Dual-mode lateral flow immunoassay based on gold nanoparticle-fluorescent microsphere nanocomposites for sensitive...

Ovarian cancer remains a highly lethal malignancy, primarily due to the lack of rapid and reliable early screening tools. Cancer antigen 125 (CA-125) is a key serum biomarker, but conventional immunoassays are either too complex for point-of-care use or lack sufficient sensitivity. Lateral flow immunoassays (LFIAs) offer speed and simplicity, but their sensitivity and reliability in complex matrices are often inadequate. Therefore, there is a clear need for a sensitive, robust, dual-readout LFIA platform for accurate CA-125 detection at the point of care.

We developed a novel dual-mode LFIA by integrating gold nanoparticles (AuNPs) with fluorescent microspheres (FMs) into a single nanocomposite (AuNP-FMs). This platform leverages surface plasmon resonance to amplify fluorescence while retaining a colorimetric readout. The assay achieves detection limits of 0.5 U/mL (fluorescence) and 1 U/mL (colorimetric) for CA-125 within 15 min, representing 10-fold and 20-fold improvements over single FM-based and AuNP-based LFIAs, respectively. It demonstrates high specificity, excellent reproducibility (RSD <6.6%), and reliable performance in human serum as well as clinical samples, thereby successfully distinguishing cancer patients from healthy individuals.

This work presents a sensitive and reliable dual-mode biosensor that overcomes the key limitations of traditional LFIAs. The synergy between the colorimetric and fluorescent signals enhances both the robustness and accuracy of CA-125 detection in clinical settings. The platform is cost-effective, portable, and readily adaptable for point-of-care ovarian cancer screening, demonstrating significant potential for clinical translation.