Reasonable design of aggregation-induced emission luminogens for rapid detection of cardiac troponin I by lateral flow immunoassay

Aggregation-induced emission luminogens (AIEgens)-loaded nanoparticles (NPs) with unique optical properties have recently emerged as valuable tools in lateral flow immunoassays (LFIA). To further enhance the sensitivity and reliability of LFIA, there is an ongoing demand for fluorescent NPs exhibiting higher brightness. Herein, we developed an ultrabright AIEgens NPs-based LFIA for rapid and quantitative detection of the acute myocardial infarction biomarker, cardiac troponin I (cTnI). We introduced two para-CF₃-substituted benzenes (p-CF₃-Ph) groups into the traditional AIE structure to form (E)-4-(4-(bis(4′-(trifluoromethyl)-[1,1′-biphenyl]-4-yl)amino)styryl)-1-octadecylpyridin-1-ium (CF₃-TPA). The lipophilicity-improved CF₃-TPA was encapsulated into the hydrophobic cavities of polystyrene microspheres (PS), resulting in AIE_CF3NPs. Gratifyingly, the quantum yield (QY) of AIE_CF3NPs conjugated with antibodies (AIE_CF3NPs-mAb1) remained at 47.24 %, basically consistent with 48.68 % of AIE_CF3NPs, which guarantees the sensitivity of the strip. Additionally, the Stokes shift of AIE_CF3NPs reached 125 nm, effectively minimizing significant background fluorescence in the visible region. AIE_CF3NPs-labeled LFIA showed high sensitivity for cTnI detection in the range of 1–100 ng/mL, with a limit of detection (LOD) of 0.0897 ng/mL and a visible LOD of 10 ng/mL within 10 minutes, demonstrating high specificity and accuracy. Overall, AIE_CF3NPs has great potential as an effective tool for disease diagnosis in emergency situations.