Ultrabright NIR AIEgen nanoparticles-enhanced lateral flow immunoassay platform for accurate diagnostics of complex samples

Accurate and sensitive near-infrared(NIR)luminescent lateralflow immunoassay(LFIA)has attracted considerable attention in thefield of point-of-care testing(POCT).However,the detection accuracy and sensitivity are often compromised by the lowfluorescence quantum efficiency of the NIRfluorescent probe.(<10%)Herein,ultrabright NIR AIEgen nanoparticles(PS@AIE830NPs)composed of polystyrene(PS)nanoparticles and NIR aggregation-induced emission luminogen(AIEgen)with the maximum emission at 830 nm(AIE830)is reported,and its poten-tial to promote an accurate and sensitive detection of complex samples by LFIA is described.The relative quantum yield(QY)of the PS@AIE830NPs was 14.76%,which was superior to that of the polymer embedding method and indocyanine green(ICG)-based NIR nanoparticles.The PS@AIE830NPs immunolabeled-LFIA com-bined with laboratory-built NIR-LFIA portable quantitative instruments(detected light range 800 nm)completely eliminated background interference and allowed>highly accurate and sensitive detection without any pre-treatment steps.The limits of detection(LODs)for aflatoxin B1(AFB1)in soy sauce,alpha hemolysin(Hla)of Staphylococcus aureus biomarker in jointfluid,and C-reactive protein(CRP)in human haemolysed samples were 0.01 ng mL-1,0.02µg mL-1,and 0.156 mg L-1,respectively,commensurating with those of the corresponding gold standard assays and covering the detection range of interests.It is anticipated that the ultrabright NIR AIEgen nanoparticles will serve as a universally applicable signal probe for NIR-LFIA diagnostics,promising to expand the range of applications for quantitative detection of complex samples.