Polyanionic Cyclodextrin Induced Supramolecular Nanoparticle.

Ionizable cyclodextrins have attracted increasing attention in host-guest chemistry and pharmaceutical industry, mainly due to the introduction of favorable electrostatic interactions. The ionizable cyclodextrins could not only enhance its own solubility but also induce oppositely charged guests to form more stable complex. However, the aggregation induced by charged cyclodextrins has rarely been reported. In this work, guided by the concept of molecular-induced aggregation, a series of carboxyl modified cyclodextrins were synthesized via "click" and hydrolysis reaction. Then, UV-vis spectrum was used to investigate the aggregating behaviors induced by these cyclodextrins towards the cationic guest molecules. The results showed that only the hepta-carboxyl-β-cyclodextrin could induce the guest molecules to self-assemble into supramolecular spherical nanoparticles. Meanwhile, it could form stable inclusion complex with amantadine, a drug for anti-Parkinson and antiviral. The assembly behaviors were investigated by dynamic light scattering, scanning electron microscope, atomic force microscope, transmission electron microscope and NMR spectroscopy. The supramolecular nanoparticles induced by hepta-carboxyl-β-CD and its inclusion with amantadine could be used to encapsulate the model drug and achieve its controlled releasing behaviors.