Screening Effect of PEG on Avidin Binding to Liposome Surface Receptors

Thomas Kaasgaard, Ole G. Mouritsen, Kent Jørgensen

Research output: Contribution to journalConference articleResearchpeer-review


This study investigates the screening effect of poly(ethylene glycol)-phospholipids (PE-PEG) on the interaction of avidin with PEGylated liposomes containing surface-bound biotin ligands. The influence of grafting density and lipopolymer chain length is examined. A simple fluorescence assay involving a receptor-mediated fluorescence increase of BODIPY-labeled avidin upon binding to biotinylated lipids is employed to study the screening effect of submicellar concentrations of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine-N-[poly(ethylene glycol)-2000] (PE-PEG(2000)) and 1.2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine N-[poly(ethylene glycol)-5000] (PE-PEG(5000)) incorporated into 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) liposomes. The results show that incorporation of lipopolymers into DPPC lipid bilayers reduces binding of avidin to the biotinylated liposomes. and it is found that the screening effect of PE-PEG(5000) is stronger than that for PE-PEG(2000). Thus, the results reveal that both the grafting density and the polymer length of the PE-PEC lipopolymers are of importance for the ability of water-soluble macromolecules to reach the surface of PEG liposomes. Furthermore. it is found that none of the lipopolymers completely prevents avidin from reaching the surface-bound biotin ligands.
Original languageEnglish
JournalInternational Journal of Pharmaceutics
Issue number1-2
Pages (from-to)63-65
Publication statusPublished - 2000
Event3rd European Workshop on Particulate Systems - Utrecht, Netherlands
Duration: 27 Apr 200029 Apr 2000
Conference number: 3


Conference3rd European Workshop on Particulate Systems


  • PEG liposomes
  • Steric stabilization
  • Receptor-ligand interaction
  • Lipopolymer
  • Drug targeting
  • Avidin
  • Biotin


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