Latest ArticlesUnder the public spotlight, uranyl (UO22+) ions has attracted considerable attention for the extreme radioactive and chemical toxicity to ourselves and our environment. Herein, we present a simple and effective ratiometric fluorescence imaging method for the visualizing and quantitative detection UO22+ ions by cellphone-based optical platform. The sensing solution was prepared by mixing label-free red carbon dots (r-CDs) and blue carbon dots (b-CDs) together with a fixed photoluminescence intensity ratio of 4:1. When UO22+ ions were added, the fluorescence of r-CDs can be selectively quenched, while the fluorescence of b-CDs remains stable without spectral changes. With the gradually increase the amounts of UO22+ ions, the different response of dual-color CDs resulted in a signification color evolution from deep red to dark purple under the ultraviolet (UV) light illumination. Then, a cellphone-based optical platform was constructed for directly imaging the color change of the samples, and the built-in Colorpicker APP quickly output the red, green and blue (RGB) channel values of these images within one second. Interesting, there was a linear relationship between the ratio of red and blue (R/B) channel values and UO22+ ions concentration from 0 μmol/L to 30.0 μmol/L (R2 = 0.92804) with the detection limit of ~8.15 μmol/L (signal-to-noise ratio of 3). In addition, the optical platform has also been applied to the quantification of UO22+ ions in tap water and river water sample. With the advantage of low-cost, portable, easy to operation, we anticipate that this method would greatly improve the accessibility of UO22+ ions detection even in resource-limited areas.
A ratiometric probe (HBT-HBZ) bearing 2-hydrazino benzothiazole and 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for sensing hypochlorous acid (HClO) with high selectivity and sensitivity is reported in this article. The fluorescence intensity ratios (I470 nm/I572 nm) of the probe with different concentrations of analyte showed excellent selectivity and a linear response to minor changes in HClO. The detection limit of 24 nmol/L suggests that the sensor is very sensitive to HClO. According to the series of performed experiments, HBT-HBZ has practical applications, such as the detection of HClO residues in tap water, which has been rarely reported. In addition, confocal laser microscopy experiments confirmed that HBT-HBZ can selectively recognize HClO in HeLa cells. A ratiometric probe (HBT-HBZ) for sensing HClO with high selectivity and sensitivity is reported in this article. The probe exhibited high selectivity for HClO among other ROS, RNS and anions. In addition, HBTHBZ has some practical applications such as the analysis of the HClO content in tap water. Furthermore, confocal fluorescence microscopy imaging showed that HBT-HBZ can be applied for detecting HClO in living cells.
Fluorescent probes have been widely employed in biological imaging and sensing. However, it is always a challenge to design probes with high sensitivity. In this work, based on rhodamine skeleton, we developed a general strategy to construct sensitivity-enhanced fluorescent probe with the help of theoretical calculation for the first time. As a proof of concept, we synthesized a series of HOCl probes. Experiment results showed that with the C-9 of pyronin moiety of rhodamine stabilized by an electron donor group, probe DQF-S exhibited an importantly enhanced sensitivity (LOD: 0.2 nmol/L) towards HOCl together with fast response time (< 10 s). Moreover, due to the breaking symmetrical electron distribution by another electron donor group, the novel rhodamine probe DQF-S displayed a far red to near-infrared emission (>650 nm) and large Stokes shift. Bioimaging studies indicated that DQF-S can not only effectively detect basal HOCl in various types of cells, but also be successfully applied to image tumor tissue in vivo. These results demonstrate the potential of our design as a useful strategy to develop excellent fluorescent probes for bioimaging.
Cysteine (Cys) plays an important role in regulating cellular redox balance. But due to the constant changes in the concentration of Cys in organisms, fast response sensors are urgent required for practical application. In this work, a fluorescent probe with a fast response was developed by linking coumarin derivatives containing α, β-unsaturated ketones to NBD. The PET effect made the system non-fluorescent. When the probe reacted with Cys, the bond between the coumarin derivative and the NBD was cut off, meanwhile a rapid rearrangement and reactive site passivation occurred. Then two fluorophores with the same emission peak are released, among them, strong fluorescence signal of NBD dominated. Thus, although the similar reaction occurred for Hcy, the rate of NBD derivative rearrangement was slow, in a short time, fluorescence signal was still weak. As for GSH, cleavage could occur, but no rearrange within the NBD molecule due to GSH with large volume. Because of strong fluorescent emission, this probe was successfully used in biological imaging about cell and zebrafish. More importantly, the probe was successfully used to evaluate the oxidative stress caused by copper(II) in living cells. This fluorescence strategy and application will provide a new way of studying intracellular oxidative stress processes and damage.
Polymorphism makes it possible to clarify the relationship between emission property and crystal structure. However, based on the exact molecular conformation in tetraphenylethene polymorphisms, it is still challenging to evaluate the difference of intramolecular coplanarity without the support of calculation because of the complex combination of four different torsion angles between four peripheral benzenes and the central ethylene plane. Here, by using a di-formyl-functionalized tetraphenylethene derivative, two ideal polymorphisms with a consistent trend of the corresponding torsion angles have been obtained. For the first time, we explicitly demonstrated that intramolecular coplanarity is the underlying cause of the polymorphism-dependent emission of tetraphenylethene derivatives.
Three fluorescent BINOL-Si complexes (FS1, FS2 and FS3) were rationally designed and synthesized to detect diethyl chlorophosphate (DCP), a mimic of lethal nerve agents. These three fluorescent probes showed green, yellow and orange fluorescence, respectively. Moreover, the series of fluorescent probes has the characteristics of fast response time (≤4 s), low detection limit (0.0097 μmol/L), high sensitivity and naked eye detection. More important, a fiber optic sensor capable of detecting DCP vapor in real time was also prepared for the first time, the lowest detection limits (down to 4.4 ppb) were all lower than that of the IDLH (immediately dangerous to life or health) concentration of Sarin (7.0 ppb).
For efficient and quantitative DNA detection, fluorescence staining is the most often explored approach, which relies on non-covalent binding of dyes with double stranded DNA (dsDNA). Ethidium bromide (EB) is the most classic DNA stain, but suffers from its high carcinogenicity. A series of less toxic alternatives were developed, many of which contain the core structure of the benzothiazole ring. However, the relationship between the structure and the DNA detection performance was not illustrated. Herein, five benzothiazole dyes, namely thiazole orange, SYBR Green Ⅰ, PicoGreen, SYBR Safe, and thioflavine-T, were compared for DNA detection through direct fluorescence and gel electrophoresis, with particular focus on the structure-performance relationship. It turned out that SYBR Green Ⅰ is currently the best choice for DNA detection. The results in this work may be useful for future DNA-staining dye developments.
In this study, α-Bi2O3/g-C3N4 nanocomposite with direct Z-scheme was successfully prepared through calcination of BiOCOOH/g-C3N4 precursor at different temperature. Meanwhile, the effect of calcination temperature on the physicochemical properties of α-Bi2O3/g-C3N4 was studied. All results confirmed that calcination temperature greatly influences structural, morphology, surface states, photoelectrochemical property and photocatalytic (PC) performance of α-Bi2O3/g-C3N4 composite. Furthermore, the α-Bi2O3/g-C3N4 composite was applied as photocatalyst to degrade amido black 10B dye under visible light irradiation. It was found that the composite synthesized at 400 ℃ exhibited the highest PC performance due to the intense visible light absorbance and high separation efficiency of electron and hole pairs. Besides, the possible PC mechanism was proposed that the photo-generated charge carrier migration in α-Bi2O3/g-C3N4 photocatalyst followed a Z-scheme structure. Finally, the stability test also manifest that the α-Bi2O3/g-C3N4 composite photocatalyst has good stability and reusability, which was a promising candidate for wastewater treatment.
Metal organic frameworks (MOFs) has broad application prospect in separation, catalysis, and adsorption. By a facile green method, we successfully fabricated prGO@cHKUST-1 composite membrane with the modification of dopamine and orientated growth of MOFs. Mg/Al-layered double hydroxides (Mg/Al-LDHs) was used as a modulator to obtain cubic HKUST-1 (cHKUST-1) with excellent morphology and special properties. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) etc. characterization illustrated successful synthesis of cHKUST-1 and composite membranes. Cubic HKUST-1 can tune the inter-layer spacing of graphene oxide (GO) leading increase in hydrophilicity and flux of the membrane. Meanwhile, the reduction effect of PDA and intercalation effect of MOFs could change the stacked way of GO layers, forming several fuzzy pores and more active sites on membrane surface. The prGO@cHKUST-1 membrane has an excellent rejection for methylene blue (MB) (99.5%) and Congo red (CR) (71.2%). Moreover, the modified membrane exhibited 10 and 5 times higher permeation flux than that of original GO membrane and prGO membrane, respectively. Thus, using orientated growth of MOFs to synthesize GO based composite membrane will provide useful insights in ultrahigh permeation flux membranes of dye and oil-water emulsion separation.
Largely limited by the high dissociation energy of the O—O bond, the photocatalytic molecular oxygen activation is highly challenged, which restrains the application of photocatalytic oxidation technology for atmospheric pollutants removal. Herein, we design and fabricate the InP QDs/g-C3N4 compounds. The introduction of InP QDs promotes the charge transfer within the interface resulting in the effective separation of photo-generated carriers. Furthermore, InP QDs greatly facilitates the activation of molecular oxygen and promote the formation of O2·- under visible-light illumination. These conclusions are identified by experimental and calculation results. Hence, NO can be combined with the O2·- to form O—O—N—O intermediate to direct conversion into NO3-. As a result, the NO removal ratio of g-C3N4 has a onefold increase after InP QDs loaded and the generation of NO2 is effectively inhibited. This work may provide a strategy to design highly efficient materials for molecular oxygen activation.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
