Bioactivity-protective electrochemiluminescence sensor using CeO2/Co4N heterostructures as highly effective coreaction accelerators for ultrasensitive immunodetection

In this work, an efficient bioactivity-protective electrochemiluminescence (ECL) sensor was developed for biomarker analysis. First, 3,4,9,10-perylenetetracarboxylic acid (PTCA) with stable ECL emission served as luminophores, and its non-toxic properties were conducive to the survival of biomarkers. Second, CeO2/Co4N heterostructures were developed as coreaction accelerators to realize multiple amplification of luminescence signal. Concretely, large amounts of sulfate radicals (SO4•-) were generated through the reversible conversion of Ce3+/Ce4+ redox pairs. Meanwhile, the aggregation defect of CeO2 nanoparticles (NPs) was alleviated with the introduction of Co4N nanowires, thereby improving catalytic efficiency. Furthermore, Co4N possessed good hydrogen evolution reaction (HER) characteristics, which promoted the ECL emission by enhancing the production of SO4•-. Third, the heptapeptide affinity ligand (HWRGWVC) was introduced to achieve the directional fixation of antibodies, thus protecting the bioactivity of the sensor and improving incubation efficiency of antibodies. In general, this study proposed a highly effective ECL enhancement mechanism, which provided the direction for the construction of highly bioactive and sensitive sensors.