Q: What is the best way to clean Solid,
Grooved and Slot Replicator pins if they become dirty?
A: Although the pins should never become dirty if they
are cared for properly during regular use, they can be easily cleaned by
sonication for ~20 seconds in a bath that contains 1% Micro 90
® cleaning solution. Micro 90® can
be purchased from International Products Corp. Phone (609) 386-8770.
Instrument Company (800) 323-4340 sells an inexpensive ultrasonic cleaner, model
P-08857-02 that is of the ideal size for cleaning all replicators.
next best way is to clean the pins with Ivory dishwashing soap and the
425 brush. Once the pins are clean we recommend a final dip in the
110 Pin Cleaning Solution.
Q: My slot pins are not wicking up the solution or the slots
are not filling all the way up. My DNA is only 1 ng/ul and is in a buffer
that I cannot add surfactant to (detergent, protein, carbohydrate or carrier
DNA or RNA).
A: Just water or NaOH without surfactants is very
hydrophobic and will not fill the slots by capillary action. Dipping the
pins in ETOH and flaming them prior to picking up the solution changes the
surface tension factor on the pin and allows the slots to fill. If it is
not possible to flame your pins, then treat them once in our new pin Pin
Cleaning Solution VP
110. See the V&P Pin Cleaning
Solution page for more information about how this
cleans the pin and changes the surface tension on the pin slot.
Irregular spots can also be caused by lint in the slots from
paper towels used to blot the Replicator between cleaning baths. This can be
prevented by placing a lint free blotting paper
522) over the paper towel.
Q: The size of my solid Replicator pin spots on membrane are
irregular. My DNA is only 1 ng/ul and is in a buffer that I can not add
surfactant to (detergent, protein, carbohydrate or carrier DNA or RNA).
A: Just water or NaOH without surfactants is very
hydrophobic and will form irregular sized hanging drops on solid Replicator
pins. Dipping the pins in ETOH and flaming them prior to spotting changes
the surface tension factor on the pin and gives much more uniform spot sizes.
If it is not possible to flame your pins then treat your slot pins once in our
new Pin Cleaning Solution VP 110. See the
V&P Pin Cleaning Solution page
for more information about how this cleans the pin and changes the surface tension on the pin.
Q: How do I test the Replicators prior to use?
A: Make an aqueous solution containing the buffer or
media you will be transferring. Add to that solution the substance (DNA,
RNA, protein, carbohydrate, surfactant, etc.) you wish to test in approximately
the concentration it will represent in your actual solution. If that is
not possible use a 1% solution of Bovine Serum albumin. Add several drops
of blue food coloring to this solution. It is very
important that a substance (DNA, RNA, protein, carbohydrate or surfactant) be
added to the water as water has a very high surface tension and just water with dye will result in erratic volume transfers.
If you can not add
surfactants to your buffer, then change the surface tension of the pins by by
dipping in ETOH and flaming prior to dipping in the test solution. The
surface tension on the pins can also be changed by cleaning the pins in our
new V&P Pin Cleaning Solution (VP 110).
See the V&P Pin Cleaning Solution page for more
information about how this cleans and changes the
surface tension on the pin.
A2: We provide a complete protocol which will help you to determine
the volume of your liquid that is transferred.
See technical note 65.
Q: What determines the
volume of liquid transferred by the Replicator pins?
solid Replicator pin
transfers liquid on two surfaces: a small hanging drop forms on
the tip of the pin, and secondly, on the sides of the pin. The volume of liquid transferred depends upon the
diameter of the pin, the chamfer of the tip, the flat spot, the
speed that the pins are removed from the liquid, the surface
tension of the liquid, the surface tension of the pin, the depth
to which the pin is wetted, the diameter of the well the pin is
inserted into, and the distance between the pin and the well
wall. Although each of these factors may make small changes in
the volume of liquid transferred, we have found that the pin to
pin reproducibility is better than 5%.
One of the variables that you can
easily control is the speed with which you remove the pins from
the liquid - the slower the removal, the smaller the drop size on
both surfaces. You can also add surfactants, proteins or solvents
to the liquid or change the pH to change the surface tension
Changing the surface tension on the pin can be
done in several ways: 1. dipping the pin in ETOH and flaming, 2. cleaning the
pin with the V&P Pin Cleaning Solution (VP 110) or 3. washing in a detergent such as
Ivory dishwashing soap.
The LIBRARY COPIER™ (VP 381) is used to keep all the pins in the middle of
the wells and to keep from knocking off the hanging drop. Although there are several different variables, we have
determined that with nearly all the biological specimens that are
transferred, these variables are negligible and thus the volume
transferred remains the same for all the pins even when
significant differences in protein concentration exist. Furthermore there is excellent reproducibility between different
Replicator stampings or blots.
The liquid transferred to
membranes or agar comes only from the hanging drop on the tip of
the pin so by changing the chamfered spot diameter and/or the pin
diameter and shape we can offer a variety of custom delivery
volumes. Contact us with your special needs.