*Article* **Microplates for Crystal Growth and in situ Data Collection at a Synchrotron Beamline**

**Miao Liang 1,2, Zhijun Wang 1,3, Hai Wu 1,2, Li Yu 1,2, Bo Sun 1,3, Huan Zhou 1,3, Feng Yu 1,3, Qisheng Wang 1,3,\* and Jianhua He 1,4,\***


Received: 30 July 2020; Accepted: 6 September 2020; Published: 9 September 2020

**Abstract:** An efficient data collection method is important for microcrystals, because microcrystals are sensitive to radiation damage. Moreover, microcrystals are difficult to harvest and locate owing to refraction effects from the surface of the liquid drop or optically invisible, owing to their small size. Collecting X-ray diffraction data directly from the crystallization devices to completely eliminate the crystal harvesting step is of particular interest. To address these needs, novel microplates combining crystal growth and data collection have been designed for efficient in situ data collection and fully tested at Shanghai Synchrotron Radiation Facility (SSRF) crystallography beamlines. The design of the novel microplates fully adapts the advantage of in situ technology. Thin Kapton membranes were selected to seal the microplate for crystal growth, the crystallization plates can support hanging drop and setting drop vapor diffusion crystallization experiments. Then, the microplate was fixed on a magnetic base and mounted on the goniometer head for in situ data collection. Automatic grid scanning was applied for crystal location with a Blu-Ice data collection system and then in situ data collection was performed. The microcrystals of lysozyme were selected as the testing samples for diffraction data collection using the novel microplates. The results show that this method can achieve comparable data quality to that of the traditional method using the nylon loop. In addition, our method can efficiently and diversely perform data acquisition experiments, and be especially suitable for solving structures of multiple crystals at room temperature or cryogenic temperature.

**Keywords:** microcrystals; microplate; grid scanning; in situ data collection
