Cell culture is complex. Challenges include contamination risks and environmental differences, often compounded by using improper lab equipment. In this article we will focus specifically on the laboratory shakers, and their advantages when it comes to cell culture.
Shaking has been used for cultivating various cell types, including bacteria, fungi, and plant or animal cells in suspension. Shaking promotes the growth of cells and microorganisms by improving aeration, facilitating oxygen transfer and by promoting more efficient mixing of cells with nutrients suspended in media, ultimately providing higher cell yields than static incubation and ensuring consistency while saving time and enhancing workflow efficiency.
Lab Manager Survey / Number of hours per day shaker is in operation.1
Agitation is achieved through rocking, linear shaking, or orbital shaking, all based on the same principle: a liquid-filled vessel on a moving platform agitates the liquid in a set pattern.
Orbital and linear (reciprocating) shakers are ideal for mixing liquids, dissolving solids, and most used in culturing cells. They ensure reliable, efficient, and controlled agitation. The purpose of shaking is to increase the availability of nutrients and to improve the oxygen transfer to gain a higher biomass compared to static incubation. Now the question is: Which one of these two works better for cell culture? Let 's dive into it.
Linear or reciprocating shakers are designed to create a back-and-forth motion for efficient mixing. Nowadays, they are mostly used in molecular biology and chemistry for tasks like staining and destaining gels, washing blots, solubility studies, or mixing in separatory flasks and funnels during chemical extractions.
When using reciprocating shakers, fluid movement starts with a surge, turns into a curling motion, and eventually forms a swirl. This pattern depends a lot on the liquid's viscosity and can become turbulent and unpredictable based on how full the container is and the shaking speed. At higher speeds, you might even get unexpected geyser-like splashes that can wet the flask's closure, risking contamination and reducing aeration. Because of these issues, reciprocating shakers aren’t as popular for cell cultivation in labs anymore.
Orbital shakers are widely regarded as an essential tool for the cultivation of microbial, algal, and mammalian cultures. By rotating their platforms in a circular motion, they generate a consistent swirling pattern with laminar flow. This motion, unlike that of reciprocating shakers, is less influenced by factors such as media viscosity, ramp-up speed, or fill volumes, making orbital shakers particularly suited for shear-sensitive cells.
Ensuring uniform liquid distribution is critical for achieving consistent results in parallel experiments, which is why orbital shakers are frequently employed in the cultivation of microorganisms and cells. Advanced models offer features such as temperature control, photosynthetic lighting, and CO² regulation to accommodate diverse culture requirements.
Typical applications include cell expansion for plasmid or protein expression, media development, screening, and inoculum preparation. The majority of research involving microorganism cultivation relies on orbital shakers, and have become an indispensable equipment in modern laboratories.
Factors to consider when selecting a laboratory shaker:
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Agitation speed: Most shakers offer an adjustable speed range, typically between 12 and 1,800 rpm or 40 and 6,000 rpm, although fixed-speed models are also available. It is crucial to ensure that the speed range of the device you plan to purchase aligns with the requirements of your application. For enhanced precision and repeatability, a digital display for speed control can be highly beneficial.
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Capacity and Size: Ensure that the device's maximum shaking capacity is compatible with the laboratory's requirements, including the volume and quantity of samples to be processed.
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Motor Power: Consider the viscosity and volume of your samples carefully when selecting a motor.
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Timer: Enables you to set the shaking duration, after which the appliance will automatically stop.
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Digital Controller: The shakers LED controllers for speed and timer allow the user to set the shaker while they work on other critical tasks while setting up alarms.
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Stable Movement: Digital speed control system guarantees stable movement and prevents splashing, ensuring accurate and consistent results.
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Temperature Control: For applications needing regulated temperatures, choose an incubator shaker with precise control.
The following are important questions to answer before purchasing a laboratory shaker:
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What is your primary application?
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What is the unit's capacity in terms of both weight and volume?
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What accessories are compatible with the unit?
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What is the RPM range, and in what increments can it be adjusted?
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Do you need a temperature-controlled shaker, such as an incubating or water-bath shaker, or one with cooling capabilities?
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What type of shaking motion do you require—orbital, linear (reciprocal), or rocking?
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Does the unit offer any programming functions? If so, what are they?
Additional and optional features to consider.
Many laboratories have a main application in mind, along with a secondary application, making a versatile, multipurpose shaker an ideal choice. Some less common shakers include the feature of Dual Shaking Modes that supports both orbital and linear shaking, providing easy switching between modes for different applications.
Jeio Tech OS-2000 and OS-3000 Dual Shakers
To achieve optimal results, users must pair their shaker with the appropriate accessories. Many manufacturers provide an extensive selection of add-ons, such as platform attachments designed to accommodate various types of glassware.
AS 260.1 Universal Attachment for the IKA KS 3000 i control incubated orbital shaker.
Maintaining Temperature Control During Sample Mixing.
For cell culture, the precision of temperature control can mean the difference between success and failure. The growth of microorganisms relies on maintaining optimal conditions, with proper aeration provided by the shaker and precise temperature regulation ensuring the appropriate environment. Temperature requirements can vary depending on the culture; while many are cultivated at 37°C, alternative temperatures are often necessary for specific studies, such as those involving protein expression. In such cases an incubator comes into place.
Most shakers work in standard incubators with temperatures between 4 – 40°C, but CO² incubators and high-humidity environments need specialized models. It’s important to check if a shaker is designed to handle warm, humid conditions and its specific limitations. Temperature control is an important feature, and when working with a CO² incubator, it is important to select a shaker that is compatible with a CO² rich environment, one specifically designed for corrosive environments.
Ensure its dimensions, inclusive of its orbit, fits in the incubator. For power supply, some incubators may have an internal power supply, but it is not always needed. The Orbi-Shaker™ CO²'s could be a good option, as it is powered through a thin ribbon cable connected to an external control panel outside the incubator, ensuring the incubator door seal remains intact. This and similar units include a remote controller, enabling you to adjust shaker settings effortlessly without opening the incubator door.
For incubated shaking, using an incubated shaker is a more practical alternative to placing an orbital shaker inside an incubator. This approach not only offers greater convenience but is also more space-efficient compared to using separate equipment. Selecting the most suitable option will depend on your budget and the primary applications conducted in the laboratory.
When selecting a shaker platform with temperature control, evaluate key features such as temperature uniformity, stability, and adjustability.
The level of precision required will vary depending on the application, with some requiring strict temperature tolerances. In these instances, ensure that the incubator can achieve and maintain the desired temperature with minimal variation before purchasing. Ensure consistency throughout the chamber so that the temperature is the same at every point. Rapid recovery of the temperature environment after opening and closing the incubator is equally important. Additionally, the capability to program temperature changes over time is a key feature for experiments requiring precise control.
For added convenience, opt for an incubator shaker with clear windows that allow users to easily monitor mixing efficiency and quickly identify any issues. A platform designed for easy access also enables users to remove individual samples for periodic testing with minimal hassle.
The shaker may be just one component of a successful suspension cell culture, but it plays a critical role that requires careful consideration. Its function goes beyond simple agitation; it ensures proper mixing, aeration, and nutrient distribution, all of which are essential for optimal cell growth and viability. Choosing the right shaker with appropriate speed and motion settings can greatly impact the overall success of your culture process.
References:
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How Laboratory Shakers Are Being Used and What To Look For When Buying / https://www.labmanager.com
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Critical analysis of engineering aspects of shaken flask bioreactors/ National Library of Medicine: https://pubmed.ncbi.nlm.nih.gov/19929318/
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Optimize Cell Growth with a Biological Shaker / https://www.fishersci.com/us/en/scientific-products/publications/lab-reporter/2022/issue-1/optimize-cell-growth-with-a-biological-shaker.html
