title: Morphology-Induced Defects Enhance Lipid Transfer Rates.
abstract: Molecular transfer between nanoparticles has been considered to have important implications regarding nanoparticle stability. Recently, the interparticle spontaneous lipid transfer rate constant for discoidal bicelles was found to be very different from spherical, unilamellar vesicles (ULVs). Here, we investigate the mechanism responsible for this discrepancy. Analysis of the data indicates that lipid transfer is entropically favorable, but enthalpically unfavorable with an activation energy that is independent of bicelle size and long- to short-chain lipid molar ratio. Moreover, molecular dynamics simulations reveal a lower lipid dissociation energy cost in the vicinity of interfaces ("defects") induced by the segregation of the long- and short-chain lipids in bicelles; these defects are not present in ULVs. Taken together, these results suggest that the enhanced lipid transfer observed in bicelles arises from interfacial defects as a result of the hydrophobic mismatch between the long- and short-chain lipid species. Finally, the observed lipid transfer rate is found to be independent of nanoparticle stability.
authors: Yan
authors: Y
authors: Xia
authors: Kamil
authors: K
authors: Charubin
authors: Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz , Graz 8010, Austria.|Department of Physics, Brock University , St. Catharines, Ontario L2S 3A1, Canada.
authors: Drew
authors: D
authors: Marquardt
authors: Frederick A
authors: FA
authors: Heberle
authors: John
authors: J
authors: Katsaras
authors: Jianhui
authors: J
authors: Tian
authors: Xiaolin
authors: X
authors: Cheng
authors: Ying
authors: Y
authors: Liu
authors: Mu-Ping
authors: MP
authors: Nieh