AIE nanoparticle with enhanced fluorescence for ultrasensitive lateral flow immunoassays and point-of-care diagnosis of interstitial lung disease.

Krebs von den Lungen-6 (KL-6) has been recognized as an effective serum biomarker for interstitial lung disease (ILD). The KL-6 accurate detection is of great significance for evaluating the severity of ILD and the prognosis of patients. In this study, a bright aggregation-induced emission luminogen (AIEgen) N, N'-((1,2-diphenylethene-1,2-diyl)bis(4,1-phenylene))bis(N-phenylnaphthalen-1-amine) (TPETN) with a high quantum yield of 87.57% was designed and synthesized, which was subsequently encapsulated into polystyrene nanoparticles (PSNPs) for construction of ultrahigh fluorescent nanoparticle (TPNPs). The obtained TPNPs was found to be 128 times and 16 times higher sensitivity than traditional gold nanoparticles (AuNPs) and tetramethyl 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl) tetrakis([1,1'-biphenyl]-4-carboxylate) (TCBPE) embedded nanoparticles (TCNPs), respectively. Then, TPNPs were employed as signal output to construct a lateral flow immunoassay platform (TPNP-LFIA) for KL-6 detection. TPNP-LFIA achieved a limit of detection (LOD) of 0.0534 ng/mL, which was 77.15 times and 7.69 times lower than those of AuNP- and TCNP- based LFIA, respectively. The dynamic linearity of TPNP-LFIA for detecting KL-6 ranged from 0.15 to 333.33 ng/mL. The recovery rates of TPNP-LFIA in serum samples varied from 99.96% to 108.13%, with coefficients of variation ≤6.24%. Hence, TPNP-LFIA has promising potential as a rapid and quantitative method for detecting KL-6.