Wireless sensor array based on DNA decorated single-walled carbon nanotubes for gas monitoring

Abstract

There is a growing interest in making sensors, optoelectronic and electronic devices with nanomaterials. Carbon nanotubes (CNTs) are unique materials due to their excellent electrical, mechanical and thermal properties, and also have good chemical stability. Single-walled carbon nanotubes (SWNTs) are formed by one atomic layer and have an extended π-bonding configuration. The conductivity of SWNTs is sensitive to trace amount of molecules or ions attached onto their surfaces. CNTs have exceptionally high sensitivity and fast response and were utilized in numerous chemical and biological sensing applications for environmental monitoring. One of the present problems with SWNT sensors is their nonselective response to many analytes. SWNTs networks were assembled onto the microelectrodes by a low temperature, low cost Dielectrophoretic (DEP) assembly process. SsDNA of different sequences were used to functionalize the nanotubes and improved their response to the gas vapors dramatically. To reduce the undesirable response of SWNTs to interfering analytes, a wireless nanosensor array with six channels each functionalized with different molecules were developed to measure the resistances of six SWNT sensors simultaneously during exposure to gases. The responses of different DNA decorated SWNTs and bare SWNTs to toxic organics were measured simultaneously and displayed by a GUI interface. Development of this wireless sensor array enabled real-time gas monitoring with various DNA functionalized SWNTs from a distance.