Fabrication of a Colorimetric Carcino-Embryonic Antigen Sensor Using High-Activity DNAzyme as a Catalytic Label

Abstract

Detection of biomarkers in a biologically complex mixture remains a major challenge. Herein, an ultrasensitive colorimetric sandwich sensor for carcino-embryonic antigen (CEA) detection is introduced. The DNAzyme was tethered to biotinylated monoclonal antibodies (McAbs) which serve as the sensing element to recognize the target protein and was then introduced on to the CEA-McAbs assembled micro plate. The CEA was captured in a sandwich assay by the McAbs. The peroxidase-like DNAzyme catalyzed the oxidation of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), which generated a blue-green colorimetric signal. This method detected CEA in a serum-containing medium at a concentration as low as 10 nM. This strategy is a promising tool for bioanalytical and clinical applications.

Keywords:

• Cancer biomarker
• Carcino-embryonic antigen (CEA)
• Colorimetric sensor
• G-quadruplexes
• Immunoassay