Increasing amperometric biosensor sensitivity by length fractionated single-walled carbon nanotubes

Federico Tasca, Lo Gorton, Jakob Birkedal Wagner, Gilbert Nöll

    Research output: Contribution to journalJournal articleResearchpeer-review


    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. Transmission electron micrographs of different fractions of SWCNTs were collected. Diaphorase ``wired'' to an osmium redox polymer was blended with the shortened SWCNTs of different lengths. Depending on the average length of the SWCNTs the sensitivity of the amperometric biosensor model system towards oxidation of 1.4-dihydronicotinamide adenine dinucleotide (NADH) was increased by a factor of five. The best performance was achieved with SWCNTs of medium length. The linear range for NADH detection was between 5 mu M and 7 mM, the maximum sensitivity was 47 nA mu M-1 cm(-2), and the detection limit was 1 mu M. The biosensor exhibited excellent electrocatalytic properties. Even at relatively high NADH concentrations the oxidative current was limited by the diffusion rate of NADH. (C) 2008 Elsevier B.V. All rights reserved.
    Original languageEnglish
    JournalBiosensors and Bioelectronics
    Issue number2
    Pages (from-to)272
    Publication statusPublished - 2008

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