Carbon nanotube amplification strategies for highly sensitive immunodetection of cancer biomarkers

ANYL 215

James F. Rusling, James.Rusling@uconn.edu1, Xin Yu, xin.yu@huskymail.uconn.edu1, Gary Jensen1, Joseph Gong1, Ashwinkumar Bhirde1, Bernard S. Munge, bernard.munge@salve.edu2, Voymesh Patel3, Fotios Papadimitrakopoulos, papadim@mail.ims.uconn.edu4, Sang-Nyon Kim4, and Silvio Gutkind3. (1) Department of Chemistry, University of Connecticut, U-60, 55 N. Eagleville Rd., Storrs, CT 06269-3060, (2) Department of Chemistry, Salve Regina University, 100 Ochre point Avenue, Newport, RI 02840-4192, (3) Oral and Pharyngeal Cancer Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD, (4) Nanomaterials Optoelectronics Laboratory, Polymer Program, Institute of Materials Science, Department of Chemistry, University of Connecticut, 97 North Eagleville Road, Storrs, CT 06269
Novel electrochemical immunosensors were made with single-wall carbon nanotube (SWNT) forests for highly sensitive and selective detection of cancer biomarkers in serum and tissue lysates. Greatly amplified sensitivity was attained by using bioconjugates featuring horseradish peroxidase (HRP) labels and secondary antibodies (Ab2) linked to carbon nanotubes (CNT) at high HRP/Ab2 ratio. Combining HRP-CNT-Ab2 bioconjugates with SWNT immunosensors resulted in a detection limit for prostate specific antigen (PSA) in 10 mL of undiluted calf serum of 4 pg mL-1 (0.1 fmol mL-1), a mass detection limit of 40 fg. Accurate detection of PSA in human serum samples was demonstrated by comparison to standard ELISA assays. PSA was quantitatively measured in prostate tissue samples for which PSA could not be differentiated by the gold standard immunohistochemical staining method. These easily fabricated SWNT immunosensors show excellent promise for clinical screening of cancer biomarkers and point-of-care diagnostics.
 

Honoring Joe Wang, Recipient of the Electrochemical Analysis Award
8:30 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 123, Oral

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006