Ultrasensitive electrochemical detection of neuron-specific enolase based on spiny core-shell Au/CuxO@CeO2 nanocubes

As a specific biomarker, neuron-specific enolase (NSE) is an essential clinical indicator for diagnosing small cell lung cancer. In this paper, a sandwich-type electrochemical immunosensor was designed for the quantitative detection of NSE. AuPt nanoblock spherical nanoarchitectonics (AuPt NSNs), a bimetallic nanoparticle with a rugged morphology, were utilized as the substrate, which could enhance the electronic conduction and increase the immobilization capacity of the primary antibody (Ab1). Moreover, through a simple hydrothermal method, Au/CuxO@CeO2 was prepared as a spiny core-shell nanocube with cerium dioxide (CeO2) and gold nanoparticles (Au NPs) loading. The combination of Cu2O, CuO, and CeO2 showed favorable catalytic activity toward hydrogen peroxide (H2O2). Furthermore, the deposition of Au NPs on the spiny surface structure enhanced the specific surface area and biocompatibility, thereby rendering it more effective for loading the second antibody (Ab(2)). As the label material, the Au/CuxO@CeO2 achieved signal amplification and sensitive detection with the immunosensor. Under optimal conditions, the designed immunosensor possessed a broad linear range of 50 fg mL(-1) to 100 ng mL(-1) and a limit of detection of 31.3 fg mL(-1), along with satisfactory performance in sensitivity, selectivity, and stability. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A sandwich-type electrochemical immunosensor was developed in this study for the quantitative detection of neuron-specific enolase (NSE) in small cell lung cancer diagnosis. The use of AuPt NSNs and Au/CuxO@CeO2 as substrates showed enhanced performance in terms of electron conduction, immobilization capacity, catalytic activity, and signal amplification, resulting in sensitive and effective detection of NSE. The designed immunosensor exhibited a broad linear range, low detection limit, and satisfactory sensitivity, selectivity, and stability.