greater maturation of encapsulated DCs compared to barium alginate gels. When injected subcutaneously in mice, calcium alginate gels significantly upregulated IL-1β secretion from surrounding tissue relative to barium alginate gels, and similarly, the inflammatory effects of LPS were enhanced when it was delivered from calcium alginate gels rather than barium alginate gels. These results confirm that the Ca(2+) used to crosslink alginate gels can be immunostimulatory and suggest that it is important to take into account Ca(2+)'s bioactive effects on all exposed cells (both immune and non-immune) when using calcium alginate gels for biomedical purposes. This work may strongly impact the way people use alginate gels in the future as well as provide insights into past work utilizing alginate gels. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. In vivo degradation of alginate in the presence and in the absence of resistant starch

    NARCIS (Netherlands)

    Jonathan, M.C.; Souza Da Silva, C.; Bosch, G.; Schols, H.A.; Gruppen, H.

    2015-01-01

    This study evaluated the intestinal degradability of alginate during 74 days intake in pigs as models for humans. Diets contained pregelatinized starch, retrograded starch, alginate, or a mix of retrograded starch and alginate. Faeces were collected on day 1, 3, 7, 14, 39 and 74. Clear trends in

  1. Chondrocyte Culture in Three Dimensional Alginate Sulfate Hydrogels Promotes Proliferation While Maintaining Expression of Chondrogenic Markers

    Science.gov (United States)

    Mhanna, Rami; Kashyap, Aditya; Palazzolo, Gemma; Vallmajo-Martin, Queralt; Becher, Jana; Möller, Stephanie; Schnabelrauch, Matthias

    2014-01-01

    The loss of expression of chondrogenic markers during monolayer expansion remains a stumbling block for cell-based treatment of cartilage lesions. Here, we introduce sulfated alginate hydrogels as a cartilage biomimetic biomaterial that induces cell proliferation while maintaining the chondrogenic phenotype of encapsulated chondrocytes. Hydroxyl groups of alginate were converted to sulfates by incubation with sulfur trioxide–pyridine complex (SO3/pyridine), yielding a sulfated material cross-linkable with calcium chloride. Passage 3 bovine chondrocytes were encapsulated in alginate and alginate sulfate hydrogels for up to 35 days. Cell proliferation was five-fold higher in alginate sulfate compared with alginate (p=0.038). Blocking beta1 integrins in chondrocytes within alginate sulfate hydrogels significantly inhibited proliferation (p=0.002). Sulfated alginate increased the RhoA activity of chondrocytes compared with unmodified alginate, an increase that was blocked by β1 blocking antibodies (p=0.017). Expression and synthesis of type II collagen, type I collagen, and proteoglycan was not significantly affected by the encapsulation material evidenced by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. Alginate sulfate constructs showed an opaque appearance in culture, whereas the unmodified alginate samples remained translucent. In conclusion, alginate sulfate provides a three dimensional microenvironment that promotes both chondrocyte proliferation and maintenance of the chondrogenic phenotype and represents an important advance for chondrocyte-based cartilage repair therapies providing a material in which cell expansion can be done in situ. PMID:24320935

  2. A VERSATILE ALGINATE DROPLET GENERATOR APPLICABLE FOR MICROENCAPSULATION OF PANCREATIC-ISLETS

    NARCIS (Netherlands)

    WOLTERS, GHJ; FRITSCHY, WM; GERRITS, D; VANSCHILFAGAARDE, R

    1992-01-01

    Alginate beads for immunoisolation of pancreatic islets by microencapsulation should be small, smooth, and spherical in order to ensure that around the islets a strong alginate-polylysine-alginate capsule will be formed with optimal biocompatibility and diffusion of nutrients and hormones. However,

  3. Improved biocompatibility but limited graft survival after purification of alginate for microencapsulation of pancreatic islets

    NARCIS (Netherlands)

    DeVos, P; DeHaan, BJ; Wolters, GHJ; Strubbe, JH; VanSchilfgaarde, R; van Schilfgaarde, P.

    Graft failure of alginate-polylysine microencapsulated islets is often interpreted as the consequence of a non-specific foreign body reaction against the microcapsules, initiated by impurities present in crude alginate. The aim of the present study was to investigate if purification of the alginate

  4. Characterization of alginates from Ghanaian brown seaweeds: Sargassum spp. and Padina spp

    DEFF Research Database (Denmark)

    Rhein-Knudsen, Nanna; Ale, Marcel Tutor; Ajalloueian, Fatemeh

    2017-01-01

    , alginate samples from Laminaria digitata and Macrocystis pyrifera, used commercially for alginate extraction, contained 29% and 27% by weight of the two constituent uronic acids (M + G), respectively. Alginate extraction yields of the Ghanaian seaweeds ranged from 17 to 23% by weight of dry material...

  5. Oxidized alginate hydrogels as niche environments for corneal epithelial cells

    Science.gov (United States)

    Wright, Bernice; De Bank, Paul A; Luetchford, Kim A; Acosta, Fernando R; Connon, Che J

    2014-01-01

    Chemical and biochemical modification of hydrogels is one strategy to create physiological constructs that maintain cell function. The aim of this study was to apply oxidised alginate hydrogels as a basis for development of a biomimetic niche for limbal epithelial stem cells that may be applied to treating corneal dysfunction. The stem phenotype of bovine limbal epithelial cells (LEC) and the viability of corneal epithelial cells (CEC) were examined in oxidised alginate gels containing collagen IV over a 3-day culture period. Oxidation increased cell viability (P ≤ 0.05) and this improved further with addition of collagen IV (P ≤ 0.01). Oxidised gels presented larger internal pores (diameter: 0.2–0.8 µm) than unmodified gels (pore diameter: 0.05–0.1 µm) and were significantly less stiff (P ≤ 0.001), indicating that an increase in pore size and a decrease in stiffness contributed to improved cell viability. The diffusion of collagen IV from oxidised alginate gels was similar to that of unmodified gels suggesting that oxidation may not affect the retention of extracellular matrix proteins in alginate gels. These data demonstrate that oxidised alginate gels containing corneal extracellular matrix proteins can influence corneal epithelial cell function in a manner that may impact beneficially on corneal wound healing therapy. © 2013 The Authors. Journal of Biomedical Materials Research Part A Published byWiley Periodicals, Inc. Part A: 102A: 3393–3400, 2014. PMID:24142706

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

    Science.gov (United States)

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

    2012-01-01

    A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA pentaethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ~1.6 mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91.0 ± 1.1 and 72.6 ± 2.2%, respectively, and only 3.2 ± 0.8% water absorption after storage at room temperature in ~80% relative humidity. Moreover, Fourier transform infrared spectroscopy showed that DTPA penta-ethyl ester did not react with excipients during formation of the DTPA penta-ethyl ester-containing alginate beads. Release of prodrug from alginate beads was via anomalous transport, and its stability enhanced by encapsulation. Collectively, these data suggest that this solid dosage form may be suitable for oral administration after radionuclide contamination. PMID:23399237

  7. Encapsulation optimization of lemon balm antioxidants in calcium alginate hydrogels.

    Science.gov (United States)

    Najafi-Soulari, Samira; Shekarchizadeh, Hajar; Kadivar, Mahdi

    2016-11-01

    Calcium alginate hydrogel beads were used to encapsulate lemon balm extract. Chitosan layer was used to investigate the effect of hydrogel coating. To determine the interactions of antioxidant compounds of extract with encapsulation materials and its stability, microstructure of hydrogel beads was thoroughly monitored using scanning electron microscopy and Fourier transform infrared (FTIR). Total polyphenols content and antiradical activity of lemon balm extract were also evaluated before and after encapsulation. Three significant parameters (lemon balm extract, sodium alginate, and calcium chloride concentrations) were optimized by response surface methodology to obtain maximum encapsulation efficiency. The FTIR spectra showed no interactions between extract and polymers as there were no new band in spectra of alginate hydrogel after encapsulation of active compounds of lemon balm extract. The antioxidant activity of lemon balm extract did not change after encapsulation. Therefore, it was found that alginate is a suitable material for encapsulation of natural antioxidants. Sodium alginate solution concentration, 1.84%, lemon balm extract concentration, 0.4%, and calcium chloride concentration, 0.2% was determined to be the optimum condition to reach maximum encapsulation efficiency.

  8. Applications of Alginate-Based Bioinks in 3D Bioprinting

    Directory of Open Access Journals (Sweden)

    Eneko Axpe

    2016-11-01

    Full Text Available Three-dimensional (3D bioprinting is on the cusp of permitting the direct fabrication of artificial living tissue. Multicellular building blocks (bioinks are dispensed layer by layer and scaled for the target construct. However, only a few materials are able to fulfill the considerable requirements for suitable bioink formulation, a critical component of efficient 3D bioprinting. Alginate, a naturally occurring polysaccharide, is clearly the most commonly employed material in current bioinks. Here, we discuss the benefits and disadvantages of the use of alginate in 3D bioprinting by summarizing the most recent studies that used alginate for printing vascular tissue, bone and cartilage. In addition, other breakthroughs in the use of alginate in bioprinting are discussed, including strategies to improve its structural and degradation characteristics. In this review, we organize the available literature in order to inspire and accelerate novel alginate-based bioink formulations with enhanced properties for future applications in basic research, drug screening and regenerative medicine.

  9. Release Kinetics of Nisin from Chitosan-Alginate Complex Films.

    Science.gov (United States)

    Chandrasekar, Vaishnavi; Coupland, John N; Anantheswaran, Ramaswamy C

    2016-10-01

    Understanding the release kinetics of antimicrobials from polymer films is important in the design of effective antimicrobial packaging films. The release kinetics of nisin (30 mg/film) from chitosan-alginate polyelectric complex films prepared using various fractions of alginate (33%, 50%, and 66%) was investigated into an aqueous release medium. Films containing higher alginate fractions showed significantly lower (P nisin released from films into an aqueous system decreased significantly (P nisin from all films was found to be Fickian, and diffusion coefficients varied from 0.872 × 10-9 to 8.034 ×10-9 cm2 /s. Strong complexation was confirmed between chitosan and alginate polymers within the films using isothermal titration calorimetry and viscosity studies, which affects swelling of films and subsequent nisin release. Complexation was also confirmed between nisin and alginate, which limited the amount of free nisin available for diffusion from films. These low-swelling biopolymer complexes have potential to be used as antimicrobial packaging films with sustained nisin release characteristics. © 2016 Institute of Food Technologists®.

  10. Microwave-Assisted Synthesis of Alginate-Stabilized Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Foliatini Foliatini

    2014-12-01

    Full Text Available An efficient and rapid method for preparation of Au nanoparticles (Au-NP has been developed by direct microwave irradiation of metal precursor and alginate mixed solution in a single step. Here, alginate molecules act as both the reducing and stabilizing agents of Au-NP. The obtained nanoparticles were characterized by ultraviolet-visible (UV-Vis spectroscopy, particle size analyzer, fourier transform infrared spectroscopy, and transmission electron microscopy. The nanoparticles have a spherical form and perfectly capped with alginate when using alginate and chloro auric acid (HAuCl4 precursor in the concentration range of 0.50 to 0.75% (w/v and 0.40 mM, respectively. The use of a lower concentration of alginate and/or higher concentration of HAuCl4 caused agglomeration to occur, thereby resulting in a bigger size of Au-NP and red shifting of surface plasmon resonance (SPR peak to a higher wavelength.

  11. Nanostructured magnetic alginate composites for biomedical applications

    Directory of Open Access Journals (Sweden)

    Pedro Marins Bedê

    Full Text Available Abstract This is a study of the preparation and characterization of polymeric-magnetic nanoparticles. The nanoparticles used were magnetite (Fe3O4 and the chosen polymers were alginate and chitosan. Two types of samples were prepared: uncoated magnetic nanoparticles and magnetic nanoparticles encapsulated in polymeric matrix. The samples were analyzed by XRD, light scattering techniques, TEM, and magnetic SQUID. The XRD patterns identified magnetite (Fe3O4 as the only crystalline phase. TEM analyses showed particle sizes between 10 and 20nm for magnetite, and 15 and 30nm for the encapsulated magnetite. The values of magnetization ranged from 75 to 100emu/g for magnetite nanoparticles, and 8 to 12emu/g for coated with chitosan, at different temperatures of 20K and 300K. The saturation of both samples was in the range of 49 to 50KOe. Variations of results between the two kinds of samples were attributed to the encapsulation of magnetic nanoparticles by the polymers.

  12. Site Restoration

    Energy Technology Data Exchange (ETDEWEB)

    Noynaert, L.; Bruggeman, A.; Cornelissen, R.; Massaut, V.; Rahier, A

    2002-04-01

    The objectives, the programme, and the achievements of SCK-CEN's Site Restoration Department for 2001 are described. Main activities include the decommissioning of the BR3 PWR-reactor as well as other clean-up activities, projects on waste minimisation and the management of spent fuel and the flow of dismantled materials and the recycling of materials from decommissioning activities based on the smelting of metallic materials in specialised foundries. The department provides consultancy and services to external organisations and performs R and D on new techniques including processes for the treatment of various waste components including the reprocessing of spent fuel, the treatment of tritium, the treatment of liquid alkali metals into cabonates through oxidation, the treatment of radioactive organic waste and the reconditioning of bituminised waste products.

  13. Alginate-Dependent Gene Expression Mechanism in Sphingomonas sp. Strain A1

    Science.gov (United States)

    Hayashi, Chie; Takase, Ryuichi; Momma, Keiko; Maruyama, Yukie; Murata, Kousaku

    2014-01-01

    Sphingomonas sp. strain A1, a Gram-negative bacterium, directly incorporates alginate polysaccharide into the cytoplasm through a periplasmic alginate-binding protein-dependent ATP-binding cassette transporter. The polysaccharide is degraded to monosaccharides via the formation of oligosaccharides by endo- and exotype alginate lyases. The strain A1 proteins for alginate uptake and degradation are encoded in both strands of a genetic cluster in the bacterial genome and inducibly expressed in the presence of alginate. Here we show the function of the alginate-dependent transcription factor AlgO and its mode of action on the genetic cluster and alginate oligosaccharides. A putative gene within the genetic cluster seems to encode a transcription factor-like protein (AlgO). Mutant strain A1 (ΔAlgO mutant) cells with a disrupted algO gene constitutively produced alginate-related proteins. DNA microarray analysis indicated that wild-type cells inducibly transcribed the genetic cluster only in the presence of alginate, while ΔAlgO mutant cells constitutively expressed the genetic cluster. A gel mobility shift assay showed that AlgO binds to the specific intergenic region between algO and algS (algO-algS). Binding of AlgO to the algO-algS intergenic region diminished with increasing alginate oligosaccharides. These results demonstrated a novel alginate-dependent gene expression mechanism. In the absence of alginate, AlgO binds to the algO-algS intergenic region and represses the expression of both strands of the genetic cluster, while in the presence of alginate, AlgO dissociates from the algO-algS intergenic region via binding to alginate oligosaccharides produced through the lyase reaction and subsequently initiates transcription of the genetic cluster. This is the first report on the mechanism by which alginate regulates the expression of the gene cluster. PMID:24816607

  14. Bioactive apatite incorporated alginate microspheres with sustained drug-delivery for bone regeneration application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haibin; Jiang, Fei; Ye, Song; Wu, Yingying; Zhu, Kaiping; Wang, Deping, E-mail: wdpshk@tongji.edu.cn

    2016-05-01

    The strontium-substituted hydroxyapatite microspheres (SrHA) incorporated alginate composite microspheres (SrHA/Alginate) were prepared via adding SrHA/alginate suspension dropwise into calcium chloride solution, in which the gel beads were formed by means of crosslinking reaction. The structure, morphology and in vitro bioactivity of the composite microspheres were studied by using XRD, SEM and EDS methods. The biological behaviors were characterized and analyzed through inductively coupled plasma optical emission spectroscopy (ICP-OES), CCK-8, confocal laser microscope and ALP activity evaluations. The experimental results indicated that the synthetic SrHA/Alginate showed similar morphology to the well-known alginate microspheres (Alginate) and both of them possessed a great in vitro bioactivity. Compared with the control Alginate, the SrHA/Alginate enhanced MC3T3-E1 cell proliferation and ALP activity by releasing osteoinductive and osteogenic Sr ions. Furthermore, vancomycin was used as a model drug to investigate the drug release behaviors of the SrHA/Alginate, Alginate and SrHA. The results suggested that the SrHA/Alginate had a highest drug-loading efficiency and best controlled drug release properties. Additionally, the SrHA/Alginate was demonstrated to be pH-sensitive as well. The increase of the pH value in phosphate buffer solution (PBS) accelerated the vancomycin release. Accordingly, the multifunctional SrHA/Alginate can be applied in the field of bioactive drug carriers and bone filling materials. - Highlights: • The pH-sensitive composite alginate beads incorporating Sr-doped HA microspheres (SrHA) have been prepared. • The incorporation of the SrHA enhanced the drug loading and release properties of the alginate microspheres. • The composite microspheres showed excellent osteogenic effect by releasing osteogenic Sr ions.

  15. Characterization of methacrylated alginate and acrylic monomers as versatile SAPs.

    Science.gov (United States)

    Mignon, Arn; Vermeulen, Jolien; Graulus, Geert-Jan; Martins, José; Dubruel, Peter; De Belie, Nele; Van Vlierberghe, Sandra

    2017-07-15

    Superabsorbent polymers (SAPs) based on polysaccharides, especially alginate, could offer a valuable solution in a plethora of applications going from drug delivery to self-healing concrete. This has already been proven with both calcium alginate and methacrylated alginate combined with acrylic acid. In this manuscript, the effect of varying the degree of methacrylation and use of a combination of acrylic acid and acrylamide is investigated to explore the effects on the relevant SAP characteristics. The materials showed high gel fractions and a strong swelling capacity up to 630gwater/gSAP, especially for superabsorbent polymers with a low degree of substitution. The SAPs also showed only a limited hydrolysis in aqueous and cement filtrate solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Nanocrystalline cellulose (NCC) reinforced alginate based biodegradable nanocomposite film.

    Science.gov (United States)

    Huq, Tanzina; Salmieri, Stephane; Khan, Avik; Khan, Ruhul A; Le Tien, Canh; Riedl, Bernard; Fraschini, Carole; Bouchard, Jean; Uribe-Calderon, Jorge; Kamal, Musa R; Lacroix, Monique

    2012-11-06

    Nanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control. Incorporation of NCC also significantly improved water vapor permeability (WVP) of the nanocomposite showing a 31% decrease due to 5 wt% NCC loading. Molecular interactions between alginate and NCC were supported by Fourier Transform Infrared Spectroscopy. The X-ray diffraction studies also confirmed the appearance of crystalline peaks due to the presence of NCC inside the films. Thermal stability of alginate-based nanocomposite films was improved after incorporation of NCC. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Evaluation of Three-Dimensional Porous Iron-Cross-Linked Alginate as a Scaffold for Cell Culture

    OpenAIRE

    Machida-Sano, Ikuko; Ogawa, Sakito; Hirakawa, Makoto; Namiki, Hideo

    2014-01-01

    We investigated the efficacy of three-dimensional porous ferric-ion-cross-linked alginate (Fe-alginate) gels as cell scaffolds, in comparison with calcium-ion-cross-linked alginate (Ca-alginate) gels. In a previous study, we had demonstrated that two-dimensional Fe-alginate film was an efficient material for use as a scaffold, allowing good cell adhesion and proliferation, unlike Ca-alginate film. In the present study, we fabricated three-dimensional porous Fe- and Ca-alginate gels by freeze-...

  19. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes.

    Science.gov (United States)

    Kim, Han-Sem; Song, Minsoo; Lee, Eun-Jung; Shin, Ueon Sang

    2015-06-01

    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 (1)H, and (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 (2w/v%) with NaAlg solution (2w/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 3-40min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤6.7kPa for compressive strength at break and about 8.4kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100-800μm. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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.

  1. Alginate Biosynthesis in Azotobacter vinelandii: Overview of Molecular Mechanisms in Connection with the Oxygen Availability

    Directory of Open Access Journals (Sweden)

    Ivette Pacheco-Leyva

    2016-01-01

    Full Text Available The Gram-negative bacterium Azotobacter vinelandii can synthetize the biopolymer alginate that has material properties appropriate for plenty of applications in industry as well as in medicine. In order to settle the foundation for improving alginate production without compromising its quality, a better understanding of the polymer biosynthesis and the mechanism of regulation during fermentation processes is necessary. This knowledge is crucial for the development of novel production strategies. Here, we highlight the key aspects of alginate biosynthesis that can lead to producing an alginate with specific material properties with particular focus on the role of oxygen availability linked with the molecular mechanisms involved in the alginate production.

  2. Effect of alginate in patients with GERD hiatal hernia matters.

    Science.gov (United States)

    Vardar, R; Keskin, M; Valitova, E; Bayrakci, B; Yildirim, E; Bor, S

    2017-10-01

    Alginate-based formulations are frequently used as add-on proton pump inhibitor (PPI) therapy to help control of heartburn and regurgitation. There are limited data regarding the mechanisms and effects of alginate-based formulations. We aimed to evaluate the effects of the sodium alginate intake and its likely temporal relations on intraesophageal reflux events by MII-pH in patients with and without hiatal hernia (HH). Fifty GERD patients (18 with HH, 32 without HH) with heartburn or regurgitation once a week or more common were included. After combined multichannel intraluminal impedance and pH-metry (MII-pH) had been performed, all patients were asked to eat the same standard meal (double cheeseburger, 1 banana, 100 g regular yoghurt, and 200 mL water with total energy value of 744 kcal: 37.6% of carbohydrates, 21.2% of proteins, and 41.2% of lipids) during two consecutive days. On separate random two consecutive days, all patients took 10 mL of sodium alginate (GA; Gaviscon Advance; Reckitt Benckiser Healthcare, Hull, UK) or 10 mL of water, 30 minutes after the refluxogenic meal. After eating refluxogenic meal, patients were examined ½ hour for basal conditions, 1 hour in upright, and 1 hour in supine positions. Alginate significantly decreased acid reflux after intake at the first hour in comparison to water in patients with HH (6.1 vs. 13.7, P = 0.004) and without HH (3.5 vs. 5.5, P = 0.001). Weakly acid reflux were increased at the first hour in patients with HH (3.4 vs. 1.3, P = 0.019) and without HH (1.7 vs. 5, P = 0.02) compared to water. There was no distinctive effect of alginate on the height of proximal migration of reflux events in patients with HH and without HH. Alginate decreases acid reflux events within a limited time period, especially at the first hour both in patients with and without HH. Alginate has no effect on the height of reflux events along the esophagus both in patients with and without HH. © The Authors 2017. Published by Oxford

  3. The effect of alginate lyase on the gentamicin resistance of Pseudomonas aeruginosa in mucoid biofilms.

    Science.gov (United States)

    Germoni, L A P; Bremer, P J; Lamont, I L

    2016-07-01

    Pseudomonas aeruginosa can secrete large amounts of alginate during chronic infections and this has been associated with high resistance to antibiotics. The major aim of this study was to investigate whether degradation of extracellular alginate by alginate lyase would increase the sensitivity of Ps. aeruginosa to gentamicin, an aminoglycoside antibiotic. Degradation of alginate from Ps. aeruginosa was monitored using a spectrometric assay. Alginate lyase depolymerized alginate, but calcium and zinc cations at concentrations found in the cystic fibrosis lung reduced enzyme activity. Biofilms formed on agar were partially degraded by alginate lyase, but staining with crystal violet showed that the biomass of biofilms grown in liquid was not significantly affected by the enzyme. Viability testing showed that the sensitivity to gentamicin of biofilm bacteria and of bacteria released from biofilms was unaffected by alginate lyase. Our results show that at least under the conditions used here alginate lyase does not affect gentamicin resistance of Ps. aeruginosa. Our study indicates that alginate does not contribute to resistance to gentamicin and so does not provide support for the concept of treating patients with alginate lyase in order to increase the antibiotic sensitivity of Ps. aeruginosa. © 2016 The Society for Applied Microbiology.

  4. Characterization and properties of sodium alginate from brown algae used as an ecofriendly superabsorbent

    Science.gov (United States)

    Helmiyati; Aprilliza, M.

    2017-04-01

    Sodium alginate obtained from the extraction of brown algae is used as the backbone for the synthesis of superabsorbent nanocomposite copolymerization. The first stage of extraction is the demineralization process using 0.1 M HCl solution and then 2% Na2CO3 solution for 2 hours at 60°C. The rendement of sodium alginate obtained was 44.32% with molecular weight of 40680 g/mol with measurement of the intrinsic viscosity. FTIR spectra of sodium alginate showed mannuronic acid functional group at wavenumber 884 cm-1 and the uronic acid at wavenumber 939 cm-1, OH functional group at wavenumber 3200-3400 cm-1, and CH2 stretching at wavenumber 2928 cm-1. The diffraction pattern of isolated sodium alginate has specific 2θ at 13.068 and 21.096, amorphous intensity found specific 2θ at 18.058, and the obtained crystallinity degree of the sodium alginate is equal to 29.292% from the XRD analysis. The morphological analysis by SEM shows fibrils of isolated sodium alginate. The success isolation of sodium alginate from brown algae is supported by DSC which shows the decomposition temperature of pure sodium alginate and isolated alginate have close values, namely 251.12°C for pure sodium alginate and 229.90°C for isolated sodium alginate.

  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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Controlled release of metronidazole from composite poly-ε-caprolactone/alginate (PCL/alginate) rings for dental implants.

    Science.gov (United States)

    Lan, Shih-Feng; Kehinde, Timilehin; Zhang, Xiangming; Khajotia, Sharukh; Schmidtke, David W; Starly, Binil

    2013-06-01

    Dental implants provide support for dental crowns and bridges by serving as abutments for the replacement of missing teeth. To prevent bacterial accumulation and growth at the site of implantation, solutions such as systemic antibiotics and localized delivery of bactericidal agents are often employed. The objective of this study was to demonstrate a novel method of controlled localized delivery of antibacterial agents to an implant site using a biodegradable custom fabricated ring. The study involved incorporating a model antibacterial agent (metronidazole) into custom designed poly-ε-caprolactone/alginate (PCL/alginate) composite rings to produce the intended controlled release profile. The rings can be designed to fit around the body of any root form dental implants of various diameters, shapes and sizes. In vitro release studies indicate that pure (100%) alginate rings exhibited an expected burst release of metronidazole in the first few hours, whereas Alginate/PCL composite rings produced a medium burst release followed by a sustained release for a period greater than 4 weeks. By varying the PCL/alginate weight ratios, we have shown that we can control the amount of antibacterial agents released to provide the minimal inhibitory concentration (MIC) needed for adequate protection. The fabricated composite rings have achieved a 50% antibacterial agent release profile over the first 48 h and the remaining amount slowly released over the remainder of the study period. The PCL/alginate agent release characteristic fits the Ritger-Peppas model indicating a diffusion-based mechanism during the 30-day study period. The developed system demonstrates a controllable drug release profile and the potential for the ring to inhibit bacterial biofilm growth for the prevention of diseases such as peri-implantitis resulting from bacterial infection at the implant site. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. 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.

  8. Alginate microbeads are coagulation compatible, while alginate microcapsules activate coagulation secondary to complement or directly through FXII.

    Science.gov (United States)

    Gravastrand, Caroline; Hamad, Shamal; Fure, Hilde; Steinkjer, Bjørg; Ryan, Liv; Oberholzer, Josè; Lambris, John D; Lacík, Igor; Mollnes, Tom Eirik; Espevik, Terje; Brekke, Ole-Lars; Rokstad, Anne Mari

    2017-08-01

    Alginate microspheres are presently under evaluation for future cell-based therapy. Their ability to induce harmful host reactions needs to be identified for developing the most suitable devices and efficient prevention strategies. We used a lepirudin based human whole blood model to investigate the coagulation potentials of alginate-based microspheres: alginate microbeads (Ca/Ba Beads), alginate poly-l-lysine microcapsules (APA and AP microcapsules) and sodium alginate-sodium cellulose sulfate-poly(methylene-co-cyanoguanidine) microcapsules (PMCG microcapsules). Coagulation activation measured by prothrombin fragments 1+2 (PTF1.2) was rapidly and markedly induced by the PMCG microcapsules, delayed and lower induced by the APA and AP microcapsules, and not induced by the Ca/Ba Beads. Monocytes tissue factor (TF) expression was similarly activated by the microcapsules, whereas not by the Ca/Ba Beads. PMCG microcapsules-induced PTF1.2 was abolished by FXII inhibition (corn trypsin inhibitor), thus pointing to activation through the contact pathway. PTF1.2 induced by the AP and APA microcapsules was inhibited by anti-TF antibody, pointing to a TF driven coagulation. The TF induced coagulation was inhibited by the complement inhibitors compstatin (C3 inhibition) and eculizumab (C5 inhibition), revealing a complement-coagulation cross-talk. This is the first study on the coagulation potentials of alginate microspheres, and identifies differences in activation potential, pathways and possible intervention points. Alginate microcapsules are prospective candidate materials for cell encapsulation therapy. The material surface must be free of host cell adhesion to ensure free diffusion of nutrition and oxygen to the encapsulated cells. Coagulation activation is one gateway to cellular overgrowth through deposition of fibrin. Herein we used a physiologically relevant whole blood model to investigate the coagulation potential of alginate microcapsules and microbeads. The

  9. Restoration of Lowland Streams

    DEFF Research Database (Denmark)

    Osborne, L. L.; Bayley, P. B.; Higler, L. W. G.

    1993-01-01

    Sammenskrivning af resultater fra symposium: Lowland Streams Restoration Workshop, Lund, Sweden, August 1991......Sammenskrivning af resultater fra symposium: Lowland Streams Restoration Workshop, Lund, Sweden, August 1991...

  10. Immobilization of a Plant Lipase from Pachira aquatica in Alginate and Alginate/PVA Beads

    Directory of Open Access Journals (Sweden)

    Bárbara M. Bonine

    2014-01-01

    Full Text Available This study reports the immobilization of a new lipase isolated from oleaginous seeds of Pachira aquatica, using beads of calcium alginate (Alg and poly(vinyl alcohol (PVA. We evaluated the morphology, number of cycles of reuse, optimum temperature, and temperature stability of both immobilization methods compared to the free enzyme. The immobilized enzymes were more stable than the free enzyme, keeping 60% of the original activity after 4 h at 50°C. The immobilized lipase was reused several times, with activity decreasing to approximately 50% after 5 cycles. Both the free and immobilized enzymes were found to be optimally active between 30 and 40°C.

  11. In vitro propagation of Acacia hybrid through alginate-encapsulated ...

    African Journals Online (AJOL)

    Seed collected from Acacia hybrid trees yields highly variable and poorly performing offspring and are not commonly used in regeneration. The present study described the incapsulation of Acacia hybrid shoots and axillary buds in the calcium alginate gel. The aim of the study was to evaluate the germination of the buds in ...

  12. 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...

  13. Continuous removal and recovery of lead by alginate beads, free ...

    African Journals Online (AJOL)

    This study examines the possibility of using Chlorella vulgaris cells in repeated lead adsorption/desorption cycles. Alginate beads and immobilized with algal cells were more effective and suitable than free cells. Consistently high lead removal (>90%) and recovery (about 100%) were achieved. Lead adsorption was mainly ...

  14. Development of Alginate/Chitosan Microparticles for Dust Mite Allerge

    African Journals Online (AJOL)

    The highest allergen content (0.30 ± 0.07 mg/g) was obtained with 2.5 % initial allergen loading in chitosan- triphosphate (CS-TPP) microparticles. Sustained allergen release (approx. 50 % over 24 h) was observed from alginate-coated chitosan microparticles. Allergen incorporation method and initial drug-loading could ...

  15. the potential of alginic acid and polygal for soil stabilization

    African Journals Online (AJOL)

    user

    1985-09-01

    Sep 1, 1985 ... and the changes in the engineering properties of the soils with additives admixed are discussed. The possibility of using alginic acid and polygal as ..... Soil Mechanics. McGraw Hill Univ. Series In Civ. Engineering, 1978. 18. Schofield, A.N. and Wroth, C.P.. Critical State Soil Mechanics. McGraw Hill Bk. Co.

  16. Alginate Sulfate-Nanocellulose Bioinks for Cartilage Bioprinting Applications.

    Science.gov (United States)

    Müller, Michael; Öztürk, Ece; Arlov, Øystein; Gatenholm, Paul; Zenobi-Wong, Marcy

    2017-01-01

    One of the challenges of bioprinting is to identify bioinks which support cell growth, tissue maturation, and ultimately the formation of functional grafts for use in regenerative medicine. The influence of this new biofabrication technology on biology of living cells, however, is still being evaluated. Recently we have identified a mitogenic hydrogel system based on alginate sulfate which potently supports chondrocyte phenotype, but is not printable due to its rheological properties (no yield point). To convert alginate sulfate to a printable bioink, it was combined with nanocellulose, which has been shown to possess very good printability. The alginate sulfate/nanocellulose ink showed good printing properties and the non-printed bioink material promoted cell spreading, proliferation, and collagen II synthesis by the encapsulated cells. When the bioink was printed, the biological performance of the cells was highly dependent on the nozzle geometry. Cell spreading properties were maintained with the lowest extrusion pressure and shear stress. However, extruding the alginate sulfate/nanocellulose bioink and chondrocytes significantly compromised cell proliferation, particularly when using small diameter nozzles and valves.

  17. 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.

  18. Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system.

    Science.gov (United States)

    Katuwavila, Nuwanthi P; Perera, A D L C; Dahanayake, Damayanthi; Karunaratne, V; Amaratunga, Gehan A J; Karunaratne, D Nedra

    2016-11-20

    A novel, efficient delivery system for iron (Fe2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30nm and with a negative zeta potential (-38mV). The in vitro release studies showed a prolonged release profile for 96h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2.The initial burst release upto 8h followed zero order kinetics at all three pH values. All the release profiles beyond 8h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Transformation of brushite to hydroxyapatite and effects of alginate additives

    Science.gov (United States)

    Ucar, Seniz; Bjørnøy, Sindre H.; Bassett, David C.; Strand, Berit L.; Sikorski, Pawel; Andreassen, Jens-Petter

    2017-06-01

    Phase transformations are important processes during mineral formation in both in vivo and in vitro model systems and macromolecules are influential in regulating the mineralization processes. Calcium phosphate mineralized alginate hydrogels are potential candidates for hard tissue engineering applications and transformation of the resorbable calcium phosphate phases to apatitic bone mineral in vivo enhances the success of these composite materials. Here, the transformation of brushite to hydroxyapatite (HA) and the effects of alginate additives on this process are studied by the investigation of supersaturation profiles with HA-seeded and unseeded experiments. This experimental design allows for detailed kinetic interpretation of the transformation reactions and deduction of information on the nucleation stage of HA by evaluating the results of seeded and unseeded experiments together. In the experimental conditions of this work, transformation was controlled by HA growth until the point of near complete brushite dissolution where the growth and dissolution rates were balanced. The presence of alginate additives at low concentration were not highly influential on transformation rates during the growth dominated region but their retardant effect became more pronounced as the dissolution and growth rates reached an equilibrium where both reactions were effective on transformation kinetics. Decoupling of seeded and unseeded transformation experiments suggested that alginate additives retard HA nucleation and this was most evident in the presence of G-block oligomers.

  20. Alginate-Chitosan Particulate System for Sustained Release of ...

    African Journals Online (AJOL)

    Erah

    Available online at http://www.tjpr.org. Research Article ... diffraction (XRD), and atomic absorption spectroscopy (AAS) were also applied to investigate the physicochemical characteristics of the drug in ... Both calcium alginate beads and the beads treated with chitosan failed to release the drug at pH 1.2 over the period of ...

  1. Comparison Of The Dimensional Stability Of Alginate Impressions ...

    African Journals Online (AJOL)

    Methodology: Alginate impressions of a master model of truncated metal cones were made and disinfected with 1% sodium hypochlorite constituted from 3.5% household bleach using the spray and immersion technique for 10;20 and 30 minutes. Impressions were cast in dental stone and the linear dimensional differences ...

  2. 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.

  3. 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.

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

    Czech Academy of Sciences Publication Activity Database

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

    2003-01-01

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

  5. Removal of Uranium from Aqueous Solution by Alginate Beads

    Directory of Open Access Journals (Sweden)

    Jing Yu

    2017-04-01

    Full Text Available The adsorption of uranium (VI by calcium alginate beads was examined by batch experiments. The effects of environmental conditions on U (VI adsorption were studied, including contact time, pH, initial concentration of U (VI, and temperature. The alginate beads were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Fourier transform infrared spectra indicated that hydroxyl and alkoxy groups are present at the surface of the beads. The experimental results showed that the adsorption of U (VI by alginate beads was strongly dependent on pH, the adsorption increased at pH 3∼7, then decreased at pH 7∼9. The adsorption reached equilibrium within 2 minutes. The adsorption kinetics of U (VI onto alginate beads can be described by a pseudo first-order kinetic model. The adsorption isotherm can be described by the Redlich-Peterson model, and the maximum adsorption capacity was 237.15 mg/g. The sorption process is spontaneous and has an exothermic reaction.

  6. Adsorption studies of phosphate ions on alginate-calcium carbonate ...

    African Journals Online (AJOL)

    Alginate-calcium carbonate composite beads was prepared by the sol-gel method and characterized by Fourier transform infra-red spectroscopy (FT-IR) and scanning electron microscope (SEM) instruments. Adsorption potential of phosphate ions have been studied on laboratory scale. The effects of contact time, adsorbent ...

  7. Binding and Leakage of Barium in Alginate Microbeads

    Science.gov (United States)

    Mørch, Yrr A.; Qi, Meirigeng; Gundersen, Per Ole M.; Formo, Kjetil; Lacik, Igor; Skjåk-Bræk, Gudmund; Oberholzer, Jose; Strand, Berit L.

    2013-01-01

    Microbeads of alginate cross-linked with Ca2+ and/or Ba2+ are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared to high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. In order to reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. PMID:22700168

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

    Science.gov (United States)

    Liu, Mingxian; Dai, Libing; Shi, Huizhe; Xiong, Sheng; Zhou, Changren

    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 100-200μm 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Microfluidic one-step fabrication of radiopaque alginate microgels with in situ synthesized barium sulfate nanoparticles.

    Science.gov (United States)

    Wang, Qin; Zhang, Di; Xu, Huibi; Yang, Xiangliang; Shen, Amy Q; Yang, Yajiang

    2012-11-21

    In this work, we report a new strategy to fabricate monodispersed radiopaque alginate (Ba-alginate) microgels by a one-step microfluidic method. Alginate droplets containing sulfate ions are first formed by a flow focusing microfluidic setup. These alginate droplets are subsequently solidified by barium ions in a collection bath. During the solidification process, excessive barium ions in the collection bath also react with sulfate ions in the alginate droplet, resulting in barium sulfate (BaSO(4)) nanoparticles in situ synthesized (acting as radiopaque imaging agents) within the Ba-alginate microgels. Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) illustrate that 800 nm BaSO(4) nanoparticles are uniformly distributed inside the 30 μm Ba-alginate microgels, with 62 wt% of elemental barium (Ba). In addition, X-ray diffraction (XRD) measurements indicate that the BaSO(4) nanoparticles consist of 10 nm in situ synthesized BaSO(4) crystallites. The alginate microgels act as a soft and porous template to prevent the precipitation and aggregation of BaSO(4) nanoparticles. The Ba-alginate microgels are also visible under X-ray radiation. The facile route to fabricate alginate microgels as radiopaque embolic materials is of particular importance for endovascular embolization and localized diagnostic imaging applications. Similar approaches can also be adopted for synthesizing other inorganic nanoparticles in microgels.

  10. Survey of Bacterial and Fungal Contaminations in Iranian Alginate, Foreign Alginate and Speedex Used for Impression in Dentistry

    Directory of Open Access Journals (Sweden)

    Abbas Falah Tafti

    2012-02-01

    Full Text Available Background and Aims: Since impression materials usually contact with saliva, blood, and oral soft tissues, their microbial contamination are harmful in immunocompromised patients. The aim of the present study was to determine the bacterial and fungal contamination in common impression materials. Materials and Methods: In current lab trial study, 5 different samples from each 4 impression materials were homogenized in 1 ml Tween 80 and then 100µl of each sample were cultured onto blood agar, EMB, or sabouraud dextrose agar. Bacterial and fungal cultures were incubated at 37º C and 30º C, respectively. The isolated bacterial and fungal colonies were enumerated and identified using specific diagnostic media and tests. Data were analyzed using Kruskal-Wallis test. Results: Totally 75% of samples had one or several bacterial contaminations. Iranian alginate and Speedex (putty were the most contaminated samples. On the other hand, Speedex (light body and foreign alginate showed lower contamination. Species of Micrococcus, Staphylococcus, Bacilluses, Corynebacteria, gram negative Citrobacter, Actinomycetes and Neisseria were isolated from the analyzed impression materials. Aspergillus, Penicillium, Alternaria, Cladosporium and Sepdonium were the fungi isolated from impression materials. Statistical significant difference was shown between bacterial contamination of Iranian and foreign alginates (P=0.001. There was no statistical significant differences between the bacterial and fungal isolated colonies (CFU/gr of 4 tested impression materials (P=0.21. Conclusion: Several opportunistic bacteria and fungi were isolated from impression materials especially from Iranian alginate and Speedex putty which indicated their contamination.

  11. Comparative study on the in vitro effects of Pseudomonas aeruginosa and seaweed alginates on human gut microbiota.

    Directory of Open Access Journals (Sweden)

    Shaofeng Bai

    Full Text Available Alginates pertain to organic polysaccharides that have been extensively used in food- and medicine-related industries. The present study obtained alginates from an alginate overproducing Pseudomonas aeruginosa PAO1 mutant by screening transposon mutagenesis libraries. The interaction between bacterial and seaweed alginates and gut microbiota were further studied by using an in vitro batch fermentation system. Thin-layer chromatography (TLC analysis indicated that both bacterial and seaweed alginates can be completely degraded by fecal bacteria isolated from study volunteers, indicating that a minor structural difference between bacterial and seaweed alginates (O-acetylation and lack of G-G blocks didn't affect the digestion of alginates by human microbiota. Although, the digestion of bacterial and seaweed alginates was attributed to different Bacteroides xylanisolvens strains, they harbored similar alginate lyase genes. Genus Bacteroides with alginate-degrading capability were enriched in growth medium containing bacterial or seaweed alginates after in vitro fermentation. Short-chain fatty acid (SCFA production in both bacterial and seaweed alginates was also comparable, but was significantly higher than the same medium using starch. In summary, the present study has isolated an alginate-overproducing P. aeruginosa mutant strain. Both seaweed and bacterial alginates were degraded by human gut microbiota, and their regulatory function on gut microbiota was similar.

  12. Different responses in the expression of alginases, alginate polymerase and acetylation genes during alginate production by Azotobacter vinelandii under oxygen-controlled conditions.

    Science.gov (United States)

    Díaz-Barrera, Alvaro; Maturana, Nataly; Pacheco-Leyva, Ivette; Martínez, Irene; Altamirano, Claudia

    2017-07-01

    Alginate production and gene expression of genes involved in alginate biosynthesis were evaluated in continuous cultures under dissolved oxygen tension (DOT) controlled conditions. Chemostat at 8% DOT showed an increase in the specific oxygen uptake rate [Formula: see text] from 10.9 to 45.3 mmol g -1  h -1 by changes in the dilution rate (D) from 0.06 to 0.10 h -1 , whereas under 1% DOT the [Formula: see text] was not affected. Alginate molecular weight was not affected by DOT. However, chemostat at 1% DOT showed a downregulation up to 20-fold in genes encoding both the alginate polymerase (alg8, alg44), alginate acetylases (algV, algI) and alginate lyase AlgL. alyA1 and algE7 lyases gene expressions presented an opposite behavior by changing the DOT, suggesting that A. vinelandii can use specific depolymerases depending on the oxygen level. Overall, the DOT level have a differential effect on genes involved in alginate synthesis, thus a gene expression equilibrium determines the production of alginates of similar molecular weight under DOT controlled.

  13. Cell-matrix Interactions of Factor IX (FIX)-engineered human mesenchymal stromal cells encapsulated in RGD-alginate vs. fibrinogen-alginate microcapsules.

    Science.gov (United States)

    Sayyar, Bahareh; Dodd, Megan; Marquez-Curtis, Leah; Janowska-Wieczorek, Anna; Hortelano, Gonzalo

    2014-04-01

    The success of cell microencapsulation technology in tissue engineering and protein delivery applications depends on the viability and functionality of the encapsulated cells, which in turn are dependent upon cell/matrix interactions. In this work, we compared the viability of cord blood-derived mesenchymal stromal cells (CB MSCs), engineered to secrete factor IX (FIX) for hemophilia treatment, and encapsulated in arginine-glycine-aspartate (RGD)-alginate versus fibrinogen-alginate microcapsules. We evaluated the effect of the biomimetic matrix on cell attachment, proliferation, and secretion of FIX. Compared with nonsupplemented alginate matrix, RGD-alginate significantly enhanced the viability of the encapsulated MSCs. Further, cells in RGD-alginate displayed distinct attachment morphology, thus suggesting that RGD-alginate can potentially be used for the encapsulation of MSCs in tissue engineering applications that require enhanced cell attachment and viability. However, our data also showed that RGD-alginate microcapsules, in contrast to fibrinogen-alginate microcapsules, did not significantly improve cell proliferation of or FIX secretion by encapsulated MSCs. Our findings suggest that evidence of cell attachment alone may not accurately predict the functionality of cells in biomimetic microcapsules.

  14. Alginate gel particles-A review of production techniques and physical properties.

    Science.gov (United States)

    Ching, Su Hung; Bansal, Nidhi; Bhandari, Bhesh

    2017-04-13

    The application of hydrocolloid gel particles is potentially useful in food, chemical, and pharmaceutical industries. Alginate gel particles are one of the more commonly used hydrocolloid gel particles due to them being biocompatible, nontoxic, biodegradable, cheap, and simple to produce. They are particularly valued for their application in encapsulation. Encapsulation in alginate gel particles confers protective benefits to cells, DNA, nutrients, and microbes. Slow release of flavors, minerals, and drugs can also be achieved by encapsulation in gel particles. The particle size and shape of the gel particles are crucial for specific applications. In this review, current methods of producing alginate gel particles will be discussed, taking into account their advantages, disadvantages, scalability, and impact on particle size. The physical properties of alginate gel particles will determine the effectiveness in different application conditions. This review will cover the current understanding of the alginate biopolymer, gelation mechanisms and factors affecting release properties, gel strength, and rheology of the alginate gel particle systems.

  15. 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.

  16. Developing antimicrobial calcium alginate fibres from neem and papaya leaves extract.

    Science.gov (United States)

    Hussain, F; Khurshid, M F; Masood, R; Ibrahim, W

    2017-12-02

    The aim of this study was to evaluate an alternative approach to developing antimicrobial alginate fibres using plant extracts, such as those from neem and papaya leaves. Aqueous leaves extract from neem, papaya and their hybrid combinations were used as solvent to develop sodium alginate fibres. Sodium alginate polymer containing these extracts was extruded in a calcium chloride (CaCl2) bath to develop neem (NE), papaya (PE) and their hybrid combinations-based calcium alginate fibres (H-1 to H-5). The surface morphology, spectra, liquid absorption, tensile strength and antimicrobial activity of these developed fibres were measured. NE fibre showed greater tensile strength than PE. The liquid absorption property of all developed fibres decreased, but showed antibacterial properties against Staphylococcus aureus and reduced bacterial growth up to 85% when compared with pure calcium alginate fibre. Neem, papaya and hybrid extract-based calcium alginate fibres have the potential to be used as wound dressings.

  17. Alginate: Current Use and Future Perspectives in Pharmaceutical and Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Marta Szekalska

    2016-01-01

    Full Text Available Over the last decades, alginates, natural multifunctional polymers, have increasingly drawn attention as attractive compounds in the biomedical and pharmaceutical fields due to their unique physicochemical properties and versatile biological activities. The focus of the paper is to describe biological and pharmacological activity of alginates and to discuss the present use and future possibilities of alginates as a tool in drug formulation. The recent technological advancements with using alginates, issues related to alginates suitability as matrix for three-dimensional tissue cultures, adjuvants of antibiotics, and antiviral agents in cell transplantation in diabetes or neurodegenerative diseases treatment, and an update on the antimicrobial and antiviral therapy of the alginate based drugs are also highlighted.

  18. Effects of pH on the Shape of Alginate Particles and Its Release Behavior

    Directory of Open Access Journals (Sweden)

    Jui-Jung Chuang

    2017-01-01

    Full Text Available A vast majority of alginate particles exist as spheres in most practical uses, and both the particle shape and size are the key factors dominating the applications and performance of alginate gels. Therefore, it becomes an issue of great interest to investigate the aspheric alginate particles. As the first step, various shaped alginate particles were formed due to various pH values in gelation solutions. It was experimentally demonstrated that a low pH brought about an oblate shape, and particularly lower concentrations of both alginate and divalent cations resulted in a flattened oblate shape. Ba2+ acting as a cross-linker had a less impact on the particle shape than Ca2+ due to a higher affinity in alginate intermolecular cross-linking. With a larger surface area, an oblate particle offered a higher release rate than a spheric one.

  19. In situ processing and properties of nanostructured hydroxyapatite/alginate composite

    Science.gov (United States)

    Wang, Li; Li, Yue; Li, Chunzhong

    2009-04-01

    A series of hydroxyapatite/alginate (HA/Alg) nanocomposites with alginate amounts varying from 10 to 40 wt% were prepared through in situ hybridization technique. The inorganic phase in the composites was carbonate-substituted HA with low crystallinity. The crystallinity of HA decreased with the increase of alginate content. HA crystallites were needle-like in shape with a typical size of 20 to 50 nm in length and 5 nm in width. FT-IR spectroscopy indicated that the chemical interaction occurred between the mineral phase and the polymer matrix. As compared to pure HA without alginate, the composites showed more homogeneous microstructures, where HA nanocrystals were well embedded in alginate matrix. Among all the samples, the composite containing 30 wt% alginate exhibited a highly ordered three-dimensional network, similar to natural bone's microstructure.

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

    Science.gov (United States)

    Sarker, Bapi; Singh, Raminder; Silva, Raquel; Roether, Judith A; Kaschta, Joachim; Detsch, Rainer; Schubert, Dirk W; Cicha, Iwona; Boccaccini, Aldo R

    2014-01-01

    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.

  1. Relating physicochemical properties of alginate-HMP complexes to their performance as drug delivery systems.

    Science.gov (United States)

    Liu, Cheng-Mei; He, Xiao-Hong; Liang, Rui-Hong; Liu, Wei; Guo, Wen-Li; Chen, Jun

    2017-12-01

    This study aims to analyze the effect of physicochemical properties of alginate-high methoxyl pectin (HMP) complexes on their performance as drug delivery systems. Rheology, textural properties and swelling behavior of alginate-HMP complexes were determined. HMP alone showed weak gelling ability. As ratio of alginate increased, gel capability, hardness and adhesiveness of gels increased, but swelling rate decreased. Bovine serum albumin (BSA) was used as a model drug and entrapped in the alginate-HMP beads. Morphology of beads was correlated with adhesiveness. Drug loading content and encapsulation efficiency were related to electrostatic interactions between BSA and alginate-HMP complexes. Drug release profiles were correlated with both texture and swelling properties of alginate-HMP complexes and morphology of beads in simulated gastric fluids, while release in simulated intestinal fluids was affected by drug loading content. This study gives enlightenment that pre-selection of encapsulation materials may be achieved prior to encapsulation based on physicochemical properties of materials.

  2. Controllable generation and encapsulation of alginate fibers using droplet-based microfluidics.

    Science.gov (United States)

    Martino, Chiara; Statzer, Cyril; Vigolo, Daniele; deMello, Andrew J

    2016-01-07

    Herein we demonstrate the segmentation of alginate solution streams to generate alginate fibers of precisely controllable lengths between 200 and 1000 μm. Moreover, we demonstrate the subsequent encapsulation of the formed fibers within pL-volume microdroplets, produced within the same microfluidic device, in a direct manner. Finally, we show immediate and complete on-chip gelation of alginate fibers in a rapid and reproducible fashion.

  3. 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.

  4. pH-responsive alginate-based composite hydrogel beads for oral insulin delivery

    OpenAIRE

    HUI PENG LIM

    2017-01-01

    This research attempts to develop a pH-responsive alginate-based composite hydrogel beads for encapsulation and controlled delivery of oral insulin aspart through incorporation of κ-carrageenan as a reinforcement polymer and hydrophobic modification of alginate polymer. The alginate/κ-carrageenan composite hydrogel beads were able to fully retain the insulin in conditions mimicking the stomach and release the insulin in conditions mimicking the intestine at a constant rate. Bioactivity of ins...

  5. Fabrication of Freestanding Alginate Microfibers and Microstructures for Tissue Engineering Applications

    Science.gov (United States)

    Szymanski, John M; Feinberg, Adam W

    2014-01-01

    Natural biopolymers such as alginate have become important materials for a variety of biotechnology applications including drug delivery, cell encapsulation and tissue engineering. This expanding use has spurred the development of new approaches to engineer these materials at the nano- and microscales to better control cell interactions. Here we describe a method to fabricate freestanding alginate-based microfibers and microstructures with tunable geometries down to approximately 3 μm. To do this, a polydimethylsiloxane (PDMS) stamp is used to micromold alginate or alginate-fibrin blends onto a sacrificial layer of thermally-sensitive poly(N-isopropylacrylamide) (PIPAAm). A warm calcium chloride solution is then used to crosslink the alginate and upon cooling below the lower critical solution temperature (~32° C) the PIPAAm layer dissolves and releases the alginate or alginate-fibrin as freestanding microfibers and microstructures. Proof-of-concept experiments demonstrate that C2C12 myoblasts seeded onto the alginate-fibrin microfibers polarize along the fiber length forming interconnected cell strands. Thus, we have developed the ability to engineer alginate-based microstructured materials that can selectively bind cells and direct cellular assembly. PMID:24695323

  6. Mammalian Cell Encapsulation in Alginate Beads Using a Simple Stirred Vessel.

    Science.gov (United States)

    Hoesli, Corinne A; Kiang, Roger L J; Raghuram, Kamini; Pedroza, René G; Markwick, Karen E; Colantuoni, Antonio M R; Piret, James M

    2017-06-29

    Cell encapsulation in alginate beads has been used for immobilized cell culture in vitro as well as for immunoisolation in vivo. Pancreatic islet encapsulation has been studied extensively as a means to increase islet survival in allogeneic or xenogeneic transplants. Alginate encapsulation is commonly achieved by nozzle extrusion and external gelation. Using this method, cell-containing alginate droplets formed at the tip of nozzles fall into a solution containing divalent cations that cause ionotropic alginate gelation as they diffuse into the droplets. The requirement for droplet formation at the nozzle tip limits the volumetric throughput and alginate concentration that can be achieved. This video describes a scalable emulsification method to encapsulate mammalian cells in 0.5% to 10% alginate with 70% to 90% cell survival. By this alternative method, alginate droplets containing cells and calcium carbonate are emulsified in mineral oil, followed by a decrease in pH leading to internal calcium release and ionotropic alginate gelation. The current method allows the production of alginate beads within 20 min of emulsification. The equipment required for the encapsulation step consists in simple stirred vessels available to most laboratories.

  7. Evaluation of alginate purification methods: effect on polyphenol, endotoxin, and protein contamination.

    Science.gov (United States)

    Dusseault, Julie; Tam, Susan K; Ménard, Martin; Polizu, Stefania; Jourdan, Guillaume; Yahia, L'Hocine; Hallé, Jean-Pierre

    2006-02-01

    Alginate, a polysaccharide extracted from brown seaweed, is widely used for the microencapsulation of islets of Langerhans, allowing their transplantation without immunosuppression. This natural polymer is known to be largely contaminated. The implantation of islets encapsulated using unpurified alginate leads to the development of fibrotic cell overgrowth around the microcapsules and normalization of the blood glucose is restricted to a very short period if it is achieved at all. Several research groups have developed their own purification method and obtained relatively good results. No comparative evaluation of the efficiencies of these methods has been published. We conducted an evaluative study of five different alginate preparations: a pharmaceutical-grade alginate in its raw state, the same alginate after purification according to three different published methods, and a commercially available purified alginate. The results showed that all purification methods reduced the amounts of known contaminants, that is, polyphenols, endotoxins, and proteins, although with varying efficiencies. Increased viscosity of alginate solutions was observed after purification of the alginates. Despite a general efficiency in decreasing contamination levels, all of the purified alginates contained relatively high residual amounts of protein contaminants. Because proteins may be immunogenic, these residual proteins may have a role in persisting microcapsule immunogenicity.

  8. Drug release, preclinical and clinical pharmacokinetics relationships of alginate pellets prepared by melt technology.

    Science.gov (United States)

    Bose, Anirbandeep; Harjoh, Nurulaini; Pal, Tapan Kumar; Dan, Shubhasis; Wong, Tin Wui

    2016-01-01

    Alginate pellets prepared by the aqueous agglomeration technique experience fast drug dissolution due to the porous pre-formed calcium alginate microstructure. This study investigated in vitro drug release, preclinical and clinical pharmacokinetics relationships of intestinal-specific calcium acetate-alginate pellets against calcium-free and calcium carbonate-alginate pellets. Alginate pellets were prepared by solvent-free melt pelletization instead of aqueous agglomeration technique using chlorpheniramine maleate as model drug. A fast in situ calcium acetate dissolution in pellets resulted in rapid pellet breakup, soluble Ca(2+) crosslinking of alginate fragments and drug dissolution retardation at pH 1.2, which were not found in other pellet types. The preclinical drug absorption rate was lower with calcium acetate loaded than calcium-free alginate pellets. In human subjects, however, the extent and the rate of drug absorption were higher from calcium acetate-loaded pellets than calcium-free alginate pellets. The fine, dispersible and weakly gastric mucoadhesive calcium alginate pellets underwent fast human gastrointestinal transit. They released the drug at a greater rate than calcium-free pellets in the intestine, thereby promoting drug bioavailability. Calcium acetate was required as a disintegrant more than as a crosslinking agent clinically to promote pellet fragmentation, fast gastrointestinal transit and drug release in intestinal medium, and intestinal-specific drug bioavailability.

  9. Clinical and laboratory studies of the antacid and raft-forming properties of Rennie alginate suspension.

    Science.gov (United States)

    Tytgat, G N; Simoneau, G

    2006-03-15

    Acid pockets at the gastro-oesophageal junction escape buffering from meals in the stomach. Combining high-dose antacid with alginate may therefore be of benefit in gastro-oesophageal reflux disease. To characterize the antacid and raft-forming properties of Rennie alginate suspension (containing high-dose antacid and alginate; Bayer Consumer Care, Bladel, the Netherlands). The in vitro acid-neutralizing capacity of Rennie algniate was compared with Gaviscon (Reckitt Benckiser, Slough, UK) by pH-recorded HCl titration. Alginate raft weight formed in vitro at different pH was used to evaluate the pH dependency of raft formation with each product. A double-blind, placebo-controlled, randomized crossover study also compared the antacid activity of Rennie alginate vs. placebo in vivo using continuous intragastric pH monitoring in 12 healthy fasting volunteers. Compared with Gaviscon, Rennie alginate had a higher acid-neutralizing capacity, greater maximum pH and longer duration of antacid activity in vitro. However, the two products produced comparable alginate rafts at each pH evaluated. In vivo, Rennie alginate provided rapid, effective and long-lasting acid neutralization, with an onset of action of <5 min, and duration of action of almost 90 min. The dual mode of action of Rennie alginate offers an effective treatment option for mild symptomatic gastro-oesophageal reflux disease particularly considering recent findings regarding 'acid pockets'.

  10. Alginate/bacterial cellulose nanocomposite beads prepared using Gluconacetobacter xylinus and their application in lipase immobilization.

    Science.gov (United States)

    Kim, Ji Hyun; Park, Saerom; Kim, Hyungsup; Kim, Hyung Joo; Yang, Yung-Hun; Kim, Yong Hwan; Jung, Sang-Kyu; Kan, Eunsung; Lee, Sang Hyun

    2017-02-10

    Alginate/bacterial cellulose nanocomposite beads, with well-controlled size and regular spherical shapes, were prepared in a simple manner by entrapping Gluconacetobacter xylinus in barium alginate hydrogel beads, followed by cultivation of the entrapped cells in culture media with a low sodium ion concentration. The entire surface of the alginate hydrogel beads containing the cells was covered with cellulose fibers (∼30nm) after 36h of cultivation. The cellulose crystallinity index of the alginate/bacterial cellulose beads was 0.7, which was slightly lower than that of bacterial cellulose prepared by cultivating dispersed cells. The water vapor sorption capacity of the alginate/bacterial cellulose beads increased significantly from 0.07 to 38.00 (g/g dry bead) as cultivation time increased. These results clearly indicate that alginate/bacterial cellulose beads have a much higher surface area, crystallinity, and water-holding capacity than alginate beads. The immobilization of lipase on the surface of the nanocomposite beads was also investigated as a potential application of this system. The activity and specific activity of lipase immobilized on alginate/bacterial cellulose beads were 2.6- and 3.8-fold higher, respectively, than that of lipase immobilized on cellulose beads. The alginate/bacterial cellulose nanocomposite beads prepared in this study have several potential applications in the biocatalytic, biomedical, and pharmaceutical fields because of their biocompatibility, biodegradability, high crystallinity, and large surface area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. 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.

  12. 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.

  13. 3D-Printable Bioactivated Nanocellulose-Alginate Hydrogels.

    Science.gov (United States)

    Leppiniemi, Jenni; Lahtinen, Panu; Paajanen, Antti; Mahlberg, Riitta; Metsä-Kortelainen, Sini; Pinomaa, Tatu; Pajari, Heikki; Vikholm-Lundin, Inger; Pursula, Pekka; Hytönen, Vesa P

    2017-07-05

    We describe herein a nanocellulose-alginate hydrogel suitable for 3D printing. The composition of the hydrogel was optimized based on material characterization methods and 3D printing experiments, and its behavior during the printing process was studied using computational fluid dynamics simulations. The hydrogel was biofunctionalized by the covalent coupling of an enhanced avidin protein to the cellulose nanofibrils. Ionic cross-linking of the hydrogel using calcium ions improved the performance of the material. The resulting hydrogel is suitable for 3D printing, its mechanical properties indicate good tissue compatibility, and the hydrogel absorbs water in moist conditions, suggesting potential in applications such as wound dressings. The biofunctionalization potential was shown by attaching a biotinylated fluorescent protein and a biotinylated fluorescent small molecule via avidin and monitoring the material using confocal microscopy. The 3D-printable bioactivated nanocellulose-alginate hydrogel offers a platform for the development of biomedical devices, wearable sensors, and drug-releasing materials.

  14. Gelatin methacrylate-alginate hydrogel with tunable viscoelastic properties

    Directory of Open Access Journals (Sweden)

    Yong X. Chen

    2017-02-01

    Full Text Available Although native extracellular matrix (ECM is viscoelastic, synthetic biomaterials used in biomedical engineering to mimic ECM typically exhibit a purely elastic response when an external strain is applied. In an effort to truly understand how living cells interact with surrounding ECM matrix, new biomaterials with tunable viscoelastic properties continue to be developed. Here we report the synthesis and mechanical characterization of a gelatin methacrylate-alginate (Gel-Alg composite hydrogel. Results obtained from creep and compressive tests reveal that the alginate component of Gel-Alg composite, can be effectively crosslinked, un-crosslinked and re-crosslinked by adding or chelating Ca2+ ions. This work demonstrates that Gel-Alg is capable of tuning its viscoelastic strain and elastic recovery properties, and can be potentially used to design ECM-mimicking hydrogels.

  15. Separation of Uranium by an Extractant Encapsulated Magnetic Alginate Gels

    Science.gov (United States)

    Portakal, Z.; Gok, C.; Aytas, S.

    The aim of this work is to prepare environmentally friendly and practically applicable alginate magnetic biopolymers encapsulated tri-n-butyl phosphate (TBP) for the removal uranium ions. Some important process parameters such as initial pH, initial U(VI) concentration, adsorbent dosage, time, temperature and sorption isotherms for uranium uptake were studied and the thermodynamic parameters for U(VI) were determined.

  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. Characterization of alginate-brushite in-situ hydrogel composites

    Energy Technology Data Exchange (ETDEWEB)

    Dabiri, Seyed Mohammad Hossein [Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa (Italy); Lagazzo, Alberto; Barberis, Fabrizio [Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa (Italy); Farokhi, Mehdi [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Finochio, Elisabetta [Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa (Italy); Pastorino, Laura [Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa (Italy)

    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 14 days. 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. - Highlights: • Alginate-brushite hydrogel composites were obtained through an in-situ process • The brushite crystals started forming at pH value of 6 • The increase in the initial concentration of phosphate precursor resulted in more crystalline structure • Samples prepared at pH value of 8 had the most stable crystalline structure • Brushite crystals promoted the biocompatibility of alginate.

  18. Gelatin methacrylate-alginate hydrogel with tunable viscoelastic properties

    OpenAIRE

    Yong X. Chen; Brian Cain; Pranav Soman

    2017-01-01

    Although native extracellular matrix (ECM) is viscoelastic, synthetic biomaterials used in biomedical engineering to mimic ECM typically exhibit a purely elastic response when an external strain is applied. In an effort to truly understand how living cells interact with surrounding ECM matrix, new biomaterials with tunable viscoelastic properties continue to be developed. Here we report the synthesis and mechanical characterization of a gelatin methacrylate-alginate (Gel-Alg) composite hydrog...

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

    Science.gov (United States)

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

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. IN VITRO EVALUATION OF FLUORIDE RELEASE OF JELTRATE® DENTAL ALGINATE

    Directory of Open Access Journals (Sweden)

    Matheus Melo Pithon

    2009-04-01

    Full Text Available Objective: To evaluate of fluoride release from Jeltrate alginate®. Materials and Methods: Four Trademarks of alginate were divided in four groups: conventional Jeltrate®, Plus Jeltrate®, Chromatic Jeltrate® and Chromatic Ortho Jeltrate®. The alginates were handled following the guidelines of the manufacturers. After this was followed by the construction of evidence bodies using silicone molds of the dimensions of 4 mm in diameter and 4mm in height. After take prey, the evidence bodies were removed from the molds and placed in container with 10 ml of ultra purified water, for 2 min. The fluoride release was measured by selective ion electrode connected to an analyzer of ions. Results: The Plus Jeltrate® showed a higher releasing fluoride 247.85 µg/cm2 followed by Chromatic Ortho Jeltrate® (217.83 µg/cm2, Chromatic Jeltrate ® (138.21 µg/cm2 and Jeltrate® (79.61 µg/cm2. Conclusion: Plus Jeltrate® had the best performance in releasing fluoride, followed by Chromatic Ortho Jeltrate®, Chromatic Jeltrate® and conventional Jeltrate®..

  1. Injectable alginate hydrogels for cell delivery in tissue engineering.

    Science.gov (United States)

    Bidarra, Sílvia J; Barrias, Cristina C; Granja, Pedro L

    2014-04-01

    Alginate hydrogels are extremely versatile and adaptable biomaterials, with great potential for use in biomedical applications. Their extracellular matrix-like features have been key factors for their choice as vehicles for cell delivery strategies aimed at tissue regeneration. A variety of strategies to decorate them with biofunctional moieties and to modulate their biophysical properties have been developed recently, which further allow their tailoring to the desired application. Additionally, their potential use as injectable materials offers several advantages over preformed scaffold-based approaches, namely: easy incorporation of therapeutic agents, such as cells, under mild conditions; minimally invasive local delivery; and high contourability, which is essential for filling in irregular defects. Alginate hydrogels have already been explored as cell delivery systems to enhance regeneration in different tissues and organs. Here, the in vitro and in vivo potential of injectable alginate hydrogels to deliver cells in a targeted fashion is reviewed. In each example, the selected crosslinking approach, the cell type, the target tissue and the main findings of the study are highlighted. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Optimization of polyphenol oxidase immobilization in copper alginate beads.

    Science.gov (United States)

    Kocaturk, Selin; Yagar, Hulya

    2010-05-01

    Polyphenol oxidase (PPO, EC 1.14.18.1) was isolated from artichoke head (Cynara scolymus L.) by using 0.1 M Tris-HCl buffer (pH 7.0), concentrated by (NH4)2SO4 precipitation, and immobilized in copper-alginate beads. Immobilization yield was determined to be 70%. The cresolase and catecholase activities of enzyme immobilized at optimum immobilization conditions were found to be 13.3 and 670 U g beads min(-1), respectively. Effects of immobilization conditions such as alginate concentration, CaCl2 concentration, amount of loading enzyme, bead size, and amount of beads on enzymatic activity were investigated. Optimum alginate and CuCl2 concentration were found to be 2 % and 3 % (w/v), respectively. Using bead (diameter 3 mm) amount of 0.25 g maximum enzyme activities were observed for both polyphenol activities. The initial concentrations of loading free enzyme were 6.5 U mL(-1) and 5815 U mL(-1) for cresolase activity and catecholase activities, respectively. Beads prepared at optimum immobilization conditions were suitable for up to 8 repeated uses.

  3. The suppression of gastro-oesophageal reflux by alginates.

    Science.gov (United States)

    Dettmar, P W; Hampson, F C; Taubel, J; Lorch, U; Johnstone, L M; Sykes, J; Berry, P J

    2007-10-01

    The aim of this study was to compare alginate products with the same amount of active ingredients but different dosage forms, in the suppression of reflux provoked by a standard meal in healthy human volunteers, using ambulatory oesophageal pH monitoring. This was a single centre, randomised, open, three-period crossover, controlled study comparing Gaviscon Advance (10 ml) with a control (10 ml water) and with a new tablet product containing the same active ingredients as Gaviscon Advance. Volunteers who had oesophageal pH Gaviscon Advance and control in the mean angular transformed percentage of time for which oesophageal pH fell below four was statistically significant (p pH fell below four. There were also no significant differences between the two alginate dosage forms in the angular transformed percentage of time for which oesophageal pH fell below five and in the log-transformed number of occasions on which oesophageal pH fell below four and five. The study shows that alginate reflux suppressants containing a low amount of antacid are effective in suppressing acid reflux and that suspension and tablet forms are able to give equivalent acid suppression.

  4. ENTRAPMENT OF FLUORESCENT E. COLI CELLS IN ALGINATE GEL

    Directory of Open Access Journals (Sweden)

    T. VINTILA

    2009-05-01

    Full Text Available By this experiment we will demonstrate the possibility to obtain genetically modified microbial strains that can be used as markers in different studies. The trait transferred in this study is the fluorescence in UV light expressed by a gene isolated from jellyfish. This gene was insered into a plasmid carrying ampiciline resistance and in the operon for arabinose fermentation. The plasmid was called pGLO. E coli HB101 K-12, ampicillin resistant colonies has been obtained. The colonies on the LB/amp/ara plate fluoresce green under UV light and the transformed colonies can grow on ampicillin. Transformation efficiency = 362 transformed colonies/ μg DNA. The cells where immobilized by entrapment in alginate gel to study the phenomenon involved in cells immobilization. After immobilization in alginate gel, 5x104 cells of E. coli pGLO / capsule and 1,4 x 105 cells of E. coli HB101/capsule has been found. Fluorescent microscopy revealed the presence of pGLO carrying cells into the capsules. After cultivation of alginate capsules containing E. coli in LB broth, and fluorescent microscopy of the capsule sections, several observations of the phenomenon involved in continuous fermentation using biocatalysts in has been made. These cells grow and migrate to the cortical part of the matrix where they are immobilized.

  5. Alginate Immobilization of Metabolic Enzymes (AIME) for High ...

    Science.gov (United States)

    Alginate Immobilization of Metabolic Enzymes (AIME) for High-Throughput Screening Assays DE DeGroot, RS Thomas, and SO SimmonsNational Center for Computational Toxicology, US EPA, Research Triangle Park, NC USAThe EPA’s ToxCast program utilizes a wide variety of high-throughput screening (HTS) assays to assess chemical perturbations of molecular and cellular endpoints. A key criticism of using HTS assays for toxicity assessment is the lack of xenobiotic metabolism (XM) which precludes both metabolic detoxification as well as bioactivation of chemicals tested in vitro thereby mischaracterizing the potential risk posed by these chemicals. To address this deficiency, we have developed an extracellular platform to retrofit existing HTS assays with XM activity. This platform utilizes the S9 fraction of liver homogenate encapsulated in an alginate gel network which reduces the cytotoxicity caused by direct addition of S9 to cells in culture. Alginate microspheres containing encapsulated human liver S9 were cross-linked to solid supports extending from a 96-well plate lid and were assayed using a pro-luciferin substrate specific for CYP3A4 (IPA). We demonstrate that S9 was successfully encapsulated and remained enzymatically active post-encapsulation with 5-10X the CYP3A4 activity as compared to 1 µg solubilized human liver S9. Ketoconazole, a known inhibitor of human CYP3A4, inhibited CYP3A4 activity in a concentration-dependent manner (IC50: 0.27 µM) and inhibiti

  6. 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.

  7. Alginate microparticles as novel carrier for oral insulin delivery.

    Science.gov (United States)

    Reis, Catarina Pinto; Ribeiro, António J; Neufeld, Ronald J; Veiga, Francisco

    2007-04-01

    Alginate microparticles produced by emulsification/internal gelation were investigated as a promising carrier for insulin delivery. The procedure involves the dispersion of alginate solution containing insulin protein, into a water immiscible phase. Gelation is triggered in situ by instantaneous release of ionic calcium from carbonate complex via gentle pH adjustment. Particle size is controlled through the emulsification parameters, yielding insulin-loaded microparticles. Particle recovery was compared using several washing protocols. Recovery strategies are proposed and the influence on particle mean size, morphology, recovery yield (RY), encapsulation efficiency, insulin release profile, and structural integrity of released insulin were evaluated. Spherical micron-sized particles loaded with insulin were produced. The recovery process was optimized, improving yield, and ensuring removal of residual oil from the particle surface. The optimum recovery strategy consisted in successive washing with a mixture of acetone/hexane/isopropanol coupled with centrifugation. This strategy led to small spherical particles with an encapsulation efficiency of 80% and a RY around 70%. In vitro release studies showed that alginate itself was not able to suppress insulin release in acidic media; however, this strategy preserves the secondary structure of insulin. Particles had a mean size lower than the critical diameter necessary to be orally absorbed through the intestinal mucosa followed by their passage to systemic circulation and thus can be considered as a promising technology for insulin delivery. (c) 2006 Wiley Periodicals, Inc.

  8. Science of landscape restoration

    CSIR Research Space (South Africa)

    De Wet, Benita

    2011-11-01

    Full Text Available or email bdewet@ csir.co.za. The science of landscape restoration Over the last two decades the ecological restoration of industrial land has developed into a specialist science combined with highly sophisticated management activities. A prime...

  9. The preservation of islet with alginate encapsulation in the process of transportation.

    Science.gov (United States)

    Li, Na; Zhang, Ying; Xiu, Zhilong; Wang, Yu; Chen, Li; Wang, Shujun; Li, Shen; Guo, Xin; Ma, Xiaojun

    2015-01-01

    Restoration of insulin secretion by transplantation of isolated islets is a treatment for type Ι diabetes mellitus. One of the major issues with clinical treatment of islet transplantation is how to maintain islet viability during transportation from the donor to the patient. We developed a method that uses alginate encapsulation to protect islets from mechanical damage during shipment. We tested several variables for their impact on islet viability during transportation and used the significant variable to build a response surface methodology (RSM) model by the Box-Behnken design method. This type of model is a mathematical and statistical technique that we used to optimize the conditions for islet viability during shipment. In this study, the factors that significantly affected islet survival rate were incubation time, serum concentration, and preservation time. Then, an empirical model was built to optimize conditions of the islets for shipping according to the responses of the effect factors with RSM. This model can be used to predict the islet survival rate and can serve as a guide for optimizing the transportation method of islets and increasing the success rate of the transplant procedure. Copyright © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  10. Global Ecosystem Restoration Index

    DEFF Research Database (Denmark)

    Fernandez, Miguel; Garcia, Monica; Fernandez, Nestor

    2015-01-01

    The Global ecosystem restoration index (GERI) is a composite index that integrates structural and functional aspects of the ecosystem restoration process. These elements are evaluated through a window that looks into a baseline for degraded ecosystems with the objective to assess restoration...

  11. Effect of chitosan coating on a bacteria-based alginate microrobot.

    Science.gov (United States)

    Park, Sung Jun; Lee, Yu Kyung; Cho, Sunghoon; Uthaman, Saji; Park, In-Kyu; Min, Jung-Joon; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-04-01

    To develop an efficient bacteria-based microrobot, first, therapeutic bacteria should be encapsulated into microbeads using biodegradable and biocompatible materials; second, the releasing rate of the encapsulated bacteria for theragnostic function should be regulated; and finally, flagellated bacteria should be attached on the microbeads to ensure the motility of the microrobot. For the therapeutic bacteria encapsulation, an alginate can be a promising candidate as a biodegradable and biocompatible material. Owing to the non-regulated releasing rate of the encapsulated bacteria in alginate microbeads and the weak attachment of flagellated bacteria on the surface of alginate microbeads, however, the alginate microbeads cannot be used as effective cargo for a bacteria-based microrobot. In this paper, to enhance the stability of the bacteria encapsulation and the adhesion of flagellated bacteria in alginate microbeads, we performed a surface modification of alginate microbeads using chitosan coating. The bacteria-encapsulated alginate microbeads with 1% chitosan coating maintained their structural integrity up to 72 h, whereas the control alginate microbead group without chitosan coating showed severe degradations after 24 h. The chitosan coating in alginate microbeads shows the enhanced attachment of flagellated bacteria on the surface of alginate microbeads. The bacteria-actuated microrobot with the enhanced flagellated bacteria attachment could show approximately 4.2 times higher average velocities than the control bacteria-actuated microrobot without chitosan coating. Consequently, the surface modification using chitosan coating enhanced the structural stability and the motility of the bacteria-based alginate microrobots. © 2014 Wiley Periodicals, Inc.

  12. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. 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.

  14. 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.

  15. One-step purification and characterization of alginate lyase from a clinical Pseudomonas aeruginosa with destructive activity on bacterial biofilm.

    Science.gov (United States)

    Ghadam, Parinaz; Akhlaghi, Fatemeh; Ali, Ahya Abdi

    2017-05-01

    Pseudomonas aeruginosa is a Gram-negative and aerobic rod bacterium that displays mucoid and non-mucoid phenotype. Mucoid strains secrete alginate, which is the main agent of biofilms in chronic P. aeruginosa infections, show high resistance to antibiotics; consequently, the biological disruption of mucoid P. aeruginosa biofilms is an attractive area of study for researchers. Alginate lyase gene (algl) is a member of alginate producing operon which by glycosidase activity produces primer for other enzymes in this cluster. Also this activity can destroy the extracellular alginate; therefore this enzyme participates in alginate production and destruction pathway. Alginate lyase causes detachment of a biofilm by reducing its adhesion to the surfaces, and increases phagocytosis and antibiotic susceptibility. In this study, alginate lyase was purified in just one step and its properties were investigated. The purification was done by affinity chromatography, analysed by SDS-PAGE, and its effect on P. aeruginosa biofilms was surveyed by micro titer plate assay and SEM. The substrate specificity of the enzyme was determined by PCR. Alginate lyase from isolate 48 was purified in one step. It is more thermally resistant than alginate lyase from Pseudomonas aeruginosa PAO1 and poly M, poly G and poly MG alginate were the substrate of this enzyme. Moreover, it has an eradication effect on biofilms from P. aeruginosa 48 and PAO1. In this study an alginate lyase with many characteristics suitable in medicine such as thermal stability, effective on poly M alginate, and bacterial biofilm destructive was introduced and purified.

  16. Analysis of extracellular alginate lyase and its gene from a marine bacterial strain, Pseudoalteromonas atlantica AR06.

    Science.gov (United States)

    Matsushima, Ryoji; Danno, Hiroko; Uchida, Motoharu; Ishihara, Kenji; Suzuki, Toshiyuki; Kaneniwa, Masaki; Ohtsubo, Yoshiyuki; Nagata, Yuji; Tsuda, Masataka

    2010-03-01

    Pseudoalteromonas atlantica AR06 is a marine bacterial strain that can utilize alginate as a sole source of carbon and energy. The extracellular protein fraction prepared from the AR06 cultivation media exhibited alginate lyase activity to depolymerize the alginate molecules having homopolymeric and heteropolymeric forms of mannuronate and guluronate so as to mainly convert into the dimer to tetramer. A DNA fragment encoding a portion of alginate lyase was amplified from AR06 genomic DNA by PCR using a set of degenerated primers, and then the whole alginate lyase gene, named alyA, and its flanking regions were obtained from a cosmid library of AR06 genomic DNA. The alyA mutant of AR06 showed (1) the loss of alginate depolymerization activity on alginate agar plate and (2) significant growth defects in alginate minimal medium; these defects were complemented by the introduction of the alyA gene. Furthermore, zymography and biochemical analyses revealed that three extracellular protein bands of AR06 had alginate lyase activities and that all three protein bands were derived from the nascent alyA gene product. These results clearly indicated that the alyA gene greatly contributes to the assimilation of alginate in AR06. The transcription of the alyA gene was induced by the presence of alginate in minimal medium, but its obvious induction was not observed in rich medium even in the presence of alginate.

  17. Response of bacterial communities from California coastal waters to alginate particles and an alginolytic Alteromonas macleodii strain.

    Science.gov (United States)

    Mitulla, Maximilian; Dinasquet, Julie; Guillemette, Ryan; Simon, Meinhard; Azam, Farooq; Wietz, Matthias

    2016-12-01

    Alginate is a major cell wall polysaccharide from marine macroalgae and nutrient source for heterotrophic bacteria. Alginate can form gel particles in contact with divalent cations as found in seawater. Here, we tested the hypothesis that alginate gel particles serve as carbon source and microhabitat for marine bacteria by adding sterile alginate particles to microcosms with seawater from coastal California, a habitat rich in alginate-containing macroalgae. Alginate particles were rapidly colonized and degraded, with three- to eightfold higher bacterial abundances and production among alginate particle-associated (PA) bacteria. 16S rRNA gene amplicon sequencing showed that alginate PA bacteria were enriched in OTUs related to Cryomorphaceae, Saprospiraceae (Bacteroidetes) and Phaeobacter (Alphaproteobacteria) towards the end of the experiment. In microcosms amended with alginate particles and the proficient alginolytic bacterium Alteromonas macleodii strain 83-1, this strain dominated the community and outcompeted Cryomorphaceae, Saprospiraceae and Phaeobacter, and PA hydrolytic activities were over 50% higher. Thus, alginolytic activity by strain 83-1 did not benefit non-alginolytic strains by cross-feeding on alginate hydrolysis or other metabolic products. Considering the global distribution and extensive biomass of alginate-containing macroalgae, the observed bacterial dynamics associated with the utilization and remineralization of alginate microhabitats promote the understanding of carbon cycling in macroalgae-rich waters worldwide. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Restoring the incisal edge.

    Science.gov (United States)

    Terry, Douglas A

    2005-01-01

    Restorative dentistry evolves with each development of new material and innovative technique. Selection of improved restorative materials that simulate the physical properties and other characteristics of natural teeth, in combination with restorative techniques such as the proximal adaptation and incremental layering, provide the framework that ensures the optimal development of an esthetic restoration. These advanced placement techniques offer benefits such as enhanced chromatic integration, polychromatism, ideal anatomical form and function, optimal proximal contact, improved marginal integrity and longer lasting directly placed composite restorations. The purpose of this article is to give the reader a better understanding of the complex restorative challenge in achieving true harmonization of the primary parameters in esthetics (that is, color, shape and texture) represented by the replacement of a single anterior tooth. The case presented demonstrates the restoration of a Class IV fracture integrating basic adhesive principles with these placement techniques and a recently developed nanoparticle hybrid composite resin system (Premise, Kerr/Sybron, Orange, CA). The clinical presentation describes preoperative considerations, tooth preparation, development of the body layer, internal characterization with tints, development of the artificial enamel layer, shaping and contouring, and polishing of a Class IV composite restoration. The clinical significance is that anterior tooth fractures can be predictably restored using contemporary small particle hybrid composite resin systems with the aforementioned restorative techniques. These placement techniques when used with proper attention to preparation design, adhesive protocol and finishing and polishing procedures, allow the clinician to successfully restore form, function and esthetics to the single anterior tooth replacement.

  19. Alginate as a cell culture substrate for growth and differentiation of human retinal pigment epithelial cells.

    Science.gov (United States)

    Heidari, Razeih; Soheili, Zahra-Soheila; Samiei, Shahram; Ahmadieh, Hamid; Davari, Maliheh; Nazemroaya, Fatemeh; Bagheri, Abouzar; Deezagi, Abdolkhalegh

    2015-03-01

    The purpose of this study was to evaluate retinal pigment epithelium (RPE) cells' behavior in alginate beads that establish 3D environment for cellular growth and mimic extracellular matrix versus the conventional 2D monolayer culture. RPE cells were encapsulated in alginate beads by dripping alginate cell suspension into CaCl2 solution. Beads were suspended in three different media including Dulbecco's modified Eagle's medium (DMEM)/F12 alone, DMEM/F12 supplemented with 10 % fetal bovine serum (FBS), and DMEM/F12 supplemented with 30 % human amniotic fluid (HAF). RPE cells were cultivated on polystyrene under the same conditions as controls. Cell phenotype, cell proliferation, cell death, and MTT assay, immunocytochemistry, and real-time RT-PCR were performed to evaluate the effect of alginate on RPE cells characteristics and integrity. RPE cells can survive and proliferate in alginate matrixes. Immunocytochemistry analysis exhibited Nestin, RPE65, and cytokeratin expressions in a reasonable number of cultured cells in alginate beads. Real-time PCR data demonstrated high levels of Nestin, CHX10, RPE65, and tyrosinase gene expressions in RPE cells immobilized in alginate when compared to 2D monolayer culture systems. The results suggest that alginate can be used as a reliable scaffold for maintenance of RPE cells' integrity and in vitro propagation of human retinal progenitor cells for cell replacement therapies in retinal diseases.

  20. The influence of mixing methods and disinfectant on the physical properties of alginate impression materials.

    NARCIS (Netherlands)

    Dreesen, K.; Kellens, A.; Wevers, M.; Thilakarathne, P.J.; Willems, G.

    2013-01-01

    The aims of this in vitro study were to quantify the effect of manual versus automatic mixing and of using a disinfectant on mechanical properties of three different alginate impression materials. Two of the three alginates tested were especially developed for orthodontic use: Orthotrace(R) and

  1. Clinical and laboratory studies of the antacid and raft-forming properties of Rennie alginate suspension

    NARCIS (Netherlands)

    Tytgat, G. N.; Simoneau, G.

    2006-01-01

    BACKGROUND: Acid pockets at the gastro-oesophageal junction escape buffering from meals in the stomach. Combining high-dose antacid with alginate may therefore be of benefit in gastro-oesophageal reflux disease. AIM: To characterize the antacid and raft-forming properties of Rennie alginate

  2. Photocrosslinked alginate with hyaluronic acid hydrogels as vehicles for mesenchymal stem cell encapsulation and chondrogenesis.

    Science.gov (United States)

    Coates, Emily E; Riggin, Corinne N; Fisher, John P

    2013-07-01

    Ionic crosslinking of alginate via divalent cations allows for high viability of an encapsulated cell population, and is an effective biomaterial for supporting a spherical chondrocyte morphology. However, such crosslinking chemistry does not allow for injectable and stable hydrogels which are more appropriate for clinical applications. In this study, the addition of methacrylate groups to the alginate polymer chains was utilized so as to allow the free radical polymerization initiated by a photoinitiator during UV light exposure. This approach establishes covalent crosslinks between methacrylate groups instead of the ionic crosslinks formed by the calcium in unmodified alginate. Although this approach has been well described in the literature, there are currently no reports of stem cell differentiation and subsequent chondrocyte gene expression profiles in photocrosslinked alginate. In this study, we demonstrate the utility of photocrosslinked alginate hydrogels containing interpenetrating hyaluronic acid chains to support stem cell chondrogenesis. We report high cell viability and no statistical difference in metabolic activity between mesenchymal stem cells cultured in calcium crosslinked alginate and photocrosslinked alginate for up to 10 days of culture. Furthermore, chondrogenic gene markers are expressed throughout the study, and indicate robust differentiation up to the day 14 time point. At early time points, days 1 and 7, the addition of hyaluronic acid to the photocrosslinked scaffolds upregulates gene markers for both the chondrocyte and the superficial zone chondrocyte phenotype. Taken together, we show that photocrosslinked, injectable alginate shows significant potential as a delivery mechanism for cell-based cartilage repair therapies. Copyright © 2012 Wiley Periodicals, Inc.

  3. 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...

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

    Directory of Open Access Journals (Sweden)

    Yu-Zhong Zhang

    2012-11-01

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

  5. 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

  6. Hollow fiber dead-end ultrafiltration: Influence of ionic environment on filtration of alginates

    NARCIS (Netherlands)

    van de Ven, W.J.C.; van 't Sant, K.; Punt, Ineke G.M.; Zwijnenburg, A.; Kemperman, Antonius J.B.; van der Meer, Walterus Gijsbertus Joseph; Wessling, Matthias

    2008-01-01

    We analyze the filterability of sodium alginate solutions in different ionic environments as a function of the operational flux. The alginates serve as a model component for polysaccharides in feed water. Next to filtration characteristics, the fouling reversibility was studied by employing strictly

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

    Science.gov (United States)

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

    2016-07-01

    Marine, hybrid constructs of porous scaffolds from fibrillized jellyfish collagen and alginate hydrogel are mimicking both of the main tissue components of cartilage, thus being a promising approach for chondrogenic differentiation of human mesenchymal stem cells (hMSC). Investigating their potential for articular cartilage repair, the present study examined scaffolds being either infiltrated with an alginate-cell-suspension (ACS) or seeded with hMSC and embedded in alginate after cell adhesion (EAS). Hybrid constructs with 2×10(5) and 4.5×10(5)hMSC/scaffold were compared to hMSC encapsulated in pure alginate discs, both chondrogenically stimulated for 21days. Typical round, chondrocyte-like morphology was observed in pure alginate gels and ACS scaffolds, while cells in EAS were elongated and tightly attached to the collagen pores. Col 2 gene expression was comparable in all scaffold types examined. However, the Col 2/Col 1 ratio was higher for pure alginate discs and ACS scaffolds compared to EAS. In contrast, cells in EAS scaffolds displayed higher gene expression of Sox 9, Col 11 and ACAN compared to ACS and pure alginate. Secretion of sulfated glycosaminoglycans (sGAG) was comparable for ACS and EAS scaffolds. In conclusion hybrid constructs of jellyfish collagen and alginate support hMSC chondrogenic differentiation and provide more stable and constructs compared to pure hydrogels. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. PEI-alginate nanocomposites as efficient in vitro gene transfection agents.

    Science.gov (United States)

    Patnaik, Soma; Aggarwal, Anita; Nimesh, Surendra; Goel, Anita; Ganguli, Munia; Saini, Neeru; Singh, Y; Gupta, K C

    2006-09-12

    The positive charge on PEI was partially shielded by forming ionic nanocomposites with a polysaccharide, alginic acid, in aqueous solution, bypassing tedious chemical synthesis. The content of alginic acid was varied systematically to obtain a series of nanocomposites. The nanocomposites were first characterized by assessing the surface charge (zeta potential), size (DLS) and morphology (AFM) followed by evaluation for their DNA interaction ability, cytotoxicity and transfection efficiency on various cell lines. The transfection efficiency of PEI-alginate (6.26%) nanocomposites improved dramatically (2-16-fold over native PEI) in all the cell lines studied. However, a decrease in transfection efficiency was observed on deviating from this optimal concentration of alginic acid in nanocomposites. Cytotoxicity of PEI-alginate/DNA complexes was nearly abolished on increasing the concentration of alginic acid in nanocomposites. PEI-alginate (6.26%) nanocomposites also delivered SiRNAs efficiently into mammalian cells, resulting in 80% suppression of GFP expression. The cellular uptake and endosomal escape of PEI-alginate nanocomposites and PEI were found to follow a similar route when transfection was carried out in presence of chloroquine, bafilomycin A1, cytochalasin B and methyl-beta-cyclodextrin. The results demonstrate a versatile vector that can be used for efficient cytoplasmic delivery of a broad range of nucleic acids.

  9. Ultrapure alginate anti-adhesion gel does not impair colon anastomotic strength

    NARCIS (Netherlands)

    Chaturvedi, A.A.; Lomme, R.M.L.M.; Hendriks, T.; Goor, H. van

    2014-01-01

    BACKGROUND: Ultrapure alginate gel is promising in terms of adhesion prevention. Because anti-adhesive barriers have been shown to disturb healing of bowel anastomoses, the effect of ultrapure alginate gel on the repair of colon anastomoses was studied. MATERIALS AND METHODS: In 102 male Wistar

  10. The effect of chitosan molecular weight on the properties of alginate ...

    African Journals Online (AJOL)

    Purpose: The aim of the present study was to investigate the effect of chitosan molecular weight on size, size distribution, release rate, mucoadhesive properties and electrostatic bonding of alginate/chitosan microparticles containing prednisolone. Methods: Three mucoadhesive alginate/chitosan microparticle formulations, ...

  11. Screening of alginate lyase-excreting microorganisms from the surface of brown algae.

    Science.gov (United States)

    Wang, Mingpeng; Chen, Lei; Zhang, Zhaojie; Wang, Xuejiang; Qin, Song; Yan, Peisheng

    2017-12-01

    Alginate lyase is a biocatalyst that degrades alginate to produce oligosaccharides, which have many bioactive functions and could be used as renewable biofuels. Here we report a simple and sensitive plate assay for screening alginate lyase-excreting microorganisms from brown algae. Brown algae Laminaria japonica, Sargassum horneri and Sargassum siliquatrum were cultured in sterile water. Bacteria growing on the surface of seaweeds were identified and their capacity of excreting alginate lyase was analyzed. A total of 196 strains were recovered from the three different algae samples and 12 different bacterial strains were identified capable of excreting alginate lyases. Sequence analysis of the 16S rRNA gene revealed that these alginate lyase-excreting strains belong to eight genera: Paenibacillus (4/12), Bacillus (2/12), Leclercia (1/12), Isoptericola (1/12), Planomicrobium (1/12), Pseudomonas (1/12), Lysinibacillus (1/12) and Sphingomonas (1/12). Further analysis showed that the LJ-3 strain (Bacillus halosaccharovorans) had the highest enzyme activity. To our best knowledge, this is the first report regarding alginate lyase-excreting strains in Paenibacillus, Planomicrobium and Leclercia. We believe that our method used in this study is relatively easy and reliable for large-scale screening of alginate lyase-excreting microorganisms.

  12. A rapid, sensitive, simple plate assay for detection of microbial alginate lyase activity.

    Science.gov (United States)

    Sawant, Shailesh S; Salunke, Bipinchandra K; Kim, Beom Soo

    2015-09-01

    Screening of microorganisms capable of producing alginate lyase enzyme is commonly carried out by investigating their abilities to grow on alginate-containing solid media plates and occurrence of a clearance zone after flooding the plates with agents such as 10% (w/v) cetyl pyridinium chloride (CPC), which can form complexes with alginate. Although the CPC method is good, advantageous, and routinely used, the agar in the media interferes with the action of CPC, which makes judgment about clearance zones very difficult. In addition, this method takes a minimum of 30 min to obtain the zone of hydrolysis after flooding and the hydrolyzed area is not sharply discernible. An improved plate assay is reported herein for the detection of extracellular alginate lyase production by microorganisms. In this method, alginate-containing agar plates are flooded with Gram's iodine instead of CPC. Gram's iodine forms a bluish black complex with alginate but not with hydrolyzed alginate, giving sharp, distinct zones around the alginate lyase producing microbial colonies within 2-3 min. Gram's iodine method was found to be more effective than the CPC method in terms of visualization and measurement of zone size. The alginate-lyase-activity area indicated using the Gram's iodine method was found to be larger than that indicated by the CPC method. Both methods (CPC and Gram's iodine) showed the largest alginate lyase activity area for Saccharophagus degradans (ATCC 43961) followed by Microbulbifer mangrovi (KCTC 23483), Bacillus cereus (KF801505) and Paracoccus sp. LL1 (KP288668) grown on minimal sea salt medium. The rate of growth and metabolite production in alginate-containing minimal sea salt liquid medium, followed trends similar to that of the zone activity areas for the four bacteria under study. These results suggested that the assay developed in this study of Gram's iodine could be useful to predict the potential of microorganisms to produce alginate lyase. The method also

  13. Encapsulation of phycocyanin-alginate for high stability and antioxidant activity

    Science.gov (United States)

    Hadiyanto; Suzery, Meiny; Setyawan, Deny; Majid, Dian; Sutanto, Heri

    2017-02-01

    The aim of this study was to obtain optimal condition of phycocyanin-alginate encapsulation, encapsulation efficiency and phycocyanin load, physicochemical properties of beads, in vitro release study, stability and antioxidant activity. The result product with alginate content 1,5% (w/v) and 2% (w/v) produced were in spherical shape than product with alginate content 2,5% (w/v) by ratio of phycocyanin 1:1. Increasing alginate content on encapsulation process will increase of encapsulation efficiency and phycocyanin load. In vitro released study showed that phycocyanin-alginate beads were more resistant in simulated gastric fluid, while rapidly release in simulated intestinal fluid. The antioxidant activity showed that phycocyanin antioxidant activity decreased after encapsulation process due to duration of storage and the possibility of a cracking which will cause reduced stability of phycocyanin.

  14. Microencapsulation of bioactives in cross-linked alginate matrices by spray drying.

    Science.gov (United States)

    Santa-Maria, Monica; Scher, Herbert; Jeoh, Tina

    2012-01-01

    Microencapsulation of biomolecules, cells and chemicals is widely used in the food and pharmaceutical industries to improve stability, delivery and to control the release of encapsulated moieties. Among encapsulation matrices, alginate is preferred due to its low cost, biodegradability and biocompatibility. Current methods for producing stable alginate gels involve dropping alginate suspensions into divalent cation solutions. This procedure is difficult to scale-up and produces undesirably large alginate beads. In our novel encapsulation method, alginate gelation occurs during spray drying upon volatilisation of a base and rapid release of otherwise unavailable calcium ions. The resulting particles, with median particle sizes in the range 15-120 µm, are insoluble in solution. Cellulase and hemicellulase activities encapsulated by this method were not compromised during spray drying and remained stable over prolonged storage. The procedure described here offers a one-step alternative to other encapsulation methods that are costly and difficult to scale-up.

  15. Bacterial alginate production: an overview of its biosynthesis and potential industrial production.

    Science.gov (United States)

    Urtuvia, Viviana; Maturana, Nataly; Acevedo, Fernando; Peña, Carlos; Díaz-Barrera, Alvaro

    2017-10-07

    Alginate is a linear polysaccharide that can be used for different applications in the food and pharmaceutical industries. These polysaccharides have a chemical structure composed of subunits of (1-4)-β-D-mannuronic acid (M) and its C-5 epimer α-L-guluronic acid (G). The monomer composition and molecular weight of alginates are known to have effects on their properties. Currently, these polysaccharides are commercially extracted from seaweed but can also be produced by Azotobacter vinelandii and Pseudomonas spp. as an extracellular polymer. One strategy to produce alginates with different molecular weights and with reproducible physicochemical characteristics is through the manipulation of the culture conditions during fermentation. This mini-review provides a comparative analysis of the metabolic pathways and molecular mechanisms involved in alginate polymerization from A. vinelandii and Pseudomonas spp. Different fermentation strategies used to produce alginates at a bioreactor laboratory scale are described.

  16. 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

    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 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...... 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...

  17. 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.

  18. 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.

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

    Science.gov (United States)

    Yadav, Mithilesh; Rhee, Kyong Yop

    2012-09-01

    A superabsorbent composite (alginate-g-PAMPS/MMT) was prepared by graft copolymerization from alginate, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and Na+ montmorillonite (MMT) in an inert atmosphere. Effects of polymerization variables on water absorbency, including the content of Na+ montmorillonite, sodium alginate, N,N'-methylenebisacrylamide and AMPS, were studied. The introduced montmorillonite formed a loose and porous surface and improved the water absorbency of the alginate-g-PAMPS/MMT superabsorbent composite. Swelling behaviors of the superabsorbent composites in various cationic salt solutions (NaCl, CaCl2 and FeCl3) and anionic salt solutions (NaCl and Na2SO4) were also systematically investigated. The superabsorbent composite was further characterized using Fourier transform infrared spectroscopy (FTIR), rheology, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) taking alginate-g-PAMPS as a reference. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. 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)

  1. Antifungal Effect of a Dental Tissue Conditioner Containing Nystatin-Loaded Alginate Microparticles.

    Science.gov (United States)

    Kim, Hyun-Jin; Son, Jun Sik; Kwon, Tae-Yub

    2018-02-01

    In this in vitro study, nystatin-alginate microparticles were successfully fabricated to control the release of nystatin from a commercial dental tissue conditioner. These nystatin-alginate microparticles were spherical and had a slightly rough surface. The microparticles incorporated into the tissue conditioner were distributed homogeneously throughout the tissue conditioner matrix. The incorporation of the microparticles did not deteriorate the mechanical properties of the original material. The agar diffusion test results showed that the tissue conditioner containing the microparticles had a good antifungal effect against Candida albicans. The nystatin-alginate microparticles efficiently controlled the release of nystatin from the tissue conditioner matrix over the experimental period of 14 days. Moreover, the nystatin-alginate microparticles incorporated in the tissue conditioner showed effective antifungal function even at lower concentrations of nystatin. The current study suggests that the tissue conditioner containing the nystatin-alginate microparticle carrier system has potential as an effective antifungal material.

  2. 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

    OpenAIRE

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    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 th...

  3. 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

  4. Antifibrotic effect of rapamycin containing polyethylene glycol-coated alginate microcapsule in islet xenotransplantation.

    Science.gov (United States)

    Park, Heon-Seok; Kim, Ji-Won; Lee, Seung-Hwan; Yang, Hae Kyung; Ham, Dong-Sik; Sun, Cheng-Lin; Hong, Tae Ho; Khang, Gilson; Park, Chung-Gyu; Yoon, Kun-Ho

    2017-04-01

    Islet microencapsulation is an attractive strategy for the minimization or avoidance of life-long immunosuppression after transplantation. However, the clinical implementation of this technique is currently limited by incomplete biocompatibility. Thus, the aim of the present study was to demonstrate the improved biocompatibility of rapamycin-containing polyethylene glycol (Rapa-PEG)-coating on alginate microcapsules containing xenogeneic islets. The Rapa-PEG-coating on the alginate layer was observed using scanning electron microscopy (SEM) and the molecular cut-off weight of the microcapsules was approximately 70 kDa. The viabilities of the alginate-encapsulated and Rapa-PEG-coated alginate-encapsulated islets were lower than the viability of the naked islets just after encapsulation, but these the differences diminished over time in culture dishes. Rapa-PEG-coating on the alginate capsules effectively decreased the proliferation of macrophage cells compared to the non-coating and alginate coating of xenogeneic pancreas tissues. Glucose-stimulated insulin secretion did not significantly differ among the groups prior to transplantation. The random blood glucose levels of diabetic mice significantly improved following the transplantation of alginate-encapsulated and Rapa-PEG-coated alginate-encapsulated islets, but there were no significant differences between these two groups. However, there was a significant decrease in the number of microcapsules with fibrotic cell infiltration in the Rapa-PEG-coated alginate microcapsule group compared to the alginate microcapsule group. In conclusion, Rapa-PEG-coating might be an effective technique with which to improve the biocompatibility of microcapsules containing xenogeneic islets. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  5. 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

    2014-03-01

    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. © 2013 Wiley Periodicals, Inc.

  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. Synthesis of "click" alginate hydrogel capsules and comparison of their stability, water swelling, and diffusion properties with that of Ca(+2) crosslinked alginate capsules.

    Science.gov (United States)

    Breger, Joyce C; Fisher, Benjamin; Samy, Raghu; Pollack, Steven; Wang, Nam Sun; Isayeva, Irada

    2015-07-01

    Ionically crosslinked alginate hydrogels have been extensively explored for encapsulation and immunoisolation of living cells/tissues to develop implantable cell therapies, such as islet encapsulation for bioartificial pancreas. Chemical instability of these hydrogels during long-term implantation hinders the development of viable cell therapy. The exchange between divalent crosslinking ions (e.g., Ca(+2) ) with monovalent ions from physiological environment causes alginate hydrogels to degrade, resulting in exposure of the donor tissue to the host's immune system and graft failure. The goal of this study was to improve stability of alginate hydrogels by utilizing covalent "click" crosslinking while preserving other biomedically viable hydrogel properties. Alginate was first functionalized to contain either pendant alkyne or azide functionalities, and subsequently reacted via "click" chemistry to form "click" gel capsules. Alginate functionalization was confirmed by NMR and gel permeation chromatography. When compared with Ca(+2) capsules, "click" capsules exhibited superior stability in ionic media, while showing higher permeability to small size diffusants and similar molecular weight cut-off and water swelling. Physicochemical properties of "click" alginate hydrogels demonstrate their potential utility for therapeutic cell encapsulation and other biomedical applications. © 2014 Wiley Periodicals, Inc.

  8. Self-assembled chitosan-alginate polyplex nanoparticles containing temoporfin

    Czech Academy of Sciences Publication Activity Database

    Brezaniova, I.; Trousil, Jiří; Černochová, Zulfiya; Král, V.; Hrubý, Martin; Štěpánek, Petr; Šlouf, Miroslav

    2017-01-01

    Roč. 295, č. 8 (2017), s. 1259-1270 ISSN 0303-402X R&D Projects: GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109; GA ČR(CZ) GA16-02870S; GA MZd(CZ) NV15-25781A; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : chitosan * sodium alginate * temoporfin Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.723, year: 2016

  9. Calcium alginate gel as encapsulation matrix for coimmobilized enzyme systems.

    Science.gov (United States)

    Blandino, A; Macías, M; Cantero, D

    2003-07-01

    Encapsulation within calcium alginate gel capsules was used to produce a coimmobilized enzyme system. Glucose oxidase (GOD) and catalase (CAT) were chosen as model enzymes. The same values of Vmax and Km app for the GOD encapsulated system and for the GOD-CAT coencapsulated system were calculated. When gel beads and capsules were compared, the same catalyst deactivation sequence for the two enzymes was observed. However, when capsules were employed as immobilization support, GOD efficiencies were higher than for the gel beads. These results were explained in terms of the structure of the capsules.

  10. Comparison of ready-made and self-setting alginate membranes used as a barrier membrane for guided bone regeneration.

    Science.gov (United States)

    Ueyama, Yoshiya; Koyama, Takahiro; Ishikawa, Kunio; Mano, Takamitsu; Ogawa, Yukio; Nagatsuka, Hitoshi; Suzuki, Kazuomi

    2006-03-01

    In order to understand the requirements of guided bone regeneration (GBR) involving alginate base self-setting barrier membranes, GBR was performed in the case of bicortical bone defects formed at the tibiae of experimental animals employing self-setting and ready-made alginate membranes. Connective tissue ingress into the bone defects at the skin side of the tibia was observed when GBR was generated utilizing ready-made alginate membrane. In contrast, bone defects were reconstructed with bone tissue when GBR was generated with self-setting alginate membrane formed from aqueous 3% sodium alginate and 3% CaCl(2) solutions. The unreacted aqueous sodium alginate solution inherent to self-setting alginate membrane did not inhibit bone tissue regeneration. Rather, callus bone was formed using sodium alginate as the nucleus. However, when GBR was effected with self-setting alginate membrane formed from aqueous 10% CaCl(2) solution, membrane was too thick and thus regeneration of bone tissue in the bone cavity was prevented. Therefore, we concluded that self-setting alginate membrane is very useful as a barrier membrane for GBR upon appropriate adjustment of conditions with respect to preparation of alginate membrane.

  11. Restorative dentistry for children.

    Science.gov (United States)

    Donly, Kevin J

    2013-01-01

    This article discusses contemporary pediatric restorative dentistry. Indications and contraindications for the choice of different restorative materials in different clinical situations, including the risk assessment of the patient, are presented. The specific use of glass ionomer cement or resin-modified glass ionomer cement, resin-based composite, and stainless steel crowns is discussed so that preparation design and restoration placement is understood. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Carbon Dioxide Nucleation as a Novel Cleaning Method for Sodium Alginate Fouling Removal from Reverse Osmosis Membranes desalination

    KAUST Repository

    Alnajjar, Heba

    2017-05-01

    The use of Reverse osmosis (RO) membranes have been significantly increasing in water desalination, and the main operational obstacle in RO desalination plants is membrane fouling. Among other solutes, dissolved biopolymers, such as polysaccharides can lead to severe membrane fouling especially with the addition of calcium ions because of the complexation formation between the surface of membrane and foulants materials. However, this complexation can also take place in the feed bulk, resulting in foulants aggregates formation. Although there are some physical techniques that can maintain the membrane performance without reducing its lifetime, only chemical cleanings are still commonly used in RO plants. In this study, a novel cleaning method is proposed to restore the membrane performance by removing the deposited foulants without reducing the membrane lifetime. The cleaning method is based on using water saturated with dissolved CO2 gas, and its principle is based on producing spontaneous CO2 bubbles due to local pressure difference leading to nucleation of bubbles throughout the membrane surface, especially at nucleation sites, which improve the cleaning efficiency. Alginic acid sodium salt was used as a model of polysaccharides foulants in presence of different concentrations of NaCl and calcium ions aiming to enhance membrane fouling, and then CO2 cleaning solution efficiency, in terms flux recovery (FR), was tested under different operating conditions and compared to other cleaning methods. Average FR of 20%±3, 25%±3 and 80%±3 for MilliQ water, a cleaning solution at pH4, and CO2 solution at 6 bar, 0.17 m/s, and 23 ̊C ±0.2 for 6 minutes were obtained, respectively. The efficiency of this novel cleaning method was also compared to direct osmosis overnight, and the average flux was comparable (about 60%±3), though that the cleaning time was significantly different. Various calcium concentrations (0-10 mM) were added in the alginate solution to study the

  13. A comparative study on the raft chemical properties of various alginate antacid raft-forming products.

    Science.gov (United States)

    Dettmar, Peter W; Gil-Gonzalez, Diana; Fisher, Jeanine; Flint, Lucy; Rainforth, Daniel; Moreno-Herrera, Antonio; Potts, Mark

    2018-01-01

    Research to measure the chemical characterization of alginate rafts for good raft performance and ascertain how formulation can affect chemical parameters. A selection of alginate formulations was investigated all claiming to be proficient raft formers with significance between products established and ranked. Procedures were selected which demonstrated the chemical characterization allowing rafts to effectively impede the reflux into the esophagus or in severe cases to be refluxed preferentially into the esophagus and exert a demulcent effect, with focus of current research on methods which complement previous studies centered on physical properties. The alginate content was analyzed by a newly developed HPLC method. Methods were used to determine the neutralization profile and the acid neutralization within the raft determined along with how raft structure affects neutralization. Alginate content of Gaviscon Double Action (GDA) within the raft was significantly superior (p Alginate formulations require three chemical reactions to take place simultaneously: transformation to alginic acid, sodium carbonate reacting to form carbon dioxide, calcium releasing free calcium ions to bind with alginic acid providing strength to raft formation. GDA was significantly superior (p <.0001) to all other comparators.

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

    Science.gov (United States)

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

    2016-01-01

    For quantification of polysaccharides, including heparins and alginates, the commonly used carbazole assay involves hydrolysis of the polysaccharide to form a mixture of UV-active dye conjugate products. Here, we describe two efficient detection and quantification methods that make use of the negative charges of the alginate polymer and do not involve degradation of the targeted polysaccharide. The first method utilizes calcium ions to induce formation of hydrogel-like aggregates with alginate polymer; the aggregates can be quantified readily by staining with a crystal violet dye. This method does not require purification of alginate from the culture medium and can measure the large amount of alginate that is produced by a mucoid Pseudomonas aeruginosa culture. The second method employs polycations tethering a fluorescent dye to form suspension aggregates with the alginate polyanion. Encasing the fluorescent dye in the aggregates provides an increased scattering intensity with a sensitivity comparable to that of the conventional carbazole assay. Both approaches provide efficient methods for monitoring alginate production by mucoid P. aeruginosa. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. 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.

  16. Dodecenyl succinylated alginate as a novel material for encapsulation and hyperactivation of lipases.

    Science.gov (United States)

    Falkeborg, Mia; Paitaid, Pattarapon; Shu, Allen Ndonwi; Pérez, Bianca; Guo, Zheng

    2015-11-20

    Alginate was modified with dodecenyl succinic anhydride (SAC12) in an aqueous reaction medium at neutral pH. The highest degree of succinylation (33.9±3.5%) was obtained after 4h at 30°C, using four mole SAC12 per mol alginate monomer. Alginate was modified with succinic anhydride (SAC0) for comparison, and the structures and thermal properties of alg-SAC0 and alg-SAC12 were evaluated using FTIR, (1)H NMR, and DSC. Calcium-hydrogel beads were formed from native and modified alginates, in which lipases were encapsulated with a load of averagely 76μg lipase per mg alginate, irrespective of the type of alginate. Lipases with a "lid", which usually are dependent on interfacial activation, showed a 3-fold increase in specific activity toward water-soluble substrates when encapsulated in alg-SAC12, compared to the free lipase. Such hyperactivation was not observed for lipases independent of interfacial activation, or for lipases encapsulated in native alginate or alg-SAC0 hydrogels. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  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. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Encapsulation of Lactobacillus kefiri in alginate microbeads using a double novel aerosol technique.

    Science.gov (United States)

    Demitri, Christian; Lamanna, Leonardo; De Benedetto, Egidio; Damiano, Fabrizio; Cappello, Maria Stella; Siculella, Luisa; Sannino, Alessandro

    2017-08-01

    Alginate micro beads containing Lactobacillus kefiri (the principal bacteria present in the kefir probiotic drink) were produced by a novel technique based on dual aerosols spaying of alginate based solution and CaCl2 as cross linking agent. Carboxymethylcellulose (CMC) has been also added to the alginate in order to change the physic-chemical properties (viscosity and permeability) of the microbeads. Calcium alginate and CMC are biopolymers that can be used for developing oral drug-delivery systems. These biopolymers have been reported to show a pH-dependent swelling behaviour. Calcium alginate and CMC have also been known to possess an excellent mucoadhesive property. The loaded microbeads have been characterized in terms of morphology, chemical composition and stability in different conditions mimicking the gastric environment. In this study, we demonstrate the feasibility of a continuous fabrication of alginate microbeads in a range of 50-70μm size, encapsulating L. kefiri as active ingredient. The technique involves the use of a double aerosols of alginate based solution and CaCl2 as crosslinking agent. Moreover, the encapsulation process was proved to be effective and not detrimental to bacteria viability. At the same time, it was verified the protective efficacy of the microcapsules against the gastric environment using both SGF pH1.2 (fasted state) and pH2.2 (feed state). Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Synthesis of multilayered alginate microcapsules for the sustained release of fibroblast growth factor-1

    Science.gov (United States)

    Khanna, Omaditya; Moya, Monica L; Opara, Emmanuel C; Brey, Eric M

    2010-01-01

    Alginate microcapsules coated with a permselective poly-L-ornithine (PLO) membrane have been investigated for the encapsulation and transplantation of islets as a treatment for type 1 diabetes. The therapeutic potential of this approach could be improved through local stimulation of microvascular networks in order to meet mass transport demands of the encapsulated cells. Fibroblast growth factor-1 (FGF-1) is a potent angiogenic factor with optimal effect occurring when it is delivered in a sustained manner. In this paper, a technique is described for the generation of multilayered alginate microcapsules with an outer alginate layer that can be used for the delivery of FGF-1. The influence of alginate concentration and composition (high mannuronic acid (M) or guluronic acid (G) content) on outer layer size and stability, protein encapsulation efficiency, and release kinetics was investigated. The technique results in a stable outer layer of alginate with a mean thickness between 113–164 µm, increasing with alginate concentration and G-content. The outer layer was able to encapsulate and release FGF-1 for up to thirty days, with 1.25% of high G alginate displaying the most sustained release. The released FGF-1 retained its biologic activity in the presence of heparin, and the addition of the outer layer did not alter the permselectivity of the PLO coat. This technique could be used to generate encapsulation systems that deliver proteins to stimulate local neovascularization around encapsulated islets. PMID:20725969

  1. Effect of Sodium Alginate Addition to Resveratrol on Acute Gouty Arthritis

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2015-04-01

    Full Text Available Objective: Resveratrol has been shown to exert anti-inflammatory and antioxidant effects, while sodium alginate is a common pharmaceutic adjuvant with antioxidative and immunomodulatory properties. We performed an animal study to investigate the effect of sodium alginate addition to resveratrol on acute gouty arthritis. Methods: Twenty-four SPF Wistar mice were randomized to four groups receiving the combination of sodium alginate and resveratrol, resveratrol alone, colchicine, and placebo, respectively. Acute gouty arthritis was induced by injection of 0.05 ml monosodium urate (MSU solution (25g/mL into ankle joint cavity. IL-1β, CCR5, and CXCL10 levels in both serum and synovial fluid were measured using ELISA. NLRP3 expression in the synovial tissues was measured using western plot. Results: The combination of sodium alginate and resveratrol significantly reduced synovial levels of IL-1β, CCR5, and CXCL10 when compared with colchicines, and all P values were less than 0.0001. The combination of sodium alginate and resveratrol was also superior to resveratrol in terms of both serum levels and synovial levels of IL-1β, CCR5, and CXCL10. In addition, resveratrol, with or without sodium alginate, could reduce NLRP3 expression obviously in the synovial tissues. Conclusion: The combination of sodium alginate and resveratrol has better effect over colchicines in treating MSU-induced acute gouty arthritis.

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

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    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.

  3. Colloid properties of hydrophobic modified alginate: Surface tension, ζ-potential, viscosity and emulsification.

    Science.gov (United States)

    Wu, Zongmei; Wu, Jie; Zhang, Ruling; Yuan, Shichao; Lu, Qingliang; Yu, Yueqin

    2018-02-01

    Micelle properties of hydrophobic modified alginate (HM-alginate) in various dispersion media have been studied by surface tension, ζ-potential, and viscosity measurements. Effect of salt on micelle properties showed that the presence of counter ion weakened the repulsive interaction between surfactant ions, decreased the critical micelle concentration (CMC) value of the HM-alginate, reduced the effective volume dimensions of HM-alginate and hence viscosity, which coincide with the corresponding ζ-potential values. Soy oil-in-water emulsions, stabilized solely by HM-alginate, were produced in high speed homogenization conditions and their stability properties were studied by visual inspection, optical microscopy and droplet size measurements. The results showed that emulsions (oil-water ratio was 1:7) containing 15mg/mL HM-alginate presented better stability during 15days storage, which stating clearly that HM-alginate is an effective emulsifier to stabilize oil-in-water emulsions. The herein presented homogeneous method for preparation of emulsion has the potential to be used in food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Processing-Size Correlations in the Preparation of Magnetic Alginate Microspheres Through Emulsification and Ionic Crosslinking.

    Science.gov (United States)

    Garcia, Andrew R; Lacko, Christopher; Snyder, Catherine; Bohórquez, Ana C; Schmidt, Christine E; Rinaldi, Carlos

    2017-09-20

    Magnetic alginate microspheres are biocompatible due to their alginate matrix, and motion-controllable by applied magnetic fields due to their magnetic character. Therefore, they have the potential of being used as vessels to a broad variety of materials, including drugs and therapeutic agents, facilitating entry to biological systems in a relatively non-invasive manner. Here, magnetic alginate microspheres were prepared through an emulsification and ionic cross-linking process, where a mixture of alginate and iron oxide magnetic nanoparticles was initially dispersed in a continuous phase, followed by gelation of this dispersed phase into microspheres by cross-linking the dispersion with calcium ions. The resulting magnetic alginate microspheres were found to be superparamagnetic and to respond to applied magnetic fields by chain formation. The effect of shear rate, alginate concentration, and magnetic nanoparticle concentration on microsphere size was investigated with the aim to control the size of microspheres with respect to process and formulation parameters. Two of these parameters, shear rate and alginate concentration, were used to correlate experimental results with a theoretical model for the case where the dispersed phase is more viscous than the continuous phase.

  5. Novel biomimetic hydroxyapatite/alginate nanocomposite fibrous scaffolds for bone tissue regeneration.

    Science.gov (United States)

    Chae, Taesik; Yang, Heejae; Leung, Victor; Ko, Frank; Troczynski, Tom

    2013-08-01

    Hydroxyapatite/alginate nanocomposite fibrous scaffolds were fabricated via electrospinning and a novel in situ synthesis of hydroxyapatite (HAp) that mimics mineralized collagen fibrils in bone tissue. Poorly crystalline HAp nanocrystals, as confirmed by X-ray diffractometer peak approximately at 2θ = 32° and Fourier transform infrared spectroscopy spectrum with double split bands of PO4(v 4) at 564 and 602 cm(-1), were induced to nucleate and grow at the [-COO(-)]-Ca(2+)-[-COO(-)] linkage sites on electrospun alginate nanofibers impregnated with PO4 (3-) ions. This novel process resulted in a uniform deposition of HAp nanocrystals on the nanofibers, overcoming the severe agglomeration of HAp nanoparticles processed by the conventional mechanical blending/electrospinning method. Preliminary in vitro cell study showed that rat calvarial osteoblasts attached more stably on the surface of the HAp/alginate scaffolds than on the pure alginate scaffold. In general, the osteoblasts were stretched and elongated into a spindle-shape on the HAp/alginate scaffolds, whereas the cells had a round-shaped morphology on the alginate scaffold. The unique nanofibrous topography combined with the hybridization of HAp and alginate can be advantageous in bone tissue regenerative medicine applications.

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

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    Jovanović Željka

    2012-01-01

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

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

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    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.

  8. Hybrid 3D printing and electrodeposition approach for controllable 3D alginate hydrogel formation.

    Science.gov (United States)

    Shang, Wanfeng; Liu, Yanting; Wan, Wenfeng; Hu, Chengzhi; Liu, Zeyang; Wong, Chin To; Fukuda, Toshio; Shen, Yajing

    2017-06-07

    Calcium alginate hydrogels are widely used as biocompatible materials in a substantial number of biomedical applications. This paper reports on a hybrid 3D printing and electrodeposition approach for forming 3D calcium alginate hydrogels in a controllable manner. Firstly, a specific 3D hydrogel printing system is developed by integrating a customized ejection syringe with a conventional 3D printer. Then, a mixed solution of sodium alginate and CaCO3 nanoparticles is filled into the syringe and can be continuously ejected out of the syringe nozzle onto a conductive substrate. When applying a DC voltage (∼5 V) between the substrate (anode) and the nozzle (cathode), the Ca(2+) released from the CaCO3 particles can crosslink the alginate to form calcium alginate hydrogel on the substrate. To elucidate the gel formation mechanism and better control the gel growth, we can further establish and verify a gel growth model by considering several key parameters, i.e., applied voltage and deposition time. The experimental results indicate that the alginate hydrogel of various 3D structures can be formed by controlling the movement of the 3D printer. A cell viability test is conducted and shows that the encapsulated cells in the gel can maintain a high survival rate (∼99% right after gel formation). This research establishes a reliable method for the controllable formation of 3D calcium alginate hydrogel, exhibiting great potential for use in basic biology and applied biomedical engineering.

  9. Magnetic Pycnoporus sanguineus-Loaded Alginate Composite Beads for Removing Dye from Aqueous Solutions

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    Chih-Hui Yang

    2014-06-01

    Full Text Available Dye pollution in wastewater is a severe environmental problem because treating water containing dyes using conventional physical, chemical, and biological treatments is difficult. A conventional process is used to adsorb dyes and filter wastewater. Magnetic filtration is an emerging technology. In this study, magnetic Pycnoporus sanguineus-loaded alginate composite beads were employed to remove a dye solution. A white rot fungus, P. sanguineus, immobilized in alginate beads were used as a biosorbent to remove the dye solution. An alginate polymer could protect P. sanguineus in acidic environments. Superparamagnetic nanomaterials, iron oxide nanoparticles, were combined with alginate gels to form magnetic alginate composites. The magnetic guidability of alginate composites and biocompatibility of iron oxide nanoparticles facilitated the magnetic filtration and separation processes. The fungus cells were immobilized in loaded alginate composites to study the influence of the initial dye concentration and pH on the biosorption capacity. The composite beads could be removed easily post-adsorption by using a magnetic filtration process. When the amount of composite beads was varied, the results of kinetic studies of malachite green adsorption by immobilized cells of P. sanguineus fitted well with the pseudo-second-order model. The results indicated that the magnetic composite beads effectively adsorbed the dye solution from wastewater and were environmentally friendly.

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

    Science.gov (United States)

    Horniblow, Richard D; Dowle, Miriam; Iqbal, Tariq H; Latunde-Dada, Gladys O; Palmer, Richard E; Pikramenou, Zoe; Tselepis, Chris

    2015-01-01

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

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

    Science.gov (United States)

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

    2014-05-01

    Terminal, or postprocessing, sterilization of composite biomaterials is crucial for their use in wound healing and tissue-engineered devices. Recent research has focused on optimizing traditional biomaterial formulations to create better products for commercial and academic use which incorporate hydrophobic compounds or secondary gel networks. To use a hydrogel in a clinical setting, terminal sterilization is necessary to ensure patient safety. Lyophilization, gamma-irradiation, and ethylene oxide treatment all have negative consequences when applied to alginate scaffolds for clinical use. Here, we aim to find alternative terminal sterilization methods for alginate and alginate-based composite hydrogels which maintain the structure of composite alginate networks for use in biomedical applications. A thorough investigation of the effect of common sterilization methods on swollen alginate-based hydrogels has not been reported and therefore, this work examines autoclaving, ethanol washing, and ultraviolet light as sterilization techniques for alginate and alginate/Pluronic® F68 composite hydrogels. Preservation of structural integrity is evaluated using shear rheology and analysis of water retention, and efficacy of sterilization is determined via bacterial persistence within the hydrogel. Results indicate that ethanol sterilization is the best method of those investigated because ethanol washing results in minimal effects on mechanical properties and water retention and eliminates bacterial persistence. Furthermore, this study suggests that ethanol treatment is an efficacious method for terminally sterilizing interpenetrating networks or other composite hydrogel systems. Copyright © 2013 Wiley Periodicals, Inc.

  12. Enhanced stability and mechanical strength of sodium alginate composite films.

    Science.gov (United States)

    Liu, Sijun; Li, Yong; Li, Lin

    2017-03-15

    This work aims to study how three kinds of nanofillers: graphene oxide (GO), ammonia functionalized graphene oxide (AGO), and triethoxylpropylaminosilane functionalized silica, can affect stability and mechanical strength of sodium alginate (SA) composite films. The filler/sodium alginate (SA) solutions were first studied by rheology to reveal effects of various fillers on zero shear viscosity η0. SA composite films were then prepared by a solution mixing-evaporation method. The structure, morphology and properties of SA composite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), contact angle and mechanical testing. Compared to GO and silica, the presence of AGO significantly improved the interaction between AGO and SA, which led to the increase in stability and mechanical strength of the resulting SA composite films. The tensile strength and elongation at break of AGO/SA composite film at 3wt% AGO loading were increased by 114.9% and 194.4%, respectively, in contrast to pure SA film. Furthermore, the stability of AGO/SA composite films at high temperatures and in a wet environment were better than that of silica/SA and GO/SA composite films. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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    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.

  14. Alginate encapsulated nanoparticle-microorganism system for trichloroethylene remediation

    Science.gov (United States)

    Shanbhogue, Sai Sharanya

    Nanoscale zero-valent iron (NZVI) particles were encapsulated in calcium alginate capsules for application in environmental remediation. TCE degradation rates for encapsulated and bare NZVI were similar indicating no adverse effects of encapsulation on degradation kinetics. Microorganisms were separately encapsulated and used along with encapsulated NZVI and co-encapsulated in calcium alginate capsules. Batch experiments were performed to test the efficacy of the combined iron-Pseudomonas sp. (PpF1) system. The combined system removed 100% TCE over the first three hours of the experiment followed by 70% TCE removal post TCE re-dosing. Complete reduction of TCE was achieved by NZVI between 0--3 h and the second phase of treatment (3--36 h) was mostly achieved by microorganisms. Experiments conducted with co-encapsulated NZVI-D.BAV1 achieved 100% TCE removal. During the first three hours of the experiment 100% TCE removal was achieved by NZVI, and 100% removal was achieved post re-dosing where D.BAV1 accomplished the treatment.

  15. Immobilization of Glucose Oxidase in Alginate-Chitosan Microcapsules

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    Xia Wang

    2011-05-01

    Full Text Available In order to improve its stability and catalytic rate in flour, the immobilization of glucose oxidase (GOX was investigated in this work. The enzyme was encapsulated in calcium alginate-chitosan microspheres (CACM using an emulsification-internal gelation-GOX adsorption‑chitosan coating method. The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR. The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM, was spherical with a mean diameter of about 26 μm. The GOX load, encapsulation efficiency and activity of the CACM-GOX were influenced by concentration of chitosan, encapsulation time and encapsulation pH. The highest total enzymatic activity and encapsulation efficiency was achieved when the pH of the adsorption medium was near the isoelectric point (pI of GOX, approximately pH 4.0. In addition, the molecular weight of chitosan also evidently influenced the encapsulation efficiency. Storage stabilities of GOX samples were investigated continuously over two months and the retained activity of CACM-GOX was 70.4%, markedly higher than the 7.5% of free enzyme. The results reveal the great potential of CACM-GOX as a flour improver.

  16. GOLD NANOPARTICLES ENCAPSULATED IN A POLYMERIC MATRIX OF SODIUM ALGINATE

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    Oana Lelia POP

    2016-11-01

    Full Text Available Plasmonic nanoparticles can be used as building blocks for the design of multifunctional systems based on polymeric capsules. The use of functionalised particles in therapeutics and imaging and understanding their effect on the cell functions are among the current challenges in nanobiotechnology and nanomedicine. The aim of the study was to manufacture and characterize polymeric microstructures by encapsulating plasmonic gold nanoparticles in biocompatible matrix of sodium alginate. The gold nanoparticles were obtained by reduction of tetracluoroauric acid with sodium citrate. To characterize the microcapsules, UV-Vis and FTIR spectroscopy, optical and confocal microscopy experiments were performed. In vitro cytotoxicity tests on HFL-1 cells were also performed. The capsules have spherical shape and 120 μm diameter. The presence of encapsulated gold nanoparticles is also shown by confocal microscopy. In vitro tests show that the microcapsules are not cytotoxic upon 24 h of cells exposure to microcapsules concentrations ranging from 2.5 to 25 capsules per cell. The obtained microcapsules of sodium alginate loaded with plasmonic gold nanoparticles could potentially be considered as release systems for biologically relevant molecules.

  17. Performance and biocompatibility of extremely tough alginate/polyacrylamide hydrogels.

    Science.gov (United States)

    Darnell, Max C; Sun, Jeong-Yun; Mehta, Manav; Johnson, Christopher; Arany, Praveen R; Suo, Zhigang; Mooney, David J

    2013-11-01

    Although hydrogels now see widespread use in a host of applications, low fracture toughness and brittleness have limited their more broad use. As a recently described interpenetrating network (IPN) of alginate and polyacrylamide demonstrated a fracture toughness of ≈ 9000 J/m(2), we sought to explore the biocompatibility and maintenance of mechanical properties of these hydrogels in cell culture and in vivo conditions. These hydrogels can sustain a compressive strain of over 90% with minimal loss of Young's Modulus as well as minimal swelling for up to 50 days of soaking in culture conditions. Mouse mesenchymal stem cells exposed to the IPN gel-conditioned media maintain high viability, and although cells exposed to conditioned media demonstrate slight reductions in proliferation and metabolic activity (WST assay), these effects are abrogated in a dose-dependent manner. Implantation of these IPN hydrogels into subcutaneous tissue of rats for 8 weeks led to mild fibrotic encapsulation and minimal inflammatory response. These results suggest the further exploration of extremely tough alginate/PAAM IPN hydrogels as biomaterials. © 2013 Elsevier Ltd. All rights reserved.

  18. 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.

  19. Cholesterol-Lowering Effect of Calcium Alginate in Rats.

    Science.gov (United States)

    Idota, Yoko; Kogure, Yumi; Kato, Takako; Ogawa, Mana; Kobayashi, Shoko; Kakinuma, Chihaya; Yano, Kentaro; Arakawa, Hiroshi; Miyajima, Chihiro; Kasahara, Fumiyoshi; Ogihara, Takuo

    2016-01-01

    We examined whether calcium alginate (Ca-Alg) reduces blood cholesterol levels in rats fed a high-cholesterol diet. First, we examined taurocholate adsorption in vitro by various types of sodium alginate (Na-Alg). High molecular-weight, guluronic acid-rich Na-Alg showed the greatest adsorption of taurocholate, and therefore the corresponding Ca-Alg was chosen for the in vivo study. Rats were fed a high-cholesterol diet or a Ca-Alg-containing diet for 2 weeks. Body weight and diet intake were measured, and the general condition of the animals was monitored during this period. After 14 d, the plasma concentration of cholesterol, portal plasma concentration of bile acid, and bile acid in feces were measured. The plasma concentration of cholesterol was significantly reduced in rats fed a 2% Ca-Alg-containing diet. Furthermore, the portal concentration of bile acid was significantly lowered in the 2% Ca-Alg group. A tendency for a Ca-Alg concentration-dependent increase in fecal excretion of bile acid was also seen, although it was not statistically significant. While several changes in biochemical parameters and histopathological findings were observed, all the values remained within the physiological range. These results indicate that Ca-Alg is effective in reducing plasma cholesterol. A possible mechanism would be enhanced fecal excretion of bile acid due to reduced intestinal reabsorption, which in turn might stimulate bile acid synthesis from cholesterol in the liver, leading to a decrease in plasma cholesterol.

  20. Cartilage regeneration using biodegradable oxidized alginate/hyaluronate hydrogels.

    Science.gov (United States)

    Park, Honghyun; Lee, Kuen Yong

    2014-12-01

    Despite the widespread use of alginate (AL) hydrogels in many biomedical applications, including tissue engineering, AL is inherently non-degradable under physiological conditions. We hypothesized that degradable alginate (dAL) would be useful for cartilage regeneration when combined with hyaluronate (HA). We prepared dAL by partial oxidation of AL using sodium periodate, and the degradation rate of AL hydrogel was able to be regulated by control of sodium periodate concentration. The degradable oxidized AL/HA gels were formed in the presence of cells and their characteristics were investigated. dAL/HA gels with primary chondrocytes were injected subcutaneously into mice. Effective cartilage regeneration was observed after 6 weeks of transplantation based on histological analysis. Moreover, substantial secretion of sulfated glycosaminoglycans and expression of chondrogenic marker genes were also observed compared with non-dAL/HA gels. These results indicate that dAL/HA hydrogels may be useful in cartilage regeneration, and in many tissue engineering applications. © 2014 Wiley Periodicals, Inc.

  1. Formulation design, preparation and characterization of multifunctional alginate stabilized nanodroplets.

    Science.gov (United States)

    Baghbani, Fatemeh; Moztarzadeh, Fathollah; Mohandesi, Jamshid Aghazadeh; Yazdian, Fatemeh; Mokhtari-Dizaji, Manijhe; Hamedi, Sepideh

    2016-08-01

    In the present study the effect of process (homogenization speed) and formulation (polymer-alginate-concentration, surfactant concentration, drug amount, perfluorohexane volume fraction and co-surfactant inclusion) variables on particle size, entrapment efficiency, and drug release kinetics of doxorubicin-loaded alginate stabilized perfluorohexane nanodroplets were evaluated. Particle size and doxorubicin entrapment efficiency were highly affected by formulation and process variables. Increase in homogenization speed resulted in significant decrease in particle size and increase in entrapment efficiency. Polymer concentration and perfluorohexane amount both had similar effect on particle size. Particle size increased by an increase in the amount of both. Entrapment efficiency increased by increasing polymer concentration. In case of surfactant concentration and drug amount, particle size and entrapment efficiency had optimum values and an increase in concentration of both of them behind a certain limit resulted in increase in particle size and decrease in doxorubicin entrapment. In vitro release profile of doxorubicin was an apparently biphasic release process and 7%-13% of drug released after 24h incubation in PBS, pH=7.4, depending on the nanodroplets composition but ultrasound exposure for 10min resulted in triggered release of 85.95% of doxorubicin from optimal formulation (formulation E1 with 39.2nm diameter size and 92.2% entrapment efficiency). Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Physicochemical Characterization of Alginate Beads Containing Sugars and Biopolymers

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    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.

  3. Crystal phase of fibrous calcium phosphates prepared with sodium alginate.

    Science.gov (United States)

    Hayashizaki, J; Ban, S; Arimoto, N; Kato, N; Kimura, Y; Hasegawa, J

    1995-12-01

    This study investigated the effects of preparation conditions on the crystal phase of the fired fiber prepared with sodium alginate. Hydroxyapatite, Ca10(PO4)6(OH)2, hereafter referred to as HA, was only formed in fiber fired at 900 degrees C under proper conditions. There was no significant difference in the crystal phase of the fired fibers prepared using different sodium alginate concentrations and syringe nozzle diameter, although fiber diameters were enlarged with increasing in either. No effects of phosphate type on the crystal phase of the fired fiber were found, but the aging time and the rinsing time had great effects. Sodium calcium phosphate, NaCaPO4, and HA were formed when the aging time was shorter than 5 min. Chlorapatite, Ca5Cl(PO4)3, and HA were formed when the rinsing time was shorter than 3 sec, and HA was formed when the rinsing time was 5 min to 1 hour, beta-TCP, beta-Ca3 (PO4)2, and HA were formed when the rinsing time exceeded 2 weeks.

  4. Analysis of filler particle levels and sizes in dental alginates

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    Hugo Lemes Carlo

    2010-06-01

    Full Text Available The aim of this study was to determine the inorganic filler fractions and sizes of commercially alginates. The inorganic particles volumetric fractions of five alginates - Jeltrate(J, Jeltrate Plus(JP, Jeltrate Chromatic Ortho(JC, Hydrogum(H and Ezact Krom(E were accessed by weighing a previously determined mass of each material in water before and after burning samples at 450 °C for 3 hours. Unsettled materials were soaked in acetone and chloroform and sputter-coated with gold for SEM evaluation of fillers' morphology and size. The results for the volumetric inorganic particle content were (%: J - 48.33, JP - 48.33, JC - 33.79, H - 37.55 and E - 40.55. The fillers presented a circular appearance with helical form and various perforations. Hydrogum fillers looked like cylindrical, perforated sticks. The mean values for fillers size were (μm: J - 12.91, JP - 13.67, JC - 13.44, E - 14.59 and H - 9 (diameter, 8.81 (length. The results of this study revealed differences in filler characteristics that could lead to different results when testing mechanical properties.

  5. 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.

  6. Fabrication and magnetic control of alginate-based rolling microrobots

    Directory of Open Access Journals (Sweden)

    Jamel Ali

    2016-12-01

    Full Text Available Advances in microrobotics for biological applications are often limited due to their complex manufacturing processes, which often utilize cytotoxic materials, as well as limitations in the ability to manipulate these small devices wirelessly. In an effort to overcome these challenges, we investigated a facile method for generating biocompatible hydrogel based robots that are capable of being manipulated using an externally generated magnetic field. Here, we experimentally demonstrate the fabrication and autonomous control of loaded-alginate microspheres, which we term artificial cells. In order to generate these microparticles, we employed a centrifuge-based method in which microspheres were rapidly ejected from a nozzle tip. Specifically, we used two mixtures of sodium alginate; one containing iron oxide nanoparticles and the other containing mammalian cells. This mixture was loaded into a needle that was fixed on top of a microtube containing calcium chloride, and then briefly centrifuged to generate hundreds of Janus microspheres. The fabricated microparticles were then magnetically actuated with a rotating magnetic field, generated using electromagnetic coils, prompting the particles to roll across a glass substrate. Also, using vision-based feedback control, a single artificial cell was manipulated to autonomously move in a programmed pattern.

  7. Oral vaccination of animals with antigens encapsulated in alginate microspheres.

    Science.gov (United States)

    Bowersock, T L; HogenEsch, H; Suckow, M; Guimond, P; Martin, S; Borie, D; Torregrosa, S; Park, H; Park, K

    1999-03-26

    Most infectious diseases begin at a mucosal surface. Prevention of infection must therefore consider ways to enhance local immunity to prevent the attachment and invasion of microbes. Despite this understanding, most vaccines depend on parenterally administered vaccines that induce a circulating immune response that often does not cross to mucosal sites. Administration of vaccines to mucosal sites induces local immunity. To be effective requires that antigen be administered often. This is not always practical depending on the site where protection is needed, nor comfortable to the patient. Not all mucosal sites have inductive lymphoid tissue present as well. Oral administration is easy to do, is well accepted by humans and animals and targets the largest inductive lymphoid tissue in the body in the intestine. Oral administration of antigen requires protection of antigen from the enzymes and pH of the stomach. Polymeric delivery systems are under investigation to deliver vaccines to the intestine while protecting them from adverse conditions that could adversely affect the antigens. They also can enhance delivery of antigen specifically to the inductive lymphoid tissue. Sodium alginate is a readily available, inexpensive polymer that can be used to encapsulate a wide variety of antigens under mild conditions. Orally administered alginate microspheres containing antigen have successfully induced immunity in mice to enteric (rotavirus) pathogens and in the respiratory tract in cattle with a model antigen (ovalbumin). This delivery system offers a safe, effective means of orally vaccinating large numbers of animals (and perhaps humans) to a variety of infectious agents.

  8. Alginate/chitosan nanoparticles are effective for oral insulin delivery.

    Science.gov (United States)

    Sarmento, B; Ribeiro, A; Veiga, F; Sampaio, P; Neufeld, R; Ferreira, D

    2007-12-01

    To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats. Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by confocal microscopy. Nanoparticles were negatively charged and had a mean size of 750 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. The insulin association efficiency was over 70% and insulin was released in a pH-dependent manner under simulated gastrointestinal conditions. Orally delivered nanoparticles lowered basal serum glucose levels by more than 40% with 50 and 100 IU/kg doses sustaining hypoglycemia for over 18 h. Pharmacological availability was 6.8 and 3.4% for the 50 and 100 IU/kg doses respectively, a significant increase over 1.6%, determined for oral insulin alone in solution and over other related studies at the same dose levels. Confocal microscopic examinations of FITC-labelled insulin nanoparticles showed clear adhesion to rat intestinal epithelium, and internalization of insulin within the intestinal mucosa. The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity.

  9. 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.

  10. Evolution of Sulfobacillus thermosulfidooxidans secreting alginate during bioleaching of chalcopyrite concentrate.

    Science.gov (United States)

    Yu, R-L; Liu, A; Liu, Y; Yu, Z; Peng, T; Wu, X; Shen, L; Liu, Y; Li, J; Liu, X; Qiu, G; Chen, M; Zeng, W

    2017-06-01

    To explore the distribution disciplinarian of alginate on the chalcopyrite concentrate surface during bioleaching. The evolution of Sulfobacillus thermosulfidooxidans secreting alginate during bioleaching of chalcopyrite concentrate was investigated through gas chromatography coupled with mass spectrometry (GC-MS) and confocal laser scanning microscope (CLSM), and the critical synthetic genes (algA, algC, algD) of alginate were analysed by real-time polymerase chain reaction (RT-PCR). The GC-MS analysis results indicated that there was a little amount of alginate formed on the mineral surface at the early stage, while increasing largely to the maximum value at the intermediate stage, and then kept a stable value at the end stage. The CLSM analysis of chalcopyrite slice showed the same variation trend of alginate content on the mineral surface. Furthermore, the RT-PCR results showed that during the early stage of bioleaching, the expressions of the algA, algC and the algD genes were all overexpressed. However, at the final stage, the algD gene expression decreased in a large scale, and the algA and algC decreased slightly. This expression pattern was attributed to the fact that algA and algC genes were involved in several biosynthesis reactions, but the algD gene only participated in the alginate biosynthesis and this was considered as the key gene to control alginate synthesis. The content of alginate on the mineral surface increased largely at the beginning of bioleaching, and remained stable at the end of bioleaching due to the restriction of algD gene expression. Our findings provide valuable information to explore the relationship between alginate formation and bioleaching of chalcopyrite. © 2017 The Society for Applied Microbiology.

  11. Injectable MMP-sensitive alginate hydrogels as hMSC delivery systems

    Science.gov (United States)

    Fonseca, Keila B.; Gomes, David B.; Lee, Kangwon; Santos, Susana G.; Sousa, Aureliana; Silva, Eduardo A.; Mooney, David J.; Granja, Pedro L.; Barrias, Cristina C.

    2014-01-01

    Hydrogels with the potential to provide minimally invasive cell delivery represent a powerful tool for tissue-regeneration therapies. In this context, entrapped cells should be able to escape the matrix becoming more available to actively participate in the healing process. Here, we analyzed the performance of proteolytically-degradable alginate hydrogels as vehicles for human mesenchymal stem cells (hMSC) transplantation. Alginate was modified with the matrix metalloproteinase (MMP)-sensitive peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG), which did not promote dendritic cell maturation in vitro, neither free nor conjugated to alginate chains, indicating low immunogenicity. hMSC were entrapped within MMP-sensitive and MMP-insensitive alginate hydrogels, both containing cell-adhesion RGD peptides. Softer (2 wt% alginate) and stiffer (4 wt% alginate) matrices were tested. When embedded in a Matrigel™ layer, hMSC-laden MMP-sensitive alginate hydrogels promoted more extensive outward cell migration and invasion into the tissue mimic. In vivo, after 4 weeks of subcutaneous implantation in a xenograft mouse model, hMSC-laden MMP-sensitive alginate hydrogels showed higher degradation and host tissue invasion than their MMP-insensitive equivalents. In both cases, softer matrices degraded faster than stiffer ones. The transplanted hMSC were able to produce their own collagenous extracellular matrix, and were located not only inside the hydrogels, but also outside, integrated in the host tissue. In summary, injectable MMP-sensitive alginate hydrogels can act as localized depots of cells, and confer protection to transplanted cells while facilitating tissue regeneration. PMID:24345197

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

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, M.; Meenakshisundaram, N.; Rajendran, V., E-mail: veerajendran@gmail.com

    2011-05-15

    In this study, a novel method was used to produce a nanostructured composite consisting of hydroxyapatite and sodium alginate by varying the composition of sodium alginate. The structure, morphology, simulated body fluid response and mechanical properties of the synthesised nanocomposites were characterised. From X-ray diffraction analysis, an increase in crystallite size and degree of crystallinity with an increase in the composition of sodium alginate up to 1.5 wt.% was observed. Further, it was found to decrease with an increase in the composition of sodium alginate. A notable peak shift from 1635 to 1607 cm{sup -1} and 1456 to 1418 cm{sup -1} in the Fourier transform infrared spectra of the nanocomposite was observed towards the lower wave number side when compared with pure hydroxyapatite. It reveals a strong interaction between the positively charged calcium (Ca{sup 2+}) and the negatively charged carboxyl group (COO{sup -}) in sodium alginate. Transmission electron microscopy images of pure hydroxyapatite showed a short nanorod-like morphology with an average particle size of 13 nm. Bioresorbability of the samples was observed by immersing them in simulated body fluid medium for 14 days to evaluate the changes in pH and Ca{sup 2+} ion strength. Microhardness shows an increasing trend with an increase in the composition of sodium alginate from 1.5 to 3.0 wt.%, which is similar to that in the density. - Research Highlights: {yields} We have prepared nanohydroxyapatite/sodium alginate as a composite. {yields} Effect of sodium alginate on the properties of nanohydrroxyapatite has been studied. {yields} The sodium alginate ranges from 0 to 3.75 wt.% has been used. {yields} Composites show improved biological and mechanical properties.

  13. Evaluation of outgassing, tear strength, and detail reproduction in alginate substitute materials.

    Science.gov (United States)

    Baxter, R T; Lawson, N C; Cakir, D; Beck, P; Ramp, L C; Burgess, J O

    2012-01-01

    To compare three alginate substitute materials to an alginate impression material for cast surface porosity (outgassing), tear strength, and detail reproduction. Detail reproduction tests were performed following American National Standards Institute/American Dental Association (ANSI/ADA) Specification No. 19. To measure tear strength, 12 samples of each material were made using a split mold, placed in a water bath until testing, and loaded in tension until failure at a rate of 500 mm/min using a universal testing machine. For cast surface porosity testing, five impressions of a Teflon mold with each material were placed in a water bath (37.8°C) for the in-mouth setting time and poured with vacuum-mixed Silky Rock die stone at 5, 10, 30, and 60 minutes from the start of mixing. The gypsum samples were analyzed with a digital microscope for surface porosity indicative of hydrogen gas release by comparing the surface obtained at each interval with four casts representing no, little, some, and significant porosity. Data analysis was performed using parametric and Kruskal-Wallis analysis of variance (ANOVA), Tukey/Kramer post-hoc tests (α=0.05), and individual Mann-Whitney U tests (α=0.0167). All alginate substitute materials passed the detail reproduction test. Tear strength of the alginate substitute materials was significantly better than alginate and formed three statistically different groups: AlgiNot had the lowest tear strength, Algin-X Ultra had the highest tear strength, and Position Penta Quick had intermediate tear strength. Significant variation in outgassing existed between materials and pouring times (psubstitute materials exhibited the least outgassing and cast porosity 60 minutes after mixing. Detail reproduction and tear strength of alginate substitute materials were superior to traditional alginate. The outgassing effect was minimal for most materials tested. Alginate substitute materials are superior replacements for irreversible hydrocolloid.

  14. RGD-peptide modified alginate by a chemoenzymatic strategy for tissue engineering applications.

    Science.gov (United States)

    Sandvig, Ioanna; Karstensen, Kristin; Rokstad, Anne Mari; Aachmann, Finn Lillelund; Formo, Kjetil; Sandvig, Axel; Skjåk-Bræk, Gudmund; Strand, Berit Løkensgard

    2015-03-01

    One of the main challenges in tissue engineering and regenerative medicine is the ability to maintain optimal cell function and survival post-transplantation. Biomaterials such as alginates are commonly used for immunoisolation, while they may also provide structural support to the cell transplants by mimicking the extracellular matrix. In this study, arginine-glycine-aspartate (RGD)-peptide-coupled alginates of tailored composition were produced by adopting a unique chemoenzymatic strategy for substituting the nongelling mannuronic acid on the alginate. Alginates with and without RGD were produced with high and low content of G. Using carbodiimide chemistry 0.1-0.2% of the sugar units were substituted by peptide. Furthermore, the characterization by (1)H-nuclear magnetic resonance (NMR) revealed by-products from the coupling reaction that partly could be removed by coal filtration. Olfactory ensheathing cells (OECs) and myoblasts were grown in two-dimensional (2D) and 3D cultures of RGD-peptide modified or unmodified alginates obtained by the chemoenzymatically strategy and compared to native alginate. Both OECs and myoblasts adhered to the RGD-peptide modified alginates in 2D cultures, forming bipolar protrusions. OEC encapsulation resulted in cell survival for up to 9 days, thus demonstrating the potential for short-term 3D culture. Myoblasts showed long-term survival in 3D cultures, that is, up to 41 days post encapsulation. The RGD modifications did not result in marked changes in cell viability in 3D cultures. We demonstrate herein a unique technique for tailoring peptide substituted alginates with a precise and flexible composition, conserving the gel forming properties relevant for the use of alginate in tissue engineering. © 2014 Wiley Periodicals, Inc.

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

    Science.gov (United States)

    Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

    2015-01-06

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

  16. Toponymic Restoration in Irkutsk

    Directory of Open Access Journals (Sweden)

    Alexander Snarsky

    2016-10-01

    Full Text Available The article analyzes the discussion on restoration of historical names of public spaces in Irkutsk. It also reviews different approaches to the problem that appeared in the historical science and publicism. The author says about the necessity of a strictly historical approach to the toponymic restoration.

  17. Restoration of southern ecosystems

    Science.gov (United States)

    John A. Stanturf; Emile S. Gardiner; Kenneth Outcalt; William H. Conner; James M. Guldin

    2004-01-01

    Restoration of the myriad communities of bottomland hardwood and wetland forests and of the diverse communities of fire-dominated pine forests is the subject of intense interest in the Southern United States. Restoration practice is relatively advanced for bottomland hardwoods and longleaf pine (Pinus palustris Mill.), and less so for swamps and...

  18. Ecological restoration [book review

    Science.gov (United States)

    Eric J. Gustafson

    2010-01-01

    Ecological restoration has increased in prominence in recent years as environmental policies have slowed the rate of environmental degradation in many parts of the world and practitioners have looked for active ways to reverse the damage. Because of the vast number of types and contexts of degraded ecological systems, the field of ecological restoration is still very...

  19. Are we restoring enough?

    NARCIS (Netherlands)

    Hof, A.R.; Hjältén, J.

    2017-01-01

    Habitat restoration is often implemented to mitigate the negative effects of intensive forestry on biodiversity. It may be increasingly adopted in future to alleviate additional negative effects of climate change. Ascertaining the restoration effort needed to fulfill project goals is difficult.

  20. Influence of hydrophobic modification in alginate-based hydrogels for biomedical applications

    Science.gov (United States)

    Choudhary, Soumitra

    Alginate has been exploited commercially for decades in foods, textiles, paper, pharmaceutical industries, and also as a detoxifier for removing heavy metals. Alginate is also popular in cell encapsulation because of its relatively mild gelation protocol and simple chemistry with which biological active entities can be immobilized. Surface modification of alginate gels has been explored to induce desired cell interactions with the gel matrix. These modifications alter the bulk properties, which strongly determine on how cells feel and response to the three-dimensional microenvironment. However, there is a need to develop strategies to engineer functionalities into bulk alginate hydrogels that not only preserve their inherent qualities but are also less toxic. In this thesis, our main focus was to optimize the mechanical properties of alginate-based hydrogels, and by doing so control the performance of the biomaterials. In the first scheme, we used alginate and hydrophobically modified ethyl hydroxy ethyl cellulose as components in interpenetrating polymer network (IPN) gels. The second network was used to control gelation time and rheological properties. We believe these experiments also may provide insight into the mechanical and structural properties of more complex biopolymer gels and naturally-occurring IPNs. Next, we worked on incorporating a hydrophobic moiety directly into the alginate chain, resulting in materials for extended release of hydrophobic drugs. We successfully synthesized hydrophobically modified alginate (HMA) by attaching octylamine groups onto the alginate backbone by standard carbodiimide based amide coupling reaction. Solubility of several model hydrophobic drugs in dilute HMA solutions was found to be increased by more than an order of magnitude. HMA hydrogels, prepared by crosslinking the alginate chains with calcium ions, were found to exhibit excellent mechanical properties (modulus ˜100 kPa) with release extended upto 5 days. Ability

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

    Directory of Open Access Journals (Sweden)

    Genaro A. Paredes-Juarez

    2014-03-01

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

  2. 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.

  3. Retributive and restorative justice.

    Science.gov (United States)

    Wenzel, Michael; Okimoto, Tyler G; Feather, Norman T; Platow, Michael J

    2008-10-01

    The emergence of restorative justice as an alternative model to Western, court-based criminal justice may have important implications for the psychology of justice. It is proposed that two different notions of justice affect responses to rule-breaking: restorative and retributive justice. Retributive justice essentially refers to the repair of justice through unilateral imposition of punishment, whereas restorative justice means the repair of justice through reaffirming a shared value-consensus in a bilateral process. Among the symbolic implications of transgressions, concerns about status and power are primarily related to retributive justice and concerns about shared values are primarily related to restorative justice. At the core of these processes, however, lies the parties' construal of their identity relation, specifically whether or not respondents perceive to share an identity with the offender. The specific case of intergroup transgressions is discussed, as are implications for future research on restoring a sense of justice after rule-breaking.

  4. 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

  5. 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.

  6. The relationship between the inflammatory response and cell adhesion on alginate-chitosan-alginate microcapsules after transplantation.

    Science.gov (United States)

    Li, Shen; Zhang, Ying; Chen, Li; Li, Na; Xie, Hongguo; Guo, Xin; Zhao, Shan; Yu, Weiting; Lv, Yan; Lv, Guojun; Wu, Huijian; Ma, Xiaojun

    2015-07-01

    Cell microencapsulation technology is a potential alternative therapy, but cell overgrowth and adhesion on the microcapsules after transplantation shortens their time of therapeutic efficacy. Inflammatory cells were the main cells that adhered to the microcapsules, so understanding the body's inflammatory processes would help to better identify the mechanisms of cell adhesion to the outer surface of the microcapsules. Our study measured the inflammatory cells and the cytokines and characterized the associated changes in the alginate-chitosan-alginate (ACA) microcapsules 1, 7, 14, and 28 days after implantation in the peritoneal cavity. Then the relationship between the inflammatory response and cell adhesion on the microcapsules was evaluated by multiple regression analysis. The results showed that the microcapsules did not evoke a systemic inflammatory response, but initiated a local inflammatory response in the peritoneal cavity. Furthermore, the correlation analysis showed that the level of cell adhesion on the microcapsules was related to the number of lymphocytes and macrophages, and the amount of IL-6, IL-10, and MCP-1 in the peritoneal cavity. Our results may provide a foundation for reducing the immune response to these microcapsules, prolonging graft survival and improving the efficacy of these treatments. © 2014 Wiley Periodicals, Inc.

  7. 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.

  8. Nanoparticulate assembly of mannuronic acid- and guluronic acid-rich alginate: oral insulin carrier and glucose binder.

    Science.gov (United States)

    Kadir, Aminah; Mokhtar, Mohammad Tarmizi Mohd; Wong, Tin Wui

    2013-12-01

    The relationship of high and low molecular weight mannuronic acid (M)- and guluronic acid (G)-rich alginate nanoparticles as oral insulin carrier was elucidated. Nanoparticles were prepared through ionotropic gelation using Ca(2+) , and then in vitro physicochemical attributes and in vivo antidiabetic characteristics were examined. The alginate nanoparticles had insulin release retarded when the matrices had high alginate-to-insulin ratio or strong alginate-insulin interaction via OH moiety. High molecular weight M-rich alginate nanoparticles were characterized by assemblies of long polymer chains that enabled insulin encapsulation with weaker polymer-drug interaction than nanoparticles prepared from other alginate grades. They were able to encapsulate and yet release and have insulin absorbed into systemic circulation, thereby lowering rat blood glucose. High molecular weight G- and low molecular weight M-rich alginate nanoparticles showed remarkable polymer-insulin interaction. This retarded the drug release and negated its absorption. Blood glucose lowering was, however, demonstrated in vivo with insulin-free matrices of these nanoparticles because of the strong alginate-glucose binding that led to intestinal glucose retention. Alginate nanoparticles can be used as oral insulin carrier or glucose binder in the treatment of diabetes as a function of its chemical composition. High molecular weight M-rich alginate nanoparticles are a suitable vehicle for future development into oral insulin carrier. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  9. The fast release of stem cells from alginate-fibrin microbeads in injectable scaffolds for bone tissue engineering

    Science.gov (United States)

    Zhou, Hongzhi; Xu, Hockin H. K.

    2011-01-01

    Stem cell-encapsulating hydrogel microbeads of several hundred microns in size suitable for injection, that could quickly degrade to release the cells, are currently unavailable. The objectives of this study were to: (1) develop oxidized alginate-fibrin microbeads encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs); (2) investigate microbead degradation, cell release, and osteogenic differentiation of the released cells for the first time. Three types of microbeads were fabricated to encapsulate hUCMSCs: (1) Alginate microbeads; (2) oxidized alginate microbeads; (3) oxidized alginate-fibrin microbeads. Microbeads with sizes of about 100–500 µm were fabricated with 1×106 hUCMSCs/mL of alginate. For the alginate group, there was little microbead degradation, with very few cells released at 21 d. For oxidized alginate, the microbeads started to slightly degrade at 14 d. In contrast, the oxidized alginate-fibrin microbeads started to degrade at 4 d and released the cells. At 7 d, the number of released cells greatly increased and showed a healthy polygonal morphology. At 21 d, the oxidized alginate-fibrin group had a live cell density that was 4-fold that of the oxidized alginate group, and 15-fold that of the alginate group. The released cells had osteodifferentiation, exhibiting highly elevated bone marker gene expressions of ALP, OC, collagen I, and Runx2. Alizarin staining confirmed the synthesis of bone minerals by hUCMSCs, with the mineral concentration at 21 d being 10-fold that at 7 d. In conclusion, fast-degradable alginate-fibrin microbeads with hUCMSC encapsulation were developed that could start to degrade and release the cells at 4 d. The released hUCMSCs had excellent proliferation, osteodifferentiation, and bone mineral synthesis. The alginate-fibrin microbeads are promising to deliver stem cells inside injectable scaffolds to promote tissue regeneration. PMID:21757229

  10. Fracture resistance of posterior teeth restored with modern restorative materials.

    Science.gov (United States)

    Hamouda, Ibrahim M; Shehata, Salah H

    2011-11-01

    We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance.

  11. Research perspectives for restoration

    Directory of Open Access Journals (Sweden)

    Francesco Gurrieri

    2016-11-01

    Full Text Available The essay proposes a critical overview on the basic principles of restoration comparing with the evolution of aesthetics ideals. Starting both from the Roberto Pane theory and the fundamental documents of the discipline (Restoration Charts and Venice Chart specially the essay points out the contemporary crises caused by Post-Modernism and the coming of new aesthetic condition. Thus the paper deepens the concept of “naught” and “nowhere” coming to prospect new opportunities for restoration in the framework of reuse project referring to the latest experience of the New Museum of Santa Maria del Fiore in Florence, Italy.

  12. Fabrication of micro-alginate gel tubes utilizing micro-gelatin fibers

    Science.gov (United States)

    Sakaguchi, Katsuhisa; Arai, Takafumi; Shimizu, Tatsuya; Umezu, Shinjiro

    2017-05-01

    Tissues engineered utilizing biofabrication techniques have recently been the focus of much attention, because these bioengineered tissues have great potential to improve the quality of life of patients with various hard-to-treat diseases. Most tissues contain micro-tubular structures including blood vessels, lymphatic vessels, and bile canaliculus. Therefore, we bioengineered a micro diameter tube using alginate gel to coat the core gelatin gel. Micro-gelatin fibers were fabricated by the coacervation method and then coated with a very thin alginate gel layer by dipping. A micro diameter alginate tube was produced by dissolving the core gelatin gel. Consequently, these procedures led to the formation of micro-alginate gel tubes of various shapes and sizes. This biofabrication technique should contribute to tissue engineering research fields.

  13. Alginate lyase: Review of major sources and classification, properties, structure-function analysis and applications

    Science.gov (United States)

    Zhu, Benwei; Yin, Heng

    2015-01-01

    Alginate lyases catalyze the degradation of alginate, a complex copolymer of α-L-guluronate and its C5 epimer β-D-mannuronate. The enzymes have been isolated from various kinds of organisms with different substrate specificities, including algae, marine mollusks, marine and terrestrial bacteria, and some viruses and fungi. With the progress of structural biology, many kinds of alginate lyases of different polysaccharide lyases families have been characterized by obtaining crystal structures, and the catalytic mechanism has also been elucidated. Combined with various studies, we summarized the source, classification and properties of the alginate lyases from different polysaccharide lyases families. The relationship between substrate specificity and protein sequence was also investigated. PMID:25831216

  14. Interpenetrating polymer networks of alginate and polyethylene glycol for encapsulation of islets of Langerhans.

    Science.gov (United States)

    Desai, N P; Sojomihardjo, A; Yao, Z; Ron, N; Soon-Shiong, P

    2000-01-01

    A mixture of alginate and polyethylene glycol acrylate was investigated as a system for the encapsulation of islets of Langerhans. This system showed dual crosslinkability: the alginate was ionically crosslinked by multivalent cations, and the PEG was covalently crosslinked by photoactivated free radical polymerization. The major advantage of the dually crosslinkable system was the chemical stability of the resultant gels due to the presence of covalent bonds that maintain the integrity of the gel as opposed to reversible ionic linkages that were the only mode of crosslinkage in previous generations of alginate-based encapsulation systems. The physical aspects of gelation of such alginate/PEG compositions were investigated. Diffusion of dextrans of known molecular weights through these gels was studied in order to shed light on the hydrogel porosity and permeability. In vitro viability and function tests demonstrated that these gels were biocompatible. Islets encapsulated in these systems were healthy and retained both viability and insulin secretory function.

  15. Research progress in coating techniques of alginate gel polymer for cell encapsulation.

    Science.gov (United States)

    Simó, Guillermo; Fernández-Fernández, Encarnación; Vila-Crespo, Josefina; Ruipérez, Violeta; Rodríguez-Nogales, José Manuel

    2017-08-15

    Cell encapsulation is used as a biotechnology tool to solve the technological problems derived from handling and application of cells in a great range of fields. This involves immobilization of the cells within a polymeric gel that permits the preservation of their metabolic activity. Alginate is widely established as the most suitable polymer for cell encapsulation. However, alginate gel capsules suffer several disadvantages because of their lack of mechanical and chemical stability. This review summarizes results of recent advances in coating techniques that include ionic and covalent cross-linking between alginate and coating materials for cell encapsulation as a strategy to solve the disadvantages mentioned before. Throughout this review, physicochemical properties of coated-alginate capsules and the effect of coating process on metabolic activity and viability of immobilized cells have been specially discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Inert Reassessment Document for Propylene glycol alginate - CAS No. 9005-37-2

    Science.gov (United States)

    As an inert pesticide ingredient, propylene glycol alginate is exempt from the requirement for a tolerance when used as a deforming agent in pesticide formulations applies to growing crops, or to raw agricultural commodities after harvest.

  17. Combinatory approach of methacrylated alginate and acid monomers for concrete applications.

    Science.gov (United States)

    Mignon, Arn; Devisscher, Dries; Graulus, Geert-Jan; Stubbe, Birgit; Martins, José; Dubruel, Peter; De Belie, Nele; Van Vlierberghe, Sandra

    2017-01-02

    Polysaccharides, and especially alginate, can be useful for self-healing of cracks in concrete. Instead of weak electrostatic bonds present within calcium alginate, covalent bonds, by methacrylation of the polysaccharides, will result in mechanically stronger superabsorbent polymers (SAPs). These methacrylated alginate chains as backbone are combined with two acrylic monomers in a varying molar fraction. These SAPs show a moisture uptake capacity up to 110% their own weight at a relative humidity of 95%, with a negligible hysteresis. The swelling capacity increased (up to 246 times its own weight) with a decreasing acrylic acid/2 acrylamido-2-methylpropane sulfonic acid ratio. The SAPs also showed a thermal stability up to 200°C. Interestingly, the SAP composed of alginate and acrylic acid exerted a very limited decrease in compressive strength (up to 7% with addition of 1wt% SAP) rendering this material interesting for the envisaged self-healing application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. GLYCOL METHACRYLATE EMBEDDING OF ALGINATE-POLYLYSINE MICROENCAPSULATED PANCREATIC-ISLETS

    NARCIS (Netherlands)

    FRITSCHY, WM; GERRITS, PO; WOLTERS, GHJ; PASMA, A; VANSCHILFGAARDE, R

    A method for processing and embedding alginate-polylysine microencapsulated pancreatic tissue in glycol methacrylate resin (GMA) is described. Fixation in 4% phosphate buffered formaldehyde, processing in ascending concentrations of glycol methacrylate monomer and embedding in Technovit 7100 results

  19. Chitosan-alginate capsules as oral delivery system for insulin: studies in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    C. A. RODRIGUES

    2009-05-01

    Full Text Available The aim of this study was to assess chitosan:alginate capsules as gastric resistant systems for oral administration of insulin. Chitosan:alginate capsules of insulin were tested in simulated gastric and intestinal media and in vivo. The capsules released only about 20% of the insulin after 60 minutes of incubation in simulated gastric medium. On the other hand, almost all the encapsulated insulin was released after being incubated for 90 min in simulated intestinal medium. When capsules containing 20 IU and 40 IU insulin were given to rats by gavage, signifi cantly reduced plasma glucose levels were observed (33.7 % and 51.7%, respectively two hours after the treatment, which returned to normal after six hours. These results indicate that chitosan:alginate capsules are potential carriers for oral protein delivery. Keywords: chitosan:alginate capsules; insulin; oral administration.

  20. Preparation of carbon nanotube-alginate nanocomposite gel for tissue engineering.

    Science.gov (United States)

    Kawaguchi, Minoru; Fukushima, Tadao; Hayakawa, Toru; Nakashima, Naotoshi; Inoue, Yusuke; Takeda, Shoji; Okamura, Kazuhiko; Taniguchi, Kunihisa

    2006-12-01

    A novel scaffold material based on an alginate hydrogel which contained carbon nanotubes (CNTs) was prepared, and its mechanical property and biocompatibility evaluated. Soluble CNTs were prepared with acid treatment and dispersed in sodium alginate solution as a cross-linker. After which, the mechanical property (elastic deformation), saline sorption, histological reaction, and cell viability of the resultant nanocomposite gel (CNT-Alg gel) were evaluated. The CNT-Alg gel showed faster gelling and higher mechanical strength than the conventional alginate gel. Saline sorption amount of freeze-dried CNT-Alg gel was equal to that of the alginate gel. In terms of histological evaluation and cell viability assay, CNT-Alg gel exhibited a mild inflammatory response and non-cytotoxicity. These results thus suggested that CNT-Alg gel could be useful as a scaffold material in tissue engineering with the sidewalls of CNTs acting as active sites for chemical functionalization.

  1. Investigation the influence of dietary fiber on the rheological properties of alginate beads

    Directory of Open Access Journals (Sweden)

    Z. Manev

    2015-03-01

    Full Text Available Abstract. During the current investigation experiments for the preparation of alginate beads with aqueous solutions of sodium alginate, calcium lactate or calcium dichloride and dietary fiber in different concentrations: inulin with varying degrees of polymerization, wheat bran and amidated apple pectin were carried out. The sodium alginate solutions were at constant concentration 3%, while calcium salts in 7% were applied for bead formation. It was proven that the rupture force of alginate beads was always higher than the pure model system regardless of the chemical structure of dietary fibers used. In the result of the carried research the dependence at a certain concentration was established at which the rupture force and deformation of the beads increased gradually.

  2. Synthesis of collagen by bovine chondrocytes cultured in alginate; posttranslational modifications and cell-matrix interaction

    NARCIS (Netherlands)

    Beekman, B.; Verzijl, N.; Bank, R.A.; Von Der Mark, K.; TeKoppele, J.M.

    1997-01-01

    The extracellular matrix synthesized by articular chondrocytes cultured in alginate beads was investigated. Collagen levels increased sigmoidally with time and remained constant after 2 weeks of culture. The presence of cartilage-specific type II collagen was confirmed immunohistochemically.

  3. Densities, cellulases, alginate and pectin lyases of luminous and other heterotrophic bacteria associated with marine algae

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    enzymes. No luminous bacteria examined produced cellulases, but both V. harveyi and V. fischeri strains produced substantial amounts of alginate and pectin lyases. In contrast, cellulase activities were pronounced in non-luminous vibrio, pseudomonad...

  4. 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.

  5. Alginate-pomegranate peels' polyphenols beads: effects of formulation parameters on loading efficiency

    Directory of Open Access Journals (Sweden)

    Wissam Zam

    2014-12-01

    Full Text Available Calcium alginate beads containing pomegranate peels' polyphenol extract were encapsulated by ionic gelation method. The effects of various formulation factors (sodium alginate concentration, calcium chloride concentration, calcium chloride exposure time, gelling bath time maintaining, and extract concentration on the efficiency of extract loading were investigated. The formulation containing an extract of 1 g pomegranate peels in 100 mL distilled water encapsulated with 3 % of sodium alginate cured in 0.05 M calcium chloride for 20 minutes and kept in a gelling bath for 15 minutes was chosen as the best formula regarding the loading efficiency. These optimized conditions allowed the encapsulation of 43.90% of total extracted polyphenols and 46.34 % of total extracted proanthocyanidins. Microencapsulation of pomegranate peels' extract in calcium alginate beads is a promising technique for pharmaceutical and food supplementation with natural antioxidants.

  6. Encapsulation of insulin in chitosan-coated alginate beads: oral therapeutic peptide delivery.

    Science.gov (United States)

    Onal, Seçil; Zihnioğlu, Figen

    2002-05-01

    Insulin was encapsulated in calcium alginate beads coated with chitosan. Its release from alginate-chitosan and alginate-chitosan-glutaraldehyde beads was studied in artificial gastric (pH 1.2) and intestinal (pH 7.5) fluids. By comparing the release amounts, the ionic interaction between alginate-chitosan matrix with the medium pH's, intestinal fluid was found to be the better. The degradation of released insulin was also searched, even after 6 h incubation, the beads remained stable and the undegraded insulin seemed to be sufficient for the physiological conditions. Consequently, it can be said that the system can be offered for oral delivery of the therapeutic peptide drug insulin.

  7. Characterization of an Eukaryotic PL-7 Alginate Lyase in the Marine Red Alga Pyropia yezoensis.

    Science.gov (United States)

    Inoue, Akira; Mashino, Chieco; Uji, Toshiki; Saga, Naotsune; Mikami, Koji; Ojima, Takao

    2015-08-01

    Alginate lyases belonging to polysaccharide lyase family-7 (PL-7) are the most well studied on their structures and functions among whole alginate lyases. However, all characterized PL-7 alginate lyases are from prokaryotic bacteria cells. Here we report the first identification of eukaryotic PL-7 alginate lyase from marine red alga Pyropia yezoensis. The cDNA encoding an alginate lyase PyAly was cloned and was used for the construction of recombinant PyAly (rPyAly) expression system in Escherichia coli. Purified rPyAly was assayed to identify its enzymatic properties. Its expression pattern in P. yessoensis was also investigated. PyAly is likely a secreted protein consisting of an N-terminal signal peptide of 25 residues and a catalytic domain of 216 residues. The amino-acid sequence of the catalytic domain showed 19-29% identities to those of bacterial characterized alginate lyases classified into family PL-7. Recombinant PyAly protein, rPyAly, which was produced with E. coli BL21(DE3) by cold-inducible expression system, drastically decreased the viscosity of alginate solution in the early stage of reaction. The most preferable substrate for rPyAly was the poly(M) of alginate with an optimal temperature and pH at 35(o)C and 8.0, respectively. After reaction, unsaturated tri- and tetra-saccharides were produced from poly(M) as major end products. These enzymatic properties indicated that PyAly is an endolytic alginate lyase belonging to PL-7. Moreover, we found that the PyAly gene is split into 4 exons with 3 introns. PyAly was also specifically expressed in the gametophytic haplopid stage. This study demonstrates that PyAly in marine red alga P. yezoensis is a novel PL-7 alginate lyase with an endolytic manner. PyAly is a gametophyte-specifically expressed protein and its structural gene is composed of four exons and three introns. Thus, PyAly is the first enzymatically characterized eukaryotic PL-7 alginate lyase.

  8. Antimicrobial and anticancer activities of porous chitosan-alginate biosynthesized silver nanoparticles.

    Science.gov (United States)

    Venkatesan, Jayachandran; Lee, Jin-Young; Kang, Dong Seop; Anil, Sukumaran; Kim, Se-Kwon; Shim, Min Suk; Kim, Dong Gyu

    2017-05-01

    The main aim of this study was to obtain porous antimicrobial composites consisting of chitosan, alginate, and biosynthesized silver nanoparticles (AgNPs). Chitosan and alginate were used owing to their pore-forming capacity, while AgNPs were used for their antimicrobial property. The developed porous composites of chitosan-alginate-AgNPs were characterized using Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The FT-IR results revealed the presence of a strong chemical interaction between chitosan and alginate due to polyelectrolyte complex; whereas, the XRD results confirmed the presence of AgNPs in the composites. The dispersion of AgNPs in the porous membrane was uniform with a pore size of 50-500μm. Antimicrobial activity of the composites was checked with Escherichia coli and Staphylococcus aureus. The developed composites resulted in the formation of a zone of inhibition of 11±1mm for the Escherichia coli, and 10±1mm for Staphylococcus aureus. The bacterial filtration efficiency of chitosan-alginate-AgNPs was 1.5-times higher than that of the chitosan-alginate composite. The breast cancer cell line MDA-MB-231 was used to test the anticancer activity of the composites. The IC50 value of chitosan-alginate-AgNPs on MDA-MB-231 was 4.6mg. The developed chitosan-alginate-AgNPs composite showed a huge potential for its applications in antimicrobial filtration and cancer treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Towards a medically approved technology for alginate-based microcapsules allowing long-term immunoisolated transplantation.

    Science.gov (United States)

    Zimmermann, H; Zimmermann, D; Reuss, R; Feilen, P J; Manz, B; Katsen, A; Weber, M; Ihmig, F R; Ehrhart, F; Gessner, P; Behringer, M; Steinbach, A; Wegner, L H; Sukhorukov, V L; Vásquez, J A; Schneider, S; Weber, M M; Volke, F; Wolf, R; Zimmermann, U

    2005-06-01

    The concept of encapsulated-cell therapy is very appealing, but in practice a great deal of technology and know-how is needed for the production of long-term functional transplants. Alginate is one of the most promising biomaterials for immunoisolation of allogeneic and xenogeneic cells and tissues (such as Langerhans islets). Although great advances in alginate-based cell encapsulation have been reported, several improvements need to be made before routine clinical applications can be considered. Among these is the production of purified alginates with consistently high transplantation-grade quality. This depends to a great extent on the purity of the input algal source as well as on the development of alginate extraction and purification processes that can be validated. A key engineering challenge in designing immunoisolating alginate-based microcapsules is that of maintaining unimpeded exchange of nutrients, oxygen and therapeutic factors (released by the encapsulated cells), while simultaneously avoiding swelling and subsequent rupture of the microcapsules. This requires the development of efficient, validated and well-documented technology for cross-linking alginates with divalent cations. Clinical applications also require validated technology for long-term cryopreservation of encapsulated cells to maintaining a product inventory in order to meet end-user demands. As shown here these demands could be met by the development of novel, validated technologies for production of transplantation-grade alginate and microcapsule engineering and storage. The advances in alginate-based therapy are demonstrated by transplantation of encapsulated rat and human islet grafts that functioned properly for about 1 year in diabetic mice.

  10. Microfluidic Generation of Monodisperse, Structurally Homogeneous Alginate Microgels for Cell Encapsulation and 3D Cell Culture.

    Science.gov (United States)

    Utech, Stefanie; Prodanovic, Radivoje; Mao, Angelo S; Ostafe, Raluca; Mooney, David J; Weitz, David A

    2015-08-05

    Monodisperse alginate microgels (10-50 μm) are created via droplet-based microfluidics by a novel crosslinking procedure. Ionic crosslinking of alginate is induced by release of chelated calcium ions. The process separates droplet formation and gelation reaction enabling excellent control over size and homogeneity under mild reaction conditions. Living mesenchymal stem cells are encapsulated and cultured in the generated 3D microenvironments. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Production and in vitro evaluation of macroporous, cell-encapsulating alginate fibres for nerve repair.

    Science.gov (United States)

    Lin, Sharon Chien-Yu; Wang, Yiwei; Wertheim, David F; Coombes, Allan G A

    2017-04-01

    The prospects for successful peripheral nerve repair using fibre guides are considered to be enhanced by the use of a scaffold material, which promotes attachment and proliferation of glial cells and axonal regeneration. Macroporous alginate fibres were produced by extraction of gelatin particle porogens from wet spun fibres produced using a suspension of gelatin particles in 1.5% w/v alginate solution. Gelatin loading of the starting suspension of 40.0, 57.0, and 62.5% w/w resulted in gelatin loading of the dried alginate fibres of 16, 21, and 24% w/w respectively. Between 45 and 60% of the gelatin content of hydrated fibres was released in 1h in distilled water at 37°C, leading to rapid formation of a macroporous structure. Confocal laser scanning microscopy (CLSM) and image processing provided qualitative and quantitative analysis of mean equivalent macropore diameter (48-69μm), pore size distribution, estimates of maximum porosity (14.6%) and pore connectivity. CLSM also revealed that gelatin residues lined the macropore cavities and infiltrated into the body of the alginate scaffolds, thus, providing cell adhesion molecules, which are potentially advantageous for promoting growth of glial cells and axonal extension. Macroporous alginate fibres encapsulating nerve cells [primary rat dorsal root ganglia (DRGs)] were produced by wet spinning alginate solution containing dispersed gelatin particles and DRGs. Marked outgrowth was evident over a distance of 150μm at day 11 in cell culture, indicating that pores and channels created within the alginate hydrogel were providing a favourable environment for neurite development. These findings indicate that macroporous alginate fibres encapsulating nerve cells may provide the basis of a useful strategy for nerve repair. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Design and Fabrication of Anatomical Bioreactor Systems Containing Alginate Scaffolds for Cartilage Tissue Engineering

    OpenAIRE

    Gharravi, Anneh Mohammad; Orazizadeh, Mahmoud; Ansari-Asl, Karim; Banoni, Salem; Izadi, Sina; Hashemitabar, Mahmoud

    2012-01-01

    The aim of the present study was to develop a tissue-engineering approach through alginate gel molding to mimic cartilage tissue in a three-dimensional culture system. The perfusion biomimetic bioreactor was designed to mimic natural joint. The shear stresses exerting on the bioreactor chamber were calculated by Computational Fluid Dynamic (CFD). Several alginate/bovine chondrocyte constructs were prepared, and were cultured in the bioreactor. Histochemical and immunohistochemical staining me...

  13. Alginate-Poly(ethylene glycol) Hybrid Microspheres for Primary Cell Microencapsulation

    OpenAIRE

    Redouan Mahou; Meier, Raphael P H; Bühler, Léo H.; Christine Wandrey

    2014-01-01

    The progress of medical therapies, which rely on the transplantation of microencapsulated living cells, depends on the quality of the encapsulating material. Such material has to be biocompatible, and the microencapsulation process must be simple and not harm the cells. Alginate-poly(ethylene glycol) hybrid microspheres (alg-PEG-M) were produced by combining ionotropic gelation of sodium alginate (Na-alg) using calcium ions with covalent crosslinking of vinyl sulfone-terminated multi-arm poly...

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

    OpenAIRE

    Jovanović Željka; Mišković-Stanković Vesna; Obradović Bojana; Stojkovska Jasmina; Zvicer Jovana

    2012-01-01

    Production of nanocomposite alginate microbeads with electrochemically synthesized silver nanoparticles (AgNPs) based on electrostatic extrusion technique was investigated with respect to potentials for utilization in pharmaceutical and biomedical applications. It was shown that electrochemical synthesis of AgNPs results in reduction of practically all Ag+ ions present in the initial solution yielding stable Ag/alginate colloid solutions that were demonstrated to be suitable for sterili...

  15. Mechanical Properties and Failure Analysis of Visible Light Crosslinked Alginate-Based Tissue Sealants

    OpenAIRE

    Charron, Patrick; Fenn, Spencer L.; Poniz, Alex; Oldinski, Rachael A.

    2016-01-01

    Moderate to weak mechanical properties limit the use of naturally-derived tissue sealants for dynamic medical applications, e.g., sealing a lung leak. To overcome these limitations, we developed visible-light crosslinked alginate-based hydrogels, as either non-adhesive methacrylated alginate (Alg-MA) hydrogel controls, or oxidized Alg-MA (Alg-MA-Ox) tissue adhesive tissue sealants, which form covalent bonds with extracellular matrix (ECM) proteins. Our study investigated the potential for vis...

  16. 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.

  17. Élaboration et caractérisation de fibres mixtes Alginate / Chitosane

    OpenAIRE

    Dumont, Mélanie

    2016-01-01

    In this work, the preparation of chitosan-coated alginate fibers by a wet spin process and the characterization of these fibers, particularly their antibacterial activities are presented. A pilot scale spinning machine was developed during this thesis for the elaboration of calcium alginate fibers. These last, preformed produced were immersed in chitosan acetate solutions. Three coagulation methods of the chitosan coating were explored two of which consist to the immersion of the fibers in a ...

  18. Chitosan-alginate capsules as oral delivery system for insulin: studies in vitro and in vivo

    OpenAIRE

    Rodrigues, C.A.; R. M. LUCINDA-SILVA; P. CLASEN; S. MAFFEZZOLLI; Bürger, C

    2009-01-01

    The aim of this study was to assess chitosan:alginate capsules as gastric resistant systems for oral administration of insulin. Chitosan:alginate capsules of insulin were tested in simulated gastric and intestinal media and in vivo. The capsules released only about 20% of the insulin after 60 minutes of incubation in simulated gastric medium. On the other hand, almost all the encapsulated insulin was released after being incubated for 90 min in simulated intestinal medium. When capsules conta...

  19. Lipoinsulin encapsulated alginate-chitosan capsules: intestinal delivery in diabetic rats.

    Science.gov (United States)

    Ramadas, M; Paul, W; Dileep, K J; Anitha, Y; Sharma, C P

    2000-01-01

    An oral formulation based on liposome encapsulated alginate-chitosan gel capsules was developed for insulin delivery for the treatment of diabetes. Liposome encapsulation helped to increase the encapsulation efficiency of insulin in alginate-chitosan capsules. This formulation delivers insulin in the neutral environment of the intestine, by-passing the acidic media in the stomach, with increased drug absorption and bioavailability. Oral administration of this formulation was found to reduce blood glucose levels when tested in diabetic rats.

  20. Encapsulation of iron nanoparticles in alginate biopolymer for trichloroethylene remediation

    Science.gov (United States)

    Bezbaruah, Achintya N.; Shanbhogue, Sai Sharanya; Simsek, Senay; Khan, Eakalak

    2011-12-01

    Nanoscale zero-valent iron (NZVI) particles (10-90 nm) were encapsulated in biodegradable calcium-alginate capsules for the first time for application in environmental remediation. Encapsulation is expected to offers distinct advances over entrapment. Trichloroethylene (TCE) degradation was 89-91% in 2 h, and the reaction followed pseudo first order kinetics for encapsulated NZVI systems with an observed reaction rate constant ( k obs) of 1.92-3.23 × 10-2 min-1 and a surface normalized reaction rate constant ( k sa) of 1.02-1.72 × 10-3 L m-2 min-1. TCE degradation reaction rates for encapsulated and bare NZVI were similar indicating no adverse affects of encapsulation on degradation kinetics. The shelf-life of encapsulated NZVI was found to be four months with little decrease in TCE removal efficiency.

  1. Progesterone release from magnetic alginate/chitosan microcapsules

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Melina Vasconcelos; Castro, Mayara de Freitas e; Sanchez Rodriguez, Ruben J., E-mail: sanchez@uenf.br [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil); Rojas-Ayala, Chachi; Baggio-Saitovitch, Elisa Maria [Centro Brasileiro de Pesquisa Fisicas (CBPF), Rio de Janeir, RJ (Brazil)

    2015-07-01

    Magnetite nanoparticles (Fe{sub 3}O{sub 4}) were prepared using the hydrothermal method (160°C) in a closed system and characterized with the aid of the techniques of X-ray Diffraction patterns (DRX), Mössbauer spectroscopy and Vibrating Sample Magnetometer (VSM). The Fe{sub 3}O{sub 4} phase showed high crystallinity and medium crystallite size of 19nm with superparamagnetic properties, reversible behavior and saturation magnetization of 43 emu g{sup -1}. The nanoparticles coated with alginate / chitosan were characterized morphologically by Scanning and Transmission Electron Microscope. The microcapsules have a regular spherical shape with the main contribution of the size distribution in the range of 34-53μm. The progesterone released was 14% higher when external magnetic field was applied. (author)

  2. 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.

  3. Alginate/cashew gum nanoparticles for essential oil encapsulation.

    Science.gov (United States)

    de Oliveira, Erick F; Paula, Haroldo C B; de Paula, Regina C M

    2014-01-01

    Alginate/cashew gum nanoparticles were prepared via spray-drying, aiming at the development of a biopolymer blend for encapsulation of an essential oil. Nanoparticles were characterized regarding to their hydrodynamic volume, surface charge, Lippia sidoides essential oil content and release profile, in addition to being analyzed by infrared spectroscopy (FT-IR), thermal analysis (TGA/DSC) and X-ray diffractometry. Nanoparticles in solution were found to have averaged sizes in the range 223-399 nm, and zeta potential values ranging from -30 to -36 mV. Encapsulated oil levels varied from 1.9 to 4.4% with an encapsulation efficiency of up to 55%. The in vitro release profile showed that between 45 and 95% of oil was released within 30-50h. Kinetic studies revealed that release pattern follow a Korsmeyer-Peppas mechanism. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Challenges of ecological restoration

    DEFF Research Database (Denmark)

    Halme, Panu; Allen, Katherine A.; Aunins, Ainars

    2013-01-01

    The alarming rate of ecosystem degradation has raised the need for ecological restoration throughout different biomes and continents. North European forests may appear as one of the least vulnerable ecosystems from a global perspective, since forest cover is not rapidly decreasing and many...... ecosystem services remain at high level. However, extensive areas of northern forests are heavily exploited and have lost a major part of their biodiversity value. There is a strong requirement to restore these areas towards a more natural condition in order to meet the targets of the Convention...... on Biological Diversity. Several northern countries are now taking up this challenge by restoring forest biodiversity with increasing intensity. The ecology and biodiversity of boreal forests are relatively well understood making them a good model for restoration activities in many other forest ecosystems. Here...

  5. Coastal Wetland Restoration Bibliography

    National Research Council Canada - National Science Library

    Yozzo, David

    1997-01-01

    This bibliography was compiled to provide biologists, engineers, and planners at Corps Districts and other agencies/ institutions with a guide to the diverse body of literature on coastal wetland restoration...

  6. Restoration of ailing wetlands.

    Directory of Open Access Journals (Sweden)

    Oswald J Schmitz

    2012-01-01

    Full Text Available It is widely held that humankind's destructive tendencies when exploiting natural resources leads to irreparable harm to the environment. Yet, this thinking runs counter to evidence that many ecological systems damaged by severe natural environmental disturbances (e.g., hurricanes can restore themselves via processes of natural recovery. The emerging field of restoration ecology is capitalizing on the natural restorative tendencies of ecological systems to build a science of repairing the harm inflicted by humans on natural environment. Evidence for this, for example, comes from a new meta-analysis of 124 studies that synthesizes recovery of impacted wetlands worldwide. While it may take up to two human generations to see full recovery, there is promise, given human will, to restore many damaged wetlands worldwide.

  7. Development of PVA-alginate as a matrix for enzymatic decolorization of textile dye in bioreactor system

    Science.gov (United States)

    Yanto, Dede Heri Yuli; Zahara, Syifa; Laksana, Raden Permana Budi; Anita, Sita Heris; Oktaviani, Maulida; Sari, Fahriya Puspita

    2017-01-01

    An immobilization technique using polyvinyl alcohol (PVA) crosslinked with sodium alginate as a matrix has been developed for textile dyes decolorization. Textiles use dye as an addition to the aesthetic value of the product. Dyes are generally used is a textile dye where the waste will be released directly into the waters around 2-20%. Therefore, it is important to develop an enzyme immobilization method using PVA-Alginate as a matrix. Based on the results of the study showed that the PVA-Alginate beads produced high decolorization percent compared to beads which contains only Ca-alginate alone and formula matrix is optimum at PVA 6% and alginate 1.5%. Encapsulation with boric acid at 7% showed optimum decolorization and reduction for enzyme leakage during decolorization. This study suggested that immobilization of enzymes into PVA-alginate matrix might be used as a biodecolorating agent.

  8. 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.

  9. Development of a nutraceutical nano-delivery system through emulsification/internal gelation of alginate.

    Science.gov (United States)

    Mokhtari, Samira; Jafari, Seid Mahdi; Assadpour, Elham

    2017-08-15

    Alginate nano/microspheres are produced by emulsification/internal gelation of sodium alginate dispersed within vegetable oils containing surfactant, followed by CaCl2 addition resulting in hardened particles. In this work, the impact was evaluated of alginate, CaCl2, oil and surfactant content on the size and encapsulation efficiency of nanocarriers containing peppermint phenolic extract and prepared by a low energy internal gelation technique. The results revealed that size of nanoparticles decreased at higher oil and surfactant contents, higher molarity of CaCl2 and lower alginate concentrations. Also, it was found that the encapsulation efficiency was inversely proportional to the size of nanoparticles, and the impact of alginate concentration and surfactant content was markedly higher than the other two factors. The composition of 0.5% alginate, 400ml oil, 0.05M CaCl2 and 100ml surfactant was recognized as the optimized treatment with a reasonable encapsulation efficiency of 5.6% and a nanoparticle size of 785nm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Alginate encapsulation technology supports embryonic stem cells differentiation into insulin-producing cells.

    Science.gov (United States)

    Wang, Nan; Adams, Gary; Buttery, Lee; Falcone, Franco H; Stolnik, Snow

    2009-12-01

    This work investigates an application of the alginate encapsulation technology to the differentiation of embryonic stem (ES) cells into insulin-producing cells. It shows that the ES cells can efficiently be encapsulated within the alginate beads, retaining a high level of cell viability. The alginate encapsulation achieves approximately 10-fold increase in the cell density in the culture, in comparison to the two-dimensional conditions, opening a potential benefit of the technology in large-scale cell culture applications. Manipulations of encapsulation conditions, particularly of the initial alginate concentration, allow the control over both the diffusion of molecules into the alginate matrix (e.g. differentiation factors) as well as control over the matrix porosity/flexibility to permit the proliferation and growth of encapsulated ES aggregates within the bead. Post-differentiation analysis confirms the presence of insulin-positive cells, as judged from immunostaining, insulin ELISA and RT-PCR analysis. The functionality of the encapsulated and differentiated cells was confirmed by their insulin production capability, whereby on glucose challenge the insulin production by the cells differentiated within alginate beads was found to be statistically significantly higher than for the cells from conventional two-dimensional differentiation system.

  11. Adhesive properties of laminated alginate gels for tissue engineering of layered structures.

    Science.gov (United States)

    Gleghorn, Jason P; Lee, Christopher S D; Cabodi, Mario; Stroock, Abraham D; Bonassar, Lawrence J

    2008-06-01

    A significant challenge in tissue engineering is the creation of tissues with stratified morphology or embedded microstructures. This study investigated methods to fabricate composite gels from separately deposited alginate layers and examined the effects of processing methods on the mechanics of adhesion. Laminated alginate gels were created through a three step process which included: treatment of the interfaces with citrate; annealing of the gels to allow for molecular rearrangement of the alginate chains; and exposure to a CaCl(2) to crosslink the alginate sheets. Process variables included volume and concentration of applied citrate, annealing time, incubation time in CaCl(2), and CaCl(2) concentration. Laminated sheets were tested in lap-shear geometry to characterize failure phenomena and mechanical properties. The site of failure within the gel depended on the integrity of the interface, with weaker gels delaminating and gels with mechanical properties similar to that of bulk gels failing randomly throughout the thickness. Citrate volume, citrate concentration, CaCl(2) incubation time, and CaCl(2) concentration altered the mechanical properties of the laminated alginate sheets, while annealing time had little effect on all measured parameters. This study demonstrates the integration of separately fabricated alginate layers to create mechanically or chemically anisotropic or heterogeneous structures. Copyright 2007 Wiley Periodicals, Inc.

  12. Synergistic effect of divalent cations in improving technological properties of cross-linked alginate beads.

    Science.gov (United States)

    Cerciello, Andrea; Del Gaudio, Pasquale; Granata, Veronica; Sala, Marina; Aquino, Rita P; Russo, Paola

    2017-08-01

    Gelling solution parameters are some of the most important variables in ionotropic gelation and consequently influence the technological characteristics of the product. To date, only a few studies have focused on the simultaneous use of multiple cations as gelling agents. With the aim to deeply explore this possibility, in this research we investigated the effect of two divalent cations (Ca 2+ and Zn 2+ ) on alginate beads formation and properties. Alginate beads containing prednisolone (P) as model drug were prepared by prilling technique. The main critical variables of the ionotropic gelation process i.e. composition of the aqueous feed solutions (sodium alginate and prednisolone concentration) and cross-linking conditions (Ca 2+ , Zn 2+ or Ca 2+ +Zn 2+ ), were studied. The obtained beads were characterized and their in vitro release performances were assessed in conditions simulating the gastrointestinal environment. Results evidenced a synergistic effect of the two cations, affecting positively both the encapsulation efficiency and the ability of the alginate polymeric matrix to control the drug release. A Ca 2+ /Zn 2+ ratio of 4:1, in fact, exploited the Ca 2+ ability of establish quicker electrostatic interactions with guluronic groups of alginate and the Zn 2+ ability to establish covalent-like bonds with carboxylate groups of both guluronic and mannuronic moieties of alginate. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Alginic acid decreases postprandial upright gastroesophageal reflux. Comparison with equal-strength antacid.

    Science.gov (United States)

    Castell, D O; Dalton, C B; Becker, D; Sinclair, J; Castell, J A

    1992-04-01

    This study tested the hypothesis that (alginic) acid may have a preferential effect on reflux in the upright position. We evaluated the effect of a compound containing alginic acid plus antacid (extra-strength Gaviscon) versus active control antacid with equal acid-neutralizing capacity on intraesophageal acid exposure following a high-fat meal (61% fat: sausage, egg, and biscuit). In random sequence, each of the 10 volunteers received either alginic acid-antacid or control antacid immediately following and 1, 2, and 3 hr after the meal. The sequence was repeated for both test drugs in the supine and upright positions with constant pH monitoring. Alginic acid-antacid significantly decreased postprandial reflux in the upright position compared to an equal amount of antacid. This effect did not occur in the supine position. These findings support the hypothesis that alginic acid is primarily effective in the upright position and the clinical observations of the effectiveness of alginic acid on daytime reflux symptoms.

  14. Nanogel and superparamagnetic nanocomposite based on sodium alginate for sorption of heavy metal ions.

    Science.gov (United States)

    Lakouraj, Moslem Mansour; Mojerlou, Fatemeh; Zare, Ehsan Nazarzadeh

    2014-06-15

    Novel sodium alginate supported tetrasodium thiacalix[4]arene tetrasulfonate (TSTC[4]AS-s-SA) nanogel was prepared using sodium alginate nanoparticles. Then, superparamagnetic nanocomposite of sodium alginate (Fe3O4@TSTC[4]AS-s-SA) was fabricated from coprecipitation of sodium alginate supported tetrasodium thiacalix[4]arene tetrasulfonate and in situ generated Fe3O4 nanoparticles. Structural, morphological, surface, thermal and magnetic properties of the nanoadsorbents were studied by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM), respectively. Adsorptions of Cu(II), Cd(II), Pb(II), Co(II), Ni(II) and Cr(III) ions onto nanoadsorbents were studied in aqueous condition at pH=7. The results indicated that incorporation of thiacalix[4]arene tetrasulfonate and Fe3O4 into sodium alginate nanoparticles increased the adsorption capacity of sodium alginate bioadsorbents, and led to the magnetic property. The TSTC[4]AS-s-SA nanogels consist of rod-like structure with an average diameter of 50 nm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Alginate hydrogels modified with low molecular weight hyaluronate for cartilage regeneration.

    Science.gov (United States)

    Park, Honghyun; Lee, Hyun Ji; An, Hyoseok; Lee, Kuen Yong

    2017-04-15

    Alginate is a typical biomaterial that forms hydrogels in the presence of calcium ions and has often been utilized in tissue engineering approaches. However, it lacks biofunctionality in the form of interactions with cells and proteins. Hyaluronate, a main component of glycosaminoglycans, provides CD44-specific interactions with chondrocytes but typically requires chemical cross-linking agents to fabricate hydrogels, which may cause unexpected side effects in the body. In this study, we propose the design and fabrication of a hybrid structure of alginate and hyaluronate useful for cartilage regeneration. Alginate was used as a backbone, and hyaluronate with a low molecular weight was introduced to the backbone to fabricate alginate-hyaluronate hybrid coupled by ethylenediamine. We hypothesized that alginate-hyaluronate hybrid (AH) could maintain its ability to form gels in the presence of calcium ions and could be useful for cartilage regeneration as an injectable system. Characteristics of AH hydrogels containing various composition ratios of hyaluronate to alginate were investigated, and the chondrogenic potential of ATDC5 cells encapsulated within AH hydrogels was evaluated in vitro. Consequently, AH hydrogels having a defined polymer composition and mechanical stiffness were useful to successfully regulate chondrogenic differentiation and to maintain the chondrocytic cell phenotype, which may lead to many useful applications in cartilage regeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Laser-assisted printing of alginate long tubes and annular constructs.

    Science.gov (United States)

    Yan, Jingyuan; Huang, Yong; Chrisey, Douglas B

    2013-03-01

    Laser-assisted printing such as laser-induced forward transfer has been well studied to pattern or fabricate two-dimensional constructs. In particular, laser printing has found increasing biomedical applications as an orifice-free cell and organ printing approach, especially for highly viscous biomaterials and biological materials. Unfortunately, there have been very few studies on the efficacy of three-dimensional printing performance of laser printing. This study has investigated the feasibility of laser tube printing and the effects of sodium alginate concentration and operating conditions such as the laser fluence and laser spot size on the printing quality during laser-assisted printing of alginate annular constructs (short tubes) with a nominal diameter of 3 mm. It is found that highly viscous materials such as alginate can be printed into well-defined long tubes and annular constructs. The tube wall thickness and tube outer diameter decrease with the sodium alginate concentration, while they first increase, then decrease and finally increase again with the laser fluence. The sodium alginate concentration dominates if the laser fluence is low, and the laser fluence dominates if the sodium alginate concentration is low.

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

    Science.gov (United States)

    Herran, C. Leigh; Huang, Yong; Chai, Wenxuan

    2012-08-01

    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.

  19. A new alginate-based rapid method for determining coliforms in milk.

    Science.gov (United States)

    Chang, Su-sen; Gray, Peter M; Woo, Gun-Jo; Kang, Dong-Hyun

    2003-11-01

    A new rapid method for monitoring coliforms was developed on the basis of the instant gelling effects of alginate and calcium. The effectiveness of this new method in the detection of coliforms was evaluated. Tests involving Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, total coliforms in milk, cold-injured coliforms, and total coliforms in raw milk were carried out. The bacterial samples were diluted in 0.2% peptone water containing 90 mM CaCl2 and added into test tubes containing modified purple broth base medium. Coliform concentrations were determined on the basis of the time of color change and gas production in the alginate tubes. All results obtained by the alginate method correlated strongly with those obtained by the conventional violet red bile agar (VRBA) plating method. The alginate method reduced detection time by 12 to 14 h compared with the conventional VRBA plating method. The alginate method can be applied in field studies more easily than melted-agar systems can. The results of this study indicate that the alginate method is an accurate, rapid, simple, and economical way to monitor and estimate concentrations of total coliforms in food.

  20. Stemness of spermatogonial stem cells encapsulated in alginate hydrogel during cryopreservation.

    Science.gov (United States)

    Pirnia, A; Parivar, K; Hemadi, M; Yaghmaei, P; Gholami, M

    2017-06-01

    This study investigated the effect of spermatogonial stem cell encapsulated in alginate hydrogel during cryopreservation, as cells were protected against damage during cryopreservation within the hydrogel. Spermatogonial stem cells were isolated from the testes of Balb/c mice pups (6 days old), purified in laminin-coated dishes and CD90.1 microbeads, encapsulated in alginate hydrogel and then cryopreserved. After thawing, cell viability and Spermatogonial stem cell (SSC) colony diameter were evaluated. After RNA was isolated and cDNA was synthesised, the expression of stemness genes was considered using RT real-time PCR. Finally, spermatogonial stem cells labelled with BrdU were transplanted to busulfan azoospermic mouse models. Lin28a and Sall4 genes were significantly upregulated after cryopreservation in alginate hydrogel. However, cell viability was significantly decreased. The diameter of colonies consisting of spermatogonial stem cells freeze-thawed in alginate microbeads showed no significant difference with fresh spermatogonial stem cells and the control group. The injection of freeze-thawed spermatogonial stem cells encapsulated in alginate hydrogel resulted in spermatogenesis recovery. Alginate mimics the extracellular matrices (ECM) for spermatogonial stem cells; therefore, it can support stemness potential during the cell cryopreservation process and restart spermatogenesis after transplantation. © 2016 Blackwell Verlag GmbH.

  1. Behavior of encapsulated MG-63 cells in RGD and gelatine-modified alginate hydrogels.

    Science.gov (United States)

    Grigore, Alexandra; Sarker, Bapi; Fabry, Ben; Boccaccini, Aldo R; Detsch, Rainer

    2014-08-01

    Achieving cell spreading and proliferation inside hydrogels that are compatible with microencapsulation technology represents a major challenge for tissue engineering scaffolding and for the development of three-dimensional cell culture models. In this study, microcapsules of 650-900 μm in diameter were fabricated from oxidized alginate covalently cross-linked with gelatine (AlGel). Schiff's base bond formed in AlGel, detected by Fourier transform infrared spectroscopy, which confirmed the cross-linking of oxidized alginate with gelatine. Biological properties of alginate based hydrogels were studied by comparing the viability and morphology of MG-63 osteosarcoma cells encapsulated in gelatine and RGD-modified alginate. We hypothesized that the presence of gelatine and RGD will support cell adhesion and spreading inside the microcapsules and finally, also vascular endothelial growth factor (VEGF) secretion. After 4 days of incubation, cells formed extensive cortical protrusions and after 2 weeks they proliferated, migrated, and formed cellular networks through the AlGel material. In contrast, cells encapsulated in pure alginate and in RGD-modified alginate formed spherical aggregates with limited cell mobility and VEGF secretion. Metabolic activity was doubled after 5 days of incubation, making AlGel a promising material for cell encapsulation.

  2. Transport of biological molecules in surfactant-alginate composite hydrogels.

    Science.gov (United States)

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

    2011-11-01

    Obstructed transport of biological molecules can result in improper release of pharmaceuticals or biologics from biomedical devices. Recent studies have shown that nonionic surfactants, such as Pluronic® F68 (F68), positively alter biomaterial properties such as mesh size and microcapsule diameter. To further understand the effect of F68 (incorporated at concentrations well above the critical micelle concentration (CMC)) in traditional biomaterials, the transport properties of BSA and riboflavin were investigated in F68-alginate composite hydrogels, formed by both internal and external cross-linking with divalent cations. Results indicate that small molecule transport (represented by riboflavin) was not significantly hindered by F68 in homogeneously (internally) cross-linked hydrogels (up to an 11% decrease in loading capacity and 14% increase in effective diffusion coefficient, D(eff)), while protein transport in homogeneously cross-linked hydrogels (represented by BSA) was significantly affected (up to a 43% decrease in loading capacity and 40% increase in D(eff)). For inhomogeneously cross-linked hydrogels (externally cross-linked by CaCl(2) or BaCl(2)), the D(eff) increased up to 50 and 83% for small molecules and proteins, respectively. Variation in the alginate gelation method was shown to affect transport through measurable changes in swelling ratio (30% decrease) and observable changes in cross-linking structure as well as up to a 3.6- and 11.8-fold difference in D(eff) for riboflavin and BSA, respectively. Aside from the expected significant changes due to the cross-linking method utilized, protein transport properties were altered due to mesh size restrictions (10-25 nm estimated by mechanical properties) and BSA-F68 interaction (DLS). Taken as a whole, these results show that incorporation of a nonionic surfactant at concentrations above the CMC can affect device functionality by impeding the transport of large biological molecules. Copyright © 2011

  3. CRYOPRESERVATION EFFECTS ON RECOMBINANT MYOBLASTS ENCAPSULATED IN ADHESIVE ALGINATE HYDROGELS

    Science.gov (United States)

    Ahmad, Hajira F.; Sambanis, Athanassios

    2013-01-01

    Cell encapsulation in hydrogels is widely used in tissue engineering applications, including encapsulation of islets or other insulin-secreting cells in pancreatic substitutes. Use of adhesive, bio-functionalized hydrogels is receiving increasing attention, as cell-matrix interactions in 3-D can be important for various cell processes. With pancreatic substitutes, studies have indicated benefits of 3-D adhesion on the viability and/or function of insulin-secreting cells. As long-term storage of microencapsulated cells is critical for their clinical translation, cryopreservation of cells in hydrogels is actively being investigated. Previous studies have examined the cryopreservation response of cells encapsulated in non-adhesive hydrogels using conventional freezing and/or vitrification (ice-free cryopreservation), however, none have systematically compared the two cryopreservation methods with cells encapsulated within an adhesive 3-D environment. The latter would be significant, as evidence suggests adhesion influences cellular response to cryopreservation. Thus, the objective of this study was to determine the response to conventional freezing and vitrification of insulin-secreting cells encapsulated in an adhesive biomimetic hydrogel. Recombinant insulin-secreting C2C12 myoblasts were encapsulated in oxidized RGD-alginate and cultured 1 or 4 days post-encapsulation, cryopreserved, and assessed up to 3 days post-warming for metabolic activity and insulin secretion, and one day post-warming for cell morphology. Besides certain transient differences of the vitrified group relative to the Fresh control, both conventional freezing and vitrification maintained metabolism, secretion and morphology of the recombinant C2C12 cells. Thus, due to a simpler procedure and slightly superior results, conventional freezing is recommended over vitrification for the cryopreservation of C2C12 cells in oxidized RGD-modified alginate. PMID:23499987

  4. Restoring primary anterior teeth.

    Science.gov (United States)

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen.

  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. One-step purification and characterization of alginate lyase from a clinical Pseudomonas aeruginosa with destructive activity on bacterial biofilm

    Directory of Open Access Journals (Sweden)

    Parinaz Ghadam

    2017-05-01

    Full Text Available Objective(s: Pseudomonas aeruginosais a Gram-negative and aerobic rod bacterium that displays mucoid and non-mucoid phenotype. Mucoid strains secrete alginate, which is the main agent of biofilms in chronic P. aeruginosa infections, show high resistance to antibiotics; consequently, the biological disruption of mucoid P. aeruginosa biofilms is an attractive area of study for researchers. Alginate lyase gene (algl is a member of alginate producing operon which by glycosidase activity produces primer for other enzymes in this cluster. Also this activity can destroy the extracellular alginate; therefore this enzyme participates in alginate production and destruction pathway. Alginate lyase causes detachment of a biofilm by reducing its adhesion to the surfaces, and increases phagocytosis and antibiotic susceptibility. In this study, alginate lyase was purified in just one step and its properties were investigated. Materials and Methods: The purification was done by affinity chromatography, analysed by SDS-PAGE, and its effect on P. aeruginosa biofilms was surveyed by micro titer plate assay and SEM. The substrate specificity of the enzyme was determined by PCR. Results: Alginate lyase from isolate 48 was purified in one step. It is more thermally resistant than alginate lyase from Pseudomonas aeruginosa PAO1 and poly M, poly G and poly MG alginate were the substrate of this enzyme. Moreover, it has an eradication effect on biofilms from P. aeruginosa 48 and PAO1. Conclusion: In this study an alginate lyase with many characteristics suitable in medicine such as thermal stability, effective on poly M alginate, and bacterial biofilm destructive was introduced and purified.

  7. Pseudomonas aeruginosa biofilms exposed to imipenem exhibit changes in global gene expression and beta-lactamase and alginate production

    DEFF Research Database (Denmark)

    Bagge, Niels; Schuster, Martin; Hentzer, Morten

    2004-01-01

    . As expected, the most strongly induced gene was ampC, which codes for chromosomal beta-lactamase. We also found that genes coding for alginate biosynthesis were induced by exposure to imipenem. Alginate production is correlated to the development of impaired lung function, and P. aeruginosa strains isolated...... from chronically colonized lungs of CF patients are nearly always mucoid due to the overproduction of alginate. Exposure to subinhibitory concentrations of imipenem caused structural changes in the biofilm, e.g., an increased biofilm volume. Increased levels of alginate production may be an unintended...

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

    Science.gov (United States)

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

    2011-06-01

    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 fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.

  9. Alginate hydrogel protects encapsulated hepatic HuH-7 cells against hepatitis C virus and other viral infections.

    Directory of Open Access Journals (Sweden)

    Nhu-Mai Tran

    Full Text Available Cell microencapsulation in alginate hydrogel has shown interesting applications in regenerative medicine and the biomedical field through implantation of encapsulated tissue or for bioartificial organ development. Although alginate solution is known to have low antiviral activity, the same property regarding alginate gel has not yet been studied. The aim of this work is to investigate the potential protective effect of alginate encapsulation against hepatitis C virus (HCV infection for a hepatic cell line (HuH-7 normally permissive to the virus. Our results showed that alginate hydrogel protects HuH-7 cells against HCV when the supernatant was loaded with HCV. In addition, alginate hydrogel blocked HCV particle release out of the beads when the HuH-7 cells were previously infected and encapsulated. There was evidence of interaction between the molecules of alginate hydrogel and HCV, which was dose- and incubation time-dependent. The protective efficiency of alginate hydrogel towards HCV infection was confirmed against a variety of viruses, whether or not they were enveloped. This promising interaction between an alginate matrix and viruses, whose chemical mechanisms are discussed, is of great interest for further medical therapeutic applications based on tissue engineering.

  10. Synthesis and Characterization of Sodium Alginate Conjugate and Study of Effect of Conjugation on Drug Release from Matrix Tablet.

    Science.gov (United States)

    Satheeshababu, B K; Mohamed, I

    2015-01-01

    The aim of the present research work to study the effect of conjugation of the polymer on drug release from the matrix tablets. Sodium alginate L-cysteine conjugate was achieved by covalent attachment of thiol group of L-cysteine with the primary amino group of sodium alginate through the amide bonds formed by primary amino groups of the sodium alginate and the carboxylic acid group of L-cysteine. The synthesised sodium alginate L-cysteine conjugate was characterised by determining of charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. To study the effect of conjugation on drug release pattern, the matrix tablets were prepared using various proportions of sodium alginate and sodium alginate L-cysteine conjugate along with atorvastatin calcium as model drug. The wet granulation technique was adopted and prepared matrix tablets were evaluated for various physical parameters. The in vitro drug release study results suggested that tablet formulated in combination of sodium alginate and sodium alginate L-cysteine conjugate S4 showed 100% after 8 h drug release whereas formulated with only sodium alginate S0 released 40% in 8 h.

  11. Feasibility of Marine Microalgae Immobilization in Alginate Bead for Marine Water Treatment: Bead Stability, Cell Growth, and Ammonia Removal

    Directory of Open Access Journals (Sweden)

    Chen-Lin Soo

    2017-01-01

    Full Text Available Sodium alginate is the most commonly used polymer matrix in microalgae immobilization for water treatment. However, the susceptibility of alginate matrixes to cation chelating agents and antigelling cation limits the use of alginates in estuarine and marine systems. Hence, the present study aims to investigate the stability of alginate bead in marine water and the feasibility of microalgae to grow when immobilized in alginate bead for marine water treatment. Different concentrations of alginate and hardening cation calcium were used to formulate beads. The beads were incubated in Guillard’s f/2 medium and shaken vigorously by using orbital shaker for 15 days. The results indicated that bead stability was enhanced by increasing alginate and CaCl2 concentrations. Subsequently, the marine microalga, Nannochloropsis sp., was immobilized in calcium alginate bead. The growth and ammoniacal-nitrogen (NH4+-N uptake by immobilized cell were compared with free cell culture in f/2 medium. Specific growth rate of immobilized cell (0.063 hr−1 was significantly higher than free cell (0.027 hr−1. There was no significant difference on specific uptake rate of free cell and immobilized cell; but immobilized cell removed significantly more NH4+-N (82.2% than free cell (47.3% culture at the end of the experiment. The present study demonstrated the potential use of alginate immobilization technique in marine microalgae culture and water treatment simultaneously.

  12. Ecosystem Restoration: A Manager's Perspective

    Science.gov (United States)

    James G. Kenna; Gilpin R., Jr. Robinson; Bill Pell; Michael A. Thompson; Joe McNeel

    1999-01-01

    Elements of ecological restoration underlie much of what we think of as ecosystem management, and restoration projects on federal lands represent some of the most exciting, challenging, and convincing demonstrations of applied ecosystem management. The Society for Ecological Restoration defined restoration as "the process of reestablishing to the extent possible...

  13. A study of the chain stiffness and extension of alginates, in vitro epimerized alginates, and periodate-oxidized alginates using size-exclusion chromatography combined with light scattering and viscosity detectors.

    Science.gov (United States)

    Vold, Inger Mari Nygård; Kristiansen, Kåre A; Christensen, Bjørn E

    2006-07-01

    A series of alginates isolated from the stem and leaf of a brown algae (Laminaria hyperborea), bacterial mannuronan, in vitro epimerized mannuronans, and periodate oxidized alginates were analyzed by size-exclusion chromatography (SEC) combined with online multiangle laser light scattering (MALS) and viscometry (collectively abbreviated SMV). Selected samples were also analyzed off-line using low-angle laser light scattering and capillary viscometry. Excellent agreement between the two methods was obtained for properly purified samples. In contrast, abnormal results were obtained for some industrial samples due to the presence of particulate material. Naturally occurring alginates and in vitro epimerized mannuronans were found to obey essentially the same RG-M and [eta]-M relations, and hence, the same Mark-Houwink-Sakurada (MHS) equations (valid for I = 0.10 M): 20 000 g/mol < M < 100 000 g/mol, [eta] = 0.0054 .M(1.00); 100 000 g/mol < M < 1 000 000 g/mol, [eta] = 0.071 .M(0.89). Application of the wormlike chain model to the [eta]-M data obtained by SMV yielded persistence lengths (q) of 15 nm for all alginates at an ionic strength of 0.17 M. Intrinsic viscosities corresponding to infinite ionic strength were estimated on the basis of Smidsrød's B-parameter, and the wormlike chain model then yielded q = 12 nm. Periodate oxidized alginates showed, in contrast, a pronounced decrease in persistence length with increasing degree of oxidation, reaching values below 4 nm at 44% oxidation. Periodate oxidation also resulted in some depolymerization, even in the presence of a free-radical scavenger.

  14. Iron-Regulated Expression of Alginate Production, Mucoid Phenotype, and Biofilm Formation by Pseudomonas aeruginosa

    Science.gov (United States)

    Wiens, Jacinta R.; Vasil, Adriana I.; Schurr, Michael J.; Vasil, Michael L.

    2014-01-01

    ABSTRACT Pseudomonas aeruginosa strains of non-cystic fibrosis (non-CF) origin do not produce significant amounts of extracellular alginate and are nonmucoid. In CF, such isolates can become mucoid through mutation of one of the genes (mucA, mucB, mucC, or mucD) that produce regulatory factors that sequester AlgU, required for increased expression of alginate genes. Mutation of the muc genes in the nonmucoid PAO1, PA14, PAKS-1, and Ps388 strains led to increased levels of extracellular alginate and an obvious mucoid phenotype, but only under iron-limiting growth conditions (≤5 µM), not under iron-replete conditions (≥10 µM). In contrast, >50% of P. aeruginosa isolates from chronic CF pulmonary infections expressed increased levels of alginate and mucoidy both under iron-limiting and iron-replete conditions (i.e., iron-constitutive phenotype). No single iron regulatory factor (e.g., Fur, PvdS) was associated with this loss of iron-regulated alginate expression and mucoidy in these CF isolates. However, the loss of only pyoverdine production, or its uptake, abrogated the ability of P. aeruginosa to produce a robust biofilm that represents the Psl-type of biofilm. In contrast, we show that mutation of the pyoverdine and pyochelin biosynthesis genes and the pyoverdine receptor (FpvA) lead to iron-constitutive expression of the key alginate biosynthesis gene, algD, and an explicitly mucoid phenotype in both iron-limiting and iron-replete conditions. These data indicate that alginate production and mucoidy, in contrast to other types of biofilms produced by P. aeruginosa, are substantially enhanced under iron limitation. These results also have compelling implications in relation to the use of iron chelators in the treatment of P. aeruginosa CF infections. PMID:24496793

  15. Enrichment of committed human nucleus pulposus cells expressing chondroitin sulfate proteoglycans under alginate encapsulation.

    Science.gov (United States)

    Sun, Y; Lv, M; Zhou, L; Tam, V; Lv, F; Chan, D; Wang, H; Zheng, Z; Cheung, K M C; Leung, V Y L

    2015-07-01

    Intervertebral disc (IVD) degeneration is associated with a malfunction of the nucleus pulposus (NP). Alginate culturing provides a favorable microenvironment for the phenotypic maintenance of chondrocyte-like NP cells. However, NP cells are recently evidenced to present heterogeneous populations, including progenitors, fibroblastic cells and primitive NP cells. The aim of this study is to profile the phenotypic changes of distinct human NP cells populations and describe the dynamic expression of chondroitin sulfate glycosaminoglycans (CS-GAGs) in extended alginate encapsulation. Non-degenerated (ND-NPC) and degenerated (D-NPC) NP cells were expanded in monolayers, and subject to 28-day culture in alginate after serial passaging. CS-GAG compositional expression in monolayer-/alginate-cultured NP cells was evaluated by carbohydrate electrophoresis. Cellular phenotypic changes were assessed by immunologic detection and gene expression analysis. Relative to D-NPC, ND-NPC displayed remarkably higher expression levels of chondroitin-4-sulfate GAGs over the 28-day culture. Compared with monolayer culture, ND-NPC showed increased NP marker expression of KRT18, KRT19, and CDH2, as well as chondrocyte markers SOX9 and MIA in alginate culture. In contrast, expression of fibroblastic marker COL1A1, COL3A1, and FN1 were reduced. Interestingly, ND-NPC showed a loss of Tie2+ but gain in KRT19+/CD24+ population during alginate culture. In contrast, D-NPC showed more consistent expression levels of NP surface markers during culture. We demonstrate for the first time that extended alginate culture selectively enriches the committed NP cells and favors chondroitin-4-sulfate proteoglycan production. These findings suggest its validity as a model to investigate IVD cell function. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  16. The effect of oxidation on the degradation of photocrosslinkable alginate hydrogels

    Science.gov (United States)

    Jeon, Oju; Alt, Daniel S.; Ahmed, Shaoly M.; Alsberg, Eben

    2013-01-01

    Recently, we reported on a new photocrosslinkable alginate-based hydrogel, which has controllable physical and cell adhesive properties. The macromer solution containing cells can be injected in a minimally invasive manner into a defect site and crosslinked while maintaining high cell viability. The number of hydrolyzable ester bonds in the formed crosslinks may be controlled by altering the degree of methacrylation on the alginate polymer backbone. However, the degradation rate of the hydrogels has been found to be slower in vivo than in vitro. The purpose of this study was to develop photocrosslinked alginate hydrogels with an increased range of biodegradation rates for more rapid in vivo biodegradation in regenerative medicine and bioactive factor delivery applications. Therefore, we oxidized alginate prior to methacrylation to change the uronate residue conformations to an open-chain adduct, which makes it more vulnerable to hydrolysis. Here, we demonstrate that the swelling behavior, degradation profiles, and storage moduli of photocrosslinked hydrogels formed from oxidized, methacrylated alginates (OMAs) are tunable by varying the degree of alginate oxidation. The OMA macromers and photocrosslinked OMA hydrogels exhibited cytocompatibility when cultured with human bone marrow-derived mesenchymal stem cells (hBMMSCs). In addition, hMSCs derived from bone marrow or adipose tissue photoencapsulated within these hydrogels remained viable, and their proliferation rate was a function of alginate oxidation level and initial hydrogel weight fraction. Oxidation permits a wider range of photocrosslinked OMA hydrogels physical properties, which may enhance these therapeutic materials’ utility in tissue engineering and other biomedical applications. PMID:22336294

  17. Alginate-based microencapsulation of retinal pigment epithelial cell line for cell therapy.

    Science.gov (United States)

    Wikström, Jonna; Elomaa, Matti; Syväjärvi, Heli; Kuokkanen, Johanna; Yliperttula, Marjo; Honkakoski, Paavo; Urtti, Arto

    2008-03-01

    The goals of this study were to evaluate human retinal pigment epithelial cell line (ARPE-19) for cell encapsulation and to optimize the alginate-based microencapsulation. We used immortalized ARPE-19 cells and the transfected sub-line that expresses secreted alkaline phosphatase (SEAP) reporter enzyme. Alginate was cross-linked with different divalent cations (Ca(2+), Ba(2+), Sr(2+) and combination of Ca(2+) and Ba(2+)), coated first with poly-l-lysine (PLL), and then with alginate. Microcapsules with different pore sizes and stability were generated. The pore size of the microcapsules was assessed by the release of encapsulated fluorescein isothiocyanate (FITC)-dextrans. The viability of the cells in the microcapsules was studied in vitro by assessing the secretion rates of SEAP and oxygen consumption by the cells. The best microcapsule morphology, durability and cellular viability were obtained with alginate microcapsules that were cross-linked with Ca(2+) and Ba(2+) ions and then coated with PLL and alginate. Based on FITC-dextran release these microcapsules have porous wall that enables the rapid contents release. The ARPE-19 cells maintained viability in the Ca(2+) and Ba(2+) cross-linked microcapsules for at least 110 days. The alginate microcapsules cross-linked with Ca(2+) and Ba(2+) have sufficiently large pore size for prolonged cell viability and for the release of secreted SEAP model protein (Mw 50 kDa; radius of gyration of 3 nm). ARPE-19 cells show long-term viability and protein secretion within alginate microcapsules cross-linked with Ca(2+) and Ba(2+). This combination may be useful in cell therapy.

  18. Drug release characterization and preparation of Ca-Alginate microparticle drug carrier using membrane emulsification method

    Energy Technology Data Exchange (ETDEWEB)

    You, Jin Oh; Park, Seong Bae; Park, Ham Yong; Haam, Seung Joo; Kim, Jung Hyun; Kim, Woo Sik [Dept. of Chemical Engineering, Yonsei University, Seoul (Korea)

    1999-10-01

    Conventional alginate bead has been limited to be used as a drug carrier because of its large size. To overcome the disadvantages of conventional large-size alginate drug beads, Ca-alginate microparticles were prepared using membrane emulsification method controlled with the sodium alginate concentration and the pressure of reactor. The optimal monodispersed microparticles were obtained with the concentration of 2 wt % alginate solution and the pressure of 0.4*10{sup 5} Pa. The mean size of our prepared microparticles was about 4 {gamma}m. As the drug solutions, lidocaine{center_dot}HCI(cationic), sodium salicylate(anionic) and 4-acetamidophenol(nonionic) were selected. These three different drugs were loaded in the drug carrier of prepared alginate microparticles. Drug releases were performed in the sodium phosphate buffers of pH 2 and pH 7 and ionic strength of 0.2. The release behavior with the variation of drug charge shoed that of the cationic drug release was retarded more than anionic one due to the ionic interaction between carboxyl group of alginates and positive charge of cationic drug. >From the comparison experiments of the buffers of pH 2 and pH 7, the release was much retarded at pH 2 buffer due to the ionic repulsive force or ionic attractive force between the carboxyl group and the hydroxy or sodium ion in the buffer. Conclusively, the usage of small-size pH sensitive microparticle as a drug carrier has a high potential for the application of drug delivery systems. 19 refs., 9 figs.

  19. The effect of disinfecting solutions on the dimensional stability of dental alginate impression materials.

    Science.gov (United States)

    Muzaffar, Danish; Braden, Michael; Parker, Sandra; Patel, Mangala P

    2012-07-01

    Dimensional changes occur in set dental alginate impression materials when immersed in disinfecting solutions. In this contribution the dimensional changes of two alginates in two disinfecting solutions, and for two specimen thicknesses, have been studied. The results were analyzed theoretically. The dimensional changes of two commercial alginates (Blueprint Cremix and Hydrogum), have been measured, in distilled water and two disinfecting solutions (Perform ID/sodium hypochlorite), using a traveling microscope, at 5 min intervals over a period of 1h. Samples of simple geometry have been studied, namely rectangular strips with thicknesses of 1.5 and 3mm, respectively. In all cases, both alginates continuously shrank with time, in the three immersion liquids, over the hour of measurement, indicating transfer of water from the alginate into the external water or disinfecting solution. The t(1/2) shrinkage plots were generally linear, but with an intercept on the t(1/2) axis, indicating the possibility of an initial expansion at very short times. In most cases, the ratios of slopes for both thicknesses were 1.33-1.54, in contrast to the theoretical value of 2. Perform ID however gave anomalous results for the 1.5mm thick samples. At 10 min their shrinkage was 1.34-1.72%, compared with -0.42% to 0.67% in the other two media. The effects of thickness observed were not in accord with simple Fickian theory because of the various ions diffusing into and out of the alginate. Moreover, the water content of the alginate decreased consequent on the cross-linking process. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  20. Preparation and evaluation of mucinated sodium alginate microparticles for oral delivery of insulin.

    Science.gov (United States)

    Builders, Philip F; Kunle, Olobayo O; Okpaku, Larry C; Builders, Modupe I; Attama, Anthony A; Adikwu, Michael U

    2008-11-01

    Effective oral insulin delivery remains a challenge to the pharmaceutical industry. In this study, insulin-loaded microparticles for oral delivery were prepared with mucin and sodium alginate combined at different ratios using a novel method based on polymer coacervation and diffusion filling. Some physical characteristics of the various insulin-loaded microparticles such as particle size, morphology and compressibility indices were determined. The microparticles were filled into hard gelatin capsules and the in vitro insulin release as well as the blood glucose reduction after oral administration to diabetic rabbits were determined. The microparticles formed were generally multi-particulate, discrete and free flowing. Before insulin loading, microparticles were round and smooth, becoming fluffier, less spherical and larger with rough and pitted surface after insulin loading. The insulin content of the microparticles increased with increase in their sodium alginate content. The various insulin-loaded microparticles prepared with the mucinated sodium alginate when encapsulated exhibited lag time before insulin release. The time taken to reach maximum insulin release from the various formulations varied with the mucin-sodium alginate ratio mix. The mean dissolution time of insulin from the microparticles prepared with sodium alginate, mucin, sodium alginate: mucin ratios of 1:1, 3:1 and 1:3 was 11.21+/-0.75, 3.3+/-0.42, 6.69+/-023, 8.52+/-0.95 and 3.48+/-0.65 (min.), respectively. The percentage blood glucose reduction for the subcutaneously administered insulin was significantly (porally administered insulin-loaded microparticles prepared with three parts of sodium alginate and one part of mucin after 5h was, however, equal to that produced by the subcutaneously administered insulin solution, an indication that it is an effective alternative for the delivery of insulin.

  1. SURVEY AND RESTORATION

    Directory of Open Access Journals (Sweden)

    C. Mileto

    2017-05-01

    Full Text Available In addition to the technological evolution over the last two centuries, survey has experienced two main conceptual leaps: the introduction of photography as a tool for an indiscriminate register for reality, and the shift from autographic to allographic survey, phenomena which can generate a distancing effect within the restoration process. Besides, this text presents the relationship between survey in its numerous forms and technologies (manual and semi-manual to more complex ones like scanner-laser and the restoration of the building, either for establishing a diagnosis, operating or valorizating, illustrating it with examples developed by the authors, as well as the criteria to be applied when documenting a building to be restored, irrespective of the means and technology available in each case.

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

    OpenAIRE

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

    2014-01-01

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

  3. Construction traditions and Restoration

    Directory of Open Access Journals (Sweden)

    B. Paolo Torsello

    2010-12-01

    Full Text Available In view of the physical and material incompatibility of many restoration works performed in the past, in recent years there has arisen a debate about the wisdom of retrieving old building traditions for the restoration process with a simple mechanical interpretation. Professor Torsello dissects the concept of tradition as regards its relationship with experience, science, history and production to discover an order of problems that affect the structure of our knowledge and whose origin resides in the radical changes that characterise modernity.

  4. Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

    Science.gov (United States)

    Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

    2018-01-01

    Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. 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.

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

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    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.

  7. Novel vanadyl complexes of alginate saccharides: synthesis, characterization, and biological activities.

    Science.gov (United States)

    Liu, Shengyi; Liu, Guangyang; Yi, Yuetao

    2015-05-05

    Vanadium compounds present many physiological functions. However, vanadium(IV) and (V) salts are difficult for gastrointestinal absorption and have strong side effects. Therefore organic oxovanadium compounds gain more attention. Vanadyl alginate polysaccharides (VAPS) and vanadyl alginate oligosaccharides (VAOS) were obtained from aqueous solutions of VOSO4 at pH 12. They were characterized by infrared spectroscopy, UV-vis spectroscopy and inductively coupled plasma-mass spectrometry (ICP-MS). The antioxidant activity of oxovanadium(IV) complexes was investigated in hydroxyl and DPPH radical scavenging systems in vitro. The results reveal that activities of VAPS and VAOS in the two systems were stronger than those of alginate polysaccharides (APS) and alginate oligosaccharides (AOS), respectively. In addition, VAPS and VAOS promoted significantly the antiproliferation of ligands of human hepatoma cell line BEL-7402. Oxovanadium(IV) complexes were potent inhibitors of protein tyrosine phosphatase 1B (PTP1B) with IC50 values in the range of 6.4-18.7μg/mL, indicated in biochemical assays. In addition, Vanadyl-alginate had no significant side effects on proliferation and viability of HL-7702 hepatic cells. In the future, they can be added to medicines and ease the growing threat that cancer and diabetes mellitus cause to human health. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Laminin-Alginate Beads as Preadipocyte Carriers to Enhance Adipogenesis In Vitro and In Vivo.

    Science.gov (United States)

    Hsueh, Yu-Sheng; Chen, Yo-Shen; Tai, Hao-Chih; Mestak, Ondrej; Chao, Sung-Chuan; Chen, Yen-Yu; Shih, Ying; Lin, Jung-Feng; Shieh, Ming-Jium; Lin, Feng-Huei

    2017-03-01

    The use of autologous fat grafting in breast reconstruction still requires optimization. Fat survival and calcification are the main issues that affect the outcomes of the procedure. In this study, a cell-based therapy utilizing laminin-alginate beads (LABs) as carriers was proposed to promote cell survival and adipogenesis by providing short-term physical support and facilitate nutrient diffusion of the implants. Laminin-modified alginate beads were fabricated by immobilizing laminin onto ring-opened alginate, used to encapsulate 3T3-L1 preadipocytes, and evaluated in vitro and in vivo. LABs as preadipocyte carriers showed better biocompatibility and stability than unmodified alginate beads. Preadipocytes in LABs had higher survival rate and enhanced adipogenesis than those in unmodified alginate beads. In vivo studies showed that LABs gradually degraded and the sites were replaced by newly formed fat tissues, and new blood vessels were also observed. 7T-MRI study mimicking clinical fat grafting showed that LABs carrying adipose stem cells improved the results of conventional fat grafts. Therefore, we believe that LABs represent promising cell carriers and can be potentially used for the reconstruction of breasts or other soft tissues in the future.

  9. Fabrication of large size alginate beads for three-dimensional cell-cluster culture

    Science.gov (United States)

    Zhang, Zhengtao; Ruan, Meilin; Liu, Hongni; Cao, Yiping; He, Rongxiang

    2017-08-01

    We fabricated large size alginate beads using a simple microfluidic device under a co-axial injection regime. This device was made by PDMS casting with a mold formed by small diameter metal and polytetrafluorothylene tubes. Droplets of 2% sodium alginate were generated in soybean oil through the device and then cross-linked in a 2% CaCl2 solution, which was mixed tween80 with at a concentration of 0.4 to 40% (w/v). Our results showed that the morphology of the produced alginate beads strongly depends on the tween80 concentration. With the increase of concentration of tween80, the shape of the alginate beads varied from semi-spherical to tailed-spherical, due to the decrease of interface tension between oil and cross-link solution. To access the biocompatibility of the approach, MCF-7 cells were cultured with the alginate beads, showing the formation of cancer cells clusters which might be useful for future studies.

  10. Encapsulation of DNA in macroscopic and nanosized calcium alginate gel particles.

    Science.gov (United States)

    Machado, Alexandra H E; Lundberg, Dan; Ribeiro, António J; Veiga, Francisco J; Miguel, Maria G; Lindman, Björn; Olsson, Ulf

    2013-12-23

    Calcium alginate beads, which are biodegradable and biocompatible, have been widely employed as delivery matrices for biomacromolecules. In the present work, the feasibility of encapsulation of DNA (which is used as a model biomacromolecule) in calcium alginate nanobeads (sub-200 nm size), prepared using a recently developed protocol based on the phase inversion temperature (PIT) emulsification method [Machado et al. Langmuir 2012, 28, 4131-4141], was assessed. The properties of the nanobeads were compared to those of the corresponding macroscopic (millimeter sized) calcium alginate beads. It was found that DNA, representing a relatively stiff and highly charged polyanion (thus like-charged to alginate), could be efficiently encapsulated in both nanosized and macroscopic beads, with encapsulation yields in the range of 77-99%. Complete release of DNA from the beads could be accomplished on dissolution of the gel by addition of a calcium-chelating agent. Importantly, the DNA was not denatured or fragmented during the preparation and collection of the nanobeads, which are good indicators of the mildness of the preparation protocol used. The calcium alginate nanobeads prepared by the herein utilized protocol thus show good potential to be used as carriers of sensitive biomacromolecules.

  11. 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.

  12. Encapsulation of allogeneic mesenchymal stem cells in alginate extends local presence and therapeutic function.

    Science.gov (United States)

    Leijs, M J; Villafuertes, E; Haeck, J C; Koevoet, W J; Fernandez-Gutierrez, B; Hoogduijn, M J; Verhaar, J A; Bernsen, M R; van Buul, G M; van Osch, G J

    2017-01-30

    Bone marrow derived mesenchymal stem cells (MSCs) have immunomodulatory and trophic capacities. For therapeutic application in local chronic inflammatory diseases, MSCs, preferably of allogeneic origin, have to retain immunomodulatory properties. This might be achieved by encapsulation of MSCs in a biomaterial that protects them from the host immune system. Most studies investigating the properties of MSCs for therapeutic application use short term cultures of cells in monolayer. Since the physical environment of MSCs can influence their functionality, we evaluated the feasibility of preserving the immunomodulatory properties of MSCs encapsulated in a three-dimensional alginate construct. After 5 weeks of implantation in immunocompetent rats, active allogeneic MSCs encapsulated in alginate were still detectable by Bio Luminescence Imaging and Magnetic Resonance Imaging of luciferase transduced and superparamagnetic iron oxide labelled MSCs. MSCs injected in saline were only detectable up to 1 week after injection. Moreover, the MSCs encapsulated in alginate responded to inflammatory stimuli similarly to MSCs in monolayer culture. In addition, MSC-alginate beads secreted immunomodulatory and trophic factors and inhibited T-cell proliferation after 30 d of in vitro culture. Our data indicate that allogeneic MSCs encapsulated in alginate persist locally and could act as an interactive immunomodulatory or trophic factor release system for several weeks, making this an interesting system to investigate for application in inflammatory disease conditions.

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

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    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.

  14. Paradigm Shift for Preparing Versatile M2+-Free Gels from Unmodified Sodium Alginate.

    Science.gov (United States)

    Pérez-Madrigal, Maria M; Torras, Joan; Casanovas, Jordi; Häring, Marleen; Alemán, Carlos; Díaz, David Díaz

    2017-09-11

    This manuscript describes a new route to prepare rapidly Ca2+-free hydrogels from unmodified sodium alginate by simply mixing with small organic molecules such as poly(carboxylic acid) compounds as cross-linker agents instead of classical divalent metal salts such as CaCl2. Dimethyl sulfoxide (DMSO) was also found to induce the rapid gelation of aqueous alginate solutions. The gelation process takes place at room temperature, and depending on the composition, gels with good thermal (90-100 °C) and mechanical properties compared to classical metal-containing analogs are obtained. DMSO-based gels showed remarkable self-supporting and thixotropic properties, which can be tuned by the biopolymer concentration. Furthermore, oxalic acid-based gels show superior elasticity than HCl, CaCl2 and DMSO-based gels. The possibility to prepare monoliths, beads, and films of these gels provide them with significant versatility. In particular, films made of alginate and oxalic acid show good potential as synergistic anticancer drug delivery carrier. Computational studies using both quantum mechanical and classical force-field methodologies reveal that hydrogen bonding networks between water and DMSO molecules located close to the alginate chains are responsible for the stability of DMSO-based gels. In contrast, the cohesion of oxalic acid-based gels is a consequence of the coexistence of multiple ionic associations involving oxalate, alginate, and Na+ counterions, which stabilize the system and keep all the interacting species grouped.

  15. The Synthesis of Alginate-Capped Silver Nanoparticles under Microwave Irradiation

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    Foliatini

    2015-03-01

    Full Text Available Synthesis of silver nanoparticles (Ag-NP was successfully performed within a few minutes by microwave irradiation of the precursor salt (AgNO3 and alginate mixed solution in one pot. Herein, alginate molecules acted as both a reducing and stabilizing agent for the preparation of the silver nanoparticles. The obtained nanoparticles were characterized by ultraviolet-visible (UV-Vis spectroscopy, particle size analysis (PSA, Fourier transform infrared spectroscopy (FTIR, and transmission electron microscopy (TEM. The pH and concentration ratio of the alginate/metal precursor salt greatly influenced the particle size and its distribution of Ag-NP. The higher the pH the higher the nucleation rate and the larger the electrostatic stabilization, while both of them were responsible for producing a smaller particle size and a narrower size distribution. A higher concentration ratio also yielded a smaller particle size and a narrower size distribution, but above the optimum ratio, the trend was conversely changed due to the reducing capability of the alginate, which was dominant above the optimum ratio, thus creating a high density of nuclei, allowing aggregation to occur. A lower ratio not only led to a higher tendency to produce larger particles, but also a higher probability of anisotropic particle shape formation due to the lack of reducing capability of the alginates.

  16. Release Behavior and Antibacterial Activity of Chitosan/Alginate Blends with Aloe vera and Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Luisa Fernanda Gómez Chabala

    2017-10-01

    Full Text Available Aloe vera is a perennial plant employed for medical, pharmaceutical and cosmetic purposes that is rich in amino acids, enzymes, vitamins and polysaccharides, which are responsible for its therapeutic properties. Incorporating these properties into a biopolymer film obtained from alginate and chitosan allowed the development of a novel wound dressing with antibacterial capacity and healing effects to integrate the antibacterial capacity of silver nanoparticles with the healing and emollient properties of Aloe vera gel. Three alginate-chitosan matrices were obtained through blending methods using different proportions of alginate, chitosan, the Aloe vera (AV gel and silver nanoparticles (AgNps, which were incorporated into the polymeric system through immersion methods. Physical, chemical and antibacterial characteristics were evaluated in each matrix. Interaction between alginate and chitosan was identified using the Fourier transform infrared spectroscopy technique (FTIR, porosity was studied using scanning electron microscopy (SEM, swelling degree was calculated by difference in weight, Aloe vera gel release capacity was estimated by applying a drug model (Peppas and finally antibacterial capacity was evaluated against S. Aureus and P. aeruginosa. Results show that alginate-chitosan (A (1:3 Chit 1/Alg 1; B (1:3 Chit 1.5/Alg 1 and C (3:1 Chit 1/Alg 1/B12 matrices with Aloe vera (AV gel and silver nanoparticles (AgNps described here displayed antibacterial properties and absorption and Aloe vera release capacity making it a potential wound dressing for minor injuries.

  17. 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.

  18. Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus

    Directory of Open Access Journals (Sweden)

    SUSIANY LOPES

    2017-08-01

    Full Text Available ABSTRACT This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM, moisture content, Fourier Transform Infrared Spectrometry (FTIR, thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.

  19. 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.

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

    Science.gov (United States)

    Montanucci, Pia; Terenzi, Silvia; Pennoni, Ilaria; Basta, Giuseppe; Calafiore, Riccardo

    2015-01-01

    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. PMID:26078974

  1. 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.

  2. Alginate based nanocomposite for microencapsulation of probiotic: Effect of cellulose nanocrystal (CNC) and lecithin.

    Science.gov (United States)

    Huq, Tanzina; Fraschini, Carole; Khan, Avik; Riedl, Bernard; Bouchard, Jean; Lacroix, Monique

    2017-07-15

    Probiotic (Lactobacillus rhamnosus ATCC 9595) was encapsulated in alginate-CNC-lecithin microbeads to produce nutraceutical microcapsules. Addition of CNC and lecithin in alginate microbeads (ACL-1) improved the viability of L. rhamnosus during gastric passage and storage. The compression strength of the freeze-dried ACL-1 microbeads improved 40% compared to alginate microbeads alone. Swelling studies revealed that addition of CNC and lecithin in alginate microbeads decreased (around 47%) the gastric fluid absorption but increased the dissolution time by 20min compared to alginate microbeads (A-0). During transition through the gastric passage, the viability of L. rhamnosus in dried ACL-1 microbeads was increased 37% as compared to A-0 based beads. At 25 and 4°C storage conditions, the viability of L. rhamnosus encapsulated in ACL-1 microbeads decreased by 1.23 and 1.08 log respectively, whereas the encapsulation with A-0 microbeads exhibited a 3.17 and 1.93 log reduction respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Release Behavior and Antibacterial Activity of Chitosan/Alginate Blends with Aloe vera and Silver Nanoparticles.

    Science.gov (United States)

    Gómez Chabala, Luisa Fernanda; Cuartas, Claudia Elena Echeverri; López, Martha Elena Londoño

    2017-10-24

    Aloe vera is a perennial plant employed for medical, pharmaceutical and cosmetic purposes that is rich in amino acids, enzymes, vitamins and polysaccharides, which are responsible for its therapeutic properties. Incorporating these properties into a biopolymer film obtained from alginate and chitosan allowed the development of a novel wound dressing with antibacterial capacity and healing effects to integrate the antibacterial capacity of silver nanoparticles with the healing and emollient properties of Aloe vera gel. Three alginate-chitosan matrices were obtained through blending methods using different proportions of alginate, chitosan, the Aloe vera (AV) gel and silver nanoparticles (AgNps), which were incorporated into the polymeric system through immersion methods. Physical, chemical and antibacterial characteristics were evaluated in each matrix. Interaction between alginate and chitosan was identified using the Fourier transform infrared spectroscopy technique (FTIR), porosity was studied using scanning electron microscopy (SEM), swelling degree was calculated by difference in weight, Aloe vera gel release capacity was estimated by applying a drug model (Peppas) and finally antibacterial capacity was evaluated against S. Aureus and P. aeruginosa. Results show that alginate-chitosan (A (1:3 Chit 1/Alg 1); B (1:3 Chit 1.5/Alg 1) and C (3:1 Chit 1/Alg 1/B12)) matrices with Aloe vera (AV) gel and silver nanoparticles (AgNps) described here displayed antibacterial properties and absorption and Aloe vera release capacity making it a potential wound dressing for minor injuries.

  4. The effectiveness of alginates to reduce the transfer of radiostrontium to the milk of dairy goats

    Energy Technology Data Exchange (ETDEWEB)

    Beresford, N.A. [Institute of Terrestrial Ecology, Merlewood Research Station, Grange-over-Sands, Cumbria (United Kingdom); Mayes, R.W.; MacEachern, P.J. [The Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen (United Kingdom); Dodd, B.A. [Institute of Terrestrial Ecology, Merlewood Research Station, Grange-over-Sands, Cumbria (United Kingdom); Lamb, C.S. [The Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen (United Kingdom)

    1999-05-01

    In the event of a nuclear accident the radiation dose to human populations arising from radiostrontium ingested as contaminated milk is a major cause of concern. We report a study to determine if calcium alginate incorporated into the diet can be used as an effective countermeasure to reduce radiostrontium transfer to the milk of dairy goats. When Ca-alginate was included into a pelleted ration at 5% dry weight the transfer of radiostrontium to the milk of the goats was reduced by approximately 50%. No effects on diet palatability or the absorption of iron or calcium were observed. Ca-alginate was readily fermentable and hence its potential binding capacity is likely to be reduced in ruminants compared to monogastrics. The Ca-alginate also supplied additional calcium to the diet in an amount which may explain the observed reduction in radiostrontium transfer to milk. Therefore, currently, we cannot be certain if the effect we observed was due to alginate or calcium. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. The effect of ionotropic gelation residence time on alginate cross-linking and properties.

    Science.gov (United States)

    Patel, Mitulkumar A; AbouGhaly, Mohamed H H; Schryer-Praga, Jacqueline V; Chadwick, Keith

    2017-01-02

    The ability to engineer biocompatible polymers with controllable properties is highly desirable. One such approach is to cross-link carbohydrate polymers using ionotropic gelation (IG). Previous studies have investigated the effect of curing time on alginate cross-linking. Herein, we discuss a novel study detailing the effect of IG residence time (IGRT) on the cross-linking of alginate with calcium ions (Ca2+) along with water migration (syneresis) and their subsequent impact on the pharmaceutical properties of alginate particles. IGRT was shown to have a significant effect on particle size, porosity, density, mechanical strength and swelling of calcium alginate particles as well as drug release mechanism. Furthermore, we describe a novel application of electron dispersive spectroscopy (EDS), in conjunction with Fourier Transform- infra red (FT-IR) spectroscopy, to analyze and monitor the changes in Ca2+ concentration during cross-linking. A simple procedure to determine the concentration and distribution of the surface and internal Ca2+ involved in alginate cross-linking was successfully developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Characterization of a Long-Lived Alginate Lyase Derived from Shewanella Species YH1

    Directory of Open Access Journals (Sweden)

    Hisashi Yagi

    2017-12-01

    Full Text Available Polysaccharides from seaweeds are widely used in various fields, including the food, biomedical material, cosmetic, and biofuel industries. Alginate, which is a major polysaccharide in brown algae, and the products of its degradation (oligosaccharides have been used in stabilizers, thickeners, and gelling agents, especially in the food industry. Discovering novel alginate lyases with unique characteristics for the efficient production of oligosaccharides may be relevant for the food and pharmaceutical fields. In this study, we identified a unique alginate lyase derived from an alginate-utilizing bacterium, Shewanella species YH1. The recombinant enzyme (rAlgSV1-PL7 was produced in an Escherichia coli system and it was classified in the Polysaccharide Lyase family 7. The optimal temperature and pH for rAlgSV1-PL7 activity were around 45 °C and 8, respectively. Interestingly, we observed that rAlgSV1-PL7 retained over 80% of its enzyme activity after incubation at 30 °C for at least 20 days, indicating that rAlgSV1-PL7 is a long-lived enzyme. Moreover, the degradation of alginate by rAlgSV1-PL7 produced one to four sugars because of the broad substrate specificity of this enzyme. Our findings suggest that rAlgSV1-PL7 may represent a new commercially useful enzyme.

  8. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Alginate immobilized enrichment culture for atrazine degradation in soil and water system.

    Science.gov (United States)

    Kumar, Anup; Nain, Lata; Singh, Neera

    2017-04-03

    An atrazine degrading enrichment culture, a consortium of bacteria of genus Bacillus along with Pseudomonas and Burkholderia, was immobilized in sodium alginate and was used to study atrazine degradation in mineral salts medium (MSM), soil and wastewater effluent. Sodium alginate immobilized consortium, when stored at room temperature (24 ± 5°C), was effective in degrading atrazine in MSM up to 90 days of storage. The survival of bacteria in alginate beads, based on colony formation unit (CFU) counts, suggested survival up to 90 days and population counts decreased to 1/5 th on 120 days. Comparison of atrazine degrading ability of the freely suspended enrichment culture and immobilized culture suggested that the immobilized culture took longer time for complete degradation of atrazine as a lag phase of 2 days was observed in the MSM inoculated with alginate immobilized culture. The free cells resulted in complete degradation of atrazine within 6 days, while immobilized cells took 10 days for 100% atrazine degradation. Further, immobilized cultures were able to degrade atrazine in soil and wastewater effluent. Alginate beads were stable and effective in degrading atrazine till 3rd transfer and disintegrated thereafter. The study suggested that immobilized enrichment culture, due to its better storage and application, can be used to degrade atrazine in soil water system.

  10. 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.

  11. Adhesive restorations replacing cusps

    NARCIS (Netherlands)

    Fennis, W.M.M.; Kuijs, R.H.

    2005-01-01

    This study addressed a clinical problem in dentistry. The problem concerns the occurrence of complete fracture of a cusp of premolars with an existing Class II restoration, and the required treatment after this cusp fracture. The traditional treatment in these cases is the making of a crown. Crown

  12. Restoring Forested Wetland Ecosystems

    Science.gov (United States)

    John A. Stanturf; Emile S. Gardiner; Melvin L. Warren

    2003-01-01

    Forests as natural systems are intrinsically linked to the sustainability of fresh-water systems. Efforts worldwide to restore forest ecosystems seek to counteract centuries of forest conversion to agriculture and other uses. Afforestation, the practice of regenerating forests on land deforested for agriculture or other uses, is occurring at an intense pace in the...

  13. Realistic restoration targets

    Science.gov (United States)

    Melissa Thomas-Van Gundy; Robert. Whetsell

    2016-01-01

    These reference ecosystems and historic range of variability may be hard to define or determine, but accepted methods can include cultural evidence such as written descriptions, oral histories, maps and photographs, and survey records (Egan and Howell 2001). Another tactic is to focus on restoring species composition (such as returning the American chestnut) and...

  14. Restoration in South Africa

    CSIR Research Space (South Africa)

    Blignaut, J

    2010-01-01

    Full Text Available Restoration can provide a wide range of direct and indirect benefits to society. However, there are very few projects that have attempted to properly quantify those benefits and present them in such a way that society is motivated to invest...

  15. 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.

  16. Investigation of cell viability and morphology in 3D bio-printed alginate constructs with tunable stiffness.

    Science.gov (United States)

    Shi, Pujiang; Laude, Augustinus; Yeong, Wai Yee

    2017-04-01

    In this article, mouse fibroblast cells (L929) were seeded on 2%, 5%, and 10% alginate hydrogels, and they were also bio-printed with 2%, 5%, and 10% alginate solutions individually to form constructs. The elastic and viscous moduli of alginate solutions, their interior structure and stiffness, interactions of cells and alginate, cell viability, migration and morphology were investigated by rheometer, MTT assay, scanning electron microscope (SEM), and fluorescent microscopy. The three types of bio-printed scaffolds of distinctive stiffness were prepared, and the seeded cells showed robust viability either on the alginate hydrogel surfaces or in the 3D bio-printed constructs. Majority of the proliferated cells in the 3D bio-printed constructs weakly attached to the surrounding alginate matrix. The concentration of alginate solution and hydrogel stiffness influenced cell migration and morphology, moreover the cells formed spheroids in the bio-printed 10% alginate hydrogel construct. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1009-1018, 2017. © 2017 Wiley Periodicals, Inc.

  17. 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

  18. Physical, mechanical, and barrier properties of sodium alginate/gelatin emulsion based-films incorporated with canola oil

    Science.gov (United States)

    Syarifuddin, A.; Hasmiyani; Dirpan, A.; Mahendradatta, M.

    2017-12-01

    The development of mixed emulsion-based films formed by sodium alginate/gelatin incorporated with canola oil can offer particular properties such as water vapor barrier properties. The different ratios of sodium alginate/gelatin and sodium alginate/gelatin emulsion-based films incorporated with canola oil were developed and their effects on films’ physical, mechanical and barrier properties were assessed. Here we set out to examine whether canola oil addition and different ratio of sodium alginate/gelatin modified physical, mechanical, and barrier properties of films. To do so, the films were prepared by vary the ratio of sodium alginate/gelatin (2.5, 1, 0.5). Canola oil addition induced changes in moisture content, thickness, solubility, water vapor transmission rate (WVTR), percent elongation at break (palginate to gelatin induced change the mechanical properties of films. The reduction of sodium alginate to gelatin decreased the tensile strength of both films. Improved values of WVTR, tensile strength and solubility at break were observed when the ratio of sodium alginate/gelatin emulsion film incorporated with canola oil was 2.5. Therefore, different ratio of sodium alginate/gelatin incorporated with canola oil can be used to tailor emulsion films with enhanced water vapor barrier and mechanical properties.

  19. Effective removal of alginate-poly-L-lysine microcapsules from pancreatic islets by use of trypsin-EDTA

    NARCIS (Netherlands)

    de Groot, M; Leuvenink, HGD; Fekken, S; Schuurs, TA; van Schilfgaarde, R; KEIZER, J

    2003-01-01

    Although the transplantation of alginate-poly-L-lysine-alginate encapsulated islets of Langerhans usually is successful, graft survival is still limited. Molecular analysis by RT-PCR of the encapsulated islets may provide insight into the mechanisms that affect islets during graft failure. However,

  20. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Experimental microencapsulation of porcine and rat pancreatic islet cells with air-driven droplet generator and alginate.

    Science.gov (United States)

    Koo, S K; Kim, S C; Wee, Y M; Kim, Y H; Jung, E J; Choi, M Y; Park, Y H; Park, K T; Lim, D G; Han, D J

    2008-10-01

    Transplantation of microencapsulated islets is proposed as an ideal therapy for the treatment of type 1 diabetes mellitus without immunosuppression. This strategy is based on the principle that foreign cells are protected from the host immune system by an artificial membrane. The aim of this study was to establish an ideal condition of microencapsulation using an air-driven droplet generator and alginate in vitro. The optimal conditions for islet encapsulation were an alginate inflow rate of 10 mL/h, CO2 flow rate of 2.0 L/min in a concentration of 2% alginate. For 2.5% alginate, the alginate inflow rate of 20 mL/h, CO2 flow rate 3.0 L/min was ideal; alginate inflow rate of 40 mL/h, CO2 flow rate of 4.0 L/min showed good microcapsules at 3% alginate. Viability of encapsulated islets was greater than 90%. In terms of insulin secretion, encapsulated islets secreted insulin in response to glucose in static culture medium. However, there was no normal response to low or high glucose challenge with a stimulation index less than 2.0. Microencapsulation of pig islets was successfully performed with air-driven droplet generator and alginate in vitro. Further studies about biocompatibility and glucose control in vivo may provide a useful tool for treatment of patients with diabetes mellitus.

  2. 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

    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

  3. Optimized Preparation of Carboxymethyl Chitosan/Sodium Alginate Hemostatic Microcapsule

    Science.gov (United States)

    Hu, Z.; Guang, J.; Lu, S. T.; Chen, Y.; Li, S. D.; Cai, Y.

    2017-12-01

    In order to prepare and optimize a novel and efficient hemostatic material, a hemostatic microcapsule was prepared by piercing granulation technique with carboxymethyl chitosan and sodium alginate as substrate materials. Three factors in the process (mass percentage of carboxymethyl chitosan, concentration of calcium chloride and pH value of cross-linking system) were investigated through single-factor experiment to explore the effect of experimental factors on water absorbance of hemostatic microcapsule. On the basis of single-factor experiment, orthogonal experiment was conducted to optimize the preparation process of hemostatic microcapsule. Optimized process conditions were obtained as following: mass percentage of carboxymethyl chitosan 25%, concentration of calcium chloride 3.0% and cross-linking system pH=9.0. Microcapsule with normal morphology, uniform particle size, good dispersibility and porous structure was prepared under these conditions. And its water absorbance ratio reached 16.17. In vitro procoagulant test showed that the microcapsule had satisfactory procoagulant effect and was in a dose dependent manner.

  4. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Science.gov (United States)

    López-Cacho, J. M.; González-R, Pedro L.; Talero, B.; Rabasco, A. M.; González-Rodríguez, M. L.

    2012-01-01

    Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. A L 18 Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t 50% and AUC), swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value. PMID:22645438

  5. Removal of organic dyes by magnetic alginate beads.

    Science.gov (United States)

    Rocher, Vincent; Siaugue, Jean-Michel; Cabuil, Valérie; Bee, Agnès

    2008-02-01

    This study deals with the development of a clean and safe process for water pollution remediation. We have synthesized a magnetic adsorbent in order to develop a solid-phase extraction process assisted by a magnetic field. To follow an 'ecoconception' approach, magnetic beads containing magnetic nanoparticles and activated carbon are prepared with a biopolymer extracted from algae, sodium alginate. The use of renewable bioresources of low cost and those disposable in large amount allows the development of a product with a low impact on the environment. The adsorption properties of activated carbon and magnetic properties of iron oxide nanoparticles are combined to produce an interesting magnetic composite. Synthesis and characterization of the magnetic beads have been reported. Their adsorption capacity was investigated by measuring the removal of two dyes (methylene blue and methyl orange) of different charges from aqueous solutions. The efficiency of the beads has been compared with that of non-encapsulated activated carbon. The effects of initial dye concentration, pH and calcium content of the beads have been studied. Adsorption kinetics experiments have been carried out and the data have been well fitted by a pseudo-second-order equation.

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

    Directory of Open Access Journals (Sweden)

    Ana Carolina Vale Campos Lisboa

    2007-12-01

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

  7. 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.

  8. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Directory of Open Access Journals (Sweden)

    J. M. López-Cacho

    2012-01-01

    Full Text Available Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. A L18 Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t50% and AUC, swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value.

  9. Micellar electrokinetic capillary chromatography determination of alginic acid in pharmaceutical formulations after treatment with alginate lyase and UV detection.

    Science.gov (United States)

    Volpi, Nicola

    2008-09-01

    A new highly specific and sensitive capillary electrophoresis method (electrokinetic chromatography with SDS) for the determination of the total alginic acid (AA) content in pharmaceutical formulations is described by means of capillary electrophoresis at 230 nm after treatment with alginate lyase [4.2.2.3] and separation of unsaturated products, Delta-oligomers (DeltaHexA-[HexA](n)), in particular, DP3 (DeltaHexA-HexA-HexA) and DP4 (DeltaHexA-HexA-HexA-HexA). Using a buffer constituted with 10 mM sodium borate and 50 mM SDS at pH 9.0, micellar electrokinetic capillary chromatography was able to determine with very high resolution the AA Delta-oligomers produced by the action of the lyase (mainly DP3 and DP4) as one single species. The intra- and inter-day variations (CV%) were between 6.3 and 9.1 for migration time and between 2.5 and 5.7 for peak area, respectively. The calibration curve showed good linearity for the examined concentration range (60-360 ng) with an average correlation coefficient greater than 0.980. The lowest detection limit and the lowest quantitation limit of the method were 15 ng (0.25 mg/mL) and 40 ng (0.67 mg/mL), respectively. The intra- and inter-day variations in terms of CV% were 5.5 and 8.6%, respectively, and the intra- and inter-day accuracy was estimated to range from 4.1 to 8.9%, while the percent recoveries of AA were calculated to be 102, 97 and 93% for different AA amounts. Variations in temperatures, voltage and buffer composition in comparison with adopted conditions within a 10% limit do not modify the electrophoresis results. The evaluation of AA was performed in both solid and liquid pharmaceutical formulations also in the presence of other ingredients, in particular, aluminium, sodium and potassium bicarbonate, and emulsifying and flavouring agents. The quantitative results obtained were 101.2+/-3.4% of AA content in tablets and 98.4+/-2.8% in liquid formulation, in total conformity with the label claims.

  10. Effects of process variables on the encapsulation of oil in ca-alginate capsules using an inverse gelation technique.

    Science.gov (United States)

    Abang, Sariah; Chan, Eng-Seng; Poncelet, Denis

    2012-01-01

    The objective of this study was to investigate the effects of process variables on the encapsulation of oil in a calcium alginate membrane using an inverse gelation technique. A dispersion of calcium chloride solution in sunflower oil (water-in-oil emulsion) was added dropwise to the alginate solution. The migration of calcium ions to the alginate solution initiates the formation of a ca-alginate membrane around the emulsion droplets. The membrane thickness of wet capsules and the elastic modulus of dry capsules increased following first-order kinetics with an increasing curing time. An increase in the calcium chloride concentration increased the membrane thickness of wet capsules and the elastic modulus of dry capsules. An increase in the alginate concentration decreased the mean diameter of wet capsules but increased the elastic modulus of dry capsules.

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

    Energy Technology Data Exchange (ETDEWEB)

    Badita, C. R., E-mail: ramona@tandem.nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); University of Bucharest, Faculty of Physics, Atomiştilor 405, CP MG - 11, RO – 077125, Bucharest-Magurele (Romania); Aranghel, D., E-mail: daranghe@nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Extreme Light Intrastructure Nuclear Physics (ELI-NP), Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest (Romania); Radulescu, A. [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science, 85747 Garching (Germany); Anitas, E. M. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)

    2016-03-25

    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 Ca{sup 2+} 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 Ca{sup 2+} 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.

  12. Papahanaumokuakea - Laysan Island Restoration 2010

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Goal of the Laysan Island Restoration is to restore Laysan to a "Pristine" state which would require minimal monitoring and habitat for Endemic Endangered...

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes......–Einstein effective molecular radius. Because the alginate bead size was not constant during the release experiments, it was hypothesised that in addition to the diffusional mass transfer, a non-negligible convective flow of liquid in or out of the beads was present due to swelling or shrinkage, respectively...... convective flow in the numerical model, release could be described more accurately. The numerical model was able to describe the release  characteristics from both shrinking, swelling, and non-swelling alginate beads. To evaluate the effect of bead swelling on the protein release rate, a swelling modulus...

  14. 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

    A thin alginate layer induced on the surface of a commercial polysulfone membrane was used as a matrix for noncovalent immobilization of enzymes. Despite the expected decrease of flux across the membrane resulting from the coating, the initial hypothesis was that such a system should allow high...... 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...... setup (without alginate) where only 10.8% (6.9 μg/cm2) enzyme was loaded, with less than 5% conversion. Such conversion increased to 60% when polyethylene glycol (PEG) was added during the construction of the gel layer, as a strategy to increase flux. No enzyme leakage was observed for both cases (with...

  15. Activation Mechanism and Cellular Localization of Membrane-Anchored Alginate Polymerase in Pseudomonas aeruginosa.

    Science.gov (United States)

    Moradali, M Fata; Ghods, Shirin; Rehm, Bernd H A

    2017-05-01

    The exopolysaccharide alginate, produced by the opportunistic human pathogen Pseudomonas aeruginosa, confers a survival advantage to the bacterium by contributing to the formation of characteristic biofilms during infection. Membrane-anchored proteins Alg8 (catalytic subunit) and Alg44 (copolymerase) constitute the alginate polymerase that is being activated by the second messenger molecule bis-(3', 5')-cyclic dimeric GMP (c-di-GMP), but the mechanism of activation remains elusive. To shed light on the c-di-GMP-mediated activation of alginate polymerization in vivo, an in silico structural model of Alg8 fused to the c-di-GMP binding PilZ domain informed by the structure of cellulose synthase, BcsA, was developed. This structural model was probed by site-specific mutagenesis and different cellular levels of c-di-GMP. Results suggested that c-di-GMP-mediated activation of alginate polymerization involves amino acids residing at two loops, including H323 (loop A) and T457 and E460 (loop B), surrounding the catalytic site in the predicted model. The activities of the respective Alg8 variants suggested that c-di-GMP-mediated control of substrate access to the catalytic site of Alg8 is dissimilar to the known activation mechanism of BcsA. Alg8 variants responded differently to various c-di-GMP levels, while MucR imparted c-di-GMP for activation of alginate polymerase. Furthermore, we showed that Alg44 copolymerase constituted a stable dimer, with its periplasmic domains required for protein localization and alginate polymerization and modification. Superfolder green fluorescent protein (GFP) fusions of Alg8 and Alg44 showed a nonuniform, punctate, and patchy arrangement of both proteins surrounding the cell. Overall, this study provides insights into the c-di-GMP-mediated activation of alginate polymerization while assigning functional roles to Alg8 and Alg44, including their subcellular localization and distribution.IMPORTANCE The exopolysaccharide alginate is an

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

    DEFF Research Database (Denmark)

    Cao, Bao; Christophersen, Lars; Kolpen, Mette

    2016-01-01

    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...

  17. Oil encapsulation techniques using alginate as encapsulating agent: applications and drawbacks.

    Science.gov (United States)

    Martins, Evandro; Poncelet, Denis; Rodrigues, Ramila Cristiane; Renard, Denis

    2017-12-01

    Oils are used in agriculture, nutrition, food and cosmetics; however, these substances are oxidisable and may readily lose their properties. To reduce their degradation or to mask certain undesirable aspects, one strategy consists in encapsulating the oil in inert structures (capsules). The capsules are classified according to the morphology, the number of cores and size, can be produced by several techniques: jet-cutting, vibrating jet, spray-drying, dispersion and milli-microfluidic. Among the polymers used as a membrane in the capsules, alginates are used in oil encapsulation because of their high gelling capacity, biocompatibility and low toxicity. In the presence of calcium ions, the alginate macromolecules crosslink to form a three-dimensional network called hydrogel. The oil encapsulation using alginate as encapsulating material can be carried out using technologies based on the external, internal or inverse gelation mechanisms. These capsules can found applications in areas as cosmetics, textile, foods and veterinary, for example.

  18. Encapsulation and culture of mammalian cells including corneal cells in alginate hydrogels.

    Science.gov (United States)

    Hunt, Nicola C; Grover, Liam M

    2013-01-01

    The potential of cell therapy for the regeneration of diseased and damaged tissues is now widely -recognized. As a consequence there is a demand for the development of novel systems that can deliver cells to a particular location, maintaining viability, and then degrade at a predictable rate to release the cells into the surrounding tissues. Hydrogels have attracted much attention in this area, as the hydrogel structure provides an environment that is akin to that of the extracellular matrix. One widely investigated hydrogel is alginate, which has been used for cell encapsulation for more than 30 years. Alginate gels have the potential to be used as 3D cell culture systems and as prosthetic materials, both are applied to regeneration of the cornea. Here, we describe an alginate-based process that has been used for encapsulation of mammalian cells including corneal cells, with high levels of viability, and which allows subsequent retrieval of cell cultures for further characterization.

  19. Microencapsulation in alginate and chitosan microgels to enhance viability of Bifidobacterium longum for oral delivery

    Directory of Open Access Journals (Sweden)

    Timothy W. Yeung

    2016-04-01

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

  20. Alginate-based microcapsules with galactosylated chitosan internal for primary hepatocyte applications.

    Science.gov (United States)

    Lou, Ruyun; Xie, Hongguo; Zheng, Huizhen; Ren, Ying; Gao, Meng; Guo, Xin; Song, Yizhe; Yu, Weiting; Liu, Xiudong; Ma, Xiaojun

    2016-12-01

    Alginate-galactosylated chitosan/polylysine (AGCP) microcapsules with excellent stability and high permeability were developed and employed in primary hepatocyte applications. The galactosylated chitosan (GC), synthesized via the covalent coupling of lactobionic acid (LA) with low molecular weight and water-soluble chitosan (CS), was ingeniously introduced into the core of alginate microcapsules by regulating the pH of gelling bath. The internal GC of the microcapsules simultaneously provided a large number of binding sites for the hepatocytes and further promoted the hepatocyte-matrix interactions via the recognition of asialoglycoprotein receptors (ASGPRs) on the hepatocyte surface, and afforded the AGCP microcapsules an excellent stability via the electrostatic interactions with alginate. As a consequence, primary hepatocytes in AGCP microcapsules demonstrated enhanced viability, urea synthesis, albumin secretion, and P-450 enzyme activity, showing great prospects for hepatocyte applications in microcapsule system. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mata, Y.N. [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Blazquez, M.L. [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)], E-mail: mlblazquez@quim.ucm.es; Ballester, A.; Gonzalez, F.; Munoz, J.A. [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-04-30

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

  2. Review article: alginate-raft formulations in the treatment of heartburn and acid reflux.

    Science.gov (United States)

    Mandel, K G; Daggy, B P; Brodie, D A; Jacoby, H I

    2000-06-01

    Alginate-based raft-forming formulations have been marketed word-wide for over 30 years under various brand names, including Gaviscon. They are used for the symptomatic treatment of heartburn and oesophagitis, and appear to act by a unique mechanism which differs from that of traditional antacids. In the presence of gastric acid, alginates precipitate, forming a gel. Alginate-based raft-forming formulations usually contain sodium or potassium bicarbonate; in the presence of gastric acid, the bicarbonate is converted to carbon dioxide which becomes entrapped within the gel precipitate, converting it into a foam which floats on the surface of the gastric contents, much like a raft on water. Both in vitro and in vivo studies have demonstrated that alginate-based rafts can entrap carbon dioxide, as well as antacid components contained in some formulations, thus providing a relatively pH-neutral barrier. Several studies have demonstrated that the alginate raft can preferentially move into the oesophagus in place, or ahead, of acidic gastric contents during episodes of gastro-oesophageal reflux; some studies further suggest that the raft can act as a physical barrier to reduce reflux episodes. Although some alginate-based formulations also contain antacid components which can provide significant acid neutralization capacity, the efficacy of these formulations to reduce heartburn symptoms does not appear to be totally dependent on the neutralization of bulk gastric contents. The strength of the alginate raft is dependant on several factors, including the amount of carbon dioxide generated and entrapped in the raft, the molecular properties of the alginate, and the presence of aluminium or calcium in the antacid components of the formulation. Raft formation occurs rapidly, often within a few seconds of dosing; hence alginate-containing antacids are comparable to traditional antacids for speed of onset of relief. Since the raft can be retained in the stomach for several

  3. Preparation of bismuth titanate/calcium alginate composite bead and its photocatalytic degradation of dye pollutants

    Science.gov (United States)

    Gan, Huihui; Dong, Nanyang; Lu, Linxiao; Fu, Yan; Zhang, Huining; Qian, Yongxin; Zhang, Kefeng; Jin, Huixia

    2017-08-01

    In this study, the bismuth titanate/calcium alginate composite bead was synthesized by immobilizing bismuth titanate Bi4Ti3O12 particles into 1.5% sodium alginate (SA) matrix. The Bi4Ti3O12 particles were characterized by X-ray diffraction (XRD). The photocatalytic activity for the degradation of dye Rhodamine B in solution by as-prepared bismuth titanate/calcium alginate composite bead was investigated. The as-prepared composite beads CA/BTO-700 exhibited best photocatalytic efficiency for the degradation of RhB compared with CA/BTO-800 and CA/BTO-900 under simulated solar light. After 4 cycles in photocatalytic degradation of RhB, the degradation rate of the CA/BTO-700 nearly remained unchanged.

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

    Directory of Open Access Journals (Sweden)

    Koshi Saito

    2014-01-01

    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.

  5. Removal of two organophosphate pesticides by a bacterial consortium immobilized in alginate or tezontle.

    Science.gov (United States)

    Yañez-Ocampo, Gustavo; Sanchez-Salinas, Enrique; Jimenez-Tobon, Gloria Alicia; Penninckx, Michel; Ortiz-Hernández, María Laura

    2009-09-15

    In order to remove methyl-parathion (MP) and tetrachlorvinphos (TCF), a bacterial consortium was immobilized with two supports consisting of alginate beads or stones of tezontle colonized by biofilm. Removal kinetics were recorded for suspended and immobilized consortium using a mineral salt medium supplemented with MP and TCF at 25mg/L and with 0.1% (w/v) glucose as a co-substrate. The viability of the consortium cultivated in suspension was maintained for 6 days, whereas the viability of the consortium immobilized in alginate and tezontle supports was maintained for up to 11 and 13 days, respectively. Growth was enhanced when using glucose as a co-substrate. The percentage of MP removed was significantly higher (alpha=0.05) when consortium was immobilized in alginate beads and biofilm on tezontle as compared to suspension culture.

  6. Microencapsulation of Ginger Volatile Oil Based on Gelatin/Sodium Alginate Polyelectrolyte Complex.

    Science.gov (United States)

    Wang, Lixia; Yang, Shiwei; Cao, Jinli; Zhao, Shaohua; Wang, Wuwei

    2016-01-01

    The coacervation between gelatin and sodium alginate for ginger volatile oil (GVO) microencapsulation as functions of mass ratio, pH and concentration of wall material and core material load was evaluated. The microencapsulation was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and thermal gravimetric analysis (TGA). SEM and FT-IR studies indicated the formation of polyelectrolyte complexation between gelatin and sodium alginate and successful encapsulation of GVO into the microcapsules. Thermal property study showed that the crosslinked microparticles exhibited higher thermal stability than the neat GVO, gelatin, and sodium alginate. The stability of microencapsulation of GVO in a simulated gastric and an intestinal situation in vitro was also studied. The stability results indicated that the release of GVO from microcapsules was much higher in simulated intestinal fluid, compared with that in simulated-gastric fluid.

  7. 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

    -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...... that the production of alginate is not critical for biofilm formation. Observation over a period of 5 days indicated a three-stage development pattern consisting of initiation, establishment and maturation. Furthermore, this study showed that phenotypically distinguishable biofilms can be quantitatively...

  8. Effect of immobilized cells in calcium alginate beads in alcoholic fermentation.

    Science.gov (United States)

    Duarte, Juliana C; Rodrigues, J Augusto R; Moran, Paulo J S; Valença, Gustavo P; Nunhez, José R

    2013-05-30

    Saccharomyces cerevisiae cells were immobilized in calcium alginate and chitosan-covered calcium alginate beads and studied in the fermentation of glucose and sucrose for ethanol production. The batch fermentations were carried out in an orbital shaker and assessed by monitoring the concentration of substrate and product with HPLC. Cell immobilization in calcium alginate beads and chitosan-covered calcium alginate beads allowed reuse of the beads in eight sequential fermentation cycles of 10 h each. The final concentration of ethanol using free cells was 40 g L-1 and the yields using glucose and sucrose as carbon sources were 78% and 74.3%, respectively. For immobilized cells in calcium alginate beads, the final ethanol concentration from glucose was 32.9 ± 1.7 g L-1 with a 64.5 ± 3.4% yield, while the final ethanol concentration from sucrose was 33.5 ± 4.6 g L-1 with a 64.5 ± 8.6% yield. For immobilized cells in chitosan-covered calcium alginate beads, the ethanol concentration from glucose was 30.7 ± 1.4 g L-1 with a 61.1 ± 2.8% yield, while the final ethanol concentration from sucrose was 31.8 ± 6.9 g L-1 with a 62.1 ± 12.8% yield. The immobilized cells allowed eight 10 h sequential reuse cycles to be carried out with stable final ethanol concentrations. In addition, there was no need to use antibiotics and no contamination was observed. After the eighth cycle, there was a significant rupture of the beads making them inappropriate for reuse.

  9. Cell sheets prepared via gel-sol transition of calcium RGD-alginate.

    Science.gov (United States)

    Yan, Jing; Chen, Fei; Amsden, Brian G

    2016-01-01

    The formation of layered tissues through the use of cell sheet harvesting has recently emerged as a potentially viable approach for clinical tissue engineering applications. Since the demonstration of effective cell sheet formation using temperature responsive substrates, a number of different stimuli have been utilized to facilitate cell sheet detachment. Each approach has differing advantages and disadvantages. Herein we demonstrate the ability of calcium alginate hydrogels to function as an effective substrate for cell sheet formation. By conjugating the integrin binding peptide sequence RGD to the alginate and crosslinking it with calcium ions, the hydrogel formed supported the attachment and growth of both 3T3 fibroblasts and human corneal epithelial cells (HCECs). Once the cells had grown to confluence, exposing the calcium alginate to the chelating agent citrate caused the release of a consolidated cell sheet. When HCEC sheets were stacked, the cell layers adhered to each other and the cells began to integrate. Herein we describe a simple and inexpensive process for creating cell sheets using the ability of calcium alginate hydrogels to be dissolved under mild conditions. The alginate was first modified to possess cell attachment sites and in this demonstration of feasibility we employed an RGD peptide, but other peptides could be readily attached. The modified alginate was then formed into stable hydrogels through a drying and re-hydration step, and used as a substrate to grow confluent cell sheets of human corneal epithelial cells and 3T3 fibroblasts as examples. The cell sheets were released through chelating the calcium using citrate. The cell-cell connections were retained following this release and the cell sheets interconnect and grew following being stacked. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. In Situ Gelation for Cell Immobilization and Culture in Alginate Foam Scaffolds

    Science.gov (United States)

    Markussen, Christine; Dornish, Michael; Heier-Baardson, Helene; Melvik, Jan Egil; Alsberg, Eben; Christensen, Bjørn E.

    2014-01-01

    Essential cellular functions are often lost under culture in traditional two-dimensional (2D) systems. Therefore, biologically more realistic three-dimensional (3D) cell culture systems are needed that provide mechanical and biochemical cues which may otherwise be unavailable in 2D. For the present study, an alginate-based hydrogel system was used in which cells in an alginate solution were seeded onto dried alginate foams. A uniform distribution of NIH:3T3 and NHIK 3025 cells entrapped within the foam was achieved by in situ gelation induced by calcium ions integrated in the foam. The seeding efficiency of the cells was about 100% for cells added in a seeding solution containing 0.1–1.0% alginate compared with 18% when seeded without alginate. The NHIK 3025 cells were allowed to proliferate and form multi-cellular structures inside the transparent gel that were later vital stained and evaluated by confocal microcopy. Gels were de-gelled at different time points to isolate the multi-cellular structures and to determine the spheroid growth rate. It was also demonstrated that the mechanical properties of the gel could largely be varied through selection of type and concentration of the applied alginate and by immersing the already gelled disks in solutions providing additional gel-forming ions. Cells can efficiently be incorporated into the gel, and single cells and multi-cellular structures that may be formed inside can be retrieved without influencing cell viability or contaminating the sample with enzymes. The data show that the current system may overcome some limitations of current 3D scaffolds such as cell retrieval and in situ cell staining and imaging. PMID:24125496

  11. The effect of host factors and capsule composition on the cellular overgrowth on implanted alginate capsules.

    Science.gov (United States)

    King, A; Sandler, S; Andersson, A

    2001-12-05

    Microencapsulation of islets of Langerhans in alginate/poly-L-lysine (PLL)/alginate capsules may provide a method for transplantation in the absence of immunosuppression. The aim of this study was to investigate the problem of overgrowth on implanted capsules with regard to the composition of the capsules and host factors such as cytokine and nitric oxide production. Empty capsules were implanted to C57BL/6 mice for 1, 3, 7, or 28 days. Glucose oxidation rates showed the metabolic activity of the cellular overgrowth on retrieved capsules. DNA content, histological score, and retrieval rates were also measured to assess the overgrowth. It was noted that the pericapsular host reaction arose by day 7 and had not increased further by day 28. Capsules of varying alginate compositions and different concentrations of PLL were implanted for 7 days to either C57BL/6 or Balb/c mice. Capsules were also implanted to mice lacking the inducible nitric oxide synthase enzyme. Glucose oxidation rates, DNA content, and histological score were positively correlated to each other and negatively correlated to retrieval rates. The pericapsular reaction was reduced if PLL was omitted from the capsule or if a high mannuronic acid alginate was used. Balb/c mice had reduced cellular overgrowth on implanted capsules and had reduced mRNA expression of interleukin-1 beta and tumor necrosis factor-alpha in their peritoneal macrophages. The capsular overgrowth seemed more severe in animals lacking inducible nitric oxide synthase compared with wild-type controls. It is concluded that alginate composition, PLL, and recipient factors such as nitric oxide production and cytokine expression affect the cellular overgrowth on implanted alginate capsules. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 374-383, 2001

  12. Optimization of alginate microcapsules containing cells overexpressing α-l-iduronidase using Box-Behnken design.

    Science.gov (United States)

    Diel, Dirnete; Lagranha, Valeska Lizzi; Schuh, Roselena Silvestri; Bruxel, Fernanda; Matte, Ursula; Teixeira, Helder Ferreira

    2018-01-01

    Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease caused by deficiency of α-l-iduronidase (IDUA), which results in the lysosomal accumulation of glycosaminoglycans (GAG) leading to widespread clinical manifestations. The microencapsulation of IDUA overexpressing recombinant cells has been considered as a promising strategy for the treatment of MPS I. This study aimed at the optimization of alginate microcapsules containing recombinant BHK (Baby Hamster Kidney) cells (rBHK) overexpressing IDUA produced by electrostatic extrusion technique. The alginate microcapsule (MC-A) optimization study was carried out by means of an experimental Box-Behnken Design that allowed the simultaneous evaluation of the influence of voltage (kV), alginate/cell suspension flow (mL/h), and alginate concentration (%) on size and IDUA activity. The optimal conditions of voltage (10kV), flow (25mL/h), and alginate concentration (1.3%) made possible to obtain the smallest microcapsules showing the highest IDUA activity. After optimization, the microcapsules were sequentially coated with PLL and alginate (MC-APA) to increase their stability. MC-A and MC-APA presented monodisperse populations (spanmicrocapsules containing rBHK cells in a MPS I murine model, a significant increase in IDUA activity was observed in the skin near the implant. Histological analysis revealed an inflammatory infiltrate at the application site, which did not prevent the release of the enzyme under the conditions evaluated. Taken together, the overall results demonstrate the feasibility of MC-APA as a potential alternative for local treatment of MPS I. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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 polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly-l-lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)-block-poly(l-lysine hydrochloride) (PEG454-b-PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454-b-PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP-1 monocytes was observed with both PLL and PEG454-b-PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties. PMID:23853069

  14. Improved seeding of chondrocytes into polyglycolic acid scaffolds using semi-static and alginate loading methods.

    Science.gov (United States)

    Shahin, Kifah; Doran, Pauline M

    2011-01-01

    Cell seeding and attachment in three-dimensional scaffolds is a key step in tissue engineering with implications for cell differentiation and tissue development. In this work, two new seeding methods were investigated using human chondrocytes and polyglycolic acid (PGA) fibrous mesh scaffolds. A simple semi-static seeding method using culture plates and tissue flasks was developed as an easy-to-perform modification of static seeding. An alginate-loading method was also studied, using alginate hydrogel as an adjuvant for entrapping cells within PGA scaffolds. Both the semi-static and PGA-alginate methods produced more homogeneous cell distributions than conventional static and dynamic seeding. Using 20 × 10(6) cells, whereas the seeding efficiency for static seeding was only 52%, all other techniques produced seeding efficiencies of ≥ 90%. With 40 × 10(6) cells, the efficiency of semi-static seeding declined to 74% while the dynamic and PGA-alginate methods retained their ability to accommodate high cell numbers. The seeded scaffolds were cultured in recirculation bioreactors to determine the effect of seeding method on cartilage production. Statically seeded scaffolds did not survive the 5-week cultivation period. Deposition of extracellular matrix in scaffolds seeded using the semi-static and PGA-alginate methods was more uniform compared with scaffolds seeded using the dynamic method. The new semi-static and PGA-alginate seeding methods developed in this work are recommended for tissue engineering because they provide substantial benefits compared with static seeding in terms of seeding efficiency, cell distribution, and cartilage deposition while remaining simple and easy to execute. Copyright © 2010 American Institute of Chemical Engineers (AIChE).

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

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Devendra, E-mail: devendra@rci.rutgers.edu; Desai, Malav S.; Kulkarni, Namrata; Langrana, Noshir

    2011-12-01

    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/m{sup 2} and - 0.32 mC/m{sup 2}, 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: {yields} Chitosan/alginate based fibrous polyelectrolyte complex films were developed. {yields} The average surface charge density of the films was determined using AFM. {yields} Elastic modulus of the films increased with increase in PEC content. {yields} FTIR analysis indicated higher alginate content on surface compared to bulk.

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

    Science.gov (United States)

    Hosseini, Seyed Mojtaba; Sharafkhah, Ali; Koohi-Hosseinabadi, Omid; Semsar-Kazerooni, Maryam

    2016-08-01

    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. The aim of this study was to discover whether NSCs cultured in alginate transplantation improve recovery from spinal cord injury. 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. 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. 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. 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 a rat model.

  17. Restoring proximal caries lesions conservatively with tunnel restorations

    Directory of Open Access Journals (Sweden)

    Chu CH

    2013-07-01

    Full Text Available Chun-Hung Chu1, May L Mei,1 Chloe Cheung,1 Romesh P Nalliah2 1Faculty of Dentistry, The University of Hong Kong, Hong Kong, People's Republic of China; 2Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA Abstract: The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations. Keywords: operative, practice, tunnel preparation, composite, amalgam, glass ionomer

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

    Directory of Open Access Journals (Sweden)

    Xiao-wei Zhao

    2008-03-01

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

  19. 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...... fish sarcoplasmic proteins (FSP), prepared by bulk mixing. A concentration screening revealed that there was a range of alginate and FSP concentrations where stable NCXs with similar properties were formed, rather than two exact concentrations. The size of the NCXs was 293 +/- 3 nm, and the zeta...

  20. Synthesis and Characterization of Chitosan- Alginate for Controlled Release of Isoniazid Drug

    Directory of Open Access Journals (Sweden)

    Sari Edi Cahyaningrum

    2015-03-01

    Full Text Available The aim of this research was to synthesize and characterize chitosan-calcium alginate as matrix isoniazid encapsulation to produce controlled release isoniazid drug. The microparticles were evaluated for surface morphology, functional groups, size particles, drug content and swelling index. The drug release kinetic was investigated at gastric and intestinal artificial pH. The results showed that isoniazid-calcium alginate-chitosan has majority particle diameter of 1001-1500 nm. The release mechanism of isoniazid was through combination of erosion and diffusion.

  1. Microwave based synthesis of polymethyl methacrylate grafted sodium alginate: its application as flocculant.

    Science.gov (United States)

    Rani, Priti; Mishra, Sumit; Sen, Gautam

    2013-01-16

    Polymethyl methacrylate grafted sodium alginate (SAG-g-PMMA) was synthesized by microwave assisted method. The grafting of the PMMA chains on the polysaccharide backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H, N, O and Na), SEM and TGA study. The intrinsic viscosity of sodium alginate appreciably improved on grafting of PMMA chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied in coal fine suspension through jar test procedure, toward possible application as flocculant. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. 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

    of solvent. Different interaction effect of three extraction factors of temperature (60–100 °C), alkali (1–5 %), and aqueous ethanol (70–100 %) were studied to reduce residual waste. The result showed that the optimum extraction yield (13.57 %) was obtained with 86 °C temperature, 3 % alkali, and 93...... extraction were evaluated for total polyphenols and its antioxidant capacity. The extracted alginate was further characterized using fluorescence spectrophotometer and nuclear magnetic resonance spectroscopy. The 1H NMR data revealed that extracted alginate has an M/G ratio of 1.08 and η 

  3. Effect of calcium chloride concentration on output force in electrical actuator made of sodium alginate gel

    Science.gov (United States)

    Wu, Yuda; Zhao, Gang; Wei, Chengye; Liu, Shuang; Fu, Yu; Liu, Xvxiong

    2018-01-01

    As a kind of artificial muscle intelligent material, the biological gel electric driver has the advantages of low driving voltage, large strain, good biological compatibility, good flexibility, low price, etc. The application prospect is broad and it has high academic value. Alginate, as a common substance in sea, has characteristics of low cost, green and pollution-free. Therefore,this paper obtains biological gel electric actuator by sodium alginate and calcium chloride. Effects on output force of the electric actuator is researched by changing the crosslinking of calcium chloride concentration and the output force enhancement mechanism is analyzed in this paper.

  4. Optimized spray drying process for preparation of one-step calcium-alginate gel microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Popeski-Dimovski, Riste [Department of physic, Faculty of Natural Sciences and Mathematics, “ss. Cyril and Methodius” University, Arhimedova 3, 1000 Skopje, R. Macedonia (Macedonia, The Former Yugoslav Republic of)

    2016-03-25

    Calcium-alginate micro particles have been used extensively in drug delivery systems. Therefore we establish a one-step method for preparation of internally gelated micro particles with spherical shape and narrow size distribution. We use four types of alginate with different G/M ratio and molar weight. The size of the particles is measured using light diffraction and scanning electron microscopy. Measurements showed that with this method, micro particles with size distribution around 4 micrometers can be prepared, and SEM imaging showed that those particles are spherical in shape.

  5. Skjern River Restoration Counterfactual

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    of Dissonance in Nature Restoration’, Journal of Landscape Architecture 2/2014: 58-67. Danish Nature Agency (2005), Skjern Å: Ådalens historie. De store projekter. Det nye landskab og naturen. På tur i ådalen [The Skjern River: The History of the River Delta. The Big Projects. The New Landscape and Nature......In 2003 the Skjern River Restoration Project in Denmark was awarded the prestigious Europa Nostra Prize for ‘conserving the European cultural heritage’ (Danish Nature Agency 2005). In this case, however, it seems that the conservation of one cultural heritage came at the expense of another cultural...... history and more openness towards constant change. In this approach the idea of palimpsest as metaphor for the cultural landscape plays an important role. Rather than being an obstacle for the restoration of nature, the historical layer following the comprehensive cultivation project from the 1960s...

  6. A Hoseus Banjo Restoration

    OpenAIRE

    Politzer, David

    2016-01-01

    Intrigued by the sound of another recently restored example, I attempted to bring a sadly abused, bottom-of-the-line, Hoseus-equipped banjo up to playable condition. Reminders, lessons learned, and the joy of (albeit crude) handiwork made it well- worth the purchase price. The actual sound and physics of the Hoseus contraption remain hidden in the complex interaction of the various parts, as demonstrated by the accompanying sound samples.

  7. Relativistic Linear Restoring Force

    Science.gov (United States)

    Clark, D.; Franklin, J.; Mann, N.

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

  8. Setting standards of restorative justice

    Directory of Open Access Journals (Sweden)

    Kostić Miomira

    2007-01-01

    Full Text Available In the article the author deals with the basic theoretical statements and discussions about the practical use of restorative justice. She discusses the questions of introducing and application of restorative justice in order to reach the balance of interests between a victim, society and a delinquent. There is no unique statement about the restorative justice concept, so the authors make this concept by listing certain activities with rispect of standards and principles. Also she emphasizes the values of restorative justice process. A part of the article is dedicated to the standards for restorative justice that are harmonized with the international documents of human rights. .

  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

    2017-02-01

    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. Copyright © 2014 John Wiley & Sons, Ltd.

  11. 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.

  12. A comparative study for lipase immobilization onto alginate based composite electrospun nanofibers with effective and enhanced stability.

    Science.gov (United States)

    İspirli Doğaç, Yasemin; Deveci, İlyas; Mercimek, Bedrettin; Teke, Mustafa

    2017-03-01

    In this study, lipase was successfully immobilized on polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers that were prepared by electrospinning. Results showed that nanofibers (especially polyvinyl alcohol/alginate) enhanced the stability properties of lipase. When the free lipase lost its all activity after 40-60min at high temperatures, both lipase immobilized nanofibers kept almost 65-70% activity at the same time. The lipase immobilized poly vinyl alcohol/alginate and polyethylene oxide/alginate nanofibers protected approximately all of their activities until pH 9. Lipase immobilized polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers maintained 60% of their activities after 14 and 7 reuses, respectively. The morphology of nanofibers was characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Thermal Gravimetric Analyzer. As a result, this nanofiber production method, electrospinning, is simple, versatile and economical for preparing appropriate carrier to immobilize the enzymes. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2014-01-01

    Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedure and cell concentration do not affect the diameter of alginate beads, ii) encapsulation of high cell numbers (up to 10×106 cells/ml) can be performed in alginate beads utilizing high voltage and iii) high voltage (15–30 kV) does not alter the viability, proliferation and differentiation capacity of MSCs post-encapsulation compared with alginate encapsulated cells produced by the traditional air-flow method. The consistent results were obtained over the period of 7 days of encapsulated MSCs culture and after cryopreservation utilizing a slow cooling procedure (1 K/min). The results of this work show that high voltage encapsulation can further be maximized to develop cell-based therapies with alginate beads in a non-human primate model towards human application. PMID:25259731

  14. Effect of alginate and chitosan on viability and release behavior of Bifidobacterium pseudocatenulatum G4 in simulated gastrointestinal fluid.

    Science.gov (United States)

    Kamalian, Nikoo; Mirhosseini, Hamed; Mustafa, Shuhaimi; Manap, Mohd Yazid Abd

    2014-10-13

    The main aim of this study was to investigate the effect of different coating materials (i.e. Na-alginate and chitosan) on the viability and release behavior of Bifidobacterium pseudocatenulatum G4 in the simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). This study reports the viability of encapsulated B. pseudocatenulatum G4 coated using different alginate (2-4 g/100mL) and chitosan (0.2-0.8 g/100mL) concentrations. The results indicated that the highest concentration of alginate (4.4142 g/100mL) along with 0.5578 g/100mL chitosan resulted in the highest viability of B. pseudocatenulatum G4. The release behavior of the encapsulated probiotics in SGF (pH 1.5) in 2h followed by 4h in SIF (pH 7.4) was also assessed. The resistance rate of alginate-chitosan capsule in SGF was higher than SIF. The alginate-chitosan encapsulated cells had also more resistance than alginate capsules. The current study revealed that alginate encapsulated B. Pseudocatenulatum G4 exhibited longer survival than its free cells (control). Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Insulin-loaded nanoparticles are prepared by alginate ionotropic pre-gelation followed by chitosan polyelectrolyte complexation.

    Science.gov (United States)

    Sarmento, B; Ribeiro, A J; Veiga, F; Ferreira, D C; Neufeld, R J

    2007-08-01

    Alginate nanoparticles were prepared from dilute alginate sol by inducing a pre-gel with calcium counter ions, followed by polyelectrolyte complex coating with chitosan. Particles in the nanometer size range were obtained with 0.05% alginate and 0.9 mM Ca2+. The mean particle size was influenced by time and stirring speed of nanoparticle preparation, by alginate guluronic acid content and chitosan molecular weight and by the initial alginate:chitosan mass ratio. The association efficiency of insulin into alginate nanoparticles, as well as loading capacity were mainly influenced by the alginate:chitosan mass ratio. Under optimized size conditions, the association efficiency and loading capacities were as high as 92% and 14.3%, respectively. Approximately 50% of the protein was partially retained by the nanoparticles in gastric pH environment up to 24 hours while a more extensive release close to 75% was observed under intestinal pH conditions. Mild formulation conditions, optimum particle size range obtained, high insulin entrapment efficiency, and resistance to gastrointestinal release seem to be synergic and promising factors toward development of an oral insulin delivery form.

  17. Investigating metal removal potential by Effective Microorganisms (EM) in alginate-immobilized and free-cell forms.

    Science.gov (United States)

    Ting, Adeline Su Yien; Rahman, Nurul Hidayah Abdul; Isa, Mohamed Ikmal Hafiz Mahamad; Tan, Wei Shang

    2013-11-01

    Metal removal potential of both alginate-immobilized and free-cells of Effective Microorganisms (EM-1™ Inoculant) was investigated in this study. Results revealed that removal of Cr(III), Cu(II) and Pb(II) followed a similar trend where alginate-immobilized EM were more efficient compared to free-cells of EM. For these metals, 0.940, 2.695 and 4.011 mg g(-1) of Cr(III), Cu(II) and Pb(II) were removed compared to only 0.160, 0.859 and 0.755 mg ml(-1) removed by free-cells, respectively. The higher efficiency of alginate-immobilized EM was primarily attributed to the alginate matrix. This was evident when both alginate-immobilized EM and plain alginate beads (without EM), were not significantly different in their removal efficacies. Presence of alginate also enhanced the use of the biosorbents as maximum metal sorption was achieved after 120 min as opposed to only 60 min for free-cells. EM per se in immobilized or free-cell forms did not enhance metal removal efficacy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. 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

  19. Alginate inhibits iron absorption from ferrous gluconate in a randomized controlled trial and reduces iron uptake into Caco-2 cells.

    Directory of Open Access Journals (Sweden)

    Anna A Wawer

    Full Text Available Previous in vitro results indicated that alginate beads might be a useful vehicle for food iron fortification. A human study was undertaken to test the hypothesis that alginate enhances iron absorption. A randomised, single blinded, cross-over trial was carried out in which iron absorption was measured from serum iron appearance after a test meal. Overnight-fasted volunteers (n = 15 were given a test meal of 200 g cola-flavoured jelly plus 21 mg iron as ferrous gluconate, either in alginate beads mixed into the jelly or in a capsule. Iron absorption was lower from the alginate beads than from ferrous gluconate (8.5% and 12.6% respectively, p = 0.003. Sub-group B (n = 9 consumed the test meals together with 600 mg calcium to determine whether alginate modified the inhibitory effect of calcium. Calcium reduced iron absorption from ferrous gluconate by 51%, from 11.5% to 5.6% (p = 0.014, and from alginate beads by 37%, from 8.3% to 5.2% (p = 0.009. In vitro studies using Caco-2 cells were designed to explore the reasons for the difference between the previous in vitro findings and the human study; confirmed the inhibitory effect of alginate. Beads similar to those used in the human study were subjected to simulated gastrointestinal digestion, with and without cola jelly, and the digestate applied to Caco-2 cells. Both alginate and cola jelly significantly reduced iron uptake into the cells, by 34% (p = 0.009 and 35% (p = 0.003 respectively. The combination of cola jelly and calcium produced a very low ferritin response, 16.5% (p < 0.001 of that observed with ferrous gluconate alone. The results of these studies demonstrate that alginate beads are not a useful delivery system for soluble salts of iron for the purpose of food fortification.ClinicalTrials.gov NCT01528644.

  20. Preparation and characterization of alginate and psyllium beads containing Lactobacillus acidophilus.

    Science.gov (United States)

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59 ± 0.04 to 1.67 ± 0.09 mm for ALG and from 1.61 ± 0.06 to 1.80 ± 0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating.