REACH: Robotic Equipment for Automated Crystal Harvesting using a six-axis robot arm and a micro-gripper

In protein crystallography experiments, only two critical steps remain manual: the transfer of crystals from their original crystallization drop into the cryoprotection solution followed by flash-cooling. These steps are risky and tedious, requiring a high degree of manual dexterity. These limiting steps are a real bottleneck to high-throughput crystallography and limit the remote use of protein crystallography core facilities. To eliminate this limit, the Robotic Equipment for Automated Crystal Harvesting (REACH) was developed. This robotized system, equipped with a two-finger micro-gripping device, allows crystal harvesting, cryoprotection and flash-cooling. Using this setup, harvesting experiments were performed on several crystals, followed by direct data collection using the same robot arm as a goniometer. Analysis of the diffraction data demonstrates that REACH is highly reliable and efficient and does not alter crystallographic data. This new instrument fills the gap in the high-throughput crystallographic pipeline.