Carbon Nanotube Biosensors And Gas Sensors

Because of novel physical and chemical characteristics, carbon nanotubes are widely used as new sensing materials or modified materials .This paper mainly introduced the characteristic study of biosensors and gas sensors modified by carbon nanotubes.With large aspect ratio, carbon nanotubes have excellent biocatalysis. Modifying biosensor with Multi-walled carbon nanotube (MWNT) could raise the sensitivity and enlarge sensitive range of the sensor .MWNT were thought to enhance this response in the two sides. On one hand , after linking the FAD of glucose oxidase (GOD),MWNT accelerated the electron transfer .On the other hand, met the surface of the electrode, as a nanowire, MWNT expanded electrode space .Both of the situations could short the electron-transferring time and then increase the response current.As sensitive materials , carbon nanotubes could also be used as gas sensor. The good conductivity of this kind of gas sensor could get response current at milliamp level which were easily detected. MWNT possess good adsorption of gases. With the gas adsorption, the conductivity of MWNT changed. Adsorpting different gas led to different changing resistance. Non-modified MWNT were more sensitive to xylene vapor and toluene vapor etc than benzene and formaldehyde. MWNT modified by amidocyanogen shew good sensitivity to benzene and formaldehyde. Experiments proved that MWNT were more sensitive to former gases than single-walled carbon nanotube.