A reduction-triggered delivery by a liposomal carrier possessing membrane-permeable ligands and a detachable coating

Takuro Maeda, Keiji Fujimoto

Research output: Contribution to journalArticle

60 Citations (Scopus)


To control the cellular uptake of drugs and genes, we synthesized a liposomal carrier possessing membrane-permeable ligands and a detachable poly(ethylene glycol) (PEG) coating. For the detachable coating, a lipid having a thiolytic cleavable spacer (PEG-S-S-DOPE) was synthesized by the reaction of dioleoylphosphatidylethanolamine (DOPE) with a PEG chain via a disulfide linkage. The liposomes were prepared from a mixture of dipalmitoylphosphatidylcholine (DPPC), DOPE, PEG-S-S-DOPE, and cholesteryl hemisuccinate (CHEMS). The octamer (R8 peptide) of arginine was chosen as the membrane-permeable ligand and covalently immobilized onto the CHEMS portion of the liposome surface (PEG-S-S-R8-liposome). The disulfide bond of the PEG chain was cleaved to display the R8 peptides on the liposome surface by adding a reducing agent such as l-cysteine, and thereby internalization of the liposomes was significantly facilitated. When l-cysteine was added to the mixture of cells and the liposome that incorporated plasmids encoding the enhanced green fluorescence protein (pEGFP), the expression of EGFP was low but could be observed in almost 100% of the cells.

Original languageEnglish
Pages (from-to)15-21
Number of pages7
JournalColloids and Surfaces B: Biointerfaces
Issue number1
Publication statusPublished - 2006 Apr 15



  • Gene delivery
  • Liposome
  • Membrane-permeable
  • PEG coating
  • Reductive trigger

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

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