Percoll Gradient
Percoll Gradient - Related Videos
09:58
Isolation of Brain and Spinal Cord Mononuclear Cells Using Percoll Gradients
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Cited by 133 •
2011
The current article describes a rapid protocol to efficiently isolate mononuclear cells from brain and spinal cord tissues that can be effectively utilized for flow cytometric analyses.
08:30
Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
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Cited by 43 •
2011
A method to prepare translationally active, intact synaptoneurosomes (SNs) from mouse brain cortex is described. The method uses a discontinuous Percoll-sucrose density gradient allowing for the quick preparation of active SNs.
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...
03:36
Purification of Bacteriophages Using a Sucrose Density Gradient
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2026
Source: Rustad, M., et.al. Synthesis of Infectious Bacteriophages in an E. coli-based Cell-free Expression System. J. Vis. Exp. (2017)This video demonstrates the purification of bacteriophages from a suspension containing host bacterial debris using a sucrose density gradient. It shows how the density gradient separates phages by buoyant density, enabling recovery of a visible band for resuspension and further analysis.
10:52
Denaturing Gradient Gel Electrophoresis (DGGE)
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Cited by 10 •
2007
FAQs
During centrifugation, cells, organelles, or microorganisms move through the Percoll medium until they reach positions corresponding to their buoyant densities. Particles with different densities therefore occupy different locations and can be recovered as separate fractions. This physical separation helps distinguish cellular material that would otherwise remain mixed in a complex biological sample.
Percoll consists of colloidal silica suspended in a medium and coated with polyvinylpyrrolidone. This formulation provides the density-based environment through which biological particles migrate during centrifugation. The resulting gradient supports fractionation while making it possible to isolate populations according to density rather than relying only on their original location in the sample.
Different sample components have different buoyant densities, so they settle at distinct positions within the gradient during centrifugation. Debris, leukocytes, immune subsets, and other particles can consequently become distributed among separate fractions. Recovering selected fractions reduces sample heterogeneity and provides cleaner material for subsequent analysis or functional testing.
Immune cell subsets may occupy different positions when their buoyant densities differ sufficiently within the gradient. Researchers can collect the corresponding fractions and examine them as enriched populations rather than analyzing the entire mixed sample. This approach supports downstream characterization by flow cytometry, microscopy, or functional assays while reducing interference from unrelated material.
A sample is placed into a Percoll-based density arrangement and subjected to centrifugation so its components migrate to density-matched positions. After separation, the desired layers or fractions are recovered for further study. The isolated material can then be examined by flow cytometry, microscopy, culture, or functional assays, depending on the research objective.
The method can be applied to samples containing cells, organelles, or microorganisms, including complex material encountered in immunology and infection research. Its value is greatest when the starting sample contains mixed populations or substantial debris. Fractionation can enrich leukocytes, immune cell subsets, pathogens, or infected cells for more focused downstream investigation.
Recovered fractions can provide enriched material for examining pathogens or infected cells separately from other sample components. Researchers may use these preparations for culture, microscopy, flow cytometry, or functional assays. By reducing debris and cellular heterogeneity, the approach helps produce samples better suited to detecting, characterizing, or testing the biological behavior of the target population.