Incorporation Of Alginate Research Articles

Alginate-HEMA Hydrogels as Promising Biomaterials for Bone Regeneration: InVitro and InVivo Studies.

In the present work, the osteogenic and angiogenic properties of, previously developed, semi-interpenetrated HEMA-EGDMA polymeric networks (sIPN) with and without alginate with application in bone tissue engineering (BTE) were studied. Invitro characterization studies were performed using rat bone marrow progenitor cells (BMPCs), EA.hy926 endothelial cells, and rat vascular smooth muscle cells (VSMCs). Based on the invitro results of both this work and previous ones, the hydrogels were selected to carry out invivo studies to find out their capacity as a biomaterial using a bone regeneration model. Our results indicate that the incorporation of alginate into the HEMA-EGDMA polymeric network promotes osteogenic and angiogenic capacity in cell cultures of BMPCs and both EA.hy926 and VSMCs, respectively, and also increases bone formation and vascular structures in invivo studies, demonstrating its potential use as a biomaterial in BTE.

Characterization and in vitro bioaccessability of optimized chia oil-Capsul-sodium alginate microparticles obtained by 3 nozzle spray-drying

The influence sodium alginate (SA) as an outer layer agent on bioaccessibility and matrix food release of purified chia oil (PCO) microencapsulated was investigated. PCO microparticles with Capsul were elaborated and optimized by response surface methodology (RSM), and then as an encapsulating agent and SA as an outer layer (PCO-Capsul/SA) were designed by mini spray-drying with 2 fluid nozzle (2-N) and 3 fluid nozzle (3-N). The optimal conditions obtained for PCO-Capsul system were: dryer inlet temperature of 114 °C and PCO:Capsul relation of 1:5.42. After the addition of SA out layer, PCO-Capsul/SA microparticles were subjected to in vitro static gastrointestinal digestion. PCO-Capsul/SA occurred mainly in the intestinal phase, showing the suitability of SA as an intestine-site release polymer. However, when PCO-Capsul/SA was incorporated into a yoghurt (Y), microparticles showed a significantly lower PCO matrix food release and bioaccessibility after in vitro digestion than PCO-Capsul-Y microparticles, due to their interaction between SA and Y. SA spray-dried by 3-N showed great potential for vehiculation of omega-3 rich oils in the future incorporation and develop of functional foods. Tweetable abstractThis research shows the role of the sodium alginate incorporation by 3 nozzle spray dryer when the design of an intestine-delivery food ingredient is intended.

ChocOmega-3: Innovative manufacturing of ω-3 enriched chocolate

Three-dimensional (3D) printing technology allows foods to be shaped into unique and complex. Chocolate is frequently used in food printing due to its extrusion melting capacity and attractiveness. In this study, chocolates enriched with ω-3 were produced with 3D printing technology. Using electrospraying, ω-3 was encapsulated within sodium alginate (SA) microparticles, and 3D printed chocolates were coated with those microparticles. Then, the ω-3 blend and ω-3-SA coated chocolates were compared. Before printing, the rheological properties of chocolate were analysed. In addition to their characteristics, the printed chocolates were evaluated for total phenolic content (TPC) and antioxidant capacity, in vitro gastrointestinal digestion, and ω-3 release profile. Fourier transform infrared (FTIR) spectroscopy indicated that ω-3 was successfully incorporated into the SA particles. According to the mechanical testing, the chocolate structures coated with ω-3-SA exhibited higher compressive strength than structures mixed with ω-3. The results revealed that the incorporation of alginate into pure chocolate scaffolds through the coating process resulted in an increase in compressive strength. The TPC and antioxidant capacities of ω-3-SA microparticles (NP) coated and ω-3 mixed chocolate samples were also significantly increased compared to those of pure chocolate after in vitro digestion. ω-3-SA NP-coated chocolate appeared to have a lower quality release profile. The faster release of encapsulated ω-3 at a pH value of 7 may be attributed to the fact that sodium alginate particles dissolve faster in high pH environments. This study revealed that 3D printing technology could be actively leveraged to create food-based products with the necessary ingredients to meet consumer demand.

Self‐assembly and cross‐linking preparation of tilapia‐skin‐derived collagen/alginate hydrogels for efficient wound repairing

AbstractCollagen (Col)‐based composite hydrogels have attracted wide attention because of the additional properties that the second component brings to the hydrogel. Here we reported self‐assembly of collagen and cross‐linking of alginate with Ca2+ to prepare a novel composite hydrogel with Tilapia‐skin‐derived collagen and alginate for efficient wound repairing as the wound dressing. The composite hydrogels exhibited higher water content, coupled with a significant increase in water retention rates upon the incorporation of alginate. As the concentration of alginate rose, the cross‐linking network became tighter, thereby not only modifying the internal structure of the hydrogel but also enhancing its mechanical strength. Moreover, the collagen degradation rate in the composite hydrogels was greatly reduced through addition of alginate, and the collagen‐alginate composite hydrogels exhibited low cytotoxicity, and improved wound healing efficacy, accelerating the maturation of skin attachments and the secretion of vascular endothelial growth factor (VEGF). These results suggested that the composite hydrogel formed by fish‐derived collagen and alginate held promising potential as a wound dressing for challenging and refractory wounds.

A simple method for the simultaneous encapsulation of ciprofloxacin into PEGDA/alginate hydrogels using gamma irradiation

Herein, we present a simple simultaneous method for the fabrication of poly(ethylene glycol) diacrylate/alginate (PEGDA/ALG) hydrogels as three-dimensional (3D) scaffolds for ciprofloxacin (CIP) encapsulation using gamma-irradiation at an irradiation dose of 15 kGy. The absorption capacity of the hydrogels studies demonstrated that the PEGDA/ALG hydrogels showed a small absorption capacity at an acidic pH (pH = 2) and a high absorption capacity at a basic pH (pH = 10). The morphology and functional groups of the PEGDA/ALG hydrogels were successfully determined using scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR), respectively. SEM images observed a decrease in the pore size of the hydrogels with increasing alginate concentration, indicating successful alginate incorporation. FT-IR spectra of the hydrogels indicated that the PEGDA and alginate were crosslinked. The antimicrobial experiment showed that all the PEGDA/ALG hydrogels possessed good antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). These results demonstrate the practicality and efficacy of gamma-irradiation as a one-step method for the simultaneous fabrication of PEGDA/ALG hydrogels and encapsulation of CIP without compromising the bioactivity of the encapsulated CIP.

Application of sodium alginate solution for short-term storage of different volumes of sex-reversed rainbow trout (Oncorhynchus mykiss) testicular sperm

The effect of 0.8% sodium alginate (alginate) addition to Morisawa solution (MS) at pH 8.5 containing 100 mM NaCl, 40 mM KCl, 3 mM CaCl2, 1.5 mM MgCl2 and 50 mM Tris supplemented with an antibiotic (10,000 units penicillin and 10 mg streptomycin per mL in 0.9%) on sex-reversed rainbow trout (Oncorhynchus mykiss) short-term sperm storage for 12 days under anaerobic conditions (4 °C) was tested. Sex-reversed rainbow trout sperm, i.e., testicular sperm (TS), was diluted tenfold in MS + alginate (1:9; TS:MS + alginate) and short-term stored in different containers: an microtube (Mt) with 500 μl capacity, a glass container (Gc) with a 25 ml capacity and a plastic container (Pc) with a 120 ml capacity. In each storage container, TS was short-term stored in sperm columns at two different heights, 0.5 cm (sperm storage volume: 180 μl, 4 ml and 9 ml for Mt., Gc and Pc, respectively) and 1.0 cm (sperm storage volume: 200 μl, 8 ml and 18 ml for Mt., Gc and Pc, respectively). As a control, TS diluted in MS without alginate addition was applied, and sperm were stored for a short time under the same conditions, i.e., storage time, dilution ratio, containers and sperm column height. During the experiment, sperm motility (MOT, %) and sperm curvilinear velocity (VCL, μm s−1) were analyzed at 0, 4, 8 and 12 days during TS short-term storage. It was found that the efficiency of short-term storage of sex-reversed rainbow trout TS was determined both by the sperm column height used (stored sperm volume) and by the addition of MS supplements limiting sperm sedimentation during storage, i.e., 0.8% sodium alginate. Over 12 days, the best storage effects (based on CASA parameters) were obtained when TS was short-term stored in Pc using a 9 ml sperm volume, regardless of alginate addition to MS. In contrast, in Mt. (180 and 200 μl sperm storage volume), TS lost its ability to move more quickly, i.e., on the 4th day, mainly in short-term trials without the addition of alginate. The results also indicate that incorporation of alginate into MS significantly reduces TS sedimentation and enhances fertilization capacity during short-term storage over 12 days, especially at a 1.0 cm sperm column height, i.e., using 200 μl, 8 ml and 18 ml sperm volumes for short-term storage in Mt., Gc and Pc, respectively.

Impact of sodium alginate on binary whey/pea protein-stabilised emulsions

This study aims to understand impact of sodium alginate addition on binary whey/pea protein-stabilised emulsions at various pH. The properties and stability of binary whey/pea protein-stabilised emulsions were characterised by microstructural analysis, droplet size, creaming index in comparison to sole proteins. Protein composition at oil/water interface was examined via SDS-PAGE. Alginate incorporation reduced the droplet sizes and enhanced the emulsion stability at pH 6.6. At pH 11.0, protein only-stabilised emulsion was stable for 21 days, while alginate addition resulted in phase separation in the binary whey/pea protein-stabilised emulsions. The presence of alginate promoted protein adsorption at all pH with both proteins present at the interface. Whey protein displaced pea protein in the binary whey/pea protein-stabilised emulsions over time, whereas alginate addition prevented pea protein from being replaced by whey protein during storage, enhancing their stability. Binary whey/pea proteins with sodium alginate are promising emulsifiers with potential application for liquid creamers.

Development of thick paste-like inks based on superconcentrated gelatin/alginate for 3D printing of scaffolds with shape fidelity and stability

Shape fidelity and integrity are serious challenges in the 3D printing of hydrogel precursors, as they can influence the overall performance of 3D scaffolds. This work reports the development of superconcentrated inks based on sodium alginate and fish gelatin as an appealing strategy to satisfy such challenges and dictate the quality of the printed scaffolds, without using crosslinking strategies during 3D printing. SEM micrographs and micro-CT images indicate the homogeneous distribution of the polysaccharide in the gelatin-based matrix, suggesting its potential to act as a reinforcing additive. The high concentration of gelatin aqueous solution (50 wt%) and substantial incorporation of alginate have facilitated the highly accurate printability and influence the in vitro stability and mechanical properties of the printed scaffolds. An improvement of the stiffness is dictated by the increase of alginate concentration from 20 wt% to 25 wt%, and an increase of Young modulus with about 46% is reached, confirming the reinforcing effect of polysaccharide. This study highlights the potential of paste-type inks to provide high resolution 3D printed structures with appealing structural and dimensional stability, in vitro degradability and mechanical properties for biomedical applications.

Effect of gum arabic or sodium alginate incorporation on the physicochemical and curcumin retention properties of liposomes

Natural biopolymers such as food gums can be effective in improving the physical stability of colloidal particle dispersions. To improve the loading stability of curcumin in liposomes, liposomes with gum arabic (GA) or sodium alginate (SA) (0–2% w/v) were prepared and their physicochemical properties evaluated. Results showed that GA, which has a high surface activity, interacted more with the liposome surface resulting in smaller liposome size and polydispersity. However GA disrupted the internal lamellar structure of the liposomes at low concentrations, resulting in increased flocculation and was associated with poor retention of encapsulated curcumin. In contrast, SA formed a viscious continuous phase due to the gum network which reduced particle mobility and sedimentation, and increased curcumin retention, although this was associated with an increase in particle size and polydispersity index.

Development of hydroxypropyl methylcellulose/sodium alginate blend active film incorporated with Dracocephalum moldavica L. essential oil for food preservation

The present study aimed to fabrication and characterization the hydroxypropyl methylcellulose (HPMC) films containing different concentrations of sodium alginate (0.5, 1, and 3% v/v) and Dracocephalum moldavica L. essential oil (DEO; 1, 3 and 5% v/v) as a biodegradable active packaging system. FTIR analysis confirmed the interaction of alginate groups with the hydroxyl group of HPMC. SEM images indicated that the addition of alginate decreased the size and number of the cracks. As a result, the incorporation of alginate and DEO significantly (p < 0.05) improved the water barrier properties of films and the lowest values of water vapor permeability (.38 × 10-10 g/m.h.Pa), moisture content (6.30 ± 0.08%) and water solubility (29.49 ± 0.04%) were related to the sample containing 1.5% alginate and 5% DEO. Additionally, blending with alginate significantly (p < 0.05) improved the mechanical properties of the films and the blended film sample with 0.5% alginate showed the highest tensile strength (16.13 MPa). The blend films showed high thickness and whiteness Index. Also, the antioxidant activity of the films was enhanced by incorporation DEO and the highest DPPH scavenging activity (74.58 ± 2.31%) was attributed to the samples incorporated with 5% DEO. In conclusion, the fabricated blend film showed considerable potential for active food packaging.

Incorporation of alginate-hyaluronic acid microbeads in injectable calcium phosphate cement for improved bone regeneration

The present study addresses the effect of incorporation of alginate (ALG)-hyaluronic acid (HA) microbeads into calcium phosphate cement (CPC) based injectable bone substitute system. The morphology, chemical structure, setting time, compressive strength, injectability, washout resistance and in-vivo biological performance of CPC and CPC/ALG-HA were examined. Addition of ALG-HA microbeads in CPC resulted in an increase in the injectability and washout resistance of CPC. In-vivo studies of CPC/ALG-HA showed an improved bone formation after 8 weeks compared to CPC. The percent bone healing efficiency of CPC/ALG-HA and CPC was 26.6 ± 0.6 and 21.4 ± 0.5, respectively. The results suggest that CPC/ALG-HA could be used as a potential injectable bone substitute for improved bone regeneration.

Mussel-Inspired Naturally Derived Double-Network Hydrogels and Their Application in 3D Printing: From Soft, Injectable Bioadhesives to Mechanically Strong Hydrogels.

As promising candidates for tissue engineering, hydrogels possess great potential, especially in bioadhesives and load-bearing tissue scaffolds. However, a strategy for synthesizing hydrogels that could achieve the above requirements remains a challenge. Here, a mussel-inspired naturally derived double-network (DN) hydrogel composed of a special combination of two well-characterized natural polymers, hyaluronic acid and alginate, is presented. The key features are its two-step synthesis strategy, which generates injectable and adhesive properties in the first step and then transforms into a DN hydrogel with high mechanical strength and good resilient properties. Based on this strategy, the DN hydrogel could be tamed into a self-supporting three-dimensional (3D) printable bioink. As a rheological modifier, alginate was used to lubricate the covalent cross-linking hydrogels for better extrusion performance. The incorporation of alginate also enhanced the mechanical performance of the soft covalent network by forming reversible alginate-Ca2+ ionic cross-links, which interpenetrate through the outer water-retention scaffold with delicate weblike structures. In vitro cell culture data indicated that our bioink formulation and printing strategy are compatible with human umbilical vein endothelial cells (HUVECs).

Study on the effect of lithium nitrate in ionic conduction properties based alginate biopolymer electrolytes

In this present work, the conduction properties of biopolymer electrolytes (BEs) based alginate incorporation with LiNO3 was studied. FTIR analysis showed there is complexation occurred when incorporation with LiNO3 via COO− group of alginate. The interaction between alginate and LiNO3 shown an improvement in ionic conductivity of BEs where was increased from 3.24 × 10–7 S cm−1 for un-doped sample and achieved optimum value at 1.14 × 10–4 S cm−1 for sample containing with 15 wt. % LiNO3. The prepared samples shown that it has thermally assisted when the temperature is increased and shown Arrhenius behavior. Deconvolution approached revealed that the present ionic conduction of BEs influenced by ionic mobility and diffusion coefficient.

Nanocellulose-Based Inks-Effect of Alginate Content on the Water Absorption of 3D Printed Constructs.

2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO) oxidized cellulose nanofibrils (CNF) were used as ink for three-dimensional (3D) printing of porous structures with potential as wound dressings. Alginate (10, 20, 30 and 40 wt%) was incorporated into the formulation to facilitate the ionic cross-linking with calcium chloride (CaCl2). The effect of two different concentrations of CaCl2 (50 and 100 mM) was studied. The 3D printed hydrogels were freeze-dried to produce aerogels which were tested for water absorption. Scanning Electronic Microscopy (SEM) pictures demonstrated that the higher the concentration of the cross-linker the higher the definition of the printed tracks. CNF-based aerogels showed a remarkable water absorption capability. Although the incorporation of alginate and the cross-linking with CaCl2 led to shrinkage of the 3D printed constructs, the approach yielded suitable porous structures for water and moisture absorption. It is concluded that the 3D printed biocomposite structures developed in this study have characteristics that are promising for wound dressings devices.

Influence of formulation parameters on encapsulation and release characteristics of curcumin loaded in chitosan-based drug delivery carriers

Drugs derived from plants with excellent chemotherapeutic effectiveness and relatively low toxicity may fail to scale through the phyto-drug discovery channel due to lack of appropriate drug delivery systems. These phytoceuticals need compatible carriers that will improve their stability, bioavailability and enhance their effectiveness. In this study, chitosan-based drug delivery carriers (DDCs) containing curcumin as phyto-drug model were prepared either via ionotropic gelation with tripolyphosphate or polyelectrolyte complexation with alginate. Influence of formulation parameters was evaluated using encapsulation and release characteristics as response indices. Crosslinking time, pH of chitosan solution and concentration of curcumin, alginate or tripolyphosphate significantly influenced the encapsulation efficiency, rate of curcumin release and mean release time (MRT) in simulated gastric fluid (SGF). Roughly spherical chitosan-based micro-beads with copious pores within the matrix and of improved encapsulation efficiency (82–93%) were prepared using optimized set of formulation parameters. Incorporation of alginate into the chitosan DDC reduced erosion of curcumin by 30% and extended MRT by 180 min in SGF without net delineating change in release profiles of curcumin in simulated physiological saline and intestinal fluids. Time-dependent in vitro study showed that radical scavenging activity ratio of curcumin was enhanced via encapsulation in chitosan-based DDCs.

Influence of crosslinked alginate on drug release from highly concentrated emulsions

Biocompatible water-in-oil (W/O) and oil-in-water (W/O) highly concentrated emulsions (HIPREs) have been formed at 25°C, in systems consisting of aqueous component/castor oil derivative surfactant/oil compound. In both kinds of emulsions the concentration of internal phase was 83% and the aqueous component consisted of water, 1% sodium alginate solution or a mixture of sodium alginate solution and calcium chloride solution (crosslinked calcium alginate). Ketoprofen (KP) or clindamycine hydrochloride (CH) were solubilized in both kinds of HIPREs and the influence of the composition of the aqueous phase on drug release was studied. Droplet sizes of the W/O HIPREs formed were in the nanometric range, being smaller than other HIPREs described in the literature. Dynamic viscoelastic measurements showed an increase in the elastic modulus (G’) of the emulsions in the presence of alginate or crosslinked alginate. The influence of the order of incorporation of alginate and calcium chloride on the viscosity was demonstrated, as an indication of crosslinking efficiency. KP release to a PBS receptor solution was slower when crosslinked alginate was formed in the internal phase of W/O HIPREs. In contrast, the influence of crosslinked alginate on the release of CH was negligible and the solubility of the drug in the disperse phase demonstrated to be the main mechanism responsible of CH diffusion. The results obtained suggest that the formation of a crosslinked alginate matrix in the internal phase of HIPREs is a factor that has to be taken into account in the development of controlled drug delivery systems.

Effect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions

The aim of this work was to evaluate the effect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions formed by microfluidization. Emulsions prepared consisted of corn oil and Tween 20 as dispersed phase and sodium alginate solution as continuous phase. In order to obtain nanoemulsion A (NA), both phases were microfluidized together. On the other hand, coarse emulsion without sodium alginate was microfluidized and mixed with a microfluidized (MA) or non-microfluidized (N-MA) sodium alginate solution leading to nanoemulsions B(MA) and B(N-MA), respectively. NA exhibited the smallest particle size (261 nm) and monomodal distributions with a polydispersity index of 0.25. The ζ-potential, viscosity and WI of NA were −37 mV, 22.7 mPa s and 57.28, respectively. Spectroscopic, chromatographic and electron microscopic techniques were used to evaluate changes in microfluidized alginate molecules when they were within emulsions. After microfluidization, alginates suffered depolymerization and further rearrangement, changing the disposition of polymer chains around oil droplets and nanoemulsions characteristics. Thus, these results evidence the significant impact of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions and how it can affect to the stability of the resulting systems which are going to be used as functional ingredients in food matrices.

The effect of calcium chloride concentration on alginate/Fmoc-diphenylalanine hydrogel networks

Peptide based hydrogels gained a vast interest in the tissue engineering studies thanks to great superiorities such as biocompatibility, supramolecular organization without any need of additional crosslinker, injectability and tunable nature. Fmoc-diphenylalanine (FmocFF) is one of the earliest and widely used example of these small molecule gelators that have been utilized in biomedical studies. However, Fmoc-peptides are not feasible for long term use due to low stability and weak mechanical properties at neutral pH. In this study, Fmoc-FF dipeptides were mechanically enhanced by incorporation of alginate, a biocompatible and absorbable polysaccharide. The binary hydrogel is obtained via molecular self-assembly of FmocFF dipeptide in alginate solution followed by ionic crosslinking of alginate moieties with varying concentrations of calcium chloride. Hydrogel characterization was evaluated in terms of morphology, viscoelastic moduli and diffusional phenomena and the structures were tested as 3D scaffolds for bovine chondrocytes. In vitro evaluation of scaffolds lasted up to 14days and cell viability, sulphated glycosaminoglycan (sGAG) levels, collagen type II synthesis were determined. Our results showed that alginate incorporation into FmocFF hydrogels leads to better mechanical properties and higher stability with good biocompatibility.

Designing improved poly lactic-co-glycolic acid microspheres for a malarial vaccine: incorporation of alginate and polyinosinic–polycytidilic acid

Vaccination using proteins and peptides is currently gaining importance. One of the major drawbacks of this approach is the lack of an efficient immune response when the antigens are administered without adjuvants. In this study, we have taken the advantage of a combined adjuvant system in order to improve the immunogenicity of the SPf66 malarial antigen. For that purpose, we have combined poly (lactic-co-glycolic) acid microspheres, alginate, and polyinosinic polycytidilic acid. Our results show that microspheres can enhance the IgG production obtained with Freund’s complete adjuvant. We have attributed this improvement to the presence of polyinosinic polycytidilic acid, since formulations comprising this adjuvant overcame the immune response from the others. In addition, our microspheres produced both IgG1 and IgG2a, leading to mixed Th1/Th2 activation, optimal for malaria vaccination. In conclusion, we have designed a preliminary formulation with a high potential for the treatment of malaria.

RhEGF-loaded PLGA-Alginate microspheres enhance the healing of full-thickness excisional wounds in diabetised Wistar rats

Diabetic foot ulcers (DFUs) represent a major clinical challenge in the ageing population. To address this problem, rhEGF-loaded Poly-Lactic-co-Glycolic-Acid (PLGA)-Alginate microspheres (MS) were prepared by a modified w/o/w-double-emulsion/solvent evaporation method. Different formulations were evaluated with the aim of optimising MSs properties by adding NaCl to the surfactant solution and/or the solvent removal phase and adding alginate as a second polymer. The characterisation of the developed MS showed that alginate incorporation increased the encapsulation efficiency (EE) and NaCl besides increasing the EE also became the particle surface smooth and regular. Once the MS were optimised, the target loading of rhEGF was increased to 1% (PLGA-Alginate MS), and particles were sterilised by gamma radiation to provide the correct dosage for in vivo studies. In vitro cell culture assays demonstrated that neither the microencapsulation nor the sterilisation process affected rhEGF bioactivity or rhEGF wound contraction. Finally, the MS were evaluated in vivo for treatment of the full-thickness wound model in diabetised Wistar rats. rhEGF MS treated animals showed a statistically significant decrease of the wound area by days 7 and 11, a complete re-epithelisation by day 11 and an earlier resolution of the inflammatory process. Overall, these findings demonstrate the promising potential of rhEGF-loaded MS (PLGA-Alginate MS) to promote faster and more effective wound healing, and suggest its possible application in DFU treatment.