We investigated the formation kinetics of a single monolayer nanotube from bolaamphiphiles (consisting of a sugar residue, an alkyl chain, and an amino group) in solution. In this bolaamphiphile, a transition from a monomerically dispersed state to the nanotube takes place by changing the solvent condition. This transition was induced by fast mixing with a stopped-flow apparatus. From just after the mixing, this transition process was monitored in situ by time-resolved small-angle X-ray scattering. In this manner, we were able to derive the direct structural information as a function of time during the nanotube formation. The results revealed that disklike aggregates initially formed, which then grew and closed to produce a tubular structure.

Rationally designed bolaamphiphiles are known to self-assemble into nanotube structures. Herein, we report the formation of an inclusion complex between a nanotube and bovine serum albumin (BSA). This complex formation was confirmed by ultraviolet (UV) absorbance and electrophoretic light scattering (ELS). The structure for different mixing ratios of BSA to the nanotube was also investigated by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The structural analysis with our proposed model has revealed that the BSA molecules were contained within the internal space of the nanotube with maintenance of its tubular structure.