Trends & Perspectives

Published: May 1, 2008
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Tube rotator wins medical design award for IVDs

By: Beth W. Orenstein






The task seemed simple: design a rotator that would allow technicians and researchers to more easily mix biological samples in test tubes at different levels of agitation, from a gentle roll to a vigorous tumble.

But it really came with quite a few challenges. The rotator had to take up minimal space in the often crowded laboratory. The user had to be able to easily change mixing levels without the use of additional tools. The unit had to be lightweight so that it could be moved without difficulty. And it had to be easy to store and to clean. Also, the product had to be able to be manufactured and assembled in the United States at a reasonable cost.

Pensa (Brooklyn, NY), a strategic design company, met all the challenges and more with its Tube Rotator for Labnet International Inc. (Edison, NJ), which manufactures laboratory equipment and supplies for bioscience and bioresearch.

The result is a product that is not only selling well but that also has won a Medical Design Excellence Award (MDEA) in the in vitro diagnostics category. The award will be presented June 4 during the Medical Design & Manufacturing East 2008 Conference and Exposition at the Jacob K. Javits Convention Center in New York City.

Sponsored by Canon Communications, MDEA is the premier awards program for the medical technology community. Winning entries excel in the areas of product innovation, design and engineering achievement, end-user benefit, and cost-effectiveness in manufacturing and healthcare delivery.

However, it was not only the rotator's attractive design that disting­uishes it from functionally similar, but generally bland devices that earned the product a prestigious MDEA. The product also makes significant im­provements to the rotator's performance.

Pensa's Marco Perry, a mechanical engineer, and Jim Best, a product designer, began the project by visiting different laboratories and asking users what they wanted in a rotator. Their interviews revealed the need for rotator equipment that was very easy to use from storage to use to cleanup, Perry says.

To meet the technicians' needs, they developed a split winged assembly with two plates for the vials. The individual wings easily snap off and are interchangeable.

“The technician can mix and match plates so that the rotator can simultaneously mix [as many as] three different vial diameters, making testing more efficient,” Best says.

Most standard rotator models use large, expensive motors with complicated speed controls to adjust agitation. With the Labnet rotator, the technician simply adjusts the plates to achieve the desired level of agitation.

For example, if the technician moves the rotisserie plate perpendicular to the axle, it places the sample tubes in a horizontal position. Rotation in this configuration produces a gentle mixing motion such as that required for hybridization.

Turning the plate so that it is parallel to the axle produces an end-over-end tumbling motion, such as required for mixing samples in blood tubes. The plates can be adjusted to any level between these extremes to produce the desired level of agitation.

The designers' interviews also revealed that tube rotators often take up precious work surface in a crowded laboratory environment. So they opted for a small footprint for the rotator—9.5 ¥ 5 ¥ 6 in.—and weight of only 4.5 lb for easy transport from the bench to a cold room, incubator, or biological hood. They added a molded handle to make it even easier to move the mixer if necessary.

Yet another concern was designing a competitive product that would be manufactured in the United States, where labor costs are high. “To keep costs down, we tried to keep parts and assembly to a minimum,” Best says.

In the end, the designers chose a molded housing and parts that could be quickly assembled in few steps. Still, the tooling was complicated and required tight tolerances to get the friction-fit parts to work perfectly, says Michael Rosenblum, marketing vice president for Labnet.

The designers also purposely chose molded plastic materials that could be easily cleaned and decontaminated for a sterile laboratory environment and that would not corrode like those made of metal will over time.

Additional information about the MDEA competition can be accessed via its Web site at


Copyright ©2008 IVD Technology


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