Instruction manual

PV820/PV830 Pneumatic PicoPump

World Precision Instruments 15

For ejected volumes less than 1nL, visual inspection in air proves to be difﬁ cult due

to rapid evaporation. The same technique may be used though if the drop is kept

submerged under oil. Droplets may seem to disappear after emergence from the tip.

Sometimes this is due to creepage of the aqueous ﬂ uid back along the outside shank of

the micropipette. This creepage may be decreased by silanizing the outside of the pipette.

If you choose to silanize only the outside of the pipette, the PicoPump may be used to

applying air ﬂ ow through the pipette during the silanization.

TIP: Precise assays of ejected volume may also be obtained through various

radioisotopic methods. See the bibliography for further information.

A slight deﬂ ection of the micropipette tip may be noticed during the application of the

pressure pulse. This deﬂ ection may be eliminated by ensuring that the micropipette is

ﬁ rmly seated in the holder and that the holder is ﬁ rmly held by a manipulator.

Rate Calibration using a Known Volume

We can calculate the volume of liquid contained in a 1mm length of a glass pipette, if

we know the inner diameter (ID). Then, we can inject that known volume and measure

the time it takes to inject it. From this we can calculate the rate of injection. For example,

if the volume in 1mm of glass with 0.58μm ID (WPI #1B100) is 264nL, and it takes 30

seconds to inject that volume, then the ﬂ ow for 1 second is 264nL/30s or 8.8nL/second,

and a 1nL volume then takes 0.113 seconds to inject.

This method is discussed in the following JoVE video: http://www.jove.com/video/2079/

intravenous-microinjections-zebraﬁ sh-larvae-to-study-acute-kidney.

In the Jove video, the capillary tip is 10–20μm. By following these steps, we are able to

calculate the timing needed to deliver a 1nl injection by counting the time between 1mm

marks as the ﬂ uid is injected.

NOTE: The PicoPump timing should not be adjusted to go below 10–15ms as an

absolute minimum, since it takes 6–10ms for the pressure relay to respond.

1. Fill a small dish with mineral oil and place it under a stereo microscope.

2. Turn on your air and vacuum pumps, and set your hold pressure and your eject

pressure. The proper settings must be determined experimentally. Turn on the

PicoPump.

NOTE: The eject pressure must exceed the hold pressure in order to eject the ﬂ uid.

3. Use a pipettor to inject a 10μl sphere of ﬂ uid into the mineral oil.

4. Using a ﬁ ne pointed permanent marker, mark the injecting micropipette at 1mm

increments.

5. Mount your “graduated” micropipette on the PicoNozzle that is connected to the

Eject port on the PicoPump.

6. Submerge the tip of the pipette in the ﬂ uid droplet you placed in the mineral oil.

Front ﬁ ll the injecting pipette using the Vac (PV830)/Vent (PV820) setting on the