Constructing a biofunctionalized 3D-printed gelatin/sodium alginate/chitosan tri-polymer complex scaffold with improvised biological andmechanical properties for bone-tissue engineering

Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.

Chitosan/Sodium Alginate Multilayer pH-Sensitive Films Based on Layer-by-Layer Self-Assembly for Intelligent Packaging

The abuse of plastic food packaging has brought about severe white pollution issues around the world.Developing green and sustainable biomass packaging is an effective way to solve this problem.Hence,a chitosan/sodium alginate-based multilayer film is fabricated via a layer-by-layer(LBL)self-assembly method.With the help of superior interaction between the layers,the multilayer film possesses excellent mechanical properties(with a tensile strength of 50 MPa).Besides,the film displays outstanding water retention property(blocking moisture of 97.56%)and ultraviolet blocking property.Anthocyanin is introduced into the film to detect the food quality since it is one natural plant polyphenol that is sensitive to the pH changes ranging from 1 to 13 in food when spoilage occurs.It is noted that the film is also bacteriostatic which is desired for food packaging.This study describes a simple technique for the development of advanced multifunctional and fully biodegradable food packaging film and it is a sustainable alternative to plastic packaging.

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

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.

Preparation, characterization and in vivo evaluation of alginate-coated chitosan and trimethylchitosan nanoparticles loaded with PR8 influenza virus for nasal immunization

For efficient mucosal vaccine delivery, nanoparticulate antigens are better taken by microfold cells in the nasal associated lymphoid tissue and also dendritic cells. Nanoparticles based on polymers such as chitosan(CHT) and its water soluble derivative, trimethylchitosan(TMC), could be successfully used as carrier/adjuvant for this purpose. Sodium alginate, a negatively charged biopolymer, could modify the immunostimulatory properties of CHT and TMC NPs and increase their stability. Sodium alginate(ALG)-coated chitosan(CHT)and trimethylchitosan(TMC) nanoparticles(NPs) loaded with inactivated PR8 influenza virus were successfully prepared by direct coating of the virus with CHT or TMC polymers to evaluate their immunoadjuvant potential after nasal immunization. After nasal immunizations in BALB/c mice, PR8-CHT formulation elicited higher IgG2 a and Ig G1 antibody titers compared with PR8-TMC. ALG coating of this formulation(PR8-CHT-ALG) significantly decreased the antibody titers and a less immune response was induced than PR8-TMC-ALG formulation. PR8-TMC-ALG formulation showed significantly higher Ig G2 a/Ig G1 ratio, as criteria for Th1-type immune response, compared with PR8-CHT-ALG and PR8 virus alone. Altogether, the PR8-TMC-ALG formulation could be considered as an efficient intranasal antigen delivery system for nasal vaccines.

The Effect of Chitosan and Sodium Alginate on the Root Growth and Enzyme Activity of Soybean

The resaerch examined the effect of the two oceanic materials as coating materials on the soybean growth.The results showed chitosan and sodium alginate seed coating can enhance the growth of seedling root,increase the nodule mumber,root activity and the growth of underground.The suggested coating ratios were 0.5～1.0g/kgseed,the same as chitosan.The two materials could increase the contents of CAT and NR in soybean leaves,decrease the contents of POD in soybean leaves.

Effect of formulation variables on in vitro release of a water-soluble drug from chitosanesodium alginate matrix tablets

The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using trimetazidine hydrochloride(TH)as a water-soluble model drug,influence of dissolution medium,the amount of CSeSA,the CS:SA ratio,the type of SA,the type and amount of diluents,on in vitro drug release from CSeSA based matrix tablets were studied.Drug release kinetics and release mechanisms were elucidated.In vitro release experiments were conducted in simulated gastric fluid(SGF)followed by simulated intestinal fluid(SIF).Drug release rate decreased with the increase of CSeSA amount.CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found.On the other hand,a large amount of water-soluble diluents could modify drug release profiles.It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism.In conclusion,this study demonstrated that it is possible to design extended-release tablets of watersoluble drugs using CSeSA as the matrix by optimizing formulation components,and provide better understanding about drug release from CSeSA matrix tablets.

Culture of yeast cells immobilized by alginate-chitosan microcapsules in aqueous-organic solvent biphasic system

Immobilization biocatalysis is a potential technology to improve the activity and stability of biocatalysts in nonaqueous systems for efficient industrial production.Alginate-chitosan(AC)microcapsules were prepared as immobilization carriers by emulsifi cation-internal gelation and complexation reaction,and their contribution on facilitating the growth and metabolism of yeast cells were testifi ed successfully in culture medium-solvent biphasic systems.The cell growth in AC microcapsules is superior to that in alginate beads,and the cells in both immobilization carriers maintain much higher activity than free cells,which demonstrates AC microcapsules can confer yeast cells the ability to resist the adverse effect of solvent.Moreover,the performance of AC microcapsules in biphasic systems could be improved by adjusting the formation of outer polyelectrolyte complex(PEC)membrane to promote the cell growth and metabolic ability under the balance of resisting solvent toxicity and permitting substrate diffusion.Therefore,these findings are quite valuable for applying AC microcapsules as novel immobilization carriers to realize the biotransformation of value-added products in aqueous-solvent biphasic systems.

The Effect of Chitosan and Sodium Alginate on the Growth and Photosynthesis of Soybean

Seed coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant.Sodium alginate and chitosan are highˉmolecular compound of two different kind,have the characteristic of promoting the crop growth.Using Sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics.The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.50 g·kg -1 .

Influence of coating on the triamcinolone release of alginate chitosan beads for colonic drug delivery

The aim of this study was to evaluate the effect of coating of alginate-chitosan (AL:CS) beads on the colonic drug delivery. The AL:CS systems containing triamcinolone (TC) were coated with the HPMCP and Eudragit? L100 by immersion and by spraying methods. The drug release profile in simulated colonic medium was determined using 5% human fecal content suspension in 0.01 N buffer solution, pH 6.8. The systems coated with HPMCP showed a lower rate of drug delivery in simulated enteric medium. The delivery profile in simulated colonic medium followed zero-order kinetic. The coated systems provided a promising drug-delivery profile for application in colonic drug delivery.

Yerba Mate Extract Encapsulation with Alginate and Chitosan Systems: Interactions between Active Compound Encapsulation Polymers

Yerba mate (Ilex paraguariensis) contains a high amount of polyphenols associated with antiradical activity and possible benefits for preventing degenerative diseases. Natural extracts from this South American herb were encapsulated in calcium alginate and calcium alginate-chitosan beads to be incorporated as an additive in food products. The interactions between the active compound and the polymers were evaluated by Scanning Electron Microscopy (SEM), thermal analysis (Thermo Gravimetric Assays, TGA, and Differential Scanning Calorimetry, DSC) and Fourier Transform Infrared Spectrometry (FT-IR) studies. Also, the effect of these interactions on extract release in a gastrointestinal model system was evaluated. Results showed the interactions between the calcium alginate matrix and the chitosan external layer. Also, interactions between the natural extract and each polymer were observed. In both encapsulation systems the highest polyphenol content was released in simulated gastric fluid. However, capsules coated with chitosan allowed releasing a higher amount of polyphenols into the simulated intestinal fluid. This fact was attributed to both the protection of the chitosan barrier and the strong interaction between yerba mate extract and chitosan.

Leydig Cells Encapsulation with Alginate-Chitosan: Optimization of Microcapsule Formation

This research aimed to optimize the formation of microcapsules from alginate and chitosan for Leydig cells encapsulation. Alginate was used as the first coating agent while chitosan was the second layer. Various concentrations of alginate and CaCl2 were applied utilizing the extrusion method and the best concentration was determined based on their formation time, shape and diameter of microcapsules. Alginate microcapsule was applied with chitosan in various con- centrations. The best chitosan concentration was selected based on its mechanical stability. The results showed that the minimum concentration of alginate was 1.5% (w/v) with viscosity of 33.8 cPs, resulted to spherical microcapsules with diameters of 230 - 270 μm. The optimum concentration of chitosan as the second coating agent was 0.5% (w/v), resulted to spherical microcapsules with mechanical stability of 4 hours. Leydig cells were trapped inside the microcapsule with a density that is proportional to the concentration of cells used in the encapsulation.

Preparation and Characterization of AlginateHyaluronic Acid-chitosan based Composite Gel Beads

The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid（HA） and Chitosan（CS） were successfully admixed with Ca^2＋/alginate（SA） gel system to produce SA/HA/CS gel beads by dual crosslinking： the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA（2%, m/v） to HA（2%, m/v） was kept at 2：1, then the mixture was dripped into the Ca^2＋ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS（LMW-CS） for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca^2＋ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.

Alginate Reinforced Chitosan and Starch Beads in Slow Release Formulation of Imazaquin Herbicide—Preparation and Characterization

In a bid to make slow release formulations of imazaquin, the herbicide was encapsulated in starch and chitosan beads reinforced with alginate. The beads were characterized using SEM, DSC and FTIR. Two types of formulations were made by extrusion into 0.25 M calcium chloride solution: chitosan/alginate (LNCI) and starch/alginate (LNSI) beads, and the third was by gelatinization of starch at 75?C (LNSI2). Findings showed highly porous spherical beads, the starch/alginate beads bigger and less porous than the chitosan/alginate beads with diameters of 2.53 ± 0.01 and 2.31 ± 0.01 mm;porosity of 57.58% ± 0.2% and 81.28% ± 0.2% and swelling of 34.91% ± 0.2% and 80.35% ± 0.2%, respectively. FTIR revealed a reduction in intensity of the carboxylate peaks of alginate and the peak at 1058 cm?1, present in the FTIR of the matrices, is shifted to lower wave-numbers in the formulations, signifying interactions between the formulation components that make for good slow release. The DSC thermograms of all formulations showed evidence of interaction of imazaquin carboxylate group with the N-atoms of the macromolecules, which is indicative of reduced crystallinity of imazaquin.

Uptake of Bile Acid into Calcium-Induced Alginate Gel Beads Containing <i>β</i>-Chitosan Weak Acid Salt

Recently, potential applications for β-chitosan (β-CS) have been examined. In the present study, calcium-induced alginate gel beads (Alg-Ca) containing weak acid salts of β-CS were prepared and examined with regard to their ability to adsorb bile acids in vitro. More than 70% of taurocholate dissolved in solution was taken up by Alg-Ca containing 100 mg β-CS, sim. ilar to the degree of uptake observed with Alg-Ca containing α-CS salt. The adsorption of bile acid was affected by the absolute amount of β-CS and/or the acid concentration of the preparation. A secondary bile acid, taurodeoxycholate, was also adsorbed by Alg-Ca containing weak acid salts of β-CS. Therefore, β-CS might be used to adsorb bile acids within the gastrointestinal tract in the same manner as an anion-exchange resin, and thus serve as a complementary means by which to prevent hyperlipidemia.

Alginate-chitosan conjugated nanoliposome for catechin:Preparation,characterization and stability

Catechin(CTC)is a phenolic active compound with multiple biological activities.However,CTC is relatively unstable,easily oxidized and poorly soluble in water,showing limited bioavailability,which is a challenge for its application in the pharmaceutical and food industry.The purpose of this study was to promote the controlled release of CTC in the simulated gastrointestinal(GI)tract by using biopolymer-coupled nanoliposomes(NL).The nanoliposome was characterized by multifunctional polycrystalline X-ray diffraction(XRD),and Fourier transform infrared spectroscopy(FTIR).The results exhibited that the size of the nanocarrier was in the range of 87-178 nm,the encapsulation efficiency of CTC was 93.5%,and the combination of chitosan(CS)and alginate(ALG)was better than that of monopolymer.In vitro digestion studies showed that ALG-CS-NL significantly controlled the release of CTC by the diffusion,dissolution,and slow release mechanism and retained about 33%-37%of CTC under the GI condition.These results demonstrated that ALG-CS-NL could increase the stability of CTC,which may be important for the development of nutraceutical-enriched functional foods.

Complex Coacervation composed of Polyelectrolytes Alginate and Chitosan

Alginate sodium(ALG)and chitosan(CHI)can form fiber,films,microspheres,hydrogels and all with a wide range of biomedical applications.Few works have been done as a result of the easily flocculation of chitosan in negatively charged matrix.Complex coacervation composed of polyelectrolytes alginate and chitosan were successfully fabricated.The results showed that the lower molecular weights of the chitosan is better for the fabricated of the complex coacervation.

Amphiphilic sodium alginate-vinyl acetate microparticles for drug delivery

To overcome the fast or burst release of hydrophilic drugs from hydrophilic alginate-based carriers,hydrophobic molecule(vinyl acetate,VAc)was grafted on alginate(Alg),which was further used to prepare drug carriers.Amphiphilic Alg-g-PVAc hydrogel beads were firstly prepared by emulsification/internal gelation technique for the loading of bovine serum albumin(BSA).Then,chitosan was coated on the surface of beads to form novel amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules.The BSA-loading amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules display similar morphology and size to the hydrophilic alginate/chitosan(AC)microcapsules.However,the drug loading and loading efficiency of BSA in Alg-g-PVAc/CS microcapsules are higher,and the release rate of BSA from Alg-g-PVAc/CS microcapsules is slower.The results demonstrate that the introduction of hydrophobic PVAc on alginate can effectively help retard the release of BSA,and the higher degree of substitution is,the slower the release rate is.In addition,the complex membrane can also be adjusted to delay the release of BSA.As a whole,amphiphilic sodium alginate-vinyl acetate/CS microparticles could be developed for macromolecular drug delivery.