Synthetic Alginate Research Articles

Proficiency of some synthetic alginate derivatives for sequestration of Iodine-131 from radioactive liquid waste

ABSTRACT The current effort in environmental remediation is aimed at removing iodine-131 radionuclide from radioactive liquid waste produced by an Egyptian nuclear power plant using some synthesised alginate derivatives. Two different copolymers, namely sodium alginate poly (acrylic acid) (P1) and sodium alginate poly (acrylic acid-methacrylic acid) (P2), are prepared using gamma radiation. The ability of these polymers to remove 131I radionuclide as sorbents has been investigated. The synthesised polymers exhibit excellent adsorption performance for 131I ions, and the adsorption equilibrium requires only 30 min, which reveals that the sorption process is kinetically faster than most of the other materials reported previously. The removal percents for 131I radionuclide at a pH of 3.0 at room temperature on P1 and P2 are 77.7% and 84.2%, respectively. The sorption capacities of the two polymers demonstrate that P2 > P1, with capacities of 67.9 and 58.5 mg/g, respectively. Four linear kinetic models are investigated: pseudo-first order, pseudo-second order, Elovich, and Weber–Morris models. Regarding their calculated parameters, these models indicate that the adsorption process of I-ions on both P1 and P2 is controlled by chemisorption. Four equilibrium isotherm models (Redlich-Peterson, Langmuir, Freundlich, and Harkin-Jura) are investigated, revealing that the adsorption process is a monolayer and multilayer process on a heterogeneous surface.

Proficiency of Some Synthetic Alginate Derivatives for Sequestration of Iodine-131 from Radioactive Liquid Waste

Proficiency of Some Synthetic Alginate Derivatives for Sequestration of Iodine-131 from Radioactive Liquid Waste

Evaluation of Demineralized Bone Matrix Particles Delivered by Alginate Hydrogel for a Bone Graft Substitute: An Animal Experimental Study.

BackgroundOur objective was to explore a synthetic alginate hydrogel delivery system for the delivery of demineralized bone matrix (DBM) particles for bone graft substitutes.Material/MethodsThe physiochemical properties of surface morphology, porosity measurements, in vitro degradation, equilibrium swelling, and mechanical testing of combined DBM powder and alginate in amounts of 0 mg/1 mL, 25 mg/1 mL, 50 mg/1 mL, and 100 mg/1 mL were detected. In vitro cell culture and in vivo studies using Sprague-Dawley rats were performed to evaluate the biocompatibility and osteoinductivity of DBM-alginate (ADBM) composites.ResultsDBM particles were uniformly scattered in all composites, and macro-scale pores were omnipresent. All composites showed a similar low degradation rate, with approximately 85% of weight remaining after 15 days. As the concentration of DBM particles in composites increased, degradation in collagenase and elastic modulus increased and the pore area and swelling ratio significantly decreased. No cytotoxicity of ADBM or alginate on mesenchymal stem cells (MSCs) was observed. Cell cultivation with ADBM showed greater osteogenic potential, evidenced by the upregulation of alkaline phosphatase and alizarin red staining activity and the mRNA expression level of marker genes RUNX2, OCN, OPN, and collagen I compared with the cells grown in alginate. Evaluation of ectopic bone formation revealed the osteoinductivity of the ADBM composites was significantly greater than that of DBM particles. Osteoinduction of the composites was demonstrated by a cranial defect model study.ConclusionsThe delivery of DBM particles using a synthetic alginate hydrogel carrier may be a promising approach in bone tissue engineering for bone defects.

The effect of synthetic alginate sulfate hydrogels with recombinant PDGF-BB on Wound healing.

Platelet-derived growth factor (PDGF-BB) is an important factor in the regeneration and wound healing. One of the problems is that there is not enough efficiency in the transmission or delivery of such factors in the wound site. In this study, alginate sulfate hydrogel was synthesized with recombinant PDGF-BB growth factor for achieving a quick method in wound healing. In this study, Alginate sulfate hydrogel was made by photo-crosslinking method and methacrylate. Its toxicity was evaluated by MTT assay. Transforming growth factor was studied in releasing from synthesized alginate sulfate hydrogels and also, lack of toxicity was confirmed, and hydrogel was made with a recombinant human growth factor. Wounds were created with a diameter of 10 mm on the back of rats in order to check the wound healing. This study showed that alginate sulfate hydrogels-PDGF-BB were faster in wound healing than non-sulfate alginate hydrogels-PDGF-BB. Therefore, the controlled delivery of growth factor system can be a powerful idea for therapeutic applications for wound healing. Alginate sulfate hydrogel with recombinant growth factor 4 µg/cm2 (PDGF-BB) was very suitable for wound healing (Tab. 1, Fig. 3, Ref. 34).

Influence of K+ and Na+ ions on the degradation of wet‐spun alginate fibers for tissue engineering

ABSTRACTA synthetic type of wet‐spun alginate fibers were immersed in simulated body fluid(SBF) composed of K+, Na+, and Ca2+ cations with various concentrations. Experimental measurements revealed that Na+ had a greater impact on degradability than that of K+ ion. The finding was further confirmed by the characterization of mass loss, ICP, XRD, and theoretical analyses. The degradation process and mechanism were demonstrated through the research on swelling behavior and mass loss. Besides, the wet‐spun alginate fibers were characterized by FT‐IR, XRD, and SEM. The results showed that the degradation mechanism could be attributed to the ion‐exchange between Ca2+ of the synthetic alginate fibers and Na+, K+ of the solutions under the osmotic pressure. The synthetic fibers were swelled and then degraded faster with the presence of Na+ ion presented greater influence on degradability compared with K+ ion. The degradation results of a mechanical rupture of fibers due to excessive water uptake without the occurrence of any chemical changes in the spun alginates structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44396.

Healing Effects of Synthetic and Commercial Alginate Hydrogel Dressings on Wounds: A Comparative Study

Background: Hydrogels based on natural ingredients, such as alginate, are considered promising wound dressings. Alginic acid, a polysaccharide polymer, is a structural component of the cell walls of brown algae. The important features of alginates used in biological dressings include non-toxicity, biocompatibility, biodegradability, hydrophilicity, and excellent swelling behavior. Objectives: In this study, the effects of alginate hydrogels and commercial alginate dressings were studied with regard to wound recovery in a rat model. Methods: Fifteen Wistar rats were divided into three groups of five. One wound measuring 1 × 1 cm square was made on each rat using a template. One rat in each group was euthanized on the 4th, 7th, 14th, and 21st days, and skin samples were taken for histopathological analysis. Results: The findings showed that the average total time of wound healing in the synthetic alginate dressing group was similar to that of the commercial dressing group. In this study, we found that synthetic alginate hydrogels were much more convenient for wound dressings and for the treatment of surface wounds. Conclusions: The treatment outcomes showed that our synthetic alginate hydrogel dressing was highly promising as an alternative wound-healing system, opening a new path toward future research and development.

New insights into organic gel fouling of reverse osmosis desalination membranes

RO membrane fouling is unavoidable as no pretreatment method exists for perfect removal of foulants, which comprise various organic compounds including those from bio-activity. Improved understanding of fouling layer characteristics and correlations of permeation resistance with desalination process parameters (pursued herein) are essential for improving RO-membrane operations. Organic-gel formation is a major type of RO-membrane fouling, in the absence or presence of micro-organisms. Alginates, in dilute brackish-water solutions, are employed as representative gel-forming foulants. Recent experimental results are summarized regarding fouling-layer rheological properties and specific resistance α, focusing on ionic environment and permeation flux effects. Comparative assessment of these characteristics sheds light into the development and structure of gel layers during desalination; in particular, the nature of these layers (i.e. thixotropic material with yield stress) explains their coherence and resistance to shear forces. The investigated relatively thin fouling layers (of practical significance) appear to develop uniformly, with resistance α strongly dependent on flux. Exploiting the rich literature on synthetic alginate hydrogels, a new modeling approach is presented for the resistance α, using measured fouling-gel structural parameters. The fair agreement of predictions with measurements, using no arbitrary constants, warrants further work on model development. Research priorities on membrane fouling are indicated.

Synthetic Alginate is a Carrier of OP-1 for Bone Induction

Bone morphogenetic proteins (BMPs) can induce bone formation in vivo when combined with appropriate carriers. Several materials, including animal collagens and synthetic polymers, have been evaluated as carriers for BMPs. We examined alginate, an approved biomaterial for human use, as a carrier for BMP-7. In a mouse model of ectopic bone formation, the following four carriers for recombinant human OP-1 (BMP-7) were tested: alginate crosslinked by divalent cations (DC alginate), alginate crosslinked by covalent bonds (CB alginate), Type I atelocollagen, and poly-D,L-lactic acid-polyethyleneglycol block copolymer (PLA-PEG). Discs of carrier materials (5-mm diameter) containing OP-1 (3-30 microg) were implanted beneath the fascia of the back muscles in six mice per group. These discs were recovered 3 weeks after implantation and subjected to radiographic and histologic studies. Ectopic bone formation occurred in a dose-dependent manner after the implantation of DC alginate, atelocollagen, and PLA-PEG, but occurred only at the highest dose implanted with CB alginate. Bone formation with DC alginate/OP-1 composites was equivalent to that with atelocollagen/OP-1 composites. Our data suggest DC alginate, a material free of animal products that is already approved by the FDA and other authorities, is a safe and potent carrier for OP-1. This carrier may also be applicable to various other situations in the orthopaedic field.