Among the possible phase networks accessible by amyloid beta (Aβ), peptide nanotubes have generated considerable research interest because of their ability to self-assemble into robust nanostructures. The Aß peptide nanotube wall is four nm thick and consists of a peptide bilayer of β sheets, which is a configuration similar to the lipid bilayers observed in cell membranes. To strengthen the correlation between biomembranes and peptide nanotubes, current efforts are directed towards blocking the peptide nanotube termini with Aß-coated gold nanoparticles to design a nanocompartment that can accumulate substrates and segregate the internal environment from the surroundings, resulting in the development of peptide-derived protocells.<br/>Therefore, devising a method for directing Aß assembly to gold nanoparticle surfaces to form peptide nanotube-compatible capping agents was the primary goal of these studies. Circular dichroism and fourier transform infrared spectroscopy suggested that the kinetics of peptide self-assembly are greatly favored over conjugation of Aß to the gold nanoparticle surfaces. However, conjugation of Aß to the gold nanoparticles was observed in the most concentrated peptide solution that contained Aß congeners altered to have a glycine spacer, providing evidence that gold nanoparticle coating kinetics exhibits a concentration threshold and is sensitive to the length of the putative peptide.<br/>The formation of “peptide coronas” around the gold nanoparticles, visible via transmission electron microscopy, was used to confirm the successful coating of the gold nanoparticles. Electron microscopy was also used to evaluate the capping efficacy of the Aß-coated gold nanoparticles. Preliminary attempts at nanocompartment formation demonstrated that the affinity of Aß-coated gold nanoparticles for peptide nanotube termini is too low for a robust nanocapping event to occur passively. Future venues for optimizing these protocols involve maximizing the concentration of nanocapping agents or designing covalent cross-linking entities to actively guide the Aß-coated gold nanoparticles to the peptide nanotube termini.

Designing peptide-coated gold nanoparticles for the bottom-up assembly of amyloid nanocompartments

249th National Meeting (2015)

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