Stability enhancement efficiency of surface decoration on curcumin-loaded liposomes: Comparison of guar gum and its cationic counterpart

To improve phospholipid bilayer membrane stability and reduce degradation of encapsulated curcumin, liposomes coated with guar gum (GG) and cationic guar gum (CGG) were prepared, and the physical properties of both were evaluated. The zeta potential results suggested that electrostatic interaction existed between the CGG and the negatively charged liposomes. A core−shell structure was observed under transmission electron microscopy; moreover, dynamic light scattering, atomic force microscopy, and Fourier transform infrared spectroscopy analysis confirmed that both GG and CGG were successfully coated on the surface of the vesicles. Fluorescence and Raman spectra and X-ray diffraction analysis indicated that GG and CGG could decrease membrane fluidity and enhance the lateral packing of lipids, and the structure stabilization effect was greater for CGG than GG. Further stability evaluation demonstrated that the liposome coating, especially the CGG-surface modified coating, could protect curcumin from the damage caused by oxidation or heat. Thus, the results suggested that CGG deposited onto the surface of liposomes could stabilize the lipid bilayer structure and retain the encapsulated curcumin better than GG. CGG-decorated liposomes could be developed as a formulation for encapsulating and delivering functional ingredients.