A study on the interaction of nanoparticles with lipid membranes and their influence on membrane fluidity

In recent years, liposomes encapsulated with nanoparticles have found enormous scopes in various biomedical fields such as drug design, transport, imaging, targeted delivery and therapy. These applications require a clear understanding about the interaction of nanoparticles with cell membranes. The present work aims to investigate the effect of encapsulation of uncharged and positively charged nanoparticles in three different types of lipids such as1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC),1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine and1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(SOPC-POPS) mixture and archaeal lipids. Through the temperature dependent fluorescence anisotropy measurements, we have found that the entrapment of nanoparticles in the bilayer has decreased the lipid transition temperature and increased the membrane fluidity of all three types of lipid vesicles. The results were more predominant in SOPC-POPS mixture because of high density encapsulation of nanoparticles in the vesicles due to electrostatic interaction between negatively charged membrane and positively charged iron oxide nanoparticles.