Magnetically controlled gravity for protein crystal growth

The occurrence of convective flows during crystal growth is believed to adversely affect crystal quality. Space-based crystal growth is therefore actively pursued, particularly for protein crystals, because buoyancy-driven convection is suppressed in microgravity. Here the authors demonstrate that magnetic fields can be used to tune the effective gravity from 1 to -0.15 g during the growth of diamagnetic lysozyme crystals and that convection can be damped, stopped, and even reversed. The growth velocity is strongly reduced in simulated microgravity. This method provides a versatile and accessible way to realize an earth-based tunable gravity environment for crystal growth in which protein crystal quality may be optimized. (c) 2007 American Institute of Physics.