Mediated amperometric immunosensing using single walled carbon nanotube forests.
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 microM) 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.
O'Connor
Máire
M
National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
Kim
Sang Nyon
SN
Killard
Anthony J
AJ
Forster
Robert J
RJ
Smyth
Malcolm R
MR
Papadimitrakopoulos
Fotios
F
Rusling
James F
JF
D000327:Adsorption; D000818:Animals; D000906:Antibodies / Q000032:analysis*; D015374:Biosensing Techniques; D004563:Electrochemistry / Q000379:methods; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D018625:Microscopy, Atomic Force; D037742:Nanotubes, Carbon; D013059:Spectrum Analysis, Raman
D000906:Antibodies; D037742:Nanotubes, Carbon