Centrifugation and Ultracentrifugation

Introduction: 

The following article includes the basic concepts of centrifugation and ultracentrifugation. Both of these processes are very important in the field of science as well as in daily life. The basic principle on which these processes are based is sedimentation. As we all know, Sedimentation is the process of settling down sediments immersed in a liquid when left undisturbed for some time. The suspended material can be any particle, such as powder or clay. The particles are separated with the help of rotor devices known as centrifuges and ultracentrifuges. Further details of the two processes are provided in the article below.

What are Centrifugation and Ultracentrifugation?

Centrifugation can be defined as the phenomenon of separating liquids from solids or fluids of different densities by using a device called a centrifuge. This process is basically used in the precipitation of DNA, collection of cells, purifying virus particles, and distinguishing subtle differences in the conformation of molecules. One of the frequently employed and most useful techniques in the Molecular Biology Laboratory is centrifugation. 

On the other hand, ultracentrifugation uses a high-speed centrifuge to determine larger molecules’ molecular weights or separate colloidal and other small particles and determine their size.

Principles of centrifugation:

1. Centrifugation is purely based on the principle of sedimentation. Sedimentation is the process of settling down sediments immersed in a liquid when left undisturbed for some time. The suspended material can be any particle, such as powder or clay.

1. The separation of particles suspended in liquid media occurs either by a rotor in the centrifuge or tubes or bottles.

1. The central force separates particles of size five micrometre or less because they do not sediment under gravity. A simple filtration process separates the particles that are more than 5 micrometres. 

Principles of Ultracentrifugation:

1. Ultracentrifugation also takes place on the same phenomenon as centrifugation.

1. The primary basis for ultracentrifugation is also the sedimentation principle which states that the effect of gravity is less on the particles, which are less dense to settle much later than dense particles.

1. In ultracentrifugation, an additional force is applied to aid the sedimentation process because gravity takes more time to settle particles down.

1. The sample from which the particles need to be separated is rotated about an axis, resulting in a perpendicular force known as the centrifugal force. This force acts on different sample particles; the larger molecules move faster, whereas the smaller molecules move slower.

Objectives of Centrifugation and Ultracentrifugation:

1. The very basic objective of centrifugation and ultracentrifugation is to separate immiscible liquids.
2. In a supernatant liquid, the purification of the components takes place by these processes.
3. These processes are used in the processes of creaming and sedimentation to test the emulsion and suspensions at an accelerated speed.
4. The separation of crystalline drugs from the mother liquor takes place with the help of centrifugation and ultracentrifugation.

 Application of centrifugation: 

1. Centrifugation has a great role to play in chemistry labs. The evaluating process for various suspensions and emulsions takes place through centrifugation.
2. The production of drugs in bulk quantities is possible only because of centrifugation.
3. The production of many biological products is also backed by centrifugation.
4. Centrifugation can also be used to separate chalk powder from water. 
5. The process of stabilisation and clarification of wind takes place with the help of centrifugation.
6. The biopharmaceutical analysis of drugs is one such process that is backed by centrifugation. 
7. Used in the treatment of water.
8. The production of skimmed milk by removing fat from milk is also done through centrifugation. 

Application of Ultracentrifugation:

Ultracentrifuge is commonly used in cell biology, biochemistry, and molecular biology. Applications of ultracentrifuge include viral particles, lipoproteins, RNA and plasmid DNA, separation of small particles such as viruses, proteins or protein complexes, etc. Ultracentrifugation is divided into two: analytical and preparative. Analytical ultracentrifugation is used in the study of supramolecular assemblies or purified macromolecules. In contrast, preparative ultracentrifugation is used in the actual separation of subcellular components, tissues, cells, and other biochemically interesting particles.

Centrifugation Versus Ultracentrifugation:

Although the basic principle behind centrifugation and ultracentrifugation remains the same, the basic differences between these two techniques allow them to be used separately for different purposes. These differences primarily include the following:

1. Spinning Velocity:

There is a vast difference in the speed of the rotors of centrifuge and ultracentrifuge as they rotate. An ultracentrifuge rotor can spin as high as 1000000 x g, while the most common centrifuges have a relatively lesser speed. 

1. Refrigeration and Vacuum systems:

The presence of refrigeration and vacuum systems in ultracentrifuges differentiates them from centrifuges. Since the ultracentrifuges spin at a very high speed, there are many chances that the system or device may get damaged due to overheating and frictional force. However, in the case of centrifuges, these two systems are optional.

1. Type of pellet:

Pellet is something that is produced as a result of sample fractionation. The types of pellets or sediments produced in centrifugation and ultracentrifugation vary from each other because of the varying speeds of the rotors.

Conclusion:

In conclusion, the basic differences between centrifugation and ultracentrifugation are mentioned in the article. Not only in academic research but centrifugation and ultracentrifugation remain to be fundamental approaches in industry and the medical context as well. Both the processes will be accurate only if we know how to use the centrifuge and ultracentrifuge properly. Also, it is necessary to ensure the devices’ long-term functionality and keep the devices and samples user-safe. This article included a full-fledged discussion of the various concepts of centrifugation and ultracentrifugation, its differences, principles, and everything else. We have covered all the important aspects of both processes.