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

Abstract

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 R² = 0.985, and the LOD of HE4 reaches 0.05 ng mL⁻¹ and the correlation coefficient R² = 0.981. The DMSNs@CD₅₆₀-FLFIA is sensitive and efficient providing a new method for the early diagnosis of ovarian cancer.