Interaction between phospholipids bilayer and chitosan in liposomes investigated by P-31 NMR spectroscopy

The interaction between chitosan and the polar head of phosphandylchohne (PC) is discussed for a composite nanovestcle obtained by incorporating chitosan in the organic phase before PC self-assembling Nanovesicles free of chitosan are studied in parallel to allow the compal ison concerning modifications produced on the composite system Zeta Potential increases in the presence of chnosan and with the increase in its concentration proving the localization of the polymer over the external surface of the vesicle as one interaction site A P-31 resonance around 0 ppm, characteristic of the system, is reduced with addition of chnosan at 25 degrees C. indicating motional fieedom reduction of the polar head phosphate group The same resonance signal remains almost constant after increasing the temperature to 60 degrees C, suggesting that chnosan shields the phospholipids polar heads as a consequence of the electrostatic interactions leading to an increase in the thermodynamic stability of the composite (C) 2009 Elsevier B V All rights reserved.