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Biotech Life Science
Gel Electrophoresis Equipment

How Gel Electrophoresis Works & How We Save You Time & Money

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Gel electrophoresis equipment

Electrophoresis is used in the life sciences and biotechnology to separate and extract DNA fragments, RNA, and proteins, based on their size and charge, in order to analyze them.

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It is used as a preparative technique in laboratories for PCR, Southern blotting, genome mapping, and DNA sequencing, and is also used in DNA fingerprinting and plant breeding. Scientists studying molecular biology, microbiology, and biochemistry utilize electrophoresis for studies and experiments in medicine, forensic science, and conservation biology, just to name a few.

Gel electrophoresis is one of the most common electrophoresis methods used.

In these systems, molecular samples are loaded into the electrophoresis apparatus, a type of box or chamber referred to as a gel box. The gel box is filled with an agarose or polyacrylamide gel and is equipped with a gel comb, as well as a negative electrode, or anode, on one side, and a positive electrode, or cathode, on the other. The comb helps form the wells where the samples are placed, and the negative and positive electrodes create an electrical current that generates electrophoretic separation.

The electrical current generated separates the DNA fragments based on their size or charge because, even though DNA molecules have the same amount of charge per mass, longer DNA fragments tend to have a higher molecular weight compared to shorter DNA pieces. That difference means segments move at varying speeds through the gel medium, grouping up according to size.

After gel electrophoresis is performed, the gel is stained with a fluorescent binding dye, which eventually allows the groups that formed to be more easily observed. Having stained the gel, a light source is then used to excite the fluorescent dye so that the DNA bands are visible for post-separation and analysis.

A well-defined group or line of DNA is referred to as a separation band. These separation bands tell us more about the DNA fragments size or charge.

Gel Types, Techniques, Buffers, & Automation

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There are different types of gel used for different tasks, and the amount used can vary depending on the size of macromolecules in the sample.

The gel interacts with a buffer that affects the porousness of the gel matrix. Depending on the application, you’ll want to use a certain gel.


Agarose gels are made from the natural polysaccharide polymers found in seaweed. Agar is extracted by heating seaweed for several hours. After washing and alkaline pre-treatment, the seaweed is submerged in boiling water.

The agar dissolves into the water and the mixture is filtered to remove any residual seaweed matter. It is easily handled and cast compared to other matrices because the casting is done physically rather than with the assistance of chemicals. It is also capable of being stored for later use.

Because agarose gel does not have a uniform pore size, it is ideal for testing that involves molecules that are larger than 200 kDa, or 200 kilodaltons. The percent of agarose in the gel influences the distances between DNA bands of different lengths.

Precast agarose gels are also available, and do away with messy and time-consuming prep work. They run up to twice as fast as traditional handcast gels and come in a variety of agarose percentages, well formats, and throughput capacities.


While most modern techniques involve agarose gel, polyacrylamide gel can also be used for specific applications in similar ways. The uniformity of polyacrylamide gel allows for better accuracy, and is controlled using acrylamide and bis-acrylamide powder to create the gel.

Varying the percentage of polyacrylamide in the gel affects the pore size. Because polyacrylamide gel is biologically inert, modulating the stiffness of the gel using the powder does not affect its biochemical properties. This allows for observations that can be made based on the stiffness of the gel and no other competing changes in cellular functions.

Nucleic Acid Electrophoresis

This technique is used to separate and analyze DNA or RNA fragments by size and reactivity. It involves segmenting the molecules using a restriction enzyme.

After segmentation, the samples are placed in the gel for size and charge separation, and are then dyed using a fluorescent dye specifically for DNA. This allows for easy observation. Agarose gel is most often used in systems that perform nucleic acid gel electrophoresis.

Some applications of agarose gel electrophoresis include:

  • Analysis of PCR (polymerase chain reaction) products. Examples include genetic fingerprinting, molecular cloning, or molecular genetic diagnosis
  • Separation of restricted genomic DNA before Southern transfer, or Southern blot
  • Separation of DNA fragments for extraction and purification
  • Estimation of the size of DNA after digestion using a restriction enzyme

There are a variety of nucleic acid-specific devices available, including vertical electrophoresis systems, which are available in midid or mini gel electrophoresis format. Vertical systems are more ideal for proteins, unlike horizontal systems which are well suited for DNA and RNA.

The vertical systems utilize a discontinuous buffer system, where the top chamber contains the cathode and the bottom chamber contains the anode, and a thin gel is poured between two glass plates that are mounted. This submerges the bottom of the gel in one chamber, while the top of the gel is submerged in buffer in the top chamber.

After applying an electrical current, a small amount of buffer migrates through the gel from the top chamber to the bottom chamber. This allows for precise control of voltage gradients during separation, and results in greater separation and resolution.

Protein Electrophoresis

Polyacrylamide gel is often used in gel electrophoresis of proteins, and is ideal for protein separation and analysis. This method is commonly used in the field of immunology. It is typical for polyacrylamide gel electrophoresis (PAGE) systems to run vertically, so that the stacking and resolving gels form a continuous gel, which would be much more difficult in a horizontal gel.

It also allows a much greater protein amount to be loaded onto the gel. Protein Electrophoresis analyzes the proteins in a fluid or extract. Because of practical limitations, protein electrophoresis is generally not suited as a preparative method.

PAGE applications include:

  • Peptide mapping
  • Estimation of protein size
  • Protein quantitation
  • Measuring molecular weight
  • Comparison of the polypeptide composition of different samples
  • Analysis of the number and size of polypeptide subunits


Buffers are used to help transmit the electrical charge through the gel, and maintain a stable pH level to minimize any change that may occur. The buffer may also help with the extraction of DNA.

There are a number of buffers used for agarose electrophoresis, some of which include TAE and TBE. TAE contains a mixture of Tris base, acetic acid, and EDTA (Ethylenediaminetetraacetic acid), while TBE contains a mixture of Tris base, boric acid, and EDTA.

These buffers contain EDTA to inactivate many nucleases which require divalent cation for their function, providing good conductivity while producing less heat.

Power Supply

The power supply of your gel electrophoresis equipment can be just as important as your gels and buffers. There are various electrophoresis power supplies available for you to use, including

Automated Systems

Automated systems are an easy-to-use alternative to traditional gel electrophoresis instruments that provide an increase in throughput and a decrease in turnaround time.

Automated electrophoresis is best suited for a lab that wants to perform repetitive analyses, wishes to cut down on high labor cost, and has small amounts of precious samples to work with. The speed and convenience offered by an automated system that includes digital data storage for any recording is an important advantage to consider.

They incorporate DNA microfluidic kits and Chip (chromatin immunoprecipitation assay) systems for separation, sizing, and quantification of nucleic acids and proteins. The process is simplified so that minimal volumes of sample are required and results are produced in less than an hour, in contrast to manual processes that typically require substantial amounts of a sample and take over an hour to produce any results.

However, it should also be noted that being able to perform both manual and automated electrophoresis is a realistic approach for almost any laboratory, because each method offers specific advantages.

Gel Documentation System Leases to Fit Every Need

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Our lease agreements are founder-friendly and flexible, helping you preserve working capital, strengthen the cash flow of your business, and keep business credit lines open for expansions, staffing, and other crucial operational expenses and business development opportunities.

2-5 Year Lease Lengths

Leases range from 2 to 5 years. Length will depend on several factors, including how long you want to use the equipment, equipment type, and your company’s financial position. These are standard factors leasing companies consider and help us tailor a lease agreement to fit your needs.

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We don’t carry an inventory. This means you’re not limited to a specific set of manufacturers. Instead, you can pick the equipment that aligns with your business goals and preferences. We’ll work with the manufacturer of your choice to get the equipment in your facility as quickly as possible.

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Bundle preventive maintenance and repair coverage with your lease agreement. You can spread those payments over time. Easily maintain your equipment, minimize the chances something will break down, repair instrumentation quickly, and simplify your payment processes.

End-of-Lease Options

At the end of your lease, you have multiple options. You can either renew the lease at a significantly lower price, purchase the machine outright based on the fair market value of the original pricing, or call it a day and we’ll come the pick up the equipment for you free of charge.

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Our leases do not include loan-like terms, which can be restrictive or harmful in certain situations. We do not require debt covenants, IP pledges, collateral,  or equity participation. Our goal is to maximize your flexibility. When you lease with us, you’re collaborating with a true business partner.

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Our underwriting is done in-house. You can expect quicker turnaround, allowing you respond to your equipment needs as they arise. We require less documentation than traditional lenders and financiers and can get the equipment you need in operation more quickly.