Transmission electron microscopy (TEM) of biological samples has a long history and has provided many important insights into fundamental processes and diseases. While great strides have been made in EM data collection and data processing, sample preparation is still performed using decades-old techniques. Those sample preparation methods rely on extensive macroscale purification and concentration to achieve homogeneity suitable for high-resolution analyses. Noting that relatively few bioparticles are needed to generate high-quality protein structures, this work uses microfluidics that can accurately and precisely manipulate and deliver bioparticles to grids for imaging. The use of microfluidics enables isolation, purification, and concentration of specific target proteins at these small scales and does so in a relatively short period of time (minutes). These capabilities enable imaging of more dilute solutions and obtaining pure protein images from mixtures. In this system, spatially isolated, purified, and concentrated proteins are transferred directly onto electron microscopy grids for imaging. The processing enables imaging of more dilute solutions, as low as 5 × 10-6 g/ml, with small total amounts of protein (<400 pg, 900 amol). These levels may be achieved with mixtures and, as proof-of-principle, imaging of one protein from a mixture of two proteins is demonstrated.

中文翻译：

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电泳排斥微量样品制备，用于蛋白质的冷冻EM结构测定。

生物样品的透射电子显微镜（TEM）具有悠久的历史，并为基本过程和疾病提供了许多重要见解。尽管在EM数据收集和数据处理方面已取得了长足的进步，但仍使用数十年的技术来​​进行样品制备。这些样品制备方法依赖于广泛的宏观纯化和浓缩，以实现适用于高分辨率分析的均匀性。注意到生成高质量蛋白质结构所需的生物颗粒相对较少，这项工作使用了微流体技术，该技术可以准确而精确地操纵生物颗粒并将其输送到网格进行成像。使用微流体可以实现分离，纯化，在如此短的时间内，可以在较短的时间内（分钟）完成特定目标蛋白的浓缩。这些功能使更多稀溶液成像并从混合物中获得纯蛋白质图像。在该系统中，将空间分离，纯化和浓缩的蛋白质直接转移到电子显微镜格栅上进行成像。该处理可以对更少量的稀释溶液进行成像，低至5×10-6 g / ml，蛋白质总量少（<400 pg，900 amol）。可以通过混合物达到这些水平，并且作为原理证明，证明了从两种蛋白质的混合物中对一种蛋白质进行成像。浓缩的蛋白质直接转移到电子显微镜格栅上进行成像。该处理可以对更少量的稀释溶液进行成像，低至5×10-6 g / ml，蛋白质总量少（<400 pg，900 amol）。可以通过混合物达到这些水平，并且作为原理证明，证明了从两种蛋白质的混合物中对一种蛋白质进行成像。浓缩的蛋白质直接转移到电子显微镜格栅上进行成像。该处理可以对更少量的稀释溶液进行成像，低至5×10-6 g / ml，蛋白质总量少（<400 pg，900 amol）。可以通过混合物达到这些水平，并且作为原理证明，证明了从两种蛋白质的混合物中对一种蛋白质进行成像。