The combined detection of ovarian cancer biomarkers HE4 and CA125 by a fluorescence and quantum dot dual-signal immunoassay

Detection of the biomarkers human epididymis protein 4 (HE4) and cancer antigen 125 (CA125) is an important parameter for ovarian cancer diagnosis and follow-up. For this reason, our study aimed to develop an immunological detection method for simultaneous detection of multiple ovarian cancer biomarkers based on a dual-signal system. The dual-signal system consists of quantum dot nanospheres (QDNBs) and fluorescent nanoparticles (FNPs) that emit different wavelengths of fluorescence under different excitation light. The HE4 and CA125 detection antibodies were conjugated with FNPs and QDNBs to form signal complexes, which produce a signal proportional to the concentration of HE4 and CA125. This dual-signal immunoassay was applied to human serum samples to detect HE4 and CA125 levels and compare them using an electrochemiluminescence (ECL) assay. The linear range of the assay was determined to be 1.25-20 ng mL(-1) for HE4, and 9.4-200 U mL(-1) for CA125. Comparison of 25 human serum samples subjected to the ECL assay resulted in impressive correlation coefficients of 0.91 and 0.96 for HE4 and CA125, respectively. A quantitative method for detecting HE4 and CA125 was successfully established. Preliminary clinical sample analysis showed that the dual-signal immunoassay has a strong clinical value in the screening and diagnosis of ovarian cancer.