Sensing charateristics of RNA oligomer coated SWNT gas sensors

In this paper, we investigated RNA base dependent gas sensing characteristics using single-stranded RNA (ss-RNA) decorated single-walled carbon nanotube (SWNT) devices. SWNTs were placed on to Au microelectrodes by a low temperature and low cost Dielectrophoretic assembly process. Four homo ribonucleic acid (RNA) sequences and four repeated RNA sequences were coated on to SWNTs and the corresponding changes in SWNT nanosensor behavior were explored. These RNA-SWNT devices function as Chemi-resistors where resistance change in response to vapors of methanol and IPA were measured. RNA decoration was found to improve the response of SWNTs to vapors of methanol and IPA significantly. The sensing response of homo RNA decorated SWNTs followed the trend: C >; G >; U >; A for methanol and G >; C >; U >; A for IPA. The sensing response of repeated base RNA coated SWNTs followed the trend: GU >; AG >; AC >; CU for methanol and GU >; AC >; AG >; CU for IPA. These dramatic differences in sensing characteristics of RNA-SWNTs provide new insights both to the binding affinities of RNA oligomers on SWNTs and to the formation of stable 3D structures by ss-RNAs on carbon nanotubes. These findings demonstrate a potential for controlling sensing specificity of RNA functionalized SWNT sensors for chemical and biological detection.