Constrained and UV-activatable cell-penetrating peptides for intracellular delivery of liposomes

Herein we report on the development of a novel method of constraining a cell-penetrating peptide, which can be used to trigger transport of liposomes into cells upon in this case radiation with UV-light. A cell-penetrating peptide, which was modified on both termini with an alkyl chain, was anchored to the liposomal surface in a constrained and deactivated form. Since one of the two alkyl chains was connected to the peptide via a UV-cleavable linker, disconnection of this alkyl chain upon irradiation led to the exposure of the cell-penetrating peptide, and mediated the transport of the entire liposome particle into cells.