Latest ArticlesThe electricity-driven water splitting acts as a promising pathway for renewable energy conversion and storage, yet anodic oxygen evolution reaction (OER) largely hinders its efficiency. Seeking the alternatives to OER exhibits the competitive advance to address this predicament. In this work, we show a more thermodynamically and kinetically favorable reaction, electrochemical oxidative dehydrogenation (EODH) of benzylamine to replace the conventional OER, catalyzed by a cobalt cyclotetraphosphate (Co2P4O12) nanorods catalyst grown on nickel foam. This anodic reaction lowers the electricity input of 317 mV toward the desired current density of 100 mA/cm2, together with a highly selective benzonitrile product of more than 97%. More specifically, when coupling it with cathodic hydrogen evolution reaction (HER), the proposed HER||benzylamine-EODH configuration only requires a cell voltage of 1.47 V@100 mA/cm2, exhibiting an energy-saving up to 17% relative to conventional water splitting, as well as the near unit selectivity toward cathodic H2 and anodic benzonitrile products.
Accurate detection and imaging of adenosine triphosphate (ATP) expression levels in living cells is of great value for understanding cell metabolism, physiological activities, and pathologic mechanisms. Here, we developed a DNA tetrahedron-based split aptamer probe (TD probe) for ratiometric fluorescence imaging of ATP in living cells. The TD probe is constructed by hybridizing two split ATP aptamer probes (Apt-a and Apt-b) to a DNA tetrahedron assembled by four DNA oligonucleotides (T1, T2, T3 and T4). In the presence of ATP, the TD probe will alter its structure from the open to closed state, thus bringing the separated donor and acceptor fluorophores into close proximity for high fluorescence resonance energy transfer (FRET) signals. The TD probe exhibits low cytotoxicity, efficient cell internalization and good biological stability. Moreover, based on the FRET "off" to "on" signal output mode, the TD probe can effectively avoid false-positive signals from complex biological matrices, which is significant for long-term reliable imaging in living cells. In addition, by changing the split aptamers attached to DNA tetrahedron, the proposed strategy may be extended for detecting various intracellular targets. Collectively, this strategy provides a valuable sensing platform for biomarkers analysis in living cells, thus having great potential for early clinical diagnosis and therapeutic evaluation.
Herein, we report a new metal-organic framework with an AIE ligand (H4TCPP = 2,3,5,6-tetra-(4-carboxyphenyl)pyrazine) and Mg2+ ions, that is, [Mg2(H2O)4TCPP]·DMF·5CH3CN (Mg-TCPP, TCPP = tetra-(4-carboxyphenyl)pyrazine) for detection of nitroaromatic explosives. Due to the coordination effect and restricted intramolecular rotation, Mg-TCPP exhibits bright blue light. As a fluorescent sensor, Mg-TCPP exhibits high selectivity and sensitivity for sensing 2,4,6-trinitrophenol (TNP) by quenching behaviors with the Stern-Volmer quenching constant (KSV) of 3.63×105 L/mol and achieves the low limit of detection of 25.6 ppb, which is beyond most of the previously reported fluorescent materials. Notably, the portable Mg-TCPP films are prepared and it can be used for rapid and sensitive TNP detection in a variety of environments including organic solvent and aqueous solution. Moreover, TNP vapor can be detected within 3 min by naked eye and the film could be regenerated under simple solvent cleaning.
As a burgeoning research field, ultrasound-responsive materials have attracted intense interest in healthcare research. However, the basic mechanism of sonochemical effect in the quasi-solid state is far from being well understood than those in the solution. Herein, we showcase mechanochemical transformations of europium(Ⅲ) complexes in a supramolecular hydrogel matrix. With the combination of labile terpyridine-europium complexes (TPY-Eu3+) as mechanochromic moieties and an ultrasound-responsive fluorogen (URF) as a molecular tweezer, the hydrogel produces a notable fluorescence change in response to ultrasound. The mechanochemical transformation was elucidated by molecular dynamics (MD) simulations, and fully probed and evidenced by electrochemical experiments, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy.
Available online two new Ni8Mo8 bimetallic coordination clusters, [Ni4(TC4A)]2[(Mo5ⅤMo3ⅥO24)(PO4)] (+Solvent) (Ni8PMo8, H4TC4A= p-tert-butylthiacalix[4]arene) and [Ni4(TC4A)]2[(Mo5ⅤMo3ⅥO24)(OH)(CO3)] (+Solvent) (Ni8Mo8), were synthesized by solvothermal method and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, FT-IR spectroscopy, and TGA experiments, respectively. The usage of H3PMo12O40 as source for Ni8PMo8 resulted a sandwich like structure built from two Ni4-thiacalix[4]arene units and a Mo8 polyoxometalate with inner spaces of PO43−. Ni8Mo8 with the similar structure to that of Ni8PMo8 is from H2MoO4 starting reagent with OH− and CO32− anions encapsulated in the center. The two clusters can be directly loaded on carbon paper and utilized as working electrodes which showed distinguishable performances for glucose detection and oxidation. This work provides a better understanding of the structure–property relationships in using substituted polyoxometalates for electrochemical applications and is helpful for building calixarene-based or polyoxometalate-based functional materials.
Synthetic conditions and ligands are the key structural defining factors of metal–organic frameworks (MOFs). Therefore, reasonable optimization of these aspects is considered to be an effective means for designing materials with novel structures and target functions. Herein, two novel Co(Ⅱ)-based MOFs, namely [Co(HL)(dibp)]n (HL-8) and {[Co2(L)(OH)(dibp)]·DMA}n (HL-9) (H3L = 2′, 6′-dimethyl-[1,1′-biphenyl]-3,4′,5-tricarboxylic acid; dibp = 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl]), have been hydrothermally synthesized and structurally characterized. HL-8 crystallizes in the orthorhombic system (Pna21) with a grid layer structure, while HL-9 crystallizes in the monoclinic P21/n space group assembled through Co4(OH)2 clusters with organic ligands. Remarkably, benefiting from the finite cage-like structure, HL-9 exhibited enhanced performance in carbon dioxide (CO2) adsorption/catalytic transformation and excellent size selectivity during dye molecular adsorption process.
In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to this problem. Here in this study, a novel organic phototransistor based on a high mobility n-type small molecule as the conducting layer and an isolated bulk heterojunction light-absorbing layer as the floating gate has been demonstrated in this study. With the special designed device structure, the phototransistor shows extremely high sensitivity to broad spectral and weak light irradiation, and the photoresponsivity and photocurrent/dark-current ratio of the device can reach up to 4840 mA/W and 1.8 × 105 respectively. For conclusion, this study suggests a potential way to obtain high-performance phototransistors at room temperature, which will further promote the commercial application of organic phototransistors.
Compared with noble metals, improving the sensitivity of semiconducting surface-enhanced Raman scattering (SERS) substrates is of great significance to their fundamental research and practical application of Raman spectroscopy. Herein, a simple chemical method is developed to synthesize a rhenium trioxide (ReO3) microtubes assembled with highly crystalline nanoparticles. The ReO3 microtubes show a strong and well-defined surface plasmon resonance (SPR) behavior in visible region, which is rare for non-noble metals. As a low-cost SERS substrate, the plasmonic ReO3 microtubes exhibit a Raman enhancement factor of 8.9 × 105 and a lowest detection limit of 1.0 × 10−9 mol/L for phenolic pollutants. Moreover, these ReO3 microtubule SERS substrates show excellent chemical stability and can resist the corrosion of strong acids and bases.
There is no clear consensus regarding how cells respond to hydrostatic pressure. This is largely attributable to the high heterogeneity among cell types and the diverse custom-made devices used in previous studies. The aim of this work was to develop a facile device that could mimic various pressure environments and then delineate the cellular response to pressure stimulus. The device described here achieved both stable and periodic pressurization without oxygen deprivation. The biological utility of the device was assessed using human umbilical vein endothelial cells. We found more stereoscopic nuclear morphology and re-distribution of lamin A/C under high hydrostatic pressure compared to control cells. Mass spectrometry-based proteomics analysis showed significant changes in mitochondria-related pathways. Western blot analysis confirmed that high hydrostatic pressure induced a tendency toward mitochondrial fusion. Increased mitochondrial activity was observed as well. In conclusion, this device can be readily applied in biological research and extend our understanding of cellular mechano-sensation and the associated changes in mitochondrial behaviors.
In-situ monitoring of neurochemicals is of vital importance for the understanding of brain functions. Microelectrode-based photoelectrochemical (PEC) sensing has emerged as a promising tool for in vivo analysis since it inherits the merits of both optical and electrochemical methods. However, the in-situ excitation of photoactive materials on the photoelectrode in living body is still a challenge because of limited tissue penetration depth of light. To circumvent this problem, we herein developed an implantable optical fiber (OF)-based microelectrode for in vivo PEC analysis. The working electrode was constructed by coating Au film as conducting layer and CdS@ZnO as photoactive material on a micron-sized OF, which was free of the limitation of light penetration in biological tissues. Further decoration of an anti-biofouling layer on the surface made the sensor robust in biosamples. It was successfully applied for monitoring Cu2+ level in three different brain regions in the rat model of cerebral ischemia/reperfusion.