Centrifugation notes slideshare

Centrifugation notes...
Introduction of Centrifugation
History of Centrifugation
Principle of Centrifugation
Types of Centrifugation
Application of Centrifugation
Reference...

1. Centrifugation By Mahima Tyagi M.Sc. Biotechnology 1 st sem

2. CONTENT Introduction of Centrifugation History of Centrifugation Principle of Centrifugation Types of Centrifugation Applications of Centrifugation Reference

3. Introduction What is centrifugation? It is a technique which involves replication of centrifugal force to separate partical from a solution. According to their size, shape, density, viscosity of the median and rotor speed . What is centrifuge ? A centrifuge is a device that uses centrifugal force to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container , thereby separating fluids of different densities ( eg. Cream from milk ) or liquid from solids .

4. Cont. What is centrifugal force ? The apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation.

5. History In 1864, Antonin Prandtl ,who developed the first dairy centrifuge for the purpose of separating cream from milk. In 1869, Miescher used a crude centrifuge system to isolate a cell organelles. Svedberg in late 1920s developed first analytical ultracentrifugation . Technical refinement of the preparative centrifugation technique by Claude and colleagues in 1940s .

6. Basic principle of Centrifugation A centrifuge works by using the principle of sedimentation ( process of settling down) : under the influence of gravitational force ( g – force ) , substances separate according to their density. Different types of separation are known including isopycnic, ultrafilteration, density gradient, phase separation , and pelleting.

7. Cont. The rate of sedimentation depends upon applied centrifugal field being directed radiely outward and is determined by the formula G = w² r w = angular velocity of rotor rpm ( rotation per minute ) r = radial distance of particle from axis of rotation

8. Types of Centrifugation techniques There are two types of centrifugal technique for separating particles : Density gradient centrifugation Differential Centrifugation

9. Density gradient centrifugation Density gradient centrifugation is a technique in which macromolecules move through a density gradient until they find a density equal to their own. Density gradient centrifugation can further be divided into rate zonal and isopycnic centrifugation .

10. Rate zonal centrifugation In rate zonal centrifugation the solution have a density gradient. The sample has a density i.e greater than all the layers in the solution. The sample is applied in a thin zone at the top of the centrifuge tube on a density gradient. Under centrifugation force, the particles will begin sedimenting through the gradient. The particles will begin sedimenting in separate zones according to their size, shape and density.

11. Isopycnic centrifugation In this type of Centrifugation, the solution contains a greater range of densities. The density gradient contains the whole range of densities of the particles in the sample. Each particle will sediment only to the position in the centrifuge tube at which the gradient density is equal to it’s own density. In isopycnic centrifugation separation of particules occur into zones on the basis of their density differences, independent of time.

12. Differential Centrifugation Differential centrifugation is a common procedure in microbiology and cytology used to separate certain organelles from whole cells for further analysis of specific parts of cells . In the process, a tissue sample is first homogenized to break the cell membrane and mix up the cell contents. The homogenate is then subjected to repeated centrifugations, each time removing the pellet and increasing the centrifugal force .

13. Applications To separate two miscible substances . To analyze the hydrodynamic properties of macromolecules . Purification of mammalian cells . Fractionation of subcellular organelles (including membranes/membrane fractions) Fractionation of membrane vesicles . Separating chalk powder from water . Removing fat from milk to produce skimmed milk . Separating particles from an air-flow using cyclonic separation . The clarification and stabilization of wine . Separation of urine components and blood components in forensic and research laboratories . Aids in the separation of  proteins  using purification techniques such as salting out, e.g. ammonium sulfate precipitation .

14. References Principles and Techniques of biochemistry, Wilson and Walker, page no. 74-75, 86-87. Slideshare/Sanjay Sinhwar, phd. Research Scholar, department of zoology- kurukshetra university. Slideshare/Dr. Anurag Yadav, Assistant professor, MD Biochemistry and Consultant Biochemist . https://microbenote.com/centrifugation-Principle-types-and-applications/ https://en.m.wikipedia.org/wiki/Differential-centrifugation