Trapping of 27 bp - 8 kbp DNA and immobilization of thiol-modified DNA using dielectrophoresis

TL;DR

This study investigates dielectrophoretic trapping and immobilization of various DNA fragments using nanoscale electrodes, combining experimental microscopy, simulations, and theoretical calculations to understand the trapping efficiency and DNA polarizability.

Contribution

It introduces a comprehensive approach integrating experiments, finite element simulations, and density functional theory to analyze DNA trapping and immobilization at the nanoscale.

Findings

DNA trapping efficiency depends on DNA length and electrode constriction size

Polarizabilities of DNA fragments vary with size and frequency

Immobilization of modified DNA on nanoelectrodes was successfully quantified

Abstract

Dielectrophoretic trapping of six different DNA fragments, sizes varying from the 27 to 8416 bp, has been studied using confocal microscopy. The effect of the DNA length and the size of the constriction between nanoscale fingertip electrodes on the trapping efficiency have been investigated. Using finite element method simulations in conjunction with the analysis of the experimental data, the polarizabilities of the different size DNA fragments have been calculated for different frequencies. Also the immobilization of trapped hexanethiol- and DTPA-modified 140 nm long DNA to the end of gold nanoelectrodes was experimentally quantified and the observations were supported by density functional theory calculations.