Microbatch crystallization under oil — a new technique allowing many small-volume crystallization trials

An approach to rapid protein crystallization using very small samples is described. A computer controlled microdispenser is used to make crystallization samples as microbatch droplets under oil. Samples of 1–2 μl are dispensed ready-mixed and with good precision. The samples are protected from evaporation, contamination and physical shock by the oil. When favourable conditions for crystallization have been found using one mode of the system, the size and quantity of crystals are optimized by a second program which generates a set of conditions throughout the area of interest. Crystals of diffraction size and quality have been grown in 1 μl drops.