Two/three-dimensional interfacial properties of the novel peptide as a selective destroyer of biomembrane

Peptides are widely used in biomedicine field for their good biocompatibility and variable secondary structures. In this study, a novel amphiphilic peptide (amPE) was designed for antimicrobial agent. Its thermal responsiveness in solution and in liposome membrane was studied by circular dichroism (CD). Then, amPE's adsorption and further insertion behaviors at lipid monolayer were investigated by Langmuir-Blodgett (LB) and polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS). Results showed that amPE could selectively insert into DPPG monolayer due to the electrostatic interaction and cause an increase in content of alpha-helix. Adsorption kinetics under different initial surface pressures showed higher surface pressure prevented peptide's insertion. Then, experiments of dye leakage from liposomes were carried for discussing how amPE disturbed the liposome membrane. Serious dye leakage from DPPG liposome was observed and the leakage was further improved when temperature increased from 37 degrees C to 45 degrees C. The designed amPE showed its good potential as antimicrobial/antitumor agent and great superiority of thermal responsiveness.