Hairy Particle Morphology of Dendritic Phytoglycogen Nanoparticles Revealed by Hydrophobic Modification

Phytoglycogen is produced by sweet corn as soft, compact nanoparticles with a dendritic or tree-like architecture. Its softness, porosity and mechanical integrity, together with its biodegradability and non-toxicity, make it a unique additive for formulations in personal care and biomedicine. We used small angle neutron scattering (SANS) of dilute dispersions of native phytoglycogen nanoparticles in mixtures of D₂O and H₂O to reveal the presence of hairy chains on the surface of the particles. However, these results did not uniquely determine the length and packing density of the hairy chains. To determine this, we used SANS to study phytoglycogen nanoparticles hydrophobically modified with octenyl succinic anhydride (OSA). We observed an additional scattering peak due to the collapse of the hydrophobically modified chains to form well-defined “seeds” on the surface of the particles, consistent with a “raspberry” particle geometry. These measurements allowed us to estimate the average hairy chain length to be 20 anhydroglucose units (AGUs).<sup>1

1</sup>J. Simmons et al., Biomacromolecules 2020, 21, 4053.