Electrochemical labeled DNA probe for the detection of sequence-specific DNA

Abstract

An electrochemical labeled DNA probe for the detection of sequence-specific DNA is discussed. The denatured calf-thymus DNA was successfully labeled with the electrochemical active reagent ferrocenecarboxaldehyde (FCA) by 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC). This FCA labeled DNA probe is used to hybridize with the sample DNA sequence accumulated on the surface of a graphite electrode. Only the complementary sequence (cDNA) can form a double-stranded DNA (dsDNA) with the FCA labeled DNA probe. The anodic waves of the FCA bound to the double-stranded DNA (dsDNA) by differential pulse voltammetry (DPV) are used for the detection of cDNA. The anodic peak currents ( i pa) of FCA are related to the concentration of cDNA sequence between 1.0×10 −8 and 5.0×10 −6 mol l −1. The detection limit is 5×10 −9 mol l −1( S/ N=3). The probe showed high sensitivity and selectivity.