A dual-signal output electrochemical immunosensor based on Au-MoS/MOF catalytic cycle amplification strategy for neuron-specific enolase ultrasensitive detection.

In this work, a dual-signal output electrochemical immunosensor based on the Au-MoS/MOF high-efficiency catalytic cycle amplification strategy for the sensitive detection of neuron-specific enolase (NSE). The mixed-valence structure MOF (Fe/Fe-MOF) exhibits high-speed charge mobility and excellent electrochemical performance. Notably, nanoflowers-like MoS (MoS NFs), as a co-catalyst, were introduced into Fe/Fe-MOF to successfully ensure the stable cycle of Fe/Fe at the electrode interface. The constantly emerging of "fresh" active sites significantly amplified the current signal response. According to the electrochemical behavior, the catalytic cycle mechanism and electron transfer pathways between MoS and Fe/Fe-MOF were further discussed. The two output signals of a sample realized the self-calibration of the immunoassay results, which improved the reliability and sensitivity of the immunosensor. Under optimal conditions, the linear range was 1.00 pg/mL∼100 ng/mL, and the low detection limits were 0.37 pg/mL and 0.52 pg/mL. The results suggest that the as-proposed immunosensor will be promising in the biological analysis and early clinical diagnosis of cancer biomarkers.