Biological Renewable Cellulose-Templated Zn1-XCuXO/Ag2O Nanocomposite Photocatalysts for the Degradation of Methylene Blue.

Herein, Cellulose-templated Zn1-XCuXO/Ag2O nanocomposites were prepared using biological renewable cellulose extracted from water hyacinth (Eichhornia crassipes). Cellulose-templated Cu-doped ZnO catalysts with different amounts of Cu as the dopants (1, 2, 3, and 4%) were prepared and denoted CZ-1, CZ-2, CZ-3, and CZ-4, respectively, for simplicity. The prepared catalysts were tested for the degradation of methylene blue (MB), and 2% Cu-doped ZnO (CZ-2) showed the best catalytic performance (82%), while the pure ZnO, CZ-1, CZ-3, and CZ-4 catalysts exhibited MB dye degradation efficiencies of 54, 63, 65, and 60%, respectively. The best catalyst (CZ-2) was chosen to further improve the degradation efficiency. Different amounts of AgNO3 (10, 15, 30, and 45 mg) were used for the deposition of Ag2O on the surface of CZ-2 and denoted CZA-10, CZA-15, CZA-30, and CZA-45, respectively. Among the composite catalysts, CZA-15 showed remarkable degradation efficiency and degraded 94% of MB, while the CZA-10, CZA-30, and CZA-45 catalysts showed 90, 81, and 79% degradation efficiencies, respectively, under visible light within 100 min of irradiation. The enhanced catalytic performance could be due to the smaller particle size, the higher electron and hole separation and charge transfer efficiencies, and the lower agglomeration in the composite catalyst system. The results also demonstrated that the Cu-doped ZnO prepared with cellulose as a template, followed by the optimum amount of Ag2O deposition, could have promising applications in the degradation of organic pollutants.

Unveiling Advancements: Trends and Hotspots of Metal-Organic Frameworks in Photocatalytic CO2 Reduction.

Metal-organic frameworks (MOFs) are robust, crystalline, and porous materials featured by their superior CO2 adsorption capacity, tunable energy band structure, and enhanced photovoltaic conversion efficiency, making them highly promising for photocatalytic CO2 reduction reaction (PCO2RR). This study presents a comprehensive examination of the advancements in MOFs-based PCO2RR field spanning the period from 2011 to 2023. Employing bibliometric analysis, the paper scrutinizes the widely adopted terminology and citation patterns, elucidating trends in publication, leading research entities, and the thematic evolution within the field. The findings highlight a period of rapid expansion and increasing interdisciplinary integration, with extensive international and institutional collaboration. A notable emphasis on significant research clusters and key terminologies identified through co-occurrence network analysis, highlighting predominant research on MOFs such as UiO, MIL, ZIF, porphyrin-based MOFs, their composites, and the hybridization with photosensitizers and molecular catalysts. Furthermore, prospective design approaches for catalysts are explored, encompassing single-atom catalysts (SACs), interfacial interaction enhancement, novel MOF constructions, biocatalysis, etc. It also delves into potential avenues for scaling these materials from the laboratory to industrial applications, underlining the primary technical challenges that need to be overcome to facilitate the broader application and development of MOFs-based PCO2RR technologies.

UiO-66(Zr) as drug delivery system for non-steroidal anti-inflammatory drugs.

The toxicity for the human body of non-steroidal anti-inflammatory drugs (NSAIDs) overdoses is a consequence of their low water solubility, high doses, and facile accessibility to the population. New drug delivery systems (DDS) are necessary to overcome the bioavailability and toxicity related to NSAIDs. In this context, UiO-66(Zr) metal-organic framework (MOF) shows high porosity, stability, and load capacity, thus being a promising DDS. However, the adsorption and release capability for different NSAIDs is scarcely described. In this work, the biocompatible UiO-66(Zr) MOF was used to study the adsorption and release conditions of ibuprofen, naproxen, and diclofenac using a theoretical and experimental approximation. DFT results showed that the MOF-drug interaction was due to an intermolecular hydrogen bond between protons of the groups in the defect sites, (µ3 - OH, and - OH2) and a lone pair of oxygen carboxyl functional group of the NSAIDs. Also, the experimental results suggest that the solvent where the drug is dissolved affects the adsorption process. The adsorption kinetics are similar between the drugs, but the maximum load capacity differs for each drug. The release kinetics assay showed a solvent dependence kinetics whose maximum liberation capacity is affected by the interaction between the drug and the material. Finally, the biological assays show that none of the systems studied are cytotoxic for HMVEC. Additionally, the wound healing assay suggests that the UiO-66(Zr) material has potential application on the wound healing process. However, further studies should be done.

Hierarchical Porous Bimetallic FeMn Metal-Organic Framework Gel for Efficient Activation of Peracetic Acid in Antibiotic Degradation.

Effective techniques for eliminating antibiotics from water environments are in high demand. The peracetic acid (PAA)-based advanced oxidation process has recently drawn increasing attention for its effective antibiotic degrading capability. However, current applications of PAA-based techniques are limited and tend to have unsatisfactory performance. An additional catalyst for PAA activation could provide a promising solution to improve the performance of PAA. Bulky metal-organic framework gels (MOGs) stand out as ideal catalysts for PAA activation owing to their multiple advantages, including large surface areas, high porosity, and hierarchical pore systems. Herein, a bimetallic hierarchical porous structure, i.e., FeMn13BTC, was synthesized through a facile one-pot synthesis method and employed for PAA activation in ofloxacin (OFX) degradation. The optimized FeMn MOG/PAA system exhibited efficient catalytic performance, characterized by 81.85% OFX degradation achieved within 1 h owing to the specific hierarchical structure and synergistic effect between Fe and Mn ions, which greatly exceeded the performance of the only PAA-catalyzed system. Furthermore, the FeMn MOG/PAA system maintained >80% OFX degradation in natural water. Quenching experiments, electron spin resonance spectra, and model molecular degradation revealed that the primary reactive oxygen species responsible for the catalytic effect was R-O•, especially CH3C(=O)OO•, with minor contributions of •OH and 1O2. Overall, introduction of the MOG catalyst strategy for PAA activation achieved high antibiotic degradation performance, establishing a paradigm for the design of heterogeneous hierarchical systems to broaden the scope of catalyzed water treatment applications.

Gamma irradiation induced degradation of organic pollutants: Recent advances and future perspective.

Different organic compounds in aquatic bodies have been recognized as an emerging issue in Environmental Chemistry. The gamma irradiation technique, as one of the advanced oxidation techniques, has been widely investigated in past decades as a technique for the degradation of organic molecules, such as dyes, pesticides, and pharmaceuticals, which show high persistence to degradation. This review gives an overview of what has been achieved so far using gamma irradiation for different organic compound degradations giving an explanation of the mechanisms of degradations as well as the corresponding limitations and drawbacks, and the answer to why this technique has not yet widely come to life. Also, a new approach, recently presented in the literature, regards coupling gamma irradiation with other techniques and materials, as the latest trend. A critical evaluation of the most recent advances achieved by coupling gamma irradiation with other methods and/or materials, as well as describing the reaction mechanisms of coupling, that is, additional destabilization of molecules achieved by coupling, emphasizing the advantages of the newly proposed approach. Finally, it was concluded what are the perspectives and future directions towards its commercialization since this technique can contribute to waste minimization i.e. not waste transfer to other media. Summarizing and generalization the model of radiolytic degradation with and without coupling with other techniques can further guide designing a new modular, mobile method that will satisfy all the needs for its wide commercial application.

Photocatalytic activity of the biogenic mediated green synthesized CuO nanoparticles confined into MgAl LDH matrix.

The global concern over water pollution caused by organic pollutants such as methylene blue (MB) and other dyes has reached a critical level. Herein, the Allium cepa L. peel extract was utilized to fabricate copper oxide (CuO) nanoparticles. The CuO was combined with MgAl-layered double hydroxides (MgAl-LDHs) via a co-precipitation method with varying weight ratios of the CuO/LDHs. The composite catalysts were characterized and tested for the degradation of MB dye. The CuO/MgAl-LDH (1:2) showed the highest photocatalytic performance and achieved 99.20% MB degradation. However, only 90.03, 85.30, 71.87, and 35.53% MB dye was degraded with CuO/MgAl-LDHs (1:1), CuO/MgAl-LDHs (2:1), CuO, and MgAl-LDHs catalysts, respectively. Furthermore, a pseudo-first-order rate constant of the CuO/MgAl-LDHs (1:2) was 0.03141 min-1 while the rate constants for CuO and MgAl-LDHs were 0.0156 and 0.0052 min-1, respectively. The results demonstrated that the composite catalysts exhibited an improved catalytic performance than the pristine CuO and MgAl-LDHs. The higher photocatalytic performances of composite catalysts may be due to the uniform distribution of CuO nanoparticles into the LDH matrix, the higher surface area, and the lower electron and hole recombination rates. Therefore, the CuO/MgAl-LDHs composite catalyst can be one of the candidates used in environmental remediation.

Recent progress on plant extract-mediated biosynthesis of ZnO-based nanocatalysts for environmental remediation: Challenges and future outlooks.

The plant extract mediated green synthesis of nanomaterials has attracts enormous interest due to its cost-effectiveness, greener, and environmentally friendly. It is also considered as an alternative and facile method in which the phytochemicals can be used as a natural capping and reducing agents and helped to produce nanomaterials with high surface area, different sizes, and shapes. One of the materials fabricated using green methods is zinc oxide (ZnO) semiconductor due to its enormous applications in different field areas. In this review, an overview of recent progress on green synthesized ZnO-based catalysts and various modification methods for the purpose of enhancing the catalytic activity of ZnO and the corresponding structural-activity and interactions towards the removal of pollutants are highlighted. Particularly, the plant extract mediated ZnO-based photocatalysts application for the removal of pollutants via photocatalytic degradation, reduction reaction, and adsorption mechanism are demonstrated. Besides, the opportunities, challenges, and future outlooks of ZnO-based materials for environmental remediation with green and sustainable methods are also included. We believe that this review is a timely and comprehensive review on the recent progress related to plant extract mediated ZnO-based nanocatalysts synthesis and applications for environmental remediation.

Improved stability and activity of laccase through de novo and post-synthesis immobilization on a hierarchically porous metal-organic framework (ZIF-8).

Porous materials such as metal-organic frameworks (MOFs) are considered to be suitable materials for immobilizing enzymes to improve their stability. However, conventional MOFs reduce the enzymes' catalytic activity due to difficulties with mass transfer and diffusing reactants after their micropores are occupied by enzyme molecules. To address these issues, a novel hierarchically structured zeolitic imidazolate framework-8 (HZIF-8) was prepared to study the effects of different laccase immobilization approaches such as the post-synthesis (LAC@HZIF-8-P) and de novo (LAC@HZIF-8-D) immobilization of catalytic activities for removing 2,4-dichlorophenol (2,4-DCP). The results showed higher catalytic activity for the laccase-immobilized LAC@HZIF-8 prepared using different methods than for the LAC@MZIF-8 sample, with 80% of 2,4-DCP removed under optimal conditions. These results could be attributable to the multistage structure of HZIF-8. The LAC@HZIF-8-D sample was stable and superior to LAC@HZIF-8-P, maintaining a 2,4-DCP removal efficiency of 80% after three recycles and demonstrating superior laccase thermostability and storage stability. Moreover, after loading with copper nanoparticles, the LAC@HZIF-8-D approach exhibited a 2,4-DCP removal efficiency of 95%, a promising finding for its potential use in environmental purification.

Sequential Sol-Gel Self-Assembly and Nonclassical Gel-Crystal Transformation of the Metal-Organic Framework Gel.

Metal-organic framework (MOF) gel, an emerging subtype of MOF structure, is unique in formation and function; however, its evolutionary process remains elusive. Here, the evolution of a model gel-based MOF, UiO-66(Zr) gel, is explored by demonstrating its sequential sol-gel self-assembly and nonclassical gel-crystal transformation. The control of the sol-gel process enables the observation and characterization of structures in each assembly stage (phase-separation, polycondensation, and hindered-crystallization) and facilitates the preparation of hierarchical materials with giant mesopores. The gelation mechanism is tentatively attributed to the formation of zirconium oligomers. By further utilizing the pre-synthesized gel, the nonclassical gel-crystal transformation is achieved by the modulation in an unconventional manner, which sheds light on crystal intermediates and distinct crystallization motions ("growth and splitting" and "aggregation and fusion"). The overall sol-gel and gel-crystal evolutions of UiO-66(Zr) enrich self-assembly and crystallization domains, inspire the design of functional structures, and demand more in-depth research on the intermediates in the future.

Prominin 1 Significantly Correlated with Bone Metastasis of Breast Cancer and Influenced the Patient's Prognosis.

Background: This study is aimed at identifying the important biomarkers associated with bone metastasis (BM) in breast cancer (BRCA). Methods: The GSE175692 dataset was used to detect significant differential expressed genes (DEGs) between BRCA samples with or without BM, and DEG-related pathways were then explored. Further, we constructed the protein-protein interaction (PPI) network on GEGs and filtered 5 vital nodes. We then performed the Cox regression, Kaplan-Meier analysis, nomogram, and ROC curve to filter the most significant prognosis genes. The GSE14020 and GSE124647 datasets were used to verify the expression and prognostic value of hub genes, respectively. Finally, the gene set enrichment analysis (GSEA) was performed to reveal the potential mechanism. Results: Totally, 74 DEGs were detected, which mainly correlated with infectious disease, signaling molecules, and interaction. The 5 important DEGs were then filtered, and the Cox regression further showed that 2 genes, including prominin 1 (PROM1) and C-C motif chemokine ligand 2 (CCL2), were related to the prognosis of BRCA metastasis patients. Especially, PROM1 presented a better prognostic performance on the survival probability of patients than CCL2. Verification analysis further confirmed the abnormal expression and significant prognostic influence of PROM1. Finally, GSEA revealed that PROM1 was negatively related to IGF1 and mTOR pathways in BRCA metastasis. Conclusion: PROM1 was an important biomarker associated with BRCA bone metastasis and affected the prognosis of metastatic BRCA patients. It may play a vital role in metastatic BRCA by negatively regulating IGF1 and mTOR pathways.

A Showcase of Green Chemistry: Sustainable Synthetic Approach of Zirconium-Based MOF Materials.

Zirconium-based metal-organic framework materials (Zr-MOFs) have more practical usage over most conventional benchmark porous materials and even many other MOFs due to the excellent structural stability, rich coordination forms, and various active sites. However, their mass-production and application are restricted by the high-cost raw materials, complex synthesis procedures, harsh reaction conditions, and unexpected environmental impact. Based on the principles of "Green Chemistry", considerable efforts have been done for breaking through the limitations, and significant progress has been made in the sustainable synthesis of Zr-MOFs over the past decade. In this review, the advancements of green raw materials and green synthesis methods in the synthesis of Zr-MOFs are reviewed, along with the corresponding drawbacks. The challenges and prospects are discussed and outlooked, expecting to provide guidance for the acceleration of the industrialization and commercialization of Zr-MOFs.

Single-Atom Fe Catalyst Outperforms Its Homogeneous Counterpart for Activating Peroxymonosulfate to Achieve Effective Degradation of Organic Contaminants.

Recently, reactive iron species (RFeS) have shown great potential for the selective degradation of emerging organic contaminants (EOCs). However, the rapid generation of RFeS for the selective and efficient degradation of EOCs over a wide pH range is still challenging. Herein, we constructed FeN4 structures on a carbon nanotube (CNT) to obtain single-atom catalysts (FeSA-N-CNT) to generate RFeS in the presence of peroxymonosulfate (PMS). The obtained FeSA-N-CNT/PMS system exhibited outstanding and selective reactivity for oxidizing EOCs over a wide pH range (3.0-9.0). Several lines of evidences suggested that RFeS existing as an FeN4═O intermediate was the predominant oxidant, while SO4·- and HO· were the secondary oxidants. Density functional theory calculation results revealed that a CNT played a key role in optimizing the distribution of bonding and antibonding states in the Fe 3d orbital, resulting in the outstanding ability of FeSA-N-CNT for PMS chemical adsorption and activation. Moreover, CNT could significantly enhance the reactivity of the FeN4═O intermediate by increasing the overlap of electrons of the Fe 3d orbital, O 2p orbital, and bisphenol A near the Fermi level. The results of this study can advance the understanding of RFeS generation in a heterogeneous system over a wide pH range and the application of RFeS in real practice.

Waste tire carbon in synergetic interaction with spent gamma radioactive source for efficient radiocatalytic degradation of organic dye.

Enhanced degradation of organic dye was achieved using two different kinds of waste materials: waste tire granules and spent sealed radioactive sources. Waste tire granules were used as raw material for the production of waste tire char (WTC), which was further utilized as an adsorbent matrix for synergetic adsorption/irradiation degradation of organic dye. The spent radioactive sources were radiographic sealed sources that originate from the industry which generate the high energy radiation. Methylene Blue (MB) was used as an organic model compound. Synthesized WTC has turbostratic structure, irregular shaped particles and developed mesoporous surface. Complete degradation of 0.02 dm3 of 100 mg dm-3 MB solution, having WTC dose of 1.25 g dm-3, was achieved with delivered doze of only 60 Gy. The applied doses were 100 times smaller than those presented in the literature. Degradation pathway was determined: OH radicals that originate from radiolysis of water and from the surface of WTC played the crucial role in the radiocatalytic degradation of MB. Breakage of the aromatic ring of MB appeared by the scission of the double C‒S+Ë­C bond as a result of the attack of OH species on adsorbed and electronically reorganized MB molecule.

Hierarchically porous metal-organic frameworks: synthesis strategies, structure(s), and emerging applications in decontamination.

Metal-organic frameworks (MOFs) with high porosity have received much attention as promising materials for many applications owing to their unique properties. However, to date, most of the reported MOFs have microporous structures, which slow down diffusion/mass transfer and limit the accessibility of bulky molecules to its internal surface. Thus, it is crucial to develop an efficient way to create larger pores (mesoporous and/or macroporous) into microporous MOFs to form hierarchical porous metal-organic frameworks (HP-MOFs), which facilitate the diffusion and mass transfer of guest molecules. HP-MOFs are excellent and promising candidates for environmental applications under the background of environmental contaminations. In this review paper, we are primarily focusing on the latest progress in the preparation of HP-MOFs by employing template-assisted and template-free synthetic approaches for environmental cleaning applications. Particularly, the adsorptive purification of the most common toxic substances, including gases, dyes, heavy metal ions, and antibiotics from the environment using HP-MOFs as adsorbents is briefly discussed. The overall results clearly showed that the superiority of HP-MOFs compared with conventional microporous MOFs. Finally, we summarize the remaining challenges and provide personal perspectives on possible future development of HP-MOFs.

Modeling the Spatial Distribution of Plateau Pika (Ochotona curzoniae) in the Qinghai Lake Basin, China.

The plateau pika (Ochotona curzoniae) is a keystone species in the alpine rangeland ecosystem of the Qinghai-Tibetan Plateau. Most previous studies of habitat selection by plateau pika have been conducted at a local microhabitat scale; however, little is known about the relationship between the distribution of plateau pika and macrohabitat factors at broad spatial scales. Using a presence-only ecological niche model (maximum entropy, Maxent), we predicted the distribution of plateau pika in the Qinghai Lake basin based on a set of environmental and anthropogenic variables at 1-km spatial resolution, and identified key macrohabitat factors that contribute to the predictive performance. Our results showed suitable area for plateau pika in the Qinghai Lake basin being approximately 3982 km2, which is 15.8% of the land area in the whole watershed. The distance to road emerged as the most important predictor of the distribution patterns of plateau pika, while the soil type was of ancillary importance. Mean air temperature of wettest quarter, distance to resident site and altitude also produced high gains in defining plateau pika's distribution. A higher predictive accuracy was achieved by the model that combined environmental and anthropogenic variables. With the constraint of human factors, the presence probability of plateau pika in about 1661 km2 will increase. These findings demonstrate the impact of human activities on the distribution of plateau pika, and the importance of vegetation reservation for plateau pika control.

Novel sensing platform based on gold nanoparticle-aptamer and Fe-metal-organic framework for multiple antibiotic detection and signal amplification.

The development of a feasible antibiotic detection method is important in water quality analysis. In this study, we developed a metal-organic framework (MOF)-aptamer-3,3',5,5'-tetramethylbenzidine (TMB)-H2O2-based sensing platform composed of the reaction variable of TMB catalytic oxidation as the label (from colorless to blue) and aptamer as the target recognition element for antibiotic detection. The platform works by calculating the relation between the antibiotic concentration and the resultant decrease in MOF's catalytic activity. Basing from the comparison of typical iron-based MOF materials (Fe-MIL-53, Fe-MIL-88A, and Fe-MIL-100), we selected Fe-MIL-53 to obtain an improved signal amplification effect. The outstanding performance of the Fe-MIL-53-based sensing platform can be attributed to its topological flexibility and small electron transfer impedance. In addition, a signal increment of up to 86% was obtained with an intensified gold nanoparticle (AuNP)-supported aptamer. The inhibitory catalytic activity stemmed from the coating of antibiotic-(AuNP-aptamer) conjugates onto the outer surface of the MOF material, which increased the impedance and decreased the electron transfer efficiency. Validation results indicated that the platform showed high selectivity and sensitivity (i.e., wide linearity range of 50-200 nM, detection limit up to 8.1 ng/mL, and recovery rate of 106%-110%) for chloramphenicol detection and universal applicability for other antibiotics, including ampicillin, tetracycline, and oxytetracycline. In general, the detection reliability and easy operation of this platform render it a promising candidate for antibiotic detection in future water quality monitoring practices.

Impact of inhalational anesthetics on postoperative cognitive function: Study protocol of a systematic review and meta-analysis.

BACKGROUND: Conflict findings of the impact of inhalational anesthetics on postoperative cognitive function are reported. No systematic review has been performed to solve the problem. The aim of the study was to assess the effect of different inhalational anesthetics on postoperative cognitive function in a network meta-analysis. METHODS: We will search MEDLINE, EMBASE, the Central Register of Controlled Trials in the Cochrane library, and CINAHL for randomized controlled trials or cohort studies assessing the short-term or long-term cognitive function of elderly patients (over 60 years) receiving major surgeries and inhalational anesthetics (desflurane, isoflurane, sevoflurane, halothane, and nitrous oxide) during surgery. Two reviewers will independently screen study eligibility, extract information from eligible studies, and appraise study quality. The impact of inhalational anesthetics will be assessed through: incidence of postoperative cognitive dysfunction at 1 week, 3 months, 1 year, and over 1 year after surgery; incidence of post-operative delirium; test of postoperative cognitive function. RESULTS: The results of this systematic review and meta-analysis will be published in a peer-reviewed journal. CONCLUSION: To our knowledge, this systematic review will be the first to evaluate existing research on the incidence of postoperative cognitive function after inhalational anesthetics. Our study will assess the effect of different inhalational anesthetics on postoperative cognitive function. ETHICS AND DISSEMINATION: The review will be finished in December 2017, and the result will be published in a peer-reviewed journal or disseminated through conference posters or abstracts. REVIEW REGISTRATION NUMBER: CRD42017056675 (www.crd.york.ac.uk/PROSPERO).

Green synthesis and evaluation of an iron-based metal-organic framework MIL-88B for efficient decontamination of arsenate from water.

Iron-containing metal-organic frameworks (MOFs) have gradually emerged as environmentally benign alternatives for reducing the levels of environmental contamination because of their advantages, such as readily obtained raw materials with low cost, nontoxic metal source with good biocompatibility, and distinguished physicochemical features e.g., high porosity, framework flexibility, and semiconductor properties. In this study, we reported an innovative strategy for synthesizing an iron-based MOF, MIL-88B, at room temperature. The novelty of this strategy was the use of ethanol as solvent and the pretreatment of dry milling with neither the bulk use of a toxic organic solvent nor the addition of extremely dangerous hydrofluoric acid or strong alkali. The synthesized MIL-88B(Fe) was evaluated as a sorbent for removing arsenate in water and it exhibited high adsorption capacity (156.7 mg g-1) at a low dosage. The removal capacity of trace arsenate on MIL-88B(Fe) was 32.3 mg g-1 at a low equilibrium concentration (6.4 µg L-1), which satisfied the arsenic threshold for drinking water. The results of Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the As(v) molecules bonded with the oxygen molecules, which were coordinated with FeO clusters in the framework. This work presented the potential use of the up-scaled MIL-88B as an excellent sorbent for purifying arsenate-contaminated water.

Controllable Modular Growth of Hierarchical MOF-on-MOF Architectures.

Fabrication of hybrid MOF-on-MOF heteroarchitectures can create novel and multifunctional platforms to achieve desired properties. However, only MOFs with similar crystallographic parameters can be hybridized by the classical epitaxial growth method (EGM), which largely suppressed its applications. A general strategy, called internal extended growth method (IEGM), is demonstrated for the feasible assembly of MOFs with distinct crystallographic parameters in an MOF matrix. Various MOFs with diverse functions could be introduced in a modular MOF matrix to form 3D core-satellite pluralistic hybrid system. The number of different MOF crystals interspersed could be varied on demand. More importantly, the different MOF crystals distributed in individual domains could be used to further incorporate functional units or enhance target functions.

Maltose Utilization as a Novel Selection Strategy for Continuous Evolution of Microbes with Enhanced Metabolite Production.

We have developed a novel selection circuit based on carbon source utilization that establishes and sustains growth-production coupling over several generations in a medium with maltose as the sole carbon source. In contrast to traditional antibiotic resistance-based circuits, we first proved that coupling of cell fitness to metabolite production by our circuit was more robust with a much lower escape risk even after many rounds of selection. We then applied the selection circuit to the optimization of L-tryptophan (l-Trp) production. We demonstrated that it enriched for specific mutants with increased l-Trp productivity regardless of whether it was applied to a small and defined mutational library or a relatively large and undefined one. From the latter, we identified four novel mutations with enhanced l-Trp output. Finally, we used it to select for several high l-Trp producers with randomly generated genome-wide mutations and obtained strains with up to 65% increased l-Trp production. This selection circuit provides new perspectives for the optimization of microbial cell factories for diverse metabolite production and the discovery of novel genotype-phenotype associations at the single-gene and whole-genome levels.