Determination of Immunoglobulin E (IgE) in Serum by a Laboratory-Constructed Time-Resolved Fluorescent Nanosphere-Based Immunochromatographic Test Strip

Allergic diseases (AD) are significant and hence rapid and accurate immunoglobulin E (IgE) determination is critical for diagnosis and treatment. Herein, a rapid, sensitive, and quantitative immunochromatographic test strip was designed for assaying IgE in human serum based on laboratory-constructed time-resolved fluorescent nanospheres (LTRFNs) which have large specific surface areas and multiple carboxyl groups in the outer layer with efficient coupling to the antibodies. Using the stable fluorescence created by the LTRFNs, the test strip accurately quantified IgE for early diagnosis with a detection limit of 4.2 ng/mL. The test strip has a long working range from 8 to 1024 ng/mL, and excellent performance, including high sensitivity, good inter-batch repeatability, and stability. Furthermore, the analysis of 30 clinical serum samples showed good correlation with a commercial chemiluminescence protocol. Therefore, the laboratory-constructed test strip has potential as a novel tool for clinical diagnosis and a rapid home test for allergic diseases.