In this work, a label-free electrochemical immunosensor was developed for the quantitative detection of carcinoembryonic antigen (CEA). Flower-like Ag/MoS2/rGO nanocomposites were employed as the signal amplification platform of the designed immunosensor for the first time. Due to the synergistic effect between molybdenum disulfide (MoS2), reduced graphene oxide (rGO) and Ag nanoparticles (NPs), Ag/MoS2/rGO nanocomposites could provide a high sensitivity for the label-free electrochemical immunosensor. The detection mechanism was based on the monitoring of the electrocatalytic current response change towards the reduction of hydrogen peroxide (H2O2) when immunoreaction occurred on the surface of the electrode modified with Ag/MoS2/rGO nanocomposites. Using amperometric i-t curve to record the electrocatalytic process, the proposed immunosensor achieved an ultrasensitive and specific detection of CEA with a low detection limit of 1.6 fg/mL. Under optimal conditions, the fabricated immunosensor exhibited acceptable reproducibility, selectivity and excellent stability. This designed immunosensor could provide an effective method in the clinical diagnosis of other tumor markers.

Label-free electrochemical immunosensor based on flower-like Ag/MoS2/rGO nanocomposites for ultrasensitive detection of carcinoembryonic antigen

Ultrasensitive photoelectrochemical immunoassay for CA19-9 detection based on CdSe@ZnS quantum dots sensitized TiO2NWs/Au hybrid structure amplified by quenching effect of Ab2@V(2+) conjugates.

A one-step electrochemiluminescence immunosensor preparation for ultrasensitive detection of carbohydrate antigen 19-9 based on multi-functionalized graphene oxide.

The linear no-threshold model is less realistic than threshold or hormesis-based models: An evolutionary perspective.

An ultrasensitive electrochemiluminescence (ECL) immunosensor for carbohydrate antigen 19-9 (CA19-9) detection using multi-walled carbon nanotube–platinum–luminol nanocomposites (MWCNT–Pt–luminol) as nanointerface and signal tags was designed. First, the MWCNT–Pt–luminol nanocomposite was decorated on the surface of a glassy carbon electrode (GCE) through the film-forming properties of chitosan (Chi). Then, the CA19-9 antibody (anti-CA19-9) was attached to the modified electrode surface via crosslinking with glutaraldehyde (GA). When CA19-9 was captured by its antibody immobilized on the immune platform via immunoreaction, the ECL signal intensity decreased. Under optimal conditions, the proposed ECL immunosensor showed excellent performance for CA19-9 ranging from 0.0001 U mL−1 to 10.0 U mL−1, with a detection limit of 0.000046 U mL−1 (S/N = 3) and a correlation coefficient of R = 0.9980. This is attributed to the fact that the MWCNTs–Pt nanomaterial has excellent conductivity and it could facilitate the decomposition of H2O2 to generate various reactive oxygen species (ROSs); thus, the ECL signals of luminol were effectively amplified and the sensitivity of the sensor was greatly increased. The prepared ECL immunosensor displayed simple, fast analysis, excellent stability, good reproducibility, and high specificity. Moreover, the developed ECL immunosensor provided satisfactory results in the determination of CA19-9 in real human serum samples.

Nazanin Mirzaei

Papers

The effect of high level natural ionizing radiation on expression of PSA, CA19-9 and CEA tumor markers in blood serum of inhabitants of Ramsar, Iran.