Alginate Blend Research Articles

Encapsulation of stevia rebaudiana Bertoni aqueous crude extracts by ionic gelation – Effects of alginate blends and gelling solutions on the polyphenolic profile

We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7–101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions.

Study of phase separation in blends of silk fibroin and sodium alginate in solution and in solid state

Silk fibroin (SF) and sodium alginate (SA) are natural polymers with many applications as biomaterials. It is possible to make blends with them in order to improve their properties. Those blends are partially miscible; therefore, understanding the mechanism and phase equilibrium of this system is important to better understand the interaction between these natural polymers. This work analyzed the mechanism of phase separation of SF and SA blends with different composition in solution and in the solid state (as membranes) using small angle light scattering with a He-Ne laser. Polymer interaction and conformation were investigated by Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and X-Ray Diffraction (XRD), and membrane morphology was analyzed by Scanning Electron Microscopy (SEM). SEM images showed interpenetrated globules in the matrix. Light scattering profile for blends in solution and in the solid state showed a peak of intensity suggesting that phase separation occurs by spinodal decomposition.

Development of sericin/alginate beads of ketoprofen using experimental design: Formulation and in vitro dissolution evaluation

The development of new forms of drugs from the current existing active principles is an alternative to the costly and time-consuming process of developing new ones. The blend of sericin and alginate has been proposed as a polymer matrix for the incorporation of ketoprofen as a modified formulation. An experimental design was performed by varying the initial amount of alginate and drug added. Incorporation efficiency, drug loading, and release time of 85% were applied as response variables. Drug loading was statistically affected by both independent variables and the highest value (40.25 ± 0.23%) was achieved for the lower amount of alginate and higher amount of ketoprofen initially added. The incorporation efficiency was statistically affected only by the amount of alginate and its higher values were reached by the smaller amount of alginate added. Time to release 85% was not affected by any of the independent variables, although the longer times were achieved for the greater amount of drug added. In general, the best particle produced was K3, produced with the lowest amount of alginate and higher amount of ketoprofen initially added. The characterization analyzes of SEM, FTIR, XRD, OM and TGA confirmed the incorporation of ketoprofen.

Enhanced swelling and multiple-responsive properties of gelatin/sodium alginate hydrogels by the addition of carboxymethyl cellulose isolated from pineapple peel

Natural polymers hydrogels were prepared by solution blending of gelatin, sodium alginate and carboxymethyl cellulose isolated from pineapple peel, and cross-linking with CaCl2 and glutaraldehyde solutions. The prepared hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and field emission scanning electron microscope. The swelling behaviors and responsiveness to pH, salt and electric field were also investigated. The swelling dynamic mechanism of hydrogels agreed well with the Fickian diffusion and Schott’s pseudo second order models. The addition of carboxymethyl cellulose enhanced the swelling ability of the hydrogels in the selected mediums and sensitivities to pH, salt and electric field. The electric response of the hydrogels showed pH-dependent, ionic strength-dependent and electric voltage-dependent. This multiple-responsive characteristic of the prepared hydrogels was conducive to application as potential biomaterials such as microsensors, actuators, artificial muscles and drug delivery systems.

Comparison of extrusion and co-extrusion encapsulation techniques to protect Lactobacillus acidophilus LA3 in simulated gastrointestinal fluids

This study aimed to compare two processes for the encapsulation of Lactobacillus acidophilus LA3 using alginate or a blend of alginate–shellac as the wall material and sunflower oil as the core. The particles were dried and stored for up to 60 days at 25 °C for stability studies, and the survival of the encapsulated probiotics in simulated gastrointestinal fluids was evaluated. The viability of the LA3 encapsulated by co-extrusion using alginate or a blend of alginate–shellac was, respectively, 6.2 and 7.2 log CFU/g (colony-forming units per gram), after 60 days of storage, while the viability of the LA3 encapsulated by extrusion was, respectively, 5.3 and 6.2 log CFU/g. The particles produced with the blend of alginate–shellac presented additional protection to the probiotics, as revealed by the increased survival rates in simulated gastrointestinal fluids. Taken together, these data provide a promising alternative for the incorporation of the probiotic L. acidophilus LA3 into new functional foods.

Structure evolution of pullulan–alginate edible films during drying studied by low‐field NMR

AbstractThe evolutions of spatial structure for pullulan, alginate, and pullulan–alginate blend aqueous solutions during drying were investigated by low‐field nuclear magnetic resonance. For pullulan solutions, during the first 1,320 min of drying, NMR signal intensity in profiles did not vary with position. Thereafter, the apparent shift of the air–pullulan interface began at 1,440 min, indicating the onset of progressive shrinkage of pullulan samples. Similar shrinkage phenomena were observed for alginate and pullulan–alginate blend solutions. In contrast, spatial structural heterogeneity was observed for alginate solution during drying time from 1,200 to 1,560 min, due to the formation of a skin layer near the air–alginate interface. Based on the change of polymer solutions during drying, two‐stage evaporation process was detected in the aqueous pullulan, alginate, and their blend solutions. Moreover, the evaporation rate of water during the second stage of drying was significantly lower than that of the first stage.Practical applicationsEdible films have emerged as an alternative to synthetic petroleum‐based polymers for food packaging. The evolutions of spatial structure of pullulan–alginate solutions during drying were studied by monitoring of their NMR profiles. Information shown in this study would provide some scientific basis for studying film‐forming mechanism of edible films and their applications in the food field.

SODIUM ALGINATE–LOCUST BEAN GUM IPN HYDROGEL BEADS FOR THE CONTROLLED DELIVERY OF NIMESULIDE-ANTI-INFLAMMATORY DRUG

Objective: The objective of this study was to formulate and evaluate the drug release studies using locust bean gum (LBG) and sodium alginate (NaAlg) and cross-linked with glutaraldehyde for the controlled release (CR) of nimesulide, an anti-inflammatory drug.Methods: Locust bean gum (LBG) and sodium alginate (NaAlg) blend hydrogel beads were prepared by an extrusion method using glutaraldehyde as a crosslinker. Nimesulide an anti-inflammatory drug was encapsulation within LBG/NaAlg blend hydrogel beads. Morphology, size, encapsulation efficiency and drug release from these hydrogel beads were evaluated by different characterization techniques such as fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), x-ray diffraction (X-RD) studies.Results: Drug-loaded hydrogel beads were analyzed by FTIR, which indicates the interaction between drug and polymers. DSC thermograms on drug-loaded microbeads confirmed the polymorphism of nimesulide and indicated a molecular level dispersion of the drug in the hydrogel beads. SEM confirmed the spherical nature and rough surface of the hydrogel beads produced. X-RD study was performed to understand the crystalline nature of drug after encapsulated into the hydrogel beads and confirmed the complete dispersion of the drug in the polymer matrix. In vitro release studies conducted in pH-7.4 which indicated a dependence of release rate on the amount of drug loading and the amount of LBG/NaAlg, but slow release rates were extended up to 48 h. The cumulative release data were fitted to an empirical equation to compute diffusion exponent (n) which indicated the non-fickian trend for drug release.Conclusion: These results clearly demonstrated that the ability of these newly developed hydrogel beads containing nimesulide for its sustained release could possibly be advantageous to patient compliance with reduced dosing interval.

The role of alginate lyases in the enzymatic saccharification of brown macroalgae, Macrocystis pyrifera and Saccharina latissima

In this work, we have compared the carbohydrate content and the enzymatic saccharification of the brown algae Macrocystis pyrifera from Chile and Saccharina latissima from Norway. M. pyrifera contained 40% mannitol, 31% uronic acids and 15% glucose, while S. latissima contained 37% glucose, 30% uronic acids and 25% mannitol. Thus, the ratio between mannitol and glucose was much higher for M. pyrifera. Acid pre-treated and untreated algae were enzymatically saccharified in two steps; first at pH7.5, 25°C for 12h with a blend of recombinant alginate and oligoalginate lyases, then the pH was changed to 5.2, a commercial cellulase cocktail was added and saccharification continued at 50°C for 4h. These experiments showed that the use of recombinant alginate lyases and oligoalginate lyases in combination with cellulases increased the release of glucose from untreated seaweed. However, for saccharification of pretreated algae, only cellulases were needed to achieve high glucose yields. Finally, it was shown that brown algae hydrolysates could be used as a growth medium to produce microbial ingredients, such as Candida utilis yeast.

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

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.

Fabrication and Application of Polyethylenimine/Ca-Alginate Blended Hydrogel Fibers as High-Capacity Adsorbents for Recovery of Gold from Acidic Solutions

High-capacity polyethylenimine (PEI)/Ca-alginate blended hydrogel fibers were fabricated via three steps, viz. electrostatic blending of PEI and alginate, ionotropic gelation of alginate and CaCl2, and fixing of PEI into the Ca-alginate matrix, using glutaraldehyde (GA) as a crosslinker. Two crosslinking approaches resulted in different stabilities and gold uptake capacities of the prepared sorbents. Post-crosslinking approach was more efficient than pre-crosslinking likely owing to the better crosslinking efficiency, leading to better stability and sorption capacity. Furthermore, X-ray diffraction (XRD) study revealed the reduction of Au (III) to metallic gold, Au (0) in the crosslinked fibers. The Au (0) predominancy was confirmed with a metal desorption study. The present study thus demonstrates the possibility of recovering metallic gold from aqueous solutions by direct adsorption-coupled-reduction approach using GA-crosslinked PEI/Ca-alginate fibers.

A promising wound dressing material with excellent cytocompatibility and proangiogenesis action for wound healing: Strontium loaded Silk fibroin/Sodium alginate (SF/SA) blend films

Effectively stimulating angiogenesis is great challenge in wound care management. It’s necessary to develop a new wound dressing with angiogenic capacity. Therefore, strontium loaded SF/SA blend films were prepared as a potential wound dressing material, and their physicochemical and bioactive properties were evaluated. The strontium loaded SF/SA blend films (especially the strontium loaded SF/SA blend films prepared by treating with 5mg/ml Sir solution) could meet the needs of a wound dressing such as water absorption, water vapor transmission rate, mechanical properties and fibroblasts-cytocompatibility. What’s more, these films had a potential to induce angiogenesis by improving vascular VEGF and bFGF protein secretion, which was important for wound dressings. Based on the previous studies, we could infer this novel wound dressing possesses the antibacterial activity. The present study suggests that the strontium loaded SF/SA blend film prepared by treating with 5mg/ml Sr solution are a promising biomaterial for wound dressing application.

Aqueous Polyurethane Dispersions - Sodium Alginate Based Blends and Hydrogels

The film forming binary polyurethane-alginate blends and based hydrogels, containing different alginate content, were prepared by blending of anionic polyurethane dispersions (APD) and aqueous sodium alginate (SA) solution. Binary blends of APD and SA were cast in film form from mixed aqueous polymer solutions by solvent evaporation. Post-treatment of as-cast films with CaCl2 leaded tot he hydrogels formation. The thermal stability, thermal transition, water-swelling, mechanical properties and gas permeance for O2 and CO2 of two kinds of films were examined according to alginate content. Irrespective of composition, blend samples gave a single glass transition temperature (Tg), indicating the formation of thermodynamically miscible phase. The shift of Tg in hydrogels to the higher temperatures indicated the possible simultaneous occurrence of a chelate complexation of SA with Ca+2 cations, cross-links between polyurethane chains, having carboxylate anions, with Ca2+ cations, and interactions between SA and anionic polyurethane, resulting in the formation of an semi-interpenetrating network structure. The relationships between the films structure, their physicochemical properties and alginate content have been discussed.

Scale-Up Preparation and Characterization of Collagen/Sodium Alginate Blend Films

In an effort to produce scale-up of edible films, collagen-based films including different amounts of sodium alginate (CS) were prepared by casting method. Films were characterized based on their rheological, thermal, and mechanical properties, water vapor permeability (WVP), and oxygen permeability (OP). The microstructures were also evaluated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform-infrared spectroscopy (FTIR). Furthermore, the addition of sodium alginate effectively improved the viscosity and thermal stability, significantly increased TS, and decreased E and WVP (P<0.05), but with no obvious effect on OP (P>0.05). SEM and AFM showed homogeneous matrix, with no signs of phase separation in the blends. Overall, films (CS2) produced using collagen (g) : sodium alginate (g) = 10 : 2 showed suitable rheological property (apparent viscosity was 4.87 m Pa s−1) and better TS (26.49 Mpa), E (64.98%), WVP (1.79 × 10−10 g·cm−1·s−1·Pa−1), and OP (3.77 × 10−5 cm3·m−2·d−1·Pa−1).

Inkjet Bioprinting of 3D Silk Fibroin Cellular Constructs Using Sacrificial Alginate.

Silk fibroin is a natural protein which has shown great promise for tissue engineering but is not printable due to slow gelation or harsh gelation conditions which are not cell-friendly. In this study, a two-step gelation process is proposed for the printing of silk fibroin, which utilizes alginate as a sacrificial hydrogel during an inkjetting-based process. A cell-laden blend of alginate with silk fibroin is utilized to achieve rapid gelation by calcium alginate formation during printing; it is followed by horseradish peroxidase (HRP) catalyzed covalent cross-linking of the fibroin protein at tyrosine residues after printing. This two-step gelation process successfully enables 3D bioprinting of well-defined cell-laden silk fibroin constructs suitable for long-term culture. The constructs remain intact after calcium chelation to liquefy the alginate component, demonstrating the formation of silk fibroin hydrogel. NIH 3T3 fibroblasts proliferate and spread through the hydrogel after printing. Increasing metabolic activity is observed for 5 weeks after printing, and histology shows dense cell populations in cultured constructs. The proposed two-step gelation technique is expected to enable 3D silk fibroin printing for various applications.

Performance evaluation of sodium alginate–Pebax polyion complex membranes for application in direct methanol fuel cells

ABSTRACTA novel polyion complex membrane was synthesized for direct methanol fuel cell application through the blending of the natural biopolymer sodium alginate (SA) with the synthetic polymer Pebax [poly(ether‐block‐amide)]. The blend was covalently crosslinked with glutaraldehyde (GA) and sulfonated with sulfuric acid (H2SO4), after which characterization by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffractometry, thermogravimetric analysis, and universal testing machine techniques was carried out. The SA–Pebax–GA–H2SO4 membrane exhibited a high ion‐exchange capacity of 2.1 mequiv/g, an optimum water sorption of 17.3%, and a low methanol sorption of 9.5%. A desirably low methanol permeability of 9.25 × 10−8 cm2/s and a high proton conductivity of 0.067 S/cm were obtained as against corresponding values of 1.82 × 10−6 cm2/s and 0.077 S/cm reported for a commercial Nafion 117 membrane. Moreover, a high selectivity of 6.5 × 105 Ss/cm3 with a power density of 0.17 W/cm2 was achieved with the indigenous blend membrane at a potential of 0.34 V. Molecular dynamics simulation was performed along with the estimation of fractional free volume to explain the transport behavior of water and methanol molecules through the membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44485.

Sodium Alginate with PEG/PEO Blends as a Floating Drug Delivery Carrier - In vitro Evaluation.

Purpose: Floating drug delivery system reduces the quantity of drug intake and the risk of overloading the organs with excess drug. Methods: In the present study, we prepared the blends of sodium alginate with polyethylene glycol (PEG) and polyethylene oxide (PEO) as a matrix, sodium hydrogen carbonate as a pore forming agent, methyl cellulose as a binder and barium chloride containing 10% acetic acid as a hardening agent. Different ratios of pore forming agent to the polymer blend was used to prepare the floating beads with different porosity and morphology. Ciprofloxacin hydrochloride was used as a model drug for the release kinetics studies. Results: The beads were characterized by optical and FESEM microscopy to study the morphology and pore dimensions. The results obtained shows decrease in beads size with increase in the concentration of the pore forming agent. The swelling properties of the beads were found to be in the range of 80% to 125%. The release kinetics of the ciprofloxacin from the beads was measured by UV-Visible spectroscopy at λmax of 278nm and the results shows for highly porous beads. Conclusion: By varying the amount of alginate and pore forming agent the release kinetics is found to get altered. As a result, ciprofloxacin hydrochloride release is found to be sustained from the blended beads.

Evaluation of Extracted Chitosan from Portunus Pelagicus for the Preparation of Chitosan Alginate Blend Scaffolds

In recent years there is a growing need in generating a biocompatible and cost effective porous scaffold for tissue engineering purposes. Therefore, this study focused on conversion of the shell waste of locally available crab variety P.pelagicus (Blue swimming crab) into the chitosan scaffold. As the poor mechanical strength of chitosan limits its usage in tissue engineering, it was blended with alginate. The scaffolds were prepared by the freeze gelation method which requires less time and minimum energy, with fewer residual solvent and easier to scale up. To the best of our knowledge there are no reports on scaffold preparation from the extracted chitosan, blended with alginate by freeze gelation method. The biological properties of chitosan-alginate scaffolds (Cts–Alg) were evaluated and compared with those of chitosan scaffolds. The prepared scaffolds were characterized by SEM, swelling property, in vitro enzymatic degradation, and hemo, biocompatibility properties. Chitosan-alginate scaffolds had an average pore size of 40 μm and tensile strength of 0.564 ± 0.0.018 % MPa. Its swelling ratio was 27.5 ± 0.28 %, with mass loss percentage of 10 ± 0.33 % after 4 weeks of degradation. It has exhibited good hemocompatible properties too. Mouse fibroblast 3T3 cells were able to adhere and proliferate well in the blended scaffold. All these results indicated that chitosan-alginate scaffold is a suitable alternative substitute for tissue engineering.

Effects of Crosslink Agents on Sodium Alginate and Lignosulphonic Acid Blends

Blends of sodium alginate (SA) and lignosulphonic acid (LS) has been prepared in the ratio of 80/20. The prepared blends were crosslinked using chlorides of calcium, barium, strontium and aluminum. The crosslinking of blends was done for different time intervals and then these blends were subjected for swelling studies in aqueous medium of pH 7.4. The observations indicate that the crosslinking is diffusion controlled and is affected by the size of metal ion and the type of alginate used. The improved swelling time for crosslinked blends in aqueous medium supports the fact that the stability under physiological conditions of the blends is improved due to crosslinking with the metal ions. Calcium chloride and barium chloride forms strong crosslink with the blend. Calcium ion crosslinked blends can be considered suitable for biomedical drug applications. The investigations on crosslinked blends using FTIR, SEM, XRD and EDAX are in close agreement with swelling results.

Multichannel 3D plotting for complex tissue equivalents and implants for defects at tissue interfaces

Event Abstract Back to Event Multichannel 3D plotting for complex tissue equivalents and implants for defects at tissue interfaces Michael Gelinsky1, Ashwini R. Akkineni1, Kathleen Schütz1, Tilman Ahlfeld1, Yvonne Förster1, Falko Doberenz1, Maja Brückner1 and Anja Lode1 1 TU Dresden, Centre for Translational Bone, Joint and Soft Tissue Research, Germany Introduction: Additive Manufacturing (AM) opens up fascinating possibilities for the generation of implants and tissue engineering (TE) constructs. 3D plotting, i. e. extrusion of pasty biomaterials at room or physiological temperature, allows utilization of a great variety of materials and incorporation of sensitive substances like drugs, growth factors or even living cells. Multichannel-3D plotting enables processing of more than one material within one construct and therefore manufacturing of complex specimens, e.g. for application at tissue interfaces and/or generation of improved tissue equivalents which closer mimic natural tissues than conventional TE strategies. We wanted to investigate whether we can load calcium phosphate cement (CPC) pastes with growth factors and combine them with biopolymer hydrogels for AM of complex scaffolds. Further questions were whether live cells can be included within the hydrogels and both materials combined in joint strands with core/shell morphology. Materials and Methods: For 3D plotting BioScaffolder 2.1 from GeSiM (Grosserkmannsdorf, Germany) was used. As CPC paste an hydroxyapatite (HA) forming α-tricalcium phosphate-based precursor mixture, suspended in a biocompatible oily phase[1], was utilized. Blends of alginate (3%) and methylcellulose (9%)[2] were used as hydrogel material. Before scaffold preparation, all materials were sterilized. After plotting of the scaffolds in air they were stabilized by immersion in 100 mM CaCl2 solution. As growth factor, VEGF (vascular endothelial GF) was used and human mesenchymal stroma cells (hMSC) for embedding experiments. For preparation of core/shell strands self-made double-nozzle extruders were applied, mounted onto the 3D plotter. The scaffolds were fully characterized including morphology, mechanical properties, VEGF release (ELISA and bioassay), cell survival (live/dead and MTT staining) and osteogenic differentiation. One type of scaffold was tested in a pilot animal study in a 5 mm femur defect in rat, stabilized with a metal plate. Results and Discussion: Combination of CPC and biopolymer hydrogel strands within one scaffold was possible. Immersion of the scaffolds after plotting in calcium ion containing media led to CPC setting and simultaneously to alginate crosslinking. Methylcellulose which improved viscosity and therefore plottability of the hydrogel paste slowly dissolves during further storage in aqueous media, creating an additional microporosity (besides the macropores = space between the strands). We could demonstrate that VEGF could be successfully incorporated in CPC as well as hydrogel strands; for mixing with CPC binding of the GF to chitosan microparticles was advantageous. GF release was much faster from hydrogel compared to CPC – and retained biological activity of released VEGF was proven with an bioassay using endothelial cells. Human MSC could be mixed into the biopolymer hydrogel blend and survived extrusion, scaffold crosslinking and additional 3 weeks of culture. Osteogenic differentiation could be induced by applying common supplements. In addition, the animal pilot study proved biocompatibility of the new type of scaffold and biological activity of the released VEGF in vivo. A novel type of core/shell strands with a stiff shell (CPC) and soft core (hydrogel) and 3D scaffolds made thereof could be manufactured using double-nozzle extruders. Such material combinations within one extruded strand open up new possibilities for dual drug loading and release. Conclusion: Multichannel 3D plotting is a versatile AM technology and allows combination of such different biomaterials like a calcium phosphate cement and a biopolymer hydrogel. Due to the mild processing conditions sensitive components like GF and living cells can be incorporated. Of special interest is the combination of different biomaterials in strands with core/shell morphology. This technology can be further developed towards more complex tissue and organ models. Saxon State Ministry for Higher Education, Research and the Arts (SMWK) for funding

Development of pH sensitive polyurethane–alginate nanoparticles for safe and efficient oral insulin delivery in animal models

Blends of sodium alginate (ALG) and polyurethane (PU) synthesized from depolymerised polyethylene terephthalate (PET) to formulate insulin loaded PU–ALG nanoparticles for the purpose of controlled oral insulin delivery.