Single Cell Gel Electrophoresis and its Applications in Different Fields

The comet assay is also known as microgel electrophoresis (MGE) was first time established by Ostling and Johanson in 1984 for the direct exposure of DNA damage in individual cells [2]. First of all cells in a thin agarose gel on a slide (microscopic) were lysed then did electrophoresis and after that stained with a fluorescent DNA binding dye. The electric current pulled the charged DNA from the nucleus such that undisturbed and broken DNA fragments migrated further. The resulting images, which were subsequently named for their appearance as ‘comets’, were measured to determine the extent of DNA damage. The original method which was developed by Ostling and Johanson was not very good because they were unable to remove all of the proteins from the cells. So more lysis requires, for the removal of cellular proteins and for the migration of broken duplex in gel electrophoresis. Two laboratories changed the method about five years ago by applying different denaturing conditions for the measurement of Single strand breaks in DNA [2,3]. The first group (3) were maximized the sensitivity for the detection of small number of strand breaks, while second laboratory focused towards the detection of subpopulations which vary in drug or radiation sensitivity [2]. There has been greater interest in comet assay from past two to three years. Many papers publish on comet assay because it has very unique design for the direct determination of DNA damage in individual cells. Single cell gel electrophoresis also use to examine DNA repair by many experimental conditions (Table 1, Figure 1 & 2).