Chem & Bio Engineering最新文献

Many biological disciplines rely upon the transformation of host cells with heterologous DNA to edit, engineer, or examine biological phenotypes. Transformation of model cell strains (Escherichia coli) under model conditions (electroporation of circular supercoiled plasmid DNA; typically pUC19) can achieve >10¹⁰ transformants/μg DNA. Yet outside of these conditions, e.g., work with relaxed plasmid DNA from in vitro assembly reactions (cloned DNA) or nonmodel organisms, the efficiency of transformation can drop by multiple orders of magnitude. Overcoming these inefficiencies requires cost- and time-intensive processes, such as generating large quantities of appropriately formatted input DNA or transforming many aliquots of cells in parallel. We sought to simplify the generation of large quantities of appropriately formatted input cloned DNA by using rolling circle amplification (RCA) and treatment with specific endonucleases to generate an efficiently transformable linear DNA product for in vivo circularization in host cells. We achieved an over 6500-fold increase in the yield of input DNA, and demonstrate that the use of a nicking endonuclease to generate homologous single-stranded ends increases the efficiency of E. coli chemical transformation compared to both linear DNA with double-stranded homologous ends and circular Golden-Gate assembly products. Meanwhile, the use of a restriction endonuclease to generate linear DNA with double-stranded homologous ends increases the efficiency of chemical and electrotransformation of Saccharomyces cerevisiae. Importantly, we also optimized the process such that both RCA and endonuclease treatment occur efficiently in the same buffer, streamlining the workflow and reducing product loss through purification steps. We expect that our approach could have utility beyond E. coli and S. cerevisiae and be applicable to areas such as directed evolution, genome engineering, and the manipulation of alternative organisms with even poorer transformation efficiencies.

Many biological disciplines rely upon the transformation of host cells with heterologous DNA to edit, engineer, or examine biological phenotypes. Transformation of model cell strains (Escherichia coli) under model conditions (electroporation of circular supercoiled plasmid DNA; typically pUC19) can achieve >10¹⁰ transformants/μg DNA. Yet outside of these conditions, e.g., work with relaxed plasmid DNA from in vitro assembly reactions (cloned DNA) or nonmodel organisms, the efficiency of transformation can drop by multiple orders of magnitude. Overcoming these inefficiencies requires cost- and time-intensive processes, such as generating large quantities of appropriately formatted input DNA or transforming many aliquots of cells in parallel. We sought to simplify the generation of large quantities of appropriately formatted input cloned DNA by using rolling circle amplification (RCA) and treatment with specific endonucleases to generate an efficiently transformable linear DNA product for in vivo circularization in host cells. We achieved an over 6500-fold increase in the yield of input DNA, and demonstrate that the use of a nicking endonuclease to generate homologous single-stranded ends increases the efficiency of E. coli chemical transformation compared to both linear DNA with double-stranded homologous ends and circular Golden-Gate assembly products. Meanwhile, the use of a restriction endonuclease to generate linear DNA with double-stranded homologous ends increases the efficiency of chemical and electrotransformation of Saccharomyces cerevisiae. Importantly, we also optimized the process such that both RCA and endonuclease treatment occur efficiently in the same buffer, streamlining the workflow and reducing product loss through purification steps. We expect that our approach could have utility beyond E. coli and S. cerevisiae and be applicable to areas such as directed evolution, genome engineering, and the manipulation of alternative organisms with even poorer transformation efficiencies.

Copper-based catalysts have been widely used in the field of the nitrate reduction reaction (NO₃RR) to ammonia, demonstrating high nitrate reduction rates. However, their low selectivity for ammonia production poses significant limitations in practical applications. In this study, we present that the incorporation of Ru into the Cu@Ni foam can achieve nearly 100% selectivity for NH₃ and a high faradaic efficiency of 96.8% in the NO₃RR. Ru not only facilitates the generation of adsorbed hydrogen but also suppresses the HER reaction. This can be attributed to the unique electron distribution exhibited by Ru atoms when surrounded by Cu, leading to a decreased electron-accepting capability. Consequently, this reduction results in a diminished Lewis acidity and a decreased H* adsorption. Importantly, it was confirmed that the incorporation of Cu with Ru serves as “anchor” for atomic H* generated from Ru, inhibiting HER and ensuring the availability of H* for subsequent ammonia production. The synergistic effect between Ru and Cu enhanced the efficiency and selectivity of reduction of nitrate to NH₃. Remarkably, substituting oxygen evolution reaction (OER) with a coupled anodic reaction for the oxidation of benzyl alcohol to benzaldehyde can significantly accelerate the nitrate reduction rate by 1.7 times and achieves a 90% benzaldehyde conversion rate. This research not only introduces innovative strategies for designing high-performance ammonia-selective electrocatalysts but also highlights the potential industrial applications for the synthesis of high-value products.

Copper-based catalysts have been widely used in the field of the nitrate reduction reaction (NO₃RR) to ammonia, demonstrating high nitrate reduction rates. However, their low selectivity for ammonia production poses significant limitations in practical applications. In this study, we present that the incorporation of Ru into the Cu@Ni foam can achieve nearly 100% selectivity for NH₃ and a high faradaic efficiency of 96.8% in the NO₃RR. Ru not only facilitates the generation of adsorbed hydrogen but also suppresses the HER reaction. This can be attributed to the unique electron distribution exhibited by Ru atoms when surrounded by Cu, leading to a decreased electron-accepting capability. Consequently, this reduction results in a diminished Lewis acidity and a decreased H* adsorption. Importantly, it was confirmed that the incorporation of Cu with Ru serves as "anchor" for atomic H* generated from Ru, inhibiting HER and ensuring the availability of H* for subsequent ammonia production. The synergistic effect between Ru and Cu enhanced the efficiency and selectivity of reduction of nitrate to NH₃. Remarkably, substituting oxygen evolution reaction (OER) with a coupled anodic reaction for the oxidation of benzyl alcohol to benzaldehyde can significantly accelerate the nitrate reduction rate by 1.7 times and achieves a 90% benzaldehyde conversion rate. This research not only introduces innovative strategies for designing high-performance ammonia-selective electrocatalysts but also highlights the potential industrial applications for the synthesis of high-value products.

The Langmuir isotherm is used to determine the properties of a theoretical "holy grail" adsorbent that can meet the US Department of Energy's methane storage target of 0.5 g/g and 266 v/v. For a storage tank operating between 5 and 65 bar, the adsorbent requires a maximum adsorption capacity of 0.8388 g/g, a binding affinity of 0.05547 bar^-1, and a material density of 377 g/L. For a tank operating between 5 and 80 bar, the binding affinity should be 0.05 bar^-1, with the same capacity and density. The Langmuir isotherm is also applied to calculate the necessary adsorbent properties, including the number of adsorption sites and binding energies, to achieve the volumetric storage target of 266 v/v based on the material's density.

The Langmuir isotherm is used to determine the properties of a theoretical “holy grail” adsorbent that can meet the US Department of Energy’s methane storage target of 0.5 g/g and 266 v/v. For a storage tank operating between 5 and 65 bar, the adsorbent requires a maximum adsorption capacity of 0.8388 g/g, a binding affinity of 0.05547 bar^–1, and a material density of 377 g/L. For a tank operating between 5 and 80 bar, the binding affinity should be 0.05 bar^–1, with the same capacity and density. The Langmuir isotherm is also applied to calculate the necessary adsorbent properties, including the number of adsorption sites and binding energies, to achieve the volumetric storage target of 266 v/v based on the material’s density.

Metal–organic frameworks (MOFs) are promising adsorbents for CO₂ capture due to readily tunable porosity and diverse functionality; however, their performance is deteriorated by the presence of H₂O in a flue gas. Fluorinated MOFs (FMOFs) may impede H₂O interaction with frameworks and enhance CO₂ adsorption under humid conditions. In this study, a multiscale computational screening study is reported to identify the top FMOFs for CO₂ capture from a wet flue gas. Initially, geometric properties as well as heats of H₂O adsorption are used to shortlist FMOFs with a suitable pore size and weak H₂O affinity. Then, grand-canonical Monte Carlo simulations are conducted for adsorption of a CO₂/N₂/H₂O mixture with 60% relative humidity in 5061 FMOFs. Based on the adsorption performance, 19 FMOFs are identified as top candidates. It is revealed that the position of F atom, rather than the amount, affects CO₂ adsorption; moreover, N-decorated FMOFs are preferential for selective CO₂ adsorption. Finally, the hydrostability of the top FMOFs is confirmed by first-principles molecular dynamics simulations. From a microscopic level, this study provides quantitative structure–performance relationships, discovers hydrostable FMOFs with high CO₂ capture performance from a wet flue gas, and would facilitate the development of new MOFs toward efficient CO₂ capture under humid conditions.

Metal-organic frameworks (MOFs) are promising adsorbents for CO₂ capture due to readily tunable porosity and diverse functionality; however, their performance is deteriorated by the presence of H₂O in a flue gas. Fluorinated MOFs (FMOFs) may impede H₂O interaction with frameworks and enhance CO₂ adsorption under humid conditions. In this study, a multiscale computational screening study is reported to identify the top FMOFs for CO₂ capture from a wet flue gas. Initially, geometric properties as well as heats of H₂O adsorption are used to shortlist FMOFs with a suitable pore size and weak H₂O affinity. Then, grand-canonical Monte Carlo simulations are conducted for adsorption of a CO₂/N₂/H₂O mixture with 60% relative humidity in 5061 FMOFs. Based on the adsorption performance, 19 FMOFs are identified as top candidates. It is revealed that the position of F atom, rather than the amount, affects CO₂ adsorption; moreover, N-decorated FMOFs are preferential for selective CO₂ adsorption. Finally, the hydrostability of the top FMOFs is confirmed by first-principles molecular dynamics simulations. From a microscopic level, this study provides quantitative structure-performance relationships, discovers hydrostable FMOFs with high CO₂ capture performance from a wet flue gas, and would facilitate the development of new MOFs toward efficient CO₂ capture under humid conditions.

Extracellular vesicles (EVs) are secreted from biological cells and contain many molecules with diagnostic values or therapeutic functions. There has been great interest in academic and industrial communities to utilize EVs as tools for diagnosis or therapeutics. In addition, EVs can also serve as delivery vehicles for therapeutic molecules. An indicator of the enormous interest in EVs is the large number of review articles published on EVs, with the focus ranging from their biology to their applications. An emerging trend in EV research is to produce and utilize "engineered EVs", which are essentially the enhanced version of EVs. EV engineering can be conducted by cell culture condition control, genetic engineering, or chemical engineering. Given their nanometer-scale sizes and therapeutic potentials, engineered EVs are an emerging class of nanomedicines. So far, an overwhelming majority of the research on engineered EVs is preclinical studies; there are only a very small number of reported clinical trials. This Review focuses on engineered EVs, with a more specific focus being their applications in therapeutics. The various approaches to producing engineered EVs and their applications in various diseases are reviewed. Furthermore, in vivo imaging of EVs, the mechanistic understandings, and the clinical translation aspects are discussed. The discussion is primarily on preclinical studies while briefly mentioning the clinical trials. With continued interdisciplinary research efforts from biologists, pharmacists, physicians, bioengineers, and chemical engineers, engineered EVs could become a powerful solution for many major diseases such as neurological, immunological, and cardiovascular diseases.

Extracellular vesicles (EVs) are secreted from biological cells and contain many molecules with diagnostic values or therapeutic functions. There has been great interest in academic and industrial communities to utilize EVs as tools for diagnosis or therapeutics. In addition, EVs can also serve as delivery vehicles for therapeutic molecules. An indicator of the enormous interest in EVs is the large number of review articles published on EVs, with the focus ranging from their biology to their applications. An emerging trend in EV research is to produce and utilize “engineered EVs”, which are essentially the enhanced version of EVs. EV engineering can be conducted by cell culture condition control, genetic engineering, or chemical engineering. Given their nanometer-scale sizes and therapeutic potentials, engineered EVs are an emerging class of nanomedicines. So far, an overwhelming majority of the research on engineered EVs is preclinical studies; there are only a very small number of reported clinical trials. This Review focuses on engineered EVs, with a more specific focus being their applications in therapeutics. The various approaches to producing engineered EVs and their applications in various diseases are reviewed. Furthermore, in vivo imaging of EVs, the mechanistic understandings, and the clinical translation aspects are discussed. The discussion is primarily on preclinical studies while briefly mentioning the clinical trials. With continued interdisciplinary research efforts from biologists, pharmacists, physicians, bioengineers, and chemical engineers, engineered EVs could become a powerful solution for many major diseases such as neurological, immunological, and cardiovascular diseases.