| Carbon nanotubes (CNTs), as a kind of novel one-dimensional structure materials, are characterized by unique mechanical and electrical properties. Commonly, CNTs aggregate into bundles. Specific sequences of single-stranded DNA (ss-DNA) and single-walled carbon nanotubes (SWCNTs) can self-assemble into stable complexes (SWCNT–DNA hybrids), which are dissolved in aqueous solution, under high-shear sonication. Preliminatry study shows that, compared with unmodified SWCNT, SWCNT-DNA possesses much better electrochemical properties.The SWCNT-DNA hybrids attach strongly on glass carbon (GC) electrode surface and easily form a uniform film, constituting a SWCNT-DNA modified electrode. Compared with unmodified and bundled SWCNTs modified GC electrodes, the SWCNT-DNA modified one shows strong current signals responding towards K3Fe(CN)6 solution in the cyclic voltammetric analysis. Moreover, such electrochemical signals are stable, of highly sensitive and respond to the concentration of K3Fe(CN)6 solution in a linear relationship. In the SWCNT-DNA hybrids, the wrapping of ssDNA around SWCNTs increases specific surface area of nanotubes and enhances the reversibility of the electrochemical reaction.Also, we describe the development and application of a new sensitive H2O2 sensor, utilizing a SWCNT-DNA modified GC electrode. Due to their large surface area and good electrical conductivity, the sensor exhibits high sensitivity and stability. The current is in a good linear relationship with the concentration of H2O2. The method is applied to the determination of H2O2 with satisfactory results. We also discuss the possibility of the electrode in detecting glucose, and find it difficult to immobilize GOD on the electrode through self-assembly. Regrettably, the response signals to glucose are not stable.These results show that, after the modification of DNA hybrid, SWCNTs modified GC electrode has a good detection performance, with a promising application in electrochemical sensors field.
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