An Aligned Carbon Nanotube Biosensor for DNA Detection

This paper reports the design and fabrication of a biosensor based on aligned single wall carbon nanotubes (SWCNTs) with integrated single-strand DNAs (ssDNA). This ultra-sensitive biosensor provides label-free real-time electronic detection of DNA hybridization between surface-immobilized ssDNA and target ssDNA. Hybridization kinetics between complementary and target ssDNA nucleotide base pairs result in a local charge generation between base pairs that is injected into the SWCNTs resulting in a detectable change in SWCNT electrical conductance. This conductance change is amplified electrically through the integration of the functionalized SWCNTs as the semi-conductive channel in a silicon-silicon oxide based field effect transistor (FET). Based on previous Langmuir DNA kinetics calculations, the projected sensitivity level of the SWCNT-DNA sensor is considerably higher than traditional fluorescent and hybridization assays.