A multi-element flame retardant containing boron and double-bond structure for enhancing mechanical properties and flame retardancy of epoxy resins.

A multi-element synergistic flame retardant with double-bond structure was synthesized and added to epoxy resin (EP) to obtain EP composites with high flame retardant and mechanical properties. The study demonstrated that the DOPO-KhCPA-5 composite, containing 5 wt% of DOPO, exhibits the limiting oxygen index (LOI) value of 32%, indicating a high resistance to combustion. Additionally, it successfully meets the UL-94 V-0 grade, indicating excellent self-extinguishing properties. The DOPO-KhCPA-5 compound exhibited a 48.7% decrease in peak heat release rate (PHRR) and a 7.2% decrease in total heat release (THR) compared to pure EP. The inclusion of double-bonded architectures in the DOPO-KhCPA-5 composites led to a significant enhancement in both the tensile strength and tensile modulus. Specifically, the tensile strength increased by 38.5% and the tensile modulus by 57.9% compared to pure EP. This improvement can be attributed to the formation of a fully interpenetrating network of macromolecular chain structures by DOPO-KhCPA within the EP matrix. This network increased the entanglement between molecular chains, resulting in positive effects on the mechanical properties of the EP. Multi-element of DOPO-KhCPA exhibits a synergistic effect, providing condensed and noncombustible gas-phase flame retardancy. Additionally, the mechanical properties were improved with the introduction of flame retardants due to the good impact of double-bond cross-linking. The effectiveness of DOPO-KhCPA as an additive for developing high-performance EP with significant potential applications has been proven.

Electrochemical microfluidic sensing platforms for biosecurity analysis.

Biosecurity encompasses the health and safety of humans, animals, plants, and the environment. In this article, "biosecurity" is defined as encompassing the comprehensive aspects of human, animal, plant, and environmental safety. Reliable biosecurity testing technology is the key point for effectively assessing biosecurity risks and ensuring biosecurity. Therefore, it is crucial to develop excellent detection technologies to detect risk factors that can affect biosecurity. An electrochemical microfluidic biosensing platform integrates fluid control, target recognition, signal transduction, and output and incorporates the advantages of electrochemical analysis technology and microfluidic technology. Thus, an electrochemical microfluidic biosensing platform, characterized by exceptional analytical sensitivity, portability, rapid analysis speed, low reagent consumption, and low risk of contamination, shows considerable promise for biosecurity detection compared to traditional, more complex, and time-consuming detection technologies. This review provides a concise introduction to electrochemical microfluidic biosensors and biosecurity. It highlights recent research advances in utilizing electrochemical microfluidic biosensing platforms to assess biosecurity risk factors. It includes the use of electrochemical microfluidic biosensors for the detection of risk factors directly endangering biosecurity (direct application: namely, risk factors directly endangering the health of human, animals, and plants) and for the detection of risk factors indirectly endangering biosecurity (indirect application: namely, risk factors endangering the safety of food and the environment). Finally, we outline the current challenges and future perspectives of electrochemical microfluidic biosensing platforms.

Bioinspired Nanozymes as Nanodecoys for Urinary Tract Infection Treatment.

Urinary tract infections (UTIs), common bacterial infections in communities and medical facilities, are mainly mediated by FimH. The glycan sites of the uromodulin protein play a crucial role in protecting against UTIs by interacting with FimH. A bioinspired approach using glycan-FimH interactions may effectively reduce bacteria through an antiadhesive mechanism, thereby curbing bacterial resistance. However, typical antiadhesive therapy alone fails to address the excessive reactive oxygen species and inflammatory response during UTIs. To bridge this gap, antioxidant nanozymes with antiadhesive ability were developed as nanodecoys to counter bacteria and inflammation. Specifically, ultrasmall dextran-coated ceria (DEC) was engineered to address UTIs, with dextran blocking FimH adhesion and ceria exhibiting anti-inflammatory properties. DECs, metabolizable by the kidneys, reduced bacterial content in the urinary tract, mitigating inflammation and tissue damage. In murine models, DECs successfully treated acute UTIs, repeated infections, and catheter-related UTIs. This dual approach not only highlights the potential of nanozymes for UTIs but also suggests applicability to other FimH-induced infections in the lungs and bowels, marking a significant advancement in nanozyme-based clinical approaches.

A NAD(P)H oxidase mimic for catalytic tumor therapy via a deacetylase SIRT7-mediated AKT/GSK3ß pathway.

Nicotinamide adenine dinucleotide (NADH) and its phosphorylated form, NADPH, are essential cofactors that play critical roles in cell functions, influencing antioxidation, reductive biosynthesis, and cellular pathways involved in tumor cell apoptosis and tumorigenesis. However, the use of nanomaterials to consume NAD(P)H and thus bring an impact on signaling pathways in cancer treatment remains understudied. In this study, we employed a salt template method to synthesize a carbon-coated-cobalt composite (C@Co) nanozyme, which exhibited excellent NAD(P)H oxidase (NOX)-like activity and mimicked the reaction mechanism of natural NOX. The C@Co nanozyme efficiently consumed NAD(P)H within cancer cells, leading to increased production of reactive oxygen species (ROS) and a reduction in mitochondrial membrane potential. Meanwhile, the generation of the biologically active cofactor NAD(P)+ promoted the expression of the deacetylase SIRT7, which in turn inhibited the serine/threonine kinase AKT signaling pathway, ultimately promoting apoptosis. This work sheds light on the influence of nanozymes with NOX-like activity on cellular signaling pathways in tumor therapy and demonstrates their promising antitumor effects in a tumor xenograft mouse model. These findings contribute to a better understanding of NAD(P)H manipulation in cancer treatment and suggest the potential of nanozymes as a therapeutic strategy for cancer therapy.

Fluorophore and nanozyme-functionalized DNA walking: A dual-mode DNA logic biocomputing platform for microRNA sensing in clinical samples.

Inspired by the programmability and modifiability of nucleic acids, point-of-care (POC) diagnostics for nucleic acid target detection is evolving to become more diversified and intelligent. In this study, we introduce a fluorescent and photothermal dual-mode logic biosensing platform that integrates catalytic hairpin assembly (CHA), toehold-mediated stand displacement reaction (SDR) and a DNA walking machine. Dual identification and signal reporting modules are incorporated into DNA circuits, orchestrated by an AND Boolean logic gate operator and magnetic beads (MBs). In the presence of bispecific microRNAs (miRNAs), the AND logic gate activates, driving the DNA walking machine, and facilitating the collection of hairpin DNA stands modified with FAM fluorescent group and CeO2@Au nanoparticles. The CeO2@Au nanoparticles, served as a nanozyme, can oxidize TMB into oxidation TMB (TMBox), enabling a near-infrared (NIR) laser-driven photothermal effect following the magnetic separation of MBs. This versatile platform was employed to differentiate between plasma samples from breast cancer patients, lung cancer patients, and healthy donors. The thermometer-readout transducers, derived from the CeO2@Au@DNA complexes, provided reliable results, further corroborated by fluorescence assays, enhancing the confidence in the diagnostics compared to singular detection method. The dual-mode logic biosensor can be easily customized to various nucleic acid biomarkers and other POC signal readout modalities by adjusting recognition sequences and modification strategies, heralding a promising future in the development of intelligent, flexible diagnostics for POC testing.

Artificial enzyme innovations in electrochemical devices: advancing wearable and portable sensing technologies.

With the rapid evolution of sensing technologies, the integration of nanoscale catalysts, particularly those mimicking enzymatic functions, into electrochemical devices has surfaced as a pivotal advancement. These catalysts, dubbed artificial enzymes, embody a blend of heightened sensitivity, selectivity, and durability, laying the groundwork for innovative applications in real-time health monitoring and environmental detection. This minireview penetrates into the fundamental principles of electrochemical sensing, elucidating the unique attributes that establish artificial enzymes as foundational elements in this field. We spotlight a range of innovations where these catalysts have been proficiently incorporated into wearable and portable platforms. Navigating the pathway of amalgamating these nanoscale wonders into consumer-appealing devices presents a multitude of challenges; nevertheless, the progress made thus far signals a promising trajectory. As the intersection of materials science, biochemistry, and electronics progressively intensifies, a flourishing future seems imminent for artificial enzyme-infused electrochemical devices, with the potential to redefine the landscapes of wearable health diagnostics and portable sensing solutions.

Nanozyme-Cosmetic Contact Lenses for Ocular Surface Disease Prevention.

Efficiently balancing excess reactive oxygen species (ROS) caused by various factors on the ocular surface is a promising strategy for preventing the development of ocular surface diseases (OSDs). Nevertheless, the conventional topical administration of antioxidants is limited in efficacy due to poor absorption, rapid metabolism, and irreversible depletion, which impede their performance. To address this issue, contact lenses embedded with antioxidant nanozymes that can continuously scavenge ROS, thereby providing an excellent preventive effect against OSDs are developed. Specifically, Prussian blue family nanozymes are chosen based on their multiple antioxidant enzyme-like activities and excellent biocompatibility. The diverse range of colors made them promising candidates for the development of cosmetic contact lenses (CCLs) as a substitute for conventional pigments. The efficacy of nanozyme-CCLs is demonstrated in rabbits and rats exposed to a high risk of developing OSDs. These OSDs' prevention nanozyme-CCLs can pave the way for CCLs toward powerful wearable biomedical devices and provide novel strategies for the rational utilization of nanomaterials in clinical practice.

Recent advances in metal-family flame retardants: a review.

The use of polymer materials is inextricably linked to our manufacturing life. However, most of them are easily combusted in the air and the combustion process generates a large amount of toxic fumes and dangerous smoke. This can result in injuries and property damage, as well as limiting their use. It is essential to enhance the flame-retardant properties and smoke suppression performance by using multiple flame retardants. Metal-based flame retardants have a unique chemical composition. They are environmentally friendly flame retardants, which can impart good smoke suppression, flame retardancy to polymers and further reduce the production of toxic gases. The differences in the compounds formed between the transition metals and the main group metals make them act differently as flame retardants for polymers. As a result, this study presents the research progress and flame-retardant mechanism of flame-retardant polymers for flame retardants from different groups of metals in the periodic table of elements in a systematic manner. In view of the differences between the main group metals and transition metals, the mechanism of their application in flame retardant polymer materials is carefully detailed, as are their distinct advantages and disadvantages. And ultimately, prospects for the development of transition metals and main group metals are outlined. It is hoped that this paper will provide valuable references and insights for scholars in the field.

Integrated Cascade Nanozymes with Antisenescence Activities for Atherosclerosis Therapy.

Senescent cells are the critical drivers of atherosclerosis formation and maturation. Mitigating senescent cells holds promise for the treatment of atherosclerosis. In an atherosclerotic plaque microenvironment, senescent cells interact with reactive oxygen species (ROS), promoting the disease development. Here, we hypothesize that a cascade nanozyme with antisenescence and antioxidant activities can serve as an effective therapeutic for atherosclerosis. An integrated cascade nanozyme with superoxide dismutase- and glutathione peroxidase-like activities, named MSe1 , is developed in this work. The obtained cascade nanozyme can attenuate human umbilical vein endothelial cell (HUVEC) senescence by protecting DNA from damage. It significantly weakens inflammation in macrophages and HUVECs by eliminating overproduced intracellular ROS. Additionally, the MSe1 nanozyme effectively inhibits foam cell formation in macrophages and HUVECs by decreasing the internalization of oxidized low-density lipoprotein. After intravenous administration, the MSe1 nanozyme significantly inhibits the formation of atherosclerosis in apolipoprotein E-deficient (ApoE-/- ) mice by reducing oxidative stress and inflammation and then decreases the infiltration of inflammatory cells and senescent cells in atherosclerotic plaques. This study not only provides a cascade nanozyme but also suggests that the combination of antisenescence and antioxidative stress holds considerable promise for treating atherosclerosis.

A probiotic nanozyme hydrogel regulates vaginal microenvironment for Candida vaginitis therapy.

Molecular therapeutics are limited for Candida vaginitis because they damage normal cells and tissues of vagina, aggravating the imbalance of vaginal microbiota and increasing the recurrence. To tackle this limitation, through the combination of peroxidase-like rGO@FeS2 nanozymes [reduced graphene oxide (rGO)] with Lactobacillus-produced lactic acid and H2O2, a responsive hyaluronic acid (HA) hydrogel rGO@FeS2/Lactobacillus@HA (FeLab) is developed. FeLab has simultaneous anti-Candida albicans and vaginal microbiota-modulating activities. In particular, the hydroxyl radical produced from rGO@FeS2 nanozymes and Lactobacillus kills C. albicans isolated from clinical specimens without affecting Lactobacillus. In mice with Candida vaginitis, FeLab has obvious anti-C. albicans activity but hardly damages vaginal mucosa cells, which is beneficial to vaginal mucosa repair. Moreover, a higher proportion of Firmicutes (especially Lactobacillus) and a decrease in Proteobacteria reshape a healthy vaginal microbiota to reduce the recurrence. These results provide a combined therapeutic of nanozymes and probiotics with translational promise for Candida vaginitis therapy.

Fe3N-decorated porous carbon frameworks from wheat flour with dual enzyme-mimicking activities for organic pollutant degradation.

Organic pollutants produced during industrial production are putting more stress on natural water resources. It is a considerable challenge to realize water remediation from organic pollutants in a cost-effective way. Here, we report a feasible method to fabricate Fe3N-decorated porous carbon frameworks (F/M-Fe) by one-step pyrolysis of wheat flour, melamine and metal ions. The prepared F/M-Fe possessing intrinsic peroxidase (POD)- and catalase (CAT)-like activities could effectively remove organic pollutants, which could be deduced from the degradation of methylene blue trihydrate (MB), rhodamine B (RhB), and tetracycline (TC) as pollutant simulants, as well as excess H2O2 without consuming additional resources and energy. The degradation process was facilitated by the primary active intermediates of ˙OH and 1O2 in the catalytic pathway, with efficiencies of 95.8% for MB, 91.6% for RhB, and 92.3% for TC achieved within 10, 50, and 70 min, respectively. Thanks to the encouraging recycling behavior and well-conditioned tolerance, F/M-Fe shows satisfactory catalytic performance on a proof-of-concept filter-type device for MB degradation. In addition, F/M-Fe could reduce organic pollutants to a safe level, under which zebrafish can survive well, which exhibited the potential value of F/M-Fe in water remediation.

An Organometallic Flame Retardant Containing P/N/S-Cu2+ for Epoxy Resins with Reduced Fire Hazard and Smoke Toxicity.

Epoxy resins (EPs) have superior physical and chemical features and are used in a wide range of applications in everyday life and engineering. However, its poor flame-retardant performance has hindered its wide application. Over the past decades of extensive research, metal ions have received increasing attention for their highly effective smoke suppression properties. In this work, we used an "aldol-ammonia condensation" reaction to structure the Schiff base structure, together with grafting using the reactive group on 9,10-dihydro-9-oxa-10-phospha-10-oxide (DOPO). Then, Cu2+ was used to replace Na+ to obtain DCSA-Cu flame retardant with smoke suppression properties. Attractively, DOPO and Cu2+ can collaborate, thus effectively improving EP fire safety. At the same time, the addition of a double-bond initiator at low temperatures allows small molecules to form in situ macromolecular chains through the EP network, enhancing the tightness of the EP matrix. With the addition of 5 wt % flame retardant, the EP shows well-defined fire resistance, and the limiting oxygen index (LOI) reaches 36% with a significant reduction in the values of peak heat release (29.72%). In addition, the glass-transition temperature (Tg) of the samples with in situ formations of macromolecular chains was improved, and the physical properties of EP materials are also retained.

PGCLCs of human 45,XO reveal pathogenetic pathways of neurocognitive and psychosocial disorders.

BACKGROUND: Neurocognitive disorders and psychosocial difficulties are common in patients with Turner syndrome and multiple neurodegenerative diseases, yet there is no effective cure. Human primordial germ cells (hPGCs) are pluripotent germline stem cells in early embryo, which pass genetic information from one generation to the next, whereas all somatic cells will die along with the end of life. However, it is not known whether patient hPGCs with Turner syndrome contain information of neurocognitive and psychosocial illness. RESULTS: In this report, we used a high-density of culture system of embryoids derived from iPSCs of a patient with Turner syndrome to ask how pathogenetic pathways are associated with onset of neurocognitive and psychosocial disorders. The hPGC-Like Cells (hPGCLCs) were in vitro specified from iPSCs of 45,XO, 46,XX and 46,XY by the high-density induction of embryoids. Amazingly, we found that the specification process of the hPGCLCs in 45,XO, compared to those in 46,XX and 46,XY, enriched several common pathogenetic pathways regulating neurocognitive and psychosocial disorders, that shared among multiple neurodegenerative diseases and Turner syndrome. The downregulated chemical synaptic transmission pathways, including glutamatergic, GABAergic, and nicotine cholinergic synapses, indicated synaptic dysfunctions, while upregulated pathways that were associated with imbalance of mitochondrial respiratory chain complexes and apoptosis, may contribute to neuronal dysfunctions. Notably, downregulation of three types of ubiquitin ligases E1-E2-E3 and lysosome-associated sulfatases and RAB9A, owing to haploinsufficiency and parental preference of the X chromosome expression, indicated that two pathways of cellular degradation, lysosome and ubiquitin-proteasome, were impaired in the specification process of 45,XO hPGCLCs. This would lead to accumulation of undesired proteins and aggregates, which is a typically pathological hallmark in neurodegenerative diseases. CONCLUSIONS: Our data suggest that the specification process of the hPGCLCs in 45,XO, compared to those in 46,XX and 46,XY, enriched pathogenetic pathways that are associated with the onset of neurocognitive and psychosocial disorders.

An Efficient Cross-Linked Phosphorus-Free Flame Retardant for Epoxy Resins.

Epoxy resins (EPs) have been widely used due to their great physical and chemical properties, but their poor flame retardancy limits their further application. In this work, we synthesized a flame retardant containing nitrile groups and a double bond to improve the flame retardancy of EPs. In this way, multiple cross-linking reactions can occur in the EPs to confer better flame retardancy by a simple heat treatment. The UL-94 vertical combustion test, CCT, and limiting oxygen index (LOI) test were used to characterize the flame retardant properties of the cross-linked flame retardant; the results show that with the 10 wt % addition of cross-linked flame retardant, the thermosets can pass the UL-94 V-0 rating. Meanwhile, the contents reached 20 wt %, and the peak heat release rate decreased 40% compared with neat EP.

Porphyrin-Containing Metallacage with Precise Active Sites and Super Long-Term Stability as a Specific Peroxidase Mimic for Versatile Analyte Determination.

Inspired by the architecture of single-atom catalysts, where the monodispersed metal atoms are widely distributed but stabilized by various coordination circumstances, the biomimetic design and synthesis of metalloporphyrin-containing nanocages have been demonstrated in this study. The nanocages were fabricated through a coordination-driven self-assembly process, and the Mn(III) porphyrin-based one was found to have exclusively peroxidase-like activity at pH 6.0 with neither oxidase nor catalase-like activity under the routine conditions. Benefiting from this, we demonstrated the wide applicability and convenient usage of an Mn(III)-containing supramolecular nanocage (Mn-PC) in the one-step detection of H2O2, sarcosine, and glucose through various oxidase-involved reactions, with a satisfactory detection limit and eligible specificity. Real samples including H2O2 in lens care solution, sarcosine in human urine, and glucose in human serum were also assayed, showing an adequate recovery rate. Such a specific activity originates from the super-consistent microstructure of each catalytic unit, which means that the active site of manganese porphyrin was "protected" by the confinement of the nanocage. This also helps to sustain the super long-term activity even after 545 days of storage. Furthermore, the intrinsic electronic structure of the Mn(III)-containing supramolecular nanocage endows the ability in electrochemical detection of H2O2 and glucose. Our smart design toward the supramolecular nanocages with a defined structure and quantity contributes to the construction of the ingenious sensing platform and has guiding significance for architectural design of nanozymes.

Recent Advances in Stability Issues of Inorganic Solid Electrolytes and Composite Solid Electrolytes for All-Solid-State Batteries.

The development of solid-state batteries has become one of the most promising directions in rechargeable secondary batteries due to their considerable energy densities and favorable safety. However, solid-state batteries with higher energy density and more durable and stable cycle life should be developed for large-scale energy storage and adaption to the rapidly increasing lithium battery production and sales market. Although inorganic solid electrolytes (ISEs) and composite solid electrolytes (CSEs) are relatively advantageous solid-state electrolytes, they also face severe challenges. This review summarizes the main stability issues related to chemical, mechanical, thermal, and electrochemical aspects faced by ISEs and CSEs. The corresponding state-of-the-art improvement strategies have been proposed, including filling of modified particles, electrolyte pore adjustment, electrolyte internal structure arrangement, and interface modification.

A Dopamine-Enabled Universal Assay for Catalase and Catalase-Like Nanozymes.

Developing a universal strategy to measure catalase (CAT)/CAT-like activity, on one hand, overcomes limitations on current assays, such as moderate sensitivity and limited sample scope; on the other hand, facilitates insightful studies on applications of CAT and CAT-like nanozymes. Herein, the oxygen-sensitive and H2O2-inhibitory self-polymerization of dopamine (DA) was demonstrated as an activity indicator of CAT or CAT-like nanozymes, which monitors the catalytically generated O2 in a hypoxic environment. A typical assay for natural CAT was achieved under the optimized conditions. Moreover, this assay was suitable for diverse types of samples, ranging from nanozymes, animal tissues, to human saliva. By comparing the merits and limitations of common methods, this assay shows all-round advantages in sensitivity, specificity, and versatility, facilitating the formulation of measurement criteria and the development of potential standardized assays for CAT (or CAT-like nanozyme) activity.

A Valence-Engineered Self-Cascading Antioxidant Nanozyme for the Therapy of Inflammatory Bowel Disease.

Antioxidant treatment strategy by scavenging reactive oxygen species (ROS) is a highly effective disease treatment option. Nanozymes with multiple antioxidant activities can cope with the diverse ROS environment. However, lack of design strategies and limitation of negative correlation for nanozymes with multiple antioxidant activities hindered their development. To overcome these difficulties, here we used ZnMn2 O4 as a model to explore the role of Mn valency at the octahedral site via a valence-engineered strategy, and found that its multiple antioxidant activities are positively correlated with the content of Mn4+ . Therefore, through this strategy, a self-cascading antioxidant nanozyme LiMn2 O4 was constructed, and its efficacy was verified at the cellular level and in an inflammatory bowel disease model. This work not only provides guidance for the design of multiple antioxidant nanozymes, but also broadens the biomedical application potential of multiple antioxidant nanozymes.

Data-informed discovery of hydrolytic nanozymes.

Nanozyme is a collection of nanomaterials with enzyme-like activity but higher environmental tolerance and long-term stability than their natural counterparts. Improving the catalytic activity and expanding the category of nanozymes are prerequisites to complement or even supersede enzymes. However, the development of hydrolytic nanozymes is still challenged by diverse hydrolytic substrates and following complicated mechanisms. Here, two strategies are informed by data to screen and predict catalytic active sites of MOF (metal-organic framework) based hydrolytic nanozymes: (1) to increase the intrinsic activity by finely tuned Lewis acidity of the metal clusters; (2) to improve the density of active sites by shortening the length of ligands. Finally, as-obtained Ce-FMA-MOF-based hydrolytic nanozyme is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds, and even their mixture, biofilms. This work provides a rational methodology to design hydrolytic nanozyme, enriches the diversity of nanozymes, and potentially sheds light on future evolution of enzyme engineering.

Biochar Nanozyme from Silkworm Excrement for Scavenging Vapor-Phase Free Radicals in Cigarette Smoke.

Serious lung diseases and other health problems caused by tobacco consumption are becoming more and more prominent all over the world. Scavenging the excessive harmful free radicals in cigarette smoke is proven to be an effective method in reducing the above problems. Carbon-based nanozymes have been widely studied due to their ability of scavenging free radicals. Accordingly, the biochar derived from silkworm excrement was reported as a nanozyme with free radical scavenging ability. The biochar nanozyme calcination at 900 °C with better free radical scavenging abilities was loaded into commercial cigarette filters for the following free radical scavenging verification in tobacco smoke. Mouse model results reveal the lung tissue could be improved by the addition of biochar nanozyme. This work not only provides an effective approach to reduce the harm caused by tobacco but also provides potential applications to rationally realize low-cost, ease of production, and a wide variety of biochar sources.