Metal-organic gel and metal-organic framework based switchable electrochemiluminescence RNA sensing platform for Zika virus

In this work, an ultrasensitive switchable electrochemiluminescence (ECL) RNA sensing platform was established based on metal-organic gel (MOG) and metal-organic framework (MOF) as electrode matrix and nanotag, respectively. The former was prepared via the in-situ loading of graphite-like carbon nitride (g-C3N4) and post-assembly of Au nanoparticles (AuNPs) within Zr-based MOG (AuNPs&g-C3N4@Zr-MOG), exhibiting highly efficient solid-state ECL. Fe-MIL-88 MOFs not only act as an ECL acceptor in ECL resonance energy transfer system but also have metal active centers to consume co-reactant, initiating double quenching effect on the ECL of AuNPs&g-C3N4@Zr-MOG. Then, DNA probe containing an apurinic/ apyrimidinic (AP) site connected the both, resulting in a turn-off signal. In the presence of the target RNA, the ECL was turned on because the AP site of DNA probe was activated to be circularly cleaved by endonuclease IV. Using Zika virus (ZIKV) RNA as a model analyte, the ECL platform showed a wide detection range from 0.3 nM to 3 μM with a detection limit as low as 0.1 nM. Besides, the sensor exhibited excellent specificity and stability, as well as acceptable real sample detection capability, illustrating the feasibility of clinical measurement in the future.