Study on DNA detection using electrochemical method

Abstract

We report the new method for detection of DNA hybridization using enzymatic cleavage. The strategy is based on thst S1 nuclease is able to specifically cleave only single strand DNA, but not double strand DNA. The capture probe DNA thiolated single strand DNA labeled with eletroactive ferrocene group, was immobilized on a gold electrode. After hybridization of target DNA of complementary and noncomplementary sequences, nonhybridized single strand DNA was cleaved using S1 nuclease. The difference of enzymatic cleavage on the modified gold electrode was characterized by cyclic voltammetry and differential pulse voltammetry. We successfully applied this method to the sequence-selective discrimination between perfectly matched and mismatched target DNA including a single-base mismatched target DNA. Our method does not require eigher hybridization indicators or other exogenous signaling molecules which most of the electrochemical hybridization detection systems require. The ability to pattern a selective surface with different molecules has importance for molecular electronics and biotechnology applications, as well as for nanoengineering. For this, the patterning of many kinds of biomolecules as probes on the same solid surface is essentially required. Therefore, many research efforts have been focused on the thin film technology including self-assembly method. Most popular method to attach the various biomolecules on surfaces is to form the activating ester by EDC/NHS coulping reaction with carboxylic acid terminated surfaces. However, this method is time-consuming and has drawbacks in selective patterning. We have developed a new electrochemical method to pattern many biomolecules. This is based on electrochemically-induced and site-selective NHS patterning on self-assembled monolayer for subsequent covalent binding of biomolecules. We have studied potential-induced binding of different sequence DNA on microarrayed electrodes and characterized the modified su...