Latest ArticlesA gold nanoparticle (AuNP) aggregation-induced colorimetric aptasensing method for quantitative detection of sulfadimethoxine (SDM) with a smartphone was developed. AuNPs were complexed with aptamers which protected AuNPs from aggregating in high-concentration salt solutions. In the presence of SDM, SDM bound with the aptamer on the surface of AuNPs with higher affinity, which competitively desorbed the aptamer from the AuNP surface and resulted in AuNPs aggregation, accompanied with a color change from red to purple-blue. The R, G and B values of images taken by a smartphone camera were analyzed with an app on the smartphone, and were utilized for quantitative analysis of SDM. Under the optimized conditions, the colorimetric aptasensing method using a smartphone showed high sensitivity for SDM, with the limit of detection of 0.023 ppm, lower than the allowed maximum SDM residue limit. This study provides a simple, fast, and easy to read method for on-site quantitative biochemical and cellular analysis.
Pure organic room-temperature phosphorescence (RTP) materials have attracted wide attention owing to their excellent luminescent properties and great potential in various applications. In this work, iminostilbene and its analogues are applied to realize RTP emission by copolymerizing with acrylamide. It can be concluded that the growth of alkane chain in monomers can enhance the lifetime and photoluminescence quantum yield of RTP emission, and polymers with the larger conjugated structure of the monomer show a longer RTP emission wavelength. This work provides a series of new pure organic RTP materials and might provide new thoughts for designing more advanced and superior RTP materials.
Naphthyridine-fused bisimidazolium salts were designed and synthesized for the first time. The study of the Cu(Ⅱ) and Pd(Ⅱ) complexes demonstrated that the deprotonated dicarbene ligands are rigid chelating C, C-ligands with strong electron-donating ability in analogy with the classic phenanthroline N, N-ligands.
The photocatalytic reduction of CO2 to energy-rich chemicals is highly appealing for alleviation of energy crisis and environment pollution. The introduction of different active sites is a key factor to determine the reaction activity and selectivity. Here, we demonstrate the metal ion-dependent performance for photocatalytic CO2 reduction by anchoring transition metal ions (Co2+ and Ni2+) in an amine-functionalized boron imidazolate framework (BIF-43). As a result, Ni@BIF-43 realized a high selectivity of 90.2% for the CO2-to-CO, while Co@BIF-43 achieved more efficient conversion with a high CO production rate of 2036.0 µmol g−1 h−1. Significantly, precise control of isolated metal site on a well-defined structure through coordination-assisted strategies enables us to better understand the specific effects of different metal-ion species on photoreduction of CO2 as well as the catalytic mechanism.
The first example of stereoconvergent 1, 3-dipolar cycloaddition of nitrile oxides and nitrile imines with E/Z isomeric mixture of electron-deficient olefins is reported, delivering isoxazolines and pyrazolines bearing two vicinal stereogenic tertiary and trifluoromethylated quaternary carbon centers with perfect regio- and diastereoselectivities. The possibility of concerted cycloaddition/epimerization sequence under basic condition to form the thermodynamically stable diastereomers is excluded through some control experiments and DFT calculations, and a stepwise mechanism is proposed.
Enzyme assisted DNA probes are powerful tools in molecular diagnostics for their simplicity, rapidity, and low detection limit. However, cost of probes, difficulty in optimization and disturbance of secondary structure hindered the wider application of enzyme assisted DNA probes. To solve the problems, we designed a new system named shared-probe system. By introducing two unlabeled single stranded DNA named Sh1 and Sh2 as the bridge between probe and the substrate, the same sequence of dually labeled probe with stable performance was shared for different mutations, thus sparing the expense and time cost on designing, synthesizing and optimizing corresponding probes. Besides, the hybridization between Sh1 and the substrate could overcome secondary structures, which guaranteed the detection of different substrates. The performance and generality of the design were tested by low abundance detection in synthetic single DNA samples and the limit of detection was 0.05% for PTENR130Q, EGFR-L858R and 0.02% for BRCA1-NM007294.3. In genomic DNA samples, the limit of detection of 0.1% can be achieved for EGFR-L858R, demonstrating the potential of clinical application in our design.
Oxygen evolution reaction (OER) is pivotal to drive green hydrogen generation from water electrolysis, but yet is strictly overshadowed by the sluggish reaction kinetics. Earth-abundant and cut-price transition-metal compounds, particularly CoFe layered-double-hydroxides (LDHs), show the distinct superiorities in contrast to noble metals and their derivatives. In this review, we firstly underline their fundamental issues in electrocatalytic water oxidation, including CoFe LDHs crystal structure, the surface of (hydr)oxides confined to OER and the controversial roles of Fe species, aiming at understanding the structure-related activity and catalytic mechanism. Advanced approaches for optimizing OER activity of CoFe LDHs are then comprehensively overviewed, which will shed light on the different working mechanisms and provide a concise analysis of their unique advantages. Finally, a perspective on the future development of CoFe LDHs electrocatalysts is offered. We hope this review can give a concise and explicit guidance for the development of transition-metal-based electrocatalysts in the energy field.
Selective hydrogenation of substituted nitroarenes is an important reaction to obtain amines. Supported metal catalysts are wildly used in this reaction because the surface structure of supports can tune the properties of the supported metal nanoparticles (NPs) and promote the selectivity to amines. Herein, Pt NPs were immobilized on FeOOH, Fe3O4 and α-Fe2O3 nanorods to synthesize a series of iron compounds supported Pt catalysts by liquid phase reduction method. Chemoselective hydrogenation of 3-nitrostyrene to 3-aminostyrene was used as probe reaction to evaluate the performance of the catalysts. The results show that Pt/FeOOH exhibits the highest selectivity and activity. FeOOH support with pores and -OH groups can tune the electronic structure of Pt NPs. The positive charge of Pt NPs supported on FeOOH is key factor for improving the catalytic performance.
MeOTf-catalyzed formal [4 + 2] annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized, which undergoes sequential electrophilic cyclization/ring expansion. A range of substrates were tolerated in the formation of naphthalene derivatives with high regioselectivity in satisfactory yields. The reaction could also be carried out on gram scale.
Metabolites can directly reflect and modulate cell responses and phenotypical changes by influencing energy balances, intercellular signals, and many other cellular functions throughout the lifespan of cells. Taking into account the heterogeneity of cells, single-cell metabolite analysis offers an insight into the functional process within one cell. Microfluidics as a powerful tool has attracted significant interest in the single-cell metabolite analysis field. The microfluidic platform is possible to observe, classify, and stimulate individual cells. It can also transport single-cell to subsequent analysis steps in a fast and controllable way to determine and analyze the composition and content of metabolites. The reviews of topics in microfluidics for single-cell metabolite analysis have been published in the past few years. However, most of them focused on metabolite analysis with mass spectrometry. Here, we covered the advances of microfluidic devices for single-cell metabolite analysis, with a focus on single-cell isolation and manipulation. What is more, we summarized the detection methods and applications of single-cell metabolites.