Application and Research Progress of Rare Earth Element Labeling Technology in Immunoassay Detection

Rare earth elements (REEs), located in the IIIB group of the periodic table, can be detected in very small quantities by sensitive detection techniques. REE labeling technologies utilize fluorescent labeling, magnetic labeling, atomic fluorescence labeling, fluorescence resonance energy transfer (FRET) labeling and radiolabeling. Widely used immunoassays related to REE-labeled technologies include time-resolved fluorescence immunofluorescence assay (TRFIA), inductively coupled plasma–mass spectrometry (ICP–MS)-based immunoassays, mass spectrometry flow-through (CyTOF), and upconversion nanoparticles (UCNPs). REE-labeled immunoassays have been widely used in various fields, such as biological analysis, biomarker detection and analysis of food detection techniques, as these assays can use low quantities of biological tissue, exhibit stability, can label materials, lack radioactivity and show multidetection capability. To provide researchers with a deeper understanding of the immunoassay technique used to label rare earth elements, this paper reviews its labeling principle, detection technology, and application.