Co Single-Atom Catalysts Boost Chemiluminescence.

: Co single-atom catalysts (SACs) with good aqueous solubility and abundant labelling functional groups were prepared in Co/Fe bimetallic metal-organic frameworks by a facile solvothermal method without high-temperature calcination. Different from traditional chemiluminescence (CL) catalysts, Co SACs accelerated decomposition of H2O2 to produce a large amount of singlet oxygen (1O2) rather than superoxide (•O2-) and hydroxyl radical (OH•). They were found to dramatically enhance the CL emission of luminol-H2O2 reaction for 1349 times, and therefore employed as very sensitive signal probes for conducting CL immunoassay of cardiac troponin I. The detection limit of the target analyte was as low as 3.3 pg/mL. It is the first time to validate employment of SACs for boosting CL reaction. The Co SACs can also be employed to trace other biorecognition events with high sensitivity.