A persistent luminescent lateral flow immunoassay for rapid and accurate detection of estradiol in real samples

The demand for highly sensitive and reliable environmental monitoring methods has led to extensive research on new rapid detection technologies. Fluorescent immunochromatographic test strips are widely used for the detection of endocrine disruptors due to their advantages of rapid response, high sensitivity, and good selectivity. However, most current lateral flow immunoassay (LFIA) use excitation-dependent organic fluorescent molecules or quantum dots as signal label, which are susceptible to interference from background fluorescence in complex samples, thereby reducing their accuracy and sensitivity in real sample detection.

In this work, a novel immunochromatographic test strip was constructed for the anti-interference detection of endocrine disruptors in complex samples using persistent luminescent nanomaterials as signal units and antibodies for specific recognition of target molecule. The synthesized Zn₂GeO₄:Mn (ZGO:Mn) persistent luminescent nanomaterials possessed bright green luminescence after excitation turn off, allowing eliminate sample autofluorescence interference. As the proof-of-concept of this novel LFIA, estradiol (E2) was chosen as a model system to be investigated. After optimization, the persistent luminescent LFIA exhibited a good linear range from 0 to 15 μg/L with the limit of detection of 507 ng/L for E2, which are below the concentration range of E2 in most municipal wastewater systems. In addition, the persistent luminescent LFIA had strong specificity and high accuracy for E2 detection in water samples and milk samples.

This study introduces a persistent luminescent lateral flow immunoassay for E2 detection with minimized background interference. Significantly, this persistent luminescent LFIA has better detection performance than traditional fluorescent LFIA, showing tremendous potential for determination and control of E2 in real samples.