Two-stage robotic crystal mounting of protein crystals for X-ray data collection

We present a new microrobotic system for a crystallographic task called protein crystal mounting, which is the transfer of a crystal from its growth solution onto a tool designed to hold it for X-ray data collection. The system operates autonomously using feedback from a camera looking at the workspace through a microscope. Visual tracking is employed to monitor the location of the selected crystal and control a range of actuators for successful extraction. The task is performed in two stages: First, the crystal is taken from its drop into a pipette and is transported into a cryoprotecting liquid. Second, while in the cryoprotector, it is transferred from the pipette onto a tool to be used for data collection. Key features of this approach are the increased robustness of the system and the avoidance of the damaging effect of direct exposure of the crystal to room conditions. This work is part of a larger effort we have directed at the automation of the high-throughput crystallographic pipeline

Method for acquiring, storing and analyzing crystal images

A system utilizing a digital computer for acquiring, storing and evaluating crystal images. The system includes a video camera (12) which produces a digital output signal representative of a crystal specimen positioned within its focal window (16). The digitized output from the camera (12) is then stored on data storage media (32) together with other parameters inputted by a technician and relevant to the crystal specimen. Preferably, the digitized images are stored on removable media (32) while the parameters for different crystal specimens are maintained in a database (40) with indices to the digitized optical images on the other data storage media (32). Computer software is then utilized to identify not only the presence and number of crystals and the edges of the crystal specimens from the optical image, but to also rate the crystal specimens by various parameters, such as edge straightness, polygon formation, aspect ratio, surface clarity, crystal cracks and other defects or lack thereof, and other parameters relevant to the quality of the crystals