Self-assembly of peptides into spherical nanoparticles for delivery of hydrophilic moieties to the cytosol

Abstract

We report a novel class of self-assembling peptide nanoparticles formed by mixing aqueous solutions of K16 peptide and a 20 amino acid peptide of net charge -5 (GLFEALLELLESLWELLLEA). Particle formation is salt-dependent and yields perfectly spherical nanoparticles of ∼ 120 to ∼ 800 nm diameter, depending on buffer composition and temperature, with a stoichiometry of ∼ 1:2.5 for the cationic and anionic peptides. The anionic peptide forms an α-helix in aqueous solution, has all five glutamates on one side of the helix, and exists entirely as a discrete oligomer of 9-10 peptides. A rigid oligomer with 45-50 negative charges almost certainly represents the core component of these nanoparticles..