A novel electrochemical lung cancer biomarker cytokeratin 19 fragment antigen 21-1 immunosensor based on Si3N4/MoS2 incorporated MWCNTs and core–shell type magnetic nanoparticles

Abstract

Lung cancer is one of deadliest and most life threatening cancer types. Cytokeratin 19 fragment antigen 21-1 (CYFRA 21-1) is a significant biomarker for the diagnosis of non-small cell lung cancer (NSCLC). Due to these reasons, a novel electrochemical immunosensor based on a silicon nitride (Si₃N₄)–molybdenum disulfide (MoS₂) composite on multi-walled carbon nanotubes (Si₃N₄/MoS₂–MWCNTs) as an electrochemical sensor platform and core–shell type magnetic mesoporous silica nanoparticles@gold nanoparticles (MMSNs@AuNPs) as a signal amplifier was presented for CYFRA21-1 detection in this study. Capture antibody (Ab₁) immobilization on a Si₃N₄/MoS₂–MWCNT modified glassy carbon electrode (Si₃N₄/MoS₂–MWCNTs/GCE) was firstly successfully performed by stable electrostatic/ionic interactions between the –NH₂ groups of the capture antibody and the polar groups of Si₃N₄/MoS₂. Then, specific antibody–antigen interactions between the electrochemical sensor platform and the signal amplifier formed a novel voltammetric CYFRA21-1 immunosensor. The prepared composite materials and electrochemical sensor surfaces were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A linearity range of 0.01–1.0 pg mL⁻¹ and a low detection limit (LOD) of 2.00 fg mL⁻¹ were also obtained for analytical applications. Thus, the proposed immunosensor based on Si₃N₄/MoS₂–MWCNTs and MMSNs@AuNPs has great potential for medical diagnosis of lung cancer.