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In green plants, solar‐powered electrons are transferred through sophistically arranged photosystems and are subsequently channelled into the Calvin cycle to generate chemical energy. Inspired by the natural photosynthetic scheme, a photoelectrochemical cell (PEC) is constructed configured with protonated graphitic carbon nitride (p‐g‐C3N4) and carbon nanotube hybrid (CNT/p‐g‐C3N4) film cathode, and FeOOH‐deposited bismuth vanadate (FeOOH/BiVO4) photoanode for the production of industrially useful chiral alkanes using an old yellow enzyme homologue from Thermus scotoductus (TsOYE). In the biocatalytic PEC platform, photoexcited electrons provided by the FeOOH/BiVO4 photoanode are transferred to the robust and self‐standing CNT/p‐g‐C3N4 hybrid film that electrocatalytically reduces flavin mononucleotide (FMN) mediator. The p‐g‐C3N4 promotes a two‐electron reduction of FMN coupled with an accelerated electron transfer by the conductive CNT network. The reduced FMN subsequently delivers the electrons to TsOYE for the highly enantioselective conversion of ketoisophorone to (R)‐levodione. Under light illumination (>420 nm) and external bias, (R)‐levodione is synthesized with the enantiomeric excess value of above 83%, not influenced by the scale of applied bias, simultaneously exhibiting stable and high current efficiency. The results suggest that the biocatalytic PEC made up of economical materials can selectively synthesize high‐value organic chemicals using water as an electron donor.  相似文献   

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Organelles, i.e., internal subcompartments of cells, are fundamental to spatially separate cellular processes, while controlled intercompartment communication is essential for signal transduction. Furthermore, dynamic remodeling of the cytoskeleton provides the mechanical basis for cell shape transformations and mobility. In a quest to develop cell‐like smart synthetic materials, exhibiting functional flexibility, a self‐assembled vesicular multicompartment system, comprised of a polymeric membrane (giant unilamellar vesicle, GUV) enveloping polymeric artificial organelles (vesicles, nanoparticles), is herein presented. Such multicompartment assemblies respond to an external stimulus that is transduced through a precise sequence. Stimuli‐triggered communication between two types of internal artificial organelles induces and localizes an enzymatic reaction and allows ion‐channel mediated release from storage vacuoles. Moreover, cytoskeleton formation in the GUVs' lumen can be triggered by addition of ionophores and ions. An additional level of control is achieved by signal‐triggered ionophore translocation from organelles to the outer membrane, triggering cytoskeleton formation. This system is further used to study the diffusion of various cytoskeletal drugs across the synthetic outer membrane, demonstrating potential applicability, e.g., anticancer drug screening. Such multicompartment assemblies represent a robust system harboring many different functionalities and are a considerable leap in the application of cell logics to reactive and smart synthetic materials.  相似文献   

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In this paper, we describe a novelapproach to mobile station positioning using a GSMmobile phone. The approach is based on the use of aninherent feature of the GSM cellular system (themobile phone continuously measures radio signalstrengths from a number of the nearest base stations(antennas)) and on the use of this information to estimatethe phone's location. The current values of the signalstrengths are processed by a trained artificial neuralnetwork executed at the computer attached to themobile phone to estimate the position of the mobilestation in real time. The neural network configurationis obtained by using a genetic algorithm that searchesthe space of specific neural network types anddetermines which one provides the best locationestimation results. Two general methods are explored:the first is based on using a neural network forclassification and the second uses functionapproximation. The experimental results are reportedand discussed.  相似文献   

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Solar‐to‐hydrogen (STH) conversion through unassisted artificial photosynthesis (APS) devices is one of the promising and environmentally friendly strategies for sustainable development. However, the practical large‐scale application of the unassisted APS devices is impeded by the need for expensive noble metal‐based catalysts in photovoltaics and/or electrolyzers. Herein, well‐aligned 2D NixSy nanowalls (2D NixSy NWs) on a 3D nitrogen‐doped graphene foam (3D NGF) are synthesized and further employed it in unassisted APS. Due to the positive synergistic effect between the highly electrocatalytic activity of NixSy NW and excellent conductivity of NGF, this low cost material of (2D/3D) NixSy NW/NGF is highly efficient as a multifunctional catalyst in various applications: a counterelectrode for dye‐sensitized solar cell (DSSC) and a “bifunctional” electrocatalyst for oxygen and hydrogen evolution for electrocatalytic overall water splitting. Furthermore, three NixSy NW/NGF‐based DSSCs as a tandem cell for unassisted solar‐driven overall water splitting is connected, using NixSy NW/NGF itself on nickel foams as the anode and cathode. Impressively, such integrated photovoltaic‐electrolyzer APS device can achieve an STH efficiency of 3.2% with an excellent stability and low cost. This work opens an avenue to advanced multifunctional materials for the low‐cost and unassisted solar‐driven overall water splitting.  相似文献   

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A general protocol to synthesize superparamagnetic molecularly imprinted polymer particles, using a RAFT‐mediated approach, is described. S‐ propranolol‐imprinted composites were obtained by functionalizing commercially available amino‐modified Fe3O4 nanoparticles with a trithiocarbonate agent and subsequently by polymerizing thin molecularly imprinted layers. Different parameters were optimized and their effect on both nanomorphology and imprinting behaviour was studied. Optimum conditions allowed the synthesis of 40 nm composite particles with a 7 nm MIP shell, exhibiting superparamagnetic properties and specific molecular recognition of S‐ propranolol. The possibility of fine‐tuning the surface properties of the particles is demonstrated by using the “living” nature of active RAFT fragments present on the surface of the composites to further functionalize the particles with ethylene glycol methacrylate phosphate polymer brushes.  相似文献   

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Creating an intelligent artificial cell wall to endow fabricated cells with more advanced functionalities is highly desirable. Here, an efficient and cytocompatible approach to generate a type of viable artificial cell wall based on direct self‐assembly of coacervate microdroplets on individual cellular surface is developed, which can protect the fabricated cell against various external stresses and can then prolong the storage of the fabricated cells over two months. Moreover, as a type of viable artificial cell wall, it can not only help the fabricated cell sequester nutrients or functionalized substances such as catalase, or iron oxide nanoparticles actively from the solution which then makes the fabricated cell more versatile but also allows the fabricated cell proliferate. Significantly, the artificial cell wall also shows heritable behavior that can reserve its protection to as far as the third‐generation daughter cell. Undoubtedly, such an illustrated artificial cell wall provides a conceptually new and promising technique toward the cell‐based research as well as application of next generation.  相似文献   

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The catalytic nature of semiconducting quantum dots (QDs) for photocatalytic hydrogen (H2) evolution can be thoroughly aroused, not because of coupling with external cocatalysts, but through partially covering controlled amount of ZnS shell on the surface. Specifically, CdSe QDs, with an optimal coverage of ZnS (≈46%), can produce H2 gas with a constant rate of ≈306.3 ± 21.1 µmol mg?1 h?1 during 40 h, thereby giving a turnover number of ≈(4.4 ± 0.3) × 105, which is ≈110‐fold to that of unmodified CdSe QDs under identical conditions. The performance of H2 evolution is comparable to or even better than the commonly used external cocatalysts, e.g., metal complexes, noble metals assisted photosystems. Mechanistic insights indicate that the dramatically enhanced activity and stability of bare QDs for photocatalytic H2 production are derived from (i) inhibiting exciton annihilation at trap states, (ii) preventing the photo‐oxidation of core frameworks, and (iii) retaining tunneling efficiencies of photogenerated electrons and holes to reactive sites with partial ZnS coverage.  相似文献   

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This Feature Article discusses utility of multilayered polymer capsules in biomedicine, specifically in drug delivery and in design of artificial organelles and cells. We provide a critical view on recent successes and identified shortcomings of these capsules in delivery of therapeutic cargo and outline plausible further developments of capsules as candidate drug carriers. A special emphasis is placed on poly(methacrylic acid) hydrogel capsules as successful carriers used in delivery of anticancer drugs and protein and peptide vaccines. We further present a novel biomedical approach whereby the same vessel acts first as a microreactor and then as a carrier for de novo synthesized therapeutic cargo. Finally, utility of polymer capsules in design of cell mimics is discussed with an emphasis on assembly and performance of capsosomes, polymer capsules with liposomal subcompartments. This presentation of capsules in biomedicine aims to provide an overview of past achievements and existing challenges associated with these candidate vessels and to stimulate further research interest from a broad scientific audience.  相似文献   

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2-photon polymerization is a promising technology for creating complex, microscale 3D matrices for biomedical and also bioprinting applications. Cancer research provides compelling uses for this strategy, in particular, for generating a 3D constraint around multicellular spheroids. Because these spheroids are inhomogeneous in size and shape, the ability to target a spheroid composed of a few living cells requires geometrical control of the printing shape in situ. In this study, it is presented that two-photon lithography can be used to study complex phenomena involved in cancer progression, such as collective 3D cell migration in situ in vitro. This method allows the spatial and temporal control of cancer cell migration from single spheroids, using dome-shaped confinements with micrometer-sized openings. The confinement of the spheroids leads to a decreased migration speed and affects actin dynamics. Furthermore, this methodology provides a novel way of analyzing the behavior of specific regions of multicellular structures, by enabling the separation of multicellular structures, while keeping them alive. Ultimately, this study demonstrates a new way to use two-photon lithography for controlling the growth, migration and morphological cues of live cells, thus opening new avenues toward the dynamic in situ control of living 3D structures.  相似文献   

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Nonmetallic plasmonic heterostructure TiO2‐mesocrystals/WO3?x‐nanowires (TiO2‐MCs/WO3?x‐NWs) are constructed by coupling mesoporous crystal TiO2 and plasmonic WO3?x through a solvothermal procedure. The continuous photoelectron injection from TiO2 stabilizes the free carrier density and leads to strong surface plasmon resonance (SPR) of WO3?x, resulting in strong light absorption in the visible and near‐infrared region. Photocatalytic hydrogen generation of TiO2‐MCs/WO3?x‐NWs is attributed to plasmonic hot electrons excited on WO3?x‐NWs under visible light irradiation. However, utilization of injected photoelectrons on WO3?x‐NWs has low efficiency for hydrogen generation and a co‐catalyst (Pt) is necessary. TiO2‐MCs/WO3?x‐NWs are used as co‐catalyst free plasmonic photocatalysts for CO2 reduction, which exhibit much higher activity (16.3 µmol g?1 h?1) and selectivity (83%) than TiO2‐MCs (3.5 µmol g?1 h?1, 42%) and WO3?x‐NWs (8.0 µmol g?1 h?1, 64%) for methane generation under UV–vis light irradiation. A photoluminescence study demonstrates the photoelectron injection from TiO2 to WO3?x, and the nonmetallic SPR of WO3?x plays a great role in the highly selective methane generation during CO2 photoreduction.  相似文献   

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Excessive self-DNAs recognized by intracellular DNA sensors can initiate innate immunity to express disordered TNF-α or type I IFN resulting in several autoimmune diseases. Cationic polymers have been profoundly proved to alleviate the inflammatory symptoms by removing the debris of cell-free DNA (cfDNA). However, clinical applications of cationic materials have been impeded by concerns of their toxicity and the fate of cfDNA in polymer-cfDNA complex. Herein, it is showed that PEGylated polyimidazoles as a biomimetic DNase potently alleviate pathologic symptoms of self-DNA-associated rheumatoid arthritis (RA) rats and Trex1 (DNase III) deficient Aicardi-Goutiéres syndrome (AGS) mice. The mechanism studies demonstrate that the polyimidazole efficiently attacks the phosphodiester linkages of NAs and cleavages them into small pieces. As imidazole unit is a much weaker organic base that occurs in natural proteins, the polyimidazoles are less toxic to cells and tissues, as manifested by the IC50 values larger than 1000 µg mL−1. This work suggests that synthetic tailored DNase can be a new and safe therapeutic agent to treat chronic autoimmune and refractory inflammatory diseases by degradation of excessive nucleic acids.  相似文献   

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A model to estimate the short‐circuit current of a solar cell under artificial light from the short‐circuit current of the same solar cell under AM1.5 1 kW/m2 is described. The results may help designers of solar‐powered portable equipment and consumer products working indoors or under a mixture of artificial and sunlight. It is concluded that the ratio of the short‐circuit currents of the same solar cell generated under fluorescent light of 1 lux illuminance divided by the short‐circuit current generated under standard 1 Sun AM1.5 conditions is around 3 × 10−6 for typical crystalline silicon and CIS solar cells. This value is one order of magnitude greater if the light source considered is an incandescent lamp. In the case of amorphous silicon solar cells the value of the ratio is close to 8 × 10−6 either for fluorescent or incandescent lamps. CdTe solar cells are also considered, and this factor is about 4 × 10−6 under fluorescent light, and four times bigger when an incandescent lamp is used. Some measurements performed validate the figures obtained. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

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The use of cellular nanovesicles (CNVs) is a groundbreaking innovation in biomedical applications. Both natural extracellular vesicles (EVs) and artificial cell membrane nanovesicles (AVs) have emerged as innovative CNVs, but they have limitations in therapeutic effects and targeting abilities. Challenges such as stability, immunogenicity, and drug payload capacity hinder their widespread application. Genetic engineering has matured as a widely employed modification strategy, leading to the development of genetically engineered extracellular vesicles (gEVs) and genetically engineered artificial cell membrane nanovesicles (gAVs). This review meticulously examines the diverse types and inherent characteristics of CNVs, alongside various surface engineering strategies for CNVs, with a specific focus on elucidating the attributes and detailing the preparation methods relevant to gEVs and gAVs. Furthermore, this exploration delves into the expansive landscape of biomedical applications, developmental prospects, and current challenges associated with the utilization of gEVs and gAVs. With a comprehensive approach, the primary objective is to provide insights that not only illuminate the nuanced intricacies of these nanovesicles but also pave the way for their seamless integration into clinical research and eventual translation into practical applications.  相似文献   

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Here, the use of high-performance microfluidic techniques (HPMT) is reportedto afford conjugated porous polymer (CPPs) with smaller particle size and narrower particle size dispersion than the obtained by miniemulsion methodology. Specifically, polymers based on BODIPY or BOPHY dyes are synthesized by HPMT conditions and conventional miniemulsion conditions. The polymer textural properties from HPMT are notably improved, giving rise to high-quality thin films that are photoelectrochemically characterized. Furthermore, hybrid materials of CPPs synthesized by HPMT and TiO2 inorganic semiconductor revealed enhanced photocatalytic activity in the hydrogen evolution reaction (HER). The most active hybrid UN_IEP-7@T-10 photocatalyst, containing 10 wt% polymer loading, achieved a hydrogen evolution rate of 3.10 mmol g−1 h−1 (ƺ = 1.13%), which is threefold higher than that of its non-nanostructured from bulk synthesis, two-times greater than its nanostructured by conventional miniemulsion techniques and even surpassed by 39-times the performance of bare TiO2. It is noteworthy that both photoluminescence lifetime (τPL) and transient lifetime (τT) are not affected by the nanoestructuration of CPPs, which agrees with the preservation of the chemical structure by both synthetic methodologies. The employment of HPMT as nanostructuration strategy clearly supports the obtaining of more processable polymers for a wide range of energy applications.  相似文献   

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Elucidating the mechanism that differentiates the oxygen‐evolving center of photosystem II with its inorganic counterpart is crucial to develop efficient catalysts for the oxygen evolution reaction (OER). Previous studies have suggested that the larger overpotential for MnO2 catalysts under neutral conditions may result from the instability of the Mn3+ intermediate to charge disproportionation. Here, by monitoring the surface intermediates of electrochemical OER on rutile MnO2 with different facet orientations, a correlation between the stability of the intermediate species and crystal facets is confirmed explicitly for the first time. The coverage of the Mn3+ intermediate is found to be 11‐fold higher on the metastable (101) surfaces compared to (110) surfaces, leading to the superior OER activity of (101) surfaces. The difference in OER activity may result from the difference in surface electronic states of Mn3+, where interlayer charge comproportionation of Mn2+ and Mn4+ to generate two Mn3+ species is favored on (101) facets. Considering the fact that the OER enzyme accommodates Mn3+ stably during the Kok cycle, the enhanced OER activity of the rutile MnO2 catalyst with a metastable surface highlights the importance of mimicking not only the crystal structure but also the electronic structure of the targeted natural enzyme.  相似文献   

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针对战场多源信息融合的典型应用需求,提出了基于人工智能的目标信息融合技术思路,并对其中的两项关键技术,即新型融合知识库构建技术和基于本体核的目标知识融合技术进行了分析,最后对多源信息融合系统在应用过程中存在的技术问题及其解决思路进行了探讨。  相似文献   

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Textile-based wearable electronics provides the combined advantages of both electronics and textiles, such as flexibility, stretchability and lightweight. Much effort has been dedicated to achieve flexible photovoltaic power for wearable electronics. Here, we have demonstrated polypyrrole (PPy) coated cotton fabrics as textile counter electrode (CE) in dye-sensitized solar cells (DSSCs). PPy is deposited on the Ni-coated cotton fabrics as catalytic material by electrochemical polymerization of pyrrole. The highly conductive PPy-coated fabric electrode with a surface resistance of 5.0 Ω sq−1 shows reasonable catalytic activity for the reduction of triiodide ion. The DSSC fabricated with the PPy-coated fabric CE exhibits a power conversion efficiency as high as ∼3.83% under AM 1.5 illumination.  相似文献   

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Understanding the biophysical relationships between stem cells and applied biomaterials can facilitate the ability to control the functions and behaviors of stem cells. However, the role of 3D microenvironment in stem cell biology remains largely unexplored, compared with that of 2D cell-culture environment. Here, a new strategy that improves the efficacy of Yamanaka's four-factor-induced cellular reprogramming into induced pluripotent stem cells (iPSCs) by incorporating cues derived from the 3D microenvironment and biophysical ligands is reported. Among the various 3D hydrogel systems tested, methacrylated hyaluronic acid (HA) hydrogel significantly improves cellular reprogramming into iPSCs. Additionally, the initial upregulation of CD44 in encapsulated cells in low-level methacrylated soft HA hydrogel accelerates the reprogramming. In conclusion, the reported HA hydrogel with low modulus accelerates reprogramming into iPSCs and thus offers potential advantages for translational applications.  相似文献   

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