DNA Functionalized Single-Walled Carbon Nanotubes for Electrochemical Detection

Single-walled carbon nanotubes (SWNTs) were effectively dispersed and functionalized by wrapping with single-stranded DNA (ssDNA). The ssDNA−SWNTs attach strongly on glass substrate and easily form a uniform film, making it possible for electrochemical analysis and sensing. The film was fabricated into a working electrode, which exhibited good electrochemical voltammetric properties, such as flat and wide potential window, well-defined quasi-reversible voltammetric responses, and quick electron transfer for a Fe(CN)63-/Fe(CN)64 system, indicating that the ssDNA−SWNTs film should be a good analytical electrode for electrochemical detection or sensing. This was demonstrated by highly selective and sensitive detection of a low concentration of dopamine in the presence of excess ascorbic acid.