Structure, dynamics and mechanical properties of phytoglycogen nanoparticles: new insights into a novel sustainable nanomaterial

点击翻译按钮获取中文摘要

Colloidal dispersions, in which microscopic or nanoscopic particles are suspended in a liquid, are ubiquitous in our everyday lives, ranging from foods to cosmetics to paints and inks to pharmaceuticals. The present research proposal focuses on elucidating the physical properties of a novel type of soft, deformable colloid, phytoglycogen nanoparticles. These particles were discovered in my laboratory and are isolated and purified from sweet corn. The highly-branched, tree-like structure of the particles gives rise to special properties that make them desirable for use in a wide range of applications in personal care, nutrition and biomedicine. To fully exploit these applications, it is necessary to understand in detail the complex physical properties of the particles, and my research group is leading the effort to do this. The present proposal focuses on understanding three different aspects of the particle properties: the soft glassy physics of concentrated dispersions, interactions between the particles, and interactions between the particles and other nanoparticles. We will do this by studying particles that we have modified using acid and enzymatic hydrolysis. These modifications will remove the hairy chains on the outer surface of the native particles and possibly modify the interior of the particles, changing their glassy dynamics, and the interactions between particles and with other nanoparticles. We will also chemically modify the particles with hydrophobic groups to achieve attractive interactions between the particles, and we will study the breakdown of the delicate gel-like structures that form in concentrated dispersions in the presence of these interactions, adding new insight into the nature of hydrophobic interactions. Modification of the particles with charged groups will enhance the repulsive interactions between the particles because of electrostatic effects. We will also study the interaction of phytoglycogen nanoparticles with metallic nanoparticles through physical association and compare this to the case in which the metallic nanoparticles are covalent bonded to the phytoglycogen nanoparticles. To accomplish this work, we will use a wide range of state-of-the-art sample preparation, microscopies, spectroscopies and scattering techniques. Our results will improve our understanding of the complex properties of this novel sustainable nanomaterial and, more generally, provide new insights into the complex relationship between thermodynamics, structure and dynamics of soft colloids. Our work will also help to identify and optimize new applications of this green, sustainable nanotechnology. Graduate and undergraduate students will receive unique, multidisciplinary training that will prepare them to contribute at a very high level for a variety of careers in academia, government and industry.