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3.1.8
Exchanging the Micropipette
During the course of a microinjection procedure, it may be necessary to exchange
micropipettes. One effective method of doing this is to incorporate the ‘Home’ function in the
following manner:
1.
Center the micropipette in the microscope field of view and above the dish by 3 mm, and
press and hold down the ‘Work’ key to memorize the coordinates.
2.
Press ‘Home’, and the mechanical will move to the upper and outer limits of travel. The
movement from ‘Work’ to ‘Home’ can be paused at any time by pressing ‘Home’ or ‘Work’
briefly. Movement to ‘Home’ can be resumed by pressing ‘Home’ again briefly.
3.
Unlock and open the swing gate to access the top of the micropipette holder.
4.
Taking care not to disturb the position of the micropipette holder in its clamp, loosen the
chuck on the front of the micropipette holder and remove and discard the micropipette
safely.
5.
Fit a new micropipette into the holder and lock the chuck in place.
6.
Return the swing gate to the working position and lock it in place.
7.
Press ‘Work’ to move the micropipette above the injection chamber and in the field of
view.
CAUTION: It is important to remember that when activating the ‘Work’ function, the
micromanipulator records the position of the micromanipulator motors, not the micropipette
tip. Therefore, if a micropipette is being replaced by one that is longer, the micropipette may
crash into the bottom of the injection chamber upon returning to ‘Work’ from ‘Home’.
Several measures, taken alone or together, can prevent this: When returning to ‘Work’ from
‘Home’, approach the injection chamber with the new micropipette in stages by toggling the
‘Work’ key. Once the micropipette tip is close to the bottom of the injection chamber, use
small movements on low speeds with the joystick.
3.2
Starting a Microinjection Session
3.2.1
Setting up the Microscope
1.
Locate the correct focal plane for the microinjection chamber in the following manner:
2.
Place a representative microinjection dish, chamber or slide on the stage of the
microscope, set the microscope to its lowest possible magnification, and focus on the
uppermost surface of the bottom of the chamber (an effective method is to draw a pen
mark in the center of the chamber to be used, and focus on that). This establishes the
correct microscope focal plane for microinjection.
3.
The microinjection chamber can now be removed and, as long as the microscope focus is
not disturbed, the micropipette tip can be manipulated into the optical axis, above the
bottom of the injection chamber.
3.2.2
Setting up the Micromanipulator
1.
Remove the micropipette holder (rod) from the clamp of the mechanical.
2.
Activate the ‘Setup’ key on the rear of the joystick. This ensures that the motors are in
their optimum positions prior to starting ‘Work’.
XENOWORKS MICROMANIPULATOR SYSTEM (TOUCHDECLUTCH) OPERATION MANUAL – REV.
