Hollow Nanospheres Based on the Self-Assembly of Alginate-graft-poly(ethylene glycol) and α-Cyclodextrin

This article studies the self-assembly of alginate-graft-poly(ethylene glycol) (Alg-g-PEG) and alpha-cyclodextrin (alpha-CD) in aqueous solution. It was found that they could form hollow spheres because of the formation of coil-rod Alg-g-PEG/alpha-CD inclusion complexes. In these Alg-g-PEG/alpha-CD complexes, the alpha-CDs are stacked along the PEG side chains to form a rod block, and alginate main chains act as a coil block. More rod-like blocks in Alg-g-PEG/alpha-CD favor the formation of small assemblies. The assemblies of Alg-g-PEG/alpha-CD show a dependence on concentration, temperature, pH, and salt concentration. At low concentration (below 0.125%) or high temperature (above 32 degrees C), Alg-g-PEG/alpha-CD particles were unstable and disrupted. Increasing the salt or decreasing the pH resulted in the aggregation of Alg-g-mPEG/alpha-CD particles, as detected by the increase in the recorded hydrodynamic diameter (D-h).