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

胶体分散体是一种悬浮在液体中的微观或纳米级颗粒，在我们的日常生活中无处不在，从食品到化妆品、油漆、油墨到药品。目前的研究计划侧重于阐明一种新型软的，可变形的胶体，植物糖原纳米颗粒的物理性质。这些颗粒是在我的实验室里发现的，是从甜玉米中分离提纯出来的。颗粒的高度分支，树状结构产生了特殊的性质，使它们在个人护理，营养和生物医学的广泛应用中具有理想的用途。为了充分利用这些应用，有必要详细了解粒子的复杂物理性质，我的研究小组正在领导这项工作。目前的建议侧重于理解粒子性质的三个不同方面：集中分散的软玻璃物理，粒子之间的相互作用，以及粒子与其他纳米粒子之间的相互作用。我们将通过研究我们用酸和酶水解修饰过的颗粒来做到这一点。这些修饰将去除天然颗粒外表面的毛状链，并可能修饰颗粒的内部，改变它们的玻璃动力学，以及颗粒之间和与其他纳米颗粒的相互作用。我们还将用疏水基团对粒子进行化学修饰，以实现粒子之间的吸引相互作用，我们将研究在这些相互作用的存在下形成的集中分散的精致凝胶状结构的分解，为疏水相互作用的本质增加新的见解。带电基团修饰粒子后，由于静电效应，粒子间的斥力相互作用增强。我们还将研究植物糖原纳米颗粒与金属纳米颗粒通过物理结合的相互作用，并将其与金属纳米颗粒与植物糖原纳米颗粒共价键的情况进行比较。为了完成这项工作，我们将使用广泛的最先进的样品制备，显微镜，光谱和散射技术。我们的研究结果将提高我们对这种新型可持续纳米材料复杂特性的理解，更广泛地说，为软胶体的热力学、结构和动力学之间的复杂关系提供新的见解。我们的工作也将有助于确定和优化这种绿色、可持续的纳米技术的新应用。研究生和本科生将接受独特的多学科培训，为他们在学术界、政府和工业界的各种职业生涯中做出高水平的贡献做好准备。

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.