Tech Briefs

Automation of Vapor-Diffusion Growth of Protein Crystals

High-throughput experiments are accelerated through automation of routine operations.

Some improvements have been made in a system of laboratory equipment developed previously for studying the crystallization of proteins from solution by use of dynamically controlled flows of dry gas. The improvements involve mainly (1) automation of dispensing of liquids for starting experiments, (2) automatic control of drying of protein solutions during the experiments, and (3) provision for automated acquisition of video images for monitoring experiments in progress and for post-experiment analysis.

The automation of dispensing of liquids was effected by adding an automated liquid-handling robot that can aspirate source solutions and dispense them in either a hanging-drop or a sitting-drop configuration, whichever is specified, in each of 48 experiment chambers. A video camera of approximately the size and shape of a lipstick dispenser was added to a mobile stage that is part of the robot, in order to enable automated acquisition of images in each experiment chamber. The experiment chambers were redesigned to enable the use of sitting drops, enable backlighting of each specimen, and facilitate automation.

The evaporation of water from the protein solution in each chamber can be controlled independently of the evaporation in the other chambers. Hence, a total of 48 unique evaporation rate-versus-time profiles can be tested simultaneously. Interface software was written for use in controlling all aspects of operation of the system. The software also enables the user to specify the evaporation profile for each chamber and provides for automatic acquisition of the images from each experiment chamber and the storage of the images for later analysis.

This work was done by David T. Hamrick of Diversified Scientific, Inc., and Terry L. Bray of the University of Alabama at Birmingham for Marshall Space Flight Center. For further information, access