Cloaking cytolytic peptides for liposome-based detection and potential drug delivery

Potent cytolytic peptides with specific tethering and cloaking sites have been synthesised and used to release payload from liposomes in a quantitative manner. A functionally located cloaking site has been modified specifically by simple conjugation without adversely affecting the cytolytic properties of the peptide. The cytolytic activity of modified peptides was then efficiently (> 98%) cloaked and uncloaked by ligand-protein or hapten-antibody interactions. The principle of a dual response peptide has been demonstrated using an avidin-cloaked pH-sensitive peptide. Biospecific cloaking/uncloaking provided a new sensitive (similar to 12 pmol) homogeneous diagnostic and also appears potentially suited to bioresponsively targeted release of antimicrobial, anticancer and other drugs now delivered using liposomes. (C) 2002 Elsevier Science B.V. All rights reserved.