An injectable hydrogel scaffold with IL-1ß-activated MSC-derived exosomes for the treatment of endometritis.

Chronic endometritis is a common gynecological disease resulting from various long-term recurrent infections, and is closely related to myositis, miscarriage, and even infertility. There is still no satisfactory treatment method currently in clinical therapy. Mesenchymal stem cell (MSC)-derived exosomes, an important kind of paracrine product, have been used to treat inflammatory diseases due to their promising immunomodulatory function and tissue repair ability similar to MSCs. Considering that the exosome contents and functions are regulated by the MSC status and the MSC status is significantly influenced by its surrounding microenvironment, we propose a hypothesis that exosomes derived from inflammation-simulated MSCs will possess stronger inhibition ability for inflammation. Herein, we used IL-1ß to activate rat bone MSCs for obtaining ß-exo and constructed an injectable polypeptide hydrogel scaffold by loading ß-exo (ß-exo@pep) for an in situ slow release of ß-exo. The results showed that the polypeptide hydrogel can provide a sustained release of exosomes in 14 days. The ß-exo@pep composite hydrogel can more effectively inhibit the production of inflammatory factors such as TNF-α, IL-1ß, and IFN-γ, while it can promote the production of anti-inflammatory factors such as Arg-1, IL-6, and IL-10. The ß-exo@pep composite hydrogel significantly promoted cell migration, invasion, and vessel tube formation in vitro. The experiments in a rat model of endometritis proved that the ß-exo@pep composite scaffold possessed excellent ability towards anti-inflammation and endometrial regeneration. The research studies on the molecular mechanism revealed that the protein expressions of HMGB1 and phosphorylated IKB-α and p65 are down-regulated in the cells treated with ß-exo@pep, indicating the involvement of the NF-κB signaling pathway. This study provides an effective method for the treatment of chronic endometritis, which is promising for clinical use.

Enhanced Activities in Alkaline Hydrogen and Oxygen Evolution Reactions on MoS2 Electrocatalysts by In-Plane Sulfur Defects Coupled with Transition Metal Doping.

2D transition metal disulfides (TMDs) are promising and cost-effective alternatives to noble-metal-based catalysts for hydrogen production. Activation of the inert basal plane of TMDs is crucial to improving the catalytic efficiency. Herein, introduction of in-plane sulfur vacancies (Sv ) and 3d transition metal dopants in concert activates the basal planes of MoS2 (M-Sv -MoS2 ) to achieve high activities in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Acetate introducing mild wet chemical etching removes surface S atoms facilitating subsequent cation exchange between the exposed Mo atoms and targeted metal ions in solution. Density-functional theory calculation demonstrates that the exposed 3d transition metal dopants in MoS2 basal planes serve as multifunctional active centers, which not only reduce ΔGH* but also accelerate water oxidation. As a result, the optimal Ni-Sv -MoS2 and Co-Sv -MoS2 electrocatalysts show excellent stability and alkaline HER and OER characteristics such as low overpotentials of 101 and 190 mV at 10 mA cm-2 , respectively. The results reveal a strategy to activate the inert MoS2 basal planes by defect and doping co-engineering and the technique can be extended to other types of TMDs for high-efficiency electrocatalysis beyond water splitting.

In-Plane Mott-Schottky Effects Enabling Efficient Hydrogen Evolution from Mo5 N6 -MoS2 Heterojunction Nanosheets in Universal-pH Electrolytes.

Cost-effective electrocatalysts for the hydrogen evolution reaction (HER) spanning a wide pH range are highly desirable but still challenging for hydrogen production via electrochemical water splitting. Herein, Mo5 N6 -MoS2 heterojunction nanosheets prepared on hollow carbon nanoribbons (Mo5 N6 -MoS2 /HCNRs) are designed as Mott-Schottky electrocatalysts for efficient pH-universal HER. The in-plane Mo5 N6 -MoS2 Mott-Schottky heterointerface induces electron redistribution and a built-in electric field, which effectively activates the inert MoS2 basal planes to intrinsically increase the electrocatalytic activity, improve electronic conductivity, and boost water dissociation activity. Moreover, the vertical Mo5 N6 -MoS2 nanosheets provide more activated sites for the electrochemical reaction and facilitate mass/electrolyte transport, while the tightly coupled HCNRs substrate and metallic Mo5 N6 provide fast electron transfer paths. Consequently, the Mo5 N6 -MoS2 /HCNRs electrocatalyst delivers excellent pH-universal HER performances exemplified by ultralow overpotentials of 57, 59, and 53 mV at a current density of 10 mA cm-2 in acidic, neutral, and alkaline electrolytes with Tafel slopes of 38.4, 43.5, and 37.9 mV dec-1 , respectively, which are superior to those of the reported MoS2 -based catalysts and outperform Pt in overall water splitting. This work proposes a new strategy to construct an in-plane heterointerface on the nanoscale and provides fresh insights into the HER electrocatalytic mechanism of MoS2 -based heterostructures.

In-Situ Synthesis of Heterostructured Carbon-Coated Co/MnO Nanowire Arrays for High-Performance Anodes in Asymmetric Supercapacitors.

Structural design is often investigated to decrease the electron transfer depletion in/on the pseudocapacitive electrode for excellent capacitance performance. However, a simple way to improve the internal and external electron transfer efficiency is still challenging. In this work, we prepared a novel structure composed of cobalt (Co) nanoparticles (NPs) embedded MnO nanowires (NWs) with an N-doped carbon (NC) coating on carbon cloth (CC) by in situ thermal treatment of polydopamine (PDA) coated MnCo2O4.5 NWs in an inert atmosphere. The PDA coating was carbonized into the NC shell and simultaneously reduced the MnCo2O4.5 to Co NPs and MnO NWs, which greatly improve the surface and internal electron transfer ability on/in MnO boding well supercapacitive properties. The hybrid electrode shows a high specific capacitance of 747 F g-1 at 1 A g-1 and good cycling stability with 93% capacitance retention after 5,000 cycles at 10 A g-1. By coupling with vanadium nitride with an N-doped carbon coating (VN@NC) negative electrode, the asymmetric supercapacitor delivers a high energy density of 48.15 Wh kg-1 for a power density of 0.96 kW kg-1 as well as outstanding cycling performance with 82% retention after 2000 cycles at 10 A g-1. The electrode design and synthesis suggests large potential in the production of high-performance energy storage devices.

N-doped TiO2 nanotube arrays with uniformly embedded Co x P nanoparticles for high-efficiency hydrogen evolution reaction.

Efficient and stable non-precious metal based electrocatalysts are crucial to the hydrogen evolution reaction (HER) in renewable energy conversion. Herein, Co x P nanoparticles (NPs) are uniformly embedded in N-doped TiO2 nanotube arrays (Co x P/N-TiO2 NTAs) by low-temperature phosphorization of the precursor of metallic cobalt NPs embedded in N-doped TiO2 NTAs (Co/N-TiO2 NTAs) which were fabricated by phase separation of CoTiO3 NTAs in ammonia. Owing to the abundant exposed surface active sites of Co x P NPs, tight contact between the Co x P NPs and TiO2 NTAs, fast electron transfer in N-doped TiO2, and channels for effective diffusion of ions and H2 bubbles in the tubular structure, the Co x P/N-TiO2 NTAs have excellent electrocatalytic activity in HER exemplified by a low overpotential of 180 mV at 10 mA cm-2 and small Tafel slope of 51 mV dec-1 in 0.5 M H2SO4. The catalyst also shows long-term cycling stability and is a promising non-precious metal catalyst for HER.

In Situ Synthesis of MoP Nanoflakes Intercalated N-Doped Graphene Nanobelts from MoO3 -Amine Hybrid for High-Efficient Hydrogen Evolution Reaction.

Molybdenum phosphide (MoP) is a promising non-noble-metal electrocatalyst in the hydrogen evolution reaction (HER), but practical implementation is impeded by the sluggish HER kinetics and poor chemical stability. Herein, a novel high-efficiency HER electrocatalyst comprising MoP nanoflakes intercalated nitrogen-doped graphene nanobelts (MoP/NG), which are synthesized by one-step thermal phosphiding organic-inorganic hybrid dodecylamine (DDA) inserted MoO3 nanobelts, is reported. The intercalated DDA molecules are in situ carbonized into the NG layer and the sandwiched MoO3 layer is converted into MoP nanoflakes which are intercalated between the NG layers forming the alternatingly stacked MoP/NG hybrid nanobelts. The MoP nanoflakes provide abundant edge sites and the sandwiched MoP/NG hybrid enables rapid ion/electron transport thus yielding excellent electrochemical activity and stability for HER. The MoP/NG shows a low overpotential of 94 mV at 10 mA cm-2 , small Tafel slope of 50.1 mV dec-1 , and excellent electrochemical stability with 99.5% retention for over 22 h.