The Quest for Two-Dimensional MBenes: From Structural Evolution to Solar-Driven Hybrid Systems for Water-Fuel-Energy Generation and Phototherapy.

The field of 2D materials has advanced significantly with the emergence of MBenes, a new material derived from the MAX phases family, a novel class of materials that originates from the MAX phases family. Herein, this article explores the unique characteristics and morphological variations of MBenes, offering a comprehensive overview of their structural evolution. First, the discussion explores the evolutionary period of 2D MBenes associated with the several techniques for synthesizing, modifying, and characterizing MBenes to tailor their structure and enhance their functionality. The focus then shifts to the defect chemistry of MBenes, electronic, catalytic, and photothermal properties which play a crucial role in designing multifunctional solar-driven hybrid systems. Second, the recent advancements and potentials of 2D MBenes in solar-driven hybrid systems e.g. photo-electro catalysis, hybrid solar evaporators for freshwater and thermoelectric generators, and phototherapy, emphasizing their crucial significance in tackling energy and environmental issues, are explored. The study further explores the fundamental principles that regulate the improved photocatalytic and photothermal characteristics of MBenes, highlighting their promise for effective utilization of solar energy and remediation of the environment. The study also thoroughly assesses MBenes' scalability, stability, and cost effectiveness in solar-driven systems. Current insights and future directions allow researchers to utilize MBenes for sustainable and varied applications. This review regarding MBenes will be valuable to early researchers intrigued with synthesizing and utilizing 2D materials for solar-powered water-energy-fuel and phototherapy systems.

Work Function Tuning of Carbon Electrode to Boost the Charge Extraction in Hole Transport Layer-Free Perovskite Solar Cells.

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF) of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

Ultrahighly Sensitive and Selective Glutathione Sensor Based on Carbon Dot-Functionalized Solution-Gate Graphene Transistor.

A new type of carbon dot (CD)-functionalized solution-gated graphene transistor (SGGT) sensor was designed and fabricated for the highly sensitive and highly selective detection of glutathione (GSH). The CDs were synthesized via a one-step hydrothermal method using DL-thioctic acid and triethylenetetramine (TETA) as sources of S, N, and C. The CDs have abundant amino and carboxyl groups and were used to modify the surface of the gate electrode of SGGT as probes for detecting GSH. Remarkably, the CDs-SGGT sensor exhibited excellent selectivity and ultrahigh sensitivity to GSH, with an ultralow limit of detection (LOD) of up to 10-19 M. To the best of our knowledge, the sensor outperforms previously reported systems. Moreover, the CDs-SGGT sensor shows rapid detection and good stability. More importantly, the detection of GSH in artificial serum samples was successfully demonstrated.

Selective leaching process for efficient and rapid recycling of spent lithium iron phosphate batteries.

With the continuous development of new energy vehicles, the number of decommissioned lithium iron phosphate (LiFePO4) batteries has been constantly increasing. Therefore, it is necessary to recover metal from spent LiFePO4 batteries due to the high potential for environmental protection and high resource value. In this study, sodium persulfate (Na2S2O8) was selected as the oxidant to regulate and control the oxidation state and proton activity of the leaching solution through its high oxidizing ability. Selective recovery of lithium from LiFePO4 batteries was achieved by oxidizing LiFePO4 to iron phosphate (FePO4) during the leaching process. This paper reports an extensive investigation of the effects of various factors, including the acid concentration, initial volume fraction of the oxidant, reaction temperature, solid-liquid ratio, and reaction time, on lithium leaching. Li+ reached a high leaching rate of 93.3% within 5 minutes even at a low concentration of sulphuric acid (H2SO4), and high-purity lithium carbonate (Li2CO3) was obtained through impurity removal and precipitation reactions. In addition, the leaching mechanism was analysed by both X-ray diffraction and X-ray photoelectron spectroscopy characterization. The results show that the obtained high lithium-ion (Li+) leaching efficiency and fast Li+ leaching time can be ascribed to the superior oxidizing properties of Na2S2O8 and the stability of the crystal structure of LiFePO4 during the oxidative leaching process. The adopted method has significant advantages in terms of safety, efficiency and environmental protection, which are conducive to the sustainable development of lithium batteries.

Ultrasensitive Label-Free DNA Detection Based on Solution-Gated Graphene Transistors Functionalized with Carbon Quantum Dots.

Developing highly sensitive, reliable, cost-effective label-free DNA biosensors is challenging with traditional fluorescence, electrochemical, and other techniques. Most conventional methods require labeling fluorescence, enzymes, or other complex modification. Herein, we fabricate carbon quantum dot (CQD)-functionalized solution-gated graphene transistors for highly sensitive label-free DNA detection. The CQDs are immobilized on the surface of the gate electrode through mercaptoacetic acid with the thiol group. A single-stranded DNA (ssDNA) probe is immobilized on CQDs by strong π-π interactions. The ssDNA probe can hybridize with the ssDNA target and form double-stranded DNA, which led to a shift of Dirac voltage and the channel current response. The limit of detection can reach 1 aM which is 2-5 orders of magnitude lower than those of other methods reported previously. The sensor also exhibits a good linear range from 1 aM to 0.1 nM and has good specificity. It can effectively distinguish one-base mismatched target DNA. The response time is about 326 s for the 1 aM target DNA molecules. This work provides good perspectives on the applications in biosensors.

Nitrogen and Sulfur Co-Doped Hierarchically Porous Carbon Nanotubes for Fast Potassium Ion Storage.

Exploration of advanced carbon anode material is the key to circumventing the sluggish kinetics and poor rate capability for potassium ion storage. Herein, a synergistic synthetic strategy of engineering both surface and structure is adopted to design N, S co-doped carbon nanotubes (NS-CNTs). The as-designed NS-CNTs exhibit unique features of defective carbon surface, hollow tubular channel, and enlarged interlayer space. These features significantly contribute to a large potassium storage capacity of 307 mA h g-1 at 1 A g-1 and a remarkable rate performance with a capacity of 151 mA h g-1 even at 5 A g-1 . Furthermore, an excellent cyclability with 98% capacity retention after 500 cycles at 2 A g-1 is also achieved. Systematic analysis by in situ Raman spectroscopy and ex situ TEM demonstrates the structural stability and reversibility in the charge-discharge process. Although the kinetics studies reveal the capacitive-dominated process for potassium storage, density functional theory calculations provide evidence that N, S co-doping contributes to expanding the interlayer space to promote the K-ion insertion, improving the electronic conductivity, and providing ample defective sites to favor the K-ion adsorption.

Construction of highly efficient carbon dots-based polymer photonic luminescent solar concentrators with sandwich structure.

The enhancement of photoluminescence (PL) emission and waveguide play a key role in improving the optical efficiency of luminescent solar concentrators (LSCs). In this work, to boosting PL emission and waveguide simultaneously, one photonic crystal (PC) structure (crystalline colloid arrays (CCAs)) was introduced into carbon dots (CDs)-based polymer LSCs. A sandwich-structured CDs-based polymer photonic LSC, comprising glass/CDs-based polymer PC film/glass, was created. First, CDs-based colloidal crystal suspensions were prepared by co-assembly of monodispersed p(MMA-NIPAm) colloids and multicolor-emitting CDs in HEMA monomer induced by the evaporation-driven assembly. The obtained suspensions not only had uniform PL and structural colors, but showed enhanced PL emission. Second, the above suspensions were sandwiched between two glass sheets and finally a photonic polymer LSC with sandwiched structure (25 × 25 × 1.8 mm3) were formed via one-step photopolymerization technique. Remarkably, the optimal CDs-based polymer photonic LSCs with sandwiched structure not only had high transparence at visible range (>60%), but exhibited PL emission enhancement (at least 2 times). Furthermore, the maximum external optical efficiency (ηopt) of 5.84% could be achieved based on yellow-emitting CDs-based polymer photonic LSC. The high external optical efficiency was mainly attributed to the PL emission enhancement and good PC waveguide.

The recent progress on metal-organic frameworks for phototherapy.

Some infectious or malignant diseases such as cancers are seriously threatening the health of human beings all over the world. The commonly used antibiotic therapy cannot effectively treat these diseases within a short time, and also bring about adverse effects such as drug resistance and immune system damage during long-term systemic treatment. Phototherapy is an emerging antibiotic-free strategy to treat these diseases. Upon light irradiation, phototherapeutic agents can generate cytotoxic reactive oxygen species (ROS) or induce a temperature increase, which leads to the death of targeted cells. These two kinds of killing strategies are referred to as photodynamic therapy (PDT) and photothermal therapy (PTT), respectively. So far, many photo-responsive agents have been developed. Among them, the metal-organic framework (MOF) is becoming one of the most promising photo-responsive materials because its structure and chemical compositions can be easily modulated to achieve specific functions. MOFs can have intrinsic photodynamic or photothermal ability under the rational design of MOF construction, or serve as the carrier of therapeutic agents, owing to its tunable porosity. MOFs also provide feasibility for various combined therapies and targeting methods, which improves the efficiency of phototherapy. In this review, we firstly investigated the principles of phototherapy, and comprehensively summarized recent advances of MOF in PDT, PTT and synergistic therapy, from construction to modification. We expect that our demonstration will shed light on the future development of this field, and bring it one step closer to clinical trials.

[Effect of Gegen Qinlian Decoction on cardiac diastolic function of diabetic mice with damp-heat syndrome].

This study was designed to explore the effect and mechanism of Gegen Qinlian Decoction(GQD) on cardiac function of diabetic mice with damp-heat syndrome. The db/db diabetic mice were exposed to the damp-heat environment test chamber for inducing the damp-heat syndrome. Forty-eight six-week-old db/db mice were randomly divided into six groups, namely the db/db diabetic model group, db/db diabetic mouse with damp-heat syndrome(db/db-dh) group, db/db diabetic mouse with damp-heat syndrome treated with low-dose GQD(db/db-dh+GQD-L) group, db/db-dh+GQD-M(medium-dose) group, db/db-dh+GQD-H(high-dose) group, and db/db-dh+lipro(liprostatin-1, the inhibitor of ferroptosis) group, with eight six-week-old db/m mice classified into the control group. The results showed that mice presented with the damp-heat syndrome after exposure to the "high-fat diet" and "damp-heat environment", manifested as the elevated fasting blood glucose, reduced food intake, low urine output, diarrhea, listlessness, loose and coarse hair, and dark yellow and lusterless fur. However, the intragastric administration of the high-dose GQD for 10 weeks ameliorated the above-mentioned symptoms, inhibited myocardial hypertrophy and fibrosis, and improved the cardiac diastolic function of db/db-dh mice. qPCR suggested that GQD regulated the expression of ferroptosis-related genes, weakened the lipid peroxidation in the myocardium, and up-regulated glutathione peroxidase 4(GPX4) expression in comparison with those in the db/db-dh group. At the same time, the ferroptosis inhibitor liprostatin-1 significantly improved the cardiac function and reversed the cardiac remodeling of db/db-dh mice. It can be concluded that the damp-heat syndrome may aggravate myocardial ferroptosis and accelerate cardiac remodeling of db/db mice, thus leading to diastolic dysfunction. GQD is able to improve cardiac remodeling and diastolic function in diabetic mice with damp-heat syndrome, which may be related to its inhibition of myocardial ferroptosis.

Non-invasive detection of glucose via a solution-gated graphene transistor.

Owing to its high sensitivity, a solution-gated graphene transistor has rapidly emerged as a cutting edge technology in electrochemical sensing. In this work, composites of gold nanoparticles and reduced graphene oxide were synthesized on a glassy carbon electrode by using the electrodeposition method. A modified glassy carbon electrode was used as the gate electrode and assembled into the solution-gated graphene transistor device along with the graphene channel for a non-invasive glucose detection. The sensing mechanism was based on the change in current in the channel of the device caused by the addition of glucose, of which electro-oxidation on the surface of the gold nanoparticles and reduced graphene oxide led to a change in equivalent gate voltage, and consequently, affected the channel carrier concentration. The self-amplification effect of transistors was utilized in our sensors, which resulted in a detection limit that was 10 times lower than those of conventional electrochemical sensors. Compared to traditional enzymatic transistor sensors, the novel solution-gated graphene transistor nonenzymatic sensors based on gold nanoparticles and reduced graphene oxide demonstrated significant sensing advantages, such as a simple structure, wide linear range from 10 µM to 400 µM and 400 µM to 31 mM, and low detection limit down to 4 µM. The chemicals coexisting in human sweat e.g. sodium chloride, urea, and lactic acid imposed no distinct interference for the glucose detection. Therefore, we achieved a non-invasive detection of glucose in the artificial sweat samples with satisfactory sensing results. This work demonstrates an effective route for non-invasive glucose testing in practical clinical diagnosis by using nonenzymatic, solution-gated graphene transistor devices.

Heat shock protein 70: A promising therapeutic target for myocardial ischemia-reperfusion injury.

Acute myocardial infarction is a major cause of death worldwide. The most important therapy for limiting ischemic injury and infarct size is timely and efficient myocardial reperfusion treatment, which may instead induce cardiomyocyte necrosis due to myocardial ischemia-reperfusion (I/R) injury. Heat shock protein 70 (HSP70), a stress-inducible protein, is overexpressed during myocardial I/R. The induced HSP70 is shown to regulate several intracellular proteins (e.g., transcription factors, enzymes, and apoptosis-related proteins) and signaling pathways (e.g., c-Jun N-terminal kinase pathway and extracellular-signal-regulated kinase 1/2 pathway), forming a complicated network that contributes to reducing reactive oxygen species accumulation, improving calcium homeostasis, inhibiting cellular apoptosis, thereby enhancing the stress adaption of myocardium to I/R injury. In addition, the extracellular HSP70, which is released from injured cardiomyocytes during I/R, acts as a proinflammatory mediator that results in cell death, while the intracellular HSP70 exerts antiinflammatory effects by suppressing proinflammatory signaling pathways. Notably, HSP70 is induced and contributes to the cardioprotection in several types of preconditioning and postconditioning. Meanwhile, it is shown that the cardioprotective effectiveness of preconditioning-induced HSP70 (e.g., hyperthermia preconditioning-induced HSP70) can be impaired by certain pathological conditions, such as hyperlipidemia and hyperglycemia. Thus, we highlight the widespread cardioprotective involvement of HSP70 in preconditioning and postconditioning and elucidate how HSP70-mediated cardioprotection is impaired in these pathological conditions. Furthermore, several therapeutic potentials of HSP70 against myocardial I/R injury and potential directions for future studies are also provided in this review.

Rapid and Superior Bacteria Killing of Carbon Quantum Dots/ZnO Decorated Injectable Folic Acid-Conjugated PDA Hydrogel through Dual-Light Triggered ROS and Membrane Permeability.

One of the most difficult challenges in the biomedical field is bacterial infection, which causes tremendous harm to human health. In this work, an injectable hydrogel is synthesized through rapid assembly of dopamine (DA) and folic acid (FA) cross-linked by transition metal ions (TMIs, i.e., Zn2+ ), which was named as DFT-hydrogel. Both the two carboxyl groups in the FA molecule and catechol in polydopamine (PDA) easily chelates Zn2+ to form metal-ligand coordination, thereby allowing this injectable hydrogel to match the shapes of wounds. In addition, PDA in the hydrogel coated around carbon quantum dot-decorated ZnO (C/ZnO) nanoparticles (NPs) to rapidly generate reactive oxygen species (ROS) and heat under illumination with 660 and 808 nm light, endows this hybrid hydrogel with great antibacterial efficacy against Staphylococcus aureus (S. aureus, typical Gram-positive bacteria) and Escherichia coli (E. coli, typical Gram-negative bacteria). The antibacterial efficacy of the prepared DFT-C/ZnO-hydrogel against S. aureus and E. coli under dual-light irradiation is 99.9%. Importantly, the hydrogels release zinc ions over 12 days, resulting in a sustained antimicrobial effect and promoted fibroblast growth. Thus, this hybrid hydrogel exhibits great potential for the reconstruction of bacteria-infected tissues, especially exposed wounds.

Carbon dot-based inverse opal hydrogels with photoluminescence: dual-mode sensing of solvents and metal ions.

A dual-mode sensing platform, involving fluorescence and reflectance modes, has been demonstrated for highly sensitive and selective detection of solvents and metal ions based on carbon dot-based inverse opal hydrogels (CD-IOHs). In this work, CD-IOHs have been first synthesized via the typical templating technique. Two kinds of CDs, including solvent and Cu(ii) ion sensitive CDs, have been incorporated into the matrix of IOHs during the co-polymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA). The CD-IOHs not only appear green under daylight but also exhibit stable photoluminescence (PL) under UV light owing to the stop-band effect of photonic crystals and the quantum effect of CDs, respectively. By using these two optical phenomena, for solvent sensing, the CD-IOHs change their colors from green, yellow, and red to a semitransparent state and show good linear sensing with the ethanol content varying from 0 to 45% in reflectance mode, while their PL intensities exhibit a nonlinear detection trend: first an increase and then a decrease with the ethanol content in fluorescence mode. Remarkably, as for metal ion sensing, the CD-IOHs have high selectivity for Cu(ii) ions via the specific PL quenching effect of Cu(ii) ion sensitive CDs. Furthermore, the CD-IOHs show good linear detection in both modes and a wide linear detection range from 0.1 µM to 7 mM. Thus, high selectivity, colorimetric detection, a broad linear detection range, and dual-mode sensing can be realized using the CD-IOHs.

MicroRNA-449a Inhibition Protects H9C2 Cells Against Hypoxia/Reoxygenation-Induced Injury by Targeting the Notch-1 Signaling Pathway.

BACKGROUND/AIMS: The present study aimed to detect the expression of miR-449a and investigate the effect of miR-449a on cell injury in cardiomyocytes subjected to hypoxia/ reoxygenation (H/R) and its underlying mechanisms. METHODS: The expression of miR-449a was determined using reverse transcription-polymerase chain reaction in both neonatal rat ventricular myocytes and H9C2 cells. For gain-of-function and loss-of-function studies, H9C2 cells were transfected with either miR-449a mimics or miR-449a inhibitor. The target gene of miR-449a was confirmed by a dual-luciferase reporter assay. Apoptosis was analyzed by both flow cytometry using Annexin V and propidium iodide and transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL). Necrosis was confirmed by the detection of lactate dehydrogenase release. The cell viability was measured using the methylthiotetrazole method. The protein levels of Notch-1, Notch-1 intracellular domain, hairy and enhancer of split-1 (Hes-1), and apoptosis-related genes were measured by Western blot analysis. RESULTS: MiR-449a was significantly upregulated in both neonatal rat ventricular myocytes and H9C2 cells subjected to H/R. However, H/R-induced cell apoptosis and necrosis were markedly reduced by miR-449a inhibition. By targeting Notch-1, miR-449a regulated the Notch-1/ Hes-1 signaling pathway. The blockade of the Notch signaling pathway partly abolished the protective effect of miR-449a suppression against H/R injury, whereas the overexpression of Notch-1 intracellular domain partly reversed the effect of miR-449a overexpression on H/R-induced cell injury. CONCLUSIONS: The present study suggested that miR-449a inhibition protected H9C2 cells against H/R-induced cell injury by targeting the Notch-1 signaling pathway, providing a novel insight into the molecular basis of myocardial ischemia-reperfusion injury and a potential therapeutic target.

Gastrodin pretreatment alleviates myocardial ischemia/reperfusion injury through promoting autophagic flux.

Gastrodin (GAS), a monomeric component exacted from the herb Gastrodia elata Bl, may have cardioprotective effects during injury caused by myocardial ischemia/reperfusion (I/R). For the significant role of autophagy in I/R process, we targeted to explore whether autophagy was contributing to the GAS-induced protective effects during I/R procedure. Male C57BL/6 mice were subjected to reversible left coronary artery ligation and cultured neonatal rat cardiomyocytes (NRCs) exposed to hypoxia were preconditioned with GAS prior to ischemia or hypoxia, following reperfusion for 2 h or re-oxygennation for 3 h respectively. Our results demonstrated that GAS pretreatment increased autophagy and reduced apoptosis during I/R, this effect was weakened by co-treatment with the autophagic flux inhibitor chloroquine (Cq). Compared to mice subjected solely to I/R, GAS-pretreated mice had a notably smaller heart infarct size and an elevation in cardiac function. In GAS-pretreated NRCs, WB data showed that autophagy was promoted (expression of p62 was inhibited and LC3II was increased). In addition, tandem fluorescent mRFP-GFP-LC3 assays illustrated that autophagosomes were degraded duo to an increase in autophagic flux. Co-administration of Cq blocked the autophagic flux. Furthermore, GAS pretreatment increased the mitochondrial membrane potential of NRCs with subjected to H/R and increased the cardiomyocyte survival rate. These protective effects were reversed with Cq. Besides, GAS-induced the enhaucement of autophagy may correlated with activating AMP-activated protein kinase (AMPK) phosphorylation and reduced Mammalian target of rapamycin (mTOR) phosphorylation, which was abrogated by Compound C (Com C, AMPK-specific inhibitor). Our results establish that GAS pretreatment attenuates myocardial I/R injury by increasing autophagic flux aimed at eliminating dysfunctional mitochondria, therefore protecting neighbouring mitochondria and cardiomyocytes.

In Situ Disinfection through Photoinspired Radical Oxygen Species Storage and Thermal-Triggered Release from Black Phosphorous with Strengthened Chemical Stability.

Photodynamic therapy (PDT) utilizing light-induced reactive oxygen species (ROS) is a promising alternative to combat antibiotic-resistant bacteria and biofilm. However, the photosensitizer (PS)-modified surface only exhibits antibacterial properties in the presence of light. It is known that extended photoirradiation may lead to phototoxicity and tissue hypoxia, which greatly limits PDT efficiency, while ambient pathogens also have the opportunity to attach to biorelevant surfaces in medical facilities without light. Here, an antimicrobial film composed of black phosphorus nanosheets (BPSs) and poly (4-pyridonemethylstyrene) endoperoxide (PPMS-EPO) to control the storage and release of ROS reversibly is introduced. BPS, as a biocompatible PS, can produce high singlet oxygen under the irradiation of visible light of 660 nm, which can be stably stored in PPMS-EPO. The ROS can be gradually thermally released in the dark. In vitro antibacterial studies demonstrate that the PPMS-EPO/BPS film exhibits a rapid disinfection ability with antibacterial rate of 99.3% against Escherichia coli and 99.2% against Staphylococcus aureus after 10 min of irradiation. Even without light, the corresponding antibacterial rate reaches 76.5% and 69.7%, respectively. In addition, incorporating PPMS significantly improves the chemical stability of the BPS.

Polyethylene Glycol Based Graphene Aerogel Confined Phase Change Materials with High Thermal Stability.

Polyethylene glycol (PEG) based graphene aerogel (GA) confined shaped-stabilized phase change materials (PCMs) are simply prepared by a one-step hydrothermal method. Three-dimensional GA inserted by PEG molecule chains, as a supporting material, obtained by reducing graphene oxide sheets, is used to keep their stabilized shape during a phase change process. The volume of GA is obviously expended after adding PEG, and only 9.8 wt% of GA make the composite achieve high energy efficiency without leakage during their phase change because of hydrogen bonding widely existing in the GA/PEG composites (GA-PCMs). The heat storage energy of GA-PCMs is 164.9 J/g, which is 90.2% of the phase change enthalpy of pure PEG. In addition, this composite inherits the natural thermal properties of graphene and thus shows enhanced thermal conductivity compared with pure PEG. This novel study provides an efficient way to fabricate shape-stabilized PCMs with a high content of PEG for thermal energy storage.

Green emitting N,S-co-doped carbon dots for sensitive fluorometric determination of Fe(III) and Ag(I) ions, and as a solvatochromic probe.

N,S-co-doped carbon dots (N,S-CDs) were synthesized via a single-step solvothermal process by using sodium lignosulfonate and p-phenylenediamine as carbon/nitrogen/sulfur sources. The N,S-CDs have an average diameter of 2.02 ± 1 nm and display green fluorescence, with excitation/emission peak wavelengths at 380/540 nm for optimal fluorescence. Fluorescence is excitation wavelength-dependent and stable in aqueous salt solutions. The fluorescence of the N,S-CDs is selectively quenched by Fe(III) and Ag(I) ions. These ions can be quantified by fluorometry with a limit of detection of 1.7 µM for Fe(III) ions and 11.6 µM for Ag(I) ions. The N,S-CDs also undergo solvatochromism in that emission is green in water solution but blue in polar organic solvents such as ethanol or N,N-dimethylformamide. The color of fluorescence gradually shifts from green to blue when continuously increasing the fraction of organic solvent in water. Graphical abstract N,S-co-doped carbon dots (N,S-CDs) are synthesized by using sodium lignosulfonate and p-phenylenediamine as C/N/S sources. The N,S-CDs can sensitively detect Fe(III) and Ag(I) ions based on fluorometry, and can be used as a solvatochromic probe.

Urolithin A alleviates myocardial ischemia/reperfusion injury via PI3K/Akt pathway.

Ischemia/reperfusion (I/R) induces additional damage to the restoration of blood flow to ischemic myocardium. This study examined the effects of urolithin A (UA) on myocardial injury of ischemia/reperfusion in vivo and vitro and explored its underlying mechanisms. Mice were subjected to myocardial ischemia followed by reperfusion. Cells were subjected to hypoxia followed by reoxygenation. UA alleviated hypoxia/reoxygenation (H/R) injury in myocardial cells, reduced myocardial infarct size and cell death in mice after ischemia/reperfusion. Meanwhile, UA enhanced antioxidant capacity in cardiomyocytes following hypoxia/reoxygenation. UA reduced myocardial apoptosis following ischemia/reperfusion. The protection of UA was abolished by LY294002, a PI3K/Akt-inhibitor. These results demonstrated that UA alleviates myocardial ischemia/reperfusion injury probably through PI3K/Akt pathway.

Trimetazidine Protects Cardiomyocytes Against Hypoxia/Reoxygenation Injury by Promoting AMP-activated Protein Kinase-dependent Autophagic Flux.

Trimetazidine (TMZ), a metabolic agent, may protect against myocardial ischemia/reperfusion injury. Because of the critical role of autophagy in cardioprotection, we aimed to evaluate whether autophagy was involved in TMZ-induced protection during hypoxia/reoxygenation (H/R). Neonatal rat cardiomyocytes were subjected to H/R injury, and they were divided into 7 groups: control, control+TMZ, control+chloroquine (Cq)/compound C (com C), H/R, H/R+TMZ, H/R+Cq/com C, and H/R+TMZ+Cq/com C. Autophagic flux was primarily assessed by Western blot and tandem fluorescent mRFP-GFP-LC3. Assays for MTS, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and lactate dehydrogenase release were performed to assess cell injury. Our results showed that TMZ pretreatment had a cardioprotective effect against H/R injury. The H/R+TMZ group had an increased ratio of LC3-II to LC3-I and increased autophagic flux (degradation of p62 and increases in autophagosomes and autolysosomes). TMZ also reduced apoptosis and enhanced cell survival while inducing autophagy. Correspondingly, autophagy inhibition with Cq blocked this protective effect. Furthermore, TMZ-induced enhancement of autophagy could be related to increased AMP-activated protein kinase (AMPK) phosphorylation and decreased Mammalian target of rapamycin (mTOR) phosphorylation, which was abolished by an AMPK-specific inhibitor (com C). Our data provide evidence that TMZ pretreatment protects against H/R injury by promoting autophagic flux through the AMPK signaling pathway.