Impact of Degree of Ionization and PEGylation on the Stability of Nanoparticles of Chitosan Derivatives at Physiological Conditions.

Nowadays, the therapeutic efficiency of small interfering RNAs (siRNA) is still limited by the efficiency of gene therapy vectors capable of carrying them inside the target cells. In this study, siRNA nanocarriers based on low molecular weight chitosan grafted with increasing proportions (5 to 55%) of diisopropylethylamine (DIPEA) groups were developed, which allowed precise control of the degree of ionization of the polycations at pH 7.4.

Amphiphilic diethylaminoethyl chitosan of high molecular weight as an edible film.

Edible films and coatings can enhance the quality of food products, protecting them from biological deterioration, especially against fungal diseases and pathogenic microorganisms. In this study, films from chitosan, diethylaminoethyl-chitosan (DEAE-CH) and its hydrophobicized derivative DEAE-CH-DD were prepared by casting and their physicochemical and antimicrobial properties evaluated. The grafting with DEAE and dodecyl groups resulted in films with an elasticity modulus up to five times higher than commercial chitosan and increased water vapor permeability.

Biopolymeric Films of Amphiphilic Derivatives of Chitosan: A Physicochemical Characterization and Antifungal Study.

The chemical modification of chitosan has been an active subject of research in order to improve the physicochemical and antifungal properties of chitosan-based films. The aim of this study was to evaluate the physiochemical and antifungal properties of films prepared with chitosan and its derivatives containing diethylaminoethyl (DEAE) and dodecyl groups (Dod). Chitosans and selected derivatives were synthesized and characterized, and their films blended with glycerol and sorbitol (5%, 10%, and 20%).

Amphipathic chitosans improve the physicochemical properties of siRNA-chitosan nanoparticles at physiological conditions.

Chitosan has received a lot of attention as a carrier for small interfering RNA (siRNA), due to its capacity for complexation and intracellular release of these molecules. However, one of its limitations is its insolubility at neutral pH and the tendency towards aggregation of its nanoparticles in isotonic ionic strength. In this study, a series of amphipathic chitosans were synthesized by varying the degree of acetylation (DA) from ˜2 to ˜30 mol% and the degree of substitution (DS) from 5 to 25%.

Diethylaminoethyl- chitosan as an efficient carrier for siRNA delivery: Improving the condensation process and the nanoparticles properties.

Chitosan has been indicated as a promising carrier for the preparation of small interfering RNA (siRNA) delivery systems due to its remarkable properties. However, its weak interactions with siRNA molecules makes the condensation of siRNA molecules into nanoparticles difficult. In this work, a non-viral gene delivery system based on diethylaminoethyl chitosan (DEAE-CH) derivatives of varied Mw (25-230 kDa) having a low degree of substitution of 15% was investigated.

Insights on the antifungal activity of amphiphilic derivatives of diethylaminoethyl chitosan against Aspergillus flavus.

In this study, the antifungal activity of chitosan derivatives against A. flavus was studied to understand the contribution of the molecular mass (Mw) and of the hydrophobic and electrostatic forces to the inhibition of fungal growth. The interaction of amphiphilics ranging from 8 to 130 kDa with model membranes of zwitterionic L-α-phosphatidylcholine (PC) and anionic L-α-phosphatidylcholine/L-α-phosphatidyl-DL-glycerol (PC:PG, 80:20 mol%) were exploited to obtain information on the inhibition mechanism.

Biochemical Characterization, Thermal Stability, and Partial Sequence of a Novel Exo-Polygalacturonase from the Thermophilic Fungus A13.36 Obtained by Submerged Cultivation.

This work reports the production of an exo-polygalacturonase (exo-PG) by A13.36 in submerged cultivation (SmC) in a shaker at 45°C for 96 h. A single pectinase was found and purified in order to analyze its thermal stability, by salt precipitation and hydrophobic interaction chromatography.