Mobile genetic element-based gene editing and genome engineering: Recent advances and applications.

Genome engineering has revolutionized several scientific fields, ranging from biochemistry and fundamental research to therapeutic uses and crop development. Diverse engineering toolkits have been developed and used to effectively modify the genome sequences of organisms. However, there is a lack of extensive reviews on genome engineering technologies based on mobile genetic elements (MGEs), which induce genetic diversity within host cells by changing their locations in the genome. This review provides a comprehensive update on the versatility of MGEs as powerful genome engineering tools that offers efficient solutions to challenges associated with genome engineering. MGEs, including DNA transposons, retrotransposons, retrons, and CRISPR-associated transposons, offer various advantages, such as a broad host range, genome-wide mutagenesis, efficient large-size DNA integration, multiplexing capabilities, and in situ single-stranded DNA generation. We focused on the components, mechanisms, and features of each MGE-based tool to highlight their cellular applications. Finally, we discussed the current challenges of MGE-based genome engineering and provided insights into the evolving landscape of this transformative technology. In conclusion, the combination of genome engineering with MGE demonstrates remarkable potential for addressing various challenges and advancing the field of genetic manipulation, and promises to revolutionize our ability to engineer and understand the genomes of diverse organisms.

Lattice-Oxygen-Stabilized Li- and Mn-Rich Cathodes with Sub-Micrometer Particles by Modifying the Excess-Li Distribution.

In recent years, Li- and Mn-rich layered oxides (LMRs) have been vigorously explored as promising cathodes for next-generation, Li-ion batteries due to their high specific energy. Nevertheless, their actual implementation is still far from a reality since the trade-off relationship between the particle size and chemical reversibility prevents LMRs from achieving a satisfactory, industrial energy density. To solve this material dilemma, herein, a novel morphological and structural design is introduced to Li1.11 Mn0.49 Ni0.29 Co0.11 O2 , reporting a sub-micrometer-level LMR with a relatively delocalized, excess-Li system. This system exhibits an ultrahigh energy density of 2880 Wh L-1 and a long-lasting cycle retention of 83.1% after the 100th cycle for 45 °C full-cell cycling, despite its practical electrode conditions. This outstanding electrochemical performance is a result of greater lattice-oxygen stability in the delocalized excess-Li system because of the low amount of highly oxidized oxygen ions. Geometric dispersion of the labile oxygen ions effectively suppresses oxygen evolution from the lattice when delithiated, eradicating the rapid energy degradation in a practical cell system.

Boosting Reaction Homogeneity in High-Energy Lithium-Ion Battery Cathode Materials.

Conventional nickel-rich cathode materials suffer from reaction heterogeneity during electrochemical cycling particularly at high temperature, because of their polycrystalline properties and secondary particle morphology. Despite intensive research on the morphological evolution of polycrystalline nickel-rich materials, its practical investigation at the electrode and cell levels is still rarely discussed. Herein, an intrinsic limitation of polycrystalline nickel-rich cathode materials in high-energy full-cells is discovered under industrial electrode-fabrication conditions. Owing to their highly unstable chemo-mechanical properties, even after the first cycle, nickel-rich materials are degraded in the longitudinal direction of the high-energy electrode. This inhomogeneous degradation behavior of nickel-rich materials at the electrode level originates from the overutilization of active materials on the surface side, causing a severe non-uniform potential distribution during long-term cycling. In addition, this phenomenon continuously lowers the reversibility of lithium ions. Consequently, considering the degradation of polycrystalline nickel-rich materials, this study suggests the adoption of a robust single-crystalline LiNi0.8 Co0.1 Mn0.1 O2 as a feasible alternative, to effectively suppress the localized overutilization of active materials. Such an adoption can stabilize the electrochemical performance of high-energy lithium-ion cells, in which superior capacity retention above ≈80% after 1000 cycles at 45 °C is demonstrated.

Excess-Li Localization Triggers Chemical Irreversibility in Li- and Mn-Rich Layered Oxides.

Li- and Mn-rich layered oxides (LMRs) have emerged as practically feasible cathode materials for high-energy-density Li-ion batteries due to their extra anionic redox behavior and market competitiveness. However, sluggish kinetics regions (<3.5 V vs Li/Li+ ) associated with anionic redox chemistry engender LMRs with chemical irreversibility (first-cycle irreversibility, poor rate properties, voltage fading), which limits their practical use. Herein, the structural origin of this chemical irreversibility is revealed through a comparative study involving Li1.15 Mn0.51 Co0.17 Ni0.17 O2 with relatively localized and delocalized excess-Li in its lattice system. Operando fine-interval X-ray absorption spectroscopy is used to simultaneously observe the interplay between transition-metal-oxygen (TM-O) redox chemistry and TM migration behavior in real time. Density functional theory calculations show that excess-Li localization in the LMR structure attenuates TM-O covalency and stability, leading to overall chemical irreversibility. Hence, the delocalized excess-Li system is proposed as an alternative design for practically feasible LMR cathodes with restrained TM migration and sustainable O-redox chemistry.

Tools and systems for evolutionary engineering of biomolecules and microorganisms.

Evolutionary approaches have been providing solutions to various bioengineering challenges in an efficient manner. In addition to traditional adaptive laboratory evolution and directed evolution, recent advances in synthetic biology and fluidic systems have opened a new era of evolutionary engineering. Synthetic genetic circuits have been created to control mutagenesis and enable screening of various phenotypes, particularly metabolite production. Fluidic systems can be used for high-throughput screening and multiplexed continuous cultivation of microorganisms. Moreover, continuous directed evolution has been achieved by combining all the steps of evolutionary engineering. Overall, modern tools and systems for evolutionary engineering can be used to establish the artificial equivalent to natural evolution for various research applications.

Understanding voltage decay in lithium-excess layered cathode materials through oxygen-centred structural arrangement.

Lithium-excess 3d-transition-metal layered oxides (Li1+xNiyCozMn1-x-y-zO2, >250 mAh g-1) suffer from severe voltage decay upon cycling, which decreases energy density and hinders further research and development. Nevertheless, the lack of understanding on chemical and structural uniqueness of the material prevents the interpretation of internal degradation chemistry. Here, we discover a fundamental reason of the voltage decay phenomenon by comparing ordered and cation-disordered materials with a combination of X-ray absorption spectroscopy and transmission electron microscopy studies. The cation arrangement determines the transition metal-oxygen covalency and structural reversibility related to voltage decay. The identification of structural arrangement with de-lithiated oxygen-centred octahedron and interactions between octahedrons affecting the oxygen stability and transition metal mobility of layered oxide provides the insight into the degradation chemistry of cathode materials and a way to develop high-energy density electrodes.