Structural Role of Guest Molecules in Rapid and Sensitive Supramolecular Assembling System Based on β-Cyclodextrin-Conjugated Poly(ε-lysine)

Supramolecular assembling systems governed by intermolecular cooperative host−guest complexation and ionic interactions were investigated based on β-cyclodextrin-conjugated poly(ε-lysine) as a supramolecular host and several hydrophobic guest moieties. The geometric conformations for the inclusion complexation were characterized by 2D-ROESY NMR, and the pH- and thermoreversible properties were investigated by UV−vis measurements. In addition, systematic kinetics and thermodynamics of the supramolecular formation were studied by stopped-flow spectrophotometry and isothermal titration calorimetry, respectively. The trajectories of the binding site, the penetration depth of the guest moiety inside the β-cyclodextrin, ionic function groups, and other geometrical features gave detailed information on the rapidly stimuli-responsive supramolecular assembly formation.