Mechanism of dexmedetomidine protection against cisplatin induced acute kidney injury in rats.

OBJECTIVE: This study explored the molecular mechanisms by which dexmedetomidine (Dex) alleviates cisplatin (CP)-induced acute kidney injury (AKI) in rats. METHODS: CP-induced AKI models were established, and Dex was intraperitoneally injected at different concentrations into rats in the model groups. Subsequently, rats were assigned to the control, CP, CP + Dex 10 µg/kg, and CP + Dex 25 µg/kg groups. After weighing the kidneys of the rats, the kidney arterial resistive index was calculated, and CP-induced AKI was evaluated. In addition, four serum biochemical indices were measured: histopathological damage in rat kidneys was detected; levels of inflammatory factors, interleukin (IL)-1ß, IL-18, IL-6, and tumor necrosis factor alpha, in kidney tissue homogenate of rats were assessed through enzyme-linked immunosorbent assay (ELISA); and levels of NLRP-3, caspase-1, cleaved caspase-1, gasdermin D (GSDMD), and GSDMD-N in kidney tissues of rats were determined via western blotting. RESULTS: Dex treatment reduced nephromegaly and serum clinical marker upregulation caused by CP-induced AKI. In addition, hematoxylin and eosin staining revealed that Dex treatment relieved CP-induced kidney tissue injury in AKI rats. ELISA analyses demonstrated that Dex treatment reduced the upregulated levels of proinflammatory cytokines in the kidney tissue of AKI rats induced by CP, thereby alleviating kidney tissue injury. Western blotting indicated that Dex alleviated CP-induced AKI by inhibiting pyroptosis mediated by NLRP-3 and caspase-1. CONCLUSION: Dex protected rats from CP-induced AKI, and the mechanism may be related to NLRP-3/Caspase-1-mediated pyroptosis.

A Versatile Theranostic Nanoplatform with Aggregation-Induced Emission Properties: Fluorescence Monitoring, Cellular Organelle Targeting, and Image-Guided Photodynamic Therapy.

Photosensitizers (PSs) play a key role in the photodynamic therapy (PDT) of tumors. However, commonly used PSs are prone to intrinsic fluorescence aggregation-caused quenching and photobleaching; this drawback severely limits the clinical application of PDT, necessitating new phototheranostic agents. Herein, a multifunctional theranostic nanoplatform (named TTCBTA NP) is designed and constructed to achieve fluorescence monitoring, lysosome-specific targeting, and image-guided PDT. TTCBTA with a twisted conformation and D-A structure is encapsulated in amphiphilic Pluronic F127 to form nanoparticles (NPs) in ultrapure water. The NPs exhibit biocompatibility, high stability, strong near-infrared emission, and desirable reactive oxygen species (ROSs) production capacity. The TTCBTA NPs also show high-efficiency photo-damage, negligible dark toxicity, excellent fluorescent tracing, and high accumulation in lysosome for tumor cells. Furthermore, TTCBTA NPs are used to obtain fluorescence images with good resolution of MCF-7 tumors in xenografted BALB/c nude mice. Crucially, TTCBTA NPs present a strong tumor ablation ability and image-guided PDT effect by generating abundant ROSs upon laser irradiation. These results demonstrate that the TTCBTA NP theranostic nanoplatform may enable highly efficient near-infrared fluorescence image-guided PDT.

Stabilizing Cobalt Single Atoms via Flexible Carbon Membranes as Bifunctional Electrocatalysts for Binder-Free Zinc-Air Batteries.

Single-atom catalysts with high activity and efficient atom utilization have great potential in the electrocatalysis field, especially for rechargeable zinc-air batteries (ZABs). However, it is still a serious challenge to rationally construct a single-atom catalyst with satisfactory electrocatalytic activity and long-term stability. Here, we simultaneously realize the atomic-level dispersion of cobalt and the construction of carbon nanotube (CNT)-linked N-doped porous carbon nanofibers (NCFs) via an electrospinning strategy. In this hierarchical structure, the Co-N4 sites provide efficient oxygen reduction/evolution electrocatalytic activity, the porous architectures of NCFs guarantee the active site's accessibility, and the interior CNTs enhance the flexibility and mechanical strength of porous fibers. As a binder-free air cathode, the as-prepared catalysts deliver superdurability of 600 h at 10 mA cm-2 for aqueous ZABs and considerable flexibility and a small voltage gap for all-solid-state ZABs. This work provides an effective single-atom design/nanoengineering for superdurable zinc-air batteries.

Enhancing Built-in Electric Fields for Efficient Photocatalytic Hydrogen Evolution by Encapsulating C60 Fullerene into Zirconium-Based Metal-Organic Frameworks.

High-efficiency photocatalysts based on metal-organic frameworks (MOFs) are often limited by poor charge separation and slow charge-transfer kinetics. Herein, a novel MOF photocatalyst is successfully constructed by encapsulating C60 into a nano-sized zirconium-based MOF, NU-901. By virtue of host-guest interactions and uneven charge distribution, a substantial electrostatic potential difference is set-up in C60 @NU-901. The direct consequence is a robust built-in electric field, which tends to be 10.7 times higher in C60 @NU-901 than that found in NU-901. In the catalyst, photogenerated charge carriers are efficiently separated and transported to the surface. For example, photocatalytic hydrogen evolution reaches 22.3 mmol g-1 h-1 for C60 @NU-901, which is among the highest values for MOFs. Our concept of enhancing charge separation by harnessing host-guest interactions constitutes a promising strategy to design photocatalysts for efficient solar-to-chemical energy conversion.

In Situ X-ray Absorption Spectroscopy of Metal/Nitrogen-doped Carbons in Oxygen Electrocatalysis.

Metal/nitrogen-doped carbons (M-N-C) are promising candidates as oxygen electrocatalysts due to their low cost, tunable catalytic activity and selectivity, and well-dispersed morphologies. To improve the electrocatalytic performance of such systems, it is critical to gain a detailed understanding of their structure and properties through advanced characterization. In situ X-ray absorption spectroscopy (XAS) serves as a powerful tool to probe both the active sites and structural evolution of catalytic materials under reaction conditions. In this review, we firstly provide an overview of the fundamental concepts of XAS and then comprehensively review the setup and application of in situ XAS, introducing electrochemical XAS cells, experimental methods, as well as primary functions on catalytic applications. The active sites and the structural evolution of M-N-C catalysts caused by the interplay with electric fields, electrolytes and reactants/intermediates during the oxygen evolution reaction and the oxygen reduction reaction are subsequently discussed in detail. Finally, major challenges and future opportunities in this exciting field are highlighted.

Superdurable Bifunctional Oxygen Electrocatalyst for High-Performance Zinc-Air Batteries.

The development of high-efficiency and durable bifunctional electrocatalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for the widespread application of rechargeable zinc-air (Zn-air) batteries. This calls for rational screening of targeted ORR/OER components and precise control of their atomic and electronic structures to produce synergistic effects. Here, we report a Mn-doped RuO2 (Mn-RuO2) bimetallic oxide with atomic-scale dispersion of Mn atoms into the RuO2 lattice, which exhibits remarkable activity and super durability for both the ORR and OER, with a very low potential difference (ΔE) of 0.64 V between the half-wave potential of ORR (E1/2) and the OER potential at 10 mA cm-2 (Ej10) and a negligible decay of E1/2 and Ej10 after 250 000 and 30 000 CV cycles for ORR and OER, respectively. Moreover, Zn-air batteries using the Mn-RuO2 catalysts exhibit a high power density of 181 mW cm-2, low charge/discharge voltage gaps of 0.69/0.96/1.38 V, and ultralong lifespans of 15 000/2800/1800 cycles (corresponding to 2500/467/300 h operation time) at a current density of 10/50/100 mA cm-2, respectively. Theoretical calculations reveal that the excellent performances of Mn-RuO2 is mainly due to the precise optimization of valence state and d-band center for appropriate adsorption energy of the oxygenated intermediates.

RuCoOx Nanofoam as a High-Performance Trifunctional Electrocatalyst for Rechargeable Zinc-Air Batteries and Water Splitting.

Designing high-performance trifunctional electrocatalysts for ORR/OER/HER with outstanding activity and stability for each reaction is quite significant yet challenging for renewable energy technologies. Herein, a highly efficient and durable trifunctional electrocatalyst RuCoOx is prepared by a unique one-pot glucose-blowing approach. Remarkably, RuCoOx catalyst exhibits a small potential difference (ΔE) of 0.65 V and low HER overpotential of 37 mV (10 mA cm-2), as well as a negligible decay of overpotential after 200 000/10 000/10 000 CV cycles for ORR/OER/HER, all of which show overwhelming superiorities among the advanced trifunctional electrocatalysts. When used in liquid rechargeable Zn-air batteries and water splitting electrolyzer, RuCoOx exhibits high efficiency and outstanding durability even at quite large current density. Such excellent performance can be attributed to the rational combination of targeted ORR/OER/HER active sites into one electrocatalyst based on the double-phase coupling strategy, which induces sufficient electronic structure modulation and synergistic effect for enhanced trifunctional properties.

Synthesis and Structural Studies of Two Paramagnetic Metallofullerenes with Isomeric C72 Cage.

We synthesized and isolated two paramagnetic metallofullerenes of La@C72 and Y@C72 with different fullerene cages, which were characterized by electron paramagnetic resonance (EPR) spectroscopy and theoretical calculations. DFT calculations disclosed two possible isomers of La/Y@C72 with C72- C2 and C72- C2v cages, both of which have similar thermodynamic stability and one pair of fused pentagons. Their paramagnetic properties were then studied by EPR spectroscopy, and the obtained EPR signals were analyzed with very different hyperfine coupling constants, revealing distinct electron spin distributions for these two species. Furthermore, the experimental coupling constants were compared with those of calculated coupling constants, and comparison results revealed that the produced La@C72 has a C72- C2v cage and Y@C72 has a C72- C2 cage. These studies illustrate that the electron spin can be used as a probe to identify metallofullerene structure due to the susceptibility of spin-metal couplings. The successful isolation and characterizations of La@C72 and Y@C72 with such a small C72 cage reveal their stability that is important for application as paramagnetic molecule materials.

Awaking N-hyperfine couplings in charged yttrium nitride endohedral fullerenes.

The electron spin properties of endohedral metallofullerene molecules have broad potential applications in quantum information and magnetic induction systems due to the high stability and sensitivity. Herein, we synthesized a series of Y3N@C2n (n = 40-44) molecules and studied the hyperfine structures of their anion radicals via ESR measurements and DFT calculations. N-Hyperfine couplings were clearly observed in the ESR spectra of charged Y3N@C80 and Y3N@C86 anion radicals, which are not found in the other metallofullerenes. The ESR results revealed size-dependent spin distributions and hyperfine structures, which are sensitive to subtle changes in the carbon cage and the configuration of the yttrium nitride cluster. BOMD cluster trajectories simulations indicated that the Y3N cluster almost rotates freely in neutral Y3N@C80 but there is a certain degree of limitation in the Y3N@C80 anion.

Real-space imaging for discovering a rotated node structure in metal-organic framework.

Resolving the detailed structures of metal organic frameworks is of great significance for understanding their structure-property relation. Real-space imaging methods could exhibit superiority in revealing not only the local structure but also the bulk symmetry of these complex porous materials, compared to reciprocal-space diffraction methods, despite the technical challenges. Here we apply a low-dose imaging technique to clearly resolve the atomic structures of building units in a metal-organic framework, MIL-125. An unexpected node structure is discovered by directly imaging the rotation of Ti-O nodes, different from the unrotated structure predicted by previous X-ray diffraction. The imaged structure and symmetry can be confirmed by the structural simulations and energy calculations. Then, the distribution of node rotation from the edge to the center of a MIL-125 particle is revealed by the image analysis of Ti-O rotation. The related defects and surface terminations in MIL-125 are also investigated in the real-space images. These results not only unraveled the node symmetry in MIL-125 with atomic resolution but also inspired further studies on discovering more unpredicted structural changes in other porous materials by real-space imaging methods.

Multifunctional Organic Fluorescent Probe with Aggregation-Induced Emission Characteristics: Ultrafast Tumor Monitoring, Two-Photon Imaging, and Image-Guide Photodynamic Therapy.

The development of multifunctional photosensitizers (PSs) with aggregation-induced emission (AIE) properties plays a critical role in promoting the progress of the photodynamic therapy (PDT). In this work, a multifunctional PS (named DSABBT NPs) with AIE activity has been designed and prepared to carry out ultrafast staining, excellent two-photon bioimaging, and high-efficiency image-guided PDT. Simply, DSABBT with AIE characteristic was synthesized by one-step Schiff reaction of 4-(diethylamino)-salicylaldehyde (DSA) and 4,7-bis(4-aminophenyl)-2,1,3-benzothiadiazole (BBT). Then, DSABBT and DSPE-PEG2000-cRGD generate nanoparticles (NPs) easily in an ultrapure water/tetrahydrofuran mixture through a facile nanoprecipitation at room temperature. We found that DSABBT NPs exhibit bright solid-state fluorescence with large stokes shifts (180 nm) and two-photon absorption cross-section (1700 GM). Importantly, DSABBT NPs exhibited excellent ability of ultrafast staining and two-photon imaging, which can readily label suborganelles by subtly shaking the living cells for 5 s under mild conditions. Moreover, DSABBT NPs displayed high singlet oxygen (1O2) generation capacity and remarkable image-guided PDT efficiency. Therefore, DSABBT NPs can act as the promising candidate for multifunctional PSs, which can destroy cancer cells and block malignant tumor growth via the production of reactive oxygen species upon irradiation conditions. These outcomes provide us with a selectable strategy for developing multifunctional theranostic systems.

Crystallographic evidence and spin activation for the Russian-doll-type metallofullerene Sc4C2@C80.

We report unambiguous crystallographic evidence for the Russian-doll-type metallofullerene Sc4C2@Ih-C80. 45Sc NMR further demonstrates the tetrahedron arrangement of the Sc4C2 cluster. Moreover, the electrochemical test reveals the stable oxidation state of Sc4C2@C80. Hence, the Sc4C2@C80 cation radical was studied by electron spin resonance spectroscopy. These results provide better understanding for the previously less-explored Sc4C2@C80.

Carnosine-Modified Fullerene as a Highly Enhanced ROS Scavenger for Mitigating Acute Oxidative Stress.

Fullerenes are known as highly efficient scavengers for reactive oxygen species (ROSs). In this study, a carnosine-modified fullerene derivative (C60-Car) was synthesized via a one-step nucleophilic addition reaction. C60-Car forms nanoparticles (NPs) readily in water at neutral pH and room temperature through self-assembly. The C60-Car NPs were found to possess good water solubility, biocompatibility, and excellent ROSs scavenging capability. The scavenging efficiency of ROSs is as high as 92.49% and significantly better than that of hydroxyfullerene (C60-OH NPs, 70.92%) and l-carnosine. Furthermore, C60-Car NPs showed strong cytoprotective ability against H2O2-induced damage to the normal human fetal hepatocyte cells (L-02) and human epidermal keratinocytes-adult (HEK-a) cells at a lower concentration of 2.5 µM. In contrast, C60-OH NPs showed a minor cytoprotective effect on cells at a high concentration of 10 µM. The excellent properties of such a fullerene derivative, C60-Car, can be attributed largely to the involvement of l-carnosine with biological activity and antioxidant property, which make it better for biomedicine, and it may provide a new strategy for mitigating acute oxidative stress based on fullerene materials.

A metabonomic approach to early prognostic evaluation of experimental sepsis by (1)H NMR and pattern recognition.

This study proposes an NMR-based metabonomic approach to early prognostic evaluation of sepsis. Forty septic rats receiving cecal ligation and puncture (CLP) were divided into the surviving group and nonsurviving group on day 6, while 20 sham-operated rats served as the control group. Serum samples were collected from septic and sham-operated rats at 12 h after surgery and analyzed using (1)H NMR spectroscopy. Orthogonal partial least squares (OPLS) were applied and showed clustering according to predefined groups, indicating that NMR-based metabolic profiling could reveal pathologic characteristics in the serum of sham-operated, surviving, and nonsurviving septic rats. In addition, six characteristic metabolites including lactate, alanine, acetate, acetoacetate, hydroxybutyrate, and formate, which are mainly involved in energy metabolism, changed markedly in septic rats, especially in the nonsurvivors. Using these metabolites, a predictive model for prognostic evaluation of sepsis was constructed using a radial basis function neural network (RBFNN) with a prediction accuracy of about 87% by test samples. The results indicated that the NMR-based metabonomic approach is a potential technique for the early prognostic evaluation of sepsis.

Construction of a short metallofullerene-peapod with a spin probe.

A short metallofullere-peapod of Y2@C79N⊂[4]CHBC was constructed. The strong confinement effect from the large π-extended [4]CHBC nanoring induces molecular orientation of the wrapped Y2@C79N, which can be sensed by a Y2@C79N spin probe. The low susceptibility of the spin phase memory time (Tm) for the Y2@C79N spin was also found in a confined space.

A luminescent single-molecule magnet of dimetallofullerene with cage-dependent properties.

It is important to explore luminescent single-molecule magnets (SMMs) to promote their application in high-density data storage. Herein, we report two dimetallofullerenes of DyEr@C82 isomers, which exhibit cage-dependent single-molecule magnet behavior and photoluminescence properties. DyEr@C82 isomers were characterized with a Cs and C3v cage symmetry by UV-vis-NIR spectroscopy and single-crystal X-ray diffraction analysis. Magnetic results revealed that DyEr@C3v-C82 displays SMM behavior below 3 K, whereas DyEr@Cs-C82 is a paramagnet. In addition, photoluminescence (PL) was also observed for both of these two isomers, whose peak patterns are different. Theoretical calculations revealed the presence of a one-electron-two-center Dy-Er bond in these two isomers, and different electronic structures of DyEr@Cs-C82 and DyEr@C3v-C82, which agrees well with the experimental results. These results show that dimetallofullerenes are promising magneto-luminescent materials with varied properties.

Exciton funneling in light-harvesting organic semiconductor microcrystals for wavelength-tunable lasers.

Organic solid-state lasers are essential for various photonic applications, yet current-driven lasing remains a great challenge. Charge transfer (CT) complexes formed with p-/n-type organic semiconductors show great potential in electrically pumped lasers, but it is still difficult to achieve population inversion owing to substantial nonradiative loss from delocalized CT states. Here, we demonstrate the lasing action of CT complexes based on exciton funneling in p-type organic microcrystals with n-type doping. The CT complexes with narrow bandgap were locally formed and surrounded by the hosts with high-lying energy levels, which behave as artificial light-harvesting systems. Excitation light energy captured by the hosts was delivered to the CT complexes, functioning as exciton funnels to benefit lasing actions. The lasing wavelength of such composite microcrystals was further modulated by varying the degree of CT. The results offer a comprehensive understanding of exciton funneling in light-harvesting systems for the development of high-performance organic lasing devices.

Triptycene molecular rotors mounted on metallofullerene Sc3C2@C80 and their spin-rotation couplings.

Molecular machines have received considerable attention due to their various applications. Except for mechanical motion, it is essential to design advanced molecular machines with integrated functions. In this study, the triptycene rotor has been covalently linked to paramagnetic metallofullerene Sc3C2@C80 with an unpaired electron spin, resulting in a coupled system between spin flip and rotor speed. Two types of triptycene rotors were employed, one is pristine triptycene and another one has a sterically hindered methyl group. Temperature-dependent electron paramagnetic resonance (EPR) spectroscopy revealed that spin-rotor coupling can be modulated by the rotation speed of triptycene rotors, which was further illustrated by variable-temperature 1H NMR. EPR simulation revealed that the rotations of the attached triptycene rotors can greatly influence the spin relaxation and spin-metal hyperfine couplings of Sc3C2@C80, realizing remote control on neighboring electron spin states. These findings of the coupled system between the molecular rotor and spin flip would provide an approach to design advanced molecular machines with magnetic function.

Optically Controlled Molecular Metallofullerene Magnetism via an Azobenzene-Functionalized Metal-Organic Framework.

Molecular magnets with optically controlled property have significant applications in data storage and quantum information processing. Herein, we report the optically controlled molecular magnetism of endohedral metallofullerenes, Sc3C2@C80 and DySc2N@C80, by incarcerating them into the pores of a photoswitchable azobenzene-functionalized metal-organic framework (MOF) (AzoMOF). After ultraviolet (365 nm) irradiation, the isomerization of azobenzene groups in the AzoMOF was found to be able to modulate the spin relaxation of Sc3C2@C80 and also improve the single-molecule magnet behavior of DySc2N@C80. The photoisomerization of azobenzene side groups changes the host-guest interaction between metallofullerene and AzoMOF pores and endows them with the potential to modulate the magnetic properties with light. These findings offer an effective method to create smart molecular magnetic materials and also promote their applications in information recording, spintronics, and sensors.

An implanted paramagnetic metallofullerene probe within a metal-organic framework.

Paramagnetic endohedral metallofullerene can be used as a molecular probe because of its sensitive electron spin characters, one of which is to sense its surroundings. Metal-organic framework (MOF) materials have significant applications in selective adsorption owing to their porous structures. Herein, we report a Sc3C2@C80 spin probe implanted in MOF-177 to detect the unusual host-guest interaction between the guest molecules of metallofullerene and the host pores of the MOF. Paramagnetic Sc3C2@C80 molecules were incorporated into the pores of MOF-177 via absorption method, and there was strong π-π interaction between oleophilic metallofullerene and aromatic framework. The electron paramagnetic resonance (EPR) signals of Sc3C2@C80 in MOF-177 exhibit anisotropic properties caused by the restricted motion of implanted Sc3C2@C80. This unusual host-guest interaction between Sc3C2@C80 and MOF-177 is gradually strengthened with decreasing temperature as revealed by the EPR signals. In addition, the gas desorption from the MOF-177 pores under subatmospheric pressure can weaken the host-guest interaction and lead to slightly enhanced Sc3C2@C80 EPR signals. Furthermore, the changes in the host-guest interaction between Sc3C2@C80 and MOF-177 at different temperatures and pressures exhibit reversibility, as shown by cycling EPR measurements. These results will inspire material design and applications of fullerene and MOF complexes.