Electrochemical labeled DNA probe for the detection of sequence-specific DNA Original Research Article

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 (ipa) 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.