Types of Electrophoresis

Want to get a clear view of the different types of electrophoresis techniques? Then it is necessary to understand the electrophoresis principle. Electrophoresis is the process of separating the macromolecules present in a gel or fluid based on their binding affinity, size and charge under an electric field. It was Ferdinand Fredric Reuss who observed electrophoresis for the first time in 1807.

The primary classification of electrophoresis includes procedures like Anaphoresis and Cataphoresis. Anaphoresis is the electrophoresis of negatively charged elements called anions. On the other hand, Cataphoresis is the electrophoresis of cations or positively charged particles. The process has several uses in the analysis and separation of biomolecules like plasmids, proteins, nucleic acids, DNA and RNA.

Working Principle of Electrophoresis

Charged macromolecules placed in an electric field move in the direction of the positive or negative pole. The movement ultimately depends on the charge of the macromolecules. In this context, you should know that since nucleic acid is a negatively charged particle, it tends to move in the direction of the anode. The entire electrophoresis procedure has two varieties. They are capillary electrophoresis and slab electrophoresis. 

Proteins, if negatively charged, will move towards the anode and the cathode if they have a positive charge. Because smaller molecules migrate faster than the larger molecules, scientists can easily measure the travelled distance and make use of logarithms for determining the size of the particles.

Different Types of Electrophoresis

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The image depicts the types of electrophoresis. 

Modern-day electrophoresis devices come with supporting media. This supporting medium is a kind of physical support that helps in separating the charged macromolecules. This physical support renders two essential functions- molecular sieving and adsorption of taken macromolecules for separation. 

Some of the most commonly utilized supporting mediums include agar, agarose, starch and polyacrylamide. Based on the availability or unavailability of the supporting medium, the electrophoresis procedure is of two categories: Capillary electrophoresis and slab electrophoresis. 

Capillary Electrophoresis (CE)

Using this separation method, you can separate the charged particles with the help of their various migration rates in the electric field. It completely depends on size as well as charge of the particles. 

Slab Electrophoresis (SE)

It is a popular method for separating proteins. You can analyze many samples at a time using 1D format. Though CE needs specific instrumentation, SE needs nothing. 

These two types further can be divided into other types of electrophoresis techniques. In the capillary electrophoresis category, one can find techniques like paper electrophoresis and gel electrophoresis. 

Slab electrophoresis has additional sub-categories like zone electrophoresis, Isoelectrofocusing and Immunoelectrophoresis. 

We will be looking into the details of all these different types of electrophoresis below:

  1. Gel Electrophoresis

It is one of the most preferred electrophoresis procedures in the majority of the experimental environments. There are three essential varieties of gel electrophoresis. They are starch gel electrophoresis, polyacrylamide gel electrophoresis and agarose gel electrophoresis. In the starch gel electrophoresis procedure, potato starch granules are used in the form of a supporting medium. 

Things are different in the agarose gel electrophoresis technique. Here a wholly purified polysaccharide in large molecular mass is used as the support media. Polyacrylamide gel electrophoresis is one of the most common techniques due to its high stability. Also, it works on a large assortment of molecular concentrations.

  1. Paper Electrophoresis

The technique is quite simple. The sample intended to be separated applied on a strip of paper moisturized using a kind of buffer solution. There are separate tanks of this buffer solution, and each end of the paper is dipped in these tanks. Also, there is a different cathode or anode. Next, an electric current is applied. It forces the sample to move in the direction of the electrode with the opposite polarity. Once the procedure is completed, the paper is dried and then viewed using a sound quality detection system.

  1. Immunoelectrophoresis

The process is a blend of electrophoresis and immune-diffusion. The process involves placing antigen mixture into well cuts in gel without antibodies and separating their components through electrophoresis.

  1. Zone Electrophoresis

ZE or Zone electrophoresis is the process for the analyzation of nucleic acids, biopolymers and proteins. This electrophoretic separation procedure involves transporting different species in a buffer system under electric current. Because of differences in mobilities, these species will separate into well-resolved and varied peaks.

  1. Isoelectrofocusing

IEF or Iso Electrofocusing is the process of separating charged macromolecules, generally, peptides or proteins. The separation depends on their isoelectric point or the pH at which a particular molecule does not have any charge. This process works mainly because the macromolecules in the pH gradient tend to move towards their pI in an electric field. IPG strips consisting of acrylamide gel with wide pores for preventing sieving effects are used for the procedure.

FAQ (Frequently Asked Questions)

1. How Does the Electrophoresis Procedure Work?

During the electrophoresis procedure, an electric current is applied to macromolecules. Since the macromolecules are already electrically charged, it forces them to act upon the electric field. Molecules with higher charges will have more force applied on the part of the electronic field. 

Therefore, with the support medium in place, the macromolecule will be moving with its weight. A few good examples of the uses of the process of electrophoresis are RNA and DNA analyses. Protein electrophoresis is a medical process used for analyzing and separating the molecules that are d found in fluid samples which are mainly urine and blood samples.

2. What Happens in Case the Gel Electrophoresis Technique Takes too Long?

The process of gel electrophoresis is suitable for separating proteins or DNA based on their size. This process can even be used for separating mixtures, isolating them and for identifying molecules. Now, coming to the answer to the question of what happens in case the gel electrophoresis technique takes too long to complete? The probable answer to this question is that the sample used for the process might run out of the gel bottom.