The Scientist
     March 2, 1998


  Miniaturized Mixing: V&P Scientific's Tumble Stirrer



LabConsumer ventured to LabAutomation '98 (January 19) in San Diego, California, with the intent of finding a truly unique piece of laboratory equipment. After hours of searching, we stumbled upon V&P's Alligator Microplate Magnetic Tumble Stirrer. V&P Scientific has developed the Alligator Tumble Stirrer (patent pending) as a simple and efficient method for stirring microplates. As opposed to using a spinning magnetic stirring bar, the Alligator Tumble Stirrer causes stirrers to tumble end over end inside each well, similar to the way alligators "tumble" their prey.


The Alligator, which has been on the market about two years, can handle all microplate formats (24- to 1,536-well plates), deep-well plates, V- and U-bottom microplates, PCR plates, microfuge tubes, test tubes, and bottles. The Alligator measures a mere 17 inches wide by 17 inches deep by 7 inches high and can fit inside most incubators. The VP 709A can stir four layers of nine microplates (36 microplates total).


The Alligator has numerous applications, but according to V&P Scientific President Patrick Cleveland, "The most prominent application of the Alligator has been stirring genomic libraries as they are growing." Other applications include stimulating the growth of aerobic organisms, suspending microorganisms, breaking up filamentous organisms, dissolving solids, mixing two or more compounds, mixing oil and water emulsions, scraping tissue culture monolayers and releasing DNA, and mixing and immobilizing reactions that use magnetic beads.


Does the thought of filling all 384 wells of a microplate with stirrers make you cringe? V&P Scientific has also developed a simple and efficient method of placing sterile stir bars, dowels, and discs into microplates with liquid already in them. Users simply pour bulk stirring bars, dowels, or discs into the appropriate stirrer dispenser, gently shake the dispenser until each of the holes is filled, pour off excess stirrers, place the dispenser over the microplate, and dispense (drop) stirrers into the wells. These dispensers can be disinfected with bleach or alcohol, and others can be autoclaved.


Especially useful for high-capacity plates or for stirring solutions with magnetic beads, V&P offers a magnet powder with 0.7 mm diameter particles that come together in the presence of a strong magnetic field to form multiple magnetic stalactites in the bottom of the microplate wells. The tumbling action of the stalactites on the Magnetic Tumble Stirrer provides efficient yet gentle stirring of the liquid. The tumble powder is added to wells as a liquid slurry.


For more information contact V&P Scientific at 800-455-0644 or


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