The use of a flow-injection surface plasmon resonance (FI-SPR) spectrometer equipped with a bicell detector or a position-sensitive device for determining coordination of heavy metal ions (Cd(2+) and Hg(2+)) by surface-confined apo-metallothionein (apo-MT) molecules is described. To facilitate the formation of a compact MT adsorbate layer with a uniform surface orientation, MT molecules were attached onto a preformed alkanethiol self-assembled monolayer. The method resorts to the generation of apo-MT at the surface by treating the MT-covered sensor chip with glycine-HCl and the measurement of the apo-MT conformation changes upon metal ion incorporation. Domain-specific metal ion binding processes by the apo-MT molecules were observed. Competitive replacement of one metal ion by another can be monitored in real time by FI-SPR. The tandem use of an immobilization scheme for forming a sub-monolayer of MT molecules at the sensor surface and the highly sensitive FI-SPR instrument affords a low concentration detection level. The detection level for Cd(2+) (0.1 μM or 15 ppb) compares favorably with similar studies and the methodology complements to other well-established sensitive analytical techniques. The extent of metal incorporation by apo-MT molecules was also determined.
Hydrazine (N H ) is an important and commonly used chemical reagent for the preparation of textile dyes, pharmaceuticals, pesticides and so on. Despite its widespread industrial applications, hydrazine is highly toxic and exposure to this chemical can cause many symptoms and severe damage to the liver, kidneys, and central nervous system. As a consequence, many efforts have been devoted to the development of fluorescent probes for the selective sensing and/or imaging of N H . Although great efforts have been devoted in this area, the large number of important recent studies have not yet been systematically discussed in a review format so far. In this review, we have summarized the recently reported fluorescent N H probes, which are classified into several categories on the basis of the recognition moieties. Moreover, the sensing mechanism and probes designing strategy are also comprehensively discussed on aspects of the unique chemical characteristics of N H and the structures and spectral properties of fluorophores.
A sensitive and selective assay of DNA is developed by utilizing a signal transduction strategy with the rational redesign of the hairpin structured G-quadruplex molecular switch (G4-MS) assembled using auramine O (AO). By monitoring the changes of the fluorescent signal, we could identify and further quantitatively determine the target DNA in the samples.
Metal–organic frameworks (MOFs), as a class of crystalline hybrid architectures, consist of metal ions and organic ligands and have displayed great potential in luminescent sensing applications due to their tunable structures and unique photophysical properties. Until now, many studies have been reported on the development of MOF-based luminescent sensors, which can be classified into two major categories: MOF chemosensors based on reversible host–guest interactions and MOF chemodosimeters based on the irreversible reactions between targets with a probe. In this review, we summarize the recently developed luminescent MOF-based chemodosimeters for various analytes, including H2S, HClO, biothiols, fluoride ions, redox-active biomolecules, Hg2+, and CN−. In addition, some remaining challenges and future perspectives in this area are also discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.