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Sample records for alginate beads generated

  1. A Controlled Drug-Delivery Experiment Using Alginate Beads

    ERIC Educational Resources Information Center

    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.…

  2. Viscoelastic properties of mineralized alginate hydrogel beads.

    PubMed

    Olderøy, Magnus O; Xie, Minli; Andreassen, Jens-Petter; Strand, Berit L; Zhang, Zhibing; Sikorski, Pawel

    2012-07-01

    Alginate hydrogels have applications in biomedicine, ranging from delivery of cells and growth factors to wound management aids. However, they are mechanically soft and have shown little potential for the use in bone tissue engineering. Here, the viscoelastic properties of alginate hydrogel beads mineralized with calcium phosphate, both by a counter-diffusion (CD) and an enzymatic approach, are characterized by a micro-manipulation technique and mathematical modeling. Fabricated hydrogel materials have low mineral content (below 3 % of the total hydrogel mass, which corresponds to mineral content of up to 60 % of the dry mass) and low dry mass content (<5 %). For all samples compression and hold (relaxation after compression) data was collected and analyzed. The apparent Young's modulus of the mineralized beads was estimated by the Hertz model (compression data) and was shown to increase up to threefold upon mineralization. The enzymatically mineralized beads showed higher apparent Young's modulus compared to the ones mineralized by CD, even though the mineral content of the former was lower. Full compression-relaxation force-time profiles were analyzed using viscoelastic model. From this analysis, infinite and instantaneous Young's moduli were determined. Similarly, enzymatic mineralized beads, showed higher instantaneous and infinite Young's modulus, even if the degree of mineralization is lower then that achieved for CD method. This leads to the conclusion that both the degree of mineralization and the spatial distribution of mineral are important for the mechanical performance of the composite beads, which is in analogy to highly structured mineralized tissues found in many organisms.

  3. Optimization of alpha-amylase immobilization in calcium alginate beads.

    PubMed

    Ertan, Figen; Yagar, Hulya; Balkan, Bilal

    2007-01-01

    alpha-Amylase enzyme was produced by Aspergillus sclerotiorum under SSF conditions, and immobilized in calcium alginate beads. Effects of immobilization conditions, such as alginate concentration, CaCl(2) concentration, amount of loading enzyme, bead size, and amount of beads, on enzymatic activity were investigated. Optimum alginate and CaCl(2) concentration were found to be 3% (w/v). Using a loading enzyme concentration of 140 U mL(-1), and bead (diameter 3 mm) amount of 0.5 g, maximum enzyme activity was observed. Beads prepared at optimum immobilization conditions were suitable for up to 7 repeated uses, losing only 35% of their initial activity. Among the various starches tested, the highest enzyme activity (96.2%) was determined in soluble potato starch hydrolysis for 120 min at 40 degrees C.

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

    PubMed

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

    2007-01-01

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

  5. Characterization of an encapsulation device for the production of monodisperse alginate beads for cell immobilization.

    PubMed

    Serp, D; Cantana, E; Heinzen, C; Von Stockar, U; Marison, I W

    2000-10-01

    An encapsulation device, designed on the basis of the laminar jet break-up technique, is characterized for cell immobilization with different types of alginate. The principle of operation of the completely sterilizable encapsulator, together with techniques for the continuous production of beads from 250 microm to 1 mm in diameter, with a size distribution below 5%, at a flow rate of 1-15 mL/min, is described. A modification of the device, to incorporate an electrostatic potential between the alginate droplets and an internal electrode, results in enhanced monodispersity with no adverse effects on cell viability. The maximum cell loading capacity of the beads strongly depends on the nozzle diameter as well as the cells used. For the yeast Phaffia rhodozyma, it is possible to generate 700 microm alginate beads with an initial cell concentration of 1 x 10(8) cells/mL of alginate whereas only 1 x 10(6) cells/ml could be entrapped within 400 microm beads. The alginate beads have been characterized with respect to mechanical resistance and size distribution immediately after production and as a function of storage conditions. The beads remain stable in the presence of acetic acid, hydrochloric acid, water, basic water, and sodium ions. The latter stability applies when the ratio of sodium: calcium ions is less than 1/5. Complexing agents such as sodium citrate result in the rapid solubilization of the beads due to calcium removal. The presence of cells does not affect the mechanical resistance of the beads. Finally, the mechanical resistance of alginate beads can be doubled by treatment with 5-10 kDa chitosan, resulting in reduced leaching of cells.

  6. Fabrication of novel core-shell hybrid alginate hydrogel beads.

    PubMed

    Liu, Hongxia; Wang, Chaoyang; Gao, Quanxing; Liu, Xinxing; Tong, Zhen

    2008-03-01

    Novel hybrid alginate hydrogel beads with shells of porous CaCO3 microparticles were fabricated by templating water-in-oil emulsion and subsequent in situ gelation. Porous CaCO3 microparticles were self-assembled at interfaces of water-in-oil emulsion. Water droplets containing alginate in the emulsion were subsequently in situ gelated by Ca2+ released from CaCO3 through decreasing pH with slow hydrolysis of d-glucono-delta-lactone (GDL). The resulting hybrid beads with alginate gel cores and shells of porous CaCO3 microparticles were called colloidosomes. The packed density of CaCO3 microparticles in the shell increased with increasing the ratio of the CaCO3 microparticle weight to the water phase volume Mp/Vw and decreased with addition of NaCl into water. The size of the produced colloidosome beads was independent of Mp/Vw. Increasing the volume fraction of water Phi w to 0.5, some colloidosome beads deformed to nonspheral shape and even broken. Brilliant blue (BB) as a drug model was loaded into the colloidosome beads by being dissolved in the alginate aqueous solution before gelation. The BB release from the colloidosome beads was slowed down because of the formation of the shells of CaCO3 microparticles. The colloidosome beads may find applications as delivery vehicles for drugs, cosmetics, food supplements and living cell.

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

    PubMed

    Edwards-Lévy, F; Lévy, M C

    1999-11-01

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

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

    PubMed Central

    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

  9. Fabrication of cross-linked alginate beads using electrospraying for adenovirus delivery.

    PubMed

    Park, Hongkwan; Kim, Pyung-Hwan; Hwang, Taewon; Kwon, Oh-Joon; Park, Tae-Joon; Choi, Sung-Wook; Yun, Chae-Ok; Kim, Jung Hyun

    2012-05-10

    Cross-linked alginate beads containing adenovirus (Ad) were successfully fabricated using an electrospraying method to achieve the protection and release of Ad in a controlled manner. An aqueous alginate solution containing Ad was electrosprayed into an aqueous phase containing a cross-linking agent (calcium chloride) at different process variables (voltages, alginate concentrations, and flow rates). Alginate beads containing Ad were used for transduction of U343 glioma cells and the transduction efficiency of the alginate beads was measured by quantification of gene expression using a fluorescence-activated cell sorter at different time points. In vitro results of gene expression revealed that the Ad encapsulated in the alginate beads with 0.5 wt% of alginate concentration exhibited a high activity for a long period (over 7 days) and was released in a sustained manner from the alginate beads. The Ad-encapsulating alginate beads could be promising materials for local delivery of Ad at a high concentration into target sites.

  10. Bioglass/alginate composite hydrogel beads as cell carriers for bone regeneration.

    PubMed

    Zeng, Qiongyu; Han, Yan; Li, Haiyan; Chang, Jiang

    2014-01-01

    Cell carrier is a useful biomedical tool to deliver particular kind of cells to a specific site for cell therapy or tissue regeneration. In the current study, 45S5 bioglass (BG) was introduced into alginate (ALG) to generate BG/ALG composite hydrogel beads as cell carriers. The ions releasing behavior, dimensional stability and in vitro bioactivity of the beads were investigated. Results showed that the BG/ALG beads revealed similar calcium ion releasing behavior as compared with ALG beads. In addition, silicon ion releasing was detected in BG/ALG beads. BG/ALG and ALG beads shared similar dimensional stability, and BG/ALG beads could induce apatite deposition on their surface after being soaked in stimulated body fluid. Then, the effects of ion extracts from hydrogel beads on cell behavior were investigated. Results confirmed that extracts of BG/ALG beads could simulate proliferation and osteogenic differentiation of mesenchymal stem cells as well as angiogenesis of endothelial cells. Furthermore, MC3T3-E1 cells were successfully encapsulated in hydrogel beads. BG/ALG beads enhanced the cell proliferation and stimulated osteogenic differentiation of the encapsulated MC3T3-E1 cells as compared with ALG beads. Therefore, BG/ALG composite hydrogel beads loaded with bone forming cells may be useful tools for bone regeneration and tissue engineering applications.

  11. As(III) and As(V) removal from the aqueous phase via adsorption onto acid mine drainage sludge (AMDS) alginate beads and goethite alginate beads.

    PubMed

    Lee, Hongkyun; Kim, Dohyeong; Kim, Jongsik; Ji, Min-Kyu; Han, Young-Soo; Park, Young-Tae; Yun, Hyun-Shik; Choi, Jaeyoung

    2015-07-15

    Acid mine drainage sludge (AMDS) is a solid waste generated following the neutralization of acid mine drainage (AMD). This material entrapped in calcium alginate was investigated for the sorption of As(III) and As(V). Three different adsorbent materials were prepared: AMDS alginate beads (AABs), goethite alginate beads (GABs), and pure alginate beads. The effects of pH and the adsorption kinetics were investigated, and the adsorption isotherms were also evaluated. The optimum pH range using the AABs was determined to be within 2-10 for As(III) and 2-9 for As(V). Adsorption equilibrium data were evaluated using the Langmuir isotherm model, and the maximum adsorption capacity qmax was 18.25 and 4.97 mg g(-1) for As(III) on AAB and GAB, respectively, and 21.79 and 10.92 mg g(-1) for As(V) on AAB and GAB, respectively. The adsorption of As(III) and As(V) was observed to follow pseudo-second order kinetics. The As K-edge X-ray absorption near-edge structure (XANES) revealed that the adsorbed As(III) on the AABs was oxidized to As(V) via manganese oxide in the AMDS. PMID:25804789

  12. As(III) and As(V) removal from the aqueous phase via adsorption onto acid mine drainage sludge (AMDS) alginate beads and goethite alginate beads.

    PubMed

    Lee, Hongkyun; Kim, Dohyeong; Kim, Jongsik; Ji, Min-Kyu; Han, Young-Soo; Park, Young-Tae; Yun, Hyun-Shik; Choi, Jaeyoung

    2015-07-15

    Acid mine drainage sludge (AMDS) is a solid waste generated following the neutralization of acid mine drainage (AMD). This material entrapped in calcium alginate was investigated for the sorption of As(III) and As(V). Three different adsorbent materials were prepared: AMDS alginate beads (AABs), goethite alginate beads (GABs), and pure alginate beads. The effects of pH and the adsorption kinetics were investigated, and the adsorption isotherms were also evaluated. The optimum pH range using the AABs was determined to be within 2-10 for As(III) and 2-9 for As(V). Adsorption equilibrium data were evaluated using the Langmuir isotherm model, and the maximum adsorption capacity qmax was 18.25 and 4.97 mg g(-1) for As(III) on AAB and GAB, respectively, and 21.79 and 10.92 mg g(-1) for As(V) on AAB and GAB, respectively. The adsorption of As(III) and As(V) was observed to follow pseudo-second order kinetics. The As K-edge X-ray absorption near-edge structure (XANES) revealed that the adsorbed As(III) on the AABs was oxidized to As(V) via manganese oxide in the AMDS.

  13. Controlled microfluidic production of alginate beads for in situ encapsulation of microbes

    SciTech Connect

    Kalyanaraman, Meenaa; Retterer, Scott T; McKnight, Timothy E; Ericson, Milton Nance; Allman, Steve L; Elkins, James G; Palumbo, Anthony Vito; Keller, Martin; Doktycz, Mitchel John

    2009-01-01

    The development and refinement of a microfluidic-based alginate bead generator system for bacterial encapsulation is presented. The resulting microgels have application for the encapsulation of single cells, and can allow for small scale, clonal expansion of thousands of isolated cells in parallel. PDMS based microfluidic chips were fabricated using conventional lithography techniques to produce both externally gelled and directly gelled alginate microspheres using a controlled, water-in-oil emulsion system. The production of directly gelled beads, formed by the in-chip mixing of aqueous alginate and calcium chloride solutions dispersed within an organic carrier flowstream is qualitatively compared to a system, which produces beads and relies on diffusion of a crosslinking agent from the carrier fluid to cause gelation (external gelation). While the direct gelation scheme allows the use of biocompatible oils as the organic carrier, it also has a detrimental effect on device stability often resulting in clogging and gel-streaming at the microfluidic interface of these solutions. A design for the continuous production of directly gelled beads was evaluated in terms of the threshold flow conditions and reagent concentrations that did not result in clogging or streaming. Monodisperse alginate microgels of 30 mum diameter were produced at frequencies of over 500 beads per second. The beads could be completely dispersed into aqueous media using an off-chip washing protocol to remove the organic phase. The microgels effectively encapsulated individual or small numbers of GFP-expressing Escherichia. coli, which could be subsequently clonally expanded. The described microfluidic platform is a robust front-end sample preparation technology that shows strong potential for use in drug delivery systems, biosensors, and other cell-based microcompartmentalization applications. The co-culturing of microbial colonies in a large population of alginate beads will allow for functional

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

    PubMed

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

    2013-01-30

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

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

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

    2016-09-01

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

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

    PubMed

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

    2016-09-01

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

  19. Purification of alpha-amylases using magnetic alginate beads.

    PubMed

    Teotia, S; Gupta, M N

    2001-03-01

    Magnetic alginate beads were used to purify alpha-amylases from porcine pancreas, starchzyme, BAN 240L (a commercial purification from Bacillus subtilis), and wheat germ. The beads bound a significant level of alpha-amylase activity from porcine pancreas, BAN 240L, and wheat germ. In each case, the enzyme activity could be eluted by using 1.0 M maltose, a known competitive inhibitor of alpha-amylase. In the case of BAN 240L, 3.6-fold purification with 72% recovery of activity was observed. In the case of wheat germ enzyme, starting from the crude extract, 48-fold purification with 70% activity recovery was observed. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis also indicated considerable purification in the latter case.

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

    PubMed

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

    2012-04-30

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

  1. Preparation of calcium alginate microgel beads in an electrodispersion reactor using an internal source of calcium carbonate nanoparticles.

    PubMed

    Zhao, Yinyan; Carvajal, M Teresa; Won, You-Yeon; Harris, Michael T

    2007-12-01

    An electrodispersion reactor has been used to prepare calcium alginate (Ca-alginate) microgel beads in this study. In the electrodispersion reactor, pulsed electric fields are utilized to atomize aqueous mixtures of sodium alginate and CaCO3 nanoparticles (dispersed phase) from a nozzle into an immiscible, insulating second liquid (continuous phase) containing a soluble organic acid. This technique combines the features of the electrohydrodynamic force driven emulsion processes and externally triggered gelations in microreactors (the droplets) ultimately to yield soft gel beads. The average particle size of the Ca-alginate gels generated by this method changed from 412 +/- 90 to 10 +/- 3 microm as the applied peak voltage was increased. A diagram depicting structural information for the Ca-alginate was constructed as a function of the concentrations of sodium alginate and CaCO3 nanoparticles. From this diagram, a critical concentration of sodium alginate required for sol-gel transformation was observed. The characteristic highly porous structure of Ca-alginate particles made by this technique appears suitable for microencapsulation applications. Finally, time scale analysis was performed for the electrodispersion processes that include reactions in the microreactor droplets to provide guidelines for the future employment of this technique. This electrodispersion reactor can be used potentially in the formation of many reaction-based microencapsulation systems.

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

    PubMed

    Bonine, Bárbara M; Polizelli, Patricia Peres; Bonilla-Rodriguez, Gustavo O

    2014-01-01

    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.

  3. Heavy metal sorption by calcium alginate beads from Laminaria digitata.

    PubMed

    Papageorgiou, Sergios K; Katsaros, Fotios K; Kouvelos, Evangelos P; Nolan, John W; Le Deit, Herve; Kanellopoulos, Nick K

    2006-10-11

    Alginate with a high M/G ratio, extracted from Laminaria digitata, was evaluated for Cu(2+), Cd(2+) and Pb(2+) sorption in acidic solutions, in the form of calcium cross-linked beads. The high M/G ratio of alginate extracted from this algal species is most likely the determining factor for the increased adsorption capacity of the investigated metals, indicating that the mannuronic acid is responsible for the ion exchange mechanism. The data obtained from the batch experiments have been interpreted with Langmuir, Freundlich and Sips models. The Sips equation provided the best fit with the experimental results, indicating sorption sites heterogeneity for the material. The pH was found to have a significant effect on the process, with sorption capacity reaching a maximum at pH 4.5, indicating a competition mechanism between H(+) and metal ions. Kinetic experiments were performed at the optimum pH. For the interpretation of the kinetic experiments the Linear Adsorption Model was employed and diffusion coefficients were determined. The model fits the experimental data at higher concentrations, where the adsorbed quantity remains almost constant. Finally, a simplified expression of the batch kinetic adsorption model was employed. The model, predicts adequately, not only the diffusivity values, but also the concentration profiles inside the spherical particles.

  4. Modulation of drug release from glyceryl palmitostearate-alginate beads via heat treatment.

    PubMed

    Pongjanyakul, Thaned; Sungthongjeen, Srisagul; Puttipipatkhachorn, Satit

    2006-08-17

    Diclofenac calcium alginate (DCA) beads containing glyceryl palmitostearate (GPS) were prepared by ionotropic gelation method. The effect of GPS amount and heat treatment on characteristics of the DCA beads was investigated. Incorporation of GPS into the DCA beads increased particle size and entrapment efficiency of diclofenac sodium (DS), but decreased water uptake in distilled water, and DS release rate. The heat treatment caused the DCA beads to be irregular shape particles and to possess higher water uptake. A slower release rate of DS in distilled water was found because of interaction of DS and alginate polymer matrix, and a restriction of water sorption into the inside region of the beads, which caused by the shrinkage of the beads after heating. However, the heat treatment did not affect particle shape and water uptake in distilled water of the 3%GPS-DCA beads. Differential scanning calorimetric study showed that GPS in the DCA beads was resolidified to different polymorph after cooling. Furthermore, the micro-Raman spectra indicated the existence of DS in the GPS matrix particles in the beads due to the partition of DS into the melted GPS during heat treatment. This led to a decrease in release rate of DS in pH 6.8 phosphate buffer and a change in DS release pattern in distilled water. Thus, not only the calcium alginate matrix, but also the resolidified GPS matrix in the alginate beads controlled the DS release from the 3%GPS-DCA beads with heat treatment.

  5. Preparation and evaluation of sustained release calcium alginate beads and matrix tablets of acetazolamide.

    PubMed

    Barzegar-Jalali, M; Hanaee, J; Omidi, Y; Ghanbarzadeh, S; Ziaee, S; Bairami-Atashgah, R; Adibkia, K

    2013-02-01

    The aim of this study was to develop sustained release dosage forms of acetazolamide (ACZ) preparing its calcium alginate beads and matrix tablets. ACZ was incorporated into calcium alginate beads using microencapsulation method. Two methods were applied to prolong ACZ release rate. In the first method, the drug was incorporated into calcium alginate beads either alone or with various polymers in internal phase. The second method involved the preparation of matrix tablet from the beads benefiting direct compression method with or without various polymers in external phase. The release rate of these prepared formulations and an innovator's sustained-release capsule (Diamox®) were assessed. In-vitro dissolution studies revealed that the matrix tablets prepared by the second method containing NaCMC could sustain ACZ release properly and the drug released until 9 h. It was also found that several parameters such as concentration of sodium alginate, calcium chloride and ACZ; type and concentration of polymers; syringe needle size as well as distance between needle tip and surface of the calcium chloride could affect the properties of beads, matrix tablets and subsequently release profile. Preparation of polymer free beads, incorporation of polymers in internal phase of the beads and direct compression of the beads did not give sustained release property. Whereas, incorporation of NaCMC in the external phase of the beads in matrix tablets or in combination with alginate powder in directly compressed conventional tablets could produce dosage form with sustained release property similar to reference formulation. PMID:23447074

  6. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    PubMed Central

    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 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. PMID:22645438

  7. Preparation and cytotoxicity of N,N,N-trimethyl chitosan/alginate beads containing gold nanoparticles.

    PubMed

    Martins, Alessandro F; Facchi, Suelen P; Monteiro, Johny P; Nocchi, Samara R; Silva, Cleiser T P; Nakamura, Celso V; Girotto, Emerson M; Rubira, Adley F; Muniz, Edvani C

    2015-01-01

    Polyelectrolyte complex beads based on N,N,N-trimethyl chitosan (TMC) and sodium alginate (ALG) were obtained. This biomaterial was characterised by FTIR, TGA/DTG, DSC and SEM analysis. The good properties of polyelectrolyte complex hydrogel beads were associated, for the first time, with gold nanoparticles (AuNPs). Through a straightforward methodology, AuNPs were encapsulated into the beads. The in vitro cytotoxicity assays on the Caco-2 colon cancer cells and healthy VERO cells showed that the beads presented good biocompatibility on both cell lines, whereas the beads loaded with gold nanoparticles (beads/AuNPs) was slightly cytotoxic on the Caco-2 and VERO cells.

  8. Okra (Hibiscus esculentus) gum-alginate blend mucoadhesive beads for controlled glibenclamide release.

    PubMed

    Sinha, Priyanka; Ubaidulla, U; Nayak, Amit Kumar

    2015-01-01

    The utility of isolated okra (Hibiscus esculentus) gum (OG) was evaluated as a potential sustained drug release polymer-blends with sodium alginate in the development of controlled glibenclamide release ionically-gelled beads for oral use. OG was isolated from okra fruits and its solubility, pH, viscosity and moisture content were studied. Glibenclamide-loaded OG-alginate blend beads were prepared using CaCl2 as cross-linking agent through ionic-gelation technique. These ionically gelled beads showed drug entrapment efficiency of 64.19 ± 2.02 to 91.86 ± 3.24%. The bead sizes were within 1.12 ± 0.11 to 1.28 ± 0.15 mm. These glibenclamide-loaded OG-alginate blend beads exhibited sustained in vitro drug release over a prolonged period of 8 h. The in vitro drug release from these OG-alginate beads were followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads was influenced by the pH of the test medium. These beads also exhibited good mucoadhesivity with goat intestinal mucosa.

  9. Okra (Hibiscus esculentus) gum-alginate blend mucoadhesive beads for controlled glibenclamide release.

    PubMed

    Sinha, Priyanka; Ubaidulla, U; Nayak, Amit Kumar

    2015-01-01

    The utility of isolated okra (Hibiscus esculentus) gum (OG) was evaluated as a potential sustained drug release polymer-blends with sodium alginate in the development of controlled glibenclamide release ionically-gelled beads for oral use. OG was isolated from okra fruits and its solubility, pH, viscosity and moisture content were studied. Glibenclamide-loaded OG-alginate blend beads were prepared using CaCl2 as cross-linking agent through ionic-gelation technique. These ionically gelled beads showed drug entrapment efficiency of 64.19 ± 2.02 to 91.86 ± 3.24%. The bead sizes were within 1.12 ± 0.11 to 1.28 ± 0.15 mm. These glibenclamide-loaded OG-alginate blend beads exhibited sustained in vitro drug release over a prolonged period of 8 h. The in vitro drug release from these OG-alginate beads were followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads was influenced by the pH of the test medium. These beads also exhibited good mucoadhesivity with goat intestinal mucosa. PMID:25312603

  10. Alginate beads of Captopril using galactomannan containing Senna tora gum, guar gum and locust bean gum.

    PubMed

    Pawar, Harshal A; Lalitha, K G; Ruckmani, K

    2015-05-01

    Gastro-retentive Captopril loaded alginate beads were prepared by an ionotropic gelation method using sodium alginate in combination with natural gums containing galactomannans (Senna tora seed gum, guar gum and locust bean gum) in the presence of calcium chloride. The process variables such as concentration of sodium alginate/natural polymer, concentration of calcium chloride, curing time, stirring speed and drying condition were optimized. Prepared beads were evaluated for various parameters such as flow property, drug content and entrapment efficiency, size and shape, and swelling index. Surface morphology of the beads was studied using scanning electron microscopy. In vitro mucoadhesion and in vitro drug release studies were carried out on the prepared beads. From the entrapment efficiency and dissolution study, it was concluded that galactomannans in combination with sodium alginate show sustained release property. The bead formulation F4 prepared using combination of sodium alginate and guar gums in the ratio 2:1 showed satisfactory sustained release for 12h. The release of Captopril from the prepared beads was found to be controlled by the swelling of the polymer followed by drug diffusion through the swelled polymer and slow erosion of the beads.

  11. Alginate beads of Captopril using galactomannan containing Senna tora gum, guar gum and locust bean gum.

    PubMed

    Pawar, Harshal A; Lalitha, K G; Ruckmani, K

    2015-05-01

    Gastro-retentive Captopril loaded alginate beads were prepared by an ionotropic gelation method using sodium alginate in combination with natural gums containing galactomannans (Senna tora seed gum, guar gum and locust bean gum) in the presence of calcium chloride. The process variables such as concentration of sodium alginate/natural polymer, concentration of calcium chloride, curing time, stirring speed and drying condition were optimized. Prepared beads were evaluated for various parameters such as flow property, drug content and entrapment efficiency, size and shape, and swelling index. Surface morphology of the beads was studied using scanning electron microscopy. In vitro mucoadhesion and in vitro drug release studies were carried out on the prepared beads. From the entrapment efficiency and dissolution study, it was concluded that galactomannans in combination with sodium alginate show sustained release property. The bead formulation F4 prepared using combination of sodium alginate and guar gums in the ratio 2:1 showed satisfactory sustained release for 12h. The release of Captopril from the prepared beads was found to be controlled by the swelling of the polymer followed by drug diffusion through the swelled polymer and slow erosion of the beads. PMID:25720832

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

    PubMed Central

    Bonine, Bárbara M.; Polizelli, Patricia Peres; Bonilla-Rodriguez, Gustavo O.

    2014-01-01

    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. PMID:24818012

  13. The release rate of curcumin from calcium alginate beads regulated by food emulsifiers.

    PubMed

    Song, Shili; Wang, Zhen; Qian, Yuhua; Zhang, Lijie; Luo, Erfeng

    2012-05-01

    Curcumin-loaded alginate beads, which contain different food emulsifiers, have been prepared using CaCl₂ as the cross-linking agent. The controlled release of the curcumin from the beads was investigated at room temperature. For calcium alginate/Span-80/Tween-80 (A/S/T) formulations, almost all of the curcumin loaded in the beads was released into the medium within about 20 h, and the release rates could be regulated by changing the concentration of both Tween-80 and Span-80. However, for the systems of calcium alginate/Q-12A/F-18A (A/Q/F), about 60% of the curcumin loaded in the beads was released at the end of experiments. The studies of scanning electron microscopy indicated that the microstructure of the walls of beads could significantly vary with the concentration or type of emulsifiers. The Fourier transform infrared spectral measurements confirmed that the interactions between calcium alginate and polyglycerol fatty acid esters were stronger than that between calcium alginate and Tween-80/Span-80. The results of swelling studies demonstrated that the initial rates of water uptake for A/Q/F beads were higher than that for A/S/T beads. Moreover, the data of release rates were fitted by an empirical equation, which showed that the release mechanism of curcumin from the alginate gels varied with the composition of emulsifiers for the A/S/T systems. This work provides an important insight into the effect of food emulsifiers on the release rates of the curcumin from calcium alginate beads and will be helpful for the application of the systems in controlled release of other hydrophobic drug.

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

    PubMed

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

    2005-07-01

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

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

    PubMed

    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.

  16. Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

    PubMed

    Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

    2008-02-28

    The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

  17. Immobilization of Escherichia coli novablue gamma-glutamyltranspeptidase in Ca-alginate-kappa-carrageenan beads.

    PubMed

    Hung, Chih-Peng; Lo, Huei-Fen; Hsu, Wen-Hwei; Chen, Shih-Chun; Lin, Long-Liu

    2008-08-01

    The recombinant Escherichia coli gamma-glutamyltranspeptidase (EcGGT) was immobilized in Ca-alginate-kappa-carrageenan beads. Effects of alginate concentration, amount of loading enzyme, and bead size on the entrapped activity were investigated. Optimum alginate concentration for EcGGT immobilization was found to be 2% (w/v). Using a loading enzyme concentration of 1.5 mg/g alginate, maximum enzyme activity was observed. With increase in bead size from 1.9 to 3.1 mm, the immobilization efficiency was decreased significantly because of mass transfer resistance. Thermal stability of the free EcGGT was increased as a result of the immobilization. Ca-alginate-kappa-carrageenan-EcGGT beads were suitable for up to six repeated uses, losing only 45% of their initial activity. Upon 30 days of storage the preserved activity of free and immobilized enzyme were found as 4% and 68%, respectively. The synthesis of L: -theanine was performed in 50 mM Tris-HCl buffer (pH 10) containing 25 mM L: -glutamine, 40 mM ethylamine, and 1.5 mg EcGGT/g alginate at 40 degrees C for 12 h, and a conversion rate of 27% was achieved.

  18. Chitosan coated alginate beads for the survival of microencapsulated Lactobacillus plantarum in pomegranate juice.

    PubMed

    Nualkaekul, Sawaminee; Lenton, Dominique; Cook, Michael T; Khutoryanskiy, Vitaliy V; Charalampopoulos, Dimitris

    2012-10-15

    This work studied the effect of multi-layer coating of alginate beads on the survival of encapsulated Lactobacillus plantarum in simulated gastric solution and during storage in pomegranate juice at 4°C. Uncoated, single and double chitosan coated beads were examined. The survival of the cells in simulated gastric solution (pH 1.5) was improved in the case of the chitosan coated beads by 0.5-2 logs compared to the uncoated beads. The cell concentration in pomegranate juice after six weeks of storage was higher than 5.5logCFU/mL for single and double coated beads, whereas for free cells and uncoated beads the cells died after 4 weeks of storage. In simulated gastric solution, the size of the beads decreased and their hardness increased with time; however, the opposite trend was observed for pomegranate juice, indicating that there is no correlation between cell survival and the hardness of the beads.

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

    PubMed

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

    2013-11-01

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

  20. Effect of immobilized cells in calcium alginate beads in alcoholic fermentation

    PubMed Central

    2013-01-01

    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. PMID:23721664

  1. Effect of immobilized cells in calcium alginate beads in alcoholic fermentation.

    PubMed

    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.

  2. Adipic acid dihydrazide treated partially oxidized alginate beads for sustained oral delivery of flurbiprofen.

    PubMed

    Maiti, Sabyasachi; Singha, Kamalika; Ray, Somasree; Dey, Paramita; Sa, Biswanath

    2009-01-01

    In this study, periodate oxidation of sodium alginate was controlled such that the oxidized alginate could form isolatable beads with Ca(+2) ions. The beads of oxidized alginate having a degree of oxidation 1 mol%, entrapped 89% flurbiprofen and released almost all of its content within 1.5 h in pH 7.2 phosphate buffer solution. The beads were covalently crosslinked with adipic dihydrazide (ADH) in addition to ionic crosslinks and were characterized. Scanning electron microscopy revealed that the beads were spherical having smooth surfaces. The drug entrapment efficiency decreased (90-86%) with increasing concentration of ADH (2-6% w/v) in the gelation medium. However, the beads prolonged the drug release in alkaline dissolution medium up to 8 h depending upon the concentration of ADH. The beads prepared with 2% ADH swelled more rapidly and led to faster drug release in either pH 1.2 HCl solution or pH 7.2 phosphate buffer solution. The swelling tendencies were reduced and the drug release became slower with higher concentrations in either fluid. The drug diffusion from the beads followed super case II transport mechanism. FTIR spectroscopy indicated stable nature of flurbiprofen in the beads and therefore had potential as sustained oral delivery system for the drug. PMID:19235554

  3. Survival of Bifidobacterium longum immobilized in calcium alginate beads in simulated gastric juices and bile salt solution.

    PubMed

    Lee, K Y; Heo, T R

    2000-02-01

    Bifidobacterium longum KCTC 3128 and HLC 3742 were independently immobilized (entrapped) in calcium alginate beads containing 2, 3, and 4% sodium alginate. When the bifidobacteria entrapped in calcium alginate beads were exposed to simulated gastric juices and a bile salt solution, the death rate of the cells in the beads decreased proportionally with an increase in both the alginate gel concentration and bead size. The initial cell numbers in the beads affected the numbers of survivors after exposure to these solutions; however, the death rates of the viable cells were not affected. Accordingly, a mathematical model was formulated which expressed the influences of several parameters (gel concentration, bead size, and initial cell numbers) on the survival of entrapped bifidobacteria after sequential exposure to simulated gastric juices followed by a bile salt solution. The model proposed in this paper may be useful for estimating the survival of bifidobacteria in beads and establishing optimal entrapment conditions.

  4. Stabilization of Aspergillus parasiticus cytosine deaminase by immobilization on calcium alginate beads improved enzyme operational stability.

    PubMed

    Zanna, H; Nok, A J; Ibrahim, S; Inuwa, H M

    2013-12-01

    Cytosine deaminase (CD) from Aspergillus parasiticus, which has half-life of 1.10 h at 37°C, was stabilized by immobilization on calcium alginate beads. The immobilized CD had pH and temperature optimum of 5 and 50°C respectively. The immobilized enzyme also stoichiometrically deaminated Cytosine and 5-fluorocytosine (5-FC) with the apparent K(M) values of 0.60 mM and 0.65 mM respectively, displaying activation energy of 10.72 KJ/mol. The immobilization of native CD on calcium alginate beads gave the highest yield of apparent enzymatic activity of 51.60% of the original activity and the enzymatic activity was lost exponentially at 37°C over 12 h with a half-life of 5.80 h. Hence, the operational stability of native CD can be improved by immobilization on calcium alginate beads.

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

    PubMed

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

    2013-01-01

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

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

    PubMed

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

    2013-04-01

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

  7. Hierarchically organization of biomineralized alginate beads for dual stimuli-responsive drug delivery.

    PubMed

    Yang, Liu; Shi, Jun; Zhou, Xiaofei; Cao, Shaokui

    2015-02-01

    Compartmentalized biomineralized alginate beads ranging from the micro to the visible scales with thermal- and pH-responsive drug delivery properties have been prepared via a one-step method in the present paper. Hollow multilayer microcapsules made of aliphatic poly(urethane-amine) (PUA) and sodium poly(styrenesulfonate) (PSS) serve as drug container to slow down the drug release. The results indicate that internal hollow multilayer microcapsules could hinder the permeation of the encapsulated Vitamin B2 (VB2) and retard the initial burst release of VB2. In addition, the drug release of compartmentalized biomineralized alginate beads exhibit distinguished pH- and thermal-dependent property due to pH-responsive alginate and the thermal-responsive aliphatic PUA. The drug release decreases when decreasing the pH value because the compact construction of alginate and biomineralized layer could prevent VB2 release from the beads. Moreover, the drug release is higher at 55 °C than that at 37 °C for the sake of the shrinkage of aliphatic PUA above its lower critical solution temperature (LCST). The results demonstrate that the compartmentalized biomineralized alginate beads show great potential as smart materials for controllable drug delivery.

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

    PubMed

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

    2013-04-01

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

  9. Immobilization of Bacillus amyloliquefaciens MBL27 cells for enhanced antimicrobial protein production using calcium alginate beads.

    PubMed

    Kumaravel, Vijayalakshmi; Gopal, Suseela Rajakumar

    2010-12-01

    Cell immobilization is one of the common techniques for increasing the overall cell concentration and productivity. Bacillus amyloliquefaciens MBL27 cells were immobilized in calcium alginate beads and it is a promising method for repeated AMP (antimicrobial protein) production. The present study aimed at determining the optimal conditions for immobilization of B. amyloliquefaciens MBL27 cells in calcium alginate beads and the operational stability for enhanced production of the AMP. AMP production with free and immobilized cells was also done. In batch fermentation, maximum AMP production (7300 AU (arbitrary units)/ml against Staphylococcus aureus) was obtained with immobilized cells in shake flasks under optimized parameters such as 3% (w/v) sodium alginate, 136 mM CaCl2 with 350 alginate beads/flask of 2.7-3.0 mm diameter. In repeated cultivation, the highest activity was obtained after the second cycle of use and approx. 94% production was noted up to the fifth cycle. The immobilized cells of B. amyloliquefaciens MBL27 in alginate beads are more efficient for the production of AMP and had good stability. The potential application of AMP as a wound healant and the need for development of economical methods for improved production make whole cell immobilization an excellent alternative method for enhanced AMP production.

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

    PubMed

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

    2014-03-10

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

  11. Adsorption of a cationic surfactant by a magsorbent based on magnetic alginate beads.

    PubMed

    Obeid, Layaly; El Kolli, Nadia; Dali, Noëlle; Talbot, Delphine; Abramson, Sébastien; Welschbillig, Mathias; Cabuil, Valérie; Bée, Agnès

    2014-10-15

    Adsorption of cetylpyridinium chloride (CPC), a cationic surfactant, by magnetic alginate beads (MagAlgbeads) was investigated. The magnetic adsorbent (called magsorbent) was prepared by encapsulation of magnetic functionalized nanoparticles in an alginate gel. The influence on CPC adsorption of several parameters such as contact time, pH and initial surfactant concentration was studied. The equilibrium isotherm shows that adsorption occurs through both electrostatic interactions with charge neutralization of the carboxylate groups of the beads and hydrophobic interactions inducing the formation of surfactant aggregates in the beads. The dosage of calcium ions released in the solution turns out to be a useful tool for understanding the adsorption mechanisms. Adsorption is accompanied by a shrinking of the beads that corresponds to a 45% reduction of the volume. Adsorption kinetic experiments show that equilibrium time is strongly dependent on the surfactant concentration, which monitors the nature of the interactions. On the other hand, since the pH affects the ionization state of adsorption sites, adsorption depends on the pH solution, maximum adsorption being obtained in a large pH range (3.2-12) in agreement with the pKa value of alginate (pKa=3.4-4.2). Finally, due to the formation of micelle-like surfactants aggregates in the magnetic alginate beads, they could be used as a new efficient magsorbent for hydrophobic pollutants. PMID:25086393

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

    PubMed

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

    2016-12-01

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

  13. Starch filler and osmoprotectants improve the survival of rhizobacteria in dried alginate beads.

    PubMed

    Schoebitz, Mauricio; Simonin, Hélène; Poncelet, Denis

    2012-01-01

    This work deals with optimising the cell survival of rhizobacteria encapsulated in alginate beads filled with starch. Immobilisation of rhizobacteria was done by dripping alginate-starch solution mixed with rhizobacteria into a calcium solution. Beads were analysed based on matrix formulation, bacteria growth phase, osmoprotectants and nature of calcium solution. Maximum cell recovery was obtained on Raoultella terrigena grown in medium supplemented with trehalose and calcium gluconate as gelling agent. Furthermore, dried beads containing Azospirillum brasilense presented 76% of viable cells after one year of storage. The survival of rhizobacteria during the bioencapsulation process can be improved by incorporating starch on beads composition, varying the growth phase of cells and using trehalose in growth culture medium. This work provides a selection of appropriate methods to improve the surviving rate of encapsulated cells during their production and long-term storage (∼1 year at 4°C).

  14. Immobilization of thermoalkalophilic recombinant esterase enzyme by entrapment in silicate coated Ca-alginate beads and its hydrolytic properties.

    PubMed

    Gülay, Seçkin; Şanlı-Mohamed, Gülşah

    2012-04-01

    Thermoalkalophilic esterase enzyme from Balçova (Agamemnon) geothermal site were aimed to be immobilized effectively via a simple and cost-effective protocol in silicate coated Calcium alginate (Ca-alginate) beads by entrapment. The optimal immobilization conditions of enzyme in Ca-alginate beads were investigated and obtained with 2% alginate using 0.5mg/ml enzyme and 0.7 M CaCl(2) solution. In order to prevent enzyme from leaking out of the gel beads, Ca-alginate beads were then coated with silicate. Enzyme loading efficiency and immobilization yield for silicate coated beads was determined as 98.1% and 71.27%, respectively and compared with non-coated ones which were 68.5% and 45.80%, respectively. Surface morphologies, structure and elemental analysis of both silicate coated and non-coated alginate beads were also compared using Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX). Moreover, silicate coated alginate beads enhanced reusability of esterase in continuous processes compared to non-coated beads. The hydrolytic properties of free and immobilized enzyme in terms of storage and thermal stability as well as the effects of the temperature and pH were determined. It was observed that operational, thermal and storage stabilities of the esterase were increased with immobilization. PMID:22309712

  15. Immobilization of thermoalkalophilic recombinant esterase enzyme by entrapment in silicate coated Ca-alginate beads and its hydrolytic properties.

    PubMed

    Gülay, Seçkin; Şanlı-Mohamed, Gülşah

    2012-04-01

    Thermoalkalophilic esterase enzyme from Balçova (Agamemnon) geothermal site were aimed to be immobilized effectively via a simple and cost-effective protocol in silicate coated Calcium alginate (Ca-alginate) beads by entrapment. The optimal immobilization conditions of enzyme in Ca-alginate beads were investigated and obtained with 2% alginate using 0.5mg/ml enzyme and 0.7 M CaCl(2) solution. In order to prevent enzyme from leaking out of the gel beads, Ca-alginate beads were then coated with silicate. Enzyme loading efficiency and immobilization yield for silicate coated beads was determined as 98.1% and 71.27%, respectively and compared with non-coated ones which were 68.5% and 45.80%, respectively. Surface morphologies, structure and elemental analysis of both silicate coated and non-coated alginate beads were also compared using Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX). Moreover, silicate coated alginate beads enhanced reusability of esterase in continuous processes compared to non-coated beads. The hydrolytic properties of free and immobilized enzyme in terms of storage and thermal stability as well as the effects of the temperature and pH were determined. It was observed that operational, thermal and storage stabilities of the esterase were increased with immobilization.

  16. Silver nanoparticle-alginate composite beads for point-of-use drinking water disinfection.

    PubMed

    Lin, Shihong; Huang, Rixiang; Cheng, Yingwen; Liu, Jie; Lau, Boris L T; Wiesner, Mark R

    2013-08-01

    Silver nanoparticles (AgNPs)-alginate composite beads were synthesized using three different approaches as filler materials of packed columns for simultaneous filtration-disinfection as an alternative portable water treatment process. The prepared composite beads were packed into a column through which Escherichia coli containing water was filtered to evaluate the disinfection efficacy. Excellent disinfection performance (no detectable viable colony) was achieved with a hydraulic retention time (HRT) as short as 1 min (the shortest tested) with the SGR (Simultaneous-Gelation-Reduction) and AR (Adsorption-Reduction) beads that were prepared using in situ reduction of Ag(+). Comparatively, the SGR beads released significantly less Ag(+)/AgNPs than the AR beads did within the same HRT. From the results of this study it was identified that SGR may be the best choice among all three different synthesis approaches in that the SGR beads can achieve satisfactory bactericidal performance with a relatively low material consumption rate.

  17. Swelling and drug release behavior of metformin HCl-loaded tamarind seed polysaccharide-alginate beads.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2016-01-01

    The paper describes the preparation, characterization, in vitro swelling and in vitro drug release of metformin HCl-loaded tamarind seed polysaccharide (TSP)-alginate beads were prepared by ionotropic-gelation technique and using CaCl2 as cross-linker. The prepared beads exhibited 32.73 ± 1.41% of drug loading (%), 94.86 ± 3.92% of drug encapsulation efficiency (%), and 1.24 ± 0.07 mm of average bead size. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the bead matrix was analyzed by FTIR analyses. These metformin HCl-loaded ionotropically gelled TSP-alginate beads demonstrated sustained in vitro drug release profile over 10h. These in vitro drug release exhibited pH-dependent drug release behavior. The in vitro drug release from these metformin HCl-loaded beads followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of these metformin HCl-loaded polymeric beads were found to be influenced by the pH of test mediums.

  18. Swelling and drug release behavior of metformin HCl-loaded tamarind seed polysaccharide-alginate beads.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2016-01-01

    The paper describes the preparation, characterization, in vitro swelling and in vitro drug release of metformin HCl-loaded tamarind seed polysaccharide (TSP)-alginate beads were prepared by ionotropic-gelation technique and using CaCl2 as cross-linker. The prepared beads exhibited 32.73 ± 1.41% of drug loading (%), 94.86 ± 3.92% of drug encapsulation efficiency (%), and 1.24 ± 0.07 mm of average bead size. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the bead matrix was analyzed by FTIR analyses. These metformin HCl-loaded ionotropically gelled TSP-alginate beads demonstrated sustained in vitro drug release profile over 10h. These in vitro drug release exhibited pH-dependent drug release behavior. The in vitro drug release from these metformin HCl-loaded beads followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of these metformin HCl-loaded polymeric beads were found to be influenced by the pH of test mediums. PMID:26472516

  19. Evaluation of the Effect of Psyllium on the Viability of Lactobacillus Acidophilus in Alginate-Polyl Lysine Beads

    PubMed Central

    Esmaeilzadeh, Jaleh; Nazemiyeh, Hossein; Maghsoodi, Maryam; Lotfipour, Farzaneh

    2016-01-01

    Purpose: Psylliumseeds are used in traditional herbal medicine to treat various disorders. Moreover, as a soluble fiber, psyllium has potential to stimulate bacterial growth in digestive system. We aimed to substitute alkali-extractable polysaccharides of psyllium for alginate in beads with second coat of poly-l-lysine to coat Lactobacillus acidophilus. Methods: Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique. Beads were characterized in terms of size, encapsulation efficiency, integrity and bacterial survival in harsh conditions. Results: Beads with narrow size distribution ranging from 1.85 ± 0.05 to 2.40 ± 0.18 mm with encapsulation efficiency higher than 96% were achieved. Psyllium concentrations in beads did not produce constant trend in bead sizes. Surface topography by SEM showed that substitution of psyllium enhanced integrity of obtained beads. Psyllium successfully protected the bacteria against acidic condition and lyophilization equal to alginate in the beads. Better survivability with beads of alginate/psyllium-poly-l-lysine was achieved with around 2 log rise in bacterial count in acid condition compared to the corresponding single coat beads. Conclusion: Alginate/psyllium (1:2) beads with narrow size distribution and high encapsulation efficiency of the bacteria have been achieved. Presence of psyllium produced a much smoother and integrated surface texture for the beads with sufficient protection of the bacteria against acidic condition as much as alginate. Considering the health benefits of psyllium and its prebiotic activity, psyllium can be beneficially replaced in part for alginate in probiotic coating. PMID:27766217

  20. Simultaneous removal of phenol, Cu and Cd from water with corn cob silica-alginate beads.

    PubMed

    Shim, Jaehong; Lim, Jeong-Muk; Shea, Patrick J; Oh, Byung-Taek

    2014-05-15

    Phenol and heavy metals in petroleum waste are environmental and human health concerns, but physicochemical removal is often cost-prohibitive and can produce toxic secondary products and treatment residues. An environmentally benign alternative combines corn cob silica with alginate and immobilized bacteria into beads for treating contaminated water. The concentration of phenol was decreased >92% by Pseudomonas putida YNS1 on aliginate-silica beads (2%, w/v) after equilibrating for 96h with water containing 214mg phenol/L. GC-MS analysis indicated formation of benzoquinone and other polar products. Beads containing corn cob silica decreased Cu concentrations by 84-88% and Cd by 83-87% within 24h. In a mixture of 114mg phenol, 43mg Cu and 51mg Cd/L, phenol removal (93% within 96h) only occurred with beads containing the silica and bacterial strain. Beads containing corn cob silica removed >97% of the Cu and >99% of the Cd, critical for reducing toxicity to the bacteria. Beads with the immobilized strain removed phenol when zeolite was used instead of corn cob silica, but beads with silica were more effective for Cu and Cd removal. Results show the potential of corn cob silica combined with alginate and immobilized bacteria for removing phenol and heavy metals from contaminated water. PMID:24685529

  1. Direct infection of Spodoptera litura by Photorhabdus luminescens encapsulated in alginate beads.

    PubMed

    Rajagopal, R; Mohan, Sharad; Bhatnagar, Raj K

    2006-09-01

    Actively growing cultures of Photorhabdus luminescens were encapsulated in sodium alginate beads and examined for their ability to infect insect hosts. These beads, containing approximately 2.5 x 10(7)Photorhabdus cells per bead, when mixed with sterilized soil and exposed to Spodoptera litura larvae resulted in 100% mortality in 48 h, while the use of alginate encapsulated Heterorhabditis nematode resulted in 40% mortality after 72 h. The bacteria were reisolated from the dead insect thus proving Koch's postulates and demonstrating the ability of P. luminescens to kill the insect host on their own, independent of the symbiont nematode. The LC(50) dose of Photorhabdus cells was estimated at 1010 cells per larva for killing S. litura 6th instar larvae in 48 h.

  2. Entrapment of iron nanoparticles in calcium alginate beads for groundwater remediation applications.

    PubMed

    Bezbaruah, Achintya N; Krajangpan, Sita; Chisholm, Bret J; Khan, Eakalak; Bermudez, Juan J Elorza

    2009-07-30

    Zero-valent iron nanoparticles (nZVI) have been successfully entrapped in biopolymer, calcium (Ca)-alginate beads. The study has demonstrated the potential use of this technique in environmental remediation using nitrate as a model contaminant. Ca-alginate beads show promise as an entrapment medium for nZVI for possible use in groundwater remediation. Based on scanning electron microscopy images it can be inferred that the alginate gel cluster acts as a bridge that binds the nZVI particles together. Kinetic experiments with 100, 60, and 20mg NO(3)(-)-NL(-1) indicate that 50-73% nitrate-N removal was achieved with entrapped nZVI as compared to 55-73% with bare nZVI over a 2-h period. The controls ran simultaneously show little NO(3)(-)-N removal. Statistical analysis indicates that there was no significant difference between the reaction rates of bare and entrapped nZVI. The authors have shown for the first time that nZVI can be effectively entrapped in Ca-alginate beads and no significant decrease in the reactivity of nZVI toward the model contaminant (nitrate here) was observed after the entrapment.

  3. Tapioca starch blended alginate mucoadhesive-floating beads for intragastric delivery of Metoprolol Tartrate.

    PubMed

    Biswas, Nikhil; Sahoo, Ranjan Kumar

    2016-02-01

    The objective of the study was to develop tapioca starch blended alginate mucoadhesive-floating beads for the intragastric delivery of Metoprolol Tartrate (MT). The beads were prepared by ionotropic gelation method using calcium chloride as crosslinker and gas forming calcium carbonate (CaCO3) as floating inducer. The alginate gel beads having 51-58% entrapped MT showed 90% release within 45 min in gastric medium (pH 1.2). Tapioca starch blending markedly improved the entrapment efficiency (88%) and sustained the release for 3-4 h. A 12% w/w HPMC coating on these beads extended the release upto 9-11 h. In vitro wash off and buoyancy test in gastric media revealed that the beads containing CaCO3 has gastric residence of more than 12 h. In vitro optimized multi-unit formulation consisting of immediate and sustained release mucoadhesive-floating beads (40:60) showed good initial release of 42% MT within 1h followed by a sustained release of over 90% for 11 h. Pharmacokinetic study performed in rabbit model showed that the relative oral bioavailability of MT after administration of oral solution, sustain release and optimized formulation was 51%, 67% and 87%, respectively. Optimized formulation showed a higher percent inhibition of isoprenaline induced heart rate in rabbits for almost 12 h.

  4. Formulation optimization and evaluation of jackfruit seed starch-alginate mucoadhesive beads of metformin HCl.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar

    2013-08-01

    The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration.

  5. Formulation optimization and evaluation of jackfruit seed starch-alginate mucoadhesive beads of metformin HCl.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar

    2013-08-01

    The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. PMID:23628586

  6. Preservation of viability and antibacterial activity of Lactobacillus spp. in calcium alginate beads.

    PubMed

    Brachkova, Mariya I; Duarte, Maria A; Pinto, João F

    2010-12-23

    The objective of the study was to produce calcium alginate beads able to deliver Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus bulgaricus and Lactobacillus lactis) with preserved viability and antibacterial activity. Four types of beads, containing entrapped (E), surface and entrapped (ES), surface (S) and concentrated surface and entrapped lactobacilli (C(ES)) were prepared and physically characterized. The antibacterial activity of lactobacilli cultures before and after immobilization, freeze-drying and throughout storage was studied in relationship to the viable number of lactobacilli. Multi-resistant clinical isolates (methicillin-resistant Staphylococcus aureus, vancomycine-resistant Enterococcus faecalis, VIM-2-metalo-β-lactamase producing Pseudomonas aeruginosa and CTX-M-15-β-lactamase producing strains: Escherichia coli and Klebsiella pneumoniae) were used as indicator strains. Alginate beads in which lactobacilli proliferated to the beads surface (ES and C(ES)) differed significantly from the other types of beads in their physicochemical properties, showing smoother surface morphology, more spherical shape, bigger weight, lower calcium content, density and crushing force. Lactobacilli cultures, at high cell concentrations (10(8)cfu/ml) were active against both Gram-positive and negative multi-resistant bacteria. Beads containing both entrapped and surface lactobacilli (ES) resulted in viability and antibacterial activity most similar to non-processed lactobacilli cultures. The viability and antibacterial activity of the immobilized lactobacilli remained stable after 6 months storage.

  7. Optimizing alginate beads for the immobilisation of Phaeodactylum tricornutum in estuarine waters.

    PubMed

    Cabrita, Maria Teresa; Raimundo, Joana; Pereira, Patrícia; Vale, Carlos

    2013-01-01

    This study addresses the influence of calcium as hardening agent, on alginate gel bead stability and suitability for the growth of Phaeodactylum tricornutum Bohlin (Bacillariophyceae) in estuarine waters. Alginate beads produced with 1, 2, 4, 5 and 6% of CaCl2 solutions were investigated for stability and suitability for growth of P. tricornutum cells, under mean salinity 27, at 220 and 440 rpm stirring laboratory conditions, and in devices placed under in situ estuarine conditions. Gel stability and suitability for cell growth were evaluated through bead diameter, bead disruption, dissolution and loss of spherical shape, cell viability and specific growth rates. Beads gelled with 5% CaCl2 were found the most suitable to sustain gel stability and cell growth in the estuarine waters. These beads were surveyed during dredging operations in the Tagus estuary, both in situ and in estuarine water under laboratory conditions, showing significantly lowered growth rates possibly due to Mn, Co and As accumulated in the cells. Results confirmed that the monitoring tool presented is reliable and effective for the assessment of anthropogenic impacts.

  8. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    PubMed

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect.

  9. pH-dependent release property of alginate beads containing calcium carbonate particles.

    PubMed

    Han, M R; Kwon, M C; Lee, H Y; Kim, J C; Kim, J D; Yoo, S K; Sin, I S; Kim, S M

    2007-12-01

    Alginate bead containing calcium carbonate particle were prepared by dropping the suspension of alginate/calcium carbonate (4/1, w/w) into aqueous solution of CaCl(2) (0.1 M). The pH-dependent release property of the bead was observed for 12 h using blue dextran as a model drug. The release increased up to 4 h in a saturation manner. When no calcium carbonate was contained, the release exhibited no marked variation with pH and the values were 27-39%. On the other hand, in case calcium carbonate was included in the matrix of alginate beads, intensive release(40-50%) was achieved in acidic and neutral conditions and the degrees of release were suppressed in alkali conditions and the values were approximately 20%. The pH-sensitive release property is possibly because the particles of calcium carbonate embedded in the matrix of beads were leached out in acidic and neutral conditions, leaving cavities in the matrix. The cavities are likely to be main pathways for the release of blue dextran.

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

    PubMed

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

    2015-11-17

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

  11. Water status and thermal analysis of alginate beads used in cryopreservation of plant germplasm.

    PubMed

    Block, William

    2003-08-01

    Encapsulation and dehydration techniques using alginate beads are used increasingly for the pre-treatment of various plant materials for cryopreservation to improve survival post-cryogenic storage. This study reports the effects of the water content of beads (formed with 3% (w/v) alginic acid in liquid S-RIB), polymerisation time (in 100 mM calcium chloride solution), osmotic dehydration (in 0.75 M sucrose solution), and evaporative air desiccation on the thermal properties of alginate beads used in cryopreservation protocols. Experimental beads were assayed using a differential scanning calorimeter (DSC) with a cooling programme to -150 degrees C, followed by re-warming. Resultant thermograms were evaluated with particular reference to the onset temperature and enthalpy of the melt endotherm from which the quantities of frozen and unfrozen water were calculated. Treatments were applied sequentially to samples of beads and their thermal features evaluated at each stage of the protocol. Using 'standard' beads (40-55 mg fresh weight), formed using plastic disposable pipettes, the degree of polymerisation (>10 min) proportionally reduced their dry weight and increased their water content. Thermal characteristics of the beads were unaffected by polymerisation times >10 min, but the maximum level (23%) of unfrozen (osmotically inactive) water was achieved after 15 min polymerisation. Osmotic dehydration using 0.75 M sucrose significantly lowered bead water content and mean dry weight approximately doubled with 20-24 h immersion time. Bead desiccation in still air reduced their water content by 83% of fresh weight, whilst dry weight remained constant. After 8 h desiccation in air between 27 and 37% of the water in the bead was osmotically inactive (unfrozen) in DSC scans. Desiccation >18 h reduced this fraction to zero. The melt onset temperature and the enthalpy of melting were directly related to bead water content. The unfrozen water fraction increased substantially

  12. Removal of arsenic from drinking water by ferric hydroxide microcapsule-loaded alginate beads in packed adsorption column.

    PubMed

    Sarkar, Priyabrata; Pal, Priyabrata; Bhattacharyay, Dipankar; Banerjee, Suchanda

    2010-11-01

    In this paper we have presented a unique low cost arsenic removal technique using ferric hydroxide microcapsule-loaded alginate beads (FHMCA) as an adsorbent in a continuous packed column. The microencapsulated particles of ferric hydroxide were produced in a spray dryer and subsequently coated with calcium alginate to form spherical beads of about 2 mm diameter. Batch experiments were conducted with these beads to generate isotherm data. The loading capacity was found to be 3.8 mg arsenic/gm of adsorbent. The experimental data conformed to Freundlich adsorption isotherm. A generalized mathematical model was also developed and the visual basic codes run with the physical parameters of the adsorbent and isotherm data that were evaluated experimentally was achieved for a continuous 75 days' operation. The safe disposal of the spent adsorbent was confirmed by the toxicity characteristic leaching procedure (TCLP) results. With known set of physical parameters of the adsorbent, input water flow rate and its arsenic concentration, the model could predict the number of days the column would run with output below a specific arsenic concentration.

  13. Hydrous ferric oxide doped alginate beads for fluoride removal: Adsorption kinetics and equilibrium studies

    NASA Astrophysics Data System (ADS)

    Sujana, M. G.; Mishra, A.; Acharya, B. C.

    2013-04-01

    A new biopolymer beads, composite of hydrous ferric oxide (HFO) and alginate were synthesised, characterised and studied for its fluoride efficiency from water. The beads were characterised by chemical analysis, BET surface area, pHPZC and X-ray diffraction (XRD) analysis. The optimum conditions for fluoride removal were determined by studying operational variables viz. pH, contact time, initial F- concentration, bead dose and temperature. Presence of other anions like SO42-, PO43-, NO3-, Cl- and HCO3- effect on fluoride removal efficiency of prepared beads was also tested. The beads were 0.8-0.9 mm in size and contain 32-33% Fe (III) and showed specific surface area of 25.80 m2 g-1 and pHPZC of 5.15. Modified beads demonstrated Langmuir F- adsorption capacity of 8.90 mg g-1 at pH 7.0. The adsorption kinetics were best described by the pseudo-second order kinetic model followed by intra-particle diffusion as the rate determining step. It was found that about 80% of the adsorbed fluoride could be desorbed by using 0.05 M HCl. The FTIR, Raman and SEM-EDAX analysis were used to study the fluoride adsorption mechanisms on beads. Studies were also conducted to test the potential application of beads for F- removal from drinking water and the treated water quality.

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

    PubMed

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

    2004-01-01

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

  15. Comparative study of calcium alginate, activated carbon, and their composite beads on methylene blue adsorption.

    PubMed

    Hassan, A F; Abdel-Mohsen, A M; Fouda, Moustafa M G

    2014-02-15

    Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

    Ozseker, Emine Erdogan; Akkaya, Alper

    2016-10-20

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

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

    PubMed

    Ozseker, Emine Erdogan; Akkaya, Alper

    2016-10-20

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

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

    PubMed Central

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

    2016-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  1. Boron removal from aqueous solutions using alginate gel beads in fixed-bed systems

    PubMed Central

    Demey-Cedeño, Hary; Ruiz, Montserrat; Barron-Zambrano, Jesús Alberto; Sastre, Ana Maria

    2014-01-01

    Background A column sorption study was carried out using calcium alginate gel beads as adsorbent for the removal of boron from aqueous solutions. The breakthrough curve was obtained as a function of pH, initial concentration of boron, feed flow rate, adsorbent mass and column diameter. The breakthrough capacity values and adsorption percentage of calcium alginate gel for boron were calculated. Column data obtained at different conditions were described using the Adams–Bohart model and bed-depth service time (BDST), derived from the Adams–Bohart equation to predict breakthrough curves and to determine the characteristic column parameters required for process design. Results The maximum adsorption percentage of boron on calcium alginate gel beads using an initial concentration of boron of 50 mg L−1 at pH 11 and room temperature (20±1°C) was calculated to be 55.14%. Conclusion The results indicated that calcium alginate can be used in a continuous packed-bed column for boron adsorption. The optimal conditions for boron adsorption were obtained at high pH, higher initial boron concentration, increased column depth and lower flow velocity. © 2014 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25821332

  2. Modified alginate beads for mucoadhesive drug delivery system: an updated review of patents.

    PubMed

    Swain, Suryakanta; Behera, Aurobinda; Beg, Sarwar; Patra, Chinam N; Dinda, Subash C; Sruti, Jammula; Rao, Muddana E B

    2012-12-01

    Pharmaceutical research and inventions are increasingly developed for the design of an ideal dosage regimen in drug therapy of many diseases, which attains therapeutic concentration of drug in plasma and maintains it constant for the entire duration of treatment and also minimizes the side effects. Recent trends in pharmaceutical technology indicated that mucoadhesive micro particle and modified alginate beads as drug delivery system especially suitable for achieving delivery of drug in a predetermined rate locally or systemically for a prolonged period of time. The release of drug from microparticle depends on a variety of factors including carrier used to form the micro particle and amount of drug contained in them. The main aim of the present review is to explain the various theories, mechanisms, advanced mucoadhesive polymers, various delivery approaches, methodologies for developing a mucoadhesive micro-particle and modified alginate beads formulation, in vitro, ex vivo and in vivo characterization. Apart from this, an innovative test method that is biacore is highlighted in this review to measure the mucoadhesive strength. This review is also briefly explained about the updated patenting system for the development of micro-particle and modified alginate beads as drug delivery system.

  3. Kinetics of fungal extracellular alpha-amylase from Fusarium solani immobilized in calcium alginate beads.

    PubMed

    Kumar, Devendra; Muthukumar, M; Garg, Neelima

    2012-11-01

    Extracellular alpha-amylase mass produced by Fusarium solani using mango kernel as substrate was immobilized in calcium alginate beads through entrapment technique. Maximum enzyme immobilization efficiency was achieved in 2 mm size beads formed by 6.5% (w/v) of sodium alginate in 2% (w/v) calcium chloride. The catalytic properties of the immobilized alpha-amylase were compared with that of free enzyme (soluble). The activity yield of the immobilized enzyme was 81% of the free enzyme. The immobilized enzyme showed optimum activityat pH 4.5-6.0 and temperature 40 degrees C, in contrast to the free enzyme at 5.5 and 30 degrees C, respectively. Thermal stability of the immobilized enzyme was found to be more than the free enzyme over a longer time interval. The immobilized enzyme retained activity upto 20% of optimum even after 180 min. While the free enzyme lost its 80% activity after 60 min and lost total activity down to zero by 120 min. The kinetic constants, viz., K(M) (Michaelis constant), V(max) and activation energy were affected by immobilization. However, the immobilized alpha-amylase in calcium alginate beads supports its long-term storage which has immense industrial applications.

  4. NMR microscopy of heavy metal absorption in calcium alginate beads

    SciTech Connect

    Nestle, N.; Kimmich, R.

    1996-01-01

    In recent years, heavy metal uptake by biopolymer gels, such as Cal-Alginate or chitosan, has been studied by various methods. This is of interest because such materials might be an alternative to synthetical ion-exchange resins in the treatment of industrial waste waters. Most of the work done in this field consisted of studies of equilibrium absorption of different heavy metal ions with dependence on various experimental parameters. In some publications, the kinetics of absorption were studied, too. However, no experiments on the spatial distribution of heavy metals during the absorption process are known to us. Using Cu as an example, it is demonstrated in this article that NMR microscopy is an appropriate tool for such studies. By the method presented here, it is possible to monitor the spatial distribution of heavy metal ions with a time resolution of about 5 min and a spatial resolution of 100 {mu}m or even better. 14 refs., 10 figs.

  5. Alginate/magnetite hybrid beads for magnetically stimulated release of dopamine.

    PubMed

    Kondaveeti, Stalin; Cornejo, Daniel R; Petri, Denise Freitas Siqueira

    2016-02-01

    Hybrid beads composed of magnetite nanoparticles (MNP) and alginate (Alg) were synthesized and coded as Alg-MNP. They were incubated in dopamine (DOPA) solution (5 g/L), at pH 7.4 and 8 °C, during 12 h, promoting the DOPA loaded magnetic beads, coded as Alg-MNP/DOPA. The release of DOPA was further evaluated in the absence and the presence of external magnetic field (EMF) of 0.4 T. The products Alg-MNP and Alg-MNP/DOPA were characterized by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared vibrational spectroscopy (FTIR), UV spectrophotometry, thermogravimetric analyses (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) analyses and superconducting quantum interference device (SQUID) magnetometer. The magnetic and chemical properties of Alg-MNP beads were not affected by DOPA loading. The incorporation of DOPA into the beads depended on the pH and on the negative charge density. At pH 7.4 38% of DOPA were loaded into Alg-MNP beads, whereas at pH 2 or using neat Alg beads (lower charge density than Alg-MNP) the loading efficiency decreased to one third or less. In the absence of EMF, 24% of the loaded DOPA was released from Alg-MNP at pH 7.4 over a period of 26 h. The released amount increased to 33% under the stimulus of EMF. A model was proposed to explain the loading efficiency of charged drugs, as DOPA, into hybrid beads and the role played by EMF on delivery systems, where drug and matrix are oppositely charged. The results suggest that the alginate combined with magnetite nanoparticles is a promising system for release of DOPA in the presence of EMF.

  6. Impact of gelation period on modified locust bean-alginate interpenetrating beads for oral glipizide delivery.

    PubMed

    Dey, Paramita; Sa, Biswanath; Maiti, Sabyasachi

    2015-05-01

    In this work, the effect of hydrogelation period in the design of glipizide-loaded biopolymer-based interpenetrating network (IPN) beads was investigated. Carboxymethyl locust bean gum and sodium alginate IPN beads were prepared by ionic crosslinking method using aqueous aluminium chloride salt solution as gelation medium. The longer exposure of the IPN beads in the gelation medium caused a considerable loss of the drug (∼ 8%), and also affected their surface morphology and drug release performance. Spherical shape of the IPN beads was observed under scanning electron microscope (SEM). The diameter of IPN beads increased with increasing gelation time. The IPNs cured for 0.5h exhibited slower drug release kinetics in HCl (pH 1.2) and phosphate buffer (pH 7.4) solution than those incubated for 1-2h. The drug release occurred at a faster rate in phosphate buffer solution and continued for a minimum period of 8h. The IPNs cured for the lowest period obeyed polymer chain-relaxation phenomenon as dominating mechanism for drug release. However, all the IPNs followed anomalous mechanism of drug transport. The drug release corroborated well with pH-dependent swelling behaviors of the IPNs. Thus, IPN beads cured for 0.5h were found most suitable for controlled delivery of BCS class II anti-diabetic drug glipizide. PMID:25745842

  7. Development and evaluation of alginate-chitosan gastric floating beads loading with oxymatrine solid dispersion.

    PubMed

    Liu, Yanhua; Chen, Lihong; Zhou, Chengming; Yang, Jianhong; Hou, Yanhui; Wang, Wenping

    2016-01-01

    Oxymatrine (OM) can be metabolized to matrine in gastrointestinal ileocecal valve after oral administration, which affects pharmacological activity and reduce bioavailability of OM. A type of multiple-unit alginate-chitosan (Alg-Cs) floating beads was prepared by the ionotropic gelation method for gastroretention delivery of OM. A solid dispersion technique was applied and incorporated into beads to enhance the OM encapsulation efficiency (EE) and sustain the drug release. The surface morphology and internal hollow structure of beads were evaluated using optical microscopy and scanning electron microscopy (SEM). The developed Alg-Cs beads were spherical in shape with hollow internal structure and had particle size of 3.49 ± 0.09 mm and 1.33 ± 0.09 mm for wet and dried beads. Over 84% of the optimized OM solid dispersion-loaded Alg-Cs beads were able to continuously float over the simulated gastric fluid for 12 h in vitro. The OM solid dispersion-loaded Alg-Cs beads showed drug EE of 67.07%, which was much higher than that of beads loading with pure OM. Compared with the immediate release of OM capsules and pure OM-loaded beads, the release of OM from solid dispersion-loaded Alg-Cs beads was in a sustained-release manner for 12 h. Prolonged gastric retention time of over 8.5 h was achieved for OM solid dispersion-loaded Alg-Cs floating beads in healthy rabbit in in vivo floating ability evaluated by X-ray imaging. The developed Alg-Cs beads loading with OM solid dispersion displayed excellent performance features characterized by excellent gastric floating ability, high drug EE and sustained-release pattern. The study illustrated the potential use of Alg-Cs floating beads combined with the solid dispersion technique for prolonging gastric retention and sustaining release of OM, which could provide a promising drug delivery system for gastric-specific delivery of OM for bioavailability enhancement.

  8. Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II) and Pb(II)

    PubMed Central

    Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

    2016-01-01

    Alginate and algal-biomass (Laminaria digitata) beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine) (PEI) was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX): the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying) on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g−1 and 112, 77 and 67 mg Cu g−1 for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads), the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions. PMID:27598128

  9. Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II) and Pb(II).

    PubMed

    Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

    2016-01-01

    Alginate and algal-biomass (Laminaria digitata) beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine) (PEI) was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX): the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying) on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g(-1) and 112, 77 and 67 mg Cu g(-1) for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads), the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions. PMID:27598128

  10. Adsorptive removal of patulin from apple juice using Ca-alginate-activated carbon beads.

    PubMed

    Yue, Tianli; Guo, Caixia; Yuan, Yahong; Wang, Zhouli; Luo, Ying; Wang, Ling

    2013-10-01

    This study aimed to investigate the adsorption of patulin from apple juice by Ca-alginate-activated carbon (Ca-alginate-AC) beads. The capacity of patulin was determined by high-performance liquid chromatography. The results showed that Ca-alginate-AC beads have significant ability to reduce patulin from contaminated apple juice. Furthermore, the adsorption process did not affect the quality of apple juice. The effects of contact time, initial patulin concentration, adsorbent dose, and temperature were assessed. The removal percentage of patulin increased with contact time, adsorbent dose, and temperature. A reduction was also noted to bind patulin at increased levels of contamination. The equilibrium data were fitted to Langmuir, Freundlich, and Temkin isotherm models and the isotherm constants were calculated at different temperatures. The adsorption equilibrium was best described by the Freundlich isotherm (R(2) > 0.990). The pseudo 1st-order model was found to describe the kinetic data satisfactorily. Thermodynamic parameters such as standard Gibbs free energy (ΔG◦◦), standard enthalpy (ΔH◦), and standard entropy (ΔS◦) were evaluated. The results showed that the adsorption was spontaneous and endothermic nature.

  11. Biodegradation of crystal violet using Burkholderia vietnamiensis C09V immobilized on PVA-sodium alginate-kaolin gel beads.

    PubMed

    Cheng, Ying; Lin, HongYan; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

    2012-09-01

    The strain, Burkholderia vietnamiensis C09V was immobilized on PVA-alginate-kaolin gel beads as a biomaterial to improve the degradation of crystal violet from aqueous solution. The results show that 98.6% (30 mg L(-1)) crystal violet was removed from aqueous solution using immobilized cells on PVA-alginate-kaolin gel beads, while 94.0% crystal violet was removed by free cells after degradation at the pH 5 and 30°C for 30 h. Kinetics studies show that the pseudo-second-order kinetics well described the adsorption of crystal violet on the PVA-alginate-kaolin beads. Biodegradation of crystal violet on immobilized cells was fitted well by first-order reaction kinetics, indicating that CV was adsorbed onto kaolin and followed their degradation by immobilized cells onto the the PVA-alginate-kaolin beads. Characterization with SEM shows that cells attached well to the surface of PVA-alginate-kaolin beads, leading to improved crystal violet transfer from aqueous solution to immobilized cells. In addition, UV-vis show that the absorption peak at 588 nm was reduced by the degraded N-bond linkages, as well as the formation of degrading products were observed by Fourier transform infrared (FTIR). These results suggest that crystal violet was biodegraded to N,N-dimethylaminophenol and Michler's Ketone prior to these intermediates being further degraded. PMID:22789742

  12. Biodegradation of crystal violet using Burkholderia vietnamiensis C09V immobilized on PVA-sodium alginate-kaolin gel beads.

    PubMed

    Cheng, Ying; Lin, HongYan; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

    2012-09-01

    The strain, Burkholderia vietnamiensis C09V was immobilized on PVA-alginate-kaolin gel beads as a biomaterial to improve the degradation of crystal violet from aqueous solution. The results show that 98.6% (30 mg L(-1)) crystal violet was removed from aqueous solution using immobilized cells on PVA-alginate-kaolin gel beads, while 94.0% crystal violet was removed by free cells after degradation at the pH 5 and 30°C for 30 h. Kinetics studies show that the pseudo-second-order kinetics well described the adsorption of crystal violet on the PVA-alginate-kaolin beads. Biodegradation of crystal violet on immobilized cells was fitted well by first-order reaction kinetics, indicating that CV was adsorbed onto kaolin and followed their degradation by immobilized cells onto the the PVA-alginate-kaolin beads. Characterization with SEM shows that cells attached well to the surface of PVA-alginate-kaolin beads, leading to improved crystal violet transfer from aqueous solution to immobilized cells. In addition, UV-vis show that the absorption peak at 588 nm was reduced by the degraded N-bond linkages, as well as the formation of degrading products were observed by Fourier transform infrared (FTIR). These results suggest that crystal violet was biodegraded to N,N-dimethylaminophenol and Michler's Ketone prior to these intermediates being further degraded.

  13. Alginate bead fabrication and encapsulation of living cells under centrifugally induced artificial gravity conditions.

    PubMed

    Haeberle, Stefan; Naegele, Lars; Burger, Robert; von Stetten, Felix; Zengerle, Roland; Ducrée, Jens

    2008-06-01

    This study presents a novel method for the direct, centrifugally induced fabrication of small, Ca2+-hardened alginate beads at polymer-tube micronozzles. The bead diameter can arbitrarily be adjusted between 180-800 microm by the nozzle geometry and spinning frequencies between 5-28 Hz. The size distribution of the main peak features a CV of 7-16%, only. Up to 600 beads per second and channel are issued from the micronozzle through an air gap towards the curing agent contained in a standard lab tube ('Eppi'). Several tubes can be mounted on a 'flying bucket' rotor where they align horizontally under rotation and return to a vertical position as soon as the rotor is at rest. The centrifugally induced, ultra-high artificial gravity conditions (up to 180 g) even allow the micro-encapsulation of alginate solutions displaying viscosities up to 50 Pa s, i.e. approximately 50,000 times the viscosity of water! With this low cost technology for microencapsulation, HN25 and PC12 cells have successfully been encapsulated while maintaining vitality.

  14. Characterization of dextransucrase immobilized on calcium alginate beads from Leuconostoc mesenteroides PCSIR-4.

    PubMed

    Ul Qader, Shah Ali; Aman, Afsheen; Syed, Noman; Bano, Saeeda; Azhar, Abid

    2007-06-01

    Immobilization of dextransucrase from Leuconostoc mesenteroides PCSIR-4 on alginate is optimized for application in the production of dextran from sucrose. Dextransucrase was partially purified by ethanol upto 2.5 fold. Properties of dextransucrase were less affected by immobilization on alginate beads from soluble enzyme. Highest activities of both soluble and immobilized dextransucrase found to be at 35 degrees C and optimum pH for activity remain 5.00. Substrate maxima for immobilized enzyme changed from 125 mg/ml to 200 mg/ml. Incubation time for enzyme-substrate reaction for maximum enzyme activity was increased from 15 minutes to 60 minutes in case of immobilized enzyme. Maximum stability of immobilized dextransucrase was achieved at 25 degrees C with respect to time.

  15. A study towards release dynamics of thiram fungicide from starch-alginate beads to control environmental and health hazards.

    PubMed

    Singh, Baljit; Sharma, D K; Gupta, Atul

    2009-01-15

    In order to make the judicious use of thiram fungicide we have developed starch- and alginate-based controlled and sustained agrochemical delivery system in the form of beads using calcium chloride (CaCl2) as crosslinker. The beads were characterized by FTIR and swelling studies. To study the effect of composition of the beads on the release dynamics of fungicide (thiram), beads were prepared by varying the amount of starch, alginate and crosslinker in the beads. Formulation characteristics like entrapment efficiency, bead size, percentage equilibrium swelling of the beads and diffusion mechanism for thiram release have been evaluated. Maximum (93.33+/-2.89)% swelling and maximum (80.67+/-0.83)% thiram release has occurred in the beads prepared with 15% starch, 1% alginate and 0.1M crosslinker solution. In most of the formulations the entrapment efficacy of thiram has been observed more than 90% and the values for the diffusion exponent 'n' have been obtained >1 which shows that the release of fungicides occurred through Case II diffusion mechanism.

  16. Determination of diffusion coefficients and diffusion characteristics for chlorferon and diethylthiophosphate in Ca-alginate gel beads.

    PubMed

    Ha, Jiyeon; Engler, Cady R; Lee, Seung Jae

    2008-07-01

    Diffusion characteristics of chlorferon and diethylthiophosphate (DETP) in Ca-alginate gel beads were studied to assist in designing and operating bioreactor systems. Diffusion coefficients for chlorferon and DETP in Ca-alginate gel beads determined at conditions suitable for biodegradation studies were 2.70 x 10(-11) m(2)/s and 4.28 x 10(-11) m(2)/s, respectively. Diffusivities of chlorferon and DETP were influenced by several factors, including viscosity of the bulk solution, agitation speed, and the concentrations of diffusing substrate and immobilized cells. Diffusion coefficients increased with increasing agitation speed, probably due to poor mixing at low speed and some attrition of beads at high speeds. Diffusion coefficients also increased with decreasing substrate concentration. Increased cell concentration in the gel beads caused lower diffusivity. Theoretical models to predict diffusivities as a function of cell weight fraction overestimated the effective diffusivities for both chlorferon and DETP, but linear relations between effective diffusivity and cell weight fraction were derived from experimental data. Calcium-alginate gel beads with radii of 1.65-1.70 mm used in this study were not subject to diffusional limitations: external mass transfer resistances were negligible based on Biot number calculations and effectiveness factors indicated that internal mass transfer resistance was negligible. Therefore, the degradation rates of chlorferon and DETP inside Ca-alginate gel beads were reaction-limited. PMID:18080347

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

    PubMed

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

    2013-05-01

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

  18. Encapsulated human hepatocellular carcinoma cells by alginate gel beads as an in vitro metastasis model

    SciTech Connect

    Xu, Xiao-xi; Liu, Chang; Liu, Yang; Li, Nan; Guo, Xin; Wang, Shu-jun; Sun, Guang-wei; Wang, Wei; Ma, Xiao-jun

    2013-08-15

    Hepatocellular carcinoma (HCC) is the most common primary liver cancer and often forms metastases, which are the most important prognostic factors. For further elucidation of the mechanism underlying the progression and metastasis of HCC, a culture system mimicking the in vivo tumor microenvironment is needed. In this study, we investigated the metastatic ability of HCC cells cultured within alginate gel (ALG) beads. In the culture system, HCC cells formed spheroids by proliferation and maintained in nuclear abnormalities. The gene and protein expression of metastasis-related molecules was increased in ALG beads, compared with the traditional adhesion culture. Furthermore, several gene expression levels in ALG bead culture system were even closer to liver cancer tissues. More importantly, in vitro invasion assay showed that the invasion cells derived from ALG beads was 7.8-fold higher than adhesion cells. Our results indicated that the in vitro three-dimensional (3D) model based on ALG beads increased metastatic ability compared with adhesion culture, even partly mimicked the in vivo tumor tissues. Moreover, due to the controllable preparation conditions, steady characteristics and production at large-scale, the 3D ALG bead model would become an important tool used in the high-throughput screening of anti-metastasis drugs and the metastatic mechanism research. -- Highlights: •We established a 3D metastasis model mimicking the metastatic ability in vivo. •The invasion ability of cells derived from our model was increased significantly. •The model is easy to reproduce, convenient to handle, and amenable for large-scale.

  19. Simultaneous detection and removal of radioisotopes with modified alginate beads containing an azo-based probe using RGB coordinates.

    PubMed

    Jo, Ara; Jang, Geunseok; Namgung, Ho; Kim, Choongho; Kim, Daigeun; Kim, Yujun; Kim, Jongho; Lee, Taek Seung

    2015-12-30

    We prepared alginate beads that were modified with an azo-based probe molecule to monitor simultaneously the removal (by alginate) and probing (by the azo-probe molecule) of radioisotopes such as cobalt, strontium, and cesium ions. As an azo-probe molecule, Basic Orange 2 (BO2) was immobilized to the alginate bead. The BO2 in aqueous solution exhibited a slight red shift in absorption with a change in color from orange to dark orange upon addition of cobalt and strontium ions. In contrast, the color of BO2 did not change upon exposure to cesium ions. Thus, the covalently embedded BO2 in alginate beads could adsorb cobalt and strontium ions resulting in recognizable color change of the beads, which was induced by the formation of a complex between BO2 and metal ions. The color changes of the beads in the presence of metal ions were determined quantitatively using RGB color coordinate values. In addition to effectively removing metal ions, the colorimetric coordinate method provides a convenient and simple sensing technique for naked-eye metal ion detection. PMID:26188865

  20. Chemical oxidation of a malodorous compound, indole, using iron entrapped in calcium alginate beads.

    PubMed

    Ben Hammouda, Samia; Adhoum, Nafaâ; Monser, Lotfi

    2016-01-15

    Iron-alginate beads (Fe-ABs) were successfully prepared by the ion-gelation method, and applied as heterogeneous Fenton catalysts for the removal of a malodorous compound 'indole'. Similarly, copper-enriched alginate beads (Cu-ABs) were synthesized and tested as like-Fenton catalyst, however, their application proved not to be effective for this purpose. Fe-ABs catalysts were characterized by FTIR, SEM, EDS and AAS spectroscopy. Results pointed out that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimal conditions, complete indole removal and considerably high reduction of TOC, without significant leaching was achieved. Indole decay followed a pseudo-first-order kinetics. The absolute rate constant for indole hydroxylation was 3.59×10(9) M(-1) s(-1), as determined by the competition kinetics method. Four reaction intermediates (Isatin, Dioxindole, Oxindole and Anthralinic acid) were identified by ULC/MS/MS analysis. Short-chain aliphatic carboxylic acids like formic, acetic, oxalic, maleic, oxamic and pyruvic acids were identified by ion exclusion chromatography and as end-products. Based on the identified by-products, a plausible mineralization pathway was proposed. Moreover, the catalyst was recovered quantitatively by simple filtration and reused for several times without significant loss of activity. PMID:26384996

  1. 3 dimensional cell cultures: a comparison between manually and automatically produced alginate beads.

    PubMed

    Lehmann, R; Gallert, C; Roddelkopf, T; Junginger, S; Wree, A; Thurow, K

    2016-08-01

    Cancer diseases are a common problem of the population caused by age and increased harmful environmental influences. Herein, new therapeutic strategies and compound screenings are necessary. The regular 2D cultivation has to be replaced by three dimensional cell culturing (3D) for better simulation of in vivo conditions. The 3D cultivation with alginate matrix is an appropriate method for encapsulate cells to form cancer constructs. The automated manufacturing of alginate beads might be an ultimate method for large-scaled manufacturing constructs similar to cancer tissue. The aim of this study was the integration of full automated systems for the production, cultivation and screening of 3D cell cultures. We compared the automated methods with the regular manual processes. Furthermore, we investigated the influence of antibiotics on these 3D cell culture systems. The alginate beads were formed by automated and manual procedures. The automated steps were processes by the Biomek(®) Cell Workstation (celisca, Rostock, Germany). The proliferation and toxicity were manually and automatically evaluated at day 14 and 35 of cultivation. The results visualized an accumulation and expansion of cell aggregates over the period of incubation. However, the proliferation and toxicity were faintly and partly significantly decreased on day 35 compared to day 14. The comparison of the manual and automated methods displayed similar results. We conclude that the manual production process could be replaced by the automation. Using automation, 3D cell cultures can be produced in industrial scale and improve the drug development and screening to treat serious illnesses like cancer.

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

    PubMed

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

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

  3. Biodegradation of wastewater pollutants by activated sludge encapsulated inside calcium-alginate beads in a tubular packed bed reactor.

    PubMed

    Sergio, A Martinez D; Bustos, T Yaneth

    2009-09-01

    The wastewater treatment plants produce large quantities of biomass (sludge) that require about one-third of the total inversion and operation plant costs for their treatment. By the microorganisms immobilization it is possible to handle high cell concentration in the reactor, increasing its efficiency, reducing the loss of biomass and the wash out is avoided. Moreover, there is no cell growth then the sludge production is reduced. In this study, the COD removal and VSS variation were modeled in a tubular reactor with activated sludge immobilized in Ca-alginate. Moreover, two aspects that are commonly not considered in the performance of the actual reactors of this kind were introduced; the performance in non-steady state and the dispersion effect. The model was calibrated with an actual wastewater taken out from a Mexican wastewater treatment plant. The results of the performance of the tubular bioreactor at different scenarios (i.e., different residence time and VSS in the reactor) are presented. With longer residence times and higher VSS concentration in the Ca-alginate beads in the tubular bioreactor it is possible to increase the time operation of the bioreactor and to treat higher volumes of wastewater. During the process, the sludge generation was drastically reduced and it is possible to remove nitrogen form the wastewater making this process more attractive.

  4. Calcium alginate beads encapsulated PMMA-g-CS nano-particles for α-chymotrypsin immobilization.

    PubMed

    Abd El-Ghaffar, M A; Hashem, M S

    2013-02-15

    Chitosan grafted with polymethyl methacrylate (PMMA-g-CS) was prepared via a free-radicals polymerization technique as a carrier for enzyme immobilization. α-Chymotrypsin (CT), as an enzyme model in this study, was immobilized onto the prepared PMMA-g-CS via covalent bonding. Calcium alginate (CA) beads were developed for encapsulating PMMA-g-CS-CT to produce PMMA-g-CS-CT/CA composite beads. Morphology and size of PMMA-g-CS particles were investigated by TEM and found to be in the nanoscale. The structure and surface morphology of the beads before and after immobilization process were characterized by FT-IR and SEM, respectively. Both the bound CT content and relative activity of immobilized enzyme were measured. A higher retained activity (about 97.7%) obtained for the immobilized CT at pH 9 for 24 h. The results indicated that immobilized CT maintained excellent performance even after 25 reuses and retained 75% from its original activity after 60 days of storage at 25 °C.

  5. Development, optimization and in vitro-in vivo evaluation of pioglitazone- loaded jackfruit seed starch-alginate beads.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Hasnain, Saquib Md

    2013-10-01

    The present investigation describes development and optimization of pioglitazone-loaded jackfruit seed starch (JFSS)-alginate beads by ionotropic-gelation using 3(2) factorial design. The effect of polymer-blend ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release after 10 hours (R10h, %) was optimized. The DEE (%) of these beads were 64.80 ± 1.92 to 94.07 ± 3.82 % with sustained in vitro drug release of 64.± 1.83 to 92.66 ± 4.54 % over 10 hours. The in vitro drug release from these beads followed controlled-release pattern with super case-II transport. Particle size range of these beads was 0.77 ± 0.04 to 1.24 ± 0.09 mm. The beads were also characterized by SEM and FTIR. The swelling of these beads was influenced by pH of the test medium. The optimized pioglitazone-loaded JFSS-alginate beads showed significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration.

  6. Alginate beads as a carrier for omeprazole/SBA-15 inclusion compound: A step towards the development of personalized paediatric dosage forms.

    PubMed

    Del Gaudio, Pasquale; De Cicco, Felicetta; Sansone, Francesca; Aquino, Rita Patrizia; Adami, Renata; Ricci, Maurizio; Giovagnoli, Stefano

    2015-11-20

    The treatment of gastro-esophageal reflux disease (GERD) shows several issues among paediatric patients. This work aims to the formulation of enteric alginate beads loaded with omeprazole (OME) allowing age- and weight-related personalized dosages in children. OME was entrapped in SBA-15 mesoporous compound, characterized and loaded into alginate beads by prilling at different OME and alginate concentrations. The beads resulted of homogeneous size, spherical morphology and very consistent in drug loading and distribution. Formulations demonstrated limited swelling and release (about 10%) in simulated gastric fluid (SGF) after 2h and a prolonged release in simulated intestinal fluid (SIF), till 6h, due to a mixed diffusion-case II transport mechanism. The beads were superior to the market product, which showed lower release in SGF but immediate dissolution in SIF. The high alginate beads uniformity and release properties make them a potential novel tool for a personalized treatment of GERD in children. PMID:26344303

  7. Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: preparation, swelling behavior, and drug delivery.

    PubMed

    Mahdavinia, Gholam Reza; Rahmani, Zeinab; Karami, Shiva; Pourjavadi, Ali

    2014-01-01

    This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K(+)/Ca(2+) ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending on the composition of hydrogel beads and the type of metal cations in swelling media. The swelling ratio of beads indicated pH-dependent properties with maximum water absorbing at pH 7.4. Also, it was found that the strength of pH-sensitivity of magnetic beads was low for beads with the high content of carrageenan component. The in vitro drug release studies from hydrogels exhibited significant behaviors on the subject of physiological-simulated pH values and external magnetic fields. The maximum cumulative releases obtained were 98 and 43% at pH values 7.4 and 1.2, respectively. The Introducing magnetite nanoparticles influenced the cumulative release of drug. PMID:25197770

  8. Ultrasound-assisted dextranase entrapment onto Ca-alginate gel beads.

    PubMed

    Bashari, Mohanad; Wang, Pei; Eibaid, Ahmed; Tian, Yaoqi; Xu, Xueming; Jin, Zhengyu

    2013-07-01

    In this research work, dextranase has immobilized onto calcium alginate beads using a novel ultrasound method. The process of immobilization of the enzyme was carried out in a one-step ultrasound process. Effects of ultrasound conditions on loading efficiency and immobilization yield of the enzyme onto calcium alginate beads were investigated. Furthermore, the activity of the free and immobilized enzymes prepared with and without ultrasound treatment, as a function of pH, temperature, recyclability and enzyme kinetic parameters, was compared. The maximum loading efficiency and the immobilization yield were observed when the immobilized dextranase was prepared with an ultrasonic irradiation at 25 kHz, 40 W for 15 min, under which the loading efficiency and the immobilization yield increased by 27.21% and 18.77%, respectively, compared with the immobilized enzymes prepared without ultrasonic irradiation. On the other hand, immobilized enzyme prepared with ultrasonic irradiation showed Vmax and KM value higher than that for the immobilized enzyme prepared without ultrasonic irradiation, likewise, both the catalytic and specificity constants of immobilized enzyme prepared with ultrasonic irradiation were higher than that for immobilized enzyme prepared without ultrasound, indicating that, this new ultrasonic method improved the catalytic kinetics activity of immobilized dextranase at all the reaction conditions studied. Compared with immobilized enzyme prepared without ultrasound treatment, the immobilized enzymes prepared with ultrasound irradiation exhibited: a higher pH optimum, optimal reaction temperature, activation energy, and thermal stability, as well as, a higher recyclability, which, illustrating the effectiveness of the sonochemical method. To the best of our knowledge, this is the first report on the effect of ultrasound treatments on the immobilization of dextranase.

  9. Calcium/Cobalt Alginate Beads as Functional Scaffolds for Cartilage Tissue Engineering

    PubMed Central

    Focaroli, Stefano; Teti, Gabriella; Salvatore, Viviana; Orienti, Isabella; Falconi, Mirella

    2016-01-01

    Articular cartilage is a highly organized tissue with complex biomechanical properties. However, injuries to the cartilage usually lead to numerous health concerns and often culminate in disabling symptoms, due to the poor intrinsic capacity of this tissue for self-healing. Although various approaches are proposed for the regeneration of cartilage, its repair still represents an enormous challenge for orthopedic surgeons. The field of tissue engineering currently offers some of the most promising strategies for cartilage restoration, in which assorted biomaterials and cell-based therapies are combined to develop new therapeutic regimens for tissue replacement. The current study describes the in vitro behavior of human adipose-derived mesenchymal stem cells (hADSCs) encapsulated within calcium/cobalt (Ca/Co) alginate beads. These novel chondrogenesis-promoting scaffolds take advantage of the synergy between the alginate matrix and Co+2 ions, without employing costly growth factors (e.g., transforming growth factor betas (TGF-βs) or bone morphogenetic proteins (BMPs)) to direct hADSC differentiation into cartilage-producing chondrocytes. PMID:27057167

  10. Adsorption studies of cadmium ions on alginate-calcium carbonate composite beads

    NASA Astrophysics Data System (ADS)

    Mahmood, Zahid; Amin, Athar; Zafar, Uzma; Raza, Muhammad Amir; Hafeez, Irfan; Akram, Adnan

    2015-07-01

    Alginate-calcium carbonate composite material was prepared in the form of beads and characterized using Fourier transform infra red (FT-IR) spectroscopy and scanning electron microscope (SEM) techniques. The adsorption of Cd2+ ions was studied through batch experiments. The adsorption parameters such as contact time (120 min), adsorbent dose (1.5 g), initial metal ion concentration(10 mg/L), pH (6) and agitation speed (150 rpm) were optimized at room temperature. Langmuir and Freundlich isotherms were applied to the data and it was noted that the adsorption of Cd2+ ions is better explained by Freundlich model. The kinetic studies showed that the adsorption of Cd2+ ions followed pseudo-first order kinetics. Thermodynamic parameters like ∆G 0, ∆H 0 and ∆S 0 were calculated and on the basis of these values it was established that the adsorption process is feasible and endothermic in nature. It was concluded from the study that the composite material of alginate and calcium carbonate can effectively be used to recover Cd2+ ions from wastewater.

  11. Formulation and stability evaluation of 3D alginate beads potentially useful for cumulus-oocyte complexes culture.

    PubMed

    Dorati, Rossella; Genta, Ida; Ferrari, Michela; Vigone, Giulia; Merico, Valeria; Garagna, Silvia; Zuccotti, Maurizio; Conti, Bice

    2016-01-01

    Ovarian follicle encapsulation in synthetic or natural matrixes based on biopolymers is potentially a promising approach to in vitro maturation (IVM) process, since it maintains follicle 3D organisation by preventing its flattening and consequent disruption of gap junctions, preserving the functional relationship between oocyte and companion follicle cells. The aim of the work was to optimise physico-chemical parameters of alginate microcapsules for perspective IVM under 3D environments. On this purpose alginate and cross-linking agent concentrations were investigated. Alginate concentration between 0.75% and 0.125% w/w and Mg(2+), Ba(2+), Ca(2+ )at concentration between 100 and 20 mM were tested. Follicle encapsulation was obtained by on purpose modified diffusion setting gelation technique, and evaluated together with beads, chemical and mechanical stability in standard and stressing conditions. Beads permeability was tested towards albumin, fetuin, pyruvate, glucose, pullulan. Results demonstrated that 0.25% alginate cross-linked in 100 mM CaCl2 beads is suitable to follicle encapsulation. PMID:26791322

  12. The smaller, the better? The size effect of alginate beads carrying plant growth-promoting bacteria for seed coating.

    PubMed

    Berninger, Teresa; Mitter, Birgit; Preininger, Claudia

    2016-01-01

    A range of lab-scale methods for encapsulation of plant growth-promoting bacteria in alginate beads intended for seed coating was evaluated: contact-spotting, extrusion through syringe with/without vibration, ejection by robotic liquid handler, extrusion by centrifugal force and commercial devices (nanodispenser, aerodynamically assisted jetting, encapsulator). Two methods were selected based on throughput (encapsulator: 1.5-5 mL/min; syringe with subsequent pulverisation: 5 mL/min). Four bead sizes (55 ± 39 μm, 104 ± 23 μm, 188 ± 16 μm and 336 ± 20 μm after lyophilisation) were produced. Bacterial viability, release, bead morphology, seed surface coverage and attrition were investigated. Release from the smallest bead size was approximately 10 times higher than from the largest. Seed surface coverage was highest (69 ± 3%) when alginate beads produced with nozzle size 80 μm were applied. Pulverised macro-beads are an alternative option, if high throughput is top priority. PMID:26791103

  13. Removal of ofloxacin antibiotic using heterogeneous Fenton process over modified alginate beads.

    PubMed

    Titouhi, Hana; Belgaied, Jamel-Eddine

    2016-07-01

    The aim of this work is to study the heterogeneous oxidative degradation of ofloxacin antibiotic using a composite material prepared from sodium alginate and cyclohexane dinitrilo tetraacetic acid (CDTA). The characterization tests indicated the successful incorporation of metal chelator and iron. It was also demonstrated that the synthesized beads are mesoporous. The influence of several experimental parameters (i.e.: H2O2 dose, working temperature, beads loading and initial drug concentration) on the process performances was evaluated. The reaction temperature significantly affects the drug conversion efficiency. It was also observed that the synthesized material was efficient toward the target antibiotic degradation in the presence of small quantities of hydrogen peroxide. Under optimum conditions (0.05 g of granules, initial drug concentration=10mg/L, 25μL of 10mmol/L H2O2), conducted in a batch reaction, 94% degradation of ofloxacin was reached. The results also indicate that the composite material showed a reasonable stability; a relatively low decrease of activity after four successive runs (only 9%) and a negligible iron leaching (0.8%) have been observed. The synthesized composite material offered interesting advantages in terms of simplicity, good stability, ease of recovery from the liquid medium after use and its efficiency in the presence of low quantities of oxidant. It constitutes a good candidate in the water treatment area.

  14. Degradation of trichloroethylene (TCE) by nanoscale zero-valent iron (nZVI) immobilized in alginate bead.

    PubMed

    Kim, Hojeong; Hong, Hye-Jin; Jung, Juri; Kim, Seong-Hye; Yang, Ji-Won

    2010-04-15

    Nowadays, many researchers have studied the environmental application of the nanoscale zero-valent iron (nZVI) and several field applications for the groundwater remediation have been reported. Still, there are many concerns on the fate and transport of the nZVI and the corresponding risks. To avoid such concerns, it was investigated to immobilize nZVI in a support and then it was applied to degrade trichloroethylene (TCE). The nZVI and palladium-doped nZVI (Fe(0)- and Fe/Pd-alginate) were immobilized in the alginate bead where ferric and barium ions are used as the cross-linking cations of the bead. According to TEM (transmission electron microscopy), the size of the immobilized ZVI was as small as a few nanometers. From the surface analysis of the Fe/Pd-alginate, it is found that the immobilized nZVI has the core-shell structure. The core is composed of single crystal Fe(0), while most of irons on the surface are oxidized to Fe(3+). When 50 g/L of Fe/Pd-alginate (3.7 g Fe/L) was introduced to the aqueous solution, >99.8% of TCE was removed and the release of metal from the support was <3% of the loaded iron. The removal of TCE by Fe/Pd-alginate followed pseudo-first-order kinetics. The observed pseudo-first-order reaction constant (k(obs)) of Fe/Pd-alginate was 6.11 h(-1) and the mass normalized rate constant (k(m)) was 1.6 L h(-1) g(-1). The k(m) is the same order of magnitude with that of iron nanoparticles. In conclusion, it is considered that Fe/Pd-alginate can be used efficiently in the treatment of chlorinated solvent.

  15. Continuous fixed bed adsorption of Cu(II) by halloysite nanotube-alginate hybrid beads: an experimental and modelling study.

    PubMed

    Wang, Yanyan; Zhang, Xiang; Wang, Qiuru; Zhang, Bing; Liu, Jindun

    2014-01-01

    We used natural resources of halloysite nanotubes and alginate to prepare a novel porous adsorption material of organic-inorganic hybrid beads. The adsorption behaviour of Cu(II) onto the hybrid beads was examined by a continuous fixed bed column adsorption experiment. Meanwhile, the factors affecting the adsorption capacity such as bed height, influent concentration and flow rate were investigated. The adsorption capacity (Q0) reached 74.13 mg/g when the initial inlet concentration was 100 mg/L with a bed height of 12 cm and flow rate of 3 ml/min. The Thomas model and bed-depth service time fitted well with the experimental data. In the regeneration experiment, the hybrid beads retained high adsorption capacity after three adsorption-desorption cycles. Over the whole study, the new hybrid beads showed excellent adsorption and regeneration properties as well as favourable stability. PMID:25051464

  16. Influence of immobilization parameters on growth and lactic acid production by Streptococcus thermophilus and Lactobacillus bulgaricus co-immobilized in calcium alginate gel beads.

    PubMed

    Garbayo, I; Vílchez, C; Vega, J M; Nava-Saucedo, J E; Barbotin, J N

    2004-12-01

    Streptococcus thermophilus and Lactobacillus bulgaricus were co-immobilized in different systems with varying calcium (0.1-1.5 M) and alginate (1-2%, w/v) concentrations. Highest lactic acid production was 35 g l(-1) when both bacteria were in high viscosity beads (1%, w/v alginate) hardened in 0.1 M CaCl2 . The gel bead composition affected size and distribution of entrapped lactic acid bacteria.

  17. Magnetic hydrogel beads based on PVA/sodium alginate/laponite RD and studying their BSA adsorption.

    PubMed

    Mahdavinia, Gholam Reza; Mousanezhad, Sedigheh; Hosseinzadeh, Hamed; Darvishi, Farshad; Sabzi, Mohammad

    2016-08-20

    In this study double physically crosslinked magnetic hydrogel beads were developed by a simple method including solution mixing of sodium alginate and poly(vinyl alcohol) (PVA) containing magnetic laponite RD (Rapid Dispersion). Sodium alginate and PVA were physically crosslinked by Ca(2+) and freezing-thawing cycles, respectively. Magnetic laponite RD nanoparticles were incorporated into the system to create magnetic response and strengthen the hydrogels. All hybrids double physically crosslinked hydrogel beads were stable under different pH values without any disintegration. Furthermore, adsorption of bovine serum albumin (BSA) on the hydrogel beads was investigated on the subject of pH, ion strength, initial BSA concentration, and temperature. Nanocomposite beads exhibited maximum adsorption capacity for BSA at pH=4.5. The experimental adsorption isotherm data were well followed Langmuir model and based on this model the maximum adsorption capacity was obtained 127.3mgg(-1) at 308K. Thermodynamic parameters revealed spontaneous and monolayer adsorption of BSA on magnetic nanocomposites beads.

  18. Prussian blue caged in alginate/calcium beads as adsorbents for removal of cesium ions from contaminated water.

    PubMed

    Vipin, Adavan Kiliyankil; Hu, Baiyang; Fugetsu, Bunshi

    2013-08-15

    Prussian blue encapsulated in alginate beads reinforced with highly dispersed carbon nanotubes were prepared for the safe removal of cesium ions from aqueous solutions. Equilibrium and kinetic studies were conducted using different models and the goodness of mathematical fitting of the experimental data on the adsorption isotherms was in the order Langmuir>Freundlich, and that of the kinetic models were in the order of pseudo second order>pseudo first order. Fixed bed adsorption column analysis indicated that the beads can be used for large scale treatment of cesium contaminated water.

  19. Microencapsulation of probiotics in hydrogel particles: enhancing Lactococcus lactis subsp. cremoris LM0230 viability using calcium alginate beads.

    PubMed

    Yeung, Timothy W; Arroyo-Maya, Izlia J; McClements, David J; Sela, David A

    2016-04-01

    Probiotics are beneficial microbes often added to food products to enhance the health and wellness of consumers. A major limitation to producing efficacious functional foods containing probiotic cells is their tendency to lose viability during storage and gastrointestinal transit. In this study, the impact of encapsulating probiotics within food-grade hydrogel particles to mitigate sensitivity to environmental stresses was examined. Confocal fluorescence microscopy confirmed that Lactococcus lactis were trapped within calcium alginate beads formed by dripping a probiotic-alginate mixture into a calcium solution. Encapsulation improved the viability of the probiotics during aerobic storage: after seven days, less than a two-log reduction was observed in encapsulated cells stored at room temperature, demonstrating that a high concentration of cells survived relative to non-encapsulated bacteria. These hydrogel beads may have applications for improving the stability and efficacy of probiotics in functional foods.

  20. Optimisation of decolourisation and degradation of Reactive Black 5 dye under electro-Fenton process using Fe alginate gel beads.

    PubMed

    Iglesias, O; Fernández de Dios, M A; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode.

  1. Optimisation of decolourisation and degradation of Reactive Black 5 dye under electro-Fenton process using Fe alginate gel beads.

    PubMed

    Iglesias, O; Fernández de Dios, M A; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode. PMID:22733554

  2. Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads

    PubMed Central

    Dashtdar, Havva; Selvaratnam, Lakshmi; Balaji Raghavendran, Hanumantharao; Suhaeb, Abdulrazzaq Mahmod; Ahmad, Tunku Sara

    2016-01-01

    Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis. PMID:26966647

  3. Degradation of synthetic pollutants in real wastewater using laccase encapsulated in core-shell magnetic copper alginate beads.

    PubMed

    Le, Thao Thanh; Murugesan, Kumarasamy; Lee, Chung-Seop; Vu, Chi Huong; Chang, Yoon-Seok; Jeon, Jong-Rok

    2016-09-01

    Immobilization of laccase has been highlighted to enhance their stability and reusability in bioremediation. In this study, we provide a novel immobilization technique that is very suitable to real wastewater treatment. A perfect core-shell system composing copper alginate for the immobilization of laccase (Lac-beads) was produced. Additionally, nFe2O3 was incorporated for the bead recycling through magnetic force. The beads were proven to immobilize 85.5% of total laccase treated and also to be structurally stable in water, acetate buffer, and real wastewater. To test the Lac-beads reactivity, triclosan (TCS) and Remazol Brilliant Blue R (RBBR) were employed. The Lac-beads showed a high percentage of TCS removal (89.6%) after 8h and RBBR decolonization at a range from 54.2% to 75.8% after 4h. Remarkably, the pollutants removal efficacy of the Lac-beads was significantly maintained in real wastewater with the bead recyclability, whereas that of the corresponding free laccase was severely deteriorated. PMID:27240236

  4. Development of pH-sensitive tamarind seed polysaccharide-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar

    2011-11-01

    The present study deals with the development of novel pH-sensitive tamarind seed polysaccharide (TSP)-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology by full 3(2) factorial design. The effect of polymer-blend ratio (sodium alginate:TSP) and cross-linker (CaCl(2)) concentration on the drug encapsulation efficiency (DEE, %) and drug release from diclofenac sodium loaded TSP-alginate composite beads prepared by ionotropic gelation was optimized. The observed responses were coincided well with the predicted values by the experimental design. The DEE (%) of these beads containing diclofenac sodium was within the range between 72.23±2.14 and 97.32±4.03% with sustained in vitro drug release (69.08±2.36-96.07±3.54% in 10 h). The in vitro drug release from TSP-alginate composite beads containing diclofenac sodium was followed by controlled-release pattern (zero-order kinetics) with case-II transport mechanism. Particle size range of these beads was 0.71±0.03-1.33±0.04 mm. The swelling and degradation of the developed beads were influenced by different pH of the test medium. The FTIR and NMR analyses confirmed the compatibility of the diclofenac sodium with TSP and sodium alginate used to prepare the diclofenac sodium loaded TSP-alginate composite beads. The newly developed TSP-alginate composite beads are suitable for controlled delivery of diclofenac sodium for prolonged period.

  5. Development of pH-sensitive tamarind seed polysaccharide-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar

    2011-11-01

    The present study deals with the development of novel pH-sensitive tamarind seed polysaccharide (TSP)-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology by full 3(2) factorial design. The effect of polymer-blend ratio (sodium alginate:TSP) and cross-linker (CaCl(2)) concentration on the drug encapsulation efficiency (DEE, %) and drug release from diclofenac sodium loaded TSP-alginate composite beads prepared by ionotropic gelation was optimized. The observed responses were coincided well with the predicted values by the experimental design. The DEE (%) of these beads containing diclofenac sodium was within the range between 72.23±2.14 and 97.32±4.03% with sustained in vitro drug release (69.08±2.36-96.07±3.54% in 10 h). The in vitro drug release from TSP-alginate composite beads containing diclofenac sodium was followed by controlled-release pattern (zero-order kinetics) with case-II transport mechanism. Particle size range of these beads was 0.71±0.03-1.33±0.04 mm. The swelling and degradation of the developed beads were influenced by different pH of the test medium. The FTIR and NMR analyses confirmed the compatibility of the diclofenac sodium with TSP and sodium alginate used to prepare the diclofenac sodium loaded TSP-alginate composite beads. The newly developed TSP-alginate composite beads are suitable for controlled delivery of diclofenac sodium for prolonged period. PMID:21816168

  6. Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability.

    PubMed

    Gao, Hui; Khera, Eshita; Lee, Jung-Kul; Wen, Fei

    2016-04-22

    We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst immobilization for improved production yield and sustained synthesis. Described herewith is the experimental procedure for the development of such a system consisting of two E. coli strains that express functionally complementary enzymes. Together, these two enzymes can function co-operatively to mediate the regeneration of expensive cofactors for improving the product yield of the bioreaction. In addition, the method of synthesizing an immobilized form of the coupled biocatalytic system by encapsulation of whole cells in calcium alginate beads is reported. As an example, we present the improved biosynthesis of L-xylulose from L-arabinitol by coupling E. coli cells expressing the enzymes L-arabinitol dehydrogenase or NADH oxidase. Under optimal conditions and using an initial concentration of 150 mM L-arabinitol, the maximal L-xylulose yield reached 96%, which is higher than those reported in the literature. The immobilized form of the coupled whole-cell biocatalysts demonstrated good operational stability, maintaining 65% of the yield obtained in the first cycle after 7 cycles of successive re-use, while the free cell system almost completely lost the catalytic activity. Therefore, the methods reported here provides two strategies that could help improve the industrial production of L-xylulose, as well as other value-added compounds requiring the use of cofactors in general.

  7. High pressure studies on hesperitin production with hesperidinase free and immobilized in calcium alginate beads

    NASA Astrophysics Data System (ADS)

    Furtado, Andreia; Rosário, Pedro M.; Calado, António R. T.; Alfaia, António J. I.; Ribeiro, Maria H. L.

    2012-03-01

    The use of high pressure for the enzymatic synthesis of pharmacologically interesting molecules is a very important tool. Hesperidin and hesperitin exhibit anti-inflammatory, antimicrobial, antioxidant, and anticarcinogenic properties and prevent bone loss. However, hesperidin has a low bioavailability compared with hesperitin, due to the rutinoside moiety attached to the flavonoid. The aim of this work was the enzymatic production of hesperitin from hesperidin (soluble and insoluble) with hesperidinase free and immobilized in Ca-alginate beads, under high pressure conditions. The work was focused on the optimization of enzyme activity, studying the effects: pressure (50-150 MPa), temperature (35-75 °C), concentration of substrate (100-800 mg/L), and immobilization of hesperidinase. An 18-fold increase in hesperidinase residual activity was observed under high pressure conditions of 100 MPa compared to 0.1 MPa. A higher specificity of the hydrolytic reaction under high pressure (100 MPa) with a two-and three-fold increase in the ratio K cat/K M (specificity constant) at 55 °C and 75 °C was observed. A two-fold increase in the maximum activity at 100 MPa was observed with immobilized hesperinase compared to 0.1 MPa. In the second reutilization, almost a four-fold increase was obtained under high pressure conditions in comparison to atmospheric pressure.

  8. Continuous flow adsorption of methylene blue by cellulose nanocrystal-alginate hydrogel beads in fixed bed columns.

    PubMed

    Mohammed, Nishil; Grishkewich, Nathan; Waeijen, Herman Ambrose; Berry, Richard M; Tam, Kam Chiu

    2016-01-20

    The adsorption behavior of methylene blue by cellulose nanocrystal-alginate (CNC-ALG) hydrogel beads in a fixed bed column was studied by varying the initial dye concentrations, bed depths and flow rates. An unusual phenomenon was observed in the early phase of the adsorption, and the phenomenon was elucidated by varying other critical design parameters, such as the flow direction, diameter of column and composition of adsorbent. The swelling and shrinkage of hydrogel beads during the adsorption was responsible for the anomalous concentration versus time profile of the adsorption process. The maximum adsorption capacity of the column was 255.5mg/g, which is in agreement with the batch study determined from the Langmuir adsorption isotherm. A comprehensive understanding on the adsorption mechanism of CNC-ALG hydrogel beads during the early stages of adsorption was derived from this study.

  9. Histomorphometric Evaluation of Cartilage Degradation using Rabbit Articular Chondrocytes Cultured in Alginate Beads − Effects of Hyaluronan

    PubMed Central

    Nakatsuka, K.; Kurita, K.; Hayakawa, Taro; Nakashima, Katsuhito; Yamashita, Kyoko; Hoshino, Takeshi; Miyazaki, Kyosuke

    2010-01-01

    Objective: A 3-dimensional alginate bead culturing method using rabbit articular chondrocytes was studied for the screening of the effectiveness of drugs for articular diseases. Design: The beads cultured with IL-1β, TGF-β, and Hyaluronan (HA) were evaluated histochemically with Alecian blue and immunohistochemically with CS-56 antibody. Chondrocytes in alginate beads were arbitrarily classified into four groups: 1) chodrocyte surrounded with cell-associated matrix (CAM) in which proteoglycan (PG) was positively stained (PG-possitive chondrocyte); 2) chondrocyte with PG-negative CAM; 3) PG-positive CAM alone, and 4) PG-negative CAM alone. Total sulfated GAG concentrations in the culture media were quantitated by dimethylmethylene blue (DMMB) assay. ProMMP-3, TIMP-1 and –2 concentrations in the culture media were determined by sandwich enzyme immunoassays. Results: Significant increase of PG-nagative cells were immunohistochemically found by IL-1β stimulation. The pretreatment with TGF-β almost fully suppressed those increase of PG-negative cells by IL-1β. Both GAG and proMMP-3 concentrations in the culture media were significantly increased after IL-1β stimulation. There were no significant differences in both TIMP-1 and TIMP-2 concentrations in the culture media with or without IL-1β stimulation. 800-kDa HA reduced significantly the number of PG-negative cells and proMMP-3 concentration in the culture media, but showed no effects on the concentrations of both TIMPs. Conclusions: Because this 3-dimensional chondrocyte culture in alginate beads is close to in vivo conditions, this method can be used for evaluation of the effectiveness of novel drugs for articular diseases. PMID:23675183

  10. Affinity covalent immobilization of glucoamylase onto ρ-benzoquinone-activated alginate beads: II. Enzyme immobilization and characterization.

    PubMed

    Eldin, M S Mohy; Seuror, E I; Nasr, M A; Tieama, H A

    2011-05-01

    A novel affinity covalent immobilization technique of glucoamylase enzyme onto ρ-benzoquinone-activated alginate beads was presented and compared with traditional entrapment one. Factors affecting the immobilization process such as enzyme concentration, alginate concentration, calcium chloride concentration, cross-linking time, and temperature were studied. No shift in the optimum temperature and pH of immobilized enzymes was observed. In addition, K (m) values of free and entrapped glucoamylase were found to be almost identical, while the covalently immobilized enzyme shows the lowest affinity for substrate. In accordance, V (m) value of covalently immobilized enzyme was found lowest among free and immobilized counter parts. On the other hand, the retained activity of covalently immobilized glucoamylase has been improved and was found higher than that of entrapped one. Finally, the industrial applicability of covalently immobilized glucoamylase has been investigated through monitoring both shelf and operational stability characters. The covalently immobilized enzyme kept its activity over 36 days of shelf storage and after 30 repeated use runs. Drying the catalytic beads greatly reduced its activity in the beginning but recovered its lost part during use. In general, the newly developed affinity covalent immobilization technique of glucoamylase onto ρ-benzoquinone-activated alginate carrier is simple yet effective and could be used for the immobilization of some other enzymes especially amylases.

  11. Immobilization of tomato (Lycopersicon esculentum) pectinmethylesterase in calcium alginate beads and its application in fruit juice clarification.

    PubMed

    Bogra, Pushpa; Kumar, Ashwani; Kuhar, Kalika; Panwar, Surbhi; Singh, Randhir

    2013-11-01

    Clarity of fruit juices is desirable to maintain an aesthetically pleasing quality and international standards. The most commonly used enzymes in juice industries are pectinases. A partially-purified pectinmethylesterase from tomato was entrapped in calcium alginate beads and used for juice clarification. The activity yield was maximum at 1 % (w/v) CaCl2 and 2.5 % (w/v) alginate. The immobilized enzyme retained ~55 % of its initial activity (5.7 × 10(-2) units) after more than ten successive batch reactions. The Km, pH and temperature optima were increased after immobilization. The most effective clarification of fruit juice (%T620 ~60 %) by the immobilized enzyme was at 4 °C with a holding time of 20 min. The viscosity dropped by 56 % and the filterability increased by 260 %. The juice remains clear after 2 months of storage at 4 °C.

  12. Increased Growth of the Microalga Chlorella vulgaris when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense†

    PubMed Central

    Gonzalez, Luz E.; Bashan, Yoav

    2000-01-01

    Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments. PMID:10742237

  13. Enhancement of osteoblastic differentiation in alginate gel beads with bioactive octacalcium phosphate particles.

    PubMed

    Endo, Kosei; Anada, Takahisa; Yamada, Masumi; Seki, Minoru; Sasaki, Keiichi; Suzuki, Osamu

    2015-12-01

    The present study investigated whether alginate (Alg) hydrogel microbeads have a role in maintaining mouse bone marrow stromal ST-2 cells and release the cells after being stimulated by synthetic octacalcium phosphate (OCP), which is a mineral crystal capable of stimulating osteoblastic differentiation during a conversion process to hydroxyapatite (HA). The ST-2 cell suspension in the alginate solution, which contained various concentrations of OCP granules with diameters less than 53 μm, was extruded drop-wise into a stirred gelation solution containing BaCl2 using an encapsulator with nitrogen gas stream. The Alg-microbeads (Alg/OCP · ST-2 microbeads) that were generated, which had a diameter of approximately 400 μm, were incubated for up to 14 d and then assessed for osteoblastic differentiation. Alg-microbeads with cells were also incubated to identify the possible conversion from OCP to HA. Osteoblast differentiation markers in ST-2 cells, alkaline phosphatase (ALP) and collagen type I, were up-regulated in the presence of higher amounts of OCP. X-ray diffraction analysis and Fourier transform infrared spectroscopy confirmed that the OCP tended to convert to HA over time, suggesting that the OCP in Alg-microbeads interacts three-dimensionally with ST-2 cells and stimulates its osteoblastic differentiation. The release of ST-2 cells from the microbeads was also estimated. ST-2 cells were identified outside of the microbeads, although the cell number tended to decrease with increasing OCP. These results suggest that Alg/OCP microbeads could be used as a vehicle to activate osteoblastic cells and deliver them to sites where bone regeneration is needed. PMID:26657659

  14. Impact of alginate composition: from bead mechanical properties to encapsulated HepG2/C3A cell activities for in vivo implantation.

    PubMed

    Capone, Stephanie H; Dufresne, Murielle; Rechel, Mathias; Fleury, Marie-José; Salsac, Anne-Virginie; Paullier, Patrick; Daujat-Chavanieu, Martine; Legallais, Cecile

    2013-01-01

    Recently, interest has focused on hepatocytes' implantation to provide end stage liver failure patients with a temporary support until spontaneous recovery or a suitable donor becomes available. To avoid cell damage and use of an immunosuppressive treatment, hepatic cells could be implanted after encapsulation in a porous biomaterial of bead or capsule shape. The aim of this study was to compare the production and the physical properties of the beads, together with some hepatic cell functions, resulting from the use of different material combinations for cell microencapsulation: alginate alone or combined with type I collagen with or without poly-L-lysine and alginate coatings. Collagen and poly-L-lysine increased the bead mechanical resistance but lowered the mass transfer kinetics of vitamin B12. Proliferation of encapsulated HepG2/C3A cells was shown to be improved in alginate-collagen beads. Finally, when the beads were subcutaneously implanted in mice, the inflammatory response was reduced in the case of alginate mixed with collagen. This in vitro and in vivo study clearly outlines, based on a systematic comparison, the necessity of compromising between material physical properties (mechanical stability and porosity) and cell behavior (viability, proliferation, functionalities) to define optima hepatic cell microencapsulation conditions before implantation.

  15. Impact of Alginate Composition: From Bead Mechanical Properties to Encapsulated HepG2/C3A Cell Activities for In Vivo Implantation

    PubMed Central

    Capone, Stephanie H.; Dufresne, Murielle; Rechel, Mathias; Fleury, Marie-José; Salsac, Anne-Virginie; Paullier, Patrick; Daujat-Chavanieu, Martine; Legallais, Cecile

    2013-01-01

    Recently, interest has focused on hepatocytes’ implantation to provide end stage liver failure patients with a temporary support until spontaneous recovery or a suitable donor becomes available. To avoid cell damage and use of an immunosuppressive treatment, hepatic cells could be implanted after encapsulation in a porous biomaterial of bead or capsule shape. The aim of this study was to compare the production and the physical properties of the beads, together with some hepatic cell functions, resulting from the use of different material combinations for cell microencapsulation: alginate alone or combined with type I collagen with or without poly-L-lysine and alginate coatings. Collagen and poly-L-lysine increased the bead mechanical resistance but lowered the mass transfer kinetics of vitamin B12. Proliferation of encapsulated HepG2/C3A cells was shown to be improved in alginate-collagen beads. Finally, when the beads were subcutaneously implanted in mice, the inflammatory response was reduced in the case of alginate mixed with collagen. This in vitro and in vivo study clearly outlines, based on a systematic comparison, the necessity of compromising between material physical properties (mechanical stability and porosity) and cell behavior (viability, proliferation, functionalities) to define optima hepatic cell microencapsulation conditions before implantation. PMID:23637958

  16. Thermodynamic, Kinetic, and Equilibrium Parameters for the Removal of Lead and Cadmium from Aqueous Solutions with Calcium Alginate Beads

    PubMed Central

    Alfaro-Cuevas-Villanueva, Ruth; Hidalgo-Vázquez, Aura Roxana; Cortés Penagos, Consuelo de Jesús; Cortés-Martínez, Raúl

    2014-01-01

    The sorption of cadmium (Cd) and lead (Pb) by calcium alginate beads (CAB) from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K2) for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F) and Dubinin-Radushkevich (D-R) models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7. PMID:24587740

  17. Efficient Pb(II) removal using sodium alginate-carboxymethyl cellulose gel beads: Preparation, characterization, and adsorption mechanism.

    PubMed

    Ren, Huixue; Gao, Zhimin; Wu, Daoji; Jiang, Jiahui; Sun, Youmin; Luo, Congwei

    2016-02-10

    Alginate-carboxymethyl cellulose (CMC) gel beads were prepared in this study using sodium alginate (SA) and sodium CMC through blending and cross-linking. The specific surface area and aperture of the prepared SA-CMC gel beads were tested. The SA-CMC structure was characterized and analyzed via infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Static adsorption experiment demonstrated that Pb(II) adsorption of SA-CMC exceeded 99% under the optimized conditions. In addition, experiments conducted under the same experimental conditions showed that the lead ion removal efficiency of SA-CMC was significantly higher than that of conventional adsorbents. The Pb(II) adsorption process of SA-CMC followed the Langmuir adsorption isotherm, and the dynamic adsorption model could be described through a pseudo-second-order rate equation. Pb(II) removal mechanisms of SA-CMC, including physical, chemical, and electrostatic adsorptions, were discussed based on microstructure analysis and adsorption kinetics. Chemical adsorption was the main adsorption method among these mechanisms. PMID:26686144

  18. Modeling studies: Adsorption of aniline blue by using Prosopis Juliflora carbon/Ca/alginate polymer composite beads.

    PubMed

    Kumar, M; Tamilarasan, R

    2013-02-15

    The research article describes the experimental and modeling study for the adsorptive removal of aniline blue dye (AB dye) from aqueous matrices using a Prosopis Juliflora modified carbon/Ca/alginate polymer bead as a low cost and eco-friendly adsorbent. The rate of adsorption was investigated under various experimental parameters such as contact time, adsorbent dose, dye concentration, pH and temperature. The kinetics, equilibrium and thermodynamic studies were assessed to find out the efficiency of the adsorption process. The equilibrium uptake capacity of the adsorption process was found with Freundlich and Langmuir adsorption isotherm equations and it was evaluated by dimensionless separation factor (R(L)). The dynamics of adsorption was predicted by pseudo-first order, pseudo-second order Lagergren's equation and intra particle diffusion model. Adsorption feasibility was assessed with thermodynamic parameters such as isosteric heat of adsorption (ΔH°), standard entropy (ΔS°) and Gibbs free energy (ΔG°) using VantHoff plot. The alginate bead was characterized with FTIR spectroscopy and Scanning Electron Microscopy (SEM).

  19. Fe(0)-Fe3O4 nanocomposites embedded polyvinyl alcohol/sodium alginate beads for chromium (VI) removal.

    PubMed

    Lv, Xiaoshu; Jiang, Guangming; Xue, Xiaoqin; Wu, Donglei; Sheng, Tiantian; Sun, Chen; Xu, Xinhua

    2013-11-15

    In this study, Fe(0)-Fe3O4 nanocomposites embedded polyvinyl alcohol (PVA)/sodium alginate (SA) beads were synthesized, which exhibited an excellent physical properties and catalytic reactivity, and a robust performance of post-separation (complete separation using a simple grille) and reusability (efficiency of 69.8% after four runs) in Cr(VI) removal. 5.0 wt% PVA with 1.5 wt% SA was the optimal proportion for beads molding, and the followed acidification and reduction treatments were critical to ensure high mechanical strength and high Cr(VI) removal ability of beads. Effects of Fe(0) and Fe3O4 mass fraction, initial pH and Cr(VI) concentration on final removal efficiency were also evaluated. Merely 0.075 wt% Fe(0) together with 0.30 wt% Fe3O4 was sufficient to deal with 20 mg L(-1) Cr(VI) solution. The efficiency decreased from 100 to 79.5% as initial Cr(VI) increased from 5 to 40 mg L(-1), while from 99.3 to 76.3% with increasing pH from 3.0 to 11.0. This work provides a practical and high-efficient method for heavy metal removal from water body, and simultaneously solves the problems in stabilization, separation and regeneration of Fe(0) nanoparticles.

  20. Chitosan coated alginate-xanthan gum bead enhanced pH and thermotolerance of Lactobacillus plantarum LAB12.

    PubMed

    Fareez, Ismail M; Lim, Siong Meng; Mishra, Rakesh K; Ramasamy, Kalavathy

    2015-01-01

    The vulnerability of probiotics at low pH and high temperature has limited their optimal use as nutraceuticals. This study addressed these issues by adopting a physicochemical driven approach of incorporating Lactobacillus plantarum LAB12 into chitosan (Ch) coated alginate-xanthan gum (Alg-XG) beads. Characterisation of Alg-XG-Ch, which elicited little effect on bead size and polydispersity, demonstrated good miscibility with improved bead surface smoothness and L. plantarum LAB12 entrapment when compared to Alg, Alg-Ch and Alg-XG. Sequential incubation of Alg-XG-Ch in simulated gastric juice and intestinal fluid yielded high survival rate of L. plantarum LAB12 (95%) at pH 1.8 which in turn facilitated sufficient release of probiotics (>7 log CFU/g) at pH 6.8 in both time- and pH-dependent manner. Whilst minimising viability loss at 75 and 90 °C, Alg-XG-Ch improved storage durability of L. plantarum LAB12 at 4 °C. The present results implied the possible use of L. plantarum LAB12 incorporated in Alg-XG-Ch as new functional food ingredient with health claims.

  1. Enhanced degradation of phenol by Pseudomonas sp. CP4 entrapped in agar and calcium alginate beads in batch and continuous processes.

    PubMed

    Aneez Ahamad, P Y; Mohammad Kunhi, A A

    2011-04-01

    Phenol is one of the major toxic pollutants in the wastes generated by a number of industries and needs to be eliminated before their discharge. Although microbial degradation is a preferred method of waste treatment for phenol removal, the general inability of the degrading strains to tolerate higher substrate concentrations has been a bottleneck. Immobilization of the microorganism in suitable matrices has been shown to circumvent this problem to some extent. In this study, cells of Pseudomonas sp. CP4, a laboratory isolate that degrades phenol, cresols, and other aromatics, were immobilized by entrapment in Ca-alginate and agar gel beads, separately and their performance in a fluidized bed bioreactor was compared. In batch runs, with an aeration rate of 1 vol(-1) vol(-1) min(-1), at 30°C and pH 7.0 ± 0.2, agar-encapsulated cells degraded up to 3000 mg l(-1) of phenol as compared to 1500 mg l(-1) by Ca-alginate-entrapped cells whereas free cells could tolerate only 1000 mg l(-1). In a continuous process with Ca-alginate entrapped cells a degradation rate of 200 mg phenol l(-1) h(-1) was obtained while agar-entrapped cells were far superior and could withstand and degrade up to 4000 mg phenol l(-1) in the feed with a maximum degradation rate of 400 mg phenol l(-1) h(-1). The results indicate a clear possibility of development of an efficient treatment technology for phenol containing waste waters with the agar-entrapped bacterial strain, Pseudomonas sp. CP4.

  2. Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker.

    PubMed

    Sinha, Priyanka; Ubaidulla, U; Hasnain, M Saquib; Nayak, Amit Kumar; Rama, Bobba

    2015-08-01

    Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery.

  3. Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker.

    PubMed

    Sinha, Priyanka; Ubaidulla, U; Hasnain, M Saquib; Nayak, Amit Kumar; Rama, Bobba

    2015-08-01

    Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery. PMID:25987461

  4. Plantago ovata F. Mucilage-Alginate Mucoadhesive Beads for Controlled Release of Glibenclamide: Development, Optimization, and In Vitro-In Vivo Evaluation.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2013-01-01

    The current study deals with the development and optimization of ispaghula (Plantago ovata F.) husk mucilage- (IHM-) alginate mucoadhesive beads containing glibenclamide by ionotropic gelation technique. The effects of sodium alginate (SA) to IHM and cross-linker (CaCl2) concentration on the drug encapsulation efficiency (DEE, %), as well as cumulative drug release after 10 hours (R10 h, %), were optimized using 3(2) factorial design based on response surface methodology. The observed responses were coincided well with the predicted values by the experimental design. The optimized mucoadhesive beads exhibited 94.43 ± 4.80% w/w of DEE and good mucoadhesivity with the biological membrane in wash-off test and sustained drug release profile over 10 hours. The beads were also characterized by SEM and FTIR analyses. The in vitro drug release from these beads was followed by controlled release (zero-order) pattern with super case-II transport mechanism. The optimized glibenclamide-loaded IHM-alginate mucoadhesive beads showed significant antidiabetic effect in alloxan-induced diabetic rats over prolonged period after oral administration. PMID:26555967

  5. Efficiency of barium removal from radioactive waste water using the combination of maghemite and titania nanoparticles in PVA and alginate beads.

    PubMed

    Majidnia, Zohreh; Idris, Ani; Majid, MuhdZaimiAbd; Zin, RosliMohamad; Ponraj, Mohanadoss

    2015-11-01

    In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA-alginate beads fitted the pseudo first order and second order Langmuir-Hinshelwood (L-H) kinetic model.

  6. Efficiency of barium removal from radioactive waste water using the combination of maghemite and titania nanoparticles in PVA and alginate beads.

    PubMed

    Majidnia, Zohreh; Idris, Ani; Majid, MuhdZaimiAbd; Zin, RosliMohamad; Ponraj, Mohanadoss

    2015-11-01

    In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA-alginate beads fitted the pseudo first order and second order Langmuir-Hinshelwood (L-H) kinetic model. PMID:26275818

  7. Influence of a cationic surfactant on adsorption of p-nitrophenol by a magsorbent based on magnetic alginate beads.

    PubMed

    Obeid, Layaly; El Kolli, Nadia; Talbot, Delphine; Welschbillig, Mathias; Bée, Agnès

    2015-11-01

    The paper focuses on the removal of p-nitrophenol by an adsorption process. A magnetic adsorbent was synthesized by encapsulation of magnetic functionalized nanoparticles using alginate as a green biopolymer matrix. A cationic surfactant, cetylpyridinium chloride (CPyCl), was used to confer a hydrophobic character to the magnetic beads and thus to promote their adsorption efficiency. The effect of different parameters such as initial concentrations of both PNP and CPyCl, contact time and solution pH value on the adsorption of PNP in the presence of CPyCl was investigated. It should be noted that combination of magnetic and adsorption properties in a same material is an interesting challenge which could overcome the recovery problems of pollutant-loaded adsorbent. PMID:26188728

  8. Suppression of leaf feeding and oviposition of phytophagous ladybird beetles (Coleoptera: Coccinellidae) by chitinase gene-transformed phylloplane bacteria and their specific bacteriophages entrapped in alginate gel beads.

    PubMed

    Otsu, Yasunari; Mori, Hirofumi; Komuta, Kenji; Shimizu, Hiroyuki; Nogawa, Souta; Matsuda, Yoshinori; Nonomura, Teruo; Sakuratani, Yasuyuki; Tosa, Yukio; Mayama, Shigeyuki; Toyoda, Hideyoshi

    2003-06-01

    The chitinase gene-transformed strain KPM-007E/chi of Enterobacter cloacae was vitally entrapped in sodium alginate gel beads with its specific virulent bacteriophage EcP-01 to provide a new method for microbially digesting chitinous peritrophic membranes of phytophagous ladybird beetles Epilachna vigintioctopunctata. First, chitinase SH1 from a gram-positive bacterium Kurthia zopfii was overproduced by Escherichia coli cells and purified by affinity column chromatography. The purified enzyme effectively digested peritrophic membranes dissected from the ladybird beetles to expose epithelial tissues beneath the peritrophic membrane, and the beetles that had ingested chitinase after submergence in chitinase solution had considerably reduced their feeding on tomato leaves. KPM-007E/chi, entrapped in the alginate beads, released the chitinase. More chitinase was released when KPM-007E/chi was present with their specific virulent bacteriophage EcP-01 in the beads because of lysis of bacterial cells infected with the bacteriophages. This chitinase release from the microbial beads (containing KPM-007E/chi and EcP-01) was sufficient to digest the peritrophic membrane as well as to suppress feeding of bead-sprayed tomato leaves by the ladybird beetles. A daily supply of tomato leaves treated with the microbial beads considerably suppressed leaf feeding and oviposition by the ladybird beetles, suggesting a possible application of chitinase-secreting bacteria for suppressing herbivorous insect pests.

  9. 3D Dynamic Culture of Rabbit Articular Chondrocytes Encapsulated in Alginate Gel Beads Using Spinner Flasks for Cartilage Tissue Regeneration

    PubMed Central

    Xu, Feiyue; Xu, Lei; Wang, Qi; Ye, Zhaoyang; Zhou, Yan; Tan, Wen-Song

    2014-01-01

    Cell-based therapy using chondrocytes for cartilage repair suffers from chondrocyte dedifferentiation. In the present study, the effects of an integrated three-dimensional and dynamic culture on rabbit articular chondrocytes were investigated. Cells (passages 1 and 4) were encapsulated in alginate gel beads and cultured in spinner flasks in chondrogenic and chondrocyte growth media. Subcutaneous implantation of the cell-laden beads was performed to evaluate the ectopic chondrogenesis. It was found that cells remained viable after 35 days in the three-dimensional dynamic culture. Passage 1 cells demonstrated a proliferative growth in both media. Passage 4 cells showed a gradual reduction in DNA content in growth medium, which was attenuated in chondrogenic medium. Deposition of glycosaminoglycans (GAG) was found in all cultures. While passage 1 cells generally produced higher amounts of GAG than passage 4 cells, GAG/DNA became similar on day 35 for both cells in growth media. Interestingly, GAG/DNA in growth medium was greater than that in chondrogenic medium for both cells. Based on GAG quantification and gene expression analysis, encapsulated passage 1 cells cultured in growth medium displayed the best ectopic chondrogenesis. Taken together, the three-dimensional and dynamic culture for chondrocytes holds great potential in cartilage regeneration. PMID:25506593

  10. Monodisperse alginate microgel formation in a three-dimensional microfluidic droplet generator

    SciTech Connect

    Lian, Meng; Collier, C. Patrick; Doktycz, Mitchel J.; Retterer, Scott T.

    2012-12-01

    Droplet based microfluidic systems provide an ideal platform for partitioning and manipulating aqueous samples for analysis. Identifying stable operating conditions under which droplets are generated is challenging yet crucial for real-world applications. A novel three-dimensional microfluidic platform that facilitates the consistent generation and gelation of alginate-calcium hydrogel microbeads for microbial encapsulation, over a broad range of backing pressures, in the absence of surfactants, is described. The unique three-dimensional design of the fluidic network utilizes a height difference at the junction between the aqueous sample injection and organic carrier channels to induce droplet formation via a surface tension enhanced self-shearing mechanism. Combined within a flow-focusing geometry, under constant pressure control, this arrangement facilitates predictable generation of droplets over a much broader range of operating conditions than conventional two-dimensional systems. The impact of operating pressures and geometry on droplet gelation, aqueous and organic material flow rates, microbead size and bead generation frequency are described. The system presented provides a robust platform for encapsulating single microbes in complex mixtures into individual hydrogel beads, and provides the foundation for the development of a complete system for sorting and analyzing microbes at the single cell level.

  11. Isolation of Inositol Hexaphosphate (IHP)-Degrading Bacteria from Arbuscular Mycorrhizal Fungal Hyphal Compartments Using a Modified Baiting Method Involving Alginate Beads Containing IHP

    PubMed Central

    Hara, Shintaro; Saito, Masanori

    2016-01-01

    Phytate (inositol hexaphosphate; IHP)-degrading microbes have been suggested to contribute to arbuscular mycorrhizal fungi (AMF)-mediated P transfer from IHP to plants; however, no IHP degrader involved in AMF-mediated P transfer has been isolated to date. We herein report the isolation of IHP-degrading bacteria using a modified baiting method. We applied alginate beads as carriers of IHP powder, and used them as recoverable IHP in the AM fungal compartment of plant cultivation experiments. P transfer from IHP in alginate beads via AMF was confirmed, and extracted DNA from alginate beads was analyzed by denaturing gradient gel electrophoresis targeting the 16S rRNA gene and a clone library method for the beta-propeller phytase (BPP) gene. The diversities of the 16S rRNA and BPP genes of microbes growing on IHP beads were simple and those of Sphingomonas spp. and Caulobacter spp. dominated. A total of 187 IHP-utilizing bacteria were isolated and identified, and they were consistent with the results of DNA analysis. Furthermore, some isolated Sphingomonas spp. and Caulobacter sp. showed IHP-degrading activity. Therefore, we successfully isolated dominant IHP-degrading bacteria from IHP in an AMF hyphal compartment. These strains may contribute to P transfer from IHP via AMF. PMID:27383681

  12. Hydroxyapatite-doped alginate beads as scaffolds for the osteoblastic differentiation of mesenchymal stem cells.

    PubMed

    Wang, Martha O; Bracaglia, Laura; Thompson, Joshua A; Fisher, John P

    2016-09-01

    This work investigates the role of an osteoblastic matrix component, hydroxyapatite (HA), in modular alginate scaffolds to support osteoblastic differentiation of human mesenchymal stem cells for the purpose of tissue engineered bone constructs. This system is first evaluated in a tubular perfusion bioreactor, which has been shown to improve osteoblastic differentiation over static culture conditions. HMSCs in alginate scaffolds that contain HA show increased osteoblastic gene expression compared to cells in pure alginate scaffolds, as well as significantly more matrix production and mineralization. The differentiated hMSCs and cell-laid matrix are ultimately evaluated in an in vivo site specific model. Implantation of these scaffolds with preformed matrix into the rat femoral condyle defects results in abundant bone growth and significant incorporation of the scaffold into the surrounding tissue. The developed mineralized matrix, induced in part by the HA component in the scaffold, could lead to increased tissue development in critically sized defects, and should be included in future implant strategies. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2325-2333, 2016.

  13. Biodegradation of tetrahydrofuran by Pseudomonas oleovorans DT4 immobilized in calcium alginate beads impregnated with activated carbon fiber: mass transfer effect and continuous treatment.

    PubMed

    Chen, Dong-Zhi; Fang, Jun-Yi; Shao, Qian; Ye, Jie-Xu; Ouyang, Du-Juan; Chen, Jian-Meng

    2013-07-01

    A novel entrapment matrix, calcium alginate (CA) coupled with activated carbon fiber (ACF), was prepared to immobilize Pseudomonas oleovorans DT4 for degrading tetrahydrofuran (THF). The addition of 1.5% ACF increased the adsorption capacity of the immobilized bead, thus resulting in an enhanced average removal rate of 30.3mg/(Lh). The synergism between adsorption and biodegradation was observed in the hybrid CA-ACF beads instead of in the system comprising CA beads and freely suspended ACF. The effective diffusion coefficient of the CA-ACF bead was not significantly affected by bead size, but the bead's value of 1.14×10(-6)cm(2)/s (for the bead diameter of 0.4 cm) was larger than that of the CA bead by almost one order of magnitude based on the intraparticle diffusion-reaction kinetics analysis. Continuous treatment of the THF-containing wastewater was succeeded by CA-ACF immobilized cells in a packed-bed reactor for 54 d with a >90% removal efficiency. PMID:23644074

  14. Biodegradation of tetrahydrofuran by Pseudomonas oleovorans DT4 immobilized in calcium alginate beads impregnated with activated carbon fiber: mass transfer effect and continuous treatment.

    PubMed

    Chen, Dong-Zhi; Fang, Jun-Yi; Shao, Qian; Ye, Jie-Xu; Ouyang, Du-Juan; Chen, Jian-Meng

    2013-07-01

    A novel entrapment matrix, calcium alginate (CA) coupled with activated carbon fiber (ACF), was prepared to immobilize Pseudomonas oleovorans DT4 for degrading tetrahydrofuran (THF). The addition of 1.5% ACF increased the adsorption capacity of the immobilized bead, thus resulting in an enhanced average removal rate of 30.3mg/(Lh). The synergism between adsorption and biodegradation was observed in the hybrid CA-ACF beads instead of in the system comprising CA beads and freely suspended ACF. The effective diffusion coefficient of the CA-ACF bead was not significantly affected by bead size, but the bead's value of 1.14×10(-6)cm(2)/s (for the bead diameter of 0.4 cm) was larger than that of the CA bead by almost one order of magnitude based on the intraparticle diffusion-reaction kinetics analysis. Continuous treatment of the THF-containing wastewater was succeeded by CA-ACF immobilized cells in a packed-bed reactor for 54 d with a >90% removal efficiency.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  17. Modified alginate and chitosan for lactic acid bacteria immobilization.

    PubMed

    Le-Tien, Canh; Millette, Mathieu; Mateescu, Mircea-Alexandru; Lacroix, Monique

    2004-06-01

    Beads with enhanced-stability acid media, which were based on alginate and chitosan functionalized by succinylation (increasing the anionic charges able to retain protons) or by acylation (improving matrix hydrophobicity), were developed for immobilization of bacterial cells. Beads (3 mm diameter) formed by ionotropic gelation with CaCl(2) presented good mechanical characteristics. After 30 min incubation of viable free Lactobacillus rhamnosus cells in simulated gastric fluid (pH 1.5), we noticed that the level of viable bacteria was undetectable. Bacterial immobilization in native-alginate-based beads generated a viable-cell count of 22-26%, whereas, when entrapped in succinylated alginate and chitosan beads, the percentage of viable cells was of 60 and 66%, respectively. Best viability (87%) was found for bacteria immobilized in N -palmitoylaminoethyl alginate, which affords a high protective effect, probably due to long alkyl pendants that improve the beads' hydrophobicity, limiting hydration in the acidic environment.

  18. Characterization of structure, physico-chemical properties and diffusion behavior of Ca-Alginate gel beads prepared by different gelation methods.

    PubMed

    Puguan, John Marc C; Yu, Xiaohong; Kim, Hern

    2014-10-15

    Ca-Alginate beads were prepared with either external or internal calcium sources by dripping technique. It was found that beads synthesized with internal calcium source had a looser structure and bigger pore size than those produced with external calcium source. Consequently, a faster diffusion rate of Vitamin B12 (VB12) within the beads with an internal calcium source was observed. Furthermore, the concentration of calcium ion, ionic strength and pH of the external gel beads formation solution were investigated. Results showed that (a) the concentration of the calcium ion was found to be the determining factor in the gel formation phenomenon; (b) the weight and volume losses are in effect due to water removal; (c) NaCl acts as a competitor with calcium and a screen in the electrostatic repulsion; and (d) the pH controls the gel formation process by regulating the dissociation of alginate and the complexation of the calcium cations. These results are keys to understanding the behavior and performance of beads in their utilization medium.

  19. Removal of mercury (II) from aqueous solution using papain immobilized on alginate bead: optimization of immobilization condition and modeling of removal study.

    PubMed

    Bhattacharyya, Aparupa; Dutta, Susmita; De, Parameswar; Ray, Parthasarathi; Basu, Srabanti

    2010-12-01

    Papain having the characteristics of metal binding ability is immobilized on alginate bead. Design Expert Software (Version 7.1.6) uses Response Surface Methodology (RSM) for statistical designing of operating condition for immobilization of papain on alginate bead considering concentration of papain, concentration of sodium alginate, concentration of calcium chloride and pH as numeric factors and Specific Enzymatic Activity (SEA) of immobilized papain sample as response. Immobilization using 25.96 g/L papain, 20 g/L sodium alginate and 20 g/L calcium chloride at pH 7 gives the desired product as indicated by ANOVA (Analysis of Variance). Three parameters viz., initial concentration of mercury (II), amount of AIP and pH are varied in a systematic manner. Maximum 98.88% removal of mercury (II) has been achieved within 8 min when simulated aqueous solution of mercury (II) with initial concentration of 10mg/L has been contacted with 5 g of AIP at pH 9 and at 35 degrees C in a batch contactor. A mathematical model has been developed and the value of equilibrium constant for binding of mercury (II) with AIP has been found to be 126797.3. PMID:20696575

  20. Removal of mercury (II) from aqueous solution using papain immobilized on alginate bead: optimization of immobilization condition and modeling of removal study.

    PubMed

    Bhattacharyya, Aparupa; Dutta, Susmita; De, Parameswar; Ray, Parthasarathi; Basu, Srabanti

    2010-12-01

    Papain having the characteristics of metal binding ability is immobilized on alginate bead. Design Expert Software (Version 7.1.6) uses Response Surface Methodology (RSM) for statistical designing of operating condition for immobilization of papain on alginate bead considering concentration of papain, concentration of sodium alginate, concentration of calcium chloride and pH as numeric factors and Specific Enzymatic Activity (SEA) of immobilized papain sample as response. Immobilization using 25.96 g/L papain, 20 g/L sodium alginate and 20 g/L calcium chloride at pH 7 gives the desired product as indicated by ANOVA (Analysis of Variance). Three parameters viz., initial concentration of mercury (II), amount of AIP and pH are varied in a systematic manner. Maximum 98.88% removal of mercury (II) has been achieved within 8 min when simulated aqueous solution of mercury (II) with initial concentration of 10mg/L has been contacted with 5 g of AIP at pH 9 and at 35 degrees C in a batch contactor. A mathematical model has been developed and the value of equilibrium constant for binding of mercury (II) with AIP has been found to be 126797.3.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  3. Decolorization of textile effluent by bitter gourd peroxidase immobilized on concanavalin A layered calcium alginate-starch beads.

    PubMed

    Matto, Mahreen; Husain, Qayyum

    2009-05-30

    Bitter gourd peroxidase immobilized on the surface of concanavalin A layered calcium alginate-starch beads was used for the successful and effective decolorization of textile industrial effluent. Effluent was recalcitrant to the action of bitter gourd peroxidase; however, in the presence of some redox mediators, it was successfully decolorized. Effluent decolorization was maximum (70%) in the presence of 1.0mM 1-hydroxybenzotriazole within 1h of incubation. However, immobilized bitter gourd peroxidase showed maximum decolorization at pH 5.0 and 40 degrees C. Immobilized bitter gourd peroxidase decolorized more than 90% effluent after 3h of incubation in a batch process. The two-reactor system, one reactor containing immobilized peroxidase and the other had activated silica, was quite effective in the decolorization of textile effluent. The system was capable of decolorizing 40% effluent even after 2 months of continuous operation. The absorption spectra of the untreated and treated effluent exhibited a marked difference in absorbance at various wavelengths. Immobilized peroxidase/1-hydroxybenzotriazole system could be employed for the treatment of a large volume of effluent in a continuous reactor.

  4. Evaluation of propidium monoazide real-time PCR for enumeration of probiotic lactobacilli microencapsulated in calcium alginate beads.

    PubMed

    Oketič, K; Matijašić, B Bogovič; Obermajer, T; Radulović, Z; Lević, S; Mirković, N; Nedović, V

    2015-01-01

    The aim of the study was to evaluate real-time PCR coupled with propidium monoazide (PMA) treatment for enumeration of microencapsulated probiotic lactobacilli microencapsulated in calcium alginate beads. Lactobacillus gasseri K7 (CCM 7710) and Lactobacillus delbrueckii subsp. bulgaricus (CCM 7712) were analysed by plate counting and PMA real-time PCR during storage at 4 °C for 90 days. PMA was effective in preventing PCR amplification of the target sequences of DNA released from heat-compromised bacteria. The values obtained by real-time PCR of non-treated samples were in general higher than those obtained by real-time PCR of PMA-treated samples or by plate counting, indicating the presence of sub-lethally injured cells. This study shows that plate count could not be completely replaced by culture independent method PMA real-time PCR for enumeration of probiotics, but may rather complement the well-established plate counting, providing useful information about the ratio of compromised bacteria in the samples.

  5. Production, partial characterization, and immobilization in alginate beads of an alkaline protease from a new thermophilic fungus Myceliophthora sp.

    PubMed

    Zanphorlin, Letícia Maria; Facchini, Fernanda Dell Antonio; Vasconcelos, Filipe; Bonugli-Santos, Rafaella Costa; Rodrigues, André; Sette, Lara Durães; Gomes, Eleni; Bonilla-Rodriguez, Gustavo Orlando

    2010-06-01

    Thermophilic fungi produce thermostable enzymes which have a number of applications, mainly in biotechnological processes. In this work, we describe the characterization of a protease produced in solidstate (SSF) and submerged (SmF) fermentations by a newly isolated thermophilic fungus identified as a putative new species in the genus Myceliophthora. Enzyme-production rate was evaluated for both fermentation processes, and in SSF, using a medium composed of a mixture of wheat bran and casein, the proteolytic output was 4.5-fold larger than that obtained in SmF. Additionally, the peak of proteolytic activity was obtained after 3 days for SSF whereas for SmF it was after 4 days. The crude enzyme obtained by both SSF and SmF displayed similar optimum temperature at 50 degrees C, but the optimum pH shifted from 7 (SmF) to 9(SSF). The alkaline protease produced through solid-state fermentation (SSF), was immobilized on beads of calcium alginate, allowing comparative analyses of free and immobilized proteases to be carried out. It was observed that both optimum temperature and thermal stability of the immobilized enzyme were higher than for the free enzyme. Moreover, the immobilized enzyme showed considerable stability for up to 7 reuses.

  6. Rapid degradation of phenanthrene by using Sphingomonas sp. GY2B immobilized in calcium alginate gel beads.

    PubMed

    Tao, Xue-Qin; Lu, Gui-Ning; Liu, Jie-Ping; Li, Ting; Yang, Li-Ni

    2009-09-01

    The strain Sphingomonas sp. GY2B is a high efficient phenanthrene-degrading strain isolated from crude oil contaminated soils that displays a broad-spectrum degradation ability towards PAHs and related aromatic compounds. This paper reports embedding immobilization of strain GY2B in calcium alginate gel beads and the rapid degradation of phenanthrene by the embedded strains. Results showed that embedded immobilized strains had high degradation percentages both in mineral salts medium (MSM) and 80% artificial seawater (AS) media, and had higher phenanthrene degradation efficiency than the free strains. More than 90% phenanthrene (100 mg x L(-1)) was degraded within 36 h, and the phenanthrene degradation percentages were >99.8% after 72 h for immobilized strains. 80% AS had significant negative effect on the phenanthrene degradation rate (PDR) of strain GY2B during the linear-decreasing stage of incubation and preadsorption of cells onto rice straw could improve the PDR of embedded strain GY2B. The immobilization of strain GY2B possesses a good potential for application in the treatment of industrial wastewater containing phenanthrene and other related aromatic compounds.

  7. Batch and continuous flow studies of adsorptive removal of Cr(VI) by adapted bacterial consortia immobilized in alginate beads.

    PubMed

    Samuel, Jastin; Pulimi, Mrudula; Paul, Madona L; Maurya, Arun; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2013-01-01

    The adsorptive removal of Cr(VI) by alginate beads containing Cr(VI)-adapted Acinetobacter junii, Escherichia coli and Bacillus subtilis in batch and continuous packed bed column reactors was investigated. Under optimized conditions (pH 3.0; contact time, 180 min; 30 °C; initial Cr(VI) concentration of 100 mg/L), 65.86 mg/g adsorption capacity was recorded in the batch study. When an adsorbent dosage of 1g/L, a flow rate of 5 mL/min, a bed height of 20 cm, an initial Cr(VI) concentration of 300 mg/L was employed, a capacity of 657 mg/g was noted for the continuous column assay. The batch sorption data followed the Langmuir isotherm and pseudo second order kinetics. Five sorption/desorption cycles yielded 100%, 99.63%, 95.31%, 80.7% and 74.22% regeneration, respectively. Cr(VI) adsorption studies using spiked ground water, freshwater and domestic wastewater in a packed bed reactor demonstrated Cr(VI) removals of 64.8%, 55.08%, 56.86% respectively. Cr(VI) sorption on immobilized bacteria was confirmed with Fourier-transform infrared and Energy dispersive X-ray spectroscopy. PMID:23201524

  8. Improving of catalase stability properties by encapsulation in alginate/Fe3O4 magnetic composite beads for enzymatic removal of H2O2.

    PubMed

    Doğaç, Yasemin Ispirli; Çinar, Mürvet; Teke, Mustafa

    2015-01-01

    The aim of this study was enhancing of stability properties of catalase enzyme by encapsulation in alginate/nanomagnetic beads. Amounts of carrier (10-100 mg) and enzyme concentrations (0.25-1.5 mg/mL) were analyzed to optimize immobilization conditions. Also, the optimum temperature (25-50°C), optimum pH (3.0-8.0), kinetic parameters, thermal stability (20-70°C), pH stability (4.0-9.0) operational stability (0-390 min), and reusability were investigated for characterization of the immobilized catalase system. The optimum pH levels of both free and immobilized catalase were 7.0. At the thermal stability studies, the magnetic catalase beads protected 90% activity, while free catalase maintained only 10% activity at 70°C. The thermal profile of magnetic catalase beads was spread over a large area. Similarly, this system indicated the improving of the pH stability. The reusability, which is especially important for industrial applications, was also determined. Thus, the activity analysis was done 50 times in succession. Catalase encapsulated magnetic alginate beads protected 83% activity after 50 cycles.

  9. Retention and release of oil-in-water emulsions from filled hydrogel beads composed of calcium alginate: impact of emulsifier type and pH.

    PubMed

    Zeeb, Benjamin; Saberi, Amir Hossein; Weiss, Jochen; McClements, David Julian

    2015-03-21

    Delivery systems based on filled hydrogel particles (microgels) can be fabricated from natural food-grade lipids and biopolymers. The potential for controlling release characteristics by modulating the electrostatic interactions between emulsifier-coated lipid droplets and the biopolymer matrix within hydrogel particles was investigated. A multistage procedure was used to fabricate calcium alginate beads filled with lipid droplets stabilized by non-ionic, cationic, anionic, or zwitterionic emulsifiers. Oil-in-water emulsions stabilized by Tween 60, DTAB, SDS, or whey protein were prepared by microfluidization, mixed with various alginate solutions, and then microgels were formed by simple extrusion into calcium solutions. The microgels were placed into a series of buffer solutions with different pH values (2 to 11). Lipid droplets remained encapsulated under acidic and neutral conditions, but were released under highly basic conditions (pH 11) due to hydrogel swelling when the alginate concentration was sufficiently high. Lipid droplet release increased with decreasing alginate concentration, which could be attributed to an increase in the pore size of the hydrogel matrix. These results have important implications for the design of delivery systems to entrap and control the release of lipophilic bioactive components within filled hydrogel particles. PMID:25646949

  10. Calcium alginate bead immobilization of cells containing tyrosine ammonia lyase activity for use in the production of p-hydroxycinnamic acid.

    PubMed

    Trotman, Robert J; Camp, Carl E; Ben-Bassat, Arie; DiCosimo, Robert; Huang, Lixuan; Crum, Grace A; Sariaslani, F Sima; Haynie, Sharon L

    2007-01-01

    An Escherichia coli catalyst with tyrosine ammonia lyase activity (TAL) has been stabilized for repeated use in batch conversions of high tyrosine solids to p-hydroxycinnamic acid (pHCA). The TAL biocatalyst was stabilized by controlling the reaction pH to 9.8 +/- 0.1 and immobilizing the cells within a calcium alginate matrix that was cross-linked with glutaraldehyde and polyethyleneimine (GA/PEI). We found a GA range where the bead-encapsulated TAL was not inactivated, and the resulting cross-linking provided the beads with the mechanical stability necessary for repeated use in consecutive batch reactions with catalyst recycle. The GA/PEI calcium alginate TAL catalyst was used in 41 1-L batch reactions where 50 g L(-1) tyrosine was converted to 39 +/- 4 g L(-1) pHCA in each batch. The practical usefulness and ease of this process was demonstrated by scaling up the TAL bead immobilization and using the immobilized TAL catalyst in four 125-L bioconversion reactions to produce over 12 kg of purified pHCA.

  11. Fabrication and detection of tissue engineered bone aggregates based on encapsulated human ADSCs within hybrid calcium alginate/bone powder gel-beads in a spinner flask.

    PubMed

    Song, Kedong; Yang, Yanfei; Xu, Lili; Tian, Jiaxin; Fan, Jiangli; Jiao, Zeren; Feng, Shihao; Wang, Hong; Wang, Yiwei; Wang, Ling; Liu, Tianqing

    2016-05-01

    Traditional treatment for bone diseases limits their clinical application due to undesirable host immune rejection, limited donator sources and severe pain and suffering for patients. Bone tissue engineering therefore is expected to be a more effective way in treating bone diseases. In the present study, hybrid calcium alginate/bone powder gel-beads with a uniform size distribution, good biocompatibility and osteoinductive capability, were prepared to be used as an in-vitro niche-like matrix. The beads were optimized using 2.5% (w/v) sodium alginate solution, 4.5% (w/v) CaCl2 solution and 5.0mg/mL bone powder using an easy-to-use method. Human ADSCs were cultured and induced into chondrocytes and osteoblasts, respectively. The cells were characterized by histological staining showing the ADSCs were able to maintain their characteristic morphology with multipotent differentiation ability. ADSCs at density of 5 × 10(6)cells/mL were encapsulated into the gel-beads aiming to explore cell expansion under different conditions and the osteogenic induction of ADSCs was verified by specific staining. Results demonstrated that the encapsulated ADSCs expanded 5.6 folds in 10 days under dynamic condition via spinner flask, and were able to differentiate into osteoblasts (OBs) with extensive mineralized nodules forming the bone aggregates over 3 weeks postosteogenic induction. In summary, hybrid gel-beads encapsulating ADSCs are proved to be feasible as a new method to fabricate tissue engineered bone aggregation with potential to treat skeletal injury in the near future. PMID:26952485

  12. Enzymatic detection of mercuric ions in ground-water from vegetable wastes by immobilizing pumpkin (Cucumis melo) urease in calcium alginate beads.

    PubMed

    Prakash, Om; Talat, Mahe; Hasan, Syed Hadi; Pandey, Rajesh K

    2008-07-01

    Present report describes a quick and simple test based on enzyme inhibition for the detection of mercury in aqueous medium by urease immobilized in alginate beads. Urease was extracted from the discarded seeds of pumpkin (Cucumis melo) and was purified to apparent homogeneity (5.2-fold) by heat treatment at 48+/-0.1 degrees C and gel filtration through Sephadex G-200. The homogeneous enzyme preparation (Sp activity 353 U/mg protein, A(280)/A(260)=1.12) was immobilized in 3.5% alginate leading to 86% immobilization. Effect of mercuric ion on the activity of soluble as well as immobilized enzyme was investigated. Hg(2+) exhibited a concentration-dependent inhibition both in the presence and absence of the substrate. The alginate immobilized enzyme showed less inhibition. There was no leaching of the enzyme over a period of 15 days at 4 degrees C. The inhibition was non-competitive and the K(i) was found to be 1.26x10(-1)microM. Time-dependent interaction of urease with Hg(2+) exhibited a biphasic inhibition behavior in which approximately half of the initial activity was lost rapidly (within 10 min) and reminder in a slow phase. Binding of Hg(2+) with the enzyme was largely irreversible, as the activity could not be restored by dialysis. The significance of the observations is discussed.

  13. Microfluidic generation of hollow Ca-alginate microfibers.

    PubMed

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

    2016-07-01

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

  14. Microfluidic generation of hollow Ca-alginate microfibers.

    PubMed

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

    2016-07-01

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

  15. Combination of Controllably Released Platelet Rich Plasma Alginate Beads and Bone Morphogenic Protein-2 Gene-Modified Mesenchymal Stem Cells for Bone Regeneration

    PubMed Central

    Fernandes, Gabriela; Wang, Changdong; Yuan, Xue; Liu, Zunpeng; Dziak, Rosemary; Yang, Shuying

    2016-01-01

    Background Platelet rich plasma (PRP) consists of platelet derived growth factor (PDGF) and Transforming growth factor-beta (TGF-β) that increase cell proliferation of mesenchymal stem cells (MSCs), whereas, bone morphogenic Protein-2 (BMP2) promotes osteogenic differentiation of MSCs. However, the high degradation rate of fibrin leads to the dissociation of cytokines even before the process of bone regeneration has begun. Hence, for the first time, we studied the combined effect of sustained released PRP from alginate beads on BMP2 modified MSCs osteogenic differentiation in vitro and of sustained PRP alone on a fracture defect model ex vivo as well as its effect on the calvarial suture closure. Methods After optimizing the concentration of alginate for the microspheres, the osteogenic and mineralization effect of PRP and BMP2 in combinations on MSCs was studied. A self-setting alginate hydrogel carrying PRP was tested on a femur defect model ex-vivo. The effect of PRP was studied on the closure of the embryonic (E15) mouse calvaria sutures ex vivo. Results Increase of PRP concentration promoted cellular proliferation of MSCs. 2.5%–10% of PRP displayed gradually increased ALP activity on the cells in a dose dependent manner. Sustained release PRP and BMP2 demonstrated a significantly higher ALP and mineralization activity (p<0.05). The radiographs of alginate hydrogel with PRP treated bone demonstrated a nearly complete healing of the fracture and the histological sections of the embryonic calvaria revealed that PRP leads to suture fusion. Conclusions Sustained release of PRP along with BMP2 gene modified MSCs can significantly promote bone regeneration. PMID:26745613

  16. Factors influencing alginate gel biocompatibility.

    PubMed

    Tam, Susan K; Dusseault, Julie; Bilodeau, Stéphanie; Langlois, Geneviève; Hallé, Jean-Pierre; Yahia, L'Hocine

    2011-07-01

    Alginate remains the most popular polymer used for cell encapsulation, yet its biocompatibility is inconsistent. Two commercially available alginates were compared, one with 71% guluronate (HiG), and the other with 44% (IntG). Both alginates were purified, and their purities were verified. After 2 days in the peritoneal cavity of C57BL/6J mice, barium (Ba)-gel and calcium (Ca)-gel beads of IntG alginate were clean, while host cells were adhered to beads of HiG alginate. IntG gel beads, however, showed fragmentation in vivo while HiG gel beads stayed firm. The physicochemical properties of the sodium alginates and their gels were thoroughly characterized. The intrinsic viscosity of IntG alginate was 2.5-fold higher than that of HiG alginate, suggesting a greater molecular mass. X-ray photoelectron spectroscopy indicated that both alginates were similar in elemental composition, including low levels of counterions in all gels. The wettabilities of the alginates and gels were also identical, as measured by contact angles of water on dry films. Ba-gel beads of HiG alginate resisted swelling and degradation when immersed in water, much more than the other gel beads. These results suggest that the main factors contributing to the biocompatibility of gels of purified alginate are the mannuronate/guluronate content and/or intrinsic viscosity.

  17. Enhanced adsorption of cesium on PVA-alginate encapsulated Prussian blue-graphene oxide hydrogel beads in a fixed-bed column system.

    PubMed

    Jang, Jiseon; Lee, Dae Sung

    2016-10-01

    A continuous fixed-bed column study was performed using PVA-alginate encapsulated Prussian blue-graphene oxide (PB-GO) hydrogel beads as a novel adsorbent for the removal of cesium from aqueous solutions. The effects of different operating parameters, such as initial cesium concentration, pH, bed height, flow rate, and bead size, were investigated. The maximum adsorption capacity of the PB-GO hydrogel beads was 164.5mg/g at an initial cesium concentration of 5mM, bed height of 20cm, and flow rate of 0.83mL/min at pH 7. The Thomas, Adams-Bohart, and Yoon-Nelson models were applied to the experimental data to predict the breakthrough curves using non-linear regression. Although both the Thomas and Yoon-Nelson models showed good agreement with the experimental data, the Yoon-Nelson model was found to provide the best representation for cesium adsorption on the adsorbent, based on the χ(2) analysis. PMID:27372009

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

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

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

  19. Characteristics of biochar derived from marine macroalgae and fabrication of granular biochar by entrapment in calcium-alginate beads for phosphate removal from aqueous solution.

    PubMed

    Jung, Kyung-Won; Jeong, Tae-Un; Kang, Ho-Jeong; Ahn, Kyu-Hong

    2016-07-01

    In this work, granular biochar, Laminaria japonica-derived biochar (LB)-calcium alginate beads (LB-CAB), was successfully prepared by dropping a mixture of powder biochar and alginate solution into a calcium chloride solution for phosphate adsorption. Among different marine macroalgae derived biochars, LB exhibited the best performance, showing a phosphate removal rate of 97.02%, which was attributed to its high Ca/P and Mg/P ratios. With increasing pyrolysis temperature up to 600°C, the physicochemical properties of LB became suitable for adsorbing phosphate. Experimental results of kinetics and equilibrium isotherms at different temperatures (10-30°C) showed that the phosphate adsorption process is endothermic and is mainly controlled by external mass transfer and the intraparticle diffusion rate. The maximum adsorption capacity was found to be 157.7mgg(-1) at 30°C, as fitted by the Langmuir-Freundlich model, which is higher than capacities of other powder form of biochars.

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

    DOE PAGES

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

    2016-02-03

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

  1. Swirl Flow Bioreactor coupled with Cu-alginate beads: A system for the eradication of Coliform and Escherichia coli from biological effluents.

    PubMed

    Atkinson, Sov; Thomas, Simon F; Goddard, Paul; Bransgrove, Rachel M; Mason, Paul T; Oak, Ajeet; Bansode, Anand; Patankar, Rohit; Gleason, Zachary D; Sim, Marissa K; Whitesell, Andrew; Allen, Michael J

    2015-05-21

    It is estimated that approximately 1.1 billion people globally drink unsafe water. We previously reported both a novel copper-alginate bead, which quickly reduces pathogen loading in waste streams and the incorporation of these beads into a novel swirl flow bioreactor (SFB), of low capital and running costs and of simple construction from commercially available plumbing pipes and fittings. The purpose of the present study was to trial this system for pathogen reduction in waste streams from an operating Dewats system in Hinjewadi, Pune, India and in both simulated and real waste streams in Seattle, Washington, USA. The trials in India, showed a complete inactivation of coliforms in the discharged effluent (Mean Log removal Value (MLRV) = 3.51), accompanied by a total inactivation of E. coli with a MLRV of 1.95. The secondary clarifier effluent also showed a 4.38 MLRV in viable coliforms during treatment. However, the system was slightly less effective in reducing E. coli viability, with a MLRV of 1.80. The trials in Seattle also demonstrated the efficacy of the system in the reduction of viable bacteria, with a LRV of 5.67 observed of viable Raoultella terrigena cells (100%).

  2. Swirl Flow Bioreactor coupled with Cu-alginate beads: A system for the eradication of Coliform and Escherichia coli from biological effluents

    PubMed Central

    Atkinson, Sov; Thomas, Simon F.; Goddard, Paul; Bransgrove, Rachel M.; Mason, Paul T.; Oak, Ajeet; Bansode, Anand; Patankar, Rohit; Gleason, Zachary D.; Sim, Marissa K.; Whitesell, Andrew; Allen, Michael J.

    2015-01-01

    It is estimated that approximately 1.1 billion people globally drink unsafe water. We previously reported both a novel copper-alginate bead, which quickly reduces pathogen loading in waste streams and the incorporation of these beads into a novel swirl flow bioreactor (SFB), of low capital and running costs and of simple construction from commercially available plumbing pipes and fittings. The purpose of the present study was to trial this system for pathogen reduction in waste streams from an operating Dewats system in Hinjewadi, Pune, India and in both simulated and real waste streams in Seattle, Washington, USA. The trials in India, showed a complete inactivation of coliforms in the discharged effluent (Mean Log removal Value (MLRV) = 3.51), accompanied by a total inactivation of E. coli with a MLRV of 1.95. The secondary clarifier effluent also showed a 4.38 MLRV in viable coliforms during treatment. However, the system was slightly less effective in reducing E. coli viability, with a MLRV of 1.80. The trials in Seattle also demonstrated the efficacy of the system in the reduction of viable bacteria, with a LRV of 5.67 observed of viable Raoultella terrigena cells (100%). PMID:25999243

  3. Ripple structure-generated hybrid electrokinetics for on-chip mixing and separating of functionalized beads.

    PubMed

    Cheng, I-Fang; Chiang, Sheng-Chuan; Chung, Cheng-Che; Yeh, Trai-Ming; Chang, Hsien-Chang

    2014-11-01

    We present an electrokinetics-based microfluidic platform that is capable of on-chip manipulating, mixing, and separating microparticles through adjusting the interrelated magnitudes of dielectrophoresis and AC electroosmosis. Hybrid electrokinetic phenomenon is generated from an electric field-induced micro-ripple structure made of ultraviolet-curable glue. Size-dependent particle separation and selective removal over the ripple structure is demonstrated successfully. Varying the waveform from sine-wave to square-wave allows generating a fluid convection at specific positions to mix the antibody-functionalized beads and antigen. Potential application in the bead-based immunoassay was also demonstrated for immuno-reaction and subsequently separating the bead-bead aggregate and non-binding beads on-chip.

  4. Preparation and Evaluation of Mucoadhesive Beads/Discs of Alginate and Algino-Pectinate of Piroxicam for Colon-Specific Drug Delivery Via Oral Route

    PubMed Central

    Jelvehgari, Mitra; Mobaraki, Vajihe; Montazam, Seyed Hassan

    2014-01-01

    Background: Targeted drug delivery to colon would ensure direct treatment at the disease site, decrease in dose administration and reduction side effects improved drug utilization. Objective: The purpose of this research was to decrease gastric side effects of piroxicam by formulating microspheres of alginate and algino-pectinate beads of the drug. Materials and Methods: Ionotropic gelation was used to entrap piroxicam into alginate and algino-pectinate mucoadhesive microspheres as a potential drug carrier for oral delivery of piroxicam. Microparticles with different drug to polymers ratio were prepared and characterized by encapsulation efficiency, particle size, DSC (differential scanning calorimetric), mucoadhesive property, gastroretentive time and drug release studies. Results: The best drug to polymer ratio of microparticles was 1:2.5 (F1) with Na-Alg and 1:7.5 (F4) with Alg-Na with pectin, respectively. The microparticles F1 and F4 showed 28.80%, 50.01% loading efficiency, 82.57%, 82.31% production yield and 945.4, 899.91 µm mean particle size. DSC showed stable character of piroxicam in drug-loaded microparticles and revealed amorphous form. It was found that microparticles (Na-Alg) prepared had faster release and microparticles (Alg-Na and pectin mixture) prepared had slower release than untreated piroxicam (P < 0.05). Microparticles (mixture of Na-Alg and pectin) exhibited very good percentage of mucoadhesion and flowability properties. Mucoadhesion strength and retention time study showed better retention of piroxicam microparticles in intestine. Besides, there was a significant higher retention of mucoadhesive microparticles in upper GI tract. Conclusions: Algino-pectinate mucoadhesive formulations exhibited promising properties of a sustained release form for piroxicam and provided distinct tissue protection in stomach. PMID:25625047

  5. Study of the potential of the air lift bioreactor for xylitol production in fed-batch cultures by Debaryomyces hansenii immobilized in alginate beads.

    PubMed

    Pérez-Bibbins, Belinda; de Souza Oliveira, Ricardo Pinheiro; Torrado, Ana; Aguilar-Uscanga, María Guadalupe; Domínguez, José Manuel

    2014-01-01

    Cell immobilization has shown to be especially adequate for xylitol production. This work studies the suitability of the air lift bioreactor for xylitol production by Debaryomyces hansenii immobilized in Ca-alginate operating in fed-batch cultures to avoid substrate inhibition. The results showed that the air lift bioreactor is an adequate system since the minimum air flow required for fluidization was even lower than that leading to the microaerobic conditions that trigger xylitol accumulation by this yeast, also maintaining the integrity of the alginate beads and the viability of the immobilized cells until 3 months of reuses. Maximum productivities and yields of 0.43 g/l/h and 0.71 g/g were achieved with a xylose concentration of 60 g/l after each feeding. The xylose feeding rate, the air flow, and the biomass concentration at the beginning of the fed-batch operation have shown to be critical parameters for achieving high productivities and yields. Although a maximum xylitol production of 139 g/l was obtained, product inhibition was evidenced in batch experiments, which allowed estimating at 200 and 275 g/l the IC50 for xylitol productivity and yield, respectively. The remarkable production of glycerol in the absence of glucose was noticeable, which could not only be attributed to the osmoregulatory function of this polyol in conditions of high osmotic pressure caused by high xylitol concentrations but also to the role of the glycerol synthesis pathway in the regeneration of NAD(+) in conditions of suboptimal microaeration caused by insufficient aeration or high oxygen demand when high biomass concentrations were achieved.

  6. Binary immobilization of tyrosinase by using alginate gel beads and poly(acrylamide-co-acrylic acid) hydrogels.

    PubMed

    Yahşi, Ayşe; Sahin, Ferat; Demirel, Gökhan; Tümtürk, Hayrettin

    2005-09-15

    The use of the immobilized and the stable enzymes has immense potential in the enzymatic analysis of clinical, industrial and environmental samples. However, their widespread uses are limited due to the high cost of their production. In this study, binary immobilization of tyrosinase by using Ca-alginate and poly(acrylamide-co-acrylic acid) [P(AAm-co-AA)] was investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined for the free and binary immobilized enzymes. The effects of pH, temperature, storage stability, reuse number and thermal stability on the free and immobilized tyrosinase were also examined. For the free and binary immobilized enzymes on Ca-alginate and P(AAm-co-AA), optimum pH was found to be 7 and 5, respectively. Optimum temperature of the free and immobilized enzymes was observed to be 30 and 35 degrees C, respectively. Reuse number, storage and thermal stability of the free tyrosinase were increased by a result of binary immobilization.

  7. Immobilization of Candida krusei cells producing phytase in alginate gel beads: an application of the preparation of myo-inositol phosphates.

    PubMed

    Quan, C S; Fan, S D; Ohta, Y

    2003-07-01

    Cells of Candida krusei capable of producing phytase were immobilized in Ca-alginate gel beads and used for the preparation of myo-inositol phosphates. The immobilization yield was increased about 5-fold after the beads were treated for 96 h at pH 4.0, 4 degrees C. The increased yield was retained, even after 1 month, when the cells were kept at this temperature and pH. No shift in the pH optima of phytase of the immobilized cells was observed, compared with that of free cells. However, the optimum temperature for the enzyme of the immobilized cells was 55 degrees C, which was 15 degrees C higher than that of free cells. The degradation characteristics of the phytate in immobilized cells packed in a glass column (i.d. 1.2 cm, length 20 cm) were investigated. The variation in the composition of the products results from a change in the flow rate of phytate solution (5 mM). At a flow rate of 1.30 ml/min, a mixture of myo-inositol-2-monophosphate, myo-inositol-1,2,5-triphosphate and myo-inositol-1,2,5,6-tetrakisphosphate was produced, in which the latter two were physiologically active. Also, it was found by NMR analysis that the enzyme of this strain produced only one isomer of each of the inositol phosphates, with the exception of myo-inositol pentakisphosphate. Therefore, the pure isomers were easily isolated using ion-exchange chromatography.

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

    PubMed

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

    2016-11-01

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

  9. Enhanced lipid production by co-cultivation and co-encapsulation of oleaginous yeast Trichosporonoides spathulata with microalgae in alginate gel beads.

    PubMed

    Kitcha, Suleeporn; Cheirsilp, Benjamas

    2014-05-01

    This study attempted to enhance biomass and lipid productivity of an oleaginous yeast Trichosporonoides spathulata by co-culturing with microalgae Chlorella spp., optimizing culture conditions, and encapsulating them in alginate gel beads. The co-culture of the yeast with microalgae Chlorella vulgaris var. vulgaris TISTR 8261 most enhanced overall biomass and lipid productivity by 1.6-fold of the yeast pure culture at 48 h and by 1.1-fold at 72 h. After optimization and scale-up in a bioreactor, this co-culture produced the highest biomass of 12.2 g/L with a high lipid content of 47 %. The dissolved oxygen monitoring system in the bioreactor showed that the microalgae worked well as an oxygen supplier to the yeast. This study also showed that the co-encapsulated yeast and microalgae could grow and produce lipid as same as their free cells did. Therefore, it is possible to apply this encapsulation technique for lipid production and simplification of downstream harvesting process. This co-culture system also produced the lipid with high content of saturated fatty acids, indicating its potential use as biodiesel feedstock with high oxidative stability.

  10. Statistical optimization of alpha-amylase production by Streptomyces erumpens MTCC 7317 cells in calcium alginate beads using response surface methodology.

    PubMed

    Kar, Shaktimay; Ray, Ramesh C

    2008-01-01

    Alpha-amylase has a wide range of applications in starch industries, i.e. baking, brewing, distillery, etc. The alpha-amylase production from Streptomyces erumpens MTCC 7317 immobilized cells was compared with that of free cells. The immobilized cells of S. erumpens in calcium alginate beads were more effective for production of alpha-amylase (12.2% more yield) than free cells. Response surface methodology (RSM) was used to evaluate the effect of main variables, i.e. incubation period, pH and temperature on enzyme production with immobilized cells. A full factorial Central Composite Design (CCD) was applied to study these main factors that affected alpha-amylase production. The experimental results showed that the optimum incubation period, pH and temperature were 36 h, 6.0 and 50 degrees C, respectively for immobilized cells. Repeated batch fermentation of immobilized cells in shake flasks carried out in starch-beef extract medium showed that S. erumpens cells were physiologically active on the support even after four cycles of fermentation.

  11. Synthesis of magnetic alginate beads based on Fe3O4 nanoparticles for the removal of 3-methylindole from aqueous solution using Fenton process.

    PubMed

    Hammouda, Samia Ben; Adhoum, Nafaâ; Monser, Lotfi

    2015-08-30

    A novel magnetic heterogeneous catalyst has been developed by incorporation of iron(II) and magnetic functionalized nanoparticles Fe3O4 in alginate beads with the aim of using them in the advanced Fenton oxidation of a malodorous compound (3 methyl-indole: 3-MI). The effects of significant operational parameters such as initial pH, oxidant concentration and catalyst amount were investigated and optimized for a better removal of 3-MI at initial concentration of 20mgL(-1). Besides, the catalyst stability was evaluated according to the iron leached into the aqueous solution. Results revealed that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimized conditions, the magnetic catalyst exhibited a good catalytic performance. Total removal of 3 methyl indole and a remarkable organic mineralization, without significant leaching of iron, were attained within 120min at pH 3.0 by using 0.4gL(-1) of Fe-MABs and 9.8mmolL(-1) of H2O2. The novel magnetic catalyst would be of potential application due to its high efficiency, easy recovery and good structural stability. PMID:25867585

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

    PubMed

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

    2016-11-01

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

  13. Preparation and characterization of immobilized [A336][MTBA] in PVA-alginate gel beads as novel solid-phase extractants for an efficient recovery of Hg (II) from aqueous solutions.

    PubMed

    Zhang, Yun; Kogelnig, Daniel; Morgenbesser, Cornelia; Stojanovic, Anja; Jirsa, Franz; Lichtscheidl-Schultz, Irene; Krachler, Regina; Li, Yanfeng; Keppler, Bernhard K

    2011-11-30

    The coarse PVA-alginate matrix gel beads entrapping the micro-droplets of the ionic liquid tricaprylylmethylammonium 2-(methylthio) benzoate ([A336][MTBA]) as novel solid-phase extractants were prepared for the removal of mercury (II) from aqueous media. The ionic liquid [A336][MTBA] immobilized PVA-alginate beads (PVA/IL) have been characterized by FTIR, SEM and TGA. The influence of the uptake conditions was investigated including aqueous pH, PVA/IL dosage, the content of [A336][MTBA] and initial Hg (II) concentration; maximum Hg (II) ion adsorption capacity obtained was 49.89 (± 0.11)mgg(-1) at pH 5.8 with adsorptive removal of approximately 99.98%. The selectivity of the PVA/IL beads towards Hg (II), Pb (II) and Cu (II) ions tested was Hg>Pb>Cu. The rate kinetic study was found to follow second-order and the applicability of Langmuir, Freundlich and Tempkin adsorption isotherm model were tested as well. The results of the study showed that PVA/IL beads could be efficiently used as novel extractants for the removal of divalent mercury from aqueous solutions under comparatively easy operation conditions.

  14. Kinetic Characterization and Effect of Immobilized Thermostable β-Glucosidase in Alginate Gel Beads on Sugarcane Juice

    PubMed Central

    Keerti; Gupta, Anuradha; Dubey, Ashutosh; Verma, A. K.

    2014-01-01

    A thermostable β-glucosidase was effectively immobilized on alginate by the method of gel entrapment. After optimization of immobilized conditions, recovered enzyme activity was 60%. Optimum pH, temperature, kinetic parameters, thermal and pH stability, reusability, and storage stability were investigated. The Km and Vmax for immobilized β-glucosidase were estimated to be 5.0 mM and 0.64 U/ml, respectively. When comparing, free and immobilized enzyme, change was observed in optimum pH and temperature from 5.0 to 6.0 and 60°C to 80°C, respectively. Immobilized enzyme showed an increase in pH stability over the studied pH range (3.0–10.0) and stability at temperature up to 80°C. The storage stability and reusability of the immobilized β-glucosidase were improved significantly, with 12.09% activity retention at 30°C after being stored for 25 d and 17.85% residual activity after being repeatedly used for 4 times. The effect of both free and immobilized β-glucosidase enzyme on physicochemical properties of sugarcane juice was also analyzed. PMID:25969764

  15. Adsorption of As(III), As(V) and Cu(II) on zirconium oxide immobilized alginate beads in aqueous phase.

    PubMed

    Kwon, Oh-Hun; Kim, Jong-Oh; Cho, Dong-Wan; Kumar, Rahul; Baek, Seung Han; Kurade, Mayur B; Jeon, Byong-Hun

    2016-10-01

    A composite adsorbent to remove arsenite [As(III)], arsenate [As(V)], and copper [Cu(II)] from aqueous phase was synthesized by immobilizing zirconium oxide on alginate beads (ZOAB). The composition (wt%) of ZOAB (Zr-34.0; O-32.7; C-21.3; Ca-1.0) was confirmed by energy dispersive X-ray (EDX) analysis. Sorption studies were conducted on single and binary sorbate systems, and the effects of contact time, initial adsorbate concentration, and pH on the adsorption performance of ZOAB (pHPZC = 4.3) were monitored. The sorption process for As(III)/As(V) and Cu(II) reached an equilibrium state within 240 h and 24 h, respectively, with maximum sorption capacities of 32.3, 28.5, and 69.9 mg g(-1), respectively. The addition of Cu(II) was favorable for As(V) sorption in contrast to As(III). In the presence of 48.6 mg L(-1) Cu(II), the sorption capacity of As(V) increased from 1.5 to 3.8 mg g(-1) after 240 h. The sorption data for As(III)/As(V) and Cu(II) conformed the Freundlich and Langmuir isotherm models, respectively. The adsorption of As(III), As(V), and Cu(II) followed pseudo second order kinetics. The effect of arsenic species on Cu(II) sorption was insignificant. The results of present study demonstrated that the synthesized sorbent could be useful for the simultaneous removal of both anionic and cationic contaminants from wastewaters.

  16. Kinetics studies of p-cresol biodegradation by using Pseudomonas putida in batch reactor and in continuous bioreactor packed with calcium alginate beads.

    PubMed

    Mathur, A K; Bala, Shashi; Majumder, C B; Sarkar, S

    2010-01-01

    Present study deals with the biodegradation of p-cresol by using Pseudomonas putida in a batch reactor and a continuous bioreactor packed with calcium alginate beads. The maximum specific growth rate of 0.8121 h(-1) was obtained at 200 mg L(-1) concentration of p-cresol in batch reactor. The maximum p-cresol degradation rate was obtained 6.598 mg L(-1) h(-1) at S(o)=200 mg L(-1) and 62.8 mg L(-1) h(-1) at S(o)=500 mg L(-1) for batch reactor and a continuous bioreactor, respectively. The p-cresol degradation rate of continuous bioreactor was 9 to 10-fold higher than those of the batch reactor. It shows that the continuous bioreactor could tolerate a higher concentration of p-cresol. A Haldane model was also used for p-cresol inhibition in batch reactor and a modified equation similar to Haldane model for continuous bioreactor. The Haldane parameters were obtained as µ(max) 0.3398 h(-1), K(s) 110.9574 mg L(-1), and K(I) 497.6169 mg L(-1) in batch reactor. The parameters used in continuous bioreactor were obtained as D(max) 91.801 mg L(-1) h(-1), K(s) 131.292 mg L(-1), and K(I) 1217.7 mg L(-1). The value K(I) of continuous bioreactor is approximately 2.5 times higher than the batch reactor. Higher K(I) value of continuous bioreactor indicates P. putida can grow at high range of p-cresol concentration. The ability of tolerance of higher p-cresol concentrations may be one reason for biofilm attachment on the packed bed in the continuous operation.

  17. Adsorption of As(III), As(V) and Cu(II) on zirconium oxide immobilized alginate beads in aqueous phase.

    PubMed

    Kwon, Oh-Hun; Kim, Jong-Oh; Cho, Dong-Wan; Kumar, Rahul; Baek, Seung Han; Kurade, Mayur B; Jeon, Byong-Hun

    2016-10-01

    A composite adsorbent to remove arsenite [As(III)], arsenate [As(V)], and copper [Cu(II)] from aqueous phase was synthesized by immobilizing zirconium oxide on alginate beads (ZOAB). The composition (wt%) of ZOAB (Zr-34.0; O-32.7; C-21.3; Ca-1.0) was confirmed by energy dispersive X-ray (EDX) analysis. Sorption studies were conducted on single and binary sorbate systems, and the effects of contact time, initial adsorbate concentration, and pH on the adsorption performance of ZOAB (pHPZC = 4.3) were monitored. The sorption process for As(III)/As(V) and Cu(II) reached an equilibrium state within 240 h and 24 h, respectively, with maximum sorption capacities of 32.3, 28.5, and 69.9 mg g(-1), respectively. The addition of Cu(II) was favorable for As(V) sorption in contrast to As(III). In the presence of 48.6 mg L(-1) Cu(II), the sorption capacity of As(V) increased from 1.5 to 3.8 mg g(-1) after 240 h. The sorption data for As(III)/As(V) and Cu(II) conformed the Freundlich and Langmuir isotherm models, respectively. The adsorption of As(III), As(V), and Cu(II) followed pseudo second order kinetics. The effect of arsenic species on Cu(II) sorption was insignificant. The results of present study demonstrated that the synthesized sorbent could be useful for the simultaneous removal of both anionic and cationic contaminants from wastewaters. PMID:27372261

  18. A Comparison between Ultraviolet Disinfection and Copper Alginate Beads within a Vortex Bioreactor for the Deactivation of Bacteria in Simulated Waste Streams with High Levels of Colour, Humic Acid and Suspended Solids

    PubMed Central

    Thomas, Simon F.; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel M.; Mason, Paul T.; Allen, Michael J.

    2014-01-01

    We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads) is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries. PMID:25541706

  19. A comparison between ultraviolet disinfection and copper alginate beads within a vortex bioreactor for the deactivation of bacteria in simulated waste streams with high levels of colour, humic acid and suspended solids.

    PubMed

    Thomas, Simon F; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel M; Mason, Paul T; Allen, Michael J

    2014-01-01

    We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads) is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries.

  20. Stability of alginate-immobilized algal cells

    SciTech Connect

    Dainty, A.L.; Goulding, K.H.; Robinson, P.K.; Simpkins, I; Trevan, M.D.

    1986-01-01

    Investigations were carried out using immobilized Chlorella cells to determine the diameter, compressibility, tolerance to phosphate chelation, and ability to retain algal cells during incubation of various alginate beads. These physical bead-characteristics were affected by a variety of interactive factors, including multivalent cation type (hardening agent) and cell, cation, and alginate concentration, the latter exhibiting a predominant influence. The susceptibility of alginate beads to phosphate chelation involved a complex interaction of cation type, concentration, and pH of phosphate solution. A scale of response ranging from gel swelling to gel shrinking was observed for a range of conditions. However, stable Ca alginate beads were maintained in incubation media with a pH of 5.5 and a phosphate concentration of 5 micro M. A preliminary investigation into cell leakage from the beads illustrated the importance of maintaining a stable gel structure and limiting cell growth to reduce leakage.

  1. Controlling the magnetic field distribution on the micrometer scale and generation of magnetic bead patterns for microfluidic applications.

    PubMed

    Yu, Xu; Feng, Xuan; Hu, Jun; Zhang, Zhi-Ling; Pang, Dai-Wen

    2011-04-19

    As is well known, controlling the local magnetic field distribution on the micrometer scale in a microfluidic chip is significant and has many applications in bioanalysis based on magnetic beads. However, it is a challenge to tailor the magnetic field introduced by external permanent magnets or electromagnets on the micrometer scale. Here, we demonstrated a simple approach to controlling the local magnetic field distribution on the micrometer scale in a microfluidic chip by nickel patterns encapsulated in a thin poly(dimethylsiloxane) (PDMS) film under the fluid channel. With the precisely controlled magnetic field, magnetic bead patterns were convenient to generate. Moreover, two kinds of fluorescent magnetic beads were patterned in the microfluidic channel, which demonstrated that it was possible to generate different functional magnetic bead patterns in situ, and could be used for the detection of multiple targets. In addition, this method was applied to generate cancer cell patterns.

  2. A novel mechanism of generating extracellular vesicles during apoptosis via a beads-on-a-string membrane structure.

    PubMed

    Atkin-Smith, Georgia K; Tixeira, Rochelle; Paone, Stephanie; Mathivanan, Suresh; Collins, Christine; Liem, Michael; Goodall, Katharine J; Ravichandran, Kodi S; Hulett, Mark D; Poon, Ivan K H

    2015-06-15

    Disassembly of apoptotic cells into smaller fragments (a form of extracellular vesicle called apoptotic bodies) can facilitate removal of apoptotic debris and intercellular communication. However, the mechanism underpinning this process is unclear. While observing monocytes undergoing apoptosis by time-lapse microscopy, we discovered a new type of membrane protrusion that resembles a 'beads-on-a-string' structure. Strikingly, the 'beads' are frequently sheared off the 'string' to form apoptotic bodies. Generation of apoptotic bodies via this mechanism can facilitate a sorting process and results in the exclusion of nuclear contents from apoptotic bodies. Mechanistically, generation of 'beads-on-a-string' protrusion is controlled by the level of actomyosin contraction and apoptopodia formation. Furthermore, in an unbiased drug screen, we identified the ability of sertraline (an antidepressant) to block the formation of 'beads-on-a-string' protrusions and apoptotic bodies. These data uncover a new mechanism of apoptotic body formation in monocytes and also compounds that can modulate this process.

  3. Microfluidics-assisted generation of stimuli-responsive hydrogels based on alginates incorporated with thermo-responsive and amphiphilic polymers as novel biomaterials.

    PubMed

    Karakasyan, C; Mathos, J; Lack, S; Davy, J; Marquis, M; Renard, D

    2015-11-01

    We used a droplet-based microfluidics technique to produce monodisperse responsive alginate-block-polyetheramine copolymer microgels. The polyetheramine group (PEA), corresponding to a propylene oxide /ethylene oxide ratio (PO/EO) of 29/6 (Jeffamine(®) M2005), was condensed, via the amine link, to alginates with various mannuronic/guluronic acids ratios and using two alginate:jeffamine mass ratios. The size of the grafted-alginate microgels varied from 60 to 80 μm depending on the type of alginate used and the degree of substitution. The droplet-based microfluidics technique offered exquisite control of both the dimension and physical chemical properties of the grafted-alginate microgels. These microgels were therefore comparable to isolated grafted-alginate chains in retaining both their amphiphilic and thermo-sensitive properties. Amphiphilicity was demonstrated at the oil-water interface where grafted-alginate microgels were found to decrease interfacial tension by ∼ 50%. The thermo-sensitivity of microgels was clearly demonstrated and a 10 to 20% reduction in size between was evidenced on increasing the temperature above the lower critical solution temperature (TLCST) of Jeffamine. In addition, the reversibility of thermo-sensitivity was demonstrated by studying the oil-water affinity of microgels with temperature after Congo red labeling. Finally, droplet-based microfluidics was found to be a good and promising tool for generating responsive biobased hydrogels for drug delivery applications and potential new colloidal stabilizers for dispersed systems such as Pickering emulsions.

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

    PubMed

    Hester-Reilly, Holly J; Shapley, Nina C

    2007-09-01

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

  5. Aging and microwave effects on alginate/chitosan matrices.

    PubMed

    Wong, Tin Wui; Chan, Lai Wah; Kho, Shyan Bin; Heng, Paul Wan Sia

    2005-06-01

    The influence of microwave irradiation on the drug release properties of freshly prepared and aged alginate, alginate-chitosan and chitosan beads was investigated. The beads were prepared by extrusion method with sulphathiazole as a model drug. The dried beads were subjected to microwave irradiation at 80 W for 10 min, 20 min or three consecutive cycles of 10 and 20 min, respectively. The profiles of drug dissolution, drug content, drug stability, drug polymorphism, drug-polymer interaction, polymer crosslinkage and complexation were determined by dissolution testing, drug content assay, differential scanning calorimetry and Fourier transform infra-red spectroscopy. The chemical stability of drug embedded in beads was unaffected by microwave conditions and length of storage time. The release property of drug was mainly governed by the extent of polymer interaction in beads. The aged alginate beads required intermittent cycles of microwave irradiation to induce drug release retarding effect in contrast to their freshly prepared samples. Unlike the alginate beads, the level of polymer interaction was higher in aged alginate-chitosan beads than the corresponding fresh beads. The drug release retarding property of aged alginate-chitosan beads could be significantly enhanced through subjecting the beads to microwave irradiation for 10 min. No further change in drug release from these beads was observed beyond 30 min of microwave irradiation. Unlike beads containing alginate, the rate and extent of drug released from the aged chitosan beads were higher upon treatment by microwave in spite of the higher degree of polymer interaction shown by the latter on prolonged storage. The observation suggested that the response of polymer matrix to microwave irradiation in induction of drug release retarding property was largely affected by the molecular arrangement of the polymer chains.

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

    PubMed

    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. PMID:23795723

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

    PubMed

    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.

  8. Protein crystallization in hydrogel beads.

    PubMed

    Willaert, Ronnie; Zegers, Ingrid; Wyns, Lode; Sleutel, Mike

    2005-09-01

    The use of hydrogel beads for the crystallization of proteins is explored in this contribution. The dynamic behaviour of the internal precipitant, protein concentration and relative supersaturation in a gel bead upon submerging the bead in a precipitant solution is characterized theoretically using a transient diffusion model. Agarose and calcium alginate beads have been used for the crystallization of a low-molecular-weight (14.4 kDa, hen egg-white lysozyme) and a high-molecular-weight (636.0 kDa, alcohol oxidase) protein. Entrapment of the protein in the agarose-gel matrix was accomplished using two methods. In the first method, a protein solution is mixed with the agarose sol solution. Gel beads are produced by immersing drops of the protein-agarose sol mixture in a cold paraffin solution. In the second method (which was used to produce calcium alginate and agarose beads), empty gel beads are first produced and subsequently filled with protein by diffusion from a bulk solution into the bead. This latter method has the advantage that a supplementary purification step is introduced (for protein aggregates and large impurities) owing to the diffusion process in the gel matrix. Increasing the precipitant, gel concentration and protein loading resulted in a larger number of crystals of smaller size. Consequently, agarose as well as alginate gels act as nucleation promoters. The supersaturation in a gel bead can be dynamically controlled by changing the precipitant and/or the protein concentration in the bulk solution. Manipulation of the supersaturation allowed the nucleation rate to be varied and led to the production of large crystals which were homogeneously distributed in the gel bead.

  9. Perfluorinated alginate for cellular encapsulation.

    PubMed

    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.

  10. Role of Calcium Alginate and Mannitol in Protecting Bifidobacterium

    PubMed Central

    Dianawati, Dianawati; Mishra, Vijay

    2012-01-01

    Fourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins of Bifidobacterium animalis subsp. lactis Bb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (aw) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl2 solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The aw of freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without aw adjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low aws. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low aws. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C). PMID:22843535

  11. Role of calcium alginate and mannitol in protecting Bifidobacterium.

    PubMed

    Dianawati, Dianawati; Mishra, Vijay; Shah, Nagendra P

    2012-10-01

    Fourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins of Bifidobacterium animalis subsp. lactis Bb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (a(w)) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl(2) solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The a(w) of freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without a(w) adjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low a(w)s. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low a(w)s. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C). PMID:22843535

  12. 3D Cell Culture in Alginate Hydrogels

    PubMed Central

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

    2015-01-01

    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. PMID:27600217

  13. 3D Cell Culture in Alginate Hydrogels

    PubMed Central

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

    2015-01-01

    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.

  14. 3D Cell Culture in Alginate Hydrogels.

    PubMed

    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.

  15. Generation of Internal-Image Functional Aptamers of Okadaic Acid via Magnetic-Bead SELEX

    PubMed Central

    Lin, Chao; Liu, Zeng-Shan; Wang, Dong-Xu; Li, Lin; Hu, Pan; Gong, Sheng; Li, Yan-Song; Cui, Cheng; Wu, Zong-Cheng; Gao, Yang; Zhou, Yu; Ren, Hong-Lin; Lu, Shi-Ying

    2015-01-01

    Okadaic acid (OA) is produced by Dinophysis and Prorocentrum dinoflagellates and primarily accumulates in bivalves, and this toxin has harmful effects on consumers and operators. In this work, we first report the use of aptamers as novel non-toxic probes capable of binding to a monoclonal antibody against OA (OA-mAb). Aptamers that mimic the OA toxin with high affinity and selectivity were generated by the magnetic bead-assisted systematic evolution of ligands by exponential enrichment (SELEX) strategy. After 12 selection rounds, cloning, sequencing and enzyme-linked immunosorbent assay (ELISA) analysis, four candidate aptamers (O24, O31, O39, O40) were selected that showed high affinity and specificity for OA-mAb. The affinity constants of O24, O31, O39 and O40 were 8.3 × 108 M−1, 1.47 × 109 M−1, 1.23 × 109 M−1 and 1.05 × 109 M−1, respectively. Indirect competitive ELISA was employed to determine the internal-image function of the aptamers. The results reveal that O31 has a similar competitive function as free OA toxin, whereas the other three aptamers did not bear the necessary internal-image function. Based on the derivation of the curvilinear equation for OA/O31, the equation that defined the relationship between the OA toxin content and O31 was Y = 2.185X − 1.78. The IC50 of O31 was 3.39 ng·mL−1, which was close to the value predicted by the OA ELISA (IC50 = 4.4 ng·mL−1); the IC10 was 0.33 ng·mL−1. The above data provides strong evidence that internal-image functional aptamers could be applicable as novel probes in a non-toxic assay. PMID:26694424

  16. Removal of uranium and other metals from wastewaters using calcium alginate and bacteria immobilized in calcium alginate

    SciTech Connect

    Gardner, K.R.; Montgomery, J.R.; Adams, D.J.

    1995-12-31

    Calcium alginate beads, containing immobilized bacteria, removed turanium and other metals from mine wastewaters. Batch tests using 2% calcium alginate beads with and without immobilized bacteria showed both were effective at removing uranium. Beads containing live and dead cells removed essentially the same amount of uranium and removed significantly more uranium than beads without bacteria. The bacteria-alginate system was used to treat waters containing 24.5 mg/L uranium and produced effluents containing 1.0 mg/L uranium in 1 hr and <0.1 mg/L uranium in 24 hr. Calcium alginate beads, with and without immobilized bacteria, also removed arsenic, selenium, and other metals from wastewaters. Bacteria investigated for immobilization in the alginate beads include Bacillus and Pseudomonas sp. A spray technique using an air nozzle has been tested to disperse the alginate into mine wastewater eliminating the bead-making process. Ninety-nine percent of the uranium was removed in less than 15 min contact.

  17. Immobilization of lipase using hydrophilic polymers in the form of hydrogel beads.

    PubMed

    Betigeri, Seema S; Neau, Steven H

    2002-09-01

    The purpose of this study was to immobilize lipase (triacylglycerol ester hydrolase, E.C. 3.1.1.3) from Candida rugosa using various polymers in the form of beads, to evaluate enzyme loading, leaching, and activity; and to characterize the beads. Agarose, alginate, and chitosan were the polymers selected to immobilize lipase by entrapment. Agarose beads exhibited undesirable swelling in the leaching and activity medium and the polymer was not used further. Alginate or chitosan beads were prepared by ionic gelation using calcium chloride or sodium tripolyphosphate, respectively, as the cross-linking agent in the gelling solution. Some hatches of beads of each polymer were freeze dried. The results show that alginate beads leached substantially more enzyme than did chitosan beads. Entrapment efficiency, however, was the same for different chitosan levels as well as different alginate levels (43-50%). Activity in alginate was low at 240 +/- 33 and 220 +/- 26, compared to 1,110 +/- 51 and 1,150 +/- 11 units/ml in chitosan, for fresh and freeze-dried beads, respectively. The higher lipase activity in chitosan beads compared to that in alginate beads could be attributed to an alginate-enzyme interaction. It can be concluded that chitosan is a polymer worthy of pursuit to immobilize lipase.

  18. Stability of alginate microbead properties in vitro

    PubMed Central

    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

  19. Enzyme-mediated spatial segregation on individual polymeric support beads: application to generation and screening of encoded combinatorial libraries.

    PubMed Central

    Vágner, J; Barany, G; Lam, K S; Krchnák, V; Sepetov, N F; Ostrem, J A; Strop, P; Lebl, M

    1996-01-01

    Proteolysis of short N alpha-protected peptide substrates bound to polyoxyethylene-polystyrene beads releases selectively free amino sites in the enzyme-accessible "surface" area. The substantial majority of functional sites in the "interior" of the polymeric support are not reached by the enzyme and remain uncleaved (protected). Subsequent synthesis with two classes of orthogonal protecting groups-N alpha-tert-butyloxycarbonyl (Boc) and N alpha-9-fluorenylmethyloxy-carbonyl (Fmoc)-allows generation of two structures on the same bead. The surface structure is available for receptor interactions, whereas the corresponding interior structure is used for coding. Coding structures are usually readily sequenceable peptides. This "shaving" methodology was illustrated by the preparation of a peptide-encoded model peptide combinatorial library containing 1.0 x 10(5) members at approximately 6-fold degeneracy. From this single library, good ligands were selected for three different receptors: anti-beta-endorphin anti-body, streptavidin, and thrombin, and the binding structures were deduced correctly by sequencing the coding peptides present on the same beads. PMID:8710846

  20. Preparation, characterisation and viability of encapsulated Trichoderma harzianum UPM40 in alginate-montmorillonite clay.

    PubMed

    Adzmi, Fariz; Meon, Sariah; Musa, Mohamed Hanafi; Yusuf, Nor Azah

    2012-01-01

    Microencapsulation is a process by which tiny parcels of an active ingredient are packaged within a second material for the purpose of shielding the active ingredient from the surrounding environment. This study aims to determine the ability of the microencapsulation technique to improve the viability of Trichoderma harzianum UPM40 originally isolated from healthy groundnut roots as effective biological control agents (BCAs). Alginate was used as the carrier for controlled release, and montmorillonite clay (MMT) served as the filler. The encapsulated Ca-alginate-MMT beads were characterised using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The FTIR results showed the interaction between the functional groups of alginate and MMT in the Ca-alginate-MMT beads. Peaks at 1595, 1420 and 1020 cm(-1) characterised alginate, and peaks at 1028 and 453 cm(-1) characterised MMT; both sets of peaks appeared in the Ca-alginate-MMT FTIR spectrum. The TGA analysis showed an improvement in the thermal stability of the Ca-alginate-MMT beads compared with the alginate beads alone. SEM analysis revealed a homogeneous distribution of the MMT particles throughout the alginate matrix. T. harzianum UPM40 was successfully encapsulated in the Ca-alginate-MMT beads. Storage analysis of the encapsulated T. harzianum UPM40 showed that the low storage temperature of 5°C resulted in significantly (p < 0.05) better storage compared with room temperature (30°C). PMID:22309479

  1. Montmorillonite-Alginate Composites as a Drug delivery System: Intercalation and In vitro Release of Diclofenac sodium

    PubMed Central

    Kevadiya, B. D.; Patel, H. A.; Joshi, G. V.; Abdi, S. H. R.; Bajaj, H. C.

    2010-01-01

    Diclofenac sodium and alginate was intercalated into montmorillonite to form uniform sized beads by gelation method. The structure and surface morphology of the synthesized composite beads were characterized by powdered X-ray diffraction, Fourier transform infrared spectroscopy, thermo gravimetric analysis and scanning electron microscopy. Diclofenac release kinetics of the composite in simulated intestinal fluid medium (pH 7.4) and effect of montmorillonite content on the in vitro release of diclofenac from diclofenac-montmorillonite-alginate composites bead was investigated by UV/Vis spectrophotometer. Diclofenac encapsulation efficiency in the montmorillonite-alginate composites bead increases with an increase in the montmorillonite content. The control release of diclofenac from diclofenac-montmorillonite-alginate composites beads was observed to be better as compared to diclofenac-alginate beads. PMID:21969745

  2. Polygalacturonase production by calcium alginate immobilized Enterobacter aerogenes NBO2 cells.

    PubMed

    Darah, I; Nisha, M; Lim, Sheh-Hong

    2015-03-01

    Bacterial cells of Enterobacter aerogenes NBO2 were entrapped in calcium alginate beads in order to enhance polygalacturonase production compared to free cells. The optimized condition of 5 % (w/v) sodium alginate concentration, agitation speed of 250 rpm, and 15 beads of calcium alginate with inoculum size of 4 % (v/v; 5.4 × 10(7) cells/ml) produced 23.48 U/mL of polygalacturonase compared to free cells of 18.54 U/ml. There was about 26.6 % increment in polygalaturonase production. However, in this study, there was 296.6 % of increment in polygalacturonase production after improvement parameters compared to before improvement parameters of calcium alginate bead immobilization cells (5.92 U/ml). This research has indicated that optimized physical parameters of calcium alginate bead immobilization cells have significantly enhanced the production of polygalacturonase.

  3. Gel bead composition for metal adsorption

    DOEpatents

    Scott, Charles D.; Woodward, Charlene A.; Byers, Charles H.

    1991-01-01

    The invention is a gel bead comprising propylene glycol alginate and bone gelatin and is capable of removing metals such as Sr and Cs from solution without adding other adsorbents. The invention could have application to the nuclear industry's waste removal activities.

  4. Gel bead composition for metal adsorption

    DOEpatents

    Scott, Charles D.; Woodward, Charlene A.; Byers, Charles H.

    1990-01-01

    The invention is a gel bead comprising propylene glycol alginate and bone gelatin and is capable of removing metals such as Sr and Cs from solution without adding other adsorbents. The invention could have application to the nuclear industry's waste removal activities.

  5. Reliability of human serum protein profiles generated with C8 magnetic beads assisted MALDI-TOF mass spectrometry.

    PubMed

    de Noo, Mirre E; Tollenaar, Rob A E M; Ozalp, Aliye; Kuppen, Peter J K; Bladergroen, Marco R; Eilers, Paul H C; Deelder, André M

    2005-11-15

    Protein profiling with mass spectrometry is a promising approach for classification and identification of biomarkers; however, there is debate about measurement quality and reliability. Here, we present a pipeline for preprocessing, statistical data analysis and presentation. Serum samples of 16 healthy individuals are used to generate protein profiles with high-resolution MALDI-TOF after isolation of peptides with C8 magnetic beads. Analysis of variance was performed after binning, baseline correction and normalization of the mean spectra. Relative variations in the spectra are expressed as coefficient of variation, which depending on the respective preanalytical variation parameter investigated, was found to range between 0.15 and 0.67 in this study. With this novel method, the reproducibility of our protein profiling procedure could be quantified. We showed that circadian rhythm and the number of freeze-thaw cycles had relatively limited influence on serum protein profiles, whereas the period between collection and serum centrifugation had a more pronounced effect.

  6. Enhanced Ionic Conductivity and Power Generation Using Ion-Exchange Resin Beads in a Reverse-Electrodialysis Stack.

    PubMed

    Zhang, Bopeng; Gao, Haiping; Chen, Yongsheng

    2015-12-15

    Reverse electrodialysis (RED) is a promising technique for harvesting energy by mixing seawater with river water. The energy production is usually limited by ionic conductivity in dilute compartments of a RED system. Novel tests were conducted in this research, which used ion-exchange resin beads (IERB) to replace nonconductive spacer fabrics in RED compartments with dilute NaCl solution in a modified stack containing Fumasep FKS and Fumasep FAS membranes. We compared the conductivity of an IERB packed bed with that of an inert glass-beads-packed bed as a control to confirm IERB's effectiveness. When applied in a RED system, IERB decreased the stack resistance by up to 40%. The maximum gross power density improved by 83% in the RED stack compared to that in a regular RED stack at 1.3 cm/s average linear flow velocity. IERB-filled stack resistance was modeled. The model results fit well with experimental data, thereby confirming the effectiveness of the new approach presented here. The net power density is also estimated based on the measured pressure drop and pumping energy model. Both gross and net power density was improved by over 75% at higher flow rate. A net power density of 0.44 W/m(2) was achieved at a cell thickness of 500 μm. To the best of our knowledge, this research is the first to study the impact of IERB on power generation and establishes a new approach to improving the power performance of a RED system.

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

    PubMed Central

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

    2015-01-01

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

  8. To bead or not to bead.

    PubMed

    Dudley, Mark E

    2003-01-01

    To bead or not to bead, that is the question posed by Ito et al. in this issue of the Journal of Immunotherapy. The generation of tumor-reactive T cells remains a major impediment to the wider application of adoptive cell transfer (ACT) therapy for the treatment of patients with cancer. Ito et al. used lymph nodes of mice draining implanted sarcomas as an enriched source of tumor antigen-specific cells. They investigated the ex vivo activation of the lymph node cells by artificial antigen presenting cells (aAPCs) for the production of therapeutic T cell cultures. The optimal aAPC consisted of magnetic beads coated with anti-CD3 and anti-CD28 antibodies. Short-term ex vivo culture with the aAPCs led to a selective expansion and/or activation of tumor antigen specific CD4+ cells. These results lay a solid foundation for the clinical application of bead-based T cell activation, and promote efforts to develop the therapeutic strategy of in vivo immunization, ex vivo T cell activation, and adoptive cell transfer. PMID:12806272

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

    PubMed

    Li, Haibin; Jiang, Fei; Ye, Song; Wu, Yingying; Zhu, Kaiping; Wang, Deping

    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. PMID:26952484

  10. Transarterial Chemoembolization for Hepatocellular Carcinoma with a New Generation of Beads: Clinical–Radiological Outcomes and Safety Profile

    SciTech Connect

    Spreafico, Carlo Cascella, Tommaso; Facciorusso, Antonio Sposito, Carlo; Rodolfo, Lanocita Morosi, Carlo Civelli, Enrico M. Vaiani, Marta; Bhoori, Sherrie; Pellegrinelli, Alessandro; Marchianò, Alfonso; Mazzaferro, Vincenzo

    2015-02-15

    PurposeTo evaluate the short-term safety and efficacy of the new generation of 70–150 µm drug-eluting beads (M1 DEB) in patients with hepatocellular carcinoma undergoing transarterial chemoembolization (TACE) as a primary therapy or as a bridge to liver transplantation (LT).MethodsForty-five consecutive patients underwent TACE with M1 DEB loaded with doxorubicin (DEBDOX/M1). Clinical data were recorded at 12, 24, and 48 h, 7 and 30 days after treatment. Response was assessed by computed tomographic scan according to the modified response evaluation criteria in solid tumors criteria, and a second DEBDOX/M1 TACE was scheduled within 6 weeks in case of a noncomplete response.ResultsAll patients had well-compensated cirrhosis (97.7 % Child A, 44.4 % hepatitis C virus, median age 61 years). Twenty patients (44.4 %) had Barcelona Clinic for Liver Cancer class B disease; the median number of nodules and their sum of diameters were 2 (range 1–6) and 43 mm (range 10–190), respectively. The mean number of TACE procedures per patient was 1.4. Objective response rate (complete + partial response) was 77.7 % with a median time to best response of 3 months (95 % confidence interval 2–4). In 13 patients, DEBDOX/M1 TACE served as a bridge/downstaging to LT/surgery. Pathology showed that more than 90 % necrosis was achieved in 10 of 28 nodules. DEBDOX/M1 TACE was well tolerated, and the grade 3/4 adverse event rate was low (1 of 65 procedures).ConclusionDEBDOX/M1 TACE is an effective procedure with a favorable safety profile and promising results in terms of objective response rate, tumor downstaging, and necrosis.

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

    NASA Astrophysics Data System (ADS)

    Mauri, Marco; Vicini, Silvia; Castellano, Maila

    2016-05-01

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

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

    SciTech Connect

    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).

  13. An electrohydrodynamic bioprinter for alginate hydrogels containing living cells.

    PubMed

    Gasperini, Luca; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2015-02-01

    In this work we present a bioprinting technique that exploits the electrohydrodynamic process to obtain a jet of liquid alginate beads containing cells. A printer is used to microfabricate hydrogels block by block following a bottom-up approach. Alginate beads constitute the building blocks of the microfabricated structures. The beads are placed at predefined position on a target substrate made of calcium-enriched gelatin, where they crosslink upon contact without the need of further postprocessing. The printed sample can be easily removed from the substrate at physiological temperature. Three-dimensional printing is accomplished by the deposition of multiple layers of hydrogel. We have investigated the parameters influencing the process, the compatibility of the printing procedure with cells, and their survival after printing.

  14. Adsorption of a cationic dye, methylene blue, on to chitosan hydrogel beads generated by anionic surfactant gelation.

    PubMed

    Chatterjee, Sudipta; Chatterjee, Tania; Lim, Seong-Rin; Woo, Seung H

    2011-10-01

    Chitosan hydrogel beads (CSB) formed by sodium dodecyl sulphate (SDS) gelation were used for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The adsorption capacity of chitosan beads (CB) formed by alkali gelation was low because of charge repulsions between the chitosan (CS) and the MB. The adsorption capacity of CSB (4 g/L SDS gelation) for MB (100 mg/L) was 129.44 mg/g, and it decreased significantly with increasing SDS concentration during gelation. This decrease was a result of increased density of the CSB membrane materials. The CSB membrane materials formed with the 4 g/L SDS gelation showed the highest volumetric adsorption capacity. The MB adsorption on to CB and CSB increased with increasing values for the initial pH of solution. Data from both CB and CSB showed good fit to Sips isotherm models, and the maximum adsorption capacity of CSB (226.24 mg/g) was higher than that of CB (99.01 mg/g).

  15. "Artificial mitotic spindle" generated by dielectrophoresis and protein micropatterning supports bidirectional transport of kinesin-coated beads.

    PubMed

    Uppalapati, Maruti; Huang, Ying-Ming; Aravamuthan, Vidhya; Jackson, Thomas N; Hancock, William O

    2011-01-01

    The mitotic spindle is a dynamic assembly of microtubules and microtubule-associated proteins that controls the directed movement of chromosomes during cell division. Because proper segregation of the duplicated genome requires that each daughter cell receives precisely one copy of each chromosome, numerous overlapping mechanisms have evolved to ensure that every chromosome is transported to the cell equator during metaphase. However, due to the inherent redundancy in this system, cellular studies using gene knockdowns or small molecule inhibitors have an inherent limit in defining the sufficiency of precise molecular mechanisms as well as quantifying aspects of their mechanical performance. Thus, there exists a need for novel experimental approaches that reconstitute important aspects of the mitotic spindle in vitro. Here, we show that by microfabricating Cr electrodes on quartz substrates and micropatterning proteins on the electrode surfaces, AC electric fields can be used to assemble opposed bundles of aligned and uniformly oriented microtubules as found in the mitotic spindle. By immobilizing microtubule ends on each electrode, analogous to anchoring at centrosomes, solutions of motor or microtubule binding proteins can be introduced and their resulting dynamics analyzed. Using this "artificial mitotic spindle" we show that beads functionalized with plus-end kinesin motors move in an oscillatory manner analogous to the movements of chromosomes and severed chromosome arms during metaphase. Hence, features of directional instability, an established characteristic of metaphase chromosome dynamics, can be reconstituted in vitro using a pair of uniformly oriented microtubule bundles and a plus-end kinesin functionalized bead.

  16. Immobilization of alginate-encapsulated Bacillus thuringiensis var. israelensis containing different multivalent counterions for mosquito control.

    PubMed

    Prabakaran, G; Hoti, S L

    2008-08-01

    Immobilized techniques have been used widely for the controlled release formulation of mosquitoes. Among the microbial formulations, polymeric matrices play an important role in the controlled release of microbial pesticide at rates sufficiently effective to kill mosquitoes in the field. The advantage of these matrices is that they enhance the stability of both spores and toxin against pH, temperature variations, and UV irradiation. The disadvantage of using calcium alginate beads is that they are unstable upon contact with phosphate of potassium or sodium ions rich in the mosquito habitats. To overcome these problems, attempts were made to encapsulate Bacillus thuringiensis var. israelensis within alginate by using different multivalent counterions, namely, calcium chloride, zinc sulfate, copper sulfate, cobalt chloride, and ferric chloride, and the beads formed were tested for its mosquito larvicidal activity. Among all the beads tested, zinc alginate beads resulted in maximum larvicidal activity of 98% (+/-1.40 SE) against Culex quinquefasciatus IIIrd instar larvae and maximum spore count of 3.36 x 10(5) (+/-5291.50 SE) CFU/ml. Zinc alginate beads maintained their structure for up to 48 h when shaken vigorously on a rotary shaker at 180 rpm in the presence of 10 mM potassium phosphate buffer (pH 6.8 +/- 0.1). In conclusion, our results suggest that the use of zinc sulfate as counterions to encapsulate B. thuringiensis var. israelensis within alginate may be a potent mosquito control program in the habitats where more phosphate ions are present.

  17. Zinc cross-linked hydroxamated alginates for pulsed drug release

    PubMed Central

    Raut, Neha S; Deshmukh, Prasad R; Umekar, Milind J; Kotagale, Nandkishor R

    2013-01-01

    Introduction: Alginates can be tailored chemically to improve solubility, physicochemical, and biological properties and its complexation with metal ion is useful for controlling the drug release. Materials And Methods: Synthesized N,O-dimethyl, N-methyl, or N-Benzyl hydroxylamine derivatives of sodium alginate were subsequently complexed with zinc to form beads. Hydroxamation of sodium alginate was confirmed by Fourier transform infra-red spectroscopy (FTIR) and differential scanning calorimetry (DSC). Results: The synthesized polymeric material exhibited reduced aqueous, HCl and NaOH solubility. The hydroxamated derivatives demonstrated pulsed release where change in pH of the dissolution medium stimulated the atenolol release. Conclusion: Atenolol loaded Zn cross-linked polymeric beads demonstrated the sustained the plasma drug levels with increased half-life. Although the synthesized derivatives greatly altered the aqueous solubility of sodium alginate, no significant differences in in vitro and in vivo atenolol release behavior amongst the N,O-dimethyl, N-methyl, or N-Benzyl hydroxylamine derivatives of sodium alginate were observed. PMID:24350039

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

    PubMed

    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.

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

    PubMed

    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. PMID:27540886

  20. Microfluidic Directed Synthesis of Alginate Nanogels with Tunable Pore Size for Efficient Protein Delivery.

    PubMed

    Bazban-Shotorbani, Salime; Dashtimoghadam, Erfan; Karkhaneh, Akbar; Hasani-Sadrabadi, Mohammad Mahdi; Jacob, Karl I

    2016-05-17

    Alginate is a biopolymer with favorable pH-sensitive properties for oral delivery of peptides and proteins. However, conventional alginate nanogels have limitations such as low encapsulation efficiency because of drug leaching during bead preparation and burst release in high pH values. These shortcomings originate from large pore size of the nanogels. In this work, we proposed an on-chip hydrodynamic flow focusing approach for synthesis of alginate nanogels with adjustable pore size to achieve fine-tunable release profile of the encapsulated bioactive agents. It is demonstrated that the microstructure of nanogels can be controlled through adjusting flow ratio and mixing time directed on microfluidic platforms consisting of cross-junction microchannels. In this study, the average pore size of alginate nanogels (i.e., average molecular weight between cross-links, Mc) was related to synthesis parameters. Mc was calculated from equations based on equilibrium swelling theory and proposed methods to modify the theory for pH-sensitive nanogels. In the equations we derived, size and compactness of nanogels are key factors, which can be adjusted by controlling the flow ratio. It was found that increase in flow ratio increases the size of nanogels and decreases their compactness. The size of on-chip generated nanogels for flow ratio of 0.02-0.2 was measured to be in the range of 68-138 nm. Moreover, a method based on the Mie theory was implemented to estimate the aggregation number (Nagg) of polymer chains inside the nanogels as an indicator of compactness. According to the size and compactness results along with equations of modified swelling theory, Mc obtained to be in the range of 0.5-0.8 kDa. The proposed method could be considered as a promising approach for efficient polypeptides encapsulation and their sustained release. PMID:26938744

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

    PubMed Central

    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

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

    PubMed

    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. PMID:22203513

  3. Next Generation Gene Synthesis by targeted retrieval of bead-immobilized, sequence verified DNA clones from a high throughput pyrosequencing device

    PubMed Central

    Matzas, Mark; Stähler, Peer F.; Kefer, Nathalie; Siebelt, Nicole; Boisguérin, Valesca; Leonard, Jack T.; Keller, Andreas; Stähler, Cord F.; Häberle, Pamela; Gharizadeh, Baback; Babrzadeh, Farbod; Church, George

    2012-01-01

    The setup of synthetic biological systems involving millions of bases is still limited by the required high quality of synthetic DNA. Important drivers to further open up the field are the accuracy and scale of chemical DNA synthesis and the downstream processing of longer DNA assembled from short fragments. We developed a new, highly parallel and miniaturized method for the preparation of high quality DNA termed “Megacloning” by using Next Generation Sequencing (NGS) technology in a preparative way. We demonstrate our method by processing both conventional and microarray-derived DNA oligonucleotides in combination with a bead-based high throughput pyrosequencing platform, gaining a 500-fold error reduction for microarray oligonucleotides in a first embodiment. We also show the assembly of synthetic genes as part of the Megacloning process. In principle, up to millions of DNA fragments can be sequenced, characterized and sorted in a single Megacloner run, enabling many new applications. PMID:21113166

  4. Gelatin blends with alginate: gels for lipase immobilization and purification.

    PubMed

    Fadnavis, Nitin W; Sheelu, Gurrala; Kumar, Bezavada Mani; Bhalerao, Mahendra U; Deshpande, Ashlesha A

    2003-01-01

    Blends of natural polysaccharide sodium alginate (5%) with gelatin (3%) cross-linked with glutaraldehyde provide beads with excellent compressive strength (8 x 10(4) Pa) and regular structure on treatment with calcium chloride. Lipases from porcine pancreas, Pseudomonas cepacia, and Candida rugosa were immobilized in such a blend with excellent efficiency. The immobilized enzymes were stable and were reused several times without significant loss of enzyme activity both in aqueous and reverse micellar media. The beads were functionalized with succinic anhydride to obtain beads with extra carboxylic acid groups. These functionalized beads were then successfully used for 7.4-fold purification of crude porcine pancreatic lipase in a simple operation of protein binding at pH 5 and release at pH 8.5.

  5. Evaluation of the use of Sr2+ in alginate immobilization of cells

    NASA Astrophysics Data System (ADS)

    Widerøe, Hege; Danielsen, Signe

    2001-05-01

    In recent years the method of immobilization of living cells in Ca-alginate beads has gained a wide range of applications. In all cases high chemical stability of the immobilization material and mild conditions for the cells are prerequisites. However, in long-term experiments that may last for several days Ca-alginate may dissolve due to an exchange of Ca2+ with Na+, forming fluid Na-alginate. As well as Ca-alginate, the more chemically stable Sr-alginate and Ba-alginate are materials that have been used for the immobilization of living cells. In this study, the effects of Ca2+, Sr2+ and Ba2+ on growth, viability and intracellular free calcium concentration in a human leukemic T cell line (Jurkat) were investigated. The findings in this study, and the fact that Sr-alginate has a considerably higher chemical stability than Ca-alginate, led to the conclusion that Sr-alginate is a more suitable material for use in the entrapment of living cells in long-term studies.

  6. Evaluation of the use of Sr2+ in alginate immobilization of cells.

    PubMed

    Widerøe, H; Danielsen, S

    2001-05-01

    In recent years the method of immobilization of living cells in Ca-alginate beads has gained a wide range of applications. In all cases high chemical stability of the immobilization material and mild conditions for the cells are prerequisites. However, in long-term experiments that may last for several days Ca-alginate may dissolve due to an exchange of Ca2+ with Na+, forming fluid Na-alginate. As well as Ca-alginate, the more chemically stable Sr-alginate and Ba-alginate are materials that have been used for the immobilization of living cells. In this study, the effects of Ca2+, Sr2+ and Ba2+ on growth, viability and intracellular free calcium concentration in a human leukemic T cell line (Jurkat) were investigated. The findings in this study, and the fact that Sr-alginate has a considerably higher chemical stability than Ca-alginate, led to the conclusion that Sr-alginate is a more suitable material for use in the entrapment of living cells in long-term studies.

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

    PubMed

    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.

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

    PubMed Central

    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

  9. Bioacetylation of Seaweed Alginate

    PubMed Central

    Lee, J. W.; Day, D. F.

    1995-01-01

    Seaweed alginate was acetylated by intact, resting cells of Pseudomonas syringae ATCC 19304. Maximum acetylation of this polymer occurred at a pH of 6.0 and a temperature of 25 deg C. Aeration and gluconic acid were required for an optimal reaction. A reactor which contained carbon-immobilized cells was constructed to continuously acetylate alginate. The maximal yield of acetylation was about 90%, and the half-life of this system was 6.5 days. PMID:16534934

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

    PubMed

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

    2009-01-31

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

  11. Expanded polylactide bead foaming - A new technology

    NASA Astrophysics Data System (ADS)

    Nofar, M.; Ameli, A.; Park, C. B.

    2015-05-01

    Bead foaming technology with double crystal melting peak structure has been recognized as a promising method to produce low-density foams with complex geometries. During the molding stage of the bead foams, the double peak structure generates a strong bead-to-bead sintering and maintains the overall foam structure. During recent years, polylactide (PLA) bead foaming has been of the great interest of researchers due to its origin from renewable resources and biodegradability. However, due to the PLA's low melt strength and slow crystallization kinetics, the attempts have been limited to the manufacturing methods used for expanded polystyrene. In this study, for the first time, we developed microcellular PLA bead foams with double crystal melting peak structure. Microcellular PLA bead foams were produced with expansion ratios and average cell sizes ranging from 3 to 30-times and 350 nm to 15 µm, respectively. The generated high melting temperature crystals during the saturation significantly affected the expansion ratio and cell density of the PLA bead foams by enhancing the PLA's poor melt strength and promoting heterogeneous cell nucleation around the crystals.

  12. Comparative investigation of the binding characteristics of poly-L-lysine and chitosan on alginate hydrogel.

    PubMed

    Ren, Ying; Xie, Hongguo; Liu, Xiaocen; Bao, Jie; Yu, Weiting; Ma, Xiaojun

    2016-03-01

    The binding properties of poly-L-lysine and chitosan to alginate have been evaluated quantitatively and compared. Poly-L-lysine bound to alginate hydrogel more rapidly than chitosan as poly-L-lysine has a smaller molar hydrodynamic volume. In addition, poly-L-lysine showed a much higher binding capacity (6.14:1) for alginate hydrogel beads than chitosan (2.71:1), and a little higher binding stoichiometry (0.58) to sodium alginate molecules in solution than chitosan (0.49). An exothermic heat of alginate-poly-L-lysine complexes formation of 2.02 kJ/mol was detected. For alginate-chitosan complexes, the binding enthalpy has been seen to be -3.49 kJ/mol. The stability of the polyelectrolyte complexes was related to their binding enthalpy. The alginate-poly-L-lysine complexes could be disintegrated and rebuilt. By contrast, chitosan was bound with alginate in a steady state. These results provide fundamental insights regarding the structure and property relationships of macromolecules, and will be helpful in designing and selecting appropriate polymers.

  13. Structurally stable gel bead containing entrapped enzyme and method for manufacture thereof

    DOEpatents

    Woodward, Jonathan

    1998-01-01

    A structurally stable gel bead containing an entrapped enzyme and a method for its manufacture. The enzyme is covalently cross-linked to gelatin in the presence of glutaraldehyde prior to the formation of the gel bead, to prevent leakage of the enzyme. Propylene glycol alginate is then added to the mixture. Once the gel beads are formed, they are then soaked in glutaraldehyde, which imparts structural stability to the gel beads. This method can be used with many types of enzymes, such as proteases, carbohydrases, proteases, ligases, isomerases, oxidoreductases, and specialty enzymes. These and other enzymes can be immobilized in the gel beads and utilized in a number of enzymatic processes. Exogenously added ions are not required to maintain the structural stability of these gel beads.

  14. Structurally stable gel bead containing entrapped enzyme and method for manufacture thereof

    DOEpatents

    Woodward, J.

    1998-12-08

    This research provides a structurally stable gel bead containing an entrapped enzyme and a method for its manufacture. The enzyme is covalently cross-linked to gelatin in the presence of glutaraldehyde prior to the formation of the gel bead, to prevent leakage of the enzyme. Propylene glycol alginate is then added to the mixture. Once the gel beads are formed, they are then soaked in glutaraldehyde, which imparts structural stability to the gel beads. This method can be used with many types of enzymes, such as proteases, carbohydrases, proteases, ligases, isomerases, oxidoreductases, and specialty enzymes. These and other enzymes can be immobilized in the gel beads and utilized in a number of enzymatic processes. Exogenously added ions are not required to maintain the structural stability of these gel beads. 7 figs.

  15. Survival of different cell lines in alginate-agarose microcapsules.

    PubMed

    Orive, G; Hernández, R M; Gascón, A R; Igartua, M; Pedraz, J L

    2003-01-01

    Cell microencapsulation has emerged as a promising therapeutic strategy to treat a wide range of diseases. The optimisation of this technology depends on several critical issues such as the careful selection of the cell line, the controlled manufacture of microcapsules and the suitable adaptation of the construct design to the selected cell line. In this work, we studied the behavior of hybridoma cells once enclosed in solid and liquefied core alginate-agarose beads. Results show that hybridoma cells presented a better growing pattern and improved their viability and antibody production within liquefied beads. However, when these beads were evaluated with a compression resistance study, they were found to be mechanically more fragile than solid ones. To address this problem, we entrapped non-autologous cells (BHK fibroblast and C2C12 myoblast) in solid alginate-agarose beads and observed that they showed an improved growing profile and prolonged their viability up to 70 days in comparison to the 15 days seen for the hybridoma cells.

  16. Short-Duration Low-Direct-Current Electrical Field Treatment Is a Practical Tool for Considerably Reducing Counts of Gram-Negative Bacteria Entrapped in Gel Beads

    PubMed Central

    Zvitov, R.; Zohar-Perez, C.; Nussinovitch, A.

    2004-01-01

    Application of a direct-current electrical field for very short times can serve as a practical nonthermal procedure to reduce or modify the microbial distribution in gel beads. The viability of Escherichia coli and Serratia marcescens entrapped in alginate and agarose beads decreases as the field intensity and duration of electrical field increase. PMID:15184192

  17. TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

    PubMed

    Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

    2014-09-01

    The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity. PMID:25063138

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

    PubMed

    Chen, Qingsen; Liu, Jian

    2003-08-01

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

  19. Gelling process for sodium alginate: New technical approach by using calcium rich micro-spheres.

    PubMed

    Vicini, Silvia; Castellano, Maila; Mauri, Marco; Marsano, Enrico

    2015-12-10

    Alginate based materials have become an important class of products in many fields from the pharmaceutical industry to tissue engineering, because of their ability to create stimuli responsive hydrogels. We present a new technical approach for obtaining a controlled gelling process, based on the quantities of Ca(2+) rich alginate micro-beads added as crosslinkers. The gels have been evaluated in light of the amount of Ca(2+) added to the alginate solution, and in light of the different dimensions of the micro-beads, using rheological measurements to assess the variation in the storage modulus (G'), loss modulus (G'') and complex viscosity (η(*)) as well as swelling and deswelling tests. The methodology was developed to obtain a material with specific characteristics for application in the field of conservation. The material had to be able to create a stable gel after being applied on the artwork surface and to confine the solvent action at the interface during cleaning operations.

  20. Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation

    PubMed Central

    Yu, L.; Grist, S. M.; Nasseri, S. S.; Ni, C.; Cheung, K. C.

    2015-01-01

    Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture. PMID:25945144

  1. The use of fibrin beads for tissue engineering and subsequential transplantation.

    PubMed

    Perka, C; Arnold, U; Spitzer, R S; Lindenhayn, K

    2001-06-01

    New biological technologies such as tissue engineering procedures require the transplantation of functionally active cells within supportive carrier matrices. This paper describes a sequential culture procedure for different types of cells. The technique includes the initial preparation of a mixed alginate-fibrin vehicle that guaranteed an initial cell proliferation and differentiation to establish a stable matrix structure, and the subsequent removal of the alginate component prior to transplantation to circumvent the problem of missing bioresorbability. The resulting biodegradable carrier is mechanically stable and promotes further tissue maturation. Chondrocytes, periosteal-derived cells, as well as nucleus pulposus cells were entrapped in fibrin-alginate beads and in fibrin beads. The results indicate a promising technical approach to create stable transplants for reconstructive surgery of cartilage and bone.

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

    PubMed

    Tran, Nhu-Mai; Dufresne, Murielle; Helle, François; Hoffmann, Thomas Walter; François, Catherine; Brochot, Etienne; Paullier, Patrick; Legallais, Cécile; Duverlie, Gilles; Castelain, Sandrine

    2014-01-01

    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.

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

    PubMed

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

    2016-12-01

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

  4. Alginate Hydrogel Protects Encapsulated Hepatic HuH-7 Cells against Hepatitis C Virus and Other Viral Infections

    PubMed Central

    Tran, Nhu-Mai; Dufresne, Murielle; Helle, François; Hoffmann, Thomas Walter; François, Catherine; Brochot, Etienne; Paullier, Patrick; Legallais, Cécile; Duverlie, Gilles; Castelain, Sandrine

    2014-01-01

    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. PMID:25310111

  5. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate is prepared by...

  6. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium alginate. 184.1724 Section 184.1724 Food and... Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate...

  7. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Potassium alginate...

  8. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Calcium alginate is prepared...

  9. A bacteria-based bead for possible self-healing marine concrete applications

    NASA Astrophysics Data System (ADS)

    Palin, D.; Wiktor, V.; Jonkers, H. M.

    2016-08-01

    This work presents a bacteria-based bead for potential self-healing concrete applications in low-temperature marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative marine concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite–alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ∼1 mm3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing concrete in low-temperature marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing concrete research.

  10. A bacteria-based bead for possible self-healing marine concrete applications

    NASA Astrophysics Data System (ADS)

    Palin, D.; Wiktor, V.; Jonkers, H. M.

    2016-08-01

    This work presents a bacteria-based bead for potential self-healing concrete applications in low-temperature marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative marine concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite-alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ˜1 mm3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing concrete in low-temperature marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing concrete research.

  11. Development of coated beads for oral controlled delivery of cefaclor: In vitro evaluation.

    PubMed

    Rasool, Bazigha K Abdul; Fahmy, Sahar A

    2013-03-01

    The aim of the present study was to develop and characterize coated chitosan-alginate beads containing cefaclor as a controlled release delivery system. Coated cefaclor beads were prepared by solvent evaporation techniques. Beads were found to be intact and spherical in shape. Their size range was 1.05 to 2.06. The loading efficiency showed maximum value when the concentration of cefaclor, chitosan and PEG 400 was 10 % (m/V), 0.5 % (m/V) and 2 % (V/V), respectively. Best retardation of cefaclor release from chitosan-alginate beads was achieved by coating with 15 % of shellac in formula F19. A significant antimicrobial activity (p < 0.05) against Staphylococcus aureus and Klebsiella pneumoniae was observed for formula F19 compared to the standard antibiotic disc. Furthermore, the simulated plasma profile showed the superiority of F19 in sustaining drug release for more than 12 h. Therefore, shellac coated chitosan-alginate beads could be considered a successful controlled release oral cefaclor dosage form.

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

    PubMed

    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. PMID:26344272

  13. Alginate Inhibits Iron Absorption from Ferrous Gluconate in a Randomized Controlled Trial and Reduces Iron Uptake into Caco-2 Cells

    PubMed Central

    Wawer, Anna A.; Harvey, Linda J.; Dainty, Jack R.; Perez-Moral, Natalia; Sharp, Paul; Fairweather-Tait, Susan J.

    2014-01-01

    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. Trial Registration ClinicalTrials.gov NCT01528644 PMID:25391138

  14. Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

    PubMed

    Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Osorio, Coralia; Nazareno, Mónica Azucena

    2016-07-01

    Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples.

  15. Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

    PubMed

    Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Osorio, Coralia; Nazareno, Mónica Azucena

    2016-07-01

    Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples. PMID:26920307

  16. Crosslinked, porous, polyacrylate beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1977-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree. C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  17. Crosslinked, porous, polyacrylate beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

    1976-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  18. Small, porous polyacrylate beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

    1976-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  19. Laser-assisted fabrication of highly viscous alginate microsphere

    NASA Astrophysics Data System (ADS)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  20. Nitrate removal by entrapped zero-valent iron nanoparticles in calcium alginate.

    PubMed

    Krajangpan, Sita; Bermudez, Juan J Elorza; Bezbaruah, Achintya N; Chisholm, Bret J; Khan, Eakalak

    2008-01-01

    Zero-valent iron nanoparticles (nZVI) were successfully entrapped in calcium alginate beads. The potential use of this technique in environmental remediation using nitrate as a model contaminant was investigated. Kinetics of nitrate degradation using bare nZVI (approximately 35 nm dia) and entrapped nZVI were compared. Calcium alginate beads show promise as the entrapment medium for nZVI for possible use in permeable reactive barriers for groundwater remediation. Based on scanning electron microscopy images it can be inferred that the alginate gel cluster acts as a bridge that binds the nZVI particles together. Kinetic experiments with 100, 60, and 20 mg NO3--N L(-1) indicate that 50-73% nitrate-N removal was achieved with entrapped nZVI as compared to 55-73% with bare nZVI over a 2 h period. The controls ran simultaneously show little or no NO3--N removal. Statistical analysis indicates that there was no significant difference between the reaction rates of bare and entrapped nZVI. The authors have shown for the first time that nZVI can be effectively entrapped in Ca-alginate beads and no significant decrease in the reactivity of nZVI toward the model contaminant (nitrate here) was observed after the entrapment.

  1. Apparatus for the production of gel beads containing a biocatalyst

    DOEpatents

    Scott, C.D.; Scott, T.C.; Davison, B.H.

    1998-03-19

    An apparatus is described for the large-scale and continuous production of gel beads containing a biocatalyst. The apparatus is a columnar system based on the chemical cross-linking of hydrocolloidal gels that contain and immobilize a biocatalyst, the biocatalyst being a microorganism or an enzyme. Hydrocolloidal gels, such as alginate, carrageenan, and a mixture of bone gelatin and modified alginate, provide immobilization matrices that can be used to entrap and retain the biocatalyst while allowing effective contact with substrates and release of products. Such immobilized biocatalysts are generally formulated into small spheres or beads that have high concentrations of the biocatalyst within the gel matrix. The columnar system includes a gel dispersion nozzle submerged in a heated non-interacting liquid, typically an organic liquid, that is immiscible with water to allow efficient formation of spherical gel droplets, the non-interacting liquid having a specific gravity that is less than water so that the gel droplets will fall through the liquid by the force of gravity. The heated non-interacting liquid is in direct contact with a chilled upflowing non-interacting liquid that will provide sufficient residence time for the gel droplets as they fall through the liquid so that they will be cooled below the gelling temperature and form solid spheres. The upflowing non-interacting liquid is in direct contact with an upflowing temperature-controlled aqueous solution containing the necessary chemicals for cross-linking or fixing of the gel beads to add the necessary stability. The flow rates of the two liquid streams can be varied to control the proper residence time in each liquid section to accommodate the production of gel beads of differing settling velocities. A valve is provided for continuous removal of the stabilized gel beads from the bottom of the column. 1 fig.

  2. Apparatus for the production of gel beads containing a biocatalyst

    DOEpatents

    Scott, Charles D.; Scott, Timothy C.; Davison, Brian H.

    1998-01-01

    An apparatus for the large-scale and continuous production of gel beads containing a biocatalyst. The apparatus is a columnar system based on the chemical cross-linking of hydrocolloidal gels that contain and immobilize a biocatalyst, the biocatalyst being a microorganism or an enzyme. Hydrocolloidal gels, such as alginate, carrageenan, and a mixture of bone gelatin and modified alginate, provide immobilization matrices that can be used to entrap and retain the biocatalyst while allowing effective contact with substrates and release of products. Such immobilized biocatalysts are generally formulated into small spheres or beads that have high concentrations of the biocatalyst within the gel matrix. The columnar system includes a gel dispersion nozzle submerged in a heated non-interacting liquid, typically an organic liquid, that is immiscible with water to allow efficient formation of spherical gel droplets, the non-interacting liquid having a specific gravity that is less than water so that the gel droplets will fall through the liquid by the force of gravity. The heated non-interacting liquid is in direct contact with a chilled upflowing non-interacting liquid that will provide sufficient residence time for the gel droplets as they fall through the liquid so that they will be cooled below the gelling temperature and form solid spheres. The upflowing non-interacting liquid is in direct contact with an upflowing temperature-controlled aqueous solution containing the necessary chemicals for cross-linking or fixing of the gel beads to add the necessary stability. The flow rates of the two liquid streams can be varied to control the proper residence time in each liquid section to accommodate the production of gel beads of differing settling velocities. A valve is provided for continuous removal of the stabilized gel beads from the bottom of the column.

  3. Antioxidant activity of low molecular weight alginate produced by thermal treatment.

    PubMed

    Kelishomi, Zahra Habibi; Goliaei, Bahram; Mahdavi, Hossein; Nikoofar, Alireza; Rahimi, Mahmood; Moosavi-Movahedi, Ali Akbar; Mamashli, Fatemeh; Bigdeli, Bahareh

    2016-04-01

    By definition, antioxidants are molecules that inhibit the oxidation of other molecules. Therefore, such compounds have very important clinical roles. In this study alginate polymer was depolymerized by heat treatment. The resulting low molecular weight alginates were investigated by UV-visible spectroscopy, Viscometry, Dynamic light scattering and FT-IR spectroscopy techniques. Antioxidant properties of these heat products were studied by ABTS and superoxide radical scavenging assays. Results showed that heating caused breaks in the polymer chain and so generation of low molecular weight alginates. Antioxidant measurements confirmed antioxidant activity of alginate increased upon a decrease in molecular weight. Therefore, low molecular weight alginate produced by heating could be considered as a stronger antioxidant than alginate polymer. These products could be useful for industrial and biomedical applications.

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

    PubMed Central

    Cao, Bao; Christophersen, Lars; Jensen, Peter Østrup; Sneppen, Kim; Høiby, Niels; Moser, Claus

    2016-01-01

    Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100–1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm. PMID:27100887

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

    PubMed

    Cao, Bao; Christophersen, Lars; Kolpen, Mette; Jensen, Peter Østrup; Sneppen, Kim; Høiby, Niels; Moser, Claus; Sams, Thomas

    2016-01-01

    Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100-1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm. PMID:27100887

  6. Understanding Alginate Gel Development for Bioclogging and Biogeophysical Experiments

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    and bioclogging magnitude. However, the alginate concentration was found to be the leading factor for alginate gel yield in the pH range from 4 to 11. Results also suggest that alginate gel may absorb about 25 to 75 percent of dissolved Ca and the magnitude of this sorption depends on the ratio of Ca2+ and alginate concentrations. The absorption of such high concentrations of Ca2+ by the alginate gel may have significant implications on the degree of bioclogging and consequently the SIP response. The generation of the alginate gel within porous media decreased the velocity of liquid flow through solid phase up to 3-5 times. The magnitude of flow decrease was also dependent on the molar ratio between alginate and Ca reacted. The results presented here might be also applied to the optimization of bioremediation because of the stimulating effect of Ca2+ on the generation of biopolymeric gels and hence the development of subsurface biofilm and rate of bioclogging.

  7. Binding and leakage of barium in alginate microbeads.

    PubMed

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

    2012-11-01

    Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) 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 with 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. 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.

  8. Binding and Leakage of Barium in Alginate Microbeads

    PubMed Central

    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

  9. Alginate-encapsulation of shoot tips of jojoba [Simmondsia chinensis (Link) Schneider] for germplasm exchange and distribution.

    PubMed

    Kumar, Sunil; Rai, Manoj K; Singh, Narender; Mangal, Manisha

    2010-12-01

    Shoot tips excised from in vitro proliferated shoots derived from nodal explants of jojoba [Simmondsia chinensis (Link) Schneider] were encapsulated in calcium alginate beads for germplasm exchange and distribution. A gelling matrix of 3 % sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Best response for shoot sprouting from encapsulated shoot tips was recorded on 0.8 % agar-solidified full-strength MS medium. Rooting was induced upon transfer of sprouted shoots to 0.8 % agar-solidified MS medium containing 1 mg l(-1) IBA. About 70 % of encapsulated shoot tips were rooted and converted into plantlets. Plants regenerated from encapsulated shoot tips were acclimatized successfully. The present encapsulation approach could also be applied as an alternative method of propagation of desirable elite genotype of jojoba.

  10. Microfluidic one-step synthesis of alginate microspheres immobilized with antibodies

    PubMed Central

    Chen, Wanyu; Kim, Jong-Hoon; Zhang, Di; Lee, Kyong-Hoon; Cangelosi, G. A.; Soelberg, S. D.; Furlong, C. E.; Chung, Jae-Hyun; Shen, Amy Q.

    2013-01-01

    Micrometre- and submicrometre-size functionalized beads are frequently used to capture targets of interest from a biological sample for biological characterizations and disease diagnosis. The main challenge of the microbead-based assay is in the immobilization of probe molecules onto the microbead surfaces. In this paper, we report a versatile droplet microfluidics method to fabricate alginate microspheres while simultaneously immobilizing anti-Mycobacterium tuberculosis complex IgY and anti-Escherichia coli IgG antibodies primarily on the porous alginate carriers for specific binding and binding affinity tests. The binding affinity of antibodies is directly measured by fluorescence intensity of stained target bacteria on the microspheres. We demonstrate that the functionalized alginate microspheres yield specificity comparable with an enzyme-linked immunosorbent assay. The high surface area-to-volume ratio of the functionalized porous alginate microspheres improves the detection limit. By using the droplet microfluidics, we can easily modify the size and shape of alginate microspheres, and increase the concentration of functionalized alginate microspheres to further enhance binding kinetics and enable multiplexing. PMID:23966617

  11. Microfluidic one-step synthesis of alginate microspheres immobilized with antibodies.

    PubMed

    Chen, Wanyu; Kim, Jong-Hoon; Zhang, Di; Lee, Kyong-Hoon; Cangelosi, G A; Soelberg, S D; Furlong, C E; Chung, Jae-Hyun; Shen, Amy Q

    2013-11-01

    Micrometre- and submicrometre-size functionalized beads are frequently used to capture targets of interest from a biological sample for biological characterizations and disease diagnosis. The main challenge of the microbead-based assay is in the immobilization of probe molecules onto the microbead surfaces. In this paper, we report a versatile droplet microfluidics method to fabricate alginate microspheres while simultaneously immobilizing anti-Mycobacterium tuberculosis complex IgY and anti-Escherichia coli IgG antibodies primarily on the porous alginate carriers for specific binding and binding affinity tests. The binding affinity of antibodies is directly measured by fluorescence intensity of stained target bacteria on the microspheres. We demonstrate that the functionalized alginate microspheres yield specificity comparable with an enzyme-linked immunosorbent assay. The high surface area-to-volume ratio of the functionalized porous alginate microspheres improves the detection limit. By using the droplet microfluidics, we can easily modify the size and shape of alginate microspheres, and increase the concentration of functionalized alginate microspheres to further enhance binding kinetics and enable multiplexing.

  12. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  13. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  14. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  15. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  16. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  17. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  18. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    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. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  19. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  20. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  1. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  2. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2010 CFR

    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. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

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

    PubMed

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

    2016-05-01

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

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

    PubMed

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

    2016-05-01

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

  5. Microbial alginate production, modification and its applications

    PubMed Central

    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

  6. Sodium Alginate with PEG/PEO Blends as a Floating Drug Delivery Carrier – In vitro Evaluation

    PubMed Central

    Mary, Christe Sonia; Swamiappan, Sasikumar

    2016-01-01

    Purpose: Floating drug delivery system reduces the quantity of drug intake and the risk of overloading the organs with excess drug. Methods: In the present study, we prepared the blends of sodium alginate with polyethylene glycol (PEG) and polyethylene oxide (PEO) as a matrix, sodium hydrogen carbonate as a pore forming agent, methyl cellulose as a binder and barium chloride containing 10% acetic acid as a hardening agent. Different ratios of pore forming agent to the polymer blend was used to prepare the floating beads with different porosity and morphology. Ciprofloxacin hydrochloride was used as a model drug for the release kinetics studies. Results: The beads were characterized by optical and FESEM microscopy to study the morphology and pore dimensions. The results obtained shows decrease in beads size with increase in the concentration of the pore forming agent. The swelling properties of the beads were found to be in the range of 80% to 125%. The release kinetics of the ciprofloxacin from the beads was measured by UV-Visible spectroscopy at λmax of 278nm and the results shows for highly porous beads. Conclusion: By varying the amount of alginate and pore forming agent the release kinetics is found to get altered. As a result, ciprofloxacin hydrochloride release is found to be sustained from the blended beads. PMID:27766228

  7. Montmorillonite-alginate nanocomposite as a drug delivery system--incorporation and in vitro release of irinotecan.

    PubMed

    Iliescu, Ruxandra Irina; Andronescu, Ecaterina; Ghitulica, Cristina Daniela; Voicu, Georgeta; Ficai, Anton; Hoteteu, Mihai

    2014-03-25

    The scope of the present study was the preparation and characterization of irinotecan nanocomposite beads based on montmorillonite (Mt) and sodium alginate (AL) as drug carriers. After irinotecan (I) incorporation into Mt, the resulting hybrid was compounded with alginate, and I-Mt-AL nanocomposite beads were obtained by ionotropic gelation technique. The structure and surface morphology of the hybrid and composite materials were established by means of X-ray diffraction (XRD), IR spectroscopy (FT-IR), thermal analysis (TG-DTA) and scanning electron microscopy (SEM). Irinotecan incorporation efficiency in Mt and in alginate beads was determined both by UV-vis spectroscopy and thermal analysis and was found to be high. The hybrid and composite materials were tested in vitro in simulated intestinal fluid (pH 7.4, at 37 °C) in order to establish if upon administering the beads at the site of a resected colorectal tumor, the delivery of the drug is sustained and can represent an alternative to the existing systemic chemotherapy. The in vitro drug release test results clearly suggested that Mt, and Mt along with AL were able to control the release of irinotecan by making it sustained, without any burst effect, and by reducing the released amount and the release rate. The nanocomposite beads may be a promising drug delivery system in chemotherapy. PMID:23998956

  8. Detoxification of Hg(II) from aqueous and enzyme media: Pristine vs. tailored calcium alginate hydrogels.

    PubMed

    Sarkar, Kangkana; Ansari, Zarina; Sen, Kamalika

    2016-10-01

    Calcium alginate (CA) hydrogels were tailored using phenolic compounds (PC) like, thymol, morin, catechin, hesperidin, during their preparation. The PC incorporated gels show modified surface features as indicated by scanning electron microscopic images (SEM). The rheological studies show that excepting the hesperidin incorporated gels all the other kinds including calcium alginate pristine have similar mechanical strength. The hesperidine incorporated CA gels had the maximum capacity to adsorb Hg. The Freundlich adsorption isotherms show higher values of adsorption capacity for all PC incorporated CA beads than the pristine CA (PCA). The hesperidin incorporated CA gels were found to show the best adsorption condition at neutral pH and an optimum contact time of 2.5h at 25°C. Considering the possibility of ingested Hg detoxification from human alimentary tract, the hesperidin and morin incorporated CA beads were further modified through incorporation of cod liver oil as the digestion time of fat in stomach is higher. In vitro uptake capacities of Hg in pepsin and pancreatin containing enzyme media were studied with hesperidin and morin incorporated beads and their corresponding fat incorporated beads also. In the pepsin medium, there was no uptake by hesperidin and fat-hesperidin incorporated beads, which is possibly due to the higher acidity of the medium. But in pancreatin medium Hg was taken up by both kinds of beads. Morin and morin-fat incorporated beads were efficient to uptake Hg from both the pepsin and pancreatin medium. The tailored CA beads may therefore serve as efficient scaffolds to rescue Hg ingested individuals. PMID:27208797

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

    PubMed Central

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

    2016-01-01

    Probiotic microorganisms are incorporated into a wide variety of foods, supplements, and pharmaceuticals to promote human health and wellness. However, maintaining bacterial cell viability during storage and gastrointestinal transit remains a challenge. Encapsulation of bifidobacteria within food-grade hydrogel particles potentially mitigates their sensitivity to environmental stresses. In this study, Bifidobacterium longum subspecies and strains were encapsulated in core-shell microgels consisting of an alginate core and a microgel shell. Encapsulated obligate anaerobes Bifidobacterium longum subsp. infantis and Bifidobacterium longum subsp. longum exhibited differences in viability in a strain-dependent manner, without a discernable relationship to subspecies lineage. This includes viability under aerobic storage conditions and modeled gastrointestinal tract conditions. Coating alginate microgels with chitosan did not improve viability compared to cells encapsulated in alginate microgels alone, suggesting that modifying the surface charge alone does not enhance delivery. Thus hydrogel beads have great potential for improving the stability and efficacy of bifidobacterial probiotics in various nutritional interventions. PMID:27148184

  10. Designing a highly efficient chemical chaperone system using chitosan-coated alginate.

    PubMed

    Khodagholi, Fariba; Farahmand, Shahrzad; Tusi, Solaleh Khoramian

    2010-07-01

    In the present work we prepared chitosan-coated alginate beads, to use as a chemical chaperone based on the electrostatic interaction between the carboxylate groups of alginate and the ammonium groups of chitosan. This procedure was an attempt for designing a highly efficient chemical chaperone to improve protein stability and refolding. Based on enzyme recovered activity, turbidity, far-UV CD and fluorescence data, alkaline phosphatase can be stabilized and refolded to a higher degree in the presence of alginate capsules compared with unassisted form and was further improved by including chitosan. Finally the maximum yield was obtained when the refolding process was achieved under a well worked out temperature program: incubation of the captured-enzyme for 20 min at 4 degrees C followed by overnight incubation at 22 degrees C, which showed that aggregation is a major limitation to refolding.

  11. Bead-Dazzled Baskets.

    ERIC Educational Resources Information Center

    St. Clair, Sharon

    2002-01-01

    Presents an art lesson used when teaching about North American Indians to fourth- and fifth-grade students. Explains that the students learn how to make baskets using a coil-wrap technique with colored yarns and beads. Provides a step-by-step explanation of how to create the baskets. (CMK)

  12. Pulsating bead-based assay.

    PubMed

    Thompson, Jason A; Bau, Haim H

    2011-04-15

    In recent years, there has been a growing interest in using porous microbeads such as agarose beads as solid supports to bind target molecules from complex fluid samples. Porous beads have large surface area to volume ratios and high receptor concentrations, and they facilitate relatively high sensitivity detection and multiplexing. Unfortunately, to take full advantage of the porous beads' attributes, long incubation times are needed due to the relatively slow mass transfer of target molecules from the exterior solution into the beads' interior. To accelerate the mass transfer process, we propose a novel assay in which functionalized porous beads are periodically compressed and expanded. Preliminary experiments were carried out to compare the performance of the pulsating beads with that of conventional, nonpulsating beads. These experiments indicate that the pulsating beads significantly accelerate binding rates with minimal increase in nonspecific binding. Thus, pulsing has the potential of significantly reducing assay time.

  13. Alginate: properties and biomedical applications

    PubMed Central

    Lee, Kuen Yong; Mooney, David J.

    2011-01-01

    Alginate is a biomaterial that has found numerous applications in biomedical science and engineering due to its favorable properties, including biocompatibility and ease of gelation. Alginate hydrogels have been particularly attractive in wound healing, drug delivery, and tissue engineering applications to date, as these gels retain structural similarity to the extracellular matrices in tissues and can be manipulated to play several critical roles. This review will provide a comprehensive overview of general properties of alginate and its hydrogels, their biomedical applications, and suggest new perspectives for future studies with these polymers. PMID:22125349

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

    PubMed

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

    2010-10-01

    Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen that is required for the biochemical oxidation of the organic compounds in 5 days. New biosensor-based methods have been conducted for a faster determination of BOD. In this study, a mathematical model to evaluate the feasibility of using a BOD sensor, based on disposable alginate-entrapped bacteria, for monitoring BOD in situ was applied. The model considers the influences of alginate bead size and bacterial concentration. The disposable biosensor can be adapted according to specific requirements depending on the organic load contained in the wastewater. Using Klein and Washausen parameter in a Lineweaver-Burk plot, the glucose diffusivity was calculated in 6.4 × 10(-10) (m2/s) for beads of 1 mm in diameter and slight diffusion restrictions were observed (n = 0.85). Experimental results showed a correlation (p < 0.05) between the respirometric peak and the standard BOD test. The biosensor response was representative of BOD.

  15. Quantum dot-encoded mesoporous beads with high brightness and uniformity: rapid readout using flow cytometry.

    PubMed

    Gao, Xiaohu; Nie, Shuming

    2004-04-15

    A new generation of optically encoded beads has been prepared by using mesoporous polystyrene beads and surfactant-coated semiconductor quantum dots. In comparison with nonporous beads of similar sizes and chemical compositions, the encoded porous beads are approximately 1000 times brighter and 5 times more uniform in fluorescence intensities. Using both absolute intensity and ratiometric fluorescence coding, we show that the beads can be identified with a standard flow cytometer at 1000 beads/s. This result indicates that the multiple excited-state lifetimes and relaxation pathways of quantum dots do not limit their applications in high-speed optical detection and imaging.

  16. Formulation of nano-zinc oxide into biocomposite beads for dye decolorization

    NASA Astrophysics Data System (ADS)

    Elkady, M. F.; Hassan, H. Shokry; El-Shazly, A. H.

    2015-03-01

    Zinc oxide nano-powder was prepared using sol-gel technique to be encapsulated onto polymeric blend composed from alginate and polyvinyl alcohol to fabricate novel bio-composite beads of nano-zinc oxide. The XRD patterns of both zinc oxide nano-powder and its polymeric hybrid were crystalline in their nature. The FTIR analysis of the fabricated ZnO polymeric hybrid confirms the binding between zinc oxide and the polymeric matrix. The BET analysis demonstrated that the calculated specific surface area of the formulated ZnO beads that equal to 22.8 m2/g is comparatively less than that of the free ZnO nano-powdered that equivalent to 64.9 m2/g. The thermal stability of ZnO nano-powdered dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500rpm. Moreover, this hybrid beads are chemically stable at the acidic media. The formulated ZnO hybrid beads verified to be good adsorbent material for C.I basic blue 41 (CB41).

  17. The Bactericidal Effect of Dendritic Copper Microparticles, Contained in an Alginate Matrix, on Escherichia coli

    PubMed Central

    Thomas, Simon F.; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel; Mason, Paul T.; Allen, Michael J.

    2014-01-01

    Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 106 cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 108 cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM) of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate. PMID:24831035

  18. Single-step laser-based fabrication and patterning of cell-encapsulated alginate microbeads

    PubMed Central

    Kingsley, DM; Dias, AD; Chrisey, DB; Corr, DT

    2014-01-01

    Alginate can be used to encapsulate mammalian cells and for the slow release of small molecules. Packaging alginate as microbead structures allows customizable delivery for tissue engineering, drug release, or contrast agents for imaging. However, state-of-the-art microbead fabrication has limited range in achievable bead sizes, and poor control over bead placement, which may be desired to localize cellular signaling or delivery. Herein, we present a novel, laser-based method for single-step fabrication and precise planar placement of alginate microbeads. Our results show that bead size is controllable within 8%, and fabricated microbeads can remain immobilized within 2% of their target placement. Demonstration of this technique using human breast cancer cells shows that cells encapsulated within these microbeads survive at a rate of 89.6%, decreasing to 84.3% after five days in culture. Infusing rhodamine dye into microbeads prior to fluorescent microscopy shows their 3D spheroidal geometry and the ability to sequester small molecules. Microbead fabrication and patterning is compatible with conventional cellular transfer and patterning by laser direct-write, allowing location-based cellular studies. While this method can also be used to fabricate microbeads en masse for collection, the greatest value to tissue engineering and drug delivery studies and applications lies in the pattern registry of printed microbeads. PMID:24192221

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

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    diabetic mice. To achieve these aims, extensive physicochemical analyses of the alginates and microcapsules were carried out. Among the properties of the alginates that were investigated include their purity (LAL assay, microBCA), chemical composition (nuclear magnetic resonance, NMR), elemental composition (x-ray photoelectron spectroscopy, XPS), and hydrophilicity (contact angle technique). As for the microcapsules, we also examined their surface chemical composition (XPS), hydrophilicity, as well as alginate-polycation interactions (Fourier transform infrared spectroscopy, FTIR), and membrane strength (osmotic swelling). The results of this research led to a number of important conclusions about the biocompatibility of alginates and alginate-based microcapsules. First of all, purifying an alginate does not guarantee its biocompatibility. Indeed, we provided evidence that both the alginate chemical composition (i.e. relative content of mannuronate and guluronate) and its intrinsic viscosity influence the extent of host cell adhesion to alginate gel beads. Using a biocompatible alginate, we then provided evidence that microcapsule biocompatibility is greatly compromised by its polycationic membrane. We showed that this membrane is responsible for the adsorption of opsonizing proteins in vitro and the adhesion of immune cells in vivo. That said, the severity of inflammatory response to the membrane can vary, and this depended on the microcapsule design, including the choice of alginate and polycation type. Results of our physicochemical analyses suggested that the most important factor determining biocompatibility is the ability of the polycation to diffuse into, and subsequently bind to, the alginate gel core. Moreover, adding a final coating of alginate had no significant effect on reversing the effects of the membrane on various microcapsule properties (surface composition, hydrophobicity, stability), nor did this coating reduce its immunogenicity. Although we

  20. Beaded streams of Arctic permafrost landscapes

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

    2014-07-01

    Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s-1, yet channel runs still move water rapidly between pools

  1. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  2. Bead lightning formation

    SciTech Connect

    Ludwig, G.O.; Saba, M.M.F.

    2005-09-15

    Formation of beaded structures in triggered lightning discharges is considered in the framework of both magnetohydrodynamic (MHD) and hydrodynamic instabilities. It is shown that the space periodicity of the structures can be explained in terms of the kink and sausage type instabilities in a cylindrical discharge with anomalous viscosity. In particular, the fast growth rate of the hydrodynamic Rayleigh-Taylor instability, which is driven by the backflow of air into the channel of the decaying return stroke, dominates the initial evolution of perturbations during the decay of the return current. This instability is responsible for a significant enhancement of the anomalous viscosity above the classical level. Eventually, the damping introduced at the current channel edge by the high level of anomalous viscous stresses defines the final length scale of bead lightning. Later, during the continuing current stage of the lightning flash, the MHD pinch instability persists, although with a much smaller growth rate that can be enhanced in a M-component event. The combined effect of these instabilities may explain various aspects of bead lightning.

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

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    diabetic mice. To achieve these aims, extensive physicochemical analyses of the alginates and microcapsules were carried out. Among the properties of the alginates that were investigated include their purity (LAL assay, microBCA), chemical composition (nuclear magnetic resonance, NMR), elemental composition (x-ray photoelectron spectroscopy, XPS), and hydrophilicity (contact angle technique). As for the microcapsules, we also examined their surface chemical composition (XPS), hydrophilicity, as well as alginate-polycation interactions (Fourier transform infrared spectroscopy, FTIR), and membrane strength (osmotic swelling). The results of this research led to a number of important conclusions about the biocompatibility of alginates and alginate-based microcapsules. First of all, purifying an alginate does not guarantee its biocompatibility. Indeed, we provided evidence that both the alginate chemical composition (i.e. relative content of mannuronate and guluronate) and its intrinsic viscosity influence the extent of host cell adhesion to alginate gel beads. Using a biocompatible alginate, we then provided evidence that microcapsule biocompatibility is greatly compromised by its polycationic membrane. We showed that this membrane is responsible for the adsorption of opsonizing proteins in vitro and the adhesion of immune cells in vivo. That said, the severity of inflammatory response to the membrane can vary, and this depended on the microcapsule design, including the choice of alginate and polycation type. Results of our physicochemical analyses suggested that the most important factor determining biocompatibility is the ability of the polycation to diffuse into, and subsequently bind to, the alginate gel core. Moreover, adding a final coating of alginate had no significant effect on reversing the effects of the membrane on various microcapsule properties (surface composition, hydrophobicity, stability), nor did this coating reduce its immunogenicity. Although we

  4. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  5. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  6. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  7. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  8. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  9. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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...

  10. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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...

  11. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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...

  12. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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...

  13. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    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...

  14. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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...

  15. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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...

  16. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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...

  17. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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...

  18. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2010 CFR

    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...

  19. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1011 Alginic acid. (a) Alginic acid is a colloidal, hydrophilic polysaccharide obtained from...

  20. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  1. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  2. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  3. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  4. 21 CFR 582.7133 - Ammonium alginate.

    Code of Federal Regulations, 2010 CFR

    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...

  5. 21 CFR 582.7133 - Ammonium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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...

  6. Nonlinear elasticity of alginate gels

    NASA Astrophysics Data System (ADS)

    Hashemnejad, Seyed Meysam; Kundu, Santanu

    Alginate is a naturally occurring anionic polysaccharide extracted from brown algae. Because of biocompatibility, low toxicity, and simple gelation process, alginate gels are used in biomedical and food applications. Here, we report the rheological behavior of ionically crosslinked alginate gels, which are obtained by in situ gelation of alginates with calcium salts, in between two parallel plates of a rheometer. Strain stiffening behavior was captured using large amplitude oscillatory shear (LAOS) experiments. In addition, negative normal stress was observed for these gels, which has not been reported earlier for any polysaccharide networks. The magnitude of negative normal stress increases with applied strain and can exceed that of the shear stress at large strain. Rheological results fitted with a constitutive model that considers both stretching and bending of chains indicate that nonlinearity is likely related to the stretching of the chains between the crosslink junctions. The results provide an improved understanding of the deformation mechanism of ionically crosslinked alginate gel and the results will be important in developing synthetic extracellular matrix (ECM) from these materials.

  7. Beads in the Tooth

    PubMed Central

    Srinivasan, Ila

    2011-01-01

    Foreign objects in a tooth are often diagnosed accidentally. A detailed case history, clinical and radiographic examinations are necessary to know the exact nature, size, location of the foreign body and the difficulty involved in its retrieval. In the present case, two beads, one radiopaque and one radiolucent were found in the same tooth at different places of 11-year-old girl. Patient did not reveal proper history out of fear. Both the foreign objects were discovered during routine endodontic procedure which were removed following simple clinical procedure causing minimal damage to the internal tooth structure.

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

    PubMed Central

    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

  9. Sustained release of vascular endothelial growth factor from calcium-induced alginate hydrogels reinforced by heparin and chitosan.

    PubMed

    Lee, K W; Yoon, J J; Lee, J H; Kim, S Y; Jung, H J; Kim, S J; Joh, J W; Lee, H H; Lee, D S; Lee, S K

    2004-10-01

    A possible alternative for immunosuppression is a microencapsulation technique using hydrogels, which have been utilized for cell immobilization and drug delivery systems. Angiogenesis is crucial for delivery of the metabolic products to the host tissues as well as to supply oxygen and nutrients to cells. The local delivery of angiogenic growth factors, such as VEGF and basic FGF, has been recently studied to enhance angiogenesis on peripheral tissue of graft. In this study, we evaluated sustained VEGF release with a model using hydrogels coated with chitosan and heparin in vitro. We fabricated calcium alginate gels and chitosan-coated calcium alginate gels. Heparinized chitosan-coated calcium-induced alginate hydrogel beads were prepared by soaking chitosan-coated calcium alginate gels in heparin solution. We compared the stability and VEGF release manner between three kinds of hydrogels. To compare the stability, 5 mL of each hydrogel was incubated with 20 mL PBS under the rotational culture. Compression forces were measured using a rheometer. The amount of VEGF released from the gels was measured by ELISA. The heparin-coated chitosan alginate hydrogels showed the highest surface stability among the three hydrogels. VEGF from the heparinized gel was released in sustained manner up to 10 days in vitro. Chitosan-coated alginate gels released 90% of loaded VEGF within 5 days. These results suggest that local delivery of VEGF using a heparinized hydrogel may provide a long-term supply of angiogenic growth factor that might induce new vessel formation in vivo.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

    Carqueja (Pterospartum tridentatum) is an endemic species and various bioactive compounds have been identified in its aqueous extract. The aim of this study was to protect the natural antioxidants from the aqueous extract of carqueja by encapsulation in Ca-alginate microbeads and Ca-alginate microbeads containing 10% and 20% (w/v) of inulin. The microbeads produced by electrostatic extrusion technique had an average diameter from 625 μm to 830 μm depending on the portion of inulin. The sphericity factor of the hydrogel microbeads had values between 0.014 and 0.026, while freeze dried microbeads had irregular shape, especially those with no excipient. The reduction in microbeads size after freeze drying process (expressed as shrinkage factor) ranged from 0.338 (alginate microbeads with 20% (w/v) of inulin) to 0.523 (plain alginate microbeads). The expressed radical scavenging activity against ABTS and DPPH radicals was found to be between 30% and 40% for encapsulated extract, while the fresh extract showed around 47% and 57% of radical scavenging activity for ABTS and DPPH radicals, respectively. The correlation between antioxidant activity and the total phenolic content were found to be positive (in both assay methods, DPPH and ABTS), which indicate that the addition of inulin didn't have influence on antioxidant activity. The presence of inulin reduced stiffness of the hydrogel, and protected bead structure from collapse upon freeze-drying. Alginate-inulin beads are envisaged to be used for delivery of aqueous P. tridentatum extract in functional food products. PMID:26613390

  12. The heart beads program.

    PubMed

    Dengler, Kate Alexa; Scarfe, Gabbie; Redshaw, Sarah; Wilson, Valerie

    2011-01-01

    From July 2008 through June 2009, 760 infants and children with cardiac conditions were admitted to a pediatric hospital in Australia with approximately 360 cardiac surgical procedures performed.This was the first experience in hospital for many of these children, with diagnoses signaling the beginning of a long and arduous journey. These children undergo multiple treatments and procedures,as well as multiple admissions for further surgeries. Procedures in any regard can cause stress and anxiety, especially in children who often have limited understanding and so little control over what happens to them (Lau, 2002).A heart center for children exists at the hospital with the aim of providing a consistent experience for children with cardiac conditions as they move through the different hospital environments, from preadmission clinic to operating theaters to the pediatric intensive care unit (PICU), and then on to the cardiac ward. The Heart Beads Program was developed within a context of person-centered care to enrich the experience of children with cardiac conditions by providing them with distinctive beads specific to each procedure, treatment, or event in recognition of their experiences and endurance (McCormack et al., 2008). This column focuses on the process of starting the program and on preliminary responses from staff, children, and families.

  13. Patterning surface by site selective capture of biopolymer hydrogel beads.

    PubMed

    Guyomard-Lack, Aurélie; Moreau, Céline; Delorme, Nicolas; Marquis, Mélanie; Fang, Aiping; Bardeau, Jean-François; Cathala, Bernard

    2012-06-01

    This communication describes the fabrication of microstructured biopolymer surfaces by the site-selective capture of pectin hydrogel beads. A positively charged surface consisting of poly-L-lysine (PLL) was subjected to site-selective enzymatic degradation using patterned polydimethylsiloxane (PDMS) stamps covalently modified with trypsin, according to the recently described method. The patterned surface was used to capture ionically cross-linked pectin beads. The desired patterning of the hydrogel surfaces was generated by site-selective immobilization of these pectin beads. The ability of the hydrogels to be dried and swollen in water was assessed.

  14. Patterning surface by site selective capture of biopolymer hydrogel beads.

    PubMed

    Guyomard-Lack, Aurélie; Moreau, Céline; Delorme, Nicolas; Marquis, Mélanie; Fang, Aiping; Bardeau, Jean-François; Cathala, Bernard

    2012-06-01

    This communication describes the fabrication of microstructured biopolymer surfaces by the site-selective capture of pectin hydrogel beads. A positively charged surface consisting of poly-L-lysine (PLL) was subjected to site-selective enzymatic degradation using patterned polydimethylsiloxane (PDMS) stamps covalently modified with trypsin, according to the recently described method. The patterned surface was used to capture ionically cross-linked pectin beads. The desired patterning of the hydrogel surfaces was generated by site-selective immobilization of these pectin beads. The ability of the hydrogels to be dried and swollen in water was assessed. PMID:22326339

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

    PubMed

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

    2013-07-01

    The majority of cell encapsulation systems applied so far are based on polyelectrolyte complexes of alginate and polyvalent metal cations. Although widely used, these systems suffer from the risk of disintegration. This can be partially solved by applying chitosan as additional outer membrane. However, chitosan can be dissolved in water only at a low pH, which limits its use in the field of bioencapsulation. In this study, novel primary and tertiary amine chitosan derivatives have been synthesized, which may be dissolved at pH 7.0, and retain the ability to effectively form additional membrane on the surface of alginate beads. As aqueous solutions tertiary amines dimethylamino-1-propyl-chitosan and dimethylethylamine-chitosan with linear hydrochloride aliphatic chains had the lowest toxicity, whereas dimethylpropylamine-chitosan, diethylaminoethyl-chitosan, and diisopropylaminoethyl-chitosan with branched hydrochloride aliphatic were cytotoxic to the majority of tested cells. When applied as polyelectrolyte complexation agent on the surface of alginate beads, none of the derivates had any negative effect on the metabolic activity of encapsulated beta-cells. PMID:23203606

  16. Photocatalytic degradation of pharmaceutical wastes by alginate supported TiO2 nanoparticles in packed bed photo reactor (PBPR).

    PubMed

    Sarkar, Santanu; Chakraborty, Sudip; Bhattacharjee, Chiranjib

    2015-11-01

    In recent years deposal of pharmaceutical wastes has become a major problem globally. Therefore, it is necessary to removes pharmaceutical waste from the municipal as well as industrial effluents before its discharge. The convectional wastewater and biological treatments are generally failed to separate different drugs from wastewater streams. Thus, heterogeneous photocatalysis process becomes lucrative method for reduction of detrimental effects of pharmaceutical compounds. The main disadvantage of the process is the reuse or recycle of photocatalysis is a tedious job. In this work, the degradation of aqueous solution of chlorhexidine digluconate (CHD), an antibiotic drug, by heterogeneous photocatalysis was study using supported TiO2 nanoparticle. The major concern of this study is to bring down the limitations of suspension mode heterogeneous photocatalysis by implementation of immobilized TiO2 with help of calcium alginate beads. The alginate supported catalyst beads was characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDAX) as well as the characteristic crystalline forms of TiO2 nanoparticle was confirmed by XRD. The degradation efficiency of TiO2 impregnated alginate beads (TIAB) was compared with the performance of free TiO2 suspension. Although, the degradation efficiency was reduced considerably using TIAB but the recycle and reuse of catalyst was increased quite appreciably. The kinetic parameters related to this work have also been measure. Moreover, to study the susceptibility of the present system photocatalysis of other three drugs ibuprofen (IBP), atenolol (ATL) and carbamazepine (CBZ) has been carried out using immobilized TiO2. The continuous mode operation in PBPR has ensured the applicability of alginate beads along with TiO2 in wastewater treatment. The variation of residence time has significant impact on the performance of PBPR. PMID:25743764

  17. Photocatalytic degradation of pharmaceutical wastes by alginate supported TiO2 nanoparticles in packed bed photo reactor (PBPR).

    PubMed

    Sarkar, Santanu; Chakraborty, Sudip; Bhattacharjee, Chiranjib

    2015-11-01

    In recent years deposal of pharmaceutical wastes has become a major problem globally. Therefore, it is necessary to removes pharmaceutical waste from the municipal as well as industrial effluents before its discharge. The convectional wastewater and biological treatments are generally failed to separate different drugs from wastewater streams. Thus, heterogeneous photocatalysis process becomes lucrative method for reduction of detrimental effects of pharmaceutical compounds. The main disadvantage of the process is the reuse or recycle of photocatalysis is a tedious job. In this work, the degradation of aqueous solution of chlorhexidine digluconate (CHD), an antibiotic drug, by heterogeneous photocatalysis was study using supported TiO2 nanoparticle. The major concern of this study is to bring down the limitations of suspension mode heterogeneous photocatalysis by implementation of immobilized TiO2 with help of calcium alginate beads. The alginate supported catalyst beads was characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDAX) as well as the characteristic crystalline forms of TiO2 nanoparticle was confirmed by XRD. The degradation efficiency of TiO2 impregnated alginate beads (TIAB) was compared with the performance of free TiO2 suspension. Although, the degradation efficiency was reduced considerably using TIAB but the recycle and reuse of catalyst was increased quite appreciably. The kinetic parameters related to this work have also been measure. Moreover, to study the susceptibility of the present system photocatalysis of other three drugs ibuprofen (IBP), atenolol (ATL) and carbamazepine (CBZ) has been carried out using immobilized TiO2. The continuous mode operation in PBPR has ensured the applicability of alginate beads along with TiO2 in wastewater treatment. The variation of residence time has significant impact on the performance of PBPR.

  18. Adsorption and desorption of Zn(II) and Cu(II) on Ca- alginate immobilized activated rice bran

    NASA Astrophysics Data System (ADS)

    Suratman, A.; Kamalia, N. Z.; Kusumawati, W. A.

    2016-02-01

    Ca-alginate immobilized activated rice bran has been used for adsorption of Zn(II) and Cu(II) from aqueous solution. The effect of the pH, kinetics model, adsorption isotherm and desorption on the adsorption performance was investigated. Activated rice bran was immobilized by the entrapment in alginate beads. The adsorption strength of Ca-alginate immobilized activated rice bran was compared to Ca-alginate and non-immobilized activated rice bran. The concentrations of adsorbed ions were analyzed using Atomic Absorption Spectrophotometer (AAS). The result showed that pH of 4.0 and the contact time of 120 min are the optimum condition for adsorption of Zn(II) and Cu(II). The adsorption kinetic of Zn(II) and Cu(II) followed the pseudo-second-order model with adsorption rate constant 4.9 x 10-2 and 3.14 g.mg-1.min-1, respectively. The both adsorption processes obeyed Langmuir isotherm with adsorption capacity of 2.03 and 2.42 mg.g-1 of adsorbent, respectively. The strength of Zn adsorption on Ca-alginate immobilized activated rice bran (86.63%) was more effective compared to Ca-alginate beads (60.96%) and activated rice bran (43.85%). The strength of Cu adsorption was 80.00%, 61.50% and 22.10%, respectively. The desorption of Zn(II) and Cu(II) showed that recovery percentage of the adsorption was 76.56% and 57.80% with the condition of using HCl 0.1 M as desorption agent for 1 hour.

  19. Degradation of complex carbohydrate: immobilization of pectinase from Bacillus licheniformis KIBGE-IB21 using calcium alginate as a support.

    PubMed

    Rehman, Haneef Ur; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio; Ansari, Asma

    2013-08-15

    Pectinases are heterogeneous group of enzymes that catalyse the hydrolysis of pectin substances which is responsible for the turbidity and undesirable cloudiness in fruits juices. In current study, partially purified pectinase from Bacillus licheniformis KIBGE-IB21 was immobilized in calcium alginate beads. The effect of sodium alginate and calcium chloride concentration on immobilization was studied and it was found that the optimal sodium alginate and calcium chloride concentration was 3.0% and 0.2 M, respectively. It was found that immobilization increases the optimal reaction time for pectin degradation from 5 to 10 min and temperature from 45 to 55°C, whereas, the optimal pH remained same with reference to free enzyme. Thermal stability of enzyme increased after immobilization and immobilized pectinase retained more than 80% of its initial activity after 5 days at 30°C as compared with free enzyme which showed only 30% of residual activity. The immobilized enzyme also exhibited good operational stability and 65% of its initial activity was observed during third cycle. In term of pectinase immobilization efficiency and stability, this calcium alginate beads approach seemed to permit good results and can be used to make a bioreactor for various applications in food industries.

  20. Osteogenic behavior of alginate encapsulated bone marrow stromal cells: an in vitro study.

    PubMed

    Abbah, S A; Lu, W W; Chan, D; Cheung, K M C; Liu, W G; Zhao, F; Li, Z Y; Leong, J C Y; Luk, K D K

    2008-05-01

    Sodium alginate is a useful polymer for the encapsulation and immobilization of a variety of cells in tissue engineering because it is biocompatible, biodegradable and easy to process into injectable microbeads. Despite these properties, little is known of the efficacy of calcium cross-linked alginate gel beads as a biodegradable scaffold for osteogenic cell proliferation and differentiation. In this study, we investigated the ability of rabbit derived bone marrow cells (BMCs) to proliferate and differentiate in alginate microbeads and compared them with BMCs cultured in poly-L-lysine (PLL) coated microbeads and on conventional 2D plastic surfaces. Results show that levels of proliferation and differentiation in microbeads and on tissue culture plastics were comparable. Cell proliferation in microbeads however diminished after fortification with a coating layer of PLL. Maximum cell numbers observed were, 3.32 x 10(5) +/- 1.72 x 103; 3.11 x 10(5) +/- 1.52 x 10(3) and 3.28 x 10(5) +/- 1.21 x 10(3 ) for the uncoated, PLL coated and plastic surface groups respectively. Alkaline phosphatase and protein expressions reflected the stage of cell differentiation. We conclude that calcium cross-linked alginate microbeads can act as a scaffold for BMC proliferation and osteogenic differentiation and has potential for use as 3D degradable scaffold.

  1. Survival of and wheat-root colonization by alginate encapsulated Herbaspirillum spp.

    PubMed

    el-Komy, H M

    2001-01-01

    The survival of Herbaspirillum spp. cells added directly or encapsulated in alginate beads and colonization of wheat roots was evaluated in soil microcosms. Cells entrapped in alginate in the presence of JNFb-broth and introduced into unplanted non-sterile clay loamy and sandy soils survived better than cells added directly to the same soils after 50 d incubation. On amendment by JNFb broth and/or skim milk the entrapped cells survived better than those prepared in water. Encapsulated cells survived better in a heavier textured soil (clay-loamy) than in a lighter (sandy) soil. Wheat plants growing in microcosms inoculated with various bead types from day 0 to day 30 exhibited high levels of histosphere colonization, nitrogenase activity (in situ) measured by acetylene reduction assay, plant dry mass and total N content but no symptoms of mottled stripe disease were observed. Comparable results of growth criteria and nitrogenase activity, but relatively lower bacterial populations, were obtained with wheat grown for 45 d after the inoculant had been introduced into the soil with different bead types.

  2. Arsenate removal by layered double hydroxides embedded into spherical polymer beads: Batch and column studies.

    PubMed

    Nhat Ha, Ho Nguyen; Kim Phuong, Nguyen Thi; Boi An, Tran; Mai Tho, Nguyen Thi; Ngoc Thang, Tran; Quang Minh, Bui; Van Du, Cao

    2016-01-01

    In this study, the performance of poly(layered double hydroxides) [poly(LDHs)] beads as an adsorbent for arsenate removal from aqueous solution was investigated. The poly(LDHs) beads were prepared by immobilizing LDHs into spherical alginate/polyvinyl alcohol (PVA)-glutaraldehyde beads (spherical polymer beads). Batch adsorption studies were conducted to assess the effect of contact time, solution pH, initial arsenate concentrations and co-existing anions on arsenate removal performance. The potential reuse of these poly(LDHs) beads was also investigated. Approximately 79.1 to 91.2% of arsenic was removed from an arsenate solution (50 mg As L(-1)) by poly(LDHs). The adsorption data were well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, and the adsorption capacities of these poly(LDHs) beads at pH 8 were from 1.64 to 1.73 mg As g(-1), as calculated from the Langmuir adsorption isotherm. The adsorption ability of the poly(LDHs) beads decreased by approximately 5-6% after 5 adsorption-desorption cycles. Phosphates markedly decreased arsenate removal. The effect of co-existing anions on the adsorption capacity declined in the following order: HPO4 (2-) > HCO3 (-) > SO4 (2-) > Cl(-). A fixed-bed column study was conducted with real-life arsenic-containing water. The breakthrough time was found to be from 7 to 10 h. Under optimized conditions, the poly(LDHs) removed more than 82% of total arsenic. The results obtained in this study will be useful for further extending the adsorbents to the field scale or for designing pilot plants in future studies. From the viewpoint of environmental friendliness, the poly(LDHs) beads are a potential cost-effective adsorbent for arsenate removal in water treatment. PMID:26818806

  3. Arsenate removal by layered double hydroxides embedded into spherical polymer beads: Batch and column studies.

    PubMed

    Nhat Ha, Ho Nguyen; Kim Phuong, Nguyen Thi; Boi An, Tran; Mai Tho, Nguyen Thi; Ngoc Thang, Tran; Quang Minh, Bui; Van Du, Cao

    2016-01-01

    In this study, the performance of poly(layered double hydroxides) [poly(LDHs)] beads as an adsorbent for arsenate removal from aqueous solution was investigated. The poly(LDHs) beads were prepared by immobilizing LDHs into spherical alginate/polyvinyl alcohol (PVA)-glutaraldehyde beads (spherical polymer beads). Batch adsorption studies were conducted to assess the effect of contact time, solution pH, initial arsenate concentrations and co-existing anions on arsenate removal performance. The potential reuse of these poly(LDHs) beads was also investigated. Approximately 79.1 to 91.2% of arsenic was removed from an arsenate solution (50 mg As L(-1)) by poly(LDHs). The adsorption data were well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, and the adsorption capacities of these poly(LDHs) beads at pH 8 were from 1.64 to 1.73 mg As g(-1), as calculated from the Langmuir adsorption isotherm. The adsorption ability of the poly(LDHs) beads decreased by approximately 5-6% after 5 adsorption-desorption cycles. Phosphates markedly decreased arsenate removal. The effect of co-existing anions on the adsorption capacity declined in the following order: HPO4 (2-) > HCO3 (-) > SO4 (2-) > Cl(-). A fixed-bed column study was conducted with real-life arsenic-containing water. The breakthrough time was found to be from 7 to 10 h. Under optimized conditions, the poly(LDHs) removed more than 82% of total arsenic. The results obtained in this study will be useful for further extending the adsorbents to the field scale or for designing pilot plants in future studies. From the viewpoint of environmental friendliness, the poly(LDHs) beads are a potential cost-effective adsorbent for arsenate removal in water treatment.

  4. Effect of Alginate Concentration on Alginate-TiO2 Hydrogel for Lead Ion Removal

    NASA Astrophysics Data System (ADS)

    Teoh, W. T.; Saito, N.; Sato, K.

    2011-03-01

    Alginate-TiO2 hydrogel was investigated for lead ion (Pb(II)) removal. By immobilizing TiO2 powder onto an alginate biopolymer, it is possible to utilize the ion exchange properties of the alginate and the photoreducibility of TiO2 to recover Pb(II). However, these photocatalytic activities degrade the alginate biopolymer in addition to removing Pb(II). This study examines photolytic degradation of alginate-TiO2 hydrogels prepared with alginate concentrations of 1, 1.5, 2, and 2.5%w/v; the same amount (0.4%w/v) of TiO2 was added to each alginate solution. The alginate-TiO2 hydrogels were formed by dripping the alginate-TiO2 suspension into a 0.2 M calcium chloride solution. The samples were washed and dried and then photoirradiated. The samples with alginate concentrations of 1 and 1.5%w/v were depolymerized, whereas the surface morphology of the sample that prepared from the 2%w/v alginate solution remained unchanged. The samples prepared from 1.5, 2, and 2.5%w/v alginate solutions had Pb(II) uptakes of 24.0, 39.8, and 39.7 mg/g, respectively.

  5. Removal of selenite and chromate using iron(III)-doped alginate gels

    SciTech Connect

    Min, J.H.; Hering, J.G.

    1999-03-01

    Oxyanionic contaminants, specifically selenium and chromium(VI), were removed from solution by sorption onto gel beads formed by pretreating the biopolymer alginic acid with calcium and iron(III). The calcium-iron gel beads were found to be effective at removing selenium(IV) from solution. Chromium(VI) removal was less effective and the rate of sorption was slower than that of selenium(IV). At an initial selenium(IV) concentration of 400 {micro}g/L (5.1 {micro}M), up to approximately 94% removal of selenium from solution was achieved by a 120-hour equilibration with 20 calcium-iron beads (10 mg/L or 180 {micro}M total iron). Optimal selenium(IV) removal and stability of the calcium-iron beads were achieved at pH 4. Selenium(IV) sorption and kinetics data were comparable with those observed previously for arsenic(V). Selenium(IV) sorption data, as a function of dissolved concentration and iron content, were modeled. As calcium-iron beads became saturated, the extent of sorption of selenium(IV) or arsenic(V) was decreased by the presence of competing contaminant oxyanions or nonhazardous inorganic anions such as phosphate.

  6. Engineering alginate as bioink for bioprinting.

    PubMed

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

    2014-10-01

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

  7. Engineering alginate as bioink for bioprinting

    PubMed Central

    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

    2015-01-01

    Recent advances in 3D printing offer an excellent opportunity to address critical challenges faced by current tissue engineering approaches. Alginate hydrogels have been extensively utilized as bioinks for 3D 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, we prepared a collection of 30 different alginate hydrogels with varied oxidation percentages and concentrations to develop a bioink platform that can be applied to a multitude of tissue engineering applications. We 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 structure integrity of the lattice structures (except the highly degradable one) after 8 days in culture. This research lays a foundation for the development of alginate-based bioink for tissue-specific tissue engineering applications. PMID:24998183

  8. Apparatus and method for the production of gel beads containing a biocatalyst

    DOEpatents

    Scott, C.D.; Scott, T.C.; Davison, B.H.

    1998-01-27

    An apparatus and method are disclosed for the large-scale and continuous production of gel beads containing a biocatalyst. The apparatus is a columnar system based on the chemical cross-linking of hydrocolloidal gels that contain and immobilize a biocatalyst, the biocatalyst being a microorganism or an enzyme. Hydrocolloidal gels, such as alginate, carrageenan, and a mixture of bone gelatin and modified alginate, provide immobilization matrices that can be used to entrap and retain the biocatalyst while allowing effective contact with substrates and release of products. Such immobilized biocatalysts are generally formulated into small spheres or beads that have high concentrations of the biocatalyst within the gel matrix. The columnar system includes a gel dispersion nozzle submerged in a heated non-interacting liquid, typically an organic liquid, that is immiscible with water to allow efficient formation of spherical gel droplets, the non-interacting liquid having a specific gravity that is less than water so that the gel droplets will fall through the liquid by the force of gravity. The heated non-interacting liquid is in direct contact with a chilled upflowing non-interacting liquid that will provide sufficient residence time for the gel droplets as they fall through the liquid so that they will be cooled below the gelling temperature and form solid spheres. The upflowing non-interacting liquid is in direct contact with an upflowing temperature-controlled aqueous solution containing the necessary chemicals for cross-linking or fixing of the gel beads to add the necessary stability. The flow rates of the two liquid streams can be varied to control the proper residence time in each liquid section to accommodate the production of gel beads of differing settling velocities. A valve is provided for continuous removal of the stabilized gel beads from the bottom of the column. 1 fig.

  9. Apparatus and method for the production of gel beads containing a biocatalyst

    DOEpatents

    Scott, Charles D.; Scott, Timothy C.; Davison, Brian H.

    1998-01-01

    An apparatus and method for the large-scale and continuous production of gel beads containing a biocatalyst. The apparatus is a columnar system based on the chemical cross-linking of hydrocolloidal gels that contain and immobilize a biocatalyst, the biocatalyst being a microorganism or an enzyme. Hydrocolloidal gels, such as alginate, carrageenan, and a mixture of bone gelatin and modified alginate, provide immobilization matrices that can be used to entrap and retain the biocatalyst while allowing effective contact with substrates and release of products. Such immobilized biocatalysts are generally formulated into small spheres or beads that have high concentrations of the biocatalyst within the gel matrix. The columnar system includes a gel dispersion nozzle submerged in a heated non-interacting liquid, typically an organic liquid, that is immiscible with water to allow efficient formation of spherical gel droplets, the non-interacting liquid having a specific gravity that is less than water so that the gel droplets will fall through the liquid by the force of gravity. The heated non-interacting liquid is in direct contact with a chilled upflowing non-interacting liquid that will provide sufficient residence time for the gel droplets as they fall through the liquid so that they will be cooled below the gelling temperature and form solid spheres. The upflowing non-interacting liquid is in direct contact with an upflowing temperature-controlled aqueous solution containing the necessary chemicals for cross-linking or fixing of the gel beads to add the necessary stability. The flow rates of the two liquid streams can be varied to control the proper residence time in each liquid section to accommodate the production of gel beads of differing settling velocities. A valve is provided for continuous removal of the stabilized gel beads from the bottom of the column.

  10. Efficient removal of heavy metal ions with biopolymer template synthesized mesoporous titania beads of hundreds of micrometers size.

    PubMed

    Wu, Na; Wei, Huanhuan; Zhang, Lizhi

    2012-01-01

    We demonstrated that mesoporous titania beads of uniform size (about 450 μm) and high surface area could be synthesized via an alginate biopolymer template method. These mesoporous titania beads could efficiently remove Cr(VI), Cd(II), Cr(III), Cu(II), and Co(II) ions from simulated wastewater with a facile subsequent solid-liquid separation because of their large sizes. We chose Cr(VI) removal as the case study and found that each gram of these titania beads could remove 6.7 mg of Cr(VI) from simulated wastewater containing 8.0 mg·L(-1) of Cr(VI) at pH = 2.0. The Cr(VI) removal process was found to obey the Langmuir adsorption model and its kinetics followed pseudo-second-order rate equation. The Cr(VI) removal mechanism of titania beads might be attributed to the electrostatic adsorption of Cr(VI) ions in the form of negatively charged HCrO(4)(-) by positively charged TiO(2) beads, accompanying partial reduction of Cr(VI) to Cr(III) by the reductive surface hydroxyl groups on the titania beads. The used titania beads could be recovered with 0.1 mol·L(-1) of NaOH solution. This study provides a promising micro/nanostructured adsorbent with easy solid-liquid separation property for heavy metal ions removal. PMID:22129207

  11. Efficient removal of heavy metal ions with biopolymer template synthesized mesoporous titania beads of hundreds of micrometers size.

    PubMed

    Wu, Na; Wei, Huanhuan; Zhang, Lizhi

    2012-01-01

    We demonstrated that mesoporous titania beads of uniform size (about 450 μm) and high surface area could be synthesized via an alginate biopolymer template method. These mesoporous titania beads could efficiently remove Cr(VI), Cd(II), Cr(III), Cu(II), and Co(II) ions from simulated wastewater with a facile subsequent solid-liquid separation because of their large sizes. We chose Cr(VI) removal as the case study and found that each gram of these titania beads could remove 6.7 mg of Cr(VI) from simulated wastewater containing 8.0 mg·L(-1) of Cr(VI) at pH = 2.0. The Cr(VI) removal process was found to obey the Langmuir adsorption model and its kinetics followed pseudo-second-order rate equation. The Cr(VI) removal mechanism of titania beads might be attributed to the electrostatic adsorption of Cr(VI) ions in the form of negatively charged HCrO(4)(-) by positively charged TiO(2) beads, accompanying partial reduction of Cr(VI) to Cr(III) by the reductive surface hydroxyl groups on the titania beads. The used titania beads could be recovered with 0.1 mol·L(-1) of NaOH solution. This study provides a promising micro/nanostructured adsorbent with easy solid-liquid separation property for heavy metal ions removal.

  12. Effect of hydrogen in an argon GTAW shielding gas: Arc characteristics and bead morphology

    SciTech Connect

    Onsoeien, M.; Olson, D.L.; Liu, S. . Center for Welding and Joining Research); Peters, R. )

    1995-01-01

    The influence of hydrogen additions to an argon shielding gas on the heat input and weld bead morphology was investigated using the gas tungsten arc welding process. Variations in weld bead size and shape with hydrogen additions were related to changes in the ability of the arc to generate heat and not to generate perturbations in the weld pool caused by Marangoni fluid flow.

  13. Highly efficient, long life, reusable and robust photosynthetic hybrid core-shell beads for the sustainable production of high value compounds.

    PubMed

    Desmet, Jonathan; Meunier, Christophe; Danloy, Emeric; Duprez, Marie-Eve; Lox, Frédéric; Thomas, Diane; Hantson, Anne-Lise; Crine, Michel; Toye, Dominique; Rooke, Joanna; Su, Bao-Lian

    2015-06-15

    An efficient one-step process to synthesize highly porous (Ca-alginate-SiO2-polycation) shell: (Na-alginate-SiO2) core hybrid beads for cell encapsulation, yielding a reusable long-life photosynthetically active material for a sustainable manufacture of high-value metabolites is presented. Bead formation is based on crosslinking of an alginate biopolymer and mineralisation of silicic acid in combination with a coacervation process between a polycation and the silica sol, forming a semi-permeable external membrane. The excellent mechanical strength and durability of the monodispersed beads and the control of their porosity and textural properties is achieved by tailoring the silica and alginate loading, polycation concentration and incubation time during coacervation. This process has led to the formation of a remarkably robust hybrid material that confers exceptional protection to live cells against sheer stresses and contamination in a diverse range of applications. Dunaliella tertiolecta encapsulated within this hybrid core-shell system display high photosynthetic activity over a long duration (>1 year). This sustainable biotechnology could find use in high value chemical harvests and biofuel cells to photosynthetic solar cells (energy transformation, electricity production, water splitting technologies). Furthermore the material can be engineered into various forms from spheres to variable thickness films, broadening its potential applications.

  14. Highly efficient, long life, reusable and robust photosynthetic hybrid core-shell beads for the sustainable production of high value compounds.

    PubMed

    Desmet, Jonathan; Meunier, Christophe; Danloy, Emeric; Duprez, Marie-Eve; Lox, Frédéric; Thomas, Diane; Hantson, Anne-Lise; Crine, Michel; Toye, Dominique; Rooke, Joanna; Su, Bao-Lian

    2015-06-15

    An efficient one-step process to synthesize highly porous (Ca-alginate-SiO2-polycation) shell: (Na-alginate-SiO2) core hybrid beads for cell encapsulation, yielding a reusable long-life photosynthetically active material for a sustainable manufacture of high-value metabolites is presented. Bead formation is based on crosslinking of an alginate biopolymer and mineralisation of silicic acid in combination with a coacervation process between a polycation and the silica sol, forming a semi-permeable external membrane. The excellent mechanical strength and durability of the monodispersed beads and the control of their porosity and textural properties is achieved by tailoring the silica and alginate loading, polycation concentration and incubation time during coacervation. This process has led to the formation of a remarkably robust hybrid material that confers exceptional protection to live cells against sheer stresses and contamination in a diverse range of applications. Dunaliella tertiolecta encapsulated within this hybrid core-shell system display high photosynthetic activity over a long duration (>1 year). This sustainable biotechnology could find use in high value chemical harvests and biofuel cells to photosynthetic solar cells (energy transformation, electricity production, water splitting technologies). Furthermore the material can be engineered into various forms from spheres to variable thickness films, broadening its potential applications. PMID:25721859

  15. Alginate cryogel based glucose biosensor

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

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

    PubMed Central

    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

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

    PubMed

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

    2016-06-01

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

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

    PubMed

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

    2015-01-01

    Although alginate hydrogels have been extensively studied for tissue engineering applications, their utilization is limited by poor mechanical strength, rapid drug release, and a lack of cell adhesive ability. Aiming to improve these properties, we employ the interpenetrating hydrogel design rationale. Using alginate and sericin (a natural protein with many unique properties and a major component of silkworm silk), we develop an interpenetrating polymer network (IPN) hydrogel comprising 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. PMID:26205586

  19. One-step synthesis of platinum nanoparticles loaded in alginate bubbles.

    PubMed

    Yang, Chih-Hui; Wang, Wei-Ting; Grumezescu, Alexandru Mihai; Huang, Keng-Shiang; Lin, Yung-Sheng

    2014-01-01

    Composite particles with multifunctions have been extensively utilized for various applications. Bubble particles can be applied for ultrasound-mediated imaging, drug delivery, absorbers, cell culture, etc. This study proposes a one-step strategy to obtain Pt nanoparticles loaded in alginate bubbles. A needle-based droplet formation was used to generate uniform alginate particles about 2 mm in diameter. The hydrolysis reaction of NaBH4 was utilized to produce gaseous hydrogen and then trapped within alginate particles to form bubbles. The Pt(4+) mixed with alginate solution was dropped into the reservoir to react with reducing NaBH4 and hardening CaCl2 to form Pt nanoparticles-alginate composite bubbles. Results indicate that the size of bubbles decreases with the CaCl2 concentration (1% ~ 20%), and size of bubbles increases with the NaBH4 concentration (1 ~ 20 mM). The advantages for the present approach include low cost, easy operation, and effective production of Pt nanoparticles-alginate composite bubbles.

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

    PubMed

    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.

  1. Multi-featured macroporous agarose-alginate cryogel: synthesis and characterization for bioengineering applications.

    PubMed

    Tripathi, Anuj; Kumar, Ashok

    2011-01-10

    In this study agarose-alginate scaffolds are synthesized using cryogelation technology in different formats like monolith, sheet, discs, and beads, and show amiable mechanical strength like soft tissue properties and high interconnected macroporous degradable architecture. In cell-material interactions, fibroblast (NIH-3T3) cells showed good adherence and proliferation on these scaffolds presenting its potential application in soft tissue engineering. The application of cryogel beads and monoliths was also examined by the efficient immobilization of bacterial cells (BL21) on these matrices revealing their use for recovery of product from continuous fermentation systems without cell leakage. These scaffolds also showed potential as a filter for repeated recovery of heavy metal binding, such as copper and nickel from the waste water. The cryogels prepared herein do have a number of unique features that make them an important class of soft materials for developing multi-featured scaffolds as a novel carrier for bioengineering applications.

  2. Multi-featured macroporous agarose-alginate cryogel: synthesis and characterization for bioengineering applications.

    PubMed

    Tripathi, Anuj; Kumar, Ashok

    2011-01-10

    In this study agarose-alginate scaffolds are synthesized using cryogelation technology in different formats like monolith, sheet, discs, and beads, and show amiable mechanical strength like soft tissue properties and high interconnected macroporous degradable architecture. In cell-material interactions, fibroblast (NIH-3T3) cells showed good adherence and proliferation on these scaffolds presenting its potential application in soft tissue engineering. The application of cryogel beads and monoliths was also examined by the efficient immobilization of bacterial cells (BL21) on these matrices revealing their use for recovery of product from continuous fermentation systems without cell leakage. These scaffolds also showed potential as a filter for repeated recovery of heavy metal binding, such as copper and nickel from the waste water. The cryogels prepared herein do have a number of unique features that make them an important class of soft materials for developing multi-featured scaffolds as a novel carrier for bioengineering applications. PMID:21077225

  3. Stapled endosome disrupting alginate particles for cytosolic delivery of cations.

    PubMed

    Acharya, Abhinav P; Little, Steven R

    2015-01-01

    Divalent cations, the most prevalent minerals in the body, are responsible for a wide variety of cellular functions including signaling, proliferation, differentiation and cell death, and therefore their transmembrane transportation is tightly regulated. Despite the importance of divalent cations in cell activity, there are currently no intracellular delivery methods for divalent cations or modulation of intracellular levels of minerals. Here, we describe endosome disrupting alginate nanoparticles termed Alginoketals, which can deliver divalent cations to the cytosol of the cells. Alginoketals are generated by crosslinking alginic acid with endosome disrupting ketals, and using divalent cations as the stapling or binding agent. We show that Alginoketals were able to deliver copper (II) in the cytosol of the cancer cells thereby disrupting copper homeostasis and inducing cell death via accumulation of hydrogen peroxide. Alginoketal-copper (II)-based particles act as superoxide dismutase mimics and are the first class of divalent cation delivery vehicles, with potential application in cancer therapy, regenerative medicine and drug delivery.

  4. The effect of wax on compaction of microcrystalline cellulose beads made by extrusion and spheronization.

    PubMed

    Iloañusi, N O; Schwartz, J B

    1998-01-01

    The effect of wax on the deformation behavior and compression characteristics of microcrystalline cellulose (Avicel PH-101) and acetaminophen (APAP) beads is described. Beads of Avicel PH-101 and APAP formulations were prepared using extrusion and spheronization technology. A waxy material, glyceryl behenate, N.F. (Compritol), was added to the formulations in amounts ranging from 10% to 70% of total solid weight. Beads with a selected particle size range of 16-30 mesh were compressed with an instrumented single punch Manesty F press utilizing a 7/16-in. flat-faced tooling set. Compaction profiles were generated for the tablets to evaluate the effect of wax on the densification of beads containing wax. Beads made without wax (the control formulation) required greater compression forces to form cohesive tablets. As the amount of wax in the bead formulation was increased, the beads become more plastic and compressible. The Heckel equation which relates densification to compression pressure was used to evaluate the deformation mechanisms of the bead formulations. The analysis shows that as the level of wax in the bead formulation is increased, the yield pressure decreases, indicating that the beads densify by a plastic deformation mechanism.

  5. Mechanical properties of C-5 epimerized alginates.

    PubMed

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

    2008-09-01

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

  6. Immobilization of a thermostable alpha-amylase by covalent binding to an alginate matrix increases high temperature usability.

    PubMed

    Tee, Boon L; Kaletunç, Gönül

    2009-01-01

    Thermostable alpha-amylase was covalently bound to calcium alginate matrix to be used for starch hydrolysis at liquefaction temperature of 95 degrees C. 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride (EDAC) was used as crosslinker. EDAC reacts with the carboxylate groups on the calcium alginate matrix and the amine groups of the enzyme. Ethylenediamine tetraacetic acid (EDTA) treatment was applied to increase the number of available carboxylate groups on the calcium alginate matrix for EDAC binding. After the immobilization was completed, the beads were treated with 0.1 M calcium chloride solution to reinstate the bead mechanical strength. Enzyme loading efficiency, activity, and reusability of the immobilized alpha-amylase were investigated. Covalently bound thermostable alpha-amylase to calcium alginate produced a total of 53 g of starch degradation/mg of bound protein after seven consecutive starch hydrolysis cycles of 10 min each at 95 degrees C in a stirred batch reactor. The free and covalently bound alpha-amylase had maximum activity at pH 5.5 and 6.0, respectively. The Michaelis-Menten constant (K(m)) of the immobilized enzyme (0.98 mg/mL) was 2.5 times greater than that of the free enzyme (0.40 mg/mL). The maximum reaction rate (V(max)) of immobilized and free enzyme were determined to be 10.4-mg starch degraded/mL min mg bound protein and 25.7-mg starch degraded/mL min mg protein, respectively. The high cumulative activity and seven successive reuses obtained at liquefaction temperature make the covalently bound thermostable alpha-amylase to calcium alginate matrix, a promising candidate for use in industrial starch hydrolysis process. PMID:19353735

  7. Immobilization of a thermostable alpha-amylase by covalent binding to an alginate matrix increases high temperature usability.

    PubMed

    Tee, Boon L; Kaletunç, Gönül

    2009-01-01

    Thermostable alpha-amylase was covalently bound to calcium alginate matrix to be used for starch hydrolysis at liquefaction temperature of 95 degrees C. 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride (EDAC) was used as crosslinker. EDAC reacts with the carboxylate groups on the calcium alginate matrix and the amine groups of the enzyme. Ethylenediamine tetraacetic acid (EDTA) treatment was applied to increase the number of available carboxylate groups on the calcium alginate matrix for EDAC binding. After the immobilization was completed, the beads were treated with 0.1 M calcium chloride solution to reinstate the bead mechanical strength. Enzyme loading efficiency, activity, and reusability of the immobilized alpha-amylase were investigated. Covalently bound thermostable alpha-amylase to calcium alginate produced a total of 53 g of starch degradation/mg of bound protein after seven consecutive starch hydrolysis cycles of 10 min each at 95 degrees C in a stirred batch reactor. The free and covalently bound alpha-amylase had maximum activity at pH 5.5 and 6.0, respectively. The Michaelis-Menten constant (K(m)) of the immobilized enzyme (0.98 mg/mL) was 2.5 times greater than that of the free enzyme (0.40 mg/mL). The maximum reaction rate (V(max)) of immobilized and free enzyme were determined to be 10.4-mg starch degraded/mL min mg bound protein and 25.7-mg starch degraded/mL min mg protein, respectively. The high cumulative activity and seven successive reuses obtained at liquefaction temperature make the covalently bound thermostable alpha-amylase to calcium alginate matrix, a promising candidate for use in industrial starch hydrolysis process.

  8. Use of Ca-alginate as a novel support for TiO2 immobilization in methylene blue decolorisation.

    PubMed

    Albarelli, Juliana Q; Santos, Diego T; Murphy, Sharon; Oelgemöller, Michael

    2009-01-01

    This study provides a preliminary contribution to the development of an industrial process for the UV/TiO(2) water treatment by introducing a novel support for TiO(2) immobilization. For the following study, Methylene Blue (MB) was chosen as the model dye to evaluate this novel immobilization system. The results showed that TiO(2) immobilized in a Ca-alginate bead retained its photoactivity during all of the experiments and the TiO(2)-gel beads presented good stability in water for maintaining its shape after several uses. When a proportion of 10% (v/v) of these beads was used, the configuration system demonstrated an improved mass transfer and consequently enhanced degradation efficiency. Experiments were also performed using 'recycled' beads. The results showed an increase in the degradation efficiency when the beads were reused, with an eventual 'self-destructive' effect. These studies showed great promise regarding the recyclable reagents with a reduction in waste at no greater cost or reduction in efficiency. Therefore, the potential of TiO(2)-gel beads as a simple and environmentally friendly catalyst for continuous use was developed.

  9. Disposal of bead ion exchange resin wastes

    SciTech Connect

    Gay, R.L.; Granthan, L.F.

    1985-12-17

    Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means.

  10. Glass-bead peen plating

    NASA Technical Reports Server (NTRS)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  11. Alginate-modifying enzymes: biological roles and biotechnological uses

    PubMed Central

    Ertesvåg, Helga

    2015-01-01

    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 polymerization 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. An enzyme from Pseudomonas syringae with alginate deacetylase activity 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 pharmaceutical applications

  12. Dried calcium alginate/magnetite spheres: a new support for chromatographic separations and enzyme immobilization

    SciTech Connect

    Burns, M.A.; Kvesitadze, G.I.; Graves, D.J.

    1985-02-01

    Dried spheres made from an alginate solution containing magnetite particles have excellent potential as a support for enzyme immobilization and chromatographic applications. The beads were found to be much stronger than gels such as polyacrylamide and dextran, indicating that high flow rates and pressures could be used in column separations. The support withstood not only temperatures of up to 120/sup 0/C, but also most pH values and common solvents. While some solutions, such as phosphate buffers, dissolved the spheres, stabilization with Tyzor TE eliminated this problem. The physical properties of the beads include a glasslike density of 2.2 g/mL, excellent sphericity, low porosity, and a narrow size distribution. The magnetite present in the support allows the beads to be used for magnetic separations such as high gradient magnetic filtration. Their high degree of microroughness provides a large exposed surface area for enzyme and ligand binding. Mixed Actinomyces fradiae proteases and Aspergillus niger ..cap alpha..-amylase, two enzymes representative of classes which attack large substrates, were immobilized on the bead's surface with high activity and stability. A cyanuric dye which can be used in chromatographic applications (Cibacron Blue F3GA) was also readily coupled to the surface of this support with good yield.

  13. Polyaniline nanofibers assembled on alginate microsphere for Cu2+ and Pb2+ uptake.

    PubMed

    Jiang, Nina; Xu, Yiting; Dai, Yuqiong; Luo, Weiang; Dai, Lizong

    2012-05-15

    Polyaniline (PANI) nanofibers were assembled on the micro- or millimeter-scale calcium alginate (CA) beads by "competitive adsorption-restricted polymerization" approach. The CA beads made the dimensional expansion of PANI nanofibers evident, which overcame the serious aggregation of PANI nanofibers and benefited the practical operation of PANI nanofibers. Batch adsorption results showed that the millimeter-scale CA beads decorated by PANI nanofibers had high affinity to Cu(2+) and Pb(2+) in aqueous solutions. The removal percentages of Cu(2+) and Pb(2+) in aqueous solutions by this PANI/CA composite with milli/nano hierarchical structure surpassed 90% in a wide pH range from 3 to 7. Sorption of the two kinds of ions to PANI/CA composite sorbent agreed well with the Freundlich adsorption model. The adsorption kinetic results of Cu(2+) and Pb(2+) showed that the adsorption reached equilibrium within 120min and 40min, respectively. And their adsorption rates could be described by pseudo-second-order kinetics. The desorption percentages of Pb(2+) and Cu(2+) from this PANI/CA composite are 62% and 75%, respectively. The Pb(2+) and Cu(2+) removal capacity of the sorbent could be further reinforced when the diameter of CA beads turned from millimeter to micrometer.

  14. Folding of electrostatically charged beads-on-a-string as an experimental realization of a theoretical model in polymer science.

    PubMed

    Reches, Meital; Snyder, Phillip W; Whitesides, George M

    2009-10-20

    The "beads-on-a-string" model for folding of polymers is a cornerstone of theoretical polymer science. This communication describes a physical model of beads-on-a-string, based on the folding of flexible strings of electrostatically charged beads in two dimensions. The system comprises millimeter-scale Teflon and Nylon-6,6 (spherical or cylindrical) beads (approximately 6 mm in diameter) separated by smaller (approximately 3 mm) poly(methyl methacrylate) (PMMA) spherical beads, threaded on a flexible string. The smaller, uncharged beads define the distances between the larger beads, and control the flexibility of the string. During agitation of the sequence of beads on a planar, horizontal paper surface, tribocharging generates opposite electrostatic charges on the larger Nylon and Teflon beads, but leaves the smaller PMMA beads essentially uncharged; the resulting electrostatic interactions cause the string to fold. Examination and comparison of two models--one physical and one theoretical--may offer a new approach to understanding folding, collapse, and molecular recognition at an abstract level, with particular opportunity to explore the influence of the flexibility of the string and the shape of the beads on the pattern and rate of folding. The physical system is, thus, an analog computer, simulating the theoretical beads-on-a-string model in two dimensions; this system makes it possible to test hypotheses connecting "sequence" to "folding", rapidly and conveniently, while exploring nonlinearities and other complexities omitted from the theoretical model.

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

    PubMed

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

    2016-03-01

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

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

    PubMed

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

    2016-03-01

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

  17. Juxta-clavicular beaded lines.

    PubMed

    Franco, Gennaro; Donati, Pietro; Muscardin, Luca; Maini, Antonio; Morrone, Aldo

    2006-08-01

    We present a case series of 63 patients diagnosed with juxta-clavicular beaded lines. This condition is more frequent in dark-skinned people and corresponds to an anatomical variant of simple sebaceous hyperplasia. In view of the strong reactivity of the melanocytes in dark-skinned people, and of the possible hypochromic results, no treatment is advised.

  18. Juxta-clavicular beaded lines.

    PubMed

    Franco, Gennaro; Donati, Pietro; Muscardin, Luca; Maini, Antonio; Morrone, Aldo

    2006-08-01

    We present a case series of 63 patients diagnosed with juxta-clavicular beaded lines. This condition is more frequent in dark-skinned people and corresponds to an anatomical variant of simple sebaceous hyperplasia. In view of the strong reactivity of the melanocytes in dark-skinned people, and of the possible hypochromic results, no treatment is advised. PMID:16867005

  19. Calibration beads containing luminescent lanthanide ion complexes

    EPA Science Inventory

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  20. Biotransformation of L-tyrosine to Dopamine by a Calcium Alginate Immobilized Mutant Strain of Aspergillus oryzae.

    PubMed

    Ali, Sikander; Nawaz, Wajeeha

    2016-08-01

    The present research work is concerned with the biotransformation of L-tyrosine to dopamine (DA) by calcium alginate entrapped conidiospores of a mutant strain of Aspergillus oryzae. Different strains of A. oryzae were isolated from soil. Out of 13 isolated strains, isolate-2 (I-2) was found to be a better DA producer. The wild-type I-2 was chemically improved by treating it with different concentrations of ethyl methyl sulfonate (EMS). Among seven mutant variants, EMS-6 exhibiting maximal DA activity of 43 μg/ml was selected. The strain was further exposed with L-cysteine HCl to make it resistant against diversion and environmental stress. The conidiospores of selected mutant variant A. oryzae EMS-6 strain were entrapped in calcium alginate beads. Different parameters for immobilization were investigated. The activity was further improved from 44 to 62 μg/ml under optimized conditions (1.5 % sodium alginate, 2 ml inoculum, and 2 mm bead size). The best resistant mutant variable exhibited over threefold increase in DA activity (62 μg/ml) than did wild-type I-2 (21 μg/ml) in the reaction mixture. From the results presented in the study, it was observed that high titers of DA activity in vitro could effectively be achieved by the EMS-induced mutagenesis of filamentous fungus culture used.

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

    PubMed

    Ahmedi, Afaf; Abouseoud, Mahmoud; Abdeltif, Amrane; Annabelle, Couvert

    2015-01-01

    Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip "Brassica rapa" is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus Φ, and effective diffusion coefficients (D e ) of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate.

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

    PubMed Central

    Ahmedi, Afaf; Abouseoud, Mahmoud; Abdeltif, Amrane; Annabelle, Couvert

    2015-01-01

    Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip “Brassica rapa” is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus Φ, and effective diffusion coefficients (De) of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate. PMID:25734011

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

    PubMed

    Ahmedi, Afaf; Abouseoud, Mahmoud; Abdeltif, Amrane; Annabelle, Couvert

    2015-01-01

    Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip "Brassica rapa" is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus Φ, and effective diffusion coefficients (D e ) of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate. PMID:25734011

  4. Arsenite oxidation in batch reactors with alginate-immobilized ULPAs1 strain.

    PubMed

    Simeonova, Diliana D; Micheva, Kalina; Muller, Daniel A E; Lagarde, Florence; Lett, Marie-Claire; Groudeva, Veneta I; Lièvremont, Didier

    2005-08-20

    Arsenic is one of the major groundwater contaminants worldwide. It was previously demonstrated that the beta-proteobacterium Cenibacterium arsenoxidans has an efficient As[III] oxidation ability. The present study was conducted to evaluate the performance of alginate-immobilized ULPAs1 in the oxidation of As[III] to As[V] in batch reactors. A two-level full factorial experimental design was applied to investigate the influence of main parameters involved in the oxidation process, i.e., pH (7-8), temperature (4 degrees C-25 degrees C), kind of nutrient media (2%-20% sauerkraut brine), and arsenic concentration (10-100 mg/L). One hundred milligram per liter of As[III] was fully oxidized by calcium-alginate immobilized cells in 1 h. It was found that the temperature as well as the kind of nutrient media used were significant parameters at a 95% confidence interval whereas only temperature was a significant parameter at a 99% confidence interval. The immobilization of the As[III] oxidizing strain in alginate beads offers a promising way to implement new treatment processes in the remediation of arsenic contaminated waters.

  5. Removal of the organic content from a bleached kraft pulp mill effluent by a treatment with silica-alginate-fungi biocomposites.

    PubMed

    Duarte, Katia; Justino, Celine I L; Pereira, Ruth; Panteleitchouk, Teresa S L; Freitas, Ana C; Rocha-Santos, Teresa A P; Duarte, Armando C

    2013-01-01

    This study attempts a treatment strategy of a bleached kraft pulp mill effluent with Rhizopus oryzae or Pleurotus sajor caju encapsulated on silica-alginate (biocomposite of silica-alginate-fungi, with the purpose of reducing its potential impact in the environment. Active (alive) or inactive (death by sterilization) Rhizopus oryzae or Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the bleached kraft pulp mill effluent. The treatment of bleached kraft pulp mill effluent by active and inactive biocomposites was performed throughout 29 days at 28°C. The efficiency of treatment was evaluated by measuring the removal of organic compounds, chemical oxygen demand and the relative absorbance ratio over time. Both fungi species showed potential for removal of organic compounds, colour and chemical oxygen demand. Maximum values of reduction in terms of colour (56%), chemical oxygen demand (65%) and organic compounds (72-79%) were attained after 29 days of treatment of bleached kraft pulp mill effluent by active Rhizopus oryzae biocomposites. The immobilization of fungi, the need for low fungal biomass, and the possibility of reutlization of the biocomposites clearly demonstrate the industrial and environmental interest in bleached kraft pulp mill effluent treatment by silica-alginate-fungi biocomposites. PMID:23043338

  6. How to build an adapted and bioactive cell microenvironment? A chemical interaction study of the structure of Ca-alginate matrices and their repercussion on confined cells.

    PubMed

    Bienaimé, Christophe; Barbotin, Jean-Noël; Nava-Saucedo, José-Edmundo

    2003-11-01

    Alginates are increasingly being used as medical materials (matrices for tissue regeneration, surgical sponges, hemostatic bandages, microbial and cell encapsulation, artificial bacterial biofilms, etc.). The constitution of alginate gel networks is a complex phenomenon. A great number of different kinds of polysaccharidic frameworks can come to existence depending on the conditions used for their attainment. For instance, the degree of heterogeneity and porosity of Ca-alginate beads rely on this molecular organization. The formation of structural irregularities (superficial crust, cavities, shafts, dense or light gel frameworks, ordered or chaotic domains, etc.) within the alginate gel beads are inherent to this skeletal design. Several specific staining molecules (e.g. calcon carboxylic acid, murexide, methylene blue) that are negatively or positively charged interact with the gel network. These molecules allowed us to reveal a great variety of chemical interactions shown by the pattern coloration of the internal structure of the gel. The results observed are very different for the several matrices analyzed, which could explain to a great extent the singular behavior that cells confined in these kind of matrices exhibit.

  7. Evaluation of various parameters of calcium-alginate immobilization method for enhanced alkaline protease production by Bacillus licheniformis NCIM-2042 using statistical methods.

    PubMed

    Potumarthi, Ravichandra; Subhakar, Ch; Pavani, A; Jetty, Annapurna

    2008-04-01

    Calcium-alginate immobilization method for the production of alkaline protease by Bacillus licheniformis NCIM-2042 was optimized statistically. Four variables, such as sodium-alginate concentration, calcium chloride concentration, inoculum size and agitation speed were optimized by 2(4) full factorial central composite design and subsequent analysis and model validation by a second-order regression equation. Eleven carbon, 11 organic nitrogen and seven inorganic nitrogen sources were screened by two-level Plackett-Burman design for maximum alkaline protease production by using optimized immobilized conditions. The levels of four variables, such as Na-alginate 2.78%; CaCl(2), 2.15%; inoculum size, 8.10% and agitation, 139 rpm were found to be optimum for maximal production of protease. Glucose, soybean meal and ammonium sulfate were resulted in maximum protease production at 644 U/ml, 720 U/ml, and 806 U/ml when screened for carbon, organic nitrogen and inorganic nitrogen sources, respectively, using optimized immobilization conditions. Repeated fed batch mode of operation, using optimized immobilized conditions, resulted in continuous operation for 12 cycles without disintegration of beads. Cross-sectional scanning electron microscope images have shown the growth pattern of B. licheniformis in Ca-alginate immobilized beads.

  8. Ethanol production from sugar beet molasses by S. cerevisiae entrapped in an alginate-maize stem ground tissue matrix.

    PubMed

    Razmovski, R; Vučurović, V

    2011-04-01

    A new alginate-maize stem ground tissue matrix was developed as a Saccharomyces cerevisiae carrier for ethanol fermentation from sugar beet molasses. There were several fermentation procedures in the present study: using free cells and alginate-entrapped cells with and without maize stem ground tissue supplementation (F; F+C; AB; AB+C), and using a new combined alginate-maize stem ground tissue carrier (ABC). It was found that addition of maize stem ground tissue meal (C), with honeycomb configuration, provided high surface areas for cell attachment and biofilm growth, and also increased alginate matrix porosity, enabling better mass transfer characteristic, better physical strength and stability of beads. The highest values of process parameters were obtained in the case of new carrier (ABC): the ethanol concentration of 60.36 g/l, percentage of the theoretical ethanol yield of 96.56%, ethanol yield of 0.493 g/g and the volumetric ethanol productivity of 2.51 g/lh. The medium supplementation with maize stem ground tissue significantly decreased acetaldehyde and acetic acid content, did not affect fusel alcohol and ethylacetate content of the distillate.

  9. Encapsulation of R. planticola Rs-2 from alginate-starch-bentonite and its controlled release and swelling behavior under simulated soil conditions.

    PubMed

    Wu, Zhansheng; Guo, Lina; Qin, Shaohua; Li, Chun

    2012-02-01

    The plant growth-promoting bacteria (PGPR) Raoultella planticola Rs-2 was encapsulated with the various blends of alginate, starch, and bentonite for development of controlled-release formulations. The stability and release characteristics of these different capsule formulations were evaluated. The entrapment efficiency of Rs-2 in the beads (capsules) was more than 99%. The diameter of dry beads ranged from 0.98 to 1.41 mm. The bacteria release efficiency, swelling ratio, and biodegradability of the different bead formulations were enhanced by increasing the starch or alginate contents, but were impeded by higher bentonite content. The release kinetics of viable cells from capsules and the swelling ratio of capsules were studied in simulated soil media of varying temperature, moisture, pH, and salt content. The release of loaded Rs-2 cells and swelling of capsules are greatly affected by moisture, temperature, pH and salt content of the release medium. The release of viable Rs-2 cells from capsules was positively associated with the swelling properties of the capsules. The release of Rs-2 cells occurred through a Case II diffusion mechanism. In summary, this work indicates that alginate-starch-bentonite blends are a viable option for the development of efficient controlled-release formulations of Rs-2 biofertilizer, and which could have a promising application in natural field conditions. PMID:21879356

  10. Encapsulation of R. planticola Rs-2 from alginate-starch-bentonite and its controlled release and swelling behavior under simulated soil conditions.

    PubMed

    Wu, Zhansheng; Guo, Lina; Qin, Shaohua; Li, Chun

    2012-02-01

    The plant growth-promoting bacteria (PGPR) Raoultella planticola Rs-2 was encapsulated with the various blends of alginate, starch, and bentonite for development of controlled-release formulations. The stability and release characteristics of these different capsule formulations were evaluated. The entrapment efficiency of Rs-2 in the beads (capsules) was more than 99%. The diameter of dry beads ranged from 0.98 to 1.41 mm. The bacteria release efficiency, swelling ratio, and biodegradability of the different bead formulations were enhanced by increasing the starch or alginate contents, but were impeded by higher bentonite content. The release kinetics of viable cells from capsules and the swelling ratio of capsules were studied in simulated soil media of varying temperature, moisture, pH, and salt content. The release of loaded Rs-2 cells and swelling of capsules are greatly affected by moisture, temperature, pH and salt content of the release medium. The release of viable Rs-2 cells from capsules was positively associated with the swelling properties of the capsules. The release of Rs-2 cells occurred through a Case II diffusion mechanism. In summary, this work indicates that alginate-starch-bentonite blends are a viable option for the development of efficient controlled-release formulations of Rs-2 biofertilizer, and which could have a promising application in natural field conditions.

  11. Alginate dressing as a donor site haemostat.

    PubMed Central

    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. Images Fig. 1 PMID:3511833

  12. Improvement of bioethanol productivity of immobilized Saccharomyces bayanus with using sodium alginate-graft-poly(N-vinyl-2-pyrrolidone) matrix.

    PubMed

    İnal, Murat; Yiğitoğlu, Mustafa

    2012-09-01

    In this study, immobilization conditions and bioethanol production characteristics of immobilized Saccharomyces bayanus were investigated into sodium alginate-graft-poly(N-vinyl-2-pyrrolidone; NaAlg-g-PVP) matrix. The matrix that crosslinked with calcium clorid was used for immobilization of S. bayanus. Bioethanol productivity of the NaAlg-g-PVP matrix was found to increase from 4.21 to 4.84 gL(-1) h(-1) when compared with the convential sodium alginate matrix. The production of bioethanol was affected by initial glucose concentration and percentage of immobilized cell beads in fermentation medium. Bioethanol productivity was increased from 3.62 to 4.84 gL(-1) h(-1) while the glucose concentration increasing from 50 to 100 gL(-1). Due to the increase in percentage from 10 to 20 % of immobilized cell beads in the fermentation medium, bioethanol productivity was increased from 4.84 to 8.68 gL(-1) h(-1). The cell immobilized NaAlg-g-PVP beads were protected 92 % of initial activity after six repeated fermentation.

  13. Lead removal in rats using calcium alginate.

    PubMed

    Savchenko, Olga V; Sgrebneva, Marina N; Kiselev, Vladimir I; Khotimchenko, Yuri S

    2015-01-01

    Lead (Pb) exposure, even at low levels, causes a variety of health problems. The aims of this study were to investigate the tissue distribution of lead in the bodies of rats, to evaluate lead removal from the internal organs and bones using calcium alginate in doses of 500, 200 and 100 mg/kg per day for 28 days and to assess the impact of calcium alginate on the level of essential elements. Lead (Pb), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) levels in the blood, hearts, kidneys, livers and femurs of the experimental animals were measured using mass spectrometry with inductively coupled plasma. The results revealed that lead acetate exposure increased the levels of Pb in the blood and organs of the animals and significantly reduced contents of Ca, Mn, Fe, Cu and Zn. Treatment with calcium alginate in dose 500 mg/kg contributed to significant decreases in the amount of lead in the kidney, heart and bones of animals and a slight increase in the content of essential elements in the liver, kidneys and heart, although these changes were not significant. Decreasing of lead was not significant in the internal organs, bones and blood of animals treated with calcium alginate 200 and 100 mg/kg. Consequently, calcium alginate dose of 500 mg/kg more efficiently removes lead accumulated in the body. Calcium alginate does not have negative effect on level of essential elements quite the contrary; reducing the levels of lead, calcium alginate helps normalize imbalances of Ca, Mn, Fe, Cu and Zn. The results of this study suggest that calcium alginate may potentially be useful for the treatment and prevention of heavy metal intoxications. PMID:25062547

  14. Cellobiose hydrolysis using Pichia etchellsii cells immobilized in calcium alginate

    SciTech Connect

    Jain, D.; Ghose, T.K.

    1984-04-01

    Cellulose degradation rates can be increased by the hydrolysis of cellobiose using immobilized beta-glucosidase. Production of beta-glucosidase in four yeasts was studied and a maximum activity of 1.22 IU/mg cells was obtained in cells of Pichia etchellsii grown on 3% cellobiose. The immobilization of beta-glucosidase containing cells on various solid supports was studied and entrapment in calcium alginate gel beads was found to be the best method. After ten sequential batch uses of the preparation, 96.5% of the initial activity was retained. The pH and temperature optima for free and immobilized cells were pH 6.5 (0.05M Maleate buffer) and 50/sup 0/C however, the enzyme has a better thermal stability at 45/sup 0/C. Beads stored at 4/sup 0/C for six months retain 80% of their activity. Kinetic studies performed on free and immobilized cells show that glucose is a noncompetitive product inhibitor. The immobilized preparation was limited by pore diffusion but exhibited no film-diffusion resistance during packed bed reactor operation. Good plug flow characteristics were observed. A model for reaction with pore diffusion for a noncompetitive type of inhibited system was developed and applied to this system. The reation rate with diffusional limitations was determined by using the model and effectiveness factors were calculated for different particle sizes. The modified rate expression using the effectiveness factor represented batch and packed bed reactor operation satisfactorily. The productivity in the packed bed column fell rapidly with an increase in conversion rate indicating that the operating conditions of the column would have to balance high conversion rates with acceptable productivity. The half-life in the column was affected by temperature, increasing to over seventeen days at 40/sup 0/C and decreasing to less than two days at 50/sup 0/C.

  15. Two-bead microrheology: Modeling protocols

    NASA Astrophysics Data System (ADS)

    Hohenegger, Christel; Forest, M. Gregory

    2008-09-01

    Microbead rheology maps the fluctuations of beads immersed in soft matter to viscoelastic properties of the surrounding medium. In this paper, we present modeling extensions of the seminal results of Mason and Weitz [Phys. Rev. Lett. 74, 1250 (1995)] for a single bead and of Crocker [Phys. Rev. Lett. 85, 888 (2000)] and Levine and Lubensky [Phys. Rev. Lett. 85, 1774 (2000)] for two beads. We formulate the linear response analysis for two beads so that the model equations retain the local diffusive properties of each bead (through the memory kernel of the shell or depletion zone surrounding each bead) and the nonlocal dynamic moduli of the medium separating the beads (through the memory kernel that transmits fluctuations of one bead to the other). We then derive a 3×3 invertible system of equations relating: an isolated bead’s autocorrelations, the autocorrelations and cross-correlations of two coupled beads; and the shell radius surrounding each bead, the memory kernels of the shell, and of the medium between the two beads.

  16. Freeze-thaw induced gelation of alginates.

    PubMed

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

    2016-09-01

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

  17. Prednisolone Delivery Platforms: Capsules and Beads Combination for a Right Timing Therapy.

    PubMed

    Cerciello, Andrea; Auriemma, Giulia; Morello, Silvana; Aquino, Rita P; Del Gaudio, Pasquale; Russo, Paola

    2016-01-01

    In this work, a platform of alginate beads loaded with Prednisolone in hypromellose/gellan gum capsules (F6/Cps) able to delay steroidal anti-inflammatory drug (SAID) release as needed for chronotherapy of rheumatoid arthritis is proposed. Rheumatoid arthritis, showing a worsening in symptoms in the morning upon waking, is a pathology that can benefit from chronotherapy. With the aim to maximize prednisolone therapeutic action allowing the right timing of glucocorticoid therapy, different engineered microparticles (gel-beads) were manufactured using prilling (laminar jet break-up) as micro-encapsulation technique and Zn-alginate as gastroresistant carrier. Starting from various feed solutions and process parameters, the effect of the variables on particles size, morphology, solid state properties and drug release was studied. The optimization of operative and prilling/ionotropic gelation variables led to microspheres with almost spherical shape and a narrow dimensional range. The feed solution with the highest alginate (2.5% w/v) amount and drug/polymer ratio (1:5 w/w) gave rise to the highest encapsulation efficiency (78.5%) as in F6 formulation. As to drug release, F6 exhibited an interesting dissolution profile, releasing about 24% of the drug in simulated gastric fluid followed by a more sustained profile in simulated intestinal fluid. #F6, acting as a gastro-resistant and delayed release formulation, was selected for in vivo studies on male Wistar rats by means of a carrageenan-induced oedema model. Finally, this efficacious formulation was used as core material for the development of a final dosage form: F6/Cps allowed to significantly reduce prednisolone release in simulated gastric fluid (12.6%) and delayed drug release up to about 390 minutes. PMID:27472446

  18. Prednisolone Delivery Platforms: Capsules and Beads Combination for a Right Timing Therapy.

    PubMed

    Cerciello, Andrea; Auriemma, Giulia; Morello, Silvana; Aquino, Rita P; Del Gaudio, Pasquale; Russo, Paola

    2016-01-01

    In this work, a platform of alginate beads loaded with Prednisolone in hypromellose/gellan gum capsules (F6/Cps) able to delay steroidal anti-inflammatory drug (SAID) release as needed for chronotherapy of rheumatoid arthritis is proposed. Rheumatoid arthritis, showing a worsening in symptoms in the morning upon waking, is a pathology that can benefit from chronotherapy. With the aim to maximize prednisolone therapeutic action allowing the right timing of glucocorticoid therapy, different engineered microparticles (gel-beads) were manufactured using prilling (laminar jet break-up) as micro-encapsulation technique and Zn-alginate as gastroresistant carrier. Starting from various feed solutions and process parameters, the effect of the variables on particles size, morphology, solid state properties and drug release was studied. The optimization of operative and prilling/ionotropic gelation variables led to microspheres with almost spherical shape and a narrow dimensional range. The feed solution with the highest alginate (2.5% w/v) amount and drug/polymer ratio (1:5 w/w) gave rise to the highest encapsulation efficiency (78.5%) as in F6 formulation. As to drug release, F6 exhibited an interesting dissolution profile, releasing about 24% of the drug in simulated gastric fluid followed by a more sustained profile in simulated intestinal fluid. #F6, acting as a gastro-resistant and delayed release formulation, was selected for in vivo studies on male Wistar rats by means of a carrageenan-induced oedema model. Finally, this efficacious formulation was used as core material for the development of a final dosage form: F6/Cps allowed to significantly reduce prednisolone release in simulated gastric fluid (12.6%) and delayed drug release up to about 390 minutes.

  19. Prednisolone Delivery Platforms: Capsules and Beads Combination for a Right Timing Therapy

    PubMed Central

    Cerciello, Andrea; Auriemma, Giulia; Morello, Silvana; Aquino, Rita P.; Del Gaudio, Pasquale

    2016-01-01

    In this work, a platform of alginate beads loaded with Prednisolone in hypromellose/gellan gum capsules (F6/Cps) able to delay steroidal anti-inflammatory drug (SAID) release as needed for chronotherapy of rheumatoid arthritis is proposed. Rheumatoid arthritis, showing a worsening in symptoms in the morning upon waking, is a pathology that can benefit from chronotherapy. With the aim to maximize prednisolone therapeutic action allowing the right timing of glucocorticoid therapy, different engineered microparticles (gel-beads) were manufactured using prilling (laminar jet break-up) as micro-encapsulation technique and Zn-alginate as gastroresistant carrier. Starting from various feed solutions and process parameters, the effect of the variables on particles size, morphology, solid state properties and drug release was studied. The optimization of operative and prilling/ionotropic gelation variables led to microspheres with almost spherical shape and a narrow dimensional range. The feed solution with the highest alginate (2.5% w/v) amount and drug/polymer ratio (1:5 w/w) gave rise to the highest encapsulation efficiency (78.5%) as in F6 formulation. As to drug release, F6 exhibited an interesting dissolution profile, releasing about 24% of the drug in simulated gastric fluid followed by a more sustained profile in simulated intestinal fluid. #F6, acting as a gastro-resistant and delayed release formulation, was selected for in vivo studies on male Wistar rats by means of a carrageenan-induced oedema model. Finally, this efficacious formulation was used as core material for the development of a final dosage form: F6/Cps allowed to significantly reduce prednisolone release in simulated gastric fluid (12.6%) and delayed drug release up to about 390 minutes. PMID:27472446

  20. Alginate immobilization of Escherichia coli MTCC 1652 whole cells for bioconversion of glycyrrhizinic acid and into 18-beta glycyrrhetinic acid.

    PubMed

    Ahmad, M; Panda, B P

    2013-12-15

    Microbial biotransformation of Glycyrrhizinic acid (GL) into 18-beta Glycyrrhetinic Acid (GA) was achieved using Escherichia coli MTCC 1652 whole cell. The E. coli whole cell was immobilized by entrapment method within calcium alginate beads using cell suspension of equal volume with sodium alginate 8%. The pH of solution, reaction volume and % of GL were optimized during the immobilization procedure and optimum pH 6.5, reaction volume of 4 mL and at 3% GL concentration for 12 h of incubation time showed highest concentration of GA (72.649 microg mL(-1)) with 76% bioconversion of GL to GA. Under optimized condition the immobilized cell produces 58.663 microg per mL of GA in licorice root extract containing 95.118 microg of GL per mL of the extract with 61% conversion at 12 h.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Sciatic nerve regeneration through alginate with tubulation or nontubulation repair in cat.

    PubMed

    Sufan, W; Suzuki, Y; Tanihara, M; Ohnishi, K; Suzuki, K; Endo, K; Nishimura, Y

    2001-03-01

    A novel material for nerve regeneration, alginate, was employed in both tubulation and nontubulation repair of a long peripheral nerve defect injury. Twelve cats underwent severing of the right sciatic nerve to generate a 50-mm gap, which was treated by tubulation repair (n = 6) or nontubulation repair (n = 6). In the tubulation group, a nerve conduit consisting of polyglycolic acid mesh tube filled with alginate sponge was implanted into the gap and the tube was sutured to both nerve stumps. In the nontubulation group, the nerve defect was repaired by a simple interpolation of two pieces of alginate sponge without any suture. The animals in both groups exhibited similar recovery of locomotor function. Three months postoperatively, successful axonal elongation and reinnervation in both the afferent and efferent systems were detected by electrophysiological examinations. Intracellular electrical activity was also recorded, which is directly indicative of continuity of the regenerated nerve and restoration of the spinal reflex circuit. Eight months after operation, many regenerated myelinated axons with fascicular organization by perineurial cells were observed within the gap, peroneal and tibial branches were found in both groups, while no alginate residue was found within the regenerated nerves. In morphometric analysis of the axon density and diameter, there were no significant differences between the two groups. These results suggest that alginate is a potent material for promoting peripheral nerve regeneration. It can also be concluded that the nontubulation method is a possible repair approach for peripheral nerve defect injury.

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

    PubMed Central

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

    2015-01-01

    Although alginate hydrogels have been extensively studied for tissue engineering applications, their utilization is limited by poor mechanical strength, rapid drug release, and a lack of cell adhesive ability. Aiming to improve these properties, we employ the interpenetrating hydrogel design rationale. Using alginate and sericin (a natural protein with many unique properties and a major component of silkworm silk), we develop an interpenetrating polymer network (IPN) hydrogel comprising 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. PMID:26205586

  4. Viper and Cobra Venom Neutralization by Alginate Coated Multicomponent Polyvalent Antivenom Administered by the Oral Route

    PubMed Central

    Bhattacharya, Sourav; Chakraborty, Mousumi; Mukhopadhyay, Piyasi; Kundu, P. P.; Mishra, Roshnara

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-01-01

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

  6. Formulation of an alginate-vineyard pruning waste composite as a new eco-friendly adsorbent to remove micronutrients from agroindustrial effluents.

    PubMed

    Vecino, X; Devesa-Rey, R; Moldes, A B; Cruz, J M

    2014-09-01

    The cellulosic fraction of vineyard pruning waste (free of hemicellulosic sugars) was entrapped in calcium alginate beads and evaluated as an eco-friendly adsorbent for the removal of different nutrients and micronutrients (Mg, P, Zn, K, N-NH4, SO4, TN, TC and PO4) from an agroindustrial effluent (winery wastewater). Batch adsorption studies were performed by varying the amounts of cellulosic adsorbent (0.5-2%), sodium alginate (1-5%) and calcium chloride (0.05-0.9M) included in the biocomposite. The optimal formulation of the adsorbent composite varied depending on the target contaminant. Thus, for the adsorption of cationic contaminants (Mg, Zn, K, N-NH4 and TN), the best mixture comprised 5% sodium alginate, 0.05M calcium chloride and 0.5% cellulosic vineyard pruning waste, whereas for removal of anionic compounds (P, SO4 and PO4), the optimal mixture comprised 1% sodium alginate, 0.9M calcium chloride and 0.5% cellulosic vineyard pruning waste. To remove TC from the winery wastewater, the optimal mixture comprised 3% of sodium alginate, 0.475M calcium chloride and 0.5% cellulosic vineyard pruning waste.

  7. Characterizing protein modifications by reactive metabolites using magnetic bead bioreactors and LC-MS/MS.

    PubMed

    Li, Dandan; Fu, You-Jun; Rusling, James F

    2015-03-18

    We report here label-free metabolite-protein adduct detection and identification employing magnetic beads coated with metabolic enzymes as bioreactors to generate metabolites and possible metabolite-protein adducts for analysis by liquid chromatography-tandem mass spectrometry.

  8. Using double-poured alginate impressions to fabricate bleaching trays.

    PubMed

    Haywood, V B; Powe, A

    1998-01-01

    Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal.

  9. Ionene modified small polymeric beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1977-01-01

    Linear ionene polyquaternary cationic polymeric segments are bonded by means of the Menshutkin reaction (quaternization) to biocompatible, extremely small, porous particles containing halide or tertiary amine sites which are centers for attachment of the segments. The modified beads in the form of emulsions or suspensions offer a large, positively-charged surface area capable of irreversibly binding polyanions such as heparin, DNA, RNA or bile acids to remove them from solution or of reversibly binding monoanions such as penicillin, pesticides, sex attractants and the like for slow release from the suspension.

  10. Multiplex Immunoassays: Chips and Beads

    PubMed Central

    2010-01-01

    Multiplex analysis is intended to simultaneously look for multiple targets in one sample. This approach has been largely adopted in genomics and progressively expands to various domains of laboratory investigation. In protein analysis, immunoassays are the fundamental methods and their multiplexing and miniaturization is of great applicability to both basic and applied research. Furthermore, the potential of these high-throughput methodologies can be foreseen in the field of clinical diagnostics. The following text describes planar and bead-based arrays, two main strategies of immunoassay multiplexing. Principles, detection methods and strengths of each are shortly discussed. Finally, we mention several challenges linked with the integration of these methods to diagnostics.

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

    PubMed Central

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

    2016-01-01

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

  12. Changes in the metabolism of the microalga Chlorella vulgaris when coimmobilized in alginate with the nitrogen-fixing Phyllobacterium myrsinacearum.

    PubMed

    Gonzalez-Bashan, L E; Lebsky, V K; Hernandez, J P; Bustillos, J J; Bashan, Y

    2000-07-01

    In an agroindustrial wastewater pond, a naturally occurring unicellular microalga, Chlorella vulgaris, was closely associated with the terrestrial plant-associative N2-fixing bacterium Phyllobacterium myrsinacearum. When the two microorganisms were artificially coimmobilized in alginate beads, they shared the same internal bead cavities, and the production of five microalgal pigments increased, but there were no effects on the number of the cells or the biomass of the microalga. The association, however, reduces the ability of C. vulgaris to remove ammonium ions and phosphorus from water. The bacterium produced nitrate from ammonium in synthetic wastewater with or without the presence of the microalga, and fixed nitrogen in two culture media. Our results suggest that interactions between microalgae and associative bacteria should be considered when cultivating microalgae for wastewater treatment.

  13. Reagentless cell lysis on a PDMS CD using beads

    NASA Astrophysics Data System (ADS)

    Kim, Jitae; Jang, She-Hee; Zoval, Jim V.; Da Silva, Nancy A.; Madou, Marc J.

    2004-08-01

    Reagentless mechanical cell lysis was demonstrated on a microfluidic CD (Compact Disc) microfabricated in PDMS (Polydimethylsiloxane). The motion of beads in a lysis chamber on the CD causes disruption of mammalian (CHO-K1), bacterial (Escherichia coli), and yeast (Saccharomyces cerevisiae) cells. Interactions between beads and cells are generated in the rimming flow established inside a partially filled annular chamber in the CD rotating around a horizontal axis. To maximize bead-cell interactions, the CD was spun forward and backwards around this axis, using high acceleration for up to 7 minutes. Based on our theoretical work, we investigated the following control parameters: bead density, angular velocity, acceleration rate, and solid volume fraction, all of which influence cell lysis efficiency. Cell disruption efficiency was verified either through direct microscopic viewing or measurement of DNA concentration after cell lysing. Lysis efficiency relative to a conventional lysis protocol was also determined. In the long term, this work is geared towards CD based sample-to-answer nucleic acid analysis which will include cell lysis, DNA purification, DNA amplification, and DNA hybridization detection.

  14. Physicochemical design of the morphology and ultrastructure of cellulose beads.

    PubMed

    Trygg, Jani; Fardim, Pedro; Gericke, Martin; Mäkilä, Ermei; Salonen, Jarno

    2013-03-01

    Cellulose was dissolved in NaOH-urea-water and beads were prepared by coagulation into nitric acid as well as saline solution. Morphology and ultrastructure of the beads were modified by controlling the molarity of the acid (0-10M) and temperature (5-50°C) of the coagulation media and the cellulose concentration (3-7%). The beads were characterized by optical image analysis (shape, volume, and size distribution) and weight (total porosity). Cross-sections of CO2 critical point dried beads were studied by field emission scanning electron microscopy (FE-SEM) and specific surface areas of 336-470m(2)g(-1) were determined from nitrogen adsorption isoterms. Pore size distribution was analyzed using solute exclusion technique. Our results demonstrate that the ultrastructure can be controlled by alteration of the coagulation conditions. Changes in size, shape and surface area were substential. Also generation of micro- (⩽2Å), meso-, or macropores (⩾50Å) can be favored.

  15. Selection of bead-displayed, PNA-encoded chemicals

    PubMed Central

    Gassman, Natalie R.; Nelli, J. Patrick; Dutta, Samrat; Kuhn, Adam; Bonin, Keith; Pianowski, Zbigniew; Winssinger, Nicolas; Guthold, Martin; Macosko, Jed C.

    2010-01-01

    The lack of efficient identification and isolation methods for specific molecular binders has fundamentally limited drug discovery. Here, we have developed a method to select peptide nucleic acid (PNA) encoded molecules with specific functional properties from combinatorially generated libraries. This method consists of three essential stages: (1) creation of a Lab-on-Bead™ library, a one-bead, one-sequence library that, in turn, displays a library of candidate molecules, (2) fluorescence microscopy-aided identification of single target-bound beads and the extraction – wet or dry – of these beads and their attached candidate molecules by a micropipette manipulator, and (3) identification of the target-binding candidate molecules via amplification and sequencing. This novel integration of techniques harnesses the sensitivity of DNA detection methods and the multiplexed and miniaturized nature of molecule screening to efficiently select and identify target-binding molecules from large nucleic acid encoded chemical libraries. Beyond its potential to accelerate assays currently used for the discovery of new drug candidates, its simple bead-based design allows for easy screening over a variety of prepared surfaces that can extend this technique's application to the discovery of diagnostic reagents and disease markers. PMID:19957300

  16. Beads, beaded-fibres and fibres: Tailoring the morphology of poly(caprolactone) using pressurised gyration.

    PubMed

    Hong, Xianze; Edirisinghe, Mohan; Mahalingam, Suntharavathanan

    2016-12-01

    This work focuses on forming bead on string poly(caprolactone) (PCL) by using gyration under pressure. The fibre morphology of bead on string is an interesting feature that falls between bead-free fibres and droplets, and it could be effectively controlled by the rheological properties of spinning dopes and the major processing parameters of the pressurised gyration system which are working pressure and rotating speed. Bead products were not always spherical in shape and tended to be more elliptical, therefore both their width and length were measured. The average bead width and length produced spanned a range 145-660μm and 140-1060μm, respectively. The average distance between two adjacent beads (i.e. inter-bead distance) and the bead size (width and length) are shown to be a function of processing parameters and polymer concentration. An interesting morphology i.e. beads with short fibre was observed when using a high polymer concentration. Bead on string structure agglomeration was promoted by a low polymer concentration. Formation of droplets or agglomerated bead on string is promoted below 5wt% polymer concentration, and beads with short fibre were present in the microstructure beyond a polymer concentration of 20wt%. PMID:27612839

  17. Fed batch bioconversion of 2-propanol by a solvent tolerant strain of Alcaligenes faecalis entrapped in Ca-alginate gel.

    PubMed

    Mohammad, Balsam T; Bustard, Mark T

    2008-07-01

    A gram-negative, rod-shaped, aerobe, capable of converting 2-propanol (isopropanol, IPA) to acetone was isolated from an oil/sump, and identified by 16 S rDNA analysis as Alcaligenes faecalis. Investigations showed this strain to be extremely solvent-tolerant and it was subsequently named ST1. In this study, A. faecalis ST1 cells were immobilized by entrapment in Ca-alginate beads (3 mm in diameter), and used in the bioconversion of high concentration IPA. The biodegradation rates and the corresponding microbial growth inside the beads were measured at four different IPA concentration ranges from 2 to 15 g l(-1). The maximum cell concentration obtained was 9.59 g dry cell weight (DCW) l(-1) medium which equated to 66 g DCW l(-1) gel, at an initial IPA concentration of 15 g l(-1) after 216 h of incubation. A maximum biodegradation rate of 0.067 g IPA g cells(-1) h(-1) was achieved for 5 g l(-1) IPA where an increase in IPA concentration to 38 g l(-1) caused reduction in bead integrity. A modified growth medium was developed which allowed repeated use of the beads for more than 42 days without any loss of integrity and continued bioconversion activity. PMID:18293022

  18. Fed batch bioconversion of 2-propanol by a solvent tolerant strain of Alcaligenes faecalis entrapped in Ca-alginate gel.

    PubMed

    Mohammad, Balsam T; Bustard, Mark T

    2008-07-01

    A gram-negative, rod-shaped, aerobe, capable of converting 2-propanol (isopropanol, IPA) to acetone was isolated from an oil/sump, and identified by 16 S rDNA analysis as Alcaligenes faecalis. Investigations showed this strain to be extremely solvent-tolerant and it was subsequently named ST1. In this study, A. faecalis ST1 cells were immobilized by entrapment in Ca-alginate beads (3 mm in diameter), and used in the bioconversion of high concentration IPA. The biodegradation rates and the corresponding microbial growth inside the beads were measured at four different IPA concentration ranges from 2 to 15 g l(-1). The maximum cell concentration obtained was 9.59 g dry cell weight (DCW) l(-1) medium which equated to 66 g DCW l(-1) gel, at an initial IPA concentration of 15 g l(-1) after 216 h of incubation. A maximum biodegradation rate of 0.067 g IPA g cells(-1) h(-1) was achieved for 5 g l(-1) IPA where an increase in IPA concentration to 38 g l(-1) caused reduction in bead integrity. A modified growth medium was developed which allowed repeated use of the beads for more than 42 days without any loss of integrity and continued bioconversion activity.

  19. Alginate hydrogel-mediated crystallization of calcium carbonate

    SciTech Connect

    Ma, Yufei; Feng, Qingling

    2011-05-15

    We documented a specific method for combining calcium ions and alginate molecules slowly and continuously in the mineralization system for the purpose of understanding the mediating function of alginate on the crystallization of calcium carbonate. The alginate was involved in the nucleation and the growth process of CaCO{sub 3}. The crystal size, morphology and roughness of crystal surface were significantly influenced by the type of the alginate, which could be accounted for by the length of the G blocks in alginate. A combination of Fourier transform infrared spectroscopy and thermogravimetric analysis showed that there were the chemical interactions between the alginate and the mineral phase. This strategic approach revealed the biologically controlled CaCO{sub 3} mineralization within calcium alginate hydrogels via the selective nucleation and the confined crystallization of CaCO{sub 3}. The results presented here could contribute to the understanding of the mineralization process in hydrogel systems. -- Graphical abstract: Schematic illustration of the growth of calcite aggregates with different morphologies obtained from (a) Low G alginate gels and (b) High G alginate gels. Display Omitted highlights: > We use a specific method for combining calcium ions and alginate molecules slowly and continuously in the mineralization system to understand the mediating function of alginate on the crystallization of CaCO{sub 3} crystals. > The crystal size, morphology and crystal surface roughness are influenced by the length of G blocks in alginate. There are chemical interactions between the alginate and the mineral phase. > We propose a potential mechanism of CaCO{sub 3} crystallization within High G and Low G calcium alginate hydrogel.

  20. Comparison of non-magnetic and magnetic beads in bead-based assays.

    PubMed

    Hansenová Maňásková, Silvie; van Belkum, Alex; Endtz, Hubert P; Bikker, Floris J; Veerman, Enno C I; van Wamel, Willem J B

    2016-09-01

    Multiplex bead-based flow cytometry is an attractive way for simultaneous, rapid and cost-effective analysis of multiple analytes in a single sample. Previously, we developed various bead-based assays using non-magnetic beads coated with Staphylococcus aureus and Streptococcus pneumoniae antigens for the detection of antibodies. Here, we compared the performance of the assay using non-magnetic beads with one based on the newly developed magnetic beads. We optimized the magnetic beads' coupling procedure and antibody detection assays for S. aureus and S. pneumoniae antigens and we measured IgG in human pooled serum against a series of S. aureus and S. pneumoniae-derived antigens in a singleplex and in a multiplex assay, respectively. For the multiplex assay, the comparison between magnetic and non-magnetic beads showed: i) in the majority of the cases (13 of the 17 tested S. pneumoniae antigens) significantly higher Median Fluorescence Intensity (MFI) values, ii) lower detection limits, iii) lower coefficient of variation (CV: 12% vs. 7% for non-magnetic vs. magnetic beads), so lower inter-assay variation and hence higher reproducibility. Magnetic bead coupling is cost effective, as we used 25% of the normal amount of antigen and only 50% of the beads in comparison to the non-magnetic beads. This optimized magnetic-based assay, which combines ease of use with an improved assay performance, allows detection of antibodies with a low titer that are potentially missed with the non-magnetic-based assay. PMID:27296810

  1. Improving stability and biocompatibility of alginate/chitosan microcapsule by fabricating bi-functional membrane.

    PubMed

    Zheng, Guoshuang; Liu, Xiudong; Wang, Xiuli; Chen, Li; Xie, Hongguo; Wang, Feng; Zheng, Huizhen; Yu, Weiting; Ma, Xiaojun

    2014-05-01

    Cell encapsulation technology holds promise for the cell-based therapy. But poor mechanical strength and biocompatibility of microcapsule membrane are still obstacles for the clinical applications. A novel strategy is presented to prepare AC₁ C₂ A microcapsules with bi-functional membrane (that is, both desirable biocompatibility and membrane stability) by sequentially complexing chitosans with higher deacetylation degree (C₁) and lower deacetylation degree (C₂) on alginate (A) gel beads. Both in vitro and in vivo evaluation of AC₁C₂ A microcapsules demonstrate higher membrane stability and less cell adhesion, because the introduction of C₂ increases membrane strength and decreases surface roughness. Moreover, diffusion test of AC₁C₂ A microcapsules displays no inward permeation of IgG protein suggesting good immunoisolation function. The results demonstrate that AC₁C₂ A microcapsules with bi-functional membrane could be a promising candidate for microencapsulated cell implantation with cost effective usage of naturally biocompatible polysaccharides.

  2. Surface modified alginate microcapsules for 3D cell culture

    NASA Astrophysics Data System (ADS)

    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.

  3. 21 CFR 184.1133 - Ammonium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prepared by the neutralization of purified alginic acid with appropriate pH control agents. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 18, which is incorporated... food Maximum level of use in food (as served) (percent) Functional use Confections, frostings, §...

  4. 21 CFR 184.1133 - Ammonium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...: Category of food Maximum level of use in food (as served) (percent) Functional use Confections, frostings... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium alginate. 184.1133 Section 184.1133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  5. 21 CFR 184.1133 - Ammonium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  6. High-rate ferrous iron oxidation by immobilized Acidithiobacillus ferrooxidans with complex of PVA and sodium alginate.

    PubMed

    Yujian, Wang; Xiaojuan, Yang; Wei, Tu; Hongyu, Li

    2007-02-01

    By four different methods, Acidithiobacillus ferrooxidans cells were immobilized by the complex of PVA and sodium alginate. The beads formed by these different methods were evaluated in terms of relative mechanical strength, biological activity, dilatability, and so on. The results indicate that the technique utilizing the complex of PVA and sodium alginate crosslinked with Ca(NO(3))(2) is more appropriate for the immobilization of A. ferrooxidans than any others. So the PVA-calcium nitrate beads were used in batch and continuous culture. A maximum ferrous iron oxidation rate of 4.6 g/l/h was achieved in batch culture. Long-time performance of packed-bed bioreactor was evaluated systematically over 40 days, depending on the conversion ratio of ferrous iron and the residence time. At a residence time of 2.5 h, 96% of the initial ferrous iron was oxidized. This study shows this new immobilization technique will be a feasible and economical method for A. ferrooxidans.

  7. Immobilization of cellulase from newly isolated strain Bacillus subtilis TD6 using calcium alginate as a support material.

    PubMed

    Andriani, Dian; Sunwoo, Changshin; Ryu, Hwa-Won; Prasetya, Bambang; Park, Don-Hee

    2012-01-01

    Bacillus subtilis TD6 was isolated from Takifugu rubripes, also known as puffer fish. Cellulase from this strain was partially purified by ammonium sulphate precipitation up to 80% saturation, entrapped in calcium alginate beads, and finally characterized using CMC as the substrate. For optimization, various parameters were observed, including pH maximum, temperature maximum, sodium alginate, and calcium chloride concentration. pH maximum of the enzyme showed no changes before and after immobilization and remained stable at 6.0. The temperature maximum showed a slight increase to 60 °C. Two percent sodium alginate and a 0.15 M calcium chloride solution were the optimum conditions for acquisition of enzyme with greater stability. K (m) and V (max) values for the immobilized enzyme were slightly increased, compared with those of free enzyme, 2.9 mg/ml and 32.1 μmol/min/mL, respectively. As the purpose of immobilization, reusability and storage stability of the enzyme were also observed. Immobilized enzyme retained its activity for a longer period of time and can be reused up to four times. The storage stability of entrapped cellulase at 4 °C was found to be up to 12 days, while at 30 °C, the enzyme lost its activity within 3 days.

  8. Production of BCG alginate-PLL microcapsules by emulsification/internal gelation.

    PubMed

    Esquisabel, A; Hernández, R M; Igartua, M; Gascón, A R; Calvo, B; Pedraz, J L

    1997-01-01

    A biocompatible emulsification method for microencapsulation of live cells and enzymes within a calcium alginate matrix applied to Bacillus Calmette-Guérin (BCG) has been developed. Small-diameter alginate beads (microcapsules) were formed via internal gelation of an alginate solution emulsified within vegetable oil. Five different oils (sesame, sweet almond, perhydrosqualene, camomile and jojoba) were used. The rheological analysis of the oils showed a Newtonian behaviour, with viscosities = 30.0, 37.7, 51.2, 59.3 and 67.1 mPa.s for perhydrosqualene, jojoba, camomile, sesame and sweet almond oil respectively. The particle size of the microcapsules obtained ranged from 30.3 microns for the microcapsules prepared with sweet almond oil to 57.0 microns for those made with perhydrosqualene. The mean particle diameter obtained was found to be dependent on the viscosity of the oil employed, according to the equation: phi (micron) = 76.6-0.628 eta (mPa.s) (r2 = 0.943). The encapsulated BCG was identified by the Difco TB stain set K, followed by observation under optical microscopy. Freeze-drying of the microcapsules was carried out to ensure their stability during storage. Two batches of microcapsules (those prepared with sesame and jojoba oil) and four types of cryoprotectors (glucose, trehalose, mannitol and sorbitol), at three concentration levels (5, 10 and 20% w/v) were studied. The parameters evaluated were particle size, physical appearance, reconstitution of lyophilizates and microscopical evaluation. For both batches of microcapsules the best results were obtained with trehalose 5%, showing particle sizes of 42.1 microns in the case of the microcapsules prepared with sesame oil, and of 45.3 microns for those prepared with jojoba.

  9. The secretome of alginate-encapsulated limbal epithelial stem cells modulates corneal epithelial cell proliferation.

    PubMed

    Wright, Bernice; Hopkinson, Andrew; Leyland, Martin; Connon, Che J

    2013-01-01

    Limbal epithelial stem cells may ameliorate limbal stem cell deficiency through secretion of therapeutic proteins, delivered to the cornea in a controlled manner using hydrogels. In the present study the secretome of alginate-encapsulated limbal epithelial stem cells is investigated. Conditioned medium was generated from limbal epithelial stem cells encapsulated in 1.2% (w/v) calcium alginate gels. Conditioned medium proteins separated by 1-D gel electrophoresis were visualized by silver staining. Proteins of interest including secreted protein acidic and rich in cysteine, profilin-1, and galectin-1 were identified by immunoblotting. The effect of conditioned medium (from alginate-encapsulated limbal epithelial stem cells) on corneal epithelial cell proliferation was quantified and shown to significantly inhibit (P≤0.05) their growth. As secreted protein acidic and rich in cysteine was previously reported to attenuate proliferation of epithelial cells, this protein may be responsible, at least in part, for inhibition of corneal epithelial cell proliferation. We conclude that limbal epithelial stem cells encapsulated in alginate gels may regulate corneal epithelialisation through secretion of inhibitory proteins.

  10. Alginate-whey protein granular microspheres as oral delivery vehicles for bioactive compounds.

    PubMed

    Chen, Lingyun; Subirade, Muriel

    2006-09-01

    Alginate (AL)-whey protein isolate (WPI) microspheres of varied WPI/AL ratio, particle diameter and concentration of polymer bead forming solution (C(AL+WPI)) were prepared in order to develop a biocompatible vehicle for oral administration of bioactive compounds. Microscopy revealed a special matrix/granular structure for microspheres with a WPI/AL ratio of 8:2, 100 microm diameter and C(AL+WPI) of 5% (AL-WPI A2), featuring WPI granules 3-10 microm in diameter homogeneously distributed within an AL spherical matrix. The compound release properties of these microspheres were investigated in simulated gastric and intestinal fluids (SGF and SIF). They demonstrated the desirable property of retarding riboflavin release in SGF and underwent alginate matrix erosion together with liberation of WPI granules in SIF, followed by complete release of the riboflavin. Riboflavin release in SGF and in SIF without pancreatin followed the Higuchi diffusion model while release in SIF in the presence of pancreatin was attributed to WPI granule degradation.

  11. Interactions between Chitosan and Alginate Dialdehyde Biopolymers and Their Layer-by-Layer Assemblies.

    PubMed

    Aston, Robyn; Wimalaratne, Medini; Brock, Aidan; Lawrie, Gwendolyn; Grøndahl, Lisbeth

    2015-06-01

    Biopolymers are researched extensively for their applications in biomaterials science and drug delivery including structures and complexes of more than one polymer. Chemical characterization of complexes formed between chitosan (CHI) and alginate dialdehyde (ADA) biopolymers established that while electrostatic interactions dominate (as determined from X-ray photoelectron spectroscopy (XPS)) covalent cross-linking between these biopolymers also contribute to their stability (evidenced from immersion in salt solution). It was furthermore found that imine bond formation could not be directly detected by any of the techniques XPS, FTIR, (1)H NMR, or fluorescence. The layer-by-layer assemblies of the biopolymers formed on silica colloids, glass slides, and alginate hydrogel beads were evaluated using XPS, as well as zeta potential measurements for the silica colloids and changes to hydration properties for the hydrogels. It was found that the degree of oxidation of ADA affected the LbL assemblies in terms of a greater degree of CHI penetration observed when using the more conformationally flexible biopolymer ADA (higher degree of oxidation).

  12. Alginate composites for bone tissue engineering: a review.

    PubMed

    Venkatesan, Jayachandran; Bhatnagar, Ira; Manivasagan, Panchanathan; Kang, Kyong-Hwa; Kim, Se-Kwon

    2015-01-01

    Bone is a complex and hierarchical tissue consisting of nano hydroxyapatite and collagen as major portion. Several attempts have been made to prepare the artificial bone so as to replace the autograft and allograft treatment. Tissue engineering is a promising approach to solve the several issues and is also useful in the construction of artificial bone with materials including polymer, ceramics, metals, cells and growth factors. Composites consisting of polymer-ceramics, best mimic the natural functions of bone. Alginate, an anionic polymer owing enormous biomedical applications, is gaining importance particularly in bone tissue engineering due to its biocompatibility and gel forming properties. Several composites such as alginate-polymer (PLGA, PEG and chitosan), alginate-protein (collagen and gelatin), alginate-ceramic, alginate-bioglass, alginate-biosilica, alginate-bone morphogenetic protein-2 and RGD peptides composite have been investigated till date. These alginate composites show enhanced biochemical significance in terms of porosity, mechanical strength, cell adhesion, biocompatibility, cell proliferation, alkaline phosphatase increase, excellent mineralization and osteogenic differentiation. Hence, alginate based composite biomaterials will be promising for bone tissue regeneration. This review will provide a broad overview of alginate preparation and its applications towards bone tissue engineering.

  13. Chloride Cotransporters as a Molecular Mechanism underlying Spreading Depolarization-Induced Dendritic Beading

    PubMed Central

    Steffensen, Annette B.; Sword, Jeremy; Croom, Deborah

    2015-01-01

    Spreading depolarizations (SDs) are waves of sustained neuronal and glial depolarization that propagate massive disruptions of ion gradients through the brain. SD is associated with migraine aura and recently recognized as a novel mechanism of injury in stroke and brain trauma patients. SD leads to neuronal swelling as assessed in real time with two-photon laser scanning microscopy (2PLSM). Pyramidal neurons do not express aquaporins and thus display low inherent water permeability, yet SD rapidly induces focal swelling (beading) along the dendritic shaft by unidentified molecular mechanisms. To address this issue, we induced SD in murine hippocampal slices by focal KCl microinjection and visualized the ensuing beading of dendrites expressing EGFP by 2PLSM. We confirmed that dendritic beading failed to arise during large (100 mOsm) hyposmotic challenges, underscoring that neuronal swelling does not occur as a simple osmotic event. SD-induced dendritic beading was not prevented by pharmacological interference with the cytoskeleton, supporting the notion that dendritic beading may result entirely from excessive water influx. Dendritic beading was strictly dependent on the presence of Cl−, and, accordingly, combined blockade of Cl−-coupled transporters led to a significant reduction in dendritic beading without interfering with SD. Furthermore, our in vivo data showed a strong inhibition of dendritic beading during pharmacological blockage of these cotransporters. We propose that SD-induced dendritic beading takes place as a consequence of the altered driving forces and thus activity for these cotransporters, which by transport of water during their translocation mechanism may generate dendritic beading independently of osmotic forces. SIGNIFICANCE STATEMENT Spreading depolarization occurs during pathological conditions such as stroke, brain injury, and migraine and is characterized as a wave of massive ion translocation between intracellular and extracellular

  14. Raman probing of molecular interactions of alginate biopolymers with cells

    NASA Astrophysics Data System (ADS)

    Chourpa, Igor; Carpentier, Philippe; Maingault, Philippe; Fetissoff, Franck; Dubois, Pierre

    2000-05-01

    The biological polymers extracted from brown algae, alginates, are novel materials in biotechnology and biomedicine. Their ability to form viscous gels is used to immobilize or encapsulate yeast, enzymes, living cells and drugs. Calcium-alginate fibers are extensively used in wound dressings since exhibit antihaemostatic and healing properties. The problem with alginate-made dressings in surgery is their slow biodegradability: if entrapped within tissues, they can induce a local cellular recruitment with an inflammatory response contemporaneous to the resorption phase. In part, this problem is a consequence of poor solubility of the calcium alginates in water. Although calcium alginate fibers can exchange calcium ions with sodium ions from the wound exudate to create a calcium/sodium alginate fibers, the residual alginates are thought to be not totally degradable in vivo. Rapid and non- destructive characterization of series of the crude alginates and calcium alginate fibers has been performed using Raman spectroscopy with near IR excitation. Study of structural organization of the polymeric chains within calcium alginate fibers have been previously reported as made by confocal Raman multispectral imaging (CRMSI) in visible. Here, the Raman approach has been used to monitor the ion exchange reactions for different types of alginates and their salts in vitro. For in vivo evaluation, histological sections of alginate-treated rat tissue have been analyzed by light microscopy and CRMSI. The in vitro Raman modeling and the histochemical mapping were a necessary precursor for application of the Raman microprobe to follow in a non-invasive way the alginate-cell molecular interactions in rat tissue.

  15. Calibration beads containing luminescent lanthanide ion complexes

    NASA Astrophysics Data System (ADS)

    Leif, Robert C.; Jin, Dayong; Piper, James; Vallarino, Lidia M.; Williams, John W.; Yang, Sean; Zucker, Robert M.

    2008-02-01

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including microscopes. Methods: 0.5, 3, and 5 micron (µm) beads containing a luminescent europium-complex were manufactured and the luminescence distribution of the 5 µm beads was measured with a time-delayed luminescence flow cytometer and a timedelayed digital microscope. The distribution of the luminescence intensity from the europium-complex in individual beads was determined on optical sections by confocal microscopy. The emission spectra of the beads under UV excitation were determined with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation were measured under LED excitation with a fluorescence microscope. Results: The kinetics of UV bleaching were very similar for the 0.5, 3, and 5 µm beads. Emission peaks were found at 592, 616, and 685 nanometers (nm). The width of the principal peak at half-maximum (616 nm) was 9.9 nm. The luminescence lifetimes in water and in air were 340 and 460 microseconds (µs), respectively. The distribution of the europium- complex in the beads was homogeneous. Conclusions: The 5 µm beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells.

  16. Cellobiose hydrolysis using Pichia etchellsii cells immobilized in calcium alginate

    SciTech Connect

    Jain, D.; Ghose, T.K.

    1984-01-01

    The rate of cellulose degradation, limited by inhibition by cellobiose, can be increased by hydrolysis of cellobiose to glucose using immobilized ..beta..-glucosidase. Production of ..beta..-glucosidase in four yeasts was studied and a maximum activity of 1.22 IU/mg cells was obtained in cells of Pichia etchellsii when grown on 3% cellobiose as the sole carbon source. Immobilization of ..beta..-glucosidase containing cells of Pichia etchellsii on various solid supports was conducted and immobilization by entrapment in calcium alginate gel beads was found to be the most simple and efficient method. The immobilized preparation was found to be limited by pore diffusion but exhibited no film-diffusion resistance during packed bed reactor operation. Good plug flow characteristics were observed in the packed bed column indicated by a low dispersion number of 0.1348. A model for reaction with pore diffusion for a noncompetitive type of inhibited system was developed and applied to the cellobiose hydrolysis system. The rate of reaction with diffusional limitations was determined by using the model and effectiveness factors were calculated for different particle sizes. An effectiveness factor of 0.49 was obtained for a particle diameter of 2.5 mm. The modified rate expression using the effectiveness factor represented batch and packed bed reactor operation satisfactorily. The productivity in the packed bed column was found to fall rapidly with increase in conversion rate indicating that the operating conditions of the column would have to be a compromise between high conversion rates and reasonable productivity. A half-life of over seven days was obtained at the operating temperature of 45/sup 0/C in continuous operation of the packed bed reactor. However, the half-life in the column was found to be greatly affected by temperature, increasing to over seve

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

    PubMed Central

    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. PMID:27176711

  18. Antibacterial Performance of Alginic Acid Coating on Polyethylene Film

    PubMed Central

    Karbassi, Elika; Asadinezhad, Ahmad; Lehocký, Marian; Humpolíček, Petr; Vesel, Alenka; Novák, Igor; Sáha, Petr

    2014-01-01

    Alginic acid coated polyethylene films were examined in terms of surface properties and bacteriostatic performance against two most representative bacterial strains, that is, Escherichia coli and Staphylococcus aureus. Microwave plasma treatment followed by brush formation in vapor state from three distinguished precursors (allylalcohol, allylamine, hydroxyethyl methacrylate) was carried out to deposit alginic acid on the substrate. Surface analyses via various techniques established that alginic acid was immobilized onto the surface where grafting (brush) chemistry influenced the amount of alginic acid coated. Moreover, alginic acid was found to be capable of bacterial growth inhibition which itself was significantly affected by the brush type. The polyanionic character of alginic acid as a carbohydrate polymer was assumed to play the pivotal role in antibacterial activity. The cell wall composition of two bacterial strains along with the substrates physicochemical properties accounted for different levels of bacteriostatic performance. PMID:25196604

  19. Antibacterial performance of alginic acid coating on polyethylene film.

    PubMed

    Karbassi, Elika; Asadinezhad, Ahmad; Lehocký, Marian; Humpolíček, Petr; Vesel, Alenka; Novák, Igor; Sáha, Petr

    2014-01-01

    Alginic acid coated polyethylene films were examined in terms of surface properties and bacteriostatic performance against two most representative bacterial strains, that is, Escherichia coli and Staphylococcus aureus. Microwave plasma treatment followed by brush formation in vapor state from three distinguished precursors (allylalcohol, allylamine, hydroxyethyl methacrylate) was carried out to deposit alginic acid on the substrate. Surface analyses via various techniques established that alginic acid was immobilized onto the surface where grafting (brush) chemistry influenced the amount of alginic acid coated. Moreover, alginic acid was found to be capable of bacterial growth inhibition which itself was significantly affected by the brush type. The polyanionic character of alginic acid as a carbohydrate polymer was assumed to play the pivotal role in antibacterial activity. The cell wall composition of two bacterial strains along with the substrates physicochemical properties accounted for different levels of bacteriostatic performance. PMID:25196604

  20. Automated bead alignment apparatus using a single bead capturing technique for fabrication of a miniaturized bead-based DNA probe array.

    PubMed

    Noda, Hideyuki; Kohara, Yoshinobu; Okano, Kazunori; Kambara, Hideki

    2003-07-01

    We have developed an automated bead alignment apparatus for fabricating a bead-based DNA probe array inside a capillary. The apparatus uses 16 micro vacuum tweezers to extract single beads from among a large amount of beads in bead stock wells. It then manipulates single beads into the probe array capillaries. Single 100-microm-diameter beads were successfully extracted from the water-contained bead-stock well by the vacuum tweezers, which have inner and outer diameters of 50 and 150 microm. An interesting aspect is that unexpected extra beads adsorbed on the outer wall of the vacuum tweezers can be removed using the surface tension force between the water and the atmosphere. In testing the total performance of this apparatus, the DNA probe arrays with 10 sets of probe-conjugated beads and 2 plain beads were produced in the intended order in the capillaries. The time needed to align the 12 beads was 10 min, and the 16 bead arrays were fabricated simultaneously. After hybridization experiments using these fabricated DNA probe arrays, fluorescence from each bead was clearly observed.

  1. Beads + String = Atoms You Can See.

    ERIC Educational Resources Information Center

    Hermann, Christine K. F.

    1998-01-01

    Presents hands-on activities that give students a head start in learning the vocabulary and basic theory involved in understanding atomic structure. Uses beads to represent protons, neutrons, and electrons and string to represent orbitals. (DDR)

  2. On-chip magnetic separation of superparamagnetic beads for integrated molecular analysis

    NASA Astrophysics Data System (ADS)

    Florescu, Octavian; Wang, Kevan; Au, Patrick; Tang, Jimmy; Harris, Eva; Beatty, P. Robert; Boser, Bernhard E.

    2010-03-01

    We have demonstrated a postprocessed complementary metal oxide semiconductor (CMOS) integrated circuit (IC) capable of on-chip magnetic separation, i.e., removing via magnetic forces the nonspecifically bound magnetic beads from the detection area on the surface of the chip. Initially, 4.5 μm wide superparamagnetic beads sedimenting out of solution due to gravity were attracted to the detection area by a magnetic concentration force generated by flowing current through a conductor embedded in the IC. After sedimentation, the magnetic beads that did not bind strongly to the functionalized surface of the IC through a specific biochemical complex were removed by a magnetic separation force generated by flowing current through another conductor placed laterally to the detection area. As the spherical bead pivoted on the surface of the chip, the lateral magnetic force was further amplified by mechanical leveraging, and 50 mA of current flowing through the separation conductor placed 18 μm away from the bead resulted in 7.5 pN of tensile force on the biomolecular tether immobilizing the bead. This force proved high enough to break nonspecific interactions while leaving specific antibody-antigen bonds intact. A sandwich capture immunoassay on purified human immunoglobulin G showed strong correlation with a control enzyme linked immunosorbent assay and a detection limit of 10 ng/ml or 70 pM. The beads bound to the detection area after on-chip magnetic separation were detected optically. To implement a fully integrated molecular diagnostics platform, the on-chip magnetic separation functionality presented in this work can be readily combine with state-of-the art CMOS-based magnetic bead detection technology.

  3. Optical diamagnetic biosensor for immunocomplexes on beads

    NASA Astrophysics Data System (ADS)

    Norina, Svetlana B.

    2000-12-01

    In the present work, diamagnetic separation parameters for the porous beads are studied using optical video recording microscopy. The possible direct amount determination of single or double macromolecular layers immobilized in the meshes of the porous beads is demonstrated for the concentrations' range used in heterogenic immunotest and the affinity chromatography, where the direct rapid detection of ligands within sorbent particles is known to be the actual task. A gradient diamagnetic biosensor is described as suitable for rapid quantitative detection of single or double macromolecular layers in porous nonmagnetic beads. Measurements of capture traveling time or accumulation radius in gradient magnetic field have shown that it is possible to determine 0.20 mg/ml of macromolecular amount within several seconds. The portative devices were made on the base of the fabre optic technique to detect accumulation radius of collected beads in two gradient magnetic positions: diamagnetic and paramagnetic zones of magnetized wire with 55 μm in diameter and to registrate with a lot of fabre wires having 30 μm in diameters. The successive procedures of the present method can be described by: the obtaining of agarose immuno-beads, the incubation of beads with the ligand sample or the injection of sample through affinity mini-column, the submerging of the loaded beads into the glass cell containing Ni-wire or the narrow gap of magnetic poles; the computational obtaining of immuno- parameters; binding constants, accumulation radius. Several biotechnological applications of the biosensor are presented on sorbent beads, human lymphocytes.

  4. Using double-poured alginate impressions to fabricate bleaching trays.

    PubMed

    Haywood, V B; Powe, A

    1998-01-01

    Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal. PMID:9656923

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

    PubMed

    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.

  6. Enhancement of cell viability by fabrication of macroscopic 3D hydrogel scaffolds using an innovative cell-dispensing technique supplemented by preosteoblast-laden micro-beads.

    PubMed

    Lee, Hyeongjin; Ahn, Seunghyun; Chun, Wook; Kim, Geunhyung

    2014-04-15

    We propose a new cell-encapsulated dispensing method consisting of hydrogel struts, embedded with cell-laden micro-beads. To develop the scaffolds, we accommodated a three-axis robot dispensing system and aerosol spraying of a cross-linking agent to effect tentative surface gelation of hydrogel alginate struts. To show the feasibility of the method, we used pre-osteoblast (MC3T3-E1) cells. Using this technique, we obtained a reasonable cell viability (>90% after several culture periods) relative to that of a scaffold onto which cells were dispensed in the conventional manner, and successfully fabricated a realistic macroscopic pore-size in a controlled manner with 100% pore-interconnected 3D alginate hydrogel scaffolds of 20 mm × 20 mm × 6 mm.

  7. Redox-responsive alginate microsphere containing cystamine.

    PubMed

    Kwon, Kyeongnan; Kim, Jin-Chul

    2016-10-01

    Redox-responsive microspheres were prepared by solidifying the alginate- and cystamine-containing water droplets of O/W emulsion using calcium ion. Emulsions were prepared using alginate/cystamine mixture solution whose the carboxylic group/the amino group molar ratio was 1:1, 1:2, and 1:3, and whose the total concentration was kept to 2% (w/v). The microspheres on Scanning electron microscopy photographs were almost spherical and they were less than 1 μm in diameter. According to the energy-dispersive X-ray spectroscopy, the sulfur content of the microspheres was found to be 6.1, 11.4, and 14.8% (w/w), respectively, not markedly different from the calculated content. The release degree of blue dextran loaded in the microspheres was higher as the cystamine content was higher. Microspheres released almost the same amount of dye regardless of dithiothreitol (DTT, a reducing agent) concentration when the cystamine content was relatively low (e.g. 14.5% (w/w)), whereas they released dye in DTT concentration-dependent manner when the cystamine content was relatively high (e.g. 27.0 and 35.1% (w/w)). The light scattering intensity of alginate/cystamine mixture solution was stronger at a larger amount of cystamine, indicating that cystamine could cross-link alginate chains. The light scattering intensity decreased with increasing DTT concentration, possibly because of the breakdown of the disulfide bond of cystamine. The breakdown of the disulfide bond could account for why the DTT concentration-dependent release of dye loaded in the microspheres was observed. PMID:27484719

  8. Biodegradation of Methyl Orange by alginate-immobilized Aeromonas sp. in a packed bed reactor: external mass transfer modeling.

    PubMed

    Kathiravan, Mathur Nadarajan; Praveen, Siluvai Antony; Gim, Geun Ho; Han, Gui Hawn; Kim, Si Wouk

    2014-11-01

    Azo dyes are recalcitrant and xenobiotic nature makes these compounds a challenging task for continuous biodegradation up to satisfactorily levels in large-scale. In the present report, the biodegradation efficiency of alginate immobilized indigenous Aeromonas sp. MNK1 on Methyl Orange (MO) in a packed bed reactor was explored. The experimental results were used to determine the external mass transfer model. Complete MO degradation and COD removal were observed at 0.20 cm bead size and 120 ml/h flow rate at 300 mg/l of initial dye concentration. The degradation of MO decreased with increasing bead sizes and flow rates, which may be attributed to the decrease in surface of the beads and higher flux of MO, respectively. The experimental rate constants (k ps) for various beads sizes and flow rates were calculated and compared with theoretically obtained rate constants using external film diffusion models. From the experimental data, the external mass transfer effect was correlated with a model J D = K Re (-(1 - n)). The model was tested with K value (5.7) and the Colburn factor correlation model for 0.20, 0.40 and 0.60 bead sizes were J D = 5.7 Re (-0.15), J D = 5.7 Re (-0.36) and J D = 5.7 Re (-0.48), respectively. Based on the results, the Colburn factor correlation models were found to predict the experimental data accurately. The proposed model was constructive to design and direct industrial applications in packed bed reactors within acceptable limits.

  9. Conditions for efficient on-chip magnetic bead detection via magnetoresistive sensors.

    PubMed

    Albisetti, E; Petti, D; Cantoni, M; Damin, F; Torti, A; Chiari, M; Bertacco, R

    2013-09-15

    A commonly used figure of merit of magnetoresistive sensors employed to detect magnetic beads labeling biomolecules in lab-on-chip applications is the sensor sensitivity (S0) to external magnetic fields in the linear region of the sensor. In this paper we show that, in case of lock-in detection and bead excitation by a small AC magnetic field, S0 is not the good figure of merit to optimize. Indeed, the highest sensitivity to the magnetic beads is achieved biasing the sensor in the region of its characteristics where the product between the DC bias field and the second derivative of the resistance with respect to the magnetic field is maximum. The validity of this criterion, derived from a phenomenological model of bead detection, is proved in case of magnetic tunneling junction sensors detecting magnetic beads with 250nm diameter. This work paves the way to the development of a new generation of sensors properly designed to maximize the bead sensitivity.

  10. Rapid purification of cell encapsulated hydrogel beads from oil phase to aqueous phase in a microfluidic device.

    PubMed

    Deng, Yuliang; Zhang, Nangang; Zhao, Libo; Yu, Xiaolei; Ji, Xinghu; Liu, Wei; Guo, Shishang; Liu, Kan; Zhao, Xing-Zhong

    2011-12-01

    In this paper, we demonstrate a new type of microfluidic chip that can realize continuous-flow purification of hydrogel beads from a carrier oil into aqueous solution by using a laminar-like oil/water interface. The microfluidic chip is composed by two functional components: (1) a flow-focusing bead generation module that can control size and shape of beads, (2) a bead extraction module capable of purifying hydrogel beads from oil into aqueous solution. This module is featured with large branch channels on one side and small ones on the opposite side. Water is continuously infused into the bead extraction module through the large branch channels, resulting in a laminar-like oil/water interface between the branch junctions. Simulation and experimental data show that the efficiency of oil depletion is determined by the relative flow rates between infused water and carrier oil. By using such a microfluidic device, viable cells (HCT116, colon cancer cell line) can be encapsulated in the hydrogel beads and purified into a cell culture media. Significantly improved cell viability was achieved compared to that observed by conventional bead purification approaches. This facile microfluidic chip could be a promising candidate for sample treatment in lab-on-a-chip applications.

  11. The Beads of Translation: Using Beads to Translate mRNA into a Polypeptide Bracelet

    ERIC Educational Resources Information Center

    Dunlap, Dacey; Patrick, Patricia

    2012-01-01

    During this activity, by making beaded bracelets that represent the steps of translation, students simulate the creation of an amino acid chain. They are given an mRNA sequence that they translate into a corresponding polypeptide chain (beads). This activity focuses on the events and sites of translation. The activity provides students with a…

  12. Rapid reagentless quantification of alginate biosynthesis in Pseudomonas fluorescens bacteria mutants using FT-IR spectroscopy coupled to multivariate partial least squares regression.

    PubMed

    Correa, Elon; Sletta, Håvard; Ellis, David I; Hoel, Sunniva; Ertesvåg, Helga; Ellingsen, Trond E; Valla, Svein; Goodacre, Royston

    2012-07-01

    Alginate is an important medical and commercial product and currently is isolated from seaweeds. Certain microorganisms also produce alginate and these polymers have the potential to replace seaweed alginates in some applications, mainly because such production will allow much better and more reproducible control of critical qualitative polymer properties. The research conducted here presents the development of a new approach to this problem by analysing a transposon insertion mutant library constructed in an alginate-producing derivative of the Pseudomonas fluorescens strain SBW25. The procedure is based on the non-destructive and reagent-free method of Fourier transform infrared (FT-IR) spectroscopy which is used to generate a complex biochemical infrared fingerprint of the medium after bacterial growth. First, we investigate the potential differences caused by the growth media fructose and glycerol on the bacterial phenotype and alginate synthesis in 193 selected P. fluorescens mutants and show that clear phenotypic differences are observed in the infrared fingerprints. In order to quantify the level of the alginate we also report the construction and interpretation of multivariate partial least squares regression models which were able to quantify alginate levels successfully with typical normalized root-mean-square error in predictions of only approximately 14%. We have demonstrated that this high-throughput approach can be implemented in alginate screens and we believe that this FT-IR spectroscopic methodology, when combined with the most appropriate chemometrics, could easily be modified for the quantification of other valuable microbial products and play a valuable screening role for synthetic biology.

  13. Aerogel Beads as Cryogenic Thermal Insulation System

    NASA Technical Reports Server (NTRS)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)

    2001-01-01

    An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

  14. A comparative study on liquid core formulation on the diameter on the alginate capsules

    NASA Astrophysics Data System (ADS)

    Ong, Hui-Yen; Lee, Boon-Beng; Radzi, AkmalHadi Ma'; Zakaria, Zarina; Chan, Eng-Seng

    2015-08-01

    Liquid core capsule has vast application in biotechnology related industries such as pharmaceutical, medical, agriculture and food. Formulation of different types of capsule was important to determine the performance of the capsule. Generally, the liquid core capsule with different formulations generated different size of capsule.Therefore, the aim of this project is to investigate the effect of different liquid core solution formulations on the diameter of capsule. The capsule produced by extruding liquid core solutions into sodium alginate solution. Three types of liquid core solutions (chitosan, xanthan gum, polyethylene glycol (PEG)) were investigated. The results showed that there is significant change in capsule diameter despite in different types of liquid core solution were used and a series of capsule range in diameter of 3.1 mm to 4.5 mm were produced. Alginate capsule with chitosan formulation appeared to be the largest capsule among all.

  15. Preparation and characterization of alginate and alginate-resistant starch microparticles containing nisin.

    PubMed

    Hosseini, Seyede Marzieh; Hosseini, Hedayat; Mohammadifar, Mohammad Amin; German, J Bruce; Mortazavian, Amir Mohammad; Mohammadi, Abdorreza; Khosravi-Darani, Kianoosh; Shojaee-Aliabadi, Saeedeh; Khaksar, Ramin

    2014-03-15

    Delivery systems with sustained release of nisin have been proposed to improve stability and long-term effectiveness of this bacteriocin in foods. In this study, nisin was encapsulated in alginate (Alg) and alginate-resistant starch (Alg-RS) microparticles and its release was investigated. Studies found that the nisin concentration has significant influence on encapsulation efficiency (EE), loading capacity (LC) and size of both microparticles. Furthermore, encapsulation efficiency and loading capacity values were more increased by the addition of resistant starch to the alginate formulation. The highest encapsulation efficiency was obtained with Alg-RS microparticles prepared using initial nisin to alginate weight ratio of 25% w/w (59.77 ± 2.26%). Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results confirmed the presence of nisin in the microparticles. The in vitro nisin release from these microparticles followed a controlled-release pattern consistent with a Fickian diffusion mechanism. The release rate from Alg-RS microparticles was less than that from the Alg microparticles.

  16. Maximization of volatile fatty acids production from alginate in acidogenesis.

    PubMed

    Pham, Hong Duc; Seon, Jiyun; Lee, Seong Chan; Song, Minkyung; Woo, Hee-Chul

    2013-11-01

    In this study, the response surface methodology (RSM) was applied to determine the optimum fermentative condition of alginate with the respect to the simultaneous effects of alginate concentration and initial pH to maximize the production of total volatile fatty acids (TVFAs) and alcohols. The results showed that the alginate fermentation was significantly affected by initial pH than by alginate concentration and there was no interaction between the two variables. The optimum condition was 6.2g alginate/L and initial pH 7.6 with a maximum TVFAs yield of 37.1%. Acetic acids were the main constituents of the TVFAs mixtures (i.e., 71.9-95.5%), while alcohols (i.e., ethanol, butanol, and propanol) were not detected.

  17. Biotechnologically produced microbial alginate dressings show enhanced gel forming capacity compared to commercial alginate dressings of marine origin.

    PubMed

    Hoefer, Dirk; Schnepf, Julia K; Hammer, Timo R; Fischer, Melissa; Marquardt, Christoph

    2015-04-01

    Marine alginate fibre dressings are well established in wound management. Alginate fibres can absorb plenty of wound exudate due to their gel forming abilities and ion exchange. Alginates from bacteria have never been studied for medical applications so far, although the microbial polymer raises expectations for improved gelling capacity due to its unique O-acetylation. To prove the gelling capacity of bacterial alginate, we extracted the co-polymer from fermentation of the soil bacterium Azotobacter vinelandii ATCC 9046, cultivated on crude glycerol as an alternative carbon source. Bacterial alginate was isolated in high purity and extruded by a wet spinning method. Fibre structure and properties were characterised by infrared spectroscopy, NMR, GPC, scanning electron microscopy and tensile testing. The fibres could be processed into biocompatible needle web dressings, which showed more than twice the gel formation in saline compared to commercial dressings made of marine alginates. Gelled dressings of bacterial alginate formed stable hydrogels of sufficient shape and strength for wound healing applications. This work suggests that the increased gel formation of bacterial alginate from A. vinelandii may be optimal for the preparation of novel wound dressings.

  18. Coating Layer Characterization of Laser Deposited AlSi Coating over Laser Weld Bead

    NASA Astrophysics Data System (ADS)

    Gu, Hongping; Van Gelder, Aldo

    Corrosion protection of steel components is an important topic in automotive industry. Laser beam welding makes a narrow weld bead, thus minimizing the damage to the original coating on the steel material. However, the weld bead loses its original coating and is vulnerable to corrosive attack. It was demonstrated in this study that laser beam generated AlSi coating is an effective way to apply a protective coating on the weld bead. Coatings with different thickness and topography have been deposited under different laser power and processing speed. The microstructure of the as-deposited coating and its evolution after heat treatment has been studied. EDS was employed to analyze the distribution of chemical compositions of the laser generated coatings. Several metallic compounds of Al and iron have been identified. It was found that the type of metallic compounds can be influenced by the laser processing parameters.

  19. Bead and Process for Removing Dissolved Metal Contaminants

    SciTech Connect

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  20. Superporous agarose beads as a hydrophobic interaction chromatography support.

    PubMed

    Gustavsson, P E; Axelsson, A; Larsson, P O

    1999-01-15

    Superporous agarose beads were used as a support for hydrophobic interaction chromatography. These beads have large connecting flow pores in addition to their normal diffusion pores. The flow pores, which are approximately one fifth of the overall diameter of the superporous agarose beads, were earlier shown to give the beads improved mass transfer properties relative to homogeneous agarose beads (Gustavsson and Larsson, J. Chromatogr. A, 734 (1996) 231-240). Superporous agarose beads and homogeneous agarose beads of the same particle size range (106-180 microns) were derivatized with phenyl groups. The properties of the superporous beads were then compared with the homogeneous beads in the separation of a mixture of three model proteins (ribonuclease A, lysozyme and bovine serum albumin) at various superficial flow velocities from 30 to 600 cm/h. The superporous beads gave satisfactory separation at flow velocities five times higher than was possible for homogeneous beads. The performance of the two types of beads was also compared in the purification of lactate dehydrogenase from a beef heart extract at a superficial flow velocity of 150 cm/h. The superporous beads performed considerably better, leading to twice the purification factor and twice the concentration of the desired product. The results were interpreted using the theoretical treatment given by Carta and Rodrigues (Carta and Rodrigues, Chem. Eng. Sci., 48 (1993) 3927).

  1. Evaluation of sodium alginate as drug release modifier in matrix tablets.

    PubMed

    Liew, Celine Valeria; Chan, Lai Wah; Ching, Ai Ling; Heng, Paul Wan Sia

    2006-02-17

    Alginates are useful natural polymers suitable for use in the design of pharmaceutical dosage forms. However, the effects of particle size, viscosity and chemical composition of alginates on drug release from alginate matrix tablets are not clearly understood. Hence, 17 grades of sodium alginate with different particle size distributions, viscosities and chemical compositions were used to prepare matrix tablets at various concentrations to screen the factors influencing drug release from such matrices. Particle size was found to have an influence on drug release from these matrices. Sodium alginate was subsequently classified into several size fractions and also cryogenically milled to produce smaller particle size samples. Cryogenic milling could be successfully applied to pulverize coarse alginate particles without changing the quality through degradation or segregation. This study showed the significance of each alginate property in modulating drug release: particle size is important in initial alginic acid gel barrier formation as it affected the extent of burst release; higher alginate viscosity slowed down drug release rate in the buffer phase but enhanced release rate in the acid phase; high M-alginate might be more advantageous than high-G-alginate in sustaining drug release; and, the effect of increasing alginate concentration was greater with larger alginate particles. This can serve as a framework for formulators working with alginates. Furthermore, the results showed that sodium alginate matrices can sustain drug release for at least 8 h, even for a highly water-soluble drug in the presence of a water-soluble excipient. PMID:16364576

  2. Wood mimetic hydrogel beads for enzyme immobilization.

    PubMed

    Park, Saerom; Kim, Sung Hee; Won, Keehoon; Choi, Joon Weon; Kim, Yong Hwan; Kim, Hyung Joo; Yang, Yung-Hun; Lee, Sang Hyun

    2015-01-22

    Wood component-based composite hydrogels have potential applications in biomedical fields owing to their low cost, biodegradability, and biocompatibility. The controllable properties of wood mimetic composites containing three major wood components are useful for enzyme immobilization. Here, lipase from Candida rugosa was entrapped in wood mimetic beads containing cellulose, xylan, and lignin by dissolving wood components with lipase in [Emim][Ac], followed by reconstitution. Lipase entrapped in cellulose/xylan/lignin beads in a 5:3:2 ratio showed the highest activity; this ratio is very similar to that in natural wood. The lipase entrapped in various wood mimetic beads showed increased thermal and pH stability. The half-life times of lipase entrapped in cellulose/alkali lignin hydrogel were 31- and 82-times higher than those of free lipase during incubation under denaturing conditions of high temperature and low pH, respectively. Owing to their biocompatibility, biodegradability, and controllable properties, wood mimetic hydrogel beads can be used to immobilize various enzymes for applications in the biomedical, bioelectronic, and biocatalytic fields.

  3. Spring-bead animation of viscoelastic materials.

    PubMed

    Tamura, Nobuhiko; Nakaguchi, Toshiya; Tsumura, Norimichi; Miyake, Yoichi

    2007-01-01

    An interactive animation method for viscoelastic materials builds on Rouse's spring-bead model. Particles are connected one-dimensionally by spring forces to represent single polymer chains. The method approximates the collision's force between particles through the particle density's gradient. This model lets the viscoelasticity be changed dynamically by severing the interconnection of polymer chains. PMID:18027801

  4. In vivo behavior of hydrogel beads based on amidated pectins.

    PubMed

    Munjeri, O; Collett, J H; Fell, J T; Sharma, H L; Smith, A M

    1998-01-01

    Radio-labeled hydrogel beads, based on amidated pectin, have been produced by adding droplets of an amidated pectin solution to calcium chloride. Incorporation of model drugs into the beads and measurement of the dissolution rate showed that the properties of the beads were unaffected by the incorporation of the radiolabel. The labeled beads were used to carry out an in vivo study of their behavior in the gastrointestinal tract using human volunteers. The volunteers were given the beads after an overnight fast and images were obtained at frequent intervals during transit through the upper gastrointestinal tract and the colon. The beads exhibited rapid gastric emptying and proceeded to pass through the small intestine individually before regrouping at the ileo-caecal junction. Once in the colon, the beads again proceeded as individuals and evidence of the degradation of the beads was observed.

  5. Effect of Cellulose Acetate Beads on Interleukin-23 Release.

    PubMed

    Nishise, Shoichi; Abe, Yasuhiko; Nomura, Eiki; Sato, Takeshi; Sasaki, Yu; Iwano, Daisuke; Yoshizawa, Kazuya; Yagi, Makoto; Sakuta, Kazuhiro; Ueno, Yoshiyuki

    2016-08-01

    Interleukin (IL)-23, which is released by activated monocytes and neutrophils, promotes production of high levels of IL-17 by T-helper 17 cells. Cellulose acetate (CA) beads are used as carriers for granulocyte and monocyte (GM) adsorptive apheresis using Adacolumn. Contact between blood and CA beads induces cytokine release; however, their inflammatory effects on IL-23 release are unclear. We aimed to clarify the effect of CA beads on IL-23 release in vitro. We incubated peripheral blood with and without CA beads and measured IL-23. Compared to blood samples incubated without CA beads, blood samples incubated with CA beads had significantly decreased amounts of IL-23. In conclusion, CA beads inhibited IL-23 release from adsorbed GMs. The biological effects of this decrease in IL-23 release during GM adsorption to CA beads need further clarification.

  6. Elemental analysis of bead samples using a laser-induced plasma at low pressure

    NASA Astrophysics Data System (ADS)

    Lie, Tjung Jie; Kurniawan, Koo Hendrik; Kurniawan, Davy P.; Pardede, Marincan; Suliyanti, Maria Margaretha; Khumaeni, Ali; Natiq, Shouny A.; Abdulmadjid, Syahrun Nur; Lee, Yong Inn; Kagawa, Kiichiro; Idris, Nasrullah; Tjia, May On

    2006-01-01

    An Nd:YAG laser (1064 nm, 8 ns, 30 mJ) was focused on various types of fresh, fossilized white coral and giant shell samples, including samples of imitation shell and marble. Such samples are extremely important as material for preparing prayer beads that are extensively used in the Buddhist faith. The aim of this research was to develop a non-destructive method to distinguish original beads from their imitations by means of spectral measurements of the carbon, hydrogen, sodium and magnesium emission intensities and by measuring the hardness of the sample using the ratio between Ca (II) 396.8 nm and Ca (I) 422.6 nm. Based on these measurements, original fresh coral beads can be distinguished from any imitation made from hard wood. The same technique was also effective in distinguishing beads made of shell from its imitation. A spectral analysis of bead was also performed on a fossilized white coral sample and the result can be used to distinguish to some extent the fossilized white coral beads from any imitation made from marble. It was also found that the plasma plume should be generated at low ambient pressure to significantly improve the hydrogen and carbon emission intensity and also to avoid energy loss inside the crater during laser irradiation at atmospheric pressure. The results of this study confirm that operating the laser-induced plasma spectroscopy at reduced ambient pressure offers distinct advantage for bead analysis over the conventional laser-induced breakdown spectroscopy (LIBS) technique operated at atmospheric pressure.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  9. Raman-based imaging uncovers the effects of alginate hydrogel implants in spinal cord injury

    NASA Astrophysics Data System (ADS)

    Galli, Roberta; Tamosaityte, Sandra; Koch, Maria; Sitoci-Ficici, Kerim H.; Later, Robert; Uckermann, Ortrud; Beiermeister, Rudolf; Gelinsky, Michael; Schackert, Gabriele; Kirsch, Matthias; Koch, Edmund; Steiner, Gerald

    2015-07-01

    The treatment of spinal cord injury by using implants that provide a permissive environment for axonal growth is in the focus of the research for regenerative therapies. Here, Raman-based label-free techniques were applied for the characterization of morphochemical properties of surgically induced spinal cord injury in the rat that received an implant of soft unfunctionalized alginate hydrogel. Raman microspectroscopy followed by chemometrics allowed mapping the different degenerative areas, while multimodal multiphoton microscopy (e.g. the combination of coherent anti-Stokes Raman scattering (CARS), endogenous two-photon fluorescence and second harmonic generation on the same platform) enabled to address the morphochemistry of the tissue at cellular level. The regions of injury, characterized by demyelination and scarring, were retrieved and the distribution of key tissue components was evaluated by Raman mapping. The alginate hydrogel was detected in the lesion up to six months after implantation and had positive effects on the nervous tissue. For instance, multimodal multiphoton microscopy complemented the results of Raman mapping, providing the micromorphology of lipid-rich tissue structures by CARS and enabling to discern lipid-rich regions that contained myelinated axons from degenerative regions characterized by myelin fragmentation and presence of foam cells. These findings demonstrate that Raman-based imaging methods provide useful information for the evaluation of alginate implant effects and have therefore the potential to contribute to new strategies for monitoring degenerative and regenerative processes induced in SCI, thereby improving the effectiveness of therapies.

  10. Chitosan-alginate membranes accelerate wound healing.

    PubMed

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

    2015-07-01

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

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

    PubMed

    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 (<50μm) were investigated in this work as carriers for mucosal administration of drugs. Low methoxyl pectin and κ-carrageenan were co-gelled with alginate and further dried with supercritical CO2 (sc-CO2). Spherical mesoporous 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.

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

    PubMed

    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 (<50μm) were investigated in this work as carriers for mucosal administration of drugs. Low methoxyl pectin and κ-carrageenan were co-gelled with alginate and further dried with supercritical CO2 (sc-CO2). Spherical mesoporous aerogel microparticles were obtained for alginate, hybrid alginate/pectin and alginate/κ-carrageenan aerogels, presenting high specific surface area (370-548m(2)g(-1)) and mucoadhesive properties. The microparticles were loaded with ketoprofen via adsorption from its solution in sc-CO2, and with quercetin via supercritical anti-solvent precipitation. Loading of ketoprofen was in the range between 17 and 22wt% whereas quercetin demonstrated loadings of 3.1-5.4wt%. Both the drugs were present in amorphous state. Loading procedure allowed the preservation of antioxidant activity of quercetin. Release of both drugs from alginate/κ-carrageenan aerogel was slightly faster compared to alginate/pectin. The results indicate that alginate-based aerogel microparticles can be viewed as promising matrices for mucosal drug delivery applications. PMID:27393563

  13. An anomalous behavior of trypsin immobilized in alginate network.

    PubMed

    Ganachaud, Chrystelle; Bernin, Diana; Isaksson, Dan; Holmberg, Krister

    2013-05-01

    Alginate is a biopolymer used in drug formulations and for surgical purposes. In the presence of divalent cations, it forms solid gels, and such gels are of interest for immobilization of cells and enzymes. In this work, we entrapped trypsin in an alginate gel together with a known substrate, N α-benzoyl-L-arginine-4-nitroanilide hydrochloride (L-BAPNA), and in the presence or absence of D-BAPNA, which is known to be a competitive inhibitor. Interactions between alginate and the substrate as well as the enzyme were characterized with transmission electron microscopy, rheology, and nuclear magnetic resonance spectroscopy. The biocatalysis was monitored by spectrophotometry at temperatures ranging from 10 to 42 °C. It was found that at 37 and 42 °C a strong acceleration of the reaction was obtained, whereas at 10 °C and at room temperature, the presence of D-BAPNA leads to a retardation of the reaction rate. The same effect was found when the reaction was performed in a non-cross-linked alginate solution. In alginate-free buffer solution, as well as in a solution of carboxymethylcellulose, a biopolymer that resembles alginate, the normal behavior was obtained; however, with D-BAPNA acting as an inhibitor at all temperatures. A more detailed investigation of the reaction kinetics showed that at higher temperature and in the presence of alginate, the curve of initial reaction rate versus L-BAPNA concentration had a sigmoidal shape, indicating an allosteric behavior. We believe that the anomalous behavior of trypsin in the presence of alginate is due to conformational changes caused by interactions between the positively charged trypsin and the strongly negatively charged alginate.

  14. Propagation through alginate encapsulation of axillary buds of Cannabis sativa L. - an important medicinal plant.

    PubMed

    Lata, Hemant; Chandra, Suman; Khan, Ikhlas A; Elsohly, Mahmoud A

    2009-01-01

    Cannabis sativa L. (Cannabaceae) is an important medicinal plant well known for its pharmacologic and therapeutic potency. Because of allogamous nature of this species, it is difficult to maintain its potency and efficacy if grown from the seeds. Therefore, chemical profile-based screening, selection of high yielding elite clones and their propagation using biotechnological tools is the most suitable way to maintain their genetic lines. In this regard, we report a simple and efficient method for the in vitro propagation of a screened and selected high yielding drug type variety of Cannabis sativa, MX-1 using synthetic seed technology. Axillary buds of Cannabis sativa isolated from aseptic multiple shoot cultures were successfully encapsulated in calcium alginate beads. The best gel complexation was achieved using 5 % sodium alginate with 50 mM CaCl2.2H2O. Regrowth and conversion after encapsulation was evaluated both under in vitro and in vivo conditions on different planting substrates. The addition of antimicrobial substance - Plant Preservative Mixture (PPM) had a positive effect on overall plantlet development. Encapsulated explants exhibited the best regrowth and conversion frequency on Murashige and Skoog medium supplemented with thidiazuron (TDZ 0.5 μM) and PPM (0.075 %) under in vitro conditions. Under in vivo conditions, 100 % conversion of encapsulated explants was obtained on 1:1 potting mix- fertilome with coco natural growth medium, moistened with full strength MS medium without TDZ, supplemented with 3 % sucrose and 0.5 % PPM. Plantlets regenerated from the encapsulated explants were hardened off and successfully transferred to the soil. These plants are selected to be used in mass cultivation for the production of biomass as a starting material for the isolation of THC as a bulk active pharmaceutical. PMID:23572915

  15. Improved Enzyme Catalytic Characteristics upon Glutaraldehyde Cross-Linking of Alginate Entrapped Xylanase Isolated from Aspergillus flavus MTCC 9390

    PubMed Central

    Bhushan, Bharat; Pal, Ajay; Jain, Veena

    2015-01-01

    Purified fungal xylanase was entrapped in alginate beads. Its further cross-linking using glutaraldehyde resulted in large enzyme aggregates which may function as both a catalyst and a support material for numerous substrate molecules. Enzyme cross-linking presented a negative impact on enzyme leaching during repeated washings and recovery of enzyme activity was substantial after twelve cycles of usage. The entrapment followed by cross-linking doubled the total bound activity and also greatly improved the enzyme stability at extreme chemical environment. The wide pH stability, better thermo- and storage stability, lowered Km value, and protection from some metal ions are salient achievements of present immobilization. The study shows the efficacy, durability, and sustainability of immobilized catalytic system which could be efficiently used for various juice processing operations. PMID:26347814

  16. Improved production of isomaltulose by a newly isolated mutant of Serratia sp. cells immobilized in calcium alginate.

    PubMed

    Kim, Yonghwan; Koo, Bong-Seong; Lee, Hyeon-Cheol; Yoon, Youngdae

    2015-03-01

    Isomaltulose, also known as palatinose, is produced by sucrose isomerase and has been highlighted as a sugar substitute due to a number of advantageous properties. For the massive production of isomaltulose, high resistance to sucrose and stability of sucrose isomerase as well as sucrose conversion yields would be critical factors. We describe a series of screening procedures to isolate the mutant strain of Serratia sp. possessing enhanced isomaltulose production with improved stability. The new Serratia sp. isolated from a series of screening procedures allowed us to produce isomaltulose from 60% sucrose solution, with over 90% conversion yield. Moreover, when this strain was immobilized in calcium alginate beads and placed in a medium containing 60% sucrose, it showed over 70% sucrose conversion yields for 30 cycles of repeated-batch reactions. Thus, improved conversion activity and stability of the newly isolated Serratia sp. strain in the present study would be highly valuable for industries related to isomaltulose production.

  17. Characterizing Protein Modifications by Reactive Metabolites using Magnetic Bead Bioreactors and LC-MS/MS

    PubMed Central

    Li, Dandan; Fu, You-Jun; Rusling, James F.

    2015-01-01

    We report here label-free metabolite-protein adduct detection and identification employing magnetic beads coated with metabolic enzymes as bioreactors to generate metabolites and possible metabolite-protein adducts for analysis by liquid chromatography-tandem mass spectrometry. PMID:25693065

  18. Chemical modification of alginic acid by ultrasonic irradiation

    NASA Astrophysics Data System (ADS)

    Murdzheva, Dilyana; Denev, Panteley

    2016-03-01

    Abstract: Chemical modification of alginic acid has been done by ultrasonic irradiation to obtain its methylated, ethylated and isopropylated derivatives. The influence of ultrasonic frequency and power on esterification process of alginic acid has been investigated. Alginate derivatives have been characterized by degree of esterification (DE) and IR-FT spectroscopy. It has been found that 45 kHz ultrasonic frequency accelerated modification process as reduced the reaction time from 16 hours to 2 hours. The obtained results showed that ultrasound irradiation increased the reaction efficiency in methanol and depended on the ratio of the M/G.

  19. Metal-Containing Polystyrene Beads as Standards for Mass Cytometry

    PubMed Central

    Abdelrahman, Ahmed I.; Ornatsky, Olga; Bandura, Dmitry; Kinach, Robert; Dai, Sheng; Thickett, Stuart C.; Tanner, Scott

    2010-01-01

    We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells. PMID:20390041

  20. A strategic study using mutant-strain entrapment in calcium alginate for the production of Saccharomyces cerevisiae cells with high invertase activity.

    PubMed

    Rossi-Alva, Juan Carlos; Rocha-Leão, Maria Helena Miguez

    2003-08-01

    Entrapped cells and entrapped cells grown inside of a calcium alginate matrix as well as free cells have been investigated using Saccharomyces cerevisiae mutant strains with regard to their pattern of growth and invertase activity. The repression of invertase by glucose and glucose-consumption ability were considered in the selection process of the mutants. Efficient sucrose bioconversion due to high invertase activity was obtained when entrapped mutant strain Q6R2 cells were grown within calcium alginate gel beads using sucrose plus glucose as the carbon source. Under these conditions, 1 mg (dry weight) of entrapped cells is able to produce 20 micromol of inverted sugar in 3 min (the maximum activity obtained was 20 units x mg(-1)). The experiments were carried out for 6 months without appreciable loss of either bead integrity or invertase activity. The biocatalyst was also stored at 4 degrees C for 6 months without appreciable loss of the invertase activity. This work shows that entrapped yeast cells with a weak ability to consume sugar may be used to produce inverted sugar.