Range Of Chitosan Concentrations Research Articles

Encapsulation efficiency and oral delivery stability of chitosan–liposome‐encapsulated immunoglobulin Y

The degradation of acidic gastric juice on immunoglobulin Y (IgY) leads to destruction on the structural and loss of the bioactivity, limiting the bioavailability of oral IgY and its research or application in adjuvant treatment of diseases. In this work, it was surmounted with IgY-loaded chitosan-liposomes prepared by supercritical carbon dioxide-assisted method. A range of chitosan concentrations (0%, 0.5%, 0.8%, 1.1%, and 1.4%) were selected to explore the influence of chitosan concentration on the encapsulation effectiveness, stability, and in vitro-simulated digestive release properties of liposome-encapsulated IgY. The results displayed that owing to the robust interaction between chitosan and liposomes, the particle size, encapsulation efficiency, and stability of liposomes reached the optimal state at a chitosan concentration of 0.8%, with the encapsulation efficiency reaching 77.51%. Moreover, the liposomes could be stored at 4°C for 9 days without obvious sedimentation. The zeta potential of liposomes containing 0.8% chitosan was higher than that of samples without chitosan at high salt concentration treatment. In vitro release experiments demonstrated that liposomes fitted well in the Peppas equation. Chitosan-coated liposomes were capable of delaying the release of IgY in the stomach during simulated digestion, allowing more IgY to be released in the intestine. To sum up, Chitosan played a vital role in maintaining the stability and encapsulation of IgY, and the results of this work provide a theoretical basis for the development and utilization of chitosan and the protection of activity of IgY when administered orally. PRACTICAL APPLICATION: IgY serves as a bioactive substance with anti-inflammatory, antibacterial, and antioxidant functions. However, it is far from satisfactory for the oral delivery activity of IgY. Encapsulation of liposomes contributed to alleviate the release of IgY in the stomach. However, liposomes were less stable and not efficient enough to encapsulate IgY. This study demonstrated that the addition of 0.8% chitosan could effectively enhance the encapsulation efficiency of liposomes and improved the stability of liposomes. It might contribute to the solution of the oral delivery activity of IgY and provide a promising idea for the utilization of chitosan.

Chitosan biostimulant controls infection of cucumber by Phytophthora capsici through suppression of asexual reproduction of the pathogen

The biopolymer chitosan is a derivative of chitin, which can promote plant growth and protect plants from phytopathogens. This study aimed to evaluate the efficacy of chitosan as a biostimulant and a biorational agent to protect cucumber plants from damping-off disease caused by <em>Phytophthora capsici</em>. Cucumber seeds were treated with a range of chitosan concentrations, viz. 0, 125, 250, and 500 ppm, to evaluate effect on seed germination and fresh root and shoot weight of the seedlings. Chitosan significantly (<em>p</em> ≤ 0.05) enhanced seed germination and root and shoot growth of cucumber in a dose-dependent manner up to 500 ppm. Application of in vitro chitosan suspension onto <em>P. capsici</em> mycelial plug suppressed growth of mycelia, formation of sporangia, and release of <em>P. capsici</em> zoospores at 125–500 ppm concentrations. Cucumber seedlings from chitosan-treated seeds showed enhanced resistance to damping-off disease caused by <em>P. capsici</em> compared to untreated control. Cucumber seedlings from 500 ppm chitosan seed treatment showed 100% disease resistance against damping off caused by <em>P. capsici</em>. These results suggest that chitosan could be used as a natural and environmentally safe alternative to a synthetic growth promoter and pesticide for sustainable production of cucumber.

Coprecipitation of microamounts of radionuclides on chitosans of various molecular weights in solutions

Coprecipitation of 233U, 239Pu, 241Am, 152Eu, 90Sr, 90Y, and 60Co on chitosans of various molecular weights (MW) was studied. Low-molecular-weight chitosan (LMWC) with MW of 5 kDa (5 × 103 g mol−1) proved to be a more effective coprecipitant than high-molecular-weight chitosan (HMWC) with MW of 700 kDa (7 × 105 g mol−1). With HMWC, the degree of coprecipitation (α) was 80% for 152Eu and 90Y, 99% for 233U and 241Am, and 85% for 239Pu. For 60Co, α monotonically increased with an increase in the chitosan concentration in solution and reached 40% at [HMWC] = 5 g l−1. For 90Sr, α did not exceed 3% in the entire examined range of chitosan concentrations. With LMWC, the α values for An, 152Eu, and 90Y differed insignificantly (92–99%). For 60Co and 90Sr, α increased to 40% in the range of chitosan concentrations from 0 to 1 g l−1. The presence of inorganic salts in solution considerably decreases α of UO 2 2+ with chitosans but does not noticeably affect the behavior of Am, Pu, and Eu. The effect of salts on the efficiency of 233UO2/2+ coprecipitation on HMWC decreases in the order Na2SO4 > NaCl > Na2CO3 > NaNO3 > Na3PO4. Based on the results obtained, a procedure suitable for expedition conditions was developed for preconcentration of Pu from seawater on chitosan, with simultaneous separation of Pu from U, for radioecological monitoring of natural waters. The specific activity of Pu in samples of near-bottom seawater of gulfs of the Novaya Zemlya archipelago was (150–170) ± 20 mBq m−3. The results are well consistent with the published data.

Effect of molecular weight and degree of deacetylation of chitosan on the formation of oil-in-water emulsions stabilized by surfactant–chitosan membranes

The objective of this study was to establish the influence of polyelectrolyte characteristics (molecular weight and charge density) on the properties of oil-in-water emulsions containing oil droplets surrounded by surfactant–polyelectrolyte layers. A surfactant-stabilized emulsion containing small droplets ( d 32 ≈ 0.3 μm ) was prepared by homogenizing 20 wt% corn oil with 80 wt% emulsifier solution (20 mM SDS or 2.5 wt% Tween 20, 100 mM acetate buffer, pH 3) using a high-pressure valve homogenizer. This primary emulsion was then diluted with various chitosan solutions to produce secondary emulsions with a range of chitosan concentrations (3 wt% corn oil, 0–1 wt% chitosan). The influence of the molecular characteristics of chitosan on the properties of these emulsions was examined by using chitosan ingredients with different molecular weights (MW ∼ 15, 145, and 200 kDa) and degree of deacetylation (DDA ∼ 40, 77, and 92%). The electrical charge and particle size of the secondary emulsions were then measured. Extensive droplet aggregation occurred when the chitosan concentration was below the amount required to saturate the droplet surfaces, but stable emulsions could be formed at higher chitosan concentrations. The ζ-potential and mean diameter ( d 32 ) of the particles in the secondary emulsions was not strongly influenced by chitosan MW, however the chitosan with the lowest DDA (40%) produced droplets with smaller mean diameters and ζ-potentials than the other two DDA samples examined. Interestingly, we found that stable multilayer emulsions could be formed by mixing medium or high MW chitosan with an emulsion stabilized by a non-ionic surfactant (Tween 20) due to the fact the initial droplets had some negative charge. The information obtained from this study is useful for preparing emulsions stabilized by multilayer interfacial layers.