The difference between low electroosmosis agarose and standard agarose is the level of electroosmosis (EEO). Low electroendoosmosis agarose represents low electroendoosm, making it ideal for PCR analysis and preparative electrophoresis. General-purpose agarose, on the other hand, is used in conventional electrophoresis.

There are several different types of agarose available in the market, each with unique properties that make it suitable for specific applications. However, a common question is, what is the difference between standard molecular biology (MB) grade agarose and agarose LE (low electrical endoosmosis)? a standard molecular biology (MB) grade agarose and agarose LE (low electroendosmosis)?

The difference between agarose LE and standard agarose is the level of electroendoosmosis (EEO). Agarose LE stands for low electrical endoosmosis, making it ideal for PCR analysis and preparative electrophoresis. General-purpose agarose, on the other hand, is used in conventional electrophoresis.

For quick illustration, preparative electrophoresis refers to the purification of nucleic acids from agarose gels.

Figure 1. Example of preparative nucleic acid electrophoresis. DNA bands excised from agarose gels. Purified DNA can also be used for other downstream applications, such as ligation.

In the example in Figure 1, the DNA bands are extracted for purification, showing agarose gel as a preparatory step for DNA purification and subsequent applications.

While preparative electrophoresis is different from general analytical work, researchers can and often use both—first analyzing with agarose gels and then purifying nucleic acids for PCR, modification, ligation, and other techniques.

While it's helpful to understand the difference between agarose LE and multipurpose molecular biology grade agarose (general purpose agarose), you may have the following additional questions:

• What is Electroendoosmosis?
• Why is low electroosmotic agarose important?
• When will I choose agarose, and when will I choose multipurpose molecular biology grade agarose?
• Is there a moment when you need a higher level of electrical infiltration?
• What other types of agarose are there?

This article will answer questions one by one to help you gain information and confidence when choosing agarose and experiments.

What is electroendoosmosis?

Before discussing the deeper differences between agarose LE and other agaroses, it is necessary to explain the meaning of electroendoosmosis.

During electrophoresis, there is a layer of porous agarose gel in the buffer. When an electric current flows, liquid and DNA flow through the pores of the gel. This is important when interpreting electroendoosmosis in electrophoresis applications.

Electroosmosis refers to the flow of water and its contents in a porous material, when the charge is acted on – the positive and negative ion charges caused by the electric current.

Let's break it down briefly:

At the molecular level, agarose gel is a porous mesh material (see Figure 2) through which researchers distinguish fragment sizes through nucleic acids.

Figure 2 Diagram of the molecular structure of agarose, showing its porous properties.

When electrophoresis is performed, the gel is placed into a device and an electric current flows. On one side of the device is the positive electrode (anode). On the other side is the negative electrode (cathode). The current affects the movement of DNA, which carries a slight negative charge.

In addition to DNA, other components may also be ionized or carry a slight charge, including buffers or even sulfates (_SO42^-) bound to the agarose matrix.

Figure 3. Schematic diagram of _SO42^- negatively charged and bound to an agarose matrix. SO₄^2- content affects the electrical infragrance of the inner membrane.

SO₄^2- immobile when bound to agarose matrix; However, due to its negative charge, _SO42^- is still attracted to the anode (positive electrode).

At the same time, the water in the buffer is hydrolyzed (H⁺ + OH^-) during electrophoresis. Positive ions are attracted to the cathode side (negative ions).

Unlike negative ions immobilized in the gel matrix, positive ions can migrate to form resistance or countercurrent against the flow of DNA and other negatively charged particles.

Figure 4 Electroendoosmosis in agarose gels during electrophoresis. Positive ions in the buffer create resistance that affects DNA mobility.

From Figure 4, we can see that the negatively charged DNA fragment as well as the bound _SO42^- is attracted to the anode But ionized water and other positive ions in the buffer flow to the cathode, causing reverse flow. Imagine you are drifting down a river in an inner tube, following the current, while a jet ski in the opposite direction goes upstream. Its wake creates a countercurrent that begins to affect your movement down the current. This analogy may be a useful way to understand the resistance and effects of electrical in-osmosis.

Why is low electroosmotic agarose important?

Different levels of electroendoosmo are important for different approaches in molecular biology.

Low EEO agarose is a purer, lower sulfate content product. Sulfate, due to its negative charge, is a contributor to the phenomenon of electrical endoosmosis.

For nucleic acid purification and analysis, low electroosmolesis (low EEO) agarose improves mobility, separation, and resolution, as lower EEO reduces countercurrent resistance in electrophoresis.

Agarose LE (low EEO agarose) is suitable for fragments larger than 1 kb and can work with agarose concentrations between 0.8% and 2.0%.

In addition, agar LE is ideal for blotting methods.

The difference between agarose and agarose LE: in-depth scientific research

The difference between agarose LE and generic agarose is the degree of electroosmotonis during electrophoresis. LE agarose has low electroosmotic agarose, a property that allows for more uniform fragment movement with less obstruction to the gel.

In nucleic acid analysis or preparative electrophoresis, it is important to maintain more consistent movement in the gel.

Low EEO agarose contains lower sulfates, which reduces tension and backflow. By reducing the amount of countercurrent acting on nucleic acids, the fluidity and resolution of nucleic acids are improved, and the band deformation is reduced.

These factors optimize electrophoresis, making it more suitable for analytical and preparative work.

Table 1 below shows the typical EEO ranges for standard agarose, low EEO agarose, and high EEO agarose.

Table 1. Electroendosmosis ranges between low EEO agarose, standard agarose, and high EEO agarose.

Properties	Agarose LE	Agarose	Agarose HE
Typical EEO Range	0.07-0.13	0.12-0.15	0.23-0.27

One challenge when choosing low EEO agarose or choosing between standard agarose and low electrical osmotic agarose is that LE or low EEO characteristics are not always directly labeled.

By this we mean, the products you may see labeled molecular biology grade agarose. However, the characteristics of low EEO are not evident on the label or product specifications, depending on the product description or specifications.

Figure 5 Example of an agarose bottle label. EEO may be clearly stated, or must be found in product specifications, either on the label or on the supplier's website.

If electrical osmosis properties are important to your experiments, it is recommended that you carefully review the product description.

In some cases, the agarose you're looking at will be generic agarose. Some specifications or descriptions may indicate lower or higher electrical endoosmosis.

Bottle A in Figure 5 is an example of a bottle explicitly labeled as low EEO agarose. Bottle B does not have LE or low EEO in the product name, but the EEO content shown in the specification is considered low EEO. Bottle C is an example of all-purpose agarose. According to the listed EEO specifications, the EEO is slightly higher. While the image in the image lists the EEO on the bottle, it is up to the supplier whether the EEO specification is displayed on the label. If in doubt, we emphasize carefully reviewing the supplier's product pages and product descriptions.

Meibota sells low EEO agarose labeled as agarose LE (≤0.12). The agarose is also molecularly biology grade, meaning it is equivalent to an ultra-pure chemical and is ideal for molecular biology applications

When will I choose agarose LE and when will I choose multi-purpose agarose?

The decision to use lower, standard, medium, or higher EEO agarose depends on the composition of the electrophoresis, subsequent application, fragment size, and gel concentration.

Since low EEO agarose is a more purified agarose, it also reduces the impact of contaminants when the purified product is used in subsequent applications.

When considering which agarose to use, there are several questions to consider:

• Is electrophoresis performed on nucleic acids or proteins?
• Is this a regular gel, or will I do the analysis or follow-up application?
• What is the approximate size of the fragments I use? What is my gel concentration?

The choice of agarose is based on the electrophoresis object:

For nucleic acids (DNA and RNA), it is best to choose standard or low EEO agarose. In the following sections, we will explain in more depth when to choose multi-purpose agarose or LE agarose.

However, Table 2 provides a quick query to help you choose between All-Purpose Agarose (MP) or Agarose LE.

Agarose, which has high electropermeability, should be used when using electrophoresis to separate certain proteins, such as serum proteins, or when performing immunoelectrophoresis.

Table 2. Agarose choice based on what is being electrophoresed.

Properties	Agarose MP	Agarose LE	Agarose ME	Agarose HE
Nucleic Acids for Routine Gels	X	X
Nucleic Acids for Downstream Applications		X
Serum Proteins			X	X

Key: Agarose MP (multipurpose or general-purpose agarose), Agarose LE (low EEO agarose), Agarose ME (medium EEO Agarose), Agarose HE (High EEO agarose)

Nucleic acid electrophoresis for routine gels and analyses and subsequent applications:

When choosing between standard (multipurpose) agarose or agarose LE (low EEO) during DNA or RNA electrophoresis, it ultimately depends on your goals.

General-purpose (multi-purpose) agarose was selected for conventional nucleic acid electrophoresis. For analysis, inking, or other subsequent applications such as ligation, purification, and blotting, use low electrointernal osmosis (low EEO) agarose.

Low EEO agarose not only allows for higher resolution and band separation, but also contains fewer contaminants such as _SO4²-, making it more suitable for downstream work.

Approximate selection of agarose based on nucleic acid fragment size and gel concentration:

Table 3. Recommended agarose concentrations based on DNA size.

Concentration (%)	DNA Size (bp)
0.5	1,000 – 25,000
0.8	800 – 12,000
1.0	500 – 10,000
1.2	400 – 7,500
1.5	200 – 3,000
2.0	50 – 1,500

There is also a relationship between electroendoosmosis and agarose gel concentration. As the agarose gel concentration increases, so does the electroendoosmosis, as this increases the concentration of ionized functional groups that contribute to electroendoosmosis. This is an important consideration when deciding whether you need standard agarose or agarose LE.

Is there agarose that requires higher electrical endoosmosis?

Agarose with high and moderate electroosmolicity is necessary for certain protein applications such as electrophoresis of serum proteins. They can also be used for immunoelectrophoresis and anti-immunoelectrophoresis.

Due to the increased tension caused by electrointro countercurrent, different protein samples flow differently in the gel. This will help achieve better protein separation.

Serum proteins are a particularly good example because higher electropermeability allows for better separation of gama-globulin in serum.

What are the different types of agarose?

Common agaroses include all-purpose (multi-purpose) agarose; High, medium, and low EEO agarose; pulsed field gel electrophoresis agarose; high-resolution agarose; low melting agarose; etc.

List of common agarose types:

• • General or multipurpose agaroses (agarose MP)
  • Agarose LE (low EEO)
  • Agarose ME (medium EEO)
  • Agarose HE (high EEO)
  • Pulse field gel electrophoresis agarose
  • High-resolution agarose

In addition to this list, there are different grades of agarose, such as molecular biology-grade agarose options and agaroses that have been tested for genetic quality.

Different suppliers have also developed different varieties and specialties of agarose to meet unique needs.