A highly sensitive and specific fluorescent immunoassay for hepatitis B envelope antigen detection using AIE-encoded...

Developing highly sensitive, efficient, stable, and low-cost viral antigen detection strategies suitable for primary healthcare settings is of great significance for the early diagnosis and treatment of viral infections. Herein, we report a highly efficient fluorescent immunoassay strategy for the detection of hepatitis B envelope antigen (HBeAg) based on aggregation-induced emission (AIE) molecule-encoded fluorescent nanospheres. Three AIE luminogens (TPE-Br4, TPE-O2, and TPE-O3) were encapsulated into carboxyl-functionalized nanospheres via an ultrasonic swelling method, yielding uniform and well-dispersed multicolor fluorescent nanospheres. Among them, the red-emitting nanospheres, exhibiting superior photostability, were selected as signal output units. Anti-hepatitis B envelope antibodies were subsequently conjugated onto their surfaces to construct fluorescent nanobioprobes. By integrating these nanobioprobes with a sandwich-type enzyme-linked immunosorbent assay, specific capture and recognition of HBeAg were successfully achieved. The proposed method demonstrated a linear detection range of 0.01-1 ng mL^-1 and an ultra-low limit of detection (LOD) of 9 pg mL^-1. In addition, it exhibited excellent specificity and robust anti-interference performance in spiked fresh mouse serum samples. Overall, this work presents a sensitive, convenient, and cost-effective sensing platform for HBeAg detection, showing great potential for rapid and on-site screening of viral antigens in clinical applications.