Increasing Biosensor Sensitivity by Length Fractionated Single Walled Carbon Nanotubes

摘要: In this work the sensitivity increasing effect of single walled carbon nanotubes (SWCNTs) in amperometric biosensors depending on their average length distribution was studied. For this purpose the SWCNTs were oxidatively shortened and subsequently length-separated by size exclusion chromatography. TEM images of different fractions of SWCNTs were collected. Diaphorase embedded in an osmium redox polymer was blended with the shortened SWCNTs of different length. Depending on the average length of the SWCNTs the sensitivity of the amperometric biosensor model system towards oxidation of NADH could be increased up to a factor of five. The best performance could be achieved with SWCNTs of medium length. The linear range for NADH detection was between concentrations of 5 µM and 7 mM. The biosensor exhibited excellent electrocatalytic properties. Even at relatively high NADH …