A Reversible Nanolamp for Instantaneous Monitoring of Cyanide Based on an Elsner-Like Reaction

Abstract

It is well-known that cyanide ion (CN) is a hypertoxic anion, which can cause adverse effects in both the environment and living beings; thus, it is highly desirable to develop strategies for detecting CN, especially in water and food. However, due to the short half-life of free cyanide, long analysis time and/or interference from other competitive ions are general challenges for accurate monitoring of CN. In this work, through the investigation on the sequence-dependent optical interaction of DNA-CuNPs with the fluorophore (e.g., EBMVC-B), we found, for the first time, that DNA-CuNPs were an ideal alternative as fluorescence quencher in constructing a sensor which could be illuminated by CN based on an Elsner-like reaction and that the signal switching was dependent on poly(AT/TA) dsDNA sequence. By virtue of CuNPs' small size and its high chemical reactivity with cyanide, the lighting of fluorescence was ultrarapid and similar to the hairtrigger "turn-on" of a lamp, which is significant for accurately monitoring a target of short half-life (e.g., cyanide). Attributed to the unique Elsner-like reaction between CN and the Cu atoms, high selectivity was achieved for CN monitoring by the nanolamp, with practical applications in real water and food samples. In addition, because of the highly efficient in situ formation of DNA-CuNPs and the approximative stoichiometry between CN and Cu in the fluorescence switching, the nanolamp could be reversibly turned on and off through the alternate regulation of CN and Cu, displaying potential for developing reusable nanosensors and constructing optical molecular logic circuits.

Real-Time Visualizing Mitophagy-Specific Viscosity Dynamic by Mitochondria-Anchored Molecular Rotor

“…To reveal the truth, herein, we exploited a mitochondria-anchored molecular rotor, ethyl-4-[3,6-bis­(1-methyl-4-vinylpyridium iodine)-9 H -carbazol-9-yl)] butanoate (BMVC), as a molecular viscosimeter for real-time observation of mitochondria viscosity variation during mitophagy process in live cells. BMVC is a novel class of carbazole derivative possessing the distinct ability to bind DNA secondary structure and human serum albumin (HSA), and hence is the object of our investigations in G-quadruplex-based sensing, two-photon indicator for DNA conformation changes, and HSA-modulated fluorescence amplification. − In this work, we found that BMVC is a mitochondria-anchored viscosity-sensitive molecular rotor that allows for investigating changes in mitochondrial viscosity. The rotor units display a desirable off–on fluorescence sensitive toward the mitochondrial viscosity because of the free rotation restricted around the vinyl bond connecting the carbazol core and the pyridium group.…”

DNA-Templated Fluorescent Nanoclusters for Metal Ions Detection

“…Due to the extensive research and application of DNA-templated fluorescent NCs, their fluorescence properties have been extensively studied in recent years [1,5,8]. The DNA template shows significant effects on the fluorescence characteristics of NCs.…”

“…Fluorescent NCs are the well-defined sub-nanometer size structures that are formed by a few to a hundred metal atoms with high emission. Current fluorescent materials that are used in sensing applications mostly include organic fluorescent dyes, up-conversion nanomaterials, quantum dots, fluorescent proteins, et al The easy photobleaching and small Stokes shifts of organic fluorescent dyes restrict their applications in complex samples [8,9]. Most of quantum dots and up-conversion nanomaterials are physically large-size and potentially toxic, which limit their practical applications in biochemical analysis [10,11].…”

Determination of Cyanide in Water and Food Samples Using an Efficient Naphthalene-Based Ratiometric Fluorescent Probe

“…Additionally, cyanide fluorescent probes have been developed on the basis of the specific nucleophilic reactivity of cyanide to electrophilic double bonds, such as CC, CO, CN, CS, or CN + . Nevertheless, most of the reported fluorescent probes for determining cyanide in water samples and food samples only displayed fluorescence turn-on response. − A major limitation of the fluorescence turn-on probe is that the signal output is vulnerable to factors such as excitation intensity, probe concentration, and instrumental efficiency. By contrast, a ratiometric fluorescent probe can effectively eliminate the above-mentioned limitations and consequently provide more accurate analysis. , In addition, the preparation of the reported probes generally needs sophisticated synthesis procedures.…”