Abstract

SOTO-CRUZ, Jackeline et al. Structural Characterization of Chitosan Modified Vesicles. Uniciencia [online]. 2018, vol.32, n.1, pp.32-45. ISSN 2215-3470.  http://dx.doi.org/10.15359/ru.32-1.3.

L-α-phosphatidylcholine (PC) and PC/phosphoglycerol based-vesicles were characterized by Dynamic Light Scattering (DLS), Cryo-Scanning Electron Microscopy (Cryo-SEM), and Isotermal Titration calorimetry (ITC). The incorporation of phosphoglycerol into the PC vesicles decreased the size and the polydispersity of the particles, due to an increase of the packing of the aliphatic chains in the layer. This phenomenon has been interpreted in terms of strong van der Waals interactions. The addition of phosphoglycerols resulted in a reduction in zeta potential (ξ) to values of -75 mV, compared to PC based-vesicles. Both systems were modified by using a high molecular weight chitosan (865 kDa) with a degree of deacetylation of 77%. Strong electrostatic interactions between the cationic polyelectrolyte and the vesicles were determined by ITC experiments. The results were reinforced by means of Z potential analysis. It has been demonstrated that a complete inverse of the vesicle surface charge is not required to perform a complete coating of the phospholipid particles. The addition of concentration of chitosan above 0,1 mg/mL induced vesicles aggregation. Aggregated vesicle-polymer structures were visualized by Cryo-SEM and measured by DLS. This behavior was more significant for the PC/DMPG-Na-/chitosan system.

Keywords : vesicles; chitosomes; phospholipids; polyelectrolytes; surface modification.

        · abstract in Spanish | Portuguese     · text in Spanish     · Spanish ( pdf )