Electrochemical Characterization of PNA/DNA Hybridized Layer Using SECM and EIS Techniques

Abstract

The detection of DNA hybridization is of significant scientific and technological importance as testified by the growing interest in chip-based characterization of gene expression patterns and detection of pathogens. Recently, there has been an increasing interest for DNA sensors based on the SAMs (Self Assembled Monolayers) of Peptide Nucleic Acid (PNA) modified electrodes. PNA is a DNA mimic that has a neutral peptide-like backbone with nucleobases that allows the molecule to hybridize to complementary DNA strands with high affinity and specificity. In this communication, we present hybridization studies with DNA target oligonucleotides on a mixed monolayer of PNA and MCH (mercaptohexanol) on Au electrodes using EIS (Electrochemical Impedance Spectroscopy) and SECM (Scanning Electrochemical Microscopy). Preliminary results of PNA/DNA hybridization detection in a label free approach are reported.