Preparation Of Chitosan Research Articles

Preparation of Chitosan Molecularly Imprinted Polymers and the Recognition Mechanism for Adsorption of Alpha-Lipoic Acid.

Two effective molecularly imprinted polymers for the adsorption of alpha-lipoic acid (ALA) were synthesized by the cross-linking of chitosan with epichlorohydrin (ECH) and glutaraldehyde (GLU), respectively, in the presence of ALA as template molecules. Investigations on the molar ratios of ALA and chitosan (–NH2) in the preparation of chitosan molecularly imprinted polymers (MIPs) were carried out with a factor of ALA rebinding capabilities. The surface morphology and chemical properties of the polymers were characterized. The optimized MIPs crosslinked by ECH (MIPs–ECH) and MIPs crosslinked by GLU (MIPs–GLU) had adsorption capabilities of 12.09 mg/g and 19.72 mg/g for ALA, respectively. The adsorption behaviors of two kinds of chitosan MIPs including adsorption kinetics and isotherms were investigated in detail. Adsorption and kinetic binding experiments showed that the prepared MIPs–ECH and MIPs–GLU had selective adsorption and excellent affinity for ALA. In addition, the possible binding models between ALA and chitosan oligosaccharide were predicted by molecular dynamics simulation.

Preparation of chitosan based magnetic nanocomposite for tetracycline adsorption: Kinetic and thermodynamic studies

In the present study, the magnetic nanocomposite is fabricated using chitosan, thiobarbituric acid, malondialdehyde and Fe3O4 nanoparticles (CTM@Fe3O4). The fabricated nanocomposite (CTM@Fe3O4) is characterized using FTIR, TGA, BET, XRD, Raman, XPS, FESEM, and HRTEM techniques. The results of BET analysis confirmed that the nanocomposite has a mesoporous structure with high surface area of 376 m2 g−1 and high pore volume 0.3828 cm3 g−1. The adsorption of tetracycline (TC) onto CTM@Fe3O4 adsorbent is carried out using batch technique by changing several factors such as pH, concentration, contact time, and temperature. Langmuir and pseudo-second-order nonlinear models were found to be the best-fit models to predict isotherms and kinetics of adsorption, respectively. The highest adsorption capacity of 215.31mg/g was achieved at the optimum conditions of 0.05g adsorbent dosage, 60mg/L TC concentration. Overall, results demonstrated that CTM@Fe3O4 nanocomposite was an excellent adsorbent material with superparamagnetic properties, which allowed the separation as well as recovery of the adsorbent from aqueous solution using external magnet for effective industrial applications.

Preparation of Elastic and Antibacterial Chitosan-Citric Membranes with High Oxygen Barrier Ability by in Situ Cross-Linking.

Chitosan–citric biomembranes Ch-CA-Gx (x = 0–3) were prepared by a simple cross-linking. The dependence of mechanical property, water-resisting capacity, microstructural characteristic, oxygen barrier ability, and thermal properties of membranes on the content of glycerin was investigated. The results revealed that vacuum drying at 80 °C can lead to low-yield amidation and the Maillard reaction, thus affecting the thermal stability and water resistance of biomembranes. Owing to the ionic cross-linking and amidation, the chitosan–citrate complex showed weaker compatibility when the glycerin content increased, thereby leading to discontinuity of microstructure in the Ch-CA-Gx (x = 1–3) membranes, which was in line with the weaker mechanical properties and water-resisting abilities of membranes, compared to Ch-CA-G0. Chitosan membranes showed interestingly high oxygen barrier capabilities under 40 and 80% relative humidity (RH) conditions, probably attributed to the increased diffusion length arising from the hydrogen-bonding, ionic, and covalent cross-linking. The oxygen transmission rates of Ch-CA-Gx were below 0.1 cm3 m–2 day–1 at 40% RH. The Ch-CA-Gx membranes showed a good elasticity assigned to the reversibly cross-linked structure. The membranes presented strong antibacterial activities against Staphylococcus aureus and Escherichia coli bacteria, probably owing to the citric acids. The results demonstrated that these materials have potential applications as membranes or protecting coatings for food packaging and successful cross-linking by means of amidation, and the Maillard reaction under the condition of vacuum drying can be probably applied as a green and alternative method for the fabrication of mechanically tough and antibacterial membranes, fibers, and gels.

Preparation of chitosan, sunflower and nano-iron based core shell and its use in dye removal

Preparation of chitosan, sunflower and nano-iron based core shell and its use in dye removal

Analysis of the Adsorption of Toxic Chromium (VI) by Untreated and Chitosan Treated Banana and Areca Fiber

This paper work involves bunch experiments to investigate the effect of contact time, pH, and adsorbent dose on the extent of adsorption by bio-composites. Adsorption capacity of Chromium (VI) onto chitosan coated with banana and areca fiber was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH and adsorbent dose. The chitosan and fibers (banana and areca) were then cross-linked with glutaraldehyde to remove chromium [Cr (VI)] from water via static adsorption. It was found that optimum chromium absorption capacity of chitosan was assessed at pH of 2.5 to 4.5 and contact time of 30 to 180 minutes for raw banana and areca fiber and for chitosan treated banana & areca fiber. Though optimum adsorption of chromium of chitosan was measured 34.17 ppm (85.42%) from a 100 ml solution containing 40 parts per million (ppm) of Cr (VI) at 120 minutes, pH of 3.0 and 120 milligram (mg) adsorbent dose size, use of composite will be more favorable in the point of environmental concern as well as low cost because chitosan preparation is comparatively costly then banana and areca fiber. On the other hand, untreated banana and areca fiber optimum adsorption of chromium measured 3.65 ppm (9.1%) at 180 min and, pH of 4.5 and 140 mg adsorbent dose size and 3.76 ppm (9.4%) at 180 min, pH of 4.5 and 160 mg adsorbent dose size respectively. In case of chitosan treated banana fiber, it was observed that adsorption was increased from 17.664 to 30.057 (75.14%). On the other hand, for areca fiber with chitosan, it was observed that adsorption was increased from 21.664 to 30.156 (75.39%) ppm. The Langmuir and Freundlich adsorption models were used for the mathematical description of the adsorption of chromium ion onto composites and it was found that the Langmuir adsorption isotherm was more fitted models which mean that a monolayer adsorption surface was created. After analyzing from IBM SPSS 25 software, we got the standard deviation value of adsorbed Cr by raw chitosan, untreated banana and areca of pH test results were 9.399, 1.072, 0.728 ppm, time test results were 2.163, 0.859, 0.896 ppm and adsorbent dose test results were 6.588, 0.966, 1.211 ppm correspondingly. The standard deviation results of pH, time and amount of treated banana fiber test results were 1.831, 2.693 and 5.469 ppm congruently. On the other hand, the standard deviation results of pH, time and amount of treated areca fiber test results were 3.293, 2.673 and 4.152 ppm individually. Fourier transform infrared (FT-IR) spectroscopy analysis indicated that both amino and hydroxyl groups of chitosan, banana and areca fiber were engaged in the adsorption.

Preparation and Characterization of Chitosan obtained from Pacific White Shrimp Shells and its in vitro Antifungal Activity

In this article, a method for the processing of chitosan from Pacific white shrimp shells is developed which involves three steps viz. demineralization, deproteinization, and deacetylation. The samples of chitosan with more than 90% degree of deacetylation (DD%) were obtained by FTIR. This indicated that the current processing method of shrimp shells was beneficial for chitosan production. The morphology of chitosan sample was determined using scanning electron microscopy (SEM). X-ray diffraction (XRD) patterns exhibited two peaks of crystalline character approximately at 10º and 20º (2θ). The effect of 0.1% (w/v) of chitosan on the growth of Penicillium digitatum was tested by an in vitro assay and the results showed an almost complete inhibition (98% ± 0.56).

壳聚糖基复合膜的制备及其抗氧化性能的研究

壳聚糖基复合膜的制备及其抗氧化性能的研究

Evaluation of antibacterial activity of chitosan against different bacterial strains

The present study is related to new green and low cost technical method for wastewater treatment using chitosan as natural material. Chitosan was prepared from chitin of the seafood’s shell (Procambrus clarkia). Preparation of chitosan was carried out by a chemical process involving demineralization, deproteinization and deacetylation. Chitosan is largely known for its activity against a wide range of microorganisms. Antibacterial effect of different doses of chitosan (0.09, 0.2, 0.4, 0.6 and 0.8 g) on Escherichia coli (E. coli) bacteria in the secondary treated wastewater samples was studied. The secondary treated wastewater was collected from Zenein wastewater treatment plant. Also the effectiveness of chitosan on Enterococcus faecalis, Bacillus subtillus, Staphylococcu saureus (gram +ve bacteria), Escherichia coli, Enterobacter aerogenes (gram –ve) was evaluated by the reduction in total bacterial count of each strain in synthetic media. The study was extended to measure the antibacterial activity (inhibition zone) of chitosan on E. coli by the poured plate method. The results indicated that the optimum conditions at which 99.98% removal for all types of bacteria were 0.6 g chitosan, contact time 30 min and shaking 250 rpm. According to the obtained results, the most acceptable antimicrobial mechanism is found to include the presence of charged groups in the polymer backbone and their ionic interactions with bacterial wall constituents. It could be concluded that chitosan could be used for disinfection of the secondary treated wastewater.

Preparation of Chitosan and Glycol Chitosan Coated Magnetic Nanoparticles Loaded with Carboplatin as Anticancer Drug

Surface modified Fe3O4 nanoparticles (Fe3O4-OA) with an average diameter of 10 nm were synthesized, coated by chitosan (CS) and glycol chitosan (GCS), thus magnetic polymer nanocomposites were obtained. The magnetic nanostructures were analyzed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and vibrating sample magnetometer (VSM). All magnetic structures synthesized in this study exhibited superparamagnetic properties. Loading carboplatin (CPt) as anticancer drug to Fe3O4-OA-GCS nanocomposites were carried out with 13.17 % drug content and 38 % encapsulation efficiency. The cytotoxicity studies were occured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on L929 mouse fibroblasts and MCF-7 human breast cancer cells. Fe3O4-OA-GCS-CPt nanocomposites showed higher cytotoxicity than free CPt on the MCF-7 cells at 50 µg/ml drug concentrations during 72 h.

Preparation and characterization of chitosan from crab shell (Portunus trituberculatus) by NaOH/urea solution freeze-thaw pretreatment procedure

The effect of NaOH/urea solution freeze-thaw pretreatment to the chitosan of purity and the degree of deacetylation from the crab shell was examined. Higher purity chitosan (CS1) was prepared. On this basis, the raw materials after the first demineralization were pretreated with NaOH/urea solution freeze-thaw under different freeze-thaw situations. The produced chitosans (CS1-CS4) were characterized in the ash content, solubility, protein content, degree of deacetylation, viscosity average molecular weight, SEM, FTIR, XRD, antimicrobial activity. The results showed that the freeze-thaw process had advantageous influence on decreasing the ash content and increasing degree of deacetylation and antibacterial activity. Moreover, the antibacterial property of the extracted chitosans seemed to be positively related to their degree of deacetylation. It is concluded that CS4 had the lowest ash content (0.052%), the highest degree of deacetylation (86.02%) and the greatest antibacterial activity. Therefore, we recommend CS4 as agent for industrial and pharmaceutical applications.

Preparation of chitosan modified magnetic carbon nanotubes and application in immobilized enzymes

ABSTRACTChitosan (CTS) was selected to combine Fe3O4/CNTs with noncovalent bonds to prepare CTS modified magnetic carbon nanotubes (CTS-Fe3O4/CNTs). The chemical structure, morphology, crystal structure, element and magnetic properties were analyzed by means of FTIR, TEM, XRD, XPS and VSM. CTS-Fe3O4/CNTs was used as immobilized enzyme carrier for the degradation of phenolic compounds in sewage. The results of characterizations demonstrated that CTS had successfully modified the surface of Fe3O4/CNTs, amino groups existed simultaneously on the surface of Fe3O4 and CNTs. The surface modification of CTS did not destroy the crystal structure of Fe3O4/CNTs and CTS-Fe3O4/CNTs had super paramagnetic property. The effects of preparation and reaction conditions of CTS-Fe3O4/CNTs immobilized enzyme were investigated. Compared with free enzyme, the carrier CTS-Fe3O4/CNTs immobilized enzyme restricted conformational change of enzyme and stabilized enzyme relative activities, enhanced higher temperature tolerance, wider pH value, repeated using times and storage time under the optimum conditions of immobilized enzyme.

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings.

As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay against Escherichia coli and Staphylococcus aureus indicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.

Preparation of polyvinyl alcohol, chitosan and polyurethane-based pH-sensitive and biodegradable hydrogels for controlled drug release applications

In this study, novel hydrogels containing poly(azomethine-urethane) (PAMU), PVA and CS were prepared for controlled drug delivery application. FT-IR was used to confirm hydrogel structures. Thermal stability and mechanical behavior of the hydrogels were also investigated by using a thermogravimetric analysis (TG-DTA) and mechanical measurements. Swelling degree of the hydrogels were carried out at pH = 3, 7, and 12. Antibacterial properties of the hydrogels were also investigated using disc diffusion method. The obtained results showed that controlled drug release, swelling performance, and mechanical properties of the hydrogels were enhanced by increasing the amount of PAMU in the hydrogel matrix.

Cellulosic fibres modified by chitosan and synthesized ecofriendly carboxymethyl chitosan from prawn shell waste

The present study investigates preparation, characterization, and application of chitosan (Ch) and its derivative, carboxymethyl chitosan (CMCh), on jute and cotton fibres through the eco-friend modification avoiding chemical modifier. Chitosan is a deacetylated product of chitin. CMCh was produced from prepared chitosan (89% degree of deacetylation) by carboxymethylation process, and confirmed by Fourier transform infrared (FTIR) spectroscopy. CMCh had an average degree of substitution ranging from 0.62 to 1.20 was determined by titrimetric analysis. X-ray diffraction of CMCh showed a less ordered arrangement than chitosan. Moisture content and ash content of Ch and CMCh were 10%, 9% and 2.33%, 14.39%, respectively which affect cellulosic fibre properties. Extracted chitosan and CMCh were used as surface modifier for natural cellulosic fibres. Modification of jute and cotton through sorption of chitosan and CMCh introduces amino (1610 cm−1) and carboxyl groups (1737 cm−1) on the cellulose chain of fibre surface, causes functionalization. The modified fibres were characterized by FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Again, dyed modified fibres showed 10–15% higher dye exhaustion, and better fastness properties than that of unmodified fibres.

Facile preparation of EDTA-functionalized magnetic chitosan for removal of co(II) from aqueous solutions

ABSTRACT In this study, an efficient adsorption and reusable magnetic ligand material (Fe3O4@Chitosan-EDTA) was synthesized by binding EDTA dianhydride onto magnetic chitosan, and it was employed in removal of Co(II) from aqueous solution. The maximum adsorption capacity of Co(II) onto Fe3O4@CS-EDTA was 48.78 mg/g at pH = 5 (303 K), which is much higher than that of Fe3O4@Chitosan as well as chitosan. The kinetics of Co(II) on the Fe3O4@CS-EDTA was consistent with the pseudo-second-order model. The equilibrium data were better fit with the Langmuir isothermal model than with the Freundlich isothermal model, suggesting that the adsorption mechanism was chemical monolayer homogeneous adsorption. The thermodynamic data showed that the sorption of Co(II) was spontaneous. Furthermore, after four cycles, the adsorption capacity of Co(II) onto the Fe3O4@CS-EDTA still retained 84.5% of the capacity of the fresh adsorbent, indicating that Fe3O4@CS-EDTA can be considered a promising recyclable adsorbent to remove heavy-metal ions from wastewater.

Preparation of Chitosan, Sodium Alginate, Gelatin and Collagen Biodegradable Sponge Composites and their Application in Wound Healing and Curcumin Delivery

This research aimed to produce three chitosan-based biodegradable sponge composites from collagen, gelatin, and sodium alginate and through addition of curcumin to investigate their biological effects on wound healing. To this end, the Chitosan-Collagen-Curcumin (Chs, Col, Cur), Chitosan-Gelatin-Curcumin (Chs, Gel, Cur), and Chitosan-Alginate-Curcumin (Chs, Alg, Cur) sponge composites were prepared and subject to FT-IR, SEM, TGA, water absorption, biodegradability, wound healing and anti-bacterial analyses. Based on the results, the highest and lowest water absorptions were associated with Chitosan-Alginate-Curcumin and Chitosan-Collagen-Curcumin composites, respectively. Moreover, according to the SEM images, the highest porosity and the largest cavity size were associated with the Chitosan-Alginate-Curcumin composite. The biodegradability analysis results revealed that Chitosan-Alginate-Curcumin was completely destroyed in 4 days, while the Chitosan-Collagen-Curcumin composite showed the lowest level of destruction. Moreover, the highest amount of curcumin was released by the Chitosan-Gelatin-Curcumin composite which happened during the first hour. Finally, the highest wound healing effect was achieved within a 10-day period using the Chitosan-Gelatin-Curcumin composite, completely healing the wound on the mouse skin. On the other hand, the lowest effect was associated with the Chitosan-Alginate-Curcumin composite. The antibacterial tests suggested that all composites exhibited anti-bacterial capabilities, the highest level of which was associated with the Chitosan-Gelatin-Curcumin composite. Moreover, based on the histological tests, the fastest tissue repair process with the highest quality was achieved using the Chitosan-Gelatin-Curcumin sponge composite.

Preparation and Characterization of Chitosan–Alginate Polyelectrolyte Complexes Loaded with Antibacterial Thyme Oil Nanoemulsions

Biomedical industries are attempting to utilize natural materials, as they are bio-compatible, non-toxic, and show bioactive properties, like antimicrobial activity. In this study, natural polyelectrolyte complexed chitosan/alginate films (PECs) were prepared via a casting/solvent evaporation technique, and their characteristics and drug release properties were investigated. PEC films made with two different overall polymer contents, 0.4 and 1 w/v%, were loaded with thyme oil nanoemulsion as drug carrier. The structure of the films was studied by FTIR and optical and scanning electron microscopy. Prepared PEC films had good mechanical and water vapor permeability properties. Release of the thyme oil from the pH-sensitive PEC films (TM-PEC) was detected and followed by UV spectroscopy. The results indicated that the drug release rate of TM-PEC films was the fastest when the chitosan content was 1 %w/v, and various mathematical models were analyzed for investigating the drug release mechanism. Antibacterial tests were performed by counting the number of surviving gram-negative and gram-positive bacteria. The in vitro test indicated the limitation Escherichia coli (E. coli) and Staphylococcus aureus (S.aureus) growth in the presence of TM-PEC films. The MTT test showed more cell viability of the TM-PEC film in comparison with that of the PEC film without TM. Based on the measured physical and antibacterial properties, the chitosan–alginate PEC films loaded with antibacterial essential oils can be considered for biomedical applications, such as wound dressings or controlled release systems.

Application of supercritical gel drying method on fabrication of mechanically improved and biologically safe three-component scaffold composed of graphene oxide/chitosan/hydroxyapatite and characterization studies

Multicomponent-porous scaffolds have recently gained much attention in bone tissue engineering applications due to their ability to mimic the composite structure of natural bone tissue. In the present study, it was aimed to fabricate biologically safe and mechanically improved three-component scaffolds for bone tissue engineering applications. This is the first original report on the application of supercritical gel drying for the fabrication of three-component scaffolds composed of graphene oxide (GO) synthesized by Improved Hummers Method, chitosan (CS) and hydroxyapatite (HAp) derived from eggshells. The phase, morphology, mechanical property and in-vitro biocompatibility of scaffolds were investigated by FTIR, XRD, SEM, TEM, BET, TGA, Universal Instron Mechanical Test System, and MTT testing. For the preparation of scaffolds, GO, CS and HAp solutions were blended at various ratios. Resulting mixtures were molded, frozen, exposed to water-acetone substitution procedure, and dried by supercritical gel drying, respectively. Then, dried scaffolds were subjected to MTT testing for cytotoxicity analysis to examine toxicity effect of GO. Results revealed dose-dependent cytotoxicity effect of GO on MC3T3-E1 cell line. The highest relative cell viability was observed with three-component scaffold composed of GO:1wt%, CS:39wt% and HAp:60wt%. According to characterization studies, this original report demonstrated that scaffold produced with the mentioned procedure had a three-dimensional porous sponge-like structure, highest relative cell viability, and increased mechanical compressive strength compared to other scaffolds fabricated. These properties enable scaffold with combined improvement in biological and mechanical properties to be a promising candidate for application in bone tissue materials.

Chitosan/Disperse Dye Nanoparticles for Concomitant Printing and Antibacterial Finishing

Innovation concerned with hybridization of nanosiezed chitosan with nanoparticles of a disperse dye under the onset of sonication was studied. Three techniques were outlined describing the nanoparticles preparations of chitosan, disperse dye and chitosan /disperse dye nanoparticles. Thus obtained hybrid nano colorant auxiliary was found to possess different hydrophobic/hydrophilic characteristics as well as variable color intensity depending upon the ratio of the disperse dye in the chitosan/dye mix. When applied to textile fabrics (flax, polyester, and polyester/flax blend) as per the pigment printing technique, the nano colorant hybrid display multifunction antibacterial activity and coloration ability. The prepared nanoparticles of chitosan/ disperse dye were characterized using TEM and XRD. The coloured hybrid was applied in textile printing using silk screen technique. The printed samples were evaluated by measuring colour strength, fastness properties, means of print fixation and antibacterial activity.

Therapeutic efficacy of chitosan preparations for lesions of the skin of animals

Therapeutic efficacy of chitosan preparations for lesions of the skin of animals