Topography and Mechanical Properties of Phytoglycogen Nanoparticles

Phytogycogen is a naturally occurring glucose polymer that is produced in the form of highly-branched, compact nanoparticles by sweet corn. Phytoglycogen nanoparticles are a novel type of soft colloidal particle [1], and their deformability, unique hydration and safety makes them desirable for applications in personal care, nutrition and biomedicine. We have used atomic force microscopy (AFM) to measure the topography, deformability and effect of hydration of phytoglycogen nanoparticles. We have successfully immobilized the phytoglycogen nanoparticles on the terraces of annealed gold substrates by using a thiolated boronic acid-based self-assembled monolayer. To overcome the challenges of measuring these soft and deformable particles, we have used the Quantitative Imaging mode of our JPK AFM, which is an optimized mapping of many force-distance curves. This allows us to obtain detailed images of particle stiffness, particle-tip adhesion, and sample height for different applied forces, while minimizing the lateral forces exerted on the delicate particles. I will describe the detailed information – particle height, volume and mechanical properties – that we have measured for the phytoglycogen nanoparticles.

[1] H. Shamana et al., Soft Matter 14(31), 6496 – 6505 (2018).