As the trend towards assay miniaturization continues with increasing demands to make nanoliter transfers, here is a simple way to convert an OASIS Liquid Handling System into a 96, 384 or 1,536 pin tool work station that will deliver from 2 nl to 5 ul.  The pin tools are attached directly to robot.

SAVE MONEY

Pin tools will save you money.  Not only will you use less of your valuable lead compounds,  you will also pay for the pin tool in your second screening operation by eliminating the cost of disposable pipet tips.  At $.12/tip, 200 cases of 384 tips are ~$9,000.00

Cleaning the Pins

Clean pins are the key to successful nanoliter transfers.  We have developed simple yet effective methods for starting with and maintaining clean pins in HTS applications.  Procedures for transferring liquids, robot speed, wash solutions, blotting protocols and pin cleaning can found at this hyperlink.  Cleaning the pins between mother plates is easy and effective.  In an experiment to determine the amount of carry over after 100 transfers of concentrated FITC (mother to daughter plate) we were only able to detect  0.000,001,8% of the residual FITC on the pin using only two static 100 ml wash baths.  To put this into perspective, it is equivalent to removing all but 18 molecules out of a possible 1,000,000,000 molecules. This experiment was repeated using DMSO as the first wash solution.  Virtually identical results were obtained, indicating the thoroughness of the wash.

For comprehensive data on nanoliter dispensing with pin tools see the following pages.
 

• DMSO and Aqueous delivery with hydrophobic coated and uncoated solid and slot pins

• DMSO and Aqueous delivery with solid and slot pins

• Maxim Pharmaceuticals, results with slot pin tools

• New England LRIG presentation 6/18/02

• Pin tool data page

The list on below 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 applications the CV's are less than 5%.

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 

V&P pins transfer liquid by carrying the liquid on the sides, tips and in slots we cut into the tips. The amount delivered is determined by the diameter and surface tension of the pin, the surface tension of the liquid, how far the pin is submerged into the liquid and the speed with which the pin is removed from the liquid.  When all of these variables are fixed, the accuracy of the liquid transfer is very consistent, with CV averages better than 5%.

Increasing the speed of withdrawal from the source plate by 7- fold will increase the volume delivered by as much as 3 fold in a linear relationship.  This phenomenon can be exploited to expand the range of delivery volume for a single pin. The table and the chart below illustrates the effects of increasing the speed 7- fold.  The speed range is from 0.78 cm/sec to 5.7 cm/sec.  Use this chart to select the pin that will deliver in your desired range. 

DMSO Liquid To Liquid Transfers With Uncoated Pins

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

DMSO TRANSFERS WITH HYDROPHOBIC COATED PINS

DMSO TRANSFERS WITH UNCOATED (STAINLESS STEEL) PINS

AQUEOUS TRANSFERS WITH HYDROPHOBIC COATED PINS

AQUEOUS TRANSFERS WITH UNCOATED (STAINLESS STEEL) PINS

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 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.

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.

A pin tool consists of three separate parts:

1.  The pins, (#FP___)
2.  The Floating Frame Fixture (96, 384 or 1536) (#AFIX___FP_)
3.  The mounting plate that attaches the Floating Frame Fixture to the Dynamic Devices OASIS (#BMPN)

For example the part numbers for pin tool in the photo to the right would be FP1, AFIX1536FP1 and BMPN.

To order, just tell us those 3 part numbers and we will assemble your Pin Tool.

Determine the weight of a Robot pin tool at this link

Solid Pins

Solid pins are the most economical and control volume transferred by pin diameter.

Slot Pins

Slot pins have several advantages over solid pins:

1. Slot pins carry a larger volume than solid pins in liquid to liquid transfers.

2. Slot pins are not as sensitive to the depth of the mother liquid as solid pens.

3. Slot pins deliver a larger volume than solid pins in liquid to dry plate transfers.

4. Slot pins deliver a larger volume than solid pins in liquid to membrane transfers.

5. Slot volume is customizable.

6. Slot pins can deliver to dry plates by pre-wetting the plate. 

Hydrophobic/Lipophobic Coated Pins

The tables below contain hyperlinks to the various types/lengths/diameters/coatings of the pins we offer.

Tube Style Pins

Floating E-Clip Style

• Flat tip solid pins

• Flat tip slot pins

• Pointed tip solid pins

• Pointed tip slot pins

Please visit this hyperlink for Pin Tool Data And Charts on hydrophobic pins.

These floating fixtures consist of an upper float plate that will all accommodate a 1.58 mm diameter tube, a lower float plate that will accommodate either a .229 mm (FP9), .457 mm (FP1) or .787 mm (FP3) diameter pin and 6 standoffs that keep the two plates separate.  The length of the standoffs is determined by the length of the pin used.  Your application will determine if you select the 96, 384 or 1,536 formats and your previously made pin selection will determine the diameter of holes in the lower float plate.  Click here for a complete selection of these floating fixtures..

 If you have more specific needs call us for help at (800) 455-0644.

Combine the number and type of Pins with the Floating Frame Fixture selected and the Basic Mounting Plate for the Dynamic Devices OASIS (BMPN) and you have a complete pin tool. 

Call Dynamic Devices  for pricing information at (508)544-7000 and tell them the part numbers you need for the pin tool - Pin # (FP___)
Floating Frame Fixture # (AFIX__FP__ )
Mounting Plate # (BMPN).

Replacement Pin Link for the Tube style Dynamic Devices Pin Tools.

The Double Float Plate Dynamic Devices OASIS Tube Style Pin Tools have several advantages over the E-Clip Style Pin Tools:

1. The Tube Style Pin Tools are smaller in diameter and deliver very small volumes (down to 2 nl and as much as 500 nl depending on diameter and slot size).

2. Smaller pin diameters also result in more precise delivery volumes (CV's ~4%).

3. Because the pin is registered between 2 float plates over a greater height, the pin angle will be truer (closer to 90^°) when they touch the surface. 

4. The smaller hole on the lower float plate allows us to make very tight tolerances on the fit between the pin and the hole.  This results in very precise placement of the pins on the surface so that very high density arrays can be made without overlapping the spots.

The E-Clip Pin Tools on the other hand are capable of delivering larger volumes (from 0.5 to 5 ul).

Custom Floating Slot Pin Replicators can also be made using the 0.457 mm and 0.787 mm diameter pins and placing them into the Floating Pin Replicators described above.  The slot volumes between these two pins can cover a range of volumes from 5 nl to 2000 nl by changing the width and depth of the slot.  Inquire by phone or e-mail for more information.

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.  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 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.

Storage Stations for Pin Tools offer a safe place to store pin tools and keep them clean and out of harms way.

We highly recommend that you order the Dynamic Devices Pin Tool Accessory kit at the time you order the pin tool.  This "essentials" accessory kit contains the VP 550 Docking Station for the Pin Tool on the robot deck giving you the capability for "Hot Swapping" the pin tool for other accessories, The VP 540DB Lint Free Blotting System is used to clean the pins efficiently between samples, two VP 540 Wash Reservoirs to wash the pins between source plates, the VP 110 Pin Cleaning Solution is used the clean the pins daily, the VP 425 Pin Cleaning Brush is used if a build up occurs and the VP 555 Safe Pin Tool Storage System used to keep it clean and the fragile pins out of harms way.   Although we have several other wash and blot accessories available these are the most cost effective for the majority of applications.  If you elect to use the fountain and flowing reservoirs we still strongly recommend the other items in this kit.  When purchased as the VP OK18 Kit you will receive a 5% discount over the sum of the individual items.

FLAT TIP SLOTTED E-CLIP PINS

Our new FP6 slotted flat tip E-Clip pins are the pins of choice for transferring liquids to agar or other soft surfaces and melting/transferring frozen stocks while replicating genomic/microbial libraries.

POINTED TIP SLOTTED E-CLIP PINS

Our pointed tip FP series slotted E-Clip pins are used to remove samples from the tips of conical wells of source plates.  Because of the sharp point they are not recommended for spotting on agar or other soft surfaces.