Single-Molecule Atomic Force Microscopy Force Spectroscopy of Modified Phytoglycogen Nanoparticles

Phytoglycogen (PG) is a naturally occurring nanoparticle that is produced in sweet corn. It is composed of highly branched glucose chains that form a compact spherical particle with a dendrimer-like architecture [1]. PG’s composition and structure leads to highly ordered hydration water and its size and mechanical stiffness greatly depend on its hydration state [1]. These properties combined with its non-toxicity, deformability, stability in water, and ability to associate with bioactive molecules make PG an attractive nano-platform technology with applications in personal care, nutrition, and biomedicine. PG nanoparticles can be easily modified without the use of harsh chemicals. We have subjected PG to mechanical extrusion and enzymatic modifications to alter their morphology and deformability. We measured the modified nanoparticles using Atomic Force Microscopy (AFM) Force Spectroscopy to compare their size, structure and mechanical stiffness to that of native PG nanoparticles [2]. The large number of force-distance curves collected in AFM Force Spectroscopy provides high-resolution maps of the outer structure, inner structure, and mechanical modulus of single nanoparticles [1]. Our work shows the effectiveness of simple modifications in tuning the properties of PG nanoparticles and highlights PG as a novel, sustainable nanotechnology.

[1] Baylis, B. et al. Biomacromolecules 22(7), 2985-2995 (2021)

[2] Roman, L. et al. Carbohydrate Polymers 298, 120080 (2022)