The Electrochemical Detection of Interleukin-8, Cancer Biomarker, Based on a Gold Nanoparticle Platform and its Political Implications

Authors

Jaimee Doucette, Salve Regina UniversityFollow

Document Type

Article

Abstract

Herein we report on an ultrasensitive immunosensor based on glutathione protected gold nanoparticle (GSH-AuNP) for the electrochemical detection of interleukin 8 (IL-8), cancer biomarker in calf serum and proof of concept IL-8 detection in HNSCC cells. GSH-AuNP were bioconjugated to the primary antibodies (Ab1) and used to capture human IL-8 in a sandwich electrochemical immunoassay coupled to horseradish peroxidase enzyme labels. Using the optimized concentrations of the primary (Ab1) and secondary antibodies (Ab2), two sensor approaches were used to measure ultra low (≤ 500 fg mL-1) and elevated levels of IL-8. Biotinylated Ab2 bound to streptavidin HRP with 14-16 labels per antigen was used to measure high IL-8 concentration with a DL of 10 pg mL-1 (1.0 pM) in 10 L calf serum. The second approach greatly amplified the signal using 1 m magnetic beads coated with over 500,000 HRP labels providing the highest sensitivity of (1061.8 nA mL (fg IL-8)-1 cm-2 and the best detection limit of 1 fg mL-1 (100 aM) for IL-8 in 10 L calf serum. This represents a 10,000-fold and 30,000-fold decrease in the DL over the Ab-HRP(14-16) system and the industry standard ELISA for IL-8 respectively. The immuonsensors were also used to accurately measure IL-8 in HNSCC cell lines with excellent correlation to the standard enzyme linked immunosorbent assay (ELISA). These GSH-AuNP based immuonsensors show great promise for the fabrication of ultrasensitive biosensor microarrays for point-of-care cancer diagnosis.