Benzofurazane has been attached to nucleosides and dNTPs, either directly or through an acetylene linker, as a new redox label for electrochemical analysis of nucleotide sequences. Primer extension incorporation of the benzofurazane-modified dNTPs by polymerases has been developed for the construction of labeled oligonucleotide probes. In combination with nitrophenyl and aminophenyl labels, we have successfully developed a three-potential coding of DNA bases and have explored the relevant electrochemical potentials. The combination of benzofurazane and nitrophenyl reducible labels has proved to be excellent for ratiometric analysis of nucleotide sequences and is suitable for bioanalytical applications.

Enzymatic construction of single-nucleobase redox-labelled oligonucleotides was developed either based on polymerase incorporation of a single modified nucleoside triphosphate (dNTP) followed by primer extension (PEX) with natural dNTPs or based on PEX with a biotinylated one-nucleotide overhang template, magnetoseparation and the second PEX with a full-length template.

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