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Journal of Nanotechnology
Volume 2012 (2012), Article ID 490175, 8 pages
Research Article

Targeting Antibodies to Carbon Nanotube Field Effect Transistors by Pyrene Hydrazide Modification of Heavy Chain Carbohydrates

1Fuzbien Technology Institute, 9700 Great Seneca Hwy, Rockville, MD 20850, USA
2MediSourcePlus, 222-22 Gurodong, Gurogu Seoul 336-708, Republic of Korea

Received 8 March 2012; Accepted 8 May 2012

Academic Editor: A. M. Rao

Copyright © 2012 Steingrimur Stefansson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Many carbon nanotube field-effect transistor (CNT-FET) studies have used immobilized antibodies as the ligand binding moiety. However, antibodies are not optimal for CNT-FET detection due to their large size and charge. Their size can prevent ligands from reaching within the Debye length of the CNTs and a layer of charged antibodies on the circuits can drown out any ligand signal. In an attempt to minimize the antibody footprint on CNT-FETs, we examined whether pyrene hydrazide modification of antibody carbohydrates could reduce the concentration required to functionalize CNT circuits. The carbohydrates are almost exclusively on the antibody Fc region and this site-specific modification could mediate uniform antibody orientation on the CNTs. We compared the hydrazide modification of anti-E. coli O157:H7 polyclonal antibodies to pyrenebutanoic acid succinimidyl ester-coated CNTs and carbodiimide-mediated antibody CNT attachment. Our results show that the pyrene hydrazide modification was superior to those methods with respect to bacteria detection and less than 1 nM labeled antibody was required to functionalize the circuits.