Keywords: alpha–cyclodextrin, polysebacic acid, biodegradable PSA, inclusion complex, nanostructures, self–assembly, nanoparticles, nanotechnology
Structural formation of inclusion complex nanoparticles from α–cyclodextrin and polysebacic acid
Inclusion complexes (IC) of α–cyclodextrin (α–CD) and biodegradable polysebacic acid (PSA) are prepared by using two different conditions of pH values. Interestingly, IC prepared at neutral pH (pH 7) shows turbidity and then into white precipitate, while IC prepared at alkaline pH (pH 10) forms into a clear solution, indicating the pH dependent behaviour of the IC and its formation of supramolecular assembly varies significantly by changing the pH. Moreover, it is found that by changing the pH, the affinity of the guest molecules with the CD cavity differs from strong intermolecular hydrogen bonding to weakly electrostatic interaction between PSA and α–CD. All experimental results suggest that the PSA chains are included into the α–CD cavity and the nanostructure of IC possesses a channel structure. PSA self–assembled into nanostructures in alkaline solution upon the addition of α–CD. The nanostructures produced were vesicular in shape as observed by TEM and hydrodynamic radius (Rh) obtained from DLS was ca.128 nm.