Flow suspended solution growth-A new method

We report on the development of a new method of crystal growth from the solution in which the growing crystal is freely suspended in the flowing mother solution. We call this method flow-suspended solution growth. Growth of the crystal is possible without any wall contact in up-flow of supersaturated solution in a conical vertical tube called growth reactor. The velocity profile of the solution in the tube around the growing crystal centres the object on the axis of the tube. This is possible under certain limitations of the crystal size and of the density difference Δρ between crystal and solution. We describe and discuss these limitations. The method was successfully tested with solution growth of KAl(SO4)2·12H2O from watery solution. We report some practical information like the relationships between crystal size, Δρ, diameter of the growth reactor and the needed volume flow rate to suspend the crystal. We report the possibility of long-time unattended steady growth and an easy seeding and harvesting action. Flow-suspended solution growth has the potential for controlled protein crystal growth (if miniaturized) and for the growth of biological objects like embryos.