Biominerals, Fibres, and Soft Materials at the Nanoscale

我的研究计划主要集中在纳米尺度的机械性能和工艺，并开发探索这一制度所需的工具。 例如，我的兴趣之一是结晶--一个在自然界和工业中都很重要的过程。 结晶的一个特别令人感兴趣的方面是某些分子“毒物”通过吸附到特定的晶体生长面来控制结晶动力学的能力。 这种所谓的动力学抑制剂在商业上是相关的（例如，防止柴油燃料在低温下的“凝胶化”和天然气管道中笼形水合物的形成），医学上（例如，预防人类的肾结石），以及在自然界中（例如，使某些生物在零度以下的温度下生存的蛋白质）。 另一个研究方向是在纳米尺度上测量材料的机械强度。 了解纳米材料的机械性能，以及这些性能如何从它们的结构中产生，是它们在技术中使用的先决条件。 这两个主题在我实验室使用的主要工具中相交：原子力显微镜（AFM）。 AFM的这种使用导致了几个合作项目。 一个仍处于早期阶段的例子是测量获得性牙釉质膜的粘附特性，牙釉质膜是一层薄的蛋白质层，保护牙齿免受蛀牙并控制牙菌斑的形成。在接下来的五年里，我们将使用原子力显微镜在分子水平上研究允许某些肽阻止肾结石钙化的机制。 在第二个合作项目中，我们将使用原子力显微镜直接测量特定口腔细菌对获得性牙釉质膜的粘附。 我们最近对蜘蛛螨丝（一种由常见植物害虫产生的天然纳米材料）的研究表明，需要开发新的理论技术来理解非常薄（<100 nm），高弹性纳米纤维的机械性能。 我也对软材料感兴趣，如聚乙烯醇水凝胶，它作为生物材料有一系列的应用，包括活性伤口敷料，人工软骨和血管移植物。 由于将这些材料定制到特定的应用需要了解它们的结构，我们采用了一套技术来研究它们，包括小角中子散射和微观流变学，我们现在将扩展到包括介电谱。参与我的研究计划的学生将学习先进的表征技术，发展强大的分析能力，并从多学科的研究环境中受益。 这将为他们提供所需的广泛背景，将他们的培训应用于与工业和医学有关的广泛问题，从而增加他们的职业机会。

My research program is focused on mechanical properties and processes at the nanometer scale, and developing the tools needed to explore this regime. For example, one of my interests is crystallization-a process of importance in both nature and industry. An especially interesting aspect of crystallization is the ability of certain molecular "poisons" to control crystallization kinetics by adsorbing to specific crystal growth faces. Such so-called kinetic inhibitors are relevant commercially (e.g., the prevention of "gelation" of diesel fuels at low temperature and of clathrate hydrate formation in natural gas pipelines), medically (e.g., the prevention of kidney stones in humans), and in nature (e.g., proteins that allow some organisms to survive subzero temperatures). Another research direction has been the measurement of the mechanical strength of materials on the nanometer scale. Understanding the mechanical properties of nanomaterials, and how these properties arise from their structure, is a prerequisite to their use in technology. These two themes intersect in the principal tool employed in my laboratory: the atomic force microscope (AFM). This use of the AFM has resulted in several collaborative projects. One example that is still in its early stages is the measurement of the adhesive properties of the acquired enamel pellicle, a thin protein layer that protects teeth from cavities and controls plaque formation.****Over the next five years, we will use the AFM to study-at the molecular scale-the mechanisms that allow certain peptides to prevent calcification responsible for kidney stones. In a second collaborative project we will use the AFM to directly measure the adhesion of specific oral bacteria to the acquired enamel pellicle. Our recent work on spider-mite silk, a natural nanomaterial produced by a common plant pest, indicated a need to develop new theoretical techniques to understand mechanical properties in the limit of very thin (<100 nm), highly elastic nanofibres. I am also interested in soft materials such as poly(vinyl alcohol) hydrogels, which have a range of applications as a biomaterial, including active wound dressings, artificial cartilage, and vascular grafts.  Since tailoring these materials to specific applications requires an understanding of their structure, we have employed a suite of techniques to study them, including small-angle neutron scattering and microrheology, which we will now extend to include dielectric spectroscopy.****Students involved in my research program will learn advanced characterization techniques, develop strong analytical skills, and benefit from a multidisciplinary research environment. This will provide them with the broad background needed to apply their training to a wide range of problems relevant to industry and medicine, thus enhancing their career opportunities.**