Methamphetamine induces cardiomyopathy through GATA4/NF-κB/SASP axis-mediated cellular senescence.

With the world pandemic of methamphetamine (METH), METH-associated cardiomyopathy (MAC) has become a widespread epidemic and is also recognized as a cause of heart failure in young people. The mechanism of occurrence and development of MAC is not clear. In this study, firstly, the animal model was evaluated by echocardiography and myocardial pathological staining. The results revealed that the animal model exhibited cardiac injury consistent with clinical alterations of MAC, and the mice developed cardiac hypertrophy and fibrosis remodeling, which led to systolic dysfunction and left ventricular ejection fraction (%LVEF) < 40%. The expression of cellular senescence marker proteins (p16 and p21) and senescence-associated secretory phenotype (SASP) was significantly increased in mouse myocardial tissue. Secondly, mRNA sequencing analysis of cardiac tissues revealed the key molecule GATA4, and Western blot, qPCR and immunofluorescence results showed that the expression level of GATA4 was significantly increased after METH exposure. Finally, knockdown of GATA4 expression in H9C2 cells in vitro significantly attenuated METH-induced cardiomyocyte senescence. Consequently, METH causes cardiomyopathy through cellular senescence mediated by the GATA4/NF-κB/SASP axis, which is a feasible target for the treatment of MAC.

Ultrasensitive and Visual Electrochemiluminescence Ratiometry Based on a Constant Resistor-Integrated Bipolar Electrode for MicroRNA Detection.

In this work, a new electrochemiluminescence (ECL) platform was constructed for detecting the prostate cancer marker microRNA-141 (miRNA-141) on a constant resistor-integrated closed bipolar electrode (BPE). It consisted of two reservoirs and a constant resistor, and both ends were connected to the anode of the driving electrode and the cathode of BPE. The cathode of BPE was modified with boron nitride quantum dots (BNQDs), and the anode reservoir was the [Ru(bpy)3](PF6)2/TPrA system. After introducing a certain amount of hairpin DNA 3 (H3) and ferrocene-labeled single-stranded DNA (Fc-ssDNA) on the surface of the BNQDs, the ECL emission signal of the BNQDs was difficult to be observed by the naked eye, while [Ru(bpy)3](PF6)2 emitted a strong and visible ECL signal. In the presence of the target, bipedal DNA assembled by catalytic hairpin assembly (CHA) took away the Fc-ssDNA and the ECL intensity of the BNQDs was enlarged, and as the concentration of miRNA-141 increased to the cutoff value, yellow-green light was visible by the naked eye. Meanwhile, the red emission signal of [Ru(bpy)3](PF6)2/TPrA became weakened. Thus, an ultrasensitive "color switch" ECL biosensor for detection of miRNA-141 was constructed and endowed with a wide linear range from 10-17 to 10-7 M and a detection limit of 10-17 M (S/N = 3). This study provides the potential for investigating portable devices in the detection of low-concentration nucleic acids.

New insight into methamphetamine-associated heart failure revealed by transcriptomic analyses: Circadian rhythm disorder.

Methamphetamine (METH) abuse is a significant public health concern globally. Cardiac toxicity is one of the important characteristics of METH, in addition to its effects on the nervous system. However, to date, research on the cardiotoxic injury induced by METH consumption has been insufficient. To systematically analyze the potential molecular mechanism of cardiac toxicity in METH-associated heart failure (HF), a rat model was constructed with a dose of 10 mg/kg of METH consumption. Cardiac function was evaluated by echocardiography, and HE staining was used to clarify the myocardial histopathological changes. Integrated analyses, including mRNA, miRNA and lncRNA, was performed to analyze the RNA expression profile and the potential molecular mechanisms involved in METH-associated HF. The results showed that METH caused decreased myocardial contractility, with a decreased percent ejection fraction (%EF). Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses of the RNAs with expression changes revealed abnormal circadian rhythm regulation in the METH groups, with circadian rhythm-related genes and their downstream effectors expressed differentially, especially the aryl hydrocarbon receptor nuclear translocator-like (Arntl). Competing endogenous RNA (ceRNA) networks associated with circadian rhythm, including Arntl, was also observed. Therefore, this study revealed that long-term METH consumption was associated with the HF in a rat model by decreasing the %EF, and that the abnormal circadian rhythm could provide new directions for investigating the METH-associated HF, and that the differentially expressed genes in this model could provide candidate genes for the identification and assessment of cardiac toxicity in METH-associated HF, which is fundamental for further understanding of the disease.

Methamphetamine exposure induces neuronal programmed necrosis by activating the receptor-interacting protein kinase 3 -related signalling pathway.

Methamphetamine (METH) is a synthetic drug with severe neurotoxicity, however, the regulation of METH-induced neuronal programmed necrosis remains poorly understood. The aim of this study was to identify the molecular mechanisms of METH-induced neuronal programmed necrosis. We found that neuronal programmed necrosis occurred in the striatum of brain samples from human and mice that were exposed to METH. The receptor-interacting protein kinase 3 (RIP3) was highly expressed in the neurons of human and mice exposed to METH, and RIP3-silenced or RIP1-inhibited protected neurons developed neuronal programmed necrosis in vitro and in vivo following METH exposure. Moreover, the RIP1-RIP3 complex causes cell programmed necrosis by regulating mixed lineage kinase domain-like protein (MLKL)-mediated cell membrane rupture and dynamin-related protein 1 (Drp1)-mediated mitochondrial fission. Together, these data indicate that RIP3 plays an indispensable role in the mechanism of METH-induced neuronal programmed necrosis, which may represent a potential therapeutic target for METH-induced neurotoxicity.

Amino-functionalized NH2-MIL-125(Ti)-decorated hierarchical flowerlike Znln2S4 for boosted visible-light photocatalytic degradation.

Developing novel heterojunction photocatalysts with visible-light response and remarkable photocatalytic activity have been verified to applying for the photodegradation of antibiotics in water environment. Herein, NH2-MIL-125(Ti) was integrated with flowerlike ZnIn2S4 to construct NH2-MIL-125(Ti)@ZnIn2S4 heterostructure using a one-pot solvothermal method. The photocatalytic performance was evaluated by the degradation of tetracycline (TC) under visible light illumination. The optimized NM(2%)@ZIS possesses a photodegradation rate (92.8%) and TOC removal efficiency (58.5%) superior to pristine components, which can be principally attributed to the positive cooperative effects of well-matched energy level positions, strong visible-light-harvesting capacity, and abundant coupling interfaces between the two. Moreover, the probable TC degradation mechanism was also clarified using the active species trapping experiments. This study inspires further design and construction of NH2-MIL-125(Ti) and ZnIn2S4 based photocatalysts for effective removal of antibiotics in water environment.

Transcriptomic Changes of Astrocytes in the Brain of Rats with Subacute METH Exposure.

OBJECTIVES: To study the transcriptomic changes of astrocytes in the brain of rats exposed to methamphetamine (METH) and its possible mechanism in neurotoxicity. METHODS: The rats were intraperitoneally injected with METH (15 mg/kg) every 12 h for 8 times in total to establish the subacute rat model of METH. After the model was successfully established, the striatum was extracted, and astrocytes were separated by the magnetic bead method. Transcriptome sequencing was performed on selected astrocytes, and the differentially expressed genes were analyzed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. RESULTS: A total of 876 differentially expressed genes were obtained by transcriptome sequencing, including 321 up-regulated genes and 555 down-regulated genes. GO analysis revealed that differentially expressed genes were mainly concentrated in cell structure, biological process regulation, extracellular matrix and organelle functions. KEGG pathway enrichment analysis showed that steroids biosynthesis, fatty acid biosynthesis, peroxisome proliferators-activated receptor (PPAR), adenosine 5'-monophosphate-activated protein kinase (AMPK) and other signaling pathways were significantly changed. CONCLUSIONS: METH can cause structural changes of astrocytes through multiple targets, among which cellular structure, steroids biosynthesis and fatty acid biosynthesis may play an important role in nerve injury, providing a new idea for forensic identification of METH related death.

Enhancement of the energy resolution of CsI(Na) scintillators by photonic crystals prepared with dry-transfer technique.

Photonic crystals coated on the surface of scintillators can be used to improve the light extraction efficiency by partially eliminating the total internal reflection. However, the traditional self-assembly technique is not applicable to the hygroscopic scintillators. In the present investigation, we have proposed an efficient method to prepare the photonic crystals on the surface of CsI(Na) hygroscopic scintillators by a combination of the self-assemble of polystyrene (PS) microspheres and the subsequent dry-transfer procedure. For obtaining optimal parameters of photonic crystals, the light output of the CsI(Na) sample is enhanced by 43.2% compared to the reference sample without photonic crystals under the excitation of alpha particles from 241Am source. The energy resolution is improved from 11.2% to 7.8%. This technique based on the dry-transfer procedure has a promising prospect in the preparation of photonic crystals for hygroscopic scintillators.

Fluorometric determination of zinc(II) by using DNAzyme-modified magnetic microbeads.

A fluorometric assay for zinc ion is described that relies (a) on the use of an isothermal cycle to amplify the fluorescence signal, and (b) of magnetic beads (MBs) to completely remove unreacted DNA detection probes. Biotin and fluorophore-labeled substrate (Zn-Sub) strands acting as detection probes were first assembled on MBs. Next, Zn(II)-specific DNAzyme (Zn-Enz) strands were hybridized with the Zn-Sub strands. In the presence of Zn(II), the Zn-Sub strands are cleaved. This results in the release of the shorter DNA fragments (containing fluorescent label) and in the dissociation of Zn-Enz strands. The dissociated Zn-Enz strands then hybridize with the residual Zn-Sub strands and cleave them in a similar fashion. This leads to a target recycling amplification mechanism and in a cumulative signal amplification process. A strongly amplified signal is thus obtained in the presence of Zn(II). The use of MBs warrants that unreacted Zn-Sub strands can be magnetically separated from the solution. The method has a detection limit as low as 33 fM at a signal-to-noise ratio of 3 and a linear response in the 100 fM to 11 nM Zn(II) concentration range. It was applied to the determination of Zn(II) in spiked tap water and seawater samples, and the results compared well with data obtained by ICP-MS analysis. The method was also applied to the determination of Zn(II) in infant milk powder and breast milk. Graphical abstract Magnetic beads (MBs) carrying fluorescein-labeled substrate (Zn-Sub) strands were hybridized with Zn(II)-specific DNAzyme (Zn-Enz) and cleaved in the presence of Zn(II). After recycling, the unreacted Zn-Sub strands were removed with MBs and the released fluorescein tags are measured.

DNA damage-inducible transcript 4 (DDIT4) mediates methamphetamine-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes.

Methamphetamine (METH) is an amphetamine-like psychostimulant that is commonly abused. Previous studies have shown that METH can induce damages to the nervous system and recent studies suggest that METH can also cause adverse and potentially lethal effects on the cardiovascular system. Recently, we demonstrated that DNA damage-inducible transcript 4 (DDIT4) regulates METH-induced neurotoxicity. However, the role of DDIT4 in METH-induced cardiotoxicity remains unknown. We hypothesized that DDIT4 may mediate METH-induced autophagy and apoptosis in cardiomyocytes. To test the hypothesis, we examined DDIT4 protein expression in cardiomyocytes and in heart tissues of rats exposed to METH with Western blotting. We also determined the effects on METH-induced autophagy and apoptosis after silencing DDIT4 expression with synthetic siRNA with or without pretreatment of a mTOR inhibitor rapamycin in cardiomyocytes using Western blot analysis, fluorescence microscopy and TUNEL staining. Our results showed that METH exposure increased DDIT4 expression and decreased phosphorylation of mTOR that was accompanied with increased autophagy and apoptosis both in vitro and in vivo. These effects were normalized after silencing DDIT4. On the other hand, rapamycin promoted METH-induced autophagy and apoptosis in DDIT4 knockdown cardiomyocytes. These results suggest that DDIT4 mediates METH-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes.

Research on Multiple-Factor Dynamic Constitutive Model of Poured Asphalt Concrete.

This study conducted dynamic triaxial tests on a typical poured asphalt concrete material of core walls in Xinjiang, exploring the dynamic characteristics of poured asphalt concrete under various confining pressures, principal stress ratios, and vibration frequencies. On this basis, the dynamic constitutive relationship of poured asphalt concrete was investigated using the Hardin-Drnevich model. The results indicate that under different confining pressures, principal stress ratios, and vibration frequencies, the variation patterns of the backbone lines of dynamic stress-strain of poured asphalt concrete are basically identical, consistent with a hyperbolic curve. The confining pressure and principal stress ratio significantly affect the backbone line of dynamic stress-strain. By comparison, frequency has a minimal effect. The changing trends of dynamic elasticity modulus and damping ratio of poured asphalt concrete under various factors are almost the same. When the material has high dynamic stress and strain, the hysteresis loop is large. When the curve of the damping ratio becomes flat, the asymptotic constant can be used as the maximum damping ratio. The relationship between the reciprocal of the dynamic elasticity modulus and the dynamic strain of poured asphalt concrete exhibits a linear distribution. Under different ratios of confining pressure to principal stress, there are large discrepancies between the calculated values from the formula and the experimental fitting values of the maximum dynamic elasticity modulus, and the maximum relative errors reach 16.65% and 18.15%, respectively. Therefore, the expression for the maximum dynamic elasticity modulus was modified, and the calculated values using the modified formula were compared with the experimental fitting values. The relative errors are significantly reduced, and the maximum relative errors are 3.02% and 2.04%, respectively, in good agreement with the fitting values of the experimental data. The findings of this article render a theoretical basis and reference for the promotion and application of poured asphalt concrete.

Dual "on-off" signal conversion strategy based on surface plasmon coupling and resonance energy transfer for visual electrochemiluminescence ratiometric analysis of MiRNA-141.

An electrochemiluminescence (ECL) biosensor with a pair of new ECL emitters and a novel sensing mechanism was designed for the high-sensitivity detection of microRNA-141 (miRNA-141). Sulfur-doped boron nitrogen quantum dots (S-BN QDs) were initially employed to modify the cathode of the bipolar electrode (BPE), while the anode reservoir was [Ir(dfppy)2(bpy)]PF6/TPrA system. The next step involved attaching H1-bound ultra-small WO3-x nanodots (WO3-x NDs) to the S-BN QDs-modified BPE cathode via DNA hybridization. A strong surface plasmon coupling (SPC) effect was observed between S-BN QDs and WO3-x NDs, which allowed for the enhancement of the red and visible ECL emission from S-BN QDs. After target-induced cyclic amplification to produce abundant Zn2+ and Au NPs-DNA3-Au NPs (Au NPs-S3-Au NPs), Zn2+ could cleave DNA at a nucleotide sequence-specific recognition site to release the WO3-x NDs, resulting in the first diminution of cathode ECL signal and the first enhancement of anode ECL signal. Moreover, the ECL signal at cathode decreased for the second time and the emission of [Ir(dfppy)2(bpy)]PF6 was continuously enhanced after the introduction of Au nanoparticles-S3-Au nanoparticles on the cathode surface. Our sensing mode with a dual "on-off" signal conversion strategy shows a good detection capability for miRNAs ranging from 10-17 to 10-10 M, with a limit of detection (LOD) as low as 10-17 M, which has great application potential in biomedical research and clinical diagnosis.

Efficient pH-universal aqueous supercapacitors enabled by an azure C-decorated N-doped graphene aerogel.

Current aqueous supercapacitors (SCs) possess the relative low energy density, and there is therefore widespread interest in cost-effective fabrication of capacitive materials with promoted specific capacitance and/or broadened voltage window. Here, a redox-active azure C-decorated N-doped graphene aerogel (AC - NGA) is fabricated using a simple hydrothermal self-assembly method through strong noncovalent π-π interaction. AC - NGA highlights an excellent charge storage performance (a high 591F g-1 gravimetric capacitance under a current density of 1.0 A g-1 and ultrahigh voltage window of 2.3 V) under pH-universal conditions. The capacitive contribution of charge storage is 91.7%, exceeding or comparable to those of the best pseudocapacitors known. Furthermore, a symmetric AC - NGA//AC - NGA device realizes high energy and power densities (15.2-60.2 Wh kg-1 at 650-23,000 W kg-1) and excellent cycling stability in acidic, neutral, and basic aqueous solutions. This work offers a cost-effective strategy to combine redox dye molecules with heteroatom-doped graphene aerogel for building green efficient pH-universal aqueous supercapacitors.

Ternary dual S-scheme In2O3/SnIn4S8/CdS heterojunctions for boosted light-to-hydrogen conversion.

Developing artificial S-scheme systems with highly active catalysts is significant to long-term solar-to-hydrogen conversion. Herein, CdS nanodots-modified hierarchical In2O3/SnIn4S8 hollow nanotubes were synthesized by an oil bath method for water splitting. Benefiting from the synergy among the hollow structure, tiny size effect, matched energy level positions, and abundant coupling heterointerfaces, the optimized nanohybrid attains an impressive photocatalytic hydrogen evolution rate of 110.4 µmol/h, and the corresponding apparent quantum yield reaches 9.7% at 420 nm. On In2O3/SnIn4S8/CdS interfaces, the migration of photoinduced electrons from both CdS and In2O3 to SnIn4S8via intense electronic interactions contributes to the ternary dual S-scheme modes, which are beneficial to promote faster spatial charge separation, deliver better visible light-harvesting ability, and provide more reaction active sites with high potentials. This work reveals protocols for rational design of on-demand S-scheme heterojunctions for sustainably converting solar energy into hydrogen in the absence of precious metals.

Spatial charge separated two-dimensional/two-dimensional Cu-In2S3/CdS heterojunction for boosting photocatalytic hydrogen production.

Two-dimensional (2D) beta indium sulfide (ß-In2S3) shows great potential in photocatalytic hydrogen production due to its broad-spectrum response, relatively negative conduction band edge, high carrier mobility and low toxicity. However, the high charge recombination rate limits the application of In2S3. Here, we in-situ grew 2D cadmium sulfide (CdS) on the surface of In2S3 doped with copper ions (Cu2+) to construct a heterojunction photocatalyst that suppresses charge recombination. The in-situ grown method and shared sulfur composition were conducive to forming the efficient interface contact between In2S3 and CdS, promoting charge transfer and showing the high spatial charge separation rate, resulting in a hydrogen production rate of 868 µmol g-1h-1. The induced Cu2+ extended the light absorption range and stabilized the photocatalyst. By creating stable 2D/2D heterojunction photocatalysts with high charge separation efficiency, this work opens new possibilities for applying In2S3 materials in photocatalytic hydrogen production.

Poly(azure C)-coated CoFe Prussian blue analogue nanocubes for high-energy asymmetric supercapacitors.

Prussian blue analogues are considered as promising supercapacitor electrode materials due to their high theoretical capacitance and low cost. Yet, they suffer from poor electronic conductivity and cycling life. Here, a redox dye polymer, poly(azure C) (PAC), is in-situ grown uniformly on CoFe Prussian blue analogue (CoFePBA). As a polymer mediator, the PAC coating on each PBA not only enhances the electronic conductivity and surface area, but also improves the structural stability and specific capacitance of PBA. As a result, the optimized CoFePBA@PAC possesses ultrahigh specific capacitance (968.67 F g-1 at 1 A g-1), superior rate performance (665.78 F g-1 at 10 A g-1), and excellent long-cycling stability (92.45% capacity retention after 2000 cycles). As an application, a fabricated CoFePBA@PAC//AC asymmetric supercapacitor (AC = activated carbon) maintains 84.7% capacitance retention in 2000 cycles at 1 A g-1 and displays a superior specific energy of 29.16 W h kg-1 at the power density of 799.78 W kg-1. These results demonstrate that redox dye polymer-coated PBAs with outstanding performance have a promising prospect in the field of energy storage.

Thymic hypoplasia induced by copy number variations contributed to explaining sudden infant death based on forensic autopsies.

Thymic hypoplasia is a primary cellular immunodeficiency that causes susceptibility to serious infections leading to sudden death in infants. Some genetic disorders in humans could result in the evident permanent hypoplasia or occasional aplasia of the thymus at birth. However, determining the genetic etiology of thymic hypoplasia is challenging for the sudden infant death due to primary cellular immunodeficiency. In this study, in order to find the fundamental reasons for sudden death of infants with thymic hypoplasia, 5 infants with suspected thymic hypoplasia and 10 control infants were assessed, and the immunohistochemistry and DNA analysis were used to investigate whether the infants with thymic hypoplasia had DiGeorge syndrome (DGS) with copy number variations (CNVs) in 22q11.2 and other chromosomes. The results showed that the weight of the thymus was significantly lower than the normal except the case 4, and that all the infants had hypocalcemia and a significant decrease or even absence of the markers CD1a, CD2, CD3, CD4 and CD8, which are related to T-cell maturation. In addition, multiplex ligation-dependent probe amplification (MLPA) analysis showed that these infants carried CNVs in 22q11.2 and other associated chromosomes with deletion and duplication of 25 genes. The results of thymus weight, histopathology, molecular pathology and MLPA analysis suggested that DGS predominantly with thymic hypoplasia induced by CNVs caused the sudden death of these infants under various infections or other unexplained reasons, which may provide new insights into the diagnosis of sudden infant death and could help the parents of deceased infants to attach more importance of genetic screening and thymus ultrasound to reduce the postnatal mortality of the infant, and demonstrates the value of genetic diagnosis in the forensic pathology.

S-scheme photocatalysis induced by ZnIn2S4 nanoribbons-anchored hierarchical CeO2 hollow spheres for boosted hydrogen evolution.

Developing S-scheme systems with impressive photocatalytic performance is of huge meaning in realizing the long-term conversion of solar energy into hydrogen. Herein, ZnIn2S4 nanoribbons were integrated with hierarchical CeO2 hollow spheres to construct heterostructure using an oil bath approach under mild conditions. The optimized CeO2/ZnIn2S4 presented a superior photocatalytic hydrogen production rate of 69 µmol/h, which is about 4.9 and 11.5 times greater than pristine ZnIn2S4 and CeO2, respectively. In addition, its apparent quantum yield achieved 7.6% at 420 nm. The improved photoactivity of the CeO2/ZnIn2S4 heterojunction can be referable to the cooperative effects of the aligned bandgap structures, strong visible-light-harvesting capacity, and interfacial interactions via the internal electric field. This study provides insights into the protocols for rational design of S-scheme heterojunction catalysts for high-efficiency hydrogen evolution via sustainable photocatalytic water splitting.

Highly dispersive Ru confined in porous ultrathin g-C3N4 nanosheets as an efficient peroxymonosulfate activator for removal of organic pollutants.

Ru species were loaded on a two-dimensional (2D) material of graphitic carbon nitride (2D g-C3N4) to serve as the efficient AOP catalysts. The catalytic activity was closely related to the dispersion degree of Ru, as determined by the inherent nanoarchitecture of the supporting material. Ultrathin g-C3N4 nanosheets with a unique porous structure were fabricated by further thermally oxidizing and etching bulk g-C3N4 (bCN) in air. Homogeneous dispersion of Ru species was successfully achieved on the porous few-layered g-C3N4 nanosheets (pCN) by stirring, washing, freeze drying and annealing processes to obtain Ru-pCN catalysts, whereas bCN or multilayered g-C3N4 (mCN) led to the aggregation of Ru nanoparticles in Ru-bCN and Ru-mCN materials. The conventional impregnation method also caused the resulting Ru-pCN-imp catalyst with undesirable Ru aggregation in spite of employing pCN. The optimal 4.4Ru-pCN removed 100% of 2,4,6-trichlorophenol (TCP) within only 3 min, superior to its counterpart samples, and exhibited remarkable degradation efficiencies for methyl orange, neutral red, 4-chlorophenol, tetracycline and oxytetracycline. Mechanistic studies suggested that four radicals, e.g., •OH, SO4• -, O2• - and 1O2 were generated during the peroxymonosulfate (PMS) activation, in which SO4• - and 1O2 played a major role.

Edge-Rich Bicrystalline 1T/2H-MoS2 Cocatalyst-Decorated {110} Terminated CeO2 Nanorods for Photocatalytic Hydrogen Evolution.

Developing all-solid-state Z-scheme systems with highly active photocatalysts are of huge interest in realizing long-term solar-to-fuel conversion. Here we reported an innovative hybrid of {110}-oriented CeO2 nanorods with edge-enriched bicrystalline 1T/2H-MoS2 coupling as efficient photocatalysts for water splitting. In the composites, the metallic 1T phase acts as an excellent solid state electron mediator in the Z-scheme, while the 2H phase and CeO2 are the adsorption sites of the photosensitizer and reactant (H2O), respectively. Through optimal structure and phase engineering, 1T/2H-MoS2@CeO2 heterojunctions simultaneously achieve high charge separation efficiency, proliferated density of exposed active sites, and excellent affinity to reactant molecules, reaching a superior hydrogen evolution rate of 73.1 µmol/h with an apparent quantum yield of 8.2% at 420 nm. Furthermore, density functional theory calculations show that 1T/2H-MoS2@CeO2 possesses the advantages of intensive electronic interaction from the built-in electric field (negative MoS2 and positive charged CeO2) and reduced H2O adsorption/dissociation energies. This work sheds light on the design of on-demand noble-metal-free Z-scheme heterostructures for solar energy conversion.

Bipolar electrode ratiometric electrochemiluminescence biosensing analysis based on boron nitride quantum dots and biological release system.

In this article, we developed a novel ECL ratiometry on a closed bipolar electrode (BPE) for the sensitively and accurately detection of miRNA-21. High quantum yield and low toxicity BNQDs was synthesized and coated at BPE cathode as an ECL emitter, while the anode of BPE was calibrated via another ECL material, Ir(df-ppy)2(pic) (Firpic). The electron neutrality at both ends of the BPE electrically coupled the reactions on each pole of the BPE. Therefore, one electrochemical sensing reaction could be quantified at one end of the BPE. By the hybridization of target miRNA-21 and hairpin, the glucose blocked in MSNs by the hairpin was released and reacted with glucose oxidase (GOD) to generate H2O2, thereby reducing the ECL signal of the cathode BNQDs/K2S2O8 system and promoting ECL signal of anode Firpic/TPrA. Further, the G-quadruplex formed by unreacted hairpin bases consumed H2O2, which not only recovered the ECL of BNQDs, but also further improved the ECL emission of Firpic. Therefore, the concentration of miRNA-21 could be measured by the ECL ratio of BNQDs and Firpic. The data showed that the detection limit was 10-15 M (S/N = 3) with the linear range of 10-15 M to 10-9 M. The strategy of the BPE-ECL ratio method based on BNQDs showed a good prospect in clinical application.