LAUSR

The application of nonconventional nonaromatic luminophores‐based hydrogels (NLHs) in bioanalysis is severely limited due to their luminescence in concentrated solution or solid state. Herein, a nonconventional NLH (B‐Au@PDMAA) with high signal‐to‐noise ratio and stability in dilute solutions is designed by enhancing nonaromatic luminophores intermolecular aggregation through bovine serum albumin‐gold nanoclusters (B‐Au) confined space interaction. Importantly, the established NLHs could be rapidly polymerized in situ on magnetic beads (MB) surface in dilute solutions, and the fluorescence intensity after polymerization is 5.63‐fold higher than that of direct polymerization. Moreover, proposed B‐Au@PDMAA@MB constructed homogeneous immunoassay platform is demonstrated to be highly sensitive for detecting hepatitis B surface antigen with a sensitivity of 3.39 ng mL−1, which is 28.6‐fold lower than that of B‐Au@PDMAA based immunoassay and comparable to the sensitivity of the chemiluminescence immunoassay. This work presents a new strategy for the synthesis of NLHs with high brightness and stability in dilute solutions, and opens new avenues for the construction of novel homogeneous immunoassay platforms.