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In this study, zirconium(IV)-chitosan (Zr-CTS) hydrogel beads were synthesized for boron(III) removal. Zr-CTS was characterized by a series of experimental techniques, including SEM, XRD and FTIR. Kinetic, isotherm, and thermodynamic investigations were employed to understand the adsorption behavior. It was found that boron removal is a pH-dependent process, having the highest performance at pH 6–7...
The drying behavior of blade casting aqueous chitosan solution was investigated by means of a custom designed real time characterization system that can track the thickness, weight, temperature and in-plane and out-of-plane birefringence. Beyond a critical solvent concentration, initially isotropic cast solution rapidly develops optical anisotropy as detected by out of plane birefringence measurement...
Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to examine the impact of hydrogen bonding on the reactive amine and hydroxyl groups of chitosan. Measurements were performed on powder and film samples hydrated under different conditions. To resolve the individual OH and NH bands that overlap in the region between 3000 and 3800 cm−1, the spectra were deconvoluted...
Aiming the obtainment of materials with useful properties for bio-applications, as thermal and mechanical (in particular flexibility), chitosan and low molecular weight poly(lactic acid) were chosen due to their biodegradability and biocompatibility in various bio-environments. Networks formed by oligo(dl-lactic acid) segments linked to the chitosan chains were prepared, in which the ratio between...
A novel glucose-sensitive chitosan–polyethylene oxide (CS/PEO = 1:0.5–1:2.5) hydrogel with controlled release of metronidazole (MNZ) was obtained by chemical cross-linking and immobilization of glucose oxidase (GOx). The hydrogel was characterized by Fourier-transformed infrared spectroscopy (FTIR), compressive mechanical test, rheological analysis, cytotoxicity test, and antibacterial test against...
In the following is described the combination of straight biochemical and organic routes to graft nucleotide sequences to a chitosan backbone. The resulting chitosan-g-ssDNA hybrid self-assembles into submicrometer size structures in dilute aqueous solution as assessed by atomic force and electron microscopy imaging. The hypothesis of self-assembly driven by chemical incompatibility between the amphiphilic...
Multicellular spheroids (MCSs) are in vitro tissue models having important biomedical applications. The MCS generation is usually time-consuming because most MCS fabrication methods exploit the inherent ability of cells to self-assemble to form spheroids. Here we tried to accelerate the MCS generation by chemical pre-aggregation of the cells. We first developed a method to chemically aggregate cells,...
Chitosan based polyseudorotaxane was designed as a pH-responsive supramolecular polymeric shell around the mesoporous silica-coated magnetic graphene oxide (Fe3O4@GO@mSiO2). It was used for doxorubicin delivery at cancerous tissue in a controlled manner. The core-shell nanocarrier was formed due to electrostatic interaction between chitosan and carboxylated surface of Fe3O4@GO@mSiO2. The maximum release...
Using electrospinning technique to prepare chitosan (CS) nanofibers from an inexpensive solvent such as acetic acid has been a challenge, due to the lack of sufficient entanglements in these semi-rigid polyelectrolytes. Incorporating polymers such as poly(methacrylic acid) (PMAA) into the solution lowers the entanglement concentration of the polymers, and make all three morphology regimes (polymer...
A novel and facile strategy to modify chitosan (CTS) with a wide catalog of well-defined molecular weight graft hydrophilic and hydrophobic polymers and copolymers via nitroxide-mediated polymerization (NMP) in homogeneous media is reported. This strategy involves three steps: functionalization of CTS with glycidyl methacrylate (GMA) and sodium dodecylbenzenesulfonate (SDBS) to yield CTS-SDBS-g-GMA,...
In this study, the deposition of a homogeneous chitosan layer on the surface of a 3D interconnected porous network of poly(ε-caprolactone) (PCL), prepared from a co-continuous polymer blend of PCL/PEO (poly(ethylene oxide)), was achieved. A Layer-by-Layer (LbL) self-assembly of polyelectrolytes (PDADMAC as polycation and PSS as polyanion) followed by chitosan deposition was compared with a traditional...
A series of plasticised chitosan-based materials and nanocomposites were successfully prepared by thermomechanical kneading. During the processing, the montmorillonite (MMT) platelets were fully delaminated. The nanoclay type and content and the preparation method were seen to have an impact on the crystallinity, morphology, glass transition temperature, and mechanical properties of the samples. When...
The aggregation of chitosan (CS) has been studied as a function of concentration, degree of acetylation (DA), and degree of polymerization (DP) by means of pyrene fluorescence and rheology. Fluorescence experiments show that aggregation of CS involves hydrophobic domains (HD) which are more favoured as lower the DA and DP. Consistent with these results, the viscosity of CS solutions decreases continuously...
Chitosan nanoparticles were obtained by crosslinking with two biocompatible dicarboxylic acids: polyethylene glycol dicarboxylic acid and tartaric acid. The water-in-oil (W/O) microemulsion method yielded particle sizes around 10–15 nm in the dried state (TEM) and 200–700 nm in the swollen state (QELS) from commercial chitosan. All the synthesized nanogels showed improved water solubility and most...
Nanocomposites of chitosan are produced using graphene sulphonic acid (SG) at five different compositions and are designated as SG0.5, SG0.75, SG1, SG3 and SG5; the numbers indicate weight percent of SG. The TEM & AFM micrographs indicate that the SG sheets are in exfoliated state. The thermal stability and the storage modulus of the composites increase with increasing SG concentration showing...
In this paper, unzipped multiwalled carbon nanotube oxides (UMCNOs), obtained by oxidation unzipping multiwalled carbon nanotubes (MWNTs) were used as novel nanofillers for mechanical reinforcement of chitosan (CS) matrix. The UMCNOs/CS nanocomposite films with different amounts of UMCNOs were fabricated by solution-casting the mixtures of UMCNOs and CS acetic acid aqueous dispersions. The structures...
A degradation controllable composite material was designed to resist the degradation rate variation caused by pH change. The degradation controllable composite materials were prepared by incorporating lysozyme-loaded Ca-alginate microparticles into chitosan matrix. In these materials, the Ca-alginate microparticle carriers can fast release large amount of lysozyme at higher pH to compensate the decrease...
A highly deacetylated (97.5%) chitosan in 50% acetic acid was electrospun at moderate temperatures (25–70 °C) in the presence of a low content of polyethylene oxide (10 wt% PEO) to beadless nanofibers of 60–80 nm in diameter. A systematic quantitative analysis of the solution properties such as surface tension, conductivity, viscosity and acid concentration was conducted in order to shed light on...
The miscibility of Chitosan (CS) and poly(ethylene oxide) (PEO) in their blends and the effect of K + and Ca 2+ doping on the CS/PEO interaction have been investigated in this work. CS and PEO appeared to be miscible and the DSC analysis suggested the Flory–Huggins interaction parameter χ AB to be −0.21. Doping of K + and Ca 2+ into the CS/PEO blend matrix enhanced...
Through the assembly of polyelectrolyte in aqueous emulsion, we synthesized a series of core–shell ionic complex nanoparticles containing anionic polyurethane (PU) and cationic chitosan (CS). The physicochemical properties of PU–CS ionic complex (PU-c-CS) materials were investigated by IR, XPS, DLS, TEM, AFM, general tensile tests, and surface contact angle measurement. It was found that the sizes...
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