Novel cobalt-doped molybdenum oxynitride quantum dot@N-doped carbon nanosheets with abundant oxygen vacancies for long-life rechargeable zinc-air batteries

Journal of Materials Chemistry A

Rechargeable zinc-air batteries (ZABs) have emerged as promising alternatives for conventional Li-ion batteries due to their high energy density and low manufacturing cost. However, Pt/C and RuO2-based conventional rechargeable ZABs are mainly constrained by the sluggish kinetics of oxygen reduction/oxygen evolution reactions (ORR/OER), limiting commercialization possibilities. Herein, a new type of oxygen vacancies enriched cobalt-doped molybdenum oxynitride quantum dot-anchored N-doped carbon nanosheets (VO-CMON@NCNs) was demonstrated as an advanced air-cathode for long-life rechargeable ZABs. Such VO-CMON@NCN catalyst has an exceptional ORR performance with a high half-wave potential of 0.857 V and tremendous OER performance with an ultrasmall overpotential of 240 mV at a current density of 10 mA cm−2, outperforming conventional Pt/C and RuO2catalysts. As proof of concept, rechargeable ZABs with an optimal VO-CMON@NCN-800 air-cathode showed an ultrahigh specific capacity of 721.2 mA h gZn−1at a current density of 5 mA cm−2, a tremendous peak power density of 143.7 mW cm−2, and ultralong cycling life of 500 h. These consequences suggest that the oxygen vacancies enriched VO-CMON@NCN can serve as promising bifunctional catalysts for next-generation metal-air batteries and other energy-related applications. © The Royal Society of Chemistry 2021.

Rationally designed NiS2-MnS/MoS2 hybridized 3D hollow N-Gr microsphere framework-modified celgard separator for highly efficient Li-S batteries

Applied Catalysis B: EnvironmentalA

This work develops a multifunctional separator, as trapper-catalyst-conductor, for Li-S batteries through modifying a Celgard separator by a novel hybrid comprising NiS2-MnS on a MoS2 nanosheets/3D hollow N-doped graphene microsphere framework. Benefiting from the great adsorption ability of MoS2 and NiS2-MnS for polysulfide species, the separator demonstrates high-efficiency polysulfide trapping. The ultrafine NiS2-MnS nanoparticles induce the developed separator to offer abundant catalytic active sites and efficient catalytic behavior for fast polysulfide redox. Furthermore, the super-structured N-doped 3D hollow graphene microsphere substrate can prevent both NiS2-MnS and MoS2 from agglomeration phenomenon during the synthesis/operation process, while providing a highway for electron transportation to catalytic active sites. Importantly, the excellent mesoporous architecture of the coating material facilitates the diffusion of Li ion. Therefore, the Li-S battery constructed by the proposed separator shows a much higher performance and superior cycling stability than that of the cell using pristine Celgard separator. © 2022 Elsevier B.V.

A fast and label-free detection of hydroxymethylated DNA using a nozzle-jet printed AuNPs@Ti3C2 MXene-based electrochemical sensor

Talanta

5-hydroxymethylcytosine (5hmC) is a key epigenetic mark in the mammalian genome that has been proposed as a promising cancer biomarker with diagnostic and prognostic potentials. A new type of two-dimensional (2D) material called MXene includes transition metal carbides and nitrides and possesses unique physico-chemical properties suitable for diverse applications, including electrochemical sensors. Here, we report a new nozzle-jet printed electrochemical sensor using gold nanoparticles (AuNPs)@Ti3C2 MXene nanocomposite for the real-time and label-free detection of 5hmC in the genome. We utilized Ti3C2 MXene as a platform to immobilize AuNPs, which have been shown to exhibit different affinity interactions toward 5-methylcytosine (5 mC) and 5hmC, and thus produce distinct electrochemical responses. To fabricate the electrode, a highly conductive and adhesive silver ink was prepared to generate a silver line onto polyethylene terephthalate (PET) substrate using nozzle-jet printing, followed by deposition of AuNPs@Ti3C2 MXene ink at one end via dropcasting. Analyses of morphology and chemical composition showed that all steps of the sensor fabrication were successful. The fabricated sensor coupled with cyclic voltammetry showed excellent performance in distinguishing 5 mC- or 5hmC-enriched cellular genomic DNAs. As a proof-of-concept investigation, we confirmed that our sensor readily and consistently detected 5hmC diminution in multiple tumors, compared to the paired normal tissues. Thus, our simple and cost-effective sensing strategy using printable AuNPs@Ti3C2 MXene ink holds promise for a wide range of practical applications in epigenetic studies as well as clinical settings. © 2022

Highly stable and Efficient Perovskite Solar Cells Based on FAMA-Perovskite-Cu:NiO Composites with 20.7% Efficiency and 80.5% Fill Factor

Advanced Energy Materials

To solve critical issues related to device stability and performance of perovskite solar cells (PSCs), FA0.026MA0.974PbI3−yCly-Cu:NiO (formamidinium methylammonium (FAMA)-perovskite-Cu:NiO) and Al2O3/Cu:NiO composites are developed and utilized for fabrication of highly stable and efficient PSCs through fully-ambient-air processes. The FAMA-perovskite-Cu:NiO composite crystals prepared without using any antisolvents not only improve the perovskite film quality with large-size crystals and less grain boundaries but also tailor optical and electronic properties and suppress charge recombination with reduction of trap density. A champion device based on the composites as light absorber and Al2O3/Cu:NiO interfacial layer between electron transport layer and active layer yields power conversion efficiency (PCE) of 20.67% with VOC of 1.047 V, JSC of 24.51 mA cm−2, and fill factor of 80.54%. More importantly, such composite-based PSCs without encapsulation show significant enhancement in long-term air-stability, thermal- and photostability with retaining 97% of PCE over 240 d under ambient conditions (25–30 °C, 45–55% humidity). © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Mastocytosis-derived extracellular vesicles deliver miR-23a and miR-30a into pre-osteoblasts and prevent osteoblastogenesis and bone formation

Nature Communications

Osteoporosis and other manifestations of bone disease are frequent in patients with systemic mastocytosis (SM) in association with the presence of mast cell infiltrates in bone marrow, although the mechanisms behind bone disease remain poorly understood. We find that extracellular vesicles (EVs) released by neoplastic mast cells and present in the serum of patients with SM (SM-EVs) block osteoblast differentiation and mineralization in culture, and when injected into mice diminish the expression of osteoblast markers, and trabecular bone volume and microarchitecture. We demonstrate that miRNA-30a and miRNA-23a, increased in SM-EVs and neoplastic mast cell-derived EVs, attenuate osteoblast maturation by suppressing expression of RUNX2 and SMAD1/5, essential drivers of osteogenesis. Thus, SM-EVs carry and deliver miRNAs that epigenetically interfere with bone formation and can contribute to bone mass reduction in SM. These findings also suggest possibilities for novel approaches to the management of bone disease in mast cell proliferative disorders. © 2021, The Author(s).

Silver nanoparticles decorated reduced graphene oxide: Eco-friendly synthesis, characterization, biological activities and embryo toxicity studies

Environmental Research

This study was aimed on the eco-friendly synthesis of silver nanoparticles (AgNPs), reduced graphene oxide (rGO) and AgNPs decorated rGO (rGO/AgNPs) nanocomposite and appraisal of their bioactivities and toxicity. As-prepared nanomaterials were established through high resolution X-ray diffraction (HR-XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV–Vis. spectroscopy and Fourier transform infrared spectroscopy (FT-IR). In this study, leaves extract, graphene oxide (GO) and rGO did not show antibacterial and anticancer activities; no significant embryo toxicity was recorded. On the other hand, AgNPs displayed good antibacterial and anticancer activities; however, higher toxic effects were observed even at the lowest test concentration (0.7 μg/ml). In case of rGO/AgNPs nanocomposite, significant antibacterial activity together with low cytotoxicity was noticed. Interestingly, the embryo toxicity of AgNPs was significantly reduced by rGO, implying the biocompatible nature of as-synthesized nanocomposite. Taken together, these results clearly suggest that rGO/AgNPs nano hybrid composite could be developed as the promising biomaterial for future biomedical applications. © 2022 Elsevier Inc.