Demo protocol: Glycerol spotting on glass

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.

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.

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