Feasibility Of Chitosan Research Articles

Improvements in barrier properties of poly(lactic acid) films coated with chitosan or chitosan/clay nanocomposite

AbstractThe feasibility of chitosan or/and clay coatings as an alternative oxygen barrier material to poly(lactic acid) (PLA) film was investigated. The coated films were composed of natural materials based on biodegradable and biocompatible polymers, which exhibit excellent oxygen‐barrier properties compared with neat PLA films. Thus, these films can contribute toward effectively reducing environmental pollution. The chitosan/clay nanocomposite solutions were effectively dispersed through the clay using an ultrasonic bath and homogenizer. The barrier and morphology properties of the PLA films were tested by measuring selected film properties such as oxygen transmission rate (OTR), water vapor transmission rate (WVTR), field emission scanning electron microscopy, X‐ray diffraction and transmission electron microscope. OTR values measured using the chitosan and chitosan/clay nanocomposite coatings were significantly lower than those measured for neat PLA film. WVTR values measured using chitosan/clay nanocomposite coatings were also lower than those measured for neat PLA film and PLA film coated with chitosan. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Radiolabeling of folic acid-modified chitosan with 99mTc as potential agents for folate-receptor-mediated targeting

The feasibility of chitosan (CS) as a backbone for the design of (99m)Tc-labeled targeting agent was evaluated in this study. Chitosan-folate conjugate (CSFA) and chitosan-folate dithiocarbamate (CSFADTC) were synthesized, characterized and radiolabeled with (99m)Tc as model compounds for folate-receptor (FR) targeting. (99m)Tc-complexes were prepared with high radiochemical purity and high stability. The hydrophilicities of these (99m)Tc-complexes were determined by partition coefficient experiments. The results of biodistribution in normal mice showed that the folic-acid modified agents ((99m)Tc-CSFA and (99m)TcN-CSFADTC) had obviously higher uptake in FR-positive kidney and much lower liver and spleen uptakes than that of non-folic-acid modified (99m)Tc-agent, and the kidney uptakes of FA-modified agents could be blocked significantly by the corresponding cold ligand. Furthermore in vitro and in vivo specific studies will be done in cell line and tumor bearing mice to confirm the usefulness of this chitosan backbone for FR targeting agent design.

Sorption of acid dyes onto GLA and H 2SO 4 cross-linked chitosan beads

The feasibility of chitosan and cross-linked chitosan beads as efficient adsorbents for the removal of Acid Blue 25 (AB 25) and Acid Red 37 (AR 37) from aqueous solution was studied by using batch adsorption techniques. Glutaraldehyde (GLA) and sulphuric acid were employed as cross-linking reagents. The effect of process parameters like pH, agitation period, agitation rate and concentrations of dyes on the extent of AR 37 and AB 25 adsorption by chitosan and cross-linked chitosan beads was investigated. The best interpretation for the equilibrium data was given by the Langmuir isotherm, while the pseudo-second-order kinetic model could best describe the adsorption of these acid dyes. Thermodynamic parameters such as enthalpy change (Δ H°), free energy change (Δ G°) and entropy change (Δ S°) were estimated and adsorption process was spontaneous and exothermic. The desorbed chitosan, chitosan–GLA and chitosan–H 2SO 4 beads can be reused to adsorb the acid dyes. Results also showed that chitosan, chitosan–GLA and chitosan–H 2SO 4 beads were favourable adsorbers.

The influence of chitosan on physico-chemical properties of chicken salt-soluble protein gel

The feasibility of chitosan as cold-set binder in a model with chicken salt-soluble proteins (SSP) was investigated. The parameters studied were molecular weight (MW), percent degree of deacetylation (%DD), and concentration of chitosan, each at three levels (low, medium, and high). The cold-set gels were formed by mixing various preparations of chitosan with 8% w/v SSP and setting at 4 °C for 24 h. The physico-chemical properties of the developed gels, i.e. color, rheological characteristics, texture, disulfide content, non-denaturing gel–electrophoresis pattern, and gel structure, were determined. Chitosan can act as cold-set binder when using in the form of alkali-precipitate. The MW, %DD and concentration significantly affected all of the characteristics of cold-set SSP gel. The inclusion of chitosan resulted in improvement of texture ( p<0.05), increasing of the disulfide content ( p<0.05), and improvement of the rheological characteristics and structure of cold-set SSP gel, while the pattern on non-denaturing gel–electrophoresis remained unchanged. However, the inclusion of chitosan also increased the lightness and paleness ( p<0.05). The appropriate characteristics of chitosan giving the best cold-set gel was chitosan with MW of 1.84×10 5 Da, 94%DD at the concentration of 1.5% by weight.

Rheology of chitosan-kaolin dispersions

Rheological properties of kaolin dispersions have been analyzed as a function of kaolin/chitosan mass ratio. Zeta potential measurements characterized the particles as negatively charged, resulting in the feasibility of chitosan (a cationic polyelectrolyte) adsorption on their surface. The rheological behavior of the dispersions was markedly pseudoplastic and a simple power-law was not able to describe it. The pseudoplastic character of the dispersions was a function of the shear rate, decreasing with its increase. The decrease in pseudoplasticity was related to the disruption of interparticle interactions by shear.