September 25th CTE Virtual Seminar

Title: Biomaterials Based on Self-Assembling Peptides for Drug Delivery, Ion-
Transport, and Sensing

Presenter: Dr. John B. Matson

Associate Professor
Department of Chemistry, Virginia Tech

Abstract: One focus of the Matson lab is on short amphiphilic peptides designed to self-assemble water into a variety of nanoscale morphologies, including spheres, cylinders, ribbons, sheets, and others. In many cases, these nanostructures can aggregate to form hydrogels, which we use in drug delivery and tissue engineering applications, specifically in cardiovascular disease and wound healing. We recently discovered a class of peptides that self-assemble into helical structures with a regular pitch of 30 nm.
These nanohelices, formed by tetrapeptides of the general structure KSXZKS (KS = lysine modified with an S-aroylthiooxime [SATO]; X and Z = variable amino acids) take on a left-handed helical conformation. The SATO unit included in these tetrapeptides is capable of releasing hydrogen sulfide (H2S), a vital biological signaling gas, in response to a cysteine trigger. Interestingly, the nanocoils release H2S more slowly than constitutionally isomeric tetrapeptides that form twisted nanoribbons, and this difference in release rate results in differential bioactivity in cell studies. Through coarse-grained molecular dynamics simulations, we discovered that these tetrapeptide nanocoils have closely spaced charged residues (typically glutamic acid), which we found through experiments enables efficient ion conduction in water. Finally, we used the same nanocoils to template formation of plasmonic silver nanoparticles, which showed high efficiency in surface-enhanced Raman scattering.