Interaction Forces between Supported Lipid Bilayers in the Presence of PEGylated Polymers

Abstract

Using the surface forces apparatus (SFA), interaction forces between supported lipid bilayers were measured in the presence of polyethylene glycol and two other commercially available pegylated triblock polymers, Pluronic F68 and F127. Pluronic F68 has a smaller central hydrophobic block compared to F127 and therefore is more hydrophilic. The study aimed to unravel the effects of polymer architecture and composition on the interactions between the bilayers. Our keys findings show that below the critical aggregation concentration (CAC) of the polymers, a soft, weakly anchored, polymer layer is formed on the surface of the bilayers. The anchoring strength of this physisorbed layer was found to increase significantly with the size of the hydrophobic block of the polymer, and was strongest for the more hydrophobic polymer, F127. Above the CAC, a dense polymer layer, exhibiting gel-like properties, was found to rapidly grow on the bilayers even after mechanical disruption. The cohesive interaction maintaining the gel layer structure was found to be stronger for F127, and was also found to promote the formation of highly structured aggregates on the bilayers.

Surface Plasmon Resonance Study of the Binding of PEO–PPO–PEO Triblock Copolymer and PEO Homopolymer to Supported Lipid Bilayers

“…One difference between the microcantilever and SPR instruments is that the microcantilever surface can bend upon molecule binding on the surface, which might provide more space between the lipid on the surface, resulting in more polymer binding on the surface. PEO did not adhere on the lipid membrane when probed by QCM 25 and surface force apparatus 21–24 . Polymer was injected for 10 min in the QCM experiment in contrast to our SPR experiment, in which the polymer injection was for 45 min.…”

Multimodal Miniature Surface Forces Apparatus (μSFA) for Interfacial Science Measurements

“…Only minor changes in the lipid/protein composition or the presence of very small quantities of additives such as polymers or nanoparticles can dramatically change membrane domain morphologies, with correspondingly dramatic influences on adhesion and other interactions between membranes. [12][13][14] Measuring and understanding the influences of such subtle effects often requires combined techniques applied under in situ conditions, providing motivation for the development of new combined instruments.…”

Effect of pluronic block polymers and N-acetylcysteine culture media additives on growth rate and fatty acid composition of six marine microalgae species

“…Enhanced microalgae growth in the presence of F127 relative to F68 medium additives in the present study is consistent with these observations. Pluronic F127 is a larger molecule (factor of 50 in size) with a larger hydrophobic block, relative to pluronic F68, and thus a more potent culture medium additive to protect cultured cells from shear-stress-induced damage (Banquy et al 2016).…”