NEW CRYSTALLIZATION SYSTEMS ENVISIONED FOR MICROGRAVITY STUDIES

Laboratory-based systems have been constructed to demonstrate two meth ods which will allow for dynamic control of protein-crystal growth. Th e technologies developed in these systems will be incorporated into fu ture flight hardware for use in microgravity studies. The first method uses a precisely controlled vapor-diffusion approach to monitor and c ontrol protein-crystal growth. This approach utilizes a humidity senso r and various interfaces under computer control to effect virtually an y evaporation rate from up to 40 different growth solutions simultaneo usly. A static laser-light-scattering sensor can be used to detect agg regation events and trigger a change in the evaporation rate for a gro wth solution. The second method exploits the varying solubility of pro teins versus temperature to control the growth of protein crystals. Th is approach utilizes miniature thermo-electric devices under microcomp uter control which change temperature as needed to grow crystals of a given protein. Complex temperature ramps are possible using this appro ach. A static laser-light-scattering probe is also included in this sy stem as a noninvasive probe for detection of aggregation events. The s ystems constructed demonstrate significant advances in the ability of researchers to gain control of the protein-crystal growth process and will provide tremendous opportunities for microgravity research.