Exchange of monooleoylphosphatidylcholine as monomer and micelle with membranes containing poly(ethylene glycol)-lipid.
AUTOR(ES)
Needham, D
RESUMO
Surface-grafted polymers, such as poly(ethylene glycol) (PEG), provide an effective steric barrier against surface-surface and surface-macromolecule interactions. In the present work, we have studied the exchange of monooleoylphosphatidylcholine (MOPC) with vesicle membranes containing 750 mol wt surface-grafted PEG (incorporated as PEG-lipid) from 0 to 20 mol % and have analyzed the experimental results in terms of thermodynamic and stationary equilibrium models. Micropipette manipulation was used to expose a single lipid vesicle to a flow of MOPC solution (0.025 microM to 500 microM). MOPC uptake was measured by a direct measure of the vesicle area change. The presence of PEG(750) lipid in the vesicle membrane inhibited the partitioning of MOPC micelles (and to some extent microaggregates) into the membrane, while even up to 20 mol % PEG-lipid, it did not affect the exchange of MOPC monomers both into and out of the membrane. The experimental data and theoretical models show that grafted PEG acts as a very effective molecular scale "filter" and prevents micelle-membrane contact, substantially decreasing the apparent rate and amount of MOPC taken up by the membrane, thereby stabilizing the membrane in a solution of MOPC that would otherwise dissolve it.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1181164Documentos Relacionados
- Interfacial thickness of liposomes containing poly(ethylene glycol)-cholesterol from electrophoresis.
- The different faces of poly(ethylene glycol)
- Poly(ethylene glycol) or Poly(ethylene oxide)?: Magnitude of end-group Contribution to the Partitioning of Ethylene Oxide Oligomers and Polymers between Water and Organic Phases
- Effects of lipid headgroup and packing stress on poly(ethylene glycol)-induced phospholipid vesicle aggregation and fusion.
- Synthesis and MALDI-ToF characterization of dendronized poly(ethylene glycol)s