Biophysics Project Report – 1st Year

Biophysics Project Report – 1^st Year

ELECTROPHORESIS

Arjun Ajithan 

Raghib Siddiqui

Alwin Sonny

Introduction

Electrophoresis is a wide-ranging term that defines the migration and separation of charged particles (ions) under the influence of an electric field. An electrophoretic system consists of two electrodes of opposite charge (anode, cathode), connected by a conducting medium called an electrolyte.

Principles of electrophoresis

 The separation effect on the ionic particles results from differences in their velocity (v), which is the product of the particle’s mobility (m) and the field strength (E):

1v=mE.

The mobility (m) of an ionic particle is determined by

• particle size
• shape
• charge
• temperature

 and is constant under defined electrophoretic conditions.

Electrophoretic conditions are characterized by the electrical parameters such as current, voltage, power and factors such as ionic strength, pH value, viscosity, pore size, etc., which describe the medium in which the particles are moving.

The removal of heat generated by the passage of electric current is one of the major problems in most forms of electrophoresis. Any temperature difference causes variations in the rates of migration through the medium, resulting in distortion in the bands of separated molecules. Clearly, it would be ideal if electrophoretic analyses could be carried out at a constant temperature.

Gel Electrophoresis

Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size. In gel electrophoresis, the molecules to be separated are pushed by an electrical field through a gel that contains small pores. The molecules travel through the pores in the gel at a speed that is inversely related to their lengths. This means that a small DNA molecule will travel a greater distance through the gel than will a larger DNA molecule.