Ultracentrifuge Operation
Ultracentrifuge Operation - Related Videos
08:42
Density Gradient Ultracentrifugation
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2023
Density gradient ultracentrifugation is a common technique used to isolate and purify biomolecules and cell structures. This technique exploits the fact that, in suspension, particles that are more dense than the solvent will sediment, while those that are less dense will float. A high-speed ultracentrifuge is used to accelerate this process in order to separate biomolecules within a density gradient, which can be established by layering liquids of decreasing density in a centrifuge tube. The...
03:04
Ultracentrifugation-Based Isolation of Legionella pneumophila Outer Membrane Vesicles
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2026
Source: Jung, A. L., et al. Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages. J. Vis. Exp. (2017)This video demonstrates the isolation of outer membrane vesicles (OMVs) from Legionella pneumophila using sequential centrifugation, sterile filtration, and ultracentrifugation. The purified OMVs, enriched in membrane proteins and lipopolysaccharides, are suitable for host-pathogen interaction studies.
11:36
Assembly, Loading, and Alignment of an Analytical Ultracentrifuge Sample Cell
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Cited by 21 •
2009
The analytical ultracentrifuge (AUC) sample cell holds sample and reference buffer and during experiments and is exposed to high vacuum and rotor speeds up to 60,000 rpm. This video will demonstrate the rigorous attention to detail necessary for assembly, loading and alignment of this very important component of an AUC experiment.
06:47
Isolation and Analysis of Plasma Lipoproteins by Ultracentrifugation
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Cited by 9 •
2021
Several methods have been used for analyzing plasma lipoproteins; however, ultracentrifugation is still one of the most popular and reliable methods. Here, we describe a method regarding how to isolate lipoproteins from plasma using sequential density ultracentrifugation and how to analyze the apolipoproteins for both diagnostic and research purposes.
07:57
Operating the Glovebox
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2023
Robert M Rioux, Ajay Sathe, Zhifeng Chen, Pennsylvania State University, University Park, PA A glovebox is an isolated enclosure that is designed to maintain an inert atmosphere. The manipulation of chemicals or apparatus is done via the use of gloves, which allow operation while still maintaining an inert atmosphere. A positive pressure is utilized to compensate for any passive leaks. Objects can be transferred in and out of the box using an antechamber that acts as an airlock between the box...
FAQs
These properties determine how quickly a component moves through the liquid during rotation. Larger mass can alter sedimentation behavior, while molecular shape and buoyant density influence resistance to movement and position relative to the solvent. Because solvent viscosity also affects motion, changing the liquid environment can change separation quality and the apparent distribution of components.
Viscosity controls how readily particles or molecules move through the solvent under centrifugal force. A more viscous liquid can reduce movement, whereas a less viscous environment may permit faster sedimentation. Accounting for viscosity helps chemists interpret separation behavior and select controlled conditions when comparing samples, characterizing macromolecules, or examining colloidal systems.
Differential centrifugation separates components according to differences in sedimentation behavior under selected spinning conditions. Density-gradient centrifugation adds a liquid density profile, allowing components to fractionate according to how their movement relates to buoyant density. The two approaches therefore support different separation strategies when chemists need to fractionate mixtures or examine molecular and colloidal properties.
Rotor speed, temperature, sample loading, and run time directly influence resolution and reproducibility. Speed and duration affect how far components move, while temperature can alter the sample environment and solvent behavior. Excessive or inconsistent loading can reduce separation quality. Controlling these variables systematically makes results easier to compare across experiments and supports safer instrument use.
Samples should be placed in a properly balanced rotor, with loading conditions controlled before rotation begins. The operator should also set the intended rotor speed, temperature, and run time rather than treating them as interchangeable settings. These checks reduce uneven operation, promote reproducible sedimentation, and help protect the instrument during high-speed use.
Chemists may select this approach to fractionate mixtures, characterize macromolecules, isolate nanoparticles, or investigate aggregation and molecular interactions. It is especially useful when components differ in sedimentation behavior and require separation or analysis under controlled conditions. The resulting fractions or sedimentation patterns can provide information about composition, particle behavior, and interactions within the sample.
High-speed separation can isolate nanoparticles from a mixture and help examine colloids according to their sedimentation behavior. Because particle movement depends on mass, shape, buoyant density, and solvent viscosity, controlled operating conditions are essential for interpreting the outcome. Such experiments can also reveal aggregation, showing how particles or components behave collectively rather than independently.