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Suitable biomaterials with seed cells have promising potential to repair bone defects. However, bone marrow mesenchymal stem cells (BMSCs), one of the most common seed cells used in tissue engineering, cannot differentiate efficiently and accurately into functional osteoblasts. In view of this, a new tissue engineering technique combined with BMSCs and scaffolds is a major task for bone defect repair. Lentiviruses interfering with miR-136-5p or Smurf1 expression were transfected into BMSCs. The effects of miR-136-5p or Smurf1 on the osteogenic differentiation (OD) of BMSCs were evaluated by measuring alkaline phosphatase activity and calcium deposition. Then, the targeting relationship between miR-136-5p and Smurf1 was verified by bioinformatics website analysis and dual luciferase reporter assay. Then, a rabbit femoral condyle bone defect model was established. miR-136-5p/BMSCs/ß-TCP scaffold was implanted into the defect, and the repair of the bone defect was detected by Micro-CT and HE staining. Elevating miR-136-5p-3p or suppressing Smurf1 could stimulate OD of BMSCs. miR-136-5p negatively regulated Smurf1 expression. Overexpressing Smurf1 reduced the promoting effect of miR-136-5p on the OD of BMSCs. miR-136-5p/BMSCs/ß-TCP could strengthen bone density in the defected area and accelerate bone repair. SmurF1-targeting miR-136-5p-modified BMSCs combined with 3D-printed ß-TCP scaffolds can strengthen osteogenic activity and alleviate bone defects.
Asunto(s)
Fosfatos de Calcio , Células Madre Mesenquimatosas , MicroARNs , Osteogénesis , Impresión Tridimensional , Andamios del Tejido , Ubiquitina-Proteína Ligasas , MicroARNs/genética , MicroARNs/metabolismo , Células Madre Mesenquimatosas/metabolismo , Animales , Andamios del Tejido/química , Conejos , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Fosfatos de Calcio/química , Diferenciación Celular , Ingeniería de Tejidos/métodos , Masculino , Regeneración Ósea/genéticaRESUMEN
Hydrogen obtained from electrochemical water splitting is the most promising clean energy carrier, which is hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Thus, the development of an efficient OER electrocatalyst using nonprecious 3d transition elements is desirable. Multielement synergistic effect and lattice oxygen oxidation are two well-known mechanisms to enhance the OER activity of catalysts. The latter is generally related to the high valence state of 3d transition elements leading to structural destabilization under the OER condition. We have found that Al doping in nanosheet Ni-Fe hydroxide exhibits 2-fold advantage: (1) a strong enhanced OER activity from 277 mV to 238 mV at 10 mA cm-2 as the Ni valence state increases from Ni3.58+ to Ni3.79+ observed from in situ X-ray absorption spectra. (2) Operational stability is strengthened, while weakness is expected since the increased NiIV content with 3d8L2 (L denotes O 2p hole) would lead to structural instability. This contradiction is attributed to a reduced lattice oxygen contribution to the OER upon Al doping, as verified through in situ Raman spectroscopy, while the enhanced OER activity is interpreted as an enormous gain in exchange energy of FeIV-NiIV, facilitated by their intersite hopping. This study reveals a mechanism of Fe-Ni synergy effect to enhance OER activity and simultaneously to strengthen operational stability by suppressing the contribution of lattice oxygen.
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The electrochemical reduction of CO2 to CO is a powerful approach to achieving carbon neutrality. Herein, we report a five-nuclear copper cluster-based metal-azolate framework CuTz-1 as an electrocatalyst for the electrochemical CO2 reduction reaction. It achieved a faradaic efficiency (FE) of 62.7% for yielding CO with a partial current density of -35.1 mA cm-2 in flow cell device, which can be preserved for more than ten hours with negligible changes of the current density and FE(CO). Studies of electrocatalytic mechanism studies revealed that the distance of Cu-N was increased, and the coordination number of the Cu ion was reduced, while the oxidation state of Cu was decreased after the electrocatalysis. These findings offer valuable insights into structural changes that influence the performance of the catalyst during the process of the electrochemical reduction of CO2 process.
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The solid oxide electrolysis cell (SOEC) is an advanced electrochemical device with a promising future in reducing CO2 emissions. Currently, the insufficient oxygen evolution reaction activity in conventional anode materials severely restricts the development of electrolytic CO2. Herein, the PNCO-LSC composite oxygen electrode was exploited by impregnating Pr2Ni0.8Co0.2O4+δ (PNCO) on the surface of La0.6Sr0.4CoO3-δ (LSC) oxygen electrode. The results of electrochemical tests and various physicochemical characterizations indicate that the infiltration of PNCO can lead to a significant improvement in the performance of the cell for CO2 electroreduction by increasing the surface oxygen exchange. The current density of the PNCO-LSC oxygen electrode infiltrated twice at 800 °C and 1.5 V reaches 0.917 A cm-2, which is about 40% higher than that of the bare LSC oxygen electrode. In addition, the single cell did not show significant degradation in a long-term stability test at a current density of 0.4 A cm-2 for 100 h of electrolysis. Therefore, the PNCO-LSC composite oxygen electrode material is effective in enhancing electrolytic CO2 performance.
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Reversible solid oxide cells (rSOCs) have significant potential as efficient energy conversion and storage systems. Nevertheless, the practical application of their conventional air electrodes, such as La0.8Sr0.2MnO3-δ (LSM), Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), and PrBa0.8Ca0.2Co2O5+δ (PBCC), remains unsatisfactory due to interface delamination during prolonged electrochemical operation. Using micro-focusing X-ray absorption spectroscopy (µ-XAS), a decrease (increase) in the co-valence state from the electrode surface to the electrode/electrolyte interface is observed, leading to the above delamination. Utilizing the one-pot method to incorporate an oxygen-vacancy-enriched CeO2 electrode into these air electrodes, the uniform distribution of the Co valence state is observed, alleviating the structural delamination. PBCC-CeO2 electrodes exhibited a degradation rate of 0.095 mV h-1 at 650 °C during a nearly 500-h test as compared with 0.907 mV h-1 observed during the 135-h test for PBCC. Additionally, a remarkable increase in electrolysis current density from 636 to 934 mA cm-2 under 1.3 V and a maximum power density from 912 to 989 mW cm-2 upon incorporating CeO2 into PBCC is also observed. BSCF-CeO2 and LSM-CeO2 also show enhanced electrochemical performance and prolonged stability as compared to BSCF and LSM. This work offers a strategy to mitigate the structural delamination of conventional electrodes to boost the performance of rSOCs.
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Modulating the coordination environment of the metal active center is an effective method to boost the catalytic performances of metal-organic frameworks (MOFs) for oxygen evolution reaction (OER). However, little attention has been paid to the halogen effects on the ligands engineering. Herein, a series of MOFs XâFeNi-MOFs (X = Br, Cl, and F) is constructed with different coordination microenvironments to optimize OER activity. Theoretical calculations reveal that with the increase in electronegativity of halogen ions in terephthalic acid molecular (TPA), the Bader charge of Ni atoms gets larger and the Ni-3d band center and O-2p bands move closer to the Fermi level. This indicates that an increase in ligand negativity of halogen ions in TPA can promote the adsorption ability of catalytic sites to oxygen-containing intermediates and reduce the activation barrier for OER. Experimental also demonstrates that FâFeNi-MOFs exhibit the highest catalytic activity with an ultralow overpotential of 218 mV at 10 mA cm-2, outperforming most otate-of-the-art Fe/Co/Ni-based MOFs catalysts, and the enhanced mass activity by seven times compared with that for the sample before ligands engineering. This work opens a new avenue for the realization of the modulation of NiFeâO bonding by halogen ion in TPA and improves the OER performance of MOFs.
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With the rapid development of nuclear energy, problems with uranium supply chain and nuclear waste accumulation have motivated researchers to improve uranium separation methods. Here we show a paradigm for such goal based on the in-situ formation of π-f conjugated two-dimensional uranium-organic framework. After screening five π-conjugated organic ligands, we find that 1,3,5-triformylphloroglucinol would be the best one to construct uranium-organic framework, thus resulting in 100% uranium removal from both high and low concentration with the residual concentration far below the WHO drinking water standard (15 ppb), and 97% uranium capture from natural seawater (3.3 ppb) with a record uptake efficiency of 0.64 mg·g-1·d-1. We also find that 1,3,5-triformylphloroglucinol can overcome the ion-interference issue such as the presence of massive interference ions or a 21-ions mixed solution. Our finds confirm the superiority of our separation approach over established ones, and will provide a fundamental molecule design for separation upon metal-organic framework chemistry.
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Crystalline organic-inorganic hybrids, which exhibit colorimetric responses to ionizing radiation, have recently been recognized as promising alternatives to conventional X-ray dosimeters. However, X-ray-responsive organic-inorganic hybrids are scarce and the strategy to fine-tune their detection sensitivity remains elusive. Herein, an unprecedented mixed-ligand strategy is reported to modulate the X-ray detection efficacy of organic-inorganic hybrids. Deliberately blending the stimuli-responsive terpyridine carboxylate ligand (tpc- ) and the auxiliary pba- group with different ratios gives rise to two OD thorium-bearing clusters (Th-102 and Th-103) and a 1D coordination polymer (Th-104). Notably, distinct X-ray sensitivity is evident as a function of molar ratio of the tpc- ligand, following the trend of Th-102 > Th-103 > Th-104. Moreover, Th-102, which is exclusively built from the tpc- ligands with the highest degree of π-π interactions, exhibits the most sensitive radiochromic and fluorochromic responses toward X-ray with the lowest detection limit of 1.5 mGy. The study anticipates that this mixed-ligand strategy will be a versatile approach to tune the X-ray sensing efficacy of organic-inorganic hybrids.
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The photoluminescent properties of lanthanide complexes have been thoroughly investigated; however, there have been much fewer studies showcasing their potential use in ionizing radiation detection. In this work, we delve into the photo- and radio-induced luminescence of a series of lanthanide-bearing organic-inorganic hybrids and their potential as a platform for X-ray scintillation and imaging. The judicious synergy between lanthanide cations and 2,6-di(1H-pyrazol-1-yl)isonicotinate (bppCOO-) ligands affords six new materials with three distinct structures. Notably, Eu-bppCOO-1 and Tb-bppCOO-2 display sharp fingerprint X-ray-excited luminescence (XEL), the intensities of which can be linearly correlated with the X-ray dose rates over a broad dynamic range (0.007-4.55â mGy s-1). Moreover, the X-ray sensing efficacies of Eu-bppCOO-1 and Tb-bppCOO-2 were evaluated, showing that Tb-bppCOO-2 features a lower detection limit of 4.06â µGy s-1 compared to 14.55â µGy s-1 of Eu-bppCOO-1. Given the higher X-ray sensitivity and excellent radiation stability of Tb-bppCOO-2, we fabricated a flexible scintillator film for X-ray imaging by embedding finely ground Tb-bppCOO-2 in the polydimethylsiloxane (PDMS) polymer. The resulting scintillator film can be utilized for high-resolution X-ray imaging with a spatial resolution of approximately 7â lp mm-1.
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Protonic ceramic fuel cells with high efficiency and low emissions exhibit high potential as next-generation sustainable energy systems. However, the practical proton conductivity of protonic ceramic electrolytes is still not satisfied due to poor membrane sintering. Here, we show that the dynamic displacement of Y3+ adversely affects the high-temperature membrane sintering of the benchmark protonic electrolyte BaZr0.1Ce0.7Y0.1Yb0.1O3-δ, reducing its conductivity and stability. By introducing a molten salt approach, pre-doping of Y3+ into A-site is realized at reduced synthesis temperature, thus suppressing its further displacement during high-temperature sintering, consequently enhancing the membrane densification and improving the conductivity and stability. The anode-supported single cell exhibits a power density of 663 mW cm-2 at 600 °C and long-term stability for over 2000 h with negligible performance degradation. This study sheds light on protonic membrane sintering while offering an alternative strategy for protonic ceramic fuel cells development.
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A novel radio-photoluminescence material featuring fluorochromic responses toward UV or X-ray irradiation has been obtained. Such a unique monomer- to excimer-based luminescence transition allows for dosimetry of ionizing radiation in a ratiometric manner. Rather than quenching the luminescence, the radiation-induced radical species of Th-105 boost the excimer emission, rendering it as a rare material possessing radical-excimers.
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MXene-supported noble metal alloy catalysts exhibit remarkable electrocatalytic activity in various applications. However, there is no facile one-step method for synthesizing these catalysts, because the synthesis of MXenes requires a strongly oxidizing environment and the preparation of platinum nanoalloys requires a strongly reducing environment and high temperatures. Hence, achieving coupling in one step is extremely challenging. In this paper, a straightforward one-step molten salt method for preparing MXene-supported platinum nanoalloy catalysts is proposed. The molten salt acts as the reaction medium to dissolve the transition metals and platinum ions at high temperatures. Transition metal ions oxidize the A-site element from its MAX precursor at high temperatures, and the resulting transition metals further reduce platinum ions to form alloys. By coupling Al oxidation and platinum ion reduction using a molten salt solvent, this method directly converts Ti3 AlC2 to a Pt-M@Ti3 C2 Tx catalyst (where M denotes the transition metal). It further offers the possibility of extending the Pt-M phase to binary, ternary, or quaternary platinum-containing nanoalloys and converting the Al-containing MAX phase to Ti2 AlC and Ti3 AlCN. Due to the strong interfacial interaction, the as-prepared Pt-Co@Ti3 C2 Tx is superior to commercial Pt/C (20 wt.%) in the hydrogen evolution reaction.
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Actinide-bearing metal-organic frameworks (MOFs) encompass intriguing structures and properties, but the radioactivity of actinide cripples their applications. Herein, we have constructed a new thorium-based MOF (Th-BDAT) as a bifunctional platform for the adsorption and detection of radioiodine, a more radioactive fission product that can readily spread through the atmosphere in its molecular form or via solution as anionic species. The iodine capture within the framework of Th-BDAT from both the vapor phase and the cyclohexane solution has been verified, showing that Th-BDAT features maximum I2 adsorption capacities (Qmax) of 959 and 1046 mg/g, respectively. Notably, the Qmax of Th-BDAT toward I2 from cyclohexane solution ranks among the highest value for Th-MOFs reported to date. Furthermore, incorporating highly extended and π-electron-rich BDAT4- ligands renders Th-BDAT as a luminescent chemosensor whose emission can be selectively quenched by iodate with a detection limit of 1.367 µM. Our findings thus foreshadow promising directions that might unlock the full potential of actinide-based MOFs from the point of view of practical application.
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Post-synthetic linker installation in a single-crystal-to-single-crystal manner was crystallographically demonstrated in thorium-based metal-organic frameworks (Th-MOFs), not only leading to the discovery of an extremely rare framework de-interpenetration, but also representing an unprecedented strategy for boosting iodine adsorption capacity.
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Designing efficient catalyst for the oxygen evolution reaction (OER) is of importance for energy conversion devices. The anionic redox allows formation of O-O bonds and offers higher OER activity than the conventional metal sites. Here, we successfully prepare LiNiO2 with a dominant 3d8L configuration (L is a hole at O 2p) under high oxygen pressure, and achieve a double ligand holes 3d8L2 under OER since one electron removal occurs at O 2p orbitals for NiIII oxides. LiNiO2 exhibits super-efficient OER activity among LiMO2, RMO3 (M = transition metal, R = rare earth) and other unary 3d catalysts. Multiple in situ/operando spectroscopies reveal NiIIIâNiIV transition together with Li-removal during OER. Our theory indicates that NiIV (3d8L2) leads to direct O-O coupling between lattice oxygen and *O intermediates accelerating the OER activity. These findings highlight a new way to design the lattice oxygen redox with enough ligand holes created in OER process.
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Membranes with fast and selective ion transport are essential for separations and electrochemical energy conversion and storage devices. Metal-coordinated polymers are promising for fabricating ion-conducting membranes with molecular channels, however, the structures and ion transport channels remain poorly understood. Here, we reported mechanistic insights into the structures of metal-ion coordinated polybenzimidazole membranes and the preferential K+ transport. Molecular dynamics simulations suggested that coordination between metal ions and polybenzimidazole expanded the free volume, forming subnanometre molecular channels. The combined physical confinement in nanosized channels and electrostatic interactions of membranes resulted in a high K+ transference number up to 0.9 even in concentrated salt and alkaline solutions. The zinc-coordinated polybenzimidazole membrane enabled fast transport of charge carriers as well as suppressed water migration in an alkaline zinc-iron flow battery, enabling the battery to operate stably for over 340 hours. This study provided an alternative strategy to regulate the ion transport properties of polymer membranes by tuning polymer chain architectures via metal ion coordination.
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Developing ultraviolet (UV) radiation sensors featuring high sensitivity, ease of operation, and rapid readout is highly desired in diverse fields. However, the strategies to enhance sensitivity of UV detection remain limited particularly for photochromic materials, which show colorimetric response toward UV irradiation. Guided by our initial goal of facilitating easier handling, we formulated a viologen derivative ([H2L]-SC) incorporating hydrogel-based UV sensor which not only inherits the photochromism of [H2L]-SC but also engenders an unprecedented reversible photoelectrochromic response that is absent in either [H2L]-SC or hydrogel alone. Judicious synergy between photochromic [H2L]-SC and polyacrylamide (PAM) converts the colorimetric response of [H2L]-SC into the electrical resistance change of [H2L]-SC@PAM, which amplifies the UV sensitivity of [H2L]-SC by 2 orders of magnitude. Explicitly, the limit of detection (LOD) for UV decreases from 296.3 mJ/cm2 based on the UV-vis absorption spectra of [H2L]-SC to 2.83 mJ/cm2 derived from the resistance variation of [H2L]-SC@PAM. Moreover, linear correlation between the resistance reduction rate of [H2L]-SC@PAM and UV dose rate can be established, rendering it as a dual platform for quantifying both the accumulated UV dose and the instant dose rate. In addition, the proposed strategy based on constructing photoelectrochromic hybrids offers a new pathway to boost the UV sensitivity that could be universal for other photochromic materials.
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Hidrogeles , Viológenos , Rayos UltravioletaRESUMEN
Simple synthetic modulation based on thorium nitrate and tris((4-carboxyl)phenylduryl)amine (H3TCBPA) gives rise to a new thorium-based metal-organic framework, Th-TCBPA, which features excellent hydrolytic and thermal stabilities. Incorporating electron-rich TCBPA3- linkers not only endows Th-TCBPA with high adsorption capacity toward radioiodine vapor, but also makes it a luminescence sensor for the highly sensitive and selective detection of Cr(VI) anions.
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Previous reports have confirmed that crude saponins (ginsenosides) in Panax ginseng have a preventive effect on chemotherapy-induced intestinal injury. However, the protective effects and possible mechanisms of ginsenoside Re (G-Re, a maker saponin in ginseng) against chemotherapy-induced intestinal damage have not been thoroughly studied. In this work, a series of experiments in vivo and in vitro on the intestinal toxicity caused by cisplatin have been designed to verify the improvement effect of G-Re, focusing on the levels of Wnt3a and [Formula: see text]-catenin. Mice were intragastric with G-Re for 10 days, and intestinal injury was induced by intraperitoneal administration of cisplatin at a dose of 20 mg/kg. Histopathology, gastrointestinal digestive enzyme activities, inflammatory cytokines, and oxidative status were evaluated to investigate the protective effect. Furthermore, in IEC-6 cells, G-Re statistically reverses cisplatin-induced oxidative damage and cytotoxicity. The TUNEL and Hoechst 33258 staining demonstrated that G-Re possesses protective effects in cisplatin-induced apoptosis. Additionally, pretreatment with G-Re significantly alleviated the apoptosis via inhibition of over-expressions of B-associated X (Bax), as well as the caspase family members, such as caspase 3 and 9, respectively, in vivo and in vitro. Notably, western blotting results showed that G-Re treatment decreased Wnt3a, Glycogen synthase kinase [Formula: see text] (GSK-[Formula: see text]), and [Formula: see text]-catenin expression, suggesting that nuclear accumulation of [Formula: see text]-catenin was attenuated, thereby inhibiting the activation of GSK-[Formula: see text]-dependent Wnt/[Formula: see text]-catenin signaling, which was consistent with our expected results. Therefore, the above evidence suggested that G-Re may be a candidate drug for the treatment of intestinal injury.
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Antineoplásicos , Ginsenósidos , Saponinas , Ratones , Animales , Ginsenósidos/farmacología , Cisplatino/toxicidad , Vía de Señalización Wnt , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Saponinas/farmacología , Antineoplásicos/farmacología , Cateninas/metabolismo , Cateninas/farmacología , beta Catenina/metabolismoRESUMEN
Monitoring and shielding of X-ray radiation are of paramount importance across diverse fields. However, they are frequently realized in separate protocols and a single material integrating both functions remained elusive. Herein, a hexanuclear cluster [Th6 (µ3 -OH)4 (µ3 -O)4 (H2 O)6 ](pba)6 (HCOO)6 (Th-pba-0D) incorporating high-Z thorium cations and 3-(pyridin-4-yl)benzoate ligands that can function as a brand-new dual-module platform for visible detection and efficient shielding of ionizing radiation is demonstrated. Th-pba-0D exhibits rather unique reversible radiochromism upon alternating X-ray and UV irradiation. Moreover, the millimeter scale crystal size of Th-pba-0D renders the penetration depth of X-ray visible to naked eye and leads to the unearthing of its high X-ray attenuation efficiency. Indeed, the shielding efficacy of Th-pba-0D is comparable to that of lead glass containing 40% PbO, and a Th-pba-0D pellet with a thickness of merely 1.2 mm can shield 99.73% X-ray (16 keV). These studies portend the possible utilization of thorium-bearing materials as a bifunctional platform for radiation detection and shielding.