Near-Field IR Microscope For Nanoscale Chemical Imaging

描述（由申请人提供）：该项目的目标是开发一种扫描探针显微镜的附件，以实现高通量，无孔径，近场红外显微镜（ANSIM）。该仪器的开发将使需要表征表面上复杂生物材料极小区域的传感应用成为可能。所提出的近场仪器将能够在小于100nm的横向空间分辨率下进行红外吸收光谱。ANSIM附件将被设计成小而便携，因此该附件的复制品可能成为其他原子力显微镜（afm）的实用附件。仪器开发计划有三个主要要素。首先，将红外量子级联激光阵列与引导红外激光进入和离开显微镜的光学元件组装在一起。其次，将构建多通道检测和信号处理模块，并将其集成到通用的商用仪器中。第三，对用于无孔径近场扫描红外显微镜的尖锐金属尖端的改进设计进行测试和优化。利用无孔径近场显微镜在100纳米横向分辨率下对人造聚合物表面进行红外光谱化学成像已经在初步工作中得到证实。这一探索性提议的目标是确定是否可以获得成像生物分子的有用信息，以及是否可以开发出其他科学家可以随时使用的技术。

DESCRIPTION (provided by applicant): The goal of this project is to develop an attachment for a scanning probe microscope that enables high throughput, apertureless, near field infrared microscopy (ANSIM). The development of this instrument will enable sensing applications that require the characterization of extremely small regions of complex biological materials on surfaces. The proposed near field instrument will be able to perform IR absorption spectroscopy at less than 100nm lateral spatial resolution. The ANSIM attachment will be designed to be small and portable, so that replicas of this attachment may become a practical add-on to other atomic force microscopes (AFMs). The instrument development program has three principal elements. First, infrared (IR) quantum cascade laser arrays will be assembled with the optics for guiding the IR laser light into and out of the microscope. Second, multi-channel detection and signal processing modules will be built and integrated with a common, commercial instrument. Third, improved designs of the sharp metal tip used in an apertureless near-field scanning infrared microscopes will be tested and optimized. IR spectroscopic chemical imaging of manmade polymeric surfaces at 100nm lateral resolution using apertureless near field microscopy has already been demonstrated in preliminary work. The goal of this exploratory proposal is to determine whether useful information can be acquired for imaging biological molecules, and whether technology that would be readily used by other scientists can be developed. The test measurements will concentrate on imaging peptide layers and their secondary structure, primarily using IR active amide bands. This would be the first time IR near field microscopy has been applied to peptide and protein analysis, and would represent a significant step forward in biochemical imaging using scanning probe microscopy. Polyglutamine (PG) and its aggregates have been chosen for demonstration studies because 1) PG has a relatively simple IR spectrum related to its secondary structure and 2) PG structures have been implicated in diseases associated with the deposition of insoluble aggregations of proteins, known as fibrils, in various human organs. To treat or to prevent such diseases, improved ability to observe the formation and the deposition of such insoluble aggregates is required; IR near field microscopy could have considerable impact in this area.