Although microscopes and image-analysis software for electron cryomicroscopy (cryo-EM) have improved dramatically in recent years, specimen-preparation methods have lagged behind. Most strategies still rely on blotting microscope grids with paper to produce a thin film of solution suitable for vitrification. This approach loses more than 99.9% of the applied sample and requires several seconds, leading to problematic air-water interface interactions for macromolecules in the resulting thin film of solution and complicating time-resolved studies. Recently developed self-wicking EM grids allow the use of small volumes of sample, with nanowires on the grid bars removing excess solution to produce a thin film within tens of milliseconds from sample application to freezing. Here, a simple cryo-EM specimen-preparation device that uses components from an ultrasonic humidifier to transfer protein solution onto a self-wicking EM grid is presented. The device is controlled by a Raspberry Pi single-board computer and all components are either widely available or can be manufactured by online services, allowing the device to be constructed in laboratories that specialize in cryo-EM rather than instrument design. The simple open-source design permits the straightforward customization of the instrument for specialized experiments.

中文翻译：

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摇动：简单的超声波冷冻-EM样品制备设备。

尽管近年来用于电子冷冻显微镜（cryo-EM）的显微镜和图像分析软件有了显着改进，但标本制备方法却落后了。大多数策略仍然依赖于用纸吸取显微镜网格以产生适合玻璃化的溶液薄膜。这种方法会损失超过99.9％的应用样品，并且需要几秒钟的时间，从而导致最终溶液薄膜中大分子的气-水界面相互作用出现问题，并使时间分辨研究复杂化。最近开发的自吸式EM网格允许使用少量样品，并且网格条上的纳米线可以去除多余的溶液，从而在从施加样品到冻结的数十毫秒内产生薄膜。这里，提出了一种简单的低温EM样品制备设备，该设备使用超声波加湿器中的组件将蛋白质溶液转移到自芯EM网格上。该设备由Raspberry Pi单板计算机控制，所有组件要么广泛可用，要么可以通过在线服务进行制造，从而使该设备可以在专门从事cryo-EM的实验室而不是仪器设计中构建。简单的开放源代码设计允许直接为特殊实验定制仪器。允许将设备构建在专门从事低温EM而不是仪器设计的实验室中。简单的开放源代码设计允许直接为特殊实验定制仪器。允许将设备构建在专门从事低温EM而不是仪器设计的实验室中。简单的开放源代码设计允许直接为特殊实验定制仪器。