Amyloid fibrils are insoluble protein aggregates comprised of highly ordered β-sheet structures and they are involved in the pathology of amyloidoses, such as Alzheimer's disease. A supramolecular strategy is presented for inhibiting amyloid fibrillation by using cucurbit[7]uril (CB[7]). CB[7] prevents the fibrillation of insulin and β-amyloid by capturing phenylalanine (Phe) residues, which are crucial to the hydrophobic interactions formed during amyloid fibrillation. These results suggest that the Phe-specific binding of CB[7] can modulate the intermolecular interaction of amyloid proteins and prevent the transition from monomeric to multimeric states. CB[7] thus has potential for the development of a therapeutic strategy for amyloidosis.

An investigation of the host–guest chemistry of cucurbit[n]uril (CB[n], n = 6 and 7) with α,ω-alkyldiammonium guests (H2N(CH2) x NH2, x = 4, 6, 8, 10, and 12) both in solution and in the gas phase elucidates their intrinsic host–guest properties and the contribution of solvent water. Isothermal titration calorimetry and nuclear magnetic resonance measurements indicate that all alkyldiammonium cations have inclusion interactions with CB[n] except for the CB[7]–tetramethylenediamine complex in aqueous solution. The electrospray ionization of mixtures of CB[n] and the alkyldiammonium guests reflects their solution phase binding constants. Low-energy collision-induced dissociations indicate that, after the transfer of the CB[n]–alkyldiammonium complex to the gas phase, its stability is no longer correlated with the binding properties in solution. Gas phase structures obtained from density functional theory calculations, which support the results from the ion mobility measurements, and molecular dynamics simulated structures in water provide a detailed understanding of the solvated complexes. In the gas phase, the binding properties of complexation mostly depend on the ion–dipole interactions. However, the ion–dipole integrity is strongly affected by hydrogen bonding with water molecules in the aqueous condition. Upon the inclusion of water molecules, the intrinsic characteristics of the host–guest binding are dominated by entropic-driven thermodynamics.

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