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Alginic acid

Xiaoyan Zhu, Xiangqian Li, Hao Shi, Jia Zhou, Zhongbiao Tan, Mengdi Yuan, Peng Yao, Xiaoyan Liu
Alginate lyases show great potential for industrial and medicinal applications, especially as an attractive biocatalyst for the production of oligosaccharides with special bioactivities. A novel alginate lyase, AlyH1, from the marine bacterium Vibrio furnissii H1, which has been newly isolated from rotten seaweed, was purified and characterized. The purified enzyme showed the specific activity of 2.40 U/mg. Its molecular mass was 35.8 kDa. The optimal temperature and pH were 40 °C and pH 7.5, respectively...
January 15, 2018: Marine Drugs
Xin Xu, Xiaofeng Wang, Wei Luo, Qihong Qian, Qian Li, Baosan Han, Yulin Li
In this report, biocompatible nanogels with multi cell-responsiveness (thermo-, pH- and reduction) were fabricated by in situ cross-linking of alginate (AG) using cystamine (Cys) as a cross-linker through an emulsion approach, in the presence of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM). The AG/PNIPAM nanogels exhibited an abrupt swelling upon temperature increase from 37 to 25 °C under physiological conditions (497 ± 258 nm at 29 °C and 147 ± 48 nm at 37 °C). The nanogels were easily taken up by cancer cells at high temperature, where temperature variation could induce toxicity against cancer cells...
December 28, 2017: Colloids and Surfaces. B, Biointerfaces
Elham Arkan, Abbas Hemati Azandaryani, Pouran Moradipour, Leila Behbood
BACKGROUND: Biopolymers based materials (polysaccharides, lipids, proteins, and nucleic acids) are one of the basic resources in bio-engineering sciences because of desirable features. Moreover, nanobiotechnology innovates nanomaterial and associated technique in nano medicine (drug delivery and tissue engineering). METHODS: In the nano-medicine, fibers are introduced as a successful biomimetic extracellular matrix scaffolds and drug carrier systems. Electrospinning as a simple and cost-effective technique is used to design nanofibers...
January 12, 2018: Current Pharmaceutical Biotechnology
Martha L López-Moreno, Yarilyn Cedeño-Mattei, Sonia Janet Bailón-Ruiz, Edgar Vazquez-Nuñez, José A Hernandez-Viezcas, Oscar Juan Perales-Pérez, Guadalupe De la Rosa, José R Peralta-Videa, Jorge L Gardea-Torresdey
The application of nanomaterials (NMs) depends on several characteristics, including polydispersity, shape, surface charge, and composition, among others. However, the specific surface properties of bare NMs induce aggregation, reducing their utilization. Thus, different surface coverages have been developed to avoid or minimize NMs aggregation, making them more stable for the envisioned applications. Carbon-based NMs are usually coated with metals, while metal-based NMs are coated with natural organic compounds including chitosan, dextran, alginate, or citric acid...
December 25, 2017: Journal of Hazardous Materials
Chengcheng Zhu, Rui Yang, Xiaobin Hua, Hong Chen, Jumei Xu, Rile Wu, Lian Cen
A highly stretchable hyaluronic acid (HA)/sodium alginate (SA) hydrogel was developed in this study based on an interpenetrating polymer network. HA/SA hydrogels were prepared by mixing two polysaccharides followed by covalent crosslinking via epoxy groups on HA molecules and ionic crosslinking via divalent ions on SA chains sequentially. The effect of HA/SA ratio on the pore size and distribution, swelling ratio, elongation and rheological properties as well as protein loading and release properties of HA/SA hydrogels was explored...
January 10, 2018: Journal of Biomaterials Science. Polymer Edition
Shimpo Aoki, Mao Fujii, Toshinori Fujie, Keisuke Nishiwaki, Hiromi Miyazaki, Daizoh Saitoh, Shinji Takeoka, Tomoharu Kiyosawa, Manabu Kinoshita
Although human recombinant basic fibroblast growth factor (bFGF) is widely used for wound healing, daily treatment with bFGF is required because of its short half-life. An effective controlled-release system of bFGF is therefore desired in clinical settings. To investigate the efficacy of a bFGF-loaded nanosheet for wound healing, focusing on the controlled-release of bFGF, bFGF-loaded poly lactic-co-glycolic acid (PGLA) nanosheets were developed, and their in vitro release profile of bFGF and their in vivo efficacy for wound healing were examined...
January 8, 2018: Wound Repair and Regeneration
Armin Mooranian, Rebecca Negrulj, Ryu Takechi, John Mamo, Hesham Al-Sallami, Hani Al-Salami
Probucol (PB) is an hypolipidaemic drug with potential antidiabetic effects. We showed recently using in vitro studies that when PB was incorporated with stabilising lipophilic bile acids and microencapsulated using the polymer sodium alginate, the microcapsules showed good stability but poor and irregular PB release. This suggests that PB microcapsules may exhibit better release profile and hence better absorption, if more hydrophilic bile acids were used, such as ursodeoxycholic acid (UDCA). Accordingly, this study aimed to produce PB-UDCA microcapsules and examine PB absorption and antidiabetic effects in our mouse-model of insulin-resistance and diabetes (fed high-fat diet; HFD)...
January 8, 2018: Drug Delivery and Translational Research
Ying Shao, Chunhua Wu, Tiantian Wu, Shiguo Chen, Tian Ding, Xingqian Ye, Yaqin Hu
Silver nanoparticles (AgNPs) were synthesized by a new 'green chemistry' method that uses sodium alginate (Na-Alg) and ascorbic acid (Vc) as the stabilizing and reducing agents, respectively. A possible mechanism involved in the reduction and stabilization of nanoparticles was investigated. The effect of reaction conditions such as pH, the addition of AgNO3 and Vc, ultrasonication treatments on the synthesis of AgNPs was investigated. The formation of AgNPs was confirmed by UV-vis spectroscopy and characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD)...
January 4, 2018: International Journal of Biological Macromolecules
Mokhamad Nur, Todor Vasiljevic
Nanoparticles or microparticles created by physical complexation between two polyelectrolytes may have a prospective use as an excipient for oral insulin administration. Natural polymers such as tragacanth, alginate, dextran, pullulan, hyaluronic acid, gelatin and chitosan can be potential candidates for this purpose. In this research, insulin particles were prepared by the inclusion of insulin into a tragacanth hydrogel. The effect of the pH and concentration relationship involving polyelectrolytes offering individual particle size and zeta potential was assessed by zetasizer and scanning electron microscopy (SEM)...
January 5, 2018: Materials
Detao Qin, Zhaoyang Liu, Zhi Liu, Hongwei Bai, Darren Delai Sun
Wastewaters with high concentrations of organic pollutants pose a great challenge for membrane filtration due to their severe fouling propensity. In this study, a hydrogel forward osmosis (FO) membrane is explored for treating wastewaters of high concentration organic pollutants. This FO membrane has an ultrathin hydrogel selective layer, which is highly hydrophilic (water contact angle: as low as 18°) and smooth (surface roughness: <5 nm). Investigated with typical organic foulants (protein, alginate, humic acid, and oil) of high concentration (2000 ~ 20000 mg/L), this hydrogel FO membrane exhibits remarkably superior antifouling capability, with its water flux decline ratio lower than a quarter of commercial FO membrane's under identical experimental conditions...
January 3, 2018: Environmental Science & Technology
Nazikussabah Zaharudin, Armando Asunción Salmeán, Lars Ove Dragsted
Edible seaweeds are valuable because of their organoleptic properties and complex polysaccharide content. A study was conducted to investigate the potential of dried edible seaweed extracts, its potential phenolic compounds and alginates for α-amylase inhibitory effects. The kinetics of inhibition was assessed in comparison with acarbose. The methanol extract of Laminaria digitata and the acetone extract of Undaria pinnatifida showed inhibitory activity against α-amylase, IC50 0.74 ± 0.02 mg/ml and 0...
April 15, 2018: Food Chemistry
Faheem Ullah, Fatima Javed, Mbh Othman, Abbas Khan, Rukhsana Gul, Zulkifli Ahmad, Hazizan Md Akil
Addressing the functional biomaterials as next-generation therapeutics, chitosan and alginic acid were copolymerized in the form of chemically crosslinked interpenetrating networks (IPNs). The native hydrogel was functionalized via carbodiimide (EDC), catalyzed coupling of soft ligand (1,2-Ethylenediamine) and hard ligand (4-aminophenol) to replace -OH groups in alginic acid units for extended hydrogel- interfaces with the aqueous and sparingly soluble drug solutions. The chemical structure, Lower solution critical temperature (LCST ≈ 37...
December 29, 2017: Journal of Biomaterials Science. Polymer Edition
Patrick D Mathews, Ana Carolina Monge Fernandes Patta, Joao Vitor Gonçalves, Gabriella Dos Santos Gama, Irene Teresinha Santos Garcia, Omar Mertins
Biomaterials conceived for vectorization of bioactives are currently considered for biomedical, biological and environmental applications. We have produced a pH sensitive biomaterial composed of natural source alginate and chitosan polysaccharides for application as drug delivery system via oral administration. The composite particles preparation was in situ monitored by means of isothermal titration calorimetry. The strong interaction established between the macromolecules during particles assembling lead to 0...
December 28, 2017: Biomacromolecules
Kefyalew Dagnew Addisu, Balkew Zewge Hailemeskel, Shewaye Lakew Mekuria, Abegaz Tizazu Andrgie, Yu-Chun Lin, Hsieh-Chih Tsai
Manganese-based nanomaterials are an emerging new class of magnetic resonance imaging (MRI) contrast agents (CAs) that provide impressive contrast abilities. MRI CAs that can respond to pathophysiological parameters like pH or redox potential are also highly demanded for MRI guided tumor diagnosis. Until now, synthesizing nanomaterials with good biocompatibility, physio-chemical stability, and good contrast effects remain challenging. This study investigated two new systems of calcium/manganese cations complexed with either alginate-polydopamine or alginate-dopamine nanogels (AlgPDA(Ca/Mn) NG or AlgDA (Ca/Mn) NG)...
December 26, 2017: ACS Applied Materials & Interfaces
Heetak Han, Jung Seung Lee, Hyunchul Kim, Sera Shin, Jaehong Lee, Jongchan Kim, Xu Hou, Seung-Woo Cho, Jungmok Seo, Taeyoon Lee
Herein, a droplet manipulation system with a superamphiphobic (SPO)-superamphiphilic (SPI) patterned polydimethylsiloxane (PDMS) substrate is developed for a multiplex bioassay from single-droplet samples. The SPO substrate is fabricated by sequential spraying of adhesive and fluorinated silica nanoparticles onto a PDMS substrate. It is subsequently subjected to oxygen plasma with a patterned mask to form SPI patterns. The SPO layer exhibits extreme liquid repellency with a high contact angle (>150°) towards low-surface-tension and viscous biofluidic droplets (e...
December 20, 2017: ACS Nano
Anna Sola, Laura Saenz Del Burgo, Jesús Ciriza, Rosa Maria Hernandez, Gorka Orive, Jorge Martin Cordero, Priscila Calle, Jose Luis Pedraz, Georgina Hotter
Epithelial to mesenchymal transition (EMT) has emerged as a key process in the development of renal fibrosis. In fact, EMT-derived fibroblasts contribute to the progression of chronic renal disease. In addition, anti-inflammatory M2 macrophages have exhibited a great influence on renal fibrosis. However, because of the high impact that the inputs of different environmental cytokines have on their phenotype, macrophages can easily lose this property. We aim to known if microencapsulated macrophages on M2-inducing alginate matrices could preserve macrophage phenotype and thus release factors able to act on epithelial cells to prevent the epithelial differentiation towards mesenchymal cells...
November 2018: Drug Delivery
Wenli Qin, Zongli Xie, Derrick Ng, Ying Ye, Xiaosheng Ji, Stephen Gray, Jianhua Zhang
Colloidal silica involved fouling behaviors in direct contact membrane distillation (DCMD), vacuum membrane distillation (VMD) and sweeping gas membrane distillation (SGMD) were studied. Three foulants were used in the experiments, including colloidal silica as representative of particulate foulants, calcium bicarbonate as dissolved inorganic foulant, and NOM (humic acid + alginate + BSA) as the dissolved organic foulant. The three types of fouants were combined to produce four different feed waters: silica alone; silica + calcium bicarbonate; silica + NOM; and silica + calcium bicarbonate + NOM...
December 5, 2017: Water Research
Ceri Austin, Derek Stewart, J William Allwood, Gordon J McDougall
A polyphenol-rich extract (PRE) from the edible seaweed, Ascophyllum nodosum, inhibited pancreatic lipase activity in an oil-based turbidimetric assay with an IC50 of 200 μg gallic acid equivalents (GAE) perassay) [∼230 μg DW] whereas the known inhibitor, Orlistat, gave an IC50 at 0.4 μg per assay. A phlorotannin-enriched fraction (TRF) purified from the PRE was more potent with an IC50 = 60 μg GAE per assay (∼65 μg DW). When the assay was started by the addition of lipase, both Orlistat and TRF were much less effective which suggests that pre-incubation of enzyme and inhibitor improved inhibition...
December 15, 2017: Food & Function
Tingting Zhou, Jiagen Li, Xu Jia, Xubo Zhao, Peng Liu
Novel biocompatible and biodegradable pH/reduction dual-responsive oxidized alginate-doxorubicin (mPEG-OAL-DOX/Cys) prodrug nanohydrogels were designed for tumor-specific intracellular triggered release of anticancer drug DOX, by conjugating DOX via acid-labile Schiff base linkage into the PEGylated oxidized alginate (mPEG-OAL) crosslinked with bioreducible disulfide bond. The effect of the complexation with cyclodextrins (α-CD and -CD) before or after the crosslinking of the mPEG-OAL on the DOX content and controlled release performance was investigated...
December 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Martin Sterner, Mauricio Sodré Ribeiro, Fredrik Gröndahl, Ulrica Edlund
A new approach to process Saccharina latissima algal biomass was developed using sodium citrate and a polyvalent cation-specific resin to sequentially extract the alginate into several usable fractions. The fractionation was performed in a cyclic manner, utilizing a stepwise removal of the native polyvalent ions present in the algae to isolate fractions of alginate with different solubility in the presence of these ions. Sodium citrate was used in different concentrations in the extraction solution to remove polyvalent cations to adjust the alginate liberation while AMBERLITE IRC718 resin was added to further remove these ions and regenerate the extraction solution...
2017: Journal of Applied Phycology
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