Electrochemiluminescence lateral flow immunosensor using luminol-labeled silver nanoparticles for highly sensitive and quantitative detection of cardiac troponin I.

Cardiac troponin I (cTnI) is a highly specific biomarker of cardiomyocyte injury, released during cell disintegration and necrosis, and is the gold standard for diagnosing acute myocardial infarction (AMI). At the onset of AMI, cTnI appears in very low concentrations (pg/mL level), necessitating the development of highly sensitive and rapid detection sensors. In this study, an electrochemiluminescence lateral flow immunosensor (ECL-LFI) was designed using luminol-labeled silver nanoparticles (luminol@AgNPs) for the sensitive and quantitative detection of cTnI. A screen-printed electrode (SPE) was integrated beneath the nitrocellulose (NC) membrane with plastic plates of the same thickness applied on both sides of the SPE to ensure a smooth flow surface. Upon addition of cTnI and the luminol-H2O2 system, sandwich immune complexes formed by antibody-functionalized luminol@AgNPs on the strips generated electrochemiluminescent (ECL) signals. The ECL-LFI exhibited a broad linear detection range from 5 pg/mL to 100 ng/mL, with a detection limit as low as 1.6 pg/mL. Additionally, the results show excellent correlation with clinical tests, demonstrating that the ECL-LFI provides a promising point-of-care tool for the early diagnosis of AMI and other diseases.