IDBR: Type A, An Ultraprecise and Ultrastable Atomic Force Microscope for Multimodal Characterization of Biological Molecules and Materials

该奖项由生物基础设施部（生物科学理事会）的生物研究仪器开发项目授予科罗拉多大学博尔德分校，由材料科学部（数学和物理科学理事会）的生物材料项目共同资助。原子力显微镜（AFM）是一种用于在纳米尺度上对物质进行成像、测量和操作的工具，它通过使用一种被称为悬臂的机械探针来收集表面信息。AFM在生物学中的应用包括理解单个蛋白质的折叠和展开。蛋白质的功能需要适当的折叠，而错误的折叠会导致阿尔茨海默氏症等疾病。在折叠研究中，力稳定性是至关重要的，因为折叠和展开速度对亚皮牛顿（pN）的力变化很敏感。该项目将具有成本效益的悬臂微加工与新型光学检测相结合，在1pn下实现了1600倍的时间分辨率提高。提出的发展将有利于生物领域，以及材料科学。项目活动将为本科生和研究生提供优秀的跨学科培训。该项目的两个目标是开发用于生物测量的下一代原子力显微镜，实现(1)世界领先的短期力精度和最先进的力稳定性；(2)扩展其成像能力，超越地形，以更高的分辨率绘制化学成分。第一个目标将在蛋白质折叠测定的背景下进行演示。为了提供10-100倍的力稳定性改进，将开发一种新的悬臂运动差分检测系统。该系统将使用微小的光斑尺寸（~2 ìm）来检测超小型（L = 10 ìm）悬臂梁，这些悬臂梁已经通过聚焦离子束进行了修改，以提高性能。这些悬臂梁可实现世界领先的力精度，并具有长时间（100秒）的亚pn稳定性。第二个项目目标侧重于使用提供3.5 nm分辨率的新拉曼成像模式对材料进行化学表征。通过将多个激光束从AFM尖端散射，所提出的AFM将协同融合这种令人兴奋的成像模式与世界领先的尖端样品稳定性，并建立在PI？实验室：将多个激光器集成到AFM中。最初的研究将集中在DNA包裹的碳纳米管上。研究结果将通过论文、演讲和专利的形式进行传播。受益于该项目的生物研究团体包括单分子生物物理学、膜蛋白生物学、细胞结构、蛋白质折叠以及其他学科（如物理学、材料科学、纳米技术）。与AFM制造商（包括Asylum Research和Molecular Vista）的合作将促进更广泛的用户基础的采用。

This award to the University of Colorado at Boulder, by the Instrument Development for Biological Research program, in the Division of Biological Infrastructure (Biological Sciences Directorate),is jointly funded by the Biomaterials Program in the Division of Materials Science (Math and Physical Sciences Directorate). Atomic force microscopy (AFM) is a tool used for imaging, measuring, and manipulating matter at the nanoscale, and gathers surface information by using a mechanical probe called a cantilever. Applications of AFM in biology include understanding the folding and unfolding of individual proteins. Protein function requires proper folding, and misfolding can lead to diseases such as Alzheimer's. In folding studies, force stability is critical since the folding and unfolding rates are sensitive to sub-piconewton (pN) changes in force. This project merges cost-effective micromachining of cantilevers with a novel optical detection to achieve a 1,600-fold increase in temporal resolution at 1 pN. The proposed developments will benefit the fields of biology, as well as materials science. Project activities will provide excellent interdisciplinary training for undergraduates as well as graduate students.The twin goals of this project are to develop a next generation AFM for biological measurements that achieves (i) world-leading short-term force precision coupled with state-of-the-art force stability and (ii) extend its imaging capability beyond topography to map chemical composition with enhanced resolution. The first goal will be demonstrated in the context of protein folding assays. To provide a 10-100-fold improvement in force stability, a novel differential detection system of cantilever motion will be developed. This system will use a tiny spot size (~2 ìm) to enable detection of ultra-small (L = 10 ìm) cantilevers, which have been modified by a focused ion beam for improved performance. These cantilevers enable world-leading force precision coupled with sub-pN stability over long periods (100 s). The second project goal focuses on chemical characterization of materials using a new Raman imaging modality that offers 3.5-nm resolution. By scattering multiple laser beams off the AFM tip, the proposed AFM will synergistically merge this exciting imaging modality with the world-leading tip-sample stability and builds upon a strength of the PI?s lab: integrating multiple lasers into an AFM. Initial studies will focus on DNA wrapped carbon nanotubes. Results will be disseminated via papers, presentations, and patents. Biological research communities that will benefit from this project include single-molecule biophysics, membrane protein biology, cellular structure, protein folding, as well as other disciplines (e.g., physics, material science, & nanotechnology). Collaborations with AFM manufacturers (including Asylum Research and Molecular Vista) will facilitate adoption by a wider user base.