Label-free detection of DNA hybridization based on poly(indole-5-carboxylic acid) conducting polymer

An electrochemical method to directly detect DNA hybridization was developed on the basis of a new conductive polymer, which was polymerized on the glassy carbon electrode with an indole monomer having a carboxyl group, indole-5-carboxylic acid (ICA). Hybridization with complementary, non-complementary and one-base mismatched DNA targets was studied by cyclic voltammetry (CV). Results showed a significant decrease in the current upon addition of complementary target. The change in peak current that was used as an index of sensor response was found to be linear with target concentration in the range of 3.34 × 10−9 to 1.06 × 10−8 M. The detection limit was 1.0 nM.