We offer a variety of different diameter stainless steel corrosion resistant magnetic levitation balls which have been tested and selected on the basis of maximum magnetic characteristics, cleaned and degreased. We recommend the 2.38 mm diameter balls for the Polyfiltronics (now Whatman) 384 deep well microplates (VP 725), 3.97 mm diameter balls (VP 725E) for round 96 deep well microplates and 4.76 mm diameter balls (VP 725F) for the larger square 96 deep well microplates. We can provide balls of other diameters to function with your particular needs on a custom basis.  The VP 725G and VP 725G-2 are examples of larger diameter (5.56 and 5.57 mm diameter) custom balls we have provided customers.  The VP 725G-2 are custom PTFE dipped and baked balls. 

The above balls are also available with a parylene coat  ~50 microns thick -VP 725-1, VP 725E-1, VP 725F-1) to prevent metal ions from entering the reaction mixture.  Parylene is an inert plastic polymer similar to teflon.   This is especially useful for those applications (combinatorial chemistry) where Fe molecules may interfere with the reaction, or the stirrers would be attacked by strong acids or bases.  Parylene (Di-Para-Xylene) is deposited on the surface of the stirrer in a very uniform 0.05 mm thick layer, thus protecting the stirrers from strong acids and bases.  Parylene coated stirrers can be autoclaved or sterilized in hot air ovens without harming the conformal coating.  Parylene can be heated to 200°C without harming the surface.  Parylene is also compatible with biological applications.  In fact, parylene is used to coat materials for implant procedures, as it is completely non-toxic to tissues.  A very complete discussion of parylene's barrier characteristics, properties and methods of deposition is found at this hyperlink.  Another page is dedicated to parylene's resistance to organic solvents, acids and bases.

Parylene Coated Balls (all VP part numbers that are followed by a "-1" represent the parylene coated version of that ball)

Sterile Balls (all VP part numbers that are followed by a "S" represent a sterile version of that ball)

The balls are priced low enough to be disposable, however they can be reclaimed, cleaned, autoclaved and then reused.  Recycled Levitation Stir Balls - 2.38mm diameter, for 384 deep well plates, sterile, 50,000/bottle.....VP 725RS

All of the above balls come in quantities of 1000, but are also provided in sterile quantities of 10,000 and stored in pyrex bottles (VP 725S, VP 725-1S, VP 725FS, VP 725E-1S, VP 725FS, VP 725F-1).

Click here for a list of published articles that cite the products on this page.

Autoclaveable Flip Dispensers

Flip dispensers to load the balls into each of the deep well microplates are available. These dispensers are easily filled by pouring an excess of balls into the dispenser, rocking it several times to fill the holes and pouring off the excess balls.  Next, an empty microplate is placed on top of the dispenser and the dispenser and the microplate are "flipped" over and the balls drop into the microplate wells. 

Flip loads the VP 725, VP 725S, VP 725-1 and VP 725-1S Levitation Balls into 384 deep well microplates.....VP 725B

Flip loads the VP 725E, VP 725ES, VP 725E-1 and VP 725E-1S Levitation Balls into 96 deep well microplates.....VP 725EB

Flip loads the VP 725F, VP 725FS, VP 725F-1, VP 725F-1S, VP 725G aand VP 725G-2  Levitation Balls into 96 deep well microplates.....VP 725FB

Plastic Drop Dispensers

Drop Dispensers To Load The Levitation Balls Into 96 And 384 Deep Well Microplates

Drop loads the VP 725, VP 725S, VP 725-1 and VP 725-1S Levitation Balls into 384 deep well microplates.....VP 725A

Drop loads the VP 725, VP 725S, VP 725-1 and VP 725-1S Levitation Balls into 96 deep well microplates.....VP 725A-1-96

Drop loads the VP 725E, VP 725ES, VP 725E-1 and VP 725E-1S Levitation Balls into 96 deep well microplates.....VP 725EA

Drop loads the VP 725F, VP 725FS, VP 725F-1 and VP 725F-1S Levitation Balls into 96 deep well microplates.....VP 725FA 
 

Autoclaveable Drop Dispensers - Series D

New Autoclaveable Drop Dispensers (VP 725D & VP 725FD) can drop load the balls into each of the deep well microplates.  These dispensers are made from aluminum and have a ball hopper that holds extra balls.  The ball hopper feature has the advantage of filling 5 microplates before the hopper has to be reloaded with balls.  This capability significantly speeds the loading process.  In addition to these advantages, drop loading of sterile balls is an essential process in many stirring procedures.

Drop loads the VP 725, VP 725S, VP 725-1 and VP 725S-1 Levitation Balls into 384 deep well microplates.....VP 725D

Drop loads the VP 725E, VP 725ES,  VP 725E-1, VP 725E-1S, VP 725F, VP 725FS, VP 725F-1 and VP 725F-1S Levitation Balls into 96 deep well microplates.....VP 725FD

Click here to watch a video of how to use our autoclaveable drop dispensers.
 

Choice Of Dispenser

The choice to use Flip, Plastic Drop or Aluminum Drop Dispensers is determined by three factors:

1. Cost
2. Sterility
3. When the stir ball can be added to the plate

Some stirring processes/protocols dictate that the balls can only be added after liquid is added to the wells. In those cases the drop dispensers must be used. 

If the process is done sterilely than either the Flip Dispensers or the Aluminum Drop Dispensers must be used. 

The Flip Dispensers are less expensive but they can only be used to place the balls in the wells when there is no liquid in the wells.  The Flip Dispenser operates by filling the depressions in the dispenser with balls, then placing a deep well plate upside down on the dispenser and "flipping" the dispenser over allowing the balls to fall into the wells.  Whereas a Drop Dispenser can "drop" the balls into wells that already contain liquid. 

The Plastic Drop Dispensers cannot be autoclaved but they can be disinfected with bleach and or ETOH.  They are less expensive than the Aluminum Drop Dispensers. 

The Aluminum Drop Dispensers can be sterilized by autoclave or in a hot air oven.  They also have the advantage of a levitation ball hopper that will hold enough balls to fill 5 microplates thus facilitating the loading process.

VP 725C

The latest in the line of Ball Drop Dispensers is the Semi Automatic Levitation Ball Loader (VP 725C). The Semi Automatic Levitation Ball Loader can fill 400 microplates with sterile balls in an hour.  All you need is an operator to feed the microplates to the loader.  With the push of a button, in 7 seconds the microplate is loaded with sterile levitation balls using a system of pneumatic cylinders. This system is ideal for laboratories that wish to mix large numbers of microplates. 

The Semi Automatic Levitation Ball Loader comes in three models to dispense all three sizes of Levitation Balls, 2.38 mm (VP 725C), 3.97 mm (VP 725EC) and 4.76 mm (VP 725FC).

Download Video of VP 725C in action
(mpeg movie- 1.1MB)

Press the play button to view the video in a flash format, flash must be installed, or click the download link to download a mpeg version.

VP 725C-96

Download Video of VP 725C-96 in action
(mpeg movie- 16.5MB)

Press the play button to view the video in a flash format, flash must be installed, or click the download link to download a mpeg version.