Silver-amplified fluorescence immunoassay via aggregation-induced emission for detection of disease biomarker

Development of simple, robust, and reliable detection strategy of disease biomarkers holds tremendous promise for early clinical diagnosis and prognosis of diseases. In this work, through combining a silver nanoparticle (AgNP) linked immunoassay and aggregation induced emission (AIE)-based fluorogenic Ag⁺ probe, we developed a silver-amplified fluorescence immunoassay for the detection of disease biomarkers. This method overcame the intrinsic limitations of enzymes as the dissolution of AgNPs generated numerous Ag⁺, which could switch on the fluorogenic Ag⁺ probe driven by tetrazolate-Ag⁺ complexation. As a proof of concept, our method could be used for determining α-fetoprotein (AFP) with a linear relationship in concentrations ranging from 0.1 ng mL^-1 to 5 μg mL^-1 and a low limit of detection of 42 pg mL^-1. Our method was successfully confirmed for the detection of AFP in real serum samples from hepatocellular carcinoma (HCC) patients, demonstrating the great potential for clinical diagnosis.