Crystallization of Proteins: Principles and Methods - Molecules: Nucleation, Aggregation and Crystallization - page 125

(a) (b)

Fig. 9. Dialysis buttons are either machined from transparent perspex or injection
moulded from polystyrene, and are the size of a small button. The sample is placed in
this chamber so as to create a slight dome of liquid at the top of the button. A dialysis
membrane is placed over the top of the button/sample and is held in place with an O-ring.
The O-ring is held in place by a groove in the dialysis button. (a) Microdialysis buttons
from Hampton research (HR3-336). (b) Microdialysis rods from Hampton research
(HR3-348).

along with the membrane is then immersed into a well containing the
precipitant to allow for equilibration.
A modified microdialysis button called the Microdialysis Rod (Fig. 9b),
has been designed and manufactured for use in protein crystallization.
This new apparatus allows easier handling and storage, and provides ver-
satility to users (Lee, Cudney, 2004).

Conclusions

Before embarking on crystallization trials, systematic studies on the
macromolecule is an important factor to be considered for success.
A phase diagram can form the basis of the design of crystallization
experiments. It will enable the experimenter to manipulate the phase
diagram and actively control the crystallization environment in order to
lead to crystal growth in the direction that will produce the desired
results.