Confocal Laser Scanning Microscopy and Model Membranes to Study Translocation Mechanisms of Membrane Active Peptides

Abstract

Membrane active peptides hold great potential for targeted drug delivery systems and understanding their mechanism of uptake is a key step in the development of peptide based therapeutics and clinical use. Giant unilamellar vesicles are cell-sized model membranes that can be individually observed under the microscope. The lipid composition of these membranes can be controlled, and interaction with peptides and changes induced by the peptides can be directly followed. Relevant information on the specific steps of peptides uptake can be obtained using membranes of different lipid composition. The present work provides a selection of dynamics and kinetics of peptides at interaction with model membranes of different lipid composition. The systematic peptide-membrane interaction was investigated by laser scanning confocal microscopy. The peptides used in this study neither internalized nor induced pore formation in neutral membranes composed of phosphatidylcholine and cholesterol. In membranes with anionic phosphatidylserine or cone-shaped phosphatidylethanolamine, all peptides internalized but only two of them were able to form pores, showing that the length of the peptide, the numbers of the arginine amino acid or the length of the α–helix are also relevant for the penetration efficiency of peptides.

Integrin Facilitates the Internalization of TAT Peptide Conjugated to RGD Motif in Model Lipid Membranes

“…We previously demonstrated that interaction of peptides with membranes and their translocation efficiency depend on lipid composition [32,33,34] . The lipid head group charge and lipid topology are the main driving factors for the interaction and permeability of TAT peptides.…”

“…We previously demonstrated that interaction of peptides with membranes and their translocation efficiency depend on lipid composition. [32,33,34] The lipid head group charge and lipid topology are the main driving factors for the interaction and permeability of TAT peptides. Also, we have established that the hydrophobic lipid tails, either saturated or unsaturated (with cis-double bonds) do not influence the activity of the peptides.…”

Lipid-Based Nanotechnology: Liposome

“…Among these techniques, two commonly utilized methods include laser scanning confocal fluorescence microscopy (LSCFM) and total internal reflection fluorescence microscopy (TIRFM). LSCFM, known for its high resolution, optical sectioning, and 3D imaging capabilities [ 79 , 80 ], serves to characterize liposomes and observe their structure, behavior, and interactions with high precision [ 81 , 82 ]. In contrast, TIRFM is well-known for its accessibility and high sensitivity in probing biomolecules properties [ 83 ].…”