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Updated: May 5, 2026

A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis
Published on: September 10, 2014
Influence of DNA concentration on the interfacial electrode impedance
Sungbo Cho1, Younshin Oh, Sung-Min Ahn
1Department of Biomedical Engineering, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 406-799, Republic of Korea.
Abstract:
Sensitive and accurate DNA quantification is an essential step in most DNA analyses, especially in analysis of a small amount of DNA. Instead of typical DNA quantification methods (i.e., UV spectrometry, fluorometry, and quantitative polymerase chain reaction), electrical impedance spectroscopy has recently been investigated for label-free and efficient quantification of DNA. In this study, quantification of DNA in solution was investigated using electrical impedance spectroscopy without pre-processing, including the modification of the electrode surface and immobilization of DNA onto the electrode. The results showed that the measured impedance spectra were in agreement with a designed equivalent circuit model, and that the extrapolated parameters of interfacial electrode impedance were dependent on DNA concentration. The impedance measured at 1 and 10 kHz showed good correlation with DNA concentration (R2 > 0.95), with a dynamic range of detection from 0.01 pg/microl to 100 ng/microl. Based on the results, it is expected to utilize impedance spectroscopy for the real-time and label-free characterization of DNA concentration with high sensitivity and low operation cost.
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