Nanoconfinement Effect and Nanozyme Catalysis Enhance ILu/HOF-14 Electrochemiluminescence for Biosensing

Abstract

A low collision frequency and an insufficient number of free radicals are the main problems leading to the low electroluminescence (ECL) efficiency of luminol and its derivatives. In order to solve the above issues, this work used nanoconfinement combined with nanozyme catalysis to significantly enhance the ECL efficiency. We assembled isoluminol (ILu) into the hydrogen-bonded organic framework HOF-14 and prepared a novel ECL emitter ILu/HOF-14 for the first time. Surprisingly, compared with the ILu/H₂O₂ system, the ECL signal of ILu/HOF-14/H₂O₂ was increased by 33 times. This was because the porous structure of HOF-14 effectively limited the movement of free radicals and increased their collision frequency. Therefore, the reaction rate between free radicals was significantly improved to achieve an ECL signal amplification. To further increase the number of free radicals, we introduced hybrid nanozyme Zn SAC@CuO₂ NPs with superior peroxidase (POD)-like activity. It could effectively catalyze the coreactant H₂O₂ to produce a large amount of ROS (OH^• and O₂^•–), accelerating the reaction rate of ILu with ROS and further improving the ECL signal. Based on the above research, a novel dual-mode biosensing and imaging platform was constructed to detect microcystin-LR (MC-LR). We used the nonspecific trans-cleavage activity of the CRISPR-Cas12a system to enhance the dynamic continuity and signal amplification capability of this biosensing platform, further improving the detection sensitivity and broadening the avenues of molecular diagnostic strategies.