“Incubated/refrigerated shakers are more versatile than open-air orbital shakers,” says As Santanu Das from technical product support at VWR International (Radnor, PA). “They offer a wide variety of temperature options including ambient, incubation, and refrigeration.” The breadth of experiments and applications that require shaking need this range of temperatures.
As Rick Passanisi, senior product manager at Eppendorf (Enfield, CT), says, “Temperaturecontrolled shakers are primarily used to culture various cell types, including but not limited to bacteria, insects, yeast, algae, and plant and mammalian cells.” He adds, “Orbital shakers operate at a wide variety of temperatures and speeds, creating the optimal environment for the particular cell line that they are growing.” The reason for shaking the cells is to get more oxygen to the cell lines, and actually give them just the right amount that they need to grow at their optimal rate.
An eccentric option
In some applications, biologists shake particular cells in very specific ways. As an example, Passanisi says, “The New Brunswick S41i was developed to provide the mammalian cell market with a product that shakes and incubates in a regulated CO2 environment.”
This temperature-controlled shaker provides a variety of key features. For one thing, says Passanisi, a “triple eccentric drive mounted outside of the chamber provides vibration-free shaking without affecting the internal environment.” In addition, the user selects a specific temperature, speed, and CO2 concentration to create the desired environmental conditions for the cells.
Like other chambers used for growing cells, incubator shakers need to be kept clean. The New Brunswick S41i’s high-temperature decontamination, says Passanisi, allows the customer to “decontaminate the inside chamber, eliminating the possibility of cross contamination occurring.” He also points out that the “seamless chamber provides an internal surface that eliminates a potential source of contamination and makes the chamber exceptionally easy to clean.”
In fact, it pays to look for a wide range of features when shopping for a temperature-controlled shaker, and some seem more obvious than others. For example, most users would look for easy decontamination, but what about options that save money? For example, as Passanisi explains, the New Brunswick S41i includes a “sealed inner glass door for viewing the cultures without compromising the sample and environmental integrity.” He adds that this “also helps to reduce costly CO2 consumption.” So sometimes you can gain convenience and save money where you might not expect it.
Finding your features
When you go shopping for an incubator shaker, it’s worth putting together a checklist of what you need. For one thing, how much room do you have? The answer to that question might determine whether you need a shaker that sits on a benchtop or one that sits on the floor. Even various versions of benchtop and floor models offer a size range. For example, VWR’s Model 1585 floor shaker takes up a smaller footprint than most. Still, there’s much more to consider. How much do you want to shake? You should have an upper weight in mind. “All shakers have weight limits for maximum performance,” Das says, and a triple eccentric drive can handle heavier loads than a shaker with a single eccentric drive.
What you want to shake things in—the containers that you’ll use—should also be part of the purchasing decision. “Most manufacturers offer dedicated platforms that are designed to shake only a single vessel size, such as a flask,” Das explains. “These platforms provide maximum capacity and come with clamps installed versus universal platforms that provide maximum flexibility for using a mix of different-sized labware on a single platform.” If you don’t plan to shake things too vigorously, say less than 250 revolutions per minute (rpm), adhesive mats and tapes might be enough to keep your containers in place. Whatever you have in mind, think about writing down a list of all the possible containers and shaking speeds you’ll use to focus your search.
On top of those specifications, don’t forget the more obvious ones, like the temperature range. In general, refrigerated incubator shakers can take cells down to about 4 degrees Celsius, and high-temperature ones can go up to 80 degrees Celsius, which can be used to grow thermophiles. “Even if you just need incubated temperature ranges today, in the future you may want to perform protein studies where refrigerated temperatures of 16 degrees Celsius are required,” Das says. “Many customers opt for an incubated/ refrigerated shaker to grow with their needs.” He adds, “With these versatile units you can grow bacteria and yeast at 37 degrees Celsius or hold temperatures at 4 degrees Celsius, which makes cells ideal for protein expression studies, plasmid purification, and insect cell culture.”
Also, try to figure out how big a shaking range you need. As Das says, “Some models will shake as slow as 15 rpm for slowspeed staining applications and go as high as 1,200 rpm.”
When it comes to temperature and shaking speed, think also about how accurately you need to adjust those parameters. Where more accuracy is needed, go for a digital shaker, which displays the settings on an LED screen as opposed to analog controls. The digital version also benefits anyone who needs to repeat procedures accurately.
Fine-tuning your needs
In the end, some things matter more to some scientists than to others. For example, a review of the Thermo Shaker Incubator MTH-100 on Amazon.com points out its economical mixing blocks and a three-year warranty.
To help you focus on the best shaker for your needs, Thermo Fisher Scientific (Waltham, MA), provides an Orbital Shaker Selector Guide (http://shakerdigitalguide.thermoscientific.com/?ca=shakerguide). This tool helps you find the incubator shaker that will work in your lab. As today’s products show, there’s much more to a shaker than shaking. You need to know what, how much, how fast, and more to find the device that keeps everything in your lab shaken just right.
For additional resources on shakers, including useful articles and a list of manufacturers, visit www.labmanager.com/shakers