Duplex-immunoassay of ovarian cancer biomarker CA125 and HE4 based carbon dot decorated dendritic mesoporous silica nanoparticles

Fluorescent lateral flow immunoassay (FLFIA) is widely used mainly because of its low cost and instant detection. Its limit of detection (LOD) is closely related to fluorescence signals, and the development of fluorescence signals with fine performance remains a challenge. In this work, dendritic mesoporous silica nanoparticles (DMSNs) were used as fine carriers due to their large pore size and stable performance. We successfully synthesized carbon dots (CDs) with a 560 nm maximum emission wavelength (CD560) by the hydrothermal method. A new type of fluorescence signal for FLFIA was observed by loading CD560 on DMSNs through the Si-O bond which is denoted as DMSNs@CD560. Applying DMSNs@CD560 to the FLFIA can eliminate the influence of interfacial background blue fluorescence thus improving its detection sensitivity. The formed DMSNs@CD560-FLFIA achieved high sensitivity detection of ovarian cancer biomarkers carbohydrate antigen 125 (CA125) and human epididymal protein 4 (HE4). The LOD of CA125 is 0.5 U mL(-1) and the correlation coefficient R-2 = 0.985, and the LOD of HE4 reaches 0.05 ng mL(-1) and the correlation coefficient R-2 = 0.981. The DMSNs@CD560-FLFIA is sensitive and efficient providing a new method for the early diagnosis of ovarian cancer.

Automated summary

Fluorescent lateral flow immunoassay (FLFIA) is widely used for its affordability and quick detection. In this study, dendritic mesoporous silica nanoparticles (DMSNs) were utilized as carriers to synthesize carbon dots (CD560) for FLFIA. By loading CD560 on DMSNs through the Si-O bond, a new type of fluorescence signal, DMSNs@CD560, was created, which improved the sensitivity of FLFIA. The DMSNs@CD560-FLFIA achieved high sensitivity detection of ovarian cancer biomarkers CA125 and HE4, providing a new method for early diagnosis of ovarian cancer.