Peptide-Mediated Membrane Transport of Macromolecular Cargo Driven by Membrane Asymmetry

Pep-1 is a cell-penetrating peptide that represents a powerful strategy for delivering large, hydrophilic therapeutic molecules into cells. Model membranes, such as lipid vesicles and planar bilayers, have been useful for investigating the direct translocation of cell-penetrating peptides. Here, we present a droplet interface bilayer-based approach to quantify pep-1-mediated β-galactosidase translocation. We found that β-galactosidase translocation is driven only by the negative transmembrane potential resulting from the asymmetric bilayers. The asymmetric droplet interface bilayer method may be generally applicable for high-throughput screening of the efficacy of cell-penetrating peptides.