Hierarchical Ti3C2/BiVO4 microcapsules for enhanced solar-driven water evaporation and photocatalytic H2 evolution.

Desalination processes frequently require a lot of energy to generate freshwater and energy, which depletes resources. Their reliance on each other creates tension between these two vital resources. Herein, hierarchical MXene nanosheets and bismuth vanadate (Ti3C2/BiVO4)-derived microcapsules were synthesized for a photothermal-induced photoredox reaction for twofold applications, namely, solar-driven water evaporation and hydrogen (H2) production. For this purpose, flexible aerogels were fabricated by introducing Ti3C2/BiVO4 microcapsules in the polymeric network of natural rubber latex (NRL-Ti3C2/BiVO4), and a high evaporation rate of 2.01 kg m-2 h-1 was achieved under 1-kW m-2 solar intensity. The excellent performance is attributed to the presence of Ti3C2/BiVO4 microcapsules in the polymeric network, which provides balanced hydrophilicity and broadband sun absorption (96 %) and is aimed at plasmonic heating with microscale thermal confinement tailored by heat transfer simulations. Notably, localized plasmonic heating at the catalyst active sites of the Ti3C2/BiVO4 heterostructure promotes enhanced photocatalytic H2 production evolved after 4 h of reaction is 9.39 µmol, which is highly efficient than pure BiVO4 and Ti3C2. This method turns the issue of water-fuel crisis into a collaborative connection, presenting avenues to collectively address the anticipated demand rather than fostering competition.

[Production and antigenicity analysis of a recombinant insulinoma associated protein-2 in HEK293 cells].

Insulinoma-associated protein-2 (IA-2) is a transmembrane glycoprotein belonging to the tyrosine phosphatase-like protein family as well as an important autoantigen in the diagnosis of type 1 diabetes. IA-2 products have been marketed in Europe and the United States. At present, commercially available IA-2 antigens are either the recombinant IA-2ic domain or the IA-2 naturally extracted from bovine islets. However, the recombinant IA-2 antigen displays weak positive in clinic practice, which often results in occasional detection failures, thus cannot completely replace the naturally extracted IA-2 antigen. In this study, an HEK293 expression system was used to explore the production of recombinant IA-2. An IA-2 transmembrane fragment (IA-2 TMF) located at amino acid position 449-979, also known as the natural membrane protein form of IA-2, was produced in HEK293 through transfection, and both the expression conditions and dissolution conditions of the membrane protein were also optimized. The purified membrane protein yield was 0.78 mg/L cell culture. Subsequently, the antigen activity of IA-2 TMF was compared with RSR rhIA-2 through enzyme linked immunosorbent assay. The serum of 77 type 1 diabetes patients and 32 healthy volunteers were detected. Receiver operating characteristic curve (ROC) curve was used to characterize the sensitivity and specificity of the test results. The results showed that the sensitivity of IA-2 TMF was 71.4% (55/77), while the sensitivity of RSR rhIA-2 was 63.6% (49/77), and the specificity of both antigens were all 100%. There was no significant difference in specificity between the two antigens, but the sensitivity of IA-2 TMF was appreciably better than that of the imported gold standard RSR rhIA-2 antigen. In conclusion, the recombinant IA-2 TMF produced in HEK293 cells can be used as a raw material to develop in vitro diagnostic reagents for type 1 diabetes.

Sheet-on-sheet ZnIn2S4@RGO-modified separators with abundant sulfur vacancies for high-performance Li-S batteries.

A novel sheet-on-sheet architecture with abundant sulfur vacancies (Vs) is designed by in situ growth of flake-like ZnIn2S4 on the reduced graphene oxide (Vs-ZIS@RGO) surface, which serves as a functional layer on the separators for high-performance lithium-sulfur batteries (LSBs). Benefiting from the sheet-on-sheet architecture, the separators exhibit rapid ionic/electronic transfer, which is capable of supporting fast redox reactions. The vertically ordered ZnIn2S4 shortens the diffusion pathways of lithium-ions and the irregularly curved nanosheets expose more active sites to effectively anchor lithium polysulfides (LiPSs). More importantly, the introduction of Vs adjusts the surface or interface electronic structure of ZnIn2S4, enhancing the chemical affinity to LiPSs while accelerating conversion reaction kinetics of LiPSs. As expected, the batteries with Vs-ZIS@RGO modified separators exhibit an initial discharge capacity of 1067 mA h g-1 at 0.5C. Even at 1C, the excellent long cycle stability (710 mA h g-1 over 500 cycles) with an ultra-low decay rate of 0.055% per cycle is also attained. This work proposes a strategy of designing the sheet-on-sheet structure with rich sulfur vacancies, which provides a new perspective to rationally devise durable and efficient LSBs.

φC31 -Mediated cassette exchange in Sf9 insect cells for stable expression.

Insect cells, especially Sf9 cells, are commonly used in biomanufacturing due to their advantages in high expression levels and post-translational modification. However, the development of stable expression cell lines via random integration tended to be unstable. Site-specific integration (SSI) is an alternative strategy. In this study, a φC31 -mediated cassette exchange system in Sf9 cells was established for SSI. The tagging cassette with the reporter gene egfp was randomly inserted into the cell genome. Potential platform cell lines were obtained by fluorescence-activated cell sorting (FACS) and single-cell cloning. Platform cell lines were selected by assessing the fluorescence expression, stability, and growth kinetics of cell lines. The selected platform cell lines were co-transfected with the φC31-containing plasmid and the targeting cassette. Green-fluorescence-negative clones were screened by hygromycin resistance and FACS. The resulting cell clones exhibited the expression properties of the platform cell lines. The rapid development of cell lines for the production of influenza subunit vaccines by the cassette exchange system demonstrated that the system constituted a versatile and reusable platform for the production of various recombinant proteins. Overall, the φC31-mediated cassette exchange system in Sf9 cells has the potential to facilitate and accelerate biologics development.

[Expression of zinc transporter 8 in Saccharomyces cerevisiae and its antigenicity analysis].

Zinc transporter 8 (ZnT8) is an important candidate antigen for type Ⅰ diabetes. The autoantibody detection kit based on ZnT8 can be used to help diagnose type Ⅰ diabetes, and the related products have been launched in Europe and the United States. Since the recombinant production system of active ZnT8 has not been established in China, this key raw material is heavily dependent on imports. We used Saccharomyces cerevisiae to carry out the recombinant expression of ZnT8. First, multiple antigenic forms of ZnT8 were designed as C-terminal haploid (C), C-terminal diploid (C-C), and N-terminal and C-terminal concatemers (N-C). The proteins were expressed, purified and tested for antigenicity by bridging-type ELISA. The serum of 13 patients with type Ⅰ diabetes and the serum of 16 healthy volunteers were detected. C, N-C, and C-C proteins had similar detection rates, which were 53.8% (7/13), 61.5% (8/13) and 53.8% (7/13). The specificity of the three groups was 100% (16/16). The detection value on positive samples P3, P4, and P8 increased by more than 90%, indicating better serum antibody recognition ability. Finally, N-C protein was selected for further serum sample testing, and the test results were characterized by receiver operating characteristic (ROC) curve for sensitivity and specificity. Compared with imported gold standard antigen, the sensitivity was 76.9% (10/13) and the specificity was 87.5% (14/16). There was no significant difference in the sensitivity of the method, but the specificity needed to be improved. In conclusion, the ZnT8 N-terminal and C-terminal concatemer protein developed based on S. cerevisiae expression system is expected to be a key alternative raw material in the development of in vitro diagnostic reagents for type Ⅰ diabetes.

Aptamer-Based Solution-Gated Graphene Transistors for Highly Sensitive and Real-Time Detection of Thrombin Molecules.

Thrombin is an important biomarker for various diseases and biochemical reactions. Rapid and real-time detection of thrombin that quickly neutralizes in early coagulation in the body has gained significant attention for its practical applications. Solution-gated graphene transistors (SGGTs) have been widely studied due to their higher sensitivity and low-cost fabrication for chemical and biological sensing applications. In this paper, the ssDNA aptamer with 29 bases was immobilized on the surface of the gate electrode to specifically recognize thrombin. The SGGT sensor achieved high sensitivity with a limit of detection (LOD) up to fM. The LOD was attributed to the amplification function of SGGTs and the suitable aptamer choice. The ssDNA configuration folding induced by thrombin molecules and the electropositivity of thrombin molecules could arouse the same electrical response of SGGTs, helping the device obtain a high sensitivity. The channel current variation of sensors had a good linear relationship with the logarithm of thrombin concentration in the range of 1 fM to 10 nM. The fabricated device also demonstrated a short response time to thrombin molecules, and the response time to the 1 fM thrombin molecules was about 150 s. In summary, the sensing strategy of aptamer-based SGGTs with high sensitivity and high selectivity has a good prospect in medical diagnosis.

Harvesting Solar Energy by Flowerlike Carbon Cloth Nanocomposites for Simultaneous Generation of Clean Water and Electricity.

Harvesting solar energy for photothermal conversion in an efficient manner for steam-electricity cogeneration is particularly opportune in the context of comprehensive solar utilization to address the challenge of a global shortage of fresh water. However, the fragile solar thermal devices and the single-energy utilization pattern greatly hinder extensive solar energy exploitation and practical application. Herein, a flexible carbon cloth nanocomposite with a biomimetic pelargonium hortorum-petal-like surface that embraces all desirable chemical and physical properties, that is, enhanced light acquisition, excellent photothermal property, and operational durability, for high-performance solar-driven interfacial water evaporation distillation is reported. Combined with the two-dimensional water channel, the solar evaporator shows a solar-to-steam conversion efficiency of 93% under the simulated solar illumination of 1 kW m-2. More strikingly, the solar steam generation-induced electricity based on the practical consideration toward more infusive solar thermal application is proposed. Such integrative steam-electricity generators presented here provide an attractive method to produce on-site electricity and fresh water in an individualized mode in various resource-constrained areas.

Biomass-Derived Bilayer Solar Evaporator with Enhanced Energy Utilization for High-Efficiency Water Generation.

Solar-driven evaporation has been recognized as a promising approach to address global crises of drinking water via virtue of abundant and green solar energy. However, a great challenge still exists for achieving efficient usage of solar energy combined with fast water evaporation. Here, a double-structural solar evaporator consists of an upper copper sulfide (CuS) agar-based aerogel and a bottom molybdenum carbide/carbon (MoCC) composite of cotton fibers-derived aerogel (CuSAA/MoCCFA), which is constructed for solar evaporation. The CuS layer performs as a solar-thermal converter with efficient light adsorption and prominent thermally localized ability, while the bottom layer (superhydrophilic porous aerogel) guarantees sufficient water transportation and excellent thermal insulation. The fully integrative solar evaporator has an attractive water evaporation rate of 2.44 kg m-2 h-1 with a superb solar-thermal conversion efficiency of 92.77% under 1 sun illumination. More notably, the bilayer aerogel exhibits long-term durability in high-salinity media during solar-driven desalination. In addition, a solar absorber assisted with low-temperature phase change materials comprise the solar evaporation system, which is aimed at solar-thermal energy storage and reutilization for conquering solar intermittence. Such superior performance of a comprehensive solar desalination system provides a new avenue for highly efficient and suitable clean water production under natural sunlight conditions.

Chinese hydrangea lantern-like Co9S8@MoS2 composites with enhanced lithium-ion battery properties.

Chinese hydrangea lantern-like Co9S8@MoS2 composites are prepared by a facile solvothermal method. Ultra-thin MoS2 nanosheets as the shells grow tightly and uniformly on the surface of the Co9S8 core. Due to their unique hierarchical core-shell structure and novel morphology, the composites show excellent electrochemical performance as the anode materials of lithium-ion batteries. They can deliver reversible discharge capacities of around 1298, 1150, 1089, 1018 and 941 mA h g-1 at the current densities of 0.1, 0.5, 1, 1.5 and 2.0 A g-1, respectively. Moreover, the Co9S8@MoS2 composites can still maintain a discharge capacity of 1048 mA h g-1 after 300 cycles at a current density of 1.0 A g-1.

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.

Bifunctional, Moth-Eye-Like Nanostructured Black Titania Nanocomposites for Solar-Driven Clean Water Generation.

Solar steam generation and photocatalytic degradation have been regarded as the most promising techniques to address clean water scarcity issues. Although enormous efforts have been devoted to exploring high-efficiency clean water generation, many challenges still remain in terms of single decontamination function, relatively low efficiency, and inability to practical application. Herein, we first report the bioinspired fabrication of black titania (BT) nanocomposites with moth-eye-like nanostructures on carbon cloth for solar-driven clean water generation through solar steam generation and photocatalytic degradation. The moth-eye-like BT nanoarrays can largely prolong the effective propagation path of absorbing light and enhance the scattering of light, thereby exhibiting outstanding light absorption of 96% in the full spectrum. Such hierarchical-nanostructured BT nanocomposites not only impressively achieve solar steam efficiency of 94% under a simulated light of 1 kW m-2 but also show the prominent performance of desalination and steam generation in real life condition. In addition, 96% of rhodamine B is degraded using BT nanocomposites as a photocatalyst in 100 min. The moth-eye-like bioinspired designing concept and bifunctional applications in this study may open up a new strategy for maximizing solar energy utilization and clean water generation.

PEGylated Self-Growth MoS2 on a Cotton Cloth Substrate for High-Efficiency Solar Energy Utilization.

Solar steam generation, utilizing abundant solar energy and floating photothermal materials, has been considered as one of the most sustainable, efficient ways to solve the problem of water shortage. Here, a new system for solar steam generation is fabricated based on a PEGylated MoS2-cotton cloth (PMoS2-CC). 80.5-90 ± 3.5% of high-efficiency solar steam generation is achieved under a light density of 1-5 kW m-2 because of the good gas permeability of CC and the hydrophilic property of PMoS2-CC. The self-growth PMoS2-CC provides good photothermal performances in pure water and saline water. The water evaporation rate with PMoS2-CC keeps a stable value after a long-time illumination (4 h) and 32 times cycle tests. Our result provides a way to prepare pure water in the applications for alleviating a scarcity of drinking water.

Data on novel C fibers@MoSe2 nanoplates core-shell composite for highly efficient solar-driven photocatalytically degrading environmental pollutants.

The data presented in this article are related to a research article entitled 'Highly efficient solar-driven photocatalytic degradation on environmental pollutants over a novel C fibers@MoSe2 nanoplates core-shell composite' (Wang et al., 2018) [1]. In this article, we report original data on the synthesis processes optimization of the proposed composite together with its formation mechanism. The report includes the composition, microstructure and morphology of the corresponding samples, and the photocatalytic activity and stability of the optimal composite. Compared with commercially available MoSe2 powder, the reaction rate constant of the optimal composite catalyst for the degradation of methylene blue (MB) and rhodamine B (RhB) under simulated sunlight irradiation (SSI) could be increased in a factor of about 14 and 8, respectively. The data are presented in this format to allow the comparison with those from other researchers in this field, and understanding the synthesis and photocatalysis mechanism of similar catalysts.

Highly efficient solar-driven photocatalytic degradation on environmental pollutants over a novel C fibers@MoSe2 nanoplates core-shell composite.

As an important member of two-dimensional transition metal dichalcogenides, MoSe2 has a wide range of photoelectrochemical properties. However, MoSe2 alone can not directly be used as photocatalyst for its poor performance owing to the strong recombination of photogenerated electron-hole pairs. Here, we propose a novel C fibers@MoSe2 nanoplates core-shell composite, which was prepared by a facile, one-step thermal evaporation method. The composite has a remarkable feature of numerous MoSe2 thin nanoplates grown in-situ, densely and even vertically on the surface of the C fibers. Due to the effective separation of photogenerated electron-hole pairs promoted by the prompt transfer of photogenerated electrons through C fibers, compared with commercially available pure MoSe2 powder, such composite exhibits greatly improved solar-driven photocatalytic activity and high stability for the degradation of various organic/inorganic environmental pollutants including methylene blue, rhodamine B, p-chlorophenol and K2Cr2O7 aqueous solutions, showing the great potential for environmental remediation by degrading toxic industrial chemicals in waste water using sunlight. Moreover, this one-step thermal evaporation is an easy-handling, eco-friendly and low-cost synthesis method, which is suitable for large-scale production.

C Fibers@WSe2 Nanoplates Core-Shell Composite: Highly Efficient Solar-Driven Photocatalyst.

Recently, WSe2 as a typical transition metal dichalcogenide compound has attracted extensive attention due to its potential applications in electronic and optoelectronic devices. However, WSe2 alone cannot be directly used as a photocatalyst due to its inferior performance possibly caused by the strong recombination of photogenerated electron-hole pairs. Here a novel C fibers@WSe2 nanoplates core-shell composite (NPCSC) was successfully synthesized via facile, one-step thermal evaporation, in which numerous WSe2 thin nanoplates were in situ, densely and even vertically grown on the surface of the C fibers. Such composite presents highly solar-driven photocatalytic activity and stability for the degradation of various organic aqueous dyes including methylene blue and rhodamine B, and highly harmful gases like toluene, showing the great potential for environmental remediation by degrading toxic industrial chemicals using sunlight. Under simulated sunlight irradiation, comparing with commercially available WSe2 powder, the as-synthesized C fibers@WSe2 NPCSC presents significantly enhanced reaction rate constants by a factor of approximately 15, 9, and 3 for the degradation of aqueous methylene blue, aqueous rhodamine B, and gaseous toluene, respectively, due to the effective separation of photogenerated electron-hole pairs promoted by the rapid transfer of photogenerated electrons through C fibers. Moreover, this one-step thermal evaporation is an easy-handling, environmentally friendly, and low-cost synthesis method, which is suitable for large-scale production.

Bulk Fabrication of WS2 Nanoplates: Investigation on the Morphology Evolution and Electrochemical Performance.

Two-dimensional layered chalcogenide WS2, similar to graphene, is considered to be very interesting for materials scientists. However, to make it a useful material platform, it is necessary to develop sophisticated synthesis methods to control its morphology. In this paper, we present a simple approach to prepare various morphologies of WS2 nanostructures by direct thermal evaporation of WO3 and S powders onto Si substrates sputtered with W film without using any nanostructured W-contained precursors and highly toxic sulfide gases. This method can produce bulk quantities of pure hexagonal, horizontally grown WS2 nanoplates, vertically grown nanoplates, and nanoplate-formed flowers simply by tuning the distance between the substrate and source powders. The synthesis mechanism and morphology evolution model were proposed. Moreover, when employed as a thin-film anode material, the Li-ion battery with as-prepared, vertically grown WS2 nanoplates presented a rechargeable performance between 3 and 0.01 V with a discharge capacity of about 773 mAh/cm(3) after recycling three times, much better than its already-reported counterparts with randomly distributed WS2 nanosheet electrodes, but the battery with horizontally grown WS2 nanoplates could not show any charge-discharge cycling property, which could be attributed to the different structures of WS2 anodes for Li(+) ion intercalation or deintercalation.

Positive impedance humidity sensors via single-component materials.

Resistivity-type humidity sensors have been investigated with great interest due to the increasing demands in industry, agriculture and daily life. To date, most of the available humidity sensors have been fabricated based on negative humidity impedance, in which the electrical resistance decreases as the humidity increases, and only several carbon composites have been reported to present positive humidity impedance. However, here we fabricate positive impedance humidity sensors only via single-component WO3-x crystals. The resistance of WO3-x crystal sensors in response to relative humidity could be tuned from a negative to positive one by increasing the compositional x. And it was revealed that the positive humidity impedance was driven by the defects of oxygen vacancy. This result will extend the application field of humidity sensors, because the positive humidity impedance sensors would be more energy-efficient, easier to be miniaturized and electrically safer than their negative counterparts for their lower operation voltages. And we believe that constructing vacancies in semiconducting materials is a universal way to fabricate positive impedance humidity sensors.

Nonlinear saturable absorption of vertically stood WS2 nanoplates.

We report the nonlinear optical (NLO) properties of vertically stood WS2 nanoplates excited by 532-nm picosecond laser light. The nanoplates were synthesized by a no-catalyst thermal evaporation process. Raman spectroscopy and x-ray diffraction pattern indicate that the nanoplates are of high crystal quality. The nanoplates exhibit large nonlinear saturable absorption but negligible nonlinear refraction. Mechanisms of the NLO response are proposed.