Why Use a Refrigerated Microfuge? Your Comprehensive Guide

A refrigerated microfuge adds two important elements to the classic centrifuge — coldness and smallness. While the basic operating principle is more or less the same, microfuges can accommodate tiny samples while keeping them cool as they go for a spin. Centrifugation is a tried-and-true process that has given us life-changing medicines, technologies and diagnoses throughout the years, and refrigerated microfuges further extend the possibilities.

With so many types of centrifuges, understanding the special capabilities of a refrigerated microfuge and when to use one can help you find the right equipment for your lab.

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What Is the Difference Between a Centrifuge and a Refrigerated Centrifuge?

When you picture a centrifuge, you probably think of a non-refrigerated version. This unit is called a ventilated centrifuge. When the rotors spin at high speeds, heavier substances in the samples sink to the bottom, while lighter substances stay at the top — a classic example of centrifugation. But all of that high-speed movement in a tight space generates heat, and some samples don’t tolerate heat well. They may break apart, change shape or behave differently.

A ventilated centrifuge draws ambient air into the bowl and sends it out through an exhaust. While this helps to dissipate heat, it doesn’t control the temperature, which can rise by several degrees compared to the ambient temperature. Unsurprisingly, a ventilated centrifuge is typically cheaper and smaller than its refrigerated cousin.

Refrigerated centrifuges compensate for the heat generated during rotation and offer precise temperature controls to keep delicate samples intact, often at temperatures between -40 and -20 degrees Celsius. They can both cool and maintain temperatures for exceptional stability.

Centrifuges vs. Microfuges

As you may have guessed by the prefix, microfuges, also called microcentrifuges, are a smaller type of centrifuge. They're geared toward working with small samples, usually with tubes holding 0.5, 1.5 or 2 milliliters of liquid. These smaller sample sizes are common in fields like molecular biology and biochemistry.

Microfuges typically spin at much higher speeds than centrifuges, which can aid in tasks like DNA and RNA extraction, protein isolation, cell fractionation and molecule separation. Like standard centrifuges, microfuges come in refrigerated and non-refrigerated varieties.

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Why Use a Refrigerated Microfuge?

A cooled environment is necessary for many types of samples in clinical and research settings, such as hospitals, universities, blood banks, biotechnology labs and pharmaceutical companies. You may even find refrigerated microfuges used in the chemical and food industries for separation and purification.

However it's used, refrigeration maintains the sample's integrity. If a sensitive biological sample starts to deteriorate during rotation, the results would be skewed and unreliable, and refrigeration helps prevent this scenario.

The uses of a refrigerated centrifuge or microcentrifuge are varied and include tasks like removing cellular debris and precipitates, separating proteins from other fluids and isolating DNA and RNA. You can also use them for enzyme assays, particle separation and blood component separation. By keeping samples cool, a refrigerated microfuge can protect the cells. For example, it might preserve enzymatic activity, retain structural integrity or prevent nucleic acid degradation.

A refrigerated microfuge is a necessity for many processes, and adding one to your lab can offer further benefits, such as:

  • Speed: Because they spin faster than centrifuges, you can separate smaller particles and molecules and finish some applications more efficiently.
  • Versatility: Refrigerated microfuges are incredibly versatile, so you can perform more analyses in the lab.
  • A compact footprint: Their small size means these instruments won't take up much of your precious floor or benchtop real estate.
  • Cost-effectiveness: If your lab mostly uses small sample volumes, a microfuge might be more cost-effective than a full-sized centrifuge.
  • Ease of use: Many refrigerated microfuges are particularly easy to use, thanks to improved controls and user-friendly software.

Do You Need a Refrigerated Microfuge?

If you have sensitive samples that deteriorate when warmed, such as enzymes, blood factors or hormones, a refrigerated centrifuge is likely in order. If those samples tend to be smaller than 2 milliliters, a microfuge is your best bet.

Although it might be tempting to pull your regular centrifuge into a cold room and spin away, this tactic usually isn’t enough. It could reduce the air temperature in the bowl, but it wouldn’t be very effective at reducing the temperature of the rotor, which is needed to compensate for the heat created during rotation.

Refrigerated centrifuges are sealed, which helps them control heat more effectively. For applications that rely on precision and cold temperatures, a refrigerated instrument is a necessity. If size is your biggest concern, you may not need a refrigerated microfuge after all. You can find rotors for regular-sized centrifuges that accommodate the small sample sizes of a microfuge.

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Things to Consider When Buying a Refrigerated Microfuge

Buying a centrifuge calls for a strong understanding of your expected applications and the options available to you. Because centrifuges come in so many styles, you’ll need to ask yourself a few questions about what you need.

As you shop for a refrigerated centrifuge, consider the following aspects:

  • Compressor modulation: Cooling down a centrifuge is similar to cooling down a home. If you turn your AC on and off as you decide you need it, the temperature will fluctuate wildly. Instead of a thermostat, refrigerated centrifuges use a compressor to control the temperature, and those that modulate the compressor can control the temperature without turning the compressor on and off. Modulation can help keep temperature fluctuations to a minimum and may be useful for sensitive applications.
  • Rotor style: Typically, your rotor choices include swinging bucket rotors and fixed-angle rotors. Swinging bucket rotors spin the tubes at an increasing angle until the buckets move almost perpendicular to the rotor. They tend to be best for low-speed, high-capacity applications. A fixed-angle rotor keeps its tubes at a 45-degree angle the entire time and is best for high-speed, low-capacity applications. They can also move faster than swing bucket rotors.
  • Rotor material: A rotor's material will affect how quickly it cools and how well it maintains that temperature. Aluminum rotors tend to outperform carbon and titanium in these areas. If you use a non-aluminum rotor, you'll need to pre-cool it before running the unit.
  • Tube size: While all microfuges will have small tube sizes, you’ll still need to check that they accommodate your samples. If not, consider a refrigerated centrifuge.
  • Speed requirements: When determining your speed requirements, look at both revolutions per minute and relative centrifugal force.
  • Bench space: Thankfully, most refrigerated microfuges are quite small, so you probably don’t need to worry much about how much space they’ll take up. Still, try to plan for your unit and consider whether you need an especially compact instrument.

Another vital piece of the equation is how you’ll get your refrigerated microfuge. Buying used lab equipment from a trusted supplier is a great way to save big on the tools you need without taking on excessive risk.

At New Life Scientific, we have a wide selection of dependable centrifuges, each of which our experienced team has thoroughly inspected. Most products are ready to ship, so you can avoid the lead times of new equipment, and they’re all supported by our 120-day warranty.

Still not sure what’s right for you? Our team can help there, as well. We work with labs of all kinds and can help you find the ideal piece of equipment for your needs.

Invest in the Right Equipment for Your Laboratory

Refrigerated microfuges are a vital component in many labs, helping you protect sensitive samples while they go for a ride. The equipment you choose will impact the quality of your results, your workflow and your budget, so consider a used system that offers the features you need without a high markup.

The experienced team at New Life Scientific is here to help more labs get the equipment they need. Shop our collection of used microcentrifuges, or contact us today to discuss your needs!