Tunable Hydration Properties of Charge Modified Phytoglycogen Nanoparticles

Phytoglycogen (PG) is a natural and sustainable nanoparticle with unique physical properties that make it ideal for applications in personal care, nutrition, and biomedicine. To tailor the physical and chemical properties of PG to specific functions, the particles can be chemically modified. The covalent attachment of charged groups provides a means of tuning the properties of PG through the introduction of electrostatic interactions. We have investigated the effects of charge modification on the hydration properties of PG that is anionically modified by carboxymethylation (CM-PG). The addition of monovalent (Na⁺) and divalent (Ca²⁺) ions through counterion exchange was found to result in dramatic differences in the swelling and network water structuring in CM-PG thin films, as measured using ellipsometry and attenuated total reflectance infrared (ATR-IR) spectroscopy. These studies demonstrate how charge modification of PG nanoparticles can be used to tune their properties for enhanced applications.