A sandwich-configuration electrochemiluminescence immunoassay based on Cu.sub.2O@OMC-Ru nanocrystals and OMC-MoS.sub.2 nanocomposites for determination of alpha-fetoprotein

A sandwich-format electrochemiluminescence (ECL) immunosensor has been developed for alpha-fetoprotein (AFP) detection based on the use of ordered mesoporous carbon-molybdenum disulfide (OMC-MoS.sub.2) as a sensor platform and cuprous oxide @ ordered mesoporous carbon-Ru(bpy).sub.3.sup.2+ (Cu.sub.2O@OMC-Ru) composites as signal tags. OMC alongside MoS.sub.2 plays a synergistic role in improving the electrochemical performance of the electrode in the electron transfer process. The uniform cubic-shaped Cu.sub.2O@OMC-Ru nanocrystals display excellent luminous efficiency, with a signal amplification strategy of OMC-MoS.sub.2 synergistic enhancement and Cu.sub.2O@OMC which is capable of immobilizing more Ru(bpy).sub.3.sup.2+ serving as a tracing tag to label antibodies. A detectable ECL emission at a Cu.sub.2O@OMC-Ru nanocrystals modified electrode is initiated at an applied voltage of +1.15 V (scanning range: 0-1.2 V), in the presence of the tripropylamine (TPA) as coreactant. With the increase in AFP concentration, the loading of Cu.sub.2O@OMC-Ru at the electrode increases. Afterward, the ECL detection of AFP shows a wide linear range from 0.1 pg/mL to 10 ng/mL with a correlation coefficient of 0.9964 and a detection limit of 0.011 pg/mL (S/N = 3) under the optimal experimental conditions. The recoveries were in the range 91.2-97.1% with RSD varying from 4.8 to 8.5%. Overall, the novel immunosensor has been successfully applied to the analysis of human serum samples, indicating a great potential for application in clinical diagnostics. Graphical abstract