As a class of electrochemiluminescence (ECL) enhancers, silver-based materials have broad application prospects. In this work, a novel silver metal–organic framework (AgMOF) was developed as a self-enhanced ECL emitter by one-step mixing and standing at room temperature. The AgMOF could produce strong and stable ECL emissions based on a double-amplification method, which originated from the aggregation-induced ECL emission of ligands and catalyzing S2O8 2– to produce more SO4 •– by silver. Moreover, an ECL resonance energy transfer (ECL-RET) biosensor with AgMOF as a donor and BHQ2 as an acceptor was fabricated by duplex-specific nuclease (DSN)-assisted target recycling amplification to detect miRNA-107. The biosensor exhibited a strong ECL-RET effect due to the higher ECL emission of the AgMOF and perfect match of spectra between the AgMOF and BHQ2. Upon the introduction of DSN and target miRNAs, the specific DNA–RNA binding and nuclease cleaving could trigger the detachment of BHQ2, resulting in an increased ECL signal of AgMOF. Benefiting from the ECL-RET and DSN-assisted target recycling amplification methods, this biosensor achieved a wide linear relationship range from 20 to 120 fM with a low limit of detection (4.33 fM). This research presents an effective emitter for self-enhanced ECL systems, which broadens the potential ECL applications of silver-based nanomaterials.

Peroxynitrite (ONOO − ), a highly reactive nitrogen species (RNS) generated mainly in mitochondria, has been identified to be associated with numerous pathophysiological processes, and thus accurate ONOO − imaging with superior sensitivity and selectivity is highly desirable. Herein, we prepared a new type of carbon quantum dots (CQDs) with mitochondria-targeting function without the aid of any targeting molecules via a simple one-step hydrothermal route. The as-prepared CQDs not only displayed relatively uniform size distribution, few surface defects, high photostability, and excellent biocompatibility but also exhibited good selective fluorescence turn-off response toward ONOO − , owing to the oxidation of amino groups on the surface of carbon dots. A great linear correlation between the quenching efficiency and ONOO − concentration in the range from 0.15 to 1.0 μM with a detection limit of 38.9 nM is shown. Moreover, the as-prepared CQDs acting as a functional optical probe through a self-targeting mechanism were successfully applied for in situ visualization of endogenous ONOO − generated in the mitochondria of live cells, providing great promise for elucidating the complex biological roles of ONOO − in related pathological processes.

Cell signal transduction mediated by cell surface ligand‐receptor is crucial for regulating cell behavior. The oligomerization or hetero‐aggregation of the membrane receptor driven by the ligand realizes the rearrangement of apoptotic signals, providing a new ideal tool for tumor therapy. However, the construction of a stable model of cytomembrane receptor aggregation and the development of a universal anti‐tumor therapy model on the cellular surface remain challenging. This work describes the construction of a “multi‐catcher” flexible structure GC‐chol‐apt‐cDNA with a suitable integration of the oligonucleotide aptamer (apt) and cholesterol (chol) on a polymer skeleton glycol chitosan (GC), for the regulation of the nucleolin cluster through strong polyvalent binding and hydrophobic membrane anchoring on the cell surface. This oligonucleotide aptamer shows nearly 100‐fold higher affinity than that of the monovalent aptamer and achieves stable anchoring to the plasma membrane for up to 6 h. Moreover, it exerts a high tumor inhibition both in vitro and in vivo by activating endogenous mitochondrial apoptosis pathway through the cluster of nucleolins on the cell membrane. This multi‐catcher nano‐platform combines the spatial location regulation of cytomembrane receptors with the intracellular apoptotic signaling cascade and represents a promising strategy for antitumor therapy.

In this work, homo-FRET (Förster resonance energy transfer between the same kind of fluorophores) taken place in a hetero-FRET (FRET between two different fluorophores) systems can effectively improve the energy...