Background and History
Gel Electrophoresis refers to the process of separating biological molecules by size within a gel matrix.
Electrophoresis has been around for a very long time and first became commonplace during World War II among military biomedical researchers.
However, it did not gain popularity as a public research tool until the genetic revolution of the 1960s.
Older equipment was unwieldy and expensive, and did not have safety and convenience features. The same principles still govern technology used today, though!
Electrophoresis uses a controlled voltage that propels them from the negatively charged anode end towards the positively charged cathode end of the chamber.
The chamber is filled with electrical buffers that conduct voltage through the gel, which drives motion of molecules through the latticework of the gel.
The Sub20 Maxi Gel System, pictured above
Smaller molecules move through the gel faster than the large ones, which produces a size-based gradient from the top to the bottom of the gel.
Sizes can be approximated using a visual ladder of similar molecules with known sizes that is run with the samples of interest.
That said, there are different types of molecules that can be separated with electrophoresis (just in case you don’t know) and different methods for doing this.
Types of Electrophoresis Boxes and their Purpose
Electrophoresis boxes come as two main types. They are used for distinct purposes in laboratories.
Vertical Gel systems are viewed from the side of the box while running. They do not run molecules based on their native charge.
The molecules run through a reducing layer of gel that coats proteins in negative charge and then separate by size in the lower resolving layer.
Horizontal Gel systems are viewed from above and run molecules from the black end (anode end, negatively charged) to the red end (cathode end, positively charged).
These systems assume all molecules have a negative charge and will run towards the positively charged end at a speed inversely proportional to their size.
Features to Look For in a Box
The main features to look for when choosing a DNA gel box are the dimensions and their compatibility with your protocols.
Some other things to consider:
- Will you be doing high-throughput work?
If so, you will want multichannel pipette compatibility from your wells.
- How small or large are your DNA fragments?
Larger fragments will need more space to run and resolve.
- How many people will run gels at once?
Boxes that can accommodate multiple gels may be convenient. See these two casting tray and three casting tray gel boxes.
- How concentrated are your samples?
If samples are very dilute, you may need thicker combs and fewer wells.
- How experienced are the users of the equipment?
Inexperienced users may benefit more from boxes with extra safety and convenience features like the Hoefer line.
Gel Combs for Different Contexts
Combs are often an afterthought for those who have just begun working with DNA gels, but they shouldn’t be. Combs are the cornerstone of gel quality it sets.
Types of Combs and Sample Setups
The comb determines the size and number of wells available on your gel. 1.0mm combs are thinner and create a smaller well volume.
1.5mm combs are thicker and make the wells larger in volume. The more wells your comb has, the smaller those wells will be.
How to Use Gel Combs: Two Contrasting Examples
- A 1.5mm 6-well comb allows a large volume to be added to each well. You can run samples of about 50 ul.
So, let’s say you have low concentrations of DNA and need to run a large volume of your samples in order to detect bands.
In this case you will want to choose the comb with the fewest wells and largest volume.
2. On the other hand, if you have a lot of samples and want to use a low volume, you may choose a 1.0mm 24-well comb.
This will have you running sample volumes as low as 10 ul. This is appropriate when your samples are high in concentration.
MultiChannel Pipette Compatibility
Most combs are constructed for traditional pipettes only, but some boxes come with combs intended for work with multichannel pipettors.
For example, the Labnet Enduro boxes with 10x10cm dimensions and greater are intended for use in high-throughput regimens.
These boxes come equipped with combs that allow you to add samples using a multichannel pipette.
Safety and Convenience Features to Look for
All modern boxes come with a few safety features like lids that lock and voltage that automatically shuts off when the lid is lifted.
Additionally, inexperienced users may benefit from some of the following additional features:
- Color coded combs
- Color coded loading strips
- Side handles
- Lower volume chambers to prevent splashing
- Timers for on/off
The Hoefer line includes these features for all of its horizontal electrophoresis boxes.
Shop DNA Gel Boxes and Accessories with Stellar
Now that you have a better idea of what you are looking for, come browse our Enduro and Hoefer boxes, two-top-of-the-line brands that can get any job done.
They feature durable, coated electrodes that carefully regulate voltage and keep users safe without compromising the efficiency of your results.
Our boxes are safe, convenient, and adapt easily to high-throughput protocols with hundreds of samples.
Need to run mini gels? That’s well within reach! See the Sub6 mini and the Enduro 7.7 for routine low throughput jobs.
For labs that are overwhelmed with different users, consider a two casting tray or three casting tray gel box so everyone can go home happy.
Other DNA Gel Accessories
At Stellar Scientific, we aim to give you a stress free shopping experience whenever we can. For that reason, we carry a vast selection of combs for Enduro gel boxes.
We also carry DNA ladders for identifying fragments from 2.5kb all the way down to 100 or even 50 base pairs.
All set accessorizing your boxes, but need to process the results? We have gel documentation systems and accessories on our website too.
What comes next after that first DNA gel runs? Find kits for gel extractions, cloning, PCR and more in our molecular biology section.
There’s no need to limit yourself to what comes with your box! We can also help you with ordering anything that you can’t find on the website. Don’t hesitate to contact us if you need anything.
Footnotes:
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- Suárez-Díaz E. (2022). The Electrophoretic Revolution in the 1960s: Historical Epistemology Meets the Global History of Science and Technology. Berichte zur Wissenschaftsgeschichte, 45(3), 332–343. https://doi.org/10.1002/bewi.202200024