A New Correlative Approach for Structure Determination & Imaging of Molecular Materials

电子显微镜（EM）现在是纳米级成像和分析不可或缺的工具，使工程，物理和生命科学的许多重要发现成为可能。它被广泛接受的结构，化学和动态信息的水平，目前可访问的EM是有限的材料稳定性下的电子束和/或时间分辨率的数据捕获系统，而不是由显微镜分辨率。最近开发的快速像素化电子相机（EC）为研究具有挑战性的分子和电子束敏感材料创造了一个新的范例，这些材料通常与传统的EM环境（真空，电离辐射等）不兼容。它们的稳定和有效分析需要低剂量，高灵敏度和超快数据采集方法的组合，通常与低温稳定相结合。在这里，我们寻求安装一对互补的高性能和直接检测电子相机（HP-EC和DD-EC）在两台透射电子显微镜上（TEM：Jeol 2100 Plus和2100 F），安装在跨学科的纳米和微米研究中心（nmRC），具有相关的高倾斜，低温转移TEM保持器（HT-CTH）和扫描TEM（STEM）衍射系统控制，在英国建立一个新的研究能力，用于相关的形态学和分子动力学研究。低剂量和/或低温稳定成像将用于快速获取倾斜系列，用于材料的断层扫描重建，大大提高了信息含量，用于水凝胶与细胞/支架相互作用的研究。超快速动态成像将用于实时观察化学反应，用于催化剂和能源材料的开发。这种EC能力还将提供用于亚微米尺寸的超分子晶体的结构测定的微晶电子衍射（microED），用于能量有效的分离反应和药物递送策略;同时去除生长大分子晶体以促进结构测定的要求。相关的操作方法将用于研究功能化框架材料，具有前所未有的空间和时间分辨率，针对气体储存和分离反应，细胞/水凝胶相互作用和下一代电子产品。该设备还将强调最近的进展，相关的，低温成像的长度尺度（CLSM到FIBSEM，到OrbiSIMS和TEM），使用的协议率先在UoN（EP/S 021434/1）。近年来，超快速/敏感的CMOS芯片的发展已经彻底改变了EM，其中快速获取图像的光束敏感的样品在低通量条件下是必需的。事实上，cryo-EM（2017年诺贝尔化学奖）就是以这种EC为基础的，它能够快速采集和汇总大型低对比度图像数据集。简而言之，最先进的HP-EC将提供x16的视野改善（具有相同的分辨率水平），与我们现有的探测器能力相比，数据采集速率增加了10倍（2100 Plus），非常适合低温、低剂量、断层扫描研究;随着重建数据集的获取变得容易（一分钟而不是一小时），提高了生产率。与我们现有的探测器能力（2100 F）相比，DD-EC将提供x4的视野改善以及x100的数据采集速率增加，适用于实时（1500 fps）跟踪化学反应。当与自动对齐和实时漂移校正相结合时，这种能力将加速使用microED表征的功能化框架材料的开发。因此，我们寻求维持和提升广泛的跨学科材料科学研究计划，使UoN，更广泛的东米德兰兹郡和整个英国的EPS研究社区受益。

Electron microscopy (EM) is now an indispensable tool for nanoscale imaging and analysis, enabling many important discoveries across the engineering, physical and life sciences. It is widely accepted that the level of structural, chemical and dynamic information currently accessible by EM is limited by material stability under the electron beam and/or the temporal resolution of the data capture system, rather than by microscope resolution. Recently developed fast-pixelated electron cameras (EC) have created a new paradigm for the investigation of challenging molecular and e-beam sensitive materials that are generally incompatible with conventional EM environments (vacuum, ionising radiation etc.). Their stabilisation and effective analysis necessitate combinations of low-dose, high-sensitivity and ultra-fast data acquisition approaches, often combined with cryogenic stabilisation. Here, we seek to install a complementary pair of high-performance & direct-detection electron cameras (HP-EC & DD-EC) on two transmission electron microscopes (TEM: Jeol 2100Plus and 2100F), housed in the interdisciplinary Nanoscale & Microscale Research Centre (nmRC), with associated high-tilt, cryo-transfer TEM holder (HT-CTH) and scanning TEM (STEM) diffraction system control, to create a new research capability in the UK for correlated morphological & molecular dynamic investigations.Low-dose and/or cryogenically stabilised imaging will be used for the rapid acquisition of tilt-series for the tomographic reconstruction of materials, with greatly improved information content, for investigations of hydrogels to cell/scaffold interactions. Ultra-fast, dynamic imaging will be used to observe chemical reactions in real-time, towards the development of catalysts & energy materials. This EC capability will provide also for microcrystal electron diffraction (microED) for structure determination of sub-micron sized supramolecular crystals, for energy efficient separation reactions & drug-delivery strategies; whilst removing the requirement to grow large molecular crystals to facilitate structure determination. Correlated in operando approaches will be used to investigate functionalised framework materials, with unprecedented spatial & temporal resolution, targeting gas storage and separation reactions, cell / hydrogel interactions, and next generation electronics. This equipment will also underscore recent advances in correlative, cryogenic imaging across the length scales (CLSM to FIBSEM, to OrbiSIMS & TEM), using protocols pioneered at UoN (EP/S021434/1).In recent years, development of ultra-fast / sensitive CMOS chips has revolutionised EM, where rapid acquisition of images from beam-sensitive samples under low fluence conditions is required. Indeed, cryo-EM (2017 Nobel Prize for Chemistry) is underpinned by such ECs, enabling rapid acquisition & summation of large, low-contrast image datasets. In simple terms, a state-of-the-art HP-EC will provide for an x16 improvement in field of view (with same level of resolution), combined with x10 increase in data acquisition rate, compared to our existing detector capability (2100Plus), ideal for cryogenic, low-dose, tomographic investigations; with acquisition of data-sets for reconstruction becoming facile (a minute rather than an hour), improving productivity. The DD-EC will provide for an x4 improvement in field of view combined with x100 increase in data acquisition rate, compared to our existing detector capability (2100F), appropriate for following chemical reactions in real-time (1500 fps). When combined with automatic alignment and real-time drift-correction, this capability will accelerate the development of functionalised framework materials, characterised using microED. Accordingly, we seek to sustain and elevate a broad range of interdisciplinary materials science research programmes, benefiting EPS research communities at the UoN, the wider East Midlands and across the UK.