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...

An acid/alkaline stress and the addition of amino acids induce a prolonged viability of Lactobacillus plantarum loaded into alginate gel.

PubMed

Bevilacqua, Antonio; Sinigaglia, Milena; Corbo, Maria Rosaria

2010-08-15

This study reports on the investigation on the effects of the conditions used throughout the step of biomass production on the survival of Lactobacillus plantarum loaded into alginate gels. L. plantarum was grown under different conditions (MRS or a laboratory medium-LB(2)-at acidic or alkaline pHs, with NaCl, phenols, vitamins or amino acids) and immobilized in sodium alginate; cell number was evaluated throughout the storage and death (delta(stand)) and first-reduction times (delta) were calculated. The storage of alginate gels at 4 degrees C prolonged cell viability up to 60 days (ca. 20 days for cells produced in MRS and stored at 30 degrees C); however, a similar prolongation was achieved for cells produced in LB(2) adjusted to pH 5.0 and 9.0 or added with amino acids (death time>50-60 days). Copyright 2010 Elsevier B.V. All rights reserved.

Microwave-induced facile synthesis of water-soluble fluorogenic alginic acid derivatives.

PubMed

Chhatbar, Mahesh U; Meena, Ramavatar; Prasad, Kamalesh; Chejara, Dharmesh R; Siddhanta, A K

2011-04-01

A facile microwave-induced method was developed for synthesizing water-soluble fluorescent derivatives of alginic acid (ALG) with four different diamines, hydrazine (HY), ethylenediamine (EDA), 1,6-hexanediamine (HDA), and 1,4-cyclohexanediamine (CHDA), followed by a cross-linking reaction with a natural cross linker genipin. The ethylenediamine derivative of alginic acid (ALG-EDA) exhibited good fluorescent activity, which upon cross linking was enhanced threefold. The other amide derivatives, for example, ALG-HY, ALG-HDA, and ALG-CHDA, were not fluorescent, but their respective crosslinked products exhibited excellent fluorescent activity. The fluorescence intensity had an inverse correlation with the number of carbon atoms present in the amine, which in turn was a function of degree of substitution (DS). These fluorescent polysaccharide derivatives are of potential utility in the domain of sensor applications. Copyright © 2011 Elsevier Ltd. 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...

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

PubMed

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

2015-07-15

Acid mine drainage sludge (AMDS) is a solid waste generated following the neutralization of acid mine drainage (AMD). This material entrapped in calcium alginate was investigated for the sorption of As(III) and As(V). Three different adsorbent materials were prepared: AMDS alginate beads (AABs), goethite alginate beads (GABs), and pure alginate beads. The effects of pH and the adsorption kinetics were investigated, and the adsorption isotherms were also evaluated. The optimum pH range using the AABs was determined to be within 2-10 for As(III) and 2-9 for As(V). Adsorption equilibrium data were evaluated using the Langmuir isotherm model, and the maximum adsorption capacity qmax was 18.25 and 4.97 mg g(-1) for As(III) on AAB and GAB, respectively, and 21.79 and 10.92 mg g(-1) for As(V) on AAB and GAB, respectively. The adsorption of As(III) and As(V) was observed to follow pseudo-second order kinetics. The As K-edge X-ray absorption near-edge structure (XANES) revealed that the adsorbed As(III) on the AABs was oxidized to As(V) via manganese oxide in the AMDS. Copyright © 2015 Elsevier B.V. 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.

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...

Еvaluation of biocompatibility and antioxidant efficiency of chitosan-alginate nanoparticles loaded with quercetin.

PubMed

Aluani, Denitsa; Tzankova, Virginia; Kondeva-Burdina, Magdalena; Yordanov, Yordan; Nikolova, Elena; Odzhakov, Feodor; Apostolov, Alexandar; Markova, Tzvetanka; Yoncheva, Krassimira

2017-10-01

The present study deals with development and evaluation of the safety profile of chitosan/alginate nanoparticles as a platform for delivery of a natural antioxidant quercetin. The nanoparticles were prepared by varying the ratios between both biopolymers giving different size and charge of the formulations. The biocompatibility was explored in vitro in cells from different origin: cultivated HepG2 cells, isolated primary rat hepatocytes, isolated murine spleen lymphocytes and macrophages. In vivo toxicological evaluation was performed after repeated 14-day oral administration to rats. The study revealed that chitosan/alginate nanoparticles did not change body weight, the relative weight of rat livers, liver histology, hematology and biochemical parameters. The protective effects of quercetin-loaded nanoparticles were investigated in the models of iron/ascorbic acid (Fe 2+ /AA) induced lipid peroxidation in microsomes and tert-butyl hydroperoxide oxidative stress in isolated rat hepatocytes. Interesting finding was that the empty chitosan/alginate nanoparticles possessed protective activity themselves. The antioxidant effects of quercetin loaded into the nanoparticles formulated with higher concentration of chitosan were superior compared to quercetin encapsulated in nanoparticles with higher amount of sodium alginate. In conclusion, chitosan/alginate nanoparticles can be considered appropriate carrier for quercetin, combining safety profile and improved protective activity of the encapsulated antioxidant. Copyright © 2017 Elsevier B.V. All rights reserved.

Forward osmosis filtration for removal of organic foulants: Effects of combined tannic and alginic acids.

PubMed

Wang, Lin; Zhang, Wanzhu; Chu, Huaqiang; Dong, Bingzhi

2016-03-15

The filtration performance of combined organic foulants by forward osmosis (FO) in active-layer-facing-the-draw-solution (AL-facing-DS) orientation was investigated systematically. Tannic acid and alginate were used as model organic foulants for polysaccharides and humic dissolved organic matters, respectively. The FO could reject combined and single tannic acid and alginate foulants effectively. The more severe fouling flux decline, accompanied with lower combined foulants' retention, was observed with increasing proportions of tannic acid in the combined foulants-containing feed, which was ascribed mainly to the more severe fouling resulting from tannic acid adsorption within the porous support layer of the FO membrane compared to minor alginate deposition on the membrane surface. It was found that the higher the initial flux level and cross flow velocity, the faster the flux decline with lower mixed foulants retention. It was also revealed that the calcium ions in a basic solution enhanced the combined fouling flux reduction and combined foulants retention. As the major constituent of the combined fouling layer, the adsorption of tannic acid might play a more significant role in the mixed fouling of the FO membrane, which was probably influenced by permeation drag caused by water flux and chemical interactions induced by feed solution pH and calcium ion concentration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure of a Bacterial ABC Transporter Involved in the Import of an Acidic Polysaccharide Alginate.

PubMed

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

2015-09-01

The acidic polysaccharide alginate represents a promising marine biomass for the microbial production of biofuels, although the molecular and structural characteristics of alginate transporters remain to be clarified. In Sphingomonas sp. A1, the ATP-binding cassette transporter AlgM1M2SS is responsible for the import of alginate across the cytoplasmic membrane. Here, we present the substrate-transport characteristics and quaternary structure of AlgM1M2SS. The addition of poly- or oligoalginate enhanced the ATPase activity of reconstituted AlgM1M2SS coupled with one of the periplasmic solute-binding proteins, AlgQ1 or AlgQ2. External fluorescence-labeled oligoalginates were specifically imported into AlgM1M2SS-containing proteoliposomes in the presence of AlgQ2, ATP, and Mg(2+). The crystal structure of AlgQ2-bound AlgM1M2SS adopts an inward-facing conformation. The interaction between AlgQ2 and AlgM1M2SS induces the formation of an alginate-binding tunnel-like structure accessible to the solvent. The translocation route inside the transmembrane domains contains charged residues suitable for the import of acidic saccharides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Attachment of alginate microcapsules onto plasma-treated PDMS sheet for retrieval after transplantation.

PubMed

Shin, Soojeong; Shin, Jeong Eun; Yoo, Young Je

2013-01-01

Although transplantation of microencapsulated islets has been proposed as a therapy for the treatment of diabetes mellitus, limited retrievability of the cells has impeded its medical usage. To achieve retrieval of microencapsulated islets, capsules were attached to polydimethylsiloxane (PDMS) with a biocompatible adhesive. Because the hydrophobic nature of the PDMS surface prevents attachment, surface modification is essential. Alginate microcapsules were attached to modified PDMS sheets, and the mechanical stability of the resulting constructs was determined. Acrylic acid (AA) and acrylamide (AM) mixtures were grafted on the surfaces of PDMS sheets using a two-step oxygen plasma treatment (TSPT). TSPT-PDMS was characterized according to water contact angle and zeta-potential measurements. The contact angle was altered by changing the ratio of AM to AA to generate hydrophilic surface. Evaluation of the surface charge at pH 2, 7, and 12 confirmed the presence of polar groups on the modified surface. Microcapsules were attached to TSPT-PDMS using Histoacryl® and shown to be in a monolayered and half-exposed state. The shear stress resistance of alginate capsules attached to the PDMS sheet indicates the possibility of transplantation of encapsulated cells without scattering in vivo. This method is applicable to retrieve microencapsulated porcine islets when required. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

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.

Alginate antacid (Gaviscon DA) chewable tablets reduce esophageal acid exposure in Chinese patients with gastroesophageal reflux disease and heartburn symptoms.

PubMed

Yuan, Yao Zong; Fang, Jing Yuan; Zou, Duo Wu; Levinson, Nigel; Jenner, Bartosz; Wilkinson, Joanne

2016-11-01

To assess the efficacy of Gaviscon Double Action (DA) alginate antacid chewable tablets for reducing esophageal acid exposure in Chinese patients with gastroesophageal reflux disease (GERD). Altogether 44 patients reporting moderate to severe heartburn symptoms underwent two pH monitoring visits. The treatment sequence was randomized to patients received DA alginate antacid or placebo at one visit and the alternate treatment 7 days later. After a standardized reflux-provoking meal, patients took four tablets of DA alginate antacid or placebo. Esophageal pH was measured for 4 h post-dosing using an electrode positioned 5 cm above the lower esophageal sphincter. The primary end-point was the percentage of 4-h post-dosing period with pH <4. Secondary end-points were number of acid reflux episodes (pH <4), longest reflux time and DeMeester scores. All 44 patients completed the study and provided data for analysis. With DA alginate antacid, the mean percentage time with pH <4 was 5.1%, significantly less (P = 0.0003) than with placebo (14.8%). DA alginate antacid was statistically significantly superior (P = 0.0290) to placebo (from at least twofold to threefold better) for all other end-points. Two patients reported two mild adverse events (AEs) that resolved within a month of completing the study. No patients had serious and/or severe AEs and none withdrew due to AEs. DA alginate antacid was statistically significantly superior to placebo in reducing post-prandial acid exposure without serious clinically relevant health risks. These findings suggest DA alginate antacid tablets are appropriate for treating acid reflux in Chinese GERD patients with heartburn symptoms. © 2016 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Interaction of fullerene (C60) nanoparticles with humic acid and alginate coated silica surfaces: measurements, mechanisms, and environmental implications.

PubMed

Chen, Kai Loon; Elimelech, Menachem

2008-10-15

The deposition kinetics of fullerene (C60) nanoparticles onto bare silica surfaces and surfaces precoated with humic acid and alginate are investigated over a range of monovalent (NaCI) and divalent (CaCl2) salt concentrations using a quartz crystal microbalance. Because simultaneous aggregation of the fullerene nanoparticles occurs, especially at higher electrolyte concentrations, we normalize the observed deposition rates by the corresponding favorable (transport-limited) deposition rates to obtain the attachment efficiencies, alpha. The deposition kinetics of fullerene nanoparticles onto bare silica surfaces are shown to be controlled by electrostatic interactions and van der Waals attraction, consistent with the classical particle deposition behavior where both favorable and unfavorable deposition regimes are observed. The presence of dissolved humic acid and alginate in solution leads to significantly slower deposition kinetics due to steric repulsion. Precoating the silica surfaces with humic acid and alginate exerts similar steric stabilization in the presence of NaCl. In the presence of CaCl2, the deposition kinetics of fullerene nanoparticles onto both humic acid- and alginate-coated surfaces are relatively high, even at relatively low (0.3 mM) calcium concentration. This behavior is attributed to the macromolecules undergoing complex formation with calcium ions, which reduces the charge and steric influences of the adsorbed macromolecular layers.

The influence of polymeric component of bioactive glass-based nanocomposite paste on its rheological behaviors and in vitro responses: hyaluronic acid versus sodium alginate.

PubMed

Sohrabi, Mehri; Hesaraki, Saeed; Kazemzadeh, Asghar

2014-04-01

Different biocomposite pastes were prepared from a solid phase that was nanoparticles of sol-gel-derived bioactive glass and different liquid phases including 3% hyaluronic acid solution, sodium alginate solutions (3% and 10 %) or mixtures of hyaluronic acid and sodium alginate (3% or 10 %) solutions in 50:50 volume ratio. Rheological properties of the pastes were measured in both rotatory and oscillatory modes. The washout behavior and in vitro apatite formation of the pastes were determined by soaking them in simulated body fluid under dynamic situation for 14 days. The proliferation and alkaline phosphatase activity of MG-63 osteoblastic cells were also determined using extracts of the pastes. All pastes could be easily injected from the standard syringes with different tip diameters. All pastes exhibited visco-elastic character, but a nonthixotropic paste was obtained using hyaluronic acid in which the loss modulus was higher than the storage modulus. The thixotropy and storage modulus were increasingly improved by adding/using sodium alginate as mixing liquid. Moreover, the pastes in which the liquid phase was sodium alginate or mixture of hyaluronic acid and 10% sodium alginate solution revealed better apatite formation ability and washout resistance than that made of hyaluronic acid alone. No cytotoxicity effects were observed by extracts of the pastes on osteoblasts but better alkaline phosphatase activity was found for the pastes containing hyaluronic acid. Overall, injectable biocomposites can be produced by mixing bioactive glass nanoparticles and sodium alginate/hyaluronic acid polymers. They are potentially useful for hard and even soft tissues treatments. Copyright © 2013 Wiley Periodicals, Inc.

An alginate-antacid formulation (Gaviscon Double Action Liquid) can eliminate or displace the postprandial 'acid pocket' in symptomatic GERD patients.

PubMed

Kwiatek, M A; Roman, S; Fareeduddin, A; Pandolfino, J E; Kahrilas, P J

2011-07-01

Recently, an 'acid pocket' has been described in the proximal stomach, particularly evident postprandially in GERD patients, when heartburn is common. By creating a low density gel 'raft' that floats on top of gastric contents, alginate-antacid formulations may neutralise the 'acid pocket'. To assess the ability of a commercial high-concentration alginate-antacid formulation to neutralize and/or displace the acid pocket in GERD patients. The 'acid pocket' was studied in ten symptomatic GERD patients. Measurements were made using concurrent stepwise pH pull-throughs, high resolution manometry and fluoroscopy in a semi-recumbent posture. Each subject was studied in three conditions: fasted, 20 min after consuming a high-fat meal and 20 min later after a 20 mL oral dose of an alginate-antacid formulation (Gaviscon Double Action Liquid, Reckitt Benckiser Healthcare, Hull, UK). The relative position of pH transition points (pH >4) to the EGJ high-pressure zone was analysed. Most patients (8/10) exhibited an acidified segment extending from the proximal stomach into the EGJ when fasted that persisted postprandially. Gaviscon neutralised the acidified segment in six of the eight subjects shifting the pH transition point significantly away from the EGJ. The length and pressure of the EGJ high-pressure zone were minimally affected. Gaviscon can eliminate or displace the 'acid pocket' in GERD patients. Considering that EGJ length was unchanged throughout, this effect was likely attributable to the alginate 'raft' displacing gastric contents away from the EGJ. These findings suggest the alginate-antacid formulation to be an appropriately targeted postprandial GERD therapy. © 2011 Blackwell Publishing Ltd.

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.

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.

Clinical implications of eicosapentaenoic acid/arachidonic acid ratio (EPA/AA) in adult patients with congenital heart disease.

PubMed

Kanoh, Miki; Inai, Kei; Shinohara, Tokuko; Tomimatsu, Hirofumi; Nakanishi, Toshio

2017-12-01

Recent studies showed that a low ratio between the levels of eicosapentaenoic acid and those of arachidonic acid (EPA/AA) is associated with higher incidence of coronary artery disease and poor prognosis of heart failure, arrhythmia, and cardiac sudden death. However, the clinical implications of EPA/AA in adult patients with congenital heart disease remain unclear. We aimed to assess the prognostic value of EPA/AA regarding cardiac events in adult patients with congenital heart disease. We measured the serum levels of eicosapentaenoic acid and arachidonic acid in 130 adult patients (median age, 31 years) stratified into two groups according to their EPA/AA (low, ≤0.22; high, >0.22). We prospectively analyzed the association between EPA/AA and incidence of cardiac events during a mean observation period of 15 months, expressed in terms of hazard ratio (HR) with 95% confidence interval (95% CI). In the subgroup of patients with biventricular circulation (2VC) (n = 76), we analyzed the same clinical endpoints. In our study population, EPA/AA was not associated with the incidence of arrhythmic events (HR, 1.52; 95% CI, 0.82-2.85; p = 0.19), but low EPA/AA was a predictor of heart failure hospitalization (HR, 2.83; 95% CI, 1.35-6.30; p < 0.01). Among patients with 2VC, an EPA/AA of ≤0.25 was associated with a significantly higher risk of arrhythmic events (HR, 2.55; 95% CI, 1.11-6.41; p = 0.03) and heart failure hospitalization (HR, 5.20; 95% CI, 1.78-18.1; p < 0.01). EPA/AA represents a useful predictor of cardiac events in adult patients with congenital heart disease.

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

Colon-specific delivery of 5-aminosalicylic acid from chitosan-Ca-alginate microparticles.

PubMed

Mladenovska, K; Raicki, R S; Janevik, E I; Ristoski, T; Pavlova, M J; Kavrakovski, Z; Dodov, M G; Goracinova, K

2007-09-05

Chitosan-Ca-alginate microparticles for colon-specific delivery and controlled release of 5-aminosalicylic acid after peroral administration were prepared using spray drying method followed by ionotropic gelation/polyelectrolyte complexation. Physicochemical characterization pointed to the negatively charged particles with spherical morphology having a mean diameter less than 9 microm. Chitosan was localized dominantly in the particle wall, while for alginate, a homogeneous distribution throughout the particles was observed. (1)H NMR, FTIR, X-ray and DSC studies indicated molecularly dispersed drug within the particles with preserved stability during microencapsulation and in simulated in vivo drug release conditions. In vitro drug release studies carried out in simulated in vivo conditions in respect to pH, enzymatic and salt content confirmed the potential of the particles to release the drug in a controlled manner. The diffusional exponents according to the general exponential release equation indicated anomalous (non-Fickian) transport in 5-ASA release controlled by a polymer relaxation, erosion and degradation. Biodistribution studies of [(131)I]-5-ASA loaded chitosan-Ca-alginate microparticles, carried out within 2 days after peroral administration to Wistar male rats in which TNBS colitis was induced, confirmed the dominant localization of 5-ASA in the colon with low systemic bioavailability.

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.

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.

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.

TiO2 nanoparticles aggregation and disaggregation in presence of alginate and Suwannee River humic acids. pH and concentration effects on nanoparticle stability.

PubMed

Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

2013-10-15

The behavior of manufactured TiO2 nanoparticles is studied in a systematic way in presence of alginate and Suwannee River humic acids at variable concentrations. TiO2 nanoparticles aggregation, disaggregation and stabilization are investigated using dynamic light scattering and electrophoretic experiments allowing the measurement of z-average hydrodynamic diameters and zeta potential values. Stability of the TiO2 nanoparticles is discussed by considering three pH-dependent electrostatic scenarios. In the first scenario, when pH is below the TiO2 nanoparticle point of zero charge, nanoparticles exhibit a positively charged surface whereas alginate and Suwannee River humic acids are negatively charged. Fast adsorption at the TiO2 nanoparticles occurs, promotes surface charge neutralization and aggregation. By increasing further alginate and Suwannee River humic acids concentrations charge inversion and stabilization of TiO2 nanoparticles are obtained. In the second electrostatic scenario, at the surface charge neutralization pH, TiO2 nanoparticles are rapidly forming aggregates. Adsorption of alginate and Suwannee River humic acids on aggregates leads to their partial fragmentation. In the third electrostatic scenario, when nanoparticles, alginate and Suwannee River humic acids are negatively charged, only a small amount of Suwannee River humic acids is adsorbed on TiO2 nanoparticles surface. It is found that the fate and behavior of individual and aggregated TiO2 nanoparticles in presence of environmental compounds are mainly driven by the complex interplay between electrostatic attractive and repulsive interactions, steric and van der Waals interactions, as well as concentration ratio. Results also suggest that environmental aquatic concentration ranges of humic acids and biopolymers largely modify the stability of aggregated or dispersed TiO2 nanoparticles. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Risk control of traditional Chinese medicines containing aristolochis acids (AAs) based on influencing factors of content of AAs].

PubMed

Tian, Jing-Zhuo; Liang, Ai-Hua; Liu, Jing; Zhang, Bo-Li

2017-12-01

Aristolochic acids (AAs) widely exist in such plants as Aristolochia and Asarum. The renal toxicity of AAs as well as its carcinogenicity to urinary system have been widely known. In 2003 and 2004, China prohibited the use of Aristolochiae Radix, Aristolochiae Manshuriensis Caulis and Aristolochiae Fangchi Radix, and required administering other AAs-containing medicines in accordance with the regulations for prescription drugs. In this paper, we retrieved literatures on the content determination of AAs in recent 10 years in China. It suggested that the AAs content is lower in Asarum herb, especially in its roots and rhizomes, and most of which do not show detectable amount of AA-I. Some of traditional Chinese medicines show fairly small amount of detectable AA-I. The AAs content in Aristolochia herb (including Fructus Aristolochiae, kaempfer dutchmanspipe root) is relatively high; however, there are fewer literatures for studying the content determination of AAs in Chinese patent medicines. There were many factors affecting AAs content, including the parts used, origins, processing methods, extraction process. It suggested that we should pay attention to the toxicity of Chinese medicines containing AAs and use these decoction pieces and traditional Chinese medicines cautiously. In addition, basic studies for the origins, processing methods and extraction process of Chinese patent medicines containing AAs, as well as supervision and detection of AAs content in traditional Chinese medicinal materials, decoction pieces and Chinese patent medicines shall be strengthened for reducing medication risk and guaranteeing clinical medication safety. Copyright© by the Chinese Pharmaceutical Association.

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'.

Synthesis, characterization and cytotoxicity of S-nitroso-mercaptosuccinic acid-containing alginate/chitosan nanoparticles

NASA Astrophysics Data System (ADS)

Seabra, Amedea B.; Fabbri, Giulia K.; Pelegrino, Milena T.; Silva, Letícia C.; Rodrigues, Tiago

2017-06-01

Nitric oxide (NO) is an endogenous free radical, which plays key roles in several biological processes including vasodilation, neurotransmission, inhibition of platelet adhesion, cytotoxicity against pathogens, wound healing, and defense against cancer. Due to the relative instability of NO in vivo (half-life of ca. 0.5 seconds), there is an increasing interest in the development of low molecular weight NO donors, such as S-nitrosothiols (RSNOs), which are able to prolong and preserve the biological activities of NO in vivo. In order to enhance the sustained NO release in several biomedical applications, RSNOs have been successfully allied to nanomaterials. In this context, this work describes the synthesis and characterization of the NO donor S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), which belongs to the class of RSNOs, and its incorporation in polymeric biodegradable nanoparticles composed by alginate/chitosan. First, chitosan nanoparticles were obtained by gelation process with sodium tripolyphosphate (TPP), followed by the addition of the alginate layer, to enhance the nanoparticle protection. The obtained nanoparticles presented a hydrodynamic diameter of 343 ± 38 nm, polydispersity index (PDI) of 0.36 ± 0.1, and zeta potential of - 30.3 ± 0.4 mV, indicating their thermal stability in aqueous suspension. The negative zeta potential value was assigned to the presence of alginate chains on the surface of chitosan/TPP nanoparticles. The encapsulation efficiency of the NO donor into the polymeric nanoparticles was found to be 98 ± 0.2%. The high encapsulation efficiency value was attributed to the positive interactions between the NO donor and the polymeric content of the nanoparticles. Kinetics of NO release from the nanoparticles revealed a spontaneous and sustained release of therapeutic amounts of NO, for several hours under physiological temperature. The incubation of NO-releasing alginate/chitosan nanoparticles with human hepatocellular carcinoma

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 %).

Synthesis and characterisation of multifunctional alginate microspheres via the in situ formation of ZnO quantum dots and the graft of 4-(1-pyrenyl) butyric acid to sodium alginate.

PubMed

Luo, Guilin; Wang, Jianxin; Wang, Yingying; Feng, Bo; Weng, Jie

2015-01-01

Growth factor-loaded fluorescent alginate microspheres, which can realise sustained growth factor release and fluorescence imaging, were synthesised by in situ formation of ZnO quantum dots (QDs) and covalent graft of 4-(1-pyrenyl) butyric acid (PBA). BSA was chosen as a growth factor model protein to study the release kinetic of growth factors from alginate microspheres. The microsphere size and fluorescent properties were also investigated. Investigations of cell culture were used for evaluating biocompatibility of BSA-loaded fluorescent microspheres and fluorescence imaging property of ZnO QDs and PBA-grafted sodium alginate from the microspheres. The results show that they have good fluorescent property either to microspheres or to cells and fluorescent microspheres have good biocompatibility and property in sustained release of growth factors. The obtained microspheres will be expected to realise the imaging of cells and materials and also the release of growth factor in tissue engineering or in cell culture.

Impact of feed counterion addition and cyclone type on aerodynamic behavior of alginic-atenolol microparticles produced by spray drying.

PubMed

Ceschan, Nazareth Eliana; Bucalá, Verónica; Ramírez-Rigo, María Verónica; Smyth, Hugh David Charles

2016-12-01

The inhalatory route has emerged as an interesting non-invasive alternative for drug delivery. This allows both pulmonary (local) and systemic treatments (via alveolar absorption). Further advantages in terms of stability, dose and patient preference have often lead researchers to focus on dry powder inhaler delivery systems. Atenolol is an antihypertensive drug with low oral bioavailability and gastrointestinal side effects. Because atenolol possesses adequate permeation across human epithelial membranes, it has been proposed as a good candidate for inhalatory administration. In a previous work, atenolol was combined with alginic acid (AA) and microparticles were developed using spray-drying (SD) technology. Different AA/atenolol ratios, total feed solid content and operative variables were previously explored. In order to improve particle quality for inhalatory administration and the SD yield, in this work the AA acid groups not neutralized by atenolol were kept either free or neutralized to pH∼7 and two different SD cyclones were used. Particle morphology, flow properties, moisture uptake and in vitro aerosolization behavior at different pressure drops were studied. When the AA acid groups were neutralized, particle size decreased as a consequence of the lower feed viscosity. The SD yield and in vitro particle deposition significantly increased when a high performance cyclone was employed, and even when lactose carrier particles were not used. Although the in vitro particle deposition decreased when the storage relative humidity increased, the developed SD powders showed adequate characteristics to be administered by inhalatory route up to storage relative humidities of about 60%. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced drug encapsulation and extended release profiles of calcium-alginate nanoparticles by using tannic acid as a bridging cross-linking agent.

PubMed

Abulateefeh, Samer R; Taha, Mutasem O

2015-01-01

Calcium alginate nanoparticles (NPs) suffer from sub-optimal stability in bio-relevant media leading to low drug encapsulation efficiency and uncontrolled release profiles. To sort out these drawbacks, a novel approach is proposed herein based on introducing tannic acid into these NPs to act as a bridging cross-linking aid agent. Calcium-alginate NPs were prepared by the ionotropic gelation method and loaded with diltiazem hydrochloride as a model drug. These NPs were characterized in terms of particle size, zeta potential, and morphology, and results were explained in accordance with Fourier-transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The incorporation of tannic acid led to more than four folds increase in drug encapsulation efficiency (i.e. from 15.3% to 69.5%) and reduced burst drug release from 44% to around 10% within the first 30 min. These findings suggest the possibility of improving the properties of Ca-alginate NPs by incorporating cross-linking aid agents under mild conditions.

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.

Mildly abnormal general movement quality in infants is associated with higher Mead acid and lower arachidonic acid and shows a U-shaped relation with the DHA/AA ratio.

PubMed

van Goor, S A; Schaafsma, A; Erwich, J J H M; Dijck-Brouwer, D A J; Muskiet, F A J

2010-01-01

We showed that docosahexaenoic acid (DHA) supplementation during pregnancy and lactation was associated with more mildly abnormal (MA) general movements (GMs) in the infants. Since this finding was unexpected and inter-individual DHA intakes are highly variable, we explored the relationship between GM quality and erythrocyte DHA, arachidonic acid (AA), DHA/AA and Mead acid in 57 infants of this trial. MA GMs were inversely related to AA, associated with Mead acid, and associated with DHA/AA in a U-shaped manner. These relationships may indicate dependence of newborn AA status on synthesis from linoleic acid. This becomes restricted during the intrauterine period by abundant de novo synthesis of oleic and Mead acids from glucose, consistent with reduced insulin sensitivity during the third trimester. The descending part of the U-shaped relation between MA GMs and DHA/AA probably indicates DHA shortage next to AA shortage. The ascending part may reflect a different developmental trajectory that is not necessarily unfavorable. Copyright 2009 Elsevier Ltd. All rights reserved.

[Pleural covering method of polyglycolic acid felt with sodium alginate water solution for prevention of postoperative pulmonary fistula].

PubMed

Ohta, S; Hirose, M; Ishibashi, H

2008-07-01

Sodium alginate is the main ingredient of the seaweed, and its water solution has moderate viscosity. The areas of the pleural defect and around the suture line were covered with polyglycolic acid felt by using 5% sodium alginate water solution in 41 patients who underwent pulmonary resection from November 2006 to April 2007. 28 patients were lung cancer, 6 patients were pulmonary metastasis, and 7 patients were pneumothorax. The duration of the postoperative air leakage was 0.7 days on average. Neither side effect nor complication was observed. This method is cheap, safe, and effective for prevention for postoperative pulmonary fistula.

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.

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.

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.

Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

NASA Astrophysics Data System (ADS)

Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

2015-11-01

Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

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.

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

PubMed

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

2018-01-01

Research to measure the chemical characterization of alginate rafts for good raft performance and ascertain how formulation can affect chemical parameters. A selection of alginate formulations was investigated all claiming to be proficient raft formers with significance between products established and ranked. Procedures were selected which demonstrated the chemical characterization allowing rafts to effectively impede the reflux into the esophagus or in severe cases to be refluxed preferentially into the esophagus and exert a demulcent effect, with focus of current research on methods which complement previous studies centered on physical properties. The alginate content was analyzed by a newly developed HPLC method. Methods were used to determine the neutralization profile and the acid neutralization within the raft determined along with how raft structure affects neutralization. Alginate content of Gaviscon Double Action (GDA) within the raft was significantly superior (p < .0001) to all competitor products. The two products with the highest raft acid neutralization capacity were GDA and Rennie Duo, the latter product not being a raft former. Raft structure was key and GDA had the right level of porosity to allow for longer duration of neutralization. Alginate formulations require three chemical reactions to take place simultaneously: transformation to alginic acid, sodium carbonate reacting to form carbon dioxide, calcium releasing free calcium ions to bind with alginic acid providing strength to raft formation. GDA was significantly superior (p <.0001) to all other comparators.

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

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

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.

Preparation, Characterization and Properties of Alginate/Poly(γ-glutamic acid) Composite Microparticles

PubMed Central

Tong, Zongrui; Chen, Yu; Liu, Yang; Tong, Li; Chu, Jiamian; Xiao, Kecen; Zhou, Zhiyu; Dong, Wenbo; Chu, Xingwu

2017-01-01

Alginate (Alg) is a renewable polymer with excellent hemostatic properties and biocapability and is widely used for hemostatic wound dressing. However, the swelling properties of alginate-based wound dressings need to be promoted to meet the requirements of wider application. Poly(γ-glutamic acid) (PGA) is a natural polymer with high hydrophility. In the current study, novel Alg/PGA composite microparticles with double network structure were prepared by the emulsification/internal gelation method. It was found from the structure characterization that a double network structure was formed in the composite microparticles due to the ion chelation interaction between Ca2+ and the carboxylate groups of Alg and PGA and the electrostatic interaction between the secondary amine group of PGA and the carboxylate groups of Alg and PGA. The swelling behavior of the composite microparticles was significantly improved due to the high hydrophility of PGA. Influences of the preparing conditions on the swelling behavior of the composites were investigated. The porous microparticles could be formed while compositing of PGA. Thermal stability was studied by thermogravimetric analysis method. Moreover, in vitro cytocompatibility test of microparticles exhibited good biocompatibility with L929 cells. All results indicated that such Alg/PGA composite microparticles are a promising candidate in the field of wound dressing for hemostasis or rapid removal of exudates. PMID:28398222

Preparation, Characterization and Properties of Alginate/Poly(γ-glutamic acid) Composite Microparticles.

PubMed

Tong, Zongrui; Chen, Yu; Liu, Yang; Tong, Li; Chu, Jiamian; Xiao, Kecen; Zhou, Zhiyu; Dong, Wenbo; Chu, Xingwu

2017-04-11

Alginate (Alg) is a renewable polymer with excellent hemostatic properties and biocapability and is widely used for hemostatic wound dressing. However, the swelling properties of alginate-based wound dressings need to be promoted to meet the requirements of wider application. Poly( γ -glutamic acid) (PGA) is a natural polymer with high hydrophility. In the current study, novel Alg/PGA composite microparticles with double network structure were prepared by the emulsification/internal gelation method. It was found from the structure characterization that a double network structure was formed in the composite microparticles due to the ion chelation interaction between Ca 2+ and the carboxylate groups of Alg and PGA and the electrostatic interaction between the secondary amine group of PGA and the carboxylate groups of Alg and PGA. The swelling behavior of the composite microparticles was significantly improved due to the high hydrophility of PGA. Influences of the preparing conditions on the swelling behavior of the composites were investigated. The porous microparticles could be formed while compositing of PGA. Thermal stability was studied by thermogravimetric analysis method. Moreover, in vitro cytocompatibility test of microparticles exhibited good biocompatibility with L929 cells. All results indicated that such Alg/PGA composite microparticles are a promising candidate in the field of wound dressing for hemostasis or rapid removal of exudates.

Molecular models of alginic acid: Interactions with calcium ions and calcite surfaces

NASA Astrophysics Data System (ADS)

Perry, Thomas D.; Cygan, Randall T.; Mitchell, Ralph

2006-07-01

Cation binding by polysaccharides is observed in many environments and is important for predictive environmental modeling, and numerous industrial and food technology applications. The complexities of these cation-organic interactions are well suited for predictive molecular modeling and the analysis of conformation and configuration of polysaccharides and their influence on cation binding. In this study, alginic acid was chosen as a model polymer system and representative disaccharide and polysaccharide subunits were developed. Molecular dynamics simulation of the torsion angles of the ether linkage between various monomeric subunits identified local and global energy minima for selected disaccharides. The simulations indicate stable disaccharide configurations and a common global energy minimum for all disaccharide models at Φ = 274 ± 7°, Ψ = 227 ± 5°, where Φ and Ψ are the torsion angles about the ether linkage. The ability of disaccharide subunits to bind calcium ions and to associate with the (101¯4) surface of calcite was also investigated. Molecular models of disaccharide interactions with calcite provide binding energy differences for conformations that are related to the proximity and residence densities of the electron-donating moieties with calcium ions on the calcite surface, which are controlled, in part, by the torsion of the ether linkage between monosaccharide units. Dynamically optimized configurations for polymer alginate models with calcium ions were also derived.

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.

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.

Pb(II) adsorption by a novel activated carbon - alginate composite material. A kinetic and equilibrium study.

PubMed

Cataldo, Salvatore; Gianguzza, Antonio; Milea, Demetrio; Muratore, Nicola; Pettignano, Alberto

2016-11-01

The adsorption capacity of an activated carbon - calcium alginate composite material (ACAA-Ca) has been tested with the aim of developing a new and more efficient adsorbent material to remove Pb(II) ion from aqueous solution. The study was carried out at pH=5, in NaCl medium and in the ionic strength range 0.1-0.75molL -1 . Differential Pulse Anodic Stripping Voltammetry (DP-ASV) technique was used to check the amount of Pb(II) ion removed during kinetic and equilibrium experiments. Different kinetic (pseudo first order, pseudo second order and Vermuelen) and equilibrium (Langmuir and Freundlich) models were used to fit experimental data, and were statistically compared. Calcium alginate (AA-Ca) improves the adsorption capacity (q m ) of active carbon (AC) in the ACAA-Ca adsorbent material (e.g., q m =15.7 and 10.5mgg -1 at I=0.25molL -1 , for ACAA-Ca and AC, respectively). SEM-EDX and thermogravimetric (TGA) measurements were carried out in order to characterize the composite material. The results of the speciation study on the Pb(II) solution and of the characterization of the ACAA-Ca and of the pristine AA-Ca and AC were evaluated in order to explain the specific contribution of AC and AA-Ca to the adsorption of the metal ion. Copyright © 2016 Elsevier B.V. All rights reserved.

Grafting of alginates on UF/NF ceramic membranes for wastewater treatment.

PubMed

Athanasekou, C P; Romanos, G E; Kordatos, K; Kasselouri-Rigopoulou, V; Kakizis, N K; Sapalidis, A A

2010-10-15

The mechanism of heavy metal ion removal in processes involving multi-layered tubular ultrafiltration and nanofiltration (UF/NF) membranes was investigated by conducting retention experiments in both flow-through and cross-flow modes. The prospect of the regeneration of the membranes through an acidic process was also examined and discussed. The UF/NF membranes were functionalised with alginates to develop hybrid inorganic/organic materials for continuous, single pass, wastewater treatment applications. The challenge laid in the induction of additional metal adsorption and improved regeneration capacity. This was accomplished by stabilizing alginates either into the pores or on the top-separating layer of the membrane. The preservation of efficient water fluxes at moderate trans-membrane pressures introduced an additional parameter that was pursued in parallel to the membrane modification process. The deposition and stabilization of alginates was carried out via physical (filtration/cross-linking) and chemical (grafting) procedures. The materials developed by means of the filtration process exhibited a 25-60% enhancement of their Cd(2+) binding capacity, depending on the amount of the filtered alginate solution. The grafting process led to the development of alginate layers with adequate stability under acidic regeneration conditions and metal retention enhancement of 25-180%, depending on the silane involved as grafting agent and the solvent of silanisation. 2010 Elsevier B.V. All rights reserved.

Alginate/hyaluronic acid hydrogel delivery system characteristics regulate the differentiation of periodontal ligament stem cells toward chondrogenic lineage.

PubMed

Ansari, Sahar; Diniz, Ivana M; Chen, Chider; Aghaloo, Tara; Wu, Benjamin M; Shi, Songtao; Moshaverinia, Alireza

2017-09-15

Cartilage tissue regeneration often presents a challenging clinical situation. Recently, it has been shown that Periodontal Ligament Stem Cells (PDLSCs) possess high chondrogenic differentiation capacity. In this study, we developed a stem cell delivery system based on alginate/hyaluronic acid (HA) loaded with TGF-β1 ligand, encapsulating PDLSCs; and investigated the chondrogenic differentiation of encapsulated cells in alginate/HA hydrogel microspheres in vitro and in vivo. The results showed that PDLSCs, as well as human bone marrow mesenchymal stem cells (hBMMSCs), as the positive control, were stained positive for both toluidine blue and alcian blue staining, while exhibiting high levels of gene expression related to chondrogenesis (Col II, Aggrecan and Sox-9), as assessed via qPCR. The quantitative PCR analyses exhibited that the chondrogenic differentiation of encapsulated MSCs can be regulated by the modulus of elasticity of hydrogel delivery system, confirming the vital role of the microenvironment, and the presence of inductive signals for viability and differentiation of MSCs. In vivo, histological and immunofluorescence staining for chondrogenic specific protein markers confirmed ectopic cartilage-like tissue regeneration inside transplanted hydrogels. PDLSCs presented significantly greater capability for chondrogenic differentiation than hBMMSCs (P < 0.05). Altogether, our findings confirmed that alginate/HA hydrogels encapsulating PDLSCs are a promising candidate for cartilage regeneration.

Green Synthesis of Silver Nanoparticles Using Sodium Alginate and Lignosulphonic Acid Blends

NASA Astrophysics Data System (ADS)

Thakur, Amrita; Reddy, Giridhar

2017-08-01

A simple method based on the principles of green chemistry has been developed to synthesize stable silver nanoparticles (AgNP) for possible biomedical applications. Blend of sodium alginate (SA) and lignosulphonic acid (LS) prepared in the ratio of 80/20 mass percent respectively was used as reducing and stabilizing agent. This blend is biocompatible and has shown drug release ability under physiological conditions. Use of blend has an added advantage as LS has the ability to reduce silver while the blend matrix acts as a stabilizing agent. Effect of precursor concentration (AgNO3) and temperature was investigated. Progress of synthesis was monitored using UV-Vis spectroscopy. Higher temperature and lower silver nitrate concentration showed better synthesis of AgNP.

Floating dosage forms to prolong gastro-retention--the characterisation of calcium alginate beads.

PubMed

Stops, Frances; Fell, John T; Collett, John H; Martini, Luigi G

2008-02-28

Floating calcium alginate beads, designed to improve drug bioavailability from oral preparations compared with that from many commercially available and modified release products, have been investigated as a possible gastro-retentive dosage form. A model drug, riboflavin, was also incorporated into the formula. The aims of the current work were (a) to obtain information regarding the structure, floating ability and changes that occurred when the dosage form was placed in aqueous media, (b) to investigate riboflavin release from the calcium alginate beads in physiologically relevant media prior to in vivo investigations. Physical properties of the calcium alginate beads were investigated. Using SEM and ESEM, externally the calcium alginate beads were spherical in shape, and internally, air filled cavities were present thereby enabling floatation of the beads. The calcium alginate beads remained buoyant for times in excess of 13h, and the density of the calcium alginate beads was <1.000gcm(-3). Riboflavin release from the calcium alginate beads showed that riboflavin release was slow in acidic media, whilst in more alkali media, riboflavin release was more rapid. The characterisation studies showed that the calcium alginate beads could be considered as a potential gastro-retentive dosage form.

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

AA-PMe, a novel asiatic acid derivative, induces apoptosis and suppresses proliferation, migration, and invasion of gastric cancer cells.

PubMed

Jing, Yue; Wang, Gang; Ge, Ying; Xu, Minjie; Tang, Shuainan; Gong, Zhunan

2016-01-01

Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is widely used for medicinal purposes in many Asian countries due to its various bioactivities. A series of AA derivatives has been synthesized in attempts to improve its therapeutic potencies. Herein we investigated the anti-tumor activities of N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), a novel AA derivative. AA-PMe exhibited a stronger anti-cancer activity than its parent compound AA. AA-PMe inhibited the proliferation of SGC7901 and HGC27 human gastric cancer cells in a dose-dependent manner but had no significant toxicity in human gastric mucosa epithelial cells (GES-1). AA-PMe induced cell cycle arrest in G0/G1 phase and blocked G1-S transition, which correlated well with marked decreases in levels of cyclin D1, cyclin-dependent kinase CKD4, and phosphorylated retinoblastoma protein, and increase in cyclin-dependent kinase inhibitor P15. Further, AA-PMe induced apoptosis of human gastric cancer cells by affecting Bcl-2, Bax, c-Myc, and caspase-3. Moreover, AA-PMe suppressed the migration and invasion of human gastric cancer cells (SGC7901 and HGC27) cells by downregulating the expression of MMP-2 and MMP-9. Overall, this study investigated the potential anti-cancer activities of AA-PMe including inducing apoptosis and suppressing proliferation, migration and invasion of gastric cancer cells, as well as the underlying mechanisms, suggesting that AA-PMe is a promising anti-cancer drug candidate in gastric cancer therapy.

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

AA-PMe, a novel asiatic acid derivative, induces apoptosis and suppresses proliferation, migration, and invasion of gastric cancer cells

PubMed Central

Jing, Yue; Wang, Gang; Ge, Ying; Xu, Minjie; Tang, Shuainan; Gong, Zhunan

2016-01-01

Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is widely used for medicinal purposes in many Asian countries due to its various bioactivities. A series of AA derivatives has been synthesized in attempts to improve its therapeutic potencies. Herein we investigated the anti-tumor activities of N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), a novel AA derivative. AA-PMe exhibited a stronger anti-cancer activity than its parent compound AA. AA-PMe inhibited the proliferation of SGC7901 and HGC27 human gastric cancer cells in a dose-dependent manner but had no significant toxicity in human gastric mucosa epithelial cells (GES-1). AA-PMe induced cell cycle arrest in G0/G1 phase and blocked G1-S transition, which correlated well with marked decreases in levels of cyclin D1, cyclin-dependent kinase CKD4, and phosphorylated retinoblastoma protein, and increase in cyclin-dependent kinase inhibitor P15. Further, AA-PMe induced apoptosis of human gastric cancer cells by affecting Bcl-2, Bax, c-Myc, and caspase-3. Moreover, AA-PMe suppressed the migration and invasion of human gastric cancer cells (SGC7901 and HGC27) cells by downregulating the expression of MMP-2 and MMP-9. Overall, this study investigated the potential anti-cancer activities of AA-PMe including inducing apoptosis and suppressing proliferation, migration and invasion of gastric cancer cells, as well as the underlying mechanisms, suggesting that AA-PMe is a promising anti-cancer drug candidate in gastric cancer therapy. PMID:27073325

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.

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.

Encapsulated eucalyptus oil in ionically cross-linked alginate microcapsules and its controlled release.

PubMed

Noppakundilograt, Supaporn; Piboon, Phianghathai; Graisuwan, Wilaiporn; Nuisin, Roongkan; Kiatkamjornwong, Suda

2015-10-20

Sodium alginate microcapsules containing eucalyptus oil were prepared by oil-in-water emulsification via Shirasu porous glass (SPG) membrane and cross-linked by calcium chloride (CaCl2). SPG membrane pore size of 5.2μm was used to control the size of eucalyptus oil microdroplets. Effects of sodium alginate, having a mannuronic acid/guluronic acid (M/G) ratio of 1.13, eucalyptus oil and CaCl2 amounts on microdroplet sizes and size distribution were elucidated. Increasing sodium alginate amounts from 0.1 to 0.5% (wv(-1)) sodium alginate, the average droplets size increased from 42.2±2.0 to 48.5±0.6μm, with CVs of 16.5±2.2 and 30.2±4.5%, respectively. CaCl2 successfully gave narrower size distribution of cross-linked eucalyptus oil microcapsules. The optimum conditions for preparing the microcapsules, oil loading efficiency, and controlled release of the encapsulated eucalyptus oil from the microcapsules as a function of time at 40°C were investigated. Release model for the oil from microcapsules fitted Ritger-Peppas model with non-Fickian transport mechanism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Three-dimensional prostate tumor model based on a hyaluronic acid-alginate hydrogel for evaluation of anti-cancer drug efficacy.

PubMed

Tang, Yadong; Huang, Boxin; Dong, Yuqin; Wang, Wenlong; Zheng, Xi; Zhou, Wei; Zhang, Kun; Du, Zhiyun

2017-10-01

In vitro cell-based assays are widely applied to evaluate anti-cancer drug efficacy. However, the conventional approaches are mostly based on two-dimensional (2D) culture systems, making it difficult to recapitulate the in vivo tumor scenario because of spatial limitations. Here, we develop an in vitro three-dimensional (3D) prostate tumor model based on a hyaluronic acid (HA)-alginate hybrid hydrogel to bridge the gap between in vitro and in vivo anticancer drug evaluations. In situ encapsulation of PCa cells was achieved by mixing HA and alginate aqueous solutions in the presence of cells and then crosslinking with calcium ions. Unlike in 2D culture, cells were found to aggregate into spheroids in a 3D matrix. The expression of epithelial to mesenchyme transition (EMT) biomarkers was found to be largely enhanced, indicating an increased invasion and metastasis potential in the hydrogel matrix. A significant up-regulation of proangiogenic growth factors (IL-8, VEGF) and matrix metalloproteinases (MMPs) was observed in 3D-cultured PCa cells. The results of anti-cancer drug evaluation suggested a higher drug tolerance within the 3D tumor model compared to conventional 2D-cultured cells. Finally, we found that the drug effect within the in vitro 3D cancer model based on HA-alginate matrix exhibited better predictability for in vivo drug efficacy.

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

Variation of amino acid sequences of serum amyloid a (SAA) and immunohistochemical analysis of amyloid a (AA) in Japanese domestic cats.

PubMed

Tei, Meina; Uchida, Kazuyuki; Chambers, James K; Watanabe, Ken-Ichi; Tamamoto, Takashi; Ohno, Koichi; Nakayama, Hiroyuki

2018-02-02

Amyloid A (AA) amyloidosis, a fatal systemic amyloid disease, occurs secondary to chronic inflammatory conditions in humans. Although persistently elevated serum amyloid A (SAA) levels are required for its pathogenesis, not all individuals with chronic inflammation necessarily develop AA amyloidosis. Furthermore, many diseases in cats are associated with the elevated production of SAA, whereas only a small number actually develop AA amyloidosis. We hypothesized that a genetic mutation in the SAA gene may strongly contribute to the pathogenesis of feline AA amyloidosis. In the present study, genomic DNA from four Japanese domestic cats (JDCs) with AA amyloidosis and from five without amyloidosis was analyzed using polymerase chain reaction (PCR) amplification and direct sequencing. We identified the novel variation combination of 45R-51A in the deduced amino acid sequences of four JDCs with amyloidosis and five without. However, there was no relationship between amino acid variations and the distribution of AA amyloid deposits, indicating that differences in SAA sequences do not contribute to the pathogenesis of AA amyloidosis. Immunohistochemical analysis using antisera against the three different parts of the feline SAA protein-i.e., the N-terminal, central, and C-terminal regions-revealed that feline AA contained the C-terminus, unlike human AA. These results indicate that the cleavage and degradation of the C-terminus are not essential for amyloid fibril formation in JDCs.

Eicosapentaenoic acid to arachidonic acid (EPA/AA) ratio as an associated factor of high risk plaque on coronary computed tomography in patients without coronary artery disease.

PubMed

Nagahara, Yasuomi; Motoyama, Sadako; Sarai, Masayoshi; Ito, Hajime; Kawai, Hideki; Takakuwa, Yoko; Miyagi, Meiko; Shibata, Daisuke; Takahashi, Hiroshi; Naruse, Hiroyuki; Ishii, Junichi; Ozaki, Yukio

2016-07-01

Coronary computed tomography angiography (CCTA)-verified high risk plaque (HRP) characteristics including positive remodeling and low attenuation plaque have been associated with acute coronary syndromes. Several studies reported that the n-3 polyunsaturated fatty acids have been associated with cardiovascular events. However, the relationship between serum eicosapentaenoic acid to arachidonic acid (EPA/AA) ratio and CCTA-verified HRP in patients without known coronary artery disease (CAD) is unclear. We aimed at investigating the relation between EPA/AA and CCTA-verified HRP in patients without known CAD. We included 193 patients undergoing CCTA without known CAD (65.5 ± 12.0 years, 55.0% male). No patient has been treated with EPA. The relation of coronary risk factors, lipid profile, high-sensitivity C-reactive protein, coronary artery calcification score (CACS), number of vessel disease, plaque burden, and EPA/AA with the presence of HRP was evaluated by logistic regression analysis. Incremental value of EPA/AA to predict HRP was also analyzed by C-index, NRI, and IDI. A Cox proportional hazards model was used to estimate the time to cardiovascular event. HRP was observed in 37 (19%) patients. Multivariable logistic regression analysis revealed that current smoking (OR 2.58; p=0.046), number of vessel disease (OR 1.87; p=0.031), and EPA/AA ratio (OR 0.65; p=0.0006) were independent associated factors of HRP on CCTA. Although the addition of EPA/AA to the baseline model did not significantly improve C-index, both NRI (0.60, p=0.0049) and IDI (0.054, p=0.0072) were significantly improved. Patients with HRP had significantly higher rate of events compared with patients without HRP (14% vs. 3%, Logrank p=0.0004). On multivariable Cox hazard analysis, baseline EPA/AA ratio was an independent predictor (HR 0.57, p=0.047). Low EPA/AA was an associated factor of HRP on CCTA in patients without CAD. In addition to conventional coronary risk factors and CACS, EPA/AA

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.

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

A bio-injectable algin-aminocaproic acid thixogel with tri-stimuli responsiveness.

PubMed

Chejara, Dharmesh R; Mabrouk, Mostafa; Badhe, Ravindra V; Mulla, Jameel A S; Kumar, Pradeep; Choonara, Yahya E; du Toit, Lisa C; Pillay, Viness

2016-01-01

In this article a novel bio-injectable algin-aminocaproic acid (Alg-ACA) tri-stimuli responsive thixogel system is reported. The designed soft thixotrophic hydrogel (thixogel) was characterized using various analytical techniques such as FT-IR, NMR, SEM, AFM and DSC. The soft thixogel system was further investigated for stress responsiveness using different rheological studies which confirmed the thixotropic nature of the gel [Thixotropic area (Ar) of Alg-ACA (1:0.5), Alg-ACA (1:1) and Alg-ACA (1:2), were 23.5%, 43.1%, and 27.59%, respectively, which were higher than that of Na-Alg (2.08%)]. The thixogel also demonstrated temperature and ultrasonication responsiveness. This tri-stimuli responsive soft thixogel system was rendered flowable (fluid) on applying the described physical stimuli and recovered its "rigid" gel structure upon removal of the applied stimuli. This approach of synthesizing a thixogels may be applicable to a broad variety of other natural polymers and has the potential for use in biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Purification and characterization of an alginate lyase from marine Bacterium Vibrio sp. mutant strain 510-64.

PubMed

Hu, Xiaoke; Jiang, Xiaolu; Hwang, Huey-Min

2006-08-01

Marine Vibrio sp. 510 was chosen as a parent strain for screening high producers of alginate lyase using the complex mutagenesis of Ethyl Methanesulphonate and UV radiation treatments. The mutant strain Vibrio sp. 510-64 was selected and its alginate lyase activity was increased by 3.87-fold (reaching 46.12 EU/mg) over that of the parent strain. An extracellular alginate lyase was purified from Vibrio sp. 510-64 cultural supernatant by successive fractionation on DEAE Sepharose FF and two steps of Superdex 75. The purified enzyme yielded a single band on SDS-PAGE with the molecular weight of 34.6 kDa. Data of the N-terminal amino acid sequence indicated that this protein might be a novel alginate lyase. The substrate specificity results demonstrated that the alginate lyase had the specificity for poly G block.

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.

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®.

Efficacy of chitosan and sodium alginate scaffolds for repair of spinal cord injury in rats

PubMed Central

Yao, Zi-ang; Chen, Feng-jia; Cui, Hong-li; Lin, Tong; Guo, Na; Wu, Hai-ge

2018-01-01

Spinal cord injury results in the loss of motor and sensory pathways and spontaneous regeneration of adult mammalian spinal cord neurons is limited. Chitosan and sodium alginate have good biocompatibility, biodegradability, and are suitable to assist the recovery of damaged tissues, such as skin, bone and nerve. Chitosan scaffolds, sodium alginate scaffolds and chitosan-sodium alginate scaffolds were separately transplanted into rats with spinal cord hemisection. Basso-Beattie-Bresnahan locomotor rating scale scores and electrophysiological results showed that chitosan scaffolds promoted recovery of locomotor capacity and nerve transduction of the experimental rats. Sixty days after surgery, chitosan scaffolds retained the original shape of the spinal cord. Compared with sodium alginate scaffolds- and chitosan-sodium alginate scaffolds-transplanted rats, more neurofilament-H-immunoreactive cells (regenerating nerve fibers) and less glial fibrillary acidic protein-immunoreactive cells (astrocytic scar tissue) were observed at the injury site of experimental rats in chitosan scaffold-transplanted rats. Due to the fast degradation rate of sodium alginate, sodium alginate scaffolds and composite material scaffolds did not have a supporting and bridging effect on the damaged tissue. Above all, compared with sodium alginate and composite material scaffolds, chitosan had better biocompatibility, could promote the regeneration of nerve fibers and prevent the formation of scar tissue, and as such, is more suitable to help the repair of spinal cord injury. PMID:29623937

40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

Code of Federal Regulations, 2014 CFR

2014-07-01

... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

Code of Federal Regulations, 2010 CFR

2010-07-01

... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

Protection of color and chemical degradation of anthocyanin from purple corn (Zea mays L.) by zinc ions and alginate through chemical interaction in a beverage model.

PubMed

Luna-Vital, Diego; Cortez, Regina; Ongkowijoyo, Paulina; Gonzalez de Mejia, Elvira

2018-03-01

Anthocyanin-rich purple corn pericarp water extract (PCW) has the potential to be used as a natural pigment in beverages. However, it has a limited shelf-life in aqueous solutions. The aim was to evaluate the effect of zinc ion (Zn 2+ ) and alginate on color and chemical stability of anthocyanins from colored corn (PCW) in a beverage model for 12weeks. PCW was incorporated to Kool-Aid® Invisible™ along with ZnCl 2 and/or alginate. Individual ANC were quantified through HPLC, and color stability was evaluated through the CIE-L*a*b* color system. Complexation between PCW and Zn/alginate was evaluated with fluorescence spectroscopy. The combination of Zn and alginate was the most effective treatment improving the half-life of total ANC concentration (10.4weeks), cyanidin-3-O-glucoside (7.5weeks) and chroma (18.4weeks), compared to only PCW (6.6, 4.5 and 12.7weeks, respectively). Zn and alginate had bimolecular quenching constants (Zn k q : 3.4×10 11 M -1 S -1 and AA k q : 1.0×10 12 M -1 S -1 ) suggesting that fluorescence quenching was binding rather than collisional. Results suggested that Zn/alginate interacted with ANC from purple corn slowing its chemical degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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...

A novel dressing for the combined delivery of platelet lysate and vancomycin hydrochloride to chronic skin ulcers: Hyaluronic acid particles in alginate matrices.

PubMed

Rossi, S; Mori, M; Vigani, B; Bonferoni, M C; Sandri, G; Riva, F; Caramella, C; Ferrari, F

2018-06-15

The aim of the present work was to develop a medication allowing for the combined delivery of platelet lysate (PL) and an anti-infective model drug, vancomycin hydrochloride (VCM), to chronic skin ulcers. A simple method was set up for the preparation of hyaluronic acid (HA) core-shell particles, loaded with PL and coated with calcium alginate, embedded in a VCM containing alginate matrix. Two different CaCl 2 concentrations were investigated to allow for HA/PL core-shell particle formation. The resulting dressings were characterized for mechanical and hydration properties and tested in vitro (on fibroblasts) and ex-vivo (on skin biopsies) for biological activity. They were found of sufficient mechanical strength to withstand packaging and handling stress and able to absorb a high amount of wound exudate and to form a protective gel on the lesion area. The CaCl 2 concentration used for shell formation did not affect VCM release from the alginate matrix, but strongly modified the release of PGFAB (chosen as representative of growth factors present in PL) from HA particles. In vitro and ex vivo tests provided sufficient proof of concept of the ability of dressings to improve skin ulcers healing. Copyright © 2018 Elsevier B.V. All rights reserved.

Bardoxolone methyl (BARD) ameliorates aristolochic acid (AA)-induced acute kidney injury through Nrf2 pathway.

PubMed

Wu, Juan; Liu, Xinhui; Fan, Jinjin; Chen, Wenfang; Wang, Juan; Zeng, Youjia; Feng, Xiaorang; Yu, Xueqing; Yang, Xiao

2014-04-06

Bardoxolone methyl (BARD) is an antioxidant modulator that acts through induction of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. This study aimed to investigate the role of BARD in protecting kidneys from aristolochic acid (AA)-induced acute kidney injury (AKI). Male C57BL/6 mice received intraperitoneal (i.p.) injections of aristolochic acid I (AAI) (5mg/kg/day) for 5 days to produce acute AA nephropathy (AAN) model. BARD (10mg/kg/day, i.p.) was applied for 7 consecutive days, starting 2 days prior to AAI administration. The mice in the AA group showed AKI as evidenced by worsening kidney function evaluated by blood urea nitrogen (BUN) and serum creatinine (SCr) levels, and severe tubulointerstitial injury marked by massive tubule necrosis in kidney tissues. BARD significantly reduced BUN and SCr levels which were elevated by AAI. Additionally, AAI-induced histopathological renal damage was ameliorated by BARD. Furthermore, the expression of Nrf2 was reduced, and its repressor Kelch-like ECH-associated protein 1 (Keap1) was increased significantly, whereas heme oxygenase-1 (HO-1) was upregulated and NAD(P)H quinone oxidoreductase-1 (NQO1) was barely increased in the cytoplasm of tubules in kidneys after treatment with AAI. BARD significantly upregulated renal Nrf2, NQO1 and HO-1 expression and downregulated Keap1 expression compared with those in the AA group. Moreover, it was found that Nrf2 was expressed both in the cytoplasm and nuclear of glomeruli and tubules, whereas NQO1 and HO-1 were localized in the cytoplasm of tubules only. In conclusion, AA-induced acute renal injury was associated with impaired Nrf2 activation and expression of its downstream target genes in renal tissues. BARD prevented renal damage induced by AAI, and this renoprotective effect may be exerted by activating the Nrf2 signaling pathway and increasing expression of the downstream target genes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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...

A simple approach for morphology tailoring of alginate particles by manipulation ionic nature of polyurethanes.

PubMed

Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

2014-05-01

A number of different ionic aqueous polyurethane dispersions (PUDs) were synthesized based on NCO-terminated prepolymers. Two different anionic and cationic polyurethane samples were synthesized using dimethylol propionic acid and N-methyldiethanolamine emulsifiers, respectively. Then, proper amounts of PUDs and sodium alginate were mixed to obtain a number of aqueous polyurethane dispersions-sodium alginate (PUD/SA) elastomers. The chemical structure, thermal, morphological, thermo-mechanical and mechanical properties, and hydrophilicity content of the prepared samples were studied by FTIR, EDX, DSC, TGA, SEM, DMTA, tensile testing and contact angle techniques. The cationic polyurethanes and their blends with sodium alginate showed excellent miscibility and highly stretchable properties, while the samples containing anionic polyurethanes and alginate illustrated a poor compatibility and no significant miscibility. The morphology of alginate particles shifted from nanoparticles to microparticles by changing the nature of PUDs from cationic to anionic types. The final cationic elastomers not only showed better mechanical properties but also were formulated easier than anionic samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Enzymatically cross-linked injectable alginate-g-pyrrole hydrogels for neovascularization.

PubMed

Devolder, Ross; Antoniadou, Eleni; Kong, Hyunjoon

2013-11-28

Microparticles capable of releasing protein drugs are often incorporated into injectable hydrogels to minimize their displacement at an implantation site, reduce initial drug burst, and further control drug release rates over a broader range. However, there is still a need to develop methods for releasing drug molecules over extended periods of time, in order to sustain the bioactivity of drug molecules at an implantation site. In this study, we hypothesized that a hydrogel formed through the cross-linking of pyrrole units linked to a hydrophilic polymer would release protein drugs in a more sustained manner, because of an enhanced association between cross-linked pyrrole groups and the drug molecules. To examine this hypothesis, we prepared hydrogels of alginate substituted with pyrrole groups, alginate-g-pyrrole, through a horse-radish peroxidase (HRP)-activated cross-linking of the pyrrole groups. The hydrogels were encapsulated with poly(lactic-co-glycolic acid) (PLGA) microparticles loaded with vascular endothelial growth factor (VEGF). The resulting hydrogel system released VEGF in a more sustained manner than Ca(2+) alginate or Ca(2+) alginate-g-pyrrole gel systems. Finally, implantations of the VEGF-releasing HRP-activated alginate-g-pyrrole hydrogel system on chicken chorioallantoic membranes resulted in the formation of blood vessels in higher densities and with larger diameters, compared to other control conditions. Overall, the drug releasing system developed in this study will be broadly useful for regulating release rates of a wide array of protein drugs, and further enhance the quality of protein drug-based therapies. © 2013 Elsevier B.V. All rights reserved.

Optimization of culturing condition and medium composition for the production of alginate lyase by a marine Vibrio sp. YKW-34

NASA Astrophysics Data System (ADS)

Fu, Xiaoting; Lin, Hong; Kim, Sang Moo

2008-02-01

Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the production of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL-1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25°C. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had negative effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had positive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of alginate lyase production under the optimized condition was described. The optimal harvest time was 48 h.

Alginate copper oxide nano-biocomposite as a novel material for amperometric glucose biosensing.

PubMed

Buk, Vuslat; Emregul, Emel; Emregul, Kaan Cebesoy

2017-05-01

A novel amperometric glucose biosensor based on alginate-CuO nano-biocomposite and glucose oxidase (GOD) film was developed and characterized. The properties of the alginate-CuO-GOD film were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric measurements were employed to characterize the analytical performance of the biosensor. Several parameters including amount of alginate, concentration of GOD and cross-linkers, amount of CuO nanoparticles, and effect of pH were studied and optimized. Under optimal conditions, the developed alginate-CuO-GOD biosensor was shown to have two linear ranges; from 0.04mM to 3mM (with a correlation coefficient of 0.9996 and the sensitivity of 30.443μAmM -1 cm -2 ) and from 4mM to 35mM (with a correlation coefficient of 0.9994 and the sensitivity of 7.205μAmM -1 cm -2 ). The overall detection limit was estimated to be 1.6μM (signal-to-noise ratio of 3) and the K m value of 2.82mM. The biosensor exhibited rather good performance with long-term stability (remainder of activity is 78% after 15days) and significant specificity for glucose when compared to possible interfering molecules such as ascorbic acid, uric acid and acetaminophen. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed

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

2015-09-30

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

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.

Electrosynthesis of magnetoresponsive microrobot for targeted drug delivery using calcium alginate.

PubMed

Chengzhi Hu; Riederer, Katharina; Klemmer, Michael; Pane, Salvador; Nelson, Bradley J

2016-08-01

Targeted drug delivery systems deliver drugs precisely to a specific targeted site inside the body, and can also release the drugs with controlled kinetics to prolong the efficacy of single dose administration. The advantageous properties of hydrogels make them attractive for use in the area of drug delivery. Calcium alginate is a pH sensitive hydrogel stable in acidic media and soluble in basic media. This enables the hydrogel to absorb and release aqueous solutions at certain ranges of pH values. By absorbing an aqueous solution containing a drug, an active drug release can be triggered at a specified range of pH value. In this paper, we combined calcium alginate with cobalt nickel (CoNi) in a cylindrical hybrid micro robot by electrodeposition. The designed microrobot can be wirelessly actuated with an external magnetic manipulation system and, hence, targeted to a specific location in the human body. At this specific location, characterized by its pH range, the absorbed drug will be released. Here, the fabrication steps of the specified microrobot are characterized, namely the production of a template on a silicon chip and the subsequent template-assisted electrodeposition of CoNi and alginate. Additionally, the dynamics of drug release of calcium alginate is studied.

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

PubMed

Fawzy, Ahmed

2016-03-15

The kinetics of oxidation of alginate (Alg) and pectate (Pec) carbohydrate biopolymers was studied by spectrophotometry in aqueous perchloric and sulfuric acid solutions at fixed ionic strengths and temperature. In both acids, the reactions showed a first order dependence on [Ce(IV)], whereas the orders with respect to biopolymer concentrations are less than unity. In perchloric acid, the reactions exhibited less than unit orders with respect to [H(+)] whereas those proceeded in sulfuric acid showed negative fractional-first order dependences on [H(+)]. The effect of ionic strength and dielectric constant was studied. Probable mechanistic schemes for oxidation reactions were proposed. In both acids, the final oxidation products were characterized as mono-keto derivatives of both biopolymers. The activation parameters with respect to the slow step of the mechanisms were computed and discussed. The rate laws were derived and the reaction constants involved in the different steps of the mechanisms were calculated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterisation of physico-mechanical properties and degradation potential of calcium alginate beads for use in embolisation.

PubMed

Forster, Richard E J; Thürmer, Frank; Wallrapp, Christine; Lloyd, Andrew W; Macfarlane, Wendy; Phillips, Gary J; Boutrand, Jean-Pierre; Lewis, Andrew L

2010-07-01

High molecular weight alginate beads with 59% mannuronic acid content or 68% guluronic acid were prepared using a droplet generator and crosslinked in calcium chloride. The alginate beads were compared to current embolisation microspheres for compressibility and monitored over 12 weeks for size and weight change at 37 degrees C in low volumes of ringers solutions. A sheep uterine model was used to analyse bead degradation and inflammatory response over 12 weeks. Both the in vitro and in vivo data show good delivery, with a compressibility similar to current embolic beads. In vitro, swelling was noted almost immediately and after 12 weeks the first signs of degradation were noted. No difference was noted in vivo. This study has shown that high molecular weight alginate gel beads were well tolerated by the body, but beads associated with induced thrombi were susceptible to inflammatory cell infiltration. The beads were shown to be easy to handle and were still observable after 3 months in vivo. The beads were robust enough to be delivered through a 2.7 Fr microcatheter. This study has demonstrated that high molecular weight, high purity alginate bead can be considered as semi-permanent embolisation beads, with the potential to bioresorb over time.

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.

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.

Copper(II)-mediated thermolysis of alginates: a model kinetic study on the influence of metal ions in the thermochemical processing of macroalgae

PubMed Central

Rowbotham, J. S.; Dyer, P. W.; Greenwell, H. C.; Selby, D.; Theodorou, M. K.

2013-01-01

Thermochemical processing methods such as pyrolysis are of growing interest as a means of converting biomass into fuels and commodity chemicals in a sustainable manner. Macroalgae, or seaweed, represent a novel class of feedstock for pyrolysis that, owing to the nature of the environments in which they grow coupled with their biochemistry, naturally possess high metal contents. Although the impact of metals upon the pyrolysis of terrestrial biomass is well documented, their influence on the thermochemical conversion of marine-derived feeds is largely unknown. Furthermore, these effects are inherently difficult to study, owing to the heterogeneous character of natural seaweed samples. The work described in this paper uses copper(II) alginate, together with alginic acid and sodium alginate as model compounds for exploring the effects of metals upon macroalgae thermolysis. A thermogravimetric analysis–Fourier transform infrared spectroscopic study revealed that, unusually, Cu2+ ions promote the onset of pyrolysis in the alginate polymer, with copper(II) alginate initiating rapid devolatilization at 143°C, 14°C lower than alginic acid and 61°C below the equivalent point for sodium alginate. Moreover, this effect was mirrored in a sample of wild Laminaria digitata that had been doped with Cu2+ ions prior to pyrolysis, thus validating the use of alginates as model compounds with which to study the thermolysis of macroalgae. These observations indicate the varying impact of different metal species on thermochemical behaviour of seaweeds and offer an insight into the pyrolysis of brown macroalgae used in phytoremediation of metal-containing waste streams. PMID:24427515

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

Strategies to overcome pH-dependent solubility of weakly basic drugs by using different types of alginates.

PubMed

Gutsche, S; Krause, M; Kranz, H

2008-12-01

Weakly basic drugs demonstrate higher solubility at lower pH, thus often leading to faster drug release at lower pH. The objective of this study was to achieve pH-independent release of weakly basic drugs from extended release formulations based on the naturally occurring polymer sodium alginate. Three approaches to overcome the pH-dependent solubility of the weakly basic model drug verapamil hydrochloride were investigated. First, matrix tablets were prepared by direct compression of drug substance with different types of sodium alginate only. Second, pH-modifiers were added to the drug/alginate matrix systems. Third, press-coated tablets consisting of an inner pH-modifier tablet core and an outer drug/sodium alginate coat were prepared. pH-Independent drug release was achieved from matrix tablets consisting of selected alginates and drug substance only. Alginates are better soluble at higher pH. Therefore, they are able to compensate the poor solubility of weakly basic drugs at higher pH as the matrix of the tablets dissolves faster. This approach was successful when using alginates that demonstrated fast hydration and erosion at higher pH. The approach failed for alginates with less-pronounced erosion at higher pH. The addition of fumaric acid to drug/alginate-based matrix systems decreased the microenvironmental pH within the tablets thus increasing the solubility of the weakly basic drug at higher pH. Therefore, pH-independent drug release was achieved irrespective of the type of alginate used. Drug release from press-coated tablets did not provide any further advantages as compound release remained pH-dependent.

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.

Alginic acid cell entrapment: a novel method for measuring in vivo macrophage cholesterol homeostasis

PubMed Central

Sontag, Timothy J.; Chellan, Bijoy; Bhanvadia, Clarissa V.; Getz, Godfrey S.; Reardon, Catherine A.

2015-01-01

Macrophage conversion to atherosclerotic foam cells is partly due to the balance of uptake and efflux of cholesterol. Cholesterol efflux from cells by HDL and its apoproteins for subsequent hepatic elimination is known as reverse cholesterol transport. Numerous methods have been developed to measure in vivo macrophage cholesterol efflux. Most methods do not allow for macrophage recovery for analysis of changes in cellular cholesterol status. We describe a novel method for measuring cellular cholesterol balance using the in vivo entrapment of macrophages in alginate, which retains incorporated cells while being permeable to lipoproteins. Recipient mice were injected subcutaneously with CaCl2 forming a bubble into which a macrophage/alginate suspension was injected, entrapping the macrophages. Cells were recovered after 24 h. Cellular free and esterified cholesterol mass were determined enzymatically and normalized to cellular protein. Both normal and cholesterol loaded macrophages undergo measureable changes in cell cholesterol when injected into WT and apoA-I-, LDL-receptor-, or apoE-deficient mice. Cellular cholesterol balance is dependent on initial cellular cholesterol status, macrophage cholesterol transporter expression, and apolipoprotein deficiency. Alginate entrapment allows for the in vivo measurement of macrophage cholesterol homeostasis and is a novel platform for investigating the role of genetics and therapeutic interventions in atherogenesis. PMID:25465389

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

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

PubMed

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

2015-01-01

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

Hyaluronic Acid/Collagen Hydrogel as an Alternative to Alginate for Long-Term Immunoprotected Islet Transplantation.

PubMed

Harrington, Stephen; Williams, Janette; Rawal, Sonia; Ramachandran, Karthik; Stehno-Bittel, Lisa

2017-10-01

Alginate has long been the material of choice for immunoprotection of islets due to its low cost and ability to easily form microspheres. Unfortunately, this seaweed-derived material is notoriously prone to fibrotic overgrowth in vivo, resulting in premature graft failure. The purpose of this study was to test an alternative, hyaluronic acid (HA-COL), for in vitro function, viability, and allogeneic islet transplant outcomes in diabetic rats. In vitro studies indicated that the HA-COL gel had diffusion characteristics that would allow small molecules such as glucose and insulin to enter and exit the gel, whereas larger molecules (70 and 500 kDa dextrans) were impeded from diffusing past the gel edge in 24 h. Islets encapsulated in HA-COL hydrogel showed significantly improved in vitro viability over unencapsulated islets and retained their morphology and glucose sensitivity for 28 days. When unencapsulated allogeneic islet transplants were administered to the omentum of outbred rats, they initially were normoglycemic, but by 11 days returned to hyperglycemia. Immunohistological examination of the grafts and surrounding tissue indicated strong graft rejection. By comparison, when using the same outbred strain of rats, allogeneic transplantation of islets within the HA-COL gel reversed long-term diabetes and prevented graft rejection in all animals. Animals were sacrificed at 40, 52, 64, and 80 weeks for evaluation, and all were non-diabetic at sacrifice. Explanted grafts revealed viable islets in the transplant site as well as intact hydrogel, with little or no evidence of fibrotic overgrowth or cellular rejection. The results of these studies demonstrate great potential for HA-COL hydrogel as an alternative to sodium alginate for long-term immunoprotected islet transplantation.

A Novel Aldo-Keto Reductase, HdRed, from the Pacific Abalone Haliotis discus hannai, Which Reduces Alginate-derived 4-Deoxy-l-erythro-5-hexoseulose Uronic Acid to 2-Keto-3-deoxy-d-gluconate*

PubMed Central

Mochizuki, Shogo; Nishiyama, Ryuji; Inoue, Akira; Ojima, Takao

2015-01-01

Abalone feeds on brown seaweeds and digests seaweeds' alginate with alginate lyases (EC 4.2.2.3). However, it has been unclear whether the end product of alginate lyases (i.e. unsaturated monouronate-derived 4-deoxy-l-erythro-5-hexoseulose uronic acid (DEH)) is assimilated by abalone itself, because DEH cannot be metabolized via the Embden-Meyerhof pathway of animals. Under these circumstances, we recently noticed the occurrence of an NADPH-dependent reductase, which reduced DEH to 2-keto-3-deoxy-d-gluconate, in hepatopancreas extract of the pacific abalone Haliotis discus hannai. In the present study, we characterized this enzyme to some extent. The DEH reductase, named HdRed in the present study, could be purified from the acetone-dried powder of hepatopancreas by ammonium sulfate fractionation followed by conventional column chromatographies. HdRed showed a single band of ∼40 kDa on SDS-PAGE and reduced DEH to 2-keto-3-deoxy-d-gluconate with an optimal temperature and pH at around 50 °C and 7.0, respectively. HdRed exhibited no appreciable activity toward 28 authentic compounds, including aldehyde, aldose, ketose, α-keto-acid, uronic acid, deoxy sugar, sugar alcohol, carboxylic acid, ketone, and ester. The amino acid sequence of 371 residues of HdRed deduced from the cDNA showed 18–60% identities to those of aldo-keto reductase (AKR) superfamily enzymes, such as human aldose reductase, halophilic bacterium reductase, and sea hare norsolorinic acid (a polyketide derivative) reductase-like protein. Catalytic residues and cofactor binding residues known in AKR superfamily enzymes were fairly well conserved in HdRed. Phylogenetic analysis for HdRed and AKR superfamily enzymes indicated that HdRed is an AKR belonging to a novel family. PMID:26555267

A Novel Aldo-Keto Reductase, HdRed, from the Pacific Abalone Haliotis discus hannai, Which Reduces Alginate-derived 4-Deoxy-L-erythro-5-hexoseulose Uronic Acid to 2-Keto-3-deoxy-D-gluconate.

PubMed

Mochizuki, Shogo; Nishiyama, Ryuji; Inoue, Akira; Ojima, Takao

2015-12-25

Abalone feeds on brown seaweeds and digests seaweeds' alginate with alginate lyases (EC 4.2.2.3). However, it has been unclear whether the end product of alginate lyases (i.e. unsaturated monouronate-derived 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH)) is assimilated by abalone itself, because DEH cannot be metabolized via the Embden-Meyerhof pathway of animals. Under these circumstances, we recently noticed the occurrence of an NADPH-dependent reductase, which reduced DEH to 2-keto-3-deoxy-D-gluconate, in hepatopancreas extract of the pacific abalone Haliotis discus hannai. In the present study, we characterized this enzyme to some extent. The DEH reductase, named HdRed in the present study, could be purified from the acetone-dried powder of hepatopancreas by ammonium sulfate fractionation followed by conventional column chromatographies. HdRed showed a single band of ∼ 40 kDa on SDS-PAGE and reduced DEH to 2-keto-3-deoxy-D-gluconate with an optimal temperature and pH at around 50 °C and 7.0, respectively. HdRed exhibited no appreciable activity toward 28 authentic compounds, including aldehyde, aldose, ketose, α-keto-acid, uronic acid, deoxy sugar, sugar alcohol, carboxylic acid, ketone, and ester. The amino acid sequence of 371 residues of HdRed deduced from the cDNA showed 18-60% identities to those of aldo-keto reductase (AKR) superfamily enzymes, such as human aldose reductase, halophilic bacterium reductase, and sea hare norsolorinic acid (a polyketide derivative) reductase-like protein. Catalytic residues and cofactor binding residues known in AKR superfamily enzymes were fairly well conserved in HdRed. Phylogenetic analysis for HdRed and AKR superfamily enzymes indicated that HdRed is an AKR belonging to a novel family. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

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.

Sodium alginate as feed additive in cultured sea bream (Sparus aurata): does it modify the quality of the flesh?

PubMed

Peso-Echarri, P; Frontela-Saseta, C; Santaella-Pascual, M; García-Alcázar, A; Abdel, I; Ros-Berruezo, G; Martínez-Graciá, C

2012-11-15

The objective of this study was to evaluate the effect of sodium alginate obtained from brown seaweed as a prebiotic supplement to the feed of reared sea bream (Sparus aurata). Addition of the alginate to a control diet was investigated at both concentrations 2% and 5%. Proximate composition in the flesh were not modified significantly by sodium alginate inclusion in the diet of the sea bream; however the fat and ash content in the specimens supplemented with 5% alginate were found to be significantly higher than those found in individuals who were fed the control diet. No significant differences in mineral content, fatty acid profiles, cholesterol content, texture parameters and sensory acceptability among the three studied groups. Results obtained in this study offer support for the use of alginate as a feed additive in sea bream diets since no significant effects were found in the flesh quality and characteristics of commercial size sea bream. Copyright © 2012 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

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.

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.

Biodegradable multilayer barrier films based on alginate/polyethyleneimine and biaxially oriented poly(lactic acid).

PubMed

Gu, Chun-Hong; Wang, Jia-Jun; Yu, Yang; Sun, Hui; Shuai, Ning; Wei, Bing

2013-02-15

A layer-by-layer (LBL) approach was used to assemble alternating layers of sodium alginate (ALG)/polyethyleneimine (PEI) on biaxially oriented poly(lactic acid) (BOPLA) films in order to produce bio-based all-polymer thin films with low gas permeability. Increasing the depositing of ALG and PEI from 0 to 30 layers results in large thickness variations (from 0 to 3.92 μm). After 30 ALG/PEI layers are deposited, the resulting assembly has an OTR of 1.22 cm(3)/(m(2) day atm). When multiplied by thickness, the resulting oxygen permeability (OP) is found to be less than 3.8×10(-17) cm(3) cm/cm(2) s Pa, which is almost 3 orders of magnitude lower than that of uncoated BOPLA film (1.8×10(-14) cm(3)cm/cm(2) s Pa). At the same time, the resulting multilayer-coated BOPLA films maintain high optical clarity and tensile properties. This unique barrier thin film has become a promising alternative to non-biodegradable synthetic food packaging materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pervaporation dehydration of ethanol by hyaluronic acid/sodium alginate two-active-layer composite membranes.

PubMed

Gao, Chengyun; Zhang, Minhua; Ding, Jianwu; Pan, Fusheng; Jiang, Zhongyi; Li, Yifan; Zhao, Jing

2014-01-01

The composite membranes with two-active-layer (a capping layer and an inner layer) were prepared by sequential spin-coatings of hyaluronic acid (HA) and sodium alginate (NaAlg) on the polyacrylonitrile (PAN) support layer. The SEM showed a mutilayer structure and a distinct interface between the HA layer and the NaAlg layer. The coating sequence of two-active-layer had an obvious influence on the pervaporation dehydration performance of membranes. When the operation temperature was 80 °C and water concentration in feed was 10 wt.%, the permeate fluxes of HA/Alg/PAN membrane and Alg/HA/PAN membrane were similar, whereas the separation factor were 1130 and 527, respectively. It was found that the capping layer with higher hydrophilicity and water retention capacity, and the inner layer with higher permselectivity could increase the separation performance of the composite membranes. Meanwhile, effects of operation temperature and water concentration in feed on pervaporation performance as well as membrane properties were studied. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a novel colorimetric sensor based on alginate beads for monitoring rainbow trout spoilage.

PubMed

Majdinasab, Marjan; Hosseini, Seyed Mohammad Hashem; Sepidname, Marziyeh; Negahdarifar, Manizheh; Li, Peiwu

2018-05-01

Alginate is a non-toxic, renewable, and linear copolymer obtained from the brown algae Laminaria digitata that can be easily shaped into beads. Its good gel forming properties have made it useful for entrapping food and pharmaceutical ingredients. In this study, alginate beads were used in a novel application as a colorimetric sensor in food intelligent packaging. Colorimetric sensor was developed through entrapping red cabbage extract as a pH indicator in alginate beads. The pH indicator beads were used in rainbow trout packaging for monitoring fillets spoilage. Color change of beads during fish storage was measured using the CIELab method. The alginate bead colorimetric sensor is validated by measuring total volatile basic nitrogen (TVB-N) levels and microbial populations in fish samples. Moreover, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated during storage. Results indicated that increasing the bacterial population during storage and production of proteolytic enzymes resulted in protein degradation, accumulation of volatile amine compounds, increase in the pH and finally color change of alginate beads. The values of TVB-N, pH, PV and TBARS increased with time of storage. The results of TVB-N and microbial growth were in accordance with color change of beads and CIELab data. Therefore, the proposed system enjoys a high sensitivity to pH variations and is capable of monitoring the spoilage of fish or other protein-rich products through its wide range of color changes. The alginate beads containing the red cabbage extract can, thus, be used as a low-cost colorimetric sensor for intelligent packaging applications.

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.

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.

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.

Comparison of a dimethicone/antacid (Asilone gel) with an alginate/antacid (Gaviscon liquid) in the management of reflux oesophagitis.

PubMed Central

Smart, H L; Atkinson, M

1990-01-01

Fifty-three patients with symptomatic reflux oesophagitis were entered into a single centre randomized study comparing the effects of a dimethicone/antacid (Asilone Gel) and an alginate/antacid (Gaviscon liquid) on symptoms and endoscopic changes over an 8-week period. Both treatments significantly improved heartburn, acid regurgitation and flatulence. Dimethicone/antacid but not alginate/antacid, produced a significant improvement in oesophagitis, oesophageal ulceration and histological grade of inflammation over the 8-week treatment period so that 14 patients treated with dimethicone/antacid and 10 with alginate/antacid had normal endoscopic oesophageal appearances at the end of the study. The difference in improvement between the two patient groups did not reach significance however, except for dimethicone/antacid improving histological changes (P less than 0.05). These findings suggest that dimethicone/antacid and alginate/antacid are equally effective in treating symptomatic reflux oesophagitis although dimethicone/antacid may have an advantage in improving oesophageal histological appearances. PMID:2213800

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.

Release Behavior and Antibacterial Activity of Chitosan/Alginate Blends with Aloe vera and Silver Nanoparticles

PubMed Central

Gómez Chabala, Luisa Fernanda; Cuartas, Claudia Elena Echeverri; López, Martha Elena Londoño

2017-01-01

Aloe vera is a perennial plant employed for medical, pharmaceutical and cosmetic purposes that is rich in amino acids, enzymes, vitamins and polysaccharides, which are responsible for its therapeutic properties. Incorporating these properties into a biopolymer film obtained from alginate and chitosan allowed the development of a novel wound dressing with antibacterial capacity and healing effects to integrate the antibacterial capacity of silver nanoparticles with the healing and emollient properties of Aloe vera gel. Three alginate-chitosan matrices were obtained through blending methods using different proportions of alginate, chitosan, the Aloe vera (AV) gel and silver nanoparticles (AgNps), which were incorporated into the polymeric system through immersion methods. Physical, chemical and antibacterial characteristics were evaluated in each matrix. Interaction between alginate and chitosan was identified using the Fourier transform infrared spectroscopy technique (FTIR), porosity was studied using scanning electron microscopy (SEM), swelling degree was calculated by difference in weight, Aloe vera gel release capacity was estimated by applying a drug model (Peppas) and finally antibacterial capacity was evaluated against S. Aureus and P. aeruginosa. Results show that alginate-chitosan (A (1:3 Chit 1/Alg 1); B (1:3 Chit 1.5/Alg 1) and C (3:1 Chit 1/Alg 1/B12)) matrices with Aloe vera (AV) gel and silver nanoparticles (AgNps) described here displayed antibacterial properties and absorption and Aloe vera release capacity making it a potential wound dressing for minor injuries. PMID:29064431

Release Behavior and Antibacterial Activity of Chitosan/Alginate Blends with Aloe vera and Silver Nanoparticles.

PubMed

Gómez Chabala, Luisa Fernanda; Cuartas, Claudia Elena Echeverri; López, Martha Elena Londoño

2017-10-24

Aloe vera is a perennial plant employed for medical, pharmaceutical and cosmetic purposes that is rich in amino acids, enzymes, vitamins and polysaccharides, which are responsible for its therapeutic properties. Incorporating these properties into a biopolymer film obtained from alginate and chitosan allowed the development of a novel wound dressing with antibacterial capacity and healing effects to integrate the antibacterial capacity of silver nanoparticles with the healing and emollient properties of Aloe vera gel. Three alginate-chitosan matrices were obtained through blending methods using different proportions of alginate, chitosan, the Aloe vera (AV) gel and silver nanoparticles (AgNps), which were incorporated into the polymeric system through immersion methods. Physical, chemical and antibacterial characteristics were evaluated in each matrix. Interaction between alginate and chitosan was identified using the Fourier transform infrared spectroscopy technique (FTIR), porosity was studied using scanning electron microscopy (SEM), swelling degree was calculated by difference in weight, Aloe vera gel release capacity was estimated by applying a drug model (Peppas) and finally antibacterial capacity was evaluated against S. Aureus and P. aeruginosa . Results show that alginate-chitosan (A (1:3 Chit 1/Alg 1); B (1:3 Chit 1.5/Alg 1) and C (3:1 Chit 1/Alg 1/B12)) matrices with Aloe vera (AV) gel and silver nanoparticles (AgNps) described here displayed antibacterial properties and absorption and Aloe vera release capacity making it a potential wound dressing for minor injuries.

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.

Time-Dependent Effect of Encapsulating Alginate Hydrogel on Neurogenic Potential

PubMed Central

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

2015-01-01

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

Sodium alginate/carboxymethyl cellulose films containing pyrogallic acid: physical and antibacterial properties.

PubMed

Han, Yingying; Wang, Lijuan

2017-03-01

Antibacterial films were prepared using sodium alginate (SA) and carboxymethyl cellulose (CMC) as a matrix, glycerin as a plasticizer and CaCl 2 as a cross-linking agent, and by incorporating the natural antibacterial agent pyrogallic acid (PA). The present study describes the microstructure and the physical, barrier, mechanical, optical and antibacterial properties of blended films prepared by incorporating different concentrations of PA into the SA/CMC matrix. The microstructure of the films was investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, which revealed that PA interacts with the SA/CMC matrix through hydrogen bonding. Moreover, the incorporation of PA increased the moisture content, water vapor permeability and oxygen permeability of SA/CMC films. Films containing 40 g kg -1 of PA had the highest elongation at break result (39.60%). Compared with pure SA/CMC films, the incorporation of PA improved the barrier properties against ultraviolet light; however, it decreased the color parameter L* value and increased the a* and b* values of the films. Furthermore, films with PA, especially at higher concentrations, were more effective against Escherichia coli and Staphylococcus aureus. Antibacterial SA/CMC films incorporating PA appear to have good potential to enhance the safety of foods and food products. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15

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

Ochiai, Akihito; Yamasaki, Masayuki; Mikami, Bunzo

2006-05-01

The crystallization and preliminary X-ray characterization of a family PL-15 exotype alginate lyase are presented. Almost all alginate lyases depolymerize alginate in an endolytical fashion via a β-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P2{sub 1} and diffracted to 2.8 Å resolution, with unit-cell parameters a = 107.7, bmore » = 108.3, c = 149.5 Å, β = 91.5°.« less

The cytochrome P450 2AA gene cluster in zebrafish (Danio rerio): Expression of CYP2AA1 and CYP2AA2 and response to phenobarbital-type inducers

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

Kubota, Akira; Bainy, Afonso C.D.; Departamento de Bioquímica, CCB, Universidade Federal de Santa Catarina, Florianopolis, SC 88040-900

2013-10-01

The cytochrome P450 (CYP) 2 gene family is the largest and most diverse CYP gene family in vertebrates. In zebrafish, we have identified 10 genes in a new subfamily, CYP2AA, which does not show orthology to any human or other mammalian CYP genes. Here we report evolutionary and structural relationships of the 10 CYP2AA genes and expression of the first two genes, CYP2AA1 and CYP2AA2. Parsimony reconstruction of the tandem duplication pattern for the CYP2AA cluster suggests that CYP2AA1, CYP2AA2 and CYP2AA3 likely arose in the earlier duplication events and thus are most diverged in function from the other CYP2AAs.more » On the other hand, CYP2AA8 and CYP2AA9 are genes that arose in the latest duplication event, implying functional similarity between these two CYPs. A molecular model of CYP2AA1 showing the sequence conservation across the CYP2AA cluster reveals that the regions with the highest variability within the cluster map onto CYP2AA1 near the substrate access channels, suggesting differing substrate specificities. Zebrafish CYP2AA1 transcript was expressed predominantly in the intestine, while CYP2AA2 was most highly expressed in the kidney, suggesting differing roles in physiology. In the liver CYP2AA2 expression but not that of CYP2AA1, was increased by 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and, to a lesser extent, by phenobarbital (PB). In contrast, pregnenolone 16α-carbonitrile (PCN) increased CYP2AA1 expression, but not CYP2AA2 in the liver. The results identify a CYP2 subfamily in zebrafish that includes genes apparently induced by PB-type chemicals and PXR agonists, the first concrete in vivo evidence for a PB-type response in fish. - Highlights: • A tandemly duplicated cluster of ten CYP2AA genes was described in zebrafish. • Parsimony and duplication analyses suggest pathways to CYP2AA diversity. • Homology models reveal amino acid positions possibly related to functional diversity. • The CYP2AA locus does not share

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

PubMed

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

2017-06-29

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

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.

Arachidonic Acid Stress Impacts Pneumococcal Fatty Acid Homeostasis

PubMed Central

Eijkelkamp, Bart A.; Begg, Stephanie L.; Pederick, Victoria G.; Trapetti, Claudia; Gregory, Melissa K.; Whittall, Jonathan J.; Paton, James C.; McDevitt, Christopher A.

2018-01-01

Free fatty acids hold dual roles during infection, serving to modulate the host immune response while also functioning directly as antimicrobials. Of particular importance are the long chain polyunsaturated fatty acids, which are not commonly found in bacterial organisms, that have been proposed to have antibacterial roles. Arachidonic acid (AA) is a highly abundant long chain polyunsaturated fatty acid and we examined its effect upon Streptococcus pneumoniae. Here, we observed that in a murine model of S. pneumoniae infection the concentration of AA significantly increases in the blood. The impact of AA stress upon the pathogen was then assessed by a combination of biochemical, biophysical and microbiological assays. In vitro bacterial growth and intra-macrophage survival assays revealed that AA has detrimental effects on pneumococcal fitness. Subsequent analyses demonstrated that AA exerts antimicrobial activity via insertion into the pneumococcal membrane, although this did not increase the susceptibility of the bacterium to antibiotic, oxidative or metal ion stress. Transcriptomic profiling showed that AA treatment also resulted in a dramatic down-regulation of the genes involved in fatty acid biosynthesis, in addition to impacts on other metabolic processes, such as carbon-source utilization. Hence, these data reveal that AA has two distinct mechanisms of perturbing the pneumococcal membrane composition. Collectively, this work provides a molecular basis for the antimicrobial contribution of AA to combat pneumococcal infections. PMID:29867785

Effect of rate of pyrolysis on the textural properties of naturally-templated porous carbons from alginic acid.

PubMed

Marriott, Andrew S; Hunt, Andrew J; Bergström, Ed; Thomas-Oates, Jane; Clark, James H

2016-09-01

The effect of pyrolysis rate on the properties of alginic acid-derived carbonaceous materials, termed Starbon ® , was investigated. Thermal Gravimetry-IR was used to prepare porous carbons up to 800 °C at several rates and highlighted increased CO 2 production at higher pyrolysis rates. N 2 porosimetry of the resultant carbons shows how pyrolysis rate affects both the mesopore structure and thus surface area and surface energy. Surface capacity of these carbons was analysed by methylene blue dye adsorption. In general, as the rate of pyrolysis increased, the mesopore content and adsorbent capacity decreased. It is considered here that the rapid production of volatiles at these higher rates causes structural collapse of the non-templated pore network. The work here demonstrates that pyrolysis rate is a key variable which needs to be controlled to maximise the textural properties of Starbon ® required for adsorption applications.

Controlled release of Lactobacillus rhamnosus biofilm probiotics from alginate-locust bean gum microcapsules.

PubMed

Cheow, Wean Sin; Kiew, Tie Yi; Hadinoto, Kunn

2014-03-15

Chitosan-coated alginate microcapsules containing high-density biofilm Lactobacillus rhamnosus have been previously shown to exhibit higher freeze drying- and thermal-tolerance than their planktonic counterparts. However, their cell release profile remains poor due to the capsules' susceptibility to the gastric environment. Herein the effects of adding locust bean (LB) and xanthan (XT) gums to alginate (AGN) capsules on the stress tolerance and cell release profiles in simulated gastrointestinal fluids are investigated. Compared to the AGN-only capsules, the AGN-LB capsules exhibit improved stress tolerance (i.e. ≈ 6x for freeze drying, 100x for thermotolerance, 10x for acid), whereas the AGN-XT capsules only improve the acid tolerance. Importantly, the AGN-LB capsules possess the optimal cell release profile with a majority of cells released in the simulated intestinal juice than in the gastric juice. The AGN-LB capsules' superiority is attributed to their stronger interaction with the chitosan coating and high swelling capacity, thus delaying their bulk dissolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation, characterization, and in vitro release of gentamicin from coralline hydroxyapatite-alginate composite microspheres.

PubMed

Sivakumar, M; Rao, K Panduranga

2003-05-01

In this work, composite microspheres were prepared from bioactive ceramics such as coralline hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] granules, a biodegradable polymer, sodium alginate, and an antibiotic, gentamicin. Previously, we have shown a gentamicin release from coralline hydroxyapatite granules-chitosan composite microspheres. In the present investigation, we attempted to prepare composite microspheres containing coralline hydroxyapatite granules and sodium alginate by the dispersion polymerization technique with gentamicin incorporated by absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. Fourier transform infrared spectra clearly indicated the presence of per-acid of sodium alginate, phosphate, and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs showed that the composite microspheres were spherical in shape and porous in nature. The particle size of composite microspheres was analyzed, and the average size was found to be 15 microns. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns. Copyright 2003 Wiley Periodicals, Inc.

AaCAT1 of the Yellow Fever Mosquito, Aedes aegypti

PubMed Central

Hansen, Immo A.; Boudko, Dmitri Y.; Shiao, Shin-Hong; Voronov, Dmitri A.; Meleshkevitch, Ella A.; Drake, Lisa L.; Aguirre, Sarah E.; Fox, Jeffrey M.; Attardo, Geoffrey M.; Raikhel, Alexander S.

2011-01-01

Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to l-histidine at neutral pH (K0.5l-His = 0.34 ± 0.07 mm, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His+-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues. PMID:21262963

Interactions of collagen molecules in the presence of N-hydroxysuccinimide activated adipic acid (NHS-AA) as a crosslinking agent.

PubMed

Zhang, Min; Wu, Kun; Li, Guoying

2011-11-01

The effect of crosslinking agent on pepsin-soluble bovine collagen solution was examined using N-hydroxysuccinimide activated adipic acid (NHS-AA) as a crosslinker. Electrophoretic patterns indicated that crosslinks formed when NHS-AA was added. A higher polarity level deduced from the changes in the fluorescence emission spectrum of pyrene in the crosslinked collagen solution indicated that the formation of well-ordered aggregates was suppressed. The random aggregation of collagens was also observed by atomic force microscopy (AFM). Furthermore, the association of collagens into fibrils was influenced by crosslinking. Self-assembly was suppressed at 37°C; however, as temperature was increased to 39°C, a small amount of NHS-AA leaded to an improvement in the ability of self-aggregation. Although more random structure was brought about by crosslinking, self-aggregation might still be promoted as temperature was increased, accompanying by the thermal stability improvement of fibrils. Copyright © 2011 Elsevier B.V. All rights reserved.

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

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.

Influence of processing parameters on pore structure of 3D porous chitosan-alginate polyelectrolyte complex scaffolds.

PubMed

Florczyk, Stephen J; Kim, Dae-Joon; Wood, David L; Zhang, Miqin

2011-09-15

Fabrication of porous polymeric scaffolds with controlled structure can be challenging. In this study, we investigated the influence of key experimental parameters on the structures and mechanical properties of resultant porous chitosan-alginate (CA) polyelectrolyte complex (PEC) scaffolds, and on proliferation of MG-63 osteoblast-like cells, targeted at bone tissue engineering. We demonstrated that the porous structure is largely affected by the solution viscosity, which can be regulated by the acetic acid and alginate concentrations. We found that the CA PEC solutions with viscosity below 300 Pa.s yielded scaffolds of uniform pore structure and that more neutral pH promoted more complete complexation of chitosan and alginate, yielding stiffer scaffolds. CA PEC scaffolds produced from solutions with viscosities below 300 Pa.s also showed enhanced cell proliferation compared with other samples. By controlling the key experimental parameters identified in this study, CA PEC scaffolds of different structures can be made to suit various tissue engineering applications. Copyright © 2011 Wiley Periodicals, Inc.

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium

PubMed Central

Jalil, Aamir; Khan, Samiullah; Naeem, Fahad; Haider, Malik Suleman; Sarwar, Shoaib; Riaz, Amna; Ranjha, Nazar Muhammad

2017-01-01

Abstract In present investigation new formulations of Sodium Alginate/Acrylic acid hydrogels with high porous structure were synthesized by free radical polymerization technique for the controlled drug delivery of analgesic agent to colon. Many structural parameters like molecular weight between crosslinks (M c), crosslink density (M r), volume interaction parameter (v 2,s), Flory Huggins water interaction parameter and diffusion coefficient (Q) were calculated. Water uptake studies was conducted in different USP phosphate buffer solutions. All samples showed higher swelling ratio with increasing pH values because of ionization of carboxylic groups at higher pH values. Porosity and gel fraction of all the samples were calculated. New selected samples were loaded with the model drug (diclofenac potassium).The amount of drug loaded and released was determined and it was found that all the samples showed higher release of drug at higher pH values. Release of diclofenac potassium was found to be dependent on the ratio of sodium alginate/acrylic acid, EGDMA and pH of the medium. Experimental data was fitted to various model equations and corresponding parameters were calculated to study the release mechanism. The Structural, Morphological and Thermal Properties of interpenetrating hydrogels were studied by FTIR, XRD, DSC, and SEM. PMID:29491802

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium.

PubMed

Jalil, Aamir; Khan, Samiullah; Naeem, Fahad; Haider, Malik Suleman; Sarwar, Shoaib; Riaz, Amna; Ranjha, Nazar Muhammad

2017-01-01

In present investigation new formulations of Sodium Alginate/Acrylic acid hydrogels with high porous structure were synthesized by free radical polymerization technique for the controlled drug delivery of analgesic agent to colon. Many structural parameters like molecular weight between crosslinks ( M c ), crosslink density ( M r ), volume interaction parameter ( v 2, s ), Flory Huggins water interaction parameter and diffusion coefficient ( Q ) were calculated. Water uptake studies was conducted in different USP phosphate buffer solutions. All samples showed higher swelling ratio with increasing pH values because of ionization of carboxylic groups at higher pH values. Porosity and gel fraction of all the samples were calculated. New selected samples were loaded with the model drug (diclofenac potassium).The amount of drug loaded and released was determined and it was found that all the samples showed higher release of drug at higher pH values. Release of diclofenac potassium was found to be dependent on the ratio of sodium alginate/acrylic acid, EGDMA and pH of the medium. Experimental data was fitted to various model equations and corresponding parameters were calculated to study the release mechanism. The Structural, Morphological and Thermal Properties of interpenetrating hydrogels were studied by FTIR, XRD, DSC, and SEM.

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.

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

Alginate Particles as Platform for Drug Delivery by the Oral Route: State-of-the-Art.

PubMed

Sosnik, Alejandro

2014-01-01

Pharmaceutical research and development aims to design products with ensured safety, quality, and efficacy to treat disease. To make the process more rational, coherent, efficient, and cost-effective, the field of Pharmaceutical Materials Science has emerged as the systematic study of the physicochemical properties and behavior of materials of pharmaceutical interest in relation to product performance. The oral route is the most patient preferred for drug administration. The presence of a mucus layer that covers the entire gastrointestinal tract has been exploited to expand the use of the oral route by developing a mucoadhesive drug delivery system that showed a prolonged residence time. Alginic acid and sodium and potassium alginates have emerged as one of the most extensively explored mucoadhesive biomaterials owing to very good cytocompatibility and biocompatibility, biodegradation, sol-gel transition properties, and chemical versatility that make possible further modifications to tailor their properties. The present review overviews the most relevant applications of alginate microparticles and nanoparticles for drug administration by the oral route and discusses the perspectives of this biomaterial in the future.

Preparation and activity of bubbling-immobilized cellobiase within chitosan-alginate composite.

PubMed

Wang, Fang; Su, Rong-Xin; Qi, Wei; Zhang, Ming-Jia; He, Zhi-Min

2010-01-01

Cellobiase can hydrolyze cellobiose into glucose; it plays a key role in the process of cellulose hydrolysis by reducing the product inhibition. To reuse the enzyme and improve the economic value of cellulosic ethanol, cellobiase was immobilized using sodium alginate and chitosan as carriers by the bubbling method. The immobilization conditions were optimized as follows: enzyme loading of 100 U cellobiase/g carrier, 30 min immobilization, 3.5 wt% sodium alginate, 0.25 wt% chitosan, and 2 wt% calcium chloride. Compared to free enzyme, the immobilized cellobiase had a decreased apparent K(m) and the maximum activity at a lower pH, indicating its higher acidic and thermal stability. The immobilized cellobiase was further tested in the hydrolysis of cellobiose and various cellulosic substrates (microcrystalline cellulose, filter paper, and ammonia-pretreated corn cobs). Together with cellulases, the immobilized cellobiase converted the cellulosic substrates into glucose with the rate and extent similar to the free enzyme.

Investigation of Oral Preparation That Is Expected to Improve Medication Administration: Preparation and Evaluation of Oral Gelling Tablet Using Sodium Alginate.

PubMed

Ito, Ikumi; Ito, Akihiko; Unezaki, Sakae

2017-01-01

We investigated the preparation of a gelling tablet that swells and forms a gel upon absorbing water, and hence would be easy for patients to swallow. We prepared naked tablets and compressed coated tablets by the direct tableting or wet granule-compression methods, using the commonly prescribed drug acetaminophen (AA) and sodium alginate (AG) as a thickening agent. The tablets quickly absorbed water, had favorable gelling properties, low adhesiveness, appropriate drug dissolution profile, and at the same time, were easy to swallow. In the case of naked tablets, water absorption increased upon granulation, but gelling of AG interfere when AA and AG were present together. There was no change in the adhesiveness, and more than 30 min were required to achieve a 25% dissolution ratio. Compressed coated tablets that were made with AA in the inner layer and granulated AG in the outer layer showed improved dissolution behavior, it was about 90% dissolution ratio in 30 min, owing to the water absorption property of AG, and decreased adhesiveness. In this case, there was a difference in the outer layer thickness. As the outer layer amount increased, dissolution slowed, but it did not depend on the compression pressure. Our gelling tablet can be prepared by using AA (main drug) in the inner layer and an appropriate thickness of granulated AG in the outer layer of compressed coated tablets.

Formation and oral administration of alginate microspheres loaded with pDNA coding for lymphocystis disease virus (LCDV) to Japanese flounder.

PubMed

Tian, Ji-Yuan; Sun, Xiu-Qin; Chen, Xi-Guang

2008-05-01

Oral delivery of plasmid DNA (pDNA) is a desirable approach for fish immunization in intensive culture. However, its effectiveness is limited because of possible degradation of pDNA in the fish's digestive system. In this report, alginate microspheres loaded with pDNA coding for fish lymphocystis disease virus (LCDV) and green fluorescent protein were prepared with a modified oil containing water (W/O) emulsification method. Yield, loading percent and encapsulation efficiency of alginate microspheres were 90.5%, 1.8% and 92.7%, respectively. The alginate microspheres had diameters of less than 10 microm, and their shape was spherical. As compared to sodium alginate, a remarkable increase of DNA-phosphodiester and DNA-phosphomonoester bonds was observed for alginate microspheres loaded with pDNA by Fourier transform infrared (FTIR) spectroscopic analysis. Agarose gel electrophoresis showed a little supercoiled pDNA was transformed to open circular and linear pDNA during encapsulation. The cumulative release of pDNA in alginate microspheres was acidic media, and it was less than 6.5% in pH 9.0 alkaline media in 12h. RT-PCR and immunofluorescence imaging indicated that pDNA expressed RNA and green fluorescent protein in tissues of fish 10-90 days after oral administration. An indirect enzyme-linked immunosorbent assay (ELISA) showed that sera were positive (OD >or=0.3) for anti-LCDV antibody from week 3 to week 16 for fish orally vaccinated with alginate microspheres loaded with pDNA, in comparison with fish orally vaccinated with naked pDNA. Our results display that alginate microspheres obtained by W/O emulsification are promising carriers for oral delivery of pDNA. This encapsulation technique has the potential for DNA vaccine delivery applications due to its ease of operation, low cost and significant immune effect.

Application of hyaluronic acid/sodium alginate-based microparticles to prevent tissue adhesion in a rabbit model.

PubMed

Back, Ja Hoon; Cho, Wan Jin; Kim, Jun Ho; Park, Il Kyu; Kwon, Sung Won

2016-04-01

Postsurgical adhesion formation is a concern in every field of surgery. We evaluated the efficacy of hyaluronic acid/sodium alginate-based microparticle anti-adhesive agents (MP) for the prevention of postsurgical adhesion formation in a standardized rabbit model. To evaluate the anti-adhesion effect, a uterus-abdominal wall abrasion model was created in rabbits. On the surface of the injured uterus, an anti-adhesive agent, Interceed(®) or MP, was applied (positive control and study groups, respectively; n = 10 each). In another group of 10 animals, neither agent was applied (negative control group). The adhesion levels were graded 3 weeks after surgery. Acute and chronic toxicity was also evaluated. The grade of adhesion was significantly lower in the MP group than in the negative control and positive control groups. No evidence of acute or chronic toxicity induced by this material was found in blood and tissue analysis. MP shows potential as an effective novel type of resorbable biomaterial to reduce postoperative adhesion. The easy placement and handling of this material make the MP powder attractive as a tissue adhesion barrier.

Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.

PubMed

Baranek, Jakub; Kaznowski, Adam; Konecka, Edyta; Naimov, Samir

2015-09-01

Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

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

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.

Enhancement of neurite outgrowth in PC12 cells stimulated with cyclic AMP and NGF by 6-acylated ascorbic acid 2-O-alpha-glucosides (6-Acyl-AA-2G), novel lipophilic ascorbate derivatives.

PubMed

Zhou, Xiaohua; Tai, Akihiro; Yamamoto, Itaru

2003-03-01

It has been shown that ascorbate (AsA) and its stable derivative, ascorbic acid 2-O-alpha-glucoside (AA-2G), do not elicit neurite outgrowth in PC12 cells. However, these ascorbates are synergistically enhanced by both dibutyryl cyclic AMP (Bt(2)cAMP)- and nerve growth factor (NGF)-induced neurite outgrowth in this model. In the present study, the effects of a series of novel lipophilic ascorbate derivatives, 6-acylated ascorbic acid 2-O-alpha-glucosides (6-Acyl-AA-2G), on neurite outgrowth induced by Bt(2)cAMP and NGF were examined in PC12 cells. We found that all the tested acylated ascorbate derivatives enhanced neurite formation induced by both agents in a dose-dependent manner. Of the 6-Acyl-AA-2G derivatives, 6-octanoyl ascorbic acid 2-O-alpha-glucoside (6-Octa-AA-2G) enhanced the Bt(2)cAMP-induced phosphorylated MAPK p44 and p42 expression. A alpha-glucosidase inhibitor, castanospermine, completely abrogated the promotion of neurite outgrowth and MAPK expression by 6-Octa-AA-2G. Addition of 6-Octa-AA-2G (0.5 mM) to PC12 cells caused a rapid and significant increase in intracellular AsA content, which reached a maximum and was maintained from 12 to 24 h after the culture. These findings suggest that 6-Acyl-AA-2G is rapidly hydrolyzed to AsA within the cell and enhances neurite differentiation through the interaction with the inducer-activated MAPK pathway.

Synthesis and in vitro characterization of a novel S-protected thiolated alginate.

PubMed

Hauptstein, Sabine; Dezorzi, Stefanie; Prüfert, Felix; Matuszczak, Barbara; Bernkop-Schnürch, Andreas

2015-06-25

The object of this study was to synthesize and characterize a novel S-protected thiolated polymer with a high degree of modification. In this regard, an alginate-cysteine and an alginate-cysteine-2-mercaptonicotinic acid conjugate were synthesized. To achieve a high coupling rate of the thiol group bearing ligand cysteine to the polymer, the carbohydrate was activated by an oxidative ring opening with sodium periodate followed by a reductive amination to bind the primary amino group of cysteine to resulting reactive aldehyde groups. The obtained thiolated polymer displayed 1561±130μmol thiol groups per gram polymer. About one third of these thiol groups were S-protected by the implementation of a thiol bearing aromatic protection group via disulfide bond formation. Test tablets of both modified polymers showed improved stability against oxidation in aqueous environment compared to the unmodified alginate and exhibit higher water-uptake capacity. Rheological investigations revealed an increased viscosity of the S-protected thiolated polymer whereat the thiolated non S-protected polymer showed gelling properties after the addition of hydrogen peroxide. The mucoadhesive properties could be improved significantly for both derivatives and no alteration in biocompatibility tested on Caco-2 cell monolayer employing an MTT assay could be detected after modification. According to these results, both new derivatives seem promising for various applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation of the chitosan/poly(glutamic acid)/alginate polyelectrolyte complexing hydrogel and study on its drug releasing property.

PubMed

Chen, Yu; Yan, Xiaoting; Zhao, Jian; Feng, Huaiyu; Li, Puwang; Tong, Zongrui; Yang, Ziming; Li, Sidong; Yang, Jueying; Jin, Shaohua

2018-07-01

In the current study, a novel semi-dissolution/acidification/sol-gel transition (SD-A-SGT) method was explored for the preparation of polyelectrolyte complexing (PEC) composite hydrogels with natural polymers only. A chitosan (CS) powder was uniformly dispersed in a solution of poly(glutamic acid) (PGA) and alginate (SA) to form a semi-dissolved slurry mixture that was then exposed to an gaseous acidic atmosphere. CS was gradually dissolved and interacted with PGA and SA to form a CS/PGA/SA PEC composite hydrogel with a homogeneous structure. The SD-A-SGT procedure was able to overcome the shortcomings of direct mixing method via the PEC interaction. The effects of the hydrogel composition on its structure and properties were investigated by FTIR, XRD, rheology study, XPS, SEM, and swelling kinetics. The drug delivery performance of the CS/PGA/SA hydrogel was explored using piroxicam (PXC) as a model drug. PXC was in situ embedded in the hydrogel by the SD-A-SGT method. The hydrogel exhibited pH responsive drug release behaviors that were affected by the hydrogel composition. In all, the SD-A-SGT method for preparing PEC composite hydrogels has a great application potential in constructing the CS based hydrogels as medical materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Systemic AA amyloidosis in the red fox (Vulpes vulpes).

PubMed

Rising, Anna; Cederlund, Ella; Palmberg, Carina; Uhlhorn, Henrik; Gaunitz, Stefan; Nordling, Kerstin; Ågren, Erik; Ihse, Elisabet; Westermark, Gunilla T; Tjernberg, Lars; Jörnvall, Hans; Johansson, Jan; Westermark, Per

2017-11-01

Amyloid A (AA) amyloidosis occurs spontaneously in many mammals and birds, but the prevalence varies considerably among different species, and even among subgroups of the same species. The Blue fox and the Gray fox seem to be resistant to the development of AA amyloidosis, while Island foxes have a high prevalence of the disease. Herein, we report on the identification of AA amyloidosis in the Red fox (Vulpes vulpes). Edman degradation and tandem MS analysis of proteolyzed amyloid protein revealed that the amyloid partly was composed of full-length SAA. Its amino acid sequence was determined and found to consist of 111 amino acid residues. Based on inter-species sequence comparisons we found four residue exchanges (Ser31, Lys63, Leu71, Lys72) between the Red and Blue fox SAAs. Lys63 seems unique to the Red fox SAA. We found no obvious explanation to how these exchanges might correlate with the reported differences in SAA amyloidogenicity. Furthermore, in contrast to fibrils from many other mammalian species, the isolated amyloid fibrils from Red fox did not seed AA amyloidosis in a mouse model. © 2017 The Protein Society.

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.

In vitro fermentation and prebiotic potential of novel low molecular weight polysaccharides derived from agar and alginate seaweeds.

PubMed

Ramnani, Priya; Chitarrari, Roberto; Tuohy, Kieran; Grant, John; Hotchkiss, Sarah; Philp, Kevin; Campbell, Ross; Gill, Chris; Rowland, Ian

2012-02-01

Fermentation properties and prebiotic potential of novel low molecular weight polysaccharides (LMWPs) derived from agar and alginate bearing seaweeds was investigated. Ten LMWPs were supplemented to pH, temperature controlled anaerobic batch cultures inoculated with human feces from three donors, in triplicate. Microbiota changes were monitored using Fluorescent in-situ hybridization and short chain fatty acids, the fermentation end products were analysed using gas chromatography. Of the ten LMWPs tested, Gelidium seaweed CC2253 of molecular weight 64.64 KDa showed a significant increase in bifidobacterial populations from log(10) 8.06 at 0 h to log(10) 8.55 at 24 h (p = 0.018). For total bacterial populations, alginate powder CC2238 produced a significant increase from log(10) 9.01 at 0 h to log(10) 9.58 at 24 h (p = 0.032). No changes were observed in the other bacterial groups tested viz. Bacteroides, Lactobacilli/Enterococci, Eubacterium rectale/Clostridium coccoides and Clostridium histolyticum. The polysaccharides also showed significant increases in total SCFA production, particularly acetic and propionic acids, indicating that they were readily fermented. In conclusion, some LMWPs derived from agar and alginate bearing seaweeds were fermented by gut bacteria and exhibited potential to be used a novel source of prebiotics. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

Structural, physicochemical and antioxidant properties of sodium alginate isolated from a Tunisian brown seaweed.

PubMed

Sellimi, Sabrine; Younes, Islem; Ayed, Hanen Ben; Maalej, Hana; Montero, Veronique; Rinaudo, Marguerite; Dahia, Mostefa; Mechichi, Tahar; Hajji, Mohamed; Nasri, Moncef

2015-01-01

An original sodium alginate from Tunisian seaweed (Cystoseira barbata) was purified and characterized by circular dichroism (CD) and ATR-FTIR spectroscopies. ATR-FTIR spectrum of C. barbata sodium alginate (CBSA) showed the characteristic bands of mannuronic (M) and guluronic acids (G). The M/G ratio was estimated by CD (M/G = 0.59) indicating that CBSA was composed of 37% mannuronic acid and 63% guluronic acid. The analysis of viscosity of CBSA showed evidence of pseudoplastic fluid behaviour. The emulsifying capacity of CBSA was evaluated at different concentrations (0.25-3%), temperatures (25-100 °C) and pH (3.0-11.0). Compared to most commercial emulsifiers, the emulsion formulated by CBSA was found to be less sensitive to temperature changes and more stable at acidic pH. CBSA was examined for antioxidant properties using various antioxidant assays. CBSA exhibited important DPPH radical-scavenging activity (74% inhibition at a concentration of 0.5 mg/ml) and considerable ferric reducing potential. Effective hydroxyl-radical scavenging activity (82% at a concentration of 5 mg/ml) and potent protection activity against DNA breakage were also recorded for CBSA. However, in the linoleate-β-carotene system, CBSA exerted moderate antioxidant activity (60% at a concentration of 1.5 mg/ml). Therefore, CBSA can be used as a natural ingredient in food industry or in the pharmaceutical field. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

A Controlled Drug-Delivery Experiment Using Alginate Beads

ERIC Educational Resources Information Center

Farrell, Stephanie; Vernengo, Jennifer

2012-01-01

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

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

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.

Preparation and characterization of electrospun alginate/PLA nanofibers as tissue engineering material by emulsion eletrospinning.

PubMed

Xu, Weihong; Shen, Renzhe; Yan, Yurong; Gao, Jie

2017-01-01

Scaffolds made by biomaterials offer favorite environment for cell grow and show a wide potential application in tissue engineering. Novel biocompatibility materials polylatic acid (PLA) nanofiber membranes with favorable biocompatibility and good mechanical strength could serve as an innovative tissue engineering scaffold. Sodium alginate (SA) could be used in biomedical areas because of its anti-bacterial property, hydrophilicity and biocompatibility. In this article, we chose PLA as continuous phase and SA as dispersion phase to prepare a W/O emulsion and then electrospun it to get a SA/PLA composite nanofiber membranes. The CLSM images illustrated that the existence of SA was located on the surface of composite fibers and the FTIR results confirmed the result. A calcium ion replacement step was used as an after-treatment for SA/PLA nanofiber membranes in order to anchor the alginic ion in a form of gelated calcium alginate (CA). The single fiber tensile test shows a good mechanical property of CA/PLA nanofiber membranes, and the nanofiber membranes are beneficial for cell proliferation and differentiation owing to MTT array as well as Alizarin red S (ARS) staining test. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel pH-responsive hydrogel-based on calcium alginate engineered by the previous formation of polyelectrolyte complexes (PECs) intended to vaginal administration.

PubMed

Ferreira, Natália Noronha; Perez, Taciane Alvarenga; Pedreiro, Liliane Neves; Prezotti, Fabíola Garavello; Boni, Fernanda Isadora; Cardoso, Valéria Maria de Oliveira; Venâncio, Tiago; Gremião, Maria Palmira Daflon

2017-10-01

This work aimed to develop a calcium alginate hydrogel as a pH responsive delivery system for polymyxin B (PMX) sustained-release through the vaginal route. Two samples of sodium alginate from different suppliers were characterized. The molecular weight and M/G ratio determined were, approximately, 107 KDa and 1.93 for alginate_S and 32 KDa and 1.36 for alginate_V. Polymer rheological investigations were further performed through the preparation of hydrogels. Alginate_V was selected for subsequent incorporation of PMX due to the acquisition of pseudoplastic viscous system able to acquiring a differential structure in simulated vaginal microenvironment (pH 4.5). The PMX-loaded hydrogel (hydrogel_PMX) was engineered based on polyelectrolyte complexes (PECs) formation between alginate and PMX followed by crosslinking with calcium chloride. This system exhibited a morphology with variable pore sizes, ranging from 100 to 200 μm and adequate syringeability. The hydrogel liquid uptake ability in an acid environment was minimized by the previous PECs formation. In vitro tests evidenced the hydrogels mucoadhesiveness. PMX release was pH-dependent and the system was able to sustain the release up to 6 days. A burst release was observed at pH 7.4 and drug release was driven by an anomalous transport, as determined by the Korsmeyer-Peppas model. At pH 4.5, drug release correlated with Weibull model and drug transport was driven by Fickian diffusion. The calcium alginate hydrogels engineered by the previous formation of PECs showed to be a promising platform for sustained release of cationic drugs through vaginal administration.

Oyster mushroom’s lipase enzyme entrapment on calcium alginate as biocatalyst in the synthesis of lauryl diethanolamide

NASA Astrophysics Data System (ADS)

Wijayati, N.; Masubah, K.; Supartono

2017-02-01

Lipase is an enzyme with large biotechnology applications, such as hydrolysis in the food industry, applications in chemical industry, synthesis of polymers and surfactants. Lipase was isolated from oyster mushroom with activity 0,93 U/mg and protein content 1,1234 mg/mL. Lipase was immobilized by entrapment method in a matrix of Ca-alginate. This report describes that we have developed for the synthesis of lauryl diethanolamide The result showed that the optimum condition of lipase immobilization was achieved on 3% Na-alginate solution with protein content 0,84 mg/mL and the activity 3,33 U/mg. An amide (22.911%) formed from the amidation of lauric acid and diethanolamine.

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.

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

Phospholipid sources for adrenic acid mobilization in RAW 264.7 macrophages. Comparison with arachidonic acid.

PubMed

Guijas, Carlos; Astudillo, Alma M; Gil-de-Gómez, Luis; Rubio, Julio M; Balboa, María A; Balsinde, Jesús

2012-11-01

Cells metabolize arachidonic acid (AA) to adrenic acid (AdA) via 2-carbon elongation reactions. Like AA, AdA can be converted into multiple oxygenated metabolites, with important roles in various physiological and pathophysiological processes. However, in contrast to AA, there is virtually no information on how the cells regulate the availability of free AdA for conversion into bioactive products. We have used a comparative lipidomic approach with both gas chromatography and liquid chromatography coupled to mass spectrometry to characterize changes in the levels of AA- and AdA-containing phospholipid species in RAW 264.7 macrophage-like cells. Incubation of the cells with AA results in an extensive conversion to AdA but both fatty acids do not compete with each other for esterification into phospholipids. AdA but not AA, shows preference for incorporation into phospholipids containing stearic acid at the sn-1 position. After stimulation of the cells with zymosan, both AA and AdA are released in large quantities, albeit AA is released to a greater extent. Finally, a variety of phosphatidylcholine and phosphatidylinositol molecular species contribute to AA; however, AdA is liberated exclusively from phosphatidylcholine species. Collectively, these results identify significant differences in the cellular utilization of AA and AdA by the macrophages, suggesting non-redundant biological actions for these two fatty acids. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

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.

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

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.

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

PubMed

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

2015-07-10

Brown algal polysaccharides such as alginate, polymers of uronic acids, and laminaran, beta-1,3 and 1,6-glucan, can be fermented by human intestinal microbiota. To evaluate the effects of these polysaccharides on infections caused by food poisoning pathogens, we investigated the adhesion and invasion of pathogens (Salmonella Typhimurium, Listeria monocytogenes and Vibrio parahaemolyticus) in human enterocyte-like HT-29-Luc cells and in infections caused in BALB/c mice. Both sodium Na-alginate and laminaran (0.1% each) inhibited the adhesion of the pathogens to HT-29-Luc cells by approximately 70-90%. The invasion of S. Typhimurium was also inhibited by approximately 70 and 80% by Na-alginate and laminaran, respectively. We observed that incubation with Na-alginate for 18 h increased the transepithelial electrical resistance of HT-29-Luc monolayer cells. Four days after inoculation with 7 log CFU/mouse of S. Typhimurium, the faecal pathogen count in mice that were not fed polysaccharides (control mice) was about 6.5 log CFU/g while the count in mice that were fed Na-alginate had decreased to 5.0 log CFU/g. The liver pathogen count, which was 4.1 log CFU/g in the control mice, was also decreased in mice that were fed Na-alginate. In contrast, the mice that were fed laminaran exhibited a more severe infection than that exhibited by control mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Alginate biopolymer as green corrosion inhibitor for copper in 1 M hydrochloric acid: Experimental and theoretical approaches

NASA Astrophysics Data System (ADS)

Jmiai, A.; El Ibrahimi, B.; Tara, A.; El Issami, S.; Jbara, O.; Bazzi, L.

2018-04-01

The anti-corrosion behavior of sodium alginate (SA) on copper in the 1 M hydrochloric medium was carried out using weight loss and electrochemical measurements. The obtained results show that the inhibition increases with SA concentration and then reaches a maximum of 83% at a concentration of 0.1 mg L-1. The effect of temperature on the reactions of copper corrosion inhibition and analyzing the thermodynamic parameters revealed that the mode of adsorption has a physical nature and obeys the Langmuir isotherm. The surface morphology was performed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry and atomic force microscopy. To better understand the adsorption mechanism, describing the relationship between inhibitory ability and the molecular structure of SA, quantum calculations using density functional theory were performed. Monte Carlo simulation approache was performed to know well of the relationship between the inhibition ability and molecular structure of alginate.

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.

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.

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.

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

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.

Production of 5'-phosphodiesterase by Catharanthus roseus cells promoted by heat-degraded products generated from uronic acid.

PubMed

Akimoto-Tomiyama, Chiharu; Aoyagi, Hideki; Ozawa, Tetsuo; Tanaka, Hideo

2002-01-01

Polyalginate was autoclaved at 121 degrees C for 20 min and its molecular weight distribution was analyzed. The autoclaved alginate yielded alginate polymer, oligomer and heat degraded products (HDPs). Each of the separated substances promoted 5'-phosphodiesterase (5'-PDase) production in suspension culture of Catharanthus roseus cells. HDPs could also be generated from other uronic acids (galacturonic acid and glucuronic acid) by autoclave treatment. The most effective substance in the HDPs was isolated and characterized as trans-4,5-dihydroxy-2-cyclopenten-1-one (DHCP). The optimal conditions for DHCP production were also established (autoclaving 1 mg/ml monogalacturonic acid [pH 2] at 121 degrees C for 2 h). A combination of oligo-alginate (below 4 kDa) and HDPs significantly promoted the production of 5'-PDase in C. roseus. Based on the above results, a novel alginate complex that gave a 44-fold increase in 5'-PDase production by C. roseus was developed.

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.

Synthesis of ST7612AA1, a Novel Oral HDAC Inhibitor, via Radical 
Thioacetic Acid Addition.

PubMed

Battistuzzi, Gianfranco; Giannini, Giuseppe

2016-12-01

In the expanding field of anticancer drugs, HDAC inhibitors are playing an increasingly important role. To date, four/five HDAC inhibitors have been approved by FDA. All these compounds fit the widely accepted HDAC inhibitors pharmacophore model characterized by a cap group, a linker chain and a zinc binding group (ZBG), able to bind the Zn 2+ ion in a pocket of the HDAC active site. Romidepsin, a natural compound, is the only thiol derivative. We have selected a new class of synthetic HDAC inhibitors, the thio-ω(lactam-carboxamide) derivatives, with ST7612AA1 as drug candidate, pan-inhibitor active in the range of single- to two-digit nanomolar concentrations. Preliminary results of a synthetic optimization attempt towards a fast scale-up process are here proposed. In the four steps of synthesis, from unsaturated amino acid intermediate to the final product, we explored different synthetic conditions in order to have a transferable process for a scale-up synthetic laboratory. In the first step, isobutyl chloroformate was used and, after a simple work up with 1M HCl, 2 (96% yield) was obtained as a white solid, which was used directly in the next step. For thioacetic acid addition to the double bond of intermediate 2 , two different routes were possible, with addition reaction in the first (D') or last step (D). Reactions of 2 to give 5 or of 4 to give ST7612AA1 were both performed in dioxane. Reactions were fast and did not need the usually advised radical quenching with cyclohexene. The corresponding products were obtained in good yields (step D', 89%; step D, 81%) after a flash chromatography. , a thiol derivative prodrug of ST7464AA1 , is the first of a new generation of HDAC inhibitors, very potent, orally administered, and well tolerated. Here, we have identified a synthetic route, competitive, versatile and easily transferable to industrial processes.

The 9aaTAD Transactivation Domains: From Gal4 to p53.

PubMed

Piskacek, Martin; Havelka, Marek; Rezacova, Martina; Knight, Andrea

2016-01-01

The family of the Nine amino acid Transactivation Domain, 9aaTAD family, comprises currently over 40 members. The 9aaTAD domains are universally recognized by the transcriptional machinery from yeast to man. We had identified the 9aaTAD domains in the p53, Msn2, Pdr1 and B42 activators by our prediction algorithm. In this study, their competence to activate transcription as small peptides was proven. Not surprisingly, we elicited immense 9aaTAD divergence in hundreds of identified orthologs and numerous examples of the 9aaTAD species' convergence. We found unforeseen similarity of the mammalian p53 with yeast Gal4 9aaTAD domains. Furthermore, we identified artificial 9aaTAD domains generated accidentally by others. From an evolutionary perspective, the observed easiness to generate 9aaTAD transactivation domains indicates the natural advantage for spontaneous generation of transcription factors from DNA binding precursors.

Effect of the Microstructure on Diffusion Bonded AA5083, AA6082 and AA7075 Aluminium Alloys

NASA Astrophysics Data System (ADS)

Venugopal, S.; Mahendran, G.

2018-05-01

Rolled plates of aluminium alloys AA5083, AA6082 and AA7075 of 5 mm thickness are joined by diffusion bonding at varied parameters. The microstructure evolution of AA5083, AA6082 and AA7075 aluminium alloys is characterized by Transmission Electron Microscopy (TEM). Metallurgical investigations and mechanical tests are also performed to correlate the results of the TEM investigations with the mechanical properties of the produced diffusion bonded joints. It is observed that the bonding and shear strength of the alloys increase with the increase in bonding temperature, due to the diffusion of micro-constituents in the interface. High temperature enhances the uniform distribution of secondary phase particles and reduces pore formation/defects in the bonded joints.

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).

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).

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.

Modeling the controllable pH-responsive swelling and pore size of networked alginate based biomaterials.

PubMed

Chan, Ariel W; Neufeld, Ronald J

2009-10-01

Semisynthetic network alginate polymer (SNAP), synthesized by acetalization of linear alginate with di-aldehyde, is a pH-responsive tetrafunctionally linked 3D gel network, and has potential application in oral delivery of protein therapeutics and active biologicals, and as tissue bioscaffold for regenerative medicine. A constitutive polyelectrolyte gel model based on non-Gaussian polymer elasticity, Flory-Huggins liquid lattice theory, and non-ideal Donnan membrane equilibria was derived, to describe SNAP gel swelling in dilute and ionic solutions containing uni-univalent, uni-bivalent, bi-univalent or bi-bi-valent electrolyte solutions. Flory-Huggins interaction parameters as a function of ionic strength and characteristic ratio of alginates of various molecular weights were determined experimentally to numerically predict SNAP hydrogel swelling. SNAP hydrogel swells pronouncedly to 1000 times in dilute solution, compared to its compact polymer volume, while behaving as a neutral polymer with limited swelling in high ionic strength or low pH solutions. The derived model accurately describes the pH-responsive swelling of SNAP hydrogel in acid and alkaline solutions of wide range of ionic strength. The pore sizes of the synthesized SNAP hydrogels of various crosslink densities were estimated from the derived model to be in the range of 30-450 nm which were comparable to that measured by thermoporometry, and diffusion of bovine serum albumin. The derived equilibrium swelling model can characterize hydrogel structure such as molecular weight between crosslinks and crosslinking density, or can be used as predictive model for swelling, pore size and mechanical properties if gel structural information is known, and can potentially be applied to other point-link network polyelectrolytes such as hyaluronic acid gel.

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.

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

Alginate Beads Containing Lactase: Stability and Microstructure.

PubMed

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

2017-06-12

β-Galactosidase (lactase) is a widely used enzyme in the food industry; however, it has low stability against thermal and mechanical treatments. Due to this, the purpose of the present research was to analyze the encapsulation of lactase in alginate-Ca(II) beads in order to maintain its enzymatic activity toward freezing, freezing/thawing, and storage. Also, the effect of the addition of trehalose, and arabic and guar gums and their influence on the microstructure as well as on thermal properties and molecular mobility were studied. Lactase was successfully encapsulated in alginate-Ca(II) beads, and the inclusion of trehalose was critical for activity preservation toward treatments, being improved in guar gum-containing systems. The gums increased the T m ' values, which represents a valuable technological improvement. Finally, the presence of secondary excipients affected the microstructure, showing rods with smaller outer diameter and with lower compactness than alginate-Ca(II) beads. Also, bead composition greatly affects the size, shape, and relaxation times.

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

NASA Astrophysics Data System (ADS)

Tam, Susan Kimberly

Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

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.

Alginate and DNA Gels Are Suitable Delivery Systems for Diabetic Wound Healing.

PubMed

Tellechea, Ana; Silva, Eduardo A; Min, Jianghong; Leal, Ermelindo C; Auster, Michael E; Pradhan-Nabzdyk, Leena; Shih, William; Mooney, David J; Veves, Aristidis

2015-06-01

Diabetic foot ulcers (DFU) represent a severe health problem and an unmet clinical challenge. In this study, we tested the efficacy of novel biomaterials in improving wound healing in mouse models of diabetes mellitus (DM). The biomaterials are composed of alginate- and deoxyribonucleic acid (DNA)-based gels that allow incorporation of effector cells, such as outgrowth endothelial cells (OEC), and provide sustained release of bioactive factors, such as neuropeptides and growth factors, which have been previously validated in experimental models of DM wound healing or hind limb ischemia. We tested these biomaterials in mice and demonstrate that they are biocompatible and can be injected into the wound margins without major adverse effects. In addition, we show that the combination of OEC and the neuropeptide Substance P has a better healing outcome than the delivery of OEC alone, while subtherapeutic doses of vascular endothelial growth factor (VEGF) are required for the transplanted cells to exert their beneficial effects in wound healing. In summary, alginate and DNA scaffolds could serve as potential delivery systems for the next-generation DFU therapies. © The Author(s) 2015.

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.

Controlling the size of alginate gel beads by use of a high electrostatic potential.

PubMed

Klokk, T I; Melvik, J E

2002-01-01

The effect of several parameters on the size of alginate beads produced by use of an electrostatic potential bead generator was examined. Parameters studied included needle diameter, electrostatic potential, alginate solution flow rate, gelling ion concentration and alginate concentration and viscosity, as well as alginate composition. Bead size was found to decrease with increasing electrostatic potential, but only down to a certain level. Minimum bead size was reached at between 2-4 kV/cm for the needles tested. The smallest alginate beads produced (using a needle with inner diameter 0.18 mm) had a mean diameter of approximately 300 microm. Bead size was also found to be dependent upon the flow rate of the fed alginate solution. Increasing the gelling ion concentration resulted in a moderate decrease in bead size. The concentration and viscosity of the alginate solution also had an effect on bead size as demonstrated by an increased bead diameter when the concentration or viscosity was increased. This effect was primarily an effect of the viscosity properties of the solution, which led to changes in the rate of droplet formation in the bead generator. Lowering the flow rate of the alginate solution could partly compensate for the increase in bead size with increased viscosity. For a constant droplet size, alginates with a low G block content (F(GG) approximately 0.20) resulted in approximately 30% smaller beads than alginates with a high G block content (F(GG) approximately 0.60). This is explained as a result of differences in the shrinking properties of the beads.

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.

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.

Bacterial cellulose based hydrogel (BC-g-AA) and preliminary result of swelling behavior

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

Hakam, Adil; Lazim, Azwan Mat; Abdul Rahman, I. Irman

2013-11-27

In this study, hydrogel based on Bacterial cellulose (BC) or local known as Nata de Coco, which grafted with monomer: Acrylic acid (AA) is synthesis by using gamma radiation technique. These hydrogel (BC-g-AA) has unique characteristic whereby responsive to pH buffer solution.

Effect of Dietary L-ascorbic Acid (L-AA) on Production Performance, Egg Quality Traits and Fertility in Japanese Quail (Coturnix japonica) at Low Ambient Temperature.

PubMed

Shit, N; Singh, R P; Sastry, K V H; Agarwal, R; Singh, R; Pandey, N K; Mohan, J

2012-07-01

Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly (p<0.01) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail.

Polyelectrolyte capsules preloaded with interconnected alginate matrix: An effective capsule system for encapsulation and release of macromolecules.

PubMed

Sundaramurthy, Anandhakumar; Sundramoorthy, Ashok K

2018-02-01

In recent years, the design of stimuli-responsive hollow polymeric capsules is of tremendous interest for the scientific community because of the broad application of these capsules in the biomedical field. The use of weak polyelectrolytes as layer components for capsule fabrication is especially interesting as it results in hollow capsules that show unique release characteristics under physiological conditions. In this work, a methodology to prepare sub-micron sized alginate doped calcium carbonate (CaCO 3 ) particles through controlled precipitation in the presence of alginate is reported. Hollow capsules obtained by Layer-by-Layer (LbL) assembly of poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) are showing an interconnected alginate matrix in the interior of the capsules. Investigations showed that the presence of alginate matrix enhances the encapsulation of cationic molecules (e.g. doxorubicin hydrochloride) manifold by charge controlled attraction mechanism. Capsule permeability investigated by confocal laser scanning microscopy revealed that the transformation from an open state to closed state is accompanied by an intermediate state where capsules are neither open nor closed. Furthermore, time dependent study indicated that the encapsulation process is linear as a function of time. The cell viability experiments demonstrated excellent biocompatibility of hollow capsules with mouse embryonic fibroblast cells. Anticancer investigations showed that DOX loaded capsules have significant anti-proliferative characteristics against HeLa cells. Such capsules have high potential for use as drug carrier for cationic drugs in cancer therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

3D porous calcium-alginate scaffolds cell culture system improved human osteoblast cell clusters for cell therapy.

PubMed

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

2015-01-01

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

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.

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.

Fabrication of large size alginate beads for three-dimensional cell-cluster culture

NASA Astrophysics Data System (ADS)

Zhang, Zhengtao; Ruan, Meilin; Liu, Hongni; Cao, Yiping; He, Rongxiang

2017-08-01

We fabricated large size alginate beads using a simple microfluidic device under a co-axial injection regime. This device was made by PDMS casting with a mold formed by small diameter metal and polytetrafluorothylene tubes. Droplets of 2% sodium alginate were generated in soybean oil through the device and then cross-linked in a 2% CaCl2 solution, which was mixed tween80 with at a concentration of 0.4 to 40% (w/v). Our results showed that the morphology of the produced alginate beads strongly depends on the tween80 concentration. With the increase of concentration of tween80, the shape of the alginate beads varied from semi-spherical to tailed-spherical, due to the decrease of interface tension between oil and cross-link solution. To access the biocompatibility of the approach, MCF-7 cells were cultured with the alginate beads, showing the formation of cancer cells clusters which might be useful for future studies.

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.

Asiatic Acid (AA) Sensitizes Multidrug-Resistant Human Lung Adenocarcinoma A549/DDP Cells to Cisplatin (DDP) via Downregulation of P-Glycoprotein (MDR1) and Its Targets.

PubMed

Cheng, Qilai; Liao, Meixiang; Hu, Haibo; Li, Hongliang; Wu, Longhuo

2018-01-01

P-glycoprotein (P-gp, i.e., MDR1) is associated with the phenotype of multidrug resistance (MDR) and causes chemotherapy failure in the management of cancers. Searching for effective MDR modulators and combining them with anticancer drugs is a promising strategy against MDR. Asiatic acid (AA), a natural triterpene isolated from the plant Centella asiatica, may have an antitumor activity. The present study assessed the reversing effect of AA on MDR and possible molecular mechanisms of AA action in MDR1-overexpressing cisplatin (DDP)-resistant lung cancer cells, A549/DDP. Human lung adenocarcinoma A549/DDP cells were either exposed to different concentrations of AA or treated with DDP, and their viability was measured by the MTT assay. A Rhodamine 123 efflux assay, immunofluorescent staining, ATPase assay, reverse-transcription PCR (RT-PCR), and western blot analysis were conducted to elucidate the mechanisms of action of AA on MDR. Our results showed that AA significantly enhanced the cytotoxicity of DDP toward A549/DDP cells but not its parental A549 cells. Furthermore, AA strongly inhibited P-gp expression by blocking MDR1 gene transcription and increased the intracellular accumulation of the P-gp substrate Rhodamine 123 in A549/DDP cells. Nuclear factor (NF)-kB (p65) activity, IkB degradation, and NF-kB/p65 nuclear translocation were markedly inhibited by pretreatment with AA. Additionally, AA inhibited the MAPK-ERK pathway, as indicated by decreased phosphorylation of ERK1 and -2, AKT, p38, and JNK, thus resulting in reduced activity of the Y-box binding protein 1 (YB1) via blockage of its nuclear translocation. AA reversed P-gp-mediated MDR by inhibition of P-gp expression. This effect was likely related to downregulation of YB1, and this effect was mediated by the NF-kB and MAPK-ERK pathways. AA may be useful as an MDR reversal agent for combination therapy in clinical trials. © 2018 The Author(s). Published by S. Karger AG, Basel.

Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

PubMed Central

Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

2008-01-01

AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

Cryoprotective roles of trehalose and alginate oligosaccharides during frozen storage of peeled shrimp (Litopenaeus vannamei).

PubMed

Zhang, Bin; Wu, Hai-Xiao; Yang, Hui-Cheng; Xiang, Xing-Wei; Li, Hai-Bo; Deng, Shang-Gui

2017-08-01

Cryoprotective saccharides are widely accepted additives that reduce thawing loss, maintain texture, and retard protein denaturation in the frozen seafood. The present study aimed to investigate the roles of trehalose and alginate oligosaccharides on cryoprotection of frozen shrimp, primarily focusing on the interactions between myosin and saccharide molecules using a molecular dynamics (MD) simulation analysis. The results indicated that soaking in the trehalose and alginate oligosaccharides solutions markedly reduced thawing and cooking losses in frozen shrimp, with respective values decreasing to 6.02%, 8.14%, and 5.99%, 8.19% after 9weeks of storage, which were significantly lower than that of fresh water treatment (9.75% and 15.09%). Our assumption was that water replacement played a leading role in cryoprotection, as shown in previous experimental results and reports. Furthermore, homology modeling and MD simulations confirmed that trehalose and alginate oligosaccharides substituted the water molecules around the myosin surface by forming hydrogen bonds with polar residues of amino acids, thereby stabilizing the structures in the absence of water during frozen storage. These conditions affected the flexibility of particular amino acid residues, enhanced the residue cross correlations within the two chains of myosin, and also increased the total interaction energy between myosin and water/saccharide molecules, thereby leading to an increase in protein stability. Finally, by comparing the experimental results to that of MD simulation, significant positive correlation existed between saccharides and the stabilization of myosin in shrimp muscle. The findings of the present study may help better understand the cryoprotective mechanisms of saccharides in frozen shrimp, and the two saccharides may be potentially used as alternative additives in seafood to maintain better quality during frozen storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Coupled adsorption-photocatalytic degradation of crystal violet under sunlight using chemically synthesized grafted sodium alginate/ZnO/graphene oxide composite.

PubMed

Mohamed, S K; Hegazy, Sh H; Abdelwahab, N A; Ramadan, A M

2018-03-01

This research aimed to synthesize natural polymer nanocomposite and employ it for coupled adsorption- photocatalytic degradation of crystal violet. Sodium alginate-g-poly (acrylic acid-co-cinnamic acid) and its composites with ZnO nanorods and graphene oxide sheets were synthesized and characterized using FT-IR, XRD, SEM, HR-TEM and DR/UV-vis spectroscopy. The adsorption efficiency of samples for crystal violet has been studied in the dark. The effect of different parameters as pH, initial dye concentration, contact time and temperature on the adsorption efficiency of the synthesized sample has been examined. Kinetics studies showed that the adsorption of all samples was well described by the pseudo-second-order model and the equilibrium adsorption results fitted Freundlich model. The maximum adsorption capacity achieved at pH 5.0 was 13.85 mg g -1 . Thermodynamic studies exhibited that the adsorption is spontaneous, endothermic in nature and leads to higher entropy. Coupled adsorption-photocatalytic degradation studies under sunlight showed an enhancement in the removal efficiency by 10%. In the case of sodium alginate-g-poly (acrylic acid-co-cinnamic acid)/ZnO/graphene oxide composite, the removal efficiency after 5 h under sunlight was 94% versus 84% in the dark. Copyright © 2017 Elsevier B.V. All rights reserved.

Multifunctional slow-release organic-inorganic compound fertilizer.

PubMed

Ni, Boli; Liu, Mingzhu; Lü, Shaoyu; Xie, Lihua; Wang, Yanfang

2010-12-08

Multifunctional slow-release organic-inorganic compound fertilizer (MSOF) has been investigated to improve fertilizer use efficiency and reduce environmental pollution derived from fertilizer overdosage. The special fertilizer is based on natural attapulgite (APT) clay used as a matrix, sodium alginate used as an inner coating and sodium alginate-g-poly(acrylic acid-co-acrylamide)/humic acid (SA-g-P(AA-co-AM)/HA) superabsorbent polymer used as an outer coating. The coated multielement compound fertilizer granules were produced in a pan granulator, and the diameter of the prills was in the range of 2.5-3.5 mm. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nutrients release, were examined. In addition, a mathematical model for nutrient release from the fertilizer was applied to calculate the diffusion coefficient D of nutrients in MSOF. The degradation of the SA-g-P(AA-co-AM)/HA coating was assessed by examining the weight loss with incubation time in soil. It is demonstrated that the product prepared by a simple route with good slow-release property may be expected to have wide potential applications in modern agriculture and horticulture.

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

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.

40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

Code of Federal Regulations, 2013 CFR

2013-07-01

... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to...

40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

Code of Federal Regulations, 2012 CFR

2012-07-01

... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to...

40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

Code of Federal Regulations, 2011 CFR

2011-07-01

... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to...

High surface area mesoporous activated carbon-alginate beads for efficient removal of methylene blue.

PubMed

Nasrullah, Asma; Bhat, A H; Naeem, Abdul; Isa, Mohamed Hasnain; Danish, Mohammed

2018-02-01

High surface area mesoporous activated carbon-alginate (AC-alginate) beads were successfully synthesized by entrapping activated carbon powder derived from Mangosteen fruit peel into calcium-alginate beads for methylene blue (MB) removal from aqueous solution. The structure and surface characteristics of AC-alginate beads were analyzed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and surface area analysis (S BET ), while thermal properties were tested using thermogravimetric analysis (TGA). The effect of AC-alginate dose, pH of solution, contact time, initial concentration of MB solution and temperature on MB removal was elucidated. The results showed that the maximum adsorption capacity of 230mg/g was achieved for 100mg/L of MB solution at pH 9.5 and temperature 25°C. Furthermore, the adsorption of MB on AC-alginate beads followed well pseudo-second order equation and equilibrium adsorption data were better fitted by the Freundlich isotherm model. The findings reveal the feasibility of AC-alginate beads composite to be used as a potential and low cost adsorbent for removal of cationic dyes. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-03-01

Synthesis and structural characterization of hydrogels composed of sodium alginate, polyethylene oxide and acrylic acid with cyclodextrin as the hydrocolloid prepared at different pH values is presented. The hydrogels synthesized show significant variations in rheological properties, drug encapsulation capability and release kinetics. The hydrogels prepared at lower pH (pH 1) are more elastic, have high tensile strength and remain almost unaffected by varying temperature or frequency. Further, their Ibuprofen encapsulation capacity is low and releases it slowly. The hydrogel prepared at neutral pH (pH 7) is viscoelastic, thermo-reversible and also exhibits sol-gel transition on applying frequency and changing temperature. It shows highest Ibuprofen encapsulation capacity and also optimum drug release kinetics. The hydrogel prepared at higher pH (pH 12) is more viscous, has low tensile strength, is unstable to change in temperature and has fast drug release rate. The study highlights the pH responsiveness of three composite alginate hydrogels prepared under different conditions to be employed in drug delivery applications. Copyright © 2015 Elsevier B.V. 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.

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.

Targeting fatty acid amide hydrolase and transient receptor potential vanilloid-1 simultaneously to modulate colonic motility and visceral sensation in the mouse: A pharmacological intervention with N-arachidonoyl-serotonin (AA-5-HT).

PubMed

Bashashati, M; Fichna, J; Piscitelli, F; Capasso, R; Izzo, A A; Sibaev, A; Timmermans, J-P; Cenac, N; Vergnolle, N; Di Marzo, V; Storr, M

2017-12-01

Endocannabinoid anandamide (AEA) inhibits intestinal motility and visceral pain, but it may also be proalgesic through transient receptor potential vanilloid-1 (TRPV1). AEA is degraded by fatty acid amide hydrolase (FAAH). This study explored whether dual inhibition of FAAH and TRPV1 reduces diarrhea and abdominal pain. Immunostaining was performed on myenteric plexus of the mouse colon. The effects of the dual FAAH/TRPV1 inhibitor AA-5-HT on electrically induced contractility, excitatory junction potential (EJP) and fast (f) and slow (s) inhibitory junction potentials (IJP) in the mouse colon, colonic propulsion and visceromotor response (VMR) to rectal distension were studied. The colonic levels of endocannabinoids and fatty acid amides were measured. CB1-positive neurons exhibited TRPV1; only some TRPV1 positive neurons did not express CB1. CB1 and FAAH did not colocalize. AA-5-HT (100 nM-10 μM) decreased colonic contractility by ~60%; this effect was abolished by TRPV1 antagonist 5'-IRTX, but not by CB1 antagonist, SR141716. AA-5-HT (1 μM-10 μM) inhibited EJP by ~30% and IJPs by ~50%. The effects of AA-5-HT on junction potentials were reversed by SR141716 and 5`-IRTX. AA-5-HT (20 mg/kg; i.p.) inhibited colonic propulsion by ~30%; SR141716 but not 5`-IRTX reversed this effect. AA-5-HT decreased VMR by ~50%-60%; these effects were not blocked by SR141716 or 5`-IRTX. AA-5-HT increased AEA in the colon. The effects of AA-5-HT on visceral sensation and colonic motility are differentially mediated by CB1, TRPV1 and non-CB1/TRPV1 mechanisms, possibly reflecting the distinct neuromodulatory roles of endocannabinoid and endovanilloid FAAH substrates in the mouse intestine. © 2017 John Wiley & Sons Ltd.

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.

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

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.

Assessment of alginate hydrogel degradation in biological tissue using viscosity-sensitive fluorescent dyes

NASA Astrophysics Data System (ADS)

Shkand, Tatiana V.; Chizh, Mykola O.; Sleta, Iryna V.; Sandomirsky, Borys P.; Tatarets, Anatoliy L.; Patsenker, Leonid D.

2016-12-01

The main goal of this study is to investigate a combination of viscosity-sensitive and viscosity-insensitive fluorescent dyes to distinguish different rheological states of hydrogel based biostructural materials and carriers in biological tissues and to assess their corresponding location areas. The research is done in the example of alginate hydrogel stained with viscosity-sensitive dyes Seta-470 and Seta-560 as well as the viscosity-insensitive dye Seta-650. These dyes absorb/emit at 469/518, 565/591 and 651/670 nm, respectively. The rheological state of the alginate, the area of the fluorescence signal and the mass of the dense alginate versus the calcium gluconate concentration utilized for alginate gelation were studied in vitro. The most pronounced change in the fluorescence signal area was found at the same concentrations of calcium gluconate (below ~1%) as the change in the alginate plaque mass. The stained alginate was also implanted in situ in rat hip and myocardium and monitored using fluorescence imaging. In summary, our data indicate that the viscosity sensitive dye in combination with the viscosity-insensitive dye allow tracking the biodegradation of the alginate hydrogel and determining the rheological state of hydrogel in biological tissue, which both should have relevance for research and clinical applications. Using this method we estimated the half-life of the dense alginate hydrogel in a rat hip to be in the order of 4 d and about 6-8 d in rat myocardium. The half-life of the dense hydrogel in the myocardium was found to be long enough to prevent aneurysm rupture of the left ventricle wall, one of the more severe complications of the early post-infarction period.

Physical, mechanical, and barrier properties of sodium alginate/gelatin emulsion based-films incorporated with canola oil

NASA Astrophysics Data System (ADS)

Syarifuddin, A.; Hasmiyani; Dirpan, A.; Mahendradatta, M.

2017-12-01

The development of mixed emulsion-based films formed by sodium alginate/gelatin incorporated with canola oil can offer particular properties such as water vapor barrier properties. The different ratios of sodium alginate/gelatin and sodium alginate/gelatin emulsion-based films incorporated with canola oil were developed and their effects on films’ physical, mechanical and barrier properties were assessed. Here we set out to examine whether canola oil addition and different ratio of sodium alginate/gelatin modified physical, mechanical, and barrier properties of films. To do so, the films were prepared by vary the ratio of sodium alginate/gelatin (2.5, 1, 0.5). Canola oil addition induced changes in moisture content, thickness, solubility, water vapor transmission rate (WVTR), percent elongation at break (p<0.05). In addition, it is apparent that varying ratio of sodium alginate to gelatin induced change the mechanical properties of films. The reduction of sodium alginate to gelatin decreased the tensile strength of both films. Improved values of WVTR, tensile strength and solubility at break were observed when the ratio of sodium alginate/gelatin emulsion film incorporated with canola oil was 2.5. Therefore, different ratio of sodium alginate/gelatin incorporated with canola oil can be used to tailor emulsion films with enhanced water vapor barrier and mechanical properties.

Variations in chondrogenesis of human bone marrow-derived mesenchymal stem cells in fibrin/alginate blended hydrogels

PubMed Central

Ma, Kun; Titan, Ashley L.; Stafford, Melissa; Zheng, Chun hua; Levenston, Marc E.

2012-01-01

Fibrin and alginate hydrogels have been widely used to support chondrogenesis of bone marrow-derived mesenchymal stem cells (BM-MSCs) for articular cartilage and fibrocartilage tissue engineering, with distinct advantages and disadvantages to each material. Attempting to produce a gel scaffold exhibiting beneficial characteristics of both materials, we fabricated fibrin/alginate blended hydrogels at various blend ratios and evaluated the gel morphology, mechanical properties and their support for BM-MSC chondrogenesis. Results show that when the fibrin/alginate ratio decreased, the fibrin architecture transitioned from uniform to interconnected fibrous and finally to disconnected islands against an alginate background, with opposing trends in the alginate architecture. Fibrin maintained gel extensibility and promoted cell proliferation, while alginate improved the gel biostability and better supported glycosaminoglycan and collagen II production and chondrogenic gene expression. Blended gels had physical and biological characteristics intermediate between fibrin and alginate. Of the blends examined, FA 40:8 (40 mg/mL fibrinogen blended with 8 mg/mL alginate) was found to be the most appropriate group for future studies on tension-driven BM-MSC fibrochondrogenesis. As BM-MSC differentiation appeared to vary between fibrin and alginate regions of blended scaffolds, this study also highlighted the potential to develop spatially heterogeneous tissues through manipulating the heterogeneity of scaffold composition. PMID:22750738

Fabrication of patterned calcium cross-linked alginate hydrogel films and coatings through reductive cation exchange.

PubMed

Bruchet, Marion; Melman, Artem

2015-10-20

Calcium cross-linked alginate hydrogels are widely used in targeted drug delivery, tissue engineering, wound treatment, and other biomedical applications. We developed a method for preparing homogeneous alginate hydrogels cross-linked with Ca(2+) cations using reductive cation exchange in homogeneous iron(III) cross-linked alginate hydrogels. Treatment of iron(III) cross-linked alginate hydrogels with calcium salts and sodium ascorbate results in reduction of iron(III) cations to iron(II) that are instantaneously replaced with Ca(2+) cations, producing homogeneous ionically cross-linking hydrogels. Alternatively, the cation exchange can be performed by photochemical reduction in the presence of calcium chloride using a sacrificial photoreductant. This approach allows fabrication of patterned calcium alginate hydrogels through photochemical patterning of iron(III) cross-linked alginate hydrogel followed by the photochemical reductive exchange of iron cations to calcium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Halloysite nanotubes as carriers of vancomycin in alginate-based wound dressing.

PubMed

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

2017-09-01

The influence of an inorganic support - halloysite nanotubes - on the release rate and biological activity of the antibiotic encapsulated in alginate-based dressings was studied. The halloysite samples were loaded with approx. 10 wt.% of the antibiotic and then encapsulated in Alginate and Gelatin/Alginate gels. The material functionalized with aliphatic amine significantly extended the release of vancomycin from alginate-based gels as compared to that achieved when silica was used. After 24 h, the released amounts of the antibiotic immobilized at silica reached 70%, while for the drug immobilized at halloysite the released amount of vancomycin reached 44% for Alginate discs. The addition of gelatin resulted in even more prolonged sustained release of the drug. The antibiotic was released from the system with a double barrier with Higuchi kinetic model and Fickian diffusion mechanism. Only the immobilized drug encapsulated in Alginate gel demonstrated very good antimicrobial activity against various bacteria. The inhibition zones were greater than those of the standard discs for the staphylococci and enterococci bacteria tested. The addition of gelatin adversely affected the biological activity of the system. The inhibition zones were smaller than those of the reference samples. A reduction in the drug dose by half had no significant effect on changing the release rate and microbiological activity. The in vivo toxicity studies of the material with immobilized drug were carried out with Acutodesmus acuminatus and Daphnia magna . The material studied had no effect on the living organisms used in the bioassays. The proposed system with a double barrier demonstrated high storage stability.

Inhibition of free radical-induced erythrocyte hemolysis by 2-O-substituted ascorbic acid derivatives.

PubMed

Takebayashi, Jun; Kaji, Hiroaki; Ichiyama, Kenji; Makino, Kazutaka; Gohda, Eiichi; Yamamoto, Itaru; Tai, Akihiro

2007-10-15

Inhibitory effects of 2-O-substituted ascorbic acid derivatives, ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S), on 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of sheep erythrocytes were studied and were compared with those of ascorbic acid (AA) and other antioxidants. The order of the inhibition efficiency was AA-2S> or =Trolox=uric acid> or =AA-2P> or =AA-2G=AA>glutathione. Although the reactivity of the AA derivatives against AAPH-derived peroxyl radical (ROO(*)) was much lower than that of AA, the derivatives exerted equal or more potent protective effects on AAPH-induced hemolysis and membrane protein oxidation. In addition, the AA derivatives were found to react per se with ROO(*), not via AA as an intermediate. These findings suggest that secondary reactions between the AA derivative radical and ROO(*) play a part in hemolysis inhibition. Delayed addition of the AA derivatives after AAPH-induced oxidation of erythrocytes had already proceeded showed weaker inhibition of hemolysis compared to that of AA. These results suggest that the AA derivatives per se act as biologically effective antioxidants under moderate oxidative stress and that AA-2G and AA-2P may be able to act under severe oxidative stress after enzymatic conversion to AA in vivo.

Propylisopropylacetic acid (PIA), a constitutional isomer of valproic acid, uncompetitively inhibits arachidonic acid acylation by rat acyl-CoA synthetase 4: a potential drug for bipolar disorder

PubMed Central

Modi, Hiren R.; Basselin, Mireille; Taha, Ameer Y.; Li, Lei O.; Coleman, Rosalind A.; Bialer, Meir; Rapoport, Stanley I.

2013-01-01

Background Mood stabilizers used for treating bipolar disorder (BD) selectively downregulate arachidonic acid (AA) turnover (deacylation-reacylation) in brain phospholipids, when given chronically to rats. In vitro studies suggest that one of these, valproic acid (VPA), which is teratogenic, reduces AA turnover by inhibiting the brain acyl-CoA synthetase (Acsl)-4 mediated acylation of AA to AA-CoA. We tested whether non-teratogenic VPA analogues might also inhibit Acsl-4 catalyzed acylation, and thus have potential anti-BD action. Methods Rat Acsl4-flag protein was expressed in E. coli, and the ability of three VPA analogues, propylisopropylacetic acid (PIA), propylisopropylacetamide (PID) and N-methyl-2,2,3,3-tetramethylcyclopropanecarboxamide (MTMCD), and of sodium butyrate, to inhibit conversion of AA to AA-CoA by Acsl4 was quantified using Michaelis-Menten kinetics. Results Acsl4-mediated conversion of AA to AA-CoA in vitro was inhibited uncompetitively by PIA, with a Ki of 11.4 mM compared to a published Ki of 25 mM for VPA, while PID, MTMCD and sodium butyrate had no inhibitory effect. Conclusions PIA's ability to inhibit conversion of AA to AA-CoA by Acsl4 in vitro suggests that, like VPA, PIA may reduce AA turnover in brain phospholipids in unanesthetized rats, and if so, may be effective as a non-teratogenic mood stabilizer in BD patients. PMID:23354024

Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses.

PubMed

Larosa, Claudio; Salerno, Marco; de Lima, Juliana Silva; Merijs Meri, Remo; da Silva, Milena Fernandes; de Carvalho, Luiz Bezerra; Converti, Attilio

2018-08-01

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices. Copyright © 2018 Elsevier B.V. All rights reserved.

Digital microfluidic three-dimensional cell culture and chemical screening platform using alginate hydrogels

PubMed Central

2015-01-01

Electro wetting-on-dielectric (EWOD) digital microfluidics (DMF) can be used to develop improved chemical screening platforms using 3-dimensional (3D) cell culture. Alginate hydrogels are one common method by which a 3D cell culture environment is created. This paper presents a study of alginate gelation on EWOD DMF and investigates designs to obtain uniform alginate hydrogels that can be repeatedly addressed by any desired liquids. A design which allows for gels to be retained in place during liquid delivery and removal without using any physical barriers or hydrophilic patterning of substrates is presented. A proof of concept screening platform is demonstrated by examining the effects of different concentrations of a test chemical on 3D cells in alginate hydrogels. In addition, the temporal effects of the various chemical concentrations on different hydrogel posts are demonstrated, thereby establishing the benefits of an EWOD DMF 3D cell culture and chemical screening platform using alginate hydrogels. PMID:25945142

Effects of alpha lipoic acid, ascorbic acid-6-palmitate, and fish oil on the glutathione, malonaldehyde, and fatty acids levels in erythrocytes of streptozotocin induced diabetic male rats.

PubMed

Yilmaz, Okkeş; Ozkan, Yusuf; Yildirim, Mehmet; Oztürk, A Ihsan; Erşan, Yasemin

2002-01-01

In this research, it has been aimed to evaluate the improvement effects of alpha lipoic acid (ALA), ascorbic acid-6-palmitate (AA6P), fish oil (FO), and their combination (COM) on some biochemical properties in erythrocytes of streptozotocin (STZ)-induced diabetic male rats. According to experimental results, glutathione (GSH) level in erythrocytes decreased in diabetes (P < 0.01), D + ALA, and D + AA6P groups (P < 0.001). Malonaldehyde (MA) level increased in diabetes (P < 0.05), D + FO, and D + COM groups (P < 0.001), but its level in D + AA6P and D + ALA groups was lower in diabetes group (P < 0.01). Total lipid level in diabetes and diabetes plus antioxidant administered groups were higher than control. Total cholesterol level was high in diabetes and D + ALA groups (P < 0.05), but its level reduced in D + FO compared to control and diabetes groups, P < 0.05, < 0.001, respectively. Total triglyceride (TTG) level was high in the D + ALA (P < 0.05) and D + COM (P < 0.001) groups. In contrast, TTG level in blood of diabetes group was higher than diabetes plus antioxidant and FO administered groups (P < 0.001). According to gas chromatography analysis results, while the palmitic acid raised in diabetes group (P < 0.05), stearic acid in D + FO, D + ALA, and diabetes groups was lower than control (P < 0.05), oleic acid reduced in D + COM and D + FO groups, but its level raised in D + AA6P and D + ALA groups (P < 0.01). As the linoleic acid (LA) elevated in ALA + D, D + AA6P, and diabetes groups, linolenic acid level in diabetes, D + AA6P, and D + FO groups was lower than control (P < 0.001). Arachidonic acid (AA) decreased in D + ALA, D+ AA6P, and diabetes groups (P < 0.01), but its level in D + COM and D + FO was higher than control (P < 0.05). Docosahexaenoic acid (DHA) increased in D + AA6P and D + COM (P < 0.05). While the total saturated fatty acid level raised in diabetes group, its level reduced in D + ALA and D + FO groups (P < 0.05). In contrast, total

Effects of alginate on frozen-thawed boar spermatozoa quality, lipid peroxidation and antioxidant enzymes activities.

PubMed

Hu, Jinghua; Geng, Guoxia; Li, Qingwang; Sun, Xiuzhu; Cao, Hualin; Liu, Yawei

2014-06-30

Although alginate was reported to play an important role as free radical scavengers in vitro and could be used as sources of natural antioxidants, there was no study about the cryoprotective effects of alginate on boar spermatozoa freezing. The objective of this research was to evaluate the effects of different concentrations of alginate added to the freezing extenders on boar spermatozoa motility, plasma membrane integrity, acrosomal integrity, mitochondrial activities, lipid peroxidation and antioxidative enzymes activities (SOD and GSH-Px) after thawing. Alginate was added to the TCG extender to yield six different final concentrations: 0, 0.2, 0.4, 0.6, 0.8, and 1.0mg/mL. The semen extender supplemented with various doses of alginate increased (P<0.05) total motility. The spermatozoa plasma membrane integrity and mitochondrial activity were improved at four different concentrations: 0.4, 0.6, 0.8, 1.0mg/mL. The addition of alginate also provided significantly positive effect on post-thaw boar spermatozoa acrosomal integrity at concentrations of 0.6, 0.8, 1.0mg/mL, compared with that of the control (P<0.05). The freezing extenders with the presence of alginate led to higher SOD and GSH-Px activities and lower MDA levels, in comparison to the control (P<0.05). In summary, alginate exhibited a dose-related response on frozen-thawed boar spermatozoa motility, functional integrity and antioxidative capacity at appropriate concentrations. Therefore alginate could be employed as an effective cryoprotectant in boar spermatozoa cryopreservation. Copyright © 2014 Elsevier B.V. All rights reserved.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

PubMed

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Development of a Spirulina Extract/Alginate-Imbedded PCL Nanofibrous Cosmetic Patch.

PubMed

Byeon, Seon Yeong; Cho, Myung Kwon; Shim, Kyou Hee; Kim, Hye Jin; Song, Hyeon Gi; Shin, Hwa Sung

2017-09-28

Cosmetic patches have recently been developed as skin products for personal care owing to rapid advances in the technology of delivery of active ingredients, moisture, and adhesiveness to skin. Alginate and Spirulina are typical marine resources used in cosmetic products. This research involved the development of a Spirulina extract-impregnated alginate nanofiber cosmetic patch supported by a polycaprolactone (PCL) nanofiber cover ( Spi /Alg-PCL NF patch). In addition to the ability of alginate to affect moisture and adhesiveness to skin, the impregnation of Spirulina extract strengthened those abilities as well as its own bioactive effectiveness. All fabrication processing steps were undertaken in aqueous solution. The three components (alginate, Spirulina extract, and PCL) had no detected cytotoxicity in human keratinocyte cell-based examination. In addition, wetting the pre-dried patch on the skin resulted in the Spirulina extract being released within 30 min. The results indicate the excellence of the Spi /Alg-PCL NF patch as a skin-care cosmetic device.

Oxygen-dependent regulation of c-di-GMP synthesis by SadC controls alginate production in Pseudomonas aeruginosa.

PubMed

Schmidt, Annika; Hammerbacher, Anna Silke; Bastian, Mike; Nieken, Karen Jule; Klockgether, Jens; Merighi, Massimo; Lapouge, Karine; Poschgan, Claudia; Kölle, Julia; Acharya, K Ravi; Ulrich, Martina; Tümmler, Burkhard; Unden, Gottfried; Kaever, Volkhard; Lory, Stephen; Haas, Dieter; Schwarz, Sandra; Döring, Gerd

2016-10-01

Pseudomonas aeruginosa produces increased levels of alginate in response to oxygen-deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis-induced alginate production by planktonic PAO1 requires the diguanylate cyclase (DGC) SadC, previously identified as a regulator of surface-associated lifestyles. Furthermore, we found that the gene products of PA4330 and PA4331, located in a predicted operon with sadC, have a major impact on alginate production: deletion of PA4330 (odaA, for oxygen-dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA4331 (odaI, for oxygen-dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA, which did not significantly affect DGC activity of SadC, OdaI inhibited c-di-GMP production by SadC. Our data indicate that SadC, OdaA and OdaI are components of a novel response pathway of P. aeruginosa that regulates alginate synthesis in an oxygen-dependent manner. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

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

PubMed

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

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

Copper-releasing, boron-containing bioactive glass-based scaffolds coated with alginate for bone tissue engineering.

PubMed

Erol, M M; Mouriňo, V; Newby, P; Chatzistavrou, X; Roether, J A; Hupa, L; Boccaccini, Aldo R

2012-02-01

The aim of this study was to synthesize and characterize new boron-containing bioactive glass-based scaffolds coated with alginate cross-linked with copper ions. A recently developed bioactive glass powder with nominal composition (wt.%) 65 SiO2, 15 CaO, 18.4 Na2O, 0.1 MgO and 1.5 B2O3 was fabricated as porous scaffolds by the foam replica method. Scaffolds were alginate coated by dipping them in alginate solution. Scanning electron microscopy investigations indicated that the alginate effectively attached on the surface of the three-dimensional scaffolds leading to a homogeneous coating. It was confirmed that the scaffold structure remained amorphous after the sintering process and that the alginate coating improved the scaffold bioactivity and mechanical properties. Copper release studies showed that the alginate-coated scaffolds allowed controlled release of copper ions. The novel copper-releasing composite scaffolds represent promising candidates for bone regeneration. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Reduction of volatile acidity of acidic wines by immobilized Saccharomyces cerevisiae cells.

PubMed

Vilela, A; Schuller, D; Mendes-Faia, A; Côrte-Real, M

2013-06-01

Excessive volatile acidity in wines is a major problem and is still prevalent because available solutions are nevertheless unsatisfactory, namely, blending the filter-sterilized acidic wine with other wines of lower volatile acidity or using reverse osmosis. We have previously explored the use of an empirical biological deacidification procedure to lower the acetic acid content of wines. This winemaker's enological practice, which consists in refermentation associated with acetic acid consumption by yeasts, is performed by mixing the acidic wine with freshly crushed grapes, musts, or marc from a finished wine fermentation. We have shown that the commercial strain Saccharomyces cerevisiae S26 is able to decrease the volatile acidity of acidic wines with a volatile acidity higher than 1.44 g L(-1) acetic acid, with no detrimental impact on wine aroma. In this study, we aimed to optimize the immobilization of S26 cells in alginate beads for the bioreduction of volatile acidity of acidic wines. We found that S26 cells immobilized in double-layer alginate-chitosan beads could reduce the volatile acidity of an acidic wine (1.1 g L(-1) acetic acid, 12.5 % (v/v) ethanol, pH 3.12) by 28 and 62 % within 72 and 168 h, respectively, associated with a slight decrease in ethanol concentration (0.7 %). Similar volatile acidity removal efficiencies were obtained in medium with high glucose concentration (20 % w/v), indicating that this process may also be useful in the deacidification of grape musts. We, therefore, show that immobilized S. cerevisiae S26 cells in double-layer beads are an efficient alternative to improve the quality of wines with excessive volatile acidity.

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

PubMed

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

2015-01-06

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

Alginate/sodium caseinate aqueous-core capsules: a pH-responsive matrix.

PubMed

Ben Messaoud, Ghazi; Sánchez-González, Laura; Jacquot, Adrien; Probst, Laurent; Desobry, Stéphane

2015-02-15

Alginate capsules have several applications. Their functionality depends considerably on their permeability, chemical and mechanical stability. Consequently, the creation of composite system by addition of further components is expected to control mechanical and release properties of alginate capsules. Alginate and alginate-sodium caseinate composite liquid-core capsules were prepared by a simple extrusion. The influence of the preparation pH and sodium caseinate concentration on capsules physico-chemical properties was investigated. Results showed that sodium caseinate influenced significantly capsules properties. As regards to the membrane mechanical stability, composite capsules prepared at pH below the isoelectric point of sodium caseinate exhibited the highest surface Young's modulus, increasing with protein content, explained by potential electrostatic interactions between sodium caseinate amino-groups and alginate carboxylic group. The kinetic of cochineal red A release changed significantly for composite capsules and showed a pH-responsive release. Sodium caseinate-dye mixture studied by absorbance and fluorescence spectroscopy confirmed complex formation at pH 2 by electrostatic interactions between sodium caseinate tryptophan residues and cochineal red sulfonate-groups. Consequently, the release mechanism was explained by membrane adsorption process. This global approach is useful to control release mechanism from macro and micro-capsules by incorporating guest molecules which can interact with the entrapped molecule under specific conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Oxidative potential of ambient water-soluble PM2.5 in the southeastern United States: contrasts in sources and health associations between ascorbic acid (AA) and dithiothreitol (DTT) assays

NASA Astrophysics Data System (ADS)

Fang, Ting; Verma, Vishal; Bates, Josephine T.; Abrams, Joseph; Klein, Mitchel; Strickland, Matthew J.; Sarnat, Stefanie E.; Chang, Howard H.; Mulholland, James A.; Tolbert, Paige E.; Russell, Armistead G.; Weber, Rodney J.

2016-03-01

The ability of certain components of particulate matter to induce oxidative stress through the generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and report here the development of a similar semi-automated system for the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed for a host of aerosol species, along with AA and DTT activities. We present a detailed contrast in findings from these two assays. Water-soluble AA activity was higher in summer and fall than in winter, with highest levels near heavily trafficked highways, whereas DTT activity was higher in winter compared to summer and fall and more spatially homogeneous. AA activity was nearly exclusively correlated with water-soluble Cu (r = 0.70-0.94 at most sites), whereas DTT activity was correlated with organic and metal species. Source apportionment models, positive matrix factorization (PMF) and a chemical mass balance method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from traffic emissions and secondary processes (e.g., organic aerosol oxidation or metals mobilization by secondary acids) to both AA and DTT activities in urban Atlanta. In contrast, biomass burning was a large source for DTT activity, but insignificant for AA. AA activity was not correlated with PM2.5 mass, while DTT activity co-varied strongly with mass (r = 0.49-0.86 across sites and seasons). Various linear models were developed to estimate AA and DTT activities for the central Atlanta Jefferson Street site, based on the CMB-E sources. The models were then used to estimate daily

Mesenchymal stem cells and alginate microcarriers for craniofacial bone tissue engineering: A review.

PubMed

Saltz, Adam; Kandalam, Umadevi

2016-05-01

Craniofacial bone is a complex structure with an intricate anatomical and physiological architecture. The defects that exist in this region therefore require a precise control of osteogenesis in their reconstruction. Unlike traditional surgical intervention, tissue engineering techniques mediate bone development with limited postoperative risk and cost. Alginate stands as the premier polymer in bone repair because of its mild ionotropic gelation and excellent biocompatibility, biodegradability, and injectability. Alginate microcarriers are candidates of choice to mediate cells and accommodate into 3-D environment. Several studies reported the use of alginate microcarriers for delivering cells, drugs, and growth factors. This review will explore the potential use of alginate microcarrier for stem cell systems and its application in craniofacial bone tissue engineering. © 2016 Wiley Periodicals, Inc.

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

NASA Astrophysics Data System (ADS)

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

2012-08-01

Microspheres, small spherical (polymeric) particles with or without second phase materials embedded or encapsulated, are important for many biomedical applications such as drug delivery and organ printing. Scale-up fabrication with the ability to precisely control the microsphere size and morphology has always been of great manufacturing interest. The objective of this work is to experimentally study the performance differences of bipolar and tripolar excitation waveforms in using drop-on-demand (DOD)-based single nozzle jetting for alginate microsphere fabrication. The fabrication performance has been evaluated based on the formability of alginate microspheres as a function of materials properties (sodium alginate and calcium chloride concentrations) and operating conditions. The operating conditions for each excitation include voltage rise/fall times, dwell times and excitation voltage amplitudes. Overall, the bipolar excitation is more robust in making spherical, monodispersed alginate microspheres as good microspheres for its wide working range of material properties and operating conditions, especially during the fabrication of highly viscous materials such as the 2% sodium alginate solution. For both bipolar and tripolar excitations, the sodium alginate concentration and the voltage dwell times should be carefully selected to achieve good microsphere formability.

Associations With Eicosapentaenoic Acid to Arachidonic Acid Ratio and Mortality in Hospitalized Heart Failure Patients.

PubMed

Watanabe, Shunsuke; Yoshihisa, Akiomi; Kanno, Yuki; Takiguchi, Mai; Yokokawa, Tetsuro; Sato, Akihiko; Miura, Shunsuke; Shimizu, Takeshi; Abe, Satoshi; Sato, Takamasa; Suzuki, Satoshi; Oikawa, Masayoshi; Sakamoto, Nobuo; Yamaki, Takayoshi; Sugimoto, Koichi; Kunii, Hiroyuki; Nakazato, Kazuhiko; Suzuki, Hitoshi; Saitoh, Shu-Ichi; Takeishi, Yasuchika

2016-12-01

Intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) lowers the risk of atherosclerotic cardiovascular events, particularly ischemic heart disease. In addition, the ratio of eicosapentaenoic acid (EPA; n-3 PUFA) to arachidonic acid (AA; n-6 PUFA) has recently been recognized as a risk marker of cardiovascular disease. In contrast, the prognostic impact of the EPA/AA ratio on patients with heart failure (HF) remains unclear. A total of 577 consecutive patients admitted for HF were divided into 2 groups based on median of the EPA/AA ratio: low EPA/AA (EPA/AA <0.32 mg/dl, n = 291) and high EPA/AA (EPA/AA ≥0.32, n = 286) groups. We compared laboratory data and echocardiographic findings and followed cardiac mortality. Although body mass index, blood pressure, B-type natriuretic peptide, hemoglobin, estimated glomerular filtration rate, total protein, albumin, sodium, C-reactive protein, and left ventricular ejection fraction did not differ between the 2 groups, cardiac mortality was significantly higher in the low EPA/AA group than in the high EPA/AA group (12.7 vs 5.9%, log-rank P = .004). Multivariate Cox proportional hazard analysis revealed that the EPA/AA ratio was an independent predictor of cardiac mortality (hazard ratio 0.677, 95% confidence interval 0.453-0.983, P = .041) in patients with HF. The EPA/AA ratio was an independent predictor of cardiac mortality in patients with HF; therefore, the prognosis of patients with HF may be improved by taking appropriate management to control the EPA/AA balance. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

The effect of ionotropic gelation residence time on alginate cross-linking and properties.

PubMed

Patel, Mitulkumar A; AbouGhaly, Mohamed H H; Schryer-Praga, Jacqueline V; Chadwick, Keith

2017-01-02

The ability to engineer biocompatible polymers with controllable properties is highly desirable. One such approach is to cross-link carbohydrate polymers using ionotropic gelation (IG). Previous studies have investigated the effect of curing time on alginate cross-linking. Herein, we discuss a novel study detailing the effect of IG residence time (IGRT) on the cross-linking of alginate with calcium ions (Ca 2+ ) along with water migration (syneresis) and their subsequent impact on the pharmaceutical properties of alginate particles. IGRT was shown to have a significant effect on particle size, porosity, density, mechanical strength and swelling of calcium alginate particles as well as drug release mechanism. Furthermore, we describe a novel application of electron dispersive spectroscopy (EDS), in conjunction with Fourier Transform- infra red (FT-IR) spectroscopy, to analyze and monitor the changes in Ca 2+ concentration during cross-linking. A simple procedure to determine the concentration and distribution of the surface and internal Ca 2+ involved in alginate cross-linking was successfully developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-01-28

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

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

PubMed

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

2015-11-01

Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self-assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three-dimensional (3D) cell-printed scaffolds using layer-by-layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell-encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell-based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL-alginate gel constructs. PCL-alginate gels containing transforming growth factor-β (TGFβ) showed higher ECM formation. The 3D cell-printed scaffolds of PCL-alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL-alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell-printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. Copyright © 2013 John Wiley & Sons, Ltd.

Synthesis of Thiolated Alginate and Evaluation of Mucoadhesiveness, Cytotoxicity and Release Retardant Properties

PubMed Central

Jindal, A. B.; Wasnik, M. N.; Nair, Hema A.

2010-01-01

Modification of polymers by covalent attachment of thiol bearing pendant groups is reported to impart many beneficial properties to them. Hence in the present study, sodium alginate–cysteine conjugate was synthesized by carbodiimide mediated coupling under varying reaction conditions and the derivatives characterized for thiol content. The thiolated alginate species synthesized had bound thiol content ranging from 247.8±11.03–324.54±10.107 ΅mol/g of polymer depending on the reaction conditions. Matrix tablets based on sodium alginate-cysteine conjugate and native sodium alginate containing tramadol hydrochloride as a model drug were prepared and mucoadhesive strength and in vitro drug release from the tablets were compared. Tablets containing 75 mg sodium alginate-cysteine conjugate could sustain release of 10 mg of model drug for 3 h, whereas 90% of the drug was released within 1 h from corresponding tablets prepared using native sodium alginate. An approximately 2-fold increase in the minimal detachment force of the tablets from an artificial mucin film was observed for sodium alginate–cysteine conjugate as compared to native sodium alginate. In vitro cytotoxicity studies in L-929 mouse fibroblast cells studied using an MTT assay revealed that at low concentrations of polymer, sodium alginate–cysteine conjugate was less toxic to L-929 mouse fibroblast cell line when compared to native sodium alginate. Hence, thiolation is found to be a simple route to improving polymer performance. The combination of improved controlled drug release and mucoadhesive properties coupled with the low toxicity of these new excipients builds up immense scope for the use of thiolated polymers in mucoadhesive drug delivery systems. PMID:21969750

Aa Ah Nak

ERIC Educational Resources Information Center

Tha, Na Gya; Wus, Thay

2017-01-01

In this article, Aa Ah Nak, the authors' methodology presents not only various reflections but also diverse contradictions about the Aa Nii language as well as language revitalization. This article explores language foundation and how the Aa Nii language revitalization is inextricably linked to the genocide and resulting historic trauma pervasive…

Data on the effect of oral feeding of Arachidonic acid or Docosahexanoic acid on haematopoiesis in mice.

PubMed

Limbkar, Kedar; Dhenge, Ankita; Jadhav, Dipesh D; Thulasiram, Hirekodathakallu V; Kale, Vaijayanti; Limaye, Lalita

2017-10-01

Stem cells have peculiar property to self-renew and differentiate. It is important to control their fate in safe and effective ways for their therapeutic use. The mediators of essential polyunsaturated fatty acids (PUFAs) namely Arachidonic acid (AA) and Docosahexanoic acid (DHA) are known to play a role in haematopoiesis via various metabolic pathways [1]. However the direct effect of purified AA or DHA on haematopoiesis has not been well investigated yet. We have reported that oral administration of PUFAs enhanced haematopoiesis in mice [2]. Signaling Leukocyte Antigen Molecule (SLAM) (CD48 - CD150 + ) phenotype consists of pure population of haematopoietic stem cells (HSCs). Herein we observed higher percentage of SLAM (CD48 - CD150 + ) phenotype in the bone marrow (BM) cells of mice fed with AA or DHA compared to PBS fed control mice. Data from engraftment study depicts that BM from AA/DHA-fed mice showed higher absolute number of donor cells in recipient mice compared to control. The enhanced hematopoiesis observed in AA/DHA-fed mice was returned to normal when the mice were kept on normal diet for six weeks (after ten days of oral feeding). We confirmed GCMS (Gas Chromatography-Mass Spectroscopy) retention times of AA and DHA by co-injecting fatty acid extract from AA or DHA fed mice with purified AA or DHA standards respectively. Representative flow cytometry profile of Lin - Sca-1 + c-kit + (LSK) cells showed higher expression of CXCR4 protein and ligands of Wnt, Notch1 signaling in BM of AA/DHA-fed mice.

Chitosan/alginate complexes for vaginal delivery of chlorhexidine digluconate.

PubMed

Abruzzo, A; Bigucci, F; Cerchiara, T; Saladini, B; Gallucci, M C; Cruciani, F; Vitali, B; Luppi, B

2013-01-16

Chitosan/alginate complexes were prepared at different polycation/polyanion molar ratios and freeze-dried vaginal inserts were obtained for chlorhexidine digluconate local delivery in genital infections. Complex yield, FT-IR spectra, and TGA thermograms were studied to confirm the interaction between the two polyions. The influence of different complexes on physical handling, morphology, and drug distribution in the samples were evaluated by friability test, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), respectively. In vitro water-uptake, mucoadhesion and release tests were performed as well as microbiological tests toward pathogenic vaginal microorganisms. The results showed that the selection of suitable chitosan/alginate molar ratio and drug loading allowed modulate insert ability to hydrate, adhere to the mucosa, and release chlorhexidine digluconate. The insert containing an excess of alginate was found to be the best performing formulation and showed good antimicrobial activity toward the pathogens Candida albicans and Escherichia coli. Copyright © 2012 Elsevier Ltd. All rights reserved.

Methylene blue adsorption on graphene oxide/calcium alginate composites.

PubMed

Li, Yanhui; Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Wang, Yonghao; Wu, Shaoling; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

2013-06-05

Graphene oxide has been used as an adsorbent in wastewater treatment. However, the dispersibility in aqueous solution and the biotoxicity to human cells of graphene oxide limits its practical application in environmental protection. In this research, a novel environmental friendly adsorbent, calcium alginate immobilized graphene oxide composites was prepared. The effects of pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto calcium alginate immobilized graphene oxide composites were investigated. The equilibrium adsorption data were described by the Langmuir and Freundlich isotherms. The maximum adsorption capacity obtained from Langmuir isotherm equation was 181.81 mg/g. The pseudo-first order, pseudo-second order, and intraparticle diffusion equation were used to evaluate the kinetic data. Thermodynamic analysis of equilibriums indicated that the adsorption reaction of methylene blue onto calcium alginate immobilized graphene oxide composites was exothermic and spontaneous in nature. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Innovative plasticized alginate obtained by thermo-mechanical mixing: Effect of different biobased polyols systems.

PubMed

Gao, Chengcheng; Pollet, Eric; Avérous, Luc

2017-02-10

Plasticized alginate films with different biobased polyols (glycerol and sorbitol) and their mixtures were successfully prepared by thermo-mechanical mixing instead of the usual casting-evaporation procedure. The microstructure and properties of the different plasticized alginate formulations were investigated by SEM, FTIR, XRD, DMTA and uniaxial tensile tests. SEM and XRD results showed that native alginate particles were largely destructured with the plasticizers (polyols and water), under a thermo-mechanical input. With increasing amount of plasticizers, the samples showed enhanced homogeneity while their thermal and mechanical properties decreased. Compared to sorbitol, glycerol resulted in alginate films with a higher flexibility due to its better plasticization efficiency resulting from its smaller size and higher hydrophilic character. Glycerol and sorbitol mixtures seemed to be an optimum to obtain the best properties. This work showed that thermo-mechanical mixing is a promising method to produce, at large scale, plasticized alginate-based films with improved properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Antifibrotic effect of dexamethasone/alginate-coated silicone sheet in the abraded middle ear mucosa.

PubMed

Jang, Chul Ho; Ahn, Seung Hyun; Kim, Geun Hyung

2016-12-01

Silicone sheet is a material which is commonly used in middle ear surgery to prevent the formation of adhesions between the tympanic membrane and the medial bony wall of the middle ear cavity. However, silicone sheet can induce a tight and hard fibrous capsule in the region of the stapes, and this is particularly common in cases of eustachian tube dysfunction. As a result of the fibrous encapsulation around the silicone sheet, postoperative aeration of the stapes can be interrupted causing poor hearing gain. In this study, we performed an in vitro and in vivo evaluation of the antifibrotic effects of a dexamethasone and alginate (Dx/alginate) coating on silicone sheet. The Dx/alginate-coated silicone sheets were fabricated using a plasma-treatment and coating method. The Dx/alginate-coated silicone sheets effectively limited in vitro fibroblast attachment and proliferation due to the controlled release of Dx, which can be modified by manipulation of the alginate coating. For the in-vivo evaluation, guinea pigs (albino, male, weighing 250g) were divided into two groups, with the control group (n=5) implanted with silicone sheet and the test group (n=5) receiving Dx/alginate-coated silicone sheet. Animals were sacrificed 3 weeks after implantation, and histological analysis was performed using hematoxylin and eosin (H&E) and immunohistochemical staining techniques. Dx/alginate-coated silicone sheets showed marked inhibition of fibrosis in both the in vitro and in vivo studies. Silicone sheet that incorporates a Dx/alginate coating can release Dx and inhibit fibrosis in the middle ear. This material could be utilized in middle ear surgery as a means of preserving proper aeration and hearing gain following ossiculoplasty. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel alginate hydrogel core-shell systems for combination delivery of ranitidine HCl and aceclofenac.

PubMed

Jana, Sougata; Samanta, Abhijit; Nayak, Amit Kumar; Sen, Kalyan Kumar; Jana, Subrata

2015-03-01

A novel hydrogel system was successfully developed based on core-shell approach for the delivery of ranitidine HCl and aceclofenac. Aceclofenac-loaded alginate microspheres coated with eudragit L-100 was used as core material and that of freeze-thaw cross-linked chitosan-PVA gels containing ranitidine HCl served as the shell-forming material. The alginate microspheres coated with eudragit L-100 showed drug encapsulation efficiency of 56.06±1.12 to 68.03±2.16% and had average particle sizes of 551.29±25.92 to 677.18±27.05 μm. The viscosity of chitosan-PVA gels ranged between 505.74±1.04 and 582.41±2.09 cps. The formulations were characterized by FTIR, SEM and polarized microscopy analyses. The release of ranitidine HCl was comparatively higher in acidic medium (pH 1.2) than in alkaline medium (pH 7.4). The release of aceclofenac became slower in alkaline medium (pH 7.4) and continued up to 3.5 h. Super case-II transport mechanism was assumed for the release of ranitidine HCl in both media; whereas non-Fickian (anomalous) diffusion mechanism predominated in the release of aceclofenc. Thus, hydrogel-based core-shell formulations were found suitable for simultaneous delivery of aceclofenac and ranitidine HCl which could minimize the chances of excessive gastric acid secretion through suitable ranitidine HCl release in gastric region. Copyright © 2014. Published by Elsevier B.V.

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.

Amino Acid Medical Foods Provide a High Dietary Acid Load and Increase Urinary Excretion of Renal Net Acid, Calcium, and Magnesium Compared with Glycomacropeptide Medical Foods in Phenylketonuria

PubMed Central

Stroup, Bridget M.; Sawin, Emily A.; Murali, Sangita G.; Binkley, Neil; Hansen, Karen E.

2017-01-01

Background. Skeletal fragility is a complication of phenylketonuria (PKU). A diet containing amino acids compared with glycomacropeptide reduces bone size and strength in mice. Objective. We tested the hypothesis that amino acid medical foods (AA-MF) provide a high dietary acid load, subsequently increasing urinary excretion of renal net acid, calcium, and magnesium, compared to glycomacropeptide medical foods (GMP-MF). Design. In a crossover design, 8 participants with PKU (16–35 y) provided food records and 24-hr urine samples after consuming a low-Phe diet in combination with AA-MF and GMP-MF for 1–3 wks. We calculated potential renal acid load (PRAL) of AA-MF and GMP-MF and determined bone mineral density (BMD) measurements using dual X-ray absorptiometry. Results. AA-MF provided 1.5–2.5-fold higher PRAL and resulted in 3-fold greater renal net acid excretion compared to GMP-MF (p = 0.002). Dietary protein, calcium, and magnesium intake were similar. GMP-MF significantly reduced urinary excretion of calcium by 40% (p = 0.012) and magnesium by 30% (p = 0.029). Two participants had low BMD-for-age and trabecular bone scores, indicating microarchitectural degradation. Urinary calcium with AA-MF negatively correlated with L1–L4 BMD. Conclusion. Compared to GMP-MF, AA-MF increase dietary acid load, subsequently increasing urinary calcium and magnesium excretion, and likely contributing to skeletal fragility in PKU. The trial was registered at clinicaltrials.gov as NCT01428258. PMID:28546877

Human Periodontal Ligament- and Gingiva-derived Mesenchymal Stem Cells Promote Nerve Regeneration When Encapsulated in Alginate/Hyaluronic Acid 3D Scaffold.

PubMed

Ansari, Sahar; Diniz, Ivana M; Chen, Chider; Sarrion, Patricia; Tamayol, Ali; Wu, Benjamin M; Moshaverinia, Alireza

2017-12-01

Repair or regeneration of damaged nerves is still a challenging clinical task in reconstructive surgeries and regenerative medicine. Here, it is demonstrated that periodontal ligament stem cells (PDLSCs) and gingival mesenchymal stem cells (GMSCs) isolated from adult human periodontal and gingival tissues assume neuronal phenotype in vitro and in vivo via a subcutaneous transplantation model in nude mice. PDLSCs and GMSCs are encapsulated in a 3D scaffold based on alginate and hyaluronic acid hydrogels capable of sustained release of human nerve growth factor (NGF). The elasticity of the hydrogels affects the proliferation and differentiation of encapsulated MSCs within scaffolds. Moreover, it is observed that PDLSCs and GMSCs are stained positive for βIII-tubulin, while exhibiting high levels of gene expression related to neurogenic differentiation (βIII-tubulin and glial fibrillary acidic protein) via quantitative polymerase chain reaction (qPCR). Western blot analysis shows the importance of elasticity of the matrix and the presence of NGF in the neurogenic differentiation of encapsulated MSCs. In vivo, immunofluorescence staining for neurogenic specific protein markers confirms islands of dense positively stained structures inside transplanted hydrogels. As far as it is known, this study is the first demonstration of the application of PDLSCs and GMSCs as promising cell therapy candidates for nerve regeneration. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

2016-11-20

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

Adenoviral transduction supports matrix expression of alginate cultured articular chondrocytes.

PubMed

Pohle, D; Kasch, R; Herlyn, P; Bader, R; Mittlmeier, T; Pützer, B M; Müller-Hilke, B

2012-09-01

The present study examines the effects of adenoviral (Ad) transduction of human primary chondrocyte on transgene expression and matrix production. Primary chondrocytes were isolated from healthy articular cartilage and from cartilage with mild osteoarthritis (OA), transduced with an Ad vector and either immediately cultured in alginate or expanded in monolayer before alginate culture. Proteoglycan production was measured using dimethylmethylene blue (DMMB) assay and matrix gene expression was quantified by real-time PCR. Viral infection of primary chondrocytes results in a stable long time transgene expression for up to 13 weeks. Ad transduction does not significantly alter gene expression and matrix production if chondrocytes are immediately embedded in alginate. However, if expanded prior to three dimension (3D) culture in alginate, chondrocytes produce not only more proteoglycans compared to non-transduced controls, but also display an increased anabolic and decreased catabolic activity compared to non-transduced controls. We therefore suggest that successful autologous chondrocyte transplantation (ACT) should combine adenoviral transduction of primary chondrocytes with expansion in monolayer followed by 3D culture. Future studies will be needed to investigate whether the subsequent matrix production can be further improved by using Ad vectors bearing genes encoding matrix proteins. Copyright © 2012 Wiley Periodicals, Inc.

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.

Oxidative potential of ambient water-soluble PM2.5 measured by Dithiothreitol (DTT) and Ascorbic Acid (AA) assays in the southeastern United States: contrasts in sources and health associations

NASA Astrophysics Data System (ADS)

Fang, T.; Verma, V.; Bates, J. T.; Abrams, J.; Klein, M.; Strickland, M. J.; Sarnat, S. E.; Chang, H. H.; Mulholland, J. A.; Tolbert, P. E.; Russell, A. G.; Weber, R. J.

2015-11-01

The ability of certain components of particulate matter to induce oxidative stress through catalytic generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and have recently developed a similar semi-automated system using the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed using both assays. We found that water-soluble DTT activity on a per air volume basis was more spatially uniform than water-soluble AA activity. DTT activity was higher in winter than in summer/fall, whereas AA activity was higher in summer/fall compared to winter, with highest levels near highly trafficked highways. DTT activity was correlated with organic and metal species, whereas AA activity was correlated with water-soluble metals (especially water-soluble Cu, r=0.70-0.91 at most sites). Source apportionment models, Positive Matrix Factorization (PMF) and a Chemical Mass Balance Method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from secondary processes (e.g., organic aerosol oxidation or metal mobilization by formation of an aqueous particle with secondary acids) and traffic emissions to both DTT and AA activities in urban Atlanta. Biomass burning was a large source for DTT activity, but insignificant for AA. DTT activity was well correlated with PM2.5 mass (r=0.49-0.86 across sites/seasons), while AA activity did not co-vary strongly with mass. A linear model was developed to estimate DTT and AA activities for the central Atlanta Jefferson Street site, based on the CMB-E sources that are statistically significant with positive

Phosphatidic acid (PA) binds PP2AA1 to regulate PP2A activity and PIN1 polar localization.

PubMed

Gao, Hong-Bo; Chu, Yu-Jia; Xue, Hong-Wei

2013-09-01

Phospholipase D (PLD) exerts broad biological functions in eukaryotes through regulating downstream effectors by its product, phosphatidic acid (PA). Protein kinases and phosphatases, such as mammalian target of rapamycin (mTOR), Protein Phosphatase 1 (PP1) and Protein Phosphatase 2C (PP2C), are PA-binding proteins that execute crucial regulatory functions in both animals and plants. PA participates in many signaling pathways by modulating the enzymatic activity and/or subcellular localization of bound proteins. In this study, we demonstrated that PLD-derived PA interacts with the scaffolding A1 subunit of Protein Phosphatase 2A (PP2A) and regulates PP2A-mediated PIN1 dephosphorylation in Arabidopsis. Genetic and pharmacological studies showed that both PA and PP2A participate in the regulation of auxin distribution. In addition, both the phosphorylation status and polar localization of PIN1 protein were affected by PLD inhibitors. Exogenous PA triggered the membrane accumulation of PP2AA1 and enhanced the PP2A activity at membrane, while PLD inhibition resulted in the reduced endosomal localization and perinuclear aggregation of PP2AA1. These results demonstrate the important role of PLD-derived PA in normal PP2A-mediated PIN dephosphorylation and reveal a novel mechanism, in which PA recruits PP2AA1 to the membrane system and regulates PP2A function on membrane-targeted proteins. As PA and PP2A are conserved among eukaryotes, other organisms might use similar mechanisms to mediate multiple biological processes.

Improvement of stability of oil-in-water emulsions containing caseinate-coated droplets by addition of sodium alginate.

PubMed

Pallandre, S; Decker, E A; McClements, D J

2007-11-01

The potential of sodium alginate for improving the stability of emulsions containing caseinate-coated droplets was investigated. One wt% corn oil-in-water emulsions containing anionic caseinate-coated droplets (0.15 wt% sodium caseinate) and anionic sodium alginate (0 to 1 wt%) were prepared at pH 7. The pH of these emulsions was then adjusted to 3.5, so that the anionic alginate molecules adsorbed to the cationic caseinate-coated droplets. Extensive droplet aggregation occurred when there was insufficient alginate to completely saturate the droplet surfaces due to bridging flocculation, and when the nonadsorbed alginate concentration was high enough to induce depletion flocculation. Emulsions with relatively small particle sizes could be formed over a range of alginate concentrations (0.1 to 0.4 wt%). The influence of pHs (3 to 7) and sodium chloride (0 to 500 mM) on the properties of primary (0 wt% alginate) and secondary (0.15 wt% alginate) emulsions was studied. Alginate adsorbed to the droplet surfaces at pHs 3, 4, and 5, but not at pHs 6 and 7, due to electrostatic attraction between anionic groups on the alginate and cationic groups on the adsorbed caseinate. Secondary emulsions had better stability than primary emulsions at pH values near caseinate's isoelectric point (pHs 4 and 5). In addition, secondary emulsions were stable up to higher ionic strengths (< 300 mM) than primary emulsions (<50 mM). The controlled electrostatic deposition method utilized in this study could be used to extend the range of application of dairy protein emulsifiers in the food industry.

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

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

PubMed

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

2017-06-07

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

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

Kefiran-alginate gel microspheres for oral delivery of ciprofloxacin.

PubMed

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

2016-09-01

Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrospray-assisted encapsulation of caffeine in alginate microhydrogels.

PubMed

Nikoo, Alireza Mehregan; Kadkhodaee, Rassoul; Ghorani, Behrouz; Razzaq, Hussam; Tucker, Nick

2018-05-02

One of the major challenges with microencapsulation and delivery of low molecular weight bioactive compounds is their diffusional loss during storage and process conditions as well as under gastric conditions. In an attempt to slow down the release rate of core material, electrospray fabricated calcium alginate microhydrogels were coated with low molecular weight and high molecular weight chitosans. Caffeine as a hydrophilic model compound was used due to its several advantages on human behavior especially increasing consciousness. Mathematical modeling of the caffeine release by fitting the data with Korsmeyer-Peppas model showed that Fick's diffusion law could be the prevalent mechanism of the release. Electrostatic interaction between alginate and chitosan (particularly in the presence of 1% low molecular weight chitosan) provided an effective barrier against caffeine release and significantly reduced swelling of particles compared to control samples. The results of this study demonstrated that calcium alginate microhydrogels coated by chitosan could be used for encapsulation of low molecular compounds. However, more complementary research must be done in this field. In addition, electrospray, by producing monodisperse particles, would be as an alternative method for fabrication of microparticles based on natural polymers. Copyright © 2018. Published by Elsevier B.V.

Analysis of abietic acid and dehydroabietic acid residues in raw ducks and cooked ducks.

PubMed

Zhu, Yongzhi; Zhang, Suzhen; Geng, Zhiming; Wang, Daoying; Liu, Fang; Zhang, Muhan; Bian, Huan; Xu, Weimin

2014-10-01

Rosin was once widely used for removal of duck feathers in China and is still being used secretly in some poultry processing enterprises. Abietic acid (AA) and dehydroabietic acid (DHAA) are the major compounds of rosin. In the present study, 90 duck samples were collected for investigation of AA and DHAA residues. Abietic acid and DHAA were simultaneously detected in 13 out 40 raw ducks, 8 out of 26 water-boiled salted ducks, and 7 out of 24 roasted ducks, respectively. In positive samples, averages of AA were significantly higher than those of DHAA in positive samples of the 3 types of ducks (P < 0.05). Averages of AA and DHAA in positive raw ducks were significantly higher than those in positive roasted ducks (P < 0.05). The results indicated that almost one-third of raw ducks were defeathered by means of rosin-containing defeathering agent, and cooking processes could reduce the AA and DHAA residues to some extent, but could not eliminate them completely. ©2014 Poultry Science Association Inc.

Portable electrochemical sensor based on 4-aminobenzoic acid-functionalized herringbone carbon nanotubes for the determination of ascorbic acid and uric acid in human fluids.

PubMed

Abellán-Llobregat, A; González-Gaitán, C; Vidal, L; Canals, A; Morallón, E

2018-06-30

A new portable electrochemical sensor based on 4-aminobenzoic acid-modified herringbone carbon nanotubes (hCNTs-4ABA/Au-IDA) has been developed for the simultaneous determination of ascorbic acid (AA) and uric acid (UA) in physiological fluids. AA and UA were quantified by chronoamperometry at 0.1 and 0.32 V, respectively, in phosphate buffer solution (PBS 0.25 M, pH 7.0). Significant results were obtained for the separate quantification of AA and UA, with a limit of detection (LOD) of 0.65 μM for both analytes, and sensitivities of (9.0 ± 0.4) A g -1 mM -1 and (8.8 ± 0.3) A g -1 mM -1 for AA and UA, respectively. Repeatability was studied at 50 μM for AA and UA, providing relative standard deviations (RSD) lower than 9%. Additions of glucose, dopamine and epinephrine did not interfere with the AA and UA determination. Furthermore, UA did not interfere with AA determination at 0.1 V, although AA additions increased the current recorded at 0.32 V. The method has been successfully applied to human urine, perspiration and serum samples, without significant matrix effects, which allows for the use of an external calibration and the analysis of all the matrices investigated. Copyright © 2018 Elsevier B.V. All rights reserved.

The role of an alginate suspension on pepsin and bile acids - key aggressors in the gastric refluxate. Does this have implications for the treatment of gastro-oesophageal reflux disease?

PubMed

Strugala, Vicki; Avis, Jeanine; Jolliffe, Ian G; Johnstone, Lesley M; Dettmar, Peter W

2009-08-01

During a reflux event the oesophagus is exposed to a heterogeneous mixture of gastric juice components. The role of non-acid components of the refluxate in causing damage to the oesophagus is now well established but no therapeutic option exists to address this. The role of Gaviscon Advance (GA), a raft-forming alginate suspension, in protecting the oesophagus from damage by pepsin and bile acids (aggressors) was investigated using a series of in-vitro models. GA was able to dose-dependently inhibit pepsin activity over and above the neutralisation effect of the formulation. This was evident against both protein and collagen substrates using two distinct colorimetric assays. GA was able to retard the diffusion of pepsin and multiple bile acids using a Franz cell model. Using the raft-forming mode of action GA was able to remove both pepsin and multiple bile acids from a simulated reflux event. There was capacity in the GA raft to accommodate aggressors from multiple reflux events. GA can specifically remove both pepsin and bile acids from the refluxate, limit their diffusion and affect enzymatic activity of pepsin. There is a role for GA to reduce the damaging potential of the refluxate and thus protect the oesophagus.

Carbon-11 and Fluorine-18 Labeled Amino Acid Tracers for Positron Emission Tomography Imaging of Tumors

NASA Astrophysics Data System (ADS)

Sun, Aixia; Liu, Xiang; Tang, Ganghua

2017-12-01

Tumor cells have an increased nutritional demand for amino acids(AAs) to satisfy their rapid proliferation. Positron-emitting nuclide labeled AAs are interesting probes and are of great importance for imaging tumors using positron emission tomography (PET). Carbon-11 and fluorine-18 labeled AAs include the [1-11C] amino acids, labeling alpha-C- amino acids, the branched-chain of amino acids and N-substituted carbon-11 labeled amino acids. These tracers target protein synthesis or amino acid(AA) transport, and their uptake mechanism mainly involves AA transport. AA PET tracers have been widely used in clinical settings to image brain tumors, neuroendocrine tumors, prostate cancer, breast cancer, non–small cell lung cancer (NSCLC) and hepatocellular carcinoma. This review focuses on the fundamental concepts and the uptake mechanism of AAs, AA PET tracers and their clinical applications.

ARISTOLOCHIC ACID I METABOLISM IN THE ISOLATED PERFUSED RAT KIDNEY

PubMed Central

Priestap, Horacio A.; Torres, M. Cecilia; Rieger, Robert A.; Dickman, Kathleen G.; Freshwater, Tomoko; Taft, David R.; Barbieri, Manuel A.; Iden, Charles R.

2012-01-01

Aristolochic acids are natural nitro-compounds found globally in the plant genus Aristolochia that have been implicated in the severe illness in humans termed aristolochic acid nephropathy (AAN). Aristolochic acids undergo nitroreduction, among other metabolic reactions, and active intermediates arise that are carcinogenic. Previous experiments with rats showed that aristolochic acid I (AA-I), after oral administration or injection, is subjected to detoxication reactions to give aristolochic acid Ia, aristolactam Ia, aristolactam I and their glucuronide and sulfate conjugates that can be found in urine and faeces. Results obtained with whole rats do not clearly define the role of liver and kidney in such metabolic transformation. In this study, in order to determine the specific role of the kidney on the renal disposition of AA-I and to study the biotransformations suffered by AA-I in this organ, isolated kidneys of rats were perfused with AA-I. AA-I and metabolite concentrations were determined in perfusates and urines using HPLC procedures. The isolated perfused rat kidney model showed that AA-I distributes rapidly and extensively in kidney tissues by uptake from the peritubular capillaries and the tubules. It was also established that the kidney is able to metabolize AA-I into aristolochic acid Ia, aristolochic acid Ia O-sulfate, aristolactam Ia, aristolactam I and aristolactam Ia O-glucuronide. Rapid demethylation and sulfation of AA-I in the kidney generate aristolochic acid Ia and its sulfate conjugate that are voided to the urine. Reduction reactions to give the aristolactam metabolites occur to a slower rate. Renal clearances showed that filtered AA-I is reabsorbed at the tubules whereas the metabolites are secreted. The unconjugated metabolites produced in the renal tissues are transported to both urine and perfusate whereas the conjugated metabolites are almost exclusively secreted to the urine. PMID:22118289

Clinical use of proton-pump inhibitors but not H2-blockers or antacid/alginates raises the serum levels of amidated gastrin-17, pepsinogen I and pepsinogen II in a random adult population.

PubMed

Agréus, Lars; Storskrubb, Tom; Aro, Pertti; Ronkainen, Jukka; Talley, Nicholas J; Sipponen, Pentti

2009-01-01

Proton-pump inhibitors (PPIs), H(2) receptor antagonists (H(2)RAs) and antacids/alginates reduce intragastric acidity and may thus influence normal gastric physiology. The purpose of this study was to examine the effect of these compounds on serum levels of amidated gastrin-17 (G-17) and pepsinogens (PGI & PGII) in a large, random, adult Swedish population sample with uninfected stomach mucosa. The initial sample subjects (n=1000, mean age 50 years, range 20-80 years) completed a questionnaire on the use of acid inhibitory drugs 1 week and/or 3 months before study entry. All subjects (n=590) with normal gastric mucosa as delineated by serum biomarkers were included. Among them, serum levels of PGI, PGII and G-17 were compared between those who used acid inhibitory drugs and those who did not. The serum levels of G-17 or pepsinogens in the subjects who reported use of H(2)RAs (n=18) or antacid/alginates (n=66) during the previous 3 months did not differ from those in non-users (n=471). However, the median levels of G-17 and pepsinogens were significantly (p<0.001) higher among the PPI users (n=35) than among non-users: the levels were approximately doubled. The ratio of PGI/PGII was, however, similar between PPI users and non-users, or those using antacids/alginates or H(2)RAs. Among subjects using PPIs, the serum levels of pepsinogens correlated positively (p<0.01) with the serum levels of G-17. PPIs but not antacids/alginates or H(2)RAs markedly increase the fasting levels of serum amidated G-17 and pepsinogens among ordinary patients in everyday clinical practice.

Core-shell alginate-ghatti gum modified montmorillonite composite matrices for stomach-specific flurbiprofen delivery.

PubMed

Bera, Hriday; Ippagunta, Sohitha Reddy; Kumar, Sanoj; Vangala, Pavani

2017-07-01

Novel alginate-arabic gum (AG) gel membrane coated alginate-ghatti gum (GG) modified montmorillonite (MMT) composite matrices were developed for intragastric flurbiprofen (FLU) delivery by combining floating and mucoadhesion mechanisms. The clay-biopolymer composite matrices containing FLU as core were accomplished by ionic-gelation technique. Effects of polymer-blend (alginate:GG) ratios and crosslinker (CaCl 2 ) concentrations on drug entrapment efficiency (DEE, %) and cumulative drug release after 8h (Q 8h , %) were studied to optimize the core matrices by a 3 2 factorial design. The optimized matrices (F-O) demonstrated DEE of 91.69±1.43% and Q 8h of 74.96±1.56% with minimum errors in prediction. The alginate-AG gel membrane enveloped optimized matrices (F-O, coated) exhibited superior buoyancy, better ex vivo mucoadhesion and slower drug release rate. The drug release profile of FLU-loaded uncoated and coated optimized matrices was best fitted in Korsmeyer-Peppas model with anomalous diffusion and case-II transport driven mechanism, respectively. The uncoated and coated matrices containing FLU were also characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the newly developed alginate-AG gel membrane coated alginate-GG modified MMT composite matrices are appropriate for intragastric delivery of FLU over an extended period of time with improved therapeutic benefits. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed Central

Kim, Yeon Seong; Jeong, Young-II; Jin, Shu-Guang; Pei, Jian; Wen, Min; Kim, In-Young; Moon, Kyung-Sub; Jung, Tae-Young; Ryu, Hyang-Hwa; Jung, Shin

2013-01-01

Background In this study, 293T cells were genetically engineered to secrete tissue inhibitor of metalloproteinase-2 (TIMP2) and encapsulated into alginate microcapsules to continuously release TIMP2 protein. Methods The anti-invasive potential of the microcapsules was studied in vitro using brain tumor cells. The TIMP2 gene was transfected to 293T cells, and genetically engineered 293TIMP2 cells were encapsulated into alginate microcapsules. Release of TIMP2 protein was detected with Western blot analysis and the anti-invasive potential against U87MG cells was tested using gelatin zymography and a Matrigel assay. Results Cell viability within the alginate microcapsules was maintained at a cell density of 5 × 106. Because polycationic polymers are helpful for maintaining the mechanical strength of microcapsules with good cell viability, the alginate microcapsules were reinforced with chitosan (0.1% w/v). Expression of TIMP2 protein in cell lysates and secretion of TIMP2 into the conditioned medium was confirmed by Western blot analysis. Alginate microcapsules encapsulating 293TIMP2 cells released TIMP2 protein into the medium efficiently, where the TIMP2 protein participated in degradation of the matrix metalloproteinase-2 enzyme and inhibited invasion of U87MG cells. Conclusion Alginate microcapsules encapsulating 293TIMP2 cells are promising candidates for anti-invasive treatment of glioma. PMID:24231999

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.

Fabrication of monodispersive nanoscale alginate-chitosan core-shell particulate systems for controlled release studies

NASA Astrophysics Data System (ADS)

Körpe, Didem Aksoy; Malekghasemi, Soheil; Aydın, Uğur; Duman, Memed

2014-12-01

Biopolymers such as chitosan and alginate are widely used for controlled drug delivery systems. The present work aimed to develop a new protocol for preparation of monodisperse alginate-coated chitosan nanoparticles at nanoscale. Modifications of preparation protocol contain changing the pH of polymer solutions and adding extra centrifugation steps into the procedure. While chitosan nanoparticles were synthesized by ionic gelation method, they were coated with alginate by electrostatic interaction. The size, morphology, charge, and structural characterization of prepared core-shell nanoparticulated system were performed by AFM, Zeta sizer, and FTIR. BSA and DOX were loaded as test biomolecules to core and shell part of the nanoparticle, respectively. Release profiles of BSA and DOX were determined by spectrophotometry. The sizes of both chitosan and alginate-coated chitosan nanoparticles which were prepared by modified protocol were measured to be 50 ± 10 and 60 ± 3 nm, respectively. After loading BSA and DOX, the average size of the particles increased to 80 ± 7 nm. Moreover, while the zeta potential of chitosan nanoparticles was positive value, the value was inverted to negative after alginate coating. Release profile measurements of BSA and DOX were determined during 57 and 2 days, respectively. Our results demonstrated that monodisperse alginate-coated nanoparticles were synthesized and loaded successfully using our modified protocol.

Development of silver nanoparticles loaded chitosan-alginate constructs with biomedical potentialities.

PubMed

Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M N; Li, Chuanlong; Hu, Hongbo; Zhang, Xuehong

2017-12-01

Herein, a facile biosynthesis of silver nanoparticles (AgNPs) and AgNPs-loaded chitosan-alginate constructs with biomedical potentialities is reported. The UV-vis spectroscopic profile confirmed the synthesis of AgNPs using methanolic leaves extract of Euphorbia helioscopia. The newly developed AgNPs were characterized using various analytical and imaging techniques including UV-vis and FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The optimally yielded AgNPs at 24h reaction period were loaded onto various chitosan-alginate constructs. A maximum of 95% loading efficiency (LE) was recorded with a chitosan: alginate ratio at 2:1, followed by 81% at 2:2 ratios. The anti-bacterial activities of AgNPs and AgNPs loaded chitosan-alginate constructs were tested against six bacterial strains i.e. Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Morganella morganii and Haemophilus influenza. A significant reduction in the log values was recorded for all test constructs, in comparison to the initial bacterial count (control value, i.e., 1.5×10 8 CFU/mL). The cytotoxicity profile revealed complete biocompatibility against normal cell line i.e. L929. Almost all constructs showed considerable cytotoxicity up to certain extant against human epithelial cells (HeLa) cancer cells. In summary, the highest antibacterial activities along with anti-cancer behavior both suggest the biomedical potentialities of newly engineered AgNPs and AgNPs-loaded chitosan-alginate constructs. Copyright © 2017 Elsevier B.V. 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

Work of adhesion between mucin macromolecule and calcium-alginate gels on molecular level.

PubMed

Popeski-Dimovski, Riste

2015-06-05

The bioadhesion of biopolymers to mucus layers is of great interest for the development of drug delivery systems. Herein we use AFM force measurements to evaluate the interaction on molecular level between a mucin macromolecule attached to an AFM tip and a calcium-alginate gel layer. The total work of adhesion is measured from the AFM force curves depending on different parameters: time of contact, G/M ratio of the alginate, and crosslink ratio of the gel. The total work of adhesion is found to be in the range of 1×10(-19) to 6×10(-18)J. The results show that the work of adhesion increases with the time of contact but it is independent from the molecular mass of the alginate, the G/M ratio of the alginate and crosslink ratio of the gel. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anger induced by interferon-alpha is moderated by ratio of arachidonic acid to omega-3 fatty acids.

PubMed

Lotrich, Francis E; Sears, Barry; McNamara, Robert K

2013-11-01

Anger worsens in some patients during interferon-alpha (IFN-α) therapy. Elevated anger has also been associated with lower long-chain omega-3 (LCn-3) fatty acid levels. We examined whether fatty acids could influence vulnerability to anger during IFN-α exposure. Plasma arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) levels were determined prior to IFN-α therapy by mass spectroscopy. Repeated-measure analyses examined the relationship between AA/EPA+DHA and the subsequent development of labile anger and irritability in 82 subjects who prospectively completed the Anger, Irritability, and Assault Questionnaire (AIAQ) during the first eight weeks of IFN-α therapy. Prior to IFN-α therapy, AA/EPA+DHA did not correlate with either labile anger or irritability. Pre-treatment AA/EPA+DHA did correlate with the subsequent maximal increase in labile anger during IFN-α therapy (r=0.33; p=0.005). Over time, labile anger increased more in subjects with above median AA/EPA+DHA ratios (p<0.05). Of the 17 subjects ultimately requiring psychiatric intervention for anger, 14/17 had above-median AA/EPA+DHA ratios (p=0.009). There was also an interaction with the tumor necrosis factor-alpha (TNF-α) promoter polymorphism (A-308G), such that only those with both elevated AA/EPA+DHA and the A allele had increased labile anger (p=0.001). In an additional 18 subjects, we conversely observed that selective serotonin reuptake inhibitor treatment was associated with increased irritability during IFN-α therapy. LCn-3 fatty acid status may influence anger development during exposure to elevated inflammatory cytokines, and may interact with genetic risk for increased brain TNF-α. LCn-3 supplements may be one strategy for minimizing this adverse side effect of IFN-α. © 2013.

Sodium alginate hydrogel-based bioprinting using a novel multinozzle bioprinting system.

PubMed

Song, Seung-Joon; Choi, Jaesoon; Park, Yong-Doo; Hong, Soyoung; Lee, Jung Joo; Ahn, Chi Bum; Choi, Hyuk; Sun, Kyung

2011-11-01

Bioprinting is a technology for constructing bioartificial tissue or organs of complex three-dimensional (3-D) structure with high-precision spatial shape forming ability in larger scale than conventional tissue engineering methods and simultaneous multiple components composition ability. It utilizes computer-controlled 3-D printer mechanism or solid free-form fabrication technologies. In this study, sodium alginate hydrogel that can be utilized for large-dimension tissue fabrication with its fast gelation property was studied regarding material-specific printing technique and printing parameters using a multinozzle bioprinting system developed by the authors. A sodium alginate solution was prepared with a concentration of 1% (wt/vol), and 1% CaCl(2) solution was used as cross-linker for the gelation. The two materials were loaded in each of two nozzles in the multinozzle bioprinting system that has a total of four nozzles of which the injection speed can be independently controlled. A 3-D alginate structure was fabricated through layer-by-layer printing. Each layer was formed through two phases of printing, the first phase with the sodium alginate solution and the second phase with the calcium chloride solution, in identical printing pattern and speed condition. The target patterns were lattice shaped with 2-mm spacing and two different line widths. The nozzle moving speed was 6.67 mm/s, and the injection head speed was 10 µm/s. For the two different line widths, two injection needles with inner diameters of 260 and 410 µm were used. The number of layers accumulated was five in this experiment. By varying the nozzle moving speed and the injection speed, various pattern widths could be achieved. The feasibility of sodium alginate hydrogel free-form formation by alternate printing of alginate solution and sodium chloride solution was confirmed in the developed multinozzle bioprinting system. © 2011, Copyright the Authors. Artificial Organs © 2011, International

A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

PubMed Central

Mollerup, Filip; Parikka, Kirsti; Koutaniemi, Sanna; Boer, Harry; Juvonen, Minna; Master, Emma; Tenkanen, Maija; Kruus, Kristiina

2017-01-01

ABSTRACT We describe here the identification and characterization of a copper radical oxidase from auxiliary activities family 5 (AA5_2) that was distinguished by showing preferential activity toward raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase from Colletotrichum graminicola (CgRaOx; EC 1.1.3.−) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase. CgRaOx was expressed in Pichia pastoris, and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on d-galactose at a 300 mM substrate concentration. Thus, the substrate preference of CgRaOx was distinguished clearly from the substrate preferences of the known galactose oxidases. The site of oxidation for raffinose was studied by 1H nuclear magnetic resonance and mass spectrometry, and we confirmed that the hydroxyl group at the C-6 position was oxidized to an aldehyde and that in addition uronic acid was produced as a side product. A new electrospray ionization mass spectrometry method for the identification of C-6 oxidized products was developed, and the formation mechanism of the uronic acid was studied. CgRaOx presented a novel activity pattern in the AA5 family. IMPORTANCE Currently, there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O2 without the requirement of complex cofactors such as FAD or NAD(P). Here, we present the identification and characterization of a novel AA5 member from Colletotrichum graminicola. As discussed in the present study, the bioinformatics approach using the modular structure of

Consequences of the Combined α-tocopherol, Ascorbic Acid and α-lipoic Acid on the Glutathione, Cholesterol and Fatty Acid Composition in Muscle and Liver of Diabetic Rats

PubMed Central

YILMAZ, Okkes; ERSAN, Yasemin; Dilek OZSAHIN, Ayse; Ihsan OZTURK, Ali; OZKAN, Yusuf

2013-01-01

Objective(s): Our objective was to evaluate the effects of a triple antioxidant combination [α-tocopherol (AT), ascorbic acid (AA) and α-lipoic acid (LA); AT+AA+LA] on the cholesterol and glutathione levels, and the fatty acid composition of liver and muscle tissues in diabetic rats. Materials and Methods: Forty-three Wistar rats were randomly divided into five groups. The first group was used as a control. The second, third and fourth groups received STZ (45 mg/kg) in citrate buffer. The fourth and fifth groups were injected with intraperitoneal (IP) 50 mg/kg DL-AT and 50 mg /kg DL-LA four times per week and received water-soluble vitamin C (50 mg/kg) in their drinking water for a period of six weeks. Results: Liver cholesterol levels in the AT+AA+LA group were lower than the control (P<0.05). Glutathione level was lower in D-2 (P<0.05) and were higher in D+AT+AA+LA and AT+AA+LA groups than the control groups (P≤ 0.05). The muscle cholesterol levels in the D-1 and D+AT+AA+LA groups were higher than the control group (P≤ 0.05). The levels of oleic acid were higher in the D-1 group and lower in the D-2 group (P<0.001). The arachidonic acid level in the D-1 and D-2 groups were lower (P<0.05), and higher in the D+AT+AA+LA group. Conclusion: Our results revealed that glutathione levels and the Stearoyl CoA Desaturase enzyme products in liver tissues of diabetic and non-diabetic rats were increased by triple antioxidant mixture. PMID:24298385

Consequences of the Combined α-tocopherol, Ascorbic Acid and α-lipoic Acid on the Glutathione, Cholesterol and Fatty Acid Composition in Muscle and Liver of Diabetic Rats.

PubMed

Yilmaz, Okkes; Ersan, Yasemin; Dilek Ozsahin, Ayse; Ihsan Ozturk, Ali; Ozkan, Yusuf

2013-02-01

Our objective was to evaluate the effects of a triple antioxidant combination [α-tocopherol (AT), ascorbic acid (AA) and α-lipoic acid (LA); AT+AA+LA] on the cholesterol and glutathione levels, and the fatty acid composition of liver and muscle tissues in diabetic rats. Forty-three Wistar rats were randomly divided into five groups. The first group was used as a control. The second, third and fourth groups received STZ (45 mg/kg) in citrate buffer. The fourth and fifth groups were injected with intraperitoneal (IP) 50 mg/kg DL-AT and 50 mg /kg DL-LA four times per week and received water-soluble vitamin C (50 mg/kg) in their drinking water for a period of six weeks. Liver cholesterol levels in the AT+AA+LA group were lower than the control (P<0.05). Glutathione level was lower in D-2 (P<0.05) and were higher in D+AT+AA+LA and AT+AA+LA groups than the control groups (P≤ 0.05). The muscle cholesterol levels in the D-1 and D+AT+AA+LA groups were higher than the control group (P≤ 0.05). The levels of oleic acid were higher in the D-1 group and lower in the D-2 group (P<0.001). The arachidonic acid level in the D-1 and D-2 groups were lower (P<0.05), and higher in the D+AT+AA+LA group. Our results revealed that glutathione levels and the Stearoyl CoA Desaturase enzyme products in liver tissues of diabetic and non-diabetic rats were increased by triple antioxidant mixture.

Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo

PubMed Central

Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

2018-01-01

Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. Methods In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. Results We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling

Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo.

PubMed

Jing, Yue; Wang, Gang; Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

2018-01-01

Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling. For the first time

Free-standing polyelectrolyte membranes made of chitosan and alginate

PubMed Central

Caridade, Sofia G.; Monge, Claire; Gilde, Flora; Boudou, Thomas; Mano, João F.; Picart, Catherine

2014-01-01

Free-standing films have increasing applications in the biomedical field as drug delivery systems, for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce thick membrane, to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any post-processing step. They dry thickness was varied over a large range from 4 to 35 μm. A two-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side. PMID:23590116

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.

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.

Synthesis and characterization of guar-alginate hybrid bead templated mercury sorbing titania spheres.

PubMed

Singh, Vandana; Preeti; Singh, Angela; Singh, Devendra; Singh, Yadveer; Pandey, Arvind Kumar

2015-01-01

Present communication reports on the synthesis and characterization of Hg(II) sorbing millimeter sized porous titania spheres (TSP). The synthesis utilizes guar gum-alginate hybrid beads as sacrificial template to polymerize titanium(IV) isopropoxide. The hybrid beads are crafted by pouring guar-alginate mixed solution to calcium bath. The mechanical strength of the beads depended on guar to alginate ratio in the mixed solution. The equal weight ratio of the two polysaccharides is appropriate for adequate mechanical strength beads. The unique performance of the templating beads is attributed to the synergistic interaction between guar gum and sodium alginate. FTIR, BET, SEM, TEM, XRD, TGA, and DTG analyses have been used for the characterization of the optimum performance TSP (TSPAG2). TSPAG2 is a mesoporous material that has higher surface area and narrower pore size distribution than pure alginate derived titania spheres (TSPA). TEM study demonstrated that TSPAG2 spheres are constituted of aggregated TiO2 nanoparticles of ∼ 10 nm size. TSPAG2 is able to capture >95% Hg(II) from synthetic Hg(II) solution in 10h at pH 5 as opposed to only 68% removal by TSPA. Copyright © 2014 Elsevier B.V. All rights reserved.

Citric acid production using immobilized conidia of Aspergillus niger TMB 2022

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

Tsay, S.S.; To, K.Y.

1987-02-20

Conidia of Aspergillus niger TMB 2022 were immobilized in calcium alginate for the production of citric acid. A 1-ml condidia suspension containing ca. 2.32 x 10/sup 8/ conidia were entrapped into sodium alginate solution in order to prepare 3% Ca-alginate (w/v) gel bead. Immobilized conidia were inoculated into productive medium containing 14% sucrose, 0.25% (NH/sub 4/)/sub 2/CO/sub 3/, 0.25% KH/sub 2/PO/sub 4/, and 0.025% MgSO/sub 4/.7H/sub 2/O with addition of 0.06 mg/l CuSO/sub 4/.5H/sub 2/O, 0.25 mg/l ZnCl/sub 2/, 1.3 mg/l FeCl/sub 3/.6H/sub 2/O, pH 3.8, and incubated at 35 degrees C for 13 days by surface culture to producemore » 61.53 g/l anhydrous citric acid. Under the same conditions with a batchwise culture, it was found that immobilized conidia could maintain a longer period for citric acid production (31 days): over 70 g/l anhydrous citric acid from runs No. 2-4, with the maximum yield for anhydrous citric acid reaching 77.02 g/l for run No. 2. In contrast, free conidia maintained a shorter acid-producing phase, circa 17 days; the maximum yield for anhydrous citric acid was 71.07 g/l for run No. 2 but dropped quickly as the run number increased. 14 references.« less

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.

Doxorubicin-loaded poly (lactic-co-glycolic acid) nanoparticles coated with chitosan/alginate by layer by layer technology for antitumor applications.

PubMed

Chai, Fujuan; Sun, Linlin; He, Xinyi; Li, Jieli; Liu, Yuanfen; Xiong, Fei; Ge, Liang; Webster, Thomas J; Zheng, Chunli

2017-01-01

Natural polyelectrolyte multilayers of chitosan (CHI) and alginate (ALG) were alternately deposited on doxorubicin (DOX)-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) with layer by layer self-assembly to control drug release for antitumor activity. Numerous factors which influenced the multilayer growth on nano-colloidal particles were studied: polyelectrolyte concentration, NaCl concentration and temperature. Then the growth regime of the CHI/ALG multilayers was elucidated. The coated NPs were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction and a zeta potential analyzer. In vitro studies demonstrated an undesirable initial burst release of DOX-loaded PLGA NPs (DOX-PLGA NPs), which was relieved from 55.12% to 5.78% through the use of the layer by layer technique. The release of DOX increased more than 40% as the pH of media decreased from 7.4 to 5.0. More importantly, DOX-PLGA (CHI/ALG) 3 NPs had superior in vivo tumor inhibition rates at 83.17% and decreased toxicity, compared with DOX-PLGA NPs and DOX in solution. Thus, the presently formulated PLGA-polyelectrolyte NPs have strong potential applications for numerous controlled anticancer drug release applications.

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.

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

PubMed

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

2015-08-01

The trend of using biopolymers in combination with synthetic polymers was increasing rapidly from last two or three decades. Polysaccharide based biopolymers especially starch, cellulose, chitin, chitosan, alginate, etc. found extensive applications for different industrial uses, as they are biocompatible, biodegradable, bio-renewable resources and chiefly environment friendly. Segment block copolymer character of polyurethanes that endows them a broad range of versatility in terms of tailoring their properties was employed in conjunction with various natural polymers resulted in modified biomaterials. Alginate is biodegradable, biocompatible, bioactive, less toxic and low cost anionic polysaccharide, as a part of structural component of bacteria and brown algae (sea weed) is quite abundant in nature. It is used in combination with polyurethanes to form elastomers, nano-composites, hydrogels, etc. that especially revolutionized the food and biomedical industries. The review summarized the development in alginate based polyurethanes with their potential applications. Copyright © 2015 Elsevier B.V. All rights reserved.

The ratio of serum eicosapentaenoic acid to arachidonic acid and risk of cancer death in a Japanese community: The Hisayama Study.

PubMed

Nagata, Masaharu; Hata, Jun; Hirakawa, Yoichiro; Mukai, Naoko; Yoshida, Daigo; Ohara, Tomoyuki; Kishimoto, Hiro; Kawano, Hiroyuki; Kitazono, Takanari; Kiyohara, Yutaka; Ninomiya, Toshiharu

2017-12-01

Whether the intake of eicosapentaenoic acid (EPA) or arachidonic acid (AA) affects the risk of cancer remains unclear, and the association between the serum EPA:AA ratio and cancer risk has not been fully evaluated in general populations. A total of 3098 community-dwelling subjects aged ≥40 years were followed up for 9.6 years (2002-2012). The levels of the serum EPA:AA ratio were categorized into quartiles (<0.29, 0.29-0.41, 0.42-0.60, and >0.60). The risk estimates were computed using a Cox proportional hazards model. The same analyses were conducted for the serum docosahexaenoic acid to arachidonic acid (DHA:AA) ratio and individual fatty acid concentrations. During the follow-up period, 121 subjects died of cancer. Age- and sex-adjusted cancer mortality increased with lower serum EPA:AA ratio levels (P trend<0.05). In the multivariable-adjusted analysis, the subjects in the first quartile of the serum EPA:AA ratio had a 1.93-fold (95% confidence interval, 1.15-3.22) greater risk of cancer death than those in the fourth quartile. Lower serum EPA concentrations were marginally associated with higher cancer mortality (P trend<0.11), but the serum DHA or AA concentrations and the serum DHA:AA ratio were not (all P trend>0.37). With regard to site-specific cancers, lower serum EPA:AA ratio was associated with a higher risk of death from liver cancer. However, no such associations were detected for deaths from other cancers. These findings suggest that decreased level of the serum EPA:AA ratio is a significant risk factor for cancer death in the general Japanese population. Copyright © 2017. Production and hosting by Elsevier B.V.

Intragastric Gelation of Heated Soy Protein Isolate-Alginate Mixtures and Its Effect on Sucrose Release.

PubMed

Huang, Zhaozhi; Gruen, Ingolf; Vardhanabhuti, Bongkosh

2018-06-15

The goal of our study was to investigate the effect of alginate on in vitro gastric digestion and sucrose release of soy protein isolate (SPI) in model beverages. Model beverages containing 5% w/w SPI, 0% to 0.20% w/w alginate, and 10% w/w sucrose were prepared by heating the mixtures at 85 °C for 30 min at pH 6.0 or 7.0. Characterizations of beverages included determination of zeta potential, particle size and rheological properties. Digestion patterns and sucrose release profiles were determined during 2 hr in vitro gastric digestion using SDS-PAGE and HPLC analysis, respectively. Increasing alginate concentration led to increased negative surface charge, particle size, as well as viscosity and pseudoplastic behavior; however, no phase separation was observed. SPI beverages formed intragastric gel during in vitro gastric digestion when the formulations contained alginate or at pH 6.0 without alginate. Formation of the intragastric gel led to delayed protein digestion and release of sucrose. Higher resistance to digestion and a slower sucrose release rate were exhibited at increased alginate concentration, and to a lesser extent, at pH 6.0. This suggests that electrostatic interaction between SPI and alginate that occurred when the beverages were under gastric condition could be responsible for the intragastric gelation. These results could potentially lead to the formulation of SPI beverages with functionality to lower postprandial glycemic response. The results could be used to design beverages or semi solid food products with altered digestion properties and lowered or slower glucose release. © 2018 Institute of Food Technologists®.

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

PubMed Central

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

2014-01-01

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

21 CFR 184.1610 - Potassium alginate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of...

21 CFR 582.7187 - Calcium alginate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7187...

21 CFR 582.7610 - Potassium alginate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7610...

21 CFR 582.7610 - Potassium alginate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7610...

21 CFR 582.7133 - Ammonium alginate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium alginate. 582.7133 Section 582.7133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7133...

21 CFR 184.1610 - Potassium alginate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of...

21 CFR 582.7187 - Calcium alginate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7187...

21 CFR 582.7133 - Ammonium alginate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium alginate. 582.7133 Section 582.7133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7133...

Evaluation of the diffusion coefficient for controlled release of oxytetracycline from alginate/chitosan/poly(ethylene glycol) microbeads in simulated gastrointestinal environments.

PubMed

Cruz, Maria C Pinto; Ravagnani, Sergio P; Brogna, Fabio M S; Campana, Sérgio P; Triviño, Galo Cardenas; Lisboa, Antonio C Luz; Mei, Lucia H Innocentini

2004-12-01

Diffusion studies of OTC (oxytetracycline) entrapped in microbeads of calcium alginate, calcium alginate coacervated with chitosan (of high, medium and low viscosity) and calcium alginate coacervated with chitosan of low viscosity, covered with PEG [poly(ethylene glycol) of molecular mass 2, 4.6 and 10 kDa, were carried out at 37+/-0.5 degrees C, in pH 7.4 and pH 1.2 buffer solutions - conditions similar to those found in the gastrointestinal system. The diffusion coefficient, or diffusivity (D), of OTC was calculated by equations provided by Crank [(1975) Mathematics in Diffusion, p. 85, Clarendon Press, Oxford] for diffusion, which follows Fick's [(1855) Ann. Physik (Leipzig) 170, 59] second law, considering the diffusion from the inner parts to the surface of the microbeads. The least-squares and the Newton-Raphson [Carnahan, Luther and Wilkes (1969) Applied Numerical Methods, p. 319, John Wiley & Sons, New York] methods were used to obtain the diffusion coefficients. The microbead swelling at pH 7.4 and OTC diffusion is classically Fickian, suggesting that the OTC transport, in this case, is controlled by the exchange rates of free water and relaxation of calcium alginate chains. In case of acid media, it was observed that the phenomenon did not follow Fick's law, owing, probably, to the high solubility of the OTC in this environment. It was possible to modulate the release rate of OTC in several types of microbeads. The presence of cracks formed during the process of drying the microbeads was observed by scanning electron microscopy.

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.

Culture of hESC-derived pancreatic progenitors in alginate-based scaffolds.

PubMed

Formo, Kjetil; Cho, Candy H-H; Vallier, Ludovic; Strand, Berit L

2015-12-01

The effect of alginate-based scaffolds with added basement membrane proteins on the in vitro development of hESC-derived pancreatic progenitors was investigated. Cell clusters were encapsulated in scaffolds containing the basement membrane proteins collagen IV, laminin, fibronectin, or extracellular matrix-derived peptides, and maintained in culture for up to 46 days. The cells remained viable throughout the experiment with no signs of central necrosis. Whereas nonencapsulated cells aggregated into larger clusters, some of which showed signs of morphological changes and tissue organization, the alginate matrix stabilized the cluster size and displayed more homogeneous cell morphologies, allowing culture for long periods of time. For all conditions tested, a stable or declining expression of insulin and PDX1 and an increase in glucagon and somatostatin over time indicated a progressive reduction in beta cell-related gene expression. Alginate scaffolds can provide a chemically defined, xeno-free and easily scalable alternative for culture of pancreatic progenitors. Although no increase in insulin and PDX1 gene expression after alginate-immobilized cell culture was seen in this study, further optimization of the matrix physicochemical and biological properties and of the medium composition may still be a relevant strategy to promote the stabilization or maturation of stem cell-derived beta cells. © 2015 Wiley Periodicals, Inc.

Oesophageal bioadhesion of sodium alginate suspensions: particle swelling and mucosal retention.

PubMed

Richardson, J Craig; Dettmar, Peter W; Hampson, Frank C; Melia, Colin D

2004-09-01

This paper describes a prospective bioadhesive liquid dosage form designed to specifically adhere to the oesophageal mucosa. It contains a swelling polymer, sodium alginate, suspended in a water-miscible vehicle and is activated by dilution with saliva to form an adherent layer of polymer on the mucosal surface. The swelling of alginate particles and the bioadhesion of 40% (w/w) sodium alginate suspensions were investigated in a range of vehicles: glycerol, propylene glycol, PEG 200 and PEG 400. Swelling of particles as a function of vehicle dilution with artificial saliva was quantified microscopically using 1,9-dimethyl methylene blue (DMMB) as a visualising agent. The minimum vehicle dilution to initiate swelling varied between vehicles: glycerol required 30% (w/w) dilution whereas PEG 400 required nearly 60% (w/w). Swelling commenced when the Hildebrand solubility parameter of the diluted vehicle was raised to 37 MPa(1/2). The bioadhesive properties of suspensions were examined by quantifying the amount of sodium alginate retained on oesophageal mucosa after washing in artificial saliva. Suspensions exhibited considerable mucoretention and strong correlations were obtained between mucosal retention, the minimum dilution to initiate swelling, and the vehicle Hildebrand solubility parameter. These relationships may allow predictive design of suspensions with specific mucoretentive properties, through judicious choice of vehicle characteristics.

Constitutive behavior of as-cast AA1050, AA3104, and AA5182

NASA Astrophysics Data System (ADS)

van Haaften, W. M.; Magnin, B.; Kool, W. H.; Katgerman, L.

2002-07-01

Recent thermomechanical modeling to calculate the stress field in industrially direct-chill (DC) cast-aluminum slabs has been successful, but lack of material data limits the accuracy of these calculations. Therefore, the constitutive behavior of three aluminum alloys (AA1050, AA3104, and AA5182) was determined in the as-cast condition using tensile tests at low strain rates and from room temperature to solidus temperature. The parameters of two constitutive equations, the extended Ludwik equation and a combination of the Sellars-Tegart equation with a hardening law, were determined. In order to study the effect of recovery, the constitutive behavior after prestraining at higher temperatures was also investigated. To evaluate the quantified constitutive equations, tensile tests were performed simulating the deformation and cooling history experienced by the material during casting. It is concluded that both constitutive equations perform well, but the combined hardening-Sellars-Tegart (HST) equation has temperature-independent parameters, which makes it easier to implement in a DC casting model. Further, the deformation history of the ingot should be taken into account for accurate stress calculations.

Negative Affect, Relapse, and Alcoholics Anonymous (AA): Does AA Work by Reducing Anger?*

PubMed Central

Kelly, John F.; Stout, Robert L.; Tonigan, J. Scott; Magill, Molly; Pagano, Maria E.

2010-01-01

Objective: Anger and other indices of negative affect have been implicated in a stress-induced pathway to relapse. The Alcoholics Anonymous (AA) literature states that reduction of anger is critical to recovery, yet this proposed mechanism has rarely been investigated. Using lagged, controlled hierarchical linear modeling analyses, this study investigated whether AA attendance mobilized changes in anger and whether such changes explained AA-related benefit. Method: Alcohol-dependent adults (N = 1,706) receiving treatment as part of a clinical trial were assessed at intake and at 3, 6, 9, 12, and 15 months. Results: Findings revealed substantially elevated levels of anger compared with the general population (98th percentile) that decreased over 15-month follow-up but remained high (89th percentile). AA attendance was associated with better drinking outcomes, and higher levels of anger were associated with heavier drinking. However, AA attendance was unrelated to changes in anger. Conclusions: Although support was not found for anger as a mediator, there was strong convergence between AA's explicit emphasis on anger and the present findings: Anger appears to be a serious, enduring problem related to relapse and heavy alcohol consumption. Methodological factors may have contributed to the lack of association between AA and anger, but results suggest that AA attendance alone may be insufficient to alleviate the suffering and alcohol-related risks specifically associated with anger. PMID:20409438

A smart bioconjugate of alginate and pectinase with unusual biological activity toward chitosan.

PubMed

Sardar, Meryam; Roy, Ipsita; Gupta, Munishwar N

2003-01-01

The commercial preparation of pectinase (Pectinex Ultra SP-L) was conjugated to alginate by noncovalent interactions by employing 1% alginate during the conjugation protocol. The optimum "immobilization efficiency" was 0.76. The pH optimum and the thermal stability of the enzyme remained unchanged upon conjugation with alginate. The soluble bioconjugate showed a 3-fold increase in V(max)/K(m) as compared to the free enzyme when the smart biocatalyst was used for chitosan hydrolysis. Time course hydrolysis of chitosan thus showed higher conversion of chitosan into reducing oligosaccharides/sugars. The smart bioconjugate could be reused five times without any detectable loss of chitosanase activity.

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

PubMed

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

2014-09-01

An effective cross-linking of alginate gel was made through reaction with calcium carbonate (CaCO3). We used human chondrocytes as a model cell to study the effects of cross-linking density. Three different pore size ranges of cross-linked alginate hydrogels were fabricated. The morphological, mechanical, and rheological properties of various alginate hydrogels were characterized and responses of biosynthesis of cells encapsulated in each gel to the variation in cross-linking density were investigated. Desired outer shape of structure was maintained when the alginate solution was cross-linked with the applied method. The properties of alginate hydrogel could be tailored through applying various concentrations of CaCO3. The rate of synthesized GAGs and collagens was significantly higher in human chondrocytes encapsulated in the smaller pore structure than that in the larger pore structure. The expression of chondrogenic markers, including collagen type II and aggrecan, was enhanced in the smaller pore structure. It was found that proper structural morphology is a critical factor to enhance the performance and tissue regeneration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and evaluation of functional alginate hydrogels based on click chemistry for drug delivery applications.

PubMed

García-Astrain, Clara; Avérous, Luc

2018-06-15

Environment-sensitive alginate-based hydrogels for drug delivery applications are receiving increasing attention. However, most work in this field involves traditional cross-linking strategies which led to hydrogels with poor long-term stability. Herein, a series of chemically cross-linked alginate hydrogels was synthesized via click chemistry using Diels-Alder reaction by reacting furan-modified alginate and bifunctional cross-linkers. Alginate was successfully functionalized with furfurylamine. Then, 3D architectures were synthesized with water-soluble bismaleimides. Different substitution degrees were achieved in order to study the effect of alginate modification and the cross-linking extent over the behaviour of the hydrogels. The ensuing hydrogels were analysed in terms of microstructure, swelling, structure modification and rheological behaviour. The materials response to external stimuli such as pH was also investigated, revealing a pulsatile behaviour in a large pH range (1-13) and a clear pH-dependent swelling. Finally, vanillin release studies were conducted to demonstrate the potential of these biobased materials for drug delivery applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of storage time of extended-pour and conventional alginate impressions on dimensional accuracy of casts.

PubMed

Rohanian, Ahmad; Ommati Shabestari, Ghasem; Zeighami, Somayeh; Samadi, Mohammad Javad; Shamshiri, Ahmad Reza

2014-11-01

Some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. The present study evaluated the effect of storage time on dimensional stability of three alginates: Hydrogum 5, Tropicalgin and Alginoplast. In this experimental in-vitro trial, a total of 90 alginate impressions were made from a Dentoform model using Hydrogum 5, Tropicalgin and Alginoplast alginates. The impressions were stored in a sealed plastic bag without a damp paper towel for 0, 24, 48, 72 and 120 hours and then poured with type III dental stone. Cross-arch (facial of 6 to facial of 6 on the opposite side) and antero-posterior (distal of right first molar to the ipsilateral central incisor) measurements were made with a digital caliper on the casts. Data were analyzed by two-way and one-way ANOVA and Tukey's post-hoc test (P<0.05). Alginate type and the pouring time significantly affected the dimensional stability of alginate impressions (both Ps<0.001). Pouring of Hydrogum 5 impressions can be delayed for up to 120 hours without significant dimensional changes. Alginoplast impressions may be poured after 72 hours, but Tropicalgin should be poured immediately and the storage time should not be more than 24 hours. Immediate pouring of alginate impressions provides the highest accuracy in reproducing the teeth and adjacent tissues; however, this study demonstrated that pouring may be delayed for up to five days using extended-pour (Hydrogum 5) alginates.

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.

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

Blood fatty acid composition of pregnant and nonpregnant Korean women: red cells may act as a reservoir of arachidonic acid and docosahexaenoic acid for utilization by the developing fetus.

PubMed

Ghebremeskel, K; Min, Y; Crawford, M A; Nam, J H; Kim, A; Koo, J N; Suzuki, H

2000-05-01

Relative fatty acid composition of plasma and red blood cell (RBC) choline phosphoglycerides (CPG), and RBC ethanolamine phosphoglycerides (EPG) of pregnant (n = 40) and nonpregnant, nonlactating (n = 40), healthy Korean women was compared. The two groups were of the same ethnic origin and comparable in age and parity. Levels of arachidonic (AA) and docosahexaenoic (DHA) acids were lower (P < 0.05) and palmitic and oleic acids higher (P < 0.0001) in plasma CPG of the pregnant women. Similarly, the RBC CPG and EPG of the pregnant women had lower AA and DHA (P < 0.05) and higher palmitic and oleic acids (P < 0.01). The reduction in DHA and total n-3 fatty acids in plasma CPG of the pregnant women was paralleled by an increase in docosatetraenoic (DTA) and docosapentaenoic (DPA) acids of the n-6 series and in DPA/DTA ratio. In the RBC phospholipids (CPG and EPG) of the pregnant women, DTA and DPA acids of the n-6 series and DPA/DTA ratio did not increase with the decrease of the n-3 metabolites (eicosapentaenoic acid, DPA, and DHA) and total n-3. Since pregnancy was the main identifiable variable between the two groups, the lower levels of AA and DHA in RBC CPG and EPG of the pregnant women suggest that the mothers were mobilizing membrane AA and DHA to meet the high fetal requirement for these nutrients. It may also suggest that RBC play a role as a potential store of AA and DHA and as a vehicle for the transport of these fatty acids from maternal circulation to the placenta to be utilized by the developing fetus.

Three-dimensional electrospun polycaprolactone (PCL)/alginate hybrid composite scaffolds.

PubMed

Kim, Min Seong; Kim, GeunHyung

2014-12-19

Micro/nanofibrous scaffolds have been used widely in biomedical applications because the micro/nano-scale fibres resemble natural extracellular matrix and the high surface-to-volume ratio encourages cellular activities (attachment and proliferation). However, poor mechanical properties, low controllability of various shapes and difficulties in obtaining controllable pore structure have been obstacles to their use in hard-tissue regeneration. To overcome these shortcomings, we suggest a new composite system, which uses a combination method of wet electrospinning, rapid prototyping and a physical punching process. Using the process, we obtained polycaprolactone (PCL)/alginate composite scaffolds, consisting of electrospun PCL/alginate fibres and micro-sized PCL struts, with mean pore sizes of 821 ± 55 μm. To show the feasibility of the scaffolds for hard-tissue regeneration, the scaffolds were assessed not only for physical properties, including hydrophilicity, water absorption, and tensile and compressive strength, but also in vitro cellular responses (cell viability and proliferation) and osteogenic differentiation (alkaline phosphatase (ALP) activity, and mineralisation) by culturing with pre-osteoblasts (MC3T3-E1 cells). With the reinforcing micro-sized PCL struts, the elastic modulus of the PCL/alginate scaffold was significantly improved versus a pure PCL scaffold. Additionally, due to the alginate component in the fibrous scaffold, they showed significantly enhanced hydrophilic behaviour, water absorption (∼8-fold) and significant biological activities (∼1.6-fold for cell viability at 7 days, ∼2.3-fold for ALP activity at 14 days and ∼6.4-fold for calcium mineralisation at 14 days) compared with those of a pure PCL fibrous scaffold. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

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

NASA Astrophysics Data System (ADS)

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

2016-07-01

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

Oesophageal bioadhesion of sodium alginate suspensions 2. Suspension behaviour on oesophageal mucosa.

PubMed

Richardson, J Craig; Dettmar, Peter W; Hampson, Frank C; Melia, Colin D

2005-01-01

Sodium alginate suspensions in a range of water miscible vehicles were investigated as novel bioadhesive liquids for targeting the oesophageal mucosa. Such a dosage form might be utilised to coat the oesophageal surface and provide a protective barrier against gastric reflux, or to deliver therapeutic agents site-specifically. Alginate suspensions swelled and formed an adherent viscous layer on contact with the mucosa. The swelling kinetics of alginate particles on the oesophageal surface was examined with respect to vehicle composition and related to the extent, duration and location of bioadhesion within the oesophagus. Mucosal retention was evaluated in two in vitro models utilising tissue immersion and a peristaltic tube. By varying the vehicle composition it was possible to modulate the rate of swelling of alginate particles on the mucosa and the mucosal retention of suspensions. Suspensions containing predominantly glycerol exhibited superior retention and were preferentially retained within the lower oesophagus. The propensity of these suspensions to rapidly swell on the mucosa and establish adhesive/cohesive bonds may explain their enhanced retention. The potential to control, through vehicle composition, the extent, duration and location of oesophageal retention could provide a useful tool for site targeting of viscous polymers to the oesophagus.

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

NASA Astrophysics Data System (ADS)

Asadi, Asadollah

2014-04-01

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

Fabrication of cationic chitin nanofiber/alginate composite materials.

PubMed

Sato, Koki; Tanaka, Kohei; Takata, Yusei; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

2016-10-01

We have already found that an amidinated chitin, which was prepared by the reaction of a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, was converted into an amidinium chitin bicarbonate with nanofiber morphology by CO2 gas bubbling and ultrasonic treatments in water. In this study, we performed the fabrication of composite materials of such cationic chitin nanofibers with an anionic polysaccharide, sodium alginate, by ion exchange. When the amidinium chitin bicarbonate nanofiber aqueous dispersion was added to an aqueous solution of sodium alginate, the composite material was agglomerated, which was isolated by centrifugation, filtration, and lyophilization, to form a manipulatable sheet. The morphology of the resulting sheet at nano-scale was evaluated by SEM measurement. Copyright © 2016 Elsevier B.V. All rights reserved.

Reductive dechlorination of carbon tetrachloride using buffered alkaline ascorbic acid.

PubMed

Lin, Ya-Ting; Liang, Chenju

2015-10-01

Alkaline ascorbic acid (AA) was recently discovered as a novel in-situ chemical reduction (ISCR) reagent for remediating chlorinated solvents in the subsurface. For this ISCR process, the maintenance of an alkaline pH is essential. This study investigated the possibility of the reduction of carbon tetrachloride (CT) using alkaline AA solution buffered by phosphate and by NaOH. The results indicated that CT was reduced by AA, and chloroform (CF) was a major byproduct at a phosphate buffered pH of 12. However, CT was completely reduced by AA in 2M NaOH without CF formation. In the presence of iron/soil minerals, iron could be reduced by AA and Fe(2+) tends to precipitate on the mineral surface to accelerate CT degradation. A simultaneous transfer of hydrogenolysis and dichloroelimination would occur under phosphate buffered pH 12. This implies that a high alkaline environment is a crucial factor for maintaining the dominant pathway of two electron transfer from dianionic AA to dehydroascorbic acid, and to undergo dichloroelimination of CT. Moreover, threonic acid and oxalic acid were identified to be the major AA decomposition products in alkaline solutions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Some distinguishable properties between acid-stable and neutral types of alpha-amylases from acid-producing koji.

PubMed

Suganuma, Toshihiko; Fujita, Kiyotaka; Kitahara, Kanefumi

2007-11-01

The highly humid climate of Japan facilitates the growth of various molds. Among these molds, Aspergillus oryzae is the most important and popular in Japan, and has been used as yellow-koji in producing many traditional fermented beverages and foods, such as Japanese sake, and soy sauce. Taka-amylase A (TAA), a major enzyme produced by the mold, is well known worldwide to be a leading enzyme for industrial utilization and academic study, since many extensive studies have been carried out with TAA. In southern Kyushu, the other koji's of citric acid-producing molds have often been used, such as in the production of a traditional distilled liquor of shochu. The koji molds black-koji and white-koji produce two types of alpha-amylase, namely, acid-stable (AA) and common neutral (NA). The latter enzyme is enzymatically and genetically similar to TAA. In this review, we investigate AA from three molds, Aspergillus niger, A. kawachii and A. awamori, and the yeast Cryptococcus sp. regarding the distinguishable properties between AA and NA. (i) The N-terminus amino acid sequences of AA determined by molecular cloning started with the sequence of L-S-A-, whereas those of NA started with A-T-P-. (ii) Most of the full sequences of AA were composed of, besides a core catalytic domain, an extra domain of a hinge region and a carbohydrate binding domain, which could be responsible for raw-starch-digestibility. The AA from A. niger has no exceptionally extra domain, similarly to NA. (iii) Simple methods for distinguishing AA from NA using CNP-alpha-G3 and G5 as substrates were developed by our group. (iv) The number of subsite in AA on the basis of its cleavage pattern of maltooligosaccharides was estimated to be five, which differs from that of TAA, 7-9. AA has many advantages in industrial applications, such as its acid-stability, thermostability, and raw-starch digesting properties.

Photo-crosslinked alginate hydrogels support enhanced matrix accumulation by nucleus pulposus cells in vivo.

PubMed

Chou, A I; Akintoye, S O; Nicoll, S B

2009-10-01

Intervertebral disc (IVD) degeneration is a major health concern in the United States. Replacement of the nucleus pulposus (NP) with injectable biomaterials represents a potential treatment strategy for IVD degeneration. The objective of this study was to characterize the extracellular matrix (ECM) assembly and functional properties of NP cell-encapsulated, photo-crosslinked alginate hydrogels in comparison to ionically crosslinked alginate constructs. Methacrylated alginate was synthesized by esterification of hydroxyl groups with methacrylic anhydride. Bovine NP cells were encapsulated in alginate hydrogels by ionic crosslinking using CaCl(2) or through photo-crosslinking upon exposure to long-wave UV light in the presence of a photoinitiator. The hydrogels were evaluated in vitro by gross and histological analysis and in vivo using a murine subcutaneous pouch model. In vivo samples were analyzed for gene expression, ECM localization and accumulation, and equilibrium mechanical properties. Ionically crosslinked hydrogels exhibited inferior proteoglycan accumulation in vitro and were unable to maintain structural integrity in vivo. In further studies, photo-crosslinked alginate hydrogels were implanted for up to 8 weeks to examine NP tissue formation. Photo-crosslinked hydrogels displayed temporal increases in gene expression and assembly of type II collagen and proteoglycans. Additionally, hydrogels remained intact over the duration of the study and the equilibrium Young's modulus increased from 1.24+/-0.09 kPa to 4.31+/-1.39 kPa, indicating the formation of functional matrix with properties comparable to those of the native NP. These findings support the use of photo-crosslinked alginate hydrogels as biomaterial scaffolds for NP replacement.

The study of the structural properties of very low viscosity sodium alginate by small-angle neutron scattering

NASA Astrophysics Data System (ADS)

Badita, C. R.; Aranghel, D.; Radulescu, A.; Anitas, E. M.

2016-03-01

Sodium alginate is a linear polymer extract from brown algae and it is used in the biomedical, food, cosmetics and pharmaceutical industries as solution property modifiers and gelling agents. But despite the extensive studies of the alginate gelation process, still some fundamental questions remain unresolved. The fractal behavior of very low viscosity sodium alginate solutions and their influence on the critical gelation of alginate induced by Ca2+ ions were investigated using Small-Angle Neutron Scattering (SANS) measurements. SANS data are interpreted using both standard linear plots and the Beaucage model. The scattering intensity is dependent by alginate concentration and Ca2+ concentration. From a critical concentration of 1.0 % w/w our polymer swelled forming spherical structures with rough surfaces. Also the addition of the salt induces the collapse and the appearance of the aggregation and clusters formation.

Renal Liver-Type Fatty Acid Binding Protein (L-FABP) Attenuates Acute Kidney Injury in Aristolochic Acid Nephrotoxicity

PubMed Central

Matsui, Katsuomi; Kamijo-Ikemorif, Atsuko; Sugaya, Takeshi; Yasuda, Takashi; Kimura, Kenjiro

2011-01-01

Injection of aristolochic acid (AA) in mice causes AA-induced nephrotoxicity, in which oxidative stress contributes to development of tubulointerstitial damage (TID). Liver-type fatty acid binding protein (L-FABP) is expressed in human proximal tubules and has an endogenous antioxidative function. The renoprotection of renal L-FABP was examined in a model of AA-induced nephrotoxicity. Established human L-FABP (hL-FABP) transgenic (Tg) mice and wild-type (WT) mice were treated with AA for up to 5 days. Mice were sacrificed on days 1, 3, and 5 after the start of AA injection. Although mouse L-FABP was not expressed in proximal tubules of WT mice, hL-FABP was expressed in proximal tubules of Tg mice. The expression of renal hL-FABP was significantly increased in Tg mice administered AA (Tg-AA), compared with the control (saline-treated Tg mice). In WT-AA mice, there was high urinary excretion of Nε-(hexanoyl)-lysine, the production of heme oxygenase-1 and receptor for advanced glycation end products increased, and TID was provoked. In contrast, renal hL-FABP in Tg-AA mice suppressed production of Nε-(hexanoyl)lysine, heme oxygenase-1, and receptor for advanced glycation end products. Renal dysfunction was significantly milder in Tg-AA mice than in WT-AA mice. The degree of TID was significantly attenuated in Tg-AA mice, compared with WT-AA. In conclusion, renal hL-FABP reduced the oxidative stress in AA-induced nephrotoxicity and attenuated TID. PMID:21356355

A computational modeling approach for the characterization of mechanical properties of 3D alginate tissue scaffolds.

PubMed

Nair, K; Yan, K C; Sun, W

2008-01-01

Scaffold guided tissue engineering is an innovative approach wherein cells are seeded onto biocompatible and biodegradable materials to form 3-dimensional (3D) constructs that, when implanted in the body facilitate the regeneration of tissue. Tissue scaffolds act as artificial extracellular matrix providing the environment conducive for tissue growth. Characterization of scaffold properties is necessary to understand better the underlying processes involved in controlling cell behavior and formation of functional tissue. We report a computational modeling approach to characterize mechanical properties of 3D gellike biomaterial, specifically, 3D alginate scaffold encapsulated with cells. Alginate inherent nonlinearity and variations arising from minute changes in its concentration and viscosity make experimental evaluation of its mechanical properties a challenging and time consuming task. We developed an in silico model to determine the stress-strain relationship of alginate based scaffolds from experimental data. In particular, we compared the Ogden hyperelastic model to other hyperelastic material models and determined that this model was the most suitable to characterize the nonlinear behavior of alginate. We further propose a mathematical model that represents the alginate material constants in Ogden model as a function of concentrations and viscosity. This study demonstrates the model capability to predict mechanical properties of 3D alginate scaffolds.

Culture of C3A cells in alginate beads for fluidized bed bioartificial liver.

PubMed

Kinasiewicz, A; Gautier, A; Lewinska, D; Bukowski, J; Legallais, C; Weryński, A

2007-11-01

Extracorporeal bioartificial liver has been designed to sustain the detoxification and synthetic function of the failed liver in patients suffering from acute liver failure until the time of liver allotransplantation or regeneration of their own. A fluidized bed, bioartificial liver improves the mass transfer velocity between the medium and the hepatocytes. Detoxification functions of the liver could be replaced by completely artificial systems, but the synthetic functions of hepatocytes may be obtained only by metabolically active cells. The aim of our study was to investigate the influence of C3A cell culture in alginate beads on synthetic function in a fluidized bed, bioartificial liver. Cells in alginate beads were prepared using an electrostatic droplet generator of our own design using low-viscosity alginate. Beads were cultured for 24 hours then 7 days in static conditions and then 24 hours of fluidization in the bioreactor to assess albumin production. We observed significantly increased albumin production by C3A cells entrapped in alginate beads during static culture. Fluidization increased albumin production compared with static culture. Fluidization performed after 7 days of static culture resulted in a significant increase in albumin synthesis. In conclusion, static culture of alginate beads hosting hepatic cells facilitates restoration of cell function.

Chitosan and alginate types of bio-membrane in fuel cell application: An overview

NASA Astrophysics Data System (ADS)

Shaari, N.; Kamarudin, S. K.

2015-09-01

The major problems of polymer electrolyte membrane fuel cell technology that need to be highlighted are fuel crossovers (e.g., methanol or hydrogen leaking across fuel cell membranes), CO poisoning, low durability, and high cost. Chitosan and alginate-based biopolymer membranes have recently been used to solve these problems with promising results. Current research in biopolymer membrane materials and systems has focused on the following: 1) the development of novel and efficient biopolymer materials; and 2) increasing the processing capacity of membrane operations. Consequently, chitosan and alginate-based biopolymers seek to enhance fuel cell performance by improving proton conductivity, membrane durability, and reducing fuel crossover and electro-osmotic drag. There are four groups of chitosan-based membranes (categorized according to their reaction and preparation): self-cross-linked and salt-complexed chitosans, chitosan-based polymer blends, chitosan/inorganic filler composites, and chitosan/polymer composites. There are only three alginate-based membranes that have been synthesized for fuel cell application. This work aims to review the state-of-the-art in the growth of chitosan and alginate-based biopolymer membranes for fuel cell applications.

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

PubMed

Schmitt, Andreas; Rödel, Philipp; Anamur, Cihad; Seeliger, Claudine; Imhoff, Andreas B; Herbst, Elmar; Vogt, Stephan; van Griensven, Martijn; Winter, Gerhard; Engert, Julia

2015-01-01

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

Longitudinal study of experimental induction of AA amyloidosis in mice seeded with homologous and heterologous AA fibrils.

PubMed

Muhammad, Naeem; Murakami, Tomoaki; Inoshima, Yasuo; Ishiguro, Naotaka

2016-09-01

To investigate pathogenesis and kinetics of experimentally induced murine AA amyloidosis seeded with homologous (murine) and heterologous (bovine) AA fibrils. Experimental AA amyloidosis was induced by administration of inflammatory stimulus and preformed AA fibrils to a total of 111 female C57/Black mice. In this longitudinal study, heterologous (bovine) as well as homologous (murine) AA fibrils were injected intraperitoneally to mice in various combinations. Re-stimulation was done at 120 or 300 days post first inoculation. To analyze the intensity of amyloid depositions in mice organs, immunohistochemical techniques and image J software were used. Assessment of cytokines level in sera was done using a Mouse Th1/Th2/Th17 Cytokine CBA Kit. Incidence and severity of AA amyloidosis were quite low in mice inoculated with heterologous bovine AA fibrils than homologous murine one. Homologous AA fibrils administration at first and second inoculation caused maximum amount of amyloid depositions and severe systemic form of amyloidosis. Increase in the level of pro-inflammatory cytokine IL-6 was observed after first inoculation, while second inoculation caused a further increase in the level of anti-inflammatory cytokine IL-10. AA amyloidosis can be induced by heterologous as well as homologous AA fibrils. Severity of AA amyloidosis induced with homologous AA fibrils is higher compared to heterologous AA fibrils.

Sulindac loaded alginate beads for a mucoprotective and controlled drug release.

PubMed

Yegin, Betül Arica; Moulari, Brice; Durlu-Kandilci, N Tugba; Korkusuz, Petek; Pellequer, Yann; Lamprecht, Alf

2007-06-01

Ionotropic gelation was used to entrap sulindac into calcium alginate beads as a potential drug carrier for the oral delivery of this anti-inflammatory drug. Beads were investigated in vitro for a possible sustained drug release and their use in vivo as a gastroprotective system for sulindac. Process parameters such as the polymer concentration, polymer/drug ratio, and different needle diameter were analysed for their influences on the bead properties. Size augmented with increasing needle diameter (0.9 mm needle: 1.28 to 1.44 mm; 0.45 mm needle: 1.04 to 1.07 mm) due to changes in droplet size as well as droplet viscosity. Yields varied between 87% and 98% while sulindac encapsulation efficiencies of about 88% and 94% were slightly increasing with higher alginate concentrations. Drug release profiles exhibited a complete release for all formulations within 4 hours with a faster release for smaller beads. Sulindac loaded alginate beads led to a significant reduction of macroscopic histological damage in the stomach and duodenum in mice. Similarly, microscopic analyses of the mucosal damage demonstrated a significant mucoprotective effect of all bead formulation compared to the free drug. The present alginate formulations exhibit promising properties of a controlled release form for sulindac; meanwhile they provide a distinct tissue protection in the stomach and duodenum.

Effect of Storage Time of Extended-Pour and Conventional Alginate Impressions on Dimensional Accuracy of Casts

PubMed Central

Rohanian, Ahmad; Ommati Shabestari, Ghasem; Zeighami, Somayeh; Samadi, Mohammad Javad; Shamshiri, Ahmad Reza

2014-01-01

Objectives: Some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. The present study evaluated the effect of storage time on dimensional stability of three alginates: Hydrogum 5, Tropicalgin and Alginoplast. Materials and Methods: In this experimental in-vitro trial, a total of 90 alginate impressions were made from a Dentoform model using Hydrogum 5, Tropicalgin and Alginoplast alginates. The impressions were stored in a sealed plastic bag without a damp paper towel for 0, 24, 48, 72 and 120 hours and then poured with type III dental stone. Cross-arch (facial of 6 to facial of 6 on the opposite side) and antero-posterior (distal of right first molar to the ipsilateral central incisor) measurements were made with a digital caliper on the casts. Data were analyzed by two-way and one-way ANOVA and Tukey’s post-hoc test (P<0.05). Results: Alginate type and the pouring time significantly affected the dimensional stability of alginate impressions (both Ps<0.001). Pouring of Hydrogum 5 impressions can be delayed for up to 120 hours without significant dimensional changes. Alginoplast impressions may be poured after 72 hours, but Tropicalgin should be poured immediately and the storage time should not be more than 24 hours. Conclusion: Immediate pouring of alginate impressions provides the highest accuracy in reproducing the teeth and adjacent tissues; however, this study demonstrated that pouring may be delayed for up to five days using extended-pour (Hydrogum 5) alginates. PMID:25628695

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

PubMed Central

Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

2016-01-01

Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

Modification of pH Conferring Virucidal Activity on Dental Alginates

PubMed Central

Nallamuthu, Navina; Braden, Michael; Oxford, John; Williams, David; Patel, Mangala

2015-01-01

To formulate an alginate dental impression material with virucidal properties, experimental alginate dental impression materials were developed and the formulations adjusted in order to study the effect on pH profiles during setting. Commercially available materials served as a comparison. Eight experimental materials were tested for antiviral activity against Herpes Simplex Virus type 1 (HSV-1). Changing the amount of magnesium oxide (MgO) used in the experimental formulations had a marked effect on pH. Increasing MgO concentration corresponded with increased pH values. All experimental materials brought about viral log reductions ranging between 0.5 and 4.0 over a period of 4 h. The material with the lowest pH was the most effective. The current work highlights the very important role of MgO in controlling pH profiles. This knowledge has been applied to the formulation of experimental alginates; where materials with pH values of approximately 4.2–4.4 are able to achieve a significant log reduction when assayed against HSV-1. PMID:28788042

Production and characterization of the healthy brown rice milk with sodium alginate addition from brown algae Sargassum binderi as emulsifier

NASA Astrophysics Data System (ADS)

Latifah, R. N.; Warganegara, F. M.

2018-03-01

Brown rice milk, a plant milk, is potential to cure beriberi disease. Alginate was used as an emulsifier and increased the nutrition of brown rice milk. Alginate from Sargassum binderi was extracted by nonacidic treatment. The yield of alginate was 6.25 %. The moisture and water content of alginate were 18.27 % and 12.2 %, respectively. The density and viscosity of 0.1 % alginates in aqueous solution were 1.007 g·mL-1 and 7.651 × 10-3 kg·m-1s-1, respectively. The characteristics peaks of alginate appeared at 3,477; 1,633 and 1,419 cm-1, corresponding to hydroxyl (OH), carbonyl (C=O) and carboxyl (COOH), respectively. The best composition of alginate addition in brown rice milk was 0.2 %. The viscosity of the 0.2 % alginate in brown rice milk was 1.206 × 10-2 kg·m-1s-1 and showed a texture of small particle with closer spaces between the particles. The addition of alginate in brown rice milk also inhibited the process of sedimentation of milk which showed in the first order. The nutrition composition of the best brown rice milk was 40.21 mg·mL-1 carbohydrate; 1.3 mg·mL-1 protein; 0.158 mg·mL-1 fat and 13.1 mg·mL-1 total dietary fiber.

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

Transcriptome analysis revealed anti-obesity effects of the Sodium Alginate in high-fat diet -induced obese mice.

PubMed

Wang, Xiong; Liu, Fang; Gao, Yuan; Xue, Chang-Hu; Li, Robert W; Tang, Qing-Juan

2018-04-10

Human obesity and overweight, caused by accumulated of fat, is the most commonly phenomenon from all over the world, especially in Western countries and Chinese mainland during the past three decades. Sodium Alginate, a polysaccharide extracted from brown seaweeds, has been proved its strong ability on body weight loss and anti-inflammatory response. However, no studies have been explored the effects of Sodium Alginate on colonic transcriptome, especially in obese individuals. Therefore, the current study was designed to detect whether Sodium Alginate could remit obesity and ease chronic metabolism disease through strengthening the bio-functionality of the lower intestine, particularly in colon. The data showed after Sodium Alginate gavaged for four weeks, the body weight, fat accumulation, triglyceride and total cholesterol were ameliorated in high fat diet induced obese mice. Sodium Alginate also improved the blood glucose level and lipopolysaccharides in serum. Furthermore, data from RNA sequence indicated that there were significantly changes in several genes, which involved in lipid metabolism and carbohydrate metabolism. In conclusion, these results suggested that Sodium Alginate could effectively suppress obesity and obesity related metabolic syndromes, due to the colonic transcriptome changes. Copyright © 2018. Published by Elsevier B.V.

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.

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.

The study of the structural properties of very low viscosity sodium alginate by small-angle neutron scattering

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

Badita, C. R., E-mail: ramona@tandem.nipne.ro; University of Bucharest, Faculty of Physics, Atomiştilor 405, CP MG - 11, RO – 077125, Bucharest-Magurele; Aranghel, D., E-mail: daranghe@nipne.ro

2016-03-25

Sodium alginate is a linear polymer extract from brown algae and it is used in the biomedical, food, cosmetics and pharmaceutical industries as solution property modifiers and gelling agents. But despite the extensive studies of the alginate gelation process, still some fundamental questions remain unresolved. The fractal behavior of very low viscosity sodium alginate solutions and their influence on the critical gelation of alginate induced by Ca{sup 2+} ions were investigated using Small-Angle Neutron Scattering (SANS) measurements. SANS data are interpreted using both standard linear plots and the Beaucage model. The scattering intensity is dependent by alginate concentration and Ca{supmore » 2+} concentration. From a critical concentration of 1.0 % w/w our polymer swelled forming spherical structures with rough surfaces. Also the addition of the salt induces the collapse and the appearance of the aggregation and clusters formation.« less

Site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance substrate specificity towards maltodextrin for enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G).

PubMed

Han, Ruizhi; Liu, Long; Shin, Hyun-dong; Chen, Rachel R; Du, Guocheng; Chen, Jian

2013-07-01

In this work, the site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase towards maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) by CGTase. When using maltodextrin as glycosyl donor, four mutants K47F (lysine→ phenylalanine), K47L (lysine→ leucine), K47V (lysine→ valine) and K47W (lysine→ tryptophan) showed higher AA-2G yield as compared with that produced by the wild-type CGTase. The transformation conditions (temperature, pH and the mass ratio of L-ascorbic acid to maltodextrin) were optimized and the highest titer of AA-2G produced by the mutant K47L could reach 1.97 g/l, which was 64.2% higher than that (1.20 g/l) produced by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, the four mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. The mechanism responsible for the enhanced substrate specificity was further explored by structure modeling and it was indicated that the enhancement of maltodextrin specificity may be due to the short residue chain and the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. Here the obtained mutant CGTases, especially the K47L, has a great potential in the production of AA-2G with maltodextrin as a cheap and easily soluble substrate.

Effects of process variables on the encapsulation of oil in ca-alginate capsules using an inverse gelation technique.

PubMed

Abang, Sariah; Chan, Eng-Seng; Poncelet, Denis

2012-01-01

The objective of this study was to investigate the effects of process variables on the encapsulation of oil in a calcium alginate membrane using an inverse gelation technique. A dispersion of calcium chloride solution in sunflower oil (water-in-oil emulsion) was added dropwise to the alginate solution. The migration of calcium ions to the alginate solution initiates the formation of a ca-alginate membrane around the emulsion droplets. The membrane thickness of wet capsules and the elastic modulus of dry capsules increased following first-order kinetics with an increasing curing time. An increase in the calcium chloride concentration increased the membrane thickness of wet capsules and the elastic modulus of dry capsules. An increase in the alginate concentration decreased the mean diameter of wet capsules but increased the elastic modulus of dry capsules.

Ancient acquisition of "alginate utilization loci" by human gut microbiota.

PubMed

Mathieu, Sophie; Touvrey-Loiodice, Mélanie; Poulet, Laurent; Drouillard, Sophie; Vincentelli, Renaud; Henrissat, Bernard; Skjåk-Bræk, Gudmund; Helbert, William

2018-05-23

In bacteria from the phylum Bacteroidetes, the genes coding for enzymes involved in polysaccharide degradation are often colocalized and coregulated in so-called "polysaccharide utilization loci" (PULs). PULs dedicated to the degradation of marine polysaccharides (e.g. laminaran, ulvan, alginate and porphyran) have been characterized in marine bacteria. Interestingly, the gut microbiome of Japanese individuals acquired, by lateral transfer from marine bacteria, the genes involved in the breakdown of porphyran, the cell wall polysaccharide of the red seaweed used in maki. Sequence similarity analyses predict that the human gut microbiome also encodes enzymes for the degradation of alginate, the main cell wall polysaccharide of brown algae. We undertook the functional characterization of diverse polysaccharide lyases from family PL17, frequently found in marine bacteria as well as those of human gut bacteria. We demonstrate here that this family is polyspecific. Our phylogenetic analysis of family PL17 reveals that all alginate lyases, which have all the same specificity and mode of action, cluster together in a very distinct subfamily. The alginate lyases found in human gut bacteria group together in a single clade which is rooted deeply in the PL17 tree. These enzymes were found in PULs containing PL6 enzymes, which also clustered together in the phylogenetic tree of PL6. Together, biochemical and bioinformatics analyses suggest that acquisition of this system appears ancient and, because only traces of two successful transfers were detected upon inspection of PL6 and PL17 families, the pace of acquisition of marine polysaccharide degradation system is probably very slow.

Synthesis and characterization of agricultural controllable humic acid superabsorbent.

PubMed

Gao, Lijuan; Wang, Shiqiang; Zhao, Xuefei

2013-12-01

Humic acid superabsorbent polymer (P(AA/AM-HA)) and superabsorbent polymer (P(AA/AM)) were synthesized by aqueous solution polymerization method using acrylic acid (AA), acrylamide (AM) and humic acid (HA) as raw material. The effects of N,N'-methylenebisacrylamide (MBA) crosslinking agent, potassium peroxydisulfate (KPS) initiator, reaction temperature, HA content, ratio of AA to AM, concentration of monomer and neutralization of AA on water absorption were investigated. Absorption and desorption ratios of nitrogen fertilizer and phosphate fertilizer were also investigated by determination of absorption and desorption ratio of NH4(+), PO4(3-) on P(AA/AM-HA) and P(AA/AM). The P(AA/AM-HA) and P(AA/AM) were characterized by Fourier translation infrared spectroscopy, biological photomicroscope and scanning electron microscopy (SEM). The optimal conditions obtained were as follows: the weight ratio of MBA to AA and AM was 0.003; the weight ratio of KPS to AA and AM was 0.008; the weight ratio of HA to AA was 0.1; the mole ratio of AM to AA is 0.1; the mole ratio of NaOH to AA is 0.9; the reaction temperature was 60°C. P(AA/AM-HA) synthesized under optimal conditions, has a good saline tolerance, its water absorbency in distilled water and 0.9 wt.% saline solution is 1180 g/g and 110 g/g, respectively. P(AA/AM-HA) achieves half saturation in 6.5 min. P(AA/AM-HA) is superior to P(AA/AM) on absorption of NH4(+), PO4(3-). The SEM micrograph of P(AA/AM-HA) shows a fine alveolate structure. The biological optical microscope micrograph of P(AA/AM-HA) shows a network structure. Graft polymerization between P(AA/AM) and HA was demonstrated by infrared spectrum. The P(AA/AM-HA) superabsorbent has better absorbing ability of water and fertilizer, electrolytic tolerance and fewer cost than P(AA/AM) superabsorbent. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Amino acid supplementation alters bone metabolism during simulated weightlessness

NASA Technical Reports Server (NTRS)

Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

2005-01-01

High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

Lifting bloody footwear impressions using alginate casts followed by chemical enhancement.

PubMed

Wiesner, Sarena; Izraeli, Elad; Shor, Yaron; Domb, Avi

2013-05-01

A method for lifting bloody footwear impressions using alginate casts and enhancing the lifted impressions with amido black is presented. On rough or dark substrates, background interferences may conceal significant details of footwear impressions. Illumination with alternative light sources and chemically enhancing the bloody footwear impressions may reveal additional details, but sometimes, lifting footwear impressions prior to enhancing is the only way to expose hidden details (by using blood reagents not adequate on the original). Several cast formulations were tested for lifting the footwear impressions. The best results were achieved using Aroma fine®. Enhancement of the footwear impressions was attempted with several reagents prior to lifting, during the casting process, and on the lifted footwear impressions. Applying amido black to footwear impressions lifted with alginate produced the sharpest and most detailed footwear impressions. Alginate castings followed by chemical enhancement with amido black may produce high-quality footwear impressions for comparison. © 2013 American Academy of Forensic Sciences.

Uptake and conversion of D-amino acids in Arabidopsis thaliana.

PubMed

Gördes, Dirk; Kolukisaoglu, Üner; Thurow, Kerstin

2011-02-01

The D-enantiomers of proteinogenic amino acids fulfill essential functions in bacteria, fungi and animals. Just in the plant kingdom, the metabolism and role of D-amino acids (D-AAs) still remains unclear, although plants have to cope with significant amounts of these compounds from microbial decay in the rhizosphere. To fill this gap of knowledge, we tested the inhibitory effects of D-AAs on plant growth and established a method to quantitate 16 out of 19 proteinogenic amino acids and their D-enantiomers in plant tissue extracts. Therefore, the amino acids in the extracts were derivatized with Marfey's reagent and separated by HPLC-MS. We used two ecotypes (Col-0 and C24) and a mutant (lht1) of the model plant Arabidopsis thaliana to determine the influence and fate of exogenously applied D-AAs. All of them were found in high concentrations in the plant extracts after application, even in lht1, which points to additional transporters facilitating the import of D-AAs. The addition of particular amino acids (D-Trp, D-Phe, D-Met and D-His) led to the accumulation of the corresponding L-amino acid. In almost all cases, the application of a D-AA resulted in the accumulation of D-Ala and D-Glu. The presented results indicate that soil borne D-AAs can actively be taken up and metabolized via central metabolic routes.

Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

NASA Astrophysics Data System (ADS)

Kaisheva, N. Sh.; Kaishev, A. Sh.

2015-07-01

The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.