Acetylenic Bond Layout Drives the Directional Assembly of Amyloid-like Peptides on Graphyne: Implications for Biomedical Safety Applications of Graphyne

Graphyne, a newly discovered carbon nanomaterial, has received increasing attention as a potential biomedical material. Although β-rich peptide scaffolds have been implicated in a range of neurodegenerative diseases, the mechanisms by which toxic peptides assemble and mediate neuropathic effects remain poorly understood. Modeling the interaction between graphyne and β-rich peptide scaffolds is crucial for understanding nanobiological effects or potential nanotoxicity and the safe design of graphyne as a nanomedicine material. Herein, we investigate the potential effects of graphyne on the assembly of Aβ33–42 peptides by molecular dynamics (MD) simulations. The Aβ33–42 peptide is considered to be the primary assembling core in the natural abnormal assembly of amyloid β (Aβ) proteins. The results show that Aβ33–42 strands are easily adsorbed to the graphyne surface and spontaneously aggregate into a well-structured β-chain-like monolayer assembly through chain straightening, nucleation, and assembly processes in turn. The sp1 and sp2 hybrid orbitals in the carbon electronic structure of graphyne dominate the alignment of Aβ33–42 strands along the C≡C bonds with a specific "armchair" direction. Our findings deepen the understanding of the interaction between graphyne and biological macromolecules and provide implications for biomedical applications of graphyne.