A Sandwich Electrochemical Immunosensor Using Magnetic DNA Nanoprobes for Carcinoembryonic Antigen

Abstract

A novel magnetic nanoparticle-based electrochemical immunoassay of carcinoembryonic antigen (CEA) was designed as a model using CEA antibody-functionalized magnetic beads [DNA/Fe3O4/ZrO2; Fe3O4 (core)/ZrO2 (shell) nano particles (ZMPs)] as immunosensing probes. To design the immunoassay, the CEA antibody and O-phenylenediamine (OPD) were initially immobilized on a chitosan/nano gold composite membrane on a glassy carbon electrode (GCE/CS-nano Au), which was used for CEA recognition. Then, horseradish peroxidase (HRP)-labeled anti-CEA antibodies (HRP-CEA Ab2) were bound to the surface of the synthesized magnetic ZMP nanoparticles as signal tag. Thus, the sandwich-type immune complex could be formed between secondary antibody (Ab2) modified DNA/ZMPs nanochains tagged by HRP and GCE/CS-nano Au. Unlike conventional nanoparticle-based electrochemical immunoassays, the recognition elements of this immunoassay included both electron mediators and enzyme labels, which obviously simplifies the electrochemical measurement process. The sandwich-type immunoassay format was used for online formation of the immunocomplex of CEA captured in the detection cell with an external magnet. The electrochemical signals derived from HRP during the reduction of H2O2 with OPD as electron mediator were measured. The method displayed a high sensitivity for CEA detection in the range of 0.008–200 ng/mL, with a detection limit of 5 pg/mL (estimated at a signal-to-noise ratio of 3). The precision, reproducibility, and stability of the immunoassay were good. The use of the assay was evaluated with clinical serum samples, and the results were in excellent accordance with those obtained using the standard enzyme-linked immunosorbent assay (ELISA) method. Thus, the magnetic nanoparticle-based assay format is a promising approach for clinical applications, and it could be further developed for the detection of other biomarkers in cancer diagnosis.

Study on the Diagnosis of Gastric Cancer by Magnetic Beads Extraction and Mass Spectrometry

“…An additional 10 healthy and 10 gastric cancer patients were used for external validation of the diagnostic model, and the sensitivity and specificity were up to 90%. CEA is glycosyl phosphatidyl inositol cell-surfaceanchored glycoproteins which are usually at very low levels in healthy adults and upregulated in many kinds of cancers [14,15]. CEA is usually used as a biomarker for many kinds of cancers, such as colorectal cancer [16,17] and gastric carcinoma [18,19].…”

“…CEA is glycosyl phosphatidyl inositol cell-surface-anchored glycoproteins which are usually at very low levels in healthy adults and upregulated in many kinds of cancers [ 14 , 15 ]. CEA is usually used as a biomarker for many kinds of cancers, such as colorectal cancer [ 16 , 17 ] and gastric carcinoma [ 18 , 19 ].…”

Tumor Targeting Strategies of Smart Fluorescent Nanoparticles and Their Applications in Cancer Diagnosis and Treatment

“…[163] Carcinoembryonic antigen (CEA) is a set of glycoproteins highly related to cell adhesion, which are normally produced during fetal development but stopped before birth. [164] Consequently, the CEA level is usually very low in healthy adults' blood but increased in some types of cancer, which means that it can be used as a tumor target in cancer targeting therapy. Tiernan et al [165] reported fluorescent dye-doped silica NPs and rare earth doped UCNPs conjugated with targeted anti-CEA Ab for cancer targeting imaging and therapy.…”

Electrochemical immunosensor for tumor necrosis factor-alpha detection in undiluted serum

“…Electrochemical ELISA has the added advantage of not being affected by particles, chromophores, and fluorophores that might be present in a sample and which might cause interference with optical detection. [9][10][11] However, a simpler method for developing a convenient, stable and sensitive electrochemical ELISA still requires significant research.…”