Chitosan Poly Research Articles

Bis(2-chloroethyl) ether-1,3-bis[3-(Dimethylamino)propyl]urea copolymer -Chitosan–Poly(acrylamide-co-diallyldimethylammonium chloride) Blends as Membranes for Alkaline Anion-Exchange Membranes

Alkaline anion-exchange membranes were prepared from chitosan, Poly(acrylamide-co-diallyldimethylammonium chloride) and Bis(2-chloroethyl) ether-1,3-bis[3-(Dimethylamino)propyl]urea copolymer by blending, then chemical cross-linking using glutaraldehyde(GA) as the cross-linking agent (CS/PAADDA/PUB).The membranes were prepared with different concentration solution consisting of PUB. The OH- conductivity of the membranes was found to be increased with increasing mass ratio of PUB, achieved high up to 1.60×10-2S cm-1 at room temperature. Moreover, The OH- conductivities were all gradually increased with increasing temperature, where the maximum OH- conductivity of 2.35×10-2 S cm-1 was obtained at 80oC. In addition, it reveals the fact that by tuning the mass ratio of CS, PAADDA and PUB from 1:0.5:0.25 to 1:0.5:1 in the membrane, the membrane achieves relatively high extensibility (at break in the range of 14 ~ 23%) and tensile stress (at break around 6 ~ 17 MPa) at about ∼50% relative humidity.

Fabrication and Testing of PVA/Chitosan Bilayer Films for Strawberry Packaging

Strawberry packaging based on four different chitosan–poly(vinylalcohol) blend films with chitosan contents of 0 wt %, 20 wt %, 25 wt %, and 30 wt % was tested. The samples were stored at 18 ± 2 °C and 60% ± 5% relative humidity for six days. Strawberry quality was evaluated during and after storage. Strawberries packaged using these films showed significant differences in weight loss and firmness, decay percentage, titratable acidity, total soluble solids, and ascorbic acid content when compared to non-packaged strawberries. The 25 wt % bilayer film showed the best performance in terms of delaying changes in strawberries. The findings suggest that these 25 wt % chitosan films can used to extend strawberry shelf lives while maintaining quality levels.

Nanocomposite films based on chitosan–poly(vinyl alcohol) and silver nanoparticles with high antibacterial and antioxidant activities

Abstract The present study focused on the synthesis of chitosan–silver nanocomposite films (CSNFs) due to their potential application in various domains including wound dressing, packaging and water purification. Silver nanoparticles (Ag NPs) were generated in-situ by using UV-irradiation and chitosan (CS) as both reductant and stabilizer. FTIR spectra revealed that the primary amine and amide groups of chitosan have specific interactions with nanoparticles surface. The diameter of AgNPs ranged from 170 to 200 nm as determined by DLS and TEM observation. Furthermore, CSNFs were tested for their biological activities and results showed higher antioxidant and antibacterial activities than chitosan film, which increased with AgNPs amount, suggesting that surface structures of chitosan strongly influence the adsorption of AgNPs and the antimicrobial activities. These observations indicate that nanocomposite films have potential applications as anti-infectious wound dressing. Many studies reported the toxicity of AgNPs and their health and environmental risks. For that purpose, cytotoxicity of CS–AgNPs was performed by MTT assay on Chinese hamster ovary R(CHO-K1) cell lines. Results showed that CS–AgNPs have no-cytotoxicity effect, which suggests the possibility of CS–AgNPs uses in foods and biomedical applications.

Convenient approach to making nanocomposites based on a chitosan–poly(vinyl pyrrolidone) polymer matrix and a graphene nanofiller

ABSTRACTConducting, mechanically durable, elastic nanocomposite films were prepared with chitosan (CS) as the polymer matrix, graphene obtained from highly exfoliated graphite as the nanofiller, and poly(vinyl pyrrolidone) (PVP) as the stabilizer of the graphene sheets. The maximum graphene content in the composites without a loss of uniformity and other useful properties increased up to 4.0 wt %. The resulting composites were characterized by scanning electron microscopy, Raman spectroscopy, X‐ray diffraction analysis, mechanical testing, and electrical conductivity testing to determine the effects of the addition of graphene on the morphology and mechanical and electrical properties of the CS–PVP–graphene nanocomposite films. In this study, we took an approach to making nanocomposites from the perspectives of green chemistry, environmental protection, regenerative medicine, and low cost. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45038.

Formation and structure of chitosan–poly(sodium methacrylate) complex nanoparticles

ABSTRACTInterpolyelectrolyte complex (IPEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions, at different carboxyl-to-aminium molar ratios, rCA. Gyration radius was determined by small angle x-ray scattering (SAXS) and showed that, as rCA was increased, IPEC dimensions decreased and reached a minimum at rCA = 0.75, which was considered the ratio at which IPEC cluster dimensions were minimum, following collapse, phase segregation, nucleation, and growth of larger particles. Pair distance distributions, P(r), became narrower up to rCA = 0.75, increasing its width from this point. Relaxation-related parameters from dynamic light scattering (DLS) intensity correlation functions (ICFs) identified three main relaxation processes. The fast process, related to free polyelectrolyte molecules random motion disappeared as rCA, was increased. The other two relaxation processes also were a function of rCA and presented marked changes at rCA = 0.75. At the same value of rCA, the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of IPEC-related interactions. As hydrodynamic diameter, determined by DLS, was much larger than the gyration radius determined by SAXS, IPEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by IPEC soluble clusters, possibly in the form of water-rich gels.

Chitosan-Poly(caprolactone) Nanofibers for Skin Repair.

Dermal wounds, both acute and chronic, represent a significant clinical challenge and therefore the development of novel biomaterial-based skin substitutes to promote skin repair is essential. Nanofibers have garnered attention as materials to promote skin regeneration due to the similarities in morphology and dimensionality between nanofibers and native extracellular matrix proteins, which are critical in guiding cutaneous wound healing. Electrospun chitosan-poly(caprolactone) (CPCL) nanofiber scaffolds, which combine the important intrinsic biological properties of chitosan and the mechanical integrity and stability of PCL, were evaluated as skin tissue engineering scaffolds using a mouse cutaneous excisional skin defect model. Gross assessment of wound size and measurement of defect recovery over time as well as histological evaluation of wound healing showed that CPCL nanofiber scaffolds increased wound healing rate and promoted more complete wound closure as compared with Tegaderm, a commercially available occlusive dressing. CPCL nanofiber scaffolds represent a biomimetic approach to skin repair by serving as an immediately available provisional matrix to promote wound closure. These nanofiber scaffolds may have significant potential as a skin substitute or as the basis for more complex skin tissue engineering constructs involving integration with biologics.

In vitro and in vivo investigation of chitosan–polylysine polymeric nanoparticles for ovalbumin and CpG co-delivery

A simple and powerful vaccine delivery system was developed by electrostatic binding of chitosan-based polycation methoxy poly(ethylene glycol)–chitosan–poly(l-lysine) (mPEG–CS–PLL) with ovalbumin (OVA) and cytosine–phosphate–guanine (CpG).

Synthesis and characterization of chitosan–poly(acrylamide–co-acrylic acid) magnetic nanocomposite hydrogels for use in catalysis

A novel hydrogel based on chitosan–poly(acrylamide-co-acrylic acid) (CAA) with different formulations were synthesized by the effect of gamma radiation. The magnetic CAA hydrogels were also synthesized and characterized by using different techniques, e.g., TEM and XRD. The prepared hydrogels and magnetic hydrogel nanocomposite were utilized for in situ cobalt nanoparticle preparation and employed as a reaction media in catalytic reduction of 2-nitrophenol (2-NP), to 2-aminophenol (2-AP). The experimental parameters that affect the reduction rates such as temperature and amount of catalyst were also, investigated.

Incorporation of graphene oxide into a chitosan–poly(acrylic acid) porous polymer nanocomposite for enhanced lead adsorption

This study describes the successful incorporation of graphene oxide into a chitosan–poly(acrylic acid) polymer blend to obtain porous hydrogel nanocomposite beads with higher lead removal and regeneration capability than any other chitosan hydrogel material or activated carbon.

Synthesis and characterization of an injectable and self-curing poly(methyl methacrylate) cement functionalized with a biomimetic chitosan–poly(vinyl alcohol)/nano-sized hydroxyapatite/silver hydrogel

Preparation and characterizations of injectable p-PMMA/CS–PVA/Nano-HA/Ag+ cements.

Facile synthesis of glucose-sensitive chitosan–poly(vinyl alcohol) hydrogel: Drug release optimization and swelling properties

The study describes the development of glucose-sensitive hydrogel and optimization of bovine serum albumin release profile from the hydrogel. To enhance the glucose sensitivity and improve the swelling behaviors of the hydrogel system, boric acid crosslinking, and freeze-thawing cycle techniques were used to prepare chitosan–poly(vinyl alcohol) hydrogel. The structure of the resultant hydrogel was confirmed by scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental results revealed that the swelling of the hydrogel was influenced by the pH of the medium, and the hydrogel displayed explicit glucose-sensitivity under physiological conditions. The values of the diffusion exponent range between 0.34 and 0.44 and the diffusion of water into the gel system are assumed to be pseudo-Fickian in nature. Under optimized conditions, the cumulative Bovine serum albumin (BSA) drug releases ranged between 69.33±1.95% and 86.45±1.16% at 37°C in the presence of glucose and pH 7.4, respectively.

Composite hydrogel of chitosan–poly(hydroxybutyrate-co-valerate) with chondroitin sulfate nanoparticles for nucleus pulposus tissue engineering

Intervertebral disc degeneration, occurring mainly in nucleus pulposus (NP), is a leading cause of low back pain. In seeking to mitigate this condition, investigators in the field of NP tissue engineering have increasingly studied the use of hydrogels. However, these hydrogels should possess appropriate mechanical strength and swelling pressure, and concurrently support the proliferation of chondrocyte-like cells. The objective of this study was to develop and validate a composite hydrogel for NP tissue engineering, made of chitosan–poly(hydroxybutyrate-co-valerate) (CP) with chondroitin sulfate (CS) nanoparticles, without using a cross linker. The water uptake ability, as well as the viscoelastic properties of this composite hydrogel, was similar to native tissue, as reflected in the complex shear modulus and stress relaxation values. The hydrogel could withstand varying stress corresponding to daily activities like lying down (0.01MPa), sitting (0.5MPa) and standing (1.0MPa) under dynamic conditions. The hydrogels were stable in PBS for 2 weeks and its stiffness, elastic and viscous modulus did not alter significantly during this period. Both CP and CP–CS hydrogels could assist the viability and adhesion of adipose derived rat mesenchymal stem cells (ADMSCs). The viability and chondrogenic differentiation of MSCs was significantly enhanced in presence of CS nanoparticles. Thus, CS nanoparticles-incorporated chitosan–PHBV hydrogels offer great potential for NP tissue engineering.

Metal ions doped chitosan–poly(acrylic acid) nanospheres: Synthesis and their application in simultaneously electrochemical detection of four markers of pancreatic cancer

In this work, a one-pot method was designed to synthesize copper ions, cadmium ions, lead ions and zinc ions doped chitosan-poly(acrylic acid) nanospheres. Those nanospheres can not only produce independent electrochemical signals, but also react with glutaraldehyde (GA) to immobilize different labeled antibodies. Using the modified nanospheres as immunoprobes, a sandwich-type immunosensor was fabricated to simultaneous detection of four tumor markers (CEA, CA199, CA125 and CA242) of pancreatic cancer. This designed immunosensor exhibited good linear relationships in range from 0.1 to 100ng mL(-1) for CEA, 1 to 150UmL(-1) for CA199, CA125 and CA242, corresponding detection limits 0.02ng mL(-1), 0.4UmL(-1), 0.3UmL(-1) and 0.4UmL(-1), respectively. Meanwhile, the immunosensor was applied in analysis of clinical serum samples, whose results were well agreed with the enzyme-linked immunosorbent assay (ELISA), indicating that the proposed immunosensor gave a hope for the identification and validation of specific early cancer.

New trimethyl chitosan-based composite nanoparticles as promising antibacterial agents

In the present study, densely dispersed silver nanoparticles (Ag NPs) were rapidly green synthesized in the presence of Rumex dentatus aqueous extract, followed by UV-irradiation reduction. The Ag NPs were characterized using UV–vis spectroscopy, FTIR, XRD, and TEM. Then, the Ag NPs were incorporated into interpenetrating polymeric networks based on cationic trimethyl chitosan (TMCS) and anionic poly(acrylamide-co-sodium acrylate) copolymer to develop a new series of composite nanoparticles as potential antibacterial agents. Both TMCS and poly(acrylamide-co-sodium acrylate) were prepared in the study, and characterized using FTIR, DSC, and SEM. The synthesized Ag NPs showed high purity and uniform particle size distribution with particle size ranged between 5 and 30 nm. The composite nanoparticles demonstrated homogeneous spherical shape with size in the range of 378–402 nm. Both Ag NPs and the composite nanoparticles showed promising bactericidal activity as compared with the control. Moreover, the antibacterial activity of the composite nanoparticles increased along with increasing the concentrations of Ag NPs and the TMCS.

Mechanical properties and permeability of porous chitosan–poly(p-dioxanone)/silk fibroin conduits used for peripheral nerve repair

Some poly(p-dioxanone) (PDO) homopolymers were first synthesized and the selected PDO was conjugated onto chitosan using a group-protecting method to produce chitosan–poly(p-dioxanone) (CH–PDO) copolymers with various PDO percentages changing from around 30 to 60wt%. The CH–PDO with the PDO content of around 42wt% was used to blend with prescribed amounts of silk fibroin (SF) to build porous single-lumen conduits that are intended to be used for long-gap peripheral nerve repair. Some genipin-crosslinked CH–PDO/SF conduits were endowed with an average porosity of around 60% in their porous wall, and with changed pore-sizes varying from around 10 to ca. 70μm using optimized processing conditions. After being degraded in a PBS medium containing a certain amount of lysozyme for various periods up to 8 weeks, some optimal CH–PDO/SF conduits were able to retain their compressive load and deformation recovery at around 59N/m and 73% in wet state, respectively. In addition, the achieved CH–PDO/SF conduits allowed the permeation of nutritional molecules with various molecular weights while showing a certain ability to prevent cells from infiltrating through the conduit wall. Cell culture confirmed that the optimized CH–PDO/SF conduits were able well supported the growth of rat glioma C6 cells. These results suggest that presently developed CH–PDO/SF conduits have promising potential for long-gap peripheral nerve repair.

Intracellular siRNA delivery dynamics of integrin-targeted, PEGylated chitosan–poly(ethylene imine) hybrid nanoparticles: A mechanistic insight

Integrin-targeted nanoparticles are promising for the delivery of small interfering RNA (siRNA) to tumor cells or tumor endothelium in cancer therapy aiming at silencing genes essential for tumor growth. However, during the process of optimizing and realizing their full potential, it is pertinent to gain a basic mechanistic understanding of the bottlenecks existing for nanoparticle-mediated intracellular delivery. We designed αvβ3 integrin-targeted nanoparticles by coupling arginine–glycine–aspartate (RGD) or RGD peptidomimetic (RGDp) ligands to the surface of poly(ethylene glycol) (PEG) grafted chitosan–poly(ethylene imine) hybrid nanoparticles. The amount of intracellular siRNA delivered by αvβ3-targeted versus non-targeted nanoparticles was quantified in the human non-small cell lung carcinoma cell line H1299 expressing enhanced green fluorescent protein (EGFP) using a stem-loop reverse transcription quantitative polymerase chain reaction (RT-qPCR) approach. Data demonstrated that the internalization of αvβ3-targeted nanoparticles was highly dependent on the surface concentration of the ligand. Above a certain threshold concentration, the use of targeted nanoparticles provided a two-fold increase in the number of siRNA copies/cell, subsequently resulting in as much as 90% silencing of EGFP at well-tolerated carrier concentrations. In contrast, non-targeted nanoparticles mediated low levels of gene silencing, despite relatively high intracellular siRNA concentrations, indicating that these nanoparticles might end up in late endosomes or lysosomes without releasing their cargo to the cell cytoplasm. Thus, the silencing efficiency of the chitosan-based nanoparticles is strongly dependent on the uptake and the intracellular trafficking in H1299 EGFP cells, which is critical information towards a more complete understanding of the delivery mechanism that can facilitate the future design of efficient siRNA delivery systems.

Grafting of prepared chitosan–poly(propylene) imines dendrimer hybrid as a biopolymer onto cotton and its antimicrobial property

Cotton was successfully treated by chitosan––dendrimer PPI hybrid (CS–PPI) using pad-dry-cure method. Scanning electron microscope (SEM), Fourier transform infra red (FTIR) and weight gain analysis clearly confirmed that CS–PPI was grafted on cotton through the formation of new chemical bonds. Due to the presence of CS–PPI on the surface of cotton, the weight gain of cotton was ∼6% increased, and consequently the antimicrobial activity of the treated fabrics under optimum conditions was raised. As a worthy phenomenon, the treated cotton with CS–PPI in a concentration of 20% on the weight of the fabric was shown 100% of bacterial reduction.

Modulating the elution of antibiotics from nanospongy titanium surfaces with a pH-sensitive coating

Fraction of vancomycin eluted at 3 different pHs from bare nanospongy titanium (left) and from nanospongy titanium coated with uncross-linked (center, CH:PEG) and cross-linked (right, CH:PEG + GEN) chitosan–poly(ethylene glycol.

Hydrogen peroxide treated graphene as an effective nanosheet filler for separation application

In this research, H2O2 treated graphene was used as a nanofiller in a chitosan–poly(vinyl pyrrolidone) blend matrix to develop membranes that were tested for PV dehydration of ethanol as a function of filler loading, feed composition and temperature.

Covalent Bond Formation in the Reaction of Glucosamine as Monomer Unit of Chitosan Macromolecules and Poly(ethylene glycol) Disuccinate at Elevated Temperature

Covalent Bond Formation in the Reaction of Glucosamine as Monomer Unit of Chitosan Macromolecules and Poly(ethylene glycol) Disuccinate at Elevated Temperature