Amyloid β, Aβ(1–42), is a component of senile plaques present in the brain of Alzheimer’s disease patients and one of the main suspects responsible for pathological consequences of the disease. Herein, we directly visualize the Aβ activity toward a brain-like model membrane and demonstrate that this activity strongly depends on the Aβ oligomer size. PeakForce quantitative nanomechanical mapping mode of atomic force microscopy imaging revealed that the interaction of large-size (LS) Aβ oligomers, corresponding to high-molecular-weight Aβ oligomers, with the brain total lipid extract (BTLE) membrane resulted in accelerated Aβ fibrillogenesis on the membrane surface. Importantly, the fibrillogenesis did not affect integrity of the membrane. In contrast, small-size (SS) Aβ oligomers, corresponding to low-molecular-weight Aβ oligomers, created pores and then disintegrated the BTLE membrane. Both forms of the Aβ oligomers changed nanomechanical properties of the membrane by decreasing its Young’s modulus by ∼45%. Our results demonstrated that both forms of Aβ oligomers induce the neurotoxic effect on the brain cells but their action toward the membrane differs significantly.

Single‐atom catalysts (SACs) are highly enviable to exploit the utmost utilization of metallic catalysts; their efficiency by utilizing nearly all atoms to often exhibit high catalytic performances. To architect the isolated single atom on an ideal solid support with strong coordination has remained a crucial trial. Herein, graphene functionalized with nitrile groups (cyanographene) as an ideal support to immobilize isolated copper atoms G(CN)‐Cu with strong coordination is reported. The precisely designed mixed‐valence single atom copper (G(CN)‐Cu) catalysts deliver exceptional conversions for electrochemical methanol oxidation (MOR) and CO2 reduction (CO2RR) targeting a “closed carbon cycle.” An onset of MOR and CO2RR are obtained to be ≈0.4 V and ≈−0.7 versus Ag/AgCl, respectively, with single active sites located in an unsaturated coordination environment, it being the most active Cu sites for both studied reactions. Moreover, G(CN)‐Cu exhibited significantly lower resistivity and higher current density toward MOR and CO2RR than observed for reference catalysts.