Assembling carbon nitride quantum dots into hollow fusiformis and loading CoP for photocatalytic hydrogen evolution.

The self-assembled carbon nitride quantum dots (CNQDs) has been largely advanced owing to the structure-relative photocatalytic activities, especially its electronic structure, which can be regulated by defects, functional groups, and doping. However, there are still issues such as wide band gaps for the assembles and severe recombination of photoinduced charges. Herein, we demonstrate the self-assembly of CNQDs into fusiform hollow superstructures (CNFHs), induced by hydrogen bonding between the terminal functional groups (-OH, -COOH, and -NH2). During the top-down assembly process, the hydrogen bonding dominates and initiates lateral cross-linking between adjacent CNQDs, which further twist into fusiform hollow structures. Benefitted greatly from the ultrathin and hollow nature of the superstructure that provides more exposed active sites, coupled with the introduction of phosphorus doping atoms into the framework induced narrowed band gap, CNFHs exhibits an 18-fold higher activity than the bulk counterpart toward photocatalytic hydrogen evolution after loading the CoP co-catalyst. This work presents a new platform to design and manipulate carbon nitride superstructures.

Tailoring coordination environments of single-atom electrocatalysts for hydrogen evolution by topological heteroatom transfer.

The rational design of carbon-supported transition-metal single-atom catalysts requires the precise arrangement of heteroatoms within the single-atom catalysts. However, achieving this design is challenging due to the collapse of the structure during the pyrolysis. Here, we introduce a topological heteroatom-transfer strategy to prevent the collapse and accurately control the P coordination in carbon-supported single-atom catalysts. As an illustration, we have prepared self-assembled helical fibers with encapsulated cavities. Within these cavities, adjustable functional groups can chelate metal ions (Nx···Mn+···Oy), facilitating the preservation of the structure during the pyrolysis based phosphidation. This process allows for the transfer of heteroatoms from the assembly into single-atom catalysts, resulting in the precise coordination tailoring. Notably, the Co-P2N2-C catalyst exhibits electrocatalytic performance as a non-noble metal single-atom catalyst for alkaline hydrogen evolution, attaining a current density of 100 mA cm-2 with an overpotential of only 131 mV.

Oxygen Vacancy-Dependent Photocatalytic Selective Synthesis of an Unsaturated Amide on Spinel CuFe2O4.

Oxygen vacancies can change the physical and chemical properties of oxide semiconductors, which is applied to the field of ph otocatalysis, including water splitting, carbon dioxide reduction, and organic synthesis. However, the mechanism of oxygen vacancies in photocatalytic organic synthesis is still unclear. Herein, oxygen vacancies constructed on spinel CuFe2O4 nanoparticles were found to trigger the photocatalytic synthesis of an unsaturated amide with high conversion and selectivity. Such superior performance was attributed to the fact that the enriched surface oxygen vacancies could increase the charge separation efficiency and optimize the reaction path, which has been demonstrated both experimentally and theoretically.

Correction: Wet chemical epitaxial growth of a cactus-like CuFeO2/ZnO heterojunction for improved photocatalysis.

Correction for 'Wet chemical epitaxial growth of a cactus-like CuFeO2/ZnO heterojunction for improved photocatalysis' by Tengfei Jiang, et al., Dalton Trans., 2020, DOI: 10.1039/d0dt01813a.

Wet chemical epitaxial growth of a cactus-like CuFeO2/ZnO heterojunction for improved photocatalysis.

Herein, a wet chemical epitaxial growth method was employed to fabricate a cactus-like CuFeO2/ZnO heterojunction for the photocatalytic reduction of benzaldehyde to benzyl alcohol. The 1D ZnO nanorods in the heterojunction make contact with the 2D CuFeO2 nanoflakes at the atomic level, therefore providing a fast charge transfer channel along the direction parallel to the CuFeO2c-axis, leading to efficient charge separation and improved photocatalytic performance.

Synergistically boosting the oxygen evolution reaction of an Fe-MOF via Ni doping and fluorination.

An efficient approach to boost the oxygen evolution activity of Fe-MOF nanorods was demonstrated via a synergistic strategy of Ni doping and fluorination.

Semiconducting Polymer Nanobiocatalysts for Photoactivation of Intracellular Redox Reactions.

An organic semiconducting polymer nanobiocatalyst (SPNB) composed of a semiconducting polymer core conjugated with microsomal cytochrome P450 (CYP) has been developed for photoactivation of intracellular redox. The core serves as the light-harvesting unit to initiate photoinduced electron transfer (PET) and facilitate the regeneration of dihydronicotinamide adenine dinucleotide phosphate (NADPH), while CYP is the catalytic center for intracellular redox. Under light irradiation, the semiconducting core can efficiently catalyze the generation of NADPH with a turnover frequency (TOF) 75 times higher than the reported nanosystems, ensuring the supply of the cofactor for intracellular redox. SPNB-mediated intracellular redox thus can be efficiently activated by light in living cells to convert the model substrate and also to trigger the bioactivation of anticancer drugs. This study provides an organic nanobiocatalytic system that allows light to remotely control intracellular redox in living systems.

Systematic Bandgap Engineering of Graphene Quantum Dots and Applications for Photocatalytic Water Splitting and CO2 Reduction.

Graphene quantum dots (GQDs), which is the latest addition to the nanocarbon material family, promise a wide spectrum of applications. Herein, we demonstrate two different functionalization strategies to systematically tailor the bandgap structures of GQDs whereby making them snugly suitable for particular applications. Furthermore, the functionalized GQDs with a narrow bandgap and intramolecular Z-scheme structure are employed as the efficient photocatalysts for water splitting and carbon dioxide reduction under visible light. The underlying mechanisms of our observations are studied and discussed.

A Swellable Microneedle Patch to Rapidly Extract Skin Interstitial Fluid for Timely Metabolic Analysis.

Skin interstitial fluid (ISF) is an emerging source of biomarkers for disease diagnosis and prognosis. Microneedle (MN) patch has been identified as an ideal platform to extract ISF from the skin due to its pain-free and easy-to-administrated properties. However, long sampling time is still a serious problem which impedes timely metabolic analysis. In this study, a swellable MN patch that can rapidly extract ISF is developed. The MN patch is made of methacrylated hyaluronic acid (MeHA) and further crosslinked through UV irradiation. Owing to the supreme water affinity of MeHA, this MN patch can extract sufficient ISF in a short time without the assistance of extra devices, which remarkably facilitates timely metabolic analysis. Due to covalent crosslinked network, the MN patch maintains the structure integrity in the swelling hydrated state without leaving residues in skin after usage. More importantly, the extracted ISF metabolites can be efficiently recovered from MN patch by centrifugation for the subsequent offline analysis of metabolites such as glucose and cholesterol. Given the recent trend of easy-to-use point-of-care devices for personal healthcare monitoring, this study opens a new avenue for the development of MN-based microdevices for sampling ISF and minimally invasive metabolic detection.

Cobalt Phosphide Double-Shelled Nanocages: Broadband Light-Harvesting Nanostructures for Efficient Photothermal Therapy and Self-Powered Photoelectrochemical Biosensing.

Ultra-broadband light-absorbing materials are highly desired for effective solar-energy harvesting. Herein, novel cobalt phosphide double-shelled nanocages (CoP-NCs) are synthesized. Uniquely, these CoP-NCs are able to nonselectively absorb light spanning the full solar spectrum, benefiting from its electronic properties and hollow nanostructure. They promise a wide range of applications involving solar energy utilization. As proof-of-concept demonstrations, CoP-NCs are employed here as effective photothermal agents to ablate cancer cells by utilizing their ability of near-infrared heat conversion, and as photoactive material for self-powered photoelectrochemical sensing by taking advantage of their ability of photon-to-electricity conversion.

Anti-CD24 neutralizing antibody exacerbates Concanavalin A-induced acute liver injury in mice via liver M1 macrophages.

Liver largely relies on its innate immunity to initiate quick and effective defense against potentially toxic agents, and innate immune cells are major players in this process. However, excessive inflammation due to out-of-control immune response may eventually cause liver injury. Thus, it is important to fully understand the regulatory mechanisms associated with liver inflammation. Here we showed that anti-CD24 neutralizing antibody exacerbated hepatic inflammation in a Con A-induced acute liver injury murine model. Our results supported that hepatic macrophages were required for anti-CD24 neutralizing antibody-aggravated liver inflammation, as depletion of macrophages significantly alleviated Con A-induced inflammation. M1 macrophages, but not M2 macrophages, were specifically induced by Con A, and more greatly by Con A in combination with anti-CD24 neutralizing antibody. The combined treatment further promoted M1 hepatic macrophages to express TNF-α, which increased hepatocytes apoptosis. Taken together, these data suggest that anti-CD24 neutralizing antibody plays an important role in aggravating inflammation in the process of Con A-induced acute liver injury in mice. The possible mechanism might involve the enhanced secretion of TNF-α by hepatic M1 macrophages. This study also implicates a role for CD24 in negative regulation of Con A-induced liver inflammation.

Monitoring Dynamic Cellular Redox Homeostasis Using Fluorescence-Switchable Graphene Quantum Dots.

Monitoring cellular redox homeostasis is critical to the understanding of many physiological functions ranging from immune reactions to metabolism, as well as to the understanding of pathological development ranging from tumorigenesis to aging. Nevertheless, there is currently a lack of appropriate probes for this ambition, which should be reversibly, sensitively, and promptly responsive to a wide range of physiological oxidants and reductants. In this work, a redox-sensitive fluorescence-switchable probe is designed based on graphene quantum dots (GQDs) functionalized with a chelated redox Fe2+/Fe3+ couple. The underlying mechanism is investigated and discussed. The high sensitivity and fast response are attributable to the fact that the GQD's photoluminescence is highly sensitive to photon-induced electron transfer because of its ultrasmall size and associated prominent quantum confinement effect. Also taking advantages of GQDs' excellent photostability, biocompatibility, and readiness for cell uptake, our reversibly tunable fluorescence probe is employed to monitor in real time the triggered dynamic change of the intracellular redox state. This addition to the limited arsenal of available redox probes shall be useful to the still poorly understood redox biology, as well as for monitoring environment or chemical processes involving redox reactions.

N-doped carbon-coated tungsten oxynitride nanowire arrays for highly efficient electrochemical hydrogen evolution.

It is highly desired but still challenging to develop active nonprecious metal hydrogen evolution reaction (HER) electrocatalysts operating under all pH conditions. Herein, the development of three-dimensional N-doped carbon-coated tungsten oxynitride nanowire arrays on carbon cloth as a highly efficient and durable HER cathode was explored. The material delivers current densities of 10 and 100 mA cm(-2) at overpotentials of 106 and 172 mV, respectively, in acidic medium, and it also performs well in neutral and basic electrolytes.

Rapid, sensitive, and selective fluorescent DNA detection using iron-based metal-organic framework nanorods: Synergies of the metal center and organic linker.

Considerable recent attention has been paid to homogeneous fluorescent DNA detection with the use of nanostructures as a universal "quencher", but it still remains a great challenge to develop such nanosensor with the benefits of low cost, high speed, sensitivity, and selectivity. In this work, we report the use of iron-based metal-organic framework nanorods as a high-efficient sensing platform for fluorescent DNA detection. It only takes about 4 min to complete the whole "mix-and-detect" process with a low detection limit of 10 pM and a strong discrimination of single point mutation. Control experiments reveal the remarkable sensing behavior is a consequence of the synergies of the metal center and organic linker. This work elucidates how composition control of nanostructures can significantly impact their sensing properties, enabling new opportunities for the rational design of functional materials for analytical applications.

Cobalt phosphide nanowires: efficient nanostructures for fluorescence sensing of biomolecules and photocatalytic evolution of dihydrogen from water under visible light.

The detection of specific DNA sequences plays an important role in the identification of disease-causing pathogens and genetic diseases, and photochemical water splitting offers a promising avenue to sustainable, environmentally friendly hydrogen production. Cobalt-phosphorus nanowires (CoP NWs) show a high fluorescence quenching ability and different affinity toward single- versus double-stranded DNA. Based on this result, the utilization of CoP NWs as fluorescent DNA nanosensors with a detection limit of 100 pM and a selectivity down to single-base mismatch was demonstrated. The use of a thrombin-specific DNA aptamer also enabled the selective detection of thrombin. The photoinduced electron transfer from the excited dye that labels the oligonucleotide probe to the CoP semiconductor led to efficient fluorescence quenching, and largely enhanced the photocatalytic evolution of hydrogen from water under visible light.

Acidically oxidized carbon cloth: a novel metal-free oxygen evolution electrode with high catalytic activity.

The efficiency of many energy storage technologies is limited by the sluggish kinetics of the oxygen evolution reaction (OER) and it is thus of great importance to develop highly active OER electrocatalysts made from earth-abundant elements. In this communication, we report a novel metal-free oxygen evolution electrode with high catalytic activity and stability through simple acidic oxidation of commercially available carbon cloth (CC). The resulting acidically oxidized CC exhibits an overpotential of 328 mV and a Tafel slope of 82 mV dec(-1) with 100% Faradaic efficiency. This electrode needs an overpotential of 477 mV to afford a current density of 10 mA cm(-2) and maintains its catalytic activity for at least 24,000 s. It offers us a low-cost flexible electrocatalytic electrode for device integration toward water splitting and rechargeable metal-air battery applications.

FeP nanoparticles film grown on carbon cloth: an ultrahighly active 3D hydrogen evolution cathode in both acidic and neutral solutions.

In this Letter, we demonstrate the direct growth of FeP nanoparticles film on carbon cloth (FeP/CC) through low-temperature phosphidation of its Fe3O4/CC precursor. Remarkably, when used as an integrated 3D hydrogen evolution cathode, this FeP/CC electrode exhibits ultrahigh catalytic activity comparable to commercial Pt/C and good stability in acidic media. This electrode also performs well in neutral solutions. This work offers us the most cost-effective and active 3D cathode toward electrochemical water splitting for large-scale hydrogen fuel production.

Primary paraganglioma located between the thyroid gland and the left common carotid artery: A case report.

Head and neck paraganglioma is a rare and predominantly asymptomatic tumor. In the present study, an extremely rare case of asymptomatic paraganglioma located between the left common carotid artery and the left thyroid is described. The clinical presentation, cytomorphology and the immunohistochemical characteristics for the diagnosis of head and neck paraganglioma are described. To the best of our knowledge, only two cases of paraganglioma located between the left common carotid artery and the left thyroid have previously been reported.

A cost-effective 3D hydrogen evolution cathode with high catalytic activity: FeP nanowire array as the active phase.

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its ß-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm(2) , respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production.

Graphitic carbon nitride nanosheets: one-step, high-yield synthesis and application for Cu2+ detection.

In this article we report on the one-step, rapid, high-yield synthesis of graphitic carbon nitride (g-C3N4) nanosheets for the first time. The nanosheets were obtained by pyrolyzing a melamine-KBH4 mixture under Ar. As a fluorosensor for Cu(2+), the g-C3N4 nanosheets exhibit a detection limit as low as 0.5 nM and high selectivity in buffer solutions, and this sensor was applied to the analysis of lake water samples. The electrogenerated chemiluminescence (ECL) behavior of the g-C3N4 nanosheets using Na2S2O8 as the coreactant was also studied. Results suggest that the ECL intensity of the g-C3N4 nanosheets was linear over concentrations of 0-45 nM, with a detection limit of 1.2 nM for Cu(2+).