DNA-decorated carbon nanotubes for chemical sensing

We demonstrate a versatile class of nanoscale chemical sensors based on single-stranded DNA (ssDNA) for chemical recognition and single-walled carbon nanotube field effect transistors (SWNT FETs) for electronic read-out. SWNT FETs with a nanoscale coating of ssDNA respond to vapours that cause no detectable conductivity change in bare devices. The gases tested are methanol, trimethylamine, propionic acid, dimethylmethylphosphonate and dinitrotoluene. Sensor responses differ in sign and magnitude for different gases and can be tuned by choice of the ssDNA base sequence. Sensors respond and recover rapidly (seconds), and the sensor surface is self-regenerating. Preliminary results of all-atom molecular dynamics simulations are consistent with experiment.