Mediated amperometric immunosensing using single walled carbon nanotube forests
O'Connor, Máire B. and Kim, Sang Nyon and Killard, Anthony J. and Forster, Robert J. and Smyth, Malcolm R. and Papadimitrakopoulos, Fotios and Rusling, James F. (2004) Mediated amperometric immunosensing using single walled carbon nanotube forests. Analyst, 129 (12). pp. 1176-1180. ISSN 0003-2654
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A prototype amperometric immunosensor was evaluated based on the adsorption of antibodies onto perpendicularly oriented assemblies of single wall carbon nanotubes called SWNT forests. The forests were self-assembled from oxidatively shortened SWNTs onto Nafion/iron oxide coated pyrolytic graphite electrodes. The nanotube forests were characterized using atomic force microscopy and resonance Raman spectroscopy. Anti-biotin antibody strongly adsorbed to the SWNT forests. In the presence of a soluble mediator, the detection limit for horseradish peroxidase (HRP) labeled biotin was 2.5 pmol ml[-1] (2.5 nM). Unlabelled biotin was detected in a competitive approach with a detection limit of 16 nmol ml[-1] (16 μM) and a relative standard deviation of 12%. The immunosensor showed low non-specific adsorption of biotin-HRP (approx. 0.1%) when blocked with bovine serum albumin. This immunosensing approach using high surface area, patternable, conductive SWNT assemblies may eventually prove useful for nano-biosensing arrays.
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