Photoelectrochemical Immunosensor Based on a 1D Fe₂O₃/3D Cd-ZnIn_2.2S_y Heterostructure as a Sensing Platform for Ultrasensitive Detection of Neuron-Specific Enolase

Abstract

Lung cancer is a high-mortality cancer related to the concentration of neuron-specific enolase (NSE). In this work, a sandwich-type photoelectrochemical (PEC) immunosensor was constructed for ultrasensitive detection of NSE, which is based on iron trioxide/indium zinc cadmium sulfide (Fe2O3/Cd-ZnIn2.2S y ) as a sensing platform and Ag-modified polyaniline (Ag@PANI) as a signal amplification label. The 1D Fe2O3 porous nanorods with a large specific surface area were synthesized by calcination of Fe-MIL-88A and etching of NaOH. To improve the photocurrent response, the 3D architecture Cd-ZnIn2.2S y was combined with the 1D Fe2O3 porous nanorods to form a 1D Fe2O3/3D Cd-ZnIn2.2S y heterostructure. Specifically, the Fe2O3/Cd-ZnIn2.2S y heterostructure with a good energy level matching (the two can form a stepped energy level matching, which accelerates the transfer rate of electrons) can improve the separation efficiency of electron–hole pairs (e–/h+) under visible light irradiation, which enhances the photocurrent response. Ag@PANI has a strong electron transport capability and can be used as a secondary antibody marker for the signal amplification of the immunosensor. The sensor exhibits a good linear detection range of 100 fg/mL to 100 ng/mL with a low detection limit of 33.5 fg/mL. Moreover, the constructed sandwich-type PEC immunosensor shows good performance and possesses excellent specificity, selectivity, and stability over a period of 4 weeks for NSE detection. With these excellent properties, the immunosensor can be extended to analyze and diagnose other disease biomarkers.

Wireless Gold/Boron–Nitrogen-Codoped Graphene-Based Antenna Immunosensor for the Rapid Detection of Neuron-Specific Enolase

“…To date, many methods for detecting tumor markers have been established, such as fluorescence immunoassays, radioimmunoassays, chemiluminescence immunoassays, , and electrochemical and photoelectrochemical technologies. − However, these analytical methods have limitations such as complex operation, high cost, and low time consumption. Generally, immunoassay methods for tumor markers require 1–2 h to incubate antibodies (Abs) or antigens (Ags) on the sensor .…”

A magnetic plasma Fe3O4@Cu@Cu2O photoelectrochemical sensor for the detection of fumonisin B1

“…Most of the cancer patients die due to compression, extrusion, consumption or destruction, which gradually damages organ function until the body weakens or even fails. 1–3 Cancer has always been one of the greatest enemies of human health, 4–7 and therefore, the early diagnosis of cancer is crucial. There have been many detection methods for the detection of FB1, such as fluorescence detection, chemiluminescence detection, enzyme-linked assay, etc.…”

Label-Free Assessment of Neuron-Specific Enolase via Polydopamine over a Carbon-Nanotube-Based Flexible Immunosensor

“…Electrochemical techniques in conjugation with label-free immunosensors are of great interest due to their potential efficacy as specific, simple, and rapid detection techniques; more importantly, they reduce the time and cost of analysis, have no radiation hazards, and can be used for point of care detection (POCT). − However, the critical step in the fabrication of label-free immunosensors is the effective and stable immobilization of antibodies on the electrode surface. Therefore, the choice of substrate material plays a vital role in the fabrication of a multifunctional substrate that exhibits good electrochemical activity with ease of antibody immobilization. − A few reports based on noble metal nanoparticles (Au, Ag, Pd, Pt), carbonaceous materials and their composites, conducting and nonconducting polymers have been explored for the detection of NSE. − Most of them use a coupling agent, i.e., 1-ethyl-3-(3dimethylaminopropyl) carbodiimide N -hydroxy succinimide (EDC/NHS), for the immobilization of antibody. − However, the use of coupling agents and high-cost noble metal catalysts retard their implementation for clinical diagnosis. In the last few decades, carbon nanotubes (CNTs) have gained great attention in the development of electrochemical sensors owing to their exceptional physicochemical properties, strength, high electrical conductivity, easy protein immobilization, and retention of activity with enhanced electron transfer .…”