Ultrasensitive electrochemical detection of cytokeratin-7, using Au nanowires based biosensor

Cytokeratin-7 (CK-7), a protein expressed in epithelial tissue, used to differentiate between types of cancers has been detected successfully by employing gold (Au) nanowires as a template for the enzyme immunoassay. Functionalized Au nanowires were used to enhance the sensitivity and selectivity of the cancer biomarkers detection. An enzymatic reaction between alkaline phosphatase enzymes with the p-nitrophenyl phosphate substrate resulted in an electroactive p-nitrophenol and redox active intermediate hydroquinone that has been detected electrochemically. A strong dependence of the anodic peak current with the concentrations of CK-7 resulted in detection down to 10 ng/mL concentration. Additionally, the cross-validation was assured using quantum dots-655 fluorescent markers.