MRI-R^2: Development of STIM and DATS for Protein and Nanosystem Characterization

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。位于布法罗的纽约州立大学已获得MRI-R2计划的支持，用于开发两种免费仪器：光谱太赫兹成像显微镜(STIM)和动态对准太赫兹光谱(DATS)。这对仪器对于解决一个基本问题是至关重要的：集体运动在蛋白质功能中扮演什么角色？回答这个问题会对生物物理学和生物工程产生直接影响。STIM使蛋白质晶体和固态样品的太赫兹成像具有1微米的分辨率、0.2-7.0太赫兹带宽、4.2K-300K和高达10T的场强。蛋白质和RNA系统处于高度结构化和无定形系统的交叉点。传统的研究这些体系的方法受到来自表面侧链和溶剂的驰豫贡献的背景的限制，以及广泛重叠模式的限制。STIM和DATS通过分子排列和极化调制解决了这些限制，从而确立了结构振动运动的功能重要性。这种仪器极大地提高了我们对蛋白质动力学的理解。此外，技术新兴材料的磁激发、声子频率和载流子传输时间都在太赫兹频率范围内。随着器件尺寸的缩小，人们不能假设材料的整体性质，而局部表征是必不可少的。此外，新兴材料通常没有足够的样本大小或均匀性来进行整体表征。为了探测非均匀性，局域态和相变需要太赫兹显微镜。STIM是一种用于纳米系统测量的高分辨率、高质量的光谱系统。STIM和DATS的发展使结构生物学和凝聚态研究等领域的关键测量成为可能。该仪器直接满足了其他目前的太赫兹仪器所不能满足的需求：1)需要区分蛋白质中的结构运动和扩散表面运动；2)需要电子材料的空间分辨电导张量和自旋光谱；3)需要确定非结晶分子的结构。这个MRI-R2项目促进了多个部门、学校和机构之间的跨学科工作。该系统的开发为研究生和本科生研究人员提供了独特的培训机会。这项MRI-R2活动还包括为我们的GGEMS on the Go计划为7-12年级学生提供的新显微镜展示，以及本科生发现研讨会系列：将科学和工程带入生活。开发工作的结果以及新工具促成的研究成果将发表在同行评议的期刊上，并通过学生和教职员工在区域和国家会议上的陈述进行传播。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Support from the MRI-R2 program has been awarded to SUNY at Buffalo to develop two complimentary instruments: Spectral Terahertz Imaging Microscopy (STIM) and Dynamic Alignment Terahertz Spectroscopy (DATS). This pair of instruments is essential to address a fundamental question: what is the role of collective motions in protein function? Answering this question has an immediate impact on biological physics, and bioengineering. STIM enables terahertz imaging of protein crystals and solid state samples with 1 micron resolution, 0.2-7.0 THz bandwidth, 4.2 K - 300 K and in fields up to 10 T. DATS enables terahertz spectroscopy of electrostatically aligned molecular systems and structural measurements of non-crystallizing molecular systems. Proteins and RNA-systems lay at the intersection between highly structured and amorphous systems. Traditional approaches to studying these systems are limited by background from the relaxational contribution of surface side chains and solvent, and by the broad spectrum of overlapping modes. STIM and DATS address these limitations through molecular alignment and polarization modulation and thereby establish the functional importance of structural vibrational motion. This instrumentation significantly improves our understanding of protein dynamics. Also, magnetic excitations, phonon frequencies and carrier transport times for technologically emerging materials lie in the terahertz frequency range. As device size shrinks, one cannot assume bulk material properties and local characterization is essential. Further, emerging materials often do not have sufficient sample size or uniformity for bulk characterization. To probe nonuniformity, localized states and phase transitions require terahertz microscopy. STIM is a high resolution, high quality spectroscopy system for measurement of nanosystems. The development of STIM and DATS enables critical measurements in fields as diverse as structural biology and condensed matter research. The instrumentation directly addresses needs that other current terahertz instrumentation does not: 1) need to discriminate structural motion from diffusive surface motion in proteins; 2) need for spatially resolved conductivity tensor and spin spectroscopy of electronic materials 3) need for structural determination for non-crystallizing molecules. This MRI-R2 project fosters interdisciplinary work among multiple departments, schools and agencies. The system development offers unique training opportunities for graduate and undergraduate researchers. This MRI-R2 activity also includes a new microscopy exhibit for our GGEMS on the GO program for 7-12 graders and an undergraduate Discovery Seminar Series: Bringing Science and Engineering to Life. Results of the development effort, and of the research enabled by the new instruments, will be published in peer-reviewed journals and disseminated through student and faculty presentations at regional and national meetings.