Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a ...challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi‐epitope chimeric antigen (ChA) and screening two classes of protein‐assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin‐binding protein A of Glaesserella parasuis. Our engineered strain, which co‐expresses P17 tagged‐ChA and endogenous chaperones groEL‐ES, yields a 0.346 g/L highly soluble ChA with the property of HPS‐positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5‐L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.
Chen et al. present a novel strategy to improve soluble form of multi‐epitope chimeric antigen via computer‐assisted strategy and folding elements is developed in this study, which provides potential applications to achieve high soluble expression and productivity of membrane protein antigen against Glaesserella parasuis. By using this strategy, an industrial E. coli recombinant strain capable of efficiently expressing subunit vaccine candidate was obtained.
Interfacial charge collection efficiency has demonstrated significant effects on the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Herein, crystalline phase‐dependent charge ...collection is investigated by using rutile and anatase TiO2 electron transport layer (ETL) to fabricate PSCs. The results show that rutile TiO2 ETL enhances the extraction and transportation of electrons to FTO and reduces the recombination, thanks to its better conductivity and improved interface with the CH3NH3PbI3 (MAPbI3) layer. Moreover, this may be also attributed to the fact that rutile TiO2 has better match with perovskite grains, and less trap density. As a result, comparing with anatase TiO2 ETL, MAPbI3 PSCs with rutile TiO2 ETL delivers significantly enhanced performance with a champion PCE of 20.9 % and a large open circuit voltage (VOC) of 1.17 V.
A rutile TiO2 electron transport layer (ETL) was prepared. The thickness and crystallinity can be controlled by deposition time and sintering temperature. Rutile TiO2 has higher conductivity than anatase for faster electron transfer, better interface contact with the perovskite layer, and a lower trap density. These facilitate the charge extraction and collection and reducing carrier recombination.
Keratin is widely recognized as a high‐quality renewable protein resource for biomedical applications. Despite their extensive existence, keratin resources such as feathers, wool, and hair exhibit ...high stability and mechanical properties because of their high disulfide bond content. Consequently, keratin extraction is challenging and its application is greatly hindered. In this work, a biological extraction strategy is proposed for the preparation of bioactive keratin and the fabrication of self‐assembled keratin hydrogels (KHs). Based on moderate and controlled hydrolysis by keratinase, keratin with a high molecular weight of approximately 45 and 28 kDa that retain its intrinsic bioactivities is obtained. The keratin products show excellent ability to promote cell growth and migration and are conferred with significant antioxidant ability because of their intrinsically high cysteine content. In addition, without the presence of any cross‐linking agent, the extracted keratin can self‐assemble into injectable hydrogels. The KHs exhibit a porous network structure and 3D culture ability, showing potential in promoting wound healing. This enzyme‐driven keratin extraction strategy opens up a new approach for the preparation of keratin that can self‐assemble into injectable hydrogels for biomedical engineering.
This work not only provided a novel ecofriendly method for the extraction of bioactive keratins from wool wastes based on the moderate and controlled hydrolysis of keratinase, but also prepared self‐assembled keratin hydrogels for promoting wound repair. It can help dispose keratin solid contaminants and achieve their high value by recycling as biomaterials.
The electrochemical carbon dioxide reduction reaction (CO2RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the ...different CO2RR pathways, the conversion of CO2 into CO is considered one of the most promising candidate reactions because of its high technological and economic feasibility. Integrating catalyst and electrolyte design with an understanding of the catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we give an overview of recent advances and challenges for the selective conversion of CO2 into CO. Multidimensional catalyst and electrolyte engineering for the CO2RR are also summarized. Furthermore, recent studies on the large‐scale production of CO are highlighted to facilitate industrialization of the electrochemical reduction of CO2. To conclude, the remaining technological challenges and future directions for the industrial application of the CO2RR to generate CO are highlighted.
The selective electrochemical reduction of CO2 to CO provides a promising approach to realize a sustainable, carbon‐neutral economy. This Review gives a comprehensive overview focusing on catalyst and electrolyte design, and their integration with electrolyzer technology towards industrial implementation. The current challenges in the commercial use of CO2 electrolysis to generate CO are also presented to enable future developments.
Electroless deposition via a spontaneous redox reaction between the metal precursor and support is believed to be a promising approach for the syntheses of supported metal nanoparticles (SMNPs). ...However, its widespread applications are significantly prohibited by the low reductivity and high cost of support. To overcome these shortcomings, a porous carbon (PC) is herein developed as a promising matrix for the electroless deposition of metal NPs. Benefiting from abundant oxygen‐based surface functional groups, the PC shows stronger reducibility (low redox potential) than conventional carbon substrate such as carbon nanotubes or graphene oxide, enabling a facile electroless deposition of Ir, Rh, and Ru NPs on its surface. These SMNPs exhibit an impressive electrocatalytic activity for the hydrogen evolution reaction (HER) or hydrogen oxidation reaction (HOR). For example, the Rh NP/PC can deliver an HER current density of 10 mA cm−2 with a small overpotential of 21 mV in 0.5 m H2SO4, while the Ru NP/PC exhibits excellent HOR activity in 0.1 m KOH in terms of high mass and surface specific exchange current density of 263 A g−1Ru and 0.227 mA cm−2Ru. The present strategy may open up opportunities for mass production of efficient supported NPs for diverse applications.
Ultrafine well‐dispersed Ir, Rh, and Ru nanoparticles (NPs) are synthesized by cost‐effective room‐temperature electroless deposition using the support itself as the reducing agent. Rh NP/PC (porous carbon) shows superior hydrogen evolution reaction activity with a small overpotential (21 mV) at 10 mA cm−2 whereas Ru NP/PC exhibits excellent hydrogen oxidation reaction activity in terms of high exchange current density.
Li‐based batteries are a hot research topic because they are the most popular energy storage system for high energy‐density devices. As an important component of the battery, the current collectors ...in both cathode and anode should be well designed. Herein, the design of 3D current collectors for Li‐based batteries is considered, including 3D metal‐based and carbon‐based current collectors. The progress in nanotechnology provides appropriate 3D current collectors characterized by highly efficient morphologies and architectures. In particular, 3D current collectors with different morphology are classified. Critical factors of current collectors that affect the electrochemical performance of Li‐based batteries are comprehensively debated. Finally, conclusion and perspectives of the future research in this field are discussed.
Building up a three‐dimensional current collector can simultaneously optimize the conductive network in the electrochemically active layers and mitigate the volume change during cycling, which leads to enhanced energy density, power density, and cycle stability. Inspiration for further exploitation of the current collectors for Li‐based batteries is given and batteries based on other electrochemistry are considered.
ConspectusHydrogen is an ideal energy carrier and plays a critical role in the future energy transition. Distinct from steam reforming, electrochemical water splitting, especially powered by ...renewables, has been considered as a promising technique for scalable production of high-purity hydrogen with no carbon emission. Its commercialization relies on the reduction of electricity consumption and thus hydrogen cost, calling for highly efficient and cost-effective electrocatalysts with the capability of steadily working at high hydrogen output. This requires the electrocatalysts to feature (1) highly active intrinsic sites, (2) abundant accessible active sites, (3) effective electron and mass transfer, (4) high chemical and structural durability, and (5) low-cost and scalable synthesis. It should be noted that all these requirements should be fulfilled together for a practicable electrocatalyst. Much effort has been devoted to addressing one or a few aspects, especially improving the electrocatalytic activity by electronic modulation of active sites, while few reviews have focused on the synergistic modulation of these aspects together although it is essential for advanced electrochemical water splitting.In this Account, we will present recent innovative strategies with an emphasis on our solutions for synergistically modulating intrinsic active sites, electron transportation, mass transfer, and gas evolution, as well as mechanical and chemical durability, of non-precious-metal electrocatalysts, aiming for cost-effective and highly efficient water splitting. The following approaches for coupling these aspects are summarized for both cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). (1)
. The electronic structure of a catalytic site determines the adsorption/desorption of reactive intermediates and thus intrinsic activity. It can be tuned by heterogeneous doping, strain effect, spin polarization, etc. Coupling these effects to optimize the reaction pathways or target simultaneously the activity and stability would advance electrocatalytic performance. (2)
. The crystallinity, crystalline phase, crystalline facets, crystalline defects, etc. affect both activity and stability. Coupling these effects with electronic modulation would enhance the activity together with stability. (3)
. It will focus on concurrently modulating electronic structure for improving the intrinsic activity and morphology for increasing accessible active sites, especially through single action or processing. The mass transfer and gas evolution properties can also be enhanced by morphological modulation to enable water splitting at large output. (4)
. Electrocatalytic reaction generally consists of a couple of elementary reactions. Each one may need a specific active site. Designing and combining various components targeting every elementary step on a space-limited catalyst surface will balance the intermediates and these steps for accelerating the overall reaction. (5)
Taking all these strategies together into account is necessary to integrate all above essential features into one electrocatalyst for enabling high-output water electrolysis. Beyond the progress made to date, the remaining challenges and opportunities is also discussed. With these insights, hopefully, this Account will shed light on the rational design of practical water-splitting electrocatalysts for the cost-effective and scalable production of hydrogen.
The wind power input to near‐inertial (NI) motions is studied using a global eddy‐permitting ocean general circulation model. The model is forced by high‐ (1‐hourly, at 0.35° resolution) and ...low‐resolution (6‐hourly, at 1.875° resolution) wind data. A change from low‐ to high‐resolution forcing results in an increase in NI kinetic energy by a factor three and raises the wind‐generated power input to NI motions from 0.3 TW to 1.1 TW. Time and space filtering of the wind fields yield less kinetic energy, with a larger drop from time filtering. This strong sensitivity to wind forcing points to a possible underestimation of the wind‐generated energy available for deep ocean mixing in previous studies based on low‐resolution winds.
Key Points
Near‐inertial motions in the ocean are generated by hourly wind forcingTemporal resolution of the winds has a stronger effect than spatial resolutionThe total wind‐induced power input to near‐inertial motions is 1.1 TW
In the last couple of decades, solid-state device technologies, particularly electronic semiconductor devices, have been greatly advanced and investigated for possible adoption in various terahertz ...(THz) applications, such as imaging, security, and wireless communications. In tandem with these investigations, researchers have been exploring ways to package those THz electronic devices and integrated circuits for practical use. Packages are fundamentally expected to provide a physical housing for devices and integrated circuits (ICs) and reliable signal interconnections from the inside to the outside or vice versa. However, as frequency increases, we face several challenges associated with signal loss, dimensions, and fabrication. This paper provides a broad overview of recent progress in interconnections and packaging technologies dealing with these issues for THz electronics. In particular, emerging concepts based on commercial ceramic technologies, micromachining, and 3-D printing technologies for compact and lightweight packaging in practical applications are highlighted, along with metallic split blocks with rectangular waveguides, which are still considered the most valid and reliable approach.
Green and scalable syntheses of highly dispersed supported metal nanocatalysts (SMNCs) are of significant importance for heterogeneous catalysis in industry. In order to achieve nanosized SMNCs and ...prevent metal nanoparticles (NPs) from aggregation, the traditional liquid syntheses commonly require organic capping agents and low metal loading, which are unfavorable for practical production of SMNCs. Herein, a green and facile solid‐state approach is reported for a general synthesis of Rh, Ru, and Ir NPs highly dispersed on different carbon supports via a room‐temperature mortar grinding. The synthesis is easy to scale up and no organic solvent is needed. Metal NPs are free of capping agents and in a couple of nanometers with a uniform size distribution. Benefiting from the above features and high intrinsic activity, Rh NP/C shows the superior activity for hydrogen evolution reaction (HER) in terms of an ultralow overpotential of 7 mV at 10 mA cm−2, outperforming the state‐of‐the‐art HER electrocatalysts. The cell voltage to output a stable current density of 10 mA cm−2 is only 1.53 V for the electrolyzer with Rh NP/C cathode. These results indicate that the present scalable solid‐state synthetic strategy paves a new avenue for mass production of highly efficient SMNCs for diverse applications.
A facile scalable grinding strategy is developed to produce a series of highly dispersed metal nanoparticles (NPs) on various carbon supports. Among them, Rh NPs in ≈2.05 nm shows superior HER activity with an ultralow overpotential of 7 mV at 10 mA cm−2, enabling an efficient electrolyzer with a low cell voltage of 1.53 V at 10 mA cm−2.
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