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  Pin Tools


  Everything You Need To Know About Pin Tools But Were Afraid To Ask


The various types of pins we use in our Pin Tools are:
1) Solid  2) Slot  3) Grooved and  4) Bolt type. 

They are usually pressed or screwed into an aluminum base however some float freely in aluminum, PEEK or Delrin frames.  Our pins can also be provided with a hydrophobic/lipophobic coating to reduce non-specific binding of proteins and lipoproteins.  Each pin type uses a slightly different method to pick up and transfer liquid and each has its own advantages.  This page and the tables were designed to help you understand the capabilities of the various pins and then pick the best one for your application.  We make a great variety of pin tools and this page will help you focus on the characteristics that are important in your application.  

When these pin tools are used with the appropriate robot they are very effective in HTS applications, screening for compound activity, making serial dilutions, replicating libraries, making arrays on membranes or slides or reformatting libraries.  See our guide for selecting the appropriate pin for your robot application. 

We have made adaptor mounting plates that allow us to mount our pin tools on 50 different commercial robotic liquid handling robots and we have also made numerous custom mounts for customer built robotic systems.   In many other cases our customers have purchased the pin tool from us and had their own machine shop build an adaptor mount.  Whatever way you select, it is simple solution.

Our manual pin tools and replicators when used with the appropriate registration or indexing tool (Glass Slide Indexer, MULTI-PRINT™, LIBRARY COPIER™, COLONY COPIER™ or Vicki System) are also very effective in making arrays on slides or membranes, replicating or reformatting libraries in 24, 48 96, 384 or 1,536 well microplates, screening compounds or making serial dilutions.

Click here for a document showing Macro-arrays prepared using V&P Scientific’s MultiBlot Repicators and MultiPrint registration devices.


  Cleaning The Pins


The most important aspect of using pin tools is to start with clean pins and then keep them clean so they will consistently deliver the same volume.  We recommend our Pin Cleaning Solution (VP 110) to clean the pin of protein and other residue buildup before you start an assay.  We also tell you how to use sonication and brushes to clean the pins.  To quickly and efficiently remove the previous transfer from the pin we have several different wash reservoirs, flowing reservoirs and fountains to clean  96, 384 and 1536 floating pin tools.  These robot wash stations also are adapted so the blotting station is part of the washing station thus reducing the cleaning cycle time and the number of robot stations required for the cleaning process.  We also have other independent blotting stations (VP 540D)

Integral to the cleaning process of all pins is the blotting step between baths.  Lint particles in the slots or on pin tips, from standard paper towels, will interfere with the loading and unloading of liquid.  We have solved this problem.  The VP 540DB blotting system is a tray with the standard microplate foot print that contains a super absorbent polypropylene pad covered by a Lint Free Blotting Paper.  We strongly recommend that you use this or our other lint free blotting systems.


  Solid Pins


By simply dipping a solid pin into a liquid and removing it, you get a very uniform droplet of liquid that hangs on the tip of the pin.  This droplet is very uniform in volume.  Its size depends on several factors:


 1. Pin Diameter

 2. Surface tension of the liquid being transferred

 3. Surface tension of the pin

 4. Speed of removal of pin from source liquid

 5. Speed of pin striking recipient dry plate

 6. Depth to which the pin is submerged in source plate

 7. Depth to which the pin is submerged in recipient plate

 8. Volume of slot in pin

 9. Surface tension of the dry plate and dwell time

10. Size of the well (24, 48, 96, 384 or 1,536)

If all these factors remain the same, the volume transferred will be very precise.  Thus for applications where you are just transferring the hanging drop to a membrane or microplate,  you can get accurate and precise delivery of liquid.  If the delivery is to another liquid, then the sides of the pins which also collect liquid droplets will be added to the delivery.  In addition, the total volume transferred in liquid to liquid transfers is also dependant upon how far the pins are submerged in both the mother wells and the daughter wells.  As long as the pin transfer is done in a consistent manner you will achieve very good CV's.  If you are transferring the hanging drop to a dry well then the speed of the pin striking the surface is a factor in how much gets transferred as well as the surface tension of the dry well.  As a general rule of thumb about 35% of the hanging drop is transferred to the dry well.  With robot controlled delivery speed good CV's are obtained.



The advantage of the solid pins is that the hanging drop provides a very accurate and precise method of transferring as little as 2 nanoliter volumes of liquid to membranes or dry microplate wells.

The following table organizes our Fixed Solid Pin Replicators according to:

  1. Volume of the hanging drop (this is an approximate value as their are a number of characteristics such as liquid surface tension that will affect the volume).

  2. Pin diameter

  3. Pin number

  4. Pin type (Fixed or Long)

  5. Catalog number

  Fixed Solid Pin Replicators


Hanging Drop

Pin Diameter

Pin # & Type

Catalog # Pin Part #
~20 nl 0.457 mm 384 Fixed VP 384VR1 P1
~20 nl 0.457 mm 1,536 Fixed VP 838 P1
~100 nl 1.19 mm 96 Fixed VP 409 P2
~100 nl 1.19 mm 384 Fixed VP 386 P2
~200 nl 1.58 mm 48 Fixed VP 480 P
~200 nl 1.58 mm 96/2 Fixed VP 408H P
~200 nl 1.58 mm 96 Fixed VP 408 P
~200 nl 1.58 mm 96 Long VP 408A PA
~200 nl 1.58 mm 384 Fixed VP 384 P
~1.5 ul 2.36 mm 96 Fixed VP 407 P12
~3 ul 3.18 mm 96 Fixed VP 407A P13
~3 ul 3.18 mm 48 Fixed VP 407AH P13
  4.75 mm     P11
Fixed pins have been press fit into an aluminum or delrin base.

Pin Tool Data And Charts

For customer pin tool data please visit this hyperlink

Detailed Assay Method:


  Floating Pins


Floating pins have several advantages.  First, the pins are all assured of touching an uneven surface such as agar, a membrane or microplate with a warped bottom which is common with polypropylene microplates.  Secondly, individual pins with different delivery volumes can be selected and arranged by the user in the Replicator to facilitate making serial dilutions in the same Replicator.  Likewise damaged pins are easily replaced.  The floating design can be used manually or also by robots where the Z control may vary. 

We have two styles of Floating Pin Replicators: The E-Clip style which is the least expensive and transports the largest volume of liquid.  The Tube style which comes in 5 different pin diameters and transports the smallest volume of liquid with very precise pitch location and absolute perpendicular vertical alignment.  The Tube style also comes in three different lengths.  The standard tube style length is 50.8 mm long with a 17 mm long exposed pin length.  This is the maximum distance that the pin will stick into the microplate well.  On some robot workstations there are height limitations and for those robot systems we made a shorter pin (FPCB series) that is 33 mm long with a 12 mm exposed pin length.   For applications using deep well microplates you need a pin with a longer exposed length to reach farther down into the wells.  The FPT series pins have pins with 30 mm exposed pin lengths to adapt to these applications.


Long pins are for use on deep well plates, they are 45 to 57 mm in length and may be slotted or solid.


Hydrophobic/Lipophobic Coating


The FP series Solid and Slot Pins are also available with a hydrophobic/lipophobic coating.  This coating prevents or reduces the amount of non-specific binding of proteins and lipids to the pins.  It will also reduce "creep" of liquid up the pin. The hydrophobic/lipophobic versions are designated  with an H in the catalog number.  They can be found on the Pin page.


  Slotted Pins


By simply cutting slots into the tips of solid pins, the slots will fill precisely, by capillary action, and then deliver that amount by capillary wicking onto a membrane or by immersion into another liquid.  Usually the volume in the slot is significantly more than the drops on the side of the pin so the precision of liquid transfer is not effected greatly in liquid to liquid transfers and not at all in liquid to membrane transfers.  One of the phenomena of slotting pins is the great reduction in the hanging drop at the tip of the pin because of the slot.  This results in the volume of liquid to be transferred, being close to the volume of the slot.  

Note that slot pins will not transfer the volume of the slot to a dry well or glass slide but can be made to deliver a larger volume than a hanging drop by causing the pin to strike the surface at a high rate of speed.  This is best achieved when controlled by a robotic system.

Because it is relatively easy for us to cut any size of slot we choose, it is simple to make custom Slot Pin Replicators.   We have several that we make and stock and they are listed below.  If you don't see what you need, call us and we will make a special one for you.

The advantage of the slot pins is that the slot provides a very accurate and precise method of transferring 10 nl and greater  volumes of liquid to membranes or to liquid in daughter wells.  They are also useful in spotting nanoliter volumes onto glass slides.



FP4 slot pins are our newest slot pins.  Although they transfer relatively large volumes (1,000 and 2,000 ul) that could be easily handled by the 1.58 mm diameter pins, they are the largest diameter slot pins that can still fit inside the wells in a 1,536 well microplate.  Thus companies that have their compound libraries in 1,536 well microplates find them very useful in High Throughput Screening assays done in the 1536 format.


The larger slot volume FP6 series floating pins cover the slot volumes from 0.5 to 5ul.


  10 and 25 ul Slot Pin Multi-Blot™ Replicators - 96 pins


These replicators were made in response to scientists that want to deliver larger inoculums (usually yeast) to an agar Omni Tray or a membrane.  To make slots that will yield the larger volumes we have to use pins of a larger diameter.   The end view of the slot is illustrated in photo to the right.  The 25 ul P11AS25 pins are 4.75 mm in diameter and the 10 ul P13S10 pins are 3.17 mm in diameter.


We can also make custom slot pins that will deliver as little as 6 nl to meet your specific needs.

Also see our 8, 12, 16 and 24 Replicator Strips with slot pins and 8, 12, 16 and 24 Floating Replicator Strips with slot pins. These are good for loading gels and making microarrays on glass slides.

The 22 mm long pins are better for loading MADGE Gels or inoculating onto an agar surface.  Both of the pins are used to make quantitative liquid to liquid transfers or liquid to membrane blots. 

Pin Tool Data And Charts

For customer pin tool data please visit this hyperlink

Detailed Assay Method:


  Fixed Manual Slot Pin Replicators

~Slot Volume Pin Diameter Pin # & Type Replicator Catalog # Pin Part #
500 nl 1.58 mm 96 Fixed VP 408S.5 PS.5
500 nl 1.58 mm 384 Fixed VP 384S.5 PS.5
1 ul 1.58 mm 96 Fixed VP 408S PS
1 ul 1.58 mm 96 long VP 408Sa PSa
1 ul 1.58 mm 384 Fixed VP 384S PS
1 ul 1.58 mm 384 long VP 384Sa PSa
2 ul 1.58 mm 96 Fixed VP 408S2 PS2
2 ul 1.58 mm 96 long VP 408S2a PS2a
2 ul 1.58 mm 384 Fixed VP 384S2 PS2
2 ul 1.58 mm 384 long VP 384S2a PS2a
5 ul 1.58 mm 96 Fixed VP 408S5 PS5
5 ul 1.58 mm 96 long VP 408S5a PS5a
5 ul 3.18 mm 96 Fixed VP 408S5L P13S5
10 ul 3.18 mm 96 Fixed VP 408S10 P13S10
25 ul 4.75 mm 48 Fixed VP 402-P11AS25 P11

  Grooved Pins


Grooves at the end of a solid pin will fill precisely by capillary action just as the slots do. Grooved pins are only used for liquid to liquid transfers. 

The advantage of grooved pins is that they provide a very accurate and precise method of transferring from  3ul to 90ul.

Some of our customers who are transferring particulates prefer the groove pins as they feel the particulates are less likely to “fall out” of a groove as they might a slot.  Whether this is true or not we don’t know as we don’t have access to their particulates.  However these customers are happy with our grooved pin replicators and continue to order them.


~Groove Volume

Pin Diameter

Pin # & Type

Catalog #

3 ul 2.77 mm 96 Fixed, 22 mm long VP 403D1
3 ul 2.77 mm 96 Fixed, 22 mm long VP 403D1a
3 ul 1.58 mm 96 Fixed, 57 mm long VP 408B
5 ul 2.77 mm 96 Fixed, 13 mm long VP 403B
5 ul 2.77 mm 96 Fixed, 22 mm long VP 403D2
6 ul 2.77 mm 96 Fixed, 47 mm long VP 403F
7 ul 3.18 mm 96 Fixed, 22 mm long VP 403A
20 ul 3.18 mm 96 Fixed, 22 mm long VP 403E
50 ul 6.35 mm 24 Fixed, 57 mm long VP 224A
90 ul 6.35 mm 24 Fixed, 57 mm long VP 224B



The threads of the bolt pick up large volumes of liquid for liquid to liquid transfers or for spotting yeast onto agar plates. The volume of liquid transfer depends upon the pitch and depth of the threads and the depth to which the threads are submerged in the mother and daughter wells.  The Bolt Type Replicators are used where precision of transfer is not important. 

Their advantage is that they are inexpensive and transfer larger volumes.

We do not recommend these replicators for transferring to membranes or agar surfaces as the height of the bolts vary considerably from bolt to bolt.


  Bolt Type

~Thread Volume Bolt Specifications Bolt # & Length Catalog #
10 ul 8-32 96, 18 mm long VP 404
10 ul 6-32 48, 17 mm long VP 404A
20 ul 10-24 96, 17 mm long VP 405
50 ul 8-32 96, 53 mm long VP 404B

  Replicator Strips


We also provide many of the same pins as Replicator Strips (a single row or column of 8, 12, 16 or 24 pins arranged in 96 or 384 well format - 9 mm or 4.5 mm centers).


  Glass Slide Replicators


We also provide some of the same pins in 2 and 4 row strips for spotting DNA onto glass slides in high density arrays. Glass Slide Replicators for 96 well microplates and 384 well microplates are found on the Glass Slide Arrayer page.


  Factors Affecting Pin Delivery Volumes


The list on the right summarizes the factors that contribute to the volume delivered.  With each application these factors can be controlled and standardized so that the delivery volumes are very reproducible.  With most robot applications the CV are less than 5%.

Probably the most useful factor is that by robotically changing the speed of withdrawal from the source plate you can precisely determine the volume of liquid on the pin over a large dynamic range.  This range is illustrated in the table below.

 1. Pin Diameter
 2. Surface tension of the liquid being transferred
 3. Surface tension of the pin
 4. Speed of removal of pin from source liquid
 5. Speed of pin striking recipient dry plate
 6. Depth to which the pin is submerged in source plate
 7. Depth to which the pin is submerged in recipient plate
 8. Volume of slot in pin
 9. Surface tension of the dry plate and dwell time
10. Size of the well (24, 48, 96, 384 or 1,536)

  Select The Volume You Need To Transfer For Your Application


Delivery Volume Ranges


Delivery volume range is determined by speed of withdrawal from source liquid.
slow speed  = 0.78 cm/sec = low volume delivery range
fast speed  =  5.70 cm/sec = high volume delivery range
Follow this link to assay methods


The links below are to delivery volume range tables for uncoated and hydrophobic coated delivering either DMSO or Aqueous solutions in liquid to liquid transfers.





  A Guide For Selecting The Right Pin For Your Application


1.  What volume do you need to  transfer?   DMSO? Aqueous? See these hyperlinked tables to determine your options.  Also consider custom slot pins.

2. Will the source plate have wells with significantly different levels of liquid?  (Cherry picked source plate or edge drying effect?).  If yes and if the absolute volume transferred is critical, then select the largest slot pin that is in your transfer range.  This will minimize the effect of liquid height on the volume of liquid carried on the sides of the pin.  Also consider custom slot pins.

3. Does the material transferred bind non-specifically to stainless steel?  If yes then select the Hydrophobic/lipophobic coated pins.  If no, select the uncoated pins.

4.  What is the Z clearance on the robot deck from the highest impediment (top of the source plate/recipient plate/wash reservoirs, etc.) to the top of the robot mounting plate?  If it is greater than 77 mm you can use any of pins.  If it is less than 77 mm, you can only use the shorter FP(#)C series pins (12 mm exposed pin length), the FP(#N) series pins (17 mm exposed pin length) and the E-clip series pins (23 mm exposed pin length pins.  If the Z clearance is less than 60 mm, we recommend you contact us.  There are a few tricks we can do to shave off 5 to 10 mm in height. 

Links to the specifications of all the robot mounting plates/pin tool/pin combinations can be found on the height ("Z") restriction page

5.  Is the source plate a deep well plate?  If so you may need to use a 30 mm long exposed length pin ("T" pin) to reach down to the lower levels of the well. 

6.  Should you choose the solid pin versus the slot pin? Although the there appears to be a slight advantage for slot pin, CV's between the two pins are very good.  Both are easy to clean between specimens.  Biggest factor is cost.  If you don't need to deal with varying liquid heights and you can obtain the volume necessary with a solid pin, choose the economical solid pin.

7.    If you are still uncertain about which pin to select for your application, you can perform a simple "Proof of Principle" test with several different pins using our inexpensive VP 450FP3 Replicator Strip coupled via a VP 452MP to one of our robot mounting plates.   An even simpler solution is to use a work station with a 1, 4 or 8 probe dispense head with the new V&P Mono Pin Tool to test the various pins.


  Liquid To Dry Plate Transfers For Multiplexing Assays


Many of our customers want to make liquid to dry plate transfers to make mini-microarrays in a single well for multiplexing assays.  By their very nature these transfers only leave a small volume remaining on the plate.  The amount remaining depends on the surface tension of the plate, the transfer liquid and the pin (diameter and shape).  We have found that reasonable results can be obtained if you use an aqueous spotting buffer and a polypropylene surface (CV's less than 9%).  DMSO spotting buffers leave much less liquid on the dry plate and when used with polystyrene plates the CV's are significantly higher. 


The plate to the right was spotted using a 50 nl slot pin (FP1CS50) transferring oligo DNA in an aqueous spotting buffer to a specially treated polypropylene plate.  Our customer in this case wanted to place 42 individual spots in the bottom of each well of a 96 well microplate.  Spot diameter = 0.55 mm. Volume transferred to the spot = 5.85 nl


The photo on the right is the result of a four fold serial dilution hybridization assay of the Oligo spots with a labeled DNA that can be detected optically and quantitated.


Follow this link for more information on liquid to dry transfers and Multiplexing.



  Defining A Pin Tool


Originally we sold our pin tools with unique part numbers.  As we have added more pins to our selection and more robot systems to mount the pin tools to, the number of unique part numbers grew exponentially to an un-manageable size.  Our solution has been to specify a pin tool by the 3 component parts that compromise the Pin Tool.  The Pins, the Floating Fixture and the Robot Mounting Plate.  If you have previously ordered a pin tool by unique part number, we will be able to provide the same pin tool to you.


  Selecting a Pin Tool as Simple as 1, 2, 3


1. Select the appropriate pin.  For the manual and Beckman Bio Mek 2000 robots we recommend the longer FP(#) series pins.

2. Select the Floating Fixture with the appropriate pattern (96, 384 or 1,536) and diameter of holes.


3. Select the robot system you wish to use the Pin Tool with.  We have made Mounting Plates to over 34 Robot Workstations. 

Determine the weight of a Robot pin tool at this link


  Convert A Robot Pin Tool To A Manual Pin Tool


Our Robotic floating Pin Tools can easily be converted to a manual pin tool with this simple BGPK  kit which contains a Guide Pin Frame and handle and sturdy mounting plate (BMPM)  The guide pins are used with our manual microplate (VP 381N) and membrane registration accessories (VP 382 and VP 382B) to keep the pins in the center of the wells and to make high density arrays on membranes or agar surfaces.

Conversion of robot pin tools to manual Multi-Blot Replicators is very easy using our BGPK for Standard length pins and the BGPKL for longer pins.  Simply remove the robot mounting feature from the float plates disassemble the pin tool and reassemble it with the Guide Pin Frame as part of the tool.  Attach the Manual Mounting Plate and handle and you are ready to go.   If this sounds too daunting for you - send it back to us and we will do it for you for a nominal fee.


The main reason for this conversion is to attach  guide pins to the replicator so it can be aligned to Microplate registration accessories such as the VP 381 series Library copiers for replicating and reformatting genomic libraries, VP 380 series colony copiers to make high density arrays on agar surfaces or  VP 382 membrane printers to make high density arrays on nylon or other membranes.

The BGPKL kit is used when longer replicator pins are used like the FPAM pins which are 63 mm long.   A pin tool with FPAM pins is illustrated in the photo to the right.   In order to accommodate these longer pins we need to use a longer and more sturdy guide pin found on the BGPL frame.  These larger guide pins are 3.17 mm in diameter.

Each of the kits on the right (BGPKL and BGPK) is made up of a handle, a manual mounting plate and a guide pin frame.  The guide pin frame is the only  difference between the two kits


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