Poster Presenter

Biophysical Studies on Chitosan
Mirhane Mostafa Darwish, Mohsen M. Mady, Mirhane M. Darwish, Safaa Khalil, Wafaa M. Khalil

Liposomes have been used as delivery vehicles for stabilizing drugs, overcoming barriers to cellular and tissue uptake, and for directing their contents toward specific sites in vivo. Chitosan is biological macromolecule derived from crustacean shells and has several emerging applications in drug development, obesity control and tissue engineering. In the present work, the interaction between chitosan and dipalmitoyl phosphatidylcholine (DPPC) liposomes was studied by transmission electron microscopy (TEM), zeta potential, solubilization using a nonionic detergent, octylglucoside (OG), as well as Fourier transform infrared (FTIR) spectroscopy and viscosity measurements. The coating of DPPC liposomes by a chitosan layer was confirmed by electron microscope images and the zeta potential of liposomes. Coating of liposome by chitosan resulted in increase of liposomal size by a layer of (92 ± 27.1 nm). The liposomal zeta potential is increasingly positive as chitosan concentration is increased from 0.1% to 0.3% w/v, then it came to a relatively constant value. The amount of detergent needed to completely solubilize the liposomal membrane was increased after coating of liposomes with chitosan, indicating an increased membrane resistance to the detergent and hence a change in the natural membrane permeation properties. In the analysis of FTIR spectra of DPPC, the symmetric and antisymmetric CH2 (at 2800-3000 cm-1) bands and the C=O (at 1740 cm-1) stretching band were investigated in the absence and presence of the chitosan. It was concluded that appropriate combining of the liposomal and chitosan characteristics might be utilised for the improvement of the therapeutic efficacy of liposomes as drug delivery system.