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.

INK

Glycerol, pure

(Optional: Mix with a fluorescent tracer of choice)

PROBE

FluidFM Nanopipette, 2 N/m

SAMPLE CONTAINER

Glass bottom container or glass slide

PREPARE FLUIDFM SETUP

• Fill probe with ink

• Mount probe

• 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.