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Lerner MB , D'Souza J , Pazina T , Dailey J , Goldsmith BR , Robinson MK , Johnson ATC
Hybrids of a Genetically Engineered Antibody and a Carbon Nanotube Transistor for Detection of Prostate Cancer Biomarkers
Acs Nano. 2012 Jun;6(6) :5143-5149
PMID: WOS:000305661300064    PMCID: PMC3383883   
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Abstract
We developed a novel detection method for osteopontin (OPN), a new biomarker for prostate cancer, by attaching a genetically engineered single-chain variable fragment (scFv) protein with high binding affinity for OPN to a carbon nanotube field-effect transistor (NT-FET). Chemical functionalization using diazonium salts is used to covalently attach scFv to NT-FETs, as confirmed by atomic force microscopy, while preserving the activity of the biological binding site for OPN. Electron transport measurements indicate that functionalized NT-FET may be used to detect the binding of OPN to the complementary scFv protein. A concentration-dependent increase in the source-drain current is observed in the regime of clinical significance, with a detection limit of approximately 30 fM. The scFv-NT hybrid devices exhibit selectivity for OPN over other control proteins. These devices respond to the presence of OPN in a background of concentrated bovine serum albumin, without loss of signal. On the basis of these observations, the detection mechanism is attributed to changes in scattering at scFv protein-occupied defect sites on the carbon nanotube sidewall. The functionalization procedure described here is expected to be generalizable to any antibody containing an accessible amine group and to result in biosensors appropriate for detection of corresponding complementary proteins at fM concentrations.
Notes
Lerner, Mitchell B. D'Souza, Jimson Pazina, Tatiana Dailey, Jennifer Goldsmith, Brett R. Robinson, Matthew K. Johnson, A. T. Charlie Department of Defense U.S. Army Medical Research and Materiel Command[W81XWH-09-1-0205, W81XWH-09-1-0206]; NIH[CA06927]; National Science Foundation NSEC[DMR08-32802] This research was supported by the Department of Defense U.S. Army Medical Research and Materiel Command through grants W81XWH-09-1-0205 and W81XWH-09-1-0206. We acknowledge support of NIH Core Grant CA06927 (M.K.R.) and use of facilities associated with the Nano/Bio Interface Center, National Science Foundation NSEC DMR08-32802 (A.T.CJ.). 40 Amer chemical soc Washington 963yq