Construction of Magnetic Core–Large Mesoporous Satellite Immunosensor for Long‐Lasting Chemiluminescence and Highly Sensitive Tumor Marker Determination

Abstract Chemiluminescence immunoassay exhibits high sensitivity and signal‐to‐noise ratio, thus attracting great attention in the early diagnosis and dynamic monitoring of diseases. However, the collection of conventional flash‐type chemiluminescence signal (<5 s) relies heavily on automatic sampling and reading instrument. Herein, a novel core‐satellite multifunctional chemiluminescence immunosensor is designed for the efficient enrichment and highly sensitive determination of cancer biomarker carcinoembryonic antigen (CEA) with enhanced and long‐lasting output signal that can be conveniently recorded by a simple microplate plate reading instrument. Anti‐CEA monoclonal antibody 2 (Ab2) modified Fe 3 O 4 @SiO 2 microspheres (Fe 3 O 4 @SiO 2 ‐Ab2, 370 nm in diameter) are synthesized as the core for selectively capturing and enriching target CEA in solution, and anti‐human CEA monoclonal antibody 1 (Ab1) and horseradish peroxidase (HRP) co‐immobilized dendritic large‐mesoporous silica nanospheres (MSNs‐HRP/Ab1, 80 nm in diameter, pore size: 17 nm) are synthesized as the satellite for efficient immunological recognition and signal amplification. The as‐designed core‐satellite magnetic chemiluminescence immunosensors exhibit a broad linear range of 0.01−20 ng mL −1 and a low detection limit of 3.0 pg mL −1 for the convenient, highly specific, and sensitive determination of CEA in human serum. Such core‐satellite chemiluminescence immunosensors are expected to act as a powerful tool for in vitro detection of various biomarkers, overcome the defect of conventional chemiluminescence relying heavily on expensive and bulky automatic instruments and popularize chemiluminescence analysis to primary medical institutions and remote areas.