Multimodal channel cancer chemotherapy by 2D functional gadolinium metal–organic framework

2D nanomaterials generally exhibit enhanced physiochemical and biological functions in biomedical applications due to their high surface-to-volume ratio and surface charge. Conventional cancer chemotherapy based on nanomaterials has been hindered by their low drug loading and poor penetration in tumor tissue. To overcome these difficulties, novel materials systems are urgently needed. Hereby, the lanthanide-based porphyrin metal–organic framework (MOF) nanosheets (NSs) with promising cancer imaging/chemotherapy capacities are fabricated, which display superior performance in the drug loading and tumor tissue penetration. The biodegradable PPF-Gd NSs deliver an ultrahigh drug loading (>1500%) and demonstrate the stable and highly sensitive stimuli-responsive degradation/release for multimodal tumor imaging and cancer chemotherapy. Meanwhile, PPF-Gd NSs also exhibit excellent fluorescence and magnetic resonance imaging capability in vitro and in vivo. Compared to the traditional doxorubicin (DOX) chemotherapy, the in vivo results confirm the evident suppression of the tumor growth by the PPF-Gd/DOX drug delivery system with negligible side effects. This work further supports the potential of lanthanide-based MOF nanomaterials as biodegradable systems to promote the cancer theranostics technology development in the future.     

A highly alkaline-stable metal oxide@metal–organic framework composite for high-performance electrochemical energy storage

Most metal–organic frameworks (MOFs) hardly maintain their physical and chemical properties after exposure to alkaline aqueous solutions, thus precluding their use as potential electrode materials for electrochemical energy storage devices. Here, we present the design and synthesis of a highly alkaline-stable metal oxide@MOF composite, Co₃O₄ nanocube@Co-MOF (Co₃O₄@Co-MOF), via a controllable and facile one-pot hydrothermal method under highly alkaline conditions. The obtained composite possesses exceptional alkaline stability, retaining its original structure in 3.0 M KOH for at least 15 days. Benefitting from the exceptional alkaline stability, unique structure, and larger surface area, the Co₃O₄@Co-MOF composite shows a specific capacitance as high as 1020 F g⁻¹ at 0.5 A  g⁻¹ and a high cycling stability with only 3.3% decay after 5000 cycles at 5 A g⁻¹. The as-constructed solid-state flexible device exhibits a maximum energy density of 21.6 mWh cm⁻³.     

Encapsulating soluble active species into hollow crystalline porous capsules beyond integration of homogeneous and heterogeneous catalysis

Homogeneous molecular catalysts and heterogeneous catalysts possess complementary strengths, and are of great importance in laboratory/commercial procedures. While various porous hosts, such as polymers, carbons, silica, metal oxides and zeolites, have been used in an attempt to heterogenize homogeneous catalysts, realizing the integration of both functions at the expense of discounting their respective advantages, it remains a significant challenge to truly combine their intrinsic strengths in a single catalyst without compromise. Here, we describe a general template-assisted approach to incorporating soluble molecular catalysts into the hollow porous capsule, which prevents their leaching due to the absence of large intergranular space. In the resultant yolk (soluble)–shell (crystalline) capsules, the soluble yolks can perform their intrinsic activity in a mimetic homogeneous environment, and the crystalline porous shells endow the former with selective permeability, substrate enrichment, size-selective and heterogeneous cascade catalysis, beyond the integration of the respective advantages of homogeneous and heterogeneous catalysts.     

Hierarchically structured porous materials: synthesis strategies and applications in energy storage

To address the growing energy demands of sustainable development, it is crucial to develop new materials that can improve the efficiency of energy storage systems. Hierarchically structured porous materials have shown their great potential for energy storage applications owing to their large accessible space, high surface area, low density, excellent accommodation capability with volume and thermal variation, variable chemical compositions and well controlled and interconnected hierarchical porosity at different length scales. Porous hierarchy benefits electron and ion transport, and mass diffusion and exchange. The electrochemical behavior of hierarchically structured porous materials varies with different pore parameters. Understanding their relationship can lead to the defined and accurate design of highly efficient hierarchically structured porous materials to enhance further their energy storage performance. In this review, we take the characteristic parameters of the hierarchical pores as the survey object to summarize the recent progress on hierarchically structured porous materials for energy storage. This is the first of this kind exclusively to survey the performance of hierarchically structured porous materials from different porous characteristics. For those who are not familiar with hierarchically structured porous materials, a series of very significant synthesis strategies of hierarchically structured porous materials are firstly and briefly reviewed. This will be beneficial for those who want to quickly obtain useful reference information about the synthesis strategies of new hierarchically structured porous materials to improve their performance in energy storage. The effect of different organizational, structural and geometric parameters of porous hierarchy on their electrochemical behavior is then deeply discussed. We outline the existing problems and development challenges of hierarchically structured porous materials that need to be addressed in renewable energy applications. We hope that this review can stimulate strong intuition into the design and application of new hierarchically structured porous materials in energy storage and other fields.     

Encapsulating metal organic framework into hollow mesoporous carbon sphere as efficient oxygen bifunctional electrocatalyst

Applying metal organic frameworks (MOFs) in electrochemical systems is a currently emerging field owing to the rich metal nodes and highly specific surface area of MOFs. However, the problems for MOFs that need to be solved urgently are poor electrical conductivity and low ion transport. Here we present a facile in situ growth method for the rational synthesis of MOFs@hollow mesoporous carbon spheres (HMCS) yolk–shell-structured hybrid material for the first time. The size of the encapsulated Zeolitic Imidazolate Framework-67 (ZIF-67) is well controlled to 100 nm due to the spatial confinement effect of HMCS, and the electrical conductivity of ZIF-67 is also increased significantly. The ZIF@HMCS-25% hybrid material obtained exhibits a highly efficient oxygen reduction reaction activity with 0.823 V (vs. reversible hydrogen electrode) half-wave potential and an even higher kinetic current density (J_K = 13.8 mA cm⁻²) than commercial Pt/C. ZIF@HMCS-25% also displays excellent oxygen evolution reaction performance and the overpotential of ZIF@HMCS-25% at 10 mA cm⁻² is 407 mV. In addition, ZIF@HMCS-25% is further employed as an air electrode for a rechargeable Zn–air battery, exhibiting a high power density (120.2 mW cm⁻² at 171.4 mA cm⁻²) and long-term charge/discharge stability (80 h at 5 mA cm⁻²). This MOFs@HMCS yolk–shell design provides a versatile method for the application of MOFs as electrocatalysts directly.     

Hierarchically porous monoliths based on low-valence transition metal (Cu,Co, Mn) oxides: gelation and phase separation

Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after heat treatment in air.     

Lipid–oligonucleotide conjugates for bioapplications

Lipid–oligonucleotide conjugates (LONs) are powerful molecular-engineering materials for various applications ranging from biosensors to biomedicine. Their unique amphiphilic structures enable the self-assembly and the conveyance of information with high fidelity. In particular, LONs present remarkable potential in measuring cellular mechanical forces and monitoring cell behaviors. LONs are also essential sensing tools for intracellular imaging and have been employed in developing cell-surface-anchored DNA nanostructures for biomimetic-engineering studies. When incorporating therapeutic oligonucleotides or small-molecule drugs, LONs hold promise for targeted therapy. Moreover, LONs mediate the controllable assembly and fusion of vesicles based on DNA-strand displacements, contributing to nanoreactor construction and macromolecule delivery. In this review, we will summarize the general synthesis strategies of LONs, provide some characterization analysis and emphasize recent advances in bioanalytical and biomedical applications. We will also consider the relevant challenges and suggest future directions for building better functional LONs in nanotechnology and materials-science applications.     

Unprecedented strong and reversible atomic orbital hybridization enables a highly stable Li–S battery

The shuttle effect and excessive volume change of the sulfur cathode severely impede the industrial implementation of Li–S batteries. It is still highly challenging to find an efficient way to suppress the shuttle effect and volume expansion. Here, we report, for the first time, an innovative atomic orbital hybridization concept to construct the hierarchical hollow sandwiched sulfur nanospheres with double-polyaniline layers as the cathode material for large-scale high-performance Li–S batteries. This hierarchically 3D, cross-linked and stable sulfur–polyaniline backbone with interconnected disulfide bonds provides a new type and strong intrinsic chemical confinement of sulfur owing to the atomic orbital hybridization of Li 2s, S 3p, C 2p and N 2p. Crucially, such atomic orbital hybridization of sulfur sandwiched in the double sulfur–polyaniline network is highly reversible during the discharge/charge process and can very efficiently suppress the shuttle effect and volume expansion, contributing to a very high capacity of 1142 mAh g^–1 and an excellent stabilized capacity of 886 mAh g^–1 at 0.2 C after 500 cycles with a suppressed volume expansion and an unprecedented electrode integrity. This innovative atomic orbital hybridization concept can be extended to the preparation of other electrode materials to eliminate the shuttle effect and volume expansion in battery technologies. The present work also provides a commercially viable and up-scalable cathode material based on this strong and highly reversible atomic orbital hybridation for large-scale high-performance Li–S batteries.     

Redox mediators for high-performance lithium–oxygen batteries

Aprotic lithium–oxygen (Li–O₂) batteries are receiving intense research interest by virtue of their ultra-high theoretical specific energy. However, current Li–O₂ batteries are suffering from severe barriers, such as sluggish reaction kinetics and undesired parasitic reactions. Recently, molecular catalysts, i.e. redox mediators (RMs), have been explored to catalyse the oxygen electrochemistry in Li–O₂ batteries and are regarded as an advanced solution. To fully unlock the capability of Li–O₂ batteries, an in-depth understanding of the catalytic mechanisms of RMs is necessary. In this review, we summarize the working principles of RMs and their selection criteria, highlight the recent significant progress of RMs and discuss the critical scientific and technical challenges on the design of efficient RMs for next-generation Li–O₂ batteries.     

Unimodal productivity–biodiversity relationship along the gradient of multidimensional resources across Chinese grasslands

Resources can affect plant productivity and biodiversity simultaneously and thus are key drivers of their relationships in addition to plant–plant interactions. However, most previous studies only focused on a single resource while neglecting the nature of resource multidimensionality. Here we integrated four essential resources for plant growth into a single metric of resource diversity (RD) to investigate its effects on the productivity–biodiversity relationship (PBR) across Chinese grasslands. Results showed that habitats differing in RD have different PBRs—positive in low-resource habitats, but neutral in medium- and high-resource ones—while collectively, a weak positive PBR was observed. However, when excluding direct effects of RD on productivity and biodiversity, the PBR in high-resource habitats became negative, which leads to a unimodal instead of a positive PBR along the RD gradient. By integrating resource effects and changing plant–plant interactions into a unified framework with the RD gradient, our work contributes to uncovering underlying mechanisms for inconsistent PBRs at large scales.     

Decoupling engineering of formamidinium–cesium perovskites for efficient photovoltaics

Although pure formamidinium iodide perovskite (FAPbI₃) possesses an optimal gap for photovoltaics, their poor phase stability limits the long-term operational stability of the devices. A promising approach to enhance their phase stability is to incorporate cesium into FAPbI₃. However, state-of-the-art formamidinium–cesium (FA–Cs) iodide perovskites demonstrate much worse efficiency compared with FAPbI₃, limited by the different crystallization dynamics of formamidinium and cesium, which result in poor composition homogeneity and high trap densities. We develop a novel strategy of crystallization decoupling processes of formamidinium and cesium via a sequential cesium incorporation approach. As such, we obtain highly reproducible, highly efficient and stable solar cells based on FA_1–xCs_xPbI₃ (x = 0.05–0.16) films with uniform composition distribution in the nanoscale and low defect densities. We also revealed a new stabilization mechanism for Cs doping to stabilize FAPbI₃, i.e. the incorporation of Cs into FAPbI₃ significantly reduces the electron–phonon coupling strength to suppress ionic migration, thereby improving the stability of FA–Cs-based devices.     

Gene regulatory network stabilized by pervasive weak repressions: microRNA functions revealed by the May–Wigner theory

Food web and gene regulatory networks (GRNs) are large biological networks, both of which can be analyzed using the May–Wigner theory. According to the theory, networks as large as mammalian GRNs would require dedicated gene products for stabilization. We propose that microRNAs (miRNAs) are those products. More than 30% of genes are repressed by miRNAs, but most repressions are too weak to have a phenotypic consequence. The theory shows that (i) weak repressions cumulatively enhance the stability of GRNs, and (ii) broad and weak repressions confer greater stability than a few strong ones. Hence, the diffuse actions of miRNAs in mammalian cells appear to function mainly in stabilizing GRNs. The postulated link between mRNA repression and GRN stability can be seen in a different light in yeast, which do not have miRNAs. Yeast cells rely on non-specific RNA nucleases to strongly degrade mRNAs for GRN stability. The strategy is suited to GRNs of small and rapidly dividing yeast cells, but not the larger mammalian cells. In conclusion, the May–Wigner theory, supplanting the analysis of small motifs, provides a mathematical solution to GRN stability, thus linking miRNAs explicitly to ‘developmental canalization’.     

Iron in the NEEM ice core relative to Asian loess records over the last glacial–interglacial cycle

Mineral dust can indirectly affect the climate by supplying bioavailable iron (Fe) to the ocean. Here, we present the records of dissolved Fe (DFe) and total Fe (TDFe) in North Greenland Eemian Ice Drilling (NEEM) ice core over the past 110 kyr BP. The Fe records are significantly negatively correlated with the carbon-dioxide (CO₂) concentrations during cold periods. The results suggest that the changes in Fe fluxes over the past 110 kyr BP in the NEEM ice core are consistent with those in Chinese loess records because the mineral-dust distribution is controlled by the East Asian deserts. Furthermore, the variations in the dust input on a global scale are most likely driven by changes in solar radiation during the last glacial–interglacial cycle in response to Earth''s orbital cycles. In the last glacial–interglacial cycle, the DFe/TDFe ratios were higher during the warm periods (following the post-Industrial Revolution and during the Holocene and last interglacial period) than during the main cold period (i.e. the last glacial maximum (LGM)), indicating that the aeolian input of iron and the iron fertilization effect on the oceans have a non-linear relationship during different periods. Although the burning of biomass aerosols has released large amounts of DFe since the Industrial Revolution, no significant responses are observed in the DFe and TDFe variations during this period, indicating that severe anthropogenic contamination has no significant effect on the DFe (TDFe) release in the NEEM ice core.     

Direct transformation of dinitrogen: synthesis of N-containing organic compounds via N−C bond formation

N-containing organic compounds are of vital importance to lives. Practical synthesis of valuable N-containing organic compounds directly from dinitrogen (N₂), not through ammonia (NH₃), is a holy-grail in chemistry and chemical industry. An essential step for this transformation is the functionalization of the activated N₂ units/ligands to generate N−C bonds. Pioneering works of transition metal-mediated direct conversion of N₂ into organic compounds via N−C bond formation at metal-dinitrogen [N₂-M] complexes have generated diversified coordination modes and laid the foundation of understanding for the N−C bond formation mechanism. This review summarizes those major achievements and is organized by the coordination modes of the [N₂-M] complexes (end-on, side-on, end-on-side-on, etc.) that are involved in the N−C bond formation steps, and each part is arranged in terms of reaction types (N-alkylation, N-acylation, cycloaddition, insertion, etc.) between [N₂-M] complexes and carbon-based substrates. Additionally, earlier works on one-pot synthesis of organic compounds from N₂ via ill-defined intermediates are also briefed. Although almost all of the syntheses of N-containing organic compounds via direct transformation of N₂ so far in the literature are realized in homogeneous stoichiometric thermochemical reaction systems and are discussed here in detail, the sporadically reported syntheses involving photochemical, electrochemical, heterogeneous thermo-catalytic reactions, if any, are also mentioned. This review aims to provide readers with an in-depth understanding of the state-of-the-art and perspectives of future research particularly in direct catalytic and efficient conversion of N₂ into N-containing organic compounds under mild conditions, and to stimulate more research efforts to tackle this long-standing and grand scientific challenge.     

基于Logistic-ISM模型的农户有机肥施用行为影响因素及层次结构分解

有机肥施用对中国农业绿色、可持续发展具有重要作用,但目前在农业生产上,尤其是稻、麦等大田作物生产上施用率却较低。农户作为农业生产的主体,拥有肥料施用的决策权,明确稻麦轮作区农户有机肥施用行为及关键影响因素对促进有机肥在大田作物的施用有重要意义。本文基于江苏省稻麦轮作区4县（区）392户农户调查数据,采用Logistic模型与解释结构模型（ISM）,分析了农户在稻麦轮作农田施用有机肥的影响因素及其层次结构。结果表明：农户的受教育程度、对有机肥的了解程度、对长期大量低效施用化肥造成环境污染的认识、购买肥料时考虑对土壤无害、饲养家禽及农业部门针对农业施肥技术进行指导等因素对农户有机肥施用行为有正向影响,购买肥料时考虑价格和省工对农户有机肥施用行为有负向影响。在此基础上,对8个因素进行深层分析,形成了“一路径,三驱动”的层次结构,并提出了相应的有机肥推广政策建议。     

Efficient rare earth cerium(III) complex with nanosecond d−f emission for blue organic light-emitting diodes

In the field of RGB diodes, development of a blue organic light-emitting diode (OLED) is a challenge because of the lack of an emitter which simultaneously has a short excited state lifetime and a high theoretical external quantum efficiency (EQE). We demonstrate herein a blue emissive rare earth cerium(III) complex Ce-2 showing a high photoluminescence quantum yield of 95% and a short excited state lifetime of 52.0 ns in doped film, which is considerably faster than that achieved in typical efficient phosphorescence or thermally activated delayed fluorescence emitters (typical lifetimes >1 μs). The corresponding OLED shows a maximum EQE up to 20.8% and a still high EQE of 18.2% at 1000 cd m⁻², as well as an operation lifetime 70 times longer than that of a classic phosphorescence OLED. The excellent performance indicates that cerium(III) complex could be a candidate for efficient and stable blue OLEDs because of its spin- and parity-allowed d−f transition from the Ce³⁺ ion.     

A critical review of mineral–microbe interaction and co-evolution: mechanisms and applications

Mineral–microbe interactions play important roles in environmental change, biogeochemical cycling of elements and formation of ore deposits. Minerals provide both beneficial (physical and chemical protection, nutrients, and energy) and detrimental (toxic substances and oxidative pressure) effects to microbes, resulting in mineral-specific microbial colonization. Microbes impact dissolution, transformation and precipitation of minerals through their activity, resulting in either genetically controlled or metabolism-induced biomineralization. Through these interactions, minerals and microbes co-evolve through Earth history. Mineral–microbe interactions typically occur at microscopic scale but the effect is often manifested at global scale. Despite advances achieved through decades of research, major questions remain. Four areas are identified for future research: integrating mineral and microbial ecology, establishing mineral biosignatures, linking laboratory mechanistic investigation to field observation, and manipulating mineral–microbe interactions for the benefit of humankind.     

Red blood cell membrane-camouflaged nanoparticles loaded with AIEgen and Poly(I : C) for enhanced tumoral photodynamic-immunotherapy

Red blood cell (RBC)-mimicking nanoparticles (NPs) offer a promising platform for drug delivery because of their prolonged circulation time, reduced immunogenicity and specific targeting ability. Herein, we report the design and preparation of RBC membrane-bound NPs (M@AP), for tumoral photodynamic-immunotherapy. The M@AP is formed by self-assembly of the positively charged aggregation-induced emission luminogen (AIEgen) (named P2-PPh3) and the negatively charged polyinosinic : polycytidylic acid (Poly(I : C)), followed by RBC membrane encapsulation. P2-PPh3 is an AIE-active conjugated polyelectrolyte with additional photosensitizing ability for photodynamic therapy (PDT), while Poly(I : C) serves as an immune-stimulant to stimulate both tumor and immune cells to activate immunity, and thus reduces tumor cell viability. When applied in tumor-bearing mice, the M@AP NPs are enriched in both the tumor region as a result of an enhanced permeability and retention (EPR) effect, and the spleen because of the homing effect of the RBC-mimicking shell. Upon light irradiation, P2-PPh3 promotes strong ROS generation in tumor cells, inducing the release of tumor antigens (TA). The anti-tumor immunity is further enhanced by the presence of Poly(I : C) in M@AP. Thus, this strategy combines the PDT properties of the AIE-active polyelectrolyte and immunotherapy properties of Poly(I : C) to achieve synergistic activation of the immune system for anti-tumor activity, providing a novel strategy for tumor treatment.