Nanohybrid of Carbon Quantum Dots/Molybdenum Phosphide Nanoparticle for Efficient Electrochemical Hydrogen Evolution in Alkaline Medium

The exploration of highly efficient non-noble metal electrocatalysts for hydrogen evolution reaction (HER) under alkaline conditions is highly imperative but still remains a great challenge. In this work, the nanohybrid of carbon quantum dots and molybdenum phosphide nanoparticle (CQDs/MoP) has been firstly demonstrated as an efficient alkaline HER electrocatalyst. The CQDs/MoP nanohybrid is readily prepared through a charge-directed self-assembly of CQDs with phosphomolybdic acid (H₃PMo₁₂O₄₀) at the molecular level, followed by facile phosphatizing at 700 °C. The introduction of CQDs greatly helps to alleviate the agglomeration and surface oxidation of MoP nanoparticles and ensures each MoP nanoparticle to be electronically addressed, thus significantly enhancing the intrinsic catalytic activity of MoP. The optimized CQDs/MoP exhibits high-efficiency synergistic catalysis toward HER in 1 M KOH electrolyte with a low onset potential of −0.08 V and a small Tafel slope of 56 mV dec^–1 as well as high durability with negligible current loss for at least 24 h

Tunable, Strain-Controlled Nanoporous MoS₂ Filter for Water Desalination

The deteriorating state of global fresh water resources represents one of the most serious challenges that scientists and policymakers currently face. Desalination technologies, which are designed to extract potable water from the planet’s bountiful stores of seawater, could serve to alleviate much of the stress that presently plagues fresh water supplies. In recent decades, desalination methods have improved via water-filtering architectures based on nanoporous graphene filters and artificial membranes integrated with biological water channels. Here, we report the auspicious performance (in simulations) of an alternative nanoporous desalination filter constructed from a MoS₂ nanosheet. In striking contrast to graphene-based filters, we find that the “open” and “closed” states of the MoS₂ filter can be regulated by the introduction of mechanical strain, yielding a highly tunable nanopore interface. By applying lateral strain to the MoS₂ filter in our simulations, we see that the transition point between “open” and “closed” states occurs under tension that induces about 6% cross-sectional expansion in the membrane (6% strain); the open state of the MoS₂ filter demonstrates high water transparency and a strong salt filtering capability even under 12% strain. Our results thus demonstrate the promise of a controllable nanoporous MoS₂ desalination filter, wherein the morphology and size of the central nanopore can be precisely regulated by tensile strain. These findings support the design and proliferation of tunable nanodevices for filtration and other applications

Hyper-Cross-linked Porous MoS₂–Cyclodextrin-Polymer Frameworks: Durable Removal of Aromatic Phenolic Micropollutant from Water

A reasonable and efficient strategy for the construction of hyper-cross-linked porous MoS₂–CD-polymer frameworks (MoS₂CDPFs) was demonstrated. Here, MoS₂ nanosheets (NSs) can be decorated with amino functionalized β-cyclodextrin, producing a nanoscale structural motif (MoS₂@CD) for the synthesis of MoS₂CDPFs. We demonstrated that CD polymer (CDP) as linker can be uniformly incorporated into the frameworks. Except for the pores created between MoS₂ NSs, polymer doping generates extra interspace between MoS₂ NSs and CD monomer. Interestingly, the resultant MoS₂CDPFs can rapidly sequester aromatic phenolic micropollutant bisphenol A (0.1 mM) from water with 93.2% adsorption capacity, which is higher than that of MoS₂, MoS₂@CD, and CDP. The intercalation between MoS₂ sheets with CDP imparts the frameworks durability in adsorption/desorption of aromatic phenolic micropollutants. Remarkably, the removal efficiency reduced only 3% after 10 regeneration–reuse cycles. These findings demonstrated that the porous MoS₂–CD-polymer-based frameworks are promising adsorbents for rapid, flow-through water remediation

Chemical Adsorption Enhanced CO₂ Capture and Photoreduction over a Copper Porphyrin Based Metal Organic Framework

Effective CO₂ capture and activation is a prerequisite step for highly efficient CO₂ reduction. In this study, we reported a case of Cu²⁺ in a porphyrin based MOF promoted enhanced photocatalytic CO₂ conversion to methanol. Compared with the sample without Cu²⁺, the methanol evolution rate was improved as high as 7 times. In situ FT-IR results suggested that CO₂ chemical adsorption and activation over Cu²⁺ played an important role in improving the conversion efficiency

Visible-Light-Induced Effects of Au Nanoparticle on Laccase Catalytic Activity

A deep understanding of the interaction between the nanoparticle and enzyme is important for biocatalyst design. Here, we report the <i>in situ</i> synthesis of laccase–Au NP (laccase–Au) hybrids and its catalytic activity modulation by visible light. In the present hybrid system, the activity of laccase was significantly improved (increased by 91.2% vs free laccase) by Au NPs. With a short time visible light illumination (λ > 420 nm, within 3 min), the activity of laccase–Au hybrids decreased by 8.1% (vs laccase–Au hybrid without light), which can be restored to its initial one when the illumination is removed. However, after a long time illumination (λ > 420 nm, over 10 min), the catalytic activity of laccase–Au hybrids consecutively decreases and is not reversible even after removing the illumination. Our experiments also suggested that the local surface plasma resonance effect of Au NPs causes the structure change of laccase and local high temperature near the Au NPs. Those changes eventually affect the transportation of electrons in laccase, which further results in the declined activity of laccase

Bacteria-Activated Theranostic Nanoprobes against Methicillin-Resistant <i>Staphylococcus aureus</i> Infection

Despite numerous advanced imaging and sterilization techniques available nowadays, the sensitive <i>in vivo</i> diagnosis and complete elimination of drug-resistant bacterial infections remain big challenges. Here we report a strategy to design activatable theranostic nanoprobes against methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections. This probe is based on silica nanoparticles coated with vancomycin-modified polyelectrolyte-cypate complexes (SiO₂-Cy-Van), which is activated by an interesting phenomenon of bacteria-responsive dissociation of the polyelectrolyte from silica nanoparticles. Due to the aggregation of hydrophobic cypate fluorophores on silica nanoparticles to induce ground-state quenching, the SiO₂-Cy-Van nanoprobes are nonfluorescent in aqueous environments. We demonstrate that MRSA can effectively pull out the vancomycin-modified polyelectrolyte-cypate complexes from silica nanoparticles and draw them onto their own surface, changing the state of cypate from off (aggregation) to on (disaggregation) and leading to <i>in vitro</i> MRSA-activated near-infrared fluorescence (NIRF) and photothermal elimination involving bacterial cell wall and membrane disruption. <i>In vivo</i> experiments show that this <i>de novo</i>-designed nanoprobe can selectively enable rapid (4 h postinjection) NIRF imaging with high sensitivity (10⁵ colony-forming units) and efficient photothermal therapy (PTT) of MRSA infections in mice. Remarkably, the SiO₂-Cy-Van nano­probes can also afford a long-term tracking (16 days) of the development of MRSA infections, allowing real-time estimation of bacterial load in infected tissues and further providing a possible way to monitor the efficacy of antimicrobial treatment. The strategy of bacteria-activated polyelectrolyte dissociation from nanoparticles proposed in this work could also be used as a general method for the design and fabrication of bacteria-responsive functional nanomaterials that offer possibilities to combat drug-resistant bacterial infections

Modifying Role of GSTP1 Polymorphism on the Association between Tea Fluoride Exposure and the Brick-Tea Type Fluorosis

<div><p>Background</p><p>Brick tea type fluorosis is a public health concern in the north-west area of China. The association between SNPs of genes influencing bone mass and fluorosis has attracted attention, but the association of SNPs with the risk of brick-tea type of fluorosis has not been reported.</p><p>Objective</p><p>To investigate the modifying roles of GSTP1 rs1695 polymorphisms on this association.</p><p>Methods</p><p>A cross-sectional study was conducted. Brick-tea water was tested by the standard of GB1996-2005 (China). Urinary fluoride was tested by the standard of WS/T 89-2006 (China). Skeletal fluorosis was diagnosed by X-ray, the part we scheduled was forearm, shank, and pelvic, then diagnosed the skeletal fluorosis by the standard of WS/192-2008 (China). Gene polymorphism was tested by Sequenom MassARRAY system.</p><p>Result</p><p>The prevalence rate in different ethnical participants was different: Tibetan individuals had the highest prevalence rate of skeletal fluorosis. There were significant differences in genotype frequencies of GSTP1 Rs1695 among different ethnical participants (p<0.001): Tibetan, Mongolian and Han subjects with homozygous wild type (GSTP1-AA) genotype were numerically higher than Kazakh and Russian subjects (<i>p</i><0.001). Compared to Tibetan participants who carried homozygous A allele of GSTP1 Rs1695, Tibetan participants who carried G allele had a significantly decreased risk of skeletal fluorosis (OR = 0.558 [95% CI, 0.326-0.955]). For Kazakh participants, a decreased risk of skeletal fluorosis among carriers of the G allele was limited to non high-loaded fluoride status (OR = 0. 166 [95% CI, 0.035–0.780] vs. OR = 1.478 [95% CI, 0.866–2.552] in participants with high-loaded fluoride status). Neither SNP-IF nor SNP-age for GSTP1 Rs1695 was observed.</p><p>Conclusion</p><p>The prevalence rate of the brick tea type fluorosis might have ethnic difference. For Tibetan individuals, who had the highest prevalence rate, G allele of GSTP1 Rs1695 might be a protective factor for brick tea type skeletal fluorosis.</p></div

Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects overall and stratified by ethnicity.

<p>* Adjusted for age, sex, ethnicity, and fluoride exposure.</p><p>Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects overall and stratified by ethnicity.</p

Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects, stratified by IF levels.

<p>Adjusted for age, sex, ethnicity, and fluoride exposure. p value testing heterogeneity.</p><p>Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects, stratified by IF levels.</p

Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects, stratified by age.

<p>Adjusted for sex, ethnicity, IF and fluoride exposure. p value testing heterogeneity.</p><p>Risk of skeletal fluorosis associated with GSTP1 Rs1695 in subjects, stratified by age.</p