MRI: Acquisition of a Field Emission Cryo-Scanning Electron Microscope for Nanocharacterization and Patterning of Soft Materials

0922522LiberaStevens理工学院技术概述：该项目应用一种最先进的新型低温扫描电子显微镜(SEM)，以高空间分辨率测量软材料的形态。这种新型显微镜将推进史蒂文斯理工学院的十多个研究项目，并使他们能够遵循重要的方向，放大他们正在进行的和预期的目标。都是软性材料吗？要么是合成聚合物，要么是生物结构，或者两者的组合。正在研究的材料包括：自组装、弱聚电解质、响应性胶束；纳米颗粒复合材料；模仿自然骨的可降解支架；抗感染整形外科植入物；天然细胞外基质；以及合成纳米纤维细胞外基质。合成的和天然的聚合物由于其辐射敏感性、弱的本征对比度和对电荷的敏感性，是电子显微镜研究中具有挑战性的材料。这种新型显微镜提供了由场发射(FEG)电子源在低电压下实现的可控电子加速电压；可减少样品充电的气体补偿；可将所需入射剂量降至最低的高效电子探测器；强大的数字图像采集/处理方法；用于研究冷冻水合物材料的低温成像能力；以及用于强大的电子束曝光的硬件/软件。所有这些特征在新显微镜取代的扫描电子显微镜上要么是不充分的，要么是不可用的。重要的是，新的扫描电子显微镜被安置在一个中央用户设施中，从高中到研究生都有成功的多学科培训的历史。用户通过集中动手的自我使用练习和研究生讲座/实验室课程工作获得大量培训。除了为直接的史蒂文斯研究社区服务外，该仪器还通过与史蒂文斯创新工程和科学教育中心(一个老牌的K-16扩展组织)和美国化学学会的项目种子计划的合作活动，在社区扩展和教育中发挥重要作用。莱曼摘要：扫描电子显微镜(SEM)用于研究材料表面的放大倍数约为20到500,000倍。它们可以提供有关材料结构和组成的重要信息。所谓的软材料，如塑料和生物组织，通常比金属或半导体更难用电子显微镜进行研究，因为软材料可能会因为显微镜中使用的电子而带电和发生化学变化。在史蒂文斯理工学院有十多个研究项目，所有这些项目都涉及软材料，其进展受到需要做更多和更好的扫描电子显微镜成像和分析的需要的限制。最新的扫描电子显微镜具有创新的功能，可以帮助史蒂文斯的研究人员克服样本充电和化学损坏的问题。为了利用这些优势，这个项目正在使用一种新的、最先进的扫描电子显微镜来测量软材料的形态，并帮助史蒂文斯的研究人员做出新的发现。例如，这些科学家正在利用显微镜开发新的药物输送方法，使髋关节和膝盖植入物更具抗感染能力，并帮助治愈主要的骨折。由于这种新的显微镜是一种复杂的仪器，它被安置在一个实验室里，实验室里有专门的工作人员和设施来维护显微镜，并为大学生提供充分利用这一新工具所需的高级培训。然而，重要的是，显微镜的许多方面都相对容易使用和理解，因此这款显微镜还通过各种高中外展项目帮助史蒂文斯与周围社区建立联系，这些项目旨在让更多的年轻人意识到科学和工程并对其感兴趣。

0922522LiberaStevens Institute of TechnologyTechnical Summary: This project applies a new, state-of-the-art, cryo-scanning electron microscope (SEM) to measure soft-materials morphology at high spatial resolution. This new microscope will advance over ten research projects at Stevens Institute of Technology and enable them to follow important directions that amplify their ongoing and anticipated aims. All involve soft materials ? either synthetic polymers, biological structures, or combinations of the two. Among the materials being studied are: self-assembled, weak-polyelectrolyte, responsive micelles; nanoparticle composites; degradable scaffolds that mimic natural bone; infection-resistant orthopedic implants; natural extracellular matrix; and synthetic nanofiber extracellular matrices. Synthetic and natural polymers are challenging materials to study by electron microscopy because of their radiation sensitivity, weak intrinsic contrast, and susceptibility to electrical charging. This new microscope provides controllable electron accelerating voltages enabled at low voltages by a field-emission (FEG) electron source; gas compensation to mitigate specimen charging; high-efficiency electron detectors that minimize the required incident dose; robust methods for digital image acquisition/processing; cryo-imaging capabilities for studying frozen-hydrated materials; and hardware/software for robust electron-beam lithography. All of these features are either inadequate or unavailable on the SEM the new microscope replaces. Importantly, the new SEM is housed in a central user facility with a history of successful multidisciplinary training that spans high school through post-graduate school. Users receive substantial training both by concentrated hands-on self-user practice and by graduate lecture/lab course work. In addition to serving the immediate Stevens research community, the instrument plays an important role in community outreach and education by way of collaborative activities with the Stevens Center for Innovative Engineering and Science Education, an established K-16 outreach organization, and the Project SEED program of the American Chemical Society.Layman Summary: Scanning electron microscopes (SEMs) are used to study the surfaces of materials at magnifications between about 20 and 500,000 times. They can provide important information about the structure and composition of materials. So-called soft materials, such as plastics and biological tissue, are typically more challenging to study by electron microscopy than metals or semiconductors, because soft materials can become both electrically charged and chemically changed by the electrons used in the microscope. At Stevens Institute of Technology there are more than ten research projects, all of which involve soft materials, whose progress is limited by the need to do more and better SEM imaging and analysis. The newest scanning electron microscopes incorporate innovative features that can help Stevens researchers overcome the problems of specimen charging and chemical damage. To take advantage of these, this project is using a new, state-of-the-art, SEM to measure soft-materials morphology and help Stevens researchers make new discoveries. These scientists are, for example, using the microscope to develop new ways to delivery drugs, to make hip and knee implants more infection resistant, and to help heal major bone fractures. Because this new microscope is a complex instrument, it is housed in a laboratory with a dedicated staff and facilities to both maintain the microscope and provide the advanced training needed for university students to make the best use of this new tool. Importantly, however, many aspects of the microscope are relatively easy to use and understand, so this microscope is also helping Stevens develop connections to the surrounding community through a variety of high-school outreach programs designed to get more young people aware of and interested in science and engineering.