The document discusses centrifugation and centrifuges. It explains that centrifugation uses centrifugal force to separate particles in suspension based on density by spinning samples at high speeds. It describes different types of centrifuges like microcentrifuges, high speed centrifuges, desktop centrifuges, and ultracentrifuges which vary in maximum speed and use. Clinical applications of centrifugation are also outlined, such as separating blood components and subcellular particles. Safety tips for operating centrifuges are provided.

1. Presentation By:
Sumit Kumar
Research Co-Ordinator
Department of Orthopaedic Surgery

4.  The centrifuge works on the principle of increasing
effective gravity to enhance the rate of settling of
suspended particles more dense than the buffer.
 We need to double the force on samples, increase the
rotation speed by 41%.
 After centrifuging, the liquid is called "supernatant“ and
the solids at the bottom of tube are called "pellet".

5.  Centrifugal force :-
 “A force, arising from the body's inertia, which to act
on a body moving in a circular path and is directed
away from the center around which the body is
moving.”

6.  FIXED ANGEL:-
Tubes are held at angle of 14 to 400 to the vertical.
Particles move radially outwards, travel a short distance.
Reorientation of the tube occurs during acceleration and deceleration
of the rotor.

7.  VERTICAL TUBE
Held vertical parallel to rotor
axis.
Particles move short distance.
Time of separation is shorter.
Disadvantage: pellet may fall
back into solution at end of
centrifugation.

8. Swing out to horizontal position when rotor accelerates.
Longer distance of travel may allow better separation,
such as in density gradient centrifugation.
Easier to withdraw supernatant without disturbing pellet.
Normally used for density-gradient centrifugation.
SWING BUCKET

9.  Work with speed- 8000- 13000 rpm
& RCF 10000g
 For rapid sedimentation of small
volumes (1-2 min)
Eg : Blood , Synaptosomes
 SMALL MICRO CENTRIFUGE
TYPES OF CENTRIFUGE

10.  HIGH SPEED CENTRIFUGE
 Maximum speed of 25000rpm, providing
90000g centrifugal forces.
 Equipped with refrigeration to remove
heat generated.
 Temperature maintained at 0-40C by
means of thermocouple.
 Used to collect microorganism, cell
debris, cells, large cellular organelles,
precipitates of chemical reactions.
 Also useful in isolating the sub-cellular
organelles (nuclei, mitochondria,
lysosomes)

11.  DESK TOP CENTRIFUGE
 Very simple and small.
 Maximum speed of 3000rpm
 Have temperature regulatory system.
 Used normally to collect rapidly
sedimenting substances such as blood
cells, yeast cells or bulky precipitates of
chemical reactions.

12.  ULTRA CENTRIFUGE
 Operate at speed of 75,000rpm,
providing the centrifugal force of
500,000g.
 Rotor chamber is sealed and evacuated
by pump to attain vacuum.
 Refrigeration system (temp 0-40C).
 Rotor chamber is always enclosed in a
heavy armor plate.
 Centrifugation for isolation and
purification of components is known as
preparatory centrifugation, while that
carried out with a desire for
characterization is known as analytical
centrifugation.

14. Three micro centrifuge tubes: 2 mL, 1.5 mL and 200 μL .
Screw-top micro-centrifuge tubes.

15. APPLICATION
In clinical laboratory, centrifugation is used to:-
 Remove cellular elements from blood to provide cell free plasma
or serum for analysis.
 Remove chemically precipitated protein from an analytical
specimen.
 Separate protein bound from free ligand in immunochemical and
other assay.
 Separation of the subcellular organelle, DNA, RNA.
 Separate lipid components.

16.  Ensure that centrifuge bowls and tubes are dry.
 Ensure that the spindle is clean
 Ensure that the rotor is properly seated on the drive shaft.
 Make sure that tubes or containers are properly balanced
in the rotor.
 Do not exceed the rotor’s maximum run speed.
 Close the centrifuge lid during operation.
 Make sure that the centrifuge is operating normally before
leaving the area.
 Make sure that the rotor has come to a complete stop
before opening the lid.