Effect of the surface curvature on amyloid-β peptide adsorption for graphene

The adsorption of amyloid-β peptide (Aβ) onto graphene nanosheets with curvature at a neutral pH has been studied by using molecular dynamics simulations in combination with umbrella sampling. We found that Aβ adsorbed onto graphene with distinct characteristics, causing the breakage of hydrogen bonds which leads to its conformational change. Interestingly, the adsorption capacity of graphene's surface varies significantly depending on its curvature, namely, the surface with negative curvature has a higher probability to adsorb the Aβ than the one with positive curvature. This phenomenon is further evidenced by the binding energy between the complex of graphene and Aβ derived from the potential of mean force (PMF). The hydrophobic interactions and the direct dispersion interactions between the graphene nanosheet and the Aβ play a dominant role in the adsorption process. These findings indicate that not only is the chemical composition an important factor but also the shape of the nanoparticle is important in determining its interaction with proteins: the contacting surface curvature can lead to different adsorption capability.