Ultracentrifugation Concentration
Ultracentrifugation Concentration - 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.
02:41
Concentration Cells
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2020
A concentration cell is a type of a voltaic cell constructed by connecting two almost identical half-cells, both based on the same half-reaction and using the same electrode, differing only in the concentration of one redox species. A concentration cell's potential, therefore, is determined only by the concentration difference of the particular redox species. Consider the following voltaic cell: From the given information, the cell potential of this concentration cell can be calculated using...
04:11
Exosome Isolation: A Density-based Ultracentrifugation Technique Using Sucrose Cushion to Separate Exosomes from Conditioned Media of Cultured Cells
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2023
This video describes a density-based ultracentrifugation technique for isolating exosomes from conditioned media harvested from human embryonic kidney cell cultures using a 25% (w/w) sucrose cushion prepared in deuterium oxide. The isolated exosomes can be used for downstream applications.
FAQs
Separation reflects how rapidly suspended material moves under centrifugal force. Particle size, shape, and density influence sedimentation rate, so components may travel different distances through a solution or density gradient. This behavior allows researchers to enrich selected macromolecules or particles while reducing their association with other sample components, supporting more targeted downstream genetic analysis.
A pellet forms when sedimenting material collects at the bottom of the sample, whereas a concentrated band forms when material remains localized within a density gradient. These outcomes provide different physical locations for recovery after spinning. The distinction matters because researchers can collect either broadly sedimented material or a more specifically positioned fraction for molecular characterization.
Concentrating a sample places more of its target material into a smaller volume and can reduce accompanying contaminants. This enrichment makes low-abundance nucleic acids, viruses, ribonucleoprotein complexes, or cellular components easier to detect and characterize. It can also support more reproducible comparisons by producing a preparation better suited to subsequent molecular studies.
The sample environment influences how particles migrate and where they can be recovered. A solution permits sedimentation according to particle properties, while a density gradient provides a medium through which components can form concentrated bands. Choosing between these approaches depends on whether the objective is to collect sedimented material or distinguish material by its movement through the sample.
A typical workflow places the suspended sample in a solution or density gradient, applies extremely high centrifugal force, and allows the desired material to sediment or form a concentrated band. The recovered pellet or band is then used for downstream work. This sequence reduces sample volume while preserving enriched material for genetic or molecular characterization.
The technique is useful when genetic studies require preparation or purification of nucleic acids, viruses, ribonucleoprotein complexes, or cellular components. Enriching these materials can improve their detectability and support molecular characterization, particularly when they occur at low abundance. It therefore serves as a preparation step before genomic and other molecular analyses.