Preparation of bismuth titanate/calcium alginate composite bead and its photocatalytic degradation of dye pollutants

NASA Astrophysics Data System (ADS)

Gan, Huihui; Dong, Nanyang; Lu, Linxiao; Fu, Yan; Zhang, Huining; Qian, Yongxin; Zhang, Kefeng; Jin, Huixia

2017-08-01

In this study, the bismuth titanate/calcium alginate composite bead was synthesized by immobilizing bismuth titanate Bi4Ti3O12 particles into 1.5% sodium alginate (SA) matrix. The Bi4Ti3O12 particles were characterized by X-ray diffraction (XRD). The photocatalytic activity for the degradation of dye Rhodamine B in solution by as-prepared bismuth titanate/calcium alginate composite bead was investigated. The as-prepared composite beads CA/BTO-700 exhibited best photocatalytic efficiency for the degradation of RhB compared with CA/BTO-800 and CA/BTO-900 under simulated solar light. After 4 cycles in photocatalytic degradation of RhB, the degradation rate of the CA/BTO-700 nearly remained unchanged.

Ionic liquid as a potential solvent for preparation of collagen-alginate-hydroxyapatite beads as bone filler.

PubMed

Iqbal, Bushra; Sarfaraz, Zenab; Muhammad, Nawshad; Ahmad, Pervaiz; Iqbal, Jibran; Khan, Zia Ul Haq; Gonfa, Girma; Iqbal, Farasat; Jamal, Arshad; Rahim, Abdur

2018-07-01

In this study, collagen/alginate/hydroxyapatite beads having different proportions were prepared as bone fillers for the restoration of osteological defects. Ionic liquid was used to dissolve the collagen and subsequently the solution was mixed with sodium alginate solution. Hydroxyapatite was added in different proportions, with the rationale to enhance mechanical as well as biological properties. The prepared solutions were given characteristic bead shapes by dropwise addition into calcium chloride solution. The prepared beads were characterized using FTIR, XRD, TGA and SEM analysis. Microhardness testing was used to evaluate the mechanical properties. The prepared beads were investigated for water adsorption behavior to ascertain its ability for body fluid uptake and adjusted accordingly to the bone cavity. Drug loading and subsequently the antibacterial activity was investigated for the prepared beads. The biocompatibility was assessed using the hemolysis testing and cell proliferation assay. The prepared collagen-alginate-HA beads, having biocompatibility and good mechanical properties, have showed an option of promising biologically active bone fillers for bone regeneration.

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).

Phenol biodegradation by immobilized Pseudomonas putida FNCC-0071 cells in alginate beads

NASA Astrophysics Data System (ADS)

Hakim, Lukman Nul; Rochmadi, Sutijan

2017-06-01

Phenol is one of industrial liquid waste which is harmful to the environment, so it must be degraded. It can be degraded by immobilized Pseudomonas putida FNCC-0071 cells. It needs the kinetics and mass transfer data to design this process which can be estimated by the proposed dynamic model in this study. This model involves simultaneous diffusion and reaction in the alginate bead and liquid bulk. The preliminary stage of phenol biodegradation process was acclimatization cells. This is the stage where cells were acclimated to phenol as carbon source (substrate). Then the acclimated cells were immobilized in alginate beads by extrusion method. The variation of the initial phenol concentration in the solution is 350 to 850 ppm where 60 g alginate bead contained by cells loaded into its solution in reactor batch, so then biodegradation occurs. In this study, the average radius of alginate bead was 0.152 cm. The occurred kinetic reaction process can be explained by Blanch kinetic model with the decreasing of parameter μmax' while the increasing values of initial phenol concentration in the same time, but the parameters KM, KM', and kt were increasing by the rising values of initial phenol concentration. The value of the parameter β is almost zero. Effective diffusivity of phenol and cells are 1.11 × 10-5±4.5% cm2 s-1 and 1.39 × 10-7± 0.04% cm2 s-1. The partition coefficient of phenol and cells are 0.39 ± 15% and 2.22 ± 18%.

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

PubMed

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

2008-02-28

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

Novel biochar-impregnated calcium alginate beads with improved water holding and nutrient retention properties.

PubMed

Wang, Bing; Gao, Bin; Zimmerman, Andrew R; Zheng, Yulin; Lyu, Honghong

2018-03-01

Drought conditions and nutrients loss have serious impacts on soil quality as well as crop yields in agroecosystems. New techniques are needed to carry out effective soil water and nutrient conservation and fertilizer application tools. Here, calcium alginate (CA) beads impregnated with ball-milled biochar (BMB) were investigated as a new type of water/nutrients retention agent. Both CA and Ca-alginate/ball milled biochar composite (CA-BMB) beads showed high kinetic swelling ratios in KNO 3 solution and low kinetic swelling ratios in water, indicating that CA-BMB beads have the potential to retain mineral nitrogen and nutrients by ion exchange. Pseudo-second-order kinetic model well-described the swelling kinetics of both beads in KNO 3 solution. Over a range of temperatures, the characteristics of dehydration suggested that impregnation with BMB improved the water holding capacity and postponed the dehydration time of Ca-alginate. The cumulative swelling and release characteristics of water, K + , and NO 3 - indicated that CA-BMB beads have great potential as a soil amendment to improve its nutrient retention and water holding capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-08-01

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

Magnetic alginate beads for Pb(II) ions removal from wastewater.

PubMed

Bée, Agnès; Talbot, Delphine; Abramson, Sébastien; Dupuis, Vincent

2011-10-15

A magnetic adsorbent (called magsorbent) was developed by encapsulation of magnetic functionalized nanoparticles in calcium-alginate beads. The adsorption of Pb(II) ions by these magnetic beads was studied and the effect of different parameters, such as initial concentration, contact time and solution pH value on the adsorption of Pb(II) ions was investigated. Our magsorbent was found to be efficient to adsorb Pb(II) ions and maximal adsorption capacity occurred at pH 2.3-6. The classical Langmuir model used to fit the experimental adsorption data showed a maximum sorption capacity close to 100 mg g(-1). The experimental kinetic data were well correlated with a pseudo second-order model, 50% of the Pb(II) ions were removed within 20 min and the equilibrium was attained around 100 min. Moreover our magsorbent was easily collected from aqueous media by using an external magnetic field. These results permitted to conclude that magnetic alginate beads could be efficiently used to remove heavy metals in a water treatment process. Copyright © 2011 Elsevier Inc. All rights reserved.

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

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

PubMed

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

2008-07-01

Diffusion characteristics of chlorferon and diethylthiophosphate (DETP) in Ca-alginate gel beads were studied to assist in designing and operating bioreactor systems. Diffusion coefficients for chlorferon and DETP in Ca-alginate gel beads determined at conditions suitable for biodegradation studies were 2.70 x 10(-11) m(2)/s and 4.28 x 10(-11) m(2)/s, respectively. Diffusivities of chlorferon and DETP were influenced by several factors, including viscosity of the bulk solution, agitation speed, and the concentrations of diffusing substrate and immobilized cells. Diffusion coefficients increased with increasing agitation speed, probably due to poor mixing at low speed and some attrition of beads at high speeds. Diffusion coefficients also increased with decreasing substrate concentration. Increased cell concentration in the gel beads caused lower diffusivity. Theoretical models to predict diffusivities as a function of cell weight fraction overestimated the effective diffusivities for both chlorferon and DETP, but linear relations between effective diffusivity and cell weight fraction were derived from experimental data. Calcium-alginate gel beads with radii of 1.65-1.70 mm used in this study were not subject to diffusional limitations: external mass transfer resistances were negligible based on Biot number calculations and effectiveness factors indicated that internal mass transfer resistance was negligible. Therefore, the degradation rates of chlorferon and DETP inside Ca-alginate gel beads were reaction-limited. (c) 2007 Wiley Periodicals, Inc.

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

PubMed

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

2016-01-01

The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

A comparative histological study of alginate beads as a promising controlled release delivery for mefenamic acid.

PubMed

Sevgi, Ferhan; Kaynarsoy, Buket; Ozyazici, Mine; Pekcetin, Cetin; Ozyurt, Dogan

2008-01-01

The new mefenamic acid-alginate bead formulation prepared by ionotropic gelation method using 3 x 2(2) factorial design has shown adequate controlled release properties in vitro. In the present study, the irritation effects of mefenamic acid (MA), a prominent non-steroidal anti-inflammatory (NSAI) drug, were evaluated on rat gastric and duodenal mucosa when suspended in 0.5% (w/v) sodiumcarboxymethylcellulose (NaCMC) solution and loaded in alginate beads. Wistar albino rats weighing 200 +/- 50 g were used during in vivo animal studies. In this work, biodegradable controlled release MA beads and free MA were evaluated according to the degree of gastric or duodenal damage following oral administration in rats. The gastric and duodenal mucosa was examined for any haemorrhagic changes. Formulation code A10 showing both Case II transport and zero order drug release and t(50) % value of 5.22 h was chosen for in vivo animal studies. For in vivo trials, free MA (100 mgkg(-1)), blank and MA (100 mgkg(-1)) loaded alginate beads (formulation code A10) were suspended in 0.5% (w/v) NaCMC solution and each group was given to six rats orally by gavage. NaCMC solution was used as a control in experimental studies. In vivo data showed that the administration of MA in alginate beads prevented the gastric lesions.

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

PubMed

Nayak, Amit Kumar; Pal, Dilipkumar

2013-08-01

The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Study of the physical properties of calcium alginate hydrogel beads containing vineyard pruning waste for dye removal.

PubMed

Vecino, X; Devesa-Rey, R; Cruz, J M; Moldes, A B

2015-01-22

In this work the morphological and surface properties of a biocomposite formulated with vineyard pruning waste entrapped in calcium alginate hydrogel beads were studied. The formulation of the calcium alginate hydrogel beads, containing vineyard pruning waste, was based on the capacity of this green adsorbent to remove dye compounds from wastewater, observing that in the optimum condition (1.25% of cellulosic residue, 2.2% of sodium alginate and 0.475 mol L(-1) CaCl2) the percentage of dyes was reduced up to 74.6%. At lower concentration of CaCl2, high-resolution optical images show that the elongation of the vineyard-alginate biocomposite decreased, whereas the compactness increased. Moreover, higher concentrations of cellulosic residue increased the biocomposite roundness in comparison with biocomposite without the cellulosic residue. Interferometric perfilometry analysis (Ra, Rq, Rz and Rt) revealed that high concentrations of CaCl2 increased the roughness of the of the calcium alginate hydrogel beads observing vesicles in the external surface. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

PubMed

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

2016-01-01

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

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

Alginate-based polysaccharide beads for cationic contaminant sorption from water

Treesearch

Mei Li; Thomas Elder; Gisela Buschle-Diller

2016-01-01

Massive amounts of agricultural and industrial water worldwide are polluted by different types of contaminants that harm the environment and impact human health. Removing the contaminants from effluents by adsorbent materials made from abundant, inexpensive polysaccharides is a feasible approach to deal with this problem. In this research, alginate beads combined with...

Encapsulation of lactase in Ca(II)-alginate beads: Effect of stabilizers and drying methods.

PubMed

Traffano-Schiffo, Maria Victoria; Castro-Giraldez, Marta; Fito, Pedro J; Santagapita, Patricio R

2017-10-01

The purpose of the present work was to analyze the effect of trehalose, arabic and guar gums on the preservation of β-galactosidase activity in freeze-dried and vacuum dried Ca(II)-alginate beads. Freezing process was also studied as a first step of freeze-drying. Trehalose was critical for β-galactosidase conservation, and guar gum as a second excipient showed the highest conservation effect (close to 95%). Systems with T g values ~40°C which were stables at ambient temperature were obtained, being trehalose the main responsible of the formation of an amorphous matrix. Vacuum dried beads showed smaller size (with Feret's diameter below 1.08±0.09mm), higher circularity (reaching 0.78±0.06) and large cracks in their surface than freeze-dried beads, which were more spongy and voluminous. Ice crystallization of the beads revealed that the crystallization of Ca(II)-alginate system follows the Avrami kinetics of nucleation and growth. Particularly, Ca(II)-alginate showed an Avrami index of 2.03±0.07, which means that crystal growing is bidimensional. Neither the addition of trehalose nor gums affected the dimension of the ice growing or its rate. These results open an opportunity in the development of new lactic products able to be consumed by lactose intolerance people. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of organic dyes by magnetic alginate beads.

PubMed

Rocher, Vincent; Siaugue, Jean-Michel; Cabuil, Valérie; Bee, Agnès

2008-02-01

This study deals with the development of a clean and safe process for water pollution remediation. We have synthesized a magnetic adsorbent in order to develop a solid-phase extraction process assisted by a magnetic field. To follow an 'ecoconception' approach, magnetic beads containing magnetic nanoparticles and activated carbon are prepared with a biopolymer extracted from algae, sodium alginate. The use of renewable bioresources of low cost and those disposable in large amount allows the development of a product with a low impact on the environment. The adsorption properties of activated carbon and magnetic properties of iron oxide nanoparticles are combined to produce an interesting magnetic composite. Synthesis and characterization of the magnetic beads have been reported. Their adsorption capacity was investigated by measuring the removal of two dyes (methylene blue and methyl orange) of different charges from aqueous solutions. The efficiency of the beads has been compared with that of non-encapsulated activated carbon. The effects of initial dye concentration, pH and calcium content of the beads have been studied. Adsorption kinetics experiments have been carried out and the data have been well fitted by a pseudo-second-order equation.

Dye decolorization and detoxification potential of Ca-alginate beads immobilized manganese peroxidase.

PubMed

Bilal, Muhammad; Asgher, Muhammad

2015-12-10

In view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry. In present study, a promising and eco-friendly entrapment approach was adopted to immobilize purified manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum IBL-05 on Ca-alginate beads. The immobilized MnP was subsequently used for enhanced decolorization and detoxification of textile reactive dyes). MnP isolated from solid-state culture of G. lucidum IBL-05, presented highest immobilization yield (83.9 %) using alginate beads prepared at optimized conditions of 4 % (w/v) sodium alginate, 2 % (w/v) Calcium chloride (CaCl2) and 0.5 mg/ml enzyme concentration. Immobilization of MnP enhanced optimum temperature but caused acidic shift in optimum pH of the enzyme. The immobilized MnP showed optimum activity at pH 4.0 and 60 °C as compared to pH 5.0 and 35 °C for free enzyme. The kinetic parameters K(m) and V(max) of MnP were significantly improved by immobilization. The enhanced catalytic potential of immobilized MnP led to 87.5 %, 82.1 %, 89.4 %, 95.7 % and 83 % decolorization of Sandal-fix Red C4BLN, Sandal-fix Turq Blue GWF, Sandal-fix Foron Blue E2BLN, Sandal-fix Black CKF and Sandal-fix Golden Yellow CRL dyes, respectively. The insolubilized MnP was reusable for 7 repeated cycles in dye color removal. Furthermore, immobilized MnP also caused a significant reduction in biochemical oxygen demand (BOD) (94.61-95.47 %), chemical oxygen demand (COD) (91.18-94.85 %), and total organic carbon (TOC) (89.58-95 %) of aqueous dye solutions. G. lucidum MnP was immobilized in Ca-alginate beads by entrapment method to improve its practical effectiveness. Ca-alginate bound MnP was catalytically more vigorous, thermo-stable, reusable and worked over wider ranges of pH and temperature as compared to its free counterpart. Results of cytotoxicity like

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

Analysis of removal of cadmium by action of immobilized Chlorella sp. micro-algae in alginate beads

PubMed Central

Valdez, Christian; Perengüez, Yomaira; Mátyás, Bence; Guevara, María Fernanda

2018-01-01

Cadmium (Cd) is a metal that can negatively interfere with the metabolic systems of living beings. The objective of this work was to evaluate the capacity for cadmium removal in aqueous solutions by immobilized Chlorella sp. in calcium alginate beads. Beads without Chlorella sp. were used as a control. All the treatments were established in triplicate for 80 min, at four concentrations of cadmium (0, 20, 100 and 200 ppm), taking samples of aqueous solution every 10 min, to be read using atomic absorption equipment. The study determined that the treatment of alginate beads with immobilized Chlorella sp. removed 59.67% of cadmium at an initial concentration of 20 ppm, this being the best removal result. PMID:29399326

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

PubMed

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

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.

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

Efficient biodegradation of cyanide and ferrocyanide by Na-alginate beads immobilized with fungal cells of Trichoderma koningii.

PubMed

Zhou, Xiaoying; Liu, Lixing; Chen, Yunpeng; Xu, Shufa; Chen, Jie

2007-09-01

Cyanide or metal cyanide contaminations have become serious environmental and food-health problems. A fungal mutant of Trichoderma koningii, TkA8, constructed by restriction enzyme-mediated integration, has been verified to have a high cyanide degradation ability in our previous study. In this study, the mutant cells were entrapped in sodium-alginate (Na-alginate) immobilization beads to degrade cyanide and ferrocyanide in a liquid mineral medium. The results showed that the fungus in immobilization beads consisting of 3% Na-alginate and 3% CaCl2 could degrade cyanide more efficiently than a nonimmobilized fungal culture. For maximum degradation efficiency, the optimal ratio of Na-alginate and wet fungal biomass was 20:1 (m/m) and the initial pH was 6.5. In comparison, cell immobilization took at least 3 and 8 days earlier, respectively, to completely degrade cyanide and ferrocyanide. In addition, we showed that the immobilized beads could be easily recovered from the medium and reused for up to 5 batches without significant losses of fungal remediation abilities. The results of this study provide a promising alternative method for the large-scale remediation of soil or water systems from cyanide contamination.

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

PubMed

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

2013-08-01

Silver nanoparticles (AgNPs)-alginate composite beads were synthesized using three different approaches as filler materials of packed columns for simultaneous filtration-disinfection as an alternative portable water treatment process. The prepared composite beads were packed into a column through which Escherichia coli containing water was filtered to evaluate the disinfection efficacy. Excellent disinfection performance (no detectable viable colony) was achieved with a hydraulic retention time (HRT) as short as 1 min (the shortest tested) with the SGR (Simultaneous-Gelation-Reduction) and AR (Adsorption-Reduction) beads that were prepared using in situ reduction of Ag(+). Comparatively, the SGR beads released significantly less Ag(+)/AgNPs than the AR beads did within the same HRT. From the results of this study it was identified that SGR may be the best choice among all three different synthesis approaches in that the SGR beads can achieve satisfactory bactericidal performance with a relatively low material consumption rate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nitrate removal from drinking water through the use of encapsulated microorganisms in alginate beads.

PubMed

Liu, S X; Hermanowicz, S W; Peng, M

2003-09-01

Biological treatment for removal of nitrate from drinking water is of great significance, as traditional physical and chemical methods could not effectively remove soluble nitrate. In this report immobilized microorganisms with co-immobilized calcium tartrate were used for reducing nitrate concentration (110 mg l(-1) NO3-N) in a model solution. The carbon source also functions as a stabilizing agent for the immobilization matrix. Experiments of denitrification showed a high nitrate removal rate while nitrite residual was at a concentration higher than expected. The nitrate concentration was reduced to nearly zero (0.2-1.4 mg l(-1)) after 3 days of operation. The calcium tartrate (4%, w/w) co-immobilized alginate beads had better nitrate removal performance than tartrate in solution. The nitrite-N residual concentration was approximately 1.1-2.9 mg l(-1) at the end of the experiments, showing the desirability of further denitrification. The stability of alginate beads was also tested both to evaluate their behaviors and investigate the efficacy of bead recycling. It was found that the beads could be used for 8-13 days consecutively without any structural deterioration and leaking of microbes.

Production of tannase by the immobilized cells of Bacillus licheniformis KBR6 in Ca-alginate beads.

PubMed

Mohapatra, P K D; Mondal, K C; Pati, B R

2007-06-01

The present study was aimed at finding the optimal conditions for immobilization of Bacillus licheniformis KBR6 cells in calcium-alginate (Ca-alginate) beads and determining the operational stability during the production of tannin-acyl-hydrolase (tannase) under semicontinous cultivation. The active cells of B. licheniformis KBR6 were immobilized in Ca-alginate and used for the production of tannase. The influence of alginate concentration (5, 10, 20 and 30 g l(-1)) and initial cell loading on enzyme production were studied. The production of tannase increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 0.56 +/- 0.03 U ml(-1) at 20 g l(-1). This was about 1.70-fold higher than that obtained by free cells. The immobilized cells produced tannase consistently over 13 repeated cycles and reached a maximum level at the third cycle. Scanning electron microscope study indicated that the cells in Ca-alginate beads remain in normal shape. The Ca-alginate entrapment is a promising immobilization method of B. licheniformis KBR6 for repeated tannase production. Tannase production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. This is the first report of tannase production from immobilized bacterial cells. The bacterium under study can produce higher amounts of tannase with respect to other fungal strains within a short cultivation period.

Alginate-caseinate composites: Molecular interactions and characterization of cross-linked beads for the delivery of anticandidals.

PubMed

Khlibsuwan, Rapee; Khunkitti, Watcharee; Pongjanyakul, Thaned

2018-04-19

Polysaccharide-protein composites offer potential utility for the delivery of drugs. The objectives of this work were to investigate the molecular interactions between sodium alginate (SA) and sodium caseinate (SC) in dispersions and films and to characterize calcium alginate (CA) beads mixed with SC for the delivery of fluconazole (FZ) and clotrimazole (CZ). The results demonstrated that SA could interact with SC, which caused a viscosity synergism in the dispersions. Hydrogen bonding between the carboxyl or hydroxyl groups of SA and the amide groups of SC led to the formation of soluble complexes that could reinforce the CA beads prepared by calcium cross-linking. The SC-CA beads provided higher drug entrapment efficiency, lower water uptake and erosion, and slower drug release than for the CA beads. The loaded FZ was an amorphous form, but CZ crystals were embedded in the bead matrix due to the low water solubility of this drug. However, SC micellization could enhance the water solubility and efficacy of CZ against Candida albicans. This finding indicates that SA can interact with SC via hydrogen bonding to form complexes and that the anticandidal-loaded SC-CA beads can be used as drug delivery systems and drug reservoirs in tablets for oral candidiasis. Copyright © 2018 Elsevier B.V. All rights reserved.

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. Copyright © 2015. Published by Elsevier Ltd.

Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3.

PubMed

Kureel, M K; Geed, S R; Giri, B S; Rai, B N; Singh, R S

2017-10-01

Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×10 8 CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC-MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µ max /K s ; L/mg·day ) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (K i ; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adsorption of arsenic by activated carbon, calcium alginate and their composite beads.

PubMed

Hassan, A F; Abdel-Mohsen, A M; Elhadidy, H

2014-07-01

The present investigation deals with preparation of three different adsorbent materials namely; potassium hydroxide activated carbon based apricot stone (C), calcium alginate beads (G) and calcium alginate/activated carbon composite beads (GC) were used for the removal of arsenic. The prepared adsorbent materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), N2-adsorption at -196°C and point of zero charge. From the obtained results, it was found that the porosity, surface area and total pore volume of the adsorbent material C>GC>G respectively, however, the G adsorbent has more acidic function group than the other adsorbents. The influence of pH, time, temperature and initial concentration of arsenic(V) were studied and optimized. GC exhibits the maximum As(V) adsorption (66.7mg/g at 30°C). The adsorption of arsenic ions was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also the endothermic spontaneous and a physisorption process. Copyright © 2014 Elsevier B.V. All rights reserved.

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. Copyright © 2015 Elsevier Inc. All rights reserved.

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

PubMed

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

2010-04-15

Nowadays, many researchers have studied the environmental application of the nanoscale zero-valent iron (nZVI) and several field applications for the groundwater remediation have been reported. Still, there are many concerns on the fate and transport of the nZVI and the corresponding risks. To avoid such concerns, it was investigated to immobilize nZVI in a support and then it was applied to degrade trichloroethylene (TCE). The nZVI and palladium-doped nZVI (Fe(0)- and Fe/Pd-alginate) were immobilized in the alginate bead where ferric and barium ions are used as the cross-linking cations of the bead. According to TEM (transmission electron microscopy), the size of the immobilized ZVI was as small as a few nanometers. From the surface analysis of the Fe/Pd-alginate, it is found that the immobilized nZVI has the core-shell structure. The core is composed of single crystal Fe(0), while most of irons on the surface are oxidized to Fe(3+). When 50 g/L of Fe/Pd-alginate (3.7 g Fe/L) was introduced to the aqueous solution, >99.8% of TCE was removed and the release of metal from the support was <3% of the loaded iron. The removal of TCE by Fe/Pd-alginate followed pseudo-first-order kinetics. The observed pseudo-first-order reaction constant (k(obs)) of Fe/Pd-alginate was 6.11 h(-1) and the mass normalized rate constant (k(m)) was 1.6 L h(-1) g(-1). The k(m) is the same order of magnitude with that of iron nanoparticles. In conclusion, it is considered that Fe/Pd-alginate can be used efficiently in the treatment of chlorinated solvent. 2009 Elsevier B.V. All rights reserved.

Impact of plant growth-promoting rhizobacteria on root colonization potential and life cycle of Rhizophagus irregularis following co-entrapment into alginate beads.

PubMed

Loján, P; Demortier, M; Velivelli, S L S; Pfeiffer, S; Suárez, J P; de Vos, P; Prestwich, B D; Sessitsch, A; Declerck, S

2017-02-01

This study aimed at evaluating the impact of seven plant growth-promoting rhizobacteria (PGPR) on root colonization and life cycle of Rhizophagus irregularis MUCL 41833 when co-entrapped in alginate beads. Two in vitro experiments were conducted. The first consisted of the immobilization of R. irregularis and seven PGPR isolates into alginate beads to assess the effect of the bacteria on the pre-symbiotic growth of the fungus. In the second experiment, the best performing PGPR from experiment 1 was tested for its ability to promote the symbiotic development of the AMF in potato plantlets from three cultivars. Results showed that only one isolate identified as Pseudomonas plecoglossicida (R-67094) promoted germ tube elongation and hyphal branching of germinated spores during the pre-symbiotic phase of the fungus. This PGPR further promoted the symbiotic development of the AMF in potato plants. The co-entrapment of Ps. plecoglossicida R-67094 and R. irregularis MUCL 41833 in alginate beads improved root colonization by the AMF and its further life cycle under the experimental conditions. Co-entrapment of suitable AMF-PGPR combinations within alginate beads may represent an innovative technology that can be fine-tuned for the development of efficient consortia-based bioformulations. © 2016 The Society for Applied Microbiology.

Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

PubMed

Taha, M O; Aiedeh, K M; Al-Hiari, Y; Al-Khatib, H

2005-10-01

The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

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

Adsorption of lysozyme by alginate/graphene oxide composite beads with enhanced stability and mechanical property.

PubMed

Li, Jiwei; Ma, Jianwei; Chen, Shaojuan; Huang, Yudong; He, Jinmei

2018-08-01

The large-scale applications of lysozyme in the pharmaceutical industry and food industry require more efficient and cost-effective techniques for its separation/purification. In the present study, graphene oxide (GO) was encapsulated into environmentally benign sodium alginate (SA) to prepare a Ca 2+ crosslinked alginate/graphene oxide composite gel beads (Ca-SA/GO) which were then used to adsorb lysozyme from aqueous solutions. Compared with pure Ca 2+ crosslinked alginate gel beads (Ca-SA), the as-prepared Ca-SA/GO has a lower swelling degree, an improved gel stability in salt solutions, and a higher mechanical performance. This can be explained by the uniform distribution of GO sheets in the Ca-SA matrix and the existence of hydrogen bonding and high interfacial adhesion between GO filler and SA matrix demonstrated by SEM, FTIR, XRD, and TGA. Batch adsorption experiments found that the lysozyme adsorption capacity of Ca-SA/GO can reach 278.28 mg g -1 and it can be regenerated and reused at least 4 times. Moreover, in column adsorption, the Ca-SA/GO showed excellent dynamic adsorption property. With good stability, adsorption capacity, and regeneration ability, the Ca-SA/GO could be a promising adsorbent for lysozyme from aqueous solutions. Copyright © 2018. Published by Elsevier B.V.

Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads.

PubMed

Bai, Jing; Fan, Fangli; Wu, Xiaolei; Tian, Wei; Zhao, Liang; Yin, Xiaojie; Fan, Fuyou; Li, Zhan; Tian, Longlong; Wang, Yang; Qin, Zhi; Guo, Junsheng

2013-12-01

Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH(0), ΔS(0) and ΔG(0) were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous. Copyright © 2013 Elsevier Ltd. All rights reserved.

Production optimization of invertase by Lactobacillus brevis Mm-6 and its immobilization on alginate beads.

PubMed

Awad, Ghada E A; Amer, Hassan; El-Gammal, Eman W; Helmy, Wafaa A; Esawy, Mona A; Elnashar, Magdy M M

2013-04-02

A sequential optimization strategy, based on statistical experimental designs, was employed to enhance the production of invertase by Lactobacillus brevis Mm-6 isolated from breast milk. First, a 2-level Plackett-Burman design was applied to screen the bioprocess parameters that significantly influence the invertase production. The second optimization step was performed using fractional factorial design in order to optimize the amounts of variables have the highest positive significant effect on the invertase production. A maximal enzyme activity of 1399U/ml was more than five folds the activity obtained using the basal medium. Invertase was immobilized onto grafted alginate beads to improve the enzyme's stability. Immobilization process increased the operational temperature from 30 to 60°C compared to the free enzyme. The reusability test proved the durability of the grafted alginate beads for 15 cycles with retention of 100% of the immobilized enzyme activity to be more convenient for industrial uses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Neutralization of acidic drainage by Cryptococcus sp. T1 immobilized in alginate beads.

PubMed

Okai, Masahiko; Suwa, Chisato; Nagaoka, Shintaro; Obara, Nobuo; Mitsuya, Daisuke; Kurihara, Ayako; Ishida, Masami; Urano, Naoto

2017-11-01

We isolated Cryptococcus sp. T1 from Lake Tazawa's acidic water in Japan. Cryptococcus sp. T1 neutralized an acidic casamino acid solution (pH 3.0) and released ammonia from the casamino acids to aid the neutralization. The neutralization volume was estimated to be approximately 0.4 mL/h. The casamino acids' amino acids decreased (1.24→0.15 mM); ammonia increased (0.22→0.99 mM). We neutralized acidic drainage water (1 L) from a Tamagawa River neutralization plant, which was run through the column with the T1-immobilized alginate beads at a flow rate of 0.5 mL/min, and observed that the viscosity, particle size and amounts of the alginate beads affected the acidic drainage neutralization with an increase of the pH value from 5.26 to 6.61 in the last fraction. An increase in the Al concentration decreased Cryptococcus sp. T1's neutralization ability. After 48 h, the pH of acidic water with 50 mg/L Al was apparently lower than that without Al. Almost no pH increase was observed at 75 mg/L.

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

PubMed

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

2016-08-01

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

Novel characteristics of horseradish peroxidase immobilized onto the polyvinyl alcohol-alginate beads and its methyl orange degradation potential.

PubMed

Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M N; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

2017-12-01

Herein, we report the immobilization of in-house isolated horseradish peroxidase (HRP) from Armoracia rusticana with novel characteristics. The HRP was immobilized onto the self-fabricated polyvinyl alcohol-alginate (PVA-alginate) beads using sodium nitrate as a cross-linker. The PVA-alginate beads (2.0mm size) developed using 10% PVA and 1.5% sodium alginate showed maximal immobilization yield. The surface morphologies of the PVA-alginate (control) and immobilized-HRP were characterized by scanning electron microscopy (SEM). The immobilized-HRP retained 64.14% of its initial activity after 10 consecutive substrate-oxidation cycles as compared to the free counterpart. Simultaneously, the thermal stability of the immobilized-HRP was significantly enhanced as compared to the free HRP. The enzyme leakage (E L ) assay was performed by storing the immobilized-HRP in phosphate buffer solution for 30days. Evidently, the leakage of immobilized-HRP was recorded to be 6.98% and 14.82% after 15 and 30days of incubation, respectively. Finally, the immobilized-HRP was used for methyl orange (MO) dye degradation in a batch mode. A noticeable decline in spectral shift accompanied by no appearance of a new peak demonstrated the complete degradation of MO. The degraded fragments of MO were scrutinized by ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS). A plausible degradation pathway for MO was proposed based on the identified intermediates. In conclusion, the study portrays the PVA-alginate-immobilized-HRP as a cost-effective and industrially desirable green catalyst, for biotechnological at large and industrial in particular, especially for the treatment of textile dyes or dye-containing industrial waste effluents. Copyright © 2017 Elsevier B.V. All rights reserved.

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

DOE PAGES

Wang, Shuo; Jeon, Oju; Shankles, Peter G.; ...

2016-02-03

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

Alginate/cashew gum floating bead as a matrix for larvicide release.

PubMed

Paula, Haroldo C B; de Oliveira, Erick F; Abreu, Flávia O M S; de Paula, Regina C M

2012-08-01

A polymeric floating system composed of Alginate (ALG) and Cashew gum (CG), loaded with an essential oil (Lippia sidoides-Ls) was prepared by ionotropic gelation, characterized regarding its physical-chemistry properties and evaluated on its potential as a controlled release system. The influence of process parameters on the buoyancy, loading, swelling and in vitro and in vivo release kinetics, was investigated. Results showed that beads produced with carbonate and Ls at high level contents exhibit good floatability (up to 5 days) and loading capacity (15.2-23.8%). In vitro release data showed a Fickian diffusion profile and in vivo experiments showed that ALG-CG floating system presented a superior and prolonged larvicide effect, in comparison with non-floating ones, presenting larvae mortality values of 85% and 33%, respectively, after 48 h. These results indicate that ALG-CG floating beads loaded with Ls presented enhanced oil entrapment efficiency, excellent floating ability, and suitable larvicide release pattern. Copyright © 2012 Elsevier B.V. All rights reserved.

Floating capsules containing alginate-based beads of salbutamol sulfate: In vitro-in vivo evaluations.

PubMed

Malakar, Jadupati; Datta, Prabir Kumar; Purakayastha, Saikat Das; Dey, Sanjay; Nayak, Amit Kumar

2014-03-01

The present study deals with the development and evaluations of stomach-specific floating capsules containing salbutamol sulfate-loaded oil-entrapped alginate-based beads. Salbutamol sulfate-loaded oil-entrapped beads were prepared and capsulated within hard gelatin capsules (size 1). The effects of HPMC K4M and potato starch weight masses on drug encapsulation efficiency (DEE) of beads and cumulative drug release at 10h (R10 h) from capsules was analyzed by 3(2) factorial design. The optimization results indicate increasing of DEE in the oil-entrapped beads and decreasing R10 h from capsules with increment of HPMC K4M and potato starch weight masses. The optimized formulation showed DEE of 70.02 ± 3.16% and R10 h of 56.96 ± 2.92%. These capsules showed floatation over 6h and sustained drug release over 10h in gastric pH (1.2). In vivo X-ray imaging study of optimized floating capsules in rabbits showed stomach-specific gastroretention over a prolonged period. Copyright © 2013 Elsevier B.V. All rights reserved.

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

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2016-02-10

Alginate-carboxymethyl cellulose (CMC) gel beads were prepared in this study using sodium alginate (SA) and sodium CMC through blending and cross-linking. The specific surface area and aperture of the prepared SA-CMC gel beads were tested. The SA-CMC structure was characterized and analyzed via infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Static adsorption experiment demonstrated that Pb(II) adsorption of SA-CMC exceeded 99% under the optimized conditions. In addition, experiments conducted under the same experimental conditions showed that the lead ion removal efficiency of SA-CMC was significantly higher than that of conventional adsorbents. The Pb(II) adsorption process of SA-CMC followed the Langmuir adsorption isotherm, and the dynamic adsorption model could be described through a pseudo-second-order rate equation. Pb(II) removal mechanisms of SA-CMC, including physical, chemical, and electrostatic adsorptions, were discussed based on microstructure analysis and adsorption kinetics. Chemical adsorption was the main adsorption method among these mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Alginate Beads as Synthetic Inoculant Carriers for Slow Release of Bacteria That Affect Plant Growth †‡

PubMed Central

Bashan, Yoav

1986-01-01

Uniform synthetic beads were developed as carriers for the bacterial inoculation of plants. The beads are made of sodium alginate and skim milk and contain a large reservoir of bacterial culture which releases the bacteria at a slow and constant rate. The beads are biodegradable and produce no environmental pollution. The strength of the beads, the rate of bacterial release, and the time of their survival in the soil can be controlled by several hardening treatments. The final product, lyophilized beads, is simple to use and is applied to the seeds concomitantly with sowing. The released bacteria are available for root colonization immediately at seed germination. Dry beads containing bacteria can be stored at ambient temperature over a long period without loss of bacterial content; storage requires a limited space, and the quality control of a number of bacteria in the bead is simple. The level of plant inoculation with beads was similar to that with previously used peat inoculants, but the former method yielded more consistent results, as the frequency of inoculated plants was much higher. The former method provides a different approach for inoculation of plants with beneficial rhizosphere bacteria. Images PMID:16347055

Removal of toxic metals from leachates from hazardous solid wastes and reduction of toxicity to microtox by the use of calcium alginate beads containing humic acid.

PubMed

Pandey, Ashok K; Pandey, Shri Dhar; Misra, Virendra

2002-06-01

Improper disposal of hazardous wastes can lead to release of potentially harmful substances through leaching such as heavy metals, which ultimately contaminate soil, sediment surface water, and groundwater through runoff. To remove these toxic metals and avoid any adverse effect on the ecosystem, a novel approach involving calcium alginate (CA) beads containing humic acid (HA) was used. For this, 10% leachates of the waste obtained from two major industrial units with electroplating processess were prepared at neutral pH and analyzed by atomic absorption spectrophotometry (AAS). Both leachates contained Cd, Cu, Cr, Ni, Mn, Fe, and Zn. The concentrations of Ni, Mn, Fe, and Zn in the waste were found to be significant. The leachates analyzed were passed through columns packed with calcium alginate beads with or without humic acid. The concentrations of various metals in beads and in different fractions collected after adsorption were measured. Data recorded indicate that calcium alginate beads containing humic acids are more efficient in removal of all metals in substantial amounts from the two leachates. Along with removal of metals, this process led to considerable detoxification of the leachates as tested by Microtox assay, indicated by earlier protection and higher EC(50). The significance of the results in relation to removal of toxic metals by beads containing humic acid is discussed. (c) 2002 Elsevier Science (USA).

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

PubMed

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

2012-01-01

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 input 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 that of 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.

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

PubMed Central

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

2012-01-01

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 input 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 that of 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. PMID:24198865

Controlled ice nucleation using freeze-dried Pseudomonas syringae encapsulated in alginate beads.

PubMed

Weng, Lindong; Tessier, Shannon N; Swei, Anisa; Stott, Shannon L; Toner, Mehmet

2017-04-01

The control of ice nucleation is of fundamental significance in many process technologies related to food and pharmaceutical science and cryobiology. Mechanical perturbation, electromagnetic fields and ice-nucleating agents (INAs) have been known to induce ice nucleation in a controlled manner. But these ice-nucleating methods may suffer from cumbersome manual operations, safety concerns of external fields, and biocompatibility and recovery issues of INA particles, especially when used in living systems. Given the automatic ice-seeding nature of INAs, a promising solution to overcome some of the above limitations is to engineer a biocomposite that accommodates the INA particles but minimizes their interactions with biologics, as well as enabling the recovery of used particles. In this study, freeze-dried Pseudomonas syringae, a model ice-nucleating agent, was encapsulated into microliter-sized alginate beads. We evaluated the performance of the bacterial hydrogel beads to initiate ice nucleation in water and aqueous glycerol solution by investigating factors including the size and number of the beads and the local concentration of INA particles. In the aqueous sample of a fixed volume, the total mass of the INA particles (m) was found to be the governing parameter that is solely responsible for determining the ice nucleation performance of the bacterial hydrogel beads. The freezing temperature has a strong positive linear correlation with log 10 m. The findings in this study provide an effective, predictable approach to control ice nucleation, which can improve the outcome and standardization of many ice-assisted process technologies. Copyright © 2017 Elsevier Inc. All rights reserved.

Statistical optimization of arsenic biosorption by microbial enzyme via Ca-alginate beads.

PubMed

Banerjee, Suchetana; Banerjee, Anindita; Sarkar, Priyabrata

2018-04-16

Bioremediation of arsenic using green technology via microbial enzymes has attracted scientists due to its simplicity and cost effectiveness. Statistical optimization of arsenate bioremediation was conducted by the enzyme arsenate reductase extracted from arsenic tolerant bacterium Pseudomonas alcaligenes. Response surface methodology based on Box-Behnken design matrix was performed to determine the optimal operational conditions of a multivariable system and their interactive effects on the bioremediation process. The highest biosorptive activity of 96.2 µg gm -1 of beads was achieved under optimized conditions (pH = 7.0; As (V) concentration = 1000 ppb; time = 2 h). SEM analysis showed the morphological changes on the surface of enzyme immobilized gluteraldehyde crosslinked Ca-alginate beads. The immobilized enzyme retained its activity for 8 cycles. ANOVA with a high correlation coefficient (R 2 > 0.99) and lower "Prob > F"value (<0.0001) corroborated the second-order polynomial model for the biosorption process. This study on the adsorptive removal of As (V) by enzyme-loaded biosorbent revealed a possible way of its application in large scale treatment of As (V)-contaminated water bodies.

Polygalacturonase production by calcium alginate immobilized Enterobacter aerogenes NBO2 cells.

PubMed

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

2015-03-01

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

Incorporation of beads into oral films for buccal and oral delivery of bioactive molecules.

PubMed

Castro, Pedro M; Sousa, Flávia; Magalhães, Rui; Ruiz-Henestrosa, Victor Manuel Pizones; Pilosof, Ana M R; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela E

2018-08-15

The association of alginate beads and guar-gum films in a single delivery system was idealized to promote a more effective buccal and oral delivery of bioactive molecules. A response surface method (experimental design approach) was performed to obtain optimal formulations of alginate beads to be incorporated into guar gum oral films as combined buccal and oral delivery systems for caffeine delivery. The combined formulation was further characterized regarding physicochemical properties, drug release, cell viability and buccal permeability. Beads average size, determined by dynamic light scattering (DLS), was of 3.37 ± 6.36 μm. Film thickness was set to 62 μm. Scanning electron microscopy micrographs revealed that beads were evenly distributed onto the film matrix and beads size was in accordance to data obtained from DLS analysis. Evaluation of Fourier-transform infrared spectra did not indicate the formation of new covalent bonds between the matrix of guar-gum films, alginate beads and caffeine. In vitro release assays by dialysis membrane allowed understanding that the combination of guar-gum films and alginate beads assure a slower release of caffeine when compared with the delivery profile of free caffeine from alginate beads or guar-gum films alone. MTT assay, performed on human buccal carcinoma TR146 cell line, allowed concluding that neither guar-gum film, alginate beads nor guar-gum film incorporated into alginate beads significantly compromised cell viability after 12 h of exposure. As demonstrated by in vitro permeability assay using TR146 human buccal carcinoma cell lines, combination of guar-gum films and alginate beads also promoted a slower release and, thus, lower apparent permeability (1.15E-05 ± 3.50E-06) than for caffeine solution (2.68E-05 ± 7.30E-06), guar-gum film (3.12E-05 ± 4.70E-06) or alginate beads (2.01E-05 ± 3.90E-06). The conjugation of alginate beads within an orodispersible film matrix represents an

Chitosan cocrystals embedded alginate beads for enhancing the solubility and bioavailability of aceclofenac.

PubMed

Ganesh, Mani; Jeon, Ung Jin; Ubaidulla, Udhumansha; Hemalatha, Pushparaj; Saravanakumar, Arthanari; Peng, Mei Mei; Jang, Hyun Tae

2015-03-01

Enhanced oral bioavailability of aceclofenac has been achieved using chitosan cocrystals of aceclofenac and its entrapment into alginate matrix a super saturated drug delivery system (SDDS). Prepared SDDS were evaluated by various physiochemical and pharmacological methods. The result revealed that the primary cocrystals enhanced the solubility of the drug and the thick gelled polymer matrix that formed from swelling of calcium alginate beads makes it to release the drug in continuous and sustained manner by supersaturated drug diffusion. The Cmax, Tmax and relative bioavailability for aceclofenac cocrystal and aceclofenac SDDS were 2.06±0.42 μg/ml, 1 h, 159.72±10.84 and 2.01 μg/ml, 1 h, 352.76±12.91, respectively. Anti-inflammatory activity of aceclofenac was significantly improved with the SDDS. With respect to the results, it revealed that the SDDS described herein might be a promising tool for the oral sustained release of aceclofenac and likely for that of various other poorly soluble drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

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

Calcium-alginate/carbon nanotubes/TiO2 composite beads for removal of bisphenol A.

PubMed

Hartono, Maria R; Kushmaro, Ariel; Marks, Robert S; Chen, Xiaodong

2016-10-01

In this study, composite calcium-alginate/carbon nanotubes/TiO 2 beads were prepared and tested for their potential in the removal of bisphenol A (BPA) from aqueous solutions. The removal traits were inspected using a fixed-bed sorption column. By varying parameters such as bed height (15-20 cm), flow rate (2.0-6.0 mL.min -1 ) and inlet BPA concentration (10-30 mg.L -1 ) we assessed the removal capacity of these composites. The highest sorption capacity of 5.46 mg.g -1 was achieved at 10 mg.L -1 BPA concentration, 2.0 mL.min -1 flow rate and 20 cm bed height at saturation. Adams-Bohart, Yoon-Nelson and Dose-Response isotherm models were applied to evaluate the performance of the column at different inlet concentrations. The experimental data satisfactorily fit the Dose-Response model with high correlation (r 2 > 0.97) across the breakthrough curve. Regeneration of the used adsorbent beads were performed by immersion in the desorption solvent followed by light irradiation. It was postulated that inclusion of TiO 2 facilitates the desorbed pollutant degradation from the used adsorbent beads.

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. Copyright © 2014 Elsevier B.V. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xiao-xi; Liu, Chang; University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049

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 expressionmore » 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.« less

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

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

PubMed

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

2012-01-01

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

Effect of lecithin and starch on alginate-encapsulated probiotic bacteria.

PubMed

Donthidi, A R; Tester, R F; Aidoo, K E

2010-01-01

The effect of lecithin and starch on viability of alginate encapsulated probiotics was determined at different temperatures. Probiotic organisms (1% v/v>10Log CFU ml(-1)) were encapsulated using alginate (2% w/v), gelatinized starches (2% w/v) and lecithin (0-4% w/v) and stored in sealed containers at 4, 23 and 37 degrees C (to simulate shelf storage conditions). Incorporation of lecithin improved the entrapment efficiency (p < 0.05) and the viability of encapsulated bacteria (p = 0.02). Encapsulated Lactobacillus, Bifidobacterium species and Lactococcus lactis in lecithin containing freeze-dried beads had good survival stability (above 6Log CFU ml(-1)) at 23 degrees C for 12 weeks. The bacteria in the beads showed 6Log survival by the end of 2 weeks at 37 degrees C. Encapsulated L. casei in the alginate beads containing lecithin were also more stable in the yoghurt than the beads without lecithin. SEM analysis of the beads showed an irregular surface for the beads without lecithin.

Three-dimensional alginate spheroid culture system of murine osteosarcoma.

PubMed

Akeda, Koji; Nishimura, Akinobu; Satonaka, Haruhiko; Shintani, Ken; Kusuzaki, Katsuyuki; Matsumine, Akihiko; Kasai, Yuichi; Masuda, Koichi; Uchida, Atsumasa

2009-11-01

Osteosarcoma (OS) is the most common primary malignant tumor of the bone and often forms pulmonary metastases, which are the most important prognostic factor. For further elucidation of the mechanism underlying the progression and metastasis of human OS, a culture system mimicking the microenvironment of the tumor in vivo is needed. We report a novel three-dimensional (3D) alginate spheroid culture system of murine osteosarcoma. Two different metastatic clones, the parental Dunn and its derivative line LM8, which has a higher metastatic potential to the lungs, were encapsulated in alginate beads to develop the 3D culture system. The beads containing murine OS cells were also transplanted into mice to determine their metastatic potential in vivo. In this culture system, murine OS cells encapsulated in alginate beads were able to grow in a 3D structure with cells detaching from the alginate environment. The number of detaching cells was higher in the LM8 cell line than the Dunn cell line. In the in vivo alginate bead transplantation model, the rate of pulmonary metastasis was higher with LM8 cells compared with that of Dunn cells. The cell characteristics and kinetics in this culture system closely reflect the original malignant potential of the cells in vivo.

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.

Controlled Release of 5-Fluorouracil from Alginate Beads Encapsulated in 3D Printed pH-Responsive Solid Dosage Forms.

PubMed

Gioumouxouzis, Christos I; Chatzitaki, Aikaterini-Theodora; Karavasili, Christina; Katsamenis, Orestis L; Tzetzis, Dimitrios; Mystiridou, Emmanouela; Bouropoulos, Nikolaos; Fatouros, Dimitrios G

2018-06-14

Three-dimensional printing is being steadily deployed as manufacturing technology for the development of personalized pharmaceutical dosage forms. In the present study, we developed a hollow pH-responsive 3D printed tablet encapsulating drug loaded non-coated and chitosan-coated alginate beads for the targeted colonic delivery of 5-fluorouracil (5-FU). A mixture of Eudragit® L100-55 and Eudragit® S100 was fabricated by means of hot-melt extrusion (HME) and the produced filaments were printed utilizing a fused deposition modeling (FDM) 3D printer to form the pH-responsive layer of the tablet with the rest comprising of a water-insoluble poly-lactic acid (PLA) layer. The filaments and alginate particles were characterized for their physicochemical properties (thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction), their surface topography was visualized by scanning electron microscopy and the filaments' mechanical properties were assessed by instrumented indentation testing and tensile testing. The optimized filament formulation was 3D printed and the structural integrity of the hollow tablet in increasing pH media (pH 1.2 to pH 7.4) was assessed by means of time-lapsed microfocus computed tomography (μCT). In vitro release studies demonstrated controlled release of 5-FU from the alginate beads encapsulated within the hollow pH-sensitive tablet matrix at pH values corresponding to the colonic environment (pH 7.4). The present study highlights the potential of additive manufacturing in fabricating controlled-release dosage forms rendering them pertinent formulations for further in vivo evaluation.

Systematic study of alginate-based microcapsules by micropipette aspiration and confocal fluorescence microscopy.

PubMed

Kleinberger, Rachelle M; Burke, Nicholas A D; Dalnoki-Veress, Kari; Stöver, Harald D H

2013-10-01

Micropipette aspiration and confocal fluorescence microscopy were used to study the structure and mechanical properties of calcium alginate hydrogel beads (A beads), as well as A beads that were additionally coated with poly-L-lysine (P) and sodium alginate (A) to form, respectively, AP and APA hydrogels. A beads were found to continue curing for up to 500 h during storage in saline, due to residual calcium chloride carried over from the gelling bath. In subsequent saline washes, micropipette aspiration proved to be a sensitive indicator of gel weakening and calcium loss. Aspiration tests were used to compare capsule stiffness before and after citrate extraction of calcium. They showed that the initial gel strength is largely due to the calcium alginate gel cores, while the long term strength is solely due to the poly-L-lysine-alginate polyelectrolyte complex (PEC) shells. Confocal fluorescence microscopy showed that calcium chloride exposure after PLL deposition led to PLL redistribution into the hydrogel bead, resulting in thicker but more diffuse and weaker PEC shells. Adding a final alginate coating to form APA capsules did not significantly change the PEC membrane thickness and stiffness, but did speed the loss of calcium from the bead core. © 2013.

Encapsulation of Autoinducer Sensing Reporter Bacteria in Reinforced Alginate-Based Microbeads.

PubMed

Li, Ping; Müller, Mareike; Chang, Matthew Wook; Frettlöh, Martin; Schönherr, Holger

2017-07-12

Quorum sensing, in which bacteria communities use signaling molecules for inter- and intracellular communication, has been intensively studied in recent decades. In order to fabricate highly sensitive easy-to-handle point of care biosensors that detect quorum sensing molecules, we have developed, as is reported here, reporter bacteria loaded alginate-methacrylate (alginate-MA) hydrogel beads. The alginate-MA beads, which were obtained by electrostatic extrusion, were reinforced by photo-cross-linking to increase stability and thereby to reduce bacteria leaching. In these beads the genetically engineered fluorescent reporter bacterium Escherichia coli pTetR-LasR-pLuxR-GFP (E. coli pLuxR-GFP) was encapsulated, which responds to the autoinducer N-(3-oxododecanoyl)homoserine lactone secreted by Pseudomonas aeruginosa. After encapsulation in alginate-MA hydrogel beads with diameters in the range of 100-300 μm that were produced by an electrostatic extrusion method and rapid photo-cross-linking, the E. coli pLuxR-GFP were found to possess a high degree of viability and sensing activity. The encapsulated bacteria could proliferate inside the hydrogel beads, when exposed to bacteria culture medium. In media containing the autoinducer N-(3-oxododecanoyl)homoserine lactone, the encapsulated reporter bacteria responded with a strong fluorescence signal due to an increased green fluorescent protein (GFP) expression. A prototype dipstick type sensor developed here underlines the potential of encapsulation of viable and functional reporter bacteria inside reinforced alginate-methacrylate hydrogel beads for whole cell sensors for bacteria detection.

Immobilization of naringinase in PVA-alginate matrix using an innovative technique.

PubMed

Nunes, Mário A P; Vila-Real, Hélder; Fernandes, Pedro C B; Ribeiro, Maria H L

2010-04-01

A synthetic polymer, polyvinyl alcohol (PVA), a cheap and nontoxic synthetic polymer to organism, has been ascribed for biocatalyst immobilization. In this work PVA-alginate beads were developed with thermal, mechanical, and chemical stability to high temperatures (<80 degrees C). The combination of alginate and bead treatment with sodium sulfate not only prevented agglomeration but produced beads of high gel strength and conferred enzyme protection from inactivation by boric acid. Naringinase from Penicillium decumbens was immobilized in PVA (10%)-alginate beads with three different sizes (1-3 mm), at three different alginate concentrations (0.2-1.0%), and these features were investigated in terms of swelling ratio within the beads, enzyme activity, and immobilization yield during hydrolysis of naringin. The pH and temperature optimum were 4.0 and 70 degrees C for the PVA-alginate-immobilized naringinase. The highest naringinase activity yield in PVA (10%)-alginate (1%) beads of 2 mm was 80%, at pH 4.0 and 70 degrees C. The Michaelis constant (K(Mapp)) and the maximum reaction velocity (V(maxapp)) were evaluated for both free (K(Mapp) = 0.233 mM; V(maxapp) = 0.13 mM min(-1)) and immobilized naringinase (K(Mapp) = 0.349 mM; V(maxapp) = 0.08 mM min(-1)). The residual activity of the immobilized enzyme was followed in eight consecutive batch runs with a retention activity of 70%. After 6 weeks, upon storage in acetate buffer pH 4 at 4 degrees C, the immobilized biocatalyst retained 90% of the initial activity. These promising results are illustrative of the potential of this immobilization strategy for the system evaluated and suggest that its application may be effectively performed for the entrapment of other biocatalysts.

Alginate Microcapsules Incorporating Hyaluronic Acid Recreate Closer in Vivo Environment for Mesenchymal Stem Cells.

PubMed

Cañibano-Hernández, Alberto; Saenz Del Burgo, Laura; Espona-Noguera, Albert; Orive, Gorka; Hernández, Rosa M; Ciriza, Jesús; Pedraz, Jose Luis

2017-07-03

The potential clinical application of alginate cell microencapsulation has advanced enormously during the past decade. However, the 3D environment created by alginate beads does not mimic the natural extracellular matrix surrounding cells in vivo, responsible of cell survival and functionality. As one of the most frequent macromolecules present in the extracellular matrix is hyaluronic acid, we have formed hybrid beads with alginate and hyaluronic acid recreating a closer in vivo cell environment. Our results show that 1% alginate-0.25% hyaluronic acid microcapsules retain 1.5% alginate physicochemical properties. Moreover, mesenchymal stem cells encapsulated in these hybrid beads show enhanced viability therapeutic protein release and mesenchymal stem cells' potential to differentiate into chondrogenic lineage. Although future studies with additional proteins need to be done in order to approach even more the extracellular matrix features, we have shown that hyaluronic acid protects alginate encapsulated mesenchymal stem cells by providing a niche-like environment and remaining them competent as a sustainable drug delivery system.

Biochemical consequences of alginate encapsulation: a NMR study of insulin-secreting cells.

PubMed

Simpson, Nicholas E; Grant, Samuel C; Gustavsson, Lenita; Peltonen, Vilje-Mia; Blackband, Stephen J; Constantinidis, Ioannis

2006-04-01

In this study we explore the biochemical consequences of alginate encapsulation on betaTC3 cells. (13)C NMR spectroscopy and isotopomer analysis were used to investigate the effects of encapsulation on several enzymatic processes associated with the TCA cycle. Our data show statistically significant differences in various enzymatic fluxes related to the TCA cycle and insulin secretion between monolayer and alginate-encapsulated cultures. The principal cause for these effects was the process of trypsinization. Embedding the trypsinized cells in alginate beads did not have a compounded effect on the enzymatic fluxes of entrapped cells. However, an additional small but statistically significant decrease in insulin secretion was measured in encapsulated cells. Finally, differences in either enzymatic fluxes or glucose consumption as a function of bead diameter were not observed. However, differences in T(2), assessed by (1)H NMR microimaging, were observed as a function of bead diameter, suggesting that smaller beads became more organized with time in culture, while larger beads displayed a looser organization.

Enhanced biosorption of transition metals by living Chlorella vulgaris immobilized in Ca-alginate beads.

PubMed

Ahmad, Ashfaq; Bhat, A H; Buang, Azizul

2018-02-01

In this study freely suspended and Ca-alginate immobilized C. vulgaris cells were used for the biosorption of Fe(II), Mn(II), and Zn(II) ions, from the aqueous solution. Experimental data showed that biosorption capacity of algal cells was strongly dependent on the operational condition such as pH, initial metal ions concentration, dosages, contact time and temperature. The maximum biosorption of Fe(II) 43.43, Mn(II) 40.98 and Zn(II) 37.43 mg/g was achieved with Ca-alginate immobilized algal cells at optimum pH of 6.0, algal cells dosage 0.6 g/L, and contact time of 450 min at room temperature. The biosorption efficiency of freely suspended and immobilized C. vulgaris cells for heavy metals removal from the industrial wastewater was validated. Modeling of biosorption kinetics showed good agreements with pseudo-second-order. Langmuir and D-R isotherm models exhibited the best fit of experimental data. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) revealed that the biosorption of considered metal ions was feasible, spontaneous and exothermic at 25-45°C. The SEM showed porous morphology which greatly helps in the biosorption of heavy metals. The Fourier transform infrared spectrophotometer (FTIR) and X-rays Photon Spectroscopy (XPS) data spectra indicated that the functional groups predominately involved in the biosorption were C-N, -OH, COO-, -CH, C=C, C=S and -C-. These results shows that immobilized algal cells in alginate beads could potentially enhance the biosorption of considered metal ions than freely suspended cells. Furthermore, the biosorbent has significantly removed heavy metals from industrial wastewater at the optimized condition.

Design, characterisation and application of alginate-based encapsulated pig liver esterase.

PubMed

Pauly, Jan; Gröger, Harald; Patel, Anant V

2018-06-05

Encapsulation of hydrolases in biopolymer-based hydrogels often suffers from low activities and encapsulation efficiencies along with high leaching and unsatisfactory recycling properties. Exemplified for the encapsulation of pig liver esterase the coating of alginate and chitosan beads have been studied by creating various biopolymer hydrogel beads. Enzyme activity and encapsulation efficiency were notably enhanced by chitosan coating of alginate beads while leaching remained nearly unchanged. This was caused by the enzymatic reaction acidifying the matrix, which increased enzyme retention through enhanced electrostatic enzyme-alginate interaction but decreased activity through enzyme deactivation. A practical and ready-to-use method for visualising pH in beads during reaction by co-encapsulation of a conventional pH indicator was also found. Our method proves that pH control inside the beads can only be realised by buffering. The resulting beads provided a specific activity of 0.267 μmol ∙ min -1 ∙ mg -1 , effectiveness factor 0.88, encapsulation efficiency of 88%, 5% leaching and good recycling properties. This work will contribute towards better understanding and application of encapsulated hydrolases for enzymatic syntheses. Copyright © 2018 Elsevier B.V. All rights reserved.

Porous synthetic hectorite clay-alginate composite beads for effective adsorption of methylene blue dye from aqueous solution.

PubMed

Pawar, Radheshyam R; Lalhmunsiama; Gupta, Prabuddha; Sawant, Sandesh Y; Shahmoradi, B; Lee, Seung-Mok

2018-07-15

The present study deals with the preparation and characterization of mesoporous synthetic hectorite (MSH) clay which further encapsulated with Na-alginate for the preparation of mesoporous synthetic hectorite-alginate beads (MSH-AB) where Ca 2+ act as a cross-linking agent. The detail characterization of MSH and MSH-AB were carried out by various physicochemical techniques. The thermogravimetric analysis study showed better thermal stability results for MSH-AB. The textural properties results of MSH and MSH-AB showed the high surface area 468, 205m 2 /g, and the pore volume of 0.34, 0.29cm 3 /g respectively. The applicability of powder MSH and MSH-AB in wet (W) and dry (D) forms were assessed for the removal of cationic dye, methylene blue (MB) by optimizing various batch adsorption parameters. The Langmuir monolayer adsorption capacity obtained for MSH-AB-W showed significant high adsorption efficacy (i.e., 785.45mgMB/g) compared to the MSH-AB-D (357.14mgMB/g) and powder MSH materials (196.00mgMB/g). The adsorption isotherm studies showed that the Langmuir isotherm model was best suitable for MSH, whereas the Freundlich model was utilised to describe the adsorption behavior of organized hydrogel composite beads. The pseudo-second-order kinetics model was observed best for MB sorption onto MSH, whereas pseudo-first order useful to describe the kinetic behavior of MSH-AB. The regeneration experimental results revealed that MSH-AB-W could be recycled more than six cycles with high MB removal efficiency. Furthermore, the adsorption property of the MSH-AB-W was examined for the binary mixture of MB with other dye solutions such as Methyl Red (MR), Methyl Orange (MO), Alizarine Yellow (AY), and Remazol Brilliant Blue (RBB) to evaluate the selective adsorption efficiency. The MSH composite beads were found potentially suitable as an efficient, selective and recyclable adsorbent for the removal of MB from the aqueous solutions. Copyright © 2018 Elsevier B.V. All rights

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

PubMed

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

2015-03-01

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

Alginate microencapsulation technology for the percutaneous delivery of adipose-derived stem cells.

PubMed

Moyer, Hunter R; Kinney, Ramsey C; Singh, Kimberly A; Williams, Joseph K; Schwartz, Zvi; Boyan, Barbara D

2010-11-01

Autologous fat is the ideal soft-tissue filler; however, its widespread application is limited because of variable clinical results and poor survival. Engineered fillers have the potential to maximize survival. Alginate is a hydrogel copolymer that can be engineered into spheres of <200 μm, thus facilitating mass transfer, allowing for subcutaneous injection, and protecting cells from shearing forces. Alginate powder was dissolved in saline, and adipose-derived stem cells (ADSCs) were encapsulated (1 million cells/mL) in alginate using an electrostatic bead generator. To assess effects of injection on cell viability, microspheres containing ADSCs were separated into 2 groups: the control group was decanted into culture wells and the injection group was mixed with basal media and injected through a 21-gauge needle into culture wells. Microbeads were cultured for 3 weeks, and cell number and viability were measured weekly using electron and confocal microscopy. To assess effects of percutaneous injection in vivo, twenty-four male nude mice were randomly separated into 2 groups and injected with either empty microcapsules or ADSC-laden microcapsules. Mice were harvested at 1 and 3 months, and the implants were examined microscopically to assess bead and cell viability. A flow rate of 5 mL/h and an electrostatic potential of 7 kV produced viable ADSC-laden microbeads of <200 μm. There were no differences in bead morphology and ADSC viability between microcapsules placed versus injected into tissue culture plates for up to 3 weeks. Microspheres implanted in a nude mouse model show durability up to 3 months with a host response around each individual sphere. ADSCs remained viable and showed signs of mitosis. ADSCs can be readily cultured, encapsulated, and injected in alginate microspheres. Stem cells suspended in alginate microspheres survive in vivo and are seen to replicate in vitro.

Ag2O/sodium alginate-reduced graphene oxide aerogel beads for efficient visible light driven photocatalysis

NASA Astrophysics Data System (ADS)

Ma, Yuhua; Wang, Jiajia; Xu, Shimei; Feng, Shun; Wang, Jide

2018-02-01

In this work, one facile and green method was developed to resolve the instinct defects of pure Ag2O and increase visible-light photocatalytic activity of Ag2O-based catalyst. In which, Ag2O was immobilized in sodium alginate-reduced graphene oxide (ALG-rGO) aerogel beads. The as-prepared aerogel beads showed a well-defined interconnected three-dimensional porous network and displayed the highest photocatalytic activity with a mass ratio of 40:1 (ALG:rGO). For the degradation of cationic Rhodamine B (RhB) and anionic dye Orange II (OII) dyes, rate constants were 1.95 × 10-2 min-1 and 4.13 × 10-2 min-1, which were 2.4 and 3.1 times higher than those of Ag2O/ALG aerogel beads, respectively. The further studies demonstrated that presence of rGO can effectively decrease the size of Ag2O, extend photoresponding range (UV to near-infrared light spectrum), speed-up separate photogenerated electrons and holes, retard charge recombination, and prolong electron lifetime and effective carrier diffusion length. The potential mechanism for RhB and OII degrading was expounded, and main active species in the degradation reactions of dyes were investigated by a series of trapping experiments. It offered a promising photocatalyst to purify the wastewater, and provided a sophisticated understanding of the pivotal role rGO acting in photocatalysis.

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

PubMed Central

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

2014-01-01

Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedure and cell concentration do not affect the diameter of alginate beads, ii) encapsulation of high cell numbers (up to 10×106 cells/ml) can be performed in alginate beads utilizing high voltage and iii) high voltage (15–30 kV) does not alter the viability, proliferation and differentiation capacity of MSCs post-encapsulation compared with alginate encapsulated cells produced by the traditional air-flow method. The consistent results were obtained over the period of 7 days of encapsulated MSCs culture and after cryopreservation utilizing a slow cooling procedure (1 K/min). The results of this work show that high voltage encapsulation can further be maximized to develop cell-based therapies with alginate beads in a non-human primate model towards human application. PMID:25259731

Graphene oxide/alginate beads as adsorbents: Influence of the load and the drying method on their physicochemical-mechanical properties and adsorptive performance.

PubMed

Platero, Emiliano; Fernandez, Maria Emilia; Bonelli, Pablo Ricardo; Cukierman, Ana Lea

2017-04-01

Graphene oxide/alginate beads were prepared from lab-synthesized graphene oxide, varying its content within the beads (0.05, 0.125, and 0.25wt.%). Ethanol-drying and lyophilization were compared as drying methods to obtain suitable adsorbents which were later tested to the removal of a model organic molecule (methylene blue). The morphological and textural properties of all the beads were characterized by scanning electron microscopy and N 2 adsorption/desorption isotherms at -196°C, respectively. Limited porosity was obtained for all cases (S BET <60m 2 /g). Uniaxial compression tests were performed to assess the mechanical properties of the beads. Ethanol-dried ones exhibited higher Young's elasticity modulus (E=192kPa) than the lyophilized samples (twice at 0.25wt.% graphene oxide loading), which disclosed breakage points at lower deformation percentages. Adsorption experiments were conducted and dye adsorption isotherms were obtained for the beads with the best removal performance. The experimental data were better fitted by the Langmuir model. The highest maximum adsorption capacity (4.25mmol/g) was obtained for the lyophilized beads with the highest graphene oxide content. Mechanical properties were found to be affected also by the dye adsorption. Copyright © 2016 Elsevier Inc. All rights reserved.

Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

PubMed

Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

2018-01-01

Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alginate beads containing water treatment residuals for arsenic removal from water-formation and adsorption studies.

PubMed

Ociński, Daniel; Jacukowicz-Sobala, Irena; Kociołek-Balawejder, Elżbieta

2016-12-01

Water treatment residuals (WTRs) produced in large quantities during deironing and demanganization of infiltration water, due to high content of iron and manganese oxides, exhibit excellent sorptive properties toward arsenate and arsenite. Nonetheless, since they consist of microparticles, their practical use as an adsorbent is limited by difficulties with separation from treated solutions. The aim of this study was entrapment of chemically pretreated WTR into calcium alginate polymer and examination of sorptive properties of the obtained composite sorbent toward As(III) and As(V). Different products were formed varying in WTR content as well as in density of alginate matrix. In order to determine the key parameters of the adsorption process, both equilibrium and kinetic studies were conducted. The best properties were exhibited by a sorbent containing 5 % residuals, formed in alginate solution with a concentration of 1 %. In slightly acidic conditions (pH 4.5), its maximum sorption capacity was 3.4 and 2.9 mg g -1 for As(III) and As(V), respectively. At neutral pH, the adsorption effectiveness decreased to 3.3 mg As g -1 for arsenites and to 0.7 mg As g -1 for arsenates. The presence of carboxylic groups in polymer chains impeded in neutral conditions the diffusion of anions into sorbent beads; therefore, the main rate-limiting step of the adsorption, mainly in the case of arsenates, was intraparticle diffusion. The optimal condition for simultaneous removal of arsenates and arsenites from water by means of the obtained composite sorbent is slightly acidic pH, ensuring similar adsorption effectiveness for both arsenic species.

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 (K 2) 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

Removal of Lead from Water Using Calcium Alginate Beads Doped with Hydrazine Sulphate-Activated Red Mud as Adsorbent

PubMed Central

2017-01-01

Calcium alginate beads doped with hydrazine sulphate-treated red mud are investigated as adsorbent for extracting lead ions from water using batch methods of extraction. Different extraction conditions are optimised for maximum lead extraction. Substantial amount of lead is removed, and the adsorption ability is found to be 138.6 mg/g. Surface characterization using FTIR, EDX, and FESEM confirms that lead is “onto” the surface of the adsorbent. Thermodynamic parameters, adsorption isotherms, and kinetics of adsorption are analysed. Adsorption is “physisorption” in nature and spontaneous. The adsorbent developed can be regenerated using 0.1 M HCl. Thus regenerated adsorbent can be used as the adsorbent for further removal of lead at least 10 times, and this enables the complete removal of lead from water by repetitive use of the regenerated adsorbent. The beads facilitate the easy filtration. The methodology developed is successfully applied for removing lead from industrial waste waters. PMID:29527385

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.

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.

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

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

PubMed

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

2013-11-15

In this study, Fe(0)-Fe3O4 nanocomposites embedded polyvinyl alcohol (PVA)/sodium alginate (SA) beads were synthesized, which exhibited an excellent physical properties and catalytic reactivity, and a robust performance of post-separation (complete separation using a simple grille) and reusability (efficiency of 69.8% after four runs) in Cr(VI) removal. 5.0 wt% PVA with 1.5 wt% SA was the optimal proportion for beads molding, and the followed acidification and reduction treatments were critical to ensure high mechanical strength and high Cr(VI) removal ability of beads. Effects of Fe(0) and Fe3O4 mass fraction, initial pH and Cr(VI) concentration on final removal efficiency were also evaluated. Merely 0.075 wt% Fe(0) together with 0.30 wt% Fe3O4 was sufficient to deal with 20 mg L(-1) Cr(VI) solution. The efficiency decreased from 100 to 79.5% as initial Cr(VI) increased from 5 to 40 mg L(-1), while from 99.3 to 76.3% with increasing pH from 3.0 to 11.0. This work provides a practical and high-efficient method for heavy metal removal from water body, and simultaneously solves the problems in stabilization, separation and regeneration of Fe(0) nanoparticles. Copyright © 2013 Elsevier B.V. All rights reserved.

Encapsulation optimization of lemon balm antioxidants in calcium alginate hydrogels.

PubMed

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

2016-11-01

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

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

PubMed

Prabakaran, G; Hoti, S L

2008-08-01

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

Copper and nitrophenol pollutants removal by Na-montmorillonite/alginate microcapsules.

PubMed

Ely, Abdellahi; Baudu, Michel; Basly, Jean-Philippe; Kankou, Mohamed Ould Sid'Ahmed Ould

2009-11-15

The use of renewable bioresources allows the development of low cost adsorbents that are versatile. In the present paper, the affinity and the removal capacity of montmorillonite/alginate microcapsules for a hydrophobic organic pollutant (4-nitrophenol) and an inorganic pollutant (copper) were evaluated. The physicochemical processes through sorption and kinetic experiments under different ratios of montmorillonite vs. alginate and initial contaminant concentrations were investigated. The total weight loss and diameter decrease during the drying process were 90-96% and 64%, respectively. A significant decrease in beads diameter, related to water elimination, has been observed during the first 24h. Structural modifications that occur during the drying process were evaluated using thermal analysis. From correlation coefficients, the second-order equation depicts properly the adsorption of copper by the microbeads adsorption capacity increases to saturation with time; 3 and 6h were needed to reach equilibrium on wet and dry mixed microcapsules. The pseudo-second order model properly depicts the adsorption process of 4-NP onto Na-mont and (Na-mont/SA) mixed microcapsules but failed to reproduce the data observed for the alginate beads. Isotherms data were fitted with good correlation using the Langmuir model; alginate and montmorillonite adsorption capacities (q(m)/wet beads) agree with those obtained by various studies.

Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1.

PubMed

Derikvand, Peyman; Etemadifar, Zahra

2014-03-01

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. 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. 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. 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. 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.

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

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

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

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

PubMed

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

2009-01-31

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

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

Facile fabrication of well-defined hydrogel beads with magnetic nanocomposite shells.

PubMed

Liu, Hongxia; Wang, Chaoyang; Gao, Quanxing; Chen, Jianxin; Ren, Biye; Liu, Xinxing; Tong, Zhen

2009-07-06

Well-defined magnetic nanocomposite beads with alginate gel cores and shells of iron oxide (gamma-Fe(2)O(3)) nanoparticles were prepared by self-assembly of colloidal particles at liquid-liquid interfaces and subsequent in situ gelation. Fe(2)O(3) nanoparticles could spontaneously adsorb onto the water droplet surfaces to stabilize water-in-hexane emulsions. Water droplets containing sodium alginate were in situ gelled by calcium cations, which were released from calcium-ethylenediamine tetraacetic acid (Ca-EDTA) chelate by decreasing pH value through slow hydrolysis of d-glucono-delta-lactone (GDL). The resulting hybrid beads with a core-shell structure were easily collected by removing hexane. This facile and high efficient fabrication had a 100% yield and could be carried out at room temperature. Insulin microcrystal was encapsulated into the hybrid beads by dispersing them in the aqueous solution of alginate sodium in the fabrication process. The sustained release could be obtained due to the dual barriers of the hydrogel core and the close-packed inorganic shell. The release curves were nicely fitted by the Weibull equation and the release followed Fickian diffusion. The hybrid beads may find applications as delivery vehicles for biomolecules, drugs, cosmetics, food supplements and living cells.

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

Evaluation of calcium alginate beads for Ce, La and Nd preconcentration from groundwater prior to ICP OES analysis.

PubMed

Arantes de Carvalho, Gabriel G; Kondaveeti, Stalin; Petri, Denise F S; Fioroto, Alexandre M; Albuquerque, Luiza G R; Oliveira, Pedro V

2016-12-01

Analytical methods for the determination of rare earth elements (REE) in natural waters by plasma spectrochemical techniques often require sample preparation procedures for analytes preconcentration as well as for removing matrix constituents, that may interfere on the analytical measurements. In the present work, calcium alginate (CA) beads were used for the first time aiming at Ce, La and Nd preconcentration from groundwater samples for further determination by inductively coupled plasma optical emission spectrometry (ICP OES). Test samples were analyzed in batch mode by transferring a 40mL test portion (pH=5±0.2) into a 50mL polyethylene flask containing 125mg CA beads. After 15min contact, the analytes were quantitatively extracted from the loaded CA beads with 2.0mL of 1.0molL -1 HCl solution for further determination by ICP OES, using Ce (II) 456.236, La (II) 379.478 and Nd (II) 430.358nm emission lines. The proposed approach is a reliable alternative for REE single-stage preconcentration from aqueous samples, as it provided accurate results based on the addition and recovery analysis of groundwater. The results obtained by the proposed method were also compared with those from reference method based on inductively coupled plasma mass spectrometry (ICP-MS) and no significant differences were observed after applying the Student's t-test at 95% confidence level. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Gel bead composition for metal adsorption

DOEpatents

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

1991-01-01

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

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.

Study and Understanding Behavior of Alginate-Inulin Synbiotics Beads for Protection and Delivery of Antimicrobial-Producing Probiotics in Colonic Simulated Conditions.

PubMed

Atia, Abdelbasset; Gomaa, Ahmed; Fernandez, Benoit; Subirade, Muriel; Fliss, Ismail

2018-06-01

According to the World Health Organization (WHO), using antibiotics as growth promoters for livestock-particularly swine-is the principal cause of antibiotic resistance. It is therefore clear that finding an alternative to antibiotics becomes an emergency. Hundreds of recent studies have appointed probiotics as potential candidates to replace or to be used in combination with antibiotics. However, bringing probiotics alive to the colon-their site of action-remains a big challenge because of different physiological barriers encountered in proximal gastrointestinal tract (GIT) such as acidic pH and bile salts that may affect the viability of probiotic cultures. To overcome this problem, in previous studies, we developed and characterize a synbiotic formula consisting of beads of a mixture of alginate and inulin. Three potential probiotics strains namely Pediococcus acidilactici UL5 (UL5), Lactobacillus reuteri (LR), and Lactobacillus salivarius (LS) were encapsulated to study their release and the behavior of this synbiotic formula throughout the GIT using in vitro models. The survival and the release of bacteria from beads were studied by specific PMA-qPCR counting. The microscopic aspects of the beads were studied using scanning electron microscopy (SEM). Moreover, the microbial dynamics inside beads were studied by fluorescence microscopy using the live/dead test. Our results have shown that the beads containing 5% inulin were the most stable in the stomach and throughout the small intestine. However, beads were completely degraded in approximately 3 h of incubation in the fermented medium that mimic the colon. These results were confirmed by SEM and fluorescence microscopy images. Therefore, it can be stated that the AI5 formulation well protected the bacteria in the upper part of the digestive tract and allowed their controlled release in the colon.

Method To immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol

PubMed

Shah; Aebi; Tuor

1998-11-01

Erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. There have been few reported attempts to formulate this natural agent for use in biocontrol. In the current study, factors involved in the immobilization of E. neoaphidis hyphae in an alginate matrix were investigated. Hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. The optimal concentration of low-viscosity sodium alginate for production of conidia from entrapped hyphae was 1.5% (wt/vol), and 0.1 and 0.25 M calcium chloride were equally suitable for use as the gelling solution. Alginate beads were rinsed with 10% sucrose after gelling. However, beads should not be left for longer than 40 min in 0.1 M calcium chloride or 10% sucrose to prevent a 10% loss in conidial production. A 40% (vol/vol) concentration of fungal biomass produced significantly more conidia than either 20% or the standard concentration of 10%. This effect persisted even after beads were dried overnight in a laminar flow hood and stored at 4 degreesC for 4 days. Conidia from freshly produced alginate beads caused 27 to 32% infection in Pea aphids as determined by standardized laboratory bioassays. This finding was not significantly different from infections in aphids inoculated with fresh mycelial mats or plugs from Petri dish cultures. In conclusion, algination appears to be a promising technique for utilizing E. neoaphidis in the biocontrol of aphid pests.

TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

PubMed

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

2014-09-01

The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Fabrication of magnetic alginate beads with uniform dispersion of CoFe2O4 by the polydopamine surface functionalization for organic pollutants removal

NASA Astrophysics Data System (ADS)

Li, Xiaoli; Lu, Haijun; Zhang, Yun; He, Fu; Jing, Lingyun; He, Xinghua

2016-12-01

A simple and efficient method for production of magnetic composites by decorating CoFe2O4 with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe2O4-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe2O4-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe2O4-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe2O4-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0-9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe2O4-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

Alginate as immobilization matrix and stabilizing agent in a two-phase liquid system: application in lipase-catalysed reactions.

PubMed

Hertzberg, S; Kvittingen, L; Anthonsen, T; Skjåk-Braek, G

1992-01-01

Alginate was evaluated as an immobilization matrix for enzyme-catalyzed reactions in organic solvents. In contrast to most hydrogels, calcium alginate was found to be stable in a range of organic solvents and to retain the enzyme inside the gel matrix. In hydrophobic solvents, the alginate gel (greater than 95% water) thus provided a stable, two-phase liquid system. The lipase from Candida cylindracea, after immobilization in alginate beads, catalysed esterification and transesterification in n-hexane under both batch and continuous-flow conditions. The operational stability of the lipase was markedly enhanced by alginate entrapment. In the esterification of butanoic acid with n-butanol, better results were obtained in the typical hydrophilic calcium alginate beads than in less hydrophilic matrices. The effects of substrate concentration, matrix area, and polarity of the substrate alcohols and of the organic solvent on the esterification activity were examined. The transesterification of octyl 2-bromopropanoate with ethanol was less efficient than that of ethyl 2-bromopropanoate with octanol. By using the hydrophilic alginate gel as an immobilization matrix in combination with a mobile hydrophobic phase, a two-phase liquid system was achieved with definite advantages for a continuous, enzyme-catalysed process.

Use of Magnetic Nanoparticles to Monitor Alginate-Encapsulated βTC-tet Cells

PubMed Central

Constantinidis, Ioannis; Grant, Samuel C.; Simpson, Nicholas E.; Oca-Cossio, Jose A.; Sweeney, Carol A.; Mao, Hui; Blackband, Stephen J.; Sambanis, Athanassios

2008-01-01

Non-invasive monitoring of tissue-engineered constructs is an important component in optimizing construct design and assessing therapeutic efficacy. In recent years, cellular and molecular imaging initiatives have spurred the use of iron oxide based contrast agents in the field of NMR imaging. Although their use in medical research has been widespread, their application in tissue engineering has been limited. In this study, the utility of Monocrystalline Iron Oxide Nanoparticles (MION) as an NMR contrast agent was evaluated for βTC-tet cells encapsulated within alginate/poly-L-lysine/alginate (APA) microbeads. The constructs were labeled with MION in two different ways: (a) MION-labeled βTC-tet cells were encapsulated in APA beads (i.e., intracellular compartment); and (b) MION particles were suspended in the alginate solution prior to encapsulation so that the alginate matrix was labeled with MION instead of the cells (i.e., extracellular compartment). The data show that although the location of cells can be identified within APA beads, cell growth or rearrangement within these constructs cannot be effectively monitored, regardless of the location of MION compartmentalization. The advantages and disadvantages of these techniques and their potential use in tissue engineering are discussed. PMID:19165877

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

PubMed

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

2015-01-01

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

Saccharification of citrus wastes by immobilized polygalacturonase in an improved alginate matrix.

PubMed

Ramírez-Tapias, Yuly A; Lapasset Laumann, Aldana S; Britos, Claudia N; Rivero, Cintia W; Trelles, Jorge A

2017-12-01

Enzyme immobilization using hydrogels is a low-cost and effective system for the degradation of bulk pectin derived from orange industry residues. Polygalacturonases obtained from four different bacterial strains of Streptomyces genus were immobilized in alginate gel and assayed for pectin hydrolysis. The enzyme from Streptomyces halstedii ATCC 10897 proved to be superior and more stable within the alginate matrix. Furthermore, a new strategy to improve alginate bead stability using a mixture of calcium and strontium is reported; this technique allowed enhancing the mechanical properties by combining different amounts of these cations for ionotropic gelation. The developed biocatalyst showed maximum hydrolysis at 2 h, generating 1.54 mg/mL of reducing sugars and decreasing the viscosity of polygalacturonic acid by 98.9%. Reusability up to 29 successive reactions (58 h) demonstrated a very stable performance. The heterogeneous biocatalyst was used in the enzymatic saccharification of orange peel albedo (2.23 mg/mL) for adding value to this agro-waste by industrial exploitation.

Hydrogel droplet microarrays with trapped antibody-functionalized beads for multiplexed protein analysis.

PubMed

Li, Huiyan; Leulmi, Rym Feriel; Juncker, David

2011-02-07

Antibody microarrays are a powerful tool for rapid, multiplexed profiling of proteins. 3D microarray substrates have been developed to improve binding capacity, assay sensitivity, and mass transport, however, they often rely on photopolymers which are difficult to manufacture and have a small pore size that limits mass transport and demands long incubation time. Here, we present a novel 3D antibody microarray format based on the entrapment of antibody-coated microbeads within alginate droplets that were spotted onto a glass slide using an inkjet. Owing to the low concentration of alginate used, the gels were highly porous to proteins, and together with the 3D architecture helped enhance mass transport during the assays. The spotting parameters were optimized for the attachment of the alginate to the substrate. Beads with 0.2 µm, 0.5 µm and 1 µm diameter were tested and 1 µm beads were selected based on their superior retention within the hydrogel. The beads were found to be distributed within the entire volume of the gel droplet using confocal microscopy. The assay time and the concentration of beads in the gels were investigated for maximal binding signal using one-step immunoassays. As a proof of concept, six proteins including cytokines (TNFα, IL-8 and MIP/CCL4), breast cancer biomarkers (CEA and HER2) and one cancer-related protein (ENG) were profiled in multiplex using sandwich assays down to pg mL(-1) concentrations with 1 h incubation without agitation in both buffer solutions and 10% serum. These results illustrate the potential of beads-in-gel microarrays for highly sensitive and multiplexed protein analysis.

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

PubMed

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

2015-05-21

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

Preparation, characterization and catalytic behavior of pectinase covalently immobilized onto sodium alginate/graphene oxide composite beads.

PubMed

Dai, Xiao-Yan; Kong, Li-Min; Wang, Xiao-Ling; Zhu, Qing; Chen, Kai; Zhou, Tao

2018-07-01

Pectinase was immobilized onto sodium alginate/graphene oxide beads via amide bonds by using N,N'-dicyclohexylcarbodiimide/N-hydroxysuccinimide as the activating agent. The immobilized pectinase was characterized by Fourier transform infrared spectra and scanning electron microscopy analyses. Immobilization conditions were optimized by Box-Behnken design and the response surface method. The activity of the immobilized pectinase prepared under optimal conditions reached 1236.86 ± 40.21 U/g, with an enzyme activity recovery of 83.5%. The optimal pH of free pectinase was 4.5, while that of immobilized pectinase was shifted to 4.0. The optimal temperature of immobilized pectinase was increased to 60 °C, which was 10 °C higher than that of free form. Furthermore, the immobilized pectinase possessed a superior thermal stability and storage stability to those of free pectinase. Reusability studies indicated that the immobilized pectinase retained 73% of initial activity after six times cycles. Due to these good properties, such immobilized pectinase may find application in food industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Magneto-responsive alginate capsules.

PubMed

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

2015-05-20

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.

Enhanced removal of bisphenol-AF by activated carbon-alginate beads with cetyltrimethyl ammonium bromide.

PubMed

Tang, Zheng; Peng, Sha; Hu, Shuya; Hong, Song

2017-06-01

Adsorption removal of bisphenol-AF (BPAF) from aqueous solutions by synthesized activated carbon-alginate beads (AC-AB) with cetyltrimethyl ammonium bromide (CTAB) has been studied using two ways. The traditional method (two-step) first synthesized CTAB-modified AC-AB (AC-AB-CTAB), then used it to remove BPAF by adsorption. And one-step method dispersed AC-AB and CTAB in wastewater, followed by the removal of BPAF accompanied with the synthesis of AC-AB-CTAB. The one-step method showed a better performance than the two-step method, achieving a maximum removal of BPAF with 284.6mg/g. Kinetic studies and adsorption isotherms indicated that adsorption process of BPAF on AC-AB by the one-step method could be expressed by a pseudo-second-order model and a Dubinin-Ashtakhov (D-A) isotherm, respectively. The effects of pH, ionic strength, and inorganic ions on BPAF adsorption were also investigated. Furthermore, hydrophobic interactions, hydrogen bonds, and π-π electron donor-acceptor (EDA) interactions were discussed to explain the enhanced adsorption behavior of BPAF on AC-AB with CTAB. The findings verified the effectiveness of AC-AB for the removal of BPAF from wastewater and its high stability within five regeneration cycles. Copyright © 2017 Elsevier Inc. All rights reserved.

Controlled Electrospray Generation of Nonspherical Alginate Microparticles.

PubMed

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

2017-12-11

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

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

PubMed

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

2010-12-01

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

A BOD monitoring disposable reactor with alginate-entrapped bacteria.

PubMed

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

2010-10-01

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

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.

A new efficient method of generating photoaffinity beads for drug target identification.

PubMed

Nishiya, Yoichi; Hamada, Tomoko; Abe, Masayuki; Takashima, Michio; Tsutsumi, Kyoko; Okawa, Katsuya

2017-02-15

Affinity purification is one of the most prevalent methods for the target identification of small molecules. Preparation of an appropriate chemical for immobilization, however, is a tedious and time-consuming process. A decade ago, a photoreaction method for generating affinity beads was reported, where compounds are mixed with agarose beads carrying a photoreactive group (aryldiazirine) and then irradiated with ultraviolet light under dry conditions to form covalent attachment. Although the method has proven useful for identifying drug targets, the beads suffer from inefficient ligand incorporation and tend to shrink and aggregate, which can cause nonspecific binding and low reproducibility. We therefore decided to craft affinity beads free from these shortcomings without compromising the ease of preparation. We herein report a modified method; first, a compound of interest is mixed with a crosslinker having an activated ester and a photoreactive moiety on each end. This mixture is then dried in a glass tube and irradiated with ultraviolet light. Finally, the conjugates are dissolved and reacted with agarose beads with a primary amine. This protocol enabled us to immobilize compounds more efficiently (approximately 500-fold per bead compared to the original method) and generated beads without physical deterioration. We herein demonstrated that the new FK506-immobilized beads specifically isolated more FKBP12 than the original beads, thereby proving our method to be applicable to target identification experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzyme-entrapping behaviors in alginate fibers and their papers

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 moleculesmore » 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).« less

Oral immunization of Carassius auratus with modified recombinant A-layer proteins entrapped in alginate beads.

PubMed

Maurice, Sarah; Nussinovitch, Amos; Jaffe, Nicole; Shoseyov, Oded; Gertler, Arieh

2004-12-09

This study was focused on the utilization of a recombinant expression system to produce a unique modified subunit vaccine possessing a self-contained delivery system which could potentially improve the uptake and delivery of vaccine products as well their immunogenic potential. For this purpose the A-layer protein (At-R) associated with the fish pathogen atypical Aeromonas salmonicida was cloned and modified by the genetic fusion of the protein transduction domain (MTS) derived from Kaposi fibroblast growth factor (At-MTS). The potential for these proteins to be employed as antigens for oral immunization of goldfish was examined by encapsulation of At-R, At-MTS and the control, BSA, into biodegradable alginate gel macrospheres which were fed to goldfish in place of standard pellet fish feed. The bead physical properties were modified only in the presence of At-R and the temporal release of proteins was significantly less when At-MTS was employed. Western blot analysis of serum samples collected from fish following intubation with the recombinant proteins determined that the rate of protein uptake from the digestive tract into the blood system improved considerably when MTS was fused to At-R. Experimental fish were fed one of three protein-alginate formulae on a schedule of 3 days/week or 5 days/month for a period of 2 months. After 1 month, animals fed on the 5-day protocol demonstrated increased serum antibody titers while following an additional month of feeding this level decreased and titers were found to be higher in fish maintained on the 3-day regime. Fish fed At-MTS maintained the highest titer at the end of 2-month period. To determine whether the diminished antibody titers were a result of oral tolerance fish were injected intraperitoneally with the At-R antigen. Only experimental groups which had been fed At-R or At-MTS demonstrated increased antibody titers which paralleled a typical secondary humoral response. In spite of the presence of an increased

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Generation of Stable Co-Cultures of Vascular Cells in a Honeycomb Alginate Scaffold

PubMed Central

Yamamoto, Masaya; James, Daylon; Li, Hui; Butler, Jason; Rafii, Shahin

2010-01-01

Scaffold-guided vascular tissue engineering has been investigated as a means to generate functional and transplantable vascular tissue grafts that increase the efficacy of cell-based therapeutic strategies in regenerative medicine. In this study, we employed confocal microscopy and three-dimensional reconstruction to assess the engraftment and growth potential of vascular cells within an alginate scaffold with aligned pores. We fabricated honeycomb alginate scaffolds with aligned pores, whose surface was immobilized with fibronectin and subsequently coated with matrigel. Endothelial cells were seeded into aligned pore scaffolds in the presence and absence of human smooth muscle cells. We showed that endothelial cells seeded into alginate scaffolds attach on the surface of aligned pores in vitro, giving rise to stable co-cultures of vascular cells. Moreover, the three-dimensional alginate depots containing the cells were exposed to laminar flow in order to recapitulate physiological shear stress found in the vasculature in vivo. After the flow exposure, the scaffold remained intact and some cells remained adherent to the scaffold and aligned in the flow direction. These studies demonstrate that alginate scaffolds provide a suitable matrix for establishing durable angiogenic modules that may ultimately enhance organ revascularization. PMID:19705957

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

Calcium alginate gel as encapsulation matrix for coimmobilized enzyme systems.

PubMed

Blandino, A; Macías, M; Cantero, D

2003-07-01

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

Formulation and statistical optimization of gastric floating alginate/oil/chitosan capsules loading procyanidins: in vitro and in vivo evaluations.

PubMed

Chen, Rencai; Guo, Xiaomin; Liu, Xuecong; Cui, Haiming; Wang, Rui; Han, Jing

2018-03-01

The aim of the present work was to develop gastric floating capsules containing oil-entrapped beads loading procyanidins. The floating beads were prepared by ionotropic gelation method using sodium alginate, CaCl 2 and chitosan. The effect of three independent parameters (concentration of sodium alginate, CaCl 2 and chitosan) on entrapment efficiency were analyzed by Box-Behnken design. The floating beads were evaluated for surface morphology, particle size, density, entrapment efficiency, buoyancy, release behavior in vitro and floating ability in vivo. The prepared beads were grossly spherical in shape and the mean size was approximately 1.54±0.17mm. The density was 0.97g/cm 3 . And the optimal conditions were as follows: concentration of sodium alginate, CaCl 2 and chitosan were 33.75mg/mL, 9.84mg/mL and 9.05mg/mL, respectively. The optimized formulation showed entrapment efficiency of 88.84±1.04% within small error-value (0.65). The release mechanism of floating capsules followed Korsmeyer-Peppas model (r 2 =0.9902) with non-Fickian release. The gastric floating capsules exhibited 100% floating percentage in vitro and they could float on the top of gastric juice for 5h in vivo. Therefore, the floating capsules are able to prolong the gastroretentive delivery of procyanidins. Copyright © 2017 Elsevier B.V. All rights reserved.

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

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. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

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.

Alginate based nanocomposite for microencapsulation of probiotic: Effect of cellulose nanocrystal (CNC) and lecithin.

PubMed

Huq, Tanzina; Fraschini, Carole; Khan, Avik; Riedl, Bernard; Bouchard, Jean; Lacroix, Monique

2017-07-15

Probiotic (Lactobacillus rhamnosus ATCC 9595) was encapsulated in alginate-CNC-lecithin microbeads to produce nutraceutical microcapsules. Addition of CNC and lecithin in alginate microbeads (ACL-1) improved the viability of L. rhamnosus during gastric passage and storage. The compression strength of the freeze-dried ACL-1 microbeads improved 40% compared to alginate microbeads alone. Swelling studies revealed that addition of CNC and lecithin in alginate microbeads decreased (around 47%) the gastric fluid absorption but increased the dissolution time by 20min compared to alginate microbeads (A-0). During transition through the gastric passage, the viability of L. rhamnosus in dried ACL-1 microbeads was increased 37% as compared to A-0 based beads. At 25 and 4°C storage conditions, the viability of L. rhamnosus encapsulated in ACL-1 microbeads decreased by 1.23 and 1.08 log respectively, whereas the encapsulation with A-0 microbeads exhibited a 3.17 and 1.93 log reduction respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

First transplantation of isolated murine follicles in alginate.

PubMed

Vanacker, Julie; Dolmans, Marie-Madeleine; Luyckx, Valérie; Donnez, Jacques; Amorim, Christiani A

2014-01-01

Our aim is to develop an artificial ovary allowing survival and growth of isolated follicles and ovarian cells, to restore fertility in women diagnosed with pathologies at high risk of ovarian involvement. For this, alginate beads containing isolated preantral follicles and ovarian cells were autografted to immunocompetent mice. One week after grafting, the beads were invaded by proliferating murine cells (12.1%) and capillaries. The recovery rate of follicles per graft ranged from 0% to 35.5%. Of the analyzed follicles, 77% were Ki67-positive and 81%, TUNEL-negative. Three antral follicles were also identified, evidencing their ability to grow in the matrix. Our results suggest that an artificial ovary is now conceivable, opening new perspectives to restore fertility in women.

Synthesis and characterization of alginate beads encapsulated zinc oxide nanoparticles for bacteria disinfection in water.

PubMed

Motshekga, Sarah Constance; Sinha Ray, Suprakas; Maity, Arjun

2018-02-15

The use of polymer nanocomposites as novel materials for water remediation has emerged as a promising alternative for disinfection of bacteria contaminated water. Sodium alginate, a natural biopolymer has been investigated in this study by encapsulating antimicrobial zinc oxide nanoparticles supported bentonite. The confirmation of the alginate nanocomposites was done by use of TEM, SEM-EDS and XRD. The antimicrobial activity of the alginate nanocomposites was investigated by batch studies using surface water and synthetic bacteria contaminated water containing Staphylococcus aureus. The effect of nanocomposite amount and initial bacteria concentration has been studied. The inactivation results indicated that the nanocomposite effectively inactivated bacteria in both the synthetic and surface water. With an amount of 0.5 g of the nanocomposites, no bacteria was observed in the water after 70 min of contact time with initial bacteria concentration of 200 cfu/ml for synthetic water and within a min, no bacteria was observed in the water for surface water. It is worth noting that 200 cfu/ml is the bacteria concentration range in which environmental water is likely to contain. Therefore, the results of this study have indicated that the alginate nanocomposites can be deemed as a potential antimicrobial agent for water disinfection. Copyright © 2017 Elsevier Inc. All rights reserved.

Gums induced microstructure stability in Ca(II)-alginate beads containing lactase analyzed by SAXS.

PubMed

Traffano-Schiffo, Maria Victoria; Castro-Giraldez, Marta; Fito, Pedro J; Perullini, Mercedes; Santagapita, Patricio R

2018-01-01

Previous works show that the addition of trehalose and gums in β-galactosidase (lactase) Ca(II)-alginate encapsulation systems improved its intrinsic stability against freezing and dehydration processes in the pristine state. However, there is no available information on the evolution in microstructure due to the constraints imposed by the operational conditions. The aim of this research is to study the time course of microstructural changes of Ca(II)-alginate matrices driven by the presence of trehalose, arabic and guar gums as excipients and to discuss how these changes influence the diffusional transport (assessed by LF-NMR) and the enzymatic activity of the encapsulated lactase. The structural modifications at different scales were assessed by SAXS. The incorporation of gums as second excipients induces a significant stabilization in the microstructure not only at the rod scale, but also in the characteristic size and density of alginate dimers (basic units of construction of rods) and the degree of interconnection of rods at a larger scale, improving the performance in terms of lactase activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Degradation of complex carbohydrate: immobilization of pectinase from Bacillus licheniformis KIBGE-IB21 using calcium alginate as a support.

PubMed

Rehman, Haneef Ur; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio; Ansari, Asma

2013-08-15

Pectinases are heterogeneous group of enzymes that catalyse the hydrolysis of pectin substances which is responsible for the turbidity and undesirable cloudiness in fruits juices. In current study, partially purified pectinase from Bacillus licheniformis KIBGE-IB21 was immobilized in calcium alginate beads. The effect of sodium alginate and calcium chloride concentration on immobilization was studied and it was found that the optimal sodium alginate and calcium chloride concentration was 3.0% and 0.2 M, respectively. It was found that immobilization increases the optimal reaction time for pectin degradation from 5 to 10 min and temperature from 45 to 55°C, whereas, the optimal pH remained same with reference to free enzyme. Thermal stability of enzyme increased after immobilization and immobilized pectinase retained more than 80% of its initial activity after 5 days at 30°C as compared with free enzyme which showed only 30% of residual activity. The immobilized enzyme also exhibited good operational stability and 65% of its initial activity was observed during third cycle. In term of pectinase immobilization efficiency and stability, this calcium alginate beads approach seemed to permit good results and can be used to make a bioreactor for various applications in food industries. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-08-01

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

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.

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.

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.

In vitro chlorhexidine release from alginate based microbeads for periodontal therapy

PubMed Central

Reske, Thomas; Böhmer, Femke; Hornung, Anne; Grabow, Niels; Lang, Hermann

2017-01-01

Periodontitis is one of the most common infectious diseases globally that, if untreated, leads to destruction of the tooth supporting tissues and finally results in tooth loss. Evidence shows that standard procedures as mechanical root cleaning could be supported by further treatment options such as locally applied substances. Due to gingival crevicular fluid flow, substances are commonly washed out off the periodontal pockets. The evaluation of administration techniques and the development of local drug releasing devices is thus an important aspect in periodontal research. This study describes the development and examination of a new alginate based, biodegradable and easily applicable drug delivery system for chlorhexidine (CHX). Different micro beads were produced and loaded with CHX and the release profiles were investigated by high performance liquid chromatography (HPLC). The in vitro-demonstrated release of CHX from alginate based beads shows comparable releasing characteristics as clinically approved systems. Yet many characteristics of this new delivery system show to be favourable for periodontal therapy. Easy application by injection, low production costs and multifunctional adaptions to patient related specifics may improve the usage in routine care. PMID:28973028

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

PubMed

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

2014-01-01

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

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

PubMed Central

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

2017-01-01

Sodium alginate is an effective biomaterial for tissue engineering applications. Non-purified alginate is contaminated with protein, lipopolysaccharide, DNA, and RNA, which could elicit adverse immunological reactions. We developed a purification protocol to generate biocompatible alginate based on (a) activated charcoal treatment, (b) use of hydrophobic membrane filtration (we used hydrophobic polyvinylidene difluoride membranes to remove organic contaminants), (c) dialysis, and finally (d) ethanol precipitation. Using this approach, we could omit pre-treatment with chloroform and significantly reduce the quantities of reagents used. Purification resulted in reduction of residual protein by 70% down to 0.315 mg/g, DNA by 62% down to 1.28 μg/g, and RNA by 61% down to less than 10 μg/g, respectively. Lipopolysaccharide levels were reduced by >90% to less than 125 EU/g. Purified alginate did not induce splenocyte proliferation in vitro. Three-dimensional scaffolds generated from purified alginate did not elicit a significant foreign body reaction, fibrotic overgrowth, or macrophage infiltration 4 weeks after implantation. This study describes a simplified and economical alginate purification method that results in alginate purity, which meets clinically useful criteria. PMID:27114440

Encapsulation of probiotic bacteria with alginate-starch and evaluation of survival in simulated gastrointestinal conditions and in yoghurt.

PubMed

Sultana, K; Godward, G; Reynolds, N; Arumugaswamy, R; Peiris, P; Kailasapathy, K

2000-12-05

A modified method using calcium alginate for the microencapsulation of probiotic bacteria is reported in this study. Incorporation of Hi-Maize starch (a prebiotic) improved encapsulation of viable bacteria as compared to when the bacteria were encapsulated without the starch. Inclusion of glycerol (a cryo-protectant) with alginate mix increased the survival of bacteria when frozen at -20 degrees C. The acidification kinetics of encapsulated bacteria showed that the rate of acid produced was lower than that of free cultures. The encapsulated bacteria, however, did not demonstrate a significant increase in survival when subjected to in vitro high acid and bile salt conditions. A preliminary study was carried out in order to monitor the effects of encapsulation on the survival of Lactobacillus acidophilus and Bifidobacterium spp. in yoghurt over a period of 8 weeks. This study showed that the survival of encapsulated cultures of L. acidophilus and Bifidobacterium spp. showed a decline in viable count of about 0.5 log over a period of 8 weeks while there was a decline of about 1 log in cultures which were incorporated as free cells in yoghurt. The encapsulation method used in this study did not result in uniform bead size, and hence additional experiments need to be designed using uniform bead size in order to assess the role of different encapsulation parameters, such as bead size and alginate concentration, in providing protection to the bacteria.

Binding and Leakage of Barium in Alginate Microbeads

PubMed Central

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

2013-01-01

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

Binding and leakage of barium in alginate microbeads.

PubMed

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

2012-11-01

Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. Copyright © 2012 Wiley Periodicals, Inc.

Alginate Bead-Encapsulated PEDF Induces Ectopic Bone Formation In Vivo in the Absence of Co-Administered Mesenchymal Stem Cells.

PubMed

Elahy, Mina; Doschak, Michael R; Hughes, Jeffery D; Baindur-Hudson, Swati; Dass, Crispin R

2018-01-01

Bone defects can be severely debilitating and reduce quality of life. Osteoregeneration can alleviate some of the complications in bony defects. For therapeutic use in future, a single factor that can cause potent bone regeneration is highly preferred as it will be more costeffective, any off-target effects will be more easily monitored and potentially managed, and for ease of administration which would lead to better patient compliance and satisfaction. We demonstrate that pigment epithelium-derived factor (PEDF), one such factor that is known to be potent against angiogenesis, promotes osteoblastogenesis in mesenchymal stem cells in vitro, but does not need co-encapsulation of cells in alginate bead scaffolds for osteogeneration in vivo. Osteogenic differentiation by PEDF in vitro was confirmed with immunoblotting and immunocytochemical staining for bone markers (alkaline phosphatase, osteocalcin, osteopontin, collagen I), calcified mineral deposition, and assay for alkaline phosphatase activity. PEDF-mediated bone formation in a muscle pocket in vivo model was confirmed by microcomputed tomography (microCT), histology (haematoxylin and eosin, Alcian blue staining), immunostaining for bone markers and for collagen I-processing proteins (heat shock protein 47 and membrane type I matrix metalloproteinase). PEDF therefore presents itself as a promising biological for osteogeneration. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

Towards a fully synthetic substitute of alginate: optimization of a thermal gelation/chemical cross-linking scheme ("tandem" gelation) for the production of beads and liquid-core capsules.

PubMed

Cellesi, F; Weber, W; Fussenegger, M; Hubbell, J A; Tirelli, N

2004-12-20

Fully synthetic polymers were used for the preparation of hydrogel beads and capsules, in a processing scheme that, originally designed for calcium alginate, was adapted to a "tandem" process, that is the combination a physical gelation with a chemical cross-linking. The polymers feature a Tetronic backbone (tetra armed Pluronics), which exhibits a reverse thermal gelation in water solutions within a physiological range of temperatures and pHs. The polymers bear terminal reactive groups that allow for a mild, but effective chemical cross-linking. Given an appropriate temperature jump, the thermal gelation provides a hardening kinetics similar to that of alginate. With slower kinetics, the chemical cross-linking then develops an irreversible and elastic gel structure, and determines its transport properties. In the present article this process has been optimized for the production of monodisperse, high elastic, hydrogel microbeads, and liquid-core microcapsules. We also show the feasibility of the use of liquid-core microcapsules in cell encapsulation. In preliminary experiments, CHO cells have been successfully encapsulated preserving their viability during the process and after incubation. The advantages of this process are mainly in the use of synthetic polymers, which provide great flexibility in the molecular design. This, in principle, allows for a precise tailoring of mechanical and transport properties and of bioactivity of the hydrogels, and also for a precise control in material purification.

Microfluidic Bead Suspension Hopper

PubMed Central

2014-01-01

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

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

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.

Alginate beads as a tool to handle, cryopreserve and culture isolated human primordial/primary follicles.

PubMed

Camboni, A; Van Langendonckt, A; Donnez, J; Vanacker, J; Dolmans, M M; Amorim, C A

2013-08-01

One major concern of grafting cryopreserved ovarian tissue to restore fertility in cancer patients is the possibility of reintroducing tumor cells. Cryopreservation of isolated primordial/primary follicles (PFs) may circumvent this problem. The aim of our work was to compare dimethyl sulfoxide (ME2SO) and ethylene glycol (EG) as cryoprotectants (CPAs) for slow-freezing of isolated human PFs in alginate. Ovarian biopsies from four women were processed for follicle isolation. PFs were embedded in alginate (5-15 per group). Follicles were frozen-thawed using 1.4M ME2SO or 1.5M EG as CPAs. Fresh and cryopreserved isolated follicles were in vitro cultured (IVC) for 7 days. At different time periods (after isolation, cryopreservation and IVC), follicles were evaluated with live/dead assay (using fluorescent probes) and diameter measurement. Follicle viability was calculated according to the percentage of dead follicular cells and the presence of a live/dead oocyte. A total of 841 PFs were isolated, embedded in alginate and cryopreserved with ME2SO (n=424) or EG (n=259), or used as controls (n=158). After 7 days of IVC, a significant increase in follicle size was observed in the fresh and ME2SO groups, but not in the EG group. The percentage of totally viable PFs was not significantly different before or after seven days of culture in fresh (100% and 82%) or ME2SO (93.2% and 85.1%) tissue. The EG group showed significantly lower viability before (63.9%) and after IVC (66.2%) than the fresh and ME2SO groups. Our results show that 1.4M ME2SO yields better preservation of isolated PF viability after thawing and 7 days of IVC than 1.5M EG. Alginate constitutes an easy, safe hydrogel matrix to handle and cryopreserve isolated human follicles using ME2SO as a CPA. Copyright © 2013 Elsevier Inc. All rights reserved.

Equilibrium isotherms, kinetics, and thermodynamics studies for congo red adsorption using calcium alginate beads impregnated with nano-goethite.

PubMed

Munagapati, Venkata Subbaiah; Kim, Dong-Su

2017-07-01

The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature. Copyright © 2017 Elsevier Inc. All rights reserved.

Chondrocyte response to cyclic hydrostatic pressure in alginate versus pellet culture.

PubMed

Elder, Steven H; Sanders, Shawn W; McCulley, William R; Marr, Misti L; Shim, Joon W; Hasty, Karen A

2006-04-01

Cells are often cultured at high density (e.g., confluent monolayer and as pellets) to promote chondrogenic differentiation and to maintain the chondrocyte phenotype. They are also frequently suspended in hydrogels such as agarose or alginate for the same purposes. These culture techniques differ markedly with respect to frequency of direct contact between cells and overall intercellular spacing. Because these factors may significantly affect mechanotransduction, the purpose of this study was to determine if the response of articular chondrocytes to cyclic hydrostatic pressure would depend on the culture condition. Primary articular chondrocytes from young and mature pigs were cultured either as pellets or suspended in alginate beads. Both groups were exposed to dynamic hydrostatic pressure (4 MPa, 1 Hz, 5400 cycles per day) for 7 days. Cell proliferation was unaffected by pressure, but pressurized chondrocytes in pellet culture had significantly greater sGAG content and incorporated [3H]proline at a higher rate than nonpressurized controls. Electron microscopy revealed a fibrous extracellular matrix (ECM) surrounding pellets, but not cells in alginate. In addition, expression of Connexin 43 (Cx43) mRNA was slightly lower in alginate than in pellet cultures and was not significantly altered by loading. Thus, metabolic response of chondrocytes to dynamic hydrostatic pressure was affected by culture technique; chondrocytes cultured as pellets exhibited the classical anabolic response to dynamic hydrostatic pressure, but those in alginate did not. Although cell-ECM interaction could be important, the differential response is not likely attributable to differential expression of Cx43 mRNA. Copyright 2006 Orthopaedic Research Society

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

Optimization of pectinase immobilization on grafted alginate-agar gel beads by 24 full factorial CCD and thermodynamic profiling for evaluating of operational covalent immobilization.

PubMed

Abdel Wahab, Walaa A; Karam, Eman A; Hassan, Mohamed E; Kansoh, Amany L; Esawy, Mona A; Awad, Ghada E A

2018-07-01

Pectinase produced by a honey derived from the fungus Aspergillus awamori KX943614 was covalently immobilized onto gel beads made of alginate and agar. Polyethyleneimine, glutaraldehyde, loading time and enzyme's units were optimized by 2 4 full factorial central composite design (CCD). The immobilization process increased the optimal working pH for the free pectinase from 5 to a broader range of pH4.5-5.5 and the optimum operational temperature from 55°C to a higher temperature, of 60°C, which is favored to reduce the enzyme's microbial contamination. The thermodynamics studies showed a thermal stability enhancement against high temperature for the immobilized formula. Moreover, an increase in half-lives and D-values was achieved. The thermodynamic studies proved that immobilization of pectinase made a remarkable increase in enthalpy and free energy because of enzyme stability enhancement. The reusability test revealed that 60% of pectinase's original activity was retained after 8 successive cycles. This gel formula may be convenient for immobilization of other industrial enzymes. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PVA-chitosan composite hydrogel versus alginate beads as a potential mesenchymal stem cell carrier for the treatment of focal cartilage defects.

PubMed

Dashtdar, Havva; Murali, Malliga Raman; Abbas, Azlina Amir; Suhaeb, Abdulrazzaq Mahmod; Selvaratnam, Lakshmi; Tay, Liang Xin; Kamarul, Tunku

2015-05-01

To investigate whether mesenchymal stem cells (MSCs) seeded in novel polyvinyl alcohol (PVA)-chitosan composite hydrogel can provide comparable or even further improve cartilage repair outcomes as compared to previously established alginate-transplanted models. Medial femoral condyle defect was created in both knees of twenty-four mature New Zealand white rabbits, and the animals were divided into four groups containing six animals each. After 3 weeks, the right knees were transplanted with PVA-chitosan-MSC, PVA-chitosan scaffold alone, alginate-MSC construct or alginate alone. The left knee was kept as untreated control. Animals were killed at the end of 6 months after transplantation, and the cartilage repair was assessed through Brittberg morphological score, histological grading by O'Driscoll score and quantitative glycosaminoglycan analysis. Morphological and histological analyses showed significant (p < 0.05) tissue repair when treated with PVA-chitosan-MSC or alginate MSC as compared to the scaffold only and untreated control. In addition, safranin O staining and the glycosaminoglycan (GAG) content were significantly higher (p < 0.05) in MSC treatment groups than in scaffold-only or untreated control group. No significant difference was observed between the PVA-chitosan-MSC- and alginate-MSC-treated groups. PVA-chitosan hydrogel seeded with mesenchymal stem cells provides comparable treatment outcomes to that of previously established alginate-MSC construct implantation. This study supports the potential use of PVA-chitosan hydrogel seeded with MSCs for clinical use in cartilage repair such as traumatic injuries.

Effect of Eudragit S100 nanoparticles and alginate chitosan encapsulation on the viability of Lactobacillus acidophilus and Lactobacillus rhamnosus.

PubMed

Ansari, Fereshteh; Pourjafar, Hadi; Jodat, Vahid; Sahebi, Javad; Ataei, Amir

2017-12-01

In this study, we examined a novel method of microencapsulation with calcium alginate-chitosan and Eudragit S100 nanoparticles for the improving viability of probiotic bacteria, Lactobacillus acidophilus and Lactobacillus rhamnosus. Extrusion technique was carried out in microencapsulation process. The viability of two probiotics in single coated beads (with only chitosan), double coated beads (with chitosan and Eudragit nanoparticles), and as free cells (unencapsulated) were conducted in simulated gastric juice (pH 1.55, without pepsin) followed by incubation in simulated intestinal juice (pH 7.5, with 1% bile salt). In case of single coated beads, presumably, lack of sufficient strength of chitosan under simulated gastric condition was the main reason of 4-log and 5-log reduction of the counts of the L. acidophilus and L. rhamnosus respectively. The results showed that with the second coat forming (Eudragit nanoparticles) over the first coat (chitosan), the strength of the beads and then viability rate of the bacteria were increased in comparison with the single coated beads.

Sodium alginate/graphene oxide hydrogel beads as permeable reactive barrier material for the remediation of ciprofloxacin-contaminated groundwater.

PubMed

Zhao, Pingping; Yu, Fei; Wang, Ruoyu; Ma, Yao; Wu, Yanqing

2018-06-01

The wide occurrence of antibiotics in groundwater has raised serious concerns due to their impacts on humans and the ecosystem. Most of the research in groundwater remediation focuses on the exploitation of nano-materials. However, nano-materials have several disadvantages such as high production cost, rapid reduction in permeability, disposal problems, and high sensitivity to environmental conditions. To solve these issues, novel sodium alginate/graphene oxide hydrogel beads (GSA) were synthesised and their effectiveness as permeable reactive barrier (PRB) backfill material in the remediation of ciprofloxacin (CPX)-contaminated groundwater was tested. The adsorption of CPX onto GSA followed the pseudo-second-order kinetic model. The isotherm data followed the Freundlich model. The maximum adsorption capacity was 100 mg g -1 at pH 7.0. The adsorption process was sensitive to contact time, initial CPX concentration and ionic strength. However, it was not pH sensitive. Hydrophobic interaction, electrostatic interaction, ion exchange, H-bonding, and pore filling were proposed to be the main adsorption mechanisms. The effects of flow rate, influent CPX concentration, and ionic strength on the performance of PRB were confirmed through flow-through column experiments and by using a chemical non-equilibrium two-site model. Accordingly, a proper PRB was designed based on hydrogeological conditions. Finally, the lifetime and cost of the PRBs were calculated. The results obtained provided concrete evidence that GSA is a promising adsorbent material for PRBs applications in the remediation of CPX-contaminated groundwater. Copyright © 2018 Elsevier Ltd. All rights reserved.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Fabrication of a microfluidic device for studying the in situ drug-loading/release behavior of graphene oxide-encapsulated hydrogel beads.

PubMed

Veerla, Sarath Chandra; Kim, Da Reum; Yang, Sung Yun

2018-01-01

Controlled drug delivery system is highly important for not only prolonged the efficacy of drug but also cellular development for tissue engineering. A number of biopolymer composites and nanostructured carriers behave been used for the controlled drug delivery of therapeutics. Recently, in vitro microfluidic devices that mimic the human body have been developed for drug-delivery applications. A microfluidic channel was fabricated via a two-step process: (i) polydimethyl siloxane (PDMS) and curing agent were poured with a 10:2 mass ratio onto an acrylic mold with two steel pipes, and (ii) calcium alginate beads were synthesized using sodium alginate and calcium chloride solutions. Different amounts (10, 25, 50 μg) of graphene oxide (GO) were then added by Hummers method, and studies on the encapsulation and release of the model drug, risedronate (Ris), were performed using control hydrogel beads (pH 6.3), GO-containing beads (10GO, 25GO and 50GO), and different pH conditions. MC3T3 osteoblastic cells were cultured in a microchannel with Ris-loaded GO-hydrogel beads, and their proliferation, viability, attachment and spreading were assessed for a week. The spongy and textured morphology of pristine hydrogel beads was converted to flowery and rod-shaped structures in drug-loaded hydrogel beads at reduced pH (6.3) and at a lower concentration (10 μg) of GO. These latter 10GO drug-loaded beads rapidly released their cargo owing to the calcium phosphate deposited on the surface. Notably, beads containing a higher amount of GO (50GO) exhibited an extended drug-release profile. We further found that MC3T3 cells proliferated continuously in vitro in the microfluidic channel containing the GO-hydrogel system. MTT and live/dead assays showed similar proliferative potential of MC3T3 cells. Therefore, a microfluidic device with microchannels containing hydrogel beads formulated with different amounts of GO and tested under various pH conditions could be a promising system

Praseodymium sorption on Laminaria digitata algal beads and foams.

PubMed

Wang, Shengye; Hamza, Mohammed F; Vincent, Thierry; Faur, Catherine; Guibal, Eric

2017-10-15

Algal (Laminaria digitata) beads and algal foams have been prepared by a new synthesis mode and the sorbents were tested for praseodymium sorption in batch and fixed-bed like systems (recirculation or one-pass modes), respectively. Metal binding occurs through ion-exchange with Ca(II) ions used for ionotropic gelation of alginate contained in the algal biomass and eventually with protons. Sorption isotherms at pH 4 are described by the Langmuir and the Sips equations with maximum sorption capacities close to 110-120mgPrg -1 . Uptake kinetics are fitted by the pseudo-second order reaction rate equation for both beads and foams; in the case of beads the Crank equation also gives good fit of experimental data. Metal is successfully desorbed using 2M HCl/0.05M CaCl 2 solutions and the sorbent can be efficiently re-used for a minimum of 5 cycles with negligible decrease in sorption/desorption properties and appreciable concentrating effect (around 8-10 times the initial metal concentration). Tested in continuous mode, the algal foam shows typical breakthrough curves that are fitted by the Yan method; desorption is also efficient and allows under the best conditions to achieve a concentration factor close to 8. Copyright © 2017 Elsevier Inc. All rights reserved.

Formulation of an alginate-vineyard pruning waste composite as a new eco-friendly adsorbent to remove micronutrients from agroindustrial effluents.

PubMed

Vecino, X; Devesa-Rey, R; Moldes, A B; Cruz, J M

2014-09-01

The cellulosic fraction of vineyard pruning waste (free of hemicellulosic sugars) was entrapped in calcium alginate beads and evaluated as an eco-friendly adsorbent for the removal of different nutrients and micronutrients (Mg, P, Zn, K, N-NH4, SO4, TN, TC and PO4) from an agroindustrial effluent (winery wastewater). Batch adsorption studies were performed by varying the amounts of cellulosic adsorbent (0.5-2%), sodium alginate (1-5%) and calcium chloride (0.05-0.9M) included in the biocomposite. The optimal formulation of the adsorbent composite varied depending on the target contaminant. Thus, for the adsorption of cationic contaminants (Mg, Zn, K, N-NH4 and TN), the best mixture comprised 5% sodium alginate, 0.05M calcium chloride and 0.5% cellulosic vineyard pruning waste, whereas for removal of anionic compounds (P, SO4 and PO4), the optimal mixture comprised 1% sodium alginate, 0.9M calcium chloride and 0.5% cellulosic vineyard pruning waste. To remove TC from the winery wastewater, the optimal mixture comprised 3% of sodium alginate, 0.475M calcium chloride and 0.5% cellulosic vineyard pruning waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

The biofilm matrix polysaccharides cellulose and alginate both protect Pseudomonas putida mt-2 against reactive oxygen species generated under matric stress and copper exposure.

PubMed

Svenningsen, Nanna B; Martínez-García, Esteban; Nicolaisen, Mette H; de Lorenzo, Victor; Nybroe, Ole

2018-06-01

In natural environments most bacteria live in biofilms embedded in complex matrices of extracellular polymeric substances (EPS). This lifestyle is known to increase protection against environmental stress. Pseudomonas putida mt-2 harbours genes for the production of at least four different EPS polysaccharides, including alginate and cellulose. Little is known about the functional properties of cellulose, while alginate attenuates the accumulation of reactive oxygen species (ROS) caused by matric stress. By using mutants that are deficient in either alginate or cellulose production we show that even cellulose attenuates the accumulation of matric stress-induced ROS for cells in biofilms. Further, both cellulose and alginate attenuate ROS generated through exposure to copper. Interestingly, the two EPS polysaccharides protect cells in both liquid culture and in biofilms against ROS caused by matric stress, indicating that cellulose and alginate do not need to be produced as an integral part of the biofilm lifestyle to provide tolerance towards environmental stressors.

Modifying alginate with early embryonic extracellular matrix, laminin, and hyaluronic acid for adipose tissue engineering.

PubMed

Chen, Yo-Shen; Chen, Yen-Yu; Hsueh, Yu-Sheng; Tai, Hao-Chih; Lin, Feng-Huei

2016-03-01

Extracellular matrix provides both mechanistic and chemical cues that can influence cellular behaviors such as adhesion, migration, proliferation, and differentiation. In this study, a new material, HA-L-Alg, was synthesized by linking developmentally essential ECM constituents hyaluronic acid (HA) and laminin(L) to alginate (Alg). The fabrication of HA-L-Alg was confirmed by FTIR spectroscopy, and it was used to form 3D cell-carrying beads. HA-L-Alg beads had a steady rate of degradation and retained 63.25% of mass after 9 weeks. HA-L-Alg beads showed biocompatibility comparable to beads formed by Alg-only with no obvious cytotoxic effect on the embedded 3T3-L1 preadipocytes. HA-L-Alg encapsulated 3T3-L1 cells were found to have a higher proliferation rate over those in Alg-only beads. These cells also showed better differentiation capacity after 2 weeks of adipogenic induction within HA-L-Alg beads. These results support that HA-L-Alg facilitated cell survival and proliferation, as well as stimulated and maintained cell differentiation. Our results suggest that HA-L-Alg has a great clinical potential to be used as stem cell carrier for adipose tissue engineering. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 669-677, 2016. © 2015 Wiley Periodicals, Inc.

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

Identification of enzymes responsible for extracellular alginate depolymerization and alginate metabolism in Vibrio algivorus.

PubMed

Doi, Hidetaka; Tokura, Yuriko; Mori, Yukiko; Mori, Kenichi; Asakura, Yoko; Usuda, Yoshihiro; Fukuda, Hiroo; Chinen, Akito

2017-02-01

Alginate is a marine non-food-competing polysaccharide that has potential applications in biorefinery. Owing to its large size (molecular weight >300,000 Da), alginate cannot pass through the bacterial cell membrane. Therefore, bacteria that utilize alginate are presumed to have an enzyme that degrades extracellular alginate. Recently, Vibrio algivorus sp. SA2 T was identified as a novel alginate-decomposing and alginate-utilizing species. However, little is known about the mechanism of alginate degradation and metabolism in this species. To address this issue, we screened the V. algivorus genomic DNA library for genes encoding polysaccharide-decomposing enzymes using a novel double-layer plate screening method and identified alyB as a candidate. Most identified alginate-decomposing enzymes (i.e., alginate lyases) must be concentrated and purified before extracellular alginate depolymerization. AlyB of V. algivorus heterologously expressed in Escherichia coli depolymerized extracellular alginate without requiring concentration or purification. We found seven homologues in the V. algivorus genome (alyB, alyD, oalA, oalB, oalC, dehR, and toaA) that are thought to encode enzymes responsible for alginate transport and metabolism. Introducing these genes into E. coli enabled the cells to assimilate soluble alginate depolymerized by V. algivorus AlyB as the sole carbon source. The alginate was bioconverted into L-lysine (43.3 mg/l) in E. coli strain AJIK01. These findings demonstrate a simple and novel screening method for identifying polysaccharide-degrading enzymes in bacteria and provide a simple alginate biocatalyst and fermentation system with potential applications in industrial biorefinery.

Chitosan Enriched Three-Dimensional Matrix Reduces Inflammatory and Catabolic Mediators Production by Human Chondrocytes

PubMed Central

Oprenyeszk, Frederic; Sanchez, Christelle; Dubuc, Jean-Emile; Maquet, Véronique; Henrist, Catherine; Compère, Philippe; Henrotin, Yves

2015-01-01

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for 28 days either in chitosan-alginate beads or in alginate beads. The beads were formed by slowly passing dropwise either the chitosan 0.6%–alginate 1.2% or the alginate 1.2% solution through a syringe into a 102 mM CaCl2 solution. Beads were analyzed histologically after 28 days. Interleukin (IL)-6 and -8, prostaglandin (PG) E2, matrix metalloproteinases (MMPs), hyaluronan and aggrecan were quantified directly in the culture supernatant by specific ELISA and nitric oxide (NO) by using a colorimetric method based on the Griess reaction. Hematoxylin and eosin staining showed that chitosan was homogeneously distributed through the matrix and was in direct contact with chondrocytes. The production of IL-6, IL-8 and MMP-3 by chondrocytes significantly decreased in chitosan-alginate beads compared to alginate beads. PGE2 and NO decreased also significantly but only during the first three days of culture. Hyaluronan and aggrecan production tended to increase in chitosan-alginate beads after 28 days of culture. Chitosan-alginate beads reduced the production of inflammatory and catabolic mediators by OA chondrocytes and tended to stimulate the synthesis of cartilage matrix components. These particular effects indicate that chitosan-alginate beads are an interesting scaffold for chondrocytes encapsulation before transplantation to repair cartilage defects. PMID:26020773

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

Dried calcium alginate/magnetite spheres: a new support for chromatographic separations and enzyme immobilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

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, excellentmore » 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.« less

Dual crosslinked pectin-alginate network as sustained release hydrophilic matrix for repaglinide.

PubMed

Awasthi, Rajendra; Kulkarni, Giriraj T; Ramana, Malipeddi Venkata; de Jesus Andreoli Pinto, Terezinha; Kikuchi, Irene Satiko; Molim Ghisleni, Daniela Dal; de Souza Braga, Marina; De Bank, Paul; Dua, Kamal

2017-04-01

Repaglinide, an oral antidiabetic agent, has a rapid onset of action and short half-life of approximately 1h. Developing a controlled and prolonged release delivery system is required to maintain its therapeutic plasma concentration and to eliminate its adverse effects particularly hypoglycemia. The present study aimed to develop controlled release repaglinide loaded beads using sodium alginate and pectin with dual cross-linking for effective control of drug release. The prepared beads were characterized for size, percentage drug entrapment efficiency, in vitro drug release and the morphological examination using scanning electron microscope. For the comparative study, the release profile of a marketed conventional tablet of repaglinide (Prandin ® tablets 2mg, Novo Nordisk) was determined by the same procedure as followed for beads. The particle size of beads was in the range of 698±2.34-769±1.43μm. The drug entrapment efficiency varied between 55.24±4.61 to 82.29±3.42%. The FTIR results suggest that there was no interaction between repaglinide and excipients. The XRD and DSC results suggest partial molecular dispersion and amorphization of the drug throughout the system. These results suggest that repaglinide did not dissolve completely in the polymer composition and seems not to be involved in the cross-linking reaction. The percent drug release was decreased with higher polymer concentrations. In conclusion, the developed beads could enhance drug entrapment efficiency, prolong the drug release and enhance bioavailability for better control of diabetes. Copyright © 2017 Elsevier B.V. All rights reserved.

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 %.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cryopreservation on a cryo-plate of Arundina graminifolia protocorms, dehydrated with silica gel and drying beads.

PubMed

Cordova, L B; Thammasiri, K

2016-01-01

There are various methods for the cryopreservation of plant material, with each biological specimen potentially requiring protocol optimization to maximize success. The aim of this study is to compare droplet-vitrification, encapsulation-dehydration, and the cryo-plate method for cryopreservation of protocorms of the orchid Arundina graminifolia, using silica gel and drying beads as the desiccation materials. The cryo-plate method included preculture of protocorms, developed from seeds, placed on aluminium cryo-plates and embedded in alginate gel. Cryo-plates were surface dried using sterile filter paper, placed in Petri dishes containing 50 g silica gel or 30 g drying beads in a laminar air-flow cabinet. Specimens on cryo-plates were dehydrated to 25 % moisture content, placed into 2 mL cryotubes and plunged directly into liquid nitrogen for 1 d. For cryopreservation, the cryo-plate method, involving dehydration with 30 g drying beads gave the highest regrowth (77 %), followed by the encapsulation-dehydration method with 30 g drying beads (64 % regrowth) and the droplet-vitrification method, following exposure to PVS2 solution for 20 min (33 % regrowth). Regrowth of cryopreserved protocorms using the cryo-plate method was rapid with the highest survival and regrowth.

Effects of cryopreservation and hypothermic storage on cell viability and enzyme activity in recombinant encapsulated cells overexpressing alpha-L-iduronidase.

PubMed

Mayer, Fabiana Quoos; Baldo, Guilherme; de Carvalho, Talita Giacomet; Lagranha, Valeska Lizzi; Giugliani, Roberto; Matte, Ursula

2010-05-01

Here, we show the effects of cryopreservation and hypothermic storage upon cell viability and enzyme release in alginate beads containing baby hamster kidney cells overexpressing alpha-L-iduronidase (IDUA), the enzyme deficient in mucopolysaccharidosis type I. In addition, we compared two different concentrations of alginate gel (1% and 1.5%) in respect to enzyme release from the beads and their shape and integrity. Our results indicate that in both alginate concentrations, the enzyme is released in lower amounts compared with nonencapsulated cells. Alginate 1% beads presented increased levels of IDUA release, although this group presented more deformities when compared with alginate 1.5% beads. Importantly, both encapsulated groups presented higher cell viability after long cryopreservation period and hypothermic storage. In addition, alginate 1.5% beads presented higher enzyme release after freezing protocols. Taken together, our findings suggest a benefic effect of alginate upon cell viability and functionality. These results may have important application for treatment of both genetic and nongenetic diseases using microencapsulation-based artificial organs.

Enhanced production of alkaline thermostable keratinolytic protease from calcium alginate immobilized cells of thermoalkalophilic Bacillus halodurans JB 99 exhibiting dehairing activity.

PubMed

Shrinivas, Dengeti; Kumar, Raghwendra; Naik, G R

2012-01-01

The thermoalkalophilic Bacillus halodurans JB 99 cells known for production of novel thermostable alkaline keratinolytic protease were immobilized in calcium alginate matrix. Batch and repeated batch cultivation using calcium alginate immobilized cells were studied for alkaline protease production in submerged fermentation. Immobilized cells with 2.5% alginate and 350 beads/flask of initial cell loading showed enhanced production of alkaline protease by 23.2% (5,275 ± 39.4 U/ml) as compared to free cells (4,280 ± 35.4 U/ml) after 24 h. In the semicontinuous mode of cultivation, immobilized cells under optimized conditions produced an appreciable level of alkaline protease in up to nine cycles and reached a maximal value of 5,975 U/ml after the seventh cycle. The enzyme produced from immobilized cells efficiently degraded chicken feathers in the presence of a reducing agent which can help the poultry industry in the management of keratin-rich waste and obtaining value-added products.

* Hypoxia for Mesenchymal Stem Cell Expansion and Differentiation: The Best Way for Enhancing TGFß-Induced Chondrogenesis and Preventing Calcifications in Alginate Beads.

PubMed

Henrionnet, Christel; Liang, Gai; Roeder, Emilie; Dossot, Manuel; Wang, Hui; Magdalou, Jacques; Gillet, Pierre; Pinzano, Astrid

2017-09-01

We examined the respective influence of a sequential or a continuous hypoxia during expansion and transforming growth factor beta 1-driven chondrogenic differentiation of human bone marrow mesenchymal stem cells (MSCs). The differentiation was performed within alginate beads, a classical tool for the implantation of MSCs within the joint. The standard normoxic 2D (expansion) and 3D (differentiation) MSCs cultures served as reference. To determine the quality of chondrogenesis, we analyzed typical markers such as type II and X collagens, SOX9, COMP, versican, and aggrecan mRNAs using polymerase chain reaction and we assessed the production of type II collagen and hypoxia-inducible factor (HIF)-1α by histological stainings. We simultaneously assessed the expression of osteogenic mRNAs (Alkaline Phosphatase, RUNX2, and Osteocalcin) and the presence of micro-calcifications by Alizarin red and Raman spectroscopy. Chondrogenic differentiation is clearly improved by hypoxia in 3D. Best results were obtained when the entire process, that is, 2D expansion and 3D differentiation, was performed under continuous 5% hypoxic condition. In addition, no calcification (hydroxyapatite, proved by RAMAN) was observed after 2D hypoxic expansion even in the case of a normoxic differentiation, in contrast with controls. Finally, a better chondrogenic differentiation of human MSCs is achieved when a reduced oxygen tension is applied during both expansion and differentiation times, avoiding in vitro osteogenic commitment of cells and subsequently the calcification deposition.

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

Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water.

PubMed

Jin, Jing; Yang, Lihua; Chan, Sidney M N; Luan, Tiangang; Li, Yan; Tam, Nora F Y

2011-01-30

The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency. Copyright © 2010 Elsevier B.V. All rights reserved.

Alginate: A Versatile Biomaterial to Encapsulate Isolated Ovarian Follicles.

PubMed

Vanacker, Julie; Amorim, Christiani A

2017-07-01

In vitro culture of ovarian follicles isolated or enclosed in ovarian tissue fragments and grafting of isolated ovarian follicles represent a potential alternative to restore fertility in cancer patients who cannot undergo cryopreservation of embryos or oocytes or transplantation of frozen-thawed ovarian tissue. In this regard, respecting the three-dimensional (3D) architecture of isolated follicles is crucial to maintaining their proper follicular physiology. To this end, alginate hydrogel has been widely investigated using follicles from numerous animal species, yielding promising results. The goal of this review is therefore to provide an overview of alginate applications utilizing the biomaterial as a scaffold for 3D encapsulation of isolated ovarian follicles. Different methods of isolated follicle encapsulation in alginate are discussed in this review, as its use of 3D alginate culture systems as a tool for in vitro follicle analysis. Possible improvements of this matrix, namely modification with arginine-glycine-aspartic acid peptide or combination with fibrin, are also summarized. Encouraging results have been obtained in different animal models, and particularly with isolated follicles encapsulated in alginate matrices and grafted to mice. This summary is designed to guide the reader towards development of next-generation alginate scaffolds, with enhanced properties for follicle encapsulation.

Transplantation of an alginate-matrigel matrix containing isolated ovarian cells: first step in developing a biodegradable scaffold to transplant isolated preantral follicles and ovarian cells.

PubMed

Vanacker, Julie; Luyckx, Valérie; Dolmans, Marie-Madeleine; Des Rieux, Anne; Jaeger, Jonathan; Van Langendonckt, Anne; Donnez, Jacques; Amorim, Christiani A

2012-09-01

For women diagnosed with leukemia, transplantation of cryopreserved ovarian tissue after disease remission is not advisable. Therefore, to restore fertility in these patients, we aim to develop a biodegradable artificial ovary that offers an environment where isolated follicles and ovarian cells (OCs) can survive and grow. Four NMRI mice were ovariectomized and their ovaries used to isolate OCs. Groups of 50,000 OCs were embedded in an alginate-matrigel matrix for further fixation (fresh controls), one week of in vitro culture (IVC) or heterotopic autografting. OC proliferation (Ki67), apoptosis (TUNEL), scaffold degradation, vessel formation (CD34) and inflammation (CD45) were analyzed. Ki67-positive OCs were found in 2.3%, 9.0% and 15.5% cells of cases in fresh, IVC and grafted beads respectively, while cells were TUNEL-positive in 0%, 1.5% and 6.9% of cases. After IVC or grafting, the beads degraded, losing their original round aspect, and infiltrating blood capillaries could be observed in the grafted beads. CD34-positive cells and 22% CD45-positive cells were found around and inside the matrix. In conclusion, our results demonstrate that an alginate-based matrix is a promising proposition to graft isolated OCs. After transplantation, this matrix was able to degrade, allowed vascularization and elicited a low inflammatory response. Copyright © 2012 Elsevier Ltd. All rights reserved.

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 is...

A novel alginate-encapsulated system to study biological response to critical-sized wear particles of UHMWPE loaded with alendronate sodium.

PubMed

Liu, Yumei; Shi, Feng; Bo, Lin; Zhi, Wei; Weng, Jie; Qu, Shuxin

2017-10-01

The aim of this study was to develop a novel alginate-encapsulated system (Alg beads) to investigate the cell response to critical-sized wear particles of ultra-high molecular weight polyethylene loaded with alendronate sodium (UHMWPE-ALN), one of the most effective drugs to treat bone resorption in clinic. The extrusion method was used to prepare Alg beads encapsulating rat calvarial osteoblasts (RCOs) and critical-sized UHMWPE-ALN wear particles with spherical morphology and uniform size. The morphology, permeability and stability of Alg beads were characterized. The proliferation, ALP activity, cell apoptosis and distribution of live/dead RCOs co-cultured with wear particles in Alg beads were evaluated. RCOs and critical-sized UHMWPE-ALN wear particles distributed evenly and contacted efficiently in Alg beads. Alg beads were both permeable to trypsin and BSA, while the smaller the molecular was, the larger the diffuse was. The proliferation of RCOs in Alg beads increased with time, which indicated that Alg beads provided suitable conditions for cell culture. The long-term stability of Alg beads indicated the possibility for the longer time of co-cultured cells with wear particles. Critical-sized UHMWPE-ALN and UHMWPE wear particles both inhibited the proliferation and differentiation of RCOs, and induced the apoptosis of RCOs encapsulated in Alg beads. However, these effects could be significantly alleviated by the ALN released from the critical-sized UHMWPE-ALN wear particles. The present results suggested that this novel-developed co-culture system was feasible to evaluate the cell response to critical-sized UHMWPE-ALN wear particles for a longer time. Copyright © 2017 Elsevier B.V. All rights reserved.

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 by...

Thermodynamic and kinetic studies on pectinase extracted from Aspergillus aculeatus: Free and immobilized enzyme entrapped in alginate beads.

PubMed

de Oliveira, Rodrigo Lira; da Silva, Osmar Soares; Converti, Attilio; Porto, Tatiana Souza

2018-05-01

The kinetics and thermodynamics of Aspergillus aculeatus pectinase, either free or immobilized in alginate beads, were investigated. Pectinase immobilization ensured an enzyme immobilization yield of 59.71%. The irreversible denaturation of pectinase in both preparations was evaluated at temperatures ranging from 30 to 60 °C. When temperature was raised, the first-order thermal denaturation constant increased from 0.0011 to 0.0231 min -1 for the free enzyme and from 0.0017 to 0.0700 min -1 for the immobilized one, respectively. The results of residual activity tests enabled us to estimate, for denaturation of both free and immobilized pectinase, the activation energy (E ⁎ d  = 85.1 and 101.6 kJ·mol -1 ), enthalpy (82.59 ≤ ΔH ⁎ d  ≤ 82.34 kJ·mol -1 and 99.11 ≤ ΔH ⁎ d  ≤ 98.86 kJ·mol -1 ), entropy (-63.26 ≤ ΔS ⁎ d  ≤ -63.85 J·mol -1 ·K -1 and -5.50 ≤ ΔS ⁎ d  ≤ -5.23 J·mol -1 ·K -1 ) and Gibbs free energy (101.8 ≤ ΔG ⁎ d  ≤ 104.7 kJ·mol -1 and 100.6 ≤ ΔG ⁎ d  ≤ 102.0 kJ·mol -1 ). The integral activity of a continuous system using the free and immobilized enzyme was also predicted, whose results indicated a satisfactory enzyme long-term thermostability in both preparations at temperatures commonly used to clarify juice. These results suggest that both free and immobilized pectinase from A. aculeatus may be profitably exploited in future food industrial applications, with special concern to the immobilized enzyme because of its reusability. Copyright © 2018 Elsevier B.V. All rights reserved.

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 the...

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 is...

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.

Co-delivery of cisplatin and doxorubicin from calcium phosphate beads/matrix scaffolds for osteosarcoma therapy.

PubMed

Hess, Ulrike; Shahabi, Shakiba; Treccani, Laura; Streckbein, Philipp; Heiss, Christian; Rezwan, Kurosch

2017-08-01

Bone substitute materials with a controlled drug release ability can fill cavities caused by the resection of bone tumours and thereby combat any leftover bone cancer cells. The combined release of different cytostatics seems to enhance their toxicity. In this study, calcium phosphate beads and matrix scaffolds are combined for a long-term co-delivery of cis-diamminedichloroplatinum (cisplatin, CDDP) and doxorubicin hydrochloride (DOX) as clinical relevant model drugs. Tricalcium phosphate/alginate beads as additional drug carrier are produced by droplet extrusion with ionotropic gelation and incorporated in scaffold matrix by freeze gelation without sintering. CDDP shows a short burst release while DOX has a continuous release measurable over the entire study period of 40days. Drug release from matrix is decreased by ~30% compared to release from beads. Nevertheless, all formulations follow the Korsmeyer-Peppas release kinetic model and show Fickian diffusion. Cytotoxic activity was conducted on MG-63 osteosarcoma cells after 1, 4, and 7days with WST-1 cell viability assay. Co-loaded composites enhance activity towards MG-63 cells up to ~75% toxicity while reducing the released drug quantity. The results suggest that co-loaded beads/matrix scaffolds are highly promising for osteosarcoma therapy due to synergistic effects over a long period of more than a month. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Alginate Lyase (AlgL) Activity Is Required for Alginate Biosynthesis in Pseudomonas aeruginosa

PubMed Central

Albrecht, Mark T.; Schiller, Neal L.

2005-01-01

To determine whether AlgL's lyase activity is required for alginate production in Pseudomonas aeruginosa, an algLΔ::Gmr mutant (FRD-MA7) was created. algL complementation of FRD-MA7 restored alginate production, but algL constructs containing mutations inactivating lyase activity did not, demonstrating that the enzymatic activity of AlgL is required for alginate production. PMID:15901714

Deterministic bead-in-droplet ejection utilizing an integrated plug-in bead dispenser for single bead-based applications

NASA Astrophysics Data System (ADS)

Kim, Hojin; Choi, In Ho; Lee, Sanghyun; Won, Dong-Joon; Oh, Yong Suk; Kwon, Donghoon; Sung, Hyung Jin; Jeon, Sangmin; Kim, Joonwon

2017-04-01

This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead-encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin-biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules.

Deterministic bead-in-droplet ejection utilizing an integrated plug-in bead dispenser for single bead-based applications.

PubMed

Kim, Hojin; Choi, In Ho; Lee, Sanghyun; Won, Dong-Joon; Oh, Yong Suk; Kwon, Donghoon; Sung, Hyung Jin; Jeon, Sangmin; Kim, Joonwon

2017-04-10

This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead-encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin-biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules.

Calcium alginate particles for the combined delivery of platelet lysate and vancomycin hydrochloride in chronic skin ulcers.

PubMed

Mori, Michela; Rossi, Silvia; Bonferoni, Maria Cristina; Ferrari, Franca; Sandri, Giuseppina; Riva, Federica; Del Fante, Claudia; Perotti, Cesare; Caramella, Carla

2014-01-30

The aim of the present work was the development of a powder formulation for the combined delivery of platelet lysate and of a model antibiotic drug, vancomycin hydrochloride (VCM), in chronic skin ulcers. Calcium alginate particles were prepared by freeze-drying beads obtained by ionic gelation method. The experimental conditions adopted permitted the complete loading of VCM and of PDGF AB, the growth factor chosen as representative of those contained in PL. Such particles where able to absorb PBS (mimicking wound exudate), to form a gel and to modulate the release of VCM and of PDGF AB. They are characterized by enhancement properties of human fibroblast proliferation due to PL presence. In particular, PL, when loaded in alginate particles, was able not only to increase the number of viable cells, but also the number of cells in proliferative phase. Such properties were comparable to those of fresh PL indicating the capability of calcium alginate particles to load PL bioactive substances without altering their activity. The formulation developed is characterized by an easier and a less painful administration with respect to traditional gauzes and semisolid preparations and permits the loading in the same dosage form of active substances of different nature avoiding eventual incompatibility problems. Copyright © 2013 Elsevier B.V. All rights reserved.

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 brown...

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 brown...

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

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 algae...

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 algae...

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 algae...

21 CFR 184.1187 - Calcium alginate.

Code of Federal Regulations, 2012 CFR

2012-04-01

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

21 CFR 184.1187 - Calcium alginate.

Code of Federal Regulations, 2013 CFR

2013-04-01

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

Physicochemical properties of marine collagen-alginate biomaterial

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-11-01

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

Development of alginate-based aggregate inoculants of Methylobacterium sp. and Azospirillum brasilense tested under in vitro conditions to promote plant growth.

PubMed

Joe, M M; Saravanan, V S; Islam, M R; Sa, T

2014-02-01

To develop co-aggregated bacterial inoculant comprising of Methylobacterium oryzae CBMB20/Methylobacterium suomiense CBMB120 strains with Azospirillum brasilense (CW903) strain and testing their efficiency as inoculants for plant growth promotion (PGP). Biofilm formation and co-aggregation efficiency was studied between A. brasilense CW903 and methylobacterial strains M. oryzae CBMB20 and M. suomiense CBMB120. Survival and release of these co-aggregated bacterial strains entrapped in alginate beads were assessed. PGP attributes of the co-aggregated bacterial inoculant were tested in tomato plants under water-stressed conditions. Results suggest that the biofilm formation efficiency of the CBMB20 and CBMB120 strains increased by 15 and 34%, respectively, when co-cultivated with CW903. Co-aggregation with CW903 enhanced the survivability of CBMB20 strain in alginate beads. Water stress index score showed least stress index in plants inoculated with CW903 and CBMB20 strains maintained as a co-aggregated inoculant. This study reports the development of co-aggregated cell inoculants containing M. oryzae CBMB20 and A. brasilense CW903 strains conferred better shelf life and stress abatement in inoculated tomato plants. These findings could be extended to other PGP bacterial species to develop multigeneric bioinoculants with multiple benefits for various crops. © 2013 The Society for Applied Microbiology.

Heterogeneous immunoassays using magnetic beads on a digital microfluidic platform.

PubMed

Sista, Ramakrishna S; Eckhardt, Allen E; Srinivasan, Vijay; Pollack, Michael G; Palanki, Srinivas; Pamula, Vamsee K

2008-12-01

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels. Immunoassays on a digital microfluidic platform require the following basic operations: bead attraction, bead washing, bead retention, and bead resuspension. Several parameters such as magnetic field strength, pull force, position, and buffer composition were studied for effective bead operations. Dilution-based washing of magnetic beads was demonstrated by immobilizing the magnetic beads using a permanent magnet and splitting the excess supernatant using electrowetting. Almost 100% bead retention was achieved after 7776-fold dilution-based washing of the supernatant. Efficient resuspension of magnetic beads was achieved by transporting a droplet with magnetic beads across five electrodes on the platform and exploiting the flow patterns within the droplet to resuspend the beads. All the magnetic-bead droplet operations were integrated together to generate standard curves for sandwich heterogeneous immunoassays on human insulin and interleukin-6 (IL-6) with a total time to result of 7 min for each assay.

Heterogeneous Immunoassays Using Magnetic beads On a Digital Microfluidic Platform

PubMed Central

Sista, Ramakrishna S.; Eckhardt, Allen E.; Srinivasan, Vijay; Pollack, Michael G.; Palanki, Srinivas; Pamula, Vamsee K.

2009-01-01

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels. Immunoassays on a digital microfluidic platform require the following basic operations: bead attraction, bead washing, bead retention, and bead resuspension. Several parameters such as magnetic field strength, pull force, position, and buffer composition were studied for effective bead operations. Dilution-based washing of magnetic beads was demonstrated by immobilizing the magnetic beads using a permanent magnet and splitting the excess supernatant using electrowetting. Almost 100% bead retention was achieved after 7776 fold dilution-based washing of the supernatant. Efficient resuspension of magnetic beads was achieved by transporting a droplet with magnetic beads across five electrodes on the platform and exploiting the flow patterns within the droplet to resuspend the beads. All the magnetic-bead droplet operations were integrated together to generate standard curves for sandwich heterogeneous immunoassays on Human Insulin and Interleukin-6 (IL-6) with a total time to result of seven minutes for each assay. PMID:19023486

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

Survival of human pre-antral follicles after cryopreservation of ovarian tissue, follicular isolation and in vitro culture in a calcium alginate matrix.

PubMed

Amorim, Christiani A; Van Langendonckt, Anne; David, Anu; Dolmans, Marie-Madeleine; Donnez, Jacques

2009-01-01

Ovarian tissue cryopreservation is a promising technique to safeguard fertility in cancer patients. However, in some types of cancer, there is a risk of transmitting malignant cells present in the cryopreserved tissue. To avoid such a risk, pre-antral follicles could be isolated from ovarian tissue and grown in vitro. On the basis of this assumption, the aim of our study was to investigate in vitro survival and growth of pre-antral follicles after cryopreservation of ovarian tissue and follicular isolation, followed by encapsulation in alginate beads. Ovarian biopsies from four patients were frozen and thawed. Pre-antral follicles were then isolated and embedded in an alginate matrix before in vitro culture for 7 days. Small pre-antral follicles (42.98 +/- 9.06 microm) from frozen-thawed tissue can survive and develop after enzymatic isolation and in vitro culture. A total of 159 follicles were incubated in a three-dimensional system (alginate hydrogel) and, after 7 days, all of them showed an increase in size (final size 56.73 +/- 13.10 microm). The survival rate of the follicles was 90% (oocyte and all granulosa cells viable). Our preliminary results indicate that alginate hydrogels may be a suitable system for in vitro culture of isolated human pre-antral follicles. However, more studies are required to establish whether follicular morphology and functionality can be maintained using this matrix.

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 generally...

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 generally...

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 generally...

21 CFR 582.7187 - Calcium alginate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

21 CFR 582.7187 - Calcium alginate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

21 CFR 582.7187 - Calcium alginate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

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

NASA Astrophysics Data System (ADS)

Mulia, Kamarza; Halimah, Nur; Krisanti, Elsa

2017-03-01

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

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 as...

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 as...

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 as...

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 as...

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 as...

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

Nickel adsorption by magnetic alginate microcapsules containing an extractant.

PubMed

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

2006-05-01

The adsorption of heavy metals on biomaterials was investigated by studying the potential of alginate microcapsules containing an extractant (Cyanex 272) and magnetic nanoparticles (gamma-Fe2O3) for the adsorption of nickel (II) from aqueous solutions. A two-stage kinetics behaviour was observed with 70% of the maximum sorption capacity achieved within 8 h. An increase in nickel removal with increase in pH occurred, the maximum uptake capacity being around 0.42 mmol g-1 at pH 8. The adsorption isotherm (pH about 5.3) was obtained in a wide range of initial nickel concentrations; the experimental data were fitted by a Langmuir model and the qmax value was estimated to be 0.52 mmol g-1. Moreover, including magnetic particles in the microcapsules allowed easy isolation of the beads from the aqueous solutions after the sorption process. Magnetic microcapsules are then suitable for the development of efficient biosorbents for removal and recovery of heavy metals from wastewater using magnetic separation.

Generation of a scaffold free cartilage-like implant from a small amount of starting material.

PubMed

Stoddart, M J; Ettinger, L; Häuselmann, H J

2006-01-01

An autologous cellular based treatment of a traumatic cartilage injury requires a procedure whereby a biopsy of healthy cartilage is removed from the patient and the cells isolated and expanded by monolayer passage. This increases the cell number to required levels but also leads to a de-differentiation of the cells. We aim to produce a scaffold-free, de-novo implant from a biopsy of cartilage. Bovine chondrocytes were isolated from a small biopsy and expanded. The chondrocytic phenotype of the monolayer expanded cells was recovered during a period of culture in alginate and the effect of factors such as IGF1, TFGbeta1 and dexamethasone was investigated. During the alginate culture period a pre-treatment with IGF1 and dexamethasone was shown to have little effect. IGF1 however increased the glycosaminoglycan/DNA (GAG/DNA) content on day 14 to 84.95+/-5 ng/ng compared with 37.3+/-1.8 ng/ng in the controls (P<0.001). 35S labeling demonstrated an increased GAG synthesis in the presence of IGF1 (P<0.001). IGF1 also induced a increase of DNA content 1383+/-314 ng/bead compared to 512+/-19 ng/bead in the controls (P<0.001). The cells were released from the alginate and cultured in a silicon mould for a further 14 days to obtain a three dimensional implant. Releasing the cells from the alginate and casting in a mould produced an implant of defined shape which contained no foreign material. After 31 days of culture the implants contained 152.4+/-13.14 ng/ng GAG/DNA and 42.93+/-10.23 ng/ng collagen II. We believe alginate released chondrocytes provide a real alternative to artificial scaffolds.

EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

PubMed

Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

2016-05-01

Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure.

Hydrodynamic Torques and Rotations of Superparamagnetic Bead Dimers

NASA Astrophysics Data System (ADS)

Pease, Christopher; Etheridge, J.; Wijesinghe, H. S.; Pierce, C. J.; Prikockis, M. V.; Sooryakumar, R.

Chains of micro-magnetic particles are often rotated with external magnetic fields for many lab-on-a-chip technologies such as transporting beads or mixing fluids. These applications benefit from faster responses of the actuated particles. In a rotating magnetic field, the magnetization of superparamagnetic beads, created from embedded magnetic nano-particles within a polymer matrix, is largely characterized by induced dipoles mip along the direction of the field. In addition there is often a weak dipole mop that orients out-of-phase with the external rotating field. On a two-bead dimer, the simplest chain of beads, mop contributes a torque Γm in addition to the torque from mip. For dimers with beads unbound to each other, mop rotates individual beads which generate an additional hydrodynamic torque on the dimer. Whereas, mop directly torques bound dimers. Our results show that Γm significantly alters the average frequency-dependent dimer rotation rate for both bound and unbound monomers and, when mop exceeds a critical value, increases the maximum dimer rotation frequency. Models that include magnetic and hydrodynamics torques provide good agreement with the experimental findings over a range of field frequencies.

Optimisation of nutritional requirements for dopamine synthesis by calcium alginate-entrapped mutant strain of Aspergillus oryzae EMS-6.

PubMed

Ali, Sikander; Nawaz, Wajeeha

2017-02-01

The optimisation of nutritional requirements for dopamine (DA) synthesis by calcium alginate-entrapped mutant variant of Aspergillus oryzae EMS-6 using submerged fermentation technique was investigated. A total of 13 strains were isolated from soil. Isolate I-2 was selected as a better producer of DA and improved by exposing with ethyl methylsulphonate (EMS). EMS-6 was selected as it exhibited 43 μg/mL DA activity. The mutant variable was further treated with low levels of l-cysteine HCl to make it resistant against diversion and environmental stress. The conidiospores of mutant variant were entrapped in calcium alginate beads for stable product formation. EMS-6 gave maximum DA activity (124 μg/mL) when supplemented with 0.1% peptone and 0.2% sucrose, under optimised parameters viz. pH 3, temperature of 55 °C and incubation time of 70 min. The study involves the high profile of DA activity and is needed, as DA is capable to control numerous neurogenic disorders.

Enzymatic detection of As(III) in aqueous solution using alginate immobilized pumpkin urease: optimization of process variables by response surface methodology.

PubMed

Talat, Mahe; Prakash, Om; Hasan, S H

2009-10-01

Urease immobilized on alginate was utilized to detect and quantify As(3+) in aqueous solution. Urease from the seeds of pumpkin (vegetable waste) was purified to apparent homogeneity by heat treatment and gel filtration (Sephadex G-200). Further enzyme was entrapped in 3.5% alginate beads. Urea hydrolysis by enzyme revealed a clear dependence on the concentration and interaction time of As(3+). The process variables effecting the quantitation of As(3+) was investigated using central composite design with Minitab 15 software. The predicted results were found in good agreement (R(2)=96.71%) with experimental results indicating the applicability of proposed model. The multiple regression analysis and ANOVA showed that enzyme activity decreased with increase of As(3+) concentration and interaction time. 3D plot and contour plot between As(3+) concentration and interaction time was helpful to predict residual activity of enzyme for a particular As(3+) at a particular time.

Three-bead steering microswimmers

NASA Astrophysics Data System (ADS)

Rizvi, Mohd Suhail; Farutin, Alexander; Misbah, Chaouqi

2018-02-01

The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with active oscillatory forces being applied on the beads to generate self-propulsion. We have extended this linear microswimmer configuration to a triangular geometry where the three beads are connected by three identical springs in an equilateral triangular manner. The active forces acting on each spring can lead to autonomous steering motion; i.e., allowing the swimmer to move along arbitrary paths. We explore the microswimmer dynamics analytically and pinpoint its rich character depending on the nature of the active forces. The microswimmers can translate along a straight trajectory, rotate at a fixed location, as well as perform a simultaneous translation and rotation resulting in complex curved trajectories. The sinusoidal active forces on the three springs of the microswimmer contain naturally four operating parameters which are more than required for the steering motion. We identify the minimal operating parameters which are essential for the motion of the microswimmer along any given arbitrary trajectory. Therefore, along with providing insights into the mechanics of the complex motion of the natural and artificial microswimmers, the triangular three-bead microswimmer can be utilized as a model for targeted drug delivery systems and autonomous underwater vehicles where intricate trajectories are involved.

Efficient functionalization of alginate biomaterials.

PubMed

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

2016-02-01

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

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

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

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

PubMed Central

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

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

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 of...

Enzyme immobilization in novel alginate-chitosan core-shell microcapsules.

PubMed

Taqieddin, Ehab; Amiji, Mansoor

2004-05-01

Alginate-chitosan core-shell microcapsules were prepared in order to develop a biocompatible matrix for enzyme immobilization, where the protein is retained either in a liquid or solid core and the shell allows permeability control over substrates and products. The permeability coefficients of different molecular weight compounds (vitamin B2, vitamin B12, and myoglobin) were determined through sodium tripolyphosphate (Na-TPP)-crosslinked chitosan membrane. The microcapsule core was formed by crosslinking sodium alginate with either calcium or barium ions. The crosslinked alginate core was uniformly coated with a chitosan layer and crosslinked with Na-TPP. In the case of calcium alginate, the phosphate ions of Na-TPP were able to extract the calcium ions from alginate and liquefy the core. A model enzyme, beta-galactosidase, was immobilized in the alginate core and the catalytic activity was measured with o-nitrophenyl-beta-D-galactopyranoside (ONPG). Change in the activity of free and immobilized enzyme was determined at three different temperatures. Na-TPP crosslinked chitosan membranes were found to be permeable to solutes of up to 17,000Da molecular weight. The enzyme loading efficiency was higher in the barium alginate core (100%) as compared to the calcium alginate core (60%). The rate of ONPG conversion to o-nitrophenol was faster in the case of calcium alginate-chitosan microcapsules as compared to barium alginate-chitosan microcapsules. Barium alginate-chitosan microcapsules, however, did improve the stability of the enzyme at 37 degrees C relative to calcium alginate-chitosan microcapsules or free enzyme. This study illustrates a new method of enzyme immobilization for biotechnology applications using liquid or solid core and shell microcapsule technology.

Production of D-tagatose, a functional sweetener, utilizing alginate immobilized Lactobacillus fermentum CGMCC2921 cells.

PubMed

Xu, Zheng; Li, Sha; Fu, Fenggen; Li, Guixiang; Feng, Xiaohai; Xu, Hong; Ouyang, Pingkai

2012-02-01

D-tagatose is a ketohexose that can be used as a novel functional sweetener in foods, beverages, and dietary supplements. This study was aimed at developing a high-yielding D-tagatose production process using alginate immobilized Lactobacillus fermentum CGMCC2921 cells. For the isomerization from D-galactose into D-tagatose, the immobilized cells showed optimum temperature and pH at 65 °C and 6.5, respectively. The alginate beads exhibited a good stability after glutaraldehyde treatment and retained 90% of the enzyme activity after eight cycles (192 h at 65 °C) of batch conversion. The addition of borate with a molar ratio of 1.0 to D-galactose led to a significant enhancement in the D-tagatose yield. Using commercial β-galactosidase and immobilized L. fermentum cells, D-tagatose was successfully obtained from lactose after a two-step biotransformation. The relatively high conversion rate and productivity from D-galactose to D-tagatose of 60% and 11.1 g l⁻¹ h⁻¹ were achieved in a packed-bed bioreactor. Moreover, lactobacilli have been approved as generally recognized as safe organisms, which makes this L. fermentum strain an attracting substitute for recombinant Escherichia coli cells among D-tagatose production progresses.

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

2015-07-24

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.

Micro-Encapsulated Porphyrins and Phthalocyanines - New Formulations in Photodynamic Therapy

NASA Astrophysics Data System (ADS)

Ion, R. M.

2017-06-01

Photodynamic therapy (PDT), as an innovative method for cancer tretament is based on a concerted action of some drugs, called sensitizers, which generate reactive oxygen species via a photochemical mechanism, leading to cellular necrosis or apoptosis. The present work aims at loading some sensitizers, as porphyrins (P) and phthalocyanines (Pc) into alginate particles. Particles were prepared by dropping alginate into an aqueous solution containing P or Pc and CaCl2, which allows the formation of particles through ionic crosslinking. It was obtained P or Pc loaded alginate beads with an average diameter of about 100 μm. For these systems, this paper analyses the spectroscopic properties, encapsulation into microcapsules, controlled releasing action and their photosensitizer capacity (singlet oxygen generation).

Raman probing of molecular interactions of alginate biopolymers with cells

NASA Astrophysics Data System (ADS)

Chourpa, Igor; Carpentier, Philippe; Maingault, Philippe; Fetissoff, Franck; Dubois, Pierre

2000-05-01

The biological polymers extracted from brown algae, alginates, are novel materials in biotechnology and biomedicine. Their ability to form viscous gels is used to immobilize or encapsulate yeast, enzymes, living cells and drugs. Calcium-alginate fibers are extensively used in wound dressings since exhibit antihaemostatic and healing properties. The problem with alginate-made dressings in surgery is their slow biodegradability: if entrapped within tissues, they can induce a local cellular recruitment with an inflammatory response contemporaneous to the resorption phase. In part, this problem is a consequence of poor solubility of the calcium alginates in water. Although calcium alginate fibers can exchange calcium ions with sodium ions from the wound exudate to create a calcium/sodium alginate fibers, the residual alginates are thought to be not totally degradable in vivo. Rapid and non- destructive characterization of series of the crude alginates and calcium alginate fibers has been performed using Raman spectroscopy with near IR excitation. Study of structural organization of the polymeric chains within calcium alginate fibers have been previously reported as made by confocal Raman multispectral imaging (CRMSI) in visible. Here, the Raman approach has been used to monitor the ion exchange reactions for different types of alginates and their salts in vitro. For in vivo evaluation, histological sections of alginate-treated rat tissue have been analyzed by light microscopy and CRMSI. The in vitro Raman modeling and the histochemical mapping were a necessary precursor for application of the Raman microprobe to follow in a non-invasive way the alginate-cell molecular interactions in rat tissue.

From the one-bead-one-compound concept to one-bead-one-reactor.

PubMed

Marani, Mariela M; Paradís-Bas, Marta; Tulla-Puche, Judit; Côté, Simón; Camperi, Silvia A; Cascone, Osvaldo; Albericio, Fernando

2007-01-01

The one-bead-one-compound method gives access to millions of compounds that can be screened directly on the bead. Although characterization techniques are increasingly potent and reliable, problems can still be encountered in deciphering the sequence of the active compound because of sensitiveness or manipulation of the bead. ChemMatrix, a totally PEG-based resin, has resolved the synthesis of peptides of outstanding difficulty. Like other PEG-based resins, it permits on-bead screening because of its compatibility in aqueous media and has the further advantage of having a high loading, comparable to polystyrene resins. ChemMatrix beads previously swelled in water can be nicely divided into four parts that can be characterized using different analytical techniques or just stored for safety or for further testing. The four bead parts show high homogeneity and can thus be considered to be replicas.

NIST/ISAC standardization study: variability in assignment of intensity values to fluorescence standard beads and in cross calibration of standard beads to hard dyed beads.

PubMed

Hoffman, Robert A; Wang, Lili; Bigos, Martin; Nolan, John P

2012-09-01

Results from a standardization study cosponsored by the International Society for Advancement of Cytometry (ISAC) and the US National Institute of Standards and Technology (NIST) are reported. The study evaluated the variability of assigning intensity values to fluorophore standard beads by bead manufacturers and the variability of cross calibrating the standard beads to stained polymer beads (hard-dyed beads) using different flow cytometers. Hard dyed beads are generally not spectrally matched to the fluorophores used to stain cells, and spectral response varies among flow cytometers. Thus if hard dyed beads are used as fluorescence calibrators, one expects calibration for specific fluorophores (e.g., FITC or PE) to vary among different instruments. Using standard beads surface-stained with specific fluorophores (FITC, PE, APC, and Pacific Blue™), the study compared the measured intensity of fluorophore standard beads to that of hard dyed beads through cross calibration on 133 different flow cytometers. Using robust CV as a measure of variability, the variation of cross calibrated values was typically 20% or more for a particular hard dyed bead in a specific detection channel. The variation across different instrument models was often greater than the variation within a particular instrument model. As a separate part of the study, NIST and four bead manufacturers used a NIST supplied protocol and calibrated fluorophore solution standards to assign intensity values to the fluorophore beads. Values assigned to the reference beads by different groups varied by orders of magnitude in most cases, reflecting differences in instrumentation used to perform the calibration. The study concluded that the use of any spectrally unmatched hard dyed bead as a general fluorescence calibrator must be verified and characterized for every particular instrument model. Close interaction between bead manufacturers and NIST is recommended to have reliable and uniformly assigned

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device

PubMed Central

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-01-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO3) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO3 solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery. PMID:22685500

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device.

PubMed

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-09-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO(3)) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO(3) solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery.

Properties of alginate fiber spun-dyed with fluorescent pigment dispersion.

PubMed

Wang, Ping; Tawiah, Benjamin; Tian, Anli; Wang, Chunxia; Zhang, Liping; Fu, Shaohai

2015-03-15

Spun-dyed alginate fiber was prepared by the spun-dyeing method with the mixture of fluorescent pigment dispersion and sodium alginate fiber spinning solution, and its properties were characterized by SEM, TGA, DSC, and XRD. The results indicate that fluorescent pigment dispersion prepared with esterified poly (styrene-alt maleic acid) had excellent compatibility with sodium alginate fiber spinning solution, and small amount of fluorescent pigment could reduce the viscosity of spun-dyed spinning solutions. SEM photo of spun-dyed alginate fiber indicated that fewer pigment particles deposited on its surface. TGA, DSC, and XRD results suggested that thermal properties and crystal phase of spun-dyed alginate fibers had slight changes compared to the original alginate fibers. The fluorescence intensity of spun-dyed alginate fiber reached its maximum when the content of fluorescent pigment was 4%. The spun-dyed alginate fiber showed excellent rubbing and washing fastness. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis of a novel alginate-rubber joint immobilization strains H-1 and its application in removal of Pb (II) from aqueous solution

NASA Astrophysics Data System (ADS)

Li, Huidong; Huo, Kaili; Li, Xiaolei; Zhang, Lin; Yun, Yueqing; Song, Lei; Bai, Runying; Liu, Yuhong

2018-02-01

In this study, a novel alginate-rubber-strains immobilized beads (ARSIBs) was synthesized at the optimum conditions that the concentration of sodium alginate was 4%; the volume of bacterial suspension was 75%; the quality of rubber powder was 3.2%; the crosslinking time was 24 h by the orthogonal experiments. The optimum conditions for Pb (II) adsorption were 1.2% ARSIBs, 100 mg L-1 initial concentrations, pH 5 and 3 h contact time. The equilibrium data were well fitted by the Freundlich isotherm model. The biosorption process was nearly consistent with the pseudo-second-order model. Meanwhile, the biosorption mechanism could be that Pb (II) was adsorbed by the hydroxyl and carboxyl, finally precipitated with phosphate in the form of NaPb4(PO4)3, Pb5(PO4)3(OH) and Pb(H2PO4)2 based on the spectra of FTIR and XRD, respectively. In addition, the stability of ARSIBs was enhanced due to the addition to the rubber powder in the process of wastewater treatment.

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. Copyright © 2015. Published by Elsevier B.V.

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

PubMed

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

2013-06-01

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

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

The Potency of Local Bacterial Isolates Encapsulated Within Sodium Alginate in Carbofuran Degradation

NASA Astrophysics Data System (ADS)

Priyani, Nunuk; Pratiwi, Dian; Suryanto, Dwi

2018-03-01

Research on the viability of bacteria encapsulated within sodium alginate and their potential in carbofuran degradation has been done. A total of 8 bacterial isolates have been isolated from slaughter house waste. A 100 ml of Bushnell-Hass Broth (BHB) medium containing 146.982 ppm of carbofuran was used as a medium. As much as 2 gr of beads which equal to 108cells.ml‑1 was inoculated into each medium culture and incubated for 15 days at ambient temperature and was shaken at 100 rpm. Analysis of carbofuran residues using High Performance Liquid Chromatography (HPLC) showed that the best 2 isolates, DN 1 and OR 2, were able to decrease carbofuran phenol concentration up to 30.37 % and 32.09% respectively compared to control. These results suggested that no significant different from the ability of free cell which decreased carbofuran phenol concentration up to 32.54% and 28.29%.

Study of The Effect of Draw-bead Geometry on Stretch Flange Formability

NASA Astrophysics Data System (ADS)

Orlov, O. S.; Winkler, S. L.; Worswick, M. J.; Lloyd, D. J.; Finn, M. J.

2004-06-01

A fully instrumented stretch flange press equipped with a back-up punch and draw-beads near the specimen cutout area is simulated. The utilization of different draw-bead geometries is examined numerically to determine the restraining forces, strains and amount of damage generated in stretch flanges during forming. Simulations of the forming process are conducted for 1mm AA5182 sheets with circular cutouts. The damage evolution with the deformed specimens is investigated using the explicit dynamic finite element code, LS-DYNA, with a modified Gurson-based material model. It was found that double draw-beads can provide the same amount of restraining force as single draw-beads, but at reduced levels of damage.

Chloride Cotransporters as a Molecular Mechanism underlying Spreading Depolarization-Induced Dendritic Beading.

PubMed

Steffensen, Annette B; Sword, Jeremy; Croom, Deborah; Kirov, Sergei A; MacAulay, Nanna

2015-09-02

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. 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 space in association with

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

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.

Combined of ultrasound irradiation with high hydrostatic pressure (US/HHP) as a new method to improve immobilization of dextranase onto alginate gel.

PubMed

Bashari, Mohanad; Abbas, Shabbar; Xu, Xueming; Jin, Zhengyu

2014-07-01

In this research work, dextranase was immobilized onto calcium alginate beads by the combination of ultrasonic irradiation and high hydrostatic pressure (US/HHP) treatments. Effects of US/HHP treatments on loading efficiency and immobilization yield of dextranase enzyme onto calcium alginate beads were investigated. Furthermore, the activities of immobilized enzymes prepared with and without US/HHP treatments and that prepared with ultrasonic irradiation (US) and high hydrostatic pressure (HHP), as a function of pH, temperature, recyclability and enzyme kinetic parameters, were compared with that for free enzyme. The maximum loading efficiency and the immobilization yield were observed when the immobilized dextranase was prepared with US (40 W at 25 kHz for 15 min) combined with HHP (400 MPa for 15 min), under which the loading efficiency and the immobilization yield increased by 88.92% and 80.86%, respectively, compared to immobilized enzymes prepared without US/HHP treatment. On the other hand, immobilized enzyme prepared with US/HHP treatment showed Vmax, KM, catalytic and specificity constants values higher than that for the immobilized enzyme prepared with HHP treatment, indicated that, this new US/HHP method improved the catalytic kinetics activity of immobilized dextranase at all the reaction conditions studied. Compared to immobilized enzyme prepared either with US or HHP, the immobilized enzymes prepared with US/HHP method exhibited a higher: pH optimum, optimal reaction temperature, thermal stability and recyclability, and lower activation energy, which, illustrating the effectiveness of the US/HHP method. These results indicated that, the combination of US and HHP treatments could be an effective method for improving the immobilization of enzymes in polymers. Copyright © 2014 Elsevier B.V. All rights reserved.

Alginate-based hybrid aerogel microparticles for mucosal drug delivery.

PubMed

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

2016-10-01

The application of biopolymer aerogels as drug delivery systems (DDS) has gained increased interest during the last decade since these structures have large surface area and accessible pores allowing for high drug loadings. Being biocompatible, biodegradable and presenting low toxicity, polysaccharide-based aerogels are an attractive carrier to be applied in pharmaceutical industry. Moreover, some polysaccharides (e.g. alginate and chitosan) present mucoadhesive properties, an important feature for mucosal drug delivery. This feature allows to extend the contact of DDS with biological membranes, thereby increasing the absorption of drugs through the mucosa. Alginate-based hybrid aerogels in the form of microparticles (<50μm) were investigated in this work as carriers for mucosal administration of drugs. Low methoxyl pectin and κ-carrageenan were co-gelled with alginate and further dried with supercritical CO2 (sc-CO2). Spherical mesoporous aerogel microparticles were obtained for alginate, hybrid alginate/pectin and alginate/κ-carrageenan aerogels, presenting high specific surface area (370-548m(2)g(-1)) and mucoadhesive properties. The microparticles were loaded with ketoprofen via adsorption from its solution in sc-CO2, and with quercetin via supercritical anti-solvent precipitation. Loading of ketoprofen was in the range between 17 and 22wt% whereas quercetin demonstrated loadings of 3.1-5.4wt%. Both the drugs were present in amorphous state. Loading procedure allowed the preservation of antioxidant activity of quercetin. Release of both drugs from alginate/κ-carrageenan aerogel was slightly faster compared to alginate/pectin. The results indicate that alginate-based aerogel microparticles can be viewed as promising matrices for mucosal drug delivery applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of gamma-irradiation on degradation of alginate.

PubMed

Lee, Dong Wook; Choi, Won Seok; Byun, Myung Woo; Park, Hyun Jin; Yu, Yong-Man; Lee, Chong M

2003-07-30

The aqueous solution of alginate was irradiated by 60Co gamma-rays in the dose range of 10-500 kGy. To assess the effect of irradiation on the degradation of alginate, the irradiation-induced changes in the viscosity, molecular weight, color, monomer composition, and sequence were measured. The molecular weight of raw alginate was reduced from 300000 to 25000 when irradiated at 100 kGy. The degradation rate decreased and the chain breaks per molecule increased with increasing irradiation dose. The viscosity of irradiated alginate solution reached a near minimum as low as at 10 kGy. No appreciable color changes were observed in the samples irradiated at up to 100 kGy, but intense browning occurred beyond 200 kGy. The 13C NMR spectra showed that homopolymeric blocks, MM and GG, increased and the M/G ratio decreased with irradiation. Considering both the level of degradation and the color change of alginate, the optimum irradiation dose was found to be 100 kGy.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

3D culture of human pluripotent stem cells in RGD-alginate hydrogel improves retinal tissue development.

PubMed

Hunt, Nicola C; Hallam, Dean; Karimi, Ayesha; Mellough, Carla B; Chen, Jinju; Steel, David H W; Lako, Majlinda

2017-02-01

No treatments exist to effectively treat many retinal diseases. Retinal pigmented epithelium (RPE) and neural retina can be generated from human embryonic stem cells/induced pluripotent stem cells (hESCs/hiPSCs). The efficacy of current protocols is, however, limited. It was hypothesised that generation of laminated neural retina and/or RPE from hiPSCs/hESCs could be enhanced by three dimensional (3D) culture in hydrogels. hiPSC- and hESC-derived embryoid bodies (EBs) were encapsulated in 0.5% RGD-alginate; 1% RGD-alginate; hyaluronic acid (HA) or HA/gelatin hydrogels and maintained until day 45. Compared with controls (no gel), 0.5% RGD-alginate increased: the percentage of EBs with pigmented RPE foci; the percentage EBs with optic vesicles (OVs) and pigmented RPE simultaneously; the area covered by RPE; frequency of RPE cells (CRALBP+); expression of RPE markers (TYR and RPE65) and the retinal ganglion cell marker, MATH5. Furthermore, 0.5% RGD-alginate hydrogel encapsulation did not adversely affect the expression of other neural retina markers (PROX1, CRX, RCVRN, AP2α or VSX2) as determined by qRT-PCR, or the percentage of VSX2 positive cells as determined by flow cytometry. 1% RGD-alginate increased the percentage of EBs with OVs and/or RPE, but did not significantly influence any other measures of retinal differentiation. HA-based hydrogels had no significant effect on retinal tissue development. The results indicated that derivation of retinal tissue from hESCs/hiPSCs can be enhanced by culture in 0.5% RGD-alginate hydrogel. This RGD-alginate scaffold may be useful for derivation, transport and transplantation of neural retina and RPE, and may also enhance formation of other pigmented, neural or epithelial tissue. The burden of retinal disease is ever growing with the increasing age of the world-wide population. Transplantation of retinal tissue derived from human pluripotent stem cells (PSCs) is considered a promising treatment. However, derivation of

Ag/alginate nanofiber membrane for flexible electronic skin

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

Injectable MMP-sensitive alginate hydrogels as hMSC delivery systems.

PubMed

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

2014-01-13

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

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

PubMed

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

2015-12-21

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

Boron removal by a composite sorbent: Polyethylenimine/tannic acid derivative immobilized in alginate hydrogel beads.

PubMed

Bertagnolli, Caroline; Grishin, Andrey; Vincent, Thierry; Guibal, Eric

2017-03-21

A novel composite material was prepared by the grafting of tannic acid on polyethylenimine (PEI), which allows an efficient sorption of boron (sorption capacity close to 0.89 mmol B g -1 ). The encapsulation of this chelating sorbent (finely crushed) facilitates its use (readily solid/liquid separation, use in fixed-bed columns) at the expense of a loss in sorption capacity (proportionally decreased by the introduction of alginate having poor efficiency for boron uptake). Sorption isotherms are modeled using the Langmuir equation, while the kinetic profiles are presented a good fit by pseudo-second order rate equation. In addition, the encapsulating matrix introduces supplementary resistance to intraparticle diffusion, especially when the resin is dried without control: freeze-drying partially limits this effect. The stability (at long-term storage) of the sorbent is improved when the sorbent is stored under nitrogen atmosphere. The presence of an excess of NaCl was investigated. The degradation of the hydrogel (by ion-exchange of Ca(II) with Na(I)) leads to a decrease in the sorption performance of composite material but the action of Ca(II) ions in the solutions re-stabilizes the hydrogel.

Encapsulation of cell into monodispersed hydrogels on microfluidic device

NASA Astrophysics Data System (ADS)

Choi, Chang-Hyoung; Lee, Ji-Hye; Shim, Hyun-Woo; Lee, Nae-Rym; Jung, Jae-Hoon; Yoon, Tae-Ho; Kim, Dong-Pyo; Lee, Chang-Soo

2007-12-01

In here, we present the microfluidic approach to produce monodispersed microbeads that will contain viable cells. The utilization of microfludics is helpful to synthesize monodispersed alginate hydrogels and in situ encapsulate cell into the generating hydrogels in microfludic device. First, the condition of formation of hydrogels in multiphase flows including oil, CaCl II, and alginate was optimized. Based on the preliminary survey, microfludic device could easily manipulate the size of alginate beads having narrow size distribution. The microfluidic method manipulates the size of hydrogel microbeads from 30 to 200um with a variation less than 2%. For the proof of concept of cell entrapment, the live yeast expressing green fluorescence protein is successfully encapsulated in microfluidic device.

Three-dimensional plotting of a cell-laden alginate/methylcellulose blend: towards biofabrication of tissue engineering constructs with clinically relevant dimensions.

PubMed

Schütz, Kathleen; Placht, Anna-Maria; Paul, Birgit; Brüggemeier, Sophie; Gelinsky, Michael; Lode, Anja

2017-05-01

Biofabrication of tissue engineering constructs with tailored architecture and organized cell placement using rapid prototyping technologies is a major research focus in the field of regenerative therapies. This study describes a novel alginate-based material suitable for both cell embedding and fabrication of three-dimensional (3D) structures with predefined geometry by 3D plotting. The favourable printing properties of the material were achieved by using a simple strategy: addition of methylcellulose (MC) to a 3% alginate solution resulted in a strongly enhanced viscosity, which enabled accurate and easy deposition without high technical efforts. After scaffold plotting, the alginate chains were crosslinked with Ca 2+ ; MC did not contribute to the gelation and was released from the scaffolds during the following cultivation. The resulting constructs are characterized by high elasticity and stability, as well as an enhanced microporosity caused by the transient presence of MC. The suitability of the alginate/MC blend for cell embedding was evaluated by direct incorporation of mesenchymal stem cells during scaffold fabrication. The embedded cells showed high viability after 3 weeks of cultivation, which was similar to those of cells within pure alginate scaffolds which served as control. Maintenance of the differentiation potential of embedded cells, as an important requirement for the generation of functional tissue engineering constructs, was proven for adipogenic differentiation as a model for soft tissue formation. In conclusion, the temporary integration of MC into a low-concentrated alginate solution allowed the generation of scaffolds with dimensions in the range of centimetres without loss of the positive properties of low-concentrated alginate hydrogels with regard to cell embedding. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Deterministic bead-in-droplet ejection utilizing an integrated plug-in bead dispenser for single bead–based applications

PubMed Central

Kim, Hojin; Choi, In Ho; Lee, Sanghyun; Won, Dong-Joon; Oh, Yong Suk; Kwon, Donghoon; Sung, Hyung Jin; Jeon, Sangmin; Kim, Joonwon

2017-01-01

This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead–encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin–biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules. PMID:28393911

The Sequencing Bead Array (SBA), a Next-Generation Digital Suspension Array

PubMed Central

Akhras, Michael S.; Pettersson, Erik; Diamond, Lisa; Unemo, Magnus; Okamoto, Jennifer; Davis, Ronald W.; Pourmand, Nader

2013-01-01

Here we describe the novel Sequencing Bead Array (SBA), a complete assay for molecular diagnostics and typing applications. SBA is a digital suspension array using Next-Generation Sequencing (NGS), to replace conventional optical readout platforms. The technology allows for reducing the number of instruments required in a laboratory setting, where the same NGS instrument could be employed from whole-genome and targeted sequencing to SBA broad-range biomarker detection and genotyping. As proof-of-concept, a model assay was designed that could distinguish ten Human Papillomavirus (HPV) genotypes associated with cervical cancer progression. SBA was used to genotype 20 cervical tumor samples and, when compared with amplicon pyrosequencing, was able to detect two additional co-infections due to increased sensitivity. We also introduce in-house software Sphix, enabling easy accessibility and interpretation of results. The technology offers a multi-parallel, rapid, robust, and scalable system that is readily adaptable for a multitude of microarray diagnostic and typing applications, e.g. genetic signatures, single nucleotide polymorphisms (SNPs), structural variations, and immunoassays. SBA has the potential to dramatically change the way we perform probe-based applications, and allow for a smooth transition towards the technology offered by genomic sequencing. PMID:24116138

Confocal nanoscanning, bead picking (CONA): PickoScreen microscopes for automated and quantitative screening of one-bead one-compound libraries.

PubMed

Hintersteiner, Martin; Buehler, Christof; Uhl, Volker; Schmied, Mario; Müller, Jürgen; Kottig, Karsten; Auer, Manfred

2009-01-01

Solid phase combinatorial chemistry provides fast and cost-effective access to large bead based libraries with compound numbers easily exceeding tens of thousands of compounds. Incubating one-bead one-compound library beads with fluorescently labeled target proteins and identifying and isolating the beads which contain a bound target protein, potentially represents one of the most powerful generic primary high throughput screening formats. On-bead screening (OBS) based on this detection principle can be carried out with limited automation. Often hit bead detection, i.e. recognizing beads with a fluorescently labeled protein bound to the compound on the bead, relies on eye-inspection under a wide-field microscope. Using low resolution detection techniques, the identification of hit beads and their ranking is limited by a low fluorescence signal intensity and varying levels of the library beads' autofluorescence. To exploit the full potential of an OBS process, reliable methods for both automated quantitative detection of hit beads and their subsequent isolation are needed. In a joint collaborative effort with Evotec Technologies (now Perkin-Elmer Cellular Technologies Germany GmbH), we have built two confocal bead scanner and picker platforms PS02 and a high-speed variant PS04 dedicated to automated high resolution OBS. The PS0X instruments combine fully automated confocal large area scanning of a bead monolayer at the bottom of standard MTP plates with semiautomated isolation of individual hit beads via hydraulic-driven picker capillaries. The quantification of fluorescence intensities with high spatial resolution in the equatorial plane of each bead allows for a reliable discrimination between entirely bright autofluorescent beads and real hit beads which exhibit an increased fluorescence signal at the outer few micrometers of the bead. The achieved screening speed of up to 200,000 bead assayed in less than 7 h and the picking time of approximately 1 bead

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

PubMed Central

Mantilaka, M. M. M. G. P. G.; Goh, K. L.; Ratnayake, S. P.; Amaratunga, G. A. J.; de Silva, K. M. Nalin

2017-01-01

Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol) (PVA) polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm) at a predetermined concentration (10% (w/w)), is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P < 0.05). In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues. PMID:28694826

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.

A comparative study with biologically and chemically synthesized nZVI: applications in Cr (VI) removal and ecotoxicity assessment using indigenous microorganisms from chromium-contaminated site.

PubMed

Ravikumar, K V G; Kumar, Deepak; Rajeshwari, A; Madhu, G M; Mrudula, P; Chandrasekaran, Natarajan; Mukherjee, Amitava

2016-02-01

In the present communication, we report a comparative study of Cr (VI) removal using biologically synthesized nano zero valent iron (BS-nZVI) and chemically synthesized nZVI (CS-nZVI), both immobilized in calcium alginate beads. The parameters like initial Cr (VI) concentration, nZVI concentration, and the contact time for Cr (VI) removal were optimized based on Box-Behnken design (BBD) by response surface modeling at a constant pH 7. Under the optimized conditions (concentration of nZVI = 1000 mg L(-1), contact time = ∼ 80 min, and initial concentration of Cr (VI) = 10 mg L(-1)), the Cr (VI) removal by the immobilized BS-nZVI and CS-nZVI alginate beads was 80.04 and 81.08 %, respectively. The adsorption of Cr (VI) onto the surface of alginate beads was confirmed by scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. The applicability of the process using both the sorbents was successfully test medium Cr (VI) spiked environmental water samples. In order to assess the ecotoxic effects of nZVI, the decline in cell viability, generation of intracellular reactive oxygen species (ROS), cell membrane damage, and biouptake was studied at 1000 mg L(-1) concentration, with five indigenous bacterial isolates from chromium-contaminated lake sediments and their consortium.

Outcomes of Newer Generation Cementless Total Knee Arthroplasty: Beaded Periapatite-Coated vs Highly Porous Titanium-Coated Implants.

PubMed

Harwin, Steven F; Patel, Nirav K; Chughtai, Morad; Khlopas, Anton; Ramkumar, Prem N; Roche, Martin; Mont, Michael A

2017-07-01

Newer generation cementless total knee arthroplasty (TKA) designs are available and have novel implant coatings. We evaluated and compared beaded periapatite (PA)-coated vs highly porous titanium-coated cementless TKAs. Specifically, we compared: (1) survivorship, (2) Knee Society Scores (KSSs) and range of motion, (3) complications, and (4) radiographic findings. There were 805 TKAs with beaded PA-coated tibial and patellar components (PA group; mean age 67 years; range 41-86 years), and 219 TKAs with highly porous titanium-coated tibial and patella components (mean age 66 years; range 34-88 years). Mean follow-up was 4.4 years (range 2-9 years; median 4 years). Implant survivorship was calculated using Kaplan-Meier curves. Student t-tests and chi-square tests were used as appropriate. Radiographic evaluation was performed using Knee Society Roentgenographic Evaluation and Scoring System. All-cause implant survivorship in beaded PA-coated group was 99.5% (95% CI, 97.9%-99.9%) and 99.5% (95% CI, 92.7%-99.9%) in highly porous titanium-coated group. There were no significant differences in the KSS for pain and function. Improvement in flexion and extension was similar in the 2 groups. Overall, complication rate (2.2% vs 2.3%; P = .274) and number of revisions (6 [0.8%] vs 2 [0.2%]; P = .936) were similar in the 2 groups. Excluding the aseptic and septic failures, there were no progressive radiolucencies or osteolysis on radiographic evaluation. This study has shown good clinical and patient-reported outcomes of cementless TKA for both implants. Future multicenter large scale clinical and cost-effectiveness studies are needed to determine the superiority of one cementless implant type over the other. Copyright © 2017 Elsevier Inc. All rights reserved.

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

2016-03-22

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.

Preparation and release characteristics of polymer-coated and blended alginate microspheres.

PubMed

Lee, D W; Hwang, S J; Park, J B; Park, H J

2003-01-01

To prevent a rapid drug release from alginate microspheres in simulated intestinal media, alginate microspheres were coated or blended with polymers. Three polymers were selected and evaluated such as HPMC, Eudragit RS 30D and chitosan, as both coating materials and additive polymers for controlling the drug release. This study focused on the release characteristics of polymer-coated and blended alginate microspheres, varying the type of polymer and its concentration. The alginate microspheres were prepared by dropping the mixture of drug and sodium alginate into CaCl(2) solution using a spray-gun. Polymer-coated microspheres were prepared by adding alginate microspheres into polymer solution with mild stirring. Polymer-blended microspheres were prepared by dropping the mixture of drug, sodium alginate and additive polymer with plasticizer into CaCl(2) solution. In vitro release test was carried out to investigate the release profiles in 500 ml of phosphate buffered saline (PBS, pH 7.4). As the amount of polymer in sodium alginate or coating solution increase, the drug release generally decreased. HPMC-blended microspheres swelled but withstood the disintegration, showing an ideal linear release profiles. Chitosan-coated microspheres showed smooth and round surface and extended the release of drug. In comparison with chitosan-coated microspheres, HPMC-blended alginate microspheres can be easily made and used for controlled drug delivery systems due to convenient process and controlled drug release.

Layer-by-Layer Alginate and Fungal Chitosan Based Edible Coatings Applied to Fruit Bars.

PubMed

Bilbao-Sainz, Cristina; Chiou, Bor-Sen; Punotai, Kaylin; Olson, Donald; Williams, Tina; Wood, Delilah; Rodov, Victor; Poverenov, Elena; McHugh, Tara

2018-05-30

Food waste is currently being generated at an increasing rate. One proposed solution would be to convert it to biopolymers for industrial applications. We recovered chitin from mushroom waste and converted it to chitosan to produce edible coatings. We then used layer-by-layer (LbL) electrostatic deposition of the polycation chitosan and the polyanion alginate to coat fruit bars enriched with ascorbic acid. The performance of the LbL coatings was compared with those containing single layers of fungal chitosan, animal origin chitosan and alginate. Bars containing alginate-chitosan LbL coatings showed increased ascorbic acid content, antioxidant capacity, firmness and fungal growth prevention during storage. Also, the origin of the chitosan did not affect the properties of the coatings. Mushroom stalk bases could be an alternative source for isolating chitosan with similar properties to animal-based chitosan. Also, layer-by-layer assembly is a cheap, simple method that can improve the quality and safety of fruit bars. © 2018 Institute of Food Technologists®.

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 “propylene...

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 “propylene...

Applications of Alginate-Based Bioinks in 3D Bioprinting.

PubMed

Axpe, Eneko; Oyen, Michelle L

2016-11-25

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

Applications of Alginate-Based Bioinks in 3D Bioprinting

PubMed Central

Axpe, Eneko; Oyen, Michelle L.

2016-01-01

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

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

Seeds used for Bodhi beads in China.

PubMed

Li, Feifei; Li, Jianqin; Liu, Bo; Zhuo, Jingxian; Long, Chunlin

2014-01-30

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. 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. 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. 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.

Guluronic acid content as a factor affecting turbidity removal potential of alginate.

PubMed

Kıvılcımdan Moral, Çiğdem; Ertesvåg, Helga; Sanin, F Dilek

2016-11-01

Alginates are natural polymers composed of mannuronic and guluronic acid residues. They are currently extracted from brown algae; however, alginate can also be synthesized by some species of Azotobacter and Pseudomonas. Alginates with different proportion of mannuronic and guluronic acids are known to have different characteristics and form gels at different extents in the presence of calcium ions. The aim of this work was to investigate the usefulness of alginate as a non-toxic coagulant used in purification of drinking water. This study utilized alginates from Azotobacter vinelandii having different guluronic acid levels. These were obtained partly by changing the cultivation parameters, partly by epimerizing a purified alginate sample in vitro using the A. vinelandii mannuronan C-5 epimerase AlgE1. The different alginates were then used for coagulation together with calcium. The results showed that turbidity removal capability was dependent on the content of guluronic acid residues. For the best performing samples, the turbidity decreased from 10 NTU to 1 NTU by the use of only 2 mg/L of alginate and 1.5 mM of calcium chloride.

Electrochemically controlled drug-mimicking protein release from iron-alginate thin-films associated with an electrode.

PubMed

Jin, Zhiyuan; Güven, Güray; Bocharova, Vera; Halámek, Jan; Tokarev, Ihor; Minko, Sergiy; Melman, Artem; Mandler, Daniel; Katz, Evgeny

2012-01-01

Novel biocompatible hybrid-material composed of iron-ion-cross-linked alginate with embedded protein molecules has been designed for the signal-triggered drug release. Electrochemically controlled oxidation of Fe(2+) ions in the presence of soluble natural alginate polymer and drug-mimicking protein (bovine serum albumin, BSA) results in the formation of an alginate-based thin-film cross-linked by Fe(3+) ions at the electrode interface with the entrapped protein. The electrochemically generated composite thin-film was characterized by electrochemistry and atomic force microscopy (AFM). Preliminary experiments demonstrated that the electrochemically controlled deposition of the protein-containing thin-film can be performed at microscale using scanning electrochemical microscopy (SECM) as the deposition tool producing polymer-patterned spots potentially containing various entrapped drugs. Application of reductive potentials on the modified electrode produced Fe(2+) cations which do not keep complexation with alginate, thus resulting in the electrochemically triggered thin-film dissolution and the protein release. Different experimental parameters, such as the film-deposition time, concentrations of compounds and applied potentials, were varied in order to demonstrate that the electrodepositon and electrodissolution of the alginate composite film can be tuned to the optimum performance. A statistical modeling technique was applied to find optimal conditions for the formation of the composite thin-film for the maximal encapsulation and release of the drug-mimicking protein at the lowest possible potential. © 2011 American Chemical Society

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

NASA Astrophysics Data System (ADS)

Choudhary, Soumitra

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

Role of alginate in antibacterial finishing of textiles.

PubMed

Li, Jiwei; He, Jinmei; Huang, Yudong

2017-01-01

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

In vitro evaluation of antibiotic diffusion from antibiotic-impregnated biodegradable beads and polymethylmethacrylate beads.

PubMed Central

Mader, J T; Calhoun, J; Cobos, J

1997-01-01

Antibiotic-impregnated beads are used in the dead bone space following debridement surgery to deliver local, high concentrations of antibiotics. Polymethylmethacrylate (PMMA), 2,000-molecular-weight (MW) polylactic acid (PLA), Poly(DL-lactide)-coglycolide (PL:CG; 90:10, 80:20, and 70:30), and the combination 2,000-MW PLA-70:20 PL:CG were individually mixed with clindamycin, tobramycin, or vancomycin. Beads were placed in 1 ml of phosphate-buffered saline (PBS) and incubated at 37 degrees C. The PBS was changed daily, and the removed PBS samples were stored at -70 degrees C until the antibiotic in each sample was determined by microbiological disk diffusion assay. Nondissolving PMMA beads with tobramycin and clindamycin had concentrations well above breakpoint sensitivity concentrations (i.e., the antibiotic concentrations at the transition point between bacterial killing and resistance to the antibiotic) for more than 90 days, but vancomycin concentrations dropped by day 12. ALl PLA, PL:CG, and the 2,000-MW PLA-70:30 PL:CG biodegradable beads release high concentrations of all the antibiotics in vitro for the period of time needed to treat bone infections (i.e., 4 to 8 weeks). Antibiotic-loaded PLA and PL:CG beads have the advantage of better antibiotic elution and the ability to biodegradable (thereby averting the need for secondary surgery for bead removal) compared to the PMMA beads presently used in the clinical setting. PMID:9021200

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.

3-Chloro-1,2-propanediol biodegradation by Ca-alginate immobilized Pseudomonas putida DSM 437 cells applying different processes: mass transfer effects.

PubMed

Konti, Aikaterini; Mamma, Diomi; Hatzinikolaou, Dimitios G; Kekos, Dimitris

2016-10-01

3-Chloro-1,2-propanediol (3-CPD) biodegradation by Ca-alginate immobilized Pseudomonas putida cells was performed in batch system, continuous stirred tank reactor (CSTR), and packed-bed reactor (PBR). Batch system exhibited higher biodegradation rates and 3-CPD uptakes compared to CSTR and PBR. The two continuous systems (CSTR and PBR) when compared at 200 mg/L 3-CPD in the inlet exhibited the same removal of 3-CPD at steady state. External mass-transfer limitations are found negligible at all systems examined, since the observable modulus for external mass transfer Ω ≪ 1 and the Biot number Bi > 1. Intra-particle diffusion resistance had a significant effect on 3-CPD biodegradation in all systems studied, but to a different extent. Thiele modulus was in the range of 2.5 in batch system, but it was increased at 11 when increasing cell loading in the beads, thus lowering significantly the respective effectiveness factor. Comparing the systems at the same cell loading in the beads PBR was less affected by internal diffusional limitations compared to CSTR and batch system, and, as a result, exhibited the highest overall effectiveness factor.

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.

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.

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.

Small, porous polyacrylate beads

NASA Technical Reports Server (NTRS)

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

Coating Layer Characterization of Laser Deposited AlSi Coating over Laser Weld Bead

NASA Astrophysics Data System (ADS)

Gu, Hongping; Van Gelder, Aldo

Corrosion protection of steel components is an important topic in automotive industry. Laser beam welding makes a narrow weld bead, thus minimizing the damage to the original coating on the steel material. However, the weld bead loses its original coating and is vulnerable to corrosive attack. It was demonstrated in this study that laser beam generated AlSi coating is an effective way to apply a protective coating on the weld bead. Coatings with different thickness and topography have been deposited under different laser power and processing speed. The microstructure of the as-deposited coating and its evolution after heat treatment has been studied. EDS was employed to analyze the distribution of chemical compositions of the laser generated coatings. Several metallic compounds of Al and iron have been identified. It was found that the type of metallic compounds can be influenced by the laser processing parameters.

Droplet-based microfluidic system for multicellular tumor spheroid formation and anticancer drug testing.

PubMed

Yu, Linfen; Chen, Michael C W; Cheung, Karen C

2010-09-21

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since it may provide a better model than monolayer culture of tumor cells. Moreover, continuous dynamic perfusion allows the establishment of long term cell culture and subsequent multicellular spheroid formation. A droplet-based microfluidic system was used to form alginate beads with entrapped breast tumor cells. After gelation, the alginate beads were trapped in microsieve structures for cell culture in a continuous perfusion system. The alginate environment permitted cell proliferation and the formation of multicellular spheroids was observed. The dose-dependent response of the tumor spheroids to doxorubicin, and anticancer drug, showed multicellular resistance compared to conventional monolayer culture. The microsieve structures maintain constant location of each bead in the same position throughout the device seeding process, cell proliferation and spheroid formation, treatment with drug, and imaging, permitting temporal and spatial tracking.

Alginate microparticles as oral colon drug delivery device: A review.

PubMed

Agüero, Lissette; Zaldivar-Silva, Dionisio; Peña, Luis; Dias, Marcos L

2017-07-15

The increase in the research interest on alginate microparticles in pharmaceutical and biomedical areas confirms its potential use as an effective matrix for drug and cell delivery. Among the well known alginate properties, pH sensitivity remains as an attractive option for targeting of drug in the colon region. This essential aspect is advantageous to enhance therapeutic efficacy of treatment of inflammatory bowel diseases, which require multi-drug administration frequently in a long period. As consequence, severe side effect appears leading to discontinuation of therapy and affecting quality of patient life. This review gives an overview of relevant properties of alginate as oral colon delivery systems and the recent innovative strategies of using alginate with other polymers as well as microencapsulation techniques. At the same time, it describes the several advantages of coating processes involving alginate over microparticles in order to design better material with sustained release characteristic for colon-targeted delivery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

PubMed Central

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

2016-01-01

Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined. The results showed that the tensile modulus value of the nanocomposite films increased from 308 to 1403 MPa with increasing CNF content from 0% to 10%; however, it decreased with further increase of the filler content. Incorporation of CNF also significantly reduced the swelling percentage and water solubility of alginate-based films, with the lower values found for 10 wt % in CNF. Biodegradation studies of the films in soil confirmed that the biodegradation time of alginate/CNF films greatly depends on the CNF content. The results evidence that the stronger intermolecular interaction and molecular compatibility between alginate and CNF components was at 10 wt % in CNF alginate films. PMID:28787850

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

PubMed

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

2017-12-01

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

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

PubMed

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

2016-01-01

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

Alginate Polymerization and Modification Are Linked in Pseudomonas aeruginosa

PubMed Central

Moradali, M. Fata; 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

A bead-spring chain as a one-dimensional polyelectrolyte gel.

PubMed

Manning, Gerald S

2018-05-23

The physical principles underlying expansion of a single-chain polyelectrolyte coil caused by Coulomb repulsions among its ionized groups, and the expansion of a cross-linked polyelectrolyte gel, are probably the same. In this paper, we analyze a "one-dimensional" version of a gel, namely, a linear chain of charged beads connected by Hooke's law springs. In the Debye-Hückel range of relatively weak Coulomb strength, where counterion condensation does not occur, the springs are realistically stretched on a nanolength scale by the repulsive interactions among the beads, if we use a spring constant normalized by the inverse square of the solvent Bjerrum length. The persistence length and radius of gyration counter-intuitively decrease when Coulomb strength is increased, if analyzed in the framework of an OSF-type theory; however, a buckling theory generates the increase that is consistent with bead-spring simulations.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2011-05-15

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

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

PubMed

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

2017-06-01

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

Empirical study of alginate impression materials by customized proportioning system

PubMed Central

2016-01-01

PURPOSE Alginate mixers available in the market do not have the automatic proportioning unit. In this study, an automatic proportioning unit for the alginate mixer and controller software were designed and produced for a new automatic proportioning unit. With this device, it was ensured that proportioning operation could arrange weight-based alginate impression materials. MATERIALS AND METHODS The variation of coefficient in the tested groups was compared with the manual proportioning. Compression tension and tear tests were conducted to determine the mechanical properties of alginate impression materials. The experimental data were statistically analyzed using one way ANOVA and Tukey test at the 0.05 level of significance. RESULTS No statistically significant differences in modulus of elastisity (P>0.3), tensional/compresional strength (P>0.3), resilience (P>0.2), strain in failure (P>0.4), and tear energy (P>0.7) of alginate impression materials were seen. However, a decrease in the standard deviation of tested groups was observed when the customized machine was used. To verify the efficiency of the system, powder and powder/water mixing were weighed and significant decrease was observed. CONCLUSION It was possible to obtain more mechanically stable alginate impression materials by using the custom-made proportioning unit. PMID:27826387

Engineering of In Vitro 3D Capillary Beds by Self-Directed Angiogenic Sprouting

PubMed Central

Chan, Juliana M.; Zervantonakis, Ioannis K.; Rimchala, Tharathorn; Polacheck, William J.; Whisler, Jordan; Kamm, Roger D.

2012-01-01

In recent years, microfluidic systems have been used to study fundamental aspects of angiogenesis through the patterning of single-layered, linear or geometric vascular channels. In vivo, however, capillaries exist in complex, three-dimensional (3D) networks, and angiogenic sprouting occurs with a degree of unpredictability in all x,y,z planes. The ability to generate capillary beds in vitro that can support thick, biological tissues remains a key challenge to the regeneration of vital organs. Here, we report the engineering of 3D capillary beds in an in vitro microfluidic platform that is comprised of a biocompatible collagen I gel supported by a mechanical framework of alginate beads. The engineered vessels have patent lumens, form robust ∼1.5 mm capillary networks across the devices, and support the perfusion of 1 µm fluorescent beads through them. In addition, the alginate beads offer a modular method to encapsulate and co-culture cells that either promote angiogenesis or require perfusion for cell viability in engineered tissue constructs. This laboratory-constructed vascular supply may be clinically significant for the engineering of capillary beds and higher order biological tissues in a scalable and modular manner. PMID:23226527

Microfluidic magnetic bead conveyor belt.

PubMed

van Pelt, Stijn; Frijns, Arjan; den Toonder, Jaap

2017-11-07

Magnetic beads play an important role in the miniaturization of clinical diagnostics systems. In lab-on-chip platforms, beads can be made to link to a target species and can then be used for the manipulation and detection of this species. Current bead actuation systems utilize complex on-chip coil systems that offer low field strengths and little versatility. We demonstrate a novel system based on an external rotating magnetic field and on-chip soft-magnetic structures to focus the field locally. These structures were designed and optimized using finite element simulations in order to create a number of local flux density maxima. These maxima, to which the magnetic beads are attracted, move over the chip surface in a continuous way together with the rotation of the external field, resulting in a mechanism similar to that of a conveyor belt. A prototype was fabricated using PDMS molding techniques mixed with iron powder for the magnetic structures. In the subsequent experiments, a quadrupole electromagnet was used to create the rotating external field. We observed that beads formed agglomerates that rolled over the chip surface, just above the magnetic structures. Field rotation frequencies between 0.1-50 Hz were tested resulting in magnetic bead speeds of over 1 mm s -1 for the highest frequency. With this, we have shown that our novel concept works, combining a simple design and simple operation with a powerful and versatile method for bead actuation. This makes it a promising method for further research and utilization in lab-on-chip systems.

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

PubMed

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

2017-05-01

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

Alginate/polymethacrylate copolymer microparticles for the intestinal delivery of enzymes.

PubMed

Scocca, Sarah; Faustini, Massimo; Villani, Simona; Munari, Eleonora; Conte, Ubaldo; Russo, Vincenzo; Riccardi, Alessia; Vigo, Daniele; Torre, Maria Luisa

2007-04-01

Proteins administered orally must pass through the gastric environment in order to reach their site of absorption in the intestine. How to protect these exogenously administered proteins from the damaging effects of gastric acid and pepsin proteolytic activity, which often induce irreversible structural and functional alterations to the molecules, is an intriguing challenge. Another problem is the physical and chemical instability of proteins during some technological processes, which often involve the use of organic solvents or high temperatures. In this study we investigated the use of alginate microparticles containing one of two enzymes, an enteric polymer and a lyoprotectant for the intestinal delivery of proteins. The two enzymes tested in this protein delivery system were lactate dehydrogenase and alpha-amylase: the former was chosen because of its sensitivity to denaturation, the latter for its relevance in nutrition and medicine. A sodium alginate aqueous solution containing the enteric polymer, a lyoprotectant and the enzyme was either extruded or sprayed into a calcium chloride solution, with the resultant formation of beads and microspheres which were freeze-dried. About 90% of the enzyme activity was maintained during the process of loading the proteins into the microparticles and the subsequent freeze-drying process. The stability of the encapsulated enzyme in an acid medium and the enzymatic activity in an intestinal environment were then investigated by a dissolution test. This consisted of exposing the microparticles to simulated gastric fluid (pH 1.2) for 2 hours and to simulated intestinal fluid (pH 7.5+/-0.1) for 1 hour. The morphology of the microparticles did not change in the acid environment, whereas they completely dissolved within 3 min in the simulated intestinal fluid. Residual enzymatic activity after the test remained satisfactory for both enzymes. In conclusion, these microparticle systems offer promise for applications in human and

Bead mediated separation of microparticles in droplets.

PubMed

Wang, Sida; Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead's solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield.

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

PubMed

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

2012-01-01

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

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

PubMed Central

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

2015-01-01

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

Evaluation of setting time and flow properties of self-synthesize alginate impressions

NASA Astrophysics Data System (ADS)

Halim, Calista; Cahyanto, Arief; Sriwidodo, Harsatiningsih, Zulia

2018-02-01

Alginate is an elastic hydrocolloid dental impression materials to obtain negative reproduction of oral mucosa such as to record soft-tissue and occlusal relationships. The aim of the present study was to synthesize alginate and to determine the setting time and flow properties. There were five groups of alginate consisted of fifty samples self-synthesize alginate and commercial alginate impression product. Fifty samples were divided according to two tests, each twenty-five samples for setting time and flow test. Setting time test was recorded in the s unit, meanwhile, flow test was recorded in the mm2 unit. The fastest setting time result was in the group three (148.8 s) and the latest was group fours). The highest flow test result was in the group three (69.70 mm2) and the lowest was group one (58.34 mm2). Results were analyzed statistically by one way ANOVA (α= 0.05), showed that there was a statistical significance of setting time while no statistical significance of flow properties between self-synthesize alginate and alginate impression product. In conclusion, the alginate impression was successfully self-synthesized and variation composition gives influence toward setting time and flow properties. The most resemble setting time of control group is group three. The most resemble flow of control group is group four.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

On-Chip generation of polymer microcapsules through droplet coalescence

NASA Astrophysics Data System (ADS)

Eqbal, Md Danish; Gundabala, Venkat; Gundabala lab Team

Alginate microbeads and microcapsules have numerous applications in drug delivery, tissue engineering and other biomedical areas due to their unique properties. Microcapsules with liquid core are of particular interest in the area of cell encapsulation. Various methods such as coacervation, emulsification, micro-nozzle, etc. exist for the generation of microbeads and microcapsules. However, these methods have several drawbacks like coagulation, non-uniformity, and polydispersity. In this work we present a method for complete on chip generation of alginate microcapsules (single core as well as double core) through the use of droplet merging technique. For this purpose, a combined Coflow and T-junction configuration is implemented in a hybrid glass-PDMS (Polydimethylsiloxane) microfluidic device. Efficient generation is achieved through precise matching of the generation rates of the coalescing drops. Through this approach, microcapsules with intact single and double (liquid) cores surrounded by alginate shell have been successfully generated and characterized.

In vivo evaluation of EPO-secreting cells immobilized in different alginate-PLL microcapsules.

PubMed

Ponce, S; Orive, G; Hernández, R M; Gascón, A R; Canals, J M; Muñoz, M T; Pedraz, J L

2006-11-01

Alginates are the most employed biomaterials for cell encapsulation due to their abundance, easy gelling properties and apparent biocompatibility. However, as natural polymers different impurities including endotoxins, proteins and polyphenols can be found in their composition. Several purification protocols as well as different batteries of assays to prove the biocompatibility of the alginates in vitro have been recently developed. However, little is known about how the use of alginates with different purity grade may affect the host immune response after their implantation in vivo. The present paper investigates the long-term functionality and biocompatibility of murine erythropoietin (EPO) secreting C2C12 cells entrapped in microcapsules elaborated with alginates with different properties (purity, composition and viscosity). Results showed that independently of the alginate type employed, the animals presented elevated hematocrit levels until day 130, remaining at values between 70-87%. However, histological analysis of the explanted devices showed higher overgrowth around non-biomedical grade alginate microcapsules which could be directly related with higher impurity content of this type of alginate. Although EPO delivery may be limited by the formation of a fibrotic layer around non-biomedical grade alginate microcapsules, the high EPO secretion of the encapsulated cells together with the pharmacodynamic behaviour and the angiogenic and immune-modulatory properties of EPO result in no direct correlation between the biocompatibility of the alginate and the therapeutic response obtained.

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

PubMed

Amir Afshar, Hamideh; Ghaee, Azadeh

2016-10-20

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

Jeffamine derivatized TentaGel beads and poly(dimethylsiloxane) microbead cassettes for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound combinatorial small molecule libraries.

PubMed

Townsend, Jared B; Shaheen, Farzana; Liu, Ruiwu; Lam, Kit S

2010-09-13

A method to efficiently immobilize and partition large quantities of microbeads in an array format in microfabricated poly(dimethylsiloxane) (PDMS) cassette for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound (OBOC) combinatorial libraries is described. Commercially available Jeffamine triamine T-403 (∼440 Da) was derivatized such that two of its amino groups were protected by Fmoc and the remaining amino group capped with succinic anhydride to generate a carboxyl group. This resulting trifunctional hydrophilic polymer was then sequentially coupled two times to the outer layer of topologically segregated bilayer TentaGel (TG) beads with solid phase peptide synthesis chemistry resulting in beads with increased loading capacity, hydrophilicity, and porosity at the outer layer. We have found that such bead configuration can facilitate ultrahigh-throughput in situ releasable solution-phase screening of OBOC libraries. An encoded releasable OBOC small molecule library was constructed on Jeffamine derivatized TG beads with library compounds tethered to the outer layer via a disulfide linker and coding tags in the interior of the beads. Compound-beads could be efficiently loaded (5-10 min) into a 5 cm diameter Petri dish containing a 10,000-well PDMS microbead cassette, such that over 90% of the microwells were each filled with only one compound-bead. Jurkat T-lymphoid cancer cells suspended in Matrigel were then layered over the microbead cassette to immobilize the compound-beads. After 24 h of incubation at 37 °C, dithiothreitol was added to trigger the release of library compounds. Forty-eight hours later, MTT reporter assay was used to identify regions of reduced cell viability surrounding each positive bead. From a total of about 20,000 beads screened, 3 positive beads were detected and physically isolated for decoding. A strong consensus motif was identified for these three positive compounds. These compounds

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

NASA Astrophysics Data System (ADS)

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

2017-08-01

Alginate is one of the most commonly used dental impression materials; however, its setting time is subject to change depending on storage conditions and duration. This creates problems because consumer carelessness can affect alginate shelf life and quality. In the present study, the setting times of two groups of type I alginate with different expiry dates was tested. The first group consisted of 11 alginate specimens that had not yet passed the expiry date, and the second group consisted of alginates that had passed the expiry date. The alginate powder was mixed with distilled water, poured into a metal ring, and tested with a polished rod of poly-methyl methacrylate. Statistical analysis showed a significant difference (p<0.05) between the setting times of the alginate that had not passed the expiry date (157 ± 3 seconds) and alginate that had passed the expiry date (144 ± 2 seconds). These findings indicate that storage duration can affect alginate setting time.

Calcium gluconate as cross-linker improves survival and shelf life of encapsulated and dried Metarhizium brunneum and Saccharomyces cerevisiae for the application as biological control agents.

PubMed

Humbert, Pascal; Przyklenk, Michael; Vemmer, Marina; Patel, Anant V

2017-02-01

Calcium chloride (CC) is the most common cross-linker for the encapsulation of biocontrol microorganisms in alginate beads. The aim of this study was to evaluate if calcium gluconate (CG) can replace CC as cross-linker and at the same time improve viability after drying and rehydration, hygroscopic properties, shelf life and nutrient supply. Hence, the biocontrol fungi Metarhizium brunneum and Saccharomyces cerevisiae were encapsulated in Ca-alginate beads supplemented with starch. Beads were dried and maximum survival was found in beads cross-linked with CG. Beads prepared with CG showed lower hygroscopic properties, but a higher shelf life for encapsulated fungi. Moreover, we demonstrated that gluconate has a nutritive effect on encapsulated fungi, leading to increased mycelium growth of M. brunneum and to enhanced CO 2 release from beads containing Saccharomyces cerevisiae. The application of CG as cross-linker will pave the way towards increasing drying survival and shelf life of various, especially drying-sensitive microbes.

Wheat germ agglutinin-conjugated chitosan-Ca-alginate microparticles for local colon delivery of 5-FU: development and in vitro characterization.

PubMed

Glavas Dodov, M; Calis, S; Crcarevska, M S; Geskovski, N; Petrovska, V; Goracinova, K

2009-11-03

The aim of this work was to prepare lectin-conjugated chitosan-Ca-alginate microparticles (MPs) loaded with acid-resistant particles of 5-fluorouracil (5-FU) for efficient local treatment of colon cancer. MPs were prepared by a novel one-step spray-drying technique and after wheat germ agglutinin (WGA) conjugation, they were characterized for size, swelling behavior, surface charge, entrapment efficiency and in vitro drug release. Prepared particles were spherical, with 6.73 microg/mg of WGA conjugated onto their surface. The size and zeta potential increased after conjugation, from 6.6 to 14.7 microm and from 9.6 to 15.3 mV, while drug encapsulation was 75.6 and 72.8%, respectively after conjugation. The swelling behavior of beads was mainly determined by properties of the cross-linked chitosan-alginate network. In vitro drug release studies carried out in simulated in vivo conditions with respect to pH, confirmed the potential of the particles to release the drug in a controlled manner. Also, the drug release was not significantly affected by WGA conjugation. The retention of biorecognitive activity of WGA after covalent coupling to MPs was confirmed by haemagglutination test. Functionalized MPs showed excessive mucoadhesiveness in vitro, due to the positive surface charge, pH-dependent swelling of the matrix and lectin-sugar recognition.

Rare Earth Adsorption and Desorption with PEGDA Beads

DOE Data Explorer

Jiao, Yongqin; Brewer, Aaron; Park, Dan

2017-03-01

We synthesized PEGDA polymer hydrogel beads for cell embedding and compared REE biosorption with these beads via a gravity-driven flow through setup. One way to set up a flow through system is by cell encapsulation into polymer beads with a column setup similar to that used in the chromatography industry. To achieve this, we tested PEGDA for cell encapsulation, and tested REE biosorption under both batch mode and a follow through setup based on gravity . For making the cell embedded polymer beads, we used a fluidic device by which homogenous spherical particles of 0.5 to1 mm in diameter were synthesized. The beads are made relatively quickly, and the size of the beads can be controlled. PEGDA beads were polymerized by UV. Tb adsorption experiment was performed with beads with or without cells embedded.

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.

Immobilization of pectin depolymerising polygalacturonase using different polymers.

PubMed

Ur Rehman, Haneef; Aman, Afsheen; Nawaz, Muhammad Asif; Karim, Asad; Ghani, Maria; Baloch, Abdul Hameed; Ul Qader, Shah Ali

2016-01-01

Polygalacturonase catalyses the hydrolysis of pectin substances and widely has been used in food and textile industries. In current study, different polymers such as calcium alginate beads, polyacrylamide gel and agar-agar matrix were screened for the immobilization of polygalacturonase through entrapment technique. Polyacrylamide gel was found to be most promising one and gave maximum (89%) immobilization yield as compared to agar-agar (80%) and calcium alginate beads (46%). The polymers increased the reaction time of polygalacturonase and polymers entrapped polygalacturonases showed maximum pectinolytic activity after 10 min of reaction as compared to free polygalacturonase which performed maximum activity after 5.0 min of reaction time. The temperature of polygalacturonase for maximum enzymatic activity was increased from 45°C to 50°C and 55°C when it was immobilized within agar-agar and calcium alginate beads, respectively. The optimum pH (pH 10) of polygalacturonase was remained same when it was immobilized within polyacrylamide gel and calcium alginate beads, but changed from pH 10 to pH 9.0 after entrapment within agar-agar. Thermal stability of polygalacturonase was improved after immobilization and immobilized polygalacturonases showed higher tolerance against different temperatures as compared to free enzyme. Polymers entrapped polygalacturonases showed good reusability and retained more than 80% of their initial activity during 2nd cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

Polymeric Beads for Organic Coatings

DTIC Science & Technology

1982-10-31

Clear Solid Polymeric Beads A solid polymeric bead is comprised of a sol id mass of polymerized unsaturated polyester/styrene resin mixture . 2. lear...than the current unsaturated polyester resin . For example, a bead male from acrylic resin could be more trans- - parent, more durable and provide more...0.44 Isopropyl Alcohol I 11.26 I 1 .73 60% Wt. Alkyd Resin - Volume I 251.26 i 30.52 " Sol ids 51% 1 I Anti.-Skinning Agent I 0.90 I 0.12 Mineral

Review: peripheral nerve regeneration using non-tubular alginate gel crosslinked with covalent bonds.

PubMed

Hashimoto, Tadashi; Suzuki, Yoshihisa; Suzuki, Kyoko; Nakashima, Toshihide; Tanihara, Masao; Ide, Chizuka

2005-06-01

We have developed a nerve regeneration material consisting of alginate gel crosslinked with covalent bonds. in the first part of this study, we attempted to analyze nerve regeneration through alginate gel in the early stages within 2 weeks. in the second part, we tried to regenerate cat peripheral nerve by using alginate tubular or non-tubular nerve regeneration devices, and compared their efficacies. Four days after surgery, regenerating axons grew without Schwann cell investment through the partially degraded alginate gel, being in direct contact with the alginate without a basal lamina covering. One to 2 weeks after surgery, regenerating axons were surrounded by common Schwann cells, forming small bundles, with some axons at the periphery being partly in direct contact with alginate. At the distal stump, numerous Schwann cells had migrated into the alginate 8-14 days after surgery. Remarkable restorations of the 50-mm gap in cat sciatic nerve were obtained after a long term by using tubular or non-tubular nerve regeneration material consisting mainly of alginate gel. However, there was no significant difference between both groups at electrophysiological and morphological evaluation. Although, nowadays, nerve regeneration materials being marketed mostly have a tubular structure, our results suggest that the tubular structure is not indispensable for peripheral nerve regeneration.

Selective digestion of Ba2+/Ca2+ alginate gel microdroplets for single-cell handling

NASA Astrophysics Data System (ADS)

Odaka, Masao; Hattori, Akihiro; Matsuura, Kenji; Yasuda, Kenji

2018-06-01

Cells encapsuled by polymer microdroplets are an effective platform for the identification and separation of individual cells for single-cell-based analysis. However, a key challenge is to maintain and release the captured cells in the microdroplets selectively, nondestructively, and noninvasively. We developed a simple method of encapsulating cells in alginate microdroplets having different digestion characteristics. Cells were diluted with an alginate polymer of sol state and encapsulated into microdroplets with Ba2+ and Ca2+ by a spray method. When a chelating buffer was applied, alginate gel microdroplets were digested according to the difference in chelating efficiency of linkage-divalent cations; hence, two types of alginate microdroplets were formed. Moreover, we examined the capability of the alginate gel to exchange linkage-divalent cations and found that both Ca2+ exchange in Ba-alginate microdroplets and Ba2+ exchange in Ca-alginate microdroplets occurred. These results indicate that the potential applications of a mixture of alginate microdroplets with different divalent cations control the selective digestion of microdroplets to improve the high-throughput, high-content microdroplet-based separation, analysis, or storage of single cells.

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

PubMed Central

Bai, Shaofeng; Chen, Huahai; Zhu, Liying; Liu, Wei; Yu, Hongwei D.; Wang, Xin; Yin, Yeshi

2017-01-01

Alginates pertain to organic polysaccharides that have been extensively used in food- and medicine-related industries. The present study obtained alginates from an alginate overproducing Pseudomonas aeruginosa PAO1 mutant by screening transposon mutagenesis libraries. The interaction between bacterial and seaweed alginates and gut microbiota were further studied by using an in vitro batch fermentation system. Thin-layer chromatography (TLC) analysis indicated that both bacterial and seaweed alginates can be completely degraded by fecal bacteria isolated from study volunteers, indicating that a minor structural difference between bacterial and seaweed alginates (O-acetylation and lack of G-G blocks) didn’t affect the digestion of alginates by human microbiota. Although, the digestion of bacterial and seaweed alginates was attributed to different Bacteroides xylanisolvens strains, they harbored similar alginate lyase genes. Genus Bacteroides with alginate-degrading capability were enriched in growth medium containing bacterial or seaweed alginates after in vitro fermentation. Short-chain fatty acid (SCFA) production in both bacterial and seaweed alginates was also comparable, but was significantly higher than the same medium using starch. In summary, the present study has isolated an alginate-overproducing P. aeruginosa mutant strain. Both seaweed and bacterial alginates were degraded by human gut microbiota, and their regulatory function on gut microbiota was similar. PMID:28170428

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

PubMed

Bai, Shaofeng; Chen, Huahai; Zhu, Liying; Liu, Wei; Yu, Hongwei D; Wang, Xin; Yin, Yeshi

2017-01-01

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

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

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

Oscillatory magnetic tweezers based on ferromagnetic beads and simple coaxial coils

NASA Astrophysics Data System (ADS)

Trepat, Xavier; Grabulosa, Mireia; Buscemi, Lara; Rico, Fèlix; Fabry, Ben; Fredberg, Jeffrey J.; Farré, Ramon

2003-09-01

We report the design and validation of simple magnetic tweezers for oscillating ferromagnetic beads in the piconewton and nanometer scales. The system is based on a single pair of coaxial coils operating in two sequential modes: permanent magnetization of the beads through a large and brief pulse of magnetic field and generation of magnetic gradients to produce uniaxial oscillatory forces. By using this two step method, the magnetic moment of the beads remains constant during measurements. Therefore, the applied force can be computed and varies linearly with the driving signal. No feedback control is required to produce well defined force oscillations over a wide bandwidth. The design of the coils was optimized to obtain high magnetic fields (280 mT) and gradients (2 T/m) with high homogeneity (5% variation) within the sample. The magnetic tweezers were implemented in an inverted optical microscope with a videomicroscopy-based multiparticle tracking system. The apparatus was validated with 4.5 μm magnetite beads obtaining forces up to ˜2 pN and subnanometer resolution. The applicability of the device includes microrheology of biopolymer and cell cytoplasm, molecular mechanics, and mechanotransduction in living cells.

Production and characterization of alginate microcapsules produced by a vibrational encapsulation device.

PubMed

Mazzitelli, S; Tosi, A; Balestra, C; Nastruzzi, C; Luca, G; Mancuso, F; Calafiore, R; Calvitti, M

2008-09-01

The optimization, through a Design of Experiments (DoE) approach, of a microencapsulation procedure for isolated neonatal porcine islets (NPI) is described. The applied method is based on the generation of monodisperse droplets by a vibrational nozzle. An alginate/polyornithine encapsulation procedure, developed and validated in our laboratory for almost a decade, was used to embody pancreatic islets. We analyzed different experimental parameters including frequency of vibration, amplitude of vibration, polymer pumping rate, and distance between the nozzle and the gelling bath. We produced calcium-alginate gel microbeads with excellent morphological characteristics as well as a very narrow size distribution. The automatically produced microcapsules did not alter morphology, viability and functional properties of the enveloped NPI. The optimization of this automatic procedure may provide a novel approach to obtain a large number of batches possibly suitable for large scale production of immunoisolated NPI for in vivo cell transplantation procedures in humans.

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

Metal-Containing Polystyrene Beads as Standards for Mass Cytometry.

PubMed

Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Kinach, Robert; Dai, Sheng; Thickett, Stuart C; Tanner, Scott; Winnik, Mitchell A

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.

The release of alginate lyase from growing Pseudomonas syringae pathovar phaseolicola

NASA Technical Reports Server (NTRS)

Ott, C. M.; Day, D. F.; Koenig, D. W.; Pierson, D. L.

2001-01-01

Pseudomonas syringae pathovar phaseolicola, which produces alginate during stationary growth phase, displayed elevated extracellular alginate lyase activity during both mid-exponential and late-stationary growth phases of batch growth. Intracellular activity remained below 22% of the total activity during exponential growth, suggesting that alginate lyase has an extracellular function for this organism. Extracellular enzyme activity in continuous cultures, grown in either nutrient broth or glucose-simple salts medium, peaked at 60% of the washout rate, although nutrient broth-grown cultures displayed more than twice the activity per gram of cell mass. These results imply that growth rate, nutritional composition, or both initiate a release of alginate lyase from viable P. syringae pv. phaseolicola, which could modify its entrapping biofilm.

Bilateral PLA/alginate membranes for the prevention of postsurgical adhesions.

PubMed

Kessler, Martina; Esser, Eva; Groll, Jürgen; Tessmar, Jörg

2016-11-01

A bilateral barrier membrane for the prevention of postsurgical adhesions was developed. Thereby, a smooth PLA side was supposed to keep the affected tissues glidingly separated, while a mucoadhesive side made of alginate was meant to keep the barrier resident on the site of injury so that suturing becomes redundant or at least the membrane stays long enough to facilitate surgical handling. Because hydrophilic alginate and lipophilic PLA films show only low cohesion, solution electrospun meshes of PLA and PLA-PEG-PLA triblock copolymers with varying poly(ethylene glycol) [PEG] content were investigated as cohesion promoter to avoid an easy separation of the functionally different layers. Using direct electrospinning onto the PLA film, a modified contact surface of the mesh was created, which allowed the tested alginate solutions (3%, 5%) to infiltrate to different extents. Thereby, an increasing content of hydrophilic PEG within the mesh copolymer and a lower alginate concentration facilitated the infiltration. As a result, the PLA film with a PLA35k-PEG10k-PLA35k (racemic PLA chains) mesh and an alginate layer cast from a 3% alginate solution appeared to be the most effective combination as examined by means of a t peel test, a mucoadhesion test, a tensile test and optical evaluations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1563-1570, 2016. © 2015 Wiley Periodicals, Inc.

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

PubMed

Khampieng, Thitikan; Aramwit, Pornanong; Supaphol, Pitt

2015-09-01

In this study, silk sericin loaded alginate nanoparticles were prepared by the emulsification method followed by internal crosslinking. The effects of various silk sericin loading concentration on particle size, shape, thermal properties, and release characteristics were investigated. The initial silk sericin loadings of 20, 40, and 80% w/w to polymer were incorporated into these alginate nanoparticles. SEM images showed a spherical shape and small particles of about 71.30-89.50 nm. TGA analysis showed that thermal stability slightly increased with increasing silk sericin loadings. FTIR analysis suggested interactions between alginate and silk sericin in the nanoparticles. The release study was performed in acetate buffer at normal skin conditions (pH 5.5; 32 °C). The release profiles of silk sericin exhibited initial rapid release, consequently with sustained release. These silk sericin loaded alginate nanoparticles were further incorporated into topical hydrogel and their anti-inflammatory properties were studied using carrageenan-induced paw edema assay. The current study confirms the hypothesis that the application of silk sericin loaded alginate nanoparticle gel can inhibit inflammation induced by carrageenan. Copyright © 2015 Elsevier B.V. All rights reserved.

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

PubMed

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

2017-06-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jingquan; Rouse, Sarah L.; Li, Dianfan

2014-08-01

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

Link between alginate reaction front propagation and general reaction diffusion theory.

PubMed

Braschler, Thomas; Valero, Ana; Colella, Ludovica; Pataky, Kristopher; Brugger, Jürgen; Renaud, Philippe

2011-03-15

We provide a common theoretical framework reuniting specific models for the Ca(2+)-alginate system and general reaction diffusion theory along with experimental validation on a microfluidic chip. As a starting point, we use a set of nonlinear, partial differential equations that are traditionally solved numerically: the Mikkelsen-Elgsaeter model. Applying the traveling-wave hypothesis as a major simplification, we obtain an analytical solution. The solution indicates that the fundamental properties of the alginate reaction front are governed by a single dimensionless parameter λ. For small λ values, a large depletion zone accompanies the reaction front. For large λ values, the alginate reacts before having the time to diffuse significantly. We show that the λ parameter is of general importance beyond the alginate model system, as it can be used to classify known solutions for second-order reaction diffusion schemes, along with the novel solution presented here. For experimental validation, we develop a microchip model system, in which the alginate gel formation can be carried out in a highly controlled, essentially 1D environment. The use of a filter barrier enables us to rapidly renew the CaCl(2) solution, while maintaining flow speeds lower than 1 μm/s for the alginate compartment. This allows one to impose an exactly known bulk CaCl(2) concentration and diffusion resistance. This experimental model system, taken together with the theoretical development, enables the determination of the entire set of physicochemical parameters governing the alginate reaction front in a single experiment.

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

PubMed

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

2016-07-01

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

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.

Bead mediated separation of microparticles in droplets

PubMed Central

Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A.

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead’s solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield. PMID:28282412

Production, deformation and mechanical investigation of magnetic alginate capsules

NASA Astrophysics Data System (ADS)

Zwar, Elena; Kemna, Andre; Richter, Lena; Degen, Patrick; Rehage, Heinz

2018-02-01

In this article we investigated the deformation of alginate capsules in magnetic fields. The sensitivity to magnetic forces was realised by encapsulating an oil in water emulsion, where the oil droplets contained dispersed magnetic nanoparticles. We solved calcium ions in the aqueous emulsion phase, which act as crosslinking compounds for forming thin layers of alginate membranes. This encapsulating technique allows the production of flexible capsules with an emulsion as the capsule core. It is important to mention that the magnetic nanoparticles were stable and dispersed throughout the complete process, which is an important difference to most magnetic alginate-based materials. In a series of experiments, we used spinning drop techniques, capsule squeezing experiments and interfacial shear rheology in order to determine the surface Young moduli, the surface Poisson ratios and the surface shear moduli of the magnetically sensitive alginate capsules. In additional experiments, we analysed the capsule deformation in magnetic fields. In spinning drop and capsule squeezing experiments, water droplets were pressed out of the capsules at elevated values of the mechanical load. This phenomenon might be used for the mechanically triggered release of water-soluble ingredients. After drying the emulsion-filled capsules, we produced capsules, which only contained a homogeneous oil phase with stable suspended magnetic nanoparticles (organic ferrofluid). In the dried state, the thin alginate membranes of these particles were rather rigid. These dehydrated capsules could be stored at ambient conditions for several months without changing their properties. After exposure to water, the alginate membranes rehydrated and became flexible and deformable again. During this swelling process, water diffused back in the capsule. This long-term stability and rehydration offers a great spectrum of different applications as sensors, soft actuators, artificial muscles or drug delivery systems.

Effect of alginate in patients with GERD hiatal hernia matters.

PubMed

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

2017-10-01

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

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.

BeadArray Expression Analysis Using Bioconductor

PubMed Central

Ritchie, Matthew E.; Dunning, Mark J.; Smith, Mike L.; Shi, Wei; Lynch, Andy G.

2011-01-01

Illumina whole-genome expression BeadArrays are a popular choice in gene profiling studies. Aside from the vendor-provided software tools for analyzing BeadArray expression data (GenomeStudio/BeadStudio), there exists a comprehensive set of open-source analysis tools in the Bioconductor project, many of which have been tailored to exploit the unique properties of this platform. In this article, we explore a number of these software packages and demonstrate how to perform a complete analysis of BeadArray data in various formats. The key steps of importing data, performing quality assessments, preprocessing, and annotation in the common setting of assessing differential expression in designed experiments will be covered. PMID:22144879

Single bead-based electrochemical biosensor.

PubMed

Liu, Changchun; Schrlau, Michael G; Bau, Haim H

2009-12-15

A simple, robust, single bead-based electrochemical biosensor was fabricated and characterized. The sensor's working electrode consists of an electrochemically etched platinum wire, with a nominal diameter of 25 microm, hermetically heat-fusion sealed in a pulled glass capillary (micropipette). The sealing process does not require any epoxy or glue. A commercially available, densely functionalized agarose bead was mounted on the tip of the etched platinum wire. The use of a pre-functionalized bead eliminates the tedious and complicated surface functionalization process that is often the bottleneck in the development of electrochemical biosensors. We report on the use of a biotin agarose bead-based, micropipette, electrochemical (Bio-BMP) biosensor to monitor H(2)O(2) concentration and the use of a streptavidin bead-based, micropipette, electrochemical (SA-BMP) biosensor to detect DNA amplicons. The Bio-BMP biosensor's response increased linearly as the H(2)O(2) concentration increased in the range from 1 x 10(-6) to 1.2 x10(-4)M with a detection limit of 5 x 10(-7)M. The SA-BMP was able to detect the amplicons of 1pg DNA template of B. Cereus bacteria, thus providing better detection sensitivity than conventional gel-based electropherograms.

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

Heavy metal removal by caustic-treated yeast immobilized in alginate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Y.; Wilkins, E.

1995-12-31

Saccharomyces cerevisiae yeast biomass was treated with hot alkali to increase its biosorption capacity for heavy metals and then was immobilized in alginate gel. Biosorption capacities for Cu{sup 2+}, Cd{sup 2+}, and Zn{sup 2+} on alginate gel, native yeast, native yeast immobilized in alginate gel, and caustic-treated yeast immobilized in alginate gel were all compared. Immobilized yeasts could be reactivated and reused in a manner similar to the ion exchange resins. Immobilized caustic-treated yeast has high heavy metal biosorption capacity and high metal removal efficiency in a rather wide acidic pH region. The biosorption isotherm of immobilized caustic-treated yeast wasmore » studied, and empirical equations were obtained. The initial pH of polluted water affected the metal removal efficiency significantly, and the equilibrium biosorption capacity seemed to be temperature independent at lower initial metal concentrations.« less

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

Mineralized alginate hydrogels using marine carbonates for bone tissue engineering applications.

PubMed

Diaz-Rodriguez, P; Garcia-Triñanes, P; Echezarreta López, M M; Santoveña, A; Landin, M

2018-09-01

The search for an ideal bone tissue replacement has led to the development of new composite materials designed to simulate the complex inorganic/organic structure of bone. The present work is focused on the development of mineralized calcium alginate hydrogels by the addition of marine derived calcium carbonate biomineral particles. Following a novel approach, we were able to obtain calcium carbonate particles of high purity and complex micro and nanostructure dependent on the source material. Three different types of alginates were selected to develop inorganic/organic scaffolds in order to correlate alginate composition with scaffold properties and cell behavior. The incorporation of calcium carbonates into alginate networks was able to promote extracellular matrix mineralization and osteoblastic differentiation of mesenchymal stem cells when added at 7 mg/ml. We demonstrated that the selection of the alginate type and calcium carbonate origin is crucial to obtain adequate systems for bone tissue engineering as they modulate the mechanical properties and cell differentiation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microfluidic Synthesis of Ca-Alginate Microcapsules for Self-Healing of Bituminous Binder.

PubMed

Shu, Benan; Wu, Shaopeng; Dong, Lijie; Wang, Qing; Liu, Quantao

2018-04-19

This work aims to develop an original alginate micro-emulsion combining with droplets microfluidic method to produce multinuclear Ca-alginate microcapsules containing rejuvenator for the self-healing of bituminous binder. The sizes of the Ca-alginate microcapsules could be easily controlled by tuning flow rates of the continuous and dispersed phases. The addition of a surfactant Tween80 not only improved the stability of the emulsion, but it also effectively reduced the size of the microcapsules. Size predictive mathematical model of the microcapsules was proposed through the analysis of fluid force. Optical microscope and remote Fourier infrared test confirmed the multinuclear structure of Ca-alginate microcapsules. Thermogravimetric analysis showed that the microcapsules coated with nearly 40% rejuvenator and they remained intact during the preparation of bitumen specimen at 135 °C. Micro self-healing process of bituminous binder with multinuclear Ca-alginate microcapsules containing rejuvenator was monitored and showed enhanced self-healing performance. Tensile stress-recovery test revealed that the recovery rate increased by 32.08% (in the case of 5% microcapsules), which meant that the Ca-alginate microcapsules containing rejuvenator could effectively enhance the self-healing property of bituminous binder.

Bead lightning formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludwig, G.O.; Saba, M.M.F.; Division of Space Geophysics, National Space Research Institute, 12227-010, Sao Jose dos Campos, SP

2005-09-15

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

Localized transfection on arrays of magnetic beads coated with PCR products.

PubMed

Isalan, Mark; Santori, Maria Isabel; Gonzalez, Cayetano; Serrano, Luis

2005-02-01

High-throughput gene analysis would benefit from new approaches for delivering DNA or RNA into cells. Here we describe a simple system that allows any molecular biology laboratory to carry out multiple, parallel cell transfections on microscope coverslip arrays. By using magnetically defined positions and PCR product-coated paramagnetic beads, we achieved transfection in a variety of cell lines. Beads may be added to the cells at any time, allowing both spatial and temporal control of transfection. Because the beads may be coated with more than one gene construct, the method can be used to achieve cotransfection within single cells. Furthermore, PCR-generated mutants may be conveniently screened, bypassing cloning and plasmid purification steps. We illustrated the applicability of the method by screening combinatorial peptide libraries, fused to GFP, to identify previously unknown cellular localization motifs. In this way, we identified several localizing peptides, including structured localization signals based around the scaffold of a single C2H2 zinc finger.

The profile of adsorbed plasma and serum proteins on methacrylic acid copolymer beads: Effect on complement activation.

PubMed

Wells, Laura A; Guo, Hongbo; Emili, Andrew; Sefton, Michael V

2017-02-01

Polymer beads made of 45% methacrylic acid co methyl methacrylate (MAA beads) promote vascular regenerative responses in contrast to control materials without methacrylic acid (here polymethyl methacrylate beads, PMMA). In vitro and in vivo studies suggest that MAA copolymers induce differences in macrophage phenotype and polarization and inflammatory responses, presumably due to protein adsorption differences between the beads. To explore differences in protein adsorption in an unbiased manner, we used high resolution shotgun mass spectrometry to identify and compare proteins that adsorb from human plasma or serum onto MAA and PMMA beads. From plasma, MAA beads adsorbed many complement proteins, such as C1q, C4-related proteins and the complement inhibitor factor H, while PMMA adsorbed proteins, such as albumin, C3 and apolipoproteins. Because of the differences in complement protein adsorption, follow-up studies focused on using ELISA to assess complement activation. When incubated in serum, MAA beads generated significantly lower levels of soluble C5b9 and C3a/C3a desarg in comparison to PMMA beads, indicating a decrease in complement activation with MAA beads. The differences in adsorbed protein on the two materials likely alter subsequent cell-material interactions that ultimately result in different host responses and local vascularization. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2018-02-01

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

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

PubMed

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

2017-10-07

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

Mechanical Properties of Hydrogel Beads

NASA Astrophysics Data System (ADS)

Criddle, Keely; Benns, Thomas; Shorts, Dan; Feitosa, Klebert

2015-03-01

Fragile solids made of dense disordered packing of bubbles, droplets and grains are able to withstand small stresses by virtue of system-wide force chains that lock the system into a jammed state. The nature of the jamming transition in such soft materials has been the subject of intense research, but despite much effort, a deep understanding remains elusive. In this experiment we study the mechanical properties of hydrogel beads to exploit them as force transducers in densely packed systems. The experiment consists of applying uniaxial planar compressions on the beads, and correlating the force to the bead's strain and contact area. The results show that while the strain scales linearly with the diameter of the contact area, the force and strain are found to obey a power law relation with two distinct exponents at small and large strains. This result leads to a power law dependence of the force on the contact area diameter of the compressed bead.

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…

Stimulation of wound healing by positively charged dextran beads depends upon clustering of beads and cells in close proximity to the wound.

PubMed

Tawil, N J; Connors, D; Gies, D; Bennett, S; Gruskin, E; Mustoe, T

1999-01-01

We have previously shown that positively charged dextran (DEAE A25) increases wound breaking strength in linear incisions in rats and nonhuman primates at days 10-14 postwounding. In this article, we examined the cellular responses to different types of charged dextran beads (DEAE A50 and Cytodex-1) in culture studies and in rat incisional wounds. We show that Cytodex 1 and DEAE A50 beads also increased wound breaking strength in a rat linear incisional model. However, the increase was approximately 30-40% less than that observed in wounds treated with DEAE A25 beads. The main distinction between the three types of beads was the presence of bead clusters observed in tissue sections. Wounds treated with DEAE A25 beads formed distinct clusters while both Cytodex 1 and DEAE A50 beads clustered to a lesser extent or failed to cluster at all. We propose that the different types of charged dextran beads improve healing by promoting cell adhesion and encouraging proliferation in close proximity to the wound. We also hypothesize that the 30-40% improvement in wound breaking strength seen with DEAE A25 beads compared to other types of charged dextran beads (DEAE A50 and Cytodex-1) originates from the unique characteristic of DEAE A25 beads in forming cell-bead aggregates adjacent to the wounded area. This clustering, in turn, affects the distribution of cells infiltrating the wounded area (such as macrophages) during the healing process and, as a consequence, alters the distribution of matrix molecules and growth factors secreted by these cells.

Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells.

PubMed

Rampini, S; Kilinc, D; Li, P; Monteil, C; Gandhi, D; Lee, G U

2015-08-21

Nonlinear magnetophoresis (NLM) is a novel approach for on-chip transport and separation of superparamagnetic (SPM) beads, based on a travelling magnetic field wave generated by the combination of a micromagnet array (MMA) and an applied rotating magnetic field. Here, we present two novel MMA designs that allow SPM beads to be focused, sorted, and separated on-chip. Converging MMAs were used to rapidly collect the SPM beads from a large region of the chip and focus them into synchronised lines. We characterise the collection efficiency of the devices and demonstrate that they can facilitate on-chip analysis of populations of SPM beads using a single-point optical detector. The diverging MMAs were used to control the transport of the beads and to separate them based on their size. The separation efficiency of these devices was determined by the orientation of the magnetisation of the micromagnets relative to the external magnetic field and the size of the beads and relative to that of micromagnets. By controlling these parameters and the rotation of the external magnetic field we demonstrated the controlled transport of SPM bead-labelled single MDA-MB-231 cells. The use of these novel MMAs promises to allow magnetically-labelled cells to be efficiently isolated and then manipulated on-chip for analysis with high-resolution chemical and physical techniques.

Preferential localization of Lactococcus lactis cells entrapped in a caseinate/alginate phase separated system.

PubMed

Léonard, Lucie; Gharsallaoui, Adem; Ouaali, Fahima; Degraeve, Pascal; Waché, Yves; Saurel, Rémi; Oulahal, Nadia

2013-09-01

This study aimed to entrap bioprotective lactic acid bacteria in a sodium caseinate/sodium alginate aqueous two-phase system. Phase diagram at pH=7 showed that sodium alginate and sodium caseinate were not miscible when their concentrations exceeded 1% (w/w) and 6% (w/w), respectively. The stability of the caseinate/alginate two-phase system was also checked at pH values of 6.0 and 5.5. Lactococcus lactis subsp. lactis LAB3 cells were added in a 4% (w/w) caseinate/1.5% (w/w) alginate two-phase system at pH=7. Fluorescence microscopy allowed to observe that the caseinate-rich phase formed droplets dispersed in a continuous alginate-rich phase. The distribution of bacteria in such a system was observed by epifluorescence microscopy: Lc. lactis LAB3 cells stained with Live/Dead(®) Baclight kit™ were located exclusively in the protein phase. Since zeta-potential measurements indicated that alginate, caseinate and bacterial cells all had an overall negative charge at pH 7, the preferential adhesion of LAB cells was assumed to be driven by hydrophobic effect or by depletion phenomena in such biopolymeric systems. Moreover, LAB cells viability was significantly higher in the ternary mixture obtained in the presence of both caseinate and alginate than in single alginate solution. Caseinate/alginate phase separated systems appeared thus well suited for Lc. lactis LAB3 cells entrapment. Copyright © 2013 Elsevier B.V. All rights reserved.

Microfabrication of proangiogenic cell-laden alginate-g-pyrrole hydrogels.

PubMed

DeVolder, Ross J; Zill, Andrew T; Jeong, Jae H; Kong, Hyunjoon

2012-11-01

Cells have been extensively studied for their uses in various therapies because of their capacities to produce therapeutic proteins and recreate new tissues. It has often been suggested that the efficacy of cell therapies can greatly be improved through the ability to localize and regulate cellular activities at a transplantation site; however, the technologies for this control are lacking. Therefore, this study reports a cell-Laden hydrogel patch engineered to support the proliferation and angiogenic growth factor expression of cells adhered to their surfaces, and to further promote neovascularization. Hydrogels consisting of alginate chemically linked with pyrrole units, termed alginate-g-pyrrole, were prepared through an oxidative cross-linking reaction between pyrrole units. Fibroblasts adhered to the alginate-g-pyrrole hydrogels, and exhibited increased proliferation and overall vascular endothelial growth factor (VEGF) expression, compared to those on pyrrole-free hydrogels. Furthermore, the alginate-g-pyrrole hydrogel surfaces were modified to present microposts, subsequently increasing the amount of pyrrole units on their surfaces. Cells adhered to the microfabricated gel surfaces exhibited increased proliferation and overall VEGF expression proportional to the density of the microposts. The resulting micropatterned alginate-g-pyrrole hydrogels exhibited increases in the size and density of mature blood vessels when implanted on chick chorioallantoic membranes (CAMs). The hydrogel system developed in this study will be broadly useful for improving the efficacy of a wide array of cell-based wound healing and tissue regenerative therapies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applying multi-criteria analysis for preliminary assessment of the properties of alginate immobilized Myriophyllum spicatum in lake water samples.

PubMed

Milojković, Jelena V; Popović-Djordjević, Jelena B; Pezo, Lato L; Brčeski, Ilija D; Kostić, Aleksandar Ž; Milošević, Vladan D; Stojanović, Mirjana D

2018-05-11

The preliminary assessment of the properties of alginate immobilized aquatic weed Myriophyllum spicatum beads-MsAlg in a multi-element system of nine Serbian lakes water samples was done. Herein, the results obtained in the biosorption experiment with MsAlg contents of twenty-two elements analysed by inductively coupled plasma-optical emission spectrometry, biosorption capacity, element removal efficiency, total hardness (TH) and quality index of water (WQI) are presented. Scanning electron microscopy with energy dispersive X-ray spectroscopy was used for the characterization of M. spicatum and its beads. The study showed that aluminium, magnesium and strontium were adsorbed by MsAlg in the water samples from all examined lakes; barium and iron in the water samples from six lakes. The overall average efficiency of MsAlg in biosorption of elements was in the following order: Al > Ba > Sr > Fe > Mg (58.6, 51.7, 48.2, 23.9 and 17.7%, respectively). The increase of TH and WQI values after the biosorption was noticed in all studied lake water samples. The most significant correlations for pH were regarding the contents of B, Mg and Ca, whereas WQI was highly correlated to the contents of B and Mg, and pH. The complexity of the obtained data was explained by Cluster Analysis and Principal Component Analysis, which showed good discrimination capabilities between the water samples taken from different locations. Considering that the invasive M. spicatum is natural, widespread and that its immobilization is cheap and eco-friendly, presented findings could be helpful in further assessment of MsAlg beads for its potential use as biofilter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development and evaluation of floating alginate microspheres for oral delivery of anthocyanins - A preliminary investigation.

PubMed

Celli, Giovana B; Ghanem, Amyl; Brooks, Marianne S

2017-05-01

The goal of this study was to develop floating microspheres that could be used as gastroretentive systems for the delivery of anthocyanins (ACNs). These compounds are absorbed in the stomach and small intestine, and insufficient residence time in these organs could result in limited absorption and contribute to degradation. The microparticles containing freeze-dried haskap berry extract (321.96 ± 8.35 mg cyanidin 3-glucoside equivalents per g) were prepared by ionotropic gelation of alginate (9%, w/w) with calcium ions (CaCl 2 at 2%, w/v) in the gelation bath, with calcium carbonate as the gas-generating compound (added at different ratios in the alginate/extract mixture). The effect of acetic acid concentration (2 and 10%, v/v) in the gelation medium was investigated. Increasing the carbonate : alginate weigh ratio from 0 to 3:4 resulted in different degrees of floatability, larger particles, higher encapsulation efficiency, and lower amount of ACN released. The power law equation fitted the experimental data well, indicating that release occurred mainly by diffusion. This is the first time floating microspheres are proposed as gastroretentive platforms for the delivery of ACNs.

Low intensity pulse ultrasound stimulate chondrocytes growth in a 3-D alginate scaffold through improved porosity and permeability.

PubMed

Guo, Gepu; Lu, Lu; Ji, Hongfei; Ma, Yong; Dong, Rui; Tu, Juan; Guo, Xiasheng; Qiu, Yuanyuan; Wu, Junru; Zhang, Dong

2015-04-01

A 3-D scaffold culture system has been used to promote in producing functional chondrocytes for repairing damaged cartilage. In the present study, the low intensity pulse ultrasound (LIPUS) (P(-)=0, 0.055, 0.085 and 0.11 MPa) was applied to improve the porosity and permeability of a 3-D alginate scaffold which was beneficial for the nutrition supply and metabolism during cell growth in 3-D alginate scaffold. The porosity and permeability of the scaffold was quantitatively analyzed based on scanning electron microscopy examination and fluorescence image observation. The results suggest that, for the scaffold exposed to LIPUS, its porosity and permeability could be significantly enhanced by the increasing LIPUS amplitude, which might be induced by the microstreaming shear stress generated by ultrasound-driven microbubble oscillations. Furthermore, the assessments of cell proliferation and collagen II expression confirmed that chondrocytes growth could be effectively promoted in 3-D alginate scaffolds treated by LIPUS, because of the improved scaffold porosity and permeability might benefit cell growth space and nutrition supply. It should also be noticed that appropriate LIPUS driving parameters should be adapted to achieve optimized chondrocytes culture effect in 3-D alginate scaffold. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

Brownian dynamics simulations with stiff finitely extensible nonlinear elastic-Fraenkel springs as approximations to rods in bead-rod models.

PubMed

Hsieh, Chih-Chen; Jain, Semant; Larson, Ronald G

2006-01-28

A very stiff finitely extensible nonlinear elastic (FENE)-Fraenkel spring is proposed to replace the rigid rod in the bead-rod model. This allows the adoption of a fast predictor-corrector method so that large time steps can be taken in Brownian dynamics (BD) simulations without over- or understretching the stiff springs. In contrast to the simple bead-rod model, BD simulations with beads and FENE-Fraenkel (FF) springs yield a random-walk configuration at equilibrium. We compare the simulation results of the free-draining bead-FF-spring model with those for the bead-rod model in relaxation, start-up of uniaxial extensional, and simple shear flows, and find that both methods generate nearly identical results. The computational cost per time step for a free-draining BD simulation with the proposed bead-FF-spring model is about twice as high as the traditional bead-rod model with the midpoint algorithm of Liu [J. Chem. Phys. 90, 5826 (1989)]. Nevertheless, computations with the bead-FF-spring model are as efficient as those with the bead-rod model in extensional flow because the former allows larger time steps. Moreover, the Brownian contribution to the stress for the bead-FF-spring model is isotropic and therefore simplifies the calculation of the polymer stresses. In addition, hydrodynamic interaction can more easily be incorporated into the bead-FF-spring model than into the bead-rod model since the metric force arising from the non-Cartesian coordinates used in bead-rod simulations is absent from bead-spring simulations. Finally, with our newly developed bead-FF-spring model, existing computer codes for the bead-spring models can trivially be converted to ones for effective bead-rod simulations merely by replacing the usual FENE or Cohen spring law with a FENE-Fraenkel law, and this convertibility provides a very convenient way to perform multiscale BD simulations.

Brownian dynamics simulations with stiff finitely extensible nonlinear elastic-Fraenkel springs as approximations to rods in bead-rod models

NASA Astrophysics Data System (ADS)

Hsieh, Chih-Chen; Jain, Semant; Larson, Ronald G.

2006-01-01

A very stiff finitely extensible nonlinear elastic (FENE)-Fraenkel spring is proposed to replace the rigid rod in the bead-rod model. This allows the adoption of a fast predictor-corrector method so that large time steps can be taken in Brownian dynamics (BD) simulations without over- or understretching the stiff springs. In contrast to the simple bead-rod model, BD simulations with beads and FENE-Fraenkel (FF) springs yield a random-walk configuration at equilibrium. We compare the simulation results of the free-draining bead-FF-spring model with those for the bead-rod model in relaxation, start-up of uniaxial extensional, and simple shear flows, and find that both methods generate nearly identical results. The computational cost per time step for a free-draining BD simulation with the proposed bead-FF-spring model is about twice as high as the traditional bead-rod model with the midpoint algorithm of Liu [J. Chem. Phys. 90, 5826 (1989)]. Nevertheless, computations with the bead-FF-spring model are as efficient as those with the bead-rod model in extensional flow because the former allows larger time steps. Moreover, the Brownian contribution to the stress for the bead-FF-spring model is isotropic and therefore simplifies the calculation of the polymer stresses. In addition, hydrodynamic interaction can more easily be incorporated into the bead-FF-spring model than into the bead-rod model since the metric force arising from the non-Cartesian coordinates used in bead-rod simulations is absent from bead-spring simulations. Finally, with our newly developed bead-FF-spring model, existing computer codes for the bead-spring models can trivially be converted to ones for effective bead-rod simulations merely by replacing the usual FENE or Cohen spring law with a FENE-Fraenkel law, and this convertibility provides a very convenient way to perform multiscale BD simulations.

Size of the Dynamic Bead in Polymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 modelmore » 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.« less

Self-organizing magnetic beads for biomedical applications

NASA Astrophysics Data System (ADS)

Gusenbauer, Markus; Kovacs, Alexander; Reichel, Franz; Exl, Lukas; Bance, Simon; Özelt, Harald; Schrefl, Thomas

2012-03-01

In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We developed a simulation tool that combines micromagnetics and discrete particle dynamics, in order to design micropost arrays made of interacting beads. The simulation takes into account the viscous drag of the blood flow, magnetostatic interactions between the magnetic beads and gradient forces from external aligned magnets. We developed a particle-particle particle-mesh method for effective computation of the magnetic force and torque acting on the particles.

Bacterial supersystem for alginate import/metabolism and its environmental and bioenergy applications.

PubMed

Hashimoto, Wataru; Kawai, Shigeyuki; Murata, Kousaku

2010-01-01

Distinct from most alginate-assimilating bacteria that secrete polysaccharide lyases extracellularly, a gram-negative bacterium, Sphingomonas sp. A1 (strain A1), can directly incorporate alginate into its cytoplasm, without degradation, through a "superchannel" consisting of a mouth-like pit on the cell surface, periplasmic binding proteins, and a cytoplasmic membrane-bound ATP-binding cassette transporter. Flagellin homologues function as cell surface alginate receptors essential for expressing the superchannel. Cytoplasmic alginate lyases with different substrate specificities and action modes degrade the polysaccharide to its constituent monosaccharides. The resultant monosaccharides, α-keto acids, are converted to a reduced form by NADPH-dependent reductase, and are finally metabolized in the TCA cycle. Transplantation of the strain A1 superchannel to xenobiotic-degrading sphingomonads enhances bioremediation through the propagation of bacteria with an elevated transport activity. Furthermore, strain A1 cells transformed with Zymomonas mobilis genes for pyruvate decarboxylase and alcohol dehydrogenase II produce considerable amounts of biofuel ethanol from alginate when grown statically. © 2010 Landes Bioscience

Effect of Oxygen Tension and Medium Components on Monomer Distribution of Alginate.

PubMed

Kıvılcımdan Moral, Çiğdem; Doğan, Özdemir; Sanin, Faika Dilek

2015-06-01

Alginate is a natural biopolymer composed of mannuronic and guluronic acid monomers. It is produced by algae and some species of Azotobacter and Pseudomonas. This study aims to investigate the effect of dissolved oxygen tension (DOT) and growth medium substrate and calcium concentrations on the monomeric composition of alginate produced by Azotobacter vinelandii ATCC® 9046 in a fermenter. Results showed that alginate production increased with increasing DOT from 1 to 5 %. The highest alginate production was obtained as 4.51 g/L under 20 g/L of sucrose and 50 mg/L of calcium at 5 % DOT. At these conditions, alginate was rich in mannuronic acid (up to 61 %) and it was particularly high at low calcium concentration. On the other hand, at extreme conditions such as high DOT level (10 % DOT) and low sucrose concentration (10 g/L), guluronic acid was dominant (ranging between 65 and 100 %).

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

PubMed

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

2016-06-03

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

Equalizer technology--Equal rights for disparate beads.

PubMed

Keidel, Eva-Maria; Ribitsch, Doris; Lottspeich, Friedrich

2010-06-01

One major limitation in proteomics is the detection and analysis of low-abundant proteins, i.e. in plasma. Several years ago, a technique to selectively enrich the relative concentration of low-abundant proteins was introduced by Boschetti and co-workers. It is based on a specific and saturable interaction of proteins to a high diversity of binding sites, realized by a hexapeptide library coupled to beads. This technology was commercialized as Equalizer beads or ProteoMiner. However, during application of ProteoMiner beads to plasma samples unexpected results questioned the proposed mode of action. Therefore, ProteoMiner beads were compared with chromatographic beads exhibiting completely different surface chemistry. Sepabeads FP-OD400 octadecyl, FP-DA400 diethylamine, FP-BU400 butyl, FP-HG400 hydroxyl and EXE056 epoxy were used. The results show that ProteoMiner or the different Sepabeads behave surprisingly similarly in the separation of complex protein mixtures. ProteoMiner beads interact with protein mixtures according to a general hydrophobic binding mechanism, where diversity in surface ligands plays only a negligible role.

Optical diamagnetic biosensor for immunocomplexes on beads

NASA Astrophysics Data System (ADS)

Norina, Svetlana B.

2000-12-01

In the present work, diamagnetic separation parameters for the porous beads are studied using optical video recording microscopy. The possible direct amount determination of single or double macromolecular layers immobilized in the meshes of the porous beads is demonstrated for the concentrations' range used in heterogenic immunotest and the affinity chromatography, where the direct rapid detection of ligands within sorbent particles is known to be the actual task. A gradient diamagnetic biosensor is described as suitable for rapid quantitative detection of single or double macromolecular layers in porous nonmagnetic beads. Measurements of capture traveling time or accumulation radius in gradient magnetic field have shown that it is possible to determine 0.20 mg/ml of macromolecular amount within several seconds. The portative devices were made on the base of the fabre optic technique to detect accumulation radius of collected beads in two gradient magnetic positions: diamagnetic and paramagnetic zones of magnetized wire with 55 μm in diameter and to registrate with a lot of fabre wires having 30 μm in diameters. The successive procedures of the present method can be described by: the obtaining of agarose immuno-beads, the incubation of beads with the ligand sample or the injection of sample through affinity mini-column, the submerging of the loaded beads into the glass cell containing Ni-wire or the narrow gap of magnetic poles; the computational obtaining of immuno- parameters; binding constants, accumulation radius. Several biotechnological applications of the biosensor are presented on sorbent beads, human lymphocytes.

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

PubMed

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

2016-02-29

In this work, alginate, alginate-pectin and alginate-hydroxypropylcellulose pellets were produced by ionotropic gelation and characterized. Ibuprofen was selected as model drug; it was suspended in the polymeric solution in crystalline form or dissolved in a self-emulsifying phase and then dispersed into the polymeric solution. The self-emulsifying excipient platform composed of Labrasol (PEG-8 caprylic/capric glycerides) and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS), able to solubilize the drug was used to improve the technological and biopharmaceutical properties of the alginate pellets. The pellets had diameters between 1317 and 2026 μm and a high drug content (>51%). DSC analysis showed the amorphous state of drug in the pellets containing the self-emulsifying phase. All the systems restricted drug release in conditions simulating the gastric environment and made the drug completely available at a pH value typical for the intestine. Only alginate-HPC systems containing the drug solubilized into the self-emulsifying phase showed the ability to partially control the release of ibuprofen at neutral pH. The self-emulsifying excipient platform is a useful tool to improve technological and biopharmaceutical properties of alginate-HPC pellets. Copyright © 2015 Elsevier B.V. All rights reserved.

MHD Flow of Sodium Alginate-Based Casson Type Nanofluid Passing Through A Porous Medium With Newtonian Heating.

PubMed

Khan, Arshad; Khan, Dolat; Khan, Ilyas; Ali, Farhad; Karim, Faizan Ul; Imran, Muhammad

2018-06-05

Casson nanofluid, unsteady flow over an isothermal vertical plate with Newtonian heating (NH) is investigated. Sodium alginate (base fluid)is taken as counter example of Casson fluid. MHD and porosity effects are considered. Effects of thermal radiation along with heat generation are examined. Sodium alginate with Silver, Titanium oxide, Copper and Aluminum oxide are added as nano particles. Initial value problem with physical boundary condition is solved by using Laplace transform method. Exact results are obtained for temperature and velocity fields. Skin-friction and Nusselt number are calculated. The obtained results are analyzed graphically for emerging flow parameters and discussed. It is bring into being that temperature and velocity profile are decreasing with increasing nano particles volume fraction.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

PubMed

Tytgat, G N; Simoneau, G

2006-03-15

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

Automated electrotransformation of Escherichia coli on a digital microfluidic platform using bioactivated magnetic beads.

PubMed

Moore, J A; Nemat-Gorgani, M; Madison, A C; Sandahl, M A; Punnamaraju, S; Eckhardt, A E; Pollack, M G; Vigneault, F; Church, G M; Fair, R B; Horowitz, M A; Griffin, P B

2017-01-01

This paper reports on the use of a digital microfluidic platform to perform multiplex automated genetic engineering (MAGE) cycles on droplets containing Escherichia coli cells. Bioactivated magnetic beads were employed for cell binding, washing, and media exchange in the preparation of electrocompetent cells in the electrowetting-on-dieletric (EWoD) platform. On-cartridge electroporation was used to deliver oligonucleotides into the cells. In addition to the optimization of a magnetic bead-based benchtop protocol for generating and transforming electrocompetent E. coli cells, we report on the implementation of this protocol in a fully automated digital microfluidic platform. Bead-based media exchange and electroporation pulse conditions were optimized on benchtop for transformation frequency to provide initial parameters for microfluidic device trials. Benchtop experiments comparing electrotransformation of free and bead-bound cells are presented. Our results suggest that dielectric shielding intrinsic to bead-bound cells significantly reduces electroporation field exposure efficiency. However, high transformation frequency can be maintained in the presence of magnetic beads through the application of more intense electroporation pulses. As a proof of concept, MAGE cycles were successfully performed on a commercial EWoD cartridge using variations of the optimal magnetic bead-based preparation procedure and pulse conditions determined by the benchtop results. Transformation frequencies up to 22% were achieved on benchtop; this frequency was matched within 1% (21%) by MAGE cycles on the microfluidic device. However, typical frequencies on the device remain lower, averaging 9% with a standard deviation of 9%. The presented results demonstrate the potential of digital microfluidics to perform complex and automated genetic engineering protocols.

Automated electrotransformation of Escherichia coli on a digital microfluidic platform using bioactivated magnetic beads

PubMed Central

Moore, J. A.; Nemat-Gorgani, M.; Madison, A. C.; Punnamaraju, S.; Eckhardt, A. E.; Pollack, M. G.; Church, G. M.; Fair, R. B.; Horowitz, M. A.; Griffin, P. B.

2017-01-01

This paper reports on the use of a digital microfluidic platform to perform multiplex automated genetic engineering (MAGE) cycles on droplets containing Escherichia coli cells. Bioactivated magnetic beads were employed for cell binding, washing, and media exchange in the preparation of electrocompetent cells in the electrowetting-on-dieletric (EWoD) platform. On-cartridge electroporation was used to deliver oligonucleotides into the cells. In addition to the optimization of a magnetic bead-based benchtop protocol for generating and transforming electrocompetent E. coli cells, we report on the implementation of this protocol in a fully automated digital microfluidic platform. Bead-based media exchange and electroporation pulse conditions were optimized on benchtop for transformation frequency to provide initial parameters for microfluidic device trials. Benchtop experiments comparing electrotransformation of free and bead-bound cells are presented. Our results suggest that dielectric shielding intrinsic to bead-bound cells significantly reduces electroporation field exposure efficiency. However, high transformation frequency can be maintained in the presence of magnetic beads through the application of more intense electroporation pulses. As a proof of concept, MAGE cycles were successfully performed on a commercial EWoD cartridge using variations of the optimal magnetic bead-based preparation procedure and pulse conditions determined by the benchtop results. Transformation frequencies up to 22% were achieved on benchtop; this frequency was matched within 1% (21%) by MAGE cycles on the microfluidic device. However, typical frequencies on the device remain lower, averaging 9% with a standard deviation of 9%. The presented results demonstrate the potential of digital microfluidics to perform complex and automated genetic engineering protocols. PMID:28191268

Energy efficient bead milling of microalgae: Effect of bead size on disintegration and release of proteins and carbohydrates.

PubMed

Postma, P R; Suarez-Garcia, E; Safi, C; Yonathan, K; Olivieri, G; Barbosa, M J; Wijffels, R H; Eppink, M H M

2017-01-01

The disintegration of three industry relevant algae (Chlorella vulgaris, Neochloris oleoabundans and Tetraselmis suecica) was studied in a lab scale bead mill at different bead sizes (0.3-1mm). Cell disintegration, proteins and carbohydrates released into the water phase followed a first order kinetics. The process is selective towards proteins over carbohydrates during early stages of milling. In general, smaller beads led to higher kinetic rates, with a minimum specific energy consumption of ⩽0.47kWhkg DW -1 for 0.3mm beads. After analysis of the stress parameters (stress number and stress intensity), it appears that optimal disintegration and energy usage for all strains occurs in the 0.3-0.4mm range. During the course of bead milling, the native structure of the marker protein Rubisco was retained, confirming the mildness of the disruption process. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The relationship between digital model accuracy and time-dependent deformation of alginate impressions.

PubMed

Alcan, Toros; Ceylanoğlu, Cenk; Baysal, Bekir

2009-01-01

To investigate the effects of different storage periods of alginate impressions on digital model accuracy. A total of 105 impressions were taken from a master model with three different brands of alginates and were poured into stone models in five different storage periods. In all, 21 stone models were poured and immediately were scanned, and 21 digital models were prepared. The remaining 84 impressions were poured after 1, 2, 3, and 4 days, respectively. Five linear measurements were made by three researchers on the master model, the stone models, and the digital models. Time-dependent deformation of alginate impressions at different storage periods and the accuracy of traditional stone models and digital models were evaluated separately. Both the stone models and the digital models were highly correlated with the master model. Significant deformities in the alginate impressions were noted at different storage periods of 1 to 4 days. Alginate impressions of different brands also showed significant differences between each other on the first, third, and fourth days. Digital orthodontic models are as reliable as traditional stone models and probably will become the standard for orthodontic clinical use. Storing alginate impressions in sealed plastic bags for up to 4 days caused statistically significant deformation of alginate impressions, but the magnitude of these deformations did not appear to be clinically relevant and had no adverse effect on digital modeling.

Antimicrobial cerium ion-chitosan crosslinked alginate biopolymer films: A novel and potential wound dressing.

PubMed

Kaygusuz, Hakan; Torlak, Emrah; Akın-Evingür, Gülşen; Özen, İlhan; von Klitzing, Regine; Erim, F Bedia

2017-12-01

Wound dressings require good antiseptic properties, mechanical strength and, more trustably, natural material ingredients. Antimicrobial properties of cerium ions and chitosan are known and alginate based wound dressings are commercially available. In this study, the advantages of these materials were combined and alginate films were crosslinked with cerium(III) solution and chitosan added cerium(III) solution. Films were characterized by Fourier transform infrared spectroscopy (FTIR), light transmittance, scanning electron microscopy (SEM), swelling experiments, water vapor transmittance tests, and mechanical stretching tests. The antibacterial and physical properties of the films were compared with those of conventional calcium alginate films. Both cerium ion crosslinked and cerium ion-chitosan crosslinked alginate films gained antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Cerium alginate-chitosan films showed high resistance to being deformed elastically. Results show that cerium alginate-chitosan films can be flexible, ultraviolet-protecting, and antibacterial wound dressings. Copyright © 2017 Elsevier B.V. All rights reserved.

Applications of alginate in bioseparation of proteins.

PubMed

Jain, Sulakshana; Mondal, Kalyani; Gupta, Munishwar N

2006-01-01

Alginate is a polysaccharide that is a block polymer consisting of block units of guluronic acid and mannuronic acid. It shows inherent biological affinity for a variety of enzymes such as pectinase, lipase, phospholipase D, a and ss amylases and glucoamylase. Taking advantage of its precipitation with Ca2+ and the above-mentioned property, alginate has been used for purification of these enzymes by affinity precipitation, aqueous two phase separation, macroaffinity ligand facilitated three phase partitioning, immobilized metal affinity chromatography and expanded bed affinity chromatography. Thus, this versatile marine resource has tremendous potential in bioseparation of proteins.

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.

Removal of polycyclic aromatic hydrocarbons from soil using a composite material containing iron and activated carbon in the freeze-dried calcium alginate matrix: Novel soil cleanup technique.

PubMed

Funada, Mako; Nakano, Takeshi; Moriwaki, Hiroshi

2018-06-05

A novel clean-up technology to remove polycyclic aromatic hydrocarbons (PAHs) from solid samples by magnetic separation using a composite containing iron powder as a magnetic material and activated carbon as an adsorbent in the freeze-dried calcium alginate matrix (Fe-AC-alg) has been developed. The Fe-AC-alg powder (50 mg), mixed with 1.0 g of glass beads having 12 kinds of adsorbed PAHs, was shaken without adding solvents at 300 rpm. After shaking, the Fe-AC-alg powder was separated using a permanent magnet. The quantity of the PAHs extracted from the glass beads treated by this method was determined. The removal (%) of the PAHs was over 96%. A roadside soil sample (10 g) was mixed with the Fe-AC-alg (1.0 g) for 2 weeks. The removal (%) of benzo[a]pyrene from the sample by the presented technique was 78%. The toxic equivalent concentration (Σ BaP eq ) for the sample decreased from 0.27 to 0.10 mg kg -1 by this method. The presented method is very simple, economical, and environment-friendly. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PubMed

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

2012-11-06

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

Investigation of cell viability and morphology in 3D bio-printed alginate constructs with tunable stiffness.

PubMed

Shi, Pujiang; Laude, Augustinus; Yeong, Wai Yee

2017-04-01

In this article, mouse fibroblast cells (L929) were seeded on 2%, 5%, and 10% alginate hydrogels, and they were also bio-printed with 2%, 5%, and 10% alginate solutions individually to form constructs. The elastic and viscous moduli of alginate solutions, their interior structure and stiffness, interactions of cells and alginate, cell viability, migration and morphology were investigated by rheometer, MTT assay, scanning electron microscope (SEM), and fluorescent microscopy. The three types of bio-printed scaffolds of distinctive stiffness were prepared, and the seeded cells showed robust viability either on the alginate hydrogel surfaces or in the 3D bio-printed constructs. Majority of the proliferated cells in the 3D bio-printed constructs weakly attached to the surrounding alginate matrix. The concentration of alginate solution and hydrogel stiffness influenced cell migration and morphology, moreover the cells formed spheroids in the bio-printed 10% alginate hydrogel construct. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1009-1018, 2017. © 2017 Wiley Periodicals, Inc.

Measurements of the Rotation of the Flagellar Motor by Bead Assay.

PubMed

Kasai, Taishi; Sowa, Yoshiyuki

2017-01-01

The bacterial flagellar motor is a reversible rotary nano-machine powered by the ion flux across the cytoplasmic membrane. Each motor rotates a long helical filament that extends from the cell body at several hundreds revolutions per second. The output of the motor is characterized by its generated torque and rotational speed. The torque can be calculated as the rotational frictional drag coefficient multiplied by the angular velocity. Varieties of methods, including a bead assay, have been developed to measure the flagellar rotation rate under various load conditions on the motor. In this chapter, we describe a method to monitor the motor rotation through a position of a 1 μm bead attached to a truncated flagellar filament.