Enhancing Luminol Electrochemiluminescence by Combined Use of Cobalt-Based Metal Organic Frameworks and Silver Nanoparticles and Its Application in Ultrasensitive Detection of Cardiac Troponin I

Electrochemiluminescence (ECL) has been emerged as one of the most important methods for in vitro diagnosis and detec-tion, but it is still limited in sensitivity for ultrasensitive bio-detections. While fast and ultrasensitive detection of biomolecules is critical, especially for the clinical detection of cardiac troponin I (cTnI) for cardiac infarction diagnosis. In this study, an effective tactic was developed to enhance ECL efficiency of the luminol system, by combined use of Co2+-based metal or-ganic frameworks (MOF), zeolitic imidazolate frameworks (ZIF-67) and luminol-capped Ag nanoparticles (luminol-AgNPs). The integration leads to a pronounced ~ 115-fold enhancement in luminol ECL. Based on this fascinating sensing platform, a robust label-free ECL immunosensor was constructed for ultrasensitive detection of cTnI, the main marker of myocardial infarction, with good stability and a detection limit as low as 0.58 fg mL-1 (S/N=3).