A hierarchically porous microreactor based on imine-linked Ru–MCOF with extended π-conjugation and enhanced internal/external emitter excitation, which compresses the electron/co-reactant diffusion length and electrochemically activates luminophores, for ECL signal-off detection of cardiac troponin I (cTnI) that is an imperative biomarker for acute myocardial infarction, especially in the early diagnosis [70]. Here, TNNI3 is linked to myocardial infarction.