Electrochemical immunosensors for interleukin-6. Comparison of carbon nanotube forest and gold nanoparticle platforms

• Published in: Electrochemistry communications Vol. 11; no. 5; pp. 1009 - 1012
• Main Authors: Munge, Bernard S., Krause, Colleen E., Malhotra, Ruchika, Patel, Vyomesh, Silvio Gutkind, J., Rusling, James F.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.2009; Amsterdam Elsevier; New York, NY
• Subjects: Biological and medical sciences; Biosensors; Biotechnology; Cancer biomarker; Carbon nanotubes; Electrochemical immunosensor; Fundamental and applied biological sciences. Psychology; Gold nanoparticles; Host-tumor relations. Immunology. Biological markers; Medical sciences; Methods. Procedures. Technologies; Protein detection; Tumors; Various methods and equipments; Cancer biomarker; Carbon nanotubes; Electrochemical immunosensor; Protein detection; Gold nanoparticles; Human; Gold; Chemical analysis; Nanoparticle; Transition metal; Tumoral marker; Immunosensor; Electrochemical detector; Interleukin 6; Singlewalled nanotube; Biosensor; Amperometry; arbon nanotubes; Comparative study; Glutathione; Modified material
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2009.02.044

Electrochemical immunosensors based on single wall nanotube (SWNT) forests and 5 nm glutathione-protected gold nanoparticles (GSH-AuNP) were developed and compared for the measurement of human cancer biomarker interleukin-6 (IL-6) in serum. Detection was based on sandwich immunoassays using multiple (14–16) horseradish peroxidase labels conjugated to a secondary antibody. Performance was optimized by effective blocking of non-specific binding (NSB) of the labels using bovine serum albumin. The GSH-AuNP immunosensor gave a detection limit (DL) of 10 pg mL −1 IL-6 (500 amol mL −1) in 10 μL calf serum, which was 3-fold better than 30 pg mL −1 found for the SWNT forest immunosensor for the same assay protocol. The GSH-AuNPs platform also gave a much larger linear dynamic range (20–4000 pg mL −1) than the SWNT system (40–150 pg mL −1), but the SWNTs had 2-fold better sensitivity in the low pg mL −1 range.