Electrochemical detection of different types of single-base mismatches in DNA using copper-phthalocyanine tetrasulfonic acid

Abstract

In this manuscript, an electrochemical DNA hybridization biosensor which exploits long range charge transfer through double stranded DNA (ds-DNA) to copper-phthalocyanine tetrasulfonic acid - tetra sodium salt (CuPcS4) is described. Four negative charges of CuPcS4 make it a good choice to overcome two main problems of the biosensors: direct electron transfer with the electrode surface instead of charge transfer through DNA and positioning of the redox reporter before the mismatch position. The DNA recognition layer consisted of a self assembled monolayer of amino modified single stranded DNA (ss-DNA) on the surface of glassy carbon electrode (GCE). A significant increase of the peak current for CuPcS4 upon the hybridization process is observed. This biosensor can differentiate complementary target from non-complementary and also different types of single-base mismatch targets even thermodynamically stable G-A and G-T targets through diminution of voltammetric signal of CuPcS4. In addition, the position of the mismatch does not affect on the capability of the biosensor. © 2010 Elsevier B.V. All rights reserved.