Spiral Growth Can Enhance Both the Normal Growth Rate and Quality of Tetragonal Lysozyme Crystals Grown under a Forced Solution Flow

摘要

We measured the normal growth rate of the {110} face (R-110) of tetragonal lysozyme crystals grown by the spiral growth mechanism or the two-dimensional (2D) nucleation growth mechanism under various solution flow rates (0, 8.0, 30, 140, 210 mu m/s), and observed the step morphology using laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM). The R-110 of crystals grown by the spiral growth mechanism was enhanced by solution stirring at all solution flow rates. The aspect ratio, which was defined as the ratio of the long axis to the short axis of the hillock shape, increased at a flow rate under 140 mu m/s with increasing flow rate; that is, impurities were adsorbed less onto the crystal surface at <140 mu m/s. In contrast to spiral hillocks, the R-110 of crystals grown by the 2D nucleation growth mechanism was inhibited at >140 mu m/s, and the aspect ratio decreased monotonically as the solution flow rate increased; that is, the impurity effect became more significant. These results indicate that spiral hillocks are less affected by impurities transported by a forced solution flow. We concluded that in the case of the spiral growth mechanism, a flow rate of 30 to 140 mu m/s is suitable for high quality crystal growth with a faster growth rate.