2024 AIChE Annual Meeting
Exploring Liposome-Chitosan and Liposome-Xanthan Gum Interactions
My work focuses on studying the interactions between liposomes and two different polyelectrolytes (chitosan, a polycation, and xanthan gum, a polyanion). We are specifically interested in understanding liposome stability upon interaction with these polyelectrolytes. To assess liposome stability in the presence of the polyelectrolytes, I utilize dynamic light scattering (DLS), zeta-potential measurements, and a calcein leakage assay via fluorescence spectroscopy. When combining chitosan with a 0.25 mg/mL solution of liposomes, a substantial increase in measured effective diameter was observed from 1 ppm to 10 ppm chitosan. Alternatively, xanthan gum did not seem to change effective diameter over the same incorporation range. The calcein leakage assay provided additional confirmation for the interaction of liposomes and chitosan and lack thereof for liposomes and xanthan gum. I concluded that this is due to the tendency of the polar head group of a liposomes bilayer to bind more effectively to positive charges due to a negative zeta-potential being present around a bare liposome, which in this case allows for chitosan to bind more effectively than the xanthan gum. Additionally, calculation of the number of charged groups per mass of each polyelectrolyte shows that xanthan gum has 2.5 times more charge density than chitosan, further amplifying its charge repulsion with liposomes.