Separation of long DNA chains using non-uniform electric field: a numerical study

TL;DR

This study uses numerical simulations to explore how non-uniform electric fields can separate long DNA molecules in microchannels by analyzing their mobility and escape behavior influenced by electric traps and thermal fluctuations.

Contribution

It introduces a beads-spring chain model to simulate DNA migration in non-uniform electric fields and reveals how chain length and electric field amplitude affect separation efficiency.

Findings

Mobility sharply increases for chains longer than a critical length.

The critical chain length depends on the amplitude of the applied ac electric field.

Separation can be tuned without changing the microchannel structure.

Abstract

We study migration of DNA molecules through a microchannel with a series of electric traps controlled by an ac electric field. We describe the motion of DNA based on Brownian dynamics simulations of a beads-spring chain. Our simulation demonstrates that the chain captured by an electrode escapes from the binding electric field due to thermal fluctuation. We find that the mobility of chain would depend on the chain length; the mobility sharply increases when the length of a chain exceeds a critical value, which is strongly affected by the amplitude of the applied ac field. Thus we can adjust the length regime, in which this microchannel well separates DNA molecules, without changing the structure of the channel. We also present a theoretical insight into the relation between the critical chain length and the field amplitude.