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A multi-ratiometric fluorescence sensor was designed for the sensing of the anthrax biomarker based on a bimetallic lanthanide metal–organic framework.

Nb2O5 can adjust the electronic structure of SNiC2O4 and improve the catalytic activity. Replacing the OER with the HzOR for hydrogen production can save 80% of energy consumption.

The hybrid of l-cysteine and agarose can reduce HAuCl

Thiophenols (ArSHs) are widely used as popular flavoring ingredients for making daily dishes. Dissecting the ArSHs contents in common foodstuffs is meaningful in the field of food safety science. Herein, a novel small-molecule sensor 2-(1H-benzo[d]imidazol-2-yl)-3-(2-(2,4-dinitrophenoxy)-4-morpholinophenyl)acrylonitrile (NOSA) has been tailored. The NOSA is able to respond to ArSHs, spontaneously yielding highly green-emissive fluorescent iminocoumarin (I

Bisulfite (HSO

The development of a sensing platform with high sensitivity and specificity, especially programmability and universal applicability, for the detection of clinically relevant molecules is highly valuable for disease monitoring and confirmation but remains a challenge. Here, for the first time, we introduce the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system into an immobilization-free electrochemical biosensing platform for sensitively and specifically detecting the disease-related nucleic acids and small molecules. In this strategy, a modular rolling circle amplification (RCA) is designed to transform and amplify the target recognition event into the universal trigger DNA strand that is used as the trigger to activate the deoxyribonuclease activity of CRISPR/Cas12a for further signal amplification. The cleavage of the target-activated blocker probe allows the methylene blue-labeled reporter probes to be captured by the reduced graphene oxide-modified electrode, leading to an obviously increased electrochemical signal. We only need to simply tune the sequence for target recognition in RCA components, and this strategy can be flexibly applied to the highly sensitive and specific detection of microRNAs, Parvovirus B19 DNA, and adenosine-5'-triphosphate and the calculated limit of detection is 0.83 aM, 0.52 aM, and 0.46 pM, respectively. In addition, we construct DNA logic circuits (YES, NOT, OR, AND) of DNA inputs to experimentally demonstrate the modularity and programmability of the stimuli-responsive RCA-CRISPR/Cas12a system. This work broadens the application of the CRISPR/Cas12a system to the immobilization-free electrochemical biosensing platform and provides a new thinking for developing a robust tool for clinical diagnosis.

There still exists a resplendent prospect of developing a robust and stable non-noble metal catalyst for overall water splitting. Herein, we designed highly efficient amorphous FeMn-based electroca...

Herein, a novel hemicyanine derivative (E)-3-(1,1-dimethyl-2-(4-(methylthio)styryl)-1H-benzo[e]indol-3-ium-3-yl)propane-1-sulfonate (BIS) has been reasonably designed. Compound BIS is long-wavelength emissive and water-soluble with a large Stokes shift. Intriguingly, probe BIS provides a dual-mode fluorescence response pattern for the sensing of bisulfite (HSO

Semiconducting MoS2 layers offer the electrons, reducing conjugated Au(I) to Au atoms, and sebsequently serve as desirable substrates for supporting the interfacial growths of gold nanostructures. Au-covering MoS2 heterostructures perform morphology-varied optical characteristics, and the surface engineering of MoS2 involved by Hg2+ ions results in the differential growths of nanostructures and morphological diversities. Naked-eye colorimetric responses to mercury ions, with a low limit of detection of 1.27 nM, are achieved based on the in situ grown heterostructures.

The one-to-one coupling nanostructures of individual Au plasmonics and semiconducting MoS2 layers are constructed with the modulation of proteins. The formation of hybrids is attributed to the confinement effect of proteins that are attached to the surfaces of layered MoS2 seeds. From the hybrid nanostructures, enhanced photothermal effects are achieved due to the improvement of Au plasmonic-endowed antenna effects. Significantly, hot electrons triggered from the photonic radiation can rapidly transfer from Au nanoparticles to the conduction band of MoS2 layers and thus the photothermal behaviors are subsequently investigated. Additionally, the hot electron inspired photothermal behaviors are accompanied by the electron transition from the conduction band to the valence band of MoS2 hosts. Significantly, the mechanism of improved photothermal efficiency is ascribed to the synergistic effects. In order to identify the value of photothermal antenna effects, the heat radiation results in the escape of proteins from the interface and a clean surface of MoS2 is obtained. The photonic-responsive interfacial modification of layered MoS2 is promoted. Furthermore, the single-stranded DNA exhibits strong interaction forces with the clean surfaces of MoS2, which can be utilized for the fabrication of fluorescence-sensing assays for DNA and small biomolecules.

The use of a Schlenk line (SL) promotes a strategy involving N-butyllithium for the chemical exfoliation of layered crystals, with the remarkable merits of being low risk and allowing “one-pot” operation. Significantly, metallic-phase and defect-abundant nanosheets are synthesized from SL-exfoliated molybdenum disulphide (SL-MoS2), exhibiting the desired morphological features with a high percentage of monolayers and uniform planar size. Additionally, SL-MoS2 has the excellent structural features of a metallic phase and abundant defects, thereby supporting high activity during the electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the unique structural and morphological characteristics of SL-MoS2 are proved to cause the rapid dissociation of the SL-MoS2 nanosheets in H2O2-rich environments, and the electrocatalytic performance accordingly declines. The HER current density, which is dependent on the number of active sites of SL-MoS2, specifically reflects the reactive-oxygen-species-based degradation of the SL-MoS2 nanoprobes; this can contribute to the electrochemical monitoring of enzyme-associated biological targets and processes using developed chips based on SL-MoS2-modified carbon fibers.

The requirement of hydrogen adsorption Gibbs free energy (ΔGH*) approximating to 0 eV limits the hydrogen evolution reaction (HER) activity of most electrocatalysts in alkaline media. The construction of interface and defects engineering is an effective strategy to obtain the optimal ΔGH*. Ni3N exhibits poor HER activity due to its undesirable ΔGH*. By cooperating with Nb2O5, the d-band center of Ni3N was reduced, improving its catalytic performance. The optimized Nb2O5–Ni3N displays an overpotential of 80 mV at 10 mA cm−2 and superior activity than the benchmark Pt/C catalyst when the current density is greater than 125 mA cm−2. Experimental and density functional theory results demonstrate that the improved catalytic activity is because the electronic interaction between Ni and Nb changes the coordination numbers of these two atoms, resulting in oxygen vacancies at the interface. Under the synergistic effect of Nb2O5 and Ni3N, the catalyst exhibits optimal ΔGH* and water adsorption energy.

Electrochemical water splitting is widely studied in the hope of solving environmental deterioration and energy shortage. The design of inexpensive metal catalysts exhibiting desired catalytic performance and durable stability for efficient oxygen evolution is the pursuit of sustainable and clean energy fields. Herein, a three-dimensional (3D) flower-like NiSe2 primary structure, modified with highly dispersed CuSe2 nanoclusters as the secondary structure, is obtained by regulating the growth trend of the nanosheets. Benefiting from the metallicity of selenides and the formation of a heterogeneous interface, NiSe2@CuSe2/NF shows comparable performance toward the oxygen evolution reaction (OER) in an alkaline environment. Upon regulating the synthesis conditions, the catalyst exhibits its optimal performance with ultralow overpotential for the OER when the Ni/Cu molar ratio is 1 : 0.2 and the hydrothermal temperature and hydrothermal time are 200 °C and 6 h, respectively. It provides a current density of 10 mA cm−2 when a potential of 201 mV is applied without iR compensation. In this work, the hierarchical heterostructures of NiSe2 and CuSe2 are synthesized, which exhibit high electrocatalytic activity towards the oxygen evolution reaction and provides a new possibility for the extensive application of copper-based compounds in advanced energy fields.

A new type of dye with advantages of high selectivity and sensitivity is formed by using the strategy of hybridization between the luminescent unit and recognition unit. Based on this strategy, we exploit a novel dye bonding the benzopyrylium salt as a luminescent unit and phenylboronate group as a response site, which is served as a fluorescent probe 1 for specific recognition of hydrogen peroxide in biological application. Probe 1 employs a unique recognition switch, phenylboronate unit, to"turn-on"a highly specific and rapid fluorescence response toward hydrogen peroxide combined with the 1,6-rearrangement elimination reaction strategy. Meanwhile, probe 1 has the ability to glucose assay by taking advantage of glucose oxidase/glucose enzymatic reaction. What's more, the probe 1 is capable of tracking endogenous hydrogen peroxide in living cells and intracellular imaging. Therefore, the newly developed bioprobe 1 is expected to be used to monitor hydrogen peroxide and glucose levels in complex organisms.

The development of highly efficient oxygen evolution reaction (OER) and urea oxidation reaction (UOR) electrocatalysts with abundant resources is necessary for green hydrogen production. Ni-based compounds have received attention as the most promising earth-abundant electrocatalysts for OER and UOR, whereas some compounds in this main group, e.g., nickel selenides and tellurides, have received little attention. Herein, we demonstrate the interfacial engineered Ni

Development of selective and sensitive methods for on-site assay of tetracycline (TC) is of great significance for public health and food safety. Herein, a valid ratiometric fluorescence strategy using g-C3N4 nanosheets coupled with Eu3+ is designed for the assay of TC. In this strategy, both Eu3+ and g-C3N4 nanosheets serve as the recognition units of TC. The blue fluorescence of g-C3N4 nanosheets can be quenched by TC via the inner filter effect (IFE); meanwhile, the red fluorescence of Eu3+ can be enhanced by TC through the antenna effect (AE). The synergistic effect of AE and IFE caused by TC makes the developed ratiometric fluorescent sensor display a wide linear range for TC from 0.25 to 80 μM with a detection limit of 6.5 nM and a significant fluorescence color evolution from blue to red. Given its simplicity, free-label, excellent selectivity, high sensitivity, and recognizable color change, point-of-care testing systems, including smartphones and test paper-based assays, are developed for the visual sensing of TC. The integration of smartphones and test paper on a ratiometric fluorescent sensor greatly reduces the detection cost and time, providing a promising method for the qualitative discernment and semi-quantitative assay of TC on-site. Moreover, the potential application of the approach is also verified by detecting TC in milk.

Mimic enzymes greatly improve the inherent insufficiencies of natural enzymes. Therefore, mimic enzyme sensors attract increasing research interest. Metal-organic framework (MOF) is emerging in the field of mimic enzyme catalysis due to its remarkable structural properties. In this paper, a colorimetric method is designed for rapid and sensitive detection of glucose and cysteine levels. The MOF Eu-pydc (pydc—2,5-pyridinedicarboxylic acid) is synthesized by a new strategy which is regulated by ligands at room temperature and found to have peroxidase activity. Then, the MOF is used as a mimic enzyme to catalyze chromogenic substrate (3,3′,5,5′-tetramethylbenzidine, TMB) for colorimetric sensing of glucose. The developed method can accurately detect glucose in the range of 10 μM–1 mM (R2 = 0.9958) with a relatively low detection limit about 6.9 μM. Moreover, a cysteine sensor with a detection limit of 0.28 μM is also established based on the disappearance of the color of oxTMB. Additionally, the proposed glucose sensor exhibits excellent selectivity and is successfully applied to blood glucose detection. At the same time, the detection of cysteine is also highly sensitive. In short, the dual sensor is fast, low cost, and convenient, and has great application potential in the diagnosis of disease.

We reported a tin film CMK-3 modified carbon paste electrode (Sn–CMK-3/CPE), a brand new electrode combining the ordered mesoporous carbons (OMCs) and tin film to detect trace cadmium. As one of the OMCs, CMK-3 has the distinct advantage of conducting electrons quickly and good adsorptivity because the pores in it are regularly ordered and controllable with the pore diameters of about 3.8–4.0 nm. Compared to the carbon paste electrode modified by CMK-3 and carbon paste electrode modified by the tin film, the Sn–CMK-3/CPE has higher sensitivity and stability in the process of detecting Cd(II). Under the optimum conditions (mass of CMK-3—4.0 mg; pH 4.70, Sn(II) concentration—6.5 mg/L, deposition potential—1.2 V, deposition time – 300 s), the Sn–CMK-3/CPE indicated a wide linear concentration range of 6–100 μg/L with the detection limit of 0.8 μg/L for Cd(II). This novel sensor was applied to the detection of Cd(II) in river samples with good recoveries.

While it is recognized that instrumentation techniques can provide precise and sensitive solutions to heavy metal ion monitoring, it remains challenging to transform laboratory testing into a convenient, on-site, and quantitative sensing platform for point-of-care testing (POCT) in a resource-constrained setting. To address these limitations, an affordable and user-friendly colorimetric POCT sensing system is proposed here for selectively monitoring four metal ions (Fe

Exploring high active, durable, and earth-abundant electrocatalysts for sustainable hydrogen production is a necessary prerequisite of the future hydrogen economy. Herein, anion-regulation of 3D fl...