A crystallization plate for controlling evaporation in hanging drops

Abstract

The modification and use of a crystallization plate for controlling the evaporation in hanging-drop trials is described. In this plate, known as the Nextal Crystallization Tool, each well is sealed by a screw cap that incorporates the cover-slip. Graduation marks were introduced on the outer circumference of the wells to enable accurate and reproducible adjustment of the tightness of the seal on the well. This design allows variable amounts of evaporation without exposing the drop. Crystallization experiments of α-crustacyanin from lobster shell, for which controlled evaporation was applied to regulate the number and size of the crystals, are presented.