Diffusion-controlled crystallization apparatus for microgravity (DCAM): flight and ground-based applications

A versatile microdialysis counterdiffusion apparatus was developed in response to special exploratory opportunities for long-duration protein crystal growth experiments presented by the US and Russian Space Program. Challenged to reduce man-tended dependence during this phase, the hardware was designed to eliminate in-flight activation or deactivation. In addition, a disposable interface was incorporated in the design to allow for improved logistics and handling during the pre-flight loading and post-flight distribution of the flight samples for each experiment. The hardware is referred to as the diffusion-controlled crystallization apparatus for microgravity or DCAM (pronounced "dee-cam") which utilizes the dialysis method and allows the equilibration rate of each individual experiment to be passively controlled from several days to several months. Precision control of the rate of approach to supersaturation has routinely produced macro (5 mm to 1.25 cm) crystals for a variety of proteins in this hardware. A description of the hardware and preliminary results from a series of US Shuttle/Mir flight experiments are presented. (C) 1999 Elsevier Science B.V. All rights reserved.