Molecular Devices

As the trend towards assay miniaturization continues with increasing demands to make nanoliter transfers, here is a simple way to convert a FLIPR^TETRA_TM into a 384 or 1,536 pin tool for UHTS.

The FLIPR^TETRA system from Molecular Devices delivers an entirely new screening platform to address the real-time kinetic cell-based assays. This instrument broadens the FLIPR^TETRAsystem's capabilities to include 1536 simultaneous liquid transfer, multi-wavelength kinetic reading and agile internal plate handling, in addition to elevated instrument intelligence. Combined, these features enable users to save time and money, while addressing their preferred screening targets.

In particular, Molecular Devices' FLIPR^TETRA1536 pin tool liquid transfer technology significantly reduces screening time and reagent consumption. Simultaneous liquid transfer to approximately 2,000 cells per well in a 1536-well plate is achieved using a 1536 pin tool. Contact liquid transfer occurs with the same height, speed and a range of delivery volumes from 19 nL to 656 nL.

FLIPR^TETRA using pins from V&P Scientific, allows direct transfer of compounds that have been suspended in 100% DMSO or ethanol. The transfer of compounds in nanoliter volumes (as low as 19 nL {or lower on a custom pin}) eliminates the need for an intermediate dilution plate to decrease DMSO concentration. Because transfer volumes are small, DMSO concentrations are 1% or less, and toxic effects to the cells are minimized. In addition, by transferring compounds directly from the library to the read plated, consumable costs, including plates and tips, are significantly decreased, minimizing assay preparation time and increasing throughput.

The pin tool also allows non-specific or "sticky" compounds to transfer easily using the optional hydrophobic-lipophobic pin coating. Because the compounds do not stick to the pins, accurate dispensing of compounds is achieved.

FLIPR^TETRA provides user-configurable fluidic components to enable you to exchange pin tools with traditional pipettors in less than 10 minutes. Pin tools are available for different liquid volumes in 384 and 1536-well formats.

ScreenWorks^TM software makes it easy to transition between pin tools and adjust transfer volume. ScreenWorks also enables you to customize pin washing using up to two solvents, as well as automate the use and exchange of disposable blotting stations.

Cleaning The Pins

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 and virtually identical results were obtained, indicating the thoroughness of the wash.

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

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 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.

Select The Volume You Need To Transfer For Your Application

DMSO Liquid To Liquid Transfers With Uncoated Pins

PIN	DIAMETER	SHAPE	*DELIVERY VOLUME RANGE#**
FP1N	0.457 mm	solid	19 – 68 nl
FP1NS6	0.457 mm	6 nl slot	26 – 74 nl
FP1NS10	0.457 mm	10 nl slot	31 – 79 nl
FP1NS20	0.457 mm	20 nl slot	43 – 89 nl
FP1NS30	0.457 mm	30 nl slot	53 – 99 nl
FP1NS40	0.457 mm	40 nl slot	64 – 109 nl
FP1NS50	0.457 mm	50 nl slot	74 – 117 nl
FP3N	0.787 mm	solid	84 – 240 nl
FP3NS100	0.787 mm	100 nl slot	178 – 326 nl
FP3NS200	0.787 mm	200 nl slot	278 – 424 nl
FP3NS500	0.787 mm	500 nl slot	527 – 656 nl

*# 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.

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

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? We recommend the 17 mm exposed length FP(#)N series pins for most applications however you can also use the shorter FP(#)C series pins (12 mm exposed pin length pins.

5. 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.

6. 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.

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.

Ordering Your Pin Tool As Simple As 1, 2, 3

A Molecular Devices pin tool consists of two separate parts.

1. The pins, (#FPN)
2. The Floating Frame Fixture (384 or 1536) (#AFIX___FP_MD)

For example the part numbers for pin tool in the photo to the right would be FP1N, AFIX384FP1MD

To order, just tell us those 2 part numbers and we will assemble your Pin Tool.

1. Choose The Pin

1. Choose the pin to match your application, pin length, delivery volume requirements and/or the non-specific binding nature of the sample.

Solid Pins

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

Solid pins for Molecular Devices are available in 2 exposed pin lengths; 12 and17mm. The 12 mm ("C") pins are used with a 1536 and the 17 mm ("N") pins are used when transferring from a 384 or 1536.

Slot Pins

Slot pins have several advantages over solid pins:

Slot pins carry a larger volume than solid pins in liquid to liquid transfers.
Slot pins are not as sensitive to the depth of the mother liquid as solid pens.
Slot pins deliver a larger volume than solid pins in liquid to dry plate transfers.
Slot pins deliver a larger volume than solid pins in liquid to membrane transfers.
Slot volume is customizable.
Slot pins can deliver to dry plates by pre-wetting the plate.

**NEW** Hydrophobic/Lipophobic Coated Pins

Hydrophobic/lipophobic coated pins are very useful in handling solutions with proteins or lipids that may stick to naked stainless steel. Both solid and slot pins can be coated. Click here for more details on the nature of our hydrophobic/ lipophobic coating and the coating process.

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

Tube Style Pins

Uncoated
12 mm/33 mm length - solid pins	17 mm/38 mm length solid pins	17 mm/50 mm length solid pins	30 mm/50 mm length solid pins
12 mm/33 mm length slot pins	17 mm/38 mm length slot pins	17 mm/50 mm length slot pins	30 mm /50 mm length slot pins

Hydrophobic coated
12 mm/33 mm length solid pins	17 mm/38 mm length solid pins	17 mm/50 mm length solid pins	30 mm/50 mm length solid pins
12 mm/33 mm length slot pins	17 mm/38 mm length slot pins	17 mm/50 mm length slot pins	30 mm/50 mm length slot pins

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

2. Choose The Floating Fixture

2. Choose the Floating Fixture to match your application. Standard are 384 and 1,536 formats.

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 .457 mm or .787 mm 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 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.

Call Molecular Devices for pricing information and tell them the part numbers you need for the pin tool -

Pin # (FPN)
Floating Frame Fixture # (AFIX__FP__ MD)

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

Custom Floating Slot Pin Replicators

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 1000 nl by changing the width and depth of the slot. Inquire by phone or e-mail for more information.

Cleaning Pins On A Molecular Devices Mounted Pin Tool

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 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.

Pin Tool Accessory Kit

We highly recommend that you order the Pin Tool Accessory kit at the time you order the pin tool. This "essentials" accessory kit contains the 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. 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.

Pin Tool Accessory Kit - VP OK22
Pin Tool Docking Station for "hot swapping" (1)	VP 550
Lint Free Blotting System with pad (1)	VP 540DB
Pin Wash Reservoirs (2)	VP 540
Pin Cleaning Solution (1)	VP 110
Pin Cleaning Brush (1)	VP 425