Electrochemical Aptasensor for Determination of Mucin 1 by P-Aminophenol Redox Cycling

Abstract

Mucins, produced by epithelial tissues in most metazoans, have served as reliable molecular biomarkers for cancer diagnosis and prognosis. In this work, a competitive electrochemical aptasensor is reported for the determination of mucin 1 protein by p-aminophenol redox cycling. Specifically, the conjugates produced between biotinylated mucin 1 and streptavidin-alkaline phosphatase were captured by an anti-mucin 1 aptamer-modified electrode, which induced the production of electrochemically active p-aminophenol from the p-aminophenyl phosphate substrate. The resulting p-aminophenol was cycled by tris(2-carboxyethyl)phosphine after its oxidization on the electrode, thus enabling an increase in the anodic current. Because the mucin 1 competed with the conjugates to bind the anchored aptamer, the signal decreased with an increase in protein concentration between 0.5 and 6 nM. As a result, a detection limit of 0.1 nM was achieved. To demonstrate the viability of the method for real samples, the effects of glucose, blood serum, and other proteins (e.g., thrombin, human immunoglobulin G, and Zn₇-metallothionein) were investigated.

Keywords:

• Alkaline phosphatase
• Electrochemical aptasensor
• Mucin 1
• Redox cycling

ACKNOWLEDGMENTS

Zhiyong Wang and Ning Xia contributed equally to this work.

Notes

^a For mucin 1 peptide determination.

^b For mucin 1 protein determination.