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Sample records for alginate beads generated

  1. A microfluidic manifold with a single pump system to generate highly mono-disperse alginate beads for cell encapsulation

    PubMed Central

    Kim, Choong; Park, Juyoung

    2014-01-01

    Cell encapsulation technology is a promising strategy applicable to tissue engineering and cell therapy. Many advanced microencapsulation chips that function via multiple syringe pumps have been developed to generate mono-disperse hydrogel beads encapsulating cells. However, their operation is difficult and only trained microfluidic engineers can use them with dexterity. Hence, we propose a microfluidic manifold system, driven by a single syringe pump, which can enable the setup of automated flow sequences and generate highly mono-disperse alginate beads by minimizing disturbances to the pump pressure. The encapsulation of P19 mouse embryonic carcinoma cells and embryonic body formation are demonstrated to prove the efficiency of the proposed system. PMID:25587376

  2. Lactococcus lactis release from calcium alginate beads.

    PubMed Central

    Champagne, C P; Gaudy, C; Poncelet, D; Neufeld, R J

    1992-01-01

    Cell release during milk fermentation by Lactococcus lactis immobilized in calcium alginate beads was examined. Numbers of free cells in the milk gradually increased from 1 x 10(6) to 3 x 10(7) CFU/ml upon successive reutilization of the beads. Rinsing the beads between fermentations did not influence the numbers of free cells in the milk. Cell release was not affected by initial cell density within the beads or by alginate concentration, although higher acidification rates were achieved with increased cell loading. Coating alginate beads with poly-L-lysine (PLL) did not significantly reduce the release of cells during five consecutive fermentations. A double coating of PLL and alginate reduced cell release by a factor of approximately 50. However, acidification of milk with beads having the PLL-alginate coating was slower than that with uncoated beads. Immersing the beads in ethanol to kill cells on the periphery reduced cell release, but acidification activity was maintained. Dipping the beads in aluminum nitrate or a hot CaCl2 solution was not as effective as dipping them in ethanol. Ethanol treatment or heating of the beads appears to be a promising method for maintaining acidification activity while minimizing viable cell release due to loosely entrapped cells near the surface of the alginate beads. PMID:1622208

  3. 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.…

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

    PubMed

    Lewandowski, Z; Roe, F

    1994-01-20

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

  5. 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. PMID:17516249

  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. PMID:17964745

  7. 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

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

    PubMed

    Kocaturk, Selin; Yagar, Hulya

    2010-05-01

    Polyphenol oxidase (PPO, EC 1.14.18.1) was isolated from artichoke head (Cynara scolymus L.) by using 0.1 M Tris-HCl buffer (pH 7.0), concentrated by (NH4)2SO4 precipitation, and immobilized in copper-alginate beads. Immobilization yield was determined to be 70%. The cresolase and catecholase activities of enzyme immobilized at optimum immobilization conditions were found to be 13.3 and 670 U g beads min(-1), respectively. Effects of immobilization conditions such as alginate concentration, CaCl2 concentration, amount of loading enzyme, bead size, and amount of beads on enzymatic activity were investigated. Optimum alginate and CuCl2 concentration were found to be 2 % and 3 % (w/v), respectively. Using bead (diameter 3 mm) amount of 0.25 g maximum enzyme activities were observed for both polyphenol activities. The initial concentrations of loading free enzyme were 6.5 U mL(-1) and 5815 U mL(-1) for cresolase activity and catecholase activities, respectively. Beads prepared at optimum immobilization conditions were suitable for up to 8 repeated uses. PMID:20429683

  9. 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

  10. 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

  11. Alginate gel-coated oil-entrapped alginate-tamarind gum-magnesium stearate buoyant beads of risperidone.

    PubMed

    Bera, Hriday; Boddupalli, Shashank; Nandikonda, Sridhar; Kumar, Sanoj; Nayak, Amit Kumar

    2015-01-01

    A novel alginate gel-coated oil-entrapped calcium-alginate-tamarind gum (TG)-magnesium stearate (MS) composite floating beads was developed for intragastric risperidone delivery with a view to improving its oral bioavailability. The TG-blended alginate core beads containing olive oil and MS as low-density materials were accomplished by ionotropic gelation technique. Effects of polymer-blend ratio (sodium alginate:TG) and crosslinker (CaCl2) concentration on drug entrapment efficiency (DEE, %) and cumulative drug release after 8 h (Q8h, %) were studied to optimize the core beads by a 3(2) factorial design. The optimized beads (F-O) exhibited DEE of 75.19±0.75% and Q8h of 78.04±0.38% with minimum errors in prediction. The alginate gel-coated optimized beads displayed superior buoyancy and sustained drug release property. The drug release profiles of the drug-loaded uncoated and coated beads were best fitted in Higuchi kinetic model with Fickian and anomalous diffusion driven mechanisms, respectively. The optimized beads yielded a notable sustained drug release profile as compared to marketed immediate release preparation. The uncoated and coated Ca-alginate-TG-MS beads were also characterized by SEM, FTIR and P-XRD analyses. Thus, the newly developed alginate-gel coated oil-entrapped alginate-TG-MS composite beads are suitable for intragastric delivery of risperidone over a prolonged period of time. PMID:25861741

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

    PubMed

    Jang, L K

    1994-01-20

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

  13. Formulation and drying of alginate beads for controlled release and stabilization of invertase.

    PubMed

    Santagapita, Patricio R; Mazzobre, M Florencia; Buera, M Pilar

    2011-09-12

    Several alternatives to the conventional alginate beads formulation were studied for encapsulation of invertase. Pectin was added to the alginate/enzyme solution while trehalose and β-cyclodextrin were added to the calcium gelation media. The effect of composition changes, freezing, drying methods (freeze, vacuum, or air drying), and thermal treatment were evaluated on invertase stability and its release kinetics from beads. The enzyme release mechanism from wet beads depended on pH. The addition of trehalose, pectin, and β-cyclodextrin modified the bead structure, leading in some cases to a release mechanism that included the relaxation of the polymer chains, besides Fickian diffusion. Enzyme release from vacuum-dried beads was much faster than from freeze-dried beads, probably due to their higher pore size. The inclusion of β-cyclodextrin and especially of pectin prevented enzyme activity losses during bead generation, and trehalose addition was fundamental for achieving adequate invertase protection during freezing, drying, and thermal treatment. Present results showed that several alternatives such as drying method, composition, as well as pH of the relese medium can be managed to control enzyme release. PMID:21809830

  14. Heme Iron Release from Alginate Beads at In Vitro Simulated Gastrointestinal Conditions.

    PubMed

    Valenzuela, Carolina; Hernández, Valesca; Morales, María Sol; Pizarro, Fernando

    2016-07-01

    Heme iron (Fe) release from alginate beads at in vitro simulated gastrointestinal conditions for potential use as oral heme Fe supplement was studied. Five beads at different ratios of sodium alginate (SA)-to-spray-dried bovine blood cells (SDBC) with weight ratios of 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 (w/w) were prepared. Release characteristics of these beads were investigated at in vitro simulated gastrointestinal conditions. Release media pH strongly influenced the controlled Fe release from the beads. The heme Fe-beads in simulated gastric fluid (pH 2) remained in a shrinkage state and Fe release was low: 25.8, 21.1, 11.6, 12.1, and 12.0 % for 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 ratios, respectively. Proportion and amount of Fe released by 1:1.25 and 1:2.5 ratios was higher than the other ratios. The heme Fe-beads swelled and dissociated in simulated intestinal fluid (pH 6), releasing three-fourths of the Fe in 200 min. The morphology studies showed that Fe release followed formation of pores in the alginate matrix, generating erosion of the beads and complete disintegration after 75 and 200 min of gastric and intestinal incubation, respectively. These results indicate that heme Fe-beads may be useful for oral delivery of heme Fe supplement. PMID:26610684

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

    PubMed

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

    1993-03-25

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

  16. 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

  17. 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. PMID:22381372

  18. Ion exchange kinetics of magnetic alginate ferrogel beads produced by external gelation.

    PubMed

    Teixeira, Vânea Ferreira Torres; Pereira, Nádia Rosa; Waldman, Walter Ruggeri; Ávila, Ana Luiza Cassiano Dias; Pérez, Victor Haber; Rodríguez, Rubén Jesus Sánchez

    2014-10-13

    This paper reports on a study of the influence of sodium alginate concentration and iron addition on the ion exchange kinetics of calcium alginate ferrogel beads produced by external gelation. The calcium absorption and sodium release of the beads were fitted to Fick's second law for unsteady state diffusion in order to obtain the effective diffusion coefficients of Na(+) and Ca(2+). The dried beads were characterized concerning their thermal stability, particle size distribution and morphology. The gelation kinetics showed that an increase in alginate concentration from 1% to 2% increased the Ca(2+) equilibrium concentration, but presented no effect on Ca(2+) effective diffusion coefficient. Alginate concentration higher than 2% promoted saturation of binding sites at the bead surfaces. The addition of iron promoted faster diffusion of Ca(2+) inside the gel beads and reduced the Ca(2+) equilibrium concentration. Also, iron particles entrapped in the alginate gel beads promoted greater absorption of water compared to pure alginate gel and lower thermal stability of the beads. The main diffusion of Ca(2+) into and Na(+) out from the bead took place during the first 60 min, during which almost 85-90% of the Ca(2+) equilibrium concentration is achieved, indicating that this period is sufficient to produce a Ca-alginate bead with high crosslinking of the polymer network. PMID:25037343

  19. 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

  20. 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

  1. Simulation of enzyme catalysis in calcium alginate beads.

    PubMed

    Al-Mayah, Ameel M R

    2012-01-01

    A general mathematical model for a fixed bed immobilized enzyme reactor was developed to simulate the process of diffusion and reaction inside the biocatalyst particle. The modeling and simulation of starch hydrolysis using immobilized α-amylase were used as a model for this study. Corn starch hydrolysis was carried out at a constant pH of 5.5 and temperature of 50°C. The substrate flow rate was ranging from 0.2 to 5.0 mL/min, substrate initial concentrations 1 to 100 g/L. α-amylase was immobilized on to calcium alginate hydrogel beads of 2 mm average diameter. In this work Michaelis-Menten kinetics have been considered. The effect of substrate flow rate (i.e., residence time) and initial concentration on intraparticle diffusion have been taken into consideration. The performance of the system is found to be affected by the substrate flow rate and initial concentrations. The reaction is controlled by the reaction rate. The model equation was a nonlinear second order differential equation simulated based on the experimental data for steady state condition. The simulation was achieved numerically using FINITE ELEMENTS in MATLAB software package. The simulated results give satisfactory results for substrate and product concentration profiles within the biocatalyst bead. PMID:23198137

  2. Magnetic Pycnoporus sanguineus-loaded alginate composite beads for removing dye from aqueous solutions.

    PubMed

    Yang, Chih-Hui; Shih, Ming-Cheng; Chiu, Han-Chen; Huang, Keng-Shiang

    2014-01-01

    Dye pollution in wastewater is a severe environmental problem because treating water containing dyes using conventional physical, chemical, and biological treatments is difficult. A conventional process is used to adsorb dyes and filter wastewater. Magnetic filtration is an emerging technology. In this study, magnetic Pycnoporus sanguineus-loaded alginate composite beads were employed to remove a dye solution. A white rot fungus, P. sanguineus, immobilized in alginate beads were used as a biosorbent to remove the dye solution. An alginate polymer could protect P. sanguineus in acidic environments. Superparamagnetic nanomaterials, iron oxide nanoparticles, were combined with alginate gels to form magnetic alginate composites. The magnetic guidability of alginate composites and biocompatibility of iron oxide nanoparticles facilitated the magnetic filtration and separation processes. The fungus cells were immobilized in loaded alginate composites to study the influence of the initial dye concentration and pH on the biosorption capacity. The composite beads could be removed easily post-adsorption by using a magnetic filtration process. When the amount of composite beads was varied, the results of kinetic studies of malachite green adsorption by immobilized cells of P. sanguineus fitted well with the pseudo-second-order model. The results indicated that the magnetic composite beads effectively adsorbed the dye solution from wastewater and were environmentally friendly. PMID:24945580

  3. 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. PMID:25159881

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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. PMID:26485316

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  11. Rifamycins Production by Amycolatopsis mediterranei in Batch and Repeated Batch Cultures Using Immobilized Cells in Alginate and Modified Alginate Beads

    NASA Astrophysics Data System (ADS)

    El-Enshasy, Hesham A.; Beshay, Usama I.; El-Diwany, Ahmed I.; Omar, Hoda M.; El-Kholy, Abdel Ghany E.; El-Najar, Rabab

    The production of rifamycins B and SV by Amycolatopsis mediterranei using immobilization technique was investigated. Alginate beads proved to be an alternative method for the production of rifamycin antibiotic as it has many advantage over using free cells such as it enables the operation at higher dilution rates without the danger of wash out, ease of handling and facilitates recycling or reverse of using microorganism. Different hardening agents were used to improve the stability of the beads and decrease cells escapement. Gum Arabic and gellan gum were used and the rate of rifamycin production increased by using gellan gum as hardening agent compared to pure alginate beads. The rifamycins B and SV increased from 685 to 810 and from 547.5 to 702 mg L-1, respectively by using gellan-gum modified beads compared to the non-treated beads. In repeated batch production, the beads were stable and no breaking of the gel beads was observed throughout the experiment time. The total amount of rifamycin B and SV during the five repeated batches (each of 144 h) reached 3360 and 2309 mg L-1, respectively. On reducing the batch time to only 72 h, the antibiotic production was not influenced and the total concentration of rifamycins B and SV for five batches was 3785 and 2393 mg L-1, respectively.

  12. 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. PMID:18483700

  13. 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

  14. 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. PMID:25149001

  15. 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

  16. Preparation and evaluation of berberine alginate beads for stomach-specific delivery.

    PubMed

    Zhang, Zhen-Hai; Sun, Yong-Shun; Pang, Hui; Munyendo, Were L L; Lv, Hui-Xia; Zhu, Sheng-Liang

    2011-01-01

    The purpose of this research was to prepare floating calcium alginate beads of berberine for targeting the gastric mucosa and prolonging their gastric residence time. The floating beads were prepared by suspending octodecanol and berberine in sodium alginate (SA) solution. The suspension was then dripped into a solution of calcium chloride. The hydrophobic and low-density octodecanol enhanced the sustained-release properties and floating ability of the beads. The bead formulation was optimized for different weight ratios of octodecanol and SA and evaluated in terms of diameter, floating ability and drug loading, entrapment and release. In vitro release studies showed that the floating and sustained release time were effectively increased in gastric media by addition of octodecanol. In vivo studies with rats showed that a significant increase in gastric residence time of beads had been achieved. PMID:22169938

  17. 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

  18. Pullulan-complexed α-amylase and glucosidase in alginate beads: enhanced entrapment and stability.

    PubMed

    Jadhav, Swati B; Singhal, Rekha S

    2014-05-25

    Enhanced entrapment of the enzymes, α-amylase and glucoamylase, was found in alginate beads on addition of pullulan in the enzyme mixture. Under optimized process conditions of entrapment, enzymes-pullulan complex showed an entrapment of 85% in the alginate beads as opposed to 25% for the free enzymes. Beads of enzymes-pullulan complex showed lower inactivation rate constant and higher half life than corresponding beads of free enzymes. Activation energy of beads of enzymes-pullulan was increased by 6.81kJ/mole compared to beads of free enzymes. This implies better stability the enzymes in enzymes-pullulan beads along with increased immobilization yield. Moreover, enzymes-pullulan beads also showed pH stability at extreme acidic and alkaline pH. Addition of pullulan in the enzymes mixture lowered the Km and increased the Vmax as compared to beads of free enzymes. Hydrolysis of starch and reusability study showed better applicability of beads of enzymes-pullulan as compared to free enzymes. PMID:24708951

  19. 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

  20. Preparation and Characterization of Alginate and Psyllium Beads Containing Lactobacillus acidophilus

    PubMed Central

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59 ± 0.04 to 1.67 ± 0.09 mm for ALG and from 1.61 ± 0.06 to 1.80 ± 0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating. PMID:22649306

  1. 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

  2. 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

  3. 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

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

    PubMed

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

    2012-07-01

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

  5. 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

  6. Calcium alginate/dextran methacrylate IPN beads as protecting carriers for protein delivery.

    PubMed

    D'Arrigo, Giorgia; Di Meo, Chiara; Pescosolido, Laura; Coviello, Tommasina; Alhaique, Franco; Matricardi, Pietro

    2012-07-01

    In the present study, mechanical and protein delivery properties of a system based on the interpenetration of calcium-alginate (Ca-Alg) and dextran-methacrylate (Dex-MA) networks are shown. Interpenetrated hydrogels beads were prepared by means of the alginate chains crosslinking with calcium ions, followed by the exposure to UV light that allows the Dex-MA network formation. Optical microscope analysis showed an average diameter of the IPN beads (Ca-Alg/Dex-MA) of 2 mm. This dimension was smaller than that of Ca-Alg beads because of the Dex-MA presence. Moreover, the strength of the IPN beads, and of their corresponding hydrogels, was influenced by the Dex-MA concentration and the crosslinking time. Model proteins (BSA and HRP) were successfully entrapped into the beads and released at a controlled rate, modulated by changing the Dex-MA concentration. The enzymatic activity of HRP released from the beads was maintained. These novel IPN beads have great potential as protein delivery system. PMID:22528076

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

    PubMed

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

    2009-07-30

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

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

    PubMed Central

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

    2014-01-01

    Alginate-based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab-to-lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly-l-lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)-block-poly(l-lysine hydrochloride) (PEG454-b-PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454-b-PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP-1 monocytes was observed with both PLL and PEG454-b-PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties. PMID:23853069

  9. 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. PMID:26592698

  10. Synthesis of magnetic alginate hybrid beads for efficient chromium (VI) removal.

    PubMed

    Gopalakannan, Venkatrajan; Viswanathan, Natrayasamy

    2015-01-01

    Recently magnetic bio-composites have attracted the attention of scientists because of their unique characteristics like selectivity and high sorption capacity. In the present study, Fe3O4@Alg-Ce magnetic composite beads were developed by incorporating Fe3O4 particles onto alginate (Alg) biopolymer followed by cross-linking with Ce(3+) ions. The synthesized magnetic beads were characterized using FTIR and SEM with EDAX analysis and utilized for chromium (VI) removal in batch mode. A comparative adsorption performance of Fe3O4 particles, calcium alginate (CaAlg) composite and Fe3O4@Alg-Ce magnetic hybrid beads was made. The magnetic alginate beads possess an enhanced SC of 14.29 mg/g than CaAlg composite and Fe3O4 particles which possess SC of 9.45 and 9.72 mg/g respectively. The various sorption influencing parameters like contact time, pH, challenger anions, initial chromium concentration and temperature were optimized. The adsorption process was explained using Freundlich and Langmuir isotherms. The sorption kinetics was fitted well with the pseudo second order and intra particle diffusion model. The calculated thermodynamic parameters indicate the nature of chromium sorption is spontaneous and endothermic. PMID:25256552

  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. 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.

  13. Ionically crosslinked alginate-carboxymethyl cellulose beads for the delivery of protein therapeutics

    NASA Astrophysics Data System (ADS)

    Kim, Min Sup; Park, Sang Jun; Gu, Bon Kang; Kim, Chun-Ho

    2012-12-01

    We developed Fe3+-crosslinked alginate-carboxymethyl cellulose (AC) beads in various volume ratios by dropping an AC solution into a ferric chloride solution to form protein therapeutic carrier beads. Scanning electron microscopy revealed that the roughness and pore size of the crosslinked beads increased with the volume ratio of the carboxymethyl cellulose. Fourier transform-infrared analysis revealed the formation of a three-dimensional bonding structure between the anionic polymeric chains of AC and the Fe3+ ions. The degree of swelling and the release profile of albumin from the beads were investigated under simulated gastrointestinal conditions (pH 1.2, 4.5, and 7.4). The Fe3+-crosslinked AC beads displayed different degrees of swelling and albumin release for the various AC volume ratios and under various pH conditions. An in vitro release test was used to monitor the controlled release of albumin from the AC beads under simulated gastrointestinal conditions over 24 h. The Fe3+-crosslinked AC beads protected and controlled the release of protein, demonstrating that such beads present a promising protein therapeutic carrier for the oral delivery.

  14. 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

  15. 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

  16. 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

  17. Magnetite-alginate beads for purification of some starch degrading enzymes.

    PubMed

    Teotia, Sunita; Gupta, M N

    2002-03-01

    Starch degrading enzymes, viz., beta-amylase, glucoamylase, and pullulanase, were purified using magnetite-alginate beads. In each case, the enzyme activity was eluted by using 1.0 M maltose. beta-Amylase (sweet potato), glucoamylase (Aspergillus niger), and pullulanase (Bacillus acidopullulyticus) from their crude preparations were purified 37-, 31-, and 49-fold with 86, 87, and 95% activity recovery, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed single band in each case. PMID:11936253

  18. 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

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

    PubMed

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

    2014-08-01

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

  20. 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. PMID:22734868

  1. 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.

  2. Immobilization of Brassica oleracea chlorophyllase 1 (BoCLH1) and Candida rugosa lipase (CRL) in magnetic alginate beads: an enzymatic evaluation in the corresponding proteins.

    PubMed

    Yang, Chih-Hui; Yen, Chih-Chung; Jheng, Jen-Jyun; Wang, Chih-Yu; Chen, Sheau-Shyang; Huang, Pei-Yu; Huang, Keng-Shiang; Shaw, Jei-Fu

    2014-01-01

    Enzymes have a wide variety of applications in diverse biotechnological fields, and the immobilization of enzymes plays a key role in academic research or industrialization due to the stabilization and recyclability it confers. In this study, we immobilized the Brassica oleracea chlorophyllase 1 (BoCLH1) or Candida rugosa lipase (CRL) in magnetic iron oxide nanoparticles-loaded alginate composite beads. The catalytic activity and specific activity of the BoCLH1 and CRL entrapped in magnetic alginate composite beads were evaluated. Results show that the activity of immobilized BoCLH1 in magnetic alginate composite beads (3.36±0.469 U/g gel) was higher than that of immobilized BoCLH1 in alginate beads (2.96±0.264 U/g gel). In addition, the specific activity of BoCLH1 beads (10.90±1.521 U/mg protein) was higher than that immobilized BoCLH1 in alginate beads (8.52±0.758 U/mg protein). In contrast, the immobilized CRL in magnetic alginate composite beads exhibited a lower enzyme activity (11.81±0.618) than CRL immobilized in alginate beads (94.83±7.929), and the specific activity of immobilized CRL entrapped in magnetic alginate composite beads (1.99±0.104) was lower than immobilized lipase in alginate beads (15.01±1.255). A study of the degradation of magnetic alginate composite beads immersed in acidic solution (pH 3) shows that the magnetic alginate composite beads remain intact in acidic solution for at least 6 h, indicating the maintenance of the enzyme catalytic effect in low-pH environment. Finally, the enzyme immobilized magnetic alginate composite beads could be collected by an external magnet and reused for at least six cycles. PMID:25105918

  3. 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. PMID:26674837

  4. Floating mucoadhesive alginate beads of amoxicillin trihydrate: A facile approach for H. pylori eradication.

    PubMed

    Dey, Sanjoy Kumar; De, Pintu Kumar; De, Arnab; Ojha, Souvik; De, Ronita; Mukhopadhyay, Asish Kumar; Samanta, Amalesh

    2016-08-01

    This study investigates the design of sunflower oil entrapped floating and mucoadhesive beads of amoxicillin trihydrate using sodium alginate and hydroxypropyl methylcellulose as matrix polymers and chitosan as coating polymer to localize the antibiotic at the stomach site against Helicobacter pylori. Beads prepared by ionotropic gellation technique were evaluated for different physicochemical, in-vitro and in-vivo properties. Beads of all batches were floated for >24h with a maximum lag time of 46.3±3.2s. Scanning electron microscopy revealed that the beads were spherical in shape with few oil filled channels distributed throughout the surfaces and small pocket structures inside the matrix confirming oil entrapment. Prepared beads showed good mucoadhesiveness of 75.7±3.0% to 85.0±5.5%. The drug release profile was best fitted to Higuchi model with non fickian driven mechanism. The optimized batch showed 100% Helicobacter pylori growth inhibition in 15h in in-vitro culture. Furthermore, X-ray study in rabbit stomach confirmed the gastric retention of optimized formulation. The results exhibited that formulated beads may be preferred to localize the antibiotic in the gastric region to allow more availability of antibiotic at gastric mucus layer acting on Helicobacter pylori, thereby improving the therapeutic efficacy. PMID:27177460

  5. 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

  6. Effect of gamma radiation on the physico-chemical properties of alginate-based films and beads

    NASA Astrophysics Data System (ADS)

    Huq, Tanzina; Khan, Avik; Dussault, Dominic; Salmieri, Stephane; Khan, Ruhul A.; Lacroix, Monique

    2012-08-01

    Alginate solution (3%, w/v) was prepared using deionized water from its powder. Then the solution was exposed to gamma radiation (0.1-25 kGy). The alginate films were prepared by solution casting. It was found that gamma radiation has strong effect on alginate solution. At low doses, mechanical strength of the alginate films improved but after 5 kGy dose, the strength started to decrease. The mechanism of alginate radiolysis in aqueous solution is discussed. Film formation was not possible from alginate solution at doses >5 kGy. The mechanical properties such as puncture strength (PS), puncture deformation (PD), viscoelasticity (Y) coefficient of the un-irradiated films were investigated. The values of PS, PD and Y coefficient of the films were 333 N/mm, 3.20 mm and 27%, respectively. Alginate beads were prepared from 3% alginate solution (w/v) by ionotropic gelation method in 5% CaCl2 solution. The rate of gel swelling improved in irradiated alginate-based beads at low doses (up to 0.5 kGy).

  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. PMID:26422447

  8. 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

  9. 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

  10. Diffusivity of Cu[sup 2+] in calcium alginate gel beads

    SciTech Connect

    Chen, Dong; Lewandowski, Z.; Roe, F.; Surapaneni, P. )

    1993-03-25

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

  11. 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. PMID:23423649

  12. 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.

  13. 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

  14. 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

  15. Hydrolysis of pullulan by entrapped pullulanase in Ca/alginate beads.

    PubMed

    Gasmi, Sarah Nawel; Rihouey, Christophe; Picton, Luc; Le Cerf, Didier

    2014-09-01

    Pullulanase from Klebsiella pneumoniae was entrapped into calcium alginate beads. Its activity was estimated by the determination of number-average molar masses using two different methods: a colorimetric assay of reducing ends (REs) and a size-exclusion chromatography/multiangle light scattering/differential refractive index. The second method also provided weight-average molar masses of hydrolyzed pullulan and the quantity of maltotriose (DP3) and its multiples (DP6 and DP9) produced by the enzymatic treatment. The alginate beads showed a good retention of the loaded pullulanase (30%), and the system showed a downturn of hydrolysis kinetics in comparison with free pullulanase due to the limiting access of substrate-enzyme. On the contrary with the results obtained from free enzyme hydrolysis, for which a large distribution of pullulan fragments is observed during the treatment, the immobilized enzyme system has evidenced, during the enzymatic treatment, the coexistence of native or only slightly degraded pullulan chains together with maltotriose units. Complete hydrolysis of pullulan chains was achieved once diffused into the gel. PMID:24633755

  16. 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

  17. Calcium-alginate gel bead cross-linked with gelatin as microcarrier for anchorage-dependent cell culture.

    PubMed

    Kwon, Young Jik; Peng, Ching-An

    2002-07-01

    Valuable products obtainedfrom the cultivation of anchorage-dependent mammalian cells require large-scale processes to obtain commercially useful quantities. It is generally accepted that suspension culture is the ideal mode of operation. Because anchorage-dependent cells need surfaces to be able to attach and spread, the incorporation of microcarriers to suspension culture is indispensable. Since the dextran-based microcarrier wasfirst introduced, many different types of microcarriers have been developed and commercialized. In this study, alginate-based microcarriers were made in the following order: (i) calcium-alginate gel beads prepared by dropping a blend of sodium alginate and propylene glycol alginate (PGA) into calcium chloride solution, (ii) the PGA section of gel beads cross-linked with gelatin in alkaline solution (i.e., via the transacylation reaction between the ester group of PGA and amino group of gelatin), and (iii) gelatin membrane around the beads further cross-linked by glutaraldehyde. The glutaraldehyde-treated gelatintransacylated PGA/alginate microcarrier showed superior features in high stability under phosphate-containing solution, density close to that of culture medium, and transparency. Moreover, the Chinese hamster ovary CHO-KI and amphotropic retrovirus producer PA317 cells cultivated on the newly synthesized microcarriers exhibited similar growth kinetics of these two types of cell lines cultured on commercial polystyrene microcarriers. However, cell morphology was easily monitored on the transparent microcarriers made in this study. PMID:12139248

  18. 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. PMID:23360248

  19. 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

  20. Vitreous Cryopreservation of Human Preantral Follicles Encapsulated in Alginate Beads with Mini Mesh Cups

    PubMed Central

    BIAN, Jiang; LI, Tao; DING, Chenhui; XIN, Weijie; ZHU, Bo; ZHOU, Canquan

    2013-01-01

    Abstract To completely avoid ice crystal formation and thus get a higher survival rate, vitrification methods have been commonly used for cryopreservation of oocytes and embryos. However, currently used vitrification methods for oocytes and embryos are not suitable for the cryopreservation of preantral follicles (PFs). In the present study, stainless steel mesh was fabricated into mini mesh cups to vitrify isolated PFs. Moreover, isolated follicles were encapsulated and then subjected to vitreous cryopreservation to facilitate in vitro culture/maturation of follicles after warming. The results showed that the percentages of viable follicles did not differ significantly between the vitrification group and fresh group soon after warming (81.25% vs. 85.29%, P>0.05) and after a 7-day culture period (77.78% vs. 83.33%, P>0.05). No difference in mean follicular diameter was observed between cryopreserved and fresh follicles when cultured in vitro. Transmission electron microscopic analysis revealed that vitreous cryopreservation could maintain the ultrastructure of follicles in alginate beads. In conclusion, the present vitrification method could efficiently cryopreserve isolated human ovarian follicles encapsulated by calcium alginate, which could be put into immediate use (in vitro culture/ maturation) after warming. However, more follicles and some detailed biochemical analyses are required to further investigate the effects of vitrification on the long-term growth of human encapsulated PFs. PMID:23485957

  1. Immobilized metal affinity chromatography without chelating ligands: purification of soybean trypsin inhibitor on zinc alginate beads.

    PubMed

    Gupta, Munishwar N; Jain, Sulakshana; Roy, Ipsita

    2002-01-01

    Immobilized metal affinity chromatography (IMAC) is a widely used technique for bioseparation of proteins in general and recombinant proteins with polyhistidine fusion tags in particular. An expensive and critical step in this process is coupling of a chelating ligand to the chromatographic matrix. This chelating ligand coordinates metal ions such as Cu(2+), Zn(2+), and Ni(2+), which in turn bind proteins. The toxicity of chemicals required for coupling and their slow release during the separation process are of considerable concern. This is an important issue in the context of purification of proteins/enzymes which are used in food processing or pharmaceutical purposes. In this work, a simpler IMAC design is described which should lead to a paradigm shift in the application of IMAC in separation. It is shown that zinc alginate beads (formed by chelating alginate with Zn(2+) directly) can be used for IMAC. As "proof of concept", soybean trypsin inhibitor was purified 18-fold from its crude extract with 90% recovery of biological activity. The dynamic binding capacity of the packed bed was 3919 U mL(-1), as determined by frontal analysis. The media could be regenerated with 8 M urea and reused five times without any appreciable loss in its binding capacity. PMID:11822903

  2. 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.

  3. 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

  4. 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

  5. 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

    2016-03-01

    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

  6. 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. PMID:27372121

  7. Drug release of pH/temperature-responsive calcium alginate/poly(N-isopropylacrylamide) semi-IPN beads.

    PubMed

    Shi, Jun; Alves, Natália M; Mano, João F

    2006-05-23

    A series of semi-interpenetrating, polymer network (semi-IPN), hydrogel beads, composed of calcium alginate (Ca-alginate) and poly(N-isopropylacrylamide) (PNIPAAM), were prepared for a pH/temperature-sensitive drug delivery study. The equilibrium swelling showed the independent pH- and thermo- responsive nature of the developed materials. At pH=2.1, the release amount of indomethacin incorporated into these beads was about 10% within 400 min, while this value approached to 95% at pH=7.4. The release rate of the drug was higher at 37 degrees C than that at 25 degrees C and increased slightly with increasing PNIPAAM content. These results suggest that the Ca-alginate/PNIPAAM beads have the potential to be used as an effective pH/temperature sustainable delivery system of bioactive agents. [GRAPHS: SEE TEXT] A summary of the temperature- and pH-dependence on the release of the drug over a period of 450 min. The effect of the temperature on the swelling of the beads is shown in the inset. PMID:16671051

  8. 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. PMID:27178944

  9. 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

    2016-04-20

    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. PMID:26611443

  10. Guar gum succinate-sodium alginate beads as a pH-sensitive carrier for colon-specific drug delivery.

    PubMed

    Seeli, D Sathya; Dhivya, S; Selvamurugan, N; Prabaharan, M

    2016-10-01

    Guar gum succinate - sodium alginate (GGS-SA) beads cross-linked with barium ions were prepared and characterized as a pH sensitive carrier for colon-specific drug delivery. The structure of GGS-SA beads was confirmed by FT-IR spectroscopy. Scanning Electron Microscope (SEM) studies revealed that the drug loaded GGS-SA beads prepared using 2:2 (w/v) weight percent of GGS and SA had a diameter about 1.4mm and roughly spherical in shape. X-ray diffraction (XRD) studies showed that the peaks corresponding to GGS and SA at 13.5°, 17.5°, 20.2° and 13.5°, 22°, 24.1°, respectively were destroyed in GGS-SA beads which show that these beads are more amorphous in nature. Swelling studies demonstrated the pH-dependent swelling behavior of GGS-SA beads. The beads showed higher swelling degrees in pH 7.4 than that in pH 1.2 due to the existence of anionic groups in the polymer chains. The drug release study showed that the amount of model drug, ibuprofen, released from the GGS-SA beads was higher in pH 7.4 than that in pH 1.2 due to the pH-dependent swelling behavior of the beads. MTT assay revealed that GGS-SA beads at a concentration range of 0-30μg/ml had no cytotoxic effect on the cultured mouse mesenchymal stem cells (C3H10T1/2). These results suggest that GGS-SA beads can be used as effective colon-specific drug delivery system with pH-dependent drug release ability. PMID:27212216

  11. 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

  12. 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

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

    PubMed

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

    2015-11-20

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

  14. 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

  15. Multilayer sodium alginate beads with porous core containing chitosan based nanoparticles for oral delivery of anticancer drug.

    PubMed

    Li, Jing; Jiang, Changqing; Lang, Xuqian; Kong, Ming; Cheng, Xiaojie; Liu, Ya; Feng, Chao; Chen, Xiguang

    2016-04-01

    To develop efficient and safe anticancer drug doxorubicin hydrochloride (DOX) delivery system for oral chemotherapy, chitosan based nanoparticles (CS/CMCS-NPs) composed of chitosan (CS) and o-carboxymeymethy chitosan (CMCS) were immobilized in multilayer sodium alginate beads (NPs-M-Beads). Two kinds of NPs-M-Beads, with or without porous core, were respectively prepared by internal or external ionic gelation method. In the small intestine, the intact CS/CMCS-NPs were able to escape from porous-beads and sustained release the loading DOX. In vivo results showed that the DOX could be efficiently absorbed by small intestine of SD rat and the higher concentration of the DOX in major organs of rats were found after oral administration of Porous-Beads, which were about 2-4 folds higher than that of non-porous-beads. These results suggested that the NPs-M-Beads with porous core to be exciting and promising for oral delivery of DOX. PMID:26724684

  16. 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.

  17. In situ pore-forming alginate hydrogel beads loaded with in situ formed nano-silver and their catalytic activity.

    PubMed

    Wang, Qin; Liu, Shanshan; Wang, Hong; Yang, Yajiang

    2016-05-14

    An aqueous mixture of sodium carbonate (Na2CO3) and sodium alginate (Na-ALG) was added dropwise into an aqueous solution of Ca(NO3)2, leading to the formation of calcium alginate (Ca-ALG) hydrogel beads. Meanwhile Na2CO3 as a pore-forming precursor was transformed in situ into CaCO3 nanoparticles (CaCO3 NPs). SEM images show that CaCO3 NPs aggregates with a size of ∼10 μm were uniformly distributed in the Ca-ALG hydrogel beads. After subsequent erosion using acetic acid, Ca-ALG hydrogel beads with a uniform microporous structure were obtained. The porosity and specific surface area of such in situ pore-formed hydrogel beads are 16 and 14 times higher than those of the beads prepared in the absence of Na2CO3. Additionally, their porous structure can be modulated by varying the amount of Na2CO3. The obtained porous Ca-ALG hydrogel beads were further immersed into an aqueous solution of AgNO3. Under UV irradiation, the Ag(+) ions adsorbed in the Ca-ALG were in situ reduced to Ag nanoparticles (Ag NPs). SEM and TEM images show that Ag NPs with a size of ∼10 nm were uniformly distributed in the matrix of the hydrogel beads. The loading amount of Ag in the beads can also be modulated by varying the amount of Na2CO3. Furthermore, the resultant Ca-ALG beads loaded with Ag NPs (Ag/Ca-ALG) were used as catalysts. Their catalytic activity was evaluated by using the reduction reaction of 4-nitrophenol as a model reaction. The rate constant of the reaction in the presence of dry porous Ag/Ca-ALG beads was found to be 36 times higher than that in the presence of beads prepared in the absence of Na2CO3. Such a high catalytic efficiency can be attributed to their porous structure and consequent high Ag-loading capacity. PMID:27093592

  18. 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. PMID:23881317

  19. 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

  20. 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

  1. Removal of copper(II) from aqueous solution using nanochitosan/sodium alginate/microcrystalline cellulose beads.

    PubMed

    Vijayalakshmi, K; Gomathi, Thandapani; Latha, Srinivasan; Hajeeth, T; Sudha, P N

    2016-01-01

    The present study was aimed to prepare the novel ternary biopolymeric beads of nanochitosan (NCS)/sodium alginate (SA)/microcrystalline cellulose (MC) for the removal of heavy metal copper from aqueous solution through batch adsorption mode. The polymeric beads were characterized before and after adsorption using FTIR, XRD and EDX-SEM studies. The efficiency of the adsorbent was analyzed by varying the parameters such as initial metal ion concentration, contact time, adsorbent dose and pH. The experimental data obtained were fitted in the isotherm models such as Langmuir, Freundlich and Tempkin models and in pseudo first and second order kinetics studies. The isotherm and kinetics models revealed that the adsorption was found to fit well with Freundlich isotherm and follows pseudo second-order kinetics. PMID:26434525

  2. Effect of non-cross-linked calcium on characteristics, swelling behaviour, drug release and mucoadhesiveness of calcium alginate beads.

    PubMed

    Dalaty, Adnan Al; Karam, Ayman; Najlah, Mohammad; Alany, Raid G; Khoder, Mouhamad

    2016-04-20

    In this study, ibuprofen-loaded calcium alginate beads (CABs) with varying amounts of non-cross-linked calcium (NCL-Ca) were prepared using different washing methods. The influence of NCL-Ca on beads properties was investigated. Increasing the number or duration of washes led to significant decreases in the amount of NCL-Ca whereas the impact of the volume of washes was not significant. Approximately 70% of the initial amount of Ca(2+) was NCL-Ca which was removable by washing while only 30% was cross-linked (CL-Ca). Ca(2+) release from the CABs was bimodal; NCL-Ca was burst-released followed by a slower release of CL-Ca. Washing methods and the amount of NCL-Ca had significant influences on the encapsulation efficiency, beads weight, beads swelling, drug release profile and the mucoadhesiveness of CABs. This study highlighted the importance of washing methods and the amount of NCL-Ca to establish CABs properties and understand their behaviour in the simulated intestinal fluids (SIFs). PMID:26876840

  3. 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

  4. 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). PMID:23399273

  5. Kluyveromyces lactis cells entrapped in Ca-alginate beads for the continuous production of a heterologous glucoamylase.

    PubMed

    de Alteriis, Elisabetta; Silvestro, Giovanni; Poletto, Massimo; Romano, Vittorio; Capitanio, Daniele; Compagno, Concetta; Parascandola, Palma

    2004-04-01

    Viable cells of Kluyveromyces lactis, transformed with the glucoamylase gene from Arxula adeninivorans, were entrapped in beads of Ca-alginate and employed on a lab scale in a continuous stirred and a fluidised bed reactor (FBR), both fed with a rich medium (YEP) containing lactose as carbon source. Experiments with freely suspended cells in batch and chemostat had demonstrated that glucoamylase production was favoured in the presence of lactose and YEP medium. Employing controlled-sized beads having a 2.13 mm diameter, specific glucoamylase productivity was higher in the stirred reactor (CSTR) than in the FBR; in the latter a higher volumetric productivity was achieved, due to the lower void degree. The performance of the immobilised cell systems, in terms of specific glucoamylase productivity, was strongly affected by mass transfer limitations occurring throughout the gel due to the high molecular weight of the product. In the perspective to improve and scale-up the immobilised cell system proposed, a mathematical model, which takes into account substrate transfer limitations throughout the gel, has been developed. The effective lactose diffusivity was related to the bead reactive efficiency by means of the Thiele modulus. The regression of the model parameters on the experimental data of substrate consumption obtained both in the CSTR and in the FBR allowed to estimate lactose diffusivity and the kinetic parameters of the immobilised yeast. PMID:15063616

  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. 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

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

    PubMed Central

    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 32 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

  9. 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

  10. Sorptive removal of trivalent and hexavalent chromium from binary aqueous solutions by composite alginate-goethite beads.

    PubMed

    Lazaridis, N K; Charalambous, Ch

    2005-11-01

    In this study, the removal of hexavalent and trivalent chromium ions from binary aqueous solutions by composite alginate-goethite beads was investigated in a batch mode. Equilibrium sorption experiments were carried out at different temperatures and pH values. The data were correlated with Langmuir and Freundlich equations. The thermodynamic parameters calculated were: change in free energy, in enthalpy, in entropy and the heat of adsorption. The influence of mixing rate, sorbent concentration and sorbent particle size was studied at kinetic runs. The effective diffusion coefficients were evaluated by employing the homogeneous diffusion model and the shrinking core model for hexavalent and trivalent chromium, respectively. Desorption experiments were conducted by employing various eluants showed that the loaded material could be regenerated satisfactorily. PMID:16233908

  11. 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

  12. Intermittent hydrostatic pressure maintains and enhances the chondrogenic differentiation of cartilage progenitor cells cultivated in alginate beads.

    PubMed

    Li, Yang; Zhou, Jianxin; Yang, Xiaofei; Jiang, Yiqiu; Gui, Jianchao

    2016-02-01

    The objective of this study was to explore the effects of intermittent hydrostatic pressure (IHP) on the chondrogenic differentiation of cartilage progenitor cells (CPCs) cultivated in alginate beads. CPCs were isolated from the knee joint cartilage of rabbits, and infrapatellar fat pad-derived stem cells (FPSCs) and chondrocytes (CCs) were included as the control cell types. Cells embedded in alginate beads were treated with IHP at 5 Mpa and 0.5 Hz for 4 h/day for 1, 2, or 4 weeks. The cells' migratory and proliferative capacities were evaluated using the scratch and Live/Dead assays, respectively. Hematoxylin and eosin staining, safranin O staining, and immunohistochemical staining were performed to determine the effects of IHP on the synthesis of extracellular matrix (ECM) proteins. Real-time polymerase chain reaction analysis was performed to measure the expression of genes related to chondrogenesis. The scratch and Live/Dead assays revealed that IHP significantly promoted the migration and proliferation of FPSCs and CPCs to different extents. The staining experiments showed greater production of cartilage ECM components (glycosaminoglycans and collagen II) by cells exposed to IHP, and the gene expression analysis demonstrated that IHP stimulated the expression of chondrocyte-related genes. Importantly, these effects of IHP were more prominent in CPCs than in FPSCs and CCs. Considering all of our experimental results combined, we conclude that CPCs demonstrated a stronger chondrogenic differentiation capacity than the FPSCs and CCs under stimulation with IHP. Thus, the use of CPCs, combined with mechanical stimulation, may represent a valuable strategy for cartilage tissue engineering. PMID:26771816

  13. 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. PMID:27129735

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Synergistic Effect of IGF-1 and OP-1 on Matrix Formation by Normal and OA Chondrocytes Cultured in Alginate Beads.

    PubMed Central

    Chubinskaya, Susan; Hakimiyan, Arnavaz; Pacione, Carol; Yanke, Adam; Rappoport, Lev; Aigner, Thomas; Rueger, David C.; Loeser, Richard F.

    2007-01-01

    Summary Objective Growth factor therapy may be useful for stimulation of cartilage matrix synthesis and repair. Thus, the purpose of our study was to further understand the effect of combined insulin-like growth factor 1 (IGF-1) and osteogenic protein 1 (OP-1) treatment on the matrix synthesized by human adult normal and osteoarthritic (OA) chondrocytes. Design Chondrocytes were isolated post-mortem from articular cartilage from tali of normal human donors and femoral condyles of OA patients undergoing knee replacement surgery. Cells were cultured in alginate beads for 21 days in four experimental groups: 1) “mini-ITS”-control; 2) 100ng/ml IGF-1; 3) 100ng/ml OP-1; 4) IGF-1 + OP-1, each at 100 ng/ml. Beads were processed for histological (Safranin O and fast green), morphometrical and immunohistochemical (aggrecan, decorin, type I, II, VI, and X collagens, and fibronectin accumulation) analyses. Results Histology showed that IGF-1 alone did not induce substantial matrix production. OP-1 alone caused a considerable matrix formation, but the highest matrix accumulation by normal and OA chondrocytes was found when OP-1 and IGF-1 were added together. Morphometrical analysis indicated larger matrices produced by OA chondrocytes than by normal cells under the combined treatment. All tested matrix proteins were more abundant in the combination group. Type X collagen was detected only under the combined OP-1 and IGF-1 treatment and was present at very low levels. Type I collagen was found only in OA chondrocytes. Conclusions The results obtained in the current study suggest that combined therapy with IGF-1 and OP-1 may have a greater potential in treating cartilage defects seen in OA than use of either growth factor alone. PMID:17126570

  20. Targeted removal of trichlorophenol in water by oleic acid-coated nanoscale palladium/zero-valent iron alginate beads.

    PubMed

    Chang, Jaewon; Woo, Heesoo; Ko, Myoung-Soo; Lee, Jaesang; Lee, Seockheon; Yun, Seong-Taek; Lee, Seunghak

    2015-08-15

    A new material was developed and evaluated for the targeted removal of trichlorophenol (TCP) from among potential interferents which are known to degrade removal activity. To achieve TCP-targeted activity, an alginate bead containing nanoscale palladium/zero-valent iron (Pd/nZVI) was coated with a highly hydrophobic oleic acid layer. The new material (Pd/nZVI-A-O) preferentially sorbed TCP from a mixture of chlorinated phenols into the oleic acid cover layer and subsequently dechlorinated it to phenol. The removal efficacy of TCP by Pd/nZVI-A-O was not affected by co-existing organic substances such as Suwannee River humic acid (SRHA), whereas the material without the oleic acid layer (Pd/nZVI-A) became less effective with increasing SRHA concentration. The inorganic substances nitrate and phosphate significantly reduced the reactivity of Pd/nZVI-A, however, Pd/nZVI-A-O showed similar TCP removal efficacies regardless of the initial inorganic ion concentrations. The influence of bicarbonate on the TCP removal efficacies of both Pd/nZVI-A and Pd/nZVI-A-O was not significant. The findings from this study suggest that Pd/nZVI-A-O, with its targeted, constant reactivity for TCP, would be effective for treating this contaminant in surface water or groundwater containing various competitive substrates. PMID:25819991

  1. 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

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

    PubMed Central

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

    2015-01-01

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

  3. The impact of functionalized CNT in the network of sodium alginate-based nanocomposite beads on the removal of Co(II) ions from aqueous solutions.

    PubMed

    Karkeh-Abadi, Fatemeh; Saber-Samandari, Samaneh; Saber-Samandari, Saeed

    2016-07-15

    Significant efforts have been made to develop highly efficient adsorbents to remove radioactive Co(II) ion pollutants from medical and industrial wastewaters. In this study, amide group functionalized multi-walled carbon nanotube (CNT-CONH2) imprinted in the network of sodium alginate containing hydroxyapatite, and new nanocomposite beads were synthesized. Then, they were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The prepared nanocomposite beads were used as an adsorbent of Co(II) ions from an aqueous solution. The presence and distribution of Co(II) ions in the surface of the nanocomposite beads was confirmed using FESEM, EDS and metal mapping analysis. The effect of various experimental conditions such as time, pH, and initial concentration of the adsorbate solution and temperature on the adsorption capacity of the nanocomposite beads were explored. The maximum Co(II) ions adsorption capacity of the prepared nanocomposite beads with the largest surface area of 163.4m(2)g(-1) was 347.8mgg(-1) in the optimized condition. The adsorption mechanism followed a pseudo-second-order kinetic model. Furthermore, the Freundlich appears to produce better fit than the Langmuir adsorption isotherm. Finally, thermodynamic studies suggest that endothermic adsorption process of Co(II) ions is spontaneous and thermodynamically favorable. PMID:27037477

  4. 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

  5. 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

  6. 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

  7. 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

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

    PubMed

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

    2015-08-01

    Monodisperse alginate microgels (10-50 μm) are created via droplet-based microfluidics by a novel crosslinking procedure. Ionic crosslinking of alginate is induced by release of chelated calcium ions. The process separates droplet formation and gelation reaction enabling excellent control over size and homogeneity under mild reaction conditions. Living mesenchymal stem cells are encapsulated and cultured in the generated 3D microenvironments. PMID:26039892

  9. In-vivo delivery of therapeutic proteins by genetically-modified cells: comparison of organoids and human serum albumin alginate-coated beads.

    PubMed

    Shinya, E; Dervillez, X; Edwards-Lévy, F; Duret, V; Brisson, E; Ylisastigui, L; Lévy, M C; Cohen, J H; Klatzmann, D

    1999-12-01

    We have designed a self-assembling multimeric soluble CD4 molecule by inserting the C-terminal fragment of the alpha chain of human C4-binding protein (C4bp alpha) at the C-terminal end of human soluble CD4 genes. This CD4-C4bp alpha fusion protein (sMulti-CD4) and two other reference molecules, a fusion protein of human serum albumin (HSA) and the first two domains of CD4 (HSA-CD4) and monomeric soluble CD4 (sMono-CD4), were delivered in vivo by genetically modified 293 cells. These cells were implanted in mice as organoids and also encapsulated in HSA alginate-coated beads. sMulti-CD4 showed an apparent molecular weight of about 300-350 kDa, in accordance with a possible heptamer formula. sMulti-CD4 produced either in cell culture or in vivo in mice appeared to be a better invitro inhibitor of HIV infection than sMono-CD4. Plasma levels of sMulti-CD4, HSA-CD4, and sMono-CD4 reached approximately 2,300, 2,700, and 170 ng/mL, respectively, 13 weeks after in-vivo organoid implantation, which had formed tumours at that time. This suggests that the plasma half-life of sMulti-CD4 is much longer than that of sMono-CD4. The 293 xenogeneic cells encapsulated in HSA alginate-coated beads remained alive and kept secreting sMono-CD4 or HSA-CD4 continuously at significant levels for 18 weeks in nude mice, without tumour formation. When implanted in immunocompetent Balb/c mice, they were rejected two to three weeks after implantation. In contrast, encapsulated BL4 hybridoma cells remained alive and kept secreting BL4 anti-CD4 mAb for at least four weeks in Balb/c mice. These results suggest the clinical potential of the C4bp-multimerizing system, which could improve both the biological activity and the poor in-vivo pharmacokinetic performance of a monomeric functional protein like soluble CD4. These data also show that a systemic delivery of therapeutic proteins, including immunoglobulins, can be obtained by the in-vivo implantation of engineered allogeneic cells encapsulated

  10. Chitosan silk-based three-dimensional scaffolds containing gentamicin-encapsulated calcium alginate beads for drug administration and blood compatibility.

    PubMed

    Mehta, Abijeet Singh; Singh, Brijesh K; Singh, Nandita; Archana, D; Snigdha, Kirti; Harniman, Robert; Rahatekar, Sameer S; Tewari, R P; Dutta, P K

    2015-04-01

    In the present study gentamicin was encapsulated within calcium alginate beads and incorporated into porous chitosan, gelatin, double-hybrid silk fibroin, chitosan/gelatin and double-hybrid silk fibroin/chitosan scaffolds. Physiochemical, morphological and biological properties of fabricated amenable model systems were evaluated, revealing hemocompatible nature of double-hybrid silk fibroin/chitosan and double-hybrid silk fibroin scaffolds of hemolysis %<5 and porosity >85%. Fourier transform infrared results confirmed the blend formation and scanning electron microscope images showed good interconnectivity. Double-hybrid silk fibroin/chitosan-blended scaffold shows higher compressive strength and compressive modulus than other fabricated scaffolds. A comparative drug release profile of fabricated scaffolds revealed that double-hybrid silk fibroin/chitosan scaffold is a pertinent model system because of its prolonged drug release, optimal hemocompatability and high compressive modulus. PMID:25492055

  11. 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. PMID:27010340

  12. Prilling for the development of multi-particulate colon drug delivery systems: pectin vs. pectin-alginate beads.

    PubMed

    Auriemma, Giulia; Mencherini, Teresa; Russo, Paola; Stigliani, Mariateresa; Aquino, Rita P; Del Gaudio, Pasquale

    2013-01-30

    This paper proposes a multi-particulate drug delivery system produced by prilling technique in combination with an enteric coating. Optimization of process parameters, such as feed viscosity at nozzle, selection of cross-linker, pH of the gelling solution and cross-linking time, allows to obtain beads with strong gelled matrix. Results showed that dextran/piroxicam beads demonstrated high encapsulation efficiency, very narrow dimensional distribution and high sphericity. Coated beads retained shape and narrow size distribution of the uncoated particles. Moreover, the strength of the produced Zn(2+)-pectinate beads allows to reduce Eudragit coating thickness. Piroxicam loaded multi-particulate systems show an interesting prolonged drug release in intestinal fluids. Hence, such platforms could be proposed for the treatment of inflammatory bowel diseases. PMID:23218307

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

    PubMed

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

    2016-01-01

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

  14. 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

    2015-01-01

    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

  15. 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

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

    PubMed

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

    2014-03-01

    Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200-400 μm) with narrow size distribution (± 5-7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15-25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate-cell interaction within these structures will be forthcoming. PMID:24433889

  17. 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. PMID:24136467

  18. 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

  19. 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

  20. Fabrication of novel oxygen-releasing alginate beads as an efficient oxygen carrier for the enhancement of aerobic bioremediation of 1,4-dioxane contaminated groundwater.

    PubMed

    Lee, Chung-Seop; Le Thanh, Thao; Kim, Eun-Ju; Gong, Jianyu; Chang, Yoon-Young; Chang, Yoon-Seok

    2014-11-01

    Oxygen-releasing alginate beads (ORABs), a new concept of oxygen-releasing compounds (ORCs) designed to overcome some limitations regarding the fast oxygen release rate and the high pH equilibrium of ORCs, were fabricated to promote the stimulation of aerobic biodegradation in anaerobic groundwater. Slow oxygen-releasing rate and maintenance of constant pH were achieved by changing the parameters (ionic radius and valence) related to the cross-linking ions composing ORABs, and the best results were obtained for ORABs cross-linked with Al (Al-ORABs). Furthermore, the mechanism of the improved aerobic biodegradation using Al-ORABs under oxygen-limiting groundwater conditions was elucidated in batch and column studies with 1,4-dioxane and Mycrobacterium sp. PH-06 as a model contaminant and aerobic microbes, respectively. Maximum 1,4-dioxane degradations of 99% and 68.1% were achieved when Al-ORABs were applied in batch and column conditions, respectively, whereas 34.3% and 18% of 1,4-dioxane were degraded without Al-ORABs in batch and column conditions, respectively. PMID:25189509

  1. 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

  2. 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. PMID:24676571

  3. 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

  4. Using a CD-like microfluidic platform for uniform calcium alginate drug carrier generation

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Kai; Huang, Keng-Shiang; Chang, Jia-Yaw; Wu, Chun-Han; Lin, Yu-Cheng

    2007-01-01

    In this paper the manipulation of monodisperse Ca-alginate microparticles using a polymer-based CD-like microfluidic platform and a reaction of external gelation is presented. Our strategy was based on associating the rapid injection molding process for cross-junction microchannel with the sheath focusing effect to form uniform water-in-oil (w/o) emulsions. These fine emulsions, consisting of 1.5% w/v Na-alginate, were then dripped into an oil solution containing 20% w/v calcium chloride (CaCl II) to accomplish Ca-alginate microspheres in an efficient manner. We have demonstrated that one can control the size of Ca-alginate microparticles from 20 µm to 50 µm in diameter (with a variation less than 10%) by altering the relative sheath/sample flow rate ratio. Experimental data showed that for a given fixed dispersed phase flow (sample flow), the emulsion size decreased as the average velocity of the continuous phase (oil flow) increased. The proposed CD-like microfluidic platform is capable of generating relatively uniform microdroplets and has the advantages of active control of droplet diameter, simple and low cost process, and high throughput.

  5. 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

  6. 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

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

    PubMed

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

    2014-12-14

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

  8. Increased pigment and lipid content, lipid variety, and cell and population size of the microalgae Chlorella spp. when co-immobilized in alginate beads with the microalgae-growth-promoting bacterium Azospirillum brasilense.

    PubMed

    de-Bashan, Luz E; Bashan, Yoav; Moreno, Manuel; Lebsky, Vladimir K; Bustillos, Jose J

    2002-06-01

    Three strains of the freshwater microalgae used for wastewater treatment, Chlorella vulgaris and Chlorella sorokiniana co-immobilized separately in alginate beads with the microalgae-growth-promoting bacterium Azospirillum brasilense Cd, resulted in significant changes in microalgal-population size, cell size, cell cytology, pigment, lipid content, and the variety of fatty acids produced in comparison with microalgae immobilized in alginate without the bacterium. Cells of C. vulgaris UTEX 2714 did not change in size, but the population size within the beads significantly increased. On the other hand, C. vulgaris UTEX 395 cells grew 62% larger, but their numbers did not increase. The population of C. sorokiniana UTEX 1602 increased, but not their cell size. The content of pigments chlorophyll a and b, lutein, and violoaxanthin increased in all microalgal species. The lipid content also significantly increased in all three strains, and the number of different fatty acids in the microalgae increased from four to eight. This study indicates that the microalgae-growth-promoting bacterium induced significant changes in the metabolism of the microalgae. PMID:12166678

  9. 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.

  10. 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. PMID:26322476

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

    NASA Astrophysics Data System (ADS)

    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 ( T2) 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 ( T1) and spin-spin ( T2) 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 T2 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.

  12. 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

  13. 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

  14. 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

  15. Silk sericin-alginate-chitosan microcapsules: hepatocytes encapsulation for enhanced cellular functions.

    PubMed

    Nayak, Sunita; Dey, Sanchareeka; Kundu, Subhas C

    2014-04-01

    The encapsulation based technology permits long-term delivery of desired therapeutic products in local regions of body without the need of immunosuppressant drugs. In this study microcapsules composed of sericin and alginate micro bead as inner core and with an outer chitosan shell are prepared. This work is proposed for live cell encapsulation for potential therapeutic applications. The sericin protein is obtained from cocoons of non-mulberry silkworm Antheraea mylitta. The sericin-alginate micro beads are prepared via ionotropic gelation under high applied voltage. The beads further coated with chitosan and crosslinked with genipin. The microcapsules developed are nearly spherical in shape with smooth surface morphology. Alamar blue assay and confocal microscopy indicate high cell viability and uniform encapsulated cell distribution within the sericin-alginate-chitosan microcapsules indicating that the microcapsules maintain favourable microenvironment for the cells. The functional analysis of encapsulated cells demonstrates that the glucose consumption, urea secretion rate and intracellular albumin content increased in the microcapsules. The study suggests that the developed sericin-alginate-chitosan microcapsule contributes towards the development of cell encapsulation model. It also offers to generate enriched population of metabolically and functionally active cells for the future therapeutics especially for hepatocytes transplantation in acute liver failure. PMID:24486492

  16. Microencapsulation of islets within alginate/poly(ethylene glycol) gels cross-linked via Staudinger ligation

    PubMed Central

    Hall, Kristina K.; Gattás-Asfura, Kerim M.; Stabler, Cherie L.

    2010-01-01

    Functionalized alginate and PEG polymers were used to generate covalently linked alginate-PEG (XAlgPEG) microbeads of high stability. The cell-compatible Staudinger ligation scheme was used to chemoselectively cross-link phosphine-terminated poly(ethylene glycol) (PEG) to azide-functionalized alginate, resulting in XAlgPEG hydrogels. XAlgPEG microbeads were formed by co-incubation of the two polymers, followed by ionic cross-linking of the alginate using barium ions. The enhanced stability and gel properties of the resulting XAlgPEG microbeads, as well as the compatibility of these polymers for the encapsulation of islets and beta cells lines, were investigated. Our data show that XAlgPEG microbeads exhibit superior resistance to osmotic swelling compared to traditional barium cross-linked alginate (Ba-Alg) beads, with a 5-fold reduction in observed swelling, as well as resistance to dissolution via chelation solution. Diffusion and porosity studies found XAlgPEG beads to exhibit properties comparable to standard Ba-Alg. Our data found XAlgPEG microbeads to be highly cell compatible with insulinoma cell lines, as well as rat and human pancreatic islets, where the viability and functional assessment of cells within XAlgPEG were comparable to Ba-Alg controls. The remarkable improved stability, as well as demonstrated cellular compatibility, of XAlgPEG hydrogels makes them an appealing option for a wide variety of tissue engineering applications. PMID:20654745

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

    PubMed Central

    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.

    2015-01-01

    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. PMID:26074490

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

    PubMed

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

    2007-01-01

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

  19. 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

  20. 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

  1. 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

  2. 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

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

    PubMed

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

    2011-01-31

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

  4. Gastroretentive delivery systems: hollow beads.

    PubMed

    Talukder, R; Fassihi, R

    2004-04-01

    The objective of this study was to develop a floatable multiparticulate system with potential for intragastric sustained drug delivery. Cross-linked beads were made by using calcium and low methoxylated pectin (LMP), which is an anionic polysaccharide, and calcium, LMP, and sodium alginate. Beads were dried separately in an air convection type oven at 40 degrees C for 6 hours and in a freeze dryer to evaluate the changes in bead characteristics due to process variability. Riboflavin (B-2), tetracycline (TCN), and Methotrexate (MTX) were used as model drugs for encapsulation. Ionic and nonionic excipients were added to study their effects on the release profiles of the beads. The presence of noncross linking agents in low amounts (less than 2%) did not significantly interfere with release kinetics. For an amphoteric drug like TCN, which has pH dependent solubility, three different pHs (1.5, 5.0, and 8.0) of cross-linking media were used to evaluate the effects of pH on the drug entrapment capacity of the beads. As anticipated, highest entrapment was possible when cross-linking media pH coincided with least drug solubility. Evaluation of the drying process demonstrated that the freeze-dried beads remained buoyant over 12 hours in United States Pharmacopeia (USP) hydrochloride buffer at pH 1.5, whereas the air-dried beads remained submerged throughout the release study. Confocal laser microscopy revealed the presence of air-filled hollow spaces inside the freeze dried beads, which was responsible for the flotation property of the beads. However, the release kinetics from freeze dried beads was independent of hydrodynamic conditions. Calcium-pectinate-alginate beads released their contents at much faster rates than did calcium-pectinate beads (100% in 10 hours vs. 50% in 10 hours). It appears that the nature of cross-linking, drying method, drug solubility, and production approach are all important and provide the opportunity and potential for development of a

  5. Extended release of vitamins from magnetite loaded polyanionic polymeric beads.

    PubMed

    Sonmez, Maria; Verisan, Cristina; Voicu, Georgeta; Ficai, Denisa; Ficai, Anton; Oprea, Alexandra Elena; Vlad, Mihaela; Andronescu, Ecaterina

    2016-08-30

    Here we explore a novel approach of increasing the release duration of folic and ascorbic acid from magnetite entrapped into calcium-alginate beads. Synthesis and characterization of magnetite-vitamins complexes are reported. The magnetite-vitamins complexes were characterized by FT-IR, XRD, SEM, BET and DTA-TG. Also calcium-alginate magnetic beads were prepared by dripping a mixture of sodium alginate with magnetite-vitamins complexes into calcium chloride solution. Extended release profile of the two experimental models was evaluated and quantified by UV-vis. PMID:26626225

  6. Gel bead composition for metal adsorption

    SciTech Connect

    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.

  7. 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.

  8. Microfluidic bead suspension hopper.

    PubMed

    Price, Alexander K; MacConnell, Andrew B; Paegel, Brian M

    2014-05-20

    Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidic handling and analysis. We developed a bead suspension hopper that exploits sedimentation to load beads into a microfluidic droplet generator. A suspension hopper continuously delivered synthesis resin beads (17 μm diameter, 112,000 over 2.67 h) functionalized with a photolabile linker and pepstatin A into picoliter-scale droplets of an HIV-1 protease activity assay to model ultraminiaturized compound screening. Likewise, trypsinogen template DNA-coated magnetic beads (2.8 μm diameter, 176,000 over 5.5 h) were loaded into droplets of an in vitro transcription/translation system to model a protein evolution experiment. The suspension hopper should effectively remove any barriers to using suspensions as sample inputs, paving the way for microfluidic automation to replace robotic library distribution. PMID:24761972

  9. Gene-scrambling mutagenesis: generation and analysis of insertional mutations in the alginate regulatory region of Pseudomonas aeruginosa.

    PubMed

    Mohr, C D; Deretic, V

    1990-11-01

    A novel method for random mutagenesis of targeted chromosomal regions in Pseudomona aeruginosa was developed. This method can be used with a cloned DNA fragment of indefinite size that contains a putative gene of interest. Cloned DNA is digested to produce small fragments that are then randomly reassembled into long DNA inserts by using cosmid vectors and lambda packaging reaction. This DNA is then transferred into P. aeruginosa and forced into the chromosome via homologous recombination, producing in a single step a random set of insertional mutants along a desired region of the chromosome. Application of this method to extend the analysis of the alginate regulatory region, using a cloned 6.2-kb fragment with the algR gene and the previously uncharacterized flanking regions, produced several insertional mutations. One mutation was obtained in algR, a known transcriptional regulatory of mucoidy in P. aeruginosa. The null mutation of algR was generated in a mucoid derivative of the standard genetic strain PAO responsive to different environmental factors. This mutation was used to demonstrate that the algR gene product was not essential for the regulation of its promoters. Additional insertions were obtained in regions downstream and upstream of algR. A mutation that did not affect mucoidy was generated in a gene located 1 kb upstream of algR. This gene was transcribed in the direction opposite that of algR transcription and encoded a polypeptide of 47 kDa. Partial nucleotide sequence analysis revealed strong homology of its predicted gene product with the human and yeast argininosuccinate lyases. An insertion downstream of algR produced a strain showing reduced induction of mucoidy in response to growth on nitrate as the nitrogen source. PMID:2121708

  10. Gene-scrambling mutagenesis: generation and analysis of insertional mutations in the alginate regulatory region of Pseudomonas aeruginosa.

    PubMed Central

    Mohr, C D; Deretic, V

    1990-01-01

    A novel method for random mutagenesis of targeted chromosomal regions in Pseudomona aeruginosa was developed. This method can be used with a cloned DNA fragment of indefinite size that contains a putative gene of interest. Cloned DNA is digested to produce small fragments that are then randomly reassembled into long DNA inserts by using cosmid vectors and lambda packaging reaction. This DNA is then transferred into P. aeruginosa and forced into the chromosome via homologous recombination, producing in a single step a random set of insertional mutants along a desired region of the chromosome. Application of this method to extend the analysis of the alginate regulatory region, using a cloned 6.2-kb fragment with the algR gene and the previously uncharacterized flanking regions, produced several insertional mutations. One mutation was obtained in algR, a known transcriptional regulatory of mucoidy in P. aeruginosa. The null mutation of algR was generated in a mucoid derivative of the standard genetic strain PAO responsive to different environmental factors. This mutation was used to demonstrate that the algR gene product was not essential for the regulation of its promoters. Additional insertions were obtained in regions downstream and upstream of algR. A mutation that did not affect mucoidy was generated in a gene located 1 kb upstream of algR. This gene was transcribed in the direction opposite that of algR transcription and encoded a polypeptide of 47 kDa. Partial nucleotide sequence analysis revealed strong homology of its predicted gene product with the human and yeast argininosuccinate lyases. An insertion downstream of algR produced a strain showing reduced induction of mucoidy in response to growth on nitrate as the nitrogen source. Images PMID:2121708

  11. Magneto-responsive alginate capsules

    NASA Astrophysics Data System (ADS)

    Degen, Patrick; Zwar, Elena; Schulz, Imke; Rehage, Heinz

    2015-05-01

    Upon incorporation of magnetic nanoparticles (mNPs) into gels, composite materials called ferrogels are obtained. These magneto-responsive systems have a wide range of potential applications including switches and sensors as well as drug delivery systems. In this article, we focus on the properties of calcium alginate capsules, which are widely used as carrier systems in medicine and technology. We studied the incorporation of different kinds of mNPs in matrix capsules and in the core and the shell of hollow particles. We found out that not all particle-alginate or particle-CaCl2 solution combinations were suitable for a successful capsule preparation on grounds of a destabilization of the nanoparticles or the polymer. For those systems allowing the preparation of switchable beads or capsules, we systematically studied the size and microscopic structure of the capsules, their magnetic behavior and mechanical resistance.

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

    PubMed

    Khotimchenko, Maxim; Kovalev, Valeri; Khotimchenko, Yuri

    2008-01-01

    The absorption of Pb(II) ions from aqueous solution by different alginate compounds was studied in a batch sorption system. Water soluble sodium alginate and insoluble calcium alginate beads were investigated. The lead-binding capacity of both alginate compounds was highest within the pH range 6-8. The binding capacities and rates of Pb(II) ions by alginate compounds were evaluated. The Langmuir, Freundlich, and Bruneaur, Emmet and Teller (BET) sorption models were applied to describe the isotherms and isotherm constants. Sorption isothermal data could be well interpreted by the Langmuir model. The results obtained through the study suggest that alginate compounds are favorable sorbents. The largest amount of Pb(II) ions were bound by sodium alginate although the difference between two compounds was slight. Therefore, alginate substances may be considered as an alternative for sorption and removal of Pb(II) ions from wastewaters. PMID:18814578

  13. 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. PMID:26560232

  14. 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

  15. Artemisia arborescens L essential oil loaded beads: preparation and characterization.

    PubMed

    Lai, Francesco; Loy, Giuseppe; Manconi, Maria; Manca, Maria Letizia; Fadda, Anna Maria

    2007-01-01

    The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a slight decrease in the loading efficiency. The surface morphology of the different bead formulations were studied using scanning electron microscopy (SEM). Stability studies over a 3-month period showed that glutaraldehyde reacted with some components of Artemisia arborescens L essential oil, changing its composition. Calcium alginate beads showed an in vitro controlled release of the essential oil for the investigated 24 hours, while the use of glutaraldehyde as a cross-linking agent was found not appropriate because of the interactions with azulene derivatives and the low degree of matrix cross-linkage. PMID:17915817

  16. 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.

  17. 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*).

  18. 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).

  19. Biosorbent encapsulation in calcium alginate: Effects of process variables on Cr(VI) removal from solutions.

    PubMed

    Šillerová, Hana; Komárek, Michael; Liu, Chang; Poch, Jordi; Villaescusa, Isabel

    2015-09-01

    Selected biosorbents, brewers draff and grape waste, have been encapsulated in calcium alginate beads and used for the removal of Cr(VI) from aqueous solutions. The effects of encapsulation variables, including the type of waste, the percentage of waste in the beads and the curing time of the beads in CaCl2, on the diameters of the beads and Cr(VI) sorption kinetics have been evaluated. In total, 21 different types of beads were produced. The diameters of the beads increased with increasing amounts of encapsulated biomaterial. Beads that contained grape waste were larger than those containing brewers draff. The most efficient beads for Cr(VI) removal were beads that contained 4% (w/w) of grape waste. No significant differences in the kinetics of Cr(VI) sorption were found with respect to the curing time variable in the case of grape waste calcium alginate beads. Statistical analysis confirmed that the type and percentage of waste are the critical parameters influencing the diameters of the beads and Cr(VI) removal. It was proven that the sorption efficiencies of the beads containing draff and grape waste encapsulated under the optimum conditions were much higher than the efficiencies obtained when using both wastes in their native states. PMID:26102330

  20. Chromatic biosensor for detection of phosphinothricin acetyltransferase by use of polydiacetylene vesicles encapsulated within automatically generated immunohydrogel beads.

    PubMed

    Jung, Sung-Ho; Jang, Huisoo; Lim, Min-Cheol; Kim, Jae-Hwan; Shin, Kong-Sik; Kim, Sun Min; Kim, Hae-Yeong; Kim, Young-Rok; Jeon, Tae-Joon

    2015-02-17

    We developed a simple and sensitive colorimetric biosensor in the form of microparticles by using polydiacetylene (PDA) vesicles encapsulated within a hydrogel matrix for the detection of phosphinothricin acetyltransferase (PAT) protein, which is one of the most important marker proteins in genetically modified (GM) crops. Although PDA is commonly used as a sensing material due to its unique colorimetric properties, existing PDA biosensors are ineffective due to their low sensitivity as well as their lack of robustness. To overcome these disadvantages, we devised immunohydrogel beads made of anti-PAT-conjugated PDA vesicles embedded at high density within a poly(ethylene glycol) diacrylate (PEG-DA) hydrogel matrix. In addition, the construction of immunohydrogel beads was automated by use of a microfluidic device. In the immunoreaction, the sensitivity of antibody-conjugated PDA vesicles was significantly amplified, as monitored by the unaided eye. The limit of detection for target molecules reached as low as 20 nM, which is sufficiently low enough to detect target materials in GM organisms. Collectively, the results show that immunohydrogel beads constitute a promising colorimetric sensing platform for onsite testing in a number of fields, such as the food and medical industries, as well as warfare situations. PMID:25615891

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

    PubMed

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

    1996-02-01

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

  2. Alginate Hydrogel: A Shapeable and Versatile Platform for in Situ Preparation of Metal-Organic Framework-Polymer Composites.

    PubMed

    Zhu, He; Zhang, Qi; Zhu, Shiping

    2016-07-13

    This work reports a novel in situ growth approach for incorporating metal-organic framework (MOF) materials into an alginate substrate, which overcomes the challenges of processing MOF particles into specially shaped structures for real industrial applications. The MOF-alginate composites are prepared through the post-treatment of a metal ion cross-linked alginate hydrogel with a MOF ligand solution. MOF particles are well distributed and embedded in and on the surface of the composites. The macroscopic shape of the composite can be designed by controlling the shape of the corresponding hydrogel; thus MOF-alginate beads, fibers, and membranes are obtained. In addition, four different MOF-alginate composites, including HKUST-1-, ZIF-8-, MIL-100(Fe)-, and ZIF-67-alginate, were successfully prepared using different metal ion cross-linked alginate hydrogels. The mechanism of formation is revealed, and the composite is demonstrated to be an effective absorbent for water purification. PMID:27315047

  3. 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

  4. 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

  5. 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

  6. Chitosan/apatite composite beads prepared by in situ generation of apatite or Si-apatite nanocrystals.

    PubMed

    Davidenko, Natalia; Carrodeguas, Raúl G; Peniche, Carlos; Solís, Yaimara; Cameron, Ruth E

    2010-02-01

    The objective of this work was to develop nanocrystalline apatite (Ap) dispersed in a chitosan (CHI) matrix as a material for applications in bone tissue engineering. CHI/Ap composites of different weight ratios (20/80, 50/50 and 80/20) and with CHI of different molecular weights were prepared by a biomimetic stepwise route. Firstly, CaHPO(4).2H(2)O (DCPD) crystals were precipitated from Ca(CH(3)COO)(2) and NaHPO(4) in the bulk CHI solution, followed by the formation of CHI/DCPD beads by coacervation. The beads were treated with Na(3)PO(4)/Na(5)P(3)O(10) solution (pH 12-13) to crosslink the CHI and to hydrolyse the DCPD to nanocrystalline Ap. This new experimental procedure ensured that complete conversion of DCPD into sodium-substituted apatite was achieved without appreciable increases in its crystallinity and particle size. In addition, composites with silicon-doped Ap were prepared by substituting Na(3)PO(4) by Na(2)SiO(3) in the crosslinking/hydrolysis step. Characterization of the resultant composites by scanning electron microscopy, X-ray powder diffraction (XRD), thermal analysis and Fourier transform infrared spectroscopy confirmed the formation, within the CHI matrix, of nanoparticles of sodium- and carbonate-substituted hydroxyapatite [Ca(10-x)Na(x)(PO(4))(6-x)(CO(3))(x)(OH)(2)] with diameters less than 20nm. Relatively good correspondence was shown between the experimentally determined inorganic content and that expected theoretically. Structural data obtained from its XRD patterns revealed a decrease in both crystal domain size and cell parameters of Ap formed in situ with increasing CHI content. It was found that the molecular weight of CHI and silicate doping both affected the nucleation and growth of apatite nanocrystallites. These effects are discussed in detail. PMID:19632363

  7. 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

  8. Gold bead implants.

    PubMed

    Durkes, T E

    1992-03-01

    Gold bead implantation is an experimental area of study in the acupuncture field dealing with chronic diseases. Special acupuncture techniques are required to implant the gold beads successfully in the proper location. Gold beads are used to treat degenerative joint disease, osteochondritis, osteochondritis dessicans, ventral spondylosis, and seizures. PMID:1581658

  9. Photonic hydrogel beads for controlled release of risedronate

    NASA Astrophysics Data System (ADS)

    Khajuria, Deepak K.; Roy Mahapatra, D.

    2014-03-01

    pH-sensitive photonic composite hydrogel beads composed of sodium alginate and risedronate sodium (SA/RIS) was prepared crosslinked by Ca2+ owing to the ionic gelation of SA. The structure and surface morphology of the composite hydrogel beads were characterized by SEM. pH-sensitivity of these composite hydrogels beads and the release behaviors of drug from them were investigated. The results showed that the composite hydrogel beads had good pH-sensitivity. The drug loading and encapsulation efficiency were 27.7% and 92% for RIS, respectively. The cumulative release ratios of RIS from the composite hydrogel beads were 2.47% in pH 2.1 solution and 83 % in pH 6.8 solutions within 24 h, respectively. However, the cumulative release ratio of RIS in pH 7.4 solution reached 91% within 7 h. It is proposed that the novel photonic SA/RIS composite hydrogel bead could possess the potential of an increased intestinal absorption and fewer adverse effects of RIS. The pH and salt response of photonic hydrogel bead, as well as the encapsulation of macromolecules, are promising for applications in biomedicine and biotechnology.

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

    PubMed

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

    2013-04-01

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

  11. 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.

  12. 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.

  13. Evaluation of microbeads of calcium alginate as a fluidized bed medium for affinity chromatography of Aspergillus niger Pectinase.

    PubMed

    Roy, Ipsita; Jain, Sulakshana; Teotia, Sunita; Gupta, Munishwar Nath

    2004-01-01

    Calcium alginate microbeads (212-425 microm) were prepared by spraying 2% (w/v) alginate solution into 1 M CaCl2 solution. The fluidization behavior of these beads was studied, and the bed expansion index and terminal velocity were found to be 4.3 and 1808 cm h(-1), respectively. Residence time distribution curves showed that the dispersion of the protein was much less with these microbeads than with conventionally prepared calcium alginate macrobeads when both kinds of beads were used for chromatography in a fluidized bed format. The fluidized bed of these beads was used for the purification of pectinase from a commercial preparation. The media performed well even with diluted feedstock; 90% activity recovery with 211-fold purification was observed. PMID:15458334

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

    PubMed

    Yu, L; Grist, S M; Nasseri, S S; Cheng, E; Hwang, Y-C E; Ni, C; Cheung, K C

    2015-03-01

    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

  15. 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

  16. 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

  17. 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

  18. 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...

  19. 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...

  20. 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...

  1. 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...

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

    PubMed

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

    2012-06-01

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

  3. 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

  4. Fused Bead Analysis of Diogenite Meteorites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D.W.; Beck, B.W.; McSween, H.Y.; Lee, C.T. A.

    2009-01-01

    Bulk rock chemistry is an essential dataset in meteoritics and planetary science [1]. A common method used to obtain the bulk chemistry of meteorites is ICP-MS. While the accuracy, precision and low detection limits of this process are advantageous [2], the sample size used for analysis (approx.70 mg) can be a problem in a field where small and finite samples are the norm. Fused bead analysis is another bulk rock analytical technique that has been used in meteoritics [3]. This technique involves forming a glass bead from 10 mg of sample and measuring its chemistry using a defocused beam on a microprobe. Though the ICP-MS has lower detection limits than the microprobe, the fused bead method destroys a much smaller sample of the meteorite. Fused bead analysis was initially designed for samples with near-eutectic compositions and low viscosities. Melts generated of this type homogenize at relatively low temperatures and produce primary melts near the sample s bulk composition [3]. The application of fused bead analysis to samples with noneutectic melt compositions has not been validated. The purpose of this study is to test if fused bead analysis can accurately determine the bulk rock chemistry of non-eutectic melt composition meteorites. To determine this, we conduct two examinations of the fused bead. First, we compare ICP-MS and fused bead results of the same samples using statistical analysis. Secondly, we inspect the beads for the presence of crystals and chemical heterogeneity. The presence of either of these would indicate incomplete melting and quenching of the bead.

  5. Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1

    PubMed Central

    Derikvand, Peyman; Etemadifar, Zahra

    2014-01-01

    Background: Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. Objectives: The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Materials and Methods: Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. Results: The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. Conclusions: The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels. PMID:25147685

  6. 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.

  7. 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

  8. 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.

  9. Development and Evaluation of Dual Cross-Linked Pulsatile Beads for Chronotherapy of Rheumatoid Arthritis

    PubMed Central

    Bansal, Abanesh kumar; Pande, Vishal

    2013-01-01

    In the present investigation, pulsatile release beads were prepared by ionic gelation technique. Lornoxicam dual cross-linked beads were prepared by dropping dispersed phase of lornoxicam, pectin, and sodium alginate into the dispersion phase of different concentrations of calcium chloride solution followed by aluminium chloride solution. The formulated beads were further coated by Eudragit L & S 100 in the ratio 1 : 2 w/w in order to achieve desired lag time. In vitro release study showed lag time of 5–8 h before release of lornoxicam from the formulated beads. Thus, formulated dual cross-linked beads when administered at bed time may release lornoxicam when needed most for chronotherapeutics of early morning rheumatoid arthritis attacks in chronic patients. PMID:26556001

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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. PMID:26593570

  15. Noncovalent hydrogel beads as microcarriers for cell culture.

    PubMed

    Wieduwild, Robert; Krishnan, Swati; Chwalek, Karolina; Boden, Annett; Nowak, Mirko; Drechsel, David; Werner, Carsten; Zhang, Yixin

    2015-03-23

    Hydrogel beads as microcarriers could have many applications in biotechnology. However, bead formation by noncovalent cross-linking to achieve high cell compatibility by avoiding chemical reactions remains challenging because of rapid gelation rates and/or low stability. Here we report the preparation of homogeneous, tunable, and robust hydrogel beads from peptide-polyethylene glycol conjugates and oligosaccharides under mild, cell-compatible conditions using a noncovalent crosslinking mechanism. Large proteins can be released from beads easily. Further noncovalent modification allows for bead labeling and functionalization with various compounds. High survival rates of embedded cells were achieved under standard cell culture conditions and after freezing the beads, demonstrating its suitability for encapsulating and conserving cells. Hydrogel beads as functional system have been realized by generating protein-producing microcarriers with embedded eGFP-secreting insect cells. PMID:25650774

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. Processing and Characterization of MMC Beads Based on Zirconia and TRIP Steel

    NASA Astrophysics Data System (ADS)

    Oppelt, Marie; Wenzel, Claudia; Aneziris, Christos G.; Berek, Harry

    2014-12-01

    A novel process for metal-matrix composite fabrication with the special focus on single beads and sintered bead structures is explored. The used gel-casting process by sodium alginate gelation is introduced, and various analyses with significant results are presented. The suspensions contained 16-7-3 steel and zirconia particles as well as sodium alginate and were subsequently added dropwise into water which contained solidifying agent for forming rubbery, substantially round beads. Sintered beads with adequate strength (~400 MPa) and perfect surface, homogeneous microstructure, and high energy absorption capability have been produced by this casting process. At lower strains (up to 15 pct), all zirconia reinforced steel beads obtain higher specific energy absorption (SEA) in comparison to pure steel beads. Especially the composition of 90 vol pct TRIP steel and 10 vol pct zirconia shows a significant improved energy absorption capability with 27.7 MJ/m3 at a strain of 15 pct. Pure steel only exhibits a SEA of 13.1 MJ/m3.

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

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

    PubMed

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

    2015-09-01

    A novel environmentally friendly biocomposite namely calcium alginate immobilized Ammi Visnaga (Khella) extraction waste was prepared by electrostatic extrusion method. A full factorial design 2(3) was used to optimize the beads preparation conditions. The effect of sodium alginate concentration (X1), biomass concentration (X2) and cross-linker concentration (X3) on the Cd(2+) removal efficiency was examined in a batch system with a fixed biocomposite dose of 1g/L. Using the experimental results, a linear mathematical model representing the influence of different variables and their interactions was obtained. The optimized values of X1, X2 and X3 were found to be 4.35%, 2.5% and 1.99% respectively. The biocomposite beads were characterized by ATR spectroscopy, scanning electron microscopy for the surface morphology and optical microscopic for the particles size measurements. PMID:26188304

  17. A large-area hemispherical perforated bead microarray for monitoring bead based aptamer and target protein interaction

    PubMed Central

    Choi, Jong Seob; Bae, Sunwoong; Kim, Kyung Hoon; Seo, Tae Seok

    2014-01-01

    Herein, we present a large-area 3D hemispherical perforated microwell structure for a bead based bioassay. Such a unique microstructure enables us to perform the rapid and stable localization of the beads at the single bead level and the facile manipulation of the bead capture and retrieval with high speed and efficiency. The fabrication process mainly consisted of three steps: the convex micropatterned nickel (Ni) mold production from the concave micropatterned silicon (Si) wafer, hot embossing on the polymer matrix to generate the concave micropattened acrylate sheet, and reactive ion etching to make the bottom holes. The large-area hemispherical perforated micropatterned acrylate sheet was sandwiched between two polydimethylsiloxane (PDMS) microchannel layers. The bead solution was injected and recovered in the top PDMS microchannel, while the bottom PDMS microchannel was connected with control lines to exert the hydrodynamic force in order to alter the flow direction of the bead solution for the bead capture and release operation. The streptavidin-coated microbead capture was achieved with almost 100% yield within 1 min, and all the beads were retrieved in 10 s. Lysozyme or thrombin binding aptamer labelled microbeads were trapped on the proposed bead microarray, and the in situ fluorescence signal of the bead array was monitored after aptamer-target protein interaction. The protein-aptamer conjugated microbeads were recovered, and the aptamer was isolated for matrix assisted laser desorption/ionization time-of-flight mass spectrometry analysis to confirm the identity of the aptamer. PMID:25587373

  18. 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

  19. Weld-Bead Shaver

    NASA Technical Reports Server (NTRS)

    Guirguis, Kamal; Price, Daniel S.

    1990-01-01

    Hand-held power tool shaves excess metal from inside circumference of welded duct. Removes excess metal deposited by penetration of tungsten/inert-gas weld or by spatter from electron-beam weld. Produces smooth transition across joint. Easier to use and not prone to overshaving. Also cuts faster, removing 35 in. (89 cm) of weld bead per hour.

  20. 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)

  1. 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).

  2. 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

  3. Structural Characterization of Sodium Alginate and Calcium Alginate.

    PubMed

    Hecht, Hadas; Srebnik, Simcha

    2016-06-13

    Alginate readily aggregates and forms a physical gel in the presence of cations. The association of the chains, and ultimately gel structure and mechanics, depends not only on ion type, but also on the sequence and composition of the alginate chain that ultimately determines its stiffness. Chain flexibility is generally believed to decrease with guluronic residue content, but it is also known that both polymannuronate and polyguluronate blocks are stiffer than heteropolymeric blocks. In this work, we use atomistic molecular dynamics simulation to primarily explore the association and aggregate structure of different alginate chains under various Ca(2+) concentrations and for different alginate chain composition. We show that Ca(2+) ions in general facilitate chain aggregation and gelation. However, aggregation is predominantly affected by alginate monomer composition, which is found to correlate with chain stiffness under certain solution conditions. In general, greater fractions of mannuronic monomers are found to increase chain flexibility of heteropolymer chains. Furthermore, differences in chain guluronic acid content are shown to lead to different interchain association mechanisms, such as lateral association, zipper mechanism, and entanglement, where the mannuronic residues are shown to operate as an elasticity moderator and therefore promote chain association. PMID:27177209

  4. 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

  5. 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.

  6. 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

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  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 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,...

  14. 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...

  15. 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,...

  16. 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,...

  17. 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,...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. 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

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

    NASA Astrophysics Data System (ADS)

    Kuo, Catherine Kyleen

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

  6. Exploitation of novel gum Prunus cerasoides as mucoadhesive beads for a controlled-release drug delivery.

    PubMed

    Seelan, T Veenus; Kumari, Henry Linda Jeeva; Kishore, Narra; Selvamani, Palanisamy; Lalhlenmawia, H; Thanzami, K; Pachuau, Lalduhsanga; Ruckmani, Kandasamy

    2016-04-01

    The present study deals with the formulation of pH-sensitive mucoadhesive beads using natural gum isolated from Prunus cerasoides (PC) in combination with sodium alginate (SA) for the controlled release of diclofenac sodium (DS). PC and SA composite (PC-SA), DS loaded SA (DS-SA) and DS loaded PC-SA (DS-PC-SA) beads were prepared by ionotropic gelation method. The absence of interaction between DS and PC-SA was shown by FTIR, DSC and TGA analyses. The optimized DS-PC-SA formulation exhibited mucoadhesive property and the controlled release of DS was achieved 68% in 12h. The in vitro release kinetics follows zero order with anomalous diffusion mechanism. Therefore, the formulated mucoadhesive beads with the novel gum are preferable for the controlled release of DS by prolonging the residence time of the drug in the gastrointestinal tract, overcoming the problems associated with the immediate release dosage forms of DS. PMID:26772921

  7. Chemoselective cross-linking and functionalization of alginate via Staudinger ligation

    PubMed Central

    Gattás-Asfura, Kerim M.; Stabler, Cherie L.

    2010-01-01

    In this study, we demonstrate the applicability of functionalized alginate to serve as a platform for the covalent cross-linking or immobilization of complimentary phosphine functionalized groups via the chemoselective Staudinger ligation scheme. Azide groups were covalently linked to alginate through a heterobifunctional polyethylene glycol (PEG) linker and carbodiimide. Degree of azide functionalization was varied as a function of carbodiimide concentration and determined by proton nuclear magnetic resonance (1H NMR) and infrared spectroscopy. Spontaneous and covalently cross-linked alginate-PEG gels were generated via the Staudinger ligation scheme upon incubation of the azide functionalized alginate with PEG chains having 1-methyl-2-diphenylphosphino-terephthalate (MDT) as end groups. Modulation of the MDT to N3 ratio resulted in variability of gel characteristics. In addition, azide functionalized alginate retained its capacity to instantaneously form hydrogels via electrostatic interaction with multivalent cations such as Ca2+ and Ba2+. Subsequently, covalent linkage of phosphine functionalized agents post-gelation of the alginate was feasible, as illustrated via linkage of MDT-PEG-carboxyfluorescein. Capitalization of the chemoselective and cell compatible Staudinger ligation scheme for covalent cross-linking of alginate hydrogels may enhance the utility of this polymer for the stable encapsulation of various cell types, in addition to their use in the immobilization of labeling agents, proteins, and other bioactive molecules. PMID:19848408

  8. Degradation of dimethylphthalate by cells of Bacillus sp. immobilized in calcium alginate and polyurethane foam.

    PubMed

    Niazi, J H; Karegoudar, T B

    2001-01-01

    A Bacillus sp. which is capable of degrading dimethylphthalate (DMP) was immobilized in calcium alginate and polyurethane foam for efficient and long term degradation of DMP. Freely suspended cells (10(12) cfu ml-1) degraded a maximum of 20 mM DMP. Whereas, alginate-(10(12)cfu g-1 beads) and polyurethane foam-entrapped (0.34 x 10(6-9) cfu g-1 foam cubes) cells degraded a maximum of 40 mM DMP within 12-15 days of incubation. Polyurethane foam-entrapped cells degraded 30 mM of DMP at 4 days and alginate-entrapped cells degraded within 10 to 12 days of incubation irrespective of the cell population. When the initial concentration of DMP increased to 50 mM, the DMP degrading ability of the immobilized cells was not increased even after 20 days. Repeated batch cultures by alginate-entrapped cells with initial 35 mM DMP loading could be reused for a maximum of 20 cycles. However, the degradation rate was gradually decreased when the beads were reused for more than 15 cycles. On the other hand, the foam-entrapped cells, with the same initial DMP loading there was no decrease in DMP degrading ability and could be reused for more than 20 cycles. The packed bed reactor with alginate-entrapped cells (1 x 10(10-12) cfu g-1 bead) could be continuously operated for 7-8 days with an initial 25 mM DMP at a flow rate of 50 ml h-1. Whereas, the polyurethane foam-entrapped cells (1 x 10(6-9) cfu g-1 foam cubes) could be operated continuously for more than 90 days with the same initial DMP loading at a flow rate of 100 ml h-1. Thus the enhanced degradation of DMP could be achieved by immobilizing the cells of Bacillus sp. in calcium alginate and polyurethane foam as compared to that of freely suspended cells. PMID:11501311

  9. Characterization of gliclazide release from Isabgol husk hydrogel beads by validated HPLC method.

    PubMed

    Sharma, Vipin K; Mazumdar, B

    2014-01-01

    Isabgol husk, a medicinally important natural polysaccharide was applied for fabrication of hydrogel beads by ionic gelation method to incorporate gliclazide. Different strengths of Isabgol husk and sodium alginate were utilized for assessing the process variables on formulation performance. Aqueous solution of calcium chloride in 2, 5 and 8% w/v strength was used as cross-linker for polymeric blends of Isabgol husk and sodium alginate. The formulations were characterized for various parameters such as particle size, swelling index, entrapment efficiency, in vitro release, and release kinetics. The quantification of gliclazide throughout the study was performed by HPLC method which was validated according to ICH guidelines for system suitability, linearity, accuracy, sensitivity, precession, robustness, and ruggedness. The surface morphology of beads was observed by scanning electron microscopy. The formed beads were brown, free flowing, spherical, and irregular in structure. The size in different formulations varied from 752.83 +/- 0.630 to 838.62 +/- 0.741 microm. The beads remained for 2-3 h in alkaline phosphate buffer (pH 7.4), after that they showed disintegration. The formulations released up to 95% of loaded gliclazide in phosphate buffer (pH 7.4) within 8 h. No significant difference was observed in parameters studied such as particle size, entrapment efficiency and swelling index for hydrogel beads during accelerated stability study (p > 0.05). The regression equation developed by HPLC method was linear (r5 > 0.9990) over the range 2.5 to 10 microg/mL. The limit of detection (LOD) and limit of quantification (LOQ) were 0.037619 microg/mL and 0.113997 microg/mL, respectively. The observed values for number of theoretical plates (N > or = 2000), tailing factor (T < or = 2), asymmetry factor (AF < or = 1), and relative standard deviation (RSD < or = 1%) of applied method showed the reliability for gliclazide estimation in Isabgol husk hydrogel beads. PMID

  10. 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.

  11. 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

  12. Encapsulation of porcine pancreatic islets within an immunoprotective capsule comprising methacrylated glycol chitosan and alginate.

    PubMed

    Hillberg, Anna Louise; Oudshoorn, Matthew; Lam, Janice B B; Kathirgamanathan, Kalyani

    2015-04-01

    Encapsulation of cells in biocompatible polymer matrices represents a powerful tool for cell-based therapies and therapeutic delivery systems. This technology has successfully been used to deliver pancreatic islets to humans for the treatment of Type 1 diabetes. However, the clinical impact of this technology may be improved by reducing the inflammatory response brought on after implantation of capsules in vivo. Within this study a biocompatible polymeric delivery system combining alginate and photo-crosslinked methacrylated glycol chitosan (MGC) was developed. This approach involved encapsulating cells in calcium-alginate beads, coating with MGC and photo-polymerizing using UVA in the presence of photo-initiator (VA-086), resulting in the formation of capsules ∼600 µm in size. Crosslinking of the MGC outer wall allowed control over capsule swelling and improved the capsules overall properties. Capsule characterization demonstrated the stabilizing influence of polymerization and fluorescence imaging showed that the distribution of glycol chitosan is dependent on molecular weight. Good islet viability and insulin release was demonstrated in vitro over the course of a month, and in vivo transplantation of the capsules demonstrated good biocompatibility, particularly when compared with standard alginate/poly-l-ornithine/alginate capsules. PMID:24915784

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

    PubMed

    Kregiel, Dorota; Berlowska, Joanna; Ambroziak, Wojciech

    2013-09-10

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

  14. Imaging Contrast Effects in Alginate Microbeads

    NASA Astrophysics Data System (ADS)

    Shapley, Nina; Hester-Reilly, Holly

    2007-03-01

    We have investigated the use of alginate gel microbeads as contrast agents for the study of suspension flows in complex geometries using nuclear magnetic resonance (NMR) imaging. These deformable particles can provide imaging contrast to rigid polymer particles in a bimodal suspension (two particle sizes). Microbeads were formed of crosslinked alginate gel, with or without trapped oil droplets. Crosslinking of the aqueous sodium alginate solution or the continuous phase of an oil-in-water emulsion occurred rapidly at gentle processing conditions. The alginate microbeads exhibit both spin-spin relaxation time (T2) contrast and diffusion contrast relative to both the suspending fluid and rigid polystyrene particles. Large alginate emulsion microbeads flowing in the abrupt, axisymmetric expansion geometry can be clearly distinguished from the suspending fluid and from rigid polymer particles in both spin-echo and diffusion weighted imaging. The alginate microbeads, particularly those containing trapped emulsion droplets, offer potential as a positive contrast agent in multiple NMR imaging applications.

  15. [Alginates in therapy for gastroesophageal reflux disease].

    PubMed

    Avdeev, V G

    2015-01-01

    This article presents evidence of the prevalence of gastroesophageal reflux disease (GERD) and highlights its main treatment options. Among its medications, particular emphasis is laid on alginates and their main mechanisms of action are described. There is information on the efficacy of alginates, including the alginate-antacid Gaviscon Double Action, in treating GERD. Recommendations for how to administer these drugs are given. PMID:26155630

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

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

    PubMed

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

    2016-02-01

    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

  4. 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

  5. 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

  6. 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

  7. Microfluidic Magnetic Bead Assay for Cell Detection.

    PubMed

    Liu, Fan; KC, Pawan; Zhang, Ge; Zhe, Jiang

    2016-01-01

    We present a novel cell detection device based on a magnetic bead cell assay and microfluidic Coulter counting technology. The device cannot only accurately measure cells size distribution and concentration but also detect specific target cells. The device consists of two identical micro Coulter counters separated by a fluid chamber where an external magnetic field is applied. Antibody-functionalized magnetic beads were bound to specific antigens expressed on the target cells. A high-gradient magnetic field was applied to the chamber closer to the second counter via an external cylindrical magnet. Because of the magnetic interaction between the magnetic beads and the magnetic field, target cells were retarded by the magnetic field; transit time of a target cell (bound with magnetic beads) passing through the second counter was longer than that through the first counter. In comparison, transit times of a nontarget cell remained nearly the same when it passed through both counters. Thus, from the transit time delay we can identify target cells and quantify their concentration in a cell suspension. The transit time and the size of each cell were accurately measured in terms of the width and amplitude of the resistive pulses generated from the two Coulter counters. Experiments demonstrated that for mixed cells with various target cell ratios, the transit time delay increased approximately linearly with the increasing target cell ratio. The limit of detection (LOD) of the assay was estimated to be 5.6% in terms of target cell ratio. Cell viability tests further demonstrated that most cells were viable after the detection. With the simple device configuration and easy sample preparation, this rapid and reliable method is expected to accurately detect target cells and could be applied to facilitate stem cell isolation and characterization. PMID:26636715

  8. A three-dimensional culture system using alginate hydrogel prolongs hatched cattle embryo development in vitro.

    PubMed

    Zhao, Shuan; Liu, Zhen-Xing; Gao, Hui; Wu, Yi; Fang, Yuan; Wu, Shuai-Shuai; Li, Ming-Jie; Bai, Jia-Hua; Liu, Yan; Evans, Alexander; Zeng, Shen-Ming

    2015-07-15

    No successful method exists to maintain the three-dimensional architecture of hatched embryos in vitro. Alginate, a linear polysaccharide derived from brown algae, has characteristics that make it an ideal material as a three-dimensional (3D) extracellular matrix for in vitro cell, tissue, or embryo culture. In this study, alginate hydrogel was used for IVC of posthatched bovine embryos to observe their development under the 3D system. In vitro-fertilized and parthenogenetically activated posthatched bovine blastocysts were cultured in an alginate encapsulation culture system (AECS), an alginate overlay culture system (AOCS), or control culture system. After 18 days of culture, the survival rate of embryos cultured in AECS was higher than that in the control group (P < 0.05), and the embryos were expanded and elongated in AECS with the maximal length of 1.125 mm. When the AECS shrinking embryos were taken out of the alginate beads on Day 18 and cultured in the normal culture system, 9.09% of them attached to the bottoms of the plastic wells and grew rapidly, with the largest area of an attached embryo being 66.00 mm(2) on Day 32. The embryos cultured in AOCS developed monovesicular or multivesicular morphologies. Total cell number of the embryos cultured in AECS on Day 19 was significantly higher than that of embryos on Day 8. Additionally, AECS and AOCS supported differentiation of the embryonic cells. Binuclear cells were visible in Day-26 adherent embryos, and the messenger RNA expression patterns of Cdx2 and Oct4 in AOCS-cultured embryos were similar to those in vivo embryos, whereas IFNT and ISG15 messenger RNA were still expressed in Day-26 and Day-32 prolong-cultured embryos. In conclusion, AECS and AOCS did support cell proliferation, elongation, and differentiation of hatched bovine embryos during prolonged IVC. The culture system will be useful to further investigate the molecular mechanisms controlling ruminant embryo elongation and implantation. PMID

  9. 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

  10. Development of cloxacillin loaded multiple-unit alginate-based floating system by emulsion-gelation method.

    PubMed

    Malakar, Jadupati; Nayak, Amit Kumar; Pal, Dilipkumar

    2012-01-01

    This work investigates the development, optimization and in vitro evaluation of liquid paraffin-entrapped multiple-unit alginate-based floating system containing cloxacillin by emulsion-gelation method for gastro retentive delivery. The effect of process variables like drug to polymer ratio by weight, and liquid paraffin to water ratio by volume on various physicochemical properties in case of liquid paraffin-entrapped calcium alginate beads containing cloxacillin applicable to drug entrapment efficiency, density and drug release was optimized using 3(2) factorial design and analyzed using response surface methodology. The observed (actual values) responses were coincided well with the predicted values, given by the optimization technique. The optimized beads showed drug entrapment efficiency of 64.63±0.78%, density of 0.90±0.05 g/cm(3), and drug release of 56.72±0.85% in simulated gastric fluid (pH 1.2) after 8h with floating lag time of 8.45 min and floated well over 12h in simulated gastric fluid (pH 1.2). The average size of all dried beads ranged from 1.73±0.04 to 1.97±0.08 mm. The beads were characterized by SEM and FTIR for surface morphology and excipients-drug interaction analysis, respectively. All these beads showed prolonged sustained release of cloxacillin over 8h in simulated gastric fluid (pH 1.2). The cloxacillin release profile from liquid paraffin beads followed Korsmeyer-Peppas model over a period of 8h with anomalous (non-Fickian) diffusion mechanism for drug release. PMID:22020191

  11. Optimal production of 4-deoxy-L-erythro-5-hexoseulose uronic acid from alginate for brown macro algae saccharification by combining endo- and exo-type alginate lyases.

    PubMed

    Wang, Da Mao; Kim, Hee Taek; Yun, Eun Ju; Kim, Do Hyoung; Park, Yong-Cheol; Woo, Hee Chul; Kim, Kyoung Heon

    2014-10-01

    Algae are considered as third-generation biomass, and alginate is the main component of brown macroalgae. Alginate can be enzymatically depolymerized by alginate lyases into uronate monomers, such as mannuronic acid and guluronic acid, which are further nonenzymatically converted to 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). We have optimized an enzymatic saccharification process using two recombinant alginate lyases, endo-type Alg7D and exo-type Alg17C, for the efficient production of DEH from alginate. When comparing the sequential and simultaneous additions of Alg7D and Alg17C, it was found that the final yield of DEH was significantly higher when the enzymes were added sequentially. The progress of saccharification reactions and production of DEH were verified by thin layer chromatography and gas chromatography-mass spectrometry, respectively. Our results showed that the two recombinant enzymes could be exploited for the efficient production of DEH that is the key substrate for producing biofuels from brown macro algal biomass. PMID:24794171

  12. 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

  13. Alginic Acid Accelerates Calcite Dissolution

    NASA Astrophysics Data System (ADS)

    Perry, T. D.; Duckworth, O. W.; McNamara, C. J.; Martin, S. T.; Mitchell, R.

    2003-12-01

    Accelerated carbonate weathering through biological activity affects both geochemical cycling and the local pH and alkalinity of terrestrial and marine waters. Microbes affect carbonate dissolution through metabolic activity, production of acidic or chelating exudates, and cation binding by cell walls. Dissolution occurs within microbial biofilms - communities of microorganisms attached to stone in an exopolymer matrix. We investigated the effect of alginic acid, a common biological polymer produced by bacteria and algae, on calcite dissolution using a paired atomic force microscopy/flow-through reactor apparatus. The alginic acid caused up to an order of magnitude increase in dissolution rate at 3 < pH < 12. Additionally, the polymer preferentially binds to the obtuse pit steps and increases step velocity. We propose that the polymer is actively chelating surficial cations reducing the activation energy and increasing dissolution rate. The role of biologically produced polymers in mineral weathering is important in the protection of cultural heritage materials and understanding of marine and terrestrial systems.

  14. 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.

  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. 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.

  17. Alginate-immobilized bentonite clay: adsorption efficacy and reusability for Cu(II) removal from aqueous solution.

    PubMed

    Tan, Wei Shang; Ting, Adeline Su Yien

    2014-05-01

    This study evaluated the use of alginate-immobilized bentonite to remove Cu(II) as an alternative to mitigate clogging problems. The adsorption efficacy (under the influence of time, pH and initial Cu(II) concentration) and reusability of immobilized-bentonite (1% w/v bentonite) was tested against plain alginate beads. Results revealed that immobilized bentonite demonstrated significantly higher sorption efficacy compared to plain alginate beads with 114.70 and 94.04 mg Cu(II) adsorbed g(-1) adsorbent, respectively. Both sorbents were comparable in other aspects where sorption equilibrium was achieved within 6 h, with optimum pH between pH 4 and 5 for adsorption, displayed maximum adsorption capacity at initial Cu(II) concentrations of 400 mg l(-1), and demonstrated excellent reusability potential with desorption greater than 90% throughout three consecutive adsorption-desorption cycles. Both sorbents also conformed to Langmuir isotherm and pseudo-second order kinetic model. Immobilized bentonite is therefore recommended for use in water treatments to remove Cu(II) without clogging the system. PMID:24405651

  18. 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. PMID:27068833

  19. 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

  20. 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

  1. Characterization of Antibiotic-Loaded Alginate-Osa Starch Microbeads Produced by Ionotropic Pregelation

    PubMed Central

    Fontes, Gizele Cardoso; Calado, Verônica Maria Araújo; Rossi, Alexandre Malta; da Rocha-Leão, Maria Helena Miguez

    2013-01-01

    The aim of this study was to characterize the penicillin-loaded microbeads composed of alginate and octenyl succinic anhydride (OSA) starch prepared by ionotropic pregelation with calcium chloride and to evaluate their in vitro drug delivery profile. The beads were characterized by size, scanning electron microscopy (SEM), zeta potential, swelling behavior, and degree of erosion. Also, the possible interaction between penicillin and biopolymers was investigated by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The SEM micrograph results indicated a homogeneous drug distribution in the matrix. Also, based on thermal analyses (TGA/DSC), interactions were detected between microbead components. Although FTIR spectra of penicillin-loaded microbeads did not reveal the formation of new chemical entities, they confirmed the chemical drug stability. XRD patterns showed that the incorporated crystalline structure of penicillin did not significantly alter the primarily amorphous polymeric network. In addition, the results confirmed a prolonged penicillin delivery system profile. These results imply that alginate and OSA starch beads can be used as a suitable controlled-release carrier for penicillin. PMID:23862146

  2. 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...

  3. 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. PMID:17643299

  4. Microfluidic production of single micrometer-sized hydrogel beads utilizing droplet dissolution in a polar solvent

    PubMed Central

    Sugaya, Sari; Yamada, Masumi; Hori, Ayaka; Seki, Minoru

    2013-01-01

    In this study, a microfluidic process is proposed for preparing monodisperse micrometer-sized hydrogel beads. This process utilizes non-equilibrium aqueous droplets formed in a polar organic solvent. The water-in-oil droplets of the hydrogel precursor rapidly shrunk owing to the dissolution of water molecules into the continuous phase. The shrunken and condensed droplets were then gelled, resulting in the formation of hydrogel microbeads with sizes significantly smaller than the initial droplet size. This study employed methyl acetate as the polar organic solvent, which can dissolve water at 8%. Two types of monodisperse hydrogel beads—Ca-alginate and chitosan—with sizes of 6–10 μm (coefficient of variation < 6%) were successfully produced. In addition, we obtained hydrogel beads with non-spherical morphologies by controlling the degree of droplet shrinkage at the time of gelation and by adjusting the concentration of the gelation agent. Furthermore, the encapsulation and concentration of DNA molecules within the hydrogel beads were demonstrated. The process presented in this study has great potential to produce small and highly concentrated hydrogel beads that are difficult to obtain by using conventional microfluidic processes. PMID:24396529

  5. Seeds used for Bodhi beads in China

    PubMed Central

    2014-01-01

    Background Bodhi beads are a Buddhist prayer item made from seeds. Bodhi beads have a large and emerging market in China, and demand for the beads has particularly increased in Buddhism regions, especially Tibet. Many people have started to focus on and collect Bodhi beads and to develop a Bodhi bead culture. But no research has examined the source plants of Bodhi beads. Therefore, ethnobotanical surveys were conducted in six provinces of China to investigate and document Bodhi bead plants. Reasons for the development of Bodhi bead culture were also discussed. Methods Six provinces of China were selected for market surveys. Information was collected using semi-structured interviews, key informant interviews, and participatory observation with traders, tourists, and local residents. Barkhor Street in Lhasa was focused on during market surveys because it is one of the most popular streets in China. Results Forty-seven species (including 2 varieties) in 19 families and 39 genera represented 52 types of Bodhi beads that were collected. The most popular Bodhi bead plants have a long history and religious significance. Most Bodhi bead plants can be used as medicine or food, and their seeds or fruits are the main elements in these uses. ‘Bodhi seeds’ have been historically used in other countries for making ornaments, especially seeds of the legume family. Many factors helped form Bodhi bead culture in China, but its foundation was in Indian Buddhist culture. Conclusions As one of the earliest adornment materials, seeds played an important role for human production and life. Complex sources of Bodhi beads have different cultural and historical significance. People bought and collected Bodhi beads to reflect their love and admiration for the plants. Thus, the documentation of Bodhi bead plants can serve as a basis for future investigation of Bodhi bead culture and modern Buddhist culture. PMID:24479788

  6. 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. PMID:27185114

  7. 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

  8. 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.

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

    PubMed

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-12-01

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

  10. 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 %.

  11. 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

  12. 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.

  13. 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

  14. Magnetic bead detection using nano-transformers.

    PubMed

    Kim, Hyung Kwon; Hwang, Jong Seung; Hwang, Sung Woo; Ahn, Doyeol

    2010-11-19

    A novel scheme to detect magnetic beads using a nano-scale transformer with a femtoweber resolution is reported. We have performed a Faraday's induction experiment with the nano-transformer at room temperature. The transformer shows the linear output voltage responses to the sinusoidal input current. When magnetic beads are placed on the transformer, the output responses are increased by an amount corresponding to the added magnetic flux from the beads when compared with the case of no beads on the transformer. In this way, we could determine whether magnetic beads are on top of the transformer in a single particle level. PMID:20972313

  15. 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

  16. 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

  17. Alginate as a displacer for protein displacement chromatography.

    PubMed

    Chen, G; Scouten, W H

    1996-01-01

    Alginate use in displacement chromatography as a displacer has been studied. The experiments showed that untreated alginate is the basis of potential displacer for displacement chromatography, but needs to be cleaved into smaller chains. Alginate treated with ultrasound, which cleaves alginate into shorter polysaccharide chains, gave better displacement than untreated alginate, while alginate subjected to limited acid hydrolysis gave the best results in displacement chromatography. It was found that the mixture of ovalbumin and beta-lactoglobulin separated well, and several components of ovalbumin were also separated and purified when alginate hydrolysate was used as a displacer. beta-Lactoglobulins A and B, which have the same molecular weight and differ in isoelectric point by only 0.1 pH units, were displaced from Q-Sepharose by alginate hydrolysate. PMID:9174919

  18. Diffusion of Cu2+ in calcium alginate gel beads: further analyses.

    PubMed

    Chaiken, R F

    1995-03-01

    The diffusivity of Cu(2+), as determined by previous authors from analysis of experimental data in terms of the shrinking core (SCM) and linear absorption (LAM) models, is examined in light of the ability of the models to curve fit all the data. It is concluded from this further analysis that previous conclusions depicting the LAM to have an advantage over the SCM for predictive value are not justified. It is also shown that equally good curve fits can be obtained with a recent absorption/desorption model of diffusion which considers directly, through distribution theory, the effect of heterogeneity of material properties on the rate of diffusion. PMID:18623239

  19. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Propylene glycol alginate. 172.858 Section 172.858... Propylene glycol alginate. The food additive propylene glycol alginate (CAS Reg. No. 9005-37-2) may be used... the act: (1) The name of the additive, “propylene glycol alginate” or “propylene glycol ester...

  20. 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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  3. Application of self-assembled ultra-thin film coatings to stabilize macromolecule encapsulation in alginate microspheres.

    PubMed

    Srivastava, R; McShane, M J

    2005-06-01

    Alginate-based hydrogels have several unique properties that have enabled them to be used as a matrix for the entrapment of a variety of enzymes, proteins and cells for applications in bioprocessing, drug delivery and chemical sensing. However, control over release rates or, in some cases, stable encapsulation remains a difficult goal, especially for small particles with high surface-area-to-volume ratios. In this work, the potential to limit diffusion of macromolecules embedded in alginate spheres with nanofilm coatings was assessed. Alginate microspheres were fabricated using an emulsification process with high surfactant concentration to form beads in the size range of 2-10 microm. Using calcium chloride for ionotropic gelation, dextran was encapsulated in the gel phase by mixing with the alginate in solution. The exterior surface was then modified with polyelectrolyte coatings using the layer-by-layer self assembly technique. Leaching studies to assess retention of dextran with varying molecular weights confirmed that the application of multi-layer thin films to the alginate microspheres was effective in reducing leaching rate and total loss of the encapsulated material from the microspheres. For the best case, the rate of release for dextran of 2,000,000 Dalton molecular weight decreased from 1% h(-1) in bare microspheres to 0.1% h(-1) in polyelectrolyte-coated microspheres. The effectiveness of nanofilms reducing loss of the encapsulated macromolecules was found to vary between different polycation materials used. These studies support the feasibility of using these microsystems for development of long-term stable encapsulated systems, such as implantable biosensors. PMID:16214787

  4. 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.

  5. Review article: alginate-raft formulations in the treatment of heartburn and acid reflux.

    PubMed

    Mandel, K G; Daggy, B P; Brodie, D A; Jacoby, H I

    2000-06-01

    Alginate-based raft-forming formulations have been marketed word-wide for over 30 years under various brand names, including Gaviscon. They are used for the symptomatic treatment of heartburn and oesophagitis, and appear to act by a unique mechanism which differs from that of traditional antacids. In the presence of gastric acid, alginates precipitate, forming a gel. Alginate-based raft-forming formulations usually contain sodium or potassium bicarbonate; in the presence of gastric acid, the bicarbonate is converted to carbon dioxide which becomes entrapped within the gel precipitate, converting it into a foam which floats on the surface of the gastric contents, much like a raft on water. Both in vitro and in vivo studies have demonstrated that alginate-based rafts can entrap carbon dioxide, as well as antacid components contained in some formulations, thus providing a relatively pH-neutral barrier. Several studies have demonstrated that the alginate raft can preferentially move into the oesophagus in place, or ahead, of acidic gastric contents during episodes of gastro-oesophageal reflux; some studies further suggest that the raft can act as a physical barrier to reduce reflux episodes. Although some alginate-based formulations also contain antacid components which can provide significant acid neutralization capacity, the efficacy of these formulations to reduce heartburn symptoms does not appear to be totally dependent on the neutralization of bulk gastric contents. The strength of the alginate raft is dependant on several factors, including the amount of carbon dioxide generated and entrapped in the raft, the molecular properties of the alginate, and the presence of aluminium or calcium in the antacid components of the formulation. Raft formation occurs rapidly, often within a few seconds of dosing; hence alginate-containing antacids are comparable to traditional antacids for speed of onset of relief. Since the raft can be retained in the stomach for several

  6. Interaction of peptide-bound beads with lipopolysaccharide and lipoproteins.

    PubMed

    Suzuki, Masatsugu M; Matsumoto, Megumi; Omi, Hiroyuki; Kobayashi, Tomomi; Nakamura, Akio; Kishi, Hiroko; Kobayashi, Sei; Takagi, Takashi

    2014-05-01

    We previously reported the generation of lipopolysaccharide (LPS)-binding peptides by phage display and chemical modification. Among them, a dodecapeptide designated Li5-025 (K'YSSSISSIRAC'; K' and C' denote d-lysine and d-cysteine, respectively) showed a high binding affinity for LPS and was resistant to protease digestion (Suzuki et al., 2010). In the current study, Li5-025-bound silica beads, hereafter referred to as P-beads, were generated and found to be devoid of LPS-neutralizing activity. Thus, LPS bound to the P-beads could be directly used in the Limulus amebocyte lysate (LAL) assay. P-beads bound LPS dissolved in solutions of ethanol, pH4, pH10, and 0.5M NaCl and LPS bound to the P-beads was quantitatively assayed. The sensitivity of this assay was observed to be approximately 0.1pg/mL LPS. P-beads bound LPS dissolved in antithrombin III (AT III) solution which is a strong inhibitor of activated factors C and B as well as the clotting enzyme in the LAL assay; the inhibitory effect of AT III was completely reversed upon washing the P-beads with 25% acetonitrile. This was employed as the first step for the detection of free LPS in plasma using the LAL assay. LPS added to human plasma at 0°C followed by application to the P-beads and subsequent washing with 25% acetonitrile resulted in low LPS activity as detected by the LAL assay. However, further washing of the P-beads with 0.1% Triton X100 in 25% acetonitrile resulted in high LPS activity. This is the first instance of quantitative detection of free LPS in plasma using the LAL assay, and the sensitivity of this method was observed to be 1pg/mL of LPS. The proteins eluted in the 0.1% Triton X-100 wash were analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Two protein bands of 28kDa and 18kDa were predominantly observed. Mass spectrometry analysis revealed that the 28kDa and 18kDa bands corresponded to apolipoprotein A-I (apoA-I) and apolipoprotein A-II (apoA-II), respectively. Apo

  7. Fermentation and microencapsulation of the nematophagous fungus Hirsutella rhossiliensis in a novel type of hollow beads.

    PubMed

    Patel, Anant V; Jakobs-Schönwandt, Desiree; Rose, Thomas; Vorlop, Klaus-Dieter

    2011-03-01

    In this work, fermentation and formulation aspects of the nematophagous fungus Hirsutella rhossiliensis BBA were investigated. When incubated in 2% (w/w) glucose and 0.5% (w/w) yeast extract medium in a 1-L Erlenmeyer flask without baffles, heavy pellet formation was observed. Only 40% of the mycelium had a size less than 500 μm. When a flask with three baffles was used, the portion of mycelium <500 μm rose to 95%. In the next step, the influence of aeration rate and stirrer speed on production of finely dispersed mycelium in a stirred tank reactor was investigated. The best fermentation results were obtained at 0.4 vvm and 400 rpm stirrer speed with 90% mycelium <500 μm and 5 g/L biomass. Then, mycelium was microencapsulated in hollow beads based on sulfoethylcellulose (SEC). Experiments on the capsule nutrient reservoir showed that 15% (w/w) corn gluten and 0.5% (w/w) yeast extract could be replaced with 3% (w/w) autoclaved baker's yeast which was never used as capsule additive before. Radial growth of mycelium out of dried hollow beads containing 1% (w/w) biomass and 3% (w/w) baker's yeast was faster than for alginate beads containing equivalent amounts of biomass and yeast indicating a higher bio-control potential. PMID:21181150

  8. 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.

  9. 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.

  10. Multifunctional cellulose beads and their interaction with gram positive bacteria.

    PubMed

    Blachechen, Leandro S; Fardim, Pedro; Petri, Denise F S

    2014-09-01

    Cellulose beads with ∼3 mm of diameter and high circularity were obtained by dripping cellulose solutions (5, 6, and 7 wt %) dissolved in NaOH7%/urea12%, into HCl 2 M coagulation bath. Carboxylic groups were generated on beads surface through NaClO/NaClO2/TEMPO oxidation method, achieving total charge density of ∼0.77 mmol/g. Pristine (CB) and oxidized (OCB) beads were characterized by means of optical images analyses, scanning electron microscopy (SEM) and compression tests. Both types of beads, CB and OCB, were used as adsorbent for poly(4-vinyl-N-pentylpyridinium) bromide, QPVP-C5, a bactericidal agent. The adsorption of QPVP-C5 on CB and OCB was evaluated by means of FTIR-ATR, UV-vis, CHN elemental analyses, and X-ray photoelectron spectroscopy (XPS). The adsorbed amount of QPVP-C5 was remarkably higher on OCB than on CB due to ionic interactions. Desorption was less than 5%. The interaction between neat OCB or OCB coated and two different amounts of QPVP-C5 and Gram-positive bacteria Micrococcus luteus was assessed by changes in turbidimetry, SEM, and elemental analyses. Bacteria adsorbed on the surface of neat OCB and weakly QPVP-C5 coated OCB due to hydrogen bonding or ion-dipole interaction. Notorious bactericidal action was observed for OCB samples coated with large amount of QPVP-C5. PMID:25100636

  11. Beautiful Beads: A Lesson in Making Beads with Friendly Clay. AMACO[R] Lesson.

    ERIC Educational Resources Information Center

    Gamble, Harriet; Gamble, David

    This lesson resource includes a brief summary of the history of bead making and historic fascination with beads as adornment. A focus on design elements, color theory, craftsmanship, and technical skill in bead making is encouraged. The plan includes lesson goals and objectives; background preparation; a glossary of terms; a list of supplies; and…

  12. 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

  13. 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 and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  14. 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...

  15. 21 CFR 184.1133 - Ammonium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 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 FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  16. 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 and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  17. 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 and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  18. 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.

  19. A highly efficient bead extraction technique with low bead number for digital microfluidic immunoassay.

    PubMed

    Huang, Cheng-Yeh; Tsai, Po-Yen; Lee, I-Chin; Hsu, Hsin-Yun; Huang, Hong-Yuan; Fan, Shih-Kang; Yao, Da-Jeng; Liu, Cheng-Hsien; Hsu, Wensyang

    2016-01-01

    Here, we describe a technique to manipulate a low number of beads to achieve high washing efficiency with zero bead loss in the washing process of a digital microfluidic (DMF) immunoassay. Previously, two magnetic bead extraction methods were reported in the DMF platform: (1) single-side electrowetting method and (2) double-side electrowetting method. The first approach could provide high washing efficiency, but it required a large number of beads. The second approach could reduce the required number of beads, but it was inefficient where multiple washes were required. More importantly, bead loss during the washing process was unavoidable in both methods. Here, an improved double-side electrowetting method is proposed for bead extraction by utilizing a series of unequal electrodes. It is shown that, with proper electrode size ratio, only one wash step is required to achieve 98% washing rate without any bead loss at bead number less than 100 in a droplet. It allows using only about 25 magnetic beads in DMF immunoassay to increase the number of captured analytes on each bead effectively. In our human soluble tumor necrosis factor receptor I (sTNF-RI) model immunoassay, the experimental results show that, comparing to our previous results without using the proposed bead extraction technique, the immunoassay with low bead number significantly enhances the fluorescence signal to provide a better limit of detection (3.14 pg/ml) with smaller reagent volumes (200 nl) and shorter analysis time (<1 h). This improved bead extraction technique not only can be used in the DMF immunoassay but also has great potential to be used in any other bead-based DMF systems for different applications. PMID:26858807

  20. Porous bead packings for gas chromatography

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.; Woeller, F. H.

    1979-01-01

    Porous polyaromatic packing beads have low polarity, high efficiency, short retention time, and may be synthesized in size range of 50 to 150 micrometers (100 to 270 mesh). Mechanically strong beads may be produced using various materials depending on elements and compounds to be identified.

  1. 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. PMID:25020082

  2. Formation of Apollo 15 green glass beads

    NASA Astrophysics Data System (ADS)

    Arndt, J.; Engelhardt, W. V.; Gonzalez-Cabeza, I.; Meier, B.

    1984-11-01

    The results of an analysis of the thermal history of green glass beads extracted from breccia 15427 in the north rim of Spur crater are reported. The vitrophyric beads were found to have lattice, fiber and polyhedral olivine morphologies. Cooling, heating, and crystallization experiments were performed with synthetically produced glass beads with the same compositions as the natural beads. The data indicated that the breccia samples cooled from 1000-1050 C at 1 C/sec, less than in free flight conditions. The homogeneity of the beads rules out solid rock impacts. The required cooling rate suggests that the process occurred in an atmosphere of volcanic gases. The suspension would have had to last at least 10 minutes.

  3. Size of the Dynamic Bead in Polymers

    SciTech Connect

    Agapov, Alexander L; Sokolov, Alexei P

    2010-01-01

    Presented analysis of neutron, mechanical, and MD simulation data available in the literature demonstrates that the dynamic bead size (the smallest subchain that still exhibits the Rouse-like dynamics) in most of the polymers is significantly larger than the traditionally defined Kuhn segment. Moreover, our analysis emphasizes that even the static bead size (e.g., chain statistics) disagrees with the Kuhn segment length. We demonstrate that the deficiency of the Kuhn segment definition is based on the assumption of a chain being completely extended inside a single bead. The analysis suggests that representation of a real polymer chain by the bead-and-spring model with a single parameter C cannot be correct. One needs more parameters to reflect correctly details of the chain structure in the bead-and-spring model.

  4. 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

  5. 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. PMID:9292438

  6. 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). PMID:25970641

  7. 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

  8. 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

  9. Glucose and lactose as cryoprotectants for fungal strains immobilised in sodium alginate: an emphasis on the conservation of the zygomycetes Rhizopus and Mucor.

    PubMed

    Rocha, Marcos F G; Lima, Daniel T; Brilhante, Raimunda S N; Cordeiro, Rossana A; Monteiro, André J; Teixeira, Carlos E C; Ribeiro, Joyce F; Castelo-Branco, Débora S C M; Sidrim, José J C

    2013-05-01

    This research aimed at investigating the cryoprotectant action of glucose and lactose on strains of Malassezia spp. and zygomycetes immobilised in sodium alginate. Twelve strains of Malassezia spp. (nine M. furfur, two M. globosa and one M. sympodialis) and 12 zygomycetes (five Rhizopus oryzae and seven Mucor hiemales) were immobilised in sodium alginate, within plastic beads, maintained in appropriate media containing glucose and lactose at concentrations of 9% and 23% and preserved at temperatures of -20 and -80 °C. Strain viability was evaluated from 15 to 270 days of storage, through the observation of macro-micromorphologic characteristics. The Malassezia spp. strains were only viable until 90 days of storage, whereas for zygomycetes, viable strains were observed until after 270 days of storage at -80 °C, in the media containing 23% glucose or lactose. The use of 23% glucose or lactose at -80 °C in a sodium alginate cell immobilisation system is efficient for cryopreserving zygomycetes. This research creates perspectives for the use of glucose and lactose in sodium alginate cell immobilisation systems for the preservation of fungi with low viability. PMID:23278948

  10. Arming embolic beads with anti-VEGF antibodies and controlling their release using LbL technology.

    PubMed

    Sakr, O S; Berndt, S; Carpentier, G; Cuendet, M; Jordan, O; Borchard, G

    2016-02-28

    Transarterial chemoembolization (TACE) is used to treat various types of hypervascular tumors such as hepatocellular carcinoma and renal cancer. However, embolization and blocking of blood vessels nourishing a tumor mass evokes an angiogenic response due to the secretion of vascular endothelial growth factor (VEGF), which results in the formation of new blood vessels and eventually limitation in therapeutic efficacy. The presented work investigates the feasibility of loading the clinically used embolic beads (DC Bead®) with Bevacizumab (BEV), an anti-VEGF antibody, and control its release kinetics via Layer-by-Layer (LbL) coating. This strategy has the aim to achieve high, localized and sustained concentrations of BEV at the tumor site and reduce drug exposure in the systemic circulation. High loading of BEV on lyophilized beads of about 76mg BEV/bead vial was achieved. LbL coating was carried out by depositing alternating layers of the biocompatible polymers alginate and poly-L-lysine. Coating was proven successful by monitoring the reversal of zeta potential after addition of each layer. Morphological changes of the bead surface before and after coating were illustrated using SEM imaging. Moreover, release profiles from different formulations were studied and results showed that optimizing the number of deposited layers effectively slows the release of BEV for three days. Activity of released BEV was studied in different 2D and 3D cell based assays. Released BEV fractions showed comparable activity to fresh BEV solution used as control after 3days. In conclusion, our results suggest the opportunity for loading anti-VEGF antibodies on commercially available embolic beads to increase the efficacy of TACE of hypervascular tumors. PMID:26780173

  11. 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

  12. Stability of gold bead tissue markers.

    PubMed

    Miller, Joel M; Rossi, Ethan A; Wiesmair, Martin; Alexander, Danielle E; Gallo, Orazio

    2006-01-01

    Significant soft tissue features in the orbit and elsewhere are not resolved by MRI or any other imaging method. We describe a new method that uses tiny ( approximately 0.1 mm diameter) gold beads as markers to visualize movements of such tissues with high spatial resolution ( approximately 100 microm) and moderate temporal resolution ( approximately 100 ms). We describe bead fabrication, implantation, imaging, and image processing to extract three-dimensional bead coordinates. We then present results of an experiment to determine the stability of gold bead tissue markers (GBTMs) over time in normally moving orbital tissues. Most beads (76%) implanted in sclera, muscle, tendon, and connective tissue were highly stable over the 6-month measurement period. Beads that were judged unstable drifted only a few 100 microm. Bead flows with gaze suggested that posterior Tenon's capsule moves with the globe, that the lateral rectus belly may sideslip, producing "bridle forces," and that the posterior medial rectus pulley sling moves freely anteriorly and posteriorly, but hardly vertically, as required by the "coordinated active pulley" hypothesis. The GBTM method seems applicable to study such short time course phenomena as extraocular muscle (EOM) and connective tissue movement as a function of gaze and such long time course phenomena as myopic eye growth. PMID:16881792

  13. 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.

  14. 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

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

    PubMed

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

    2016-05-01

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

  16. 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. PMID:26249587

  17. The comparative bioavailability of cimetidine-alginate treatments.

    PubMed

    Britton, A M; Nichols, J D; Draper, P R

    1991-02-01

    The comparative bioavailability of cimetidine in cimetidine-alginate combinations has been investigated in twelve healthy volunteers in an open crossover study. Each volunteer received a single oral dose of a commercially available alginate-cimetidine combination tablet (Algitec) or cimetidine tablets (Tagamet), co-administered with a commercially available alginate reflux suppressant liquid or tablet (Gaviscon). No significant differences were observed between treatments for Cmax, tmax, AUC0-12 or AUC0- infinity. The study demonstrated equivalent bioavailability of cimetidine when administered separately with alginate products and as a fixed dose combination product. PMID:1672897

  18. 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

  19. Genetic manipulation of human mesenchymal progenitors to promote chondrogenesis using "bead-in-bead" polysaccharide capsules.

    PubMed

    Babister, Jodie C; Tare, Rahul S; Green, David W; Inglis, Stefanie; Mann, Stephen; Oreffo, Richard O C

    2008-01-01

    Articular cartilage defects arising from trauma or degenerative diseases fail to repair spontaneously. We have adopted a non-viral gene delivery and tissue engineering strategy, in which Sox-9 transfected human mesenchymal progenitors have been encapsulated within alginate/chitosan polysaccharide capsules to promote chondrogenesis. Human bone marrow stromal cells and articular chondrocytes were transfected with flag-tagged Sox-9 plasmid and after 7 days in static culture, large regions of cell-generated matrix containing cartilage proteoglycans were observed as confirmed by positive Alcian blue staining and Sox-9 immunohistochemistry. Further, after 28 days, in vitro and in vivo, samples encapsulated with Sox-9 transfected cells demonstrated large regions of cartilaginous matrix as confirmed by positive Alcian blue staining, Sox-9 and type-II collagen immunohistochemistry, absent in samples encapsulated with untransfected cells. Extracted protein from in vivo constructs was further assessed by western blot analysis and positive expression of Sox-9 and type-II collagen was observed in Sox-9 transfected constructs which was absent in untransfected cells. Regions of cartilage-like matrix were significantly increased in Sox-9 constructs in comparison with untransfected constructs, confirming Sox-9 gene delivery enhances chondrogenesis in targeted cell populations, outlining the potential to promote cartilaginous construct formation with therapeutic implications for regeneration of human articular cartilage tissue defects. PMID:17897711

  20. Janus-compartmental alginate microbeads having polydiacetylene liposomes and magnetic nanoparticles for visual lead(II) detection.

    PubMed

    Kang, Do Hyun; Jung, Ho-Sup; Ahn, Namyoung; Yang, Su Min; Seo, Sungbaek; Suh, Kahp-Yang; Chang, Pahn-Shick; Jeon, Noo Li; Kim, Jinsang; Kim, Keesung

    2014-07-01

    Janus-compartmental alginate microbeads having two divided phases of sensory polydiacetylene (PDA) liposomes and magnetic nanoparticles were fabricated for facile sensory applications. The sensory liposomes are composed of PDA for label-free signal generation and 1,2-dipalmitoyl-sn-glycero-3-galloyl (DPGG) lipids whose galloyl headgroup has specific interactions with lead(II). The second phase having magnetic nanoparticles is designed for convenient handling of the microbeads, such as washing, solvent exchange, stirring, and detection, by applying magnetic field. Selective and convenient colorimetric detection of lead(II) and efficient removal of lead(II) by alginate matrix at the same time are demonstrated. PMID:24926923

  1. 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

  2. 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)

  3. Plating by glass-bead peening

    NASA Technical Reports Server (NTRS)

    Babecki, A. J.; Haehner, C. L.

    1971-01-01

    Technique permits plating of primarily metallic substrates with either metals or nonmetals at normal temperature. Peening uses compressed air to apply concurrent streams of small glass beads and powdered plating material to the substrate.

  4. 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. PMID:24810435

  5. 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.

  6. Acupressure Bead in the Eustachian Tube.

    PubMed

    Igarashi, Kazunori; Matsumoto, Yu; Kakigi, Akinobu

    2015-08-01

    In this article, we aim to enlighten practitioners and patients involved with acupressure beads and to contribute to their safer use by reporting a unique case of insidious intrusion of an acupressure bead into the eustachian tube. A metallic object was found in the eustachian tube of a patient while conducting a magnetic resonance imaging (MRI) examination. The object was later confirmed to be an auricular acupressure bead, and was successfully removed by performing a tympanoplasty and a canal wall down mastoidectomy. The bead was assumed to have passed through an existing perforation of the tympanic membrane. According to previously published literature, tympanic membrane perforations exist in ∼1% of the population. Therefore, middle-ear foreign bodies are relatively common occurrences for otolaryngologists. However, metallic objects such as acupressure beads are especially important in the sense that they can cause severe burns during MRI. To avoid potential complications, acupressure-bead practitioners should be aware of the possibility that intrusions through the tympanic membrane could go unnoticed. PMID:26276456

  7. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or...

  8. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  9. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or...

  10. 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.

  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. Efficient estimation of contact probabilities from inter-bead distance distributions in simulated polymer chains

    NASA Astrophysics Data System (ADS)

    Meluzzi, Dario; Arya, Gaurav

    2015-02-01

    The estimation of contact probabilities (CP) from conformations of simulated bead-chain polymer models is a key step in methods that aim to elucidate the spatial organization of chromatin from analysis of experimentally determined contacts between different genomic loci. Although CPs can be estimated simply by counting contacts between beads in a sample of simulated chain conformations, reliable estimation of small CPs through this approach requires a large number of conformations, which can be computationally expensive to obtain. Here we describe an alternative computational method for estimating relatively small CPs without requiring large samples of chain conformations. In particular, we estimate the CPs from functional approximations to the cumulative distribution function (cdf) of the inter-bead distance for each pair of beads. These cdf approximations are obtained by fitting the extended generalized lambda distribution (EGLD) to inter-bead distances determined from a sample of chain conformations, which are in turn generated by Monte Carlo simulations. We find that CPs estimated from fitted EGLD cdfs are significantly more accurate than CPs estimated using contact counts from samples of limited size, and are more precise with all sample sizes, permitting as much as a tenfold reduction in conformation sample size for chains of 200 beads and samples smaller than 105 conformations. This method of CP estimation thus has potential to accelerate computational efforts to elucidate the spatial organization of chromatin.

  13. Efficient estimation of contact probabilities from inter-bead distance distributions in simulated polymer chains.

    PubMed

    Meluzzi, Dario; Arya, Gaurav

    2015-02-18

    The estimation of contact probabilities (CP) from conformations of simulated bead-chain polymer models is a key step in methods that aim to elucidate the spatial organization of chromatin from analysis of experimentally determined contacts between different genomic loci. Although CPs can be estimated simply by counting contacts between beads in a sample of simulated chain conformations, reliable estimation of small CPs through this approach requires a large number of conformations, which can be computationally expensive to obtain. Here we describe an alternative computational method for estimating relatively small CPs without requiring large samples of chain conformations. In particular, we estimate the CPs from functional approximations to the cumulative distribution function (cdf) of the inter-bead distance for each pair of beads. These cdf approximations are obtained by fitting the extended generalized lambda distribution (EGLD) to inter-bead distances determined from a sample of chain conformations, which are in turn generated by Monte Carlo simulations. We find that CPs estimated from fitted EGLD cdfs are significantly more accurate than CPs estimated using contact counts from samples of limited size, and are more precise with all sample sizes, permitting as much as a tenfold reduction in conformation sample size for chains of 200 beads and samples smaller than 10(5) conformations. This method of CP estimation thus has potential to accelerate computational efforts to elucidate the spatial organization of chromatin. PMID:25563926

  14. 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.

  15. Aerogel beads as cryogenic thermal insulation system

    NASA Astrophysics Data System (ADS)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.

    2002-05-01

    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/m3) 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 10-5 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.

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

    PubMed

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

    2016-08-20

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

  17. Transport of Beads by Several Kinesin Motors

    PubMed Central

    Beeg, Janina; Klumpp, Stefan; Dimova, Rumiana; Gracià, Rubèn Serral; Unger, Eberhard; Lipowsky, Reinhard

    2008-01-01

    The movements of beads pulled by several kinesin-1 (conventional kinesin) motors are studied both theoretically and experimentally. While the velocity is approximately independent of the number of motors pulling the beads, the walking distance or run-length is strongly increased when more motors are involved. Run-length distributions are measured for a wide range of motor concentrations and matched to theoretically calculated distributions using only two global fit parameters. In this way, the maximal number of motors pulling the beads is estimated to vary between two and seven motors for total kinesin concentrations between 0.1 and 2.5 μg/ml or between 0.27 and 6.7 nM. In the same concentration regime, the average number of pulling motors is found to lie between 1.1 and 3.2 motors. PMID:17872957

  18. Transport of beads by several kinesin motors.

    PubMed

    Beeg, Janina; Klumpp, Stefan; Dimova, Rumiana; Gracià, Rubèn Serral; Unger, Eberhard; Lipowsky, Reinhard

    2008-01-15

    The movements of beads pulled by several kinesin-1 (conventional kinesin) motors are studied both theoretically and experimentally. While the velocity is approximately independent of the number of motors pulling the beads, the walking distance or run-length is strongly increased when more motors are involved. Run-length distributions are measured for a wide range of motor concentrations and matched to theoretically calculated distributions using only two global fit parameters. In this way, the maximal number of motors pulling the beads is estimated to vary between two and seven motors for total kinesin concentrations between 0.1 and 2.5 microg/ml or between 0.27 and 6.7 nM. In the same concentration regime, the average number of pulling motors is found to lie between 1.1 and 3.2 motors. PMID:17872957

  19. Effectiveness of salt versus glass bead sterilizers.

    PubMed

    Haddad, A J; Girard, B; Bouclin, R; Valois, M; Landry, R G

    1997-06-01

    Microorganisms can be removed from dental instruments by various methods, including treatment in salt and glass bead sterilizers. However, no rigorous, controlled, in vivo or in vitro studies have been performed to verify the respective efficiencies of these methods. The goals of this study were to determine if the positioning of instruments at the centre or edge of a salt sterilizer results in differential sterilization effectiveness, and to compare the effectiveness of salt sterilizers relative to glass bead sterilizers. Autoclaved number 60 reamers were contaminated by plunging them to the handle in a commercial Bacillus stearothermophilus spore suspension. They were then sterilized for different periods of time and at different positions in the sterilizers. Each experiment included positive and negative controls. The results showed that better sterilization is achieved at the edge of the chamber than at the centre, and that salt sterilizers are more effective than glass bead sterilizers for a given period of time (15 seconds) in the sterilizer. PMID:9203778

  20. 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

  1. Molecular engineering of manipulated alginate-based polyurethanes.

    PubMed

    Daemi, Hamed; Barikani, Mehdi

    2014-11-01

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

  2. 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.

  3. Rheological characterization of a gel produced using human blood plasma and alginate mixtures.

    PubMed

    Malagón-Romero, Dionisio; Hernández, Nicolás; Cardozo, Carmen; Godoy-Silva, Rubén D

    2014-06-01

    Human blood plasma is a material used to generate tissue equivalents due to presence of fibrinogen. However, gels formed using human blood plasma has weak mechanical properties. In this study, different mixtures of sodium alginate and blood plasma were performed and evaluated. By determining ζ potential can be established the stability of the plasma-alginate mixture and by dynamic rheology can determine the most suitable parameters for the gelation of the above mixtures, when calcium chloride is used as a crosslinker. Experimental results evidence an increment in ζ potential at alginate concentrations of 0.8% and 1.6% with a resulting pseudoplastic behavior of evaluated mixtures, which described the homogenization of the mixture. On the other hand, mixtures were gelled by using aspersion of calcium chloride and characterized by dynamic rheology. Solid behavior is dominant in all range of frequency sweep test between 0.1Hz and 100Hz. Finally, the ultimate tensile strength of a gel reach 6.36938±0.24320kPa, which is enough for manual handling of the gel. Between the tasks of the gel would be used for cell entrapment, for controlled release of drugs or in the manufacture of wound dressings. PMID:24603213

  4. 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

  5. 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.

  6. Light-Directed Self-Assembly of Robust Alginate Gels at Precise Locations in Microfluidic Channels.

    PubMed

    Oh, Hyuntaek; Lu, Annie Xi; Javvaji, Vishal; DeVoe, Don L; Raghavan, Srinivasa R

    2016-07-13

    Recently there has been much interest in using light to activate self-assembly of molecules in a fluid, leading to gelation. The advantage of light over other stimuli lies in its spatial selectivity, i.e., its ability to be directed at a precise location, which could be particularly useful in microfluidic applications. However, existing light-responsive fluids are not suitable for these purposes since they do not convert into sufficiently strong gels that can withstand shear. Here, we address this deficiency by developing a new light-responsive system based on the well-known polysaccharide, alginate. The fluid is composed entirely of commercially available components: alginate, a photoacid generator (PAG), and a chelated complex of divalent strontium (Sr(2+)) cations. Upon exposure to ultraviolet (UV) light, the PAG dissociates to release H(+) ions, which in turn induce the release of free Sr(2+) from the chelate. The Sr(2+) ions self-assemble with the alginate chains to give a stiff gel with an elastic modulus ∼2000 Pa and a yield stress ∼400 Pa (this gel is strong enough to be picked up and held by one's fingers). The above fluid is sent through a network of microchannels and a short segment of a specific channel is exposed to UV light. At that point, the fluid is locally transformed into a strong gel in a few minutes, and the resulting gel blocks the flow through that channel while other channels remain open. When the UV light is removed, the gel is gradually diluted by the flow and the channel reopens. We have thus demonstrated a remote-controlled fluidic valve that can be closed by shining light and reopened when the light is removed. In addition, we also show that light-induced gelation of our alginate fluid can be used to deposit biocompatible payloads at specific addresses within a microchannel. PMID:27347595

  7. Preparation and characterization of physically modified glass beads used as model carriers in dry powder inhalers.

    PubMed

    Zellnitz, Sarah; Redlinger-Pohn, Jakob Dominik; Kappl, Michael; Schroettner, Hartmuth; Urbanetz, Nora Anne

    2013-04-15

    The aim of this work is the physical modification and characterization of the surface topography of glass beads used as model carriers in dry powder inhalers (DPIs). By surface modification the contact area between drug and carrier and thereby interparticle forces may be modified. Thus the performance of DPIs that relies on interparticle interactions may be improved. Glass beads were chosen as model carriers because various prospects of physical surface modification may be applied without affecting other factors also impacting interparticle interactions like particle size and shape. To generate rough surfaces glass beads were processed mechanically by friction and impaction in a ball mill with different grinding materials that were smaller and harder with respect to the glass beads. By varying the grinding time (4 h, 8 h) and by using different grinding media (tungsten carbide, quartz) surfaces with different shades of roughness were generated. Depending on the hardness of the grinding material and the grinding time the surface roughness was more or less pronounced. Surface roughness parameters and specific surface area were determined via several complementary techniques in order to get an enhanced understanding of the impact of the modifying procedure on the surface properties of the glass beads. PMID:23470233

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

    NASA Astrophysics Data System (ADS)

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

    2000-07-01

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

  9. 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

  10. 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. PMID:25660398

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

    PubMed

    Washington, N; Denton, G

    1995-11-01

    This randomized, single-blind cross-over study compared the effectiveness of a conventional alginate reflux barrier formulation (20 mL single dose of Liquid Gaviscon; sodium alginate, sodium bicarbonate, calcium carbonate) with a 20 mL single dose of an alginate-cimetidine combination formulation (Algitec Suspension; sodium alginate, cimetidine) in the suppression of food and acid reflux into the oesophagus after a test meal in 12 healthy volunteers. Subjects were fasted overnight before the study. A pH electrode and gamma detector were accurately positioned 5 cm above the cardia. The volunteers received a 99mTc-labelled meal designed to provoke reflux and then either remained untreated, or 30 min later were given either Algitec Suspension or Liquid Gaviscon. Reflux of both food and acid into the oesophagus was measured for 3 h. There was a seven day wash-out period between each treatment. Food reflux in the control group was 22,878 +/- 14,385 counts x 10(3) and this was significantly suppressed by both Liquid Gaviscon (174 +/- 128 (s.e.) counts x 10(3); P = 0.003); however, although the reduction of food reflux to 3812 +/- 2322 counts x 10(3) observed after Algitec treatment was considerable, this did not reach statistical significance (P > 0.05) due to the large intersubject variation. Liquid Gaviscon was significantly better at reducing food reflux than Algitec (P = 0.001). Gaviscon also significantly reduced acid reflux when compared with the control group (1.08 +/- 0.73 vs 5.87 +/- 3.27% recording time oesophageal pH < 4, respectively) (P = 0.03). The slight reduction in acid reflux after Algitec treatment (3.25 +/- 1.82% recording time oesophageal pH < 4) also did not reach statistical significance. The difference between Algitec and Gaviscon treatment was also not significant. PMID:8708979

  12. Cutting Tool For Shaving Weld Beads

    NASA Technical Reports Server (NTRS)

    Hoffman, David S.; Mcferrin, David C.; Daniel, Ronald L., Jr.; Coby, John B., Jr.; Dawson, Sidney G.

    1995-01-01

    Cutting tool proposed for use in shaving weld beads flush with adjacent surfaces of weldments. Modified version of commercial pneumatically driven rotary cutting tool, cutting wheel of which turns at speeds sufficient for machining nickel alloys, titanium, and stainless steels. Equipped with forward-mounted handle and rear-mounted skid plate to maximize control and reduce dependence on skill of technician.

  13. Glass-Bead Blasting Alters Antenna Surface

    NASA Technical Reports Server (NTRS)

    Fortenberry, James W.; Jilka, Richard L.; Kimmel, Boyce; Garcia, Ramon D.; Cofield, Richard E.; Klose, Gerhardt J.; O'Toole, Thomas

    1987-01-01

    Thermal-emissivity properties improved, and focal length adjusted. Experiments show gentle blasting with glass beads produces beneficial changes in macroscopic surface shapes and in microscopic surface features of lightweight microwave reflectors made of thin metal reflective surfaces on deformable substrates of aluminum honeycomb.

  14. Efficacy and reusability of alginate-immobilized live and heat-inactivated Trichoderma asperellum cells for Cu (II) removal from aqueous solution.

    PubMed

    Tan, Wei Shang; Ting, Adeline Su Yien

    2012-11-01

    Cu(II) removal efficacies of alginate-immobilized Trichoderma asperellum using viable and non-viable forms were investigated with respect to time, pH, and initial Cu(II) concentrations. The reusability potential of the biomass was determined based on sorption/desorption tests. Cu(II) biosorption by immobilized heat-inactivated T. asperellum cells was the most efficient, with 134.22mg Cu(II) removed g(-1) adsorbent, compared to immobilized viable cells and plain alginate beads (control) with 105.96 and 94.04mg Cu(II) adsorbed g(-1) adsorbent, respectively. Immobilized non-viable cells achieved equilibrium more rapidly within 4h. For all biosorbents, optimum pH for Cu(II) removal was between pH 4 and 5. Reusability of all biosorbents were similar, with more than 90% Cu(II) desorbed with HCl. These alginate-immobilized cells can be applied to reduce clogging and post-separation process incurred from use of suspended biomass. PMID:22940332

  15. Ethanol fermentation of sugarcane molasses by Zymomonas mobilis MTCC 92 immobilized in Luffa cylindrica L. sponge discs and Ca-alginate matrices.

    PubMed

    Behera, Shuvashish; Mohanty, Rama C; Ray, Ramesh C

    2012-10-01

    Bio-ethanol production from cane molasses (diluted to 15 % sugar w/v) was studied using the bacterium, Zymomonas mobilis MTCC 92 entrapped in luffa (Luffa cylindrica L.) sponge discs and Ca-alginate gel beads as the immobilizing matrices. At the end of 96 h fermentation, the final ethanol concentrations were 58.7 ± 0.09 and 59.1 ± 0.08 g/l molasses with luffa and Ca-alginate entrapped Z. mobilis cells, respectively exhibiting 83.25 ± 0.03 and 84.6 ± 0.02 % sugar conversion. There was no statistical significant difference (Fischer's LSD) in sugar utilization (t = 0.254, p<0.801) and ethanol production (t =-0.663, p<0.513) between the two immobilization matrices used. Further, the immobilized cells in both the matrices were physiologically active for three more cycles of operation with less than 15 % decrease in ethanol yield in the 4(th) cycle, which was due to some leakage of cells. In conclusion, luffa sponge was found to be equally good as Ca-alginate as a carrier material for bacterial (Z. mobilis) cell immobilization for ethanol production. Further, it has added advantages such as it is cheap, non-corrosive and has no environmental hazard. PMID:24031981

  16. Ethanol fermentation of sugarcane molasses by Zymomonas mobilis MTCC 92 immobilized in Luffa cylindrica L. sponge discs and Ca-alginate matrices

    PubMed Central

    Behera, Shuvashish; Mohanty, Rama C.; Ray, Ramesh C.

    2012-01-01

    Bio-ethanol production from cane molasses (diluted to 15 % sugar w/v) was studied using the bacterium, Zymomonas mobilis MTCC 92 entrapped in luffa (Luffa cylindrica L.) sponge discs and Ca-alginate gel beads as the immobilizing matrices. At the end of 96 h fermentation, the final ethanol concentrations were 58.7 ± 0.09 and 59.1 ± 0.08 g/l molasses with luffa and Ca-alginate entrapped Z. mobilis cells, respectively exhibiting 83.25 ± 0.03 and 84.6 ± 0.02 % sugar conversion. There was no statistical significant difference (Fischer’s LSD) in sugar utilization (t = 0.254, p<0.801) and ethanol production (t =-0.663, p<0.513) between the two immobilization matrices used. Further, the immobilized cells in both the matrices were physiologically active for three more cycles of operation with less than 15 % decrease in ethanol yield in the 4th cycle, which was due to some leakage of cells. In conclusion, luffa sponge was found to be equally good as Ca-alginate as a carrier material for bacterial (Z. mobilis) cell immobilization for ethanol production. Further, it has added advantages such as it is cheap, non-corrosive and has no environmental hazard. PMID:24031981

  17. Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism.

    PubMed

    Higham, Alina K; Bonino, Christopher A; Raghavan, Srinivasa R; Khan, Saad A

    2014-07-21

    We examine the gelation of alginate undergoing ionic crosslinking upon ultraviolet (UV) irradiation using in situ dynamic rheology. Hydrogels are formed by combining alginate with calcium carbonate (CaCO3) particles and a photoacid generator (PAG). The PAG is photolyzed upon UV irradiation, resulting in the release of free calcium ions for ionic crosslinking. The viscous and elastic moduli during gelation are monitored as a function of the UV irradiation intensity, exposure time, alginate concentration, and the ratio between alginate and calcium carbonate. Gel time decreases as irradiation intensity increases because a larger concentration of PAG is photolyzed. Interestingly, dark curing, the continuing growth of microstructure in the absence of UV light, is observed. In some instances, the sample transitions from a solution to a gel during the dark curing phase. Additionally, when exposed to constant UV irradiation after the dark curing phase, samples reach the same plateau modulus as samples exposed to constant UV without dark curing, implying that dark curing does not affect the gelation mechanism. We believe the presence of dark curing is the result of the acidic environment persisting within the sample, allowing CaCO3 to dissociate, thereby releasing free Ca(2+) ions capable of binding with the available appropriate ionic blocks of the polymer chains. The growth of microstructure is then detected if the activation barrier has been crossed to release sufficient calcium ions. In this regard, we calculate a value of 30 J that represents the activation energy required to initiate gelation. PMID:24894636

  18. Fabrication and characterization of novel nano-biocomposite scaffold of chitosan-gelatin-alginate-hydroxyapatite for bone tissue engineering.

    PubMed

    Sharma, Chhavi; Dinda, Amit Kumar; Potdar, Pravin D; Chou, Chia-Fu; Mishra, Narayan Chandra

    2016-07-01

    A novel nano-biocomposite scaffold was fabricated in bead form by applying simple foaming method, using a combination of natural polymers-chitosan, gelatin, alginate and a bioceramic-nano-hydroxyapatite (nHAp). This approach of combining nHAp with natural polymers to fabricate the composite scaffold, can provide good mechanical strength and biological property mimicking natural bone. Environmental scanning electron microscopy (ESEM) images of the nano-biocomposite scaffold revealed the presence of interconnected pores, mostly spread over the whole surface of the scaffold. The nHAp particulates have covered the surface of the composite matrix and made the surface of the scaffold rougher. The scaffold has a porosity of 82% with a mean pore size of 112±19.0μm. Swelling and degradation studies of the scaffold showed that the scaffold possesses excellent properties of hydrophilicity and biodegradability. Short term mechanical testing of the scaffold does not reveal any rupturing after agitation under physiological conditions, which is an indicative of good mechanical stability of the scaffold. In vitro cell culture studies by seeding osteoblast cells over the composite scaffold showed good cell viability, proliferation rate, adhesion and maintenance of osteoblastic phenotype as indicated by MTT assay, ESEM of cell-scaffold construct, histological staining and gene expression studies, respectively. Thus, it could be stated that the nano-biocomposite scaffold of chitosan-gelatin-alginate-nHAp has the paramount importance for applications in bone tissue-engineering in future regenerative therapies. PMID:27127072

  19. 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.

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

    PubMed Central

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

    2016-01-01

    Alginate is a hydrogel commonly used for cell culture by ionically crosslinking in the presence of divalent Ca2+ ions. However these alginate gels are mechanically unstable, not permitting their use as scaffolds to engineer robust biological bone, breast, cardiac or tumor tissues. This issue can be addressed via encapsulation of multi-walled carbon nanotubes (MWCNT) serving as a reinforcing phase while being dispersed in a continuous phase of alginate. We hypothesized that adding functionalized MWCNT to alginate, would yield composite gels with distinctively different mechanical, physical and biological characteristics in comparison to alginate alone. Resultant MWCNT-alginate gels were porous, and showed significantly less degradation after 14 days compared to alginate alone. In vitro cell-studies showed enhanced HeLa cell adhesion and proliferation on the MWCNT-alginate compared to alginate. The extent of cell proliferation was greater when cultured atop 1 and 3 mg/ml MWCNT-alginate; although all MWCNT-alginates lead to enhanced cell cluster formation compared to alginate alone. Among all the MWCNT-alginates, the 1 mg/ml gels showed significantly greater stiffness compared to all other cases. These results provide an important basis for the development of the MWCNT-alginates as novel substrates for cell culture applications, cell therapy and tissue engineering. PMID:27578567

  1. Mechanical and microstructural properties of "wet" alginate and composite films containing various carbohydrates.

    PubMed

    Harper, B Allison; Barbut, Shai; Smith, Alexandra; Marcone, Massimo F

    2015-01-01

    Composite "wet" alginate films were manufactured from alginate-carbohydrate solutions containing 5% alginate and 0.25% pectin, carrageenan (kappa or iota), potato starch (modified or unmodified), gellan gum, or cellulose (extracted or commercial). The "wet" alginate films were used as a model to understand co-extruded alginate sausage casings that are currently being used by several sausage manufacturers. The mechanical, optical, and microstructural properties of the calcium cross-linked composite films were explored. In addition, the water holding capacity and textural profile analysis properties of the alginate-carbohydrate gels were studied. The results indicate that the mechanical properties of "wet" alginate films/casings can be modified by adding various carbohydrates to them. Alginate films with pectin, carrageenan, and modified potato starch had significantly (P < 0.05) greater elongation values than pure alginate films. The alginate-pectin films also had greater (P < 0.05) tensile strengths than the pure alginate films. Alginate films with extracted cellulose, commercial cellulose, and modified potato starch had lower (P < 0.05) puncture force, distance, and work values than the alginate control films. Transmission electron microscopy images showed a very uniform alginate network in the control films. Several large cellulose fibers were visible in the films with extracted cellulose, while the cellulose fibers in the films with commercial cellulose were difficult to distinguish. Despite these apparent differences in cellulose fiber length, the 2 cellulose films had similar puncture and tensile properties. PMID:25471730

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

    PubMed

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

    2016-01-01

    Alginate is a hydrogel commonly used for cell culture by ionically crosslinking in the presence of divalent Ca(2+) ions. However these alginate gels are mechanically unstable, not permitting their use as scaffolds to engineer robust biological bone, breast, cardiac or tumor tissues. This issue can be addressed via encapsulation of multi-walled carbon nanotubes (MWCNT) serving as a reinforcing phase while being dispersed in a continuous phase of alginate. We hypothesized that adding functionalized MWCNT to alginate, would yield composite gels with distinctively different mechanical, physical and biological characteristics in comparison to alginate alone. Resultant MWCNT-alginate gels were porous, and showed significantly less degradation after 14 days compared to alginate alone. In vitro cell-studies showed enhanced HeLa cell adhesion and proliferation on the MWCNT-alginate compared to alginate. The extent of cell proliferation was greater when cultured atop 1 and 3 mg/ml MWCNT-alginate; although all MWCNT-alginates lead to enhanced cell cluster formation compared to alginate alone. Among all the MWCNT-alginates, the 1 mg/ml gels showed significantly greater stiffness compared to all other cases. These results provide an important basis for the development of the MWCNT-alginates as novel substrates for cell culture applications, cell therapy and tissue engineering. PMID:27578567

  3. The Alginate Demonstration: Polymers, Food Science, and Ion Exchange

    NASA Astrophysics Data System (ADS)

    Waldman, Amy Sue; Schechinger, Linda; Govindarajoo, Geeta; Nowick, James S.; Pignolet, Louis H.

    1998-11-01

    We have recently devised a polymer demonstration involving the crosslinking and decrosslinking of alginate, a polysaccharide isolated from seaweed. The polymer is composed of D-mannuronic acid and L-guluronic acid subunits and is a component of cell walls. It is commonly used as a thickener in foods such as ice cream and fruit-filled snacks. For the demonstration, a 2% solution of sodium alginate is poured into a 1% solution of calcium chloride. Nontoxic calcium alginate "worms" form due to crosslinking of the polymer. Alternatively, the commercially available antacid Gaviscon can be used as a source of sodium alginate. The crosslinks can then be broken by shaking the worms in brine. The demonstration is a fine addition to any chemical educator's repertoire of polymer experiments.

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

    PubMed

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

    2014-12-01

    Alginate oligosaccharides (AOs) prepared from alginate, by alginate lyase-mediated depolymerization, were structurally characterized by mass spectrometry, infrared spectrometry and thin layer chromatography. Studies of their antioxidant activities revealed that AOs were able to completely (100%) inhibit lipid oxidation in emulsions, superiorly to ascorbic acid (89% inhibition). AOs showed radical scavenging activity towards ABTṠ, hydroxyl, and superoxide radicals, which might explain their excellent antioxidant activity. The radical scavenging activity is suggested to originate mainly from the presence of the conjugated alkene acid structure formed during enzymatic depolymerization. According to the resonance hybrid theory, the parent radicals of AOs are delocalized through allylic rearrangement, and as a consequence, the reactive intermediates are stabilized. AOs were weak ferrous ion chelators. This work demonstrated that AOs obtained from a facile enzymatic treatment of abundant alginate is an excellent natural antioxidant, which may find applications in the food industry. PMID:24996323

  5. An appropriate selection of a 3D alginate culture model for hepatic Huh-7 cell line encapsulation intended for viral studies.

    PubMed

    Tran, Nhu Mai; Dufresne, Murielle; Duverlie, Gilles; Castelain, Sandrine; Défarge, Christian; Paullier, Patrick; Legallais, Cecile

    2013-01-01

    Three-dimensional (3D) culture systems have been introduced to provide cells with a biomimetic environment that is similar to in vivo conditions. Among the polymeric molecules available, sodium-alginate (Na-alg) salt is a material that is currently employed in different areas of drug delivery and tissue engineering, because it offers biocompatibility and optimal chemical properties, and its gelation with calcium chloride provides calcium-alginate (Ca-alg) scaffolds with mechanical stability and relative permeability. In this work, four different preparations of Ca-alg beads with varying Na-alg viscosity and concentration were used for a human hepatoma cell line (Huh-7) encapsulation. The effects of Ca-alg bead preparation on structural cell organization, liver-specific functions, and the expression of specific receptors implicated in hepatotropic virus permissivity were evaluated. Hepatic cells were cultured in 500 μm diameter Ca-alg beads for 7 days under dynamic conditions. For all culture systems, cell viability reached almost 100% at day 7. Cell proliferation was concomitantly followed by hepatocyte organization in aggregates, which adopted two different morphologies (spheroid aggregates or multicellular channel-like structures), depending on Ca-alg bead preparation. These cellular organizations established a real 3D hepatocyte architecture with cell polarity, cell junctions, and abundant bile canaliculi possessing microvillus-lined channels. The functionality of these 3D cultures was confirmed by the production of albumin and the exhibition of CYP1A activity over culture time, which were variable, according to Ca-alg bead condition. The expression of specific receptors of hepatitis C virus by Huh-7 cells suggests encouraging data for the further development of a new viral culture system in Ca-alg beads. In summary, this 3D hepatic cell culture represents a promising physiologically relevant system for further in vitro studies and demonstrates that an

  6. Motion of beads in an oscillatory rotating fluid: micro-bead-beating

    NASA Astrophysics Data System (ADS)

    Nadim, Ali; Sterling, James; Doebler, Robert

    2008-11-01

    One method for mechanical lysis of biological cells and spores is to mix them with a suspension of beads and vigorously ``shake'' the mixture. The precise mechanisms of lysis are not understood but lysis is thought to result from collisions between the beads and the cells and the associated stresses exerted on the cells. For instance, in the micro-bead-beater^TM instrument from Claremont BioSolutions LLC (Upland, CA), the ``shaking'' occurs when a small cartridge filled with a mixture of cells/spores and 100-micron beads is driven at high frequencies in a small arc trajectory. In this presentation, we describe our initial modeling effort aimed at understanding this system via analysis of the trajectories of beads within such an instrument. The equations governing the motion of non-neutrally-buoyant spherical beads in an oscillatory rotating flow are derived and analyzed numerically. The resulting trajectories are found to be quite complex and very different from those in a steadily rotating fluid. A catalog of possible trajectories at various values of the governing dimensionless parameters is presented.

  7. On-bead antibody-small molecule conjugation using high-capacity magnetic beads.

    PubMed

    Nath, Nidhi; Godat, Becky; Benink, Hélène; Urh, Marjeta

    2015-11-01

    Antibodies labeled with small molecules such as fluorophore, biotin or drugs play an important role in various areas of biological research, drug discovery and diagnostics. However, the majority of current methods for labeling antibodies is solution-based and has several limitations including the need for purified antibodies at high concentrations and multiple buffer exchange steps. In this study, a method (on-bead conjugation) is described that addresses these limitations by combining antibody purification and conjugation in a single workflow. This method uses high capacity-magnetic Protein A or Protein G beads to capture antibodies directly from cell media followed by conjugation with small molecules and elution of conjugated antibodies from the beads. High-capacity magnetic antibody capture beads are key to this method and were developed by combining porous and hydrophilic cellulose beads with oriented immobilization of Protein A and Protein G using HaloTag technology. With a variety of fluorophores it is shown that the on-bead conjugation method is compatible with both thiol- and amine-based chemistry. This method enables simple and rapid processing of multiple samples in parallel with high-efficiency antibody recovery. It is further shown that recovered antibodies are functional and compatible with downstream applications. PMID:26316179

  8. Retention and release behavior of insulin in chitosan gel beads.

    PubMed

    Kofuji, Kyoko; Akamine, Hiroyuki; Oshirabe, Hitomi; Maeda, Yasuyo; Murata, Yoshifumi; Kawashima, Susumu

    2003-01-01

    Chitosan (CS) gel beads were prepared in a 10% (w/v) aqueous amino acid solution (pH 9.0) as a vehicle for delivering peptide and protein drugs. CS gel beads with a weight-average molecular weight of (16-280) x 10(4) were employed in this study. Preparation of the CS gel beads was affected by properties such as molecular weight and degree of deacetylation. Insulin, which is commonly used to assess protein drug delivery, was retained in the CS gel beads. Drug release from the CS gel beads was governed by diffusion of drug from the gel matrix. Sustained release of insulin from the CS gel beads was observed, despite the fact that insulin is a comparatively water-soluble drug. because insulin formed a complex with CS. Modification of the CS gel matrix by chondroitin sulfate inhibited release of insulin from the gel beads. CS gel beads were implanted into air pouches prepared subcutaneously on the dorsal surface of diabetic mice in order to investigate the efficacy of insulin retained in the CS beads. Blood glucose levels were found to be reduced after implantation of CS gel beads retaining insulin. CS gel beads may possibly improve the stability and control of insulin release. These observations indicate that CS beads are a promising biocompatible and biodegradable vehicle for peptide and protein delivery. PMID:14768911

  9. Noncommercial fabrication of antibiotic-impregnated polymethylmethacrylate beads. Technical note.

    PubMed

    Flick, A B; Herbert, J C; Goodell, J; Kristiansen, T

    1987-10-01

    Antibiotic-impregnated polymethylmethacrylate (PMMA) beads were fabricated by means of injections in specially designed molds to produce small and large beads. In vitro concentrates from these beads for 30 days were found to release tobramycin in an exponential function. PMID:3652588

  10. 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

  11. Modulation of immunity and gut microbiota after dietary administration of alginate encapsulated Shewanella putrefaciens Pdp11 to gilthead seabream (Sparus aurata L.).

    PubMed

    Cordero, Héctor; Guardiola, Francisco A; Tapia-Paniagua, Silvana Teresa; Cuesta, Alberto; Meseguer, José; Balebona, M Carmen; Moriñigo, M Ángel; Esteban, M Ángeles

    2015-08-01

    The potential benefits of probiotics when administering to fish could improve aquaculture production. The objective of this study was to examine the modulation of immune status and gut microbiota of gilthead seabream (Sparus aurata L.) specimens by a probiotic when administered encapsulated. Commercial diet was enriched with Shewanella putrefaciens Pdp11 (SpPdp11, at a concentration of 10(8) cfu g(-1)) before being encapsulated in calcium alginate beads. Fish were fed non-supplemented (control) or supplemented diet for 4 weeks. After 1, 2 and 4 weeks the main humoral and cellular immune parameters were determined. Furthermore, gene expression profile of five immune relevant genes (il1β, bd, mhcIIα, ighm and tcrβ) was studied by qPCR in head kidney. On the other hand, intestinal microbiota of fish was analysed at 7 and 30 days by DGGE. Results demonstrated that administration of alginate encapsulated SpPdp11 has immunostimulant properties on humoral parameters (IgM level and serum peroxidase activity). Although no immunostimulant effects were detected on leucocyte activities, significant increases were detected in the level of mRNA of head-kidney leucocytes for mhcIIα and tcrβ after 4 weeks of feeding the encapsulated-probiotic diet. The administration of SpPdp11 encapsulated in alginate beads produced important changes in the DGGE patterns corresponding to the intestinal microbiota. Predominant bands related to lactic acid bacteria, such as Lactococcus and Lactobacillus strains, were sequenced from the DGGE patterns of fish fed the probiotic diet, whereas they were not sequenced from fish receiving the control diet. The convenience or not of probiotic encapsulation is discussed. PMID:26003737

  12. Boost for Alginate Encapsulation in Beta Cell Transplantation.

    PubMed

    Pipeleers, Daniel; Keymeulen, Bart

    2016-05-01

    A recent study reported that encapsulation of human embryonic stem cell (hESC)-derived beta cells by a novel alginate formula protects against foreign body reactivity in immune-competent mice. Intraperitoneal implants corrected a diabetic state for at least 6 months. These observations will stimulate the development of alginate encapsulation towards novel cell therapy protocols for treating type 1 diabetes (T1DM). PMID:27037212

  13. Nanocellulose-alginate hydrogel for cell encapsulation.

    PubMed

    Park, Minsung; Lee, Dajung; Hyun, Jinho

    2015-02-13

    TEMPO-oxidized bacterial cellulose (TOBC)-sodium alginate (SA) composites were prepared to improve the properties of hydrogel for cell encapsulation. TOBC fibers were obtained using a TEMPO/NaBr/NaClO system at pH 10 and room temperature. The fibrillated TOBCs mixed with SA were cross-linked in the presence of Ca(2+) solution to form hydrogel composites. The compression strength and chemical stability of the TOBC/SA composites were increased compared with the SA hydrogel, which indicated that TOBC performed an important function in enhancing the structural, mechanical and chemical stability of the composites. Cells were successfully encapsulated in the TOBC/SA composites, and the viability of cells was investigated. TOBC/SA composites can be a potential candidate for cell encapsulation engineering. PMID:25458293

  14. 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

  15. 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. PMID:25693065

  16. Sodium alginate decreases the permeability of intestinal mucus

    PubMed Central

    Mackie, Alan R.; Macierzanka, Adam; Aarak, Kristi; Rigby, Neil M.; Parker, Roger; Channell, Guy A.; Harding, Stephen E.; Bajka, Balazs H.

    2016-01-01

    In the small intestine the nature of the environment leads to a highly heterogeneous mucus layer primarily composed of the MUC2 mucin. We set out to investigate whether the soluble dietary fibre sodium alginate could alter the permeability of the mucus layer. The alginate was shown to freely diffuse into the mucus and to have minimal effect on the bulk rheology when added at concentrations below 0.1%. Despite this lack of interaction between the mucin and alginate, the addition of alginate had a marked effect on the diffusion of 500 nm probe particles, which decreased as a function of increasing alginate concentration. Finally, we passed a protein stabilised emulsion through a simulation of oral, gastric and small intestinal digestion. We subsequently showed that the addition of 0.1% alginate to porcine intestinal mucus decreased the diffusion of fluorescently labelled lipid present in the emulsion digesta. This reduction may be sufficient to reduce problems associated with high rates of lipid absorption such as hyperlipidaemia. PMID:26726279

  17. Polymeric alginate nanoparticles containing the local anesthetic bupivacaine.

    PubMed

    Grillo, Renato; de Melo, Nathalie F S; de Araújo, Daniele Ribeiro; de Paula, Eneida; Rosa, André Henrique; Fraceto, Leonardo Fernandes

    2010-11-01

    Bupivacaine (BVC; S75–R25, NovaBupi® is an amide-type local anesthetic. Sodium alginate is a water-soluble linear polysaccharide. The present study reports the development of alginate/bis(2-ethylhexyl) sulfosuccinate (AOT) and alginate/chitosan nanoparticle formulations containing BVC (0.5%). The amounts of BVC associated in the alginate/AOT and alginate/chitosan nanoparticles were 87 ± 1.5 and 76 ± 0.9%, respectively. The average diameters and zeta potentials of the nanoparticles were measured for 30 days, and the results demonstrated the good stability of these particles in solution. The in vitro release kinetics showed a different behavior for the release profile of BVC in solution, compared with BVC-loaded alginate nanoparticles. In vitro and in vivo assays showed that alginate–chitosan BVC (BVC(ALG–CHIT)) and alginate–AOT BVC (BVC(ALG–AOT)) presented low cytotoxicity in 3T3-fibroblasts, enhanced the intensity, and prolonged the duration of motor and sensory blockades in a sciatic nerve blockade model. PMID:20196632

  18. Optical vortex beam transmission with different OAM in scattering beads and brain tissue media

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Shi, Lingyan; Lindwasser, Lukas; Marque, Paulo; Lavery, M. P. J.; Alfano, R. R.

    2016-03-01

    Light transmission of Laguerre Gaussian (LG) vortex beams with different orbital angular momentum (OAM) values (L) in scattering beads and mouse brain tissue media were experimentally investigated for the first time in comparison with Gaussian (G) beams. The LG beams with different OAM were generated using a spatial light modulator (SLM) in reflection mode. The scattering beads media consist of various sizes and concentrations of latex beads in water solutions. The transmissions of LG and G beams through scattering beads and brain tissue media were measured with different ratios of sample thicknesses (z) to scattering mean free path (ls) of the turbid media, z/ls. The results indicate that within the ballistic region where z/ls is small, the LG and G beams show no significant difference, while in the diffusive region where z/ls is higher, the vortex beams show higher transmission than G beams. In the diffusive region, the LG beams with higher L values show higher transmission than the beams with lower L values due to the eigen channels in the media. The transition points from the ballistic to diffusive regions for different scattering beads and brain tissue media were studied.

  19. Experimental analysis of nanofluid pool boiling heat transfer in copper bead packed porous layers

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Wang, Ji

    2016-07-01

    Coupling the nanofluid as working fluid and the copper beads packed porous structure on heating surface were employed to enhance the pool boiling heat transfer by changing the fluid properties with the adjunction of nanoparticles in liquid and altering the heating surface with a bead porous layer. Due to the higher thermal conductivity, the copper beads served as an extended heating surface and the boiling nucleation sites rose, but the flow resistance increased. The CuO-water and SiO2-water nanofluids as well as the pure water were respectively employed as working fluids in the pool boiling experiments. Comparing with the base fluid of water, the higher thermal conductivity and lower surface tension occur in the nanofluids and those favor the boiling heat transfer, but the higher viscosity and density of nanofluids serve as deteriorative factors. So, the concentration region of the nanofluids should be chosen properly. The maximum relative error between the collected experimental data of the pure water on a flat surface and the theoretical prediction of pool boiling using the Rohsenow correlation was less than 12 %. The comparisons of the pool boiling heat transfer characteristics were also conducted between the pure water and the nanofluids respectively on the horizontal flat surface and on the heating surface packed with a copper bead porous layer. Besides, the boiling bubble generation, integration and departure have a great affect on the pool boiling and were recorded with a camera in the bead stacked porous structures at different heat flux.

  20. A Pseudomonas aeruginosa alginate-exotoxin A conjugate that elicits anti-alginate and exotoxin A-neutralizing antibodies.

    PubMed

    Coin, D; Vacheron, M J; Guinand, M; Michel, G

    1991-08-01

    Pseudomonas aeruginosa alginate was covalently coupled to exotoxin A by reductive amination using adipic acid dihydrazide as spacer. The conjugate was composed of 25% alginate and 75% exotoxin A and possessed an average molecular mass higher than 700 kDa as determined by polyacrylamide gel electrophoresis. The conjugate had virtually no ADP-ribosyltransferase activity and a reduced cytotoxicity for TSA8 murine cells, derived from Friend erythroleukemia cells, as indicated by a greater than 50-fold increased LD50. Anti-conjugate antibodies recognized exotoxin A and alginate. A booster injection resulted in markedly increased antibody ELISA titers to both exotoxin A and alginate. The antibodies neutralized the exotoxin A toxicity. PMID:1931130

  1. Complete sucrose hydrolysis by heat-killed recombinant Pichia pastoris cells entrapped in calcium alginate

    PubMed Central

    2014-01-01

    Background An ideal immobilized biocatalyst for the industrial-scale production of invert sugar should stably operate at elevated temperatures (60-70°C) and high sucrose concentrations (above 60%, w/v). Commercial invertase from the yeast Saccharomyces cerevisiae is thermolabile and suffers from substrate inhibition. Thermotoga maritima β-fructosidase (BfrA) is the most thermoactive and thermostable sucrose-hydrolysing enzyme so far identified and allows complete inversion of the substrate in highly concentrated solutions. Results In this study, heat-killed Pichia pastoris cells bearing N-glycosylated BfrA in the periplasmic space were entrapped in calcium alginate beads. The immobilized recombinant yeast showed maximal sucrose hydrolysis at pH 5–7 and 90°C. BfrA was 65% active at 60°C and had no activity loss after incubation without the substrate at this temperature for 15 h. Complete inversion of cane sugar (2.04 M) at 60°C was achieved in batchwise and continuous operation with respective productivities of 4.37 and 0.88 gram of substrate hydrolysed per gram of dry beads per hour. The half-life values of the biocatalyst were 14 and 20 days when operated at 60°C in the stirred tank and the fixed-bed column, respectively. The reaction with non-viable cells prevented the occurrence of sucrose fermentation and the formation of by-products. Six-month storage of the biocatalyst in 1.46 M sucrose (pH 5.5) at 4°C caused no reduction of the invertase activity. Conclusions The features of the novel thermostable biocatalyst developed in this study are more attractive than those of immobilized S. cerevisiae cells for application in the enzymatic manufacture of inverted sugar syrup in batch and fixed-bed reactors. PMID:24943124

  2. Delivering MC3T3-E1 cells into injectable calcium phosphate cement through alginate-chitosan microcapsules for bone tissue engineering*

    PubMed Central

    Qiao, Peng-yan; Li, Fang-fang; Dong, Li-min; Xu, Tao; Xie, Qiu-fei

    2014-01-01

    Objective: To deliver cells deep into injectable calcium phosphate cement (CPC) through alginate-chitosan (AC) microcapsules and investigate the biological behavior of the cells released from microcapsules into the CPC. Methods: Mouse osteoblastic MC3T3-E1 cells were embedded in alginate and AC microcapsules using an electrostatic droplet generator. The two types of cell-encapsulating microcapsules were then mixed with a CPC paste. MC3T3-E1 cell viability was investigated using a Wst-8 kit, and osteogenic differentiation was demonstrated by an alkaline phosphatase (ALP) activity assay. Cell attachment in CPC was observed by an environment scanning electron microscopy. Results: Both alginate and AC microcapsules were able to release the encapsulated MC3T3-E1 cells when mixed with CPC paste. The released cells attached to the setting CPC scaffolds, survived, differentiated, and formed mineralized nodules. Cells grew in the pores concomitantly created by the AC microcapsules in situ within the CPC. At Day 21, cellular ALP activity in the AC group was approximately four times that at Day 7 and exceeded that of the alginate microcapsule group (P<0.05). Pores formed by the AC microcapsules had a diameter of several hundred microns and were spherical compared with those formed by alginate microcapsules. Conclusions: AC microcapsule is a promising carrier to release seeding cells deep into an injectable CPC scaffold for bone engineering. PMID:24711359

  3. Synthesis of magnetic resonance–, X-ray– and ultrasound-visible alginate microcapsules for immunoisolation and noninvasive imaging of cellular therapeutics

    PubMed Central

    Barnett, Brad P; Arepally, Aravind; Stuber, Matthias; Arifin, Dian R; Kraitchman, Dara L; Bulte, Jeff W M

    2011-01-01

    Cell therapy has the potential to treat or cure a wide variety of diseases. Non-invasive cell tracking techniques are, however, necessary to translate this approach to the clinical setting. This protocol details methods to create microcapsules that are visible by X-ray, ultrasound (US ) or magnetic resonance (MR) for the encapsulation and immunoisolation of cellular therapeutics. Three steps are generally used to encapsulate cellular therapeutics in an alginate matrix: (i) droplets of cell-containing liquid alginate are extruded, using an electrostatic generator, through a needle tip into a solution containing a dissolved divalent cation salt to form a solid gel; (ii) the resulting gelled spheres are coated with polycations as a cross-linker; and (iii) these complexes are then incubated in a second solution of alginate to form a semipermeable membrane composed of an inner and an outer layer of alginate. The microcapsules can be rendered visible during the first step by adding contrast agents to the primary alginate layer. Such contrast agents include superparamagnetic iron oxide for detection by 1H MR imaging (MRI); the radiopaque agents barium or bismuth sulfate for detection by X-ray modalities; or perfluorocarbon emulsions for multimodal detection by 19F MRI, X-ray and US imaging. The entire synthesis can be completed within 2 h. PMID:21799484

  4. Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

    USGS Publications Warehouse

    Arp, Christopher D.; Whitman, Matthew S.; Jones, Benjamin M.; Grosse, Guido; Gaglioti, Benjamin V.; Heim, Kurt C.

    2015-01-01

    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 survey 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- ground 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 a relatively stable landform 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 riparian zones effectively insulates channel 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 thermally stratify, 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, yet channel runs still move water rapidly

  5. Distribution and biophysical processes of beaded streams in 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.

    2015-01-01

    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 survey 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 ground-ice content permafrost in moderately sloping terrain. In one Arctic coastal plain 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. The comparisons of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform, 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 riparian zones, effectively insulate channel 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 that range from 0.7 to 1.6 m. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains cold-water 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 0.01 to 0.1 m s-1

  6. Green stone beads at the dawn of agriculture.

    PubMed

    Bar-Yosef Mayer, Daniella E; Porat, Naomi

    2008-06-24

    The use of beads and other personal ornaments is a trait of modern human behavior. During the Middle and Upper Paleolithic periods, beads were made out of shell, bone, ivory, egg shell, and occasionally of minerals. During the transition to agriculture in the Near East, stone, in particular green stone, was used for the first time to make beads and pendants. We observed that a large variety of minerals of green colors were sought, including apatite, several copper-bearing minerals, amazonite and serpentinite. There seems to be an increase with time of distance from which the green minerals were sought. Because beads in white, red, yellow, brown, and black colors had been used previously, we suggest that the occurrence of green beads is directly related to the onset of agriculture. Green beads and bead blanks were used as amulets to ward off the evil eye and as fertility charms. PMID:18559861

  7. Green stone beads at the dawn of agriculture

    PubMed Central

    Bar-Yosef Mayer, Daniella E.; Porat, Naomi

    2008-01-01

    The use of beads and other personal ornaments is a trait of modern human behavior. During the Middle and Upper Paleolithic periods, beads were made out of shell, bone, ivory, egg shell, and occasionally of minerals. During the transition to agriculture in the Near East, stone, in particular green stone, was used for the first time to make beads and pendants. We observed that a large variety of minerals of green colors were sought, including apatite, several copper-bearing minerals, amazonite and serpentinite. There seems to be an increase with time of distance from which the green minerals were sought. Because beads in white, red, yellow, brown, and black colors had been used previously, we suggest that the occurrence of green beads is directly related to the onset of agriculture. Green beads and bead blanks were used as amulets to ward off the evil eye and as fertility charms. PMID:18559861

  8. Discrete dipole approximation simulation of bead enhanced diffraction grating biosensor

    NASA Astrophysics Data System (ADS)

    Arif, Khalid Mahmood

    2016-08-01

    We present the discrete dipole approximation simulation of light scattering from bead enhanced diffraction biosensor and report the effect of bead material, number of beads forming the grating and spatial randomness on the diffraction intensities of 1st and 0th orders. The dipole models of gratings are formed by volume slicing and image processing while the spatial locations of the beads on the substrate surface are randomly computed using discrete probability distribution. The effect of beads reduction on far-field scattering of 632.8 nm incident field, from fully occupied gratings to very coarse gratings, is studied for various bead materials. Our findings give insight into many difficult or experimentally impossible aspects of this genre of biosensors and establish that bead enhanced grating may be used for rapid and precise detection of small amounts of biomolecules. The results of simulations also show excellent qualitative similarities with experimental observations.

  9. hνSABR: Photochemical Dose-Response Bead Screening in Droplets.

    PubMed

    Price, Alexander K; MacConnell, Andrew B; Paegel, Brian M

    2016-03-01

    With the potential for each droplet to act as a unique reaction vessel, droplet microfluidics is a powerful tool for high-throughput discovery. Any attempt at compound screening miniaturization must address the significant scaling inefficiencies associated with library handling and distribution. Eschewing microplate-based compound collections for one-bead-one-compound (OBOC) combinatorial libraries, we have developed hνSABR (Light-Induced and -Graduated High-Throughput Screening After Bead Release), a microfluidic architecture that integrates a suspension hopper for compound library bead introduction, droplet generation, microfabricated waveguides to deliver UV light to the droplet flow for photochemical compound dosing, incubation, and laser-induced fluorescence for assay readout. Avobenzone-doped PDMS (0.6% w/w) patterning confines UV exposure to the desired illumination region, generating intradroplet compound concentrations (>10 μM) that are reproducible between devices. Beads displaying photochemically cleavable pepstatin A were distributed into droplets and exposed with five different UV intensities to demonstrate dose-response screening in an HIV-1 protease activity assay. This microfluidic architecture introduces a new analytical approach for OBOC library screening, and represents a key component of a next-generation distributed small molecule discovery platform. PMID:26815064

  10. hνSABR: Photochemical Dose–Response Bead Screening in Droplets

    PubMed Central

    2016-01-01

    With the potential for each droplet to act as a unique reaction vessel, droplet microfluidics is a powerful tool for high-throughput discovery. Any attempt at compound screening miniaturization must address the significant scaling inefficiencies associated with library handling and distribution. Eschewing microplate-based compound collections for one-bead-one-compound (OBOC) combinatorial libraries, we have developed hνSABR (Light-Induced and -Graduated High-Throughput Screening After Bead Release), a microfluidic architecture that integrates a suspension hopper for compound library bead introduction, droplet generation, microfabricated waveguides to deliver UV light to the droplet flow for photochemical compound dosing, incubation, and laser-induced fluorescence for assay readout. Avobenzone-doped PDMS (0.6% w/w) patterning confines UV exposure to the desired illumination region, generating intradroplet compound concentrations (>10 μM) that are reproducible between devices. Beads displaying photochemically cleavable pepstatin A were distributed into droplets and exposed with five different UV intensities to demonstrate dose–response screening in an HIV-1 protease activity assay. This microfluidic architecture introduces a new analytical approach for OBOC library screening, and represents a key component of a next-generation distributed small molecule discovery platform. PMID:26815064

  11. Application of Pcvd Process to Uniform Coating of TiO2 Thin Films on Polypropylene Beads

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Joo; Pham, Hung Cuong; Kim, Kyo-Seon

    The growth of the TiO2 thin films coated on the polypropylene beads was analyzed experimentally in a rotating cylindrical plasma chemical vapor deposition (PCVD) reactor. The precursors for the thin films were generated by plasma reactions, and they deposited on the polypropylene beads to become the uniform thin films. The TiO2 thin films grow more quickly on the polypropylene beads by increasing the mass flow rate of TTIP, or the rotation speed of the reactor. The smaller number of polypropylene beads in the reactor increases the growth rate of the thin films. The high-quality TiO2 thin films can be coated on particles uniformly by using the rotating cylindrical PCVD process. The particles coated with high-quality TiO2 thin films can be applied to the removal of air and water pollutants by a photodegradation reaction of TiO2.

  12. Development of a bead-based suspension array for the detection of pathogens in acute respiratory tract infections.

    PubMed

    Chen, Yu-Sheng; Li, Hong-Ru; Zhang, Wei; Hua, Zhi-Dan; Lin, Xiao-Hong; Lin, Meng-Qing; Huang, Wen-Sen; Huang, Li-Ping; Yu, Xiao-Li; Xu, Neng-Luan; Lin, Ming; Xie, Bao-Song; Shen, Xiao-Na; Xie, Jian-Feng; Wang, Yi; Huang, Meng; Wu, Yan-An; Hu, Xin-Lan

    2016-08-01

    We developed a high-throughput bead-based suspension array for simultaneous detection of 20 respiratory tract pathogens in clinical specimens. Pathogen-specific genes were amplified and hybridized to probes coupled to carboxyl-encoded microspheres. Fluorescence intensities generated via the binding of phycoerythrin-conjugated streptavidin with biotin-labeled targets were measured by the Luminex 100 bead-based suspension array system. The bead-based suspension array detected bacteria in a significantly higher number of samples compared to the conventional culture. There was no significant difference in the detection rate of atypical pathogensatypical pathogens or viruses between the bead-based suspension array and real-time PCR. This technology can play a significant role in screening patients with pneumonia. PMID:27190247

  13. Ceramic Spheres From Cation Exchange Beads

    NASA Technical Reports Server (NTRS)

    Dynys, F. W.

    2003-01-01

    Porous ZrO2 and hollow TiO2 spheres were synthesized from a strong acid cation exchange resin. Spherical cation exchange beads, polystyrene based polymer, were used as a morphological-directing template. Aqueous ion exchange reaction was used to chemically bind (ZrO)(2+) ions to the polystyrene structure. The pyrolysis of the polystyrene at 600 C produces porous ZrO2 spheres with a surface area of 24 sq m/g with a mean sphere size of 42 microns. Hollow TiO2 spheres were synthesized by using the beads as a micro-reactor. A direct surface reaction - between titanium isopropoxide and the resin beads forms a hydrous TiO2 shell around the polystyrene core. The pyrolysis of the polystyrene core at 600 C produces hollow anatase spheres with a surface area of 42 sq m/g with a mean sphere size of 38 microns. The formation of ceramic spheres was studied by XRD, SEM and B.E.T. nitrogen adsorption measurements.

  14. Concepts for increasing gentamicin release from handmade bone cement beads

    PubMed Central

    2009-01-01

    Background and purpose Commercial gentamicin-loaded bone cement beads (Septopal) constitute an effective delivery system for local antibiotic therapy. These beads are not available in all parts of the world, and are too expensive for frequent use in others. Thus, orthopedic surgeons worldwide make antibiotic-loaded beads themselves. However, these beads are usually not as effective as the commercial beads because of inadequate release kinetics. Our purpose was to develop a simple, cheap, and effective formulation to prepare gentamicin-loaded beads with release properties and antibacterial efficacy similar to the commercially ones. Methods Acrylic beads were prepared with variable monomer content: 100% (500 μL/g polymer), 75%, and 50% to increase gentamicin release through creation of a less dense polymer matrix. Using the optimal monomer content, different gel-forming polymeric fillers were added to enhance the permeation of fluids into the beads. Polyvinylpyrrolidone (PVP) 17 was selected as a suitable filler; its concentration was varied and the antibiotic release and antibacterial efficacy of these beads were compared with the corresponding properties of the commercial ones. Results Gentamicin release rate and the extent of release from beads prepared with 50% monomer increased when the PVP17 content was increased. Beads with 15 w/w% PVP17 released 87% of their antibiotic content. This is substantially more than the gentamicin release from Septopal beads (59%). Acrylic beads with 15 w/w% PVP17 reduced bacterial growth by up to 93%, which is similar to the antibacterial properties of the commercial ones. Interpretation A simple, cheap, and effective formulation and preparation process has been described for hand-made gentamicin-releasing acrylic beads, with better release kinetics and with antibacterial efficacy similar to that of the commercial ones. PMID:19916680

  15. Alginate Polymerization and Modification Are Linked in Pseudomonas aeruginosa

    PubMed Central

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

    2015-01-01

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

  16. In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix.

    PubMed

    Sargus-Patino, Catherine N; Wright, Elane C; Plautz, Sarah A; Miles, Jeremy R; Vallet, Jeff L; Pannier, Angela K

    2014-08-01

    Between Days 10 and 12 of gestation, porcine embryos undergo a dramatic morphological change, known as elongation, with a corresponding increase in oestrogen production that triggers maternal recognition of pregnancy. Elongation deficiencies contribute to embryonic loss, but exact mechanisms of elongation are poorly understood due to the lack of an effective in vitro culture system. Our objective was to use alginate hydrogels as three-dimensional scaffolds that can mechanically support the in vitro development of preimplantation porcine embryos. White cross-bred gilts were bred at oestrus (Day 0) to Duroc boars and embryos were recovered on Days 9, 10 or 11 of gestation. Spherical embryos were randomly assigned to be encapsulated within double-layered 0.7% alginate beads or remain as non-encapsulated controls (ENC and CONT treatment groups, respectively) and were cultured for 96h. Every 24h, half the medium was replaced with fresh medium and an image of each embryo was recorded. At the termination of culture, embryo images were used to assess morphological changes and cell survival. 17β-Oestradiol levels were measured in the removed media by radioimmunoassay. Real-time polymerase chain reaction was used to analyse steroidogenic transcript expression at 96h in ENC and CONT embryos, as well as in vivo-developed control embryos (i.e. spherical, ovoid and tubular). Although no differences in cell survival were observed, 32% (P<0.001) of the surviving ENC embryos underwent morphological changes characterised by tubal formation with subsequent flattening, whereas none of the CONT embryos exhibited morphological changes. Expression of steroidogenic transcripts STAR, CYP11A1 and CYP19A1 was greater (P<0.07) in ENC embryos with morphological changes (ENC+) compared with CONT embryos and ENC embryos with no morphological changes (ENC-), and was more similar to expression of later-stage in vivo-developed controls. Furthermore, a time-dependent increase (P<0.001) in 17

  17. Improved protocol for somatic embryogenesis and calcium alginate encapsulation in Anethum graveolens L.: a medicinal herb.

    PubMed

    Dhir, Richa; Shekhawat, G S; Alam, Afroz

    2014-08-01

    An improved procedure has been developed for efficient somatic embryogenesis in Anethum graveolens. Green friable embryogenic callus was obtained from hypocotyl segments on medium augmented with 2,4-dichlorophenoxyacetic acid (2,4-D). The highest embryogenic callus induction frequency of 87 % was obtained on Murashige and Skoog (MS) medium containing 1.13 μM 2,4-D. At lower concentration of 2,4-D (0.34 μM) callus turned dark in color and slow growing. Embryogenic cultures (76 %) responded with a mean number of 43 globular and 18 heart stage embryos. Somatic embryo maturation and subsequent conversion into plantlets took place on MS lacking growth regulators. Maximum number of somatic embryos developed on MS medium was 128.3 (per flask) and a plantlet conversion of 82 % was observed. Calcium alginate beads were produced by encapsulating somatic embryos. Highest percent germination (83 %) was observed on 0.8 % agar solidified MS medium with the plantlets acquiring an average length of 2.1 cm. Encapsulated somatic embryos could be stored at 4 °C up to 60 days with a conversion frequency of 49.3 %. Highest protein and proline content has been observed in embryogenic callus with small globular embryos. During morphological differentiation of the somatic embryos, changes in the antioxidant enzymatic system were observed. Superoxide dismutase (SOD) activity increased during initial stages and decreased catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) activities were detected. PMID:24974170

  18. Uranium (VI) recovery from aqueous medium using novel floating macroporous alginate-agarose-magnetite cryobeads.

    PubMed

    Tripathi, Anuj; Melo, Jose Savio; D'Souza, Stanislaus Francis

    2013-02-15

    This study presents a novel development of a floating polymeric-magnetite cryobead for the recovery of hexavalent uranium from the aqueous sub-surfaces. The alginate-agarose-magnetite cryobeads were synthesized by the process of cryotropic-gelation at subzero-temperature. The physico-chemical properties of cryobeads showed high surface area and high interconnected porosity (≈ 90%). Low density of these cryobeads explains their floating property in the aqueous medium. The rheological analysis of cryobeads showed its stability and increased stiffness after uranium adsorption. The presence of magnetite nanoparticles in the porous cryobeads facilitates the recovery of these beads by applying an external magnetic field. Maximum uranium adsorption (97 ± 2%) was observed in the pH range of 4.5-5.5. The thermodynamic parameters suggest passive endothermic adsorption behaviour. HCl was found to be an efficient eluent for the uranium desorption. Five repeated cycles for the desorption of uranium from biosorbent showed 69 ± 3% of uranium recovery. These results suggest stability of these novel floating magnetite-cryobeads under environmental conditions with potential for the recovery of uranium from contaminated aqueous subsurfaces. PMID:23280054

  19. Ca-alginate hydrogel mechanical transformations--the influence on yeast cell growth dynamics.

    PubMed

    Pajić-Lijaković, Ivana; Plavsić, Milenko; Bugarski, Branko; Nedović, Viktor

    2007-05-01

    A mathematical model was formulated to describe yeast cell growth within the Ca-alginate microbead during air-lift bioreactor cultivation. Model development was based on experimentally obtained data for the intra-bead cell concentration profile, after reached the equilibrium state, as well as, total yeast cell concentration per microbed and microbead volume as function of time. Relatively uniform cell concentration in the carrier matrix indicated that no internal nutrient diffusion limitations, but microenvironmental restriction, affected dominantly the dynamics of cell growth. Also interesting phenomenon of very different rates of cell number growth during cultivation is observed. After some critical time, the growth rate of cell colonies decreased drastically, but than suddenly increased again under all other experimental condition been the same. It is interpreted as disintegration of gel network and opening new free space for growth of cell clusters. These complex phenomena are modeled using the thermodynamical, free energy formalism. The particular form of free energy functional is proposed to describe various kinds of interactions, which affected the dynamics of cell growth and cause pseudo-phase transition of hydrogel. The good agreement of experimentally obtained data and model predictions are obtained. In that way the model provides both, the quantitative tools for further technological optimization of the process and deeper insight into dynamics of cell growth mechanism. PMID:17331608

  20. Single-bead arrays for fluorescence-based immunoassays on capillary-driven microfluidic chips

    NASA Astrophysics Data System (ADS)

    Temiz, Yuksel; Lim, Michel; Delamarche, Emmanuel

    2016-03-01

    We report a concept for the simple fabrication of easy-to-use chips for immunoassays in the context of point-of-care diagnostics. The chip concept comprises mainly three features: (1) the efficient integration of reagents using beads functionalized with receptors, (2) the generation of capillary-driven liquid flows without using external pumps, and (3) a high-sensitivity detection of analytes using fluorescence microscopy. We fabricated prototype chips using dry etching of Si wafers. 4.5-μm-diameter beads were integrated into hexagonal arrays by sedimentation and removing the excess using a stream of water. We studied the effect of different parameters and showed that array occupancies from 30% to 50% can be achieved by pipetting a 250 nL droplet of 1% bead solution and allowing the beads sediment for 3 min. Chips with integrated beads were sealed using a 50-μm-thick dry-film resist laminated at 45 °C. Liquids pipetted to loading pads were autonomously pulled by capillary pumps at a rate of 0.35 nL s-1 for about 30 min. We studied ligand-receptor interactions and binding kinetics using time-lapse fluorescence microscopy and demonstrated a 5 pM limit of detection (LOD) for an anti-biotin immunoassay. As a clinically-relevant example, we implemented an immunoassay to detect prostate specific antigen (PSA) and showed an LOD of 108 fM (i.e. 3.6 pg mL-1). While a specific implementation is provided here for the detection of PSA, we believe that combining capillary-driven microfluidics with arrays of single beads and fluorescence readout to be very flexible and sufficiently sensitive for the detection of other clinically-relevant analytes.

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

    PubMed Central

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

    2014-01-01

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

  2. Development of a new technique using glass beads for dry dispersion of airborne fungal spores.

    PubMed

    Shimasaki, Noriko; Okaue, Akira; Kikuno, Ritsuko; Okuda, Shunji; Abe, Keiko

    2015-01-01

    To evaluate the removal of airborne microbes by air cleaners, a technique for generating airborne fungal spores in the dry state in a test chamber (dry dispersion) become necessary. The Society of Indoor Environment Japan (SIEJ) published SIEJ Standard Method No. 20110001 (SIEJ standard),in which an aerial ultrasonic oscillator was used as the device for dry dispersion. However, a more versatile apparatus is also necessary from a practical point of view. Therefore, we developed a new device using glass beads for the dispersion. Glass beads and a fungal sheet containing spores of Wallemia sebi were set in a midget impinger, which was connected to a compressor and a compact test chamber (1 m(3)). Air was blown into the impinger from the compressor. The spores on the fungal sheet were released by impingement of the glass beads when the beads were induced to float by the air blown into the impinger, and the spores were introduced to the chamber by the airflow. This newly developed technique can be used in a compact chamber system and could be applicable as an improved method for generating airborne fungal spores in the dry state in the SIEJ standard. PMID:25817813

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

    PubMed Central

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

    2014-01-01

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

  4. Towards antimicrobial yet bioactive Cu-alginate hydrogels.

    PubMed

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

    2016-01-01

    The simplest approach to enhance alginate hydrogel characteristics and functional properties is to replace the calcium in the process of alginate gelation with other metallic ions which are essential for living systems. Gelling of alginate with other ions and using modern encapsulation techniques can provide new delivery systems with required properties. Hence, in this study Cu-alginate hydrogels in the form of microbeads were produced by electrostatic extrusion using gelling solutions with Cu(II) concentrations in the range 13.5-270 mM and comprehensively characterized in vitro. The variation of gelling solution concentration influenced the microbead Cu(II) content, size, biomechanical properties, Cu(II) release and subsequently potential biomedical application. The formulations chosen for biomedical evaluation showed potential for antimicrobial and tissue engineering applications. Microbeads with higher Cu(II) loading (~100 μmol g(-1)) induced immediate bactericidal effects against Escherichia coli and Staphylococcus aureus. Conversely, Cu(II) release from microbeads with the Cu(II) content of ~60 μmol g(-1) was slower and they were suitable for promoting and maintaining chondrogenic phenotype of bovine calf chondrocytes in 3D culture. Results of this study have shown possibilities for tuning Cu-alginate properties for potential biomedical applications such as antimicrobial wound dressings, tissue engineering scaffolds or articular cartilage implants. PMID:27305176

  5. Influence of both cation and alginate nature on the rheological behavior of transition metal alginate gels.

    PubMed

    Agulhon, Pierre; Robitzer, Mike; Habas, Jean-Pierre; Quignard, Françoise

    2014-11-01

    The rheological properties of several ionotropic alginate hydrogels were investigated according to the nature of the divalent cation (Mn(2+), Co(2+), Cu(2+)) and the guluronic fraction of the alginate (HG and LG for "high G-content" and "low G-content"). Six hydrogels (Mn-LG, Mn-HG, Co-LG, Co-HG, Cu-LG and Cu-HG) were synthesized and studied by spectromechanical analyses. On one hand, Cu-HG, Cu-LG and Co-HG behaved as viscoelastic solids: the elastic contribution was higher than the dissipative component in all the frequency range studied (G'>G"). No flow zone (G">G') was detected even at very low values of the shearing frequency. On the other, Mn-HG, Mn-LG and Co-LG presented a spectromechanical behavior that resembled that observed classically for entangled polymers. Indeed, at high frequency, these latter materials could be compared to a viscoelastic solid but at low frequency, the flow zone was described and the viscous character became prevalent with finite relaxation time. Very good correlations with the microscopic structurations of the network were evidenced (rubbery vs. flow zone and fibrillar vs. complex morphology respectively). PMID:25129777

  6. Development of Wax-Incorporated Emulsion Gel Beads for the Encapsulation and Intragastric Floating Delivery of the Active Antioxidant from Tamarindus indica L.

    PubMed

    Soradech, Sitthiphong; Petchtubtim, Intira; Thongdon-A, Jeerayu; Muangman, Thanchanok

    2016-01-01

    In this study, tamarind (Tamarindus indica L.) seed extracts with potential antioxidant activity and toxicity to cancer cells were developed as functional foods and nutraceutical ingredients in the form of emulsion gel beads. Three extracts were obtained from ethanol and water: TSCH50, TSCH95 and TSCH. All extracts exhibited high potential for superoxide anion scavenging activity over the IC50 range < 5-11 µg/mL and had no toxic effects on normal cells, however, the water extract (TSCH) was the most effective due to its free radical scavenging activity and toxicity in mitochondrial membranes of cancer cells. Next a study was designed to develop a new formulation for encapsulation and intragastric floating delivery of tamarind seed extract (TSCH) using wax-incorporated emulsion gel beads, which were prepared using a modified ionotropic gelation technique. Tamarind seed extract at 1% (w/w) was used as the active ingredient in all formulations. The effect of the types and amounts of wax on the encapsulation efficiency and percentage of the active release of alginate gel beads was also investigated. The results demonstrated that the incorporation of both waxes into the gel beads had an effect on the percentage of encapsulation efficiency (%) and the percentage of the active ingredient release. Furthermore, the addition of water insoluble waxes (carnauba and bee wax) significantly retarded the release of the active ingredient. The addition of both waxes had a slight effect on drug release behavior. Nevertheless, the increase in incorporated waxes in all formulations could sustain the percentage of active ingredient release. In conclusion, wax-incorporated emulsion gel beads using a modified ionotropic gelation technique could be applied for the intragastric floating delivery and controlled release of functional food and nutraceutical products for their antioxidant and anticancer capacity. PMID:27011162

  7. Green synthesis and characterization of alginate nanoparticles and its role as a biosorbent for Cr(VI) ions

    NASA Astrophysics Data System (ADS)

    Geetha, P.; Latha, M. S.; Pillai, Saumya S.; Deepa, B.; Santhosh Kumar, K.; Koshy, Mathew

    2016-02-01

    Green synthesis of nanoparticles has attained considerable attention in recent years because of its myriad of applications including drug delivery, tissue engineering and water purification. In the present study, alginate nanoparticles stabilized by honey were prepared by cross-linking aqueous solution of alginate with calcium ions. Honey mediated synthesis has been reported earlier for the production of metal nanoparticles. However no literature is available on the use of this technique for polymeric nanoparticles. Highly stable nanoparticles of 10-100 nm size were generated by this technique. The synthesised nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopic techniques. Potential of using these nanoparticles for heavy metal removal was studied by using Cr(VI) from aqueous solution, where a maximum removal efficiency of 93.5% was obtained. This method was also successfully employed for the production of other polymeric nanoparticles like casein, chitosan and albumin.

  8. Bead-Selected Antitumor Genetic Cell Vaccines

    PubMed Central

    Herrero, MJ; R, Botella; R, Algás; Marco, FM; Aliño, SF

    2008-01-01

    Cancer vaccines have always been in the scope of gene therapy research. One of the most successful approaches has been working with genetically modified tumor cells. However, to become a clinical reality, tumor cells must suffer a long and risky process from the extraction from the patient to the reimplantation as a vaccine. In this work, we explain our group’s approach to reduce the cell number required to achieve an immune response against a melanoma murine model, employing bead-selected B16 tumor cells expressing GM-CSF and B7.2. PMID:21892287

  9. Advanced beaded and tubular structural panels

    NASA Technical Reports Server (NTRS)

    Musgrove, M. D.; Greene, B. E.

    1975-01-01

    A program to develop lightweight beaded and tubular structural panels is described. Applications include external surfaces, where aerodynamically acceptable, and primary structure protected by heat shields. The design configurations were optimized and selected with a computer code which iterates geometric parameters to satisfy strength, stability, and weight constraints. Methods of fabricating these configurations are discussed. Nondestructive testing produced extensive combined compression, shear, and bending test data on local buckling specimens and large panels. The optimized design concepts offer 25 to 30% weight savings compared to conventional stiffened sheet construction.

  10. Postelectrospinning modifications for alginate nanofiber-based wound dressings.

    PubMed

    Leung, Victor; Hartwell, Ryan; Elizei, Sanam Salimi; Yang, Heejae; Ghahary, Aziz; Ko, Frank

    2014-04-01

    Alginate nanofibers have been attractive for potential tissue regeneration applications due to a combination of their moisture retention ability and large surface area available in a nonwoven nanofiber form. This study aims to address several challenges in alginate nanofiber application, including the lack of structural stability in aqueous environment and limited cell attachment as compared to commercial wound dressings, via examining crosslinking techniques. In addition to the commonly performed divalent ion crosslinking, a glutaraldehyde double-crosslinking step and polylysine addition were applied to an electrospun alginate nanofiber nonwoven mat. With optimization of the electrospinning solution, nanofiber morphology was maintained after the two-stage crosslinking process. Extensibility of the nanofiber mat reduced after the crosslinking process. However, both aqueous stability and cell attachment improved after the postspinning modifications, as shown through degradation tests in phosphate buffered saline solutions and fibroblast cell culture studies, respectively. PMID:24155096

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

    PubMed

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

    2015-08-01

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

  12. Fundamental Characteristics of Bioprint on Calcium Alginate Gel

    NASA Astrophysics Data System (ADS)

    Umezu, Shinjiro; Hatta, Tatsuru; Ohmori, Hitoshi

    2013-05-01

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

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

    PubMed Central

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

    2001-01-01

    BACKGROUND/AIM—Carteolol is a β adrenoceptor antagonist used topically to reduce intraocular pressure, typically twice daily. In an effort to provide a once daily dosing regimen, carteolol was formulated with 1% alginic acid. The objective of this study was to evaluate the efficacy and safety of carteolol alginate solution in comparison with standard carteolol solution.
METHODS—This was a double masked, parallel group, multicentre study. Patients with ocular hypertension or open angle glaucoma (n=235) were randomly assigned to receive either carteolol alginate four times daily or standard carteolol solution, twice daily. The masking was maintained through the use of a vehicle in the evening for the alginate group. Patients were evaluated at baseline, 15, 60, and 120 days.
RESULTS—At 0900 (presumed trough) on day 60, mean reductions in intraocular pressure (IOP) from baseline were 6.09 (SD 2.97) and 6.09 (3.18) mm Hg for the standard carteolol and alginate, respectively. At 1100 (presumed peak), mean reductions were 6.51 (2.53) and 6.47 (2.76) mm Hg, respectively. Results were similar at other times (day 15 and day 120). The most common side effect was transient stinging on instillation of drops, which did not differ significantly between groups. There were no differences of note in other ocular or systemic signs or symptoms.
CONCLUSION—The new alginate formulation of carteolol 2% given once daily was as effective as standard carteolol 2% given twice daily with no meaningful differences regarding safety.

 PMID:11466245

  14. Immobilization of proteins on agarose beads, monitored in real time by bead injection spectroscopy

    PubMed Central

    Ruzicka*, Jaromir; Carroll, Andrea D.; Lähdesmäki, Ilkka

    2006-01-01

    Summary This work introduces a novel tool for the examination and optimization of protein immobilization protocols, by measuring the rate and yield of coupling reactions, as they take place on the surface of agarose beads in a well-stirred microreactor. The power of the Bead Injection Spectroscopy (BIS) technique is demonstrated on examples of amino coupling reactions for albumin, ovalbumin, lysozyme, human IgG, ribonuclease A and cytochrome C, using commercially available Aminolink® agarose beads. It was found, surprisingly, that currently recommended protocols for reductive amination can be shortened from several hours to several minutes, and that, contrary to literature data, the yield of coupling is dependent on pH and the isoelectric point of the protein. In addition, leakage of immobilized ligands can be measured by direct spectroscopic interrogation of captured beads in situ. The methodology presented in this work documents that BIS is a useful tool for quality control of agarose-based chromatographic supports, as well as for the optimization of a wide variety of immobilization chemistries, as used for synthesis of chromatographic supports, immobilization of enzymes, and derivatization of biosensing surfaces. PMID:16802025

  15. Characterization of crosslinked polystyrene(PS) beads in SBR matrix

    SciTech Connect

    Cha, Yoon-Jong; Choe, Soonja

    1995-12-01

    Monodisperse sized crosslinked polystyrene(PS) beads were prepared by a reaction of semibatch emulsion polymerization with styrene monomer, divinylbenzene(DVB) crosslinking agent and potassium persulfate(K{sub 2}S{sub 2}O{sub 9}) initiator in the absence of emulsifier. The glass transition temperature(T{sub g}) and the mean diameter of the beads were increased from 100{degrees}C to 135{degrees}C and from 402 nm to 532 nm, respectively, for an incorporation of 2 to 10 mol% DVB. Crosslinking density was also linearly increased with DVB content. SEM microphotographs of SBR composite filled with various contents of PS beads revealed that PS beads are relatively well dispersed without changing the spherical shape of the beads in all range of compositions. In stress-strain analysis, elongation at break and tensile strength of SBR composite were increased with the bead content. Applicability of the PS beads as a filler in SBR matrix is tested by plotting Mooney-Rivlin or Guth-Smallwood equations. However, mechanical properties of the composite with the beads were not so excellent as those of the composite with carbon black. Crosslinked PS beads are still tentative as a white color reinforcing filler on SBR matrix.

  16. Dispersion of fine phosphor particles by newly developed beads mill

    NASA Astrophysics Data System (ADS)

    Joni, I. Made; Panatarani, C.; Maulana, Dwindra W.

    2016-02-01

    Fine phosphor Y2O3:Eu3+ particles has advanced properties compare to conventional particles applied for compact fluorescent lamp (CFL) as three band phosphor. However, suspension of fine particles easily agglomerated during preparation of spray coating of the CFL tube. Therefore, it is introduced newly developed beads mill system to disperse fine phosphor. The beads mill consist of glass beads, dispersing chamber (impellers), separator chamber, slurry pump and motors. The first important performance of beads mill is the performance of the designed on separating the beads with the suspended fine particles. We report the development of beads mill and its separation performance vary in flow rate and separator rotation speeds. The 27 kg of glass beads with 30 µm in size was poured into dispersing chamber and then water was pumped continuously through the slurry pump. The samples for the separation test was obtained every 1 hours vary in rotation speed and slurry flow rate. The results shows that the separation performance was 99.99 % obtained for the rotation speed of >1000 rpm and flow rate of 8 L/minute. The performances of the system was verified by dispersing fine phosphor Y2O3:Eu3+ particles with concentration 1 wt.%. From the observed size distribution of particles after beads mill, it is concluded that the current design of bead mill effectively dispersed fine phosphor Y2O3:Eu3+.

  17. Alginate and Chitosan Gel Nanoparticles for Efficient Protein Entrapment

    NASA Astrophysics Data System (ADS)

    Masalova, O.; Kulikouskaya, V.; Shutava, T.; Agabekov, V.

    Alginate and chitosan nanoparticles were synthesized by ionic gelation of the polymers in the presence of stabilizers (PEG 1500, PEG 6000, TWEEN 80). The stability of 210-240 nm Ca-alginate colloids is affected by nanoparticles ageing and by the presence of a stabilizer. The diameter of chitosan nanoparticles is in the range of 180 to 260 nm and depends on polymer concentration in the reaction mixture, its molecular weight, and stabilizer type. The nanoparticles efficiently entrap a model protein, bovine serum albumin, in the amount up to 0.24 mg per 1 mg of polysaccharide.

  18. Effects of composition and structure of alginates on adsorption of divalent metals

    NASA Astrophysics Data System (ADS)

    Nai-Yu, Zheng; Yan-Xia, Zhang; Xiao, Fan; Li-Jun, Han

    1994-03-01

    Results of a series of experiments (on the adsorption of divalent metal ions by dried alginic acid, Na and Ca alginates of different composition and block structure) conducted in this systematic study of the effects of the composition and structure of alginates on the static adsorption equilibrium of divalent metal ions indicate that the properties of alginate adsorption to divalent metal ions are highly different, depending not only on the cations used, but also on the form and structure of the alginates. There is close correlation between the adsorption properties and the structure of the alginates. The selectivity coefficient of Na alginate for Cd-Sr ion exchange tends to increase with the increase of the M/G ratio in alginate, whereas the adsorption capacity of Ca alginate for Cu2+ ion decrease with the increase of the G-block or the average length of the G-block(bar N_G ) and the total adsorption capacity of alginic acid is found to vary in the same order as the F MM(diad frequency) in alginate in the mixed solution of Sr2+, Ba2+ and Cd2+.

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

    PubMed

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

    2016-03-30

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

  20. Getting drowned in a swirl: Deformable bead-spring model microswimmers in external flow fields

    NASA Astrophysics Data System (ADS)

    Küchler, Niklas; Löwen, Hartmut; Menzel, Andreas M.

    2016-02-01

    Deformability is a central feature of many types of microswimmers, e.g., for artificially generated self-propelled droplets. Here, we analyze deformable bead-spring microswimmers in an externally imposed solvent flow field as simple theoretical model systems. We focus on their behavior in a circular swirl flow in two spatial dimensions. Linear (straight) two-bead swimmers are found to circle around the swirl with a slight drift to the outside with increasing activity. In contrast to that, we observe for triangular three-bead or squarelike four-bead swimmers a tendency of being drawn into the swirl and finally getting drowned, although a radial inward component is absent in the flow field. During one cycle around the swirl, the self-propulsion direction of an active triangular or squarelike swimmer remains almost constant, while their orbits become deformed exhibiting an "egglike" shape. Over time, the swirl flow induces slight net rotations of these swimmer types, which leads to net rotations of the egg-shaped orbits. Interestingly, in certain cases, the orbital rotation changes sense when the swimmer approaches the flow singularity. Our predictions can be verified in real-space experiments on artificial microswimmers.

  1. Getting drowned in a swirl: Deformable bead-spring model microswimmers in external flow fields.

    PubMed

    Küchler, Niklas; Löwen, Hartmut; Menzel, Andreas M

    2016-02-01

    Deformability is a central feature of many types of microswimmers, e.g., for artificially generated self-propelled droplets. Here, we analyze deformable bead-spring microswimmers in an externally imposed solvent flow field as simple theoretical model systems. We focus on their behavior in a circular swirl flow in two spatial dimensions. Linear (straight) two-bead swimmers are found to circle around the swirl with a slight drift to the outside with increasing activity. In contrast to that, we observe for triangular three-bead or squarelike four-bead swimmers a tendency of being drawn into the swirl and finally getting drowned, although a radial inward component is absent in the flow field. During one cycle around the swirl, the self-propulsion direction of an active triangular or squarelike swimmer remains almost constant, while their orbits become deformed exhibiting an "egglike" shape. Over time, the swirl flow induces slight net rotations of these swimmer types, which leads to net rotations of the egg-shaped orbits. Interestingly, in certain cases, the orbital rotation changes sense when the swimmer approaches the flow singularity. Our predictions can be verified in real-space experiments on artificial microswimmers. PMID:26986380

  2. Microchannel liquid-flow focusing and cryo-polymerization preparation of supermacroporous cryogel beads for bioseparation.

    PubMed

    Yun, Junxian; Tu, Changming; Lin, Dong-Qiang; Xu, Linhong; Guo, Yantao; Shen, Shaochuan; Zhang, Songhong; Yao, Kejian; Guan, Yi-Xin; Yao, Shan-Jing

    2012-07-20

    Polymeric cryogels are sponge-like materials with supermacroporous structure, allowing them to be of interest as new chromatographic supports, cell scaffolds and drug carriers in biological and biomedical areas. The matrices of cryogels are always prepared in the form of monoliths by cryo-polymerization under frozen conditions. However, there are limited investigations on the production of cryogels in the form of adsorbent beads suitable for bioseparation. In this work, we provide a new approach by combining the microchannel liquid-flow focusing with cryo-polymerization for the preparation of polyacrylamide-based supermacroporous cryogel beads with a narrow particle size distribution. The present method was achieved by introducing the aqueous phase solution containing monomer, cross-linker and redox initiators, and the water-immiscible organic oil phase containing surfactant simultaneously into a microchannel with a cross-shaped junction, where the aqueous drops with uniform sizes were generated by the liquid shearing and the segmentation due to the steady flow focusing of the immiscible phase streams. These liquid drops were in situ suspended into the freezing bulk oil phase for cryo-polymerization and the cryogel matrix beads were obtained by thawing after the achievement of polymerization. By grafting the polymer chains containing sulfo binding groups onto these matrix beads, the cation-exchange cryogel beads for protein separation were produced. The results showed that at the aqueous phase velocities from 0.5 to 2.0 cm/s and the total velocities of the water-immiscible phase from 2.0 to 6.0 cm/s, the obtained cryogel beads by the present method have narrow size distributions with most of the bead diameters in the range from 800 to 1500 μm with supermacropores in sizes of about 3-50 μm. These beads also have high porosities with the averaged maximum porosity of 96.9% and the mean effective porosity of 86.2%, which are close to those of the polyacrylamide

  3. 3D Porous Calcium-Alginate Scaffolds Cell Culture System Improved Human Osteoblast Cell Clusters for Cell Therapy

    PubMed Central

    Chen, Ching-Yun; Ke, Cherng-Jyh; Yen, Ko-Chung; Hsieh, Hui-Chen; Sun, Jui-Sheng; Lin, Feng-Huei

    2015-01-01

    Age-related orthopedic disorders and bone defects have become a critical public health issue, and cell-based therapy is potentially a novel solution for issues surrounding bone tissue engineering and regenerative medicine. Long-term cultures of primary bone cells exhibit phenotypic and functional degeneration; therefore, culturing cells or tissues suitable for clinical use remain a challenge. A platform consisting of human osteoblasts (hOBs), calcium-alginate (Ca-Alginate) scaffolds, and a self-made bioreactor system was established for autologous transplantation of human osteoblast cell clusters. The Ca-Alginate scaffold facilitated the growth and differentiation of human bone cell clusters, and the functionally-closed process bioreactor system supplied the soluble nutrients and osteogenic signals required to maintain the cell viability. This system preserved the proliferative ability of cells and cell viability and up-regulated bone-related gene expression and biological apatite crystals formation. The bone-like tissue generated could be extracted by removal of calcium ions via ethylenediaminetetraacetic acid (EDTA) chelation, and exhibited a size suitable for injection. The described strategy could be used in therapeutic application and opens new avenues for surgical interventions to correct skeletal defects. PMID:25825603

  4. Alginate Hydrogels Coated with Chitosan for Wound Dressing

    PubMed Central

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

    2015-01-01

    In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics. PMID:25969981

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

    PubMed

    Patil, Nilam H; Devarajan, Padma V

    2016-01-01

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

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

    PubMed

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

    2008-09-01

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

  7. Inhibition of tobramycin diffusion by binding to alginate.

    PubMed Central

    Nichols, W W; Dorrington, S M; Slack, M P; Walmsley, H L

    1988-01-01

    [3H]tobramycin bound to sodium alginate and to exopolysaccharide prepared from two mucoid strains of Pseudomonas aeruginosa. Binding to sodium alginate was similar to binding to exopolysaccharide, both in the dependence on tobramycin concentration and in the maximum binding observed at saturation. Incorporation of sodium alginate into agar plates reduced the zone sizes of growth inhibition caused by tobramycin. The reductions in zone sizes were quantitatively accounted for by the binding of tobramycin to sodium alginate during diffusion of the antibiotic away from the well in which it had been placed at the start of the experiment. However, the binding of tobramycin to the exopolysaccharide of P. aeruginosa, and the resulting inhibition of diffusion of the antibiotic, did not significantly increase the penetration time of a spherical microcolony with a radius of 125 micron, such as might be found in the respiratory tract of a patient with cystic fibrosis (from a 90% penetration time of 12 s in the absence of exopolysaccharide to one of 35 s with an exopolysaccharide concentration of 1.0% [wt/vol]). PMID:3132093

  8. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Propylene glycol alginate. 172.858 Section 172.858 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives §...

  9. Chitosan and alginate scaffolds for bone tissue regeneration.

    PubMed

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

    2007-06-01

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

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

    PubMed

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

    2016-09-01

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

  11. Bioinspired preparation of alginate nanoparticles using microbubble bursting.

    PubMed

    Elsayed, Mohamed; Huang, Jie; Edirisinghe, Mohan

    2015-01-01

    Nanoparticles are considered to be one of the most advanced tools for drug delivery applications. In this research, alginate (a model hydrophilic polymer) nanoparticles 80 to 200 nm in diameter were obtained using microbubble bursting. The natural process of bubble bursting occurs through a number of stages, which consequently produce nano- and microsized droplets via two main production mechanisms, bubble shell disintegration and a jetting process. In this study, nano-sized droplets/particles were obtained by promoting the disintegrating mechanism and suppressing (limiting) the formation of larger microparticles resulting from the jetting mechanism. A T-junction microfluidic device was used to prepare alginate microbubbles with different sizes in a well-controlled manner. The size of the bubbles was varied by controlling two processing parameters, the solution flow rate and the bubbling pressure. Crucially, the bubble size was found to be the determining factor for inducing (or limiting) the bubble shell disintegration mechanism and the size needed to promote this process was influenced by the properties of the solution used for preparing the bubbles, particularly the viscosity. The size of alginate nanoparticles produced via the disintegration mechanism was found to be directly proportional to the viscosity of the alginate solution. PMID:25491969

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

    SciTech Connect

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

    2011-12-31

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

  13. Inhibition of tobramycin diffusion by binding to alginate

    SciTech Connect

    Nichols, W.W.; Dorrington, S.M.; Slack, M.P.; Walmsley, H.L.

    1988-04-01

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

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

    SciTech Connect

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

    2011-08-09

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

  15. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

    PubMed

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

    2016-08-16

    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields. PMID:27481656

  16. Bead Collage: An Arts-Based Research Method

    ERIC Educational Resources Information Center

    Kay, Lisa

    2013-01-01

    In this paper, "bead collage," an arts-based research method that invites participants to reflect, communicate and construct their experience through the manipulation of beads and found objects is explained. Emphasizing the significance of one's personal biography and experiences as a researcher, I discuss how my background as an…

  17. Resonance effects in dielectric beads of coaxial connectors

    NASA Astrophysics Data System (ADS)

    Olbrich, G.

    1984-08-01

    A resonator model for calculating H(11) resonance mode frequencies of coaxial connectors is presented. Theoretical results are compared with measurement results obtained with original beads as well as with enlarged connector models. Operational frequencies and bead resonance frequencies for various connector types are given for applications up to 40 GHz.

  18. Activities to Grow On: Buttons, Beads, and Beans.

    ERIC Educational Resources Information Center

    Gonzolis, Amy; And Others

    1992-01-01

    Presents new ideas for using buttons, beans, and beads as teaching manipulatives for elementary school children. The ideas include a button scavenger hunt, a button count, a cup puppet bean game, a numbers guessing game with beans in jars, and a bead stringing activity. (SM)

  19. Method for preparing spherical ferrite beads and use thereof

    DOEpatents

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.

    2002-01-01

    The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe.sub.12 O.sub.19 or SrFe.sub.12 O.sub.19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe.sub.12 O.sub.19 and SrFe.sub.12 O.sub.19 phase suitable for polishing and incorporation into various microwave devices and components.

  20. Alginate microsphere compositions dictate different mechanisms of complement activation with consequences for cytokine release and leukocyte activation.

    PubMed

    Ørning, Pontus; Hoem, Kine Samset; Coron, Abba Elizabeth; Skjåk-Bræk, Gudmund; Mollnes, Tom Eirik; Brekke, Ole-Lars; Espevik, Terje; Rokstad, Anne Mari

    2016-05-10

    The inflammatory potential of 12 types of alginate-based microspheres was assessed in a human whole blood model. The inflammatory potential could be categorized from low to high based on the four main alginate microsphere types; alginate microbeads, liquefied core poly-l-ornithine (PLO)-containing microcapsules, liquefied core poly-l-lysine (PLL)-containing microcapsules, and solid core PLL-containing microcapsules. No complement or inflammatory cytokine activation was detected for the Ca/Ba alginate microbeads. Liquefied core PLO- and PLL-containing microcapsules induced significant fluid phase complement activation (TCC), but with low complement surface deposition (anti-C3c), and a low proinflammatory cytokine secretion, with exception of an elevated MCP-1(CCL2) secretion. The solid core PLL-containing microcapsules generated lower TCC but a marked complement surface deposition and significant induction of the proinflammatory cytokines interleukin (IL-1)β, TNF, IL-6, the chemokines IL-8 (CXCL8), and MIP-1α (CCL3) and MCP-1(CCL2). Inhibition with compstatin (C3 inhibitor) completely abolished complement surface deposition, leukocyte adhesion and the proinflammatory cytokines. The C5 inhibitions partly lead to a reduction of the proinflammatory cytokines. The leukocyte adhesion was abolished by inhibitory antibodies against CD18 and partly reduced by CD11b, but not by CD11c. Anti-CD18 significantly reduced the (IL-1)β, TNF, IL-6 and MIP-1α and anti-CD11b significantly reduced the IL-6 and VEGF secretion. MCP-1 was strongly activated by anti-CD18 and anti-CD11b. In conclusion the initial proinflammatory cytokine responses are driven by the microspheres potential to trigger complement C3 (C3b/iC3b) deposition, leukocyte activation and binding through complement receptor CR3 (CD11b/CD18). MCP-1 is one exception dependent on the fluid phase complement activation mediated through CR3. PMID:26993426

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

    PubMed

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

    2002-01-01

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

  2. Sprayable Aerogel Bead Compositions With High Shear Flow Resistance and High Thermal Insulation Value

    NASA Technical Reports Server (NTRS)

    Ou, Danny; Trifu, Roxana; Caggiano, Gregory

    2013-01-01

    A sprayable aerogel insulation has been developed that has good mechanical integrity and lower thermal conductivity than incumbent polyurethane spray-on foam insulation, at similar or lower areal densities, to prevent insulation cracking and debonding in an effort to eliminate the generation of inflight debris. This new, lightweight aerogel under bead form can be used as insulation in various thermal management systems that require low mass and volume, such as cryogenic storage tanks, pipelines, space platforms, and launch vehicles.

  3. Physicochemical properties of alginate/polycaprolactone-based films containing essential oils.

    PubMed

    Salmieri, Stéphane; Lacroix, Monique

    2006-12-27

    Oregano, savory, and cinnamon essential oils (EOs) 1% (w/v) were separately incorporated as natural antioxidant agents in alginate/polycaprolactone-based films. Films were then treated in 2 or 20% (w/v) CaCl2 solutions in order to generate insoluble films. The mechanical properties and the insoluble matter of films were determined. Intermolecular interactions between film components and alginate cross-linkage were characterized by Fourier transform infrared (FTIR) spectroscopy. Surface morphology of the polymer membrane was determined by scanning electron microscopy (SEM) analysis. Antiradical properties of films were also evaluated following a modified colorimetric method using the N,N-diethyl-p-phenylenediamine (DPPD) discoloration test. Results showed that films treatment with CaCl2 (20%) solution increased the percentage of insoluble matter in films but did not enhance their mechanical properties. FTIR analysis showed higher interactions in films treated in CaCl2 solutions despite the concentration used (2 vs 20%). The SEM observations of films showed a smoother surface with a higher density when films were treated in CaCl2 (20%) solution. The DPPD test showed that the oregano-based films had the highest antiradical properties. PMID:17177561

  4. Bead-based microfluidic immunoassay for diagnosis of Johne's disease

    SciTech Connect

    Wadhwa, Ashutosh; Foote, Robert; Shaw, Robert W; Eda, Shigetoshi

    2012-01-01

    Microfluidics technology offers a platform for development of point-of-care diagnostic devices for various infectious diseases. In this study, we examined whether serodiagnosis of Johne s disease (JD) can be conducted in a bead-based microfluidic assay system. Magnetic micro-beads were coated with antigens of the causative agent of JD, Mycobacterium avium subsp. paratuberculosis. The antigen-coated beads were incubated with serum samples of JD-positive or negative serum samples and then with a fluorescently-labeled secondary antibody (SAB). To confirm binding of serum antibodies to the antigen, the beads were subjected to flow cytometric analysis. Different conditions (dilutions of serum and SAB, types of SAB, and types of magnetic beads) were optimized for a great degree of differentiation between the JD-negative and JD-positive samples. Using the optimized conditions, we tested a well-classified set of 155 serum samples from JD negative and JD-positive cattle by using the bead-based flow cytometric assay. Of 105 JD-positive samples, 63 samples (60%) showed higher antibody binding levels than a cut-off value determined by using antibody binding levels of JD-negative samples. In contrast, only 43-49 JD-positive samples showed higher antibody binding levels than the cut-off value when the samples were tested by commercially-available immunoassays. Microfluidic assays were performed by magnetically immobilizing a number of beads within a microchannel of a glass microchip and detecting antibody on the collected beads by laser-induced fluorescence. Antigen-coated magnetic beads treated with bovine serum sample and fluorescently-labeled SAB were loaded into a microchannel to measure the fluorescence (reflecting level of antibody binding) on the beads in the microfluidic system. When the results of five bovine serum samples obtained with the system were compared to those obtained with the flow cytometer, a high level of correlation (linear regression, r2 = 0.994) was

  5. Switchable cell trapping using superparamagnetic beads

    SciTech Connect

    Bryan, M. T.; Smith, K. H.; Real, M. E.; Bashir, M. A.; Fry, P. W.; Fischer, P.; Im, M.-Y.; Schrefl, T.; Allwood, D. A.; Haycock, J. W.

    2010-04-30

    Ni{sub 81}Fe{sub 19} microwires are investigated as the basis of a switchable template for positioning magnetically-labeled neural Schwann cells. Magnetic transmission X-ray microscopy and micromagnetic modeling show that magnetic domain walls can be created or removed in zigzagged structures by an applied magnetic field. Schwann cells containing superparamagnetic beads are trapped by the field emanating from the domain walls. The design allows Schwann cells to be organized on a surface to form a connected network and then released from the surface if required. As aligned Schwann cells can guide nerve regeneration, this technique is of value for developing glial-neuronal co-culture models in the future treatment of peripheral nerve injuries.

  6. Scanning probe measurements on a magnetic bead biosensor

    NASA Astrophysics Data System (ADS)

    Megens, Mischa; de Theije, Femke; de Boer, Bart; van Gaal, Frans

    2007-07-01

    We experimentally demonstrate the sensitivity of an integrated detection scheme for small superparamagnetic beads, intended for medical diagnostic applications. Detection is based on the giant magnetoresistance effect of a 100×3μm2 magnetic multilayer strip. A conductive wire to magnetize the superparamagnetic beads is integrated on the same substrate. By scanning a single bead over the wires and sensor strip using an atomic force microscope, we simultaneously measure topography and sensor resistivity in a three-dimensional volume above the sensor. The observations can be explained well by means of the macroscopically measured sensor resistivity curve and the magnetization of the beads, combined with the Biot-Savart law for the magnetic field of the wire. From these encouraging results, we project that it is possible to detect even a single 300nm superparamagnetic bead on our sensor.

  7. Preparation of bead metal single crystals by electron beam heating

    SciTech Connect

    Voigtlaender, Bert; Linke, Udo; Stollwerk, H.; Brona, J.

    2005-11-15

    For the fabrication of small metal bead crystals a gas flame is used to melt a wire forming a liquid droplet which solidifies upon cooling into a single crystal metal bead. Due to oxidation under ambient conditions bead crystals can be formed only from noble metals using this method. Here we describe a method how to fabricate bead crystals from a wide variety of metals and metal alloys (Cu, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Ir, Pt, Au, PtPd, Pd{sub 80}Pt{sub 20}, PtRh, AuAg, and PtIr) by electron beam heating under vacuum conditions. Narrow x-ray diffraction peaks confirm a high crystal quality of the bead crystals.

  8. Feasibility of using alginate to absorb dissolved copper from aqueous media

    SciTech Connect

    Jang, L.K.; Brand, W.; Resong, M.; Mainieri, W.; Geesey, G.G. )

    1990-11-01

    Alginate (a biopolymer from kelp and some bacterial strains) is known to absorb copper favorably in the presence of other cations. In this work, the feasibility of using a 2-liter batch three-phase (air/liquid/alginate gel) loop fluidized bed reactor to polish water containing 10-150 ppm dissolved copper was investigated. Three methods were tested: (1) calcium alginate spheres, prepared by dispensing sodium alginate (3.2 wt. % in water) into a 0.05 M calcium nitrate solution, were used as the absorbent, (2) the alginate spheres were formed in situ by dispensing the sodium alginate solution directly into the reactor fluid, and (3) same as (2) except that a trace amount of EDTA was added to the alginate solution. Batch absorption data showed that Method 3 yielded the best result; the concentration of dissolved copper was successfully reduced from 140 ppm to 10 ppm with 3.2 g sodium alginate and 0.2 g EDTA used. However, when the initial concentration was below 40 ppm, both Method 2 and Method 3 are not recommended because the concentration of dissolved copper was too low to allow in situ formation of alginate spheres. Method 1 was found to be useful for treating water containing 10 ppm dissolved copper. But the competition from calcium seriously affected the effective capacity of the alginate for copper. The application of the classical shell progressive model to describe the absorption kinetics was discussed.

  9. Preparation and characterization of superparamagnetic iron oxide nanoparticles stabilized by alginate.

    PubMed

    Ma, Hui-li; Qi, Xian-rong; Maitani, Yoshie; Nagai, Tsuneji

    2007-03-21

    SPION with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications. In this study, SPION stabilized by alginate (SPION-alginate) were prepared by a modified coprecipitation method. The structure, size, morphology, magnetic property and relaxivity of the SPION-alginate were characterized systematically by means of XRD, TEM, ESEM, AFM, DLS, SQUID magnetometer and MRI, respectively, and the interaction between alginate and iron oxide (Fe(3)O(4)) was characterized by FT-IR and AFM. The results revealed that typical iron oxide nanoparticles were Fe(3)O(4) with a core diameter of 5-10 nm and SPION-alginate had a hydrodynamic diameter of 193.8-483.2 nm. From the magnetization curve, the Ms of a suspension of SPION-alginate was 40 emu/g, corresponding to 73% of that of solid SPION-alginate. This high Ms may be due to the binding of Fe(3)O(4) nanoparticles to alginate macromolecule strands as visually confirmed by AFM. SPION-alginate of several hundred nanometers was stable in size for 12 months at 4 degrees C. Moreover, T1 relaxivity and T2 relaxivity of SPION-alginate in saline (1.5 T, 20 degrees C) were 7.86+/-0.20 s(-1) mM(-1) and 281.2+/-26.4 s(-1) mM(-1), respectively. PMID:17074454

  10. Calcium alginate matrix increases the stability and recycling capability of immobilized endo-β-1,4-xylanase from Geobacillus stearothermophilus KIBGE-IB29.

    PubMed

    Bibi, Zainab; Qader, Shah Ali Ul; Aman, Afsheen

    2015-07-01

    Exploration of microbial pool from extremely diversified ecosystem is significantly important for various industrial applications. Bacterial communities from extreme habitats including volcanic vents, hot springs, and industrial sectors are eagerly explored for the isolation of thermophiles. Geobacillus stearothermophilus KIBGE-IB29, isolated from blast furnace site of a steel processing industry, is capable of producing thermostable endo-β-1,4-xylanase. In the current study, this enzyme was immobilized within calcium alginate beads using entrapment technique. Amalgamation of sodium alginate (40.0 gL(-1)) and calcium chloride (0.4 M) was used for the formation of immobilized beads. It was observed that temperature (50 °C) and pH (7.0) optima of immobilized enzyme remained same, but enzyme-substrate reaction time increased from 5.0 to 30.0 min as compared to free enzyme. Diffusion limit of high molecular weight xylan (corncob) caused a decline in V max of immobilized enzyme from 4773 to 203.7 U min(-1), whereas K m value increased from 0.5074 to 0.5722 mg ml(-1) with reference to free enzyme. Immobilized endo-β-1,4-xylanase showed its stability even at high temperatures as compared to free enzyme and retained 18 and 9 % residual activity at 70 and 80 °C, respectively. Immobilized enzyme also exhibited sufficient recycling efficiency up to five reaction cycles which indicated that this enzyme can be a plausible candidate in paper and pulp industry. PMID:26001519

  11. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    SciTech Connect

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

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

    PubMed

    Amer, Walid; Abdelouahdi, Karima; Ramananarivo, Hugo Ronald; Fihri, Aziz; El Achaby, Mounir; Zahouily, Mohamed; Barakat, Abdellatif; Djessas, Kamal; Clark, James; Solhy, Abderrahim

    2014-02-01

    In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX). PMID:24411386

  13. Novel composite sorbent beads for paraquat removal by hemoperfusion.

    PubMed

    Tabak, A; Lotan, N; Sideman, S; Taitelman, U

    1983-05-01

    The present report describes the development and performance of a column that is to be used for removal of paraquat from circulating blood in a hemoperfusion-type set-up. The key element of the system is a newly developed sorbent material containing fuller's earth entrapped in cross-linked agarose beads (Talosit). The technique produces a sorbent material exhibiting a very large active surface area while allowing for high mobility of paraquat molecules within the beads and favorable flow characteristics of packed column. Cross-linking of the agarose (by epichlorohydrin) also has a most beneficial effect on the mechanical strength of the beads as well as on their stability to sterilization in an autoclave. The composite beads exhibit good blood compatibility. A scanning electron microscope analysis of the beads showed no adherence of cellular blood components after contact with blood. Moreover, no significant changes in plasma composition had taken place when the beads were properly conditioned prior to contact with fresh human blood. A comparative study of paraquat removal from saline solution by the new beads and by cellulose-coated activated charcoal (Adsorba-300C) indicates a higher removal rate with the former. The results obtained so far with this new sorbent are very promising and extension of these studies to in vivo hemoperfusion is under way. PMID:6870595

  14. Formulation of controlled release gellan gum macro beads of amoxicillin.

    PubMed

    Babu, R Jayachandra; Sathigari, Sateesh; Kumar, M Thilek; Pandit, J K

    2010-01-01

    Gellan gum has been reported to have wide pharmaceutical applications such as tablet binder, disintegrant, gelling agent and as a controlled release polymer. Multiparticulate delivery systems spread out more uniformly in the gastrointestinal tract and reduce the local irritation. The purpose of this study is to explore possible applicability of gellan macro beads as an oral controlled release system of a sparingly soluble drug, amoxicillin. Gellan gum beads were prepared by ionotropic gelation with calcium ions. The effect of drug loading, stirring time, polymer concentration, electrolyte (CaCl2) concentration, curing time etc. influencing the preparation of the gellan gum macro beads and the drug release from gellan gum beads were investigated in this study. Optimal preparation conditions allowed very high incorporation efficiency for amoxicillin (91%) The release kinetics of amoxicillin from gellan beads followed the diffusion model for an inert porous matrix in the order: 0.1 N HCl > phosphate buffer > distilled water. Change in curing time did not significantly affect the release rate constant, but drug concentration, polymer concentration and electrolyte concentration significantly affect the release rate of amoxicillin from the beads. The gellan macro beads may be suitable for gastro retentive controlled delivery of amoxicillin. PMID:19863487

  15. Construction of hydrodynamic bead models from high-resolution X-ray crystallographic or nuclear magnetic resonance data.

    PubMed Central

    Byron, O

    1997-01-01

    Computer software such as HYDRO, based upon a comprehensive body of theoretical work, permits the hydrodynamic modeling of macromolecules in solution, which are represented to the computer interface as an assembly of spheres. The uniqueness of any satisfactory resultant model is optimized by incorporating into the modeling procedure the maximal possible number of criteria to which the bead model must conform. An algorithm (AtoB, for atoms to beads) that permits the direct construction of bead models from high resolution x-ray crystallographic or nuclear magnetic resonance data has now been formulated and tested. Models so generated then act as informed starting estimates for the subsequent iterative modeling procedure, thereby hastening the convergence to reasonable representations of solution conformation. Successful application of this algorithm to several proteins shows that predictions of hydrodynamic parameters, including those concerning solvation, can be confirmed. PMID:8994627

  16. Porous Bead-Based Diagnostic Platforms: Bridging the Gaps in Healthcare

    PubMed Central

    Chou, Jie; Wong, Jorge; Christodoulides, Nicolaos; Floriano, Pierre N.; Sanchez, Ximena; McDevitt, John

    2012-01-01

    Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice field; as it struggles to achieve and expand upon at the point-of-care the quality of results that are achieved now routinely in remote laboratory settings. This review article serves to explore for the first time the key intersection of multiplexed bead-based detection systems with integrated microfluidic structures alongside porous capture elements together with biomarker validation studies. These strategically important elements are evaluated here in the context of platform generation as suitable for near-patient testing. Essential issues related to the scalability of these modular sensor ensembles are explored as are attempts to move such multiplexed and multiclass platforms into large-scale clinical trials. Recent efforts in these bead sensors have shown advantages over planar microarrays in terms of their capacity to generate multiplexed test results with shorter analysis times. Through high surface-to-volume ratios and encoding capabilities; porous bead-based ensembles; when combined with microfluidic elements; allow for high-throughput testing for enzymatic assays; general chemistries; protein; antibody and oligonucleotide applications. PMID:23202219

  17. One-bead-one-compound library of end-capped dipeptides and deconvolution by microflow NMR.

    PubMed

    Simon, Rozalyn A; Schuresko, Laura; Dendukuri, Nagamani; Goers, Emily; Murphy, Brent; Lokey, R Scott

    2005-01-01

    As part of our program to identify novel small molecules with interesting biological activity, we have designed and synthesized a library of end-capped dipeptides with an emphasis on compound diversity, complexity, and membrane permeability. An approximately 1500-member library was synthesized manually on large polystyrene beads using the mix-and-split method. The final compounds were cleaved into 384-well plates to generate individual stock solutions for input into high-throughput biological screens. Individual compounds were decoded using a combination of mass spectrometry and microflow NMR spectroscopy. In principle, this approach to deconvolution obviates the need for complicated binary encoding-decoding strategies for one-bead-one-compound libraries. PMID:16153064

  18. K Basin sludge/resin bead separation test report

    SciTech Connect

    Squier, D.M.

    1998-08-25

    The K Basin sludge is an accumulation of fuel element corrosion products, organic and inorganic ion exchange materials, canister gasket materials, iron and aluminum corrosion products, sand, dirt and minor amounts of other organic material. The sludge will be collected and treated for storage and eventual disposal. This process will remove the large solid materials by a 1/4 inch screen. The screened material will be subjected to nitric acid in a chemical treatment process. The organic ion exchange resin beads produce undesirable chemical reactions with the nitric acid. The resin beads must be removed from the bulk material and treated by another process. An effective bead separation method must extract 95% of the resin bead mass without entraining more than 5% of the other sludge component mass. The test plan I-INF-2729, ``Organic Ion Exchange Resin Separation Methods Evaluation,`` proposed the evaluation of air lift, hydro cyclone, agitated slurry and elutriation resin bead separation methods. This follows the testing strategy outlined in section 4.1 of BNF-2574, ``Testing Strategy to Support the Development of K Basins Sludge Treatment Process``. Engineering study BNF-3128, ``Separation of Organic Ion Exchange Resins from Sludge,`` Rev. 0, focused the evaluation tests on a method that removed the fine sludge particles by a sieve and then extracted the beads by means of a elutriation column. Ninety-nine percent of the resin beads are larger than 125 microns and 98.5 percent are 300 microns and larger. Particles smaller than 125 microns make up the largest portion of sludge in the K Basins. Eliminating a large part of the sludge`s non-bead component will reduce the quantity that is lifted with the resin beads in the elutriation column. Resin bead particle size distribution measurements are given in Appendix A The Engineering Testing Laboratory conducted measurements of a elutriation column`s ability to extract resin beads from a sieved, non-radioactive sludge

  19. Ultrasensitive proteome analysis using paramagnetic bead technology

    PubMed Central

    Hughes, Christopher S; Foehr, Sophia; Garfield, David A; Furlong, Eileen E; Steinmetz, Lars M; Krijgsveld, Jeroen

    2014-01-01

    In order to obtain a systems-level understanding of a complex biological system, detailed proteome information is essential. Despite great progress in proteomics technologies, thorough interrogation of the proteome from quantity-limited biological samples is hampered by inefficiencies during processing. To address these challenges, here we introduce a novel protocol using paramagnetic beads, termed Single-Pot Solid-Phase-enhanced Sample Preparation (SP3). SP3 provides a rapid and unbiased means of proteomic sample preparation in a single tube that facilitates ultrasensitive analysis by outperforming existing protocols in terms of efficiency, scalability, speed, throughput, and flexibility. To illustrate these benefits, characterization of 1,000 HeLa cells and single Drosophila embryos is used to establish that SP3 provides an enhanced platform for profiling proteomes derived from sub-microgram amounts of material. These data present a first view of developmental stage-specific proteome dynamics in Drosophila at a single-embryo resolution, permitting characterization of inter-individual expression variation. Together, the findings of this work position SP3 as a superior protocol that facilitates exciting new directions in multiple areas of proteomics ranging from developmental biology to clinical applications. PMID:25358341

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

    PubMed

    Jonathan, Melliana; Souza da Silva, Carol; Bosch, Guido; Schols, Henk; Gruppen, Harry

    2015-04-01

    This study evaluated the intestinal degradability of alginate during 74 days intake in pigs as models for humans. Diets contained pregelatinized starch, retrograded starch, alginate, or a mix of retrograded starch and alginate. Faeces were collected on day 1, 3, 7, 14, 39 and 74. Clear trends in intestinal alginate degradation were observed. Up to day 39, the total tract digestibility of alginate was limited (0.52 ± 0.10), and was lower with the inclusion of retrograded starch in the diet (0.34 ± 0.02). More than 90% of the faecal alginate was insoluble in water, which may explain the low digestibility of the alginate. The digestibility of mannuronic acid (M) was 2-3 times higher than that of guluronic acid (G). The changes of G:M ratio and the relative amounts of alginate oligosaccharides between day 39 and 74 indicated that the microbiota needed more than 39 days to adapt to alginate. This study demonstrated that in-depth analyses of dietary fibres are valuable in understanding the fate of the dietary fibres in the large intestine as it was shown that degradation of a dietary fibre depends not only on the properties of the fibre itself, but also on the other dietary fibres present in the diet and the adaptation time. PMID:25442531