How can I perform glycerol spotting on glass with FluidFM?
A smooth start into the world of FluidFM
This protocol aims to both show functionality of the FluidFM setup and provides inexperienced users with a convenient and easy start into the world of FluidFM. Because glycerol does not evaporate, the most common cause to end a probe lifetime is excluded: drying out.
Using glycerol in a nanopipette, this protocol will allow the user to print micron-sized spots on any glass-surface, in air. The spot will be visible with 20x magnification or larger.
(Optional: Mix with a fluorescent tracer of choice)
FluidFM Nanopipette, 2 N/m
Glass bottom container or glass slide
PREPARE FLUIDFM SETUP
Fill probe with ink
Align the laser and optimize the signal
Fill the probe
Apply 1000 mbar until glycerol reaches probe aperture
The glycerol will not exit the probe at this pressure
Apply 20 mbar pressure to prevent air coming in from the front
Go to the sample
Approach to the surface
Retract 20 um from surface
SPOTTING A PATTERN
Use an idle pressure of 0 mbar between two spots
Spot the pattern of your choice with following parameters:
0-20 mbar will result in tiny spots (<1 um)
20-100 mbar will result in ~ 5 um spots
Setpoint 20 nN o Contact time 300 ms
Approach speed 10 um/s
Retract speed 30 um/s
Retract distance 10 um
In the image, the glycerol was mixed with a fluorescent tracer for maximum visibility
AFTER THE EXPERIMENT
The probe can be stored up to several days in air
A dark, dry and cool environment is recommended.