Section 5.1.2.2.3. Thumb pump

The thumb pump is a simple micropipetting device for transferring very small amounts of liquid in a highly controlled manner, making it an extremely useful tool for directly transferring protein crystals from solution to capillary, thus minimizing the chance of crystal damage. This simple device allows the experimenter to have much more control over volume transfers than any other device we have tried. The mechanism is simple and easy to operate. The device shown in the illustration can be held and manipulated with one hand. The capillary is held firmly in place and the pipetting action is controlled by a thumb wheel (part of the thumb pump), which affords a great deal of control over the volume of liquid being transferred with the crystal.