Label-free immunoassay based on chemiluminescence-functionalized magnetic mesoporous nanoparticles for rapid detection of neuron-specific enolase

Abstract

Lung cancer, as one of the cancers with the highest morbidity and mortality rates in the world, requires accurate detection of its vital serum marker, neuron-specific enolase (NSE), which is a key challenge for early detection of lung cancer. However, traditional chemiluminescence immunoassay (CLIA) methods rely on labeled antibodies (Abs) and suffer from complex operations and high costs. In this work, a label-free CLIA based on CL-functionalized mesoporous magnetic nanoparticles (CuFe₂O₄@mSiO₂-Cys-Luminol-Au NPs) is developed for the rapid and sensitive detection of NSE. The material combines the advantages of magnetic separation, mesoporous loading, catalytic enhancement, and biorecognition. CuFe₂O₄ NPs offer efficient magnetic separation, while the mesoporous silica (mSiO₂) layer is effectively loaded with luminol to amplify CL signals. L-cysteine (L-Cys) ensures the uniform distribution of luminol and gold nanoparticles (Luminol-Au NPs), with these Au NPs immobilizing Abs through Au–S and Au–N bonds, achieving high-density biocoupling. The constructed label-free CLIA enables highly sensitive detection of NSE without Abs labeling. The results show that the NSE concentration is linearly correlated with the CL intensity in the range 1.0 × 10⁻¹³ ~ 1.0 × 10⁻⁸ g/mL, and the detection limit is as low as 2.3 × 10⁻¹⁴ g/mL. The proposed method demonstrates excellent selectivity, stability, and anti-interference capability for the detection of NSE in human serum samples.

Graphical Abstract