Containing Chitosan Research Articles

Optical, Functional Impact and Antimicrobial of Chitosan/Phosphosilicate/Al2O3 Nanosheets

A nanosheets containing chitosan (CS) and bioactive P2O5:SiO2/Al2O3 were prepared by the sol–gel method. The nanosheets were characterized by XRD, FE-SEM, FT-IR and optical studies. FE-SEM displayed a nano-clustering and dense structure with promising morphology. The optical results reveal that the incorporation of Al2O3 nanoparticles within the phosphosilicate/chitosan system was successfully cross-linked and create a change in the internal electronic structure. The optical band gap increased from 3.6 to 3.8 eV with increasing Al2O3 content. The antimicrobial effectiveness for chitosan/phosphosilicate/(0.6, 0.9 mol.%)Al2O3 nanosheets exhibited remarkable enhancement in the antimicrobial activities that candidates it for spectroscopic and bio-applications.

Preparation of Bentonite/Chitosan Composite for Bleaching of Deteriorating Transformer Oil.

A novel adsorbent containing chitosan (CS) and bentonite (BT) was developed by mixing, drying, and calcining, and used as an adsorbent for the efficient bleaching of deteriorating transformer oil. The effects of calcination temperature, dosage of CS, adsorbent content, adsorption temperature, and adsorption time on the bleaching capacity of transformer oil were investigated. The structure of the adsorbent was also investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherm techniques. The results showed that there was only physical interaction between CS and BT; CS did transform to carbon (C) and covered the surface of BT. The specific surface area and micropore volume of the adsorbent were affected by the calcination process. The composite adsorbent offered an excellent bleaching performance. When the calcination temperature was 300 °C and dosage of CS was 5%, the composite adsorbent had the optimum bleaching properties. When the composite adsorbent content was 4%, the adsorption temperature was 50 °C and the adsorption time was 75 min, the colour number and transmittance of the deteriorating transformer oil decreased from no. 10 to no. 1 and increased from 70.1% to 99.5%, respectively.

Application of a novel PUB enhanced semi‐interpenetrating chitosan‐based anion exchange membrane

A novel OH− conducting membrane containing chitosan (CS), poly-(acrylamide-co-diallyldimethylammonium chloride) (PAADDA) and linear structured poly-bis (2-chloroethyl) ether-1,3-bis [3-(dimethylamino)propyl] urea copolymer (PUB) was synthesized via a solution-casting method and subsequently modified by hot treatment and chemical cross-linking. The structural characterizations of scanning electron microscope (SEM), atomic force microscope (AFM), Fourier transform infrared spectra (FT-IR), and X-ray photoelectron spectroscopy (XPS) were carried out, showing that CS, PAADDA, and PUB formed a compact interpenetrating polymer network structure without apparent phase separation phenomenon under the help of cross-linking. By changing the content of PUB in the membrane, the application performance such as mechanical properties, thermal gravimetric (TG) analysis, water uptake (WU), OH− conductivity ( ) and ion exchange capacity (IEC) were investigated to evaluate the feasibility for alkaline membrane fuel cells. The maximum OH− conductivity could be reached up to 3.12 × 10−2 S cm−1 at 80°C in a mass ratio of CS/PAADDA/PUB (1:0.5:0.5) while a good tensile strength of 22.73 MPa and an excellent elongation at break of 23.55% could be obtained in a mass ratio of CS/PAADDA/PUB (1:0.5:0.25). Furthermore, the membrane also exhibited relatively high oxidative stability as well as excellent alkaline resistance stability, when conditioned in 30% H2O2 solution at ambient temperature for 120 hours and 8 M KOH solution at 60°C for 320 hours, respectively. Membrane electrode assemblies (MEAs) achieved a peak power density of 38.1 mW cm−2 at the maximum current density of 73.2 mA cm−2 in a H2/O2 system at room temperature. PUB was successfully introduced into the CS-based membrane to improve the conductivity. Maximum OH− conductivity reached 0.016 S cm−1 at room temperature. Tensile strength of the prepared membrane could reach up to 22.73 MPa. The prepared membrane exhibited an excellent elongation at break of 23.55%. The membrane showed good oxidative stability and excellent alkaline resistance stability.

Antioxidant Activity Improvement of Apples Juice Supplemented with Chitosan-Galactose Maillard Reaction Products.

Chitosan-galactose Maillard reaction (CG) were prepared by heating at 100 °C for 3 hrs in a model system containing chitosan (CH) and 1%, 1.5% and 2% (w/v) of galactose. The results showed that the absorbance at 294 and 420 nm, the fluorescence intensity and the color differences of CG Maillard reaction products (MRPs) increased significantly with the increase of galactose concentration, which indicated the development of MRPs. In addition, FT-IR analysis showed that the degree of deacetylation of CG-MRPs was reduced with the increasing galactose ratio by the schiff base (–C=N) formation, indicating that the galactose has been attached to the amino group of chitosan. Likewise, the antioxidant activities (DPPH, chelating ability and reducing power) of CG-MRPs were investigated. Notably, the effect of galactose concentration in CG-MRPs was found to enhance the antioxidant activity, indicating that CG-2% exhibited the highest antioxidant activity in the range of 0.25–2.0 mg/mL. Furthermore, the apple juice supplemented with CG-MRPs could significantly improve the antioxidant activities, and CG-2% in apple juice showed the better antioxidant capacity at the concentration of 1.0 mg/mL. Thus, we conclude that CG-MRPs addition may greatly improve the antioxidant quality of apple juice.

Preparation of chitosan-based composites with urethane cross linkage and evaluation of their properties for using as wound healing dressing

In this research, biocomposite films containing chitosan (CS), polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), with different ratios, have been provided. The effects of adding hexamethylene 1, 6-di(aminocarboxysulfonate) (HMDACS) as cross-linking agent and the formation of urethane linkage on mechanical properties such as tensile strength, elongation and dynamic-mechanical properties such as storage modulus and tan δ were studied. Also, the antibacterial properties of the composites were investigated by viable bacterial cell counting and compared in reducing the bacterial growth. The final results showed the composite containing CS (50 wt%), PVA (30 wt%), PVP (20 wt%) and HMDACS (2 wt%) had the highest mechanical properties. Scanning electron microscopy (SEM) micrographs confirmed uniform distribution of components in the polymer matrix. In general, low contact angle values revealed the hydrophilicity of the prepared films. It was found that the composites made by combining CS, PVA and PVP at concentration of 50, 25, 25 wt% (A3) and 60, 20, 20 wt% (B4), cross-linked with 2 wt% HMDACS, had the best antibacterial activity against Escherichia coli and Staphylococcus aureus, hence they can be used as promising materials for the preparation of wound dressings.

Chitosan/gellan gum ratio content into blends modulates the scaffolding capacity of hydrogels on bone mesenchymal stem cells

Here, we have demonstrated the production and characterization of hydrogel scaffolds based on chitosan/gellan gum (CS/GG) assemblies, without any covalent and metallic crosslinking agents, conventionally used to yield non-soluble polysaccharide-based materials. The polyelectrolyte complexes (physical hydrogels called as PECs) are characterized by Fourier-transform infrared spectroscopy, wide-angle X-ray scattering, and scanning electron microscopy. Hydrogels containing chitosan (CS) excesses (ranging from 60 to 80 wt%) were created. Durable polysaccharide-based scaffolds with structural homogeneity and interconnecting pore networks are developed by modulating the CS/GG weight ratio. The CS/GG hydrogel prepared at 80/20 CS/GG weight ratio (sample CS/GG80-20) is cytocompatible, supporting the attachment, growth, and spreading of bone marrow mesenchymal stem cells (BMSCs) after nine days of cell culture. The cytocompatibility is correlated to the swelling capacity of the PEC in PBS buffer (pH 7.4). By controlling the CS content, we can tune the water uptake of the material, enhancing the capacity to serve as a three-dimensional cell scaffold for BMSCs. This work presents for the first time that CS/GG hydrogels can be applied as scaffolds for tissue engineering purposes.

A biocompatible chitosan-ionic liquid hybrid catalyst for regioselective synthesis of 1,2,3-triazols

A new type of quadruple hybrid system was prepared containing chitosan (CS), folic acid (FA), Poly(styrene-co-maleic anhydride) [SMA] and ionic liquid (IL). This nanocatalyst was synthesized by the functionalization of SMA with folic acid and then polymerization with chitosan in the presence of DCC and NHS. CuI was immobilized onto this support to provide Cu@SMA-FA-CS-IL. The catalyst was fully characterized by using different characterization techniques such as FTIR, 1H NMR, ICP, SEM, EDX, TGA, and XRD. This Cu (I) heterogeneous species was successfully applied in the reaction of sodium azide, terminal alkynes, and alkyl halides or α-haloketones in water to afford 1,4-disubstituted-1,2,3-triazoles within relatively short reaction times. Moreover, the catalyst is recyclable for five reaction cycles with minor CuI leaching and slight drop of the catalytic activity.

Ternary melt blend based on poly (lactic acid)/chitosan and cloisite 30B: A study of microstructural, thermo-mechanical and barrier properties

Abstract In this study, blends were developed based on poly (lactic acid) (PLA) containing chitosan (CHS) extracted in our laboratory and an organically modified montmorillonite (cloisite 30B) at different amounts from 1 to 4 (in wt.-%). Tensile samples were prepared using twin-screw extrusion followed by injection molding, and films were obtained by press compression. The morphological and mechanical results showed a phase segregation and poor adhesion between the polymers. Indeed, the elongation at break and thermal stability had undergone a major decrease when adding chitosan to the PLA matrix. Glass transition temperature (Tg), melt temperature (Tm) and recrystallization temperature (Tc) decreased with the addition of chitosan, whereby an increase in crystallinity indicated a nucleation effect showing the same results as with the addition of cloisite 30B. An interesting effect of cloisite 30B was found when it was incorporated into the PLA/CHS blend especially with respect to a 4 wt.-% of cloisite 30B amount. The loss of elongation at the break was partially compensated and the thermal stability and crystallinity were improved. The water vapor permeability (WVP) and water vapor transmission rate (WVTR) of PLA/chitosan blends were higher than those for the neat PLA. By incorporating the C30B into the PLA/CHS blends, very interesting and good barrier properties were recorded as compared to neat PLA and PLA/CHS composites.

Antioxidant and antimicrobial effects of edible coating based on chitosan and bamboo vinegar in ready to cook pork chops

Edible coating solutions, containing chitosan (CH) and bamboo vinegar (BV), were developed to investigate the effect of CH-BV coating solutions on quality and shelf life of ready to cook (RTC) pork chops stored at 4 ± 1 °C for 12 days. The antioxidant effects against lipid oxidation and antimicrobial activity against total viable counts (TVC), lactic acid bacteria (LAB), Enterobacteriaceae, and Pseudomonus spp. were analyzed. At the same time, Changes in color parameters and sensory attributes of all RTC samples were evaluated. Results showed that CH-BV coating treatments tended to retard lipid oxidation by inhibited the increases in TBARS values. CH coating treatments enhanced L* and maintained a* values almost stable during storage. Compared to the control sample, CH and CH-BV coating treatments maintained the initial color values of samples for a longer period according to DE* values. Based primarily on microbiological and sensory data, CH and CH-BV coating treatments improved shelf-life by ca. 3 and 6 days, respectively. Therefore, bamboo vinegar-based edible coating treatment could be applied to RTC meat products to improve product's shelf life and food safety.

Nano-biocomposite scaffolds of chitosan, carboxymethyl cellulose and silver nanoparticle modified cellulose nanowhiskers for bone tissue engineering applications

In the present work, we aimed to synthesize highly efficient nano-composite polymeric scaffolds with controllable pore size and mechanical strength. We prepared nanocomposite (CCNWs-AgNPs) of silver nanoparticles (AgNPs) decorated on carboxylated CNWs (CCNWs) which serves dual functions of providing mechanical strength and antimicrobial activity. Scaffolds containing chitosan (CS) and carboxymethyl cellulose (CMC) with varying percent of nanocomposite were fabricated using freeze drying method. XRD and FESEM analysis of nanocomposite revealed highly crystalline structure with AgNPs (5.2 nm dia) decorated on ~200 nm long CCNWs surface. FTIR analysis confirmed the interaction between CCNWs and AgNPs. Incorporation of nanocomposite during scaffolds preparation helped in achieving the desirable 80–90% porosity with pore diameter ranging between 150 and 500 μm and mechanical strength was also significantly improved matching with the mechanical strength of cancellous bone. The swelling capacity of scaffolds decreased after the incorporation of nanocomposite. In turn, scaffold degradation rate was tuned to support angiogenesis and vascularization. Scaffolds apart from exhibiting excellent antimicrobial activity, also supported MG63 cells adhesion and proliferation. Incorporation of CCNWs also resulted in improved biomineralization for bone growth. Overall, these studies confirmed excellent properties of fabricated scaffolds, making them self-sustained and potential antimicrobial scaffolds (without any loaded drug) to overcome bone related infections like osteomyelitis.

Chitosan/nano-hydroxyapatite/nano-zirconium dioxide scaffolds with miR-590-5p for bone regeneration

Bone tissue engineering (BTE) relies on biocomposite scaffolds and bioactive molecules for bone regeneration. The present study was aimed to synthesize and characterize biocomposite scaffolds containing chitosan (CS), nano-hydroxyapatite (nHAp) and nano‑zirconium dioxide (nZrO2) along with microRNA (miRNA) for BTE applications. miRNAs act as post-transcriptional regulator of gene expression. The fabricated biocomposite scaffolds were characterized using SEM, FT-IR and XRD analyses. The effect of a bioactive molecule (miR-590-5p) with scaffolds was tested for osteoblast differentiation at the cellular and molecular levels using mouse mesenchymal stem cells (C3H10T1/2). The results showed that CS/nHAp/nZrO2 scaffolds promoted osteoblast differentiation, and this effect was further increased in the presence of miR-590-5p in C3H10T1/2 cells. Thus, we suggested that CS/nHAp/nZrO2 scaffolds with miR-590-5p would have potential towards the treatment of bone defects.

Fabrication of antibacterial chitosan-PVA blended film using electrospray technique for food packaging applications

In this study, blended films from poly(vinyl alcohol) (PVA) containing chitosan (CS) were prepared via a simple solution casting and electrospraying method. The structures of the PVA-CS films were characterized by Fourier-transform infrared spectroscopy. The morphologies of the films were observed by scanning electron microscopy. The thermal properties of the PVA-CS films were examined by thermogravimetry. The effects of CS contents on the mechanical properties, oxygen permeability values, water vapor permeation levels, and antibacterial behaviors against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains were investigated. Compared to the pure PVA film, the PVA-CS films showed greater elongation at break, lower oxygen permeability, higher water barrier properties, and greater antibacterial activity, especially for the PVA:CS weight ratio of 75:25. The obtained results indicate the PVA-CS film may be a promising material for food packaging applications.

Bio-inspired layered chitosan/graphene oxide nanocomposite hydrogels with high strength and pH-driven shape memory effect

The layered nanocomposite hydrogel films containing chitosan (CS) and graphene oxide (GO) have been prepared by water evaporation induced self-assembly and subsequent physical cross-linking in alkaline solution. The layered CS/GO hydrogel films obtained have a nacre-like brick-and-mortar microstructure, which contributes to their excellent mechanical properties. The tensile strength and elongation at break of the hydrogel films with 5wt% GO are 5.35MPa and 193.5%, respectively, which are comparable to natural costal cartilage. Furthermore, the CS/GO hydrogel films exhibited pH-driven shape memory effect, and this unique phenomenon is mainly attributed to the reversible transition of partial physically cross-linking corresponding to hydrogen bondings and hydrophobic interactions between CS polymer chains due to pH changing.

A novel electrochemical determination for the anti-osteoporosis drug (alendronate sodium) and its application for corrosion monitoring of surgical 316 L SS bone implant

Low cost and simply produced electrochemical silver nanoparticles modified graphene oxide (SNMGO) sensor was constructed to monitor 1 mM Alendronate sodium (ALN) drug. The corrosion behavior of surgical 316 L stainless steel (SS) as bone implant in simulated body fluid (pH 7.4) coated with a novel nano-composite coating, containing Chitosan (CS), TiO2 nanoparticles (TO) and multi-walled carbon nanotube (CNT) was monitored. Cyclic voltammetry, Differential pulse voltammetry, Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were used in ALN electrochemical determination using SNMGO sensor and to detect the corrosion behavior of nano-composite coat (CS/TONP/CNT) in simulated body fluid (SBF). Scanning electron microscope (SEM) and energy dispersive X-Ray analysis (EDX) techniques were done to confirm both sensor and corrosion results.

Fabrication and evaluation of thermosensitive chitosan/collagen/α, β-glycerophosphate hydrogels for tissue regeneration

Thermosensitive hydrogels whose physiological properties are similar to extracellular matrix have been extensively used for tissue regeneration. Polysaccharides and proteins, as biocompatible substrates similar to bio-macromolecules that could be recognized by human body, are two preferred polymers for fabrication of such hydrogels. A series of novel thermosensitive hydrogels (CS-ASC-HGs) containing chitosan (CS) and acid-soluble collagen (ASC) were thus prepared, in the presence of α, β-glycerophosphate, to mimic extracellular microenvironment for tissue regeneration. Rheological measurements demonstrated excellent thermosensitivity. FT-IR and SEM indicated CS-ASC-HGs possessed 3D porous architectures with fibrous ASC, and the molecular structure of ASC was well-maintained in hydrogels. Hemolysis, acute toxicity, and cytotoxicity tests suggested CS-ASC-HGs were of good biocompatibility. CS-ASC-HGs were able to support the survival and proliferation of L929 cells encapsulated in them. Moreover, CS-ASC-HGs had better pH stability and biocompatibility than pure CS hydrogel. These results suggested that CS-ASC-HGs could serve as promising scaffolds for tissue regeneration.

Effect of Fully Biobased Coatings Constructed via Layer-by-Layer Assembly of Chitosan and Lignosulfonate on the Thermal, Flame Retardant, and Mechanical Properties of Flexible Polyurethane Foam

A fully biobased coating containing chitosan (CS) and lignosulfonate (LS) was facilely fabricated on the surface of flexible polyurethane foam (FPUF) using layer-by-layer assembly method. The CS/LS based coatings were successfully deposited on the substrate, as demonstrated by UV–vis absorption spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, and scanning electron microscopy. Subsequently, the different bilayers of the coatings were applied to enhance the thermal stability, fire resistance, and mechanical properties of FPUFs. It was found that the thermal degradation of coated FPUF under nitrogen atmosphere was obviously retarded compared with the pure FPUF. Furthermore, an eight-bilayer CS/LS based coating significantly improved the fire resistance of FPUF, as evidenced by the remarkable reduction (42%) of peak heat release rate. Meanwhile, the mechanical property of coated FPUF was improved. After the FPUF was covered with the eight-bilayer coating, the tensile strength was increased from 0.17 to 0.19 MPa compared with pure FPUF.

Inhibitor encapsulated, self-healable and cytocompatible chitosan multilayer coating on biodegradable Mg alloy: a pH-responsive design.

The design of functional biomaterials that respond intelligently to external stimuli has become a rapidly growing area with widespread interest. This work contributes to the development of a feedback-active anticorrosion system with intriguing self-healing ability to protect magnesium (Mg) from biocorrosion. The system was constituted by an inner micro/nano-porous, ceramic-like pre-coating developed readily from the substrate, and an outermost inhibitor (nanosized cerium (Ce) oxides) containing chitosan (CS) multilayers. Here, the pre-coating acted as both an "anchoring" and a "barrier" layer to acquire structural integrity and improved impedance, respectively. Green CS served as cargo for Ce to be entrapped, harnessing Ce-NH2 complexation chemistry. The coating barrier properties were evaluated by electrochemical impedance spectroscopy. The active corrosion inhibition was assessed by immersion degradation tests with respect to Mg2+ release, pH alteration, crack development, and scanning Kelvin potential. To our delight, the coatings effectively protected the substrate from biocorrosion in vitro compared with bare alloys. Putatively, the pH-triggered formation of Ce oxide precipitation, along with the pH-buffering activity and movable swelling capacity of CS macromolecules, should have contributed to restraining the anodic activity and healing the cracks/defects dynamically. Furthermore, the coated substrate had the biocompatibility to elicit better attachment and growth of osteoblasts.

Preparation and characterization of bio-based hybrid film containing chitosan and silver nanowires

A bio-based hybrid film containing chitosan (CS) and silver nanowires (AgNWs) has been prepared by a simple casting technique. X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV–visible spectroscopy were employed to characterize the structure of bio-based film. The bio-based hybrid film showed unique performance compared with bare chitosan film. The incorporated nano-silver could improve the strength properly. The results revealed that AgNWs in CS film, improved its tensile strength more than 62% and Young modulus 55% compared with pure chitosan film. On the other hand tensile strength was increased 36.7% with AgNPs. Importantly, the film also exhibited conductivity and antibacterial properties, which may expand its future application.

Scaffolds containing chitosan/carboxymethyl cellulose/mesoporous wollastonite for bone tissue engineering

Scaffold based bone tissue engineering utilizes a variety of biopolymers in different combinations aiming to deliver optimal properties required for bone regeneration. In the current study, we fabricated bio-composite scaffolds containing chitosan (CS), carboxymethylcellulose (CMC) with varied concentrations of mesoporous wollastonite (m-WS) particles by the freeze drying method. The CS/CMC/m-WS scaffolds were characterized by the SEM, EDS and FT-IR studies. Addition of m-WS particles had no effect on altering the porosity of the scaffolds. m-WS particles at 0.5% concentration in the CS/CMC scaffolds showed significant improvement in the bio-mineralization and protein adsorption properties. Addition of m-WS particles in the CS/CMC scaffolds significantly reduced their swelling and degradation properties. The CS/CMC/m-WS scaffolds also showed cyto-friendly nature to human osteoblastic cells. The osteogenic potential of CS/CMC/m-WS scaffolds was confirmed by calcium deposition and expression of an osteoblast specific microRNA, pre-mir-15b. Thus, the current investigations support the use of CS/CMC/m-WS scaffolds for bone tissue engineering applications.

Preparation of magnetite-chitosan/methylcellulose nanospheres by entrapment and adsorption techniques for targeting the anti-cancer drug 5-fluorouracil

In this work, we have formulated novel nanospheres that could be used in the controlled release of the anticancer drug, 5-fluorouracil (5-FU). The nanospheres are composed of magnetite, containing chitosan (CS) and methylcellulose (MC). The drug entrapment was achieved through the encapsulation and adsorption processes. The effects of the preparation conditions, such as magnetite content, CS/MC ratio, crosslinking concentration, exposure time to glutaraldehyde (GA), and the drug/polymer ratio were investigated for both processes. The 5-FU release was found to follow the Fickian mechanism, and the Langmuir isotherm for the nanospheres was achieved through encapsulation and adsorption processes, respectively.