moving with the higher speed while longer molecules take more time. In this
way separation can be done. If we attach a fluorescence molecule to the DNA
being separated, we can exactly get the count of number of molecules with a
particular size by counting the fluorescence. Figure2.25shows the schematic
of gel electrophoresis.
(b) Capillary Electrophoresis
Capillary electrophoresis method also shares the similar principle as that of
the gel electrophoresis. The only difference is that in case of gel electropho-
resis, there are kind of multiple capillaries (pores through gel) being used for
causing electrophoresis, while in case of capillary electrophoresis, there is
Fig. 2.24 Effect of uniform field on the various type of particles (positively charged particles,
neutral body)
Fig. 2.25 Gel Electrophoresis
2 Microfluidics Overview 63