Nucleation and Growth of Two-Dimensional Inclusion Complex Crystals of β-Cyclodextrin and a Triblock Copolymer: Implications for Nanocarriers

Nanocarriers have emerged as robust platforms for drug delivery and biomedical applications. Inclusion complex crystals formed between cyclodextrin (CyD) and polymers are supramolecular crystals with topologically constrained structures, and their self-assembled particles are promising candidates for a supramolecular nanocarrier because of the biocompatibility of the components. However, these inclusion complex crystals typically form disordered particles, making morphological studies and controls challenging. In this study, the inclusion complex 2D crystal between β-CyD and a poly(ethylene oxide)- b -poly(propylene oxide)- b -poly(ethylene oxide) triblock copolymer was used as a model system, which forms single-crystal 2D particles with well-defined morphologies and high dispersibility in solvent. The size of these single-crystal particles generated in the solvent was determined through a nucleation and growth mechanism. Furthermore, seed growth from small particles was demonstrated, resulting in a narrower size distribution. This study provides insights into their potential for the structural controllability of two-dimensional particles consisting of inclusion complexes of CyD and polymer, having potential for nanocarrier.