Centrifuges are indispensable pieces of equipment found in nearly every research and clinical laboratory. They play a critical role in separating particles from liquids based on density, enabling scientists and technicians to conduct a wide range of experiments and diagnostic tests. Whether you're working in molecular biology, chemistry, or biochemistry, centrifuges are essential for processes like isolating cells, purifying proteins, and separating blood components.
This guide will provide an in-depth look at how centrifuges work, their various applications, the key components that make them function, and the different types of centrifuges used in modern labs.
A centrifuge is a powerful tool that separates heterogeneous mixtures into their individual components based on density. By applying centrifugal force, centrifuges spin samples at high speeds, forcing denser particles to the bottom of the container and lighter particles to rise to the top. This process is commonly used in labs to separate liquids from solids, such as separating blood cells from plasma or isolating proteins from a solution.
One of the most common applications of centrifuges is in the separation of red blood cells, white blood cells, and platelets from whole blood. They are also used to purify cells, organelles, and viruses, making centrifuges indispensable in molecular biology and clinical diagnostics.
The centrifuge operates on the sedimentation principle, where particles in a solution naturally settle due to gravity. However, the centrifuge speeds up this process by applying centrifugal force, which creates a more efficient separation, even when the differences in density between the particles are minimal.
A centrifuge uses a motor to spin liquid samples at high speeds, generating a powerful centrifugal force. This force pushes denser particles outward, allowing for the rapid separation of substances. The speed at which a centrifuge operates is typically measured in revolutions per minute (RPM) or relative centrifugal force (RCF), also known as g-force. While RPM measures the speed of the rotor, RCF measures the actual force exerted on the samples, which is what separates the components based on density.
The centrifuge rotor, where the sample tubes are placed, is key to the separation process. As the rotor spins, the centrifugal force drives the denser particles to the bottom or sides of the sample tubes, while the lighter particles remain suspended. For some centrifuges, especially those handling temperature-sensitive samples, a refrigerated chamber is included to maintain a constant temperature during the separation process.
Centrifuges come with different rotor types, and the selection of a rotor depends on the specific application. Additionally, the sample tubes used, whether glass or plastic, play a role in the type of sample being processed.
By using centrifugal acceleration, a centrifuge greatly enhances the efficiency of separation compared to relying on gravity alone, allowing lab technicians and researchers to process samples quickly and accurately.
Centrifuges come in various types, each designed for specific applications. Whether you’re working with small samples or large volumes of temperature-sensitive materials, there’s a centrifuge that meets your needs. Below are the most common types of centrifuges and their applications.
Also known as benchtop centrifuges, these compact units are ideal for separating small volumes of samples, such as yeast cells and red blood cells. With speeds ranging from 3,000 to 7,000 g, they are commonly used for cell separation and routine sample preparation in general-purpose labs. Their small size and affordability make them a staple in many labs where basic separation tasks are performed.
These centrifuges are designed to handle larger sample volumes and feature a refrigerated rotor chamber, making them suitable for working with temperature-sensitive samples. With speeds up to 6,500 g, they are commonly used in clinical and research settings to separate blood components, cell fractions, and other substances that sediment quickly. The ability to switch out rotor chambers makes them versatile for labs needing to handle diverse sample sizes.
High-speed refrigerated centrifuges can reach speeds up to 60,000 g, making them ideal for more demanding applications. These centrifuges are commonly used in molecular biology, microbiology, and biochemistry labs to separate larger cellular organelles, microorganisms, and protein precipitates. Their ability to maintain low temperatures ensures the integrity of sensitive biological samples during high-speed separations.
Ultracentrifuges are the fastest centrifuges available, capable of reaching speeds up to 1,000,000 g. They are used for highly specialized tasks, such as isolating subcellular components, macromolecules, and viruses. These centrifuges are divided into two categories—preparative and analytical—based on the specific needs of the lab. Preparative ultracentrifuges are commonly used for separating large biomolecules, while analytical ultracentrifuges are employed to study macromolecule properties in real time.
Preparative Ultracentrifuges:
These centrifuges, which can reach speeds of around 600,000 g, are essential for separating large biomolecules and subcellular components, such as lipoproteins from plasma. They are widely used in research focusing on molecular and cell biology, allowing for precise separation of macromolecules for further analysis.
Analytical Ultracentrifuges:
Operating at speeds of around 500,000 g, analytical ultracentrifuges are equipped with advanced optical systems that allow scientists to observe the behavior of macromolecules during centrifugation. They are frequently used to study the size, shape, and interaction of molecules, making them crucial in the fields of biophysics and biochemistry.
Centrifuges are made up of several key components, each playing an essential role in the machine's functionality. Understanding these components can help you choose the right centrifuge for your lab's needs and ensure that you use the equipment effectively.
The rotor is the spinning component of the centrifuge, where sample tubes are placed. It generates the centrifugal force needed to separate the contents based on density. The type of rotor—whether swinging bucket or fixed angle—determines the direction and distribution of force on the samples, influencing how the separation occurs. The rotor's speed is critical for achieving the desired separation, especially in high-speed and ultracentrifuges.
The motor is the heart of the centrifuge, powering the rotor to achieve the necessary speeds for centrifugation. Depending on the type of centrifuge, motors can generate speeds from a few thousand RPMs in small bench models to over 100,000 RPMs in ultracentrifuges. The motor’s reliability and precision directly impact the performance of the centrifuge, making it a vital component in high-speed and temperature-sensitive applications.
Centrifuge tubes are specialized containers used to hold samples during centrifugation. These tubes are made of either glass or plastic, with glass being preferred for its chemical resistance and durability, and plastic offering a more affordable alternative. The size and material of the tube must be compatible with the rotor and the type of sample being processed. Larger samples may require centrifuge bottles, while smaller samples fit in traditional tubes.
The control panel allows users to set and monitor the centrifuge’s operating parameters, including speed (RPM), time, and temperature in refrigerated models. Advanced models may also feature digital displays, preset programs, and alarms for added safety. The control panel ensures that the centrifuge runs within the desired conditions, optimizing performance and protecting the integrity of samples.
The cost of a centrifuge can vary significantly depending on its type, features, and intended applications. Below is a breakdown of average costs for different types of centrifuges:
Benchtop centrifuges are the most affordable option, designed for small-scale labs and routine tasks. They typically cost between $1,000 and $5,000, depending on the model, speed, and capacity. These centrifuges are ideal for general-purpose applications, such as cell separation and sample preparation.
Large capacity and high-speed centrifuges are designed for labs that need to handle larger sample volumes or perform high-speed separations. These models range from $10,000 to $25,000, with refrigerated options costing more due to the added functionality of temperature control. They are commonly used in clinical, molecular biology, and biochemistry labs.
Ultracentrifuges are the most advanced and expensive centrifuges, capable of reaching extreme speeds for specialized applications such as virus isolation and macromolecule separation. The cost for ultracentrifuges can range from $10,000 to $50,000 or more, depending on the level of customization and additional features, such as refrigeration and optical systems for real-time analysis.
There are always additional costs to keep in mind! Adding refrigeration to any centrifuge model increases the price, as does purchasing extra rotors for specialized applications. Labs requiring high customization should expect additional costs based on their specific needs. Plan accordingly.
Deciding whether to lease or buy a centrifuge is a major financial decision. Both options have their advantages, and the choice you make can have a significant impact on your budget and operations, positively or negatively. Which option you go with all depends on your lab’s budget, long-term needs, and flexibility.
Purchasing a centrifuge outright gives you full ownership of the equipment, allowing you to use it without any ongoing financial obligations. Buying is an excellent option for labs that have the capital to invest upfront and need the centrifuge for long-term use. However, buying also comes with high initial costs, and you’ll be responsible for ongoing maintenance and repairs, which can add to the total cost of ownership over time.
Leasing a centrifuge is an attractive option for labs looking to preserve capital and maintain flexibility. With leasing, you avoid the large upfront costs associated with purchasing, and instead, make smaller, manageable monthly payments. Leasing also includes maintenance and repairs, saving you the hassle and expense of service contracts. Additionally, leasing allows labs to upgrade their equipment more easily at the end of the lease term, ensuring that they always have access to the latest technology.
Centrifuges are indispensable to research and clinical work, and separating particles based on density will be a key part to many of your workflows, whether you're working with small samples in a benchtop centrifuge or performing advanced research with an ultracentrifuge.
When it comes to acquiring a centrifuge, leasing can offer significant financial and operational benefits over buying, particularly for labs looking to conserve cash and remain flexible. Leasing with Excedr helps labs extend their cash runway, improve cash flow, and hit R&D milestones faster. It also offers the flexibility to upgrade equipment when needed, ensuring your lab can stay competitive without the strain of significant capital expenditures.
Contact us today to learn more about how our leasing solutions can support your lab’s growth.
