Nanoscience and Molecular Nanotechnology

Biography

Biography: Natalia Marchesan Bexiga

Abstract

Chitosan derivatives are often employed in drug delivery due to their biocompatibility, biodegradability and mucoadhesive properties. Carboxymethyl-chitosan nanoparticles (CMCNPs) can deliver drugs and other biomolecules in a controlled manner, using different administration routes. The aim of this study was to produce and characterize CMCSNPs loaded with ovalbumin (OVA-CMCNPs); the best formulation will be further used as model antigen in oral immunization. Carboxymethyl-chitosan was successfully obtained by reacting the pre-alkalized chitosan with monochloroacetic acid in aqueous solution under mechanical stirring. The occurrence of 6-O-carboxymethylation was evidenced by 1H NMR and the degree of substitution was found to be 0.77. OVA-CMCNPs were prepared by ionotropic gelation method with calcium chloride (CaCl₂) and OVA loading. NPs were evaluated by atomic force microscopy (AFM), dynamic light scattering (DLS) and fluorescence spectroscopy (FS) to determine total protein content (encapsulation efficiency). The mean hydrodynamic diameter (MHD) obtained for OVA-CSNPS was 205±2 nm, with polydispersity index of 0.10±0.03. The ζ-potential reached -12.4±1.5 mV and the count rate (kcps) found was 352±1.9. The mean particle diameter obtained from the atomic force microscopy (AFM) data for OVA-CSNPS was 225±3 nm. AFM image showed that CSNPs showed pseudo-spherical shape, but not OVA-CSNPs. OVA loading of 132 µg/ml resulted in encapsulation efficiency of 24.1% due to its isoelectric point (pI: 4.54). The results showed that the tested methods for size characterization are complementary and recommended in combination. The final formulation presented an excellent particle size range, good encapsulation efficiency, a larger quantity of nanoparticles and a ζ potential that indicates a stable colloid for long term storage