Study on the\nElectrochemiluminescence Emission Mechanism\nof HOF-14 and Its Multimode Sensing and Imaging Application

A novel\nhydrogen-bonded organic framework (HOF-14) has attracted\nmuch attention due to its excellent biocompatibility and low toxicity,\nbut its research in the electrochemiluminescence (ECL) field has not\nbeen reported. In this work, the annihilation-type and coreactant-type\nECL emission mechanisms of HOF-14 were studied systematically for\nthe first time. It was found that the ECL quantum efficiency of HOF-14/TEA\ncoreactant system was the highest, which was 1.82 times that of Ru(bpy)<sub>3</sub><sup>2+</sup>/TEA. Further, the ECL emission intensity of\nHOF-14/TEA system could achieve colorimetric (CL) imaging of mobile\nphone. We also discovered that HOF-14 had superior photoelectrochemical\n(PEC) performance. Based on the above research results, a unique HOF-14-based\nmultimode sensing and imaging platform was constructed. The antibiotic\nEnrofloxacin (ENR) was selected as the detection target, and the Cu–Zn\nbimetallic single-atom nanozyme (Cu–Zn/SAzyme) with excellent\nperoxidase (POD)-like activity was used to prepare quenching probes.\nWhen the target ENR was present, Cu–Zn/SAzyme quenching probes\nwere introduced to the surface of HOF-14 by the dual-aptamer sandwich\nmethod. Cu–Zn/SAzyme could catalyze diaminobenzidine (DAB)\nto produce brown precipitations to quench the ECL, PEC, and CL signals\nof HOF-14, realizing multimode detection of ENR. This work not only\ndiscovered excellent ECL and PEC property of new HOF-14 material but\nalso systematically studied the ECL emission mechanism of HOF-14,\nand proposed a novel multimode sensing and imaging platform, which\ngreatly improved the detection accuracy of target and showed great\ncontributions to the field of ECL analysis.