centrifugation , its type,density gradient centrifugation and its type with advantages and disadvantages.

2. Introduction
• What is centrifugation?
• Centrifugation is a technique used for the separation
of particles from a solution according to their size,
shape, density, viscosity of the medium and rotor
speed. The particles are suspended in a liquid
medium and placed in a centrifuge tube. The tube is
then placed in a rotor and spun at a define speed.

3. Types of centrifugation
• There are three types of centrifugation:-
• 1. Density gradient centrifugation
• 2. Differential centrifugation
• 3. Ultra centrifugation

4. Density gradient centrifugation
• Definition: A method where the components of a
sample are separated on the basis of their
density, in a dense medium or density gradient, in
a centrifuge, according to the centrifugal force
they experience.
• Principle :- The principle is based on a decreasing
density of the suspending solution and migration
of the targets to the equilibrate portion of the
sample tube during centrifugation.

5. Generation of density gradients

6. Classification
• Density gradient centrifugation is classified
intro 2 types:-
• 1. Rate zonal centrifugation:- Rate-zonal
centrifugation is a centrifugation technique employed to
effectively separate particles of different sizes.
• 2. Isopycnic zonal centrifugation:- A method
where the components of a sample (e.g. DNA) are
separated on the basis of their density in a centrifuge
according to the centrifugal force they experience.

7. 1. Rate zonal centrifugation
• Rate-zonal centrifugation is
a centrifugation technique employed to
effectively separate particles of different sizes.
• The tube is first filled with different
concentrations of sucrose or another solute
establishing layers with different densities
and viscosities, forming a density gradient,
within which the particles to be separated are
added.
• The larger particles will be able to travel to the
bottom layer because they are more massive.
The greater mass allows the particles to travel
through layers with a greater viscosity, while
the smaller particles will remain at the top, as
they lack the mass to travel through the more
viscous layers.
• Once the centrifugation is over, fractions are
collected.

8. Application

9. Isopycnic Centrifugation
• Isopycnic Centrifugation
• In isopycnic centrifugation, using a
continuous gradient, a fairly
homogeneous population of organelles
will ‘band’ in the gradient at their actual
buoyant density over several hours.
• This method of separation is
independent of time, and relies solely on
the actual buoyant density of the
particle. Banded organelles or particles
can be recovered from the gradient by
subjecting it to fractionation (either by
punching a hole in the bottom of the
tube and draining it, or by taking specific
volumes of fractions from the top of the
gradient).
• If bands are visible, they may be removed
individually with a syringe with a long
needle.

10. Rate zonal centrifugation Vs Isopycnic
Centrifugation

11. Applications of density gradient
centrifugation

12. Thank you