Chemiluminescence enzyme immunoassay using magnetic nanoparticles for detection of neuron specific enolase in human serum

To detect a biomarker for small cell lung carcinoma, neuron specific enolase (NSE), a sensitive and specific chemiluminescence enzyme immunoassay was developed. Fluorescein isothiocyanate (FITC) labeled NSE capture antibody connected with NSE and alkaline phosphatase (ALP) labeled NSE detection antibody in a sandwich-type detection manner. This immune complex was further reacted with anti-FITC coated magnetic beads. In a magnetic field, the complex was enriched, and the sensitivity was thus enhanced. The limit of detection (LOD) of this method was <0.2 ng mL−1. The proposed immunoassay was highly selective, and not interfered by hook effect. The recovery was >83.0% and the coefficient of variation was <10.0%. Human sera from 120 patients were tested with the presented and traditional chemiluminescence enzyme immunoassay. An excellent linear relationship was obtained between two techniques. Overall, this immunoassay offers a promising alternative for NSE detection than traditional clinical examinations.

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► The FITC labeled NSE capture antibody and ALP labeled NSE detection antibody were prepared to develop a sandwich detection format.
► The immune complex formed in aqueous solution and then bound with anti-FITC immobilized magnetic beads for detection of NSE by chemiluminescence intensity.
► The presented method showed high sensitivity and satisfactory recovery and coefficient of variation.
► A linear relationship was obtained for detection results of 120 patients’ sera by the proposed method and traditional chemiluminescence immunoassay.