As a biomaterial, silk presents unique features with a combination of excellent mechanical properties, biocompatibility, and biodegradability. The biodegradability aspects of silk biomaterials, ...especially with options to control the rate from short (days) to long (years) time frames in vivo, make this protein-based biopolymer a good candidate for developing biodegradable devices used for tissue repairs and tissue engineering, as well as medical device implants. Silk materials, including native silk fibers and a broad spectrum of regenerated silk materials, have been investigated in vitro and in vivo to demonstrate degradation by proteolytic enzymes. In this Review, we summarize the findings on these studies on the enzymatic degradation of Bombyx mori (B. mori) silk materials. We also present a discussion on the factors that dictate the degradation properties of silk materials. Finally, in future perspectives, we highlight some key challenges and potential directions toward the future study of the degradation of silk materials.
Targeted genome editing technologies are powerful tools for studying biology and disease, and have a broad range of research applications. In contrast to the rapid development of toolkits to ...manipulate individual genes, large-scale screening methods based on the complete loss of gene expression are only now beginning to be developed. Here we report the development of a focused CRISPR/Cas-based (clustered regularly interspaced short palindromic repeats/CRISPR-associated) lentiviral library in human cells and a method of gene identification based on functional screening and high-throughput sequencing analysis. Using knockout library screens, we successfully identified the host genes essential for the intoxication of cells by anthrax and diphtheria toxins, which were confirmed by functional validation. The broad application of this powerful genetic screening strategy will not only facilitate the rapid identification of genes important for bacterial toxicity but will also enable the discovery of genes that participate in other biological processes.
Silks are natural fibrous protein polymers that are spun by silkworms and spiders. Among silk variants, there has been increasing interest devoted to the silkworm silk of B. mori, due to its ...availability in large quantities along with its unique material properties. Silk fibroin can be extracted from the cocoons of the B. mori silkworm and combined synergistically with other biomaterials to form biopolymer composites. With the development of recombinant DNA technology, silks can also be rationally designed and synthesized via genetic control. Silk proteins can be processed in aqueous environments into various material formats including films, sponges, electrospun mats and hydrogels. The versatility and sustainability of silk-based materials provides an impressive toolbox for tailoring materials to meet specific applications via eco-friendly approaches. Historically, silkworm silk has been used by the textile industry for thousands of years due to its excellent physical properties, such as lightweight, high mechanical strength, flexibility, and luster. Recently, due to these properties, along with its biocompatibility, biodegradability and non-immunogenicity, silkworm silk has become a candidate for biomedical utility. Further, the FDA has approved silk medical devices for sutures and as a support structure during reconstructive surgery. With increasing needs for implantable and degradable devices, silkworm silk has attracted interest for electronics, photonics for implantable yet degradable medical devices, along with a broader range of utility in different device applications. This Tutorial review summarizes and highlights recent advances in the use of silk-based materials in bio-nanotechnology, with a focus on the fabrication and functionalization methods for in vitro and in vivo applications in the field of tissue engineering, degradable devices and controlled release systems.
Hydrogen energy (H2) has been considered as the most possible consummate candidates for replacing the traditional fossil fuels because of its higher combustion heat value and lower environmental ...pollution. Photocatalytic hydrogen evolution (PHE) from water splitting based on semiconductors is a promising technology towards converting solar energy into sustainable H2 fuel evolution. Developing high-activity and abundant source semiconductor materials is particularly important to realize highly efficient hydrogen evolution as for photocatalysis technology. However, unmodified pristine photocatalysts are often unable to overcome the weakness of low performance due to their limitations. In recent years, transition metal phosphides (TMPs) were used as valid co-catalysts to replace the classic precious metal materials in the process of photocatalytic reaction owing to their lower cost and higher combustion heat value. What is more, bimetallic phosphides have been also caused widespread concern in H2 evolution reaction owing to its much lower overpotential, more superior conductivity, and weaker charge carriers transfer impedance in comparison to those of single metal phosphides. In this minireview, we concluded the latest developments of bimetallic phosphides for a series of photocatalytic reactions. Firstly, we briefly summarize the present loading methods of bimetallic phosphides (BMPs) anchored on the photocatalyst. After that, the H2 evolution efficiency based on BMPs as cocatalyst is also studied in detail. Besides, the application of BMPs-based host photocatalyst for H2 evolution under dye sensitization effect has also been discussed. At last, the current development prospects and prospective challenges in many ways of BMPs are proposed. We sincerely hope this minireview has certain reference value for great developments of BMPs in the future research.
Display omitted Bimetallic phosphides have been also caused widespread concern in H2 evolution reaction owing to its unique Advantages. In this minireview, we concluded the latest developments of bimetallic phosphides as cocatalyst for a series of photocatalytic H2 evolution reactions.
Developing high‐efficiency and low‐cost photocatalysts by avoiding expensive noble metals, yet remarkably improving H2 evolution performance, is a great challenge. Noble‐metal‐free catalysts ...containing Co(Fe)NC moieties have been widely reported in recent years for electrochemical oxygen reduction reaction and have also gained noticeable interest for organic transformation. However, to date, no prior studies are available in the literature about the activity of N‐coordinated metal centers for photocatalytic H2 evolution. Herein, a new photocatalyst containing g‐C3N4 decorated with CoP nanodots constructed from low‐cost precursors is reported. It is for the first time revealed that the unique P(δ−)Co(δ+)N(δ−) surface bonding states lead to much superior H2 evolution activity (96.2 µmol h−1) compared to noble metal (Pt)‐decorated g‐C3N4 photocatalyst (32.3 µmol h−1). The quantum efficiency of 12.4% at 420 nm is also much higher than the record values (≈2%) of other transition metal cocatalysts‐loaded g‐C3N4. It is believed that this work marks an important step toward developing high‐performance and low‐cost photocatalytic materials for H2 evolution.
The unique P(δ−)Co(δ+)N(δ−) surface bonding states are constructed by decorating crystalline CoP nanodots on the g‐C3N4 nanosheet, which results in a superior H2 evolution rate of 96.2 µmol h−1 with the highest quantum efficiency value of 12.4% at 420 nm.
Lithium metal (Li0) rechargeable batteries (LMBs), such as systems with a Li0 anode and intercalation and/or conversion type cathode, lithium‐sulfur (Li‐S), and lithium‐oxygen (O2)/air (Li‐O2/air) ...batteries, are becoming increasingly important for electrifying the modern transportation system, with the aim of sustainable mobility. Although some rechargeable LMBs (e.g. Li0/LiFePO4 batteries from Bolloré Bluecar, Li‐S batteries from OXIS Energy and Sion Power) are already commercially viable in niche applications, their large‐scale deployment is hampered by a number of formidable challenges, including growth of lithium dendrites, electrolyte instability towards high voltage intercalation‐type cathodes, the poor electronic and ionic conductivities of sulfur (S8) and O2, as well as their corresponding reduction products (e.g. Li2S and Li2O), dissolution, and shuttling of polysulfide (PS) intermediates. This leads to a short lifecycle, low coulombic/energy efficiency, poor safety, and a high self‐discharge rate. The use of electrolyte additives is considered one of the most economical and effective approaches for circumventing these problems. This Review gives an overview of the various functional additives that are being applied and aims to stimulate new avenues for the practical realization of these appealing devices.
Better batteries: The use of electrolyte additives is considered one of the most viable, economical, and effective approaches to circumvent the problems of rechargeable Li metal batteries (LMBs). This Review assesses the current status of research on electrolyte additives for rechargeable LMBs and considers new avenues for the realization of these appealing devices.
Lithium solid-state batteries (SSBs) are considered as a promising solution to the safety issues and energy density limitations of state-of-the-art lithium-ion batteries. Recently, the possibility of ...developing practical SSBs has emerged thanks to striking advances at the level of materials; such as the discovery of new highly-conductive solid-state electrolytes. Consequently, the focus in research has progressively shifted towards the integration of the various components, the battery's functionality at full cell level, and the scalability of the fabrication processes. Considering these points, the development of SSBs still faces formidable challenges. This review covers the recent advances in SSB development, stressing the importance of full cell integration. The most relevant materials and fabrication processes are briefly summarized and their potential applications in SSBs are examined. The main challenges and strategies for full cell integration are then discussed highlighting the most promising materials and the best suited processing techniques. Particular attention is paid on the mutual compatibility of the cell components, the properties of the interfaces within the cell (anode-electrolyte, cathode-electrolyte, intra-electrolyte) and the strategies applied to stabilize and minimize the resistance of these interfaces via compatible processing.
•Next steps towards solid state batteries.•Potential and most probable candidates as solid electrolytes, cathode active materials.•Challenges to develop electrochemically stable interfaces.•Overview of the existing processing technology for cell production.
A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of ...structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.
COVID-19 has become a global pandemic and there is an urgent call for developing drugs against the virus (SARS-CoV-2). The 3C-like protease (3CL
pro
) of SARS-CoV-2 is a preferred target for broad ...spectrum anti-coronavirus drug discovery. We studied the anti-SARS-CoV-2 activity of S. baicalensis and its ingredients. We found that the ethanol extract of S. baicalensis and its major component, baicalein, inhibit SARS-CoV-2 3CL
pro
activity in vitro with IC
50
's of 8.52 µg/ml and 0.39 µM, respectively. Both of them inhibit the replication of SARS-CoV-2 in Vero cells with EC
50
's of 0.74 µg/ml and 2.9 µM, respectively. While baicalein is mainly active at the viral post-entry stage, the ethanol extract also inhibits viral entry. We further identified four baicalein analogues from other herbs that inhibit SARS-CoV-2 3CL
pro
activity at µM concentration. All the active compounds and the S. baicalensis extract also inhibit the SARS-CoV 3CL
pro
, demonstrating their potential as broad-spectrum anti-coronavirus drugs.
The effect of three different drying methods (hot-air, combined hot-air-microwave, and vacuum-freeze) on the sensorial, textural, nutritional, and other quality characteristics of persimmon chips was ...compared. The result showed that the freeze-dried chips had the best nutritional and quality features. However, persimmon chips processed by combined hot-air-microwave and freeze-techniques had the same sensory score (85.40 points), which were higher than that of hot-air dried samples (70.51 points). Additionally, persimmon chips dried with aid of hot-air technique had the lowest chewability value and hardly met the panelists' requirements. These disadvantages could be avoided by using a combined hot-air-microwave drying method with lower power consumption compared with the others. The optimized combining microwave and hot-air drying conditions were as follows: 1 mm thickness of persimmon slice, a temperature of 70 °C at an air velocity of 1.0 m/s of initial hot-air drying system until the moisture content of persimmon samples reached 10% (about 150–160 min) and 10.7 Wg−1 of the following microwave-drying system. It was concluded that the combined hot-air-microwave drying technique could be used for processing persimmon chips with high quality and nutritional values as well as low operating costs.
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