Analytical Ultracentrifuge
Analytical Ultracentrifuge - Related Videos
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.
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.
05:40
Fabricating Cotton Analytical Devices
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2016
To investigate simple fabrication approaches for multiple assay needs, we created a fluid-absorbing channel system made of cotton material. This device was used to establish a multiple detection platform, and solve contamination issues that commonly affect lateral flow-based biomedical devices, for clinical urinalysis of nitrite, total protein, and urobilinogen.
09:51
Sample Preparation for Analytical Characterization
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2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia Sample preparation is the way in which a sample is treated to prepare for analysis. Careful sample preparation is critical in analytical chemistry to accurately generate either a standard or unknown sample for a chemical measurement. Errors in analytical chemistry methods are categorized as random or systematic. Random errors are errors due to change and are often due to noise in instrument. Systematic errors are due to...
FAQs
The observed sedimentation rate reflects several properties at once: molecular mass, shape, density, and interactions with other molecules. A larger mass can influence movement, but shape and density also affect how a particle behaves in solution. Because these factors act together, sedimentation data can provide information about molecular structure and assembly rather than serving as a simple size measurement.
A sedimentation coefficient summarizes how rapidly a molecule or molecular assembly moves through solution under a centrifugal field. Its value can help characterize purified proteins, nucleic acids, viruses, and complexes, particularly when interpreted alongside the particle's mass, shape, density, and interaction state. Comparing these measurements can also help identify distinct species within a sample.
Optical systems monitor concentration changes in the sample cell while centrifugation is occurring. This real-time observation tracks how biological material redistributes as it sediments, allowing researchers to analyze movement rather than relying only on a final separation. The resulting concentration behavior supports measurements of sedimentation coefficients, molecular mass, and sample heterogeneity.
Association changes the molecular assembly being observed, which can alter its sedimentation behavior. Analytical ultracentrifugation can therefore reveal reversible interactions such as protein oligomerization or binding between proteins and nucleic acids. Examining these behavior changes helps investigators study whether macromolecules exist as separate species or participate in assemblies under the measured conditions.
A biological sample is placed in a sample cell and subjected to high-speed centrifugation. As particles move through solution, the instrument's optical system follows concentration changes in real time. Researchers then use the observed sedimentation behavior to characterize the material, estimate molecular mass, assess heterogeneity, or examine molecular interactions.
The method supports analysis of purified proteins, nucleic acids, viruses, and other macromolecular complexes. This range makes it useful for studying both individual biological macromolecules and assemblies formed through molecular interactions. The measurements can address composition-related questions, such as whether a preparation contains multiple species or reversible associations.
Analytical ultracentrifugation examines macromolecules while they remain in solution, without requiring immobilization or labeling. That feature allows researchers to characterize biological particles and their assemblies through their movement in a centrifugal field. It is especially relevant when studying reversible associations, because the observed behavior can reflect molecular interactions in solution rather than attachment to a surface.