Question

1. We have a 1 cm long microfluidic channel where we have Ag/AgCI electrodes at the inlet and the outlet. We apply 1000 V to the left terminal and 0 V to the right terminal, with the intention that we want to separate DNA based on the mass to charge ratio. Assume buffer is low in salt concentration. a) Which direction would we normally expect the DNA to move towards, and why? b) Surprisingly, when we observe that the DNA moves in the exact opposite direction!! What could be going on?

Answer 1

Ans (a) DNA will move towards left terminal where 1000 V given, because phosphate groups in the DNA backbone carry negatively-charged oxygen molecules giving the phosphate-sugar backbone of DNA an overall negative charge.

And negative charge will move from lower potential to higher potential.

Ans (b)-

Electrophoresis following with pressure driven movement in that DNA moves opposite to pridicted one.

for more details study following to inhance knowledge about microcapallaries.

"Selective Trapping of DNA using Glass MicrocaMicrocapillaries" November 9,2018 .

Institute of computing physics.

Georg Rempfer,1, Sascha Ehrhardt,1 Nadanai Laohakunakorn,2, b) Gary B. Davies,1 Ulrich F. Keyser,2 Christian
Holm,1 and Joost de Graaf1, c)