Understanding functional properties of biological and smart materials

核磁共振是一个强大的工具，用于了解负责功能特性的材料的纳米级特征。在生物组织中，了解成像对比度产生的机制对于临床应用成像方法至关重要。在新的工程材料类别中，了解光学，机械和电学特性的机制对于将这些新材料应用于现实世界的问题至关重要。该提案描述了两个领域的研究：生物组织和工程“智能”材料，统一的愿景是深入了解结构、功能和特性之间的关系，以实现应用。在脑组织中，隔离神经轴突的髓鞘在神经冲动的传递中起着关键作用。髓鞘的丰度和状态的非侵入性测量是一个巨大的挑战。令人惊讶的是，在一些广泛使用的磁共振成像（MRI）技术来测量髓鞘中产生对比度的机制知之甚少。我们的目标是：1）探索髓磷脂中核自旋系统的物理细节，2）使固态NMR技术的方法适应体内成像的约束，3）开发新的对比机制以更好地表征髓磷脂的丰度和健康，4）理解MRI脉冲序列对可观察到的NMR/MRI信号的间接影响，这些信号来自大脑中“不可见”的非水成分。在工程材料方面，我们将与几个不同的研究小组合作，以解释他们制造的材料的新特性，并指导其开发和应用。这些材料包括：i）一类新的热固性聚合物，其为具有可调性质的真正可再循环塑料提供了有希望的途径，ii）将用于双向人机界面的离子传导聚合物膜，以及iii）一类新的氢键键合液晶，其显示出独特的性质，例如光学开关和在大温度范围内稳定的备受追捧的“蓝相”。对于这些系统中的每一个，我们将结合联合收割机核磁共振测量与新的原位机械，电气或光学刺激，以揭示微观结构和过程负责其有用的性能。这些研究对于指导材料的开发及其应用至关重要。这项研究的影响将不仅体现在各个项目的领域内，创新的混合NMR方法将为分子机制提供无与伦比的新见解，而且还体现在结果的合成中;通过学习这些材料和组织的共同主题和独特差异，我们将扩大和加深我们的理解，使得材料的快速发展和用于医学成像的更好的对比度方法成为可能。

Nuclear magnetic resonance is a powerful tool for understanding the nanoscale features of materials that are responsible for functional properties. In biological tissues, understanding the mechanisms that give rise to imaging contrast is crucial for applying imaging methods clinically. In new classes of engineered materials, understanding the mechanisms of optical, mechanical, and electrical properties is essential for applying these new materials to real-world problems. This proposal describes research in two areas: biological tissues, and engineered `smart' materials, unified by the vision of developing deep understanding of the relationships between structure, function, and properties to enable applications. In brain tissue, the myelin sheath that insulates nerve axons plays a key role in the transmission of nerve impulses. Non-invasive measurement of the abundance and condition of the myelin is a grand challenge. Surprisingly, the mechanisms that give rise to contrast in some widely used magnetic resonance imaging (MRI) techniques to measure myelin are poorly understood. Our objectives are to: 1) explore the details of the physics of the nuclear spin systems in myelin, 2) adapt methodology from solid-state NMR techniques to the constraints of in vivo imaging, 3) develop new contrast mechanisms to better characterize myelin abundance and health, 4) understand the indirect effects that MRI pulse sequences have on the observable NMR/MRI signals, arising from the "invisible" non-aqueous components in brain. In engineered materials, we will work with several different research groups in order to explain the novel properties of the materials they make, and guide their development and application. These materials include: i) a new class of thermoset polymers that offer a promising path to truly recylable plastics with tunable properties, ii) ionic conducting polymer membranes that will be useful for bidirectional human-computer interfaces, and iii) a new class of hydrogen-bonded liquid crystals that show unique properties such as optical switching and a highly-sought after "blue-phase" that is stable over a large temperature range. For each of these systems, we will combine NMR measurements with novel in situ mechanical, electrical, or optical stimulation in order to reveal the microscopic structures and processes responsible for their useful properties. These studies are essential to guide the development of the materials and their applications. The impact of this research will be felt not only within the fields of the individual projects, where the innovative hybrid NMR methods will provide unparalleled new insights into molecular mechanisms, but also from the synthesis of the results; by learning from the common themes and unique differences of these materials and tissues, we will both broaden and deepen our understanding, enabling rapid advancement of materials and better contrast methods for medical imaging.