Surface-mediated Peptide Self-assembly to Modulate Surface Energy

Event Details

Type

Center for Studies in Physics and Biology Seminars

Speaker(s)

Zahra Fakhraai, Ph.D., associate professor, University of Pennsylvania

Speaker bio(s)

Amyloid-forming peptides or proteins typically form amyloid fibrils through a nucleation and growth mechanism. The nucleation step typically requires a minimum concentration of peptides in the solution, thus preventing this one-dimensional crystallization process from moving forward in dilute solutions. Fakhraai and her team demonstrate that a dilute solution, where bulk nucleation and growth is limited, providing the right surface, can promote rapid self-assembly of peptides into mono-layer thick amyloid fibrils within minutes. This process is diffusion-limited and depends on the orientation and diffusion of peptides on the surface. The deposition rate of peptides, as well as their orientation and diffusion on the surface strongly depend on the strength of the peptide-surface interactions. The self-assembly can be suppressed either by reducing the interaction such that the deposition rate is reduced or by increasing the interaction energy to a point where the peptide diffusion is substantially reduced. Once the self-assembly moves forward with time, the side-chains of the residues can modulate the surface energy and thus the interaction energy between the incoming peptides and the effective surface. As such, depending on the nature of the side chains, the surface can become more hydrophobic or hydrophilic and promote or prevent the further deposition of the peptides. Fakhraai demonstrates the generality of using this method to modulate the effective surface energy by the desired amount through the design of side chains, thus engineering surfaces with self-limiting self-assemblies with specific surface energy values.

Open to

Public

Contact

Melanie Lee

Phone

(212) 327-8636

Sponsor

Melanie Lee
(212) 327-8636
leem@rockefeller.edu