Amperometric Immunosensor for Carcinoembryonic Antigen in Colon Cancer Samples Based on Monolayers of Dendritic Bipodal Scaffolds

Abstract

Detection of proteins that signal the presence or recurrence of cancer is a powerful therapeutic tool for effective early diagnosis and treatment. Carcinoembryonic antigen (CEA) has been extensively studied as a tumor marker in clinical diagnosis. We report on the development of an amperometric biosensor for the detection of CEA based on the immobilization of anti-CEA monoclonal antibody on a novel class of bipodal thiolated self-assembled monolayers containing reactive N-hydroxysuccinimide (NHS) ester end groups. The current variations showed a linear relationship with the concentration of CEA over the range of 0-200 ng/mL with a sensitivity of 3.8 nA x mL x ng(-1) and a detection limit of 0.2 ng/mL, which is well below the commonly accepted concentration threshold (5 ng/mL) used in clinical diagnosis. Real time and accelerated stability studies of the reporter antibody under various storage conditions demonstrated that the enzymatic activity and antibody affinity of the conjugate is retained for long periods of time in commercial stabilizing buffers such as StabilGuard Biomolecule Stabilizer, and a prediction of the stability trends was carried out using the kinetic and thermodynamic parameters obtained from the Arrhenius equation. The developed immunosensor as well as a commercially available enzyme-linked immunosorbent assay (ELISA) kit were successfully applied to the detection of CEA in serum samples obtained from colon cancer patients, and an excellent correlation of the levels of CEA measured was obtained. Ongoing work is looking at the incorporation of the developed biosensor into a platform for multiplexed simultaneous detection of several breast cancer related biomarkers.

Immobilized rolling circle amplification on extended-gate field-effect transistors with integrated readout circuits for early detection of platelet-derived growth factor

“…With an extendedgate area of 62 μm × 126 μm and a transistor size of W/ L = 18 μm/1 μm, the coupling coefficient was 0.85 for the EGFET with passivation. Our pilot study indicated that the potential change induced by the RCA process might reach the order of 150 mV at the polygate of the EGFET [34]. Therefore, no amplification of the EGFET signal was required.…”

Characteristics of a Bimetal-Layer Chip of a Surface Plasmon Resonance Sensor in the Intensity Interrogation for Tumor Marker Detection

“…Carcinoembryonic antigen (CEA) is known as a serum cancer biomarker associated with colon cancer, lung cancer, breast cancer, and other cancer in clinical tests [12,13]. Normal CEA Dept.…”

“…of Physics, Kyungpook National Unversity NS-1, 80 Daehakro, Bukgu, Daegu, 41566, Korea + level for healthy people lies between 3 ng/ml and 5 ng/ml, and the CEA level can increase up to 10 ng/ml due to other benign diseases. If the CEA level is over 20 ng/ml, then the cancer patients are considered to be in metastatic state [12,13].…”

A Sensitive Label-free Amperometric CEA Immunosensor Based on Graphene-Nafion Nanocomposite Film as an Enhanced Sensing Platform

“…The electrochemical immunosensor is an alternative approach for CEA determination with the advantages of low detection limit, fast response, simple design and ease of miniaturization. [4][5][6][7] The development of a simple and effective strategy for immobilizing bioreagents on or into the electrode is a crucial step in the design and fabrication of electrochemical immunosensors. Recently, graphene and its derivatives have attracted wide attention in the applications of nanoelectronics, biomedicines and biosensors because of their remarkable conductivities, large surface areas and strong adsorption abilities.…”