Effect of Lipid with Covalently Attached Poly(ethylene glycol) on the Surface Properties of Liposomal Bilayer Membranes

Abstract

The effect of lipid with covalently attached poly(ethylene glycol) (PEG−lipid) on the surface properties of liposomal bilayer membranes was examined from standpoints of particle size, surface potential, microviscosity, micropolarity, and permeability. The particle size and the absolute value of the ζ potential of liposomes decreased with increasing mole fraction of PEG−lipid. The permeability of PEG−liposomes was decreased as compared with regular liposomes. The microviscosity and the micropolarity of liposomal bilayer membranes showed a maximum and a minimum value, respectively, at 6 mol % of PEG−lipid. The packing state of liposomal bilayer membranes became rigid and the lipid bilayers were microscopically stabilized by the addition of PEG−lipid, and the optimum amount of PEG−lipid in liposomes was 6 mol %.

PEGylated lipids impede the lateral diffusion of adsorbed proteins at the surface of (magneto)liposomes

“…A high colloidal stability of the suspensions was further imparted by selecting anionic phospholipids (DMPG and DSPE-PEG) so that strong interparticle electrostatic repulsions were generated. The somewhat lowerpotential values observed for the PEGylated lipid structures, which are in agreement with the data of Piperoudi et al [15] and Yoshida et al [16], can be rationalized by assuming that the slipping plane at the PEG-aqueous layer interface is moved further from the vesicle or ML surface.…”

Characterization of phosphatidylcholine/polyethylene glycol‐lipid aggregates and their use as coatings and carriers in capillary electrophoresis

“…The higher the molar mass of PEG (i.e., the longer the PEG chain), the lower was the surface charge of the vesicles. This can be explained in terms of shielding of the negatively charged vesicle surface by the exposed PEG chains, which decreased the zeta potential of the vesicle [29,30]. However, the zeta potential of the POPC/DMPEG3000 aggregates was about 213 mV, which shows that the shorter C14 chains of the DMPEG-lipid clearly affect the packing of the lipids in the liposome.…”

Amitriptyline overdose treatment by pegylated anionic liposomes

“…1 [19]. Extrusion, a more recently developed method of forming lipid vesicles, has become a widely accepted technique due to the ability to control vesicle size [19,20]. …”

“…Additionally, they performed Monte-Carlo simulations which suggested that a large portion of the liposome surface was uncovered by PEG-2000 polymers at 2-10% addition of PEG modified lipid (molar basis). Yoshida et al also conducted simulations to estimate surface coverage and concluded that approximately 45% of the surface would be covered at 5% addition of PEG-2000 [20]. As far as the conformation of the PEG chains is concerned, Moghimi and Szebeni suggest that at very low coverages (below 5%), the polymers exhibit a mushroom-like behavior with a lack of extension into the aqueous bulk phase [27].…”