Nanoscale chemical imaging: Tools and techniques for localised infrared spectroscopy of nanostructured polymers and biomaterials.

所有的生物本质上都是通过纳米级的自我组装形成的。化学相互作用控制着单个分子的物理顺序，将它们结合起来构建有序的结构，形成宏观生物体的基础。因此，所形成的整体结构可以被视为来自分子水平的化学编程。虽然这些过程在自然界中已经发生了数十亿年，但科学最近开始迎头赶上。对人工自组装材料的研究，无论是完全合成的还是生物启发的，都是纳米科学更广泛领域内一个非常活跃的研究领域。这些材料被广泛认为是一系列未来技术的关键。与此同时，纳米尺度结构的限制性尺寸往往导致化学过程以与大块材料中的化学过程明显不同的方式进行，从而提供了一种控制方法，例如，一些疾病的潜在分子原因。研究这种纳米尺度的结构，也许只有几十个原子的直径，对科学仪器提出了新的挑战。普通的显微镜根本无法看到如此小的结构，因为光的波长是这些尺寸的许多倍。虽然电子显微镜被广泛使用，但最近开发的技术是原子力显微镜（AFM）。原子力显微镜使用精细的探针，在某些情况下具有直径仅为几个原子的尖端，以建立样品的机械轮廓图像。AFM实际上是感觉而不是看到表面。小的探针针尖尺寸使AFM能够轻松地解析纳米尺度的特征，并且它们已经迅速成为该领域中无处不在的研究工具。然而，放弃光学显微镜有一个主要缺点。通过吸收或发射光来检测特定化合物的光谱学是AFM无法实现的。许多参与纳米级自组装的分子在红外线上具有特征性的光谱指纹。因此，联合收割机将红外光谱技术与原子力显微镜的纳米级成像能力结合起来，将具有巨大的价值。这些技术将为研究人员提供重要的新见解，了解单个纳米结构中的化学过程，从而使该领域取得重大进展。该项目的目标是精确地开发这样一种仪器。由于缺乏合适的红外激光器，无法精确地将其波长调谐到足以收集化合物的光谱指纹，因此早期的工作受到限制。在这个项目中，将开发基于所谓的非线性光学技术的新型类激光源，该技术有效地将激光器的输出从具有所需调谐特性的波长转移到不具有所需调谐特性的红外波长。第一个是对某些蛋白质的自然自组装进行纳米级控制，这些蛋白质被认为与阿尔茨海默病的进展有关。第二部分将研究设计师蛋白质自组装过程中发生的化学变化，这些变化可能构成人工组织的基础。最后，将研究形成功能表面的结构的行为，这些结构响应于局部化学环境而改变其物理性质。在所有情况下，以及测试项目中开发的新分析技术，预计将获得通过其他方法无法获得的新见解，进入正在研究的系统。

All living things are, in essence, formed by nanoscale self-assembly. Chemical interactions control the physical ordering of individual molecules, combining them to build ordered structures that form the basis of macroscopic organisms. The overall structures formed can, therefore, be seen as arising from molecular-level chemical programming . Although these processes have been occurring in nature for billions of years, science has recently started to catch up. The investigation of artificial self-assembled materials, both wholly synthetic and biologically inspired, is an extremely active area of research within the wider field of nanoscience. Such materials are widely recognised as key to a range of future technologies. At the same time, the restrictive dimensions of nanoscale structures often cause chemical processes in to proceed in a markedly different manner to those in bulk materials, thus offering a way to control, for example, the underlying molecular causes of some diseases.Studying structures of such nanoscale dimensions, perhaps only a few tens of atoms in diameter, presents new challenges for scientific instrumentation. Ordinary microscopes are fundamentally incapable of seeing such small structures due to the wavelength of light being many times these dimensions. While electron microscopes are widely used, a more recently developed technique is the atomic force microscope (AFM). An AFM uses a fine probe, in some cases having a tip only a few atoms in diameter, to build a mechanically profiled image of a sample. Effectively the AFM feels rather than sees the surface. The small probe tip dimensions allow AFMs to easily resolve nanoscale features, and they have rapidly become ubiquitous research tools in the field.However, abandoning the light microscope has a major disadvantage. Optical spectroscopy, detecting particular chemical compounds by their absorption or emission of light, is not possible with an AFM. Many molecules involved in nanoscale self assembly have characteristic spectroscopic fingerprints in the infrared. It would, therefore, be of immense value to combine the techniques of infrared spectroscopy with the nanoscale imaging capabilities of the AFM. Such techniques would give researchers important new insights into the chemical processes at work in individual nanostructures, allowing significant advances in the field. It is the aim of this project to develop precisely such an instrument.Promising early work to achieve this is limited by the lack of suitable infrared lasers able to precisely tune their wavelength far enough to collect the spectroscopic fingerprint of chemical compounds. In this project, novel laser-like sources will be developed, based on so-called nonlinear optical techniques, which effectively shift the output of a laser from wavelengths where the desired tuning properties are available to infrared wavelengths, where they are not.To test the techniques developed, several nanoscale chemical processes will be studied. The first is nanoscale control of the natural self-assembly of certain proteins thought to be associated with the progress of Alzheimer's disease. The second will examine chemical changes occurring during self-assembly of designer proteins, which may form the foundation of artificial tissues. Finally, the behaviour of structures forming functional surfaces that change their physical properties in response to the local chemical environment will be investigated. In all cases, as well as testing the new analytical techniques developed in the project, it is anticipated that new insights, unobtainable by other methods, will be gained into the systems under study.