Gradient Gel Formation
Gradient Gel Formation - Related Videos
10:52
Denaturing Gradient Gel Electrophoresis (DGGE)
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Cited by 10 •
2007
07:31
Two-Dimensional Gel Electrophoresis
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2023
Two-dimensional gel electrophoresis (2DGE) is a technique that can resolve thousands of biomolecules from a mixture. This technique involves two distinct separation methods that have been coupled together: isoelectric focusing (IEF) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). This physically separates compounds across two axes of a gel by their isoelectric points (an electrochemical property) and their molecular weights. The procedure in this video covers the main...
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...
06:30
Gel Purification
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2023
Gel purification is used to recover DNA fragments after electrophoretic separation. DNA recovery from an agarose gel includes three basic steps: binding, washing and eluting from a silica column. DNA is believed to bind to silica in the presence of high salt via a salt bridge. Following binding, DNA is washed of impurities and eluted under low salt conditions disrupting this interaction. This video goes through a step-by-step, generalized procedure for cutting out a band from the gel, gel...
08:25
Using a Fluorescent PCR-capillary Gel Electrophoresis Technique to Genotype CRISPR/Cas9-mediated Knockout Mutants in a High-throughput Format
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Cited by 6 •
2017
The genotyping technique described here, which couples fluorescent polymerase chain reaction (PCR) to capillary gel electrophoresis, allows for high-throughput genotyping of nuclease-mediated knockout clones. It circumvents limitations faced by other genotyping techniques and is more cost effective than sequencing methods.
FAQs
As biomolecules migrate through the polymer network, they encounter progressively different levels of physical resistance rather than a single uniform environment. This changing resistance affects how molecules of different sizes move through the gel, extending the separation range within one material. The result is improved discrimination across a broad size range, which is especially useful for complex biological samples.
A uniform gel provides the same polymer environment throughout its thickness, so proteins with similar migration behavior may remain close together. A gradient introduces changing conditions along the migration path, allowing differences between proteins to become more apparent at different positions. This expanded separation can reveal bands that would overlap in a uniform gel and improve sample characterization.
The pattern depends on how solutions with different polymer concentrations are combined or layered before polymerization. Their arrangement establishes the concentration profile across the gel, while polymerization fixes that profile within a continuous network. Because the resulting material has spatially varying physical properties, the selected concentration distribution directly influences the resistance encountered during biomolecule migration.
A uniform gel presents one general polymer environment across its thickness, whereas a gradient gel presents a progressively changing environment. That distinction allows the gradient format to accommodate a broader range of biomolecule sizes and can separate proteins that appear insufficiently resolved in a uniform format. Consequently, gradient gels support more informative analysis of heterogeneous biological mixtures.
Preparation begins by creating solutions with different polymer concentrations and then combining or layering them so the composition changes across the intended gel thickness. The mixture is subsequently polymerized, which locks the concentration profile into a continuous network. Careful control of this sequence is important because the final gradient supplies the changing resistance used for molecular separation.
This approach is useful when a sample contains biomolecules spanning a broad size range or when proteins are expected to overlap in a uniform gel. The resulting separation can support molecular-weight estimation, protein sample characterization, and examination of complex biological mixtures. Its value therefore extends beyond producing distinct bands, providing information about the composition and size distribution of biological samples.