Excess Oxygen Research Articles

Bioactive Nanoparticle-Embedded Micro/Nanofibrous Dressing with Improved Angiogenesis and Immunoregulation for Facilitating Burn Wound Healing.

In the context of severe burn injuries, the presence of excessive reactive oxygen species (ROS), prolonged microbial infection, and compromised angiogenesis can contribute to the metabolic reprogramming of macrophages, resulting in a dysregulated inflammatory response that hinders the healing process. In this study, cerium oxide nanoparticles (CeNPs) are encapsulated within a silk fibroin-poly(e-caprolactone) polymer to create an electrospun PSF/CeNPs nanofiber membrane (PSF/membrane). This membrane is further modified through the addition of an angiopoietin-1 mimetic peptide, QHREDGS, resulting in the formation of QPSF/CeNPs (QHREDGS modified PSF/CeNPs membrane). In vitro assessments revealed that the QPSF/CeNPs displayed the intended ability to regulate ROS levels, favorable biocompatibility with cells, promoted endothelial cell attachment and growth, exhibited anti-inflammatory properties through the modulation of macrophage phenotypes from M1 to M2, as well as pro-angiogenetic and antibacterial effects. In vivo, the membrane dressing demonstrated an acceleration of burn wound healing, promotion of angiogenesis, downregulation of inflammatory factors, and enhancement of collagen deposition. This bioactive membrane dressing shows potential as a clinical therapy for promoting the regeneration of both acute and chronically damaged skin tissue.

Newcastle disease virus infection induces parthanatos in tumor cells via calcium waves

Parthanatos is distinct from caspase-dependent apoptosis in that it does not necessitate the activation of caspase cascades; Instead, it relies on the translocation of Apoptosis-inducing Factor (AIF) from the mitochondria to the nucleus, resulting in nuclear DNA fragmentation. Newcastle Disease Virus (NDV) is an oncolytic virus that selectively targets and kills tumor cells by inducing cell apoptosis. It has been reported that NDV triggers classic apoptosis through the mitochondrial pathway. In this study, we observed that NDV infection induced endoplasmic reticulum stress (ERS), which caused a rapid release of endogenous calcium ions (Ca2+). This cascade of events resulted in mitochondrial depolarization, loss of mitochondrial membrane potential, and structural remodeling of the mitochondria. The overload of Ca2+ also initiated an increase in mitochondrial membrane permeability, facilitating the transfer of AIF to the nucleus to induce apoptosis. Damaged mitochondria produced excessive reactive oxygen species (ROS), which further exacerbated mitochondrial damage and increased mitochondrial membrane permeability, thus promoting additional intracellular Ca2+ accumulation and ultimately triggering an ROS burst. Collectively, these findings indicate that NDV infection promotes excessive calcium accumulation and ROS generation, leading to mitochondrial damage that releases more calcium and ROS, creating a feedback loop that exacerbates AIF-dependent parthanatos. This study not only provides a novel perspective on the oncolytic mechanism of NDV but also highlights new targets for antiviral research.

Injectable Multifunctional Hyaluronan based Hydrogel Suppressing the Excessive Glucose and Reactive Oxygen Species in Diabetic Wound Treatment

In diabetic wounds, the overlapping presence of excessive glucose and reactive oxygen species (ROS) forming a vicious cycle that severely impedes the wound healing process. Despite advancements in wound care, current treatments often limit in addressing these two critical factors simultaneously. To address these challenges, this study introduces a multifunctional hydrogel system capable of dual regulation of excessive glucose and ROS levels in a hyperglycemic environment, while also provide a platform with favorable properties that support wound healing. First, by modifying hyaluronic acid (HA) chains with vinyl sulfone and thiol functional groups, the resulting hydrogel exhibited tunable gelation time, elastic modulus, and degradation rates, making it adaptable for diabetic wound management. Notably, this hydrogel allows for precise glucose and ROS regulation by encapsulating glucose oxidase (GOx), horseradish peroxidase (HRP), and tannic acid (TA) within the HA hydrogel matrix. It was verified that the hydrogels could reduce the glucose levels to desired concentration by varying the encapsulated GOx content. Simultaneously, the combined ROS-scavenging effect of HRP and TA effectively addressed the excessive ROS problem. Specifically, H2O2 generated from the GOx-glucose reaction was consumed in the HRP-mediated polymerization of TA, and free radicals (OH•, DPPH) were scavenged up to 70% by TA. Due to the glucose and ROS regulation properties, this hydrogel system was able to promote the proliferation and migration of human dermal fibroblast in a hyperglycemic environment. Overall, this study offers a simple and effective approach to regulate the excessive levels of glucose and ROS in a hyperglycemic condition, which has potential in creating a multifunctional platform for diabetic wound treatment.

Dual-metal synergy unlocking ROS-free catalysis for rapid aerobic oxidation of 5-hydroxymethylfurfural at room temperature

Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields. However, unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive oxygen species (ROS). Herein, we reported a new ROS-free approach to effectively drive O2 to be activated into highly reactive surface peroxo species through enzyme-mimicking mechanism. Benefiting from the dual-metal synergy effect between Cu and Co active sites, ROS (H2O2 and OH•) is generated in situ while further scavenged completely into surface peroxo species, which gives rise to very high selectivity and extremely high carbon balance. For example, the CuCo/N-C catalyst affords >99.8% conversion and 94.5% selectivity to 2,5-furanedicarboxylic acid at 25 °C for 6 h in the aerobic oxidation of biomass platform 5-hydroxymethylfurfural. Moreover, it achieved exceptional performance in the oxidation of a variety of hydroxyl compounds to organic acids with high yields (89.9%–99.5%) at a mild temperature (25–40 °C). This exploration introduces an innovative clue for emulating enzyme catalysts, thereby enriching our comprehension and advancement of biologically inspired catalytic oxidations.

Molecular identification and characterization of the superoxide dismutase (SOD) gene family in Tetranychus urticae (Acari: Tetranychidae) and the role of TuSOD2 gene under short-term heat stress

Superoxide dismutases (SODs) are key enzymes for scavenging insects' excess reactive oxygen species (ROS) and play a crucial role in resisting a variety of stresses. The deletion of SOD genes can alter the response of insects to abiotic stresses. In this study, four genes of the superoxide dismutase family in Tetranychus urticae were identified and analyzed, among which three copper/zinc SODs and a manganese SOD. The result of quantitative real-time PCR showed that TuSOD2 expression level was up-regulated significantly under short-term heat stress, but TuSOD1, TuSOD2, and TuSOD4 were down-regulated or no significant difference, which indicated that T. urticae responded to oxidative stress induced by heat stress by raising the expression level of superoxide dismutase gene. Among them, TuSOD2 gene plays a key role in response to heat stress in T. urticae, and other SOD genes may be responsible for other oxidative stresses. RNA interference experiments showed that the knocking down of TuSOD2 reduced the activities of various antioxidant enzymes, resulting in a decline in the tolerance to high temperature and an increase in the mortality of T. urticae under short-term heat stress. To summarize, SOD, especially TuSOD2 plays an important role in treating short-term heat stress in T. urticae.

A pH-responsive copper selenide nanozyme modulates multiple enzyme activities for improved healing of infected wounds

Bacterial infections can slow down wound healing and pose a threat to human health, which remains a challenging issue in clinical practice. The rise of nanozymes has provided new therapeutic approaches for antimicrobial treatment. Here, we report pH-responsive copper selenide nanoparticles (Cu1.79Se, hereafter referred to as CuSe), which exhibits peroxidase (POD)-like activity under weakly acid bacterial infection conditions, generating highly reactive hydroxyl radicals (·OH) that kill bacteria and alleviate wound infections. In the later stages of wound healing, it is neutral or weakly alkaline, the CuSe nanoparticles shows catalase (CAT) and superoxide dismutase (SOD)-like activities, clearing excessive reactive oxygen species (ROS) and producing O2, thus protecting normal tissues from damage caused by both external and endogenous ROS. The above feature helps damaged tissue cells regain their ability to proliferate and migrate, also promotes angiogenesis, achieving a "two birds with one stone" effect. It is expected that the CuSe nanoparticles could be a promising antimicrobial agent for wound healing.

Halobenzoquinone-induced potential carcinogenicity associated with p53-mediated cell cycle pathway

2,6-Dibromo-1,4-benzoquinone (2,6-DBBQ) and 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), two emerging halobenzoquinones (HBQs), have the highest detection frequencies and levels in drinking water among all HBQs. They are more toxic than the regulated disinfection byproducts. Quantitative structure toxicity relationship analysis predicted that HBQs are a class of potential bladder carcinogens. However, direct experimental evidence for the carcinogenicity of 2,6-DBBQ and 2,6-DCBQ is lacking and the associated toxicity mechanisms remain unclear. In this study, we confirmed the potential carcinogenicity of 2,6-DBBQ and 2,6-DCBQ using an in vitro malignant transformation assay, evaluated their cytotoxicity and genotoxicity, and investigated their toxicity mechanisms. The results showed that 2,6-DBBQ and 2,6-DCBQ significantly decreased the viability of human uroepithelial SV-HUC-1 cells and induced DNA damage in SV-HUC-1 cells, and chromosomal damage in HepG2 cells, and malignant transformation of SV-HUC-1 cells. Moreover, transcriptome sequencing revealed that 2,6-DBBQ and 2,6-DCBQ activated the p53-mediated cell cycle pathway in bladder cancer. In the p53-mediated cell cycle pathway, 2,6-DBBQ and 2,6-DCBQ induced cell cycle arrest at the S phase by downregulating p53 and upregulating p21. Additionally, 2,6-DBBQ and 2,6-DCBQ may have produced excessive reactive oxygen species, damaging DNA and chromosomes. These results not only first confirm the potential carcinogenicity of 2,6-DBBQ and 2,6-DCBQ but also provide an important reference for exploring the cytotoxicity and genotoxicity mechanisms of these HBQs.

Lattice energy transfer from homo-crystalline substitution for enhanced piezo-photocatalytic CO2 conversion

The rapid recombination of carriers and large activation energy of CO2 compromise the efficiency of CO2 photoreduction. Herein, SrTiO3 (STO) with different molar ratios of La3+ and Al3+ double-site homo-crystalline substitution is prepared by a ball-milling molten salt method. The concentration of Ti3+ and excess oxygen vacancies decrease to improve the catalytic activity. Meanwhile, the double sites act as electron transfer platforms for easy electron transfer from the bulk phase to the surface to foster CO2 photoreduction. Not only that, the energy transfer due to doping-induced lattice distortion can potentially enhance the photocatalytic activity. A piezoelectrically polarized electric field is introduced to further expedite charge transport. As a result, the activity of La, Al-STO piezo-photocatalytic CO2 reduction is improved to 39.17 µmol g-1h−1, which is more than seven times better than that of the pure STO. Furthermore, CO2 adsorbs spontaneously on the catalysts because the thermodynamic energy barrier decreases due to the piezoelectric force, which is verified by density-functional theory calculation. This study reveals the great potential of double-site homo-crystalline substitution of STO pertaining to the charge transport kinetics and thermodynamics of the catalytic reaction in the piezo-photocatalytic CO2 process.

Raffinose Priming Improves Seed Vigor by ROS Scavenging, RAFS, and α-GAL Activity in Aged Waxy Corn

Raffinose family oligosaccharides (RFOs) are known to benefit plants under stress conditions; however, the role of exogenous raffinose in seed germination remains poorly understood. In this study, we investigated the potential role of raffinose in promoting seed germination and elucidated the underlying mechanisms. The results showed that artificial aging significantly reduced the germination rate and vigor of waxy corn seeds. Conversely, exogenous raffinose significantly enhanced the germination of these artificially aged seeds. Exogenous raffinose significantly reduced the levels of reactive oxygen species (O2− and H2O2) and enhanced the activity of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Additionally, the levels of α-galactosidase (α-GAL) and raffinose synthase (RAFS) were significantly elevated in raffinose-treated aged seeds. These findings suggest that exogenous raffinose induces the expression of α-GAL and RAFS, thereby providing energy and reducing excessive reactive oxygen species (ROS), which in turn promotes the germination of artificially aged seeds. This study provides a theoretical foundation for enhancing seed vigor and extending seed longevity in crop management.

Supramolecular Assembly‐Enabled Transdermal Therapy of Hypertrophic Scarring Through Concurrent Ferroptosis‐Apoptosis

AbstractHypertrophic scar (HS) remains a major challenge for clinicians due to unsatisfactory therapeutic performance. Although inducing apoptosis of HS fibroblasts (HSFs) has proved to be an effective nonsurgical treatment strategy, potential chemotherapy resistance to apoptosis of HSFs makes the development of new and efficient strategies highly demanding. Herein, a ferroptosis‐apoptosis combined therapeutic strategy for the treatment of HS is developed through supramolecular self‐assembly between cucurbit[7]uril (CB[7]) and two bioactive agents, dihydroartemisinin (DHA) and gold nanoclusters (AuNCs). The resulting self‐assembled supramolecular nanoparticles, named CAD NPs, showed high guest loading efficiency and prominent pH‐responsive degradability in the acidic lysosomes of HSFs. Importantly, both DHA and AuNCs act synergistically to generate excessive reactive oxygen species and lipid peroxidation, leading to mitochondrial damage, and ultimately inducing concurrent ferroptosis and apoptosis on HSFs. Upon further loading into hydrogel microneedles to facilitate their transdermal delivery, these CAD NPs showed superior antiscar therapeutic effects in shortening the treatment span to 3 weeks and improving the HS appearance, as demonstrated at a rabbit ear model of HS. The present supramolecular assembly‐based ferroptosis‐apoptosis strategy provides an innovative guideline for efficiently treating HS as well as other diseases.

Amylopectin from maize-derived carbonized polymer dots as a novel high-efficiency antioxidant for periodontitis treatment

Periodontitis is a common chronic inflammatory disease and the local accumulation of excessive reactive oxygen species (ROS) could cause oxidative damage to periodontal tissues. Thus, antioxidative therapy is considered to be the promising strategy for treating periodontitis. However, highly efficient antioxidant activity of biomaterials with low cost, ease of synthesis, and good biocompatibility are still highly desired. Here amylopectin from maize (AFM)-derived carbonized polymer dots (AFM-CPDs-240) with excellent antioxidant activity, good water solubility and biosafty is parepared. Detailed characterizations identify that the antioxidant properties and formation mechanism of AFM-CPDs, and antioxidant activity of AFM-CPDs-240 is much higher than Trolox (a hydrophilic derivative of vitamin E) due to the large contents of conjugated C=C and C=O. Besides, in vitro and in vivo experiments suggest AFM-CPDs-240 could effectively alleviate inflammatory response, inhibit alveolar bone resorption and promote bone formation, showing excellent therapeutic effects on periodontitis. Moreover, the label-free proteomics and western blot results demonstrate AFM-CPDs-240 could accelerate the recovery of periodontitis by blocking TLR4/NF-κB (Toll-like receptor 4/ nuclear factor-kappa B) signaling pathway. This study will develop a simple approach to design highly efficient antioxidant carbon dots with good biocompatibility, and also provide a new promising nanoplatform for treating diseases associated with ROS.

An Asymmetric Bacterial Cellulose Membrane Incorporating CuPt Nanozymes and Curcumin for Accelerating Wound Healing.

Damaged skin compromises its ability to effectively prevent the invasion of harmful bacteria into the tissue, leading to bacterial infection of the wound and hindering the healing process. To address this challenge, we have developed a multifunctional asymmetric wound dressing (CuPt-Cur-ABC) that effectively addresses the lack of bactericidal activity and the release of active ingredients in conventional bacterial cellulose (BC), which can be employed to create a barrier of defense between the wound and its surrounding environment. Compared with BC, asymmetric bacterial cellulose (ABC) used starch as a pore-causing agent, forming holes of different sizes at the top and bottom, which enhanced the ability of ABC to load and moderate-release drugs. First, as-synthesized CuPt nanozymes with an octopod nanoframe structure had multiple enzymatic activities including peroxidase-like, catalase-like, and glutathione peroxidase-like activities. Then, CuPt and curcumin (Cur) were loaded into ABC under ultrasound. Under 808 nm laser irradiation, the nanocomposites possessed good photothermal properties. So the photothermal therapy combined with chemodynamic therapy and inherent antibacterial performance of Cur achieved 99.3% and 99.6% in vitro bactericidal efficacy against Staphylococcus aureus and Escherichia coli, respectively. Moderate release of Cur can clear the excess reactive oxygen species and promote the polarization of macrophages toward the M2 type. In vivo experiments additionally confirmed that the constructed wound dressing achieved multiple functions, including effective antibacterial activity, reversing the inflammatory microenvironment, and promoting wound healing.

Inflammatory Microenvironment‐Responsive Nanomotors with NIR Photothermal Effect for Deep Inflammation Elimination and Infection Inhibition

AbstractThe infected chronic wound area has a unique microenvironment featuring hypoxia, excessive reactive oxygen species (ROS), and inflammatory conditions. Bacteria‐formed biofilms limit the anti‐inflammation efficiency of most therapeutics by hindering their penetration into deep infected wound tissues and increasing drug resistance. The unitary modulation of pro‐inflammatory M1 macrophage polarization cannot relieve inflammation immediately. Here, the “all in one” folic acid‐modified small organic molecule‐based nanoparticles (2TT‐mC6B@CeO2@FA, PCFs) are developed, which possess dual‐targeting to bacteria and M1 macrophages, double modulation to M1 macrophages, photothermal therapy (PTT), and enzymatic‐like activities. Based on the considerable catalase‐ and superoxide dismutase‐like activities, PCFs can efficiently scavenge ROS and produce oxygen (O2). The generated O2 can automatically drive PCFs movement as nanomotors to further promote deep penetration and rescue hypoxia. The scavenging of ROS promotes M1 macrophages polarized into anti‐inflammatory M2 macrophages. The study also identifies that FA‐modified PCFs can target bacteria and M1 macrophages to selectively eliminate M1 macrophages and bacteria through PTT, which relieves inflammation and chronic wound healing. Transcriptome analysis confirms that PCFs inhibit the expression of inflammatory‐related genes while increasing the expression of anti‐inflammatory cytokines. In vivo experiments identify that PCFs benefit neovascularization in neonatal tissues and tissue generation at wound sites.

Pyrroloquinoline-quinone supplementation restores ovarian function and oocyte quality in a mouse model of advanced maternal age.

Natural ovarian aging is one of the major causes for declining fertility in female animals, which has become an insurmountable issue in human reproduction clinics and assisted reproductive technology (ART) procedures. Nevertheless, the molecular basis of oocyte aging remains poorly understood, and feasible improvement strategies are unavailable. In the present study in vivo supplementation of pyrroloquinoline-quinone (PQQ) effectively elevated the fecundity of reproductively aged mice by balancing hormonal secretion, harmonizing the estrus cycle, and eliminating ovarian fibrosis. Moreover, oocyte quality also increased in aged mice after PQQ administration from various aspects, including nuclear and cytoplasmic maturation competency, fertilization capacity and pre-implantation embryonic development potential. Transcriptomic analysis identified target pathways that might mediate PQQ's effects in aged oocytes. Specifically, it was demonstrated that PQQ supplementation restored the mitochondrial dynamics and lysosomal function to remove excessive reactive oxygen species (ROS) and suppress apoptosis in aged oocytes. Jointly, these findings demonstrate PQQ administration is an efficacious method to restore the compromised ovary function and damaged oocyte quality in reproductively aged mice, which might be a potential clinical therapy for women of advanced maternal age with infertility.

Oxide-nitride nanolayer stacks for enhanced passivation of p-type surfaces in silicon solar cells

In the quest for ultra-high-efficiency silicon solar cells, optimising surface passivation has emerged as a critical pathway to minimise losses and enhance device performance. Recent breakthroughs in aluminium oxide (AlOx) passivation show an interface to Si with low interface defect density and high negative charge density after activation annealing at 400–450 °C, enabling low surface recombination velocities. The formation of an interfacial SiOx layer has been recognised as a key factor. In this study, we present an in-depth investigation of a SiOx/AlOx/SiNx nanolayer stack interface with Si, where the SiOx is wet chemically grown. By varying the AlOx deposition from 5 to 40 ALD cycles, we observed a reduction in interface defect density, indicating the presence of negatively charged hydrogen in the AlOx layer. We reveal a distinctly different interface between Si and nanolayer stacks with or without AlOx. Activation annealing significantly reduced recombination losses for stacks with AlOx, attributed to increased charge density and decreased carrier capture velocity at the valence band-tail. We find lower electron capture rates in nanolayer stacks containing AlOx, suggesting effective passivation of donor states by negatively charged hydrogen. Additionally, the formation of new acceptor states was detected by an increase in hole capture velocity at the interface after annealing. Electron energy loss spectroscopy (EELS) identified an Al:SiOxNy layer of ∼2.5 nm thick with excess oxygen content and a mixture of tetrahedral and octahedral coordinated Al, likely contributing to the formation of acceptor defects and suggest an intrinsic link between the chemical and field-effect passivation.

Molecular Roles of NADPH Oxidase-Mediated Oxidative Stress in Alzheimer's Disease: Isoform-Specific Contributions.

Oxidative stress is linked to the pathogenesis of Alzheimer's disease (AD), a neurodegenerative disorder marked by memory impairment and cognitive decline. AD is characterized by the accumulation of amyloid-beta (Aβ) plaques and the formation of neurofibrillary tangles (NFTs) of hyperphosphorylated tau. AD is associated with an imbalance in redox states and excessive reactive oxygen species (ROS). Recent studies report that NADPH oxidase (NOX) enzymes are significant contributors to ROS generation in neurodegenerative diseases, including AD. NOX-derived ROS aggravates oxidative stress and neuroinflammation during AD. In this review, we provide the potential role of all NOX isoforms in AD pathogenesis and their respective structural involvement in AD progression, highlighting NOX enzymes as a strategic therapeutic target. A comprehensive understanding of NOX isoforms and their inhibitors could provide valuable insights into AD pathology and aid in the development of targeted treatments for AD.

Dual-Sliding-Surface Robust Control for the PEMFC Air-Feeding System Based on Terminal Sliding Mode Algorithm

The proton exchange membrane fuel cell (PEMFC) is the most widely used fuel cell, but it also has some limitations. One of the research pain points is controlling the oxygen content in PEMFCs. A moderate excess of oxygen boosts electrochemical reaction efficiency, while an appropriate oxygen content ensures system stability. In this paper, a fourth-order nonlinear mathematical model of a PEMFC stack air supply system is established to solve the problem of optimal oxygen excess ratio (OER) control under dynamic load conditions. Based on the model, a nonsingular terminal sliding mode controller (NTSMC) based on a sliding mode observer (SMO) is proposed. The NTSM exhibits superior robustness and performance compared to other sliding mode structures. Meanwhile, the SMO accurately predicts system states, facilitating precise control actions. Additionally, the dual sliding mode surfaces enhance system stability against parameter uncertainties and external disturbances. Our results demonstrate that the proposed controller outperforms traditional ones in terms of robustness and performance, which significantly enhances PEMFC system efficiency and stability.

Oxide-Perovskites for Automotive Catalysts Biotransform and Induce Multicomponent Clearance and Hazard.

Oxide-perovskites designed for automotive catalysts contain multiple metal elements whose presence is crucial to achieving the targeted performance. They are highly stable in exhaust operating conditions; however, little is known about their stability under physiological conditions. As some of the metallic components are hazardous to humans and the environment, perovskite benefits in cleaner air must be balanced with risks in a Safe and Sustainable Design (SSbD) approach. New approach methodologies (NAMs), including in chemico and in silico methods, were used for testing hazards and benefits, including catalytic activity and tolerance for temporary excess of oxygen under dynamic driving conditions. The composition and surface properties of six different lanthanum-based oxide-perovskites compromised their stability under lung physiological conditions, influencing the oxidative damage of the particles and the bioacessibility of leaching metals. We found consistent biotransformation of the oxide-perovskite materials at pH 4.5. The leached lanthanum ions, but not other metals, respeciated into lanthanum phosphate nanoparticles, which increased the overall oxidative damage in additive synergy. The NAM results in the presented SSbD approach were challenged by in vivo studies in rats and mice, which confirmed multicomponent clearance from lungs into urine and supported the comparative ranking of effects against well-characterized spinel materials. Among the perovskites, the version with reduced nickel content and doped with palladium offered the best SSbD balance, despite not improving the conventional benchmark catalytic performance and related sustainability benefits. Redesign by industry may be necessary to better fulfill all SSbD dimensions.

Lattice sulfuration enhanced sodium storage performance of Na0.9Li0.1Zn0.05Ni0.25Mn0.6O2 cathode

Introducing lattice oxygen redox for charge compensation in layered metal oxides is an effective way to develop advanced cathodes for high energy density sodium-ion batteries (SIBs). However, the asymmetry of lattice oxygen oxidation and reduction incurs oxygen release and crystal structure rearrangement, leading to poor reversibility of the charge and discharge process. Herein, a Na2S-assisted sulfuration strategy is firstly proposed to incorporate active sulfur into the crystal lattice of Na0.9Li0.1Zn0.05Ni0.25Mn0.6O2 cathode. The sulfur anions within the interior lattice participate in the redox process and enhance the integral coordination stability by mitigating undesired excessive oxygen redox, while the exterior sulfur forms a polyanionic layer to protect the particle surface against electrolyte corrosion. The incorporation of an extra redox center efficiently facilitates the increase of the discharge capacity from 159.9 to 179.2 mAh g−1 within the voltage range of 1.5–4.5 V. Moreover, the larger ionic radius of sulfur enlarges the interplanar spacing, thus facilitating Na+ ions transfer, especially at high current density. As a result, the modified cathode exhibits significantly enhanced electrochemical performance, with a capacity retention of 87 % after 100 cycles at 0.2 C and an excellent rate capability of 98.0 mAh g−1 at 10 C. Moreover, the assembled Na ion full cell based on a commercial hard carbon anode achieves an impressive capacity of 160.4 mAh g−1 at 0.1 C and could cycled steadily for over 100 cycles. The modification of layer oxides via sulfuration strategy provides a promising pathway for the structural design of novel cathodes with superior cycle performance for high-energy-density SIBs applications.

Potential of epicatechin as antioxidant and antiaging in UV-induced BJ cells by regulating COL1A1, FGF-2, GPX-1, and MMP-1 gene, protein levels, and apoptosis

Background Oxidative stress caused by exposure to ultraviolet (UV) light on the skin can damage deoxyribonucleic acid (DNA) and cause keratinocytes to undergo apoptosis. Endogenous antioxidants which play a role in trapping free radicals are also unable to overcome excess reactive oxygen species (ROS) in the body due to UV exposure, so exogenous antioxidants are needed. Polyphenolic compounds extracted from natural ingredients such as flavonoids, quercetin, and epicatechin have quite strong antioxidant activity. This is influenced by the chemical structure of these compounds which are rich in hydroxyl groups and aromatic groups. This structure allows the compound to become an electron donor so that it can neutralize free radicals. In vitro research was used to see the potential effectiveness of epicatechin as an antiaging and antioxidant. The study aims to confirm the potential of epicatechin as an antiaging by in vitro assay. Methods The viability test of epicatechin on human skin fibroblast (BJ) cells was carried out using the water-soluble tetrazolium (WST) assay. BJ cells were UV-induced as a cell model of premature aging. Epicatechin 6.25, 12.5, and 25 µg/mL were administered to UV-induced BJ cells. The gene expression of Collagen I Alpha 1 (COL1A1), matrix metalloproteinase-1 (MMP-1), fibroblast growth factor-2 (FGF-2), and glutathione peroxidase-1 (GPX-1) were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Elastin (ELN), hyaluronidase (HAase), cyclooxigenase-2 (COX-2), 8-hydroxydeoxyguanosine (8-OhdG), and melatonin (MT) protein levels were analyzed by enzyme-linked immunosorbent assay (ELISA). The apoptosis of BJ cells was analyzed using flow cytometry. Results Treatment with epicatechin increased relative gene expression including COL1A1 (5.94), FGF-2 (8.34), and GPX-1 (8.09), and also decreased MMP-1 (2.90) relative gene expression compared to the UV-induced BJ cells. Epicatechin also increased levels of ELN (107.7 ng/mg protein) and MT (830 ng/mg protein) levels compared to the UV-induced BJ cells. Epicatechin treatment decreased levels of HAase (505.96 ng/mg protein), COX-2 (33.69 ng/mg protein), and 8-OHdG (97.87 ng/mg protein) compared to the UV-induced BJ cells. Epicatechin also succeeded in maintaining the percentage of live cells and reducing apoptosis, necrotic of UV-induced skin fibroblast cells. Conclusions Epicatechin has the potential to be an antiaging agent by in vitro assay.