A review of functions and mechanisms of clay soil conditioners and catalysts in thermal remediation compared to emerging photo-thermal catalysis

High temperatures and providing sufficient time for the thermal desorption of persistent organic pollutants (POPs) from contaminated clay soils can lead to intensive energy consumption. Therefore, this article provides a critical review of the potential additives which can improve soil texture and increase the volatility of POPs, and then discusses their enhanced mechanisms for contributing to a green economy. Ca-based additives have been used to reduce plasticity of bentonite clay, absorb water and replenish system heat. In contrast, non-Ca-based additives have been used to decrease the plasticity of kaolin clay. The soil structure and soil plasticity can be changed through cation exchange and flocculation processes. The transition metal oxides and alkali metal oxides can be applied to catalyze and oxidize polycyclic aromatic hydrocarbons, petroleum and emerging contaminants. In this system, reactive oxygen species (•O2- and •OH) are generated from thermal excitation without strong chemical oxidants. Moreover, multiple active ingredients in recycled solid wastes can be controlled to reduce soil plasticity and enhance thermal catalysis. Alternatively, the alkali, nano zero-valent iron and nano-TiN can catalyze hydrodechlorination of POPs under reductive conditions. Especially, photo and photo-thermal catalysis are discussed to accelerate replacement of fossil fuels by renewable energy in thermal remediation.

The autophagy-lysosome pathway: a potential target in the chemical and gene therapeutic strategies for Parkinson's disease

Parkinson's disease is a common neurodegenerative disease with movement disorders associated with the intracytoplasmic deposition of aggregate proteins such as α-synuclein in neurons. As one of the major intracellular degradation pathways, the autophagy-lysosome pathway plays an important role in eliminating these proteins. Accumulating evidence has shown that upregulation of the autophagy-lysosome pathway may contribute to the clearance of α-synuclein aggregates and protect against degeneration of dopaminergic neurons in Parkinson's disease. Moreover, multiple genes associated with the pathogenesis of Parkinson's disease are intimately linked to alterations in the autophagy-lysosome pathway. Thus, this pathway appears to be a promising therapeutic target for treatment of Parkinson's disease. In this review, we briefly introduce the machinery of autophagy. Then, we provide a description of the effects of Parkinson's disease-related genes on the autophagy-lysosome pathway. Finally, we highlight the potential chemical and genetic therapeutic strategies targeting the autophagy-lysosome pathway and their applications in Parkinson's disease.

Investigating the mechanism of chloroplast singlet oxygen signaling in the Arabidopsis thaliana accelerated cell death 2 mutant

As sessile organisms, plants have evolved complex signaling mechanisms to sense stress and acclimate. This includes the use of reactive oxygen species (ROS) generated during dysfunctional photosynthesis to initiate signaling. One such ROS, singlet oxygen (1O2), can trigger retrograde signaling, chloroplast degradation, and programmed cell death. However, the signaling mechanisms are largely unknown. Several proteins (e.g. PUB4, OXI1, EX1) are proposed to play signaling roles across three Arabidopsis thaliana mutants that conditionally accumulate chloroplast 1O2 (fluorescent in blue light (flu), chlorina 1 (ch1), and plastid ferrochelatase 2 (fc2)). We previously demonstrated that these mutants reveal at least two chloroplast 1O2 signaling pathways (represented by flu and fc2/ch1). Here, we test if the 1O2-accumulating lesion mimic mutant, accelerated cell death 2 (acd2), also utilizes these pathways. The pub4-6 allele delayed lesion formation in acd2 and restored photosynthetic efficiency and biomass. Conversely, an oxi1 mutation had no measurable effect on these phenotypes. acd2 mutants were not sensitive to excess light (EL) stress, yet pub4-6 and oxi1 both conferred EL tolerance within the acd2 background, suggesting that EL-induced 1O2 signaling pathways are independent from spontaneous lesion formation. Thus, 1O2 signaling in acd2 may represent a third (partially overlapping) pathway to control cellular degradation.

Advanced applications of smart electrospun nanofibers in cancer therapy: With insight into material capabilities and electrospinning parameters

Cancer remains a major global health challenge, and despite available treatments, its prognosis remains poor. Recently, researchers have turned their attention to intelligent nanofibers for cancer drug delivery. These nanofibers exhibit remarkable capabilities in targeted and controlled drug release. Their inherent characteristics, such as a high surface area-to-volume ratio, make them attractive candidates for drug delivery applications. Smart nanofibers can release drugs in response to specific stimuli, including pH, temperature, magnetic fields, and light. This unique feature not only reduces side effects but also enhances the overall efficiency of drug delivery systems. Electrospinning, a widely used method, allows the precision fabrication of smart nanofibers. Its advantages include high efficiency, user-friendliness, and the ability to control various manufacturing parameters. In this review, we explore the latest developments in producing smart electrospun nanofibers for cancer treatment. Additionally, we discuss the materials used in manufacturing these nanofibers and the critical parameters involved in the electrospinning process.

Imbalanced and Unchecked: The Role of Metal Dyshomeostasis in Driving COPD Progression

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterized by persistent inflammation and oxidative stress, which ultimately leads to progressive restriction of airflow. Extensive research findings have cogently suggested that the dysregulation of essential transition metal ions, notably iron, copper, and zinc, stands as a critical nexus in the perpetuation of inflammatory processes and oxidative damage within the lungs of COPD patients. Unraveling the intricate interplay between metal homeostasis, oxidative stress, and inflammatory signaling is of paramount importance in unraveling the intricacies of COPD pathogenesis. This comprehensive review aims to examine the current literature on the sources, regulation, and mechanisms by which metal dyshomeostasis contributes to COPD progression. We specifically focus on iron, copper, and zinc, given their well-characterized roles in orchestrating cytokine production, immune cell function, antioxidant depletion, and matrix remodeling. Despite the limited number of clinical trials investigating metal modulation in COPD, the advent of emerging methodologies tailored to monitor metal fluxes and gauge responses to chelation and supplementation hold great promise in unlocking the potential of metal-based interventions. We conclude that targeted restoration of metal homeostasis represents a promising frontier for ameliorating pathological processes driving COPD progression.

Disordered mesoporous silica particles: an emerging platform to deliver proteins to the lungs

Pulmonary delivery and formulation of biologics are among the more complex and growing scientific topics in drug delivery. We herein developed a dry powder formulation using disordered mesoporous silica particles (MSP) as the sole excipient and lysozyme, the most abundant antimicrobial proteins in the airways, as model protein. The MSP had the optimal size for lung deposition (2.43 ± 0.13 µm). A maximum lysozyme loading capacity (0.35 mg/mg) was achieved in 150 mM PBS, which was seven times greater than that in water. After washing and freeze-drying, we obtained a dry powder consisting of spherical, non-aggregated particles, free from residual buffer, or unabsorbed lysozyme. The presence of lysozyme was confirmed by TGA and FT-IR, while N2 adsorption/desorption and SAXS analysis indicate that the protein is confined within the internal mesoporous structure. The dry powder exhibited excellent aerodynamic performance (fine particle fraction <5 µm of 70.32%). Lysozyme was released in simulated lung fluid in a sustained kinetics and maintaining high enzymatic activity (71-91%), whereas LYS-MSP were shown to degrade into aggregated nanoparticulate microstructures, reaching almost complete dissolution (93%) within 24 h. MSPs were nontoxic to in vitro lung epithelium. The study demonstrates disordered MSP as viable carriers to successfully deliver protein to the lungs, with high deposition and retained activity.

Dihydroartemisinin enhances the anti-tumour effect of photodynamic therapy by targeting PKM2-mediated glycolysis in oesophageal cancer cell

Photodynamic therapy (PDT) has been demonstrated to provide immediate relief of oesophageal cancer patients' re-obstruction and extend their lifespan. However, tumour regrowth may occur after PDT due to enhanced aerobic glycolysis. Previous research has confirmed the inhibitory effect of Dihydroartemisinin (DHA) on aerobic glycolysis. Therefore, the current study intends to investigate the function and molecular mechanism of DHA targeting tumour cell aerobic glycolysis in synergia PDT. The combined treatment significantly suppressed glycolysis in vitro and in vivo compared to either monotherapy. Exploration of the mechanism through corresponding experiments revealed that pyruvate kinase M2 (PKM2) was downregulated in treated cells, whereas overexpression of PKM2 nullified the inhibitory effects of DHA and PDT. This study proposes a novel therapeutic strategy for oesophageal cancer through DHA-synergized PDT treatment, targeting inhibit PKM2 to reduce tumour cell proliferation and metastasis.

Advances in therapeutic cancer vaccines: Harnessing immune adjuvants for enhanced efficacy and future perspectives

Preventive cancer vaccines are highly effective in preventing viral infection-induced cancer, but advances in therapeutic cancer vaccines with a focus on eliminating cancer cells through immunotherapy are limited. To develop therapeutic cancer vaccines, the integration of optimal adjuvants is a potential strategy to enhance or complement existing therapeutic approaches. However, conventional adjuvants do not satisfy the criteria of clinical trials for therapeutic cancer vaccines. To improve the effects of adjuvants in therapeutic cancer vaccines, effective vaccination strategies must be formulated and novel adjuvants must be identified. This review offers an overview of the current advancements in therapeutic cancer vaccines and highlights in situ vaccination approaches that can be synergistically combined with other immunotherapies by harnessing the adjuvant effects. Additionally, the refinement of adjuvant systems using cutting-edge technologies and the elucidation of molecular mechanisms underlying immunogenic cell death to facilitate the development of innovative adjuvants have been discussed.

Prospects of formamide as nitrogen source in biotechnological production processes

This review presents an analysis of formamide, focussing on its occurrence in nature, its functional roles, and its promising applications in the context of the bioeconomy. We discuss the utilization of formamide as an innovative nitrogen source achieved through metabolic engineering. These approaches underscore formamide's potential in supporting growth and production in biotechnological processes. Furthermore, our review illuminates formamide's role as a nitrogen source capable of safeguarding cultivation systems against contamination in non-sterile conditions. This attribute adds an extra layer of practicality to its application, rendering it an attractive candidate for sustainable and resilient industrial practices. Additionally, the article unveils the versatility of formamide as a potential carbon source that could be combined with formate or CO2 assimilation pathways. However, its attributes, i.e., enriched nitrogen content and comparatively limited energy content, led to conclude that formamide is more suitable as a co-substrate and that its use as a sole source of carbon for biomass and bio-production is limited. Through our exploration of formamide's properties and its applications, this review underscores the significance of formamide as valuable resource for a large spectrum of industrial applications. KEY POINTS: • Formidases enable access to formamide as source of nitrogen, carbon, and energy • The formamide/formamidase system supports non-sterile fermentation • The nitrogen source formamide supports production of nitrogenous compounds.

Advances in the use of local anesthetic extended-release systems in pain management

Pain management remains among the most common and largely unmet clinical problems today. Local anesthetics play an indispensable role in pain management. The main limitation of traditional local anesthetics is the limited duration of a single injection. To address this problem, catheters are often placed or combined with other drugs in clinical practice to increase the time that local anesthetics act. However, this method does not meet the needs of clinical analgesics. Therefore, many researchers have worked to develop local anesthetic extended-release types that can be administered in a single dose. In recent years, drug extended-release systems have emerged dramatically due to their long duration and efficacy, providing more possibilities for the application of local anesthetics. This paper summarizes the types of local anesthetic drug delivery systems and their clinical applications, discusses them in the context of relevant studies on local anesthetics, and provides a summary and outlook on the development of local anesthetic extended-release agents.

Biosynthesis of eriodictyol in citrus waster by endowing P450BM3 activity of naringenin hydroxylation

The flavonoid naringenin is abundantly present in pomelo peels, and the unprocessed naringenin in wastes is not friendly for the environment once discarded directly. Fortunately, the hydroxylated product of eriodictyol from naringenin exhibits remarkable antioxidant and anticancer properties. The P450s was suggested promising for the bioconversion of the flavonoids, but less naturally existed P450s show hydroxylation activity to C3' of the naringenin. By well analyzing the catalytic mechanism and the conformations of the naringenin in P450, we proposed that the intermediate Cmpd I ((porphyrin)Fe = O) is more reasonable as key conformation for the hydrolyzation, and the distance between C3'/C5' of naringenin to the O atom of CmpdI determines the hydroxylating activity for the naringenin. Thus, the "flying kite model" that gradually drags the C-H bond of the substrate to the O atom of CmpdI was put forward for rational design. With ab initio design, we successfully endowed the self-sufficient P450-BM3 hydroxylic activity to naringenin and obtained mutant M5-5, with kcat, Km, and kcat/Km values of 230.45 min-1, 310.48 µM, and 0.742 min-1 µM-1, respectively. Furthermore, the mutant M4186 was screened with kcat/Km of 4.28-fold highly improved than the reported M13. The M4186 also exhibited 62.57% yield of eriodictyol, more suitable for the industrial application. This study provided a theoretical guide for the rational design of P450s to the nonnative compounds. KEY POINTS: •The compound I is proposed as the starting point for the rational design of the P450BM3 •"Flying kite model" is proposed based on the distance between O of Cmpd I and C3'/C5' of naringenin •Mutant M15-5 with 1.6-fold of activity than M13 was obtained by ab initio modification.

Identifying factors controlling cellular uptake of gold nanoparticles by machine learning

There is strong interest to improve the therapeutic potential of gold nanoparticles (GNPs) while ensuring their safe development. The utility of GNPs in medicine requires a molecular-level understanding of how GNPs interact with biological systems. Despite considerable research efforts devoted to monitoring the internalisation of GNPs, there is still insufficient understanding of the factors responsible for the variability in GNP uptake in different cell types. Data-driven models are useful for identifying the sources of this variability. Here, we trained multiple machine learning models on 2077 data points for 193 individual nanoparticles from 59 independent studies to predict cellular uptake level of GNPs and compared different algorithms for their efficacies of prediction. The five ensemble learners (Xgboost, random forest, bootstrap aggregation, gradient boosting, light gradient boosting machine) made the best predictions of GNP uptake, accounting for 80-90% of the variance in the test data. The models identified particle size, zeta potential, GNP concentration and exposure duration as the most important drivers of cellular uptake. We expect this proof-of-concept study will foster the more effective use of accumulated cellular uptake data for GNPs and minimise any methodological bias in individual studies that may lead to under- or over-estimation of cellular internalisation rates.

Multiscale calculations reveal new insights into the reaction mechanism between KRASG12C and α, β-unsaturated carbonyl of covalent inhibitors

Utilizing α,β-unsaturated carbonyl group as Michael acceptors to react with thiols represents a successful strategy for developing KRASG12C inhibitors. Despite this, the precise reaction mechanism between KRASG12C and covalent inhibitors remains a subject of debate, primarily due to the absence of an appropriate residue capable of deprotonating the cysteine thiol as a base. To uncover this reaction mechanism, we first discussed the chemical reaction mechanism in solvent conditions via density functional theory (DFT) calculation. Based on this, we then proposed and validated the enzymatic reaction mechanism by employing quantum mechanics/molecular mechanics (QM/MM) calculation. Our QM/MM analysis suggests that, in biological conditions, proton transfer and nucleophilic addition may proceed through a concerted process to form an enolate intermediate, bypassing the need for a base catalyst. This proposed mechanism differs from previous findings. Following the formation of the enolate intermediate, solvent-assisted tautomerization results in the final product. Our calculations indicate that solvent-assisted tautomerization is the rate-limiting step in the catalytic cycle under biological conditions. On the basis of this reaction mechanism, the calculated kinact/ki for two inhibitors is consistent well with the experimental results. Our findings provide new insights into the reaction mechanism between the cysteine of KRASG12C and the covalent inhibitors and may provide valuable information for designing effective covalent inhibitors targeting KRASG12C and other similar targets.

Boronic acid inhibitors of penicillin-binding protein 1b: serine and lysine labelling agents

Penicillin-binding proteins (PBPs) contribute to bacterial cell wall biosynthesis and are targets of antibacterial agents. Here, we investigated PBP1b inhibition by boronic acid derivatives. Chemical starting points were identified by structure-based virtual screening and aliphatic boronic acids were selected for further investigations. Structure-activity relationship studies focusing on the branching of the boron-connecting carbon and quantum mechanical/molecular mechanical simulations showed that reaction barrier free energies are compatible with fast reversible covalent binding and small or missing reaction free energies limit the inhibitory activity of the investigated boronic acid derivatives. Therefore, covalent labelling of the lysine residue of the catalytic dyad was also investigated. Compounds with a carbonyl warhead and an appropriately positioned boronic acid moiety were shown to inhibit and covalently label PBP1b. Reversible covalent labelling of the catalytic lysine by imine formation and the stabilisation of the imine by dative N-B bond is a new strategy for PBP1b inhibition.

A comprehensive investigation of the anion inhibition profile of a β-carbonic anhydrase from Acinetobacter baumannii for crafting innovative antimicrobial treatments

This study refers to the intricate world of Acinetobacter baumannii, a resilient pathogenic bacterium notorious for its propensity at antibiotic resistance in nosocomial infections. Expanding upon previous findings that emphasised the bifunctional enzyme PaaY, revealing unexpected γ-carbonic anhydrase (CA) activity, our research focuses on a different class of CA identified within the A. baumannii genome, the β-CA, designated as 𝛽-AbauCA (also indicated as CanB), which plays a crucial role in the resistance mechanism mediated by AmpC beta-lactamase. Here, we cloned, expressed, and purified the recombinant 𝛽-AbauCA, unveiling its distinctive kinetic properties and inhibition profile with inorganic anions (classical CA inhibitors). The exploration of 𝛽-AbauCA not only enhances our understanding of the CA repertoire of A. baumannii but also establishes a foundation for targeted therapeutic interventions against this resilient pathogen, promising advancements in combating its adaptability and antibiotic resistance.

NanoConstruct: A web application builder of ellipsoidal nanoparticles for the investigation of their crystal growth, stability, and the calculation of atomistic descriptors

NanoConstruct is a state-of-the-art computational tool that enables a) the digital construction of ellipsoidal neutral energy minimized nanoparticles (NPs) in vacuum through its graphical user-friendly interface, and b) the calculation of NPs atomistic descriptors. It allows the user to select NP's shape and size by inserting its ellipsoidal axes and rotation angle while the NP material is selected by uploading its Crystallography Information File (CIF). To investigate the stability of materials not yet synthesised, NanoConstruct allows the substitution of the chemical elements of an already synthesized material with chemical elements that belong into the same group and neighbouring rows of the periodic table. The process is divided into three stages: 1) digital construction of the unit cell, 2) digital construction of NP using geometry rules and keeping its stoichiometry and 3) energy minimization of the geometrically constructed NP and calculation of its atomistic descriptors. In this study, NanoConstruct was applied for the investigation of the crystal growth of Zirconia (ZrO2) NPs when in the rutile form. The most stable configuration and the crystal growth route were identified, showing a preferential direction for the crystal growth of ZrO2 in its rutile form. NanoConstruct is freely available through the Enalos Cloud Platform (https://enaloscloud.novamechanics.com/riskgone/nanoconstruct/).

Exploring microstructures of metal-doped oxides via simulated Raman spectrum

Solid solution of metal-doped oxide has been widely used in material industry and catalysis process. Its performance is highly correlated with the distribution of doped ions. Due to the complex distribution of doped ions in solid solution and its variation with temperatures, to obtain the microstructures of metal-doped ions in solid solution remains a substantial challenge. Taken Ce1-xZrxO2 as a model, the global structure searching, structures proportion with temperature determined by Boltzmann distribution, and the weighted simulation Raman spectra were integrated to explore the microstructures of metal-doped solid solution oxides. It was further verified by application into rutile and anatase TiO2 mixture, indicating that the present method is feasible to deduce the microstructure of metal composite oxides. We anticipate that it provides a powerful solution to explore microstructures of solid solution and complex metal oxides.

Precision classification and quantitative analysis of bacteria biomarkers via surface-enhanced Raman spectroscopy and machine learning

The SERS spectra of six bacterial biomarkers, 2,3-DHBA, 2,5-DHBA, Pyocyanin, lipoteichoic acid (LTA), Enterobactin, and β-carotene, of various concentrations, were obtained from silver nanorod array substrates, and the spectral peaks and the corresponding vibrational modes were identified to classify different spectra. The spectral variations in three different concentration regions due to various reasons have imposed a challenge to use classic calibration curve methods to quantify the concentration of biomarkers. Depending on baseline removal strategy, i.e., local or global baseline removal, the calibration curve differed significantly. With the aid of convolutional neural network (CNN), a two-step process was established to classify and quantify biomarker solutions based on SERS spectra: using a specific CNN model, a remarkable differentiation and classification accuracy of 99.99 % for all six biomarkers regardless of the concentration can be achieved. After classification, six regression CNN models were established to predict the concentration of biomarkers, with coefficient of determination R2 > 0.97 and mean absolute error (MAE) < 0.27. The feature of important calculations indicates the high classification and quantification accuracies were due to the intrinsic spectral features in SERS spectra. This study showcases the synergistic potential of SERS and advanced machine learning algorithms and holds significant promise for bacterial infection diagnostics.

Transient radical species and oxygen colorimetric indicators grounded on phenothiazinium dyes

This study investigates four phenothiazinium dyes including methylene blue (MB) and three analogues containing auxochrome variation 2-4 as oxygen colorimetric indicators prepared by their incorporation into two types of oxygen permeable materials containing: a) polyvinyl alcohol substrate with additional TiO2 photocatalysts (PhOxIn), and b) carboxymethylcellulose polymer matrix containing glucose and KOH (ChOxIn). In vacuum packages where volumetric concentrations of oxygen were below 0.01 %, the leuco forms of the tested phenothiazinum dyes were readily oxidised, initiating the colour turn from white to blue. The redox processes involved were explored by experimental electron paramagnetic resonance EPR and UV-vis spectroscopic methods and further supported by theoretical quantum chemistry. The EPR experiments showed that the chemical oxidation of the leuco-form of the phenothiazinium dyes 1-4 produced transient aminyl radical species with the single electron mainly located at the nitrogen atom of the heterocyclic core. The formation of these transient aminyl species was also perceived by UV-vis spectroscopy, their absorption maxima situated in the 552-592 nm range being also supported by TD-DFT theoretical calculations.

Synthesis of biscarbazole derivative, detection of the "on-off" sensor property of Cu2+ by fluorimetry, and anti-cancer evaluation

Biscarbazole derivative probe (6) (Z)-2-(3-(((9-heptyl-9H-carbazol-3-yl)methylene)amino)-9H-carbazol-9-yl)ethan-1-ol containing an imine group, which is a sensitive and selective fluorescence chemosensor, was designed and synthesized for the effective evaluation of Cu2+ metal ion levels. The synthesized compounds were characterized using 1H NMR, 13C NMR, FT-IR, and MALDI-TOF MS (for compound 6) spectroscopic data. The interaction model between probe 6 and Cu2+ was determined by combining fluorescence methods, 1H NMR titration, Job's plot, and theoretical calculations. For probe 6, the fluorogenic recognition of Cu2+ was investigated by fluorescence spectroscopy, and the optical changes caused by Cu2+ ions were carried out in ACN/H2O (50:50) solution at pH 7.0. Fluorescence probe 6 was found to "turn-off" its fluorescence in the presence of paramagnetic Cu2+ ions. Probe 6 was determined to have a rapid response within 40s and showed a fluorescence response to Cu2+ with a low detection limit of 0.16 μM. Additionally, in vitro anticancer activity and cell imaging studies of probe 6 against the prostate cell line (PC-3) were performed.

Carrier dynamics competition in the nanocrystal-molecule complex for triplet generation studied by transient-absorption spectroscopy

Owing to the long-lived decay of triplet excited state, extensive efforts have been devoted to efficient triplet generation for applications covering triplet-triplet annihilation for photon upconversion, photocycloaddition and photoredox catalysis. Among the candidates, nanocrystal-molecule complexes have received tremendous attention for triplet generation because of easier spin flip and negligible energy loss during intersystem crossing. However, the triplet energy transfer (TET) from nanocrystals (NCs) to molecules can be very complicated in actual situation due to intricate energy level alignment and inevitable defect states, which often involves various decay pathes of the excited state competing with TET. Understanding the detailed carrier dynamics in such complexes is strongly necessary for related applications. Here, a CdSe-TCA (5-tetracene carboxylic acid) complex with a Type-II like energy level alignment is synthesized through precisely adjusting the dimension of CdSe NC. Based on series of spectral measurements, especially the transient absorption (TA) spectroscopy, the results show various carrier dynamics including hole-transfer-mediated TET, Förster resonance energy transfer (FRET) and carrier trapping. Although the carrier trapping by defect states in CdSe NC is revealed not associated with the TET from CdSe to TCA, the FRET is proved to competing with the TET process. Both the FRET and defect states should be refrained for efficient TET in such complexes. This study could provide further insight for understanding the carrier dynamics competition in NC-molecule complexes for triplet generation and benefit related optoelectronics applications.

Insights into the photoactivatable CO releasing properties of dicarbonyl Ru(II) complex with 8-amino quinoline ligand: Experimental and theoretical studies

Reaction between the polymeric [RuCl2(CO)2]n and the N,N-bidentate ligand, 8-amino-quinoline (Quin), in methanol, afforded the photoactivated CO releasing molecule with the formula of trans-(Cl,Cl)-[RuCl2(CO)2Quin]. In the presence of biomolecules or in solvents with varying polarity and coordinating abilities, the solvatochromic characteristics and dark stability were investigated. A new board band emerged in the visible spectrum during the illumination, and its position varies according to the type of solvent used, indicating the role of the solvent in controlling the nature of the CO-depleted species. Spectral methods were used in combination with density functional theory simulations to get insight into the local minimum structure and the electronic properties of the Ru(II) complex. The results of the myoglobin assay showed that within the first two hours of illumination, one of the two CO molecules was released. The cytotoxic properties of the Ru(II)-based complex were investigated against normal mice bone marrow stromal cells and malignant human acute monocytic leukaemia cells.

Dual NIR-channel fluorescent probe for detecting ONOO- in vitro and vivo

As one of endogenous reactive oxygen species (ROS), peroxynitrite (ONOO-) performs various functions in both pathological and physiological mechanisms. In this work, an optical and near-infrared (NIR) fluorescent probe (NX), which based on 3-dihydro-1H-xanthene and 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) group was designed and prepared to detect ONOO-. This probe revealed an obvious optical and a fluorescent response when ONOO- was present and it exhibited higher selectivity over other ROS. Especially, the dual NIR fluorescence changes at 660 and 800 nm allowed quantitative detection of ONOO- in the range of 15-40 μM, and the detection limit was 82 nM. Finally, the probe was effectively employed to visualize exogenous and endogenous ONOO- in HepG2 cells and zebrafish, respectively. All the results indicated the dual NIR-channel probe could serve as a potent detecting tools in studying ONOO- in vitro and in vivo.

A highly efficient, selective, reversible and ultra-sensitive fluorescence "Turn-ON" chemosensor for aluminium ions by a novel Schiff base

The synthesis of a Schiff base-based chemosensor, denoted as H6L, was accomplished through the condensation reaction of Isophthalohydrazide and 2,6-dihydroxybenzaldehyde in an ethanol solvent. The resulting compound was further characterized using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, as well as high-resolution mass spectrometry (HRMS). Extensive research has been conducted on several facets of metal sensing phenomena, revealing that the Schiff base H6L demonstrates discerning and expeditious fluorescence sensing characteristics specifically towards Al (III) in acetonitrile. The purported method detects Al (III) can be ascribed to the suppression of photo-induced electron transfer (PET) and the enhanced chelation-induced fluorescence (CHEF). The stoichiometry of metal-ligand complexes (2:1) was determined using Job's plots titrations, HRMS and subsequently confirmed using NMR titration studies. The H6L sensors demonstrated remarkable fluorescence sensing capabilities in acetonitrile, with a low detection limit (LOD) of 0.44 μM. This LOD is suitably low for the detection of Al3+, which is commonly found in many environmental and biological systems. Fluorescence lifetime measurement provides additional evidence of complexation of H6L with Al (III). The reversibility of the sensor was demonstrated through the introduction of pyrophosphate (PPi), which forms a complex with aluminium ions, thereby releasing the chemo sensor for subsequent utilization. The findings suggest that H6L has the potential to serve as a viable probe for the detection and identification of Al3+ ions.

Fluorescent aptasensors for sensitive detection of lead ions based on structure-switching DNA beacon probe and exonuclease I-mediated signal amplification

Herein, two simple fluorescent signal-on sensing strategies for detecting lead ions (Pb2+) were established based on structure-switching aptamer probes and exonuclease-assisted signal amplification strategies. Two hairpin-structure fluorescent probes with blunt-ended stem arms were designed by extending the base sequence of Pb2+ aptamer (PS2.M) and labelling the probes with FAM (in probe 1) and 2-aminopurine (2-AP) (in probe 2), respectively. In method 1, graphene oxide (GO) was added to adsorb probe 1 and quench the fluorescence emission of FAM to achieve low fluorescent background. In method 2, fluorescent 2-AP molecule inserted into the double-stranded DNA of probe 2 was quenched as a result of base stacking interactions, leading to a simplified, quencher-free approach. The addition of Pb2+ can induce the probes to transform into G-quadruplex structures, exposing single DNA strands at the 3' end (the extended sequences). This exposure enables the activation of exonuclease I (Exo I) on the probes, leading to the cleavage effect and subsequent release of free bases and fluorophores, thereby resulting in amplified fluorescence signals. The two proposed methods exhibit good specificity and sensitivity, with detection limits of 0.327 nM and 0.049 nM Pb2+ for method 1 and method 2, respectively, and have been successfully applied to detect Pb2+ in river water and fish samples. Both detection methods employ the structure-switching aptamer probes and can be completed in two or three steps without the need for complex analytical instruments. Therefore, they have a broad prospect in the sensitive and simple detection of lead ion contamination in food and environmental samples.

An ESIPT + AIE based dual-response fluorescent probe for continuous detection of PhSH and HClO and visualization of PhSH-induced oxidative stress in living cells

As a valuable industrial chemical, thiophenol (PhSH) is poisonous, which can be easily absorbed by the human body, leading to many serious health issues. In addition, PhSH-triggered oxidative stress is considered to be related with the pathogenesis and toxicity of PhSH. Therefore, efficient methods for monitoring PhSH and ROS production induced by PhSH in living systems are very meaningful and desired. Herein, we reasonably developed a facile dual-response fluorescent probe (HDB-DNP) by incorporating the dinitrophenyl (DNP) group into a novel methylthio-substituted salicylaldehyde azine (HDB) with AIE and ESIPT features. The probe itself was non-fluorescent owing to the strong quenching effect of DNP group. In the presence of PhSH, HDB-DNP gave an intense red fluorescence (610 nm), which can rapidly switch to green fluorescence (510 nm) upon further addition of HClO, allowing the successive detection of PhSH and HClO in two well-separated channels. HDB-DNP proved to be a very promising dual-functional probe for rapid (PhSH: < 17 min; HClO: 10 s) and selective detection of PhSH and HClO in physiological conditions with low detection limit (PhSH: 13.8 nM; HClO: 88.6 nM). Inspired by its excellent recognition properties and low cytotoxicity, HDB-DNP was successfully applied for monitoring PhSH and PhSH-induced HClO generation in living cells with satisfactory results, which may help to better understand the pathogenesis of PhSH-related diseases.

Advancing optoelectronic characteristics of Diketopyrrolopyrrole-Based molecules as donors for organic and as hole transporting materials for perovskite solar cells

A stable and efficient hole-transport material (HTM) is crucial for high-performance perovskite solar cells (PSCs). A 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-MeOTAD) being used widely to prepare highly efficient PSCs. However, Spiro-MeOTAD has some limitations due to its complex synthesis, which increases its cost, and it also requires dopants to improve its performance. Therefore, we designed thirteen unique small-molecule-based HTMs (MK1-MK13), which are easy to synthesize, highly cost-effective, and don't require dopants to prepare efficient PSCs. Their electrical and optical properties are then investigated theoretically using advanced quantum chemical approaches. The designed molecules showed lower energy gaps and improved optical and optoelectronic characteristics because of the improved phase inversion geometry. The detailed photo-physical and optoelectronic characteristics have been studied using density functional theory (DFT) and time-dependent (TD-DFT) calculations. Moreover, we investigated the impact of holes and electrons and the density of states, open-circuit voltage, frontier molecular orbital, transition density matrix, and other structural and photovoltaic characteristics of these materials. Among these, the MK3 molecule possesses the much narrower optical band gap of 1.04 eV and absorbance (λ max) of 684 nm, respectively. In addition, a profound investigation of the MK3/PC61BM blend shows excellent charge transfer at the acceptor-donor interface. Therefore, our proposed technique is necessary for generating appropriate photovoltaic materials for efficient optoelectronic devices and is helpful in further advancing the field.

Styrylbenzoquinoline dyads as a new type of fluorescing photochromes operating via [2 + 2] photocycloaddition mechanism: Optimization of the structure

We synthesized and studied a novel bichromophoric dyad in which bridging methylene groups link two styrylbenzo[f]quinoline (SBQ) photochromes to a salicylic acid residue. The dyad was designed for use as a fluorescent P-type photochrome acting via a [2 + 2] photocycloaddition (PCA) reaction. Compared to previously studied dyads, a change in the attachment handle and shortening of the bridging groups resulted in simultaneous rise of the quantum yields of both fluorescence and PCA. Under light irradiation, two competitive reversible reactions occurred in the dyad. The first is photoisomerization between the trans- and cis- isomers of the SBQ moieties. The second is PCA. The latter process was predominant and resulted in the formation of the cyclobutane ring bearing two benzo[f]quinoline (BQ) groups. In the ground S0 state, NMR data and DFT calculations indicated the formation of folded dyad conformers whose structure is pre-organized for PCA due to π-stacking interactions of two SBQ moieties. In the excited dyad, steady-state and time-resolved nanosecond fluorescence spectroscopy revealed the formation of an excimer, which was assumed to be a precursor of cyclobutane. Due to the fluorescence properties of SBQ and BQ, both dyad and cyclobutane fluoresce and can serve as a color-correlated multicolor fluorescence photoswitch. A simple approach is proposed for predicting the relationship between the spectral properties of the dyad and cyclobutane, which are the open and closed isomers of a new type of photochromes. The approach uses the dependence of the position of the maximum of the absorption band of an aromatic compound on the size of the π-system, as well as the fact that the sizes of the π-systems of the dyad and cyclobutane are related by a simple relation.

Hydrostatic pressure effect on excited state properties of room temperature phosphorescence molecules: A QM/MM study

Stimulus-responsive organic room temperature phosphorescence (RTP) materials exhibit variations in their luminescent characteristics (lifetime and efficiency) upon exposure to external stimuli, including force, heat, light and acid-base conditions, the development of stimulus-responsive RTP molecules becomes imperative. However, the inner responsive mechanism is unclear, theoretical investigations to reveal the relationship among hydrostatic pressures, molecular structures and photophysical properties are highly desired. Herein, taking the Se-containing RTP molecule (SeAN) as a model, based on the dispersion corrected density functional theory (DFT-D), the combined quantum mechanics and molecular dynamics (QM/MM) method and thermal vibration correlation function (TVCF) theory, the influences of hydrostatic pressure on molecular structures, transition properties as well as lifetimes and efficiencies of RTP molecule are theoretically studied. Results show that extended lifetime and enhanced efficiency are observed at 2 Gpa compared with molecule at normal pressure, and this is related with the small reorganization energy and large oscillator strength. Moreover, due to the small energy gap (0.34 eV) and remarkable spin-orbit coupling (SOC) constant (8.56 cm-1) between first singlet excited state and triplet state, fast intersystem crossing (ISC) process is determined for molecule at 6 Gpa. Furthermore, the intermolecular interactions are visualized using independent gradient model based on Hirshfeld partition (IGMH) and the changes of molecular packing modes, SOC values, lifetimes and efficiencies with pressures are detected. These results reveal the relationship between molecular structures and RTP properties. Our work provides theoretical insights into the hydrostatic pressure response mechanism and could promote the development new efficient stimulus-responsive molecules.

Terminal halogen-containing rod-like liquid crystals: Synthesis, self-assembly, photophysical and mechanochromism properties

Five series of cyanostilbene-based rod-like liquid crystals containing one different terminal atom (H, F, Cl, Br and I) at one end and one terminal aliphatic chain with different numbers of carbon atoms at the other end were reported by Suzuki coupling and Knoevenagel reactions. The influence of terminal halogen atoms and terminal chain length on the self-assembly, AIE behavior, temperature-dependent emission and mechanochromism behavior was explored by POM, DSC, XRD, SEM, absorption spectra and emission spectra. All the compounds are enantiotropic liquid crystals. The lowest non-halogen substituted homologue exhibited solo N phase, but the higher non-halogen substituted homologues exhibited mesogenic transition from SmA phase to N phase upon rising temperature. All the lowest halogen substituted homologues exhibited mesogenic transition from SmA phase to N phase upon rising temperature and all the higher homologues only exhibited SmA. The distinct mesogenic phase transition could be attributed to the intermolecular interaction produced by terminal halogen and the rigidity of the terminal aliphatic chain. All the non-halogen substituted compounds and halogen substituted compounds with smaller terminal halogen atom (F, Cl and Br atom) exhibited AIE behaviors, whereas the iodinated compounds exhibited extremely weak emission in solution and aggregated states due to the heavy atoms effect. These compounds also exhibited distinct solid-state emission with blue or cyan fluorescence, which could be quenched by increasing temperature. The reversible mechanochromism behavior was also achieved in all the compounds. The mechanical force induced quench in emission in non-halogen substituted compounds and halogen substituted compounds with smaller terminal halogen atom (F, Cl and Br atom), whereas enhancement in iodinated compounds. The reversible mechanochromism behavior endowed these compounds with potential applications in rewritable paper and anti-counterfeiting. The interesting properties in these liquid crystals would be attributed to the balance of the halogen-halogen interactions, heavy atom effect, steric-hindrance effect and chain length. These investigations would be helpful to understand the relationship between chemical structures and properties.

Novel ratiometric fluorescent probe with large Stokes shift for selective sensing and imaging of Zn2+ in live cell

A novel ratiometric fluorescent probe, namely 5-[(3-dicyanoylidene -5.5-dimethyl) cyclohexenyl-1-ethenyl] salicylaldehyde-3'-hydroxybenzohydrazone (DCSH) is presented for the selective sensing of Zn2+ ion in acetonitrile/water (2/3, pH 7.4) solution. Introducing Zn2+ ions notably caused the peak emission of DCSH to shift from 560 nm to 646 nm, accompanied with a significant enhancement of its intensity. A vivid change in fluorescence color from yellow to red facilitated the immediate identification of Zn2+ ions by visual observation. DCSH exhibits substantial Stokes shifts (110 and 196 nm), rapid detection capability (within 10 s) and high sensitivity to Zn2+ ions, achieving a limit of detection of 31.2 nM. The response mechanism is supposed to involve the block of C = N bond isomerization and excited state intramolecular proton transfer (ESIPT) along with the enhancement of fluorescence through chelation (CHEF) effect. DCSH was effectively utilized for ratiometric fluorescence imaging to monitor exogenous Zn2+ concentrations in HeLa cells. Significantly, DCSH is capable of monitoring elevated levels of Zn2+ ion during apoptosis induced by L-Buthionine sulfoximine (BSO).

Raman spectrometer with vertical flow method for solutions containing organic solvents

The vertical flow (VF) method improves generation and collection efficiency in Raman spectroscopy. It enhances all Raman signals, including undesired signals of organic solvents having a considerably large Raman cross section. We constructed a Raman spectrometer using the VF method to overcome this drawback and introduced a spatial line rejection mask to eliminate unnecessary bands. In addition, the design of the VF unit was improved to resist organic solvents. A VF unit with a 60-µm pinhole enhanced the signal 168 times. The spatial mask effectively eliminated the large Raman bands of the solvent and enabled a longer exposure time. The increase in the dynamic range improved the signal-to-noise ratio by 10 % in methanol and acetonitrile measurements. Raman spectrometer with the VF method and spatial mask enables us to record the Raman spectrum of solute molecules without the disturbance of solvent bands.

Effect of Nk-lysin peptides on bacterial growth, MIC, antimicrobial resistance, and viral activities

NK-lysins from chicken, bovine and human are used as antiviral and antibacterial agents. Gram-negative and gram-positive microorganisms, including Streptococcus pyogenes, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Shigella sonnei, Klebsiella pneumoniae and Salmonella typhimurium, are susceptible to NK-lysin treatment. The presence of dominant TEM-1 gene was noted in all untreated and treated bacteria, while TOHO-1 gene was absent in all bacteria. Importantly, β-lactamase genes CTX-M-1, CTX-M-8, and CTX-M-9 genes were detected in untreated bacterial strains; however, none of these were found in any bacterial strains following treatment with NK-lysin peptides. NK-lysin peptides are also used to test for inhibition of infectivity, which ranged from 50 to 90% depending on NK-lysin species. Chicken, bo vine and human NK-lysin peptides are demonstrated herein to have antibacterial activity and antiviral activity against Rotavirus (strain SA-11). On the basis of the comparison between these peptides, potent antiviral activity of bovine NK-lysin against Rotavirus (strain SA-11) is particularly evident, inhibiting infection by up to 90%. However, growth was also significantly inhibited by chicken and human NK-lysin peptides, restricted by 80 and 50%, respectively. This study provided a novel treatment using NK-lysin peptides to inhibit expression of β-lactamase genes in β-lactam antibiotic-resistant bacterial infections.

Atomically dispersed copper-zinc dual sites anchored on nitrogen-doped porous carbon toward peroxymonosulfate activation for degradation of various organic contaminants

Single-atom catalysts (SACs) have been widely studied in Fenton-like reactions, wherein their catalytic performance could be further enhanced by adjusting electronic structure and regulating coordination environment, although relevant research is rarely reported. This text elucidates fabrication of dual atom catalyst systems aimed at augmenting their catalytic efficiency. Herein, atomically dispersed copper-zinc (Cu-Zn) dual sites anchored on nitrogen (N)-doped porous carbon (NC), referred to as CuZn-NC, were synthesized using cage-encapsulated pyrolysis and host-guest strategies. The CuZn-NC catalyst exhibited high activity in activation of peroxymonosulfate (PMS) for degradation of organic pollutants. Based on synergistic effects of adjacent Cu and Zn atom pairs, CuZn-NC (PMS) system achieved 94.44 % bisphenol A (BPA) degradation in 24 min. The radical pathway predominated, and coexistence of non-radical species was demonstrated for BPA degradation in CuZn-NC/PMS system. More importantly, CuZn-NC/PMS system showed generality for degradation of various refractory contaminants. Our experiments indicate that CuZn-N sites on CuZn-NC act as active sites for bonding PMS molecules with optimal binding energy, while pyrrolic N sites are considered as adsorption sites for organic molecules. Overall, this research designs diatomic site catalysts (DACs), with promising implications for wastewater treatment.

Selective exposure of (111) crystal plane in Pd49Ag30Te4 by Tb doping to weaken Pd - C bond and promote electroreduction of CO2 to CO

Employing electric energy to convert carbon dioxide (CO2) into valuable small molecules is a potentially practical method in energy storage and greenhouse gas alleviation. A huge challenge for electrocatalytic CO2 reduction is to reduce overpotential to improve energy efficiency. Herein, we demonstrate that doping alloy Pd49Ag30Te4 (PAT) with rare-earth element Tb is beneficial for selective exposure of (111) crystal plane, which is a highly active crystal plane for producing carbon monoxide (CO). The as-prepared Tb2.9PAT exhibited high electrocatalytic performance with 95.7 % CO faradic efficiency at - 0.8 V (vs RHE), far exceeding that of PAT, and coupled with good durability. In situ spectral study and theoretical calculations disclose that the introduction of Tb regulates the d-band center of PAT alloy, weakens the Pd - C bonding ability, and promotes the desorption of *CO in the rate-determining step. This study provides a method for doping induced selective exposure of crystal face, which provides new idea for improving catalytic performance.

Bi-magnetic Mn3O4@Ni core-shell binary superparticles: Self-assembly preparation and magnetic behaviors

Binary superparticles formed by self-assembling two different types of nanoparticles may utilize the synergistic interactions and create advanced multifunctional materials. Bi-magnetic superparticles with a core-shell structure have unique properties due to their specific spatial configurations. Herein, we built Mn3O4@Ni core-shell binary superparticles via an emulsion self-assembly technique. The superparticles are generated with a spherical morphology, and have a typical average size of about 240 nm. By altering the ratio of the two magnetic nanoparticles, the thickness of Ni shells can be adjusted. Oleic acid ligands are crucial for the formation of core-shell structure. Magnetic analysis suggests that core-shell superparticles display dual-phase magnetic interactions, contrasting with the single-phase magnetic behaviors of commonly core-shell magnetic nanoparticles. The calculation on the effective magnetic anisotropy constants indicates that the presence of Ni shell layers reduces the dipole interactions among the Mn3O4 core particles. Due to the presence of Ni nanoparticle shells, the blocking temperature of Mn3O4 is reduced, while the Curie temperature of Mn3O4 is independent on Ni content. Tunable magnetic properties can be achieved by modulating the Ni nanoparticle shell thickness. This study offers insights for the development of core-shell superparticles with varied magnetic characteristics.

Acoustofluidic one-step production of plasmonic Ag nanoparticles for portable paper-based ultrasensitive SERS detection of bactericides

SERS measurements for monitoring bactericides in dairy products are highly desired for food safety problems. However, the complicated preparation process of SERS substrates greatly impedes the promotion of SERS. Here, we propose acoustofluidic one-step synthesis of Ag nanoparticles on paper substrates for SERS detection. Our method is economical, fast, simple, and eco-friendly. We adopted laser cutting to cut out appropriate paper shapes, and aldehydes were simultaneously produced at the cutting edge in the pyrolysis of cellulose by laser which were leveraged as the reducing reagent. In the synthesis, only 5 μL of Ag precursor was added to complete the reaction, and no reducing agent was used. Our recently developed acoustofluidic device was employed to intensely mix Ag+ ions and aldehydes and spread the reduced Ag nanoparticles over the substrate. The SERS substrate was fabricated in 1 step and 3 min. The standard R6G solution measurement demonstrated the excellent signal and prominent uniformity of the fabricated SERS substrates. SERS detection of the safe concentration of three bactericides, including tetracycline hydrochloride, thiabendazole, and malachite green, from food samples can be achieved using fabricated substrates. We take the least cost, time, reagents, and steps to fabricate the SERS substrate with satisfying performance. Our work has an extraodinary meaning for the green preparation and large-scale application of SERS.

Regulating the solvation structure of Zn2+ via glycine enables a long-cycling neutral zinc-ferricyanide flow battery

Zinc-based flow batteries hold potential promise for extensive energy storage on a large scale owing to their high energy density and low cost. However, their widespread implementation is impeded by challenges associated with zinc (Zn) dendrites and side reactions like the hydrogen evolution reaction on the anode. Theoretical calculations have confirmed that glycine (Gly) has the ability to coordinate with Zn2+, displacing H2O molecules in the solvation shell, thereby restoring the solvation structure of Zn2+ and promoting the release of reactive Zn2+ during plating/stripping processes. As a result, the incorporation of Gly into the anolyte of a neutral zinc-ferricyanide (Zn/Fe) flow battery (ZIFB) effectively inhibits the formation of Zn dendrites and impedes side reactions, leading to highly reversible and stable Zn plating/stripping reactions. A Zn||Zn symmetric flow battery utilizing Gly in the anolyte demonstrated extended cycling durability, lasting over 550 h at a current density of 30 mA cm-2, in contrast to the failure of a Gly-free anolyte system after 150 h. Notably, this approach facilitates a neutral ZIFB achieving an impressive energy efficiency exceeding 70 %, even at a high current density of 70 mA cm-2, with a cycle lifespan exceeding 800 h (33 days) at a current density of 30 mA cm-2. Conversely, the neutral ZIFB lacking Gly showed a significantly shorter cycle life of only 260 h under identical operational conditions (30 mA cm-2). Due to the economic benefits of Gly and the proposed user-friendly route, this strategy demonstrates great potential for promoting the widespread adoption of zinc-based flow batteries with improved performance for practical use.

Rational designing NiVO3@CoNi-MOF heterostructures on activated carbon cloth for high-performance asymmetric supercapacitors and oxygen evolution reaction

Binder-free self-supported carbon cloth electrode provides novel strategies for the preparation of MOFs, effectively improving the conductivity and promoting charge transfer. Combining MOFs with vanadate to form a unique heterogeneous structure provides a large specific surface area and more active sites, further enhancing the kinetics of MOFs. Herein, a self-supported carbon cloth electrode is prepared by in-situ growth of CoNi-MOFs on activated carbon cloth (AC) and coating with NiVO3. The heterostructure increases the specific surface area and exposes more active sites to promote the adsorption and diffusion of ions, thus enhancing the kinetic activity and optimizing charge storage behavior. As expected, the NiVO3@CoNi-MOF/AC exhibits a specific capacitance of up to 19.20 F/cm2 at 1 mA/cm2. The asymmetric supercapacitors (ASCs) assembled by NiVO3@CoNi-MOF/AC and annealed activated carbon cloth achieve an energy density of 1.27 mWh/cm2 at a power density of 4 mW/cm2 and have a capacitance retention of 96.43 % after 10,000 cycles. In addition, the NiVO3@CoNi-MOF/AC as electrocatalyst has an overpotential of 370 mV at 10 mA/cm2 and a Tafel slope of 208 mV dec-1, demonstrating remarkable electrocatalytic oxygen evolution reaction performance. These unique heterostructures endow the electrode with more electrochemical selectivity and provide new key insights for designing multifunctional materials.

A singlet oxygen-storing covalent organic framework for "Afterglow" photodynamic therapy

Photodynamic therapy (PDT) is an emerging treatment but often restricted by the availability of oxygen. Enhancing the lifespan of singlet oxygen (1O2) by fractionated generation is an effective approach to improve the efficacy of PDT. Herein, an imine-based nanoscale COF (TpDa-COF) has been synthesized and functionalized with a pyridone-derived structure (Py) to create a 1O2-storing nanoplatform TpDa-COF@Py, which can reversibly capture and release 1O2. Under 660 nm laser exposure, Py interacts with 1O2 produced by the porphyrin motif in COF backbones to generate 1O2-enriched COF (TpDa-COF@Py + hv), followed by the release of 1O2 through retro-Diels-Alder reactions at physiological temperatures. The continuous producing and releasing of 1O2 upon laser exposure leads to an "afterglow" effect and a prolonged 1O2 lifespan. In vitro cytotoxicity assays demonstrates that TpDa-COF@Py + hv exhibits an extremely low half-maximal inhibitory concentration (IC50) of 0.54 µg/mL on 4T1 cells. Remarkably, the Py-mediated TpDa-COF@Py nanoplatform demonstrates enhanced cell-killing capability under laser exposure, attributed to the sustained 1O2 cycling, compared to TpDa-COF alone. Further in vivo assessment highlights the potential of TpDa-COF@Py + hv as a promising strategy to enhance phototheronostics and achieve effective tumor regression. Accordingly, the study supplies a generalized 1O2 "afterglow" nanoplatform to improve the effectiveness of PDT.

Facile Low-Temperature synthesis of novel carbon nitrides for efficient conversion of carbon dioxide into Value-Added chemicals

The interest in using carbon nitrides (CN) for CO2 conversion has stimulated extensive research on CN synthesis. Herein, we report the synthesis of two novel CN materials using low-cost commercially available precursors at low temperatures in a short duration of time. Two CN materials, one derived from 5-amino tetrazole (named 4NZ-CN) and the other derived from 3, 5-diamino-1, 2, 4-triazole (named 3NZ-CN) precursors, are prepared by refluxing these precursors for 2 h at 100 °C. 4NZ-CN and 3NZ-CN catalysts show higher surface areas (55.80 and 52.00 m2 g-1) and more basic sites (10.05 and 5.65 mmol g-1) than the conventional graphitic carbon nitride (g-C3N4) derived from melamine, for which the corresponding values are 9.20 m2 g-1 and 0.62 mmol g-1, respectively. In addition, both CN exhibit a 3-fold higher catalytic activity for CO2 cycloaddition to epoxides than g-C3N4. The structure-activity relationship was ascertained using a combination of experimental and computational studies, and a catalytic mechanism was proposed. This work provides a facile strategy for the synthesis of novel CN materials at relatively low temperatures, and the developed catalysts show remarkable performance in the conversion of CO2 to value-added chemicals.

Single-atom Mn sites confined into hierarchically porous core-shell nanostructures for improved catalysis of oxygen reduction

Applications of zinc-air batteries are partially limited by the slow kinetics of oxygen reduction reaction (ORR); Thus, developing effective strategies to address the compatibility issue between performance and stability is crucial, yet it remains a significant challenge. Here, we propose an in situ gas etching-thermal assembly strategy with an in situ-grown graphene-like shell that will favor Mn anchoring. Gas etching allows for the simultaneous creation of mesopore-dominated carbon cores and ultrathin carbon layer shells adorned entirely with highly dispersed Mn-N4 single-atom sites. This approach effectively resolves the compatibility issue between activity and stability in a single step. The unique core-shell structure allows for the full exposure of active sites and effectively prevents the agglomerations and dissolution of Mn-N4 sites in cores. The corresponding half-wave potential for ORR is up to 0.875 V (vs. reversible hydrogen electrode (RHE)) in 0.1 M KOH. The gained catalyst (Mn-N@Gra-L)-assembled zinc-air battery has a high peak power density (242 mW cm-2) and a durability of ∼ 115 h. Furthermore, replacing the zinc anode achieved a stable cyclic discharge platform of ∼ 20 h at varying current densities. Forming more fully exposed and stable existing Mn-N4 sites is a governing factor for improving the electrocatalytic ORR activity, significantly cycling durability, and reversibility of zinc-air batteries.

Highly deformable bi-continuous conducting polymer hydrogels for electrochemical energy storage

Conducting polymer hydrogels with inherent flexibility, ionic conductivity and environment friendliness are promising materials in the fields of energy storage. However, a trade-off between mechanical and electrochemical properties has limited the development of flexible/stretchable conducting polymer hydrogel electrodes, owing to the intrinsic conflict among mechanical and electrical phases. Here, we report a reliable design to enable conducting polymer with both exceptional mechanical and electrical/electrochemical performance through the construction of bi-continuous conducting polymer crosslinked network. The resultant bi-continuous conducting polymer hydrogels (BCPH) demonstrate significantly improved mechanical and electrochemical properties compared to the conventional conducting polymer hydrogel (CPH) electrode. BCPH presents a high specific capacitance of 715 F g-1 at 0.5 A/g, a high mechanical strength (∼1 MPa) and a large stretchability (∼300%). Enabled by such intrinsically deformability and electrochemical properties, we further demonstrate its utility in flexible solid-state supercapacitor (FSSC), which exhibits an outstanding specific capacitance of 760 mF cm-2 at 2 mA cm-2, excellent electrochemical stability with 81% capacitance retention after 5000 charge/discharge cycles, and superior bending cycle stability. This simple and scalable strategy provides a platform for the fabrication of high-performance conducting hydrogel electrodes for various wearable electronic equipment.

Comparative study on CeO2 catalysts with different morphologies and exposed facets for catalytic ozonation: performance, key factor and mechanism insight

Morphology and facet effects of metal oxides in heterogeneous catalytic ozonation (HCO) are attracting increasing interests. In this paper, the different HCO performances for degradation and mineralization of phenol of seven ceria (CeO2) catalysts, including four with different morphologies (nanorod, nanocube, nanooctahedron and nanopolyhedron) and three with the same nanorod morphology but different exposed facets, are comparatively studied. CeO2 nanorods with (110) and (100) facets exposed show the best performance, much better than that of single ozonation, while CeO2 nanocubes and nanooctahedra show performances close to single ozonation. The underlying reason for their different HCO performances is revealed using various experimental and density functional theory (DFT) calculation results and the possible catalytic reaction mechanism is proposed. The oxygen vacancy (OV) is found to be pivotal for the HCO performance of the different CeO2 catalysts regardless of their morphology or exposed facet. A linear correlation is discerned between the rate of catalytic decomposition of dissolved ozone (O3) and the density of Frenkel-type OV. DFT calculations and in-situ spectroscopic studies ascertain that the existence of OV can boost O3 activation on both the hydroxyl (OH) and Ce sites of CeO2. Conversely, various facets without OV exhibit similar O3 adsorption energies. The OH group plays an important role in activating O3 to produce hydroxyl radical (∙OH) for improved mineralization. This work may offer valuable insights for designing Facet- and OV-regulated catalysts in HCO for the abatement of refractory organic pollutants.

Enhancing electrochemical water-splitting efficiency with superaerophobic nickel-coated catalysts on Chinese rice paper

The quest for efficient hydrogen production highlights the need for cost-effective and high-performance catalysts to enhance the electrochemical water-splitting process. A significant challenge in developing self-supporting catalysts lies in the high cost and complex modification of traditional substrates. In this study, we developed catalysts featuring superaerophobic microstructures engineered on microspherical nickel-coated Chinese rice paper (Ni-RP), chosen for its affordability and exceptional ductility. These catalysts, due to their microspherical morphology and textured surface, exhibited significant superaerophobic properties, substantially reducing bubble adhesion. The nickel oxy-hydroxide (NiOxHy) and phosphorus-doped nickel (PNi) catalysts on Ni-RP demonstrated effective roles in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), achieving overpotentials of 250 mV at 20 mA cm-2 and 87 mV at -10 mA cm-2 in 1 M KOH, respectively. Moreover, a custom water-splitting cell using PNi/Ni-RP and NiOxHy/Ni-RP electrodes reached an impressive average voltage of 1.55 V at 10 mA cm-2, with stable performance over 100 h in 1 M KOH. Our findings present a cost-effective, sustainable, and easily modifiable substrate that utilizes superaerophobic structures to create efficient and durable catalysts for water splitting. This work serves as a compelling example of designing high-performance self-supporting catalysts for electrocatalytic applications.

Preparation of fluorescent polyurethane microspheres and their applications as reusable sensor for 4-nitrophenol detection and as microplastics model for visualizing polyurethane in cells and zebrafish

Fluorescent microspheres are of significant interests due to their wide applications in biotechnology fields. However, their preparation presents several challenges, such as the need for dye labeling, the complexity of materials and often sophisticated preparation conditions. Here a simple process for hydrophilic and crosslinked polyurethane (CPU) microspheres, with carboxyl groups on the surface via one-step precipitation polymerization in 40 min, is presented. The microsphere size is easily adjusted by varying experimental conditions. CPU microspheres exhibit high thermal and pH stability with good redispersibility in water, and emit fluorescence without any modification or dye labeling. The emission mechanism is discussed. CPU microspheres are used as fluorescent probe to detect 4-nitrophenol (4-NP) based on their emission in UV light region, with excellent selectivity and sensitivity. In addition, they are reusable with detection limit unchanged after 7 cycles of reuses, a significant feature of this work. The mechanism of fluorescence detection is thoroughly explored and ascribed to the internal filtration effect. Based on the emission in visible light region, CPU microspheres are used as a model of PU microplastics (MPs) to visualize their biodistribution in HeLa and macrophage cells, as well as in zebrafish larvae, providing a reliable tracer for the visualization and tracking of PU MPs in organisms.

Rational design of diblock copolymer enables efficient cytosolic protein delivery

Polymer-mediated cytosolic protein delivery demonstrates a promising strategy for the development of protein therapeutics. Here, we propose a new designed diblock copolymer which realizes efficient cytosolic protein delivery both in vitro and in vivo. The polymer contains one protein-binding block composed of phenylboronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units for protein binding and endosomal escape, respectively, followed by the response to ATP enriched in the cytosol which triggers the protein release. The other block is PEG designed to improve particle size control and circulation in vivo. By optimizing the block composition, sequence and length of the copolymer, the optimal one (BP20) was identified with the binding block containing 20 units of both PBA and DMAP, randomly distributed along the chain. When mixed with proteins, the BP20 forms stable nanoparticles and mediates efficient cytosolic delivery of a wide range of proteins including enzymes, toxic proteins and CRISPR/Cas9 ribonucleoproteins (RNP), to various cell lines. The PEG block, especially when further modified with folic acid (FA), enables tumor-targeted delivery of Saporin in vivo, which significantly suppresses the tumor growth. Our results shall inspire the design of novel polymeric vehicles with robust capability for cytosolic protein delivery, which holds great potential for both biological research and therapeutic applications.

Correlation between existential form of ruthenium cocatalyst and photocatalytic hydrogen evolution of carbon nitride

Catalysts composed of nanocluster and single-atom (SA) were extensively used to enhance electrocatalytic water splitting performance, whereas study of their photocatalytic hydrogen (H2) evolution activity was limited. Herein, carbon nitride (CN) decorated by ruthenium (Ru) cocatalysts existed as SA + cluster, cluster + nanoparticles (NPs), and NPs were prepared by impregnation and calcination processes. The correlation between existential form, content of Ru cocatalyst and H2 evolution rate were carefully discussed. It was found that Ru NPs were favor for water molecule adsorption, whereas Ru SAs and clusters facilitated H2 desorption. Theoretical calculations revealed that Ru clusters + NPs cocatalyst were beneficial for H* intermediate formation. Water splitting tests found that 1.07 wt% Ru NPs + cluster modified CN showed the highest H2 evolution rate of 13.64 mmol h-1 g-1, which was 266.4 and 1.5 times higher than those of CN and Ru NPs (2.33 wt%) decorated CN, respectively. This work deeply reveals the influences of existential form of Ru cocatalysts on photocatalytic water splitting of CN, and provides thought in designing new cocatalysts to largely enhance H2 evolution.

CoS2/carbon network flexible film with Co-N bond/π-π interaction enables superior mechanical properties and high-rate sodium ion storage

Flexible electrodes based on conversion-type materials have potential applications in low-cost and high-performance flexible sodium-ion batteries (FSIBs), owing to their high theoretical capacity and appropriate sodiation potential. However, they suffer from flexible electrodes with poor mechanical properties and sluggish reaction kinetics. In this study, freestanding CoS2 nanoparticles coupled with graphene oxides and carbon nanotubes (CoS2/GO/CNTs) flexible films with robust and interconnected architectures were successfully synthesized. CoS2/GO/CNTs flexible film displays high electronic conductivity and superior mechanical properties (average tensile strength of 21.27 MPa and average toughness of 393.18 KJ m-3) owing to the defect bridge for electron transfer and the formation of the π-π interactions between CNTs and GO. In addition, the close contact between the CoS2 nanoparticles and carbon networks enabled by the Co-N chemical bond prevents the self-aggregation of the CoS2 nanoparticles. As a result, the CoS2/GO/CNTs flexible film delivered superior rate capability (213.5 mAh g-1 at 6 A g-1, better than most reported flexible anode) and long-term cycling stability. Moreover, the conversion reaction that occurred in the CoS2/GO/CNTs flexible film exhibited pseudocapacitive behavior. This study provides meaningful insights into the development of flexible electrodes with superior mechanical properties and electrochemical performance for energy storage.

Construction of coherent interface between Cu2O and CeO2via electrochemical reconstruction for efficient carbon dioxide reduction to methane

Developing an efficient electrocatalyst that enables the efficient electrochemical conversion from CO2 to CH4 across a wide potential range remains a formidable challenge. Herein, we introduce a precatalyst strategy that realizes the in situ electrochemical reconstruction of ultrafine Cu2O nanodomains, intricately coupled on the CeO2 surface (Cu2O/CeO2), originating from the heterointerface comprised of ultrafine CuO nanodomains on the CeO2 surface (CuO/CeO2). When served as the electrocatalyst for the electrochemical CO2 reduction reaction, Cu2O/CeO2 delivers a selectivity higher than 49 % towards CH4 over a broad potential range from -1.2 V to -1.7 V vs. RHE, maintaining negligible activity decay for 20 h. Notably, the highest selectivity for CH4 reaches an impressive 70 % at -1.5 V vs. RHE. Through the combination of comprehensive analysis including synchrotron X-ray absorption spectroscopy, spherical aberration-corrected high-angle annular dark field scanning transmission electron microscope as well as the density functional theoretical calculation, the efficient production of CH4 is attributed to the coherent interface between Cu2O and CeO2, which could converted from the original CuO and CeO2 interface, ensuring abundant active sites and enhanced intrinsic activity and selectivity towards CH4.