A TICT-AIE activated dual-channel fluorescence-on probe to reveal the dynamics mechanosensing of lipid droplets during ferroptosis.

Mechanical forces play a crucial role in cellular processes, including ferroptosis, a form of regulated cell death associated with various diseases. However, the mechanical aspects of organelle lipid droplets (LDs) during ferroptosis are poorly understood. In this study, we designed and synthesized a fluorescent probe, TPE-V1, to enable real-time monitoring of LDs' viscosity using a dual-channel fluorescence-on model (red channel at 617 nm and NIR channel at 710 nm). The fluorescent imaging of using TPE-V1 was achieved due to the integrated mechanisms of the twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE). Through dual-emission channel fluorescence imaging, we observed the enhanced mechanical energy of LDs triggering cellular mechanosensing, including ferroptosis and cell deformation. Theoretical calculations confirmed the probe's behavior, showing that high-viscosity media prevented the rotation processes and restored fluorescence quenching in low viscosity. These findings suggest that our TICT-TPE design strategy provides a practical approach to study LDs' mechanical properties during ferroptosis. This development enhances our understanding of the interplay between mechanical forces and LDs, contributing to the knowledge of ferroptotic cell death and potential therapeutic interventions targeting dysregulated cell death processes.

Multifunctional fluorescent probe for simultaneous revealing Cys and ONOO- dynamic correlation in the ferroptosis.

Ferroptosis is a type of lipid peroxidation-induced apoptosis brought on by imbalances in iron metabolism and redox. It involves both the thiol-associated anti-ferroptosis pathway and the excessive buildup of reactive oxygen species (ROS), which stimulates the ferroptosis pathway. Determining the precise control mechanism of ferroptosis requires examining the dynamic connection between reactive sulfur species (RSS) and ROS. Cysteine (Cys) and peroxynitrite (ONOO-) are highly active redox species in organisms and play dynamic roles in the ferroptosis process. In this study, a coumarin dye was conjugated with specific response sites for Cys and ONOO-, enabling the simultaneous detection of Cys and ONOO- through the green and red fluorescence channels, respectively (λem = 498 nm for Cys and λem = 565 nm for ONOO-). Using the probe LXB, we monitored the changes in Cys and ONOO- levels in the ferroptosis pathway induced by erastin. The results demonstrate a significant generation of ONOO- and a noticeable decrease in intracellular Cys levels at the beginning upon erastin treatment and finally maintains a relatively low level. This study presents the first probe to investigate the intracellular redox modulation and control between Cys and ONOO- during ferroptosis, providing valuable insights into the potential mutual correlation between Cys and ONOO- in this process.

Regulating Au coverage for the direct oxidation of methane to methanol.

The direct oxidation of methane to methanol under mild conditions is challenging owing to its inadequate activity and low selectivity. A key objective is improving the selective oxidation of the first carbon-hydrogen bond of methane, while inhibiting the oxidation of the remaining carbon-hydrogen bonds to ensure high yield and selectivity of methanol. Here we design ultrathin PdxAuy nanosheets and revealed a volcano-type relationship between the binding strength of hydroxyl radical on the catalyst surface and catalytic performance using experimental and density functional theory results. Our investigations indicate a trade-off relationship between the reaction-triggering and reaction-conversion steps in the reaction process. The optimized Pd3Au1 nanosheets exhibits a methanol production rate of 147.8 millimoles per gram of Pd per hour, with a selectivity of 98% at 70 °C, representing one of the most efficient catalysts for the direct oxidation of methane to methanol.

Multimetallic Single-Atom Catalysts for Bifunctional Oxygen Electrocatalysis.

Multimetallic alloys have demonstrated promising performance for the application of metal-air batteries, while it remains a challenge to design multimetallic single-atom catalysts (MM-SACs). Herein, metal-C3N4 and nitrogen-doped carbon are employed as cornerstones to synthesize MM-SACs by a general two-step method, and the inherent features of atomic dispersion and the strong electronic reciprocity between the multimetallic sites have been verified. The trimetallic FeCoZn-SACs and quatermetallic FeCoCuZn-SACs are both found to deliver superior oxygen evolution reaction and oxygen reduction reaction activity, respectively, as well as outstanding bifunctional durability. Density functional theory calculations elucidate the crucial contribution of Co sites of FeCoCuZn-SACs to the efficient catalysis of both the ORR and the OER. More importantly, Zn-air batteries with FeCoCuZn-SACs as cathodic catalysts exhibit a high power density (252 mW cm-2), high specific capacity (817 mAh gZn-1), and considerable stability (over 225 h) for charging-discharging processes. This work provides a visual perspective for the advantages of MM-SACs toward oxygen electrocatalysis.

A Calcination-Free Sol-Gel Method to Prepare TiO2 -Based Hybrid Semiconductors for Enhanced Visible Light-Driven Hydrogen Production.

Invited for this month's cover are the collaborating groups of Dr. Jianwei Li at the University of Turku and Prof. Chunman Jia, Kang Yang and Dan Wei at Hainan University. The cover image compares the structure of calcined (left) and non-calcined (right) rutile TiO2 doped with a molecule NA. The calcination process enlarges the pores in TiO2 , reducing its surface area and hydrogen production efficiency under visible light. The "sad face" symbolizes the damaged pore structure. Conversely, doping TiO2 with NA without high-temperature calcination forms a covalent bond, resulting in smaller pores, larger surface area, and improved hydrogen production efficiency. The "smiley face" represents the structurally intact TiO2 hybrid material. More information can be found in the Research Article by Jianwei Li, Chunman Jia, and co-workers.

Visible light-driven highly-efficient hydrogen production by a naphthalene imide derivative-sensitized TiO2 photocatalyst.

Sensitizing titanium dioxide (TiO2) with dye molecules offers a cost-effective and environmentally friendly strategy for creating powerful photocatalysts for hydrogen production by reducing the band gap and enhancing sunlight absorption. Despite the challenges of identifying a stable dye with high light harvesting efficiency and effective charge recombination, we present a 1,8-naphthalimide derivative-sensitized TiO2 that achieves ultra-efficient photocatalytic hydrogen production (10.615 mmol g-1 h-1) and maintains activity after 30 hours of cycling. Our research offers valuable insights for designing optimized organic dye-sensitized photocatalysts, advancing clean and sustainable energy solutions.

A Calcination-Free Sol-Gel Method to Prepare TiO2 -Based Hybrid Semiconductors for Enhanced Visible Light-Driven Hydrogen Production.

In recent years, the sol-gel method has been extensively utilized to develop efficient and stable organic semiconductor composite titanium dioxide (TiO2 ) photocatalysts. However, the high-temperature calcination requirements of this method consume energy during preparation and degrade encapsulated organic semiconductor molecules, resulting in decreased photocatalytic hydrogen production efficiency. In this study, we found that by selecting an appropriate organic semiconductor molecule, 1,4-naphthalene dicarboxylic acid (NA), high-temperature calcination can be avoided in the sol-gel process, yielding an organic-inorganic hybrid material with stable and effective photocatalytic properties. The uncalcined material displayed a hydrogen production rate of 2920±15 µmol g-1 h-1 , which was approximately twice the maximum production rate observed in the calcined material. Likewise, the specific surface area of the uncalcined material, at 252.84 m2 g-1 , was significantly larger compared to the calcined material. Comprehensive analyses confirmed successful NA and TiO2 doping, while UV-vis and Mott-Schottky tests revealed a reduced energy bandgap (2.1 eV) and expanded light absorption range. Furthermore, the material maintained robust photocatalytic activity after a 40-hour cycle test. Our findings demonstrate that by using NA doping without calcination, excellent hydrogen production performance can be achieved, offering a novel approach for environmentally friendly and energy-saving production of organic semiconductor composite TiO2 materials.

Ultrathin Pd3 Pt1 Rh0.1 Nanorings with Strong C-C Bond Breaking Ability for the Ethanol Oxidation Reaction.

Ethanol as a fuel for direct ethanol fuel cells (DEFCs) has the advantages of being highly energetic, environmentally friendly, and low-cost, while the slow anodic ethanol oxidation reaction (EOR), intermediate poisoning effect, and incomplete oxidation of ethanol became obstacles to the development of DEFCs. Herein, a 2D ternary cyclic Pd3 Pt1 Rh0.1 nanorings (NRs) catalyst with efficient EOR performance is prepared via a facile one-pot solvothermal approach, and systematic studies are carried out to reveal the mechanisms of the enhanced performance and C-C bond selectivity. In particular, the optimized catalyst exhibits impressive mass activity, stability, toxicity resistance, and C-C bond cleavage ability. It's proposed that the considerable performance is attributed to the unique hollow structure, providing abundant active sites. The high toxicity resistance is not only attributed to the electronic modulation of the catalyst material by Rh atoms, but also depends on the excellent water activation properties of Rh, which contribute to the removal of intermediates, such as CO. In addition, the density functional theory calculations showed that the introduction of Rh significantly enhances the C-C bond cleavage ability of the catalyst, further improving the EOR activity.

Small-Molecule-based Supramolecular Plastics Mediated by Liquid-Liquid Phase Separation.

Plastics are one of the most widely used polymeric materials. However, they are often undegradable and non-recyclable due to the very stable covalent bonds of macromolecules, causing environmental pollution and health problems. Here, we report that liquid-liquid phase separation (LLPS) could drive the formation of robust, stable, and sustainable plastics using small molecules. The LLPS process could sequester and concentrate solutes, strengthen the non-covalent association between molecules and produce a bulk material whose property was highly related to the encapsulated water amounts. It was a robust plastic with a remarkable Young's modulus of 139.5 MPa when the water content was low while became adhesive and could instantly self-heal with more absorbed water. Finally, responsiveness enabled the material to be highly recyclable. This work allowed us to understand the LLPS at the molecular level and demonstrated that LLPS is a promising approach to exploring eco-friendly supramolecular plastics that are potential substitutes for conventional polymers.

Enhanced Photocatalytic Hydrogen Production Activity by Constructing a Robust Organic-Inorganic Hybrid Material Based Fulvalene and TiO2.

A novel redox-active organic-inorganic hybrid material (denoted as H4TTFTB-TiO2) based on tetrathiafulvalene derivatives and titanium dioxide with a micro/mesoporous nanomaterial structure has been synthesized via a facile sol-gel method. In this study, tetrathiafulvalene-3,4,5,6-tetrakis(4-benzoic acid) (H4TTFTB) is an ideal electron-rich organic material and has been introduced into TiO2 for promoting photocatalytic H2 production under visible light irradiation. Notably, the optimized composites demonstrate remarkably enhanced photocatalytic H2 evolution performance with a maximum H2 evolution rate of 1452 µmol g-1 h-1, which is much higher than the prototypical counterparts, the common dye-sensitized sample (denoted as H4TTFTB-5.0/TiO2) (390.8 µmol g-1 h-1) and pure TiO2 (18.87 µmol g-1 h-1). Moreover, the composites perform with excellent stability even after being used for seven time cycles. A series of characterizations of the morphological structure, the photoelectric physics performance and the photocatalytic activity of the hybrid reveal that the donor-acceptor structural H4TTFTB and TiO2 have been combined robustly by covalent titanium ester during the synthesis process, which improves the stability of the hybrid nanomaterials, extends visible-light adsorption range and stimulates the separation of photogenerated charges. This work provides new insight for regulating precisely the structure of the fulvalene-based composite at the molecule level and enhances our in-depth fundamental understanding of the photocatalytic mechanism.

A curcumin-based AIEE-active fluorescent probe for Cu2+ detection in aqueous solution.

Curcuminoids have been extensively investigated as metal ion probes, but the intrinsic aggregation-caused-quenching (ACQ) characteristic of curcumin would hinder their applications in aqueous solution. Fortunately, tetraphenylethylene (TPE) could endow the compounds with aggregation-induced emission (AIE)/aggregation-induced enhanced emission (AIEE) characteristics to eliminate the ACQ effect. According to this strategy, a series of TPE-modified curcumin derivatives L1-4 were prepared and studied for their AIEE properties. Among the four TPE-curcumin analogues, only L1 particles have been successfully used as an on-off fluorescence probe for detecting Cu2+ in aqueous solution. The fluorescence titration experiment determined its detection limit of 1.49 × 10-7 mol L-1, and the binding ratio between L1 and Cu2+ was estimated as 2 : 1, which was in agreement with the results of high resolution mass spectrum and Job's plot. In addition, the binding constant was evaluated as 6.77 × 102 M-1 using a Benesi-Hildebrand plot. Finally, the obtained L1-based indicator paper showed significant fluorescence response to Cu2+ aqueous solution. This TPE-modified strategy improves the detection capability of curcumin probe in aqueous solution and provides a feasible way to obtain other probes with ACQ characteristics.

General Method for Synthesizing Effective and Durable Electrocatalysts Derived from Cellulose for Microbial Fuel Cells.

Microbial fuel cells (MFCs) can be capable of both wastewater treatment and electricity generation, which necessarily depends on the increasing cathodic performances and stability at low cost to realize industrialization. Herein, cellulose, a commercially available and sustainable material, was oxidized as a carbon precursor to produce the oxygen species synergizing the nitrogen-doped carbon (CON-900) catalyst by a facile in situ nitrogen doping method. The incorporation of nitrogen and oxygen with a high content creates more active centers. Meanwhile, the hierarchical porosity of CON-900 contributes to a high specific surface area (652 m2 g-1) and the exposure of accessible active sites. As expected, CON-900 exhibits considerable activity for the oxygen reduction reaction, excellent operating stability, and high poisoning resistance. In addition, the MFC fabricated with CON-900 as a cathode catalyst demonstrates a maximum power density of 1014 ± 23 mW m-2, which is comparable with that of the Pt/C cathode (1062 ± 14 mW m-2). This work offers a facile and versatile strategy for various biomass materials to develop low-cost and high-efficiency carbon-based catalysts for MFCs and beyond.

Progress in the development of heteroatom-doped nickel phosphates for electrocatalytic water splitting.

Hydrogen energy is expected to replace fossil fuels as a mainstream energy source in the future. Currently, hydrogen production via water electrolysis yields high hydrogen purity with easy operation and without producing polluting side products. Presently, platinum group metals and their oxides are the most effective catalysts for water splitting; however, their low abundance and high cost hinder large-scale hydrogen production, especially in alkaline and neutral media. Therefore, the development of high-efficiency, durable, and low-cost electrocatalysts is crucial to improving the overpotential and lowering the electrical energy consumption. As a solution, Ni2P has attracted particular attention, owing to its desirable electrical conductivity, high corrosion resistance, and remarkable catalytic activity for overall water splitting, and thus, is a promising substitute for platinum-group catalysts. However, the catalytic performance and durability of raw Ni2P are still inferior to those of noble metal-based catalysts. Heteroatom doping is a universal strategy for enhancing the performance of Ni2P for water electrolysis over a wide pH range, because the electronic structure and crystal structure of the catalyst can be modulated, and the adsorption energy of the reaction intermediates can be adjusted via doping, thus optimizing the reaction performance. In this review, first, the reaction mechanisms of water electrolysis, including the cathodic hydrogen evolution reaction and anodic oxygen evolution reaction, are briefly introduced. Then, progress into heteroatom-doped nickel phosphide research in recent years is assessed, and a discussion of each representative work is given. Finally, the opportunities and challenges for developing advanced Ni2P based electrocatalysts are proposed and discussed.

Synthesis and Design of a Highly Stable Platinum Nickel Electrocatalyst for the Oxygen Reduction Reaction.

Exploring effective, stable, and affordable oxygen reduction reaction (ORR) catalysts is very significant for the practical application of proton-exchange membrane fuel cells. In this work, a facile and expandable method is developed to prepare ultrathin PtNi nanowires (NWs) with various Pt/Ni contents, and the ORR performance of the synthesized samples is thoroughly investigated. Pt3.2Ni NWs show the best ORR performance among the studied samples and, notably, exhibit much better ORR activity and stability than those of the Pt/C catalyst even after a 300,000-continuous cycling test. This work confirms that the initial Pt/Ni ratio plays a critical role in the ORR activity and stability of PtNi NWs, and the structure of the PtNi NWs can be well retained after the durability test. Additionally, the structure and performance of Pt3.2Ni NWs are investigated in detail during various cycles, and the performance decay is attributed to the dealloying of Ni and the corrosion of the one-dimensional structure after a prolonged durability test. This work provides a desirable method for rationally synthesizing a highly efficient ORR electrocatalyst with remarkable stability.

Engineering Ruthenium-Based Electrocatalysts for Effective Hydrogen Evolution Reaction.

The investigation of highly effective, durable, and cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is a prerequisite for the upcoming hydrogen energy society. To establish a new hydrogen energy system and gradually replace the traditional fossil-based energy, electrochemical water-splitting is considered the most promising, environmentally friendly, and efficient way to produce pure hydrogen. Compared with the commonly used platinum (Pt)-based catalysts, ruthenium (Ru) is expected to be a good alternative because of its similar hydrogen bonding energy, lower water decomposition barrier, and considerably lower price. Analyzing and revealing the HER mechanisms, as well as identifying a rational design of Ru-based HER catalysts with desirable activity and stability is indispensable. In this review, the research progress on HER electrocatalysts and the relevant describing parameters for HER performance are briefly introduced. Moreover, four major strategies to improve the performance of Ru-based electrocatalysts, including electronic effect modulation, support engineering, structure design, and maximum utilization (single atom) are discussed. Finally, the challenges, solutions and prospects are highlighted to prompt the practical applications of Ru-based electrocatalysts for HER.

Self-Synthesizing Nanorods from Dynamic Combinatorial Libraries against Drug Resistant Cancer.

Molecular self-assembly has been widely used to develop nanocarriers for drug delivery. However, most of them have unsatisfactory drug loading capacity (DLC) and the dilemma between stimuli-responsiveness and stability, stagnating their translational process. Herein, we overcame these drawbacks using dynamic combinatorial chemistry. A carrier molecule was spontaneously and quantitatively synthesized, aided by co-self-assembly with a template molecule and an anti-cancer drug doxorubicin (DOX) from a dynamic combinatorial library that was operated by disulfide exchange under thermodynamic control. The highly selective synthesis guaranteed a stable yet pH- and redox- responsive nanocarrier with a maximized DLC of 40.1 % and an enhanced drug potency to fight DOX resistance in vitro and in vivo. Our findings suggested that harnessing the interplay between synthesis and self-assembly in complex chemical systems could yield functional nanomaterials for advanced applications.

Potassium Acetate-Catalyzed Double Decarboxylative Transannulation To Access Highly Functionalized Pyrroles.

The development of new synthetic strategies for the efficient construction of versatile pyrrole pharmacores, especially in an operationally simple and environmentally benign fashion, still remains a momentous yet challenging goal. Here, we report a KOAc-catalyzed double decarboxylative transannulation between readily accessible oxazolones and isoxazolidinediones. This transformation represents a new way for skeletal remodeling by utilizing CO2 moiety as traceless activating and directing groups in both reaction partners. The synthetic value is evidenced by the rapid preparation of a broad spectrum of highly functionalized 3-carbamoyl-4-aryl pyrroles in good to excellent yields with exclusive regio-control, including the important Atorvastatin core.

Gadolinium-doped carbon quantum dots loaded magnetite nanoparticles as a bimodal nanoprobe for both fluorescence and magnetic resonance imaging.

Nowadays, it is highly desired to develop dual-modal fluorescence and magnetic resonance imaging (FI/MRI) probes in medical imaging because it unites the respective advantages of each imaging modality: high sensitivity of FI and superior spatial resolution of MRI. In this study, a facile strategy to fabricate a new bimodal imaging nanoprobe (Gd-CQDs@N-Fe3O4) was reported by integrating the fluorescence ability of carbon quantum dots (CQDs) and T1 and T2 contrast-enhancing functionality of Gd(III) ions and Fe3O4 nanoparticles into a single hybrid nanostructure. The hybrid composites were investigated by FT-IR, XRD, TEM, XPS, VSM, and so on, which confirmed that Gd-CQDs@N-Fe3O4 nanoparticles were successfully obtained and exhibited superparamagnetic property at room temperature. The derived nanoprobes presented an excitation wavelength-independent emission behavior. In addition, r1 and r2 relaxivities of the synthesized imaging nanoprobes were measured to be 5.16 and 115.6 mM-1 s-1, which nominated Gd-CQDs@N-Fe3O4 nanocomposites as a suitable T1-T2 contrast agent. The Gd-CQDs@N-Fe3O4 nanoparticles combining two synergetic imaging modalities showed great potential in FI/MRI dual-modal imaging for a more complementary and accurate detection.

A NIR fluorescent probe for the detection of fluoride ions and its application in in vivo bioimaging.

A novel near-infrared (NIR) fluorescent probe for the detection of fluoride ions has been developed, which is based on the F-triggered cleavage reaction of the Si-O bond. This probe exhibits excellent selectivity and sensitivity towards fluoride ions. The results of bioimaging experiments with HepG2 cells and mice show that the fluoride probe is available for visualizing exogenous fluoride ions in vitro and in vivo.

A novel fluorophore based on the coupling of AIE and ESIPT mechanisms and its application in biothiol imaging.

A novel fluorophore TPE-HBT was designed based on the intersection of tetraphenylethene (TPE) and 2-(2'-hydroxyphenyl)benzothiazole (HBT). Owing to the synergistic effect of aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) mechanisms, this fluorophore exhibits excellent performance with a high solid-state fluorescence quantum yield (ΦF = 0.97) and a large Stokes shift (>200 nm). Moreover, its simple modification with the 2,4-dinitrobenzenesulfonyl group makes it suitable for biothiol imaging.