Novel Strategy To Prepare Fluorescent Polymeric Nanoparticles Based On Aggregation-Induced Emission Via Precipitation Polymerization For Fluorescent Lateral Flow Assay

Fluorescent polymeric nanoparticles (FPPs) attract much attention in the fluorescent lateral flow assay (FLFA) due to their favorable biocompatibility, excellent colloidal stability, and high detection sensitivity. However, conventional FPPs used in the FLFA suffer with aggregation caused quenching (ACQ) effect and complicated procedures for conjugating protein. Here, a novel strategy is developed for preparing the FPPs based aggregation-induced emission luminogens (AIEgen) through stabilized precipitation polymerization with maleic anhydride (MAH), styrene (St), AIE active TPE-1VBC as comonomers, which is initiated by 2,2-azobisisobutyronitrile (AIBN) in ethyl butyrate. Microenvironment alteration in the formation of FPPs is monitored by the self-reporting approach in a real-time manner, and effects of crosslinking on the alters are carefully investigated. With the merits of uniform and controllable sizes, high efficiency luminescence, and easy functionalized surface, the obtained FPPs is employed as the indicator for FLFA testing strips. Five FPPs with five sizes harvested from the polymerization are selected for studying the effects of particles' size on the flowing of FPPs in FLFA, which indicated that the FPPs with the diameter of 210 nm (FPPs@210) could be considered as the optimal FPPs for FLFA. Furthermore, the antibodies of COVID-19 were employed as the targets for demonstrating the feasibility of FPPs@210 for FLFA testing. This work provides a novel strategy to prepare ideal FPPs to construct FLFA strips, indicative of their great potential in bioassays.