Stacking Gel
Stacking Gel - Related Videos
09:38
Scaling of Engineered Vascular Grafts Using 3D Printed Guides and the Ring Stacking Method
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Cited by 6 •
2017
Scalable engineered blood vessels would improve clinical applicability. Using easily sizable 3D-printed guides, rings of vascular smooth muscle were created and stacked into a tubular form, forming a vascular graft. Grafts can be sized to meet the range of human coronary artery dimensions by simply changing the 3D-printed guide size.
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...
11:03
Pouring and Running a Protein Gel by reusing Commercial Cassettes
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Cited by 2 •
2012
Our protocol demonstrates how to pour multiple protein gels at a time by recycling Invitrogen Nupage Novex minigel cassettes, and inexpensive materials purchased at a home improvement store. This economical and streamlined method includes a way to store the gels at 4°C for a few weeks. By re-using the plastic gel cassettes from commercially available gels, labs that run frequent protein gels can save significant costs and help the environment.
09:22
DNA Gel Electrophoresis
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2023
DNA gel electrophoresis is a technique used for the detection and separation of DNA molecules. An electric field is applied to a gel matrix comprised of agarose, and within the gel, charge particles will migrate and separate based on size. The negatively charged phosphates of the DNA backbone cause DNA fragments to move toward the anode - a positively charged electrode. The video explains the mechanism by which DNA fragments are resolved on an agarose gel, and it provides a step-by-step...
10:55
Staining Proteins in Gels
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Cited by 7 •
2008
Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. Staining of proteins with Coomassie Blue, Silver Staining, SYPRO Orange, SYPRO Ruby are demonstrated in this video.
FAQs
The lower pH changes the relative migration behavior of the buffer ions surrounding the protein-SDS complexes. Fast-moving chloride ions and slower glycine ions establish a moving ion boundary, causing the protein complexes to gather within a narrow region. This concentration step reduces the initial spread of the sample before it enters the resolving portion of the gel.
Chloride ions migrate rapidly, whereas glycine ions move more slowly under the stacking conditions. Protein-SDS complexes become concentrated between these leading and trailing ion populations as the boundary moves through the gel. The resulting focused band gives the proteins a more uniform starting position, which supports clearer separation later in the electrophoresis run.
A stacking gel has a lower polyacrylamide concentration than the resolving gel, producing larger pores. These larger pores allow the protein-SDS complexes to pass through the stacking layer while the ion boundary concentrates them. The contrast with the tighter resolving gel is important because stacking focuses the sample first, while the subsequent layer provides the separation used for comparison.
The two layers perform complementary tasks. The stacking gel concentrates proteins into a narrow band through its ion-migration conditions, lower pH, and larger pores. The resolving gel then separates the focused protein-SDS complexes, allowing differences associated with protein size to become visible. Without effective concentration before separation, bands may be broader and comparisons less distinct.
In the SDS-PAGE arrangement described, the stacking layer is placed before the resolving gel in the direction of protein migration. Protein samples enter the low-concentration layer, where the ion boundary focuses their complexes into a narrow band. The concentrated material then proceeds into the resolving gel, where separation occurs and the resulting bands can be compared.
Sharper bands make it easier to compare protein size and assess the composition of a sample. They also support evaluation of expression results, such as whether a protein pattern changes between samples, and purification results, such as whether the sample profile becomes more focused toward the expected protein components. The stacking step therefore improves interpretation of the electrophoresis pattern.
This layer is useful whenever researchers need to compare protein patterns between biological samples or evaluate material collected during purification. By concentrating proteins before they reach the resolving gel, it improves band sharpness and resolution. The resulting pattern can help researchers examine sample composition and compare expression or purification results within SDS-PAGE-based biological analyses.