Electrical characterization of DNA molecules in solution using impedance measurements

Yi-Shao Liu, ECE, Purdue University
Padmapriya Banada, Purdue University
Shantanu Bhattacharya, Purdue University
Arun K. Bhunia, Department of Food Science, Purdue University
Rashid Bashir, Birck Nanotechnology Center and Bindley Bioscience Center, Purdue University

Date of this Version

April 2008

Citation

APPLIED PHYSICS LETTERS 92, 143902

This document has been peer-reviewed.

 

Abstract

We report on impedance measurements of fluids to examine the impact of the length and concentration of free-floating double-stranded DNA molecules. The impedance versus frequency characteristics were fitted to an equivalent circuit model including solution dielectric capacitance and conductance. The extraction of these parameters can be used to detect the presence of DNA molecules in the nanomolar range for a 400 bp long molecule. Our results show that the extracted dielectric capacitance and conductance increase with molecule length and concentration owing to a corresponding increase in number of molecule dipoles and counterions in solution.

 

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