Three-dimensional Structure Research Articles

Cellulose/sodium alginate gel electrolyte membranes with synergistic hydrogen bonding and metal ion coordination networks for high performance aqueous zinc-ion batteries

Cellulose has outstanding potential for application in energy storage batteries due to its high temperature resistance, high electrolyte affinity, renewability, and suppression of the shuttle effect, but single cellulose membranes still suffer from problems such as inhomogeneous pore distribution and unstable three-dimensional network structure. In this study, a green and sustainable regenerative cellulose (RC)/sodium alginate (SA) gel electrolyte membrane is developed by sol-gel process, the double crosslinked network scaffold centered on Zn2+ was constructed by the synergistic hydrogen-bonding and metal ion- coordination network, the stable and uniform pore structure was also formed. The obtained RC-SA gel electrolyte membrane exhibits outstanding performance, featuring a dual crosslinked network with abundant pore structure and numerous polar groups that effectively enhance Zn2+ transport, significantly improving battery cycling performance. The corresponding RC-SA gel electrolyte membrane demonstrates high ionic conductivity (6.30 mS·cm−1) and Zn2+ transference number (0.66), leading to excellent reversible capacity (159 mA·h·g−1) and self-discharge suppression capability (maintaining 99.2 % of capacity after a 24 h standstill) in Zn//V2O5 full-cell. The coulombic efficiency and cycling stability of the Zn//Cu half-cell and Zn//Zn symmetric cell using RC-SA gel electrolyte membrane outperforms that of the glass fiber separator, highlighting its multifunctionality and potential applications.

Preparation of energy-efficient, environmentally friendly and high-strength biocomposites from wood fibre ultramicro self-composite cellulose matrices

Considering the diminishing forest as a natural resource, the efficient use of small-diameter shrubs is crucial for global sustainable development. This approach has significant potential to prevent wasting forest resources and reduce carbon emissions. However, small-diameter timber has inherent drawbacks, such as the looseness of this material, susceptibility to cracking and deformation, and low strength, all of which significantly impact its range of applications. In this study, an efficient, green method was developed to prepare adhesive-free biocomposites from discarded small-diameter shrubs via ultrasonic pretreatment and thermoforming. After the ultrasonic pretreatment, the flexural and tensile strengths of the biocomposites increased by 145% and 132%, respectively. Ultrasonic pretreatment separated and destroyed chemical bonds among the lignocellulosic biomass macromolecules through high-speed shear and microjets. This process significantly increased the amount of binding sites on the cellulose fibres, and further densified the cell walls through hot pressing. Moreover, the ultrasonic pretreatment may remove components of the wood flour that act as fillers or density enhancers, resulting in a reduction in the density of the biocomposite. Simultaneously, lignin acted as a binder and improved fibre bonding through both physical and chemical cross-linking, resulting in a dense cellulose structure with a three-dimensional lattice structure and a less hydrophilic surface, as evidenced by a water contact angle of 81.72°. In addition, the high-quality, binder-free biocomposites did not emit harmful gases such as formaldehyde. Hence, they are expected to become sustainable materials for building decoration and furniture applications in the future.

Cellular diversity of human inner ear organoids revealed by single-cell transcriptomics.

Human inner ear organoids are three-dimensional tissular structures grown in vitro that recapitulate some aspects of the fetal inner ear and allow the differentiation of inner ear cell types. These organoids offer a system in which to study human inner ear development, mutations causing hearing loss and vertigo, and new therapeutic drugs. However, the extent to which such organoids mimic in vivo human inner ear development and cellular composition remains unclear. Several recent studies have performed single-cell transcriptomics on human inner ear organoids to interrogate cellular heterogeneity, reveal the developmental trajectories of sensory lineages and compare organoid-derived vesicles to the developing human inner ear. Here, we discuss the new insights provided by these analyses that help to define new paths of investigation to understand inner ear development.

Prediction of YY1 loop anchor based on multi-omics features

The three-dimensional structure of chromatin is crucial for the regulation of gene expression. YY1 promotes enhancer-promoter interactions in a manner analogous to CTCF-mediated chromatin interactions. However, little is known about which YY1 binding sites can form loop anchors. In this study, the LightGBM model was used to predict YY1-loop anchors by integrating multi-omics data. Due to the large imbalance in the number of positive and negative samples, we use AUPRC to reflect the quality of the classifier. The results show that the LightGBM model exhibits strong predictive performance (AUPRC≥0.93). To verify the robustness of the model, the dataset was divided into training and testing sets at a 4:1 ratio. The results show that the model performs well for YY1-loop anchor prediction on both the training and independent testing sets. Additionally, we ranked the importance of the features and found that the formation of YY1-loop anchors is primarily influenced by the co-binding of transcription factors CTCF, SMC3, and RAD21, as well as histone modifications and sequence context.

Equatorial plasma bubble model and integrity risk evaluation for ground based augmentation system in Hong Kong

The spatial gradient induced by the Equatorial Plasma Bubble (EPB) in low latitude regions is a major challenge for the Ground Based Augmentation System (GBAS). To facilitate the implementation and operation of GBAS Approach Service Type (GAST)-D at Hong Kong International Airport, the impact of EPB induced spatial gradients needs to be analyzed. Previous simulations using a two-dimensional trapezoid model neglected the three-dimensional structure of the EPB, assuming ionospheric delay on a thin shell at a specific altitude. To address this limitation, this paper adopts a cube above the magnetic equator to characterize the EPB threat model. The ionospheric delay difference between satellite signals passing through the EPB model is limited by the upper bound spatial gradient derived with the data collected from Hong Kong Satellite Positioning Reference Station Network. The simulation results reveal that ionospheric monitors in GAST D can satisfy the Category II/III approach requirement, i.e., the probability of missed detection PMD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${P}_{\ ext{MD}}$$\\end{document} for the differential range error Er larger than 2.75 m is lower than 1×10-9\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${1\ imes 10}^{-9}$$\\end{document}. The potentially hazardous event with the largest Er of 2.47 m and PMD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${P}_{\ ext{MD}}$$\\end{document} of 1.86×10-9\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${1.86\ imes 10}^{-9}$$\\end{document} occurs when the satellite signal moves parallel to the equator near the Equatorial Ionization Anomaly (EIA) region, and its significant portion traverses in the EPB depletion region.

The effects of orientation angle of bamboo strands on the properties of bamboo oriented strand board

Bamboo oriented strand boards (BOSBs) with orientation angles of bamboo strand ranging from 0° to 90°, with increments of 15° were fabricated in this study at first. The effect of orientation angles on the physical and mechanical properties of the boards in the terms of the thickness swelling (TS), static bending performance, and internal bond (IB) were then comprehesively evaluated. Simultaneously, the cross-sectional morphology, porosity, and internal three-dimensional structure of the boards were investigated further via a super depth-of-field digital microscope, mercury intrusion porosimetry (MIP), and Micro-Computed Tomography (Micro-CT), to elucidate the underlying influence mechanisms of strand orientation angle on board performance. Results demonstrated that the orientation angle of bamboo strands significantly impacts the performance of BOSBs. When the orientation angle of bamboo strands ranged from 0° to 45°, the structure of the BOSB was relatively loose, with porosity increasing as the orientation angle increased. The highest porosity was observed at a 45° orientation angle. However, when the orientation angle exceeded 45°, the inter-layer and intra-layer bamboo strands gradually formed an effective interlocking structure, leading to a decrease in porosity with increasing orientation angle. This interlocking phenomenon was a crucial factor contributing to the improved mechanical properties of the board. The optimal orientation angle range was found to be between 60° and 75°, where the overall board performance met the requirements for heavy-duty BOSBs under humid conditions.

Identification of Cell Wall Binding Domains and Repeats in Streptococcus pneumoniae Phage Endolysins: A Molecular and Diversity Analysis

Streptococcus pneumoniae (pneumococcus) is a multidrug-resistant pathogen associated with pneumonia, otitis media, meningitis and other severe complications that are currently a global threat to human health. The World Health Organization listed Pneumococcus as the fourth of twelve globally prioritized pathogens. Identifying alternatives to antibiotic therapies is urgently needed to combat Pneumococcus. Bacteriophage-derived endolysins can be used as alternative therapeutics due to their bacterial cell wall hydrolyzing capability. In this study, S. pneumoniae phage genomes were screened to create a database of endolysins for molecular modelling and diversity analysis of these lytic proteins. A total of 89 lytic proteins were curated from 81 phage genomes and categorized into eight groups corresponding to their different enzymatically active (EAD) domains and cell wall binding (CBDs) domains. We then constructed three-dimensional structures that provided insights into these endolysins. Group I, II, III, V, and VI endolysins showed conserved catalytic and ion-binding residues similar to existing endolysins available in the Protein Data Bank. While performing structural and sequence analysis with template lysin, an additional cell wall binding repeat was observed in Group II lysin, which was not previously known. Molecular docking performed with choline confirmed the existence of this additional repeat. Group III endolysins showed 99.16% similarity to LysME-EF1, a lysin derived from Enterococcus faecalis. Furthermore, the comparative computational analysis revealed the existence of CBDs in Group III lysin. This study provides the first insight into the molecular and diversity analysis of S. pneumoniae phage endolysins that could be valuable for developing novel lysin-based therapeutics.

Enhanced strength and ductility of boron nitride nanosheet reinforced cu composites through constructing an interfacial three-dimensional structure

To address the poor wettability and weak interface bonding between boron nitride nanosheet (BNNS) and Cu, BNNS/CuTi composites were prepared through matrix microalloying by adding 1 wt% Ti. Solid-state interfacial reactions resulted in the formation of TiN transition layers and TiB whiskers (TiBw), collectively constructed a BNNS-(TiN&TiB)-Cu interfacial three-dimensional structure (I-3DS). The coherent I-3DS significantly reduced the interfacial energy, improved the interfacial stability, and achieved a favorable combination of strength and ductility in BNNS/CuTi composites. The 0.1 wt% BNNS/CuTi composite achieved an ultimate tensile strength (UTS) of 485 MPa, representing increases of 114 % and 62 % over pure Cu and 0.1 wt% BNNS/Cu composite, respectively. The interlocking structure formed by I-3DS and Cu doubled the theoretical interface shear strength limit and improved load transfer efficiency. This study offered new insights into the innovative design of high-performance Cu matrix composites (CMCs) by constructing I-3DS.

Functional Nanocomposites: From Strategic Design to Applications

Nanomaterials with one-, two-, or three-dimensional structures have exhibited superior optical, electronic, magnetic, thermal, and mechanical properties compared to their bulk material counterparts [...]

Polyethylene glycol modified polysiloxane and silver decorated expanded graphite composites with high thermal conductivity, EMI shielding, and leakage-free performance

Phase change thermal interface materials (PCTIMs) have attracted significant attention due to their dual capability in temperature control and thermal buffering. However, the widespread application of PCTIMs in electronic devices is hindered by critical drawbacks such as low thermal conductivity (к), absence of electromagnetic interference shielding effectiveness (EMI SE), poor flexibility, and susceptibility to leakage. In this study, leakage-free PCTIMs were successfully fabricated with ultra-high thermal conductivity (к∥ = 23.4 W m−1 K−1, к⊥ = 8.1 W m−1 K−1), outstanding phase change functionality, exceptional EMI SE (73.2 dB), and excellent flexibility. A polyethylene glycol-modified polydimethylsiloxane (pPDMS) was synthesized through chemical grafting, demonstrating its significant potential as substrates for PCTIMs. Moreover, a designed material called silver nanoparticles-decorated expanded graphite (Ag-EG), was prepared to facilitate multidimensional material collaboration and incorporated into the pPDMS matrix to obtain Ag-EG@pPDMS composites. This integration resulted in a three-dimensional (3D) multi-layer orientation structure that enabled superior thermal conductivity in both in-plane and through-plane directions. To investigate the influence of 3D multi-layer orientation structure on Ag-EG@pPDMS, theoretical analysis was conducted using Effective Medium Theory (EMT) and Foygel thermal conduction models, which were further simulated by finite element analysis confirming substantial enhancement in material properties attributed to the 3D multi-layer orientation structure. Thermal management and electromagnetic interference (EMI) shielding applications were conducted using computers, wireless bluetooth earphones, and other electronic devices, indicating the superior thermal conductivity and EMI shielding of Ag-EG@pPDMS composites.

Assessing data variability in groundwater quality monitoring of contaminated sites through factor analysis and multiple linear regression models

Monitoring of long-term contaminant concentrations trends is essential to verify that attenuation processes are effectively occurring at a site. However, monitoring data are often affected by extreme variability which prevents the identification of clear concentration trends. The variability is higher in long-screened monitoring wells, which are currently used at many contaminated sites, although it has been known since the 1980s that monitoring data from long-screened wells can be biased. Understanding the factors that may influence the variability of monitoring data is pivotal. To this end, following hydrochemical conceptual modelling using a multi-method approach, the variability of hydrocarbon concentrations from fully screened monitoring wells was assessed over eleven years at a former oil refinery located in Northern Italy. The proposed methodology combined factor analysis with multiple linear regression models.Results pointed out a higher variability in hydrocarbon concentrations at the plume fringe and a lower variability at the plume source and core. 44–46 % of the total variability in measured hydrocarbon concentrations is due to “intrinsic plume heterogeneity”, related to the three-dimensional structure of a contaminant plume, which becomes thinner at the edge, creating a vertical heterogeneity of redox conditions at the plume fringe. This variability, expressed as increasing concentrations of sulfate and decreasing concentrations of methane, represents a background variability that cannot be reduced by improving sampling procedures. The remaining 56–54 % of the total variability may be due to the non-standardization of some purging and sampling operations, such as pump intake position, purging and sampling time/flow rates and variations in the analytical methods. This finding suggests that monitoring improvements in fully screened wells by standardizing all purging/sampling operations or using sampling techniques that can reduce the actual screen length (e.g., packers or separation/dual pumping techniques) would reduce data variability by more than half.

Micro-Nanofiber Three-Dimensional Antibacterial Sponge with Wetting/Pore Dual Gradient for Rapid Liquid Infiltration and Uniform Retention in Diapers.

The core layer of disposable diapers typically contains a blend of superabsorbent polymer (SAP) and pulp, resulting in slow liquid absorption, layer separation, reverse osmosis, and potential skin issues owing to the addition of antibacterial agents to the surface layer. Therefore, a core layer with rapid liquid absorption, uniform retention, and antibacterial properties must be developed to improve wearer comfort. In this study, a three-dimensional network porous structure for the core layer of a disposable diaper was prepared by solution blow spinning (SBS). This structure comprised a superabsorbent fiber (SAF) and hydrolyzed polyacrylonitrile (HPAN) micro/nanofibers with a dual gradient in wetting/pore size. Progressively increasing the SAF content in each layer to incrementally increase wettability and controlling fiber diameter, a gradient pore structure with sizes of approximately 30 μm-16 μm-7 μm was formed. This design exhibited rapid infiltration capability, reducing the third liquid infiltration time by 13 s compared to those of commercial core layers while reducing reverse osmosis by 1.4 g, and the liquid absorption and retention rates are 47.7 times and 46.1 times, respectively, which is 1.6 times higher than those of commercial diapers. In addition, incorporating a natural antibacterial agent, ε-poly-l-lysine hydrochloride (ε-PLH), into the core layer resulted in an antibacterial rate exceeding 99.99% without direct contact with the skin; water transport capacity tests confirmed faster liquid infiltration speed, uniform absorption, and no fault formation.

Scalable production of flexible and multifunctional graphene-based polymer composite film for high-performance electromagnetic interference shielding

Graphene have gained significant interest for potential in lightweight, ultrathin, and flexible electromagnetic interference (EMI) shielding materials due to their high electrical conductivity, low density, and ability to dissipate electromagnetic waves, but its poor dispersibility and processability hinders its applications. Besides, there is an urgent need for EMI shielding materials with multifunctional features. Herein, we proposed a flexible graphene/carbon nanotubes/polyurethane (GC/PU) composite film with a dense three-dimensional multilayer structure. This resultant GC/PU film shows high tensile strength of 42.9 MPa, ultra-high conductivity of 2087.2 S/m, and X-band EMI shielding efficiency of 37.7 dB at a thickness of 130 μm and even higher value of 72.1 dB at 520 μm. Moreover, this GC/PU film demonstrates an excellent electric heating performance (surface temperature of 127.5 °C at 5.0 V, thermal response <20 s) and flame-retardant capability, which endows it with the capability of anti-icing/de-icing. Therefore, this work may provide a promising approach for developing high-performance EMI shielding composites that may be used in the areas of wearables, defense, and aerospace.

Exploration of urease-aided calcium carbonate mineralization by enzyme analyses of Neobacillus mesonae strain NS-6.

Urease containing nickel cofactor is crucial for urea-hydrolytic induced calcium carbonate (CaCO3) precipitation (UICP). However, limited information exists regarding the influence of amino acid residues interacting with nickel ions in its structure on induced CaCO3 mineralization. Herein, RT-qPCR was used to demonstrate that the addition of NiCl2 dramatically upregulated the expression of urease structural gene ureC that was correlated with nickel binding in Neobacillus mesonae strain NS-6. Homology modeling and molecular docking were employed to construct the three-dimensional structure of urease and seek the key residues involved in nickel binding process, and virtual mutation technology was adopted to inform three key residues coordinated with nickel ions and urea, His249, His275, and Asp363. Four metrics, including root mean square deviation values for mutations of those key residues in urease-urea complexes severally and wild-type, were calculated by molecular dynamics simulations when they were mutated into alanine, respectively. Subsequently, the mutations of H249A, H275A, and D363A were characterized using western blotting to reveal a decrease in the relative expression and activity of urease, along with a corresponding reduction in CaCO3 precipitation. Ultimately, the mutations also exhibited that they had lower substrate affinity and catalytic efficiency for urea through enzymatic properties analysis. The findings suggested that those residues played a pivotal role in UICP of strain NS-6, which would expand the theoretical basis for modulating urease activity.IMPORTANCEUrease-producing bacterium is of great importance in diverse application fields, such as environmental remediation, due to its key driving characteristics in catalyzing urea hydrolysis via urea-hydrolytic induced CaCO3 precipitation (UICP). As essential cofactors of urease, nickel ions play a crucial role in regulating urease catalysis and maintaining structural stability. Numerous investigations have emphasized the impact of nickel ions on urease activity in recent years, to our best knowledge, only a few literatures have studied the molecular-level regulation of nickel-ligand residues. This study focused on the highly urease-producing bacterial Neobacillus mesonae NS-6 to explore the effects of specific nickel-ligand residues on the urease-aided CaCO3 mineralization process using molecular simulation predictions and targeted mutation experiments. The aim was to provide a molecular-level understanding of the interactive effects between urea and critical residues associated with the urease active center, as well as propose an effective modification strategy to enhance the application of UICP in future environmental areas.

An efficient topology optimization algorithm for large-scale three-dimensional structures

An efficient topology optimization algorithm for large-scale three-dimensional structures

Multilevel immobilized CNT/SCN purification beads and the removal efficiency over TC[sbnd]HCl/clay composite pollutant in the underwater environment

Natural water bodies often contain a significant amount of suspended colloidal particles, which not only reduce water transparency but also have a high adsorption capacity for soluble pollutants. These composite pollutants can migrate rapidly with water flow, which are usually difficult to degrade and remove by traditional methods. Aiming at suspended contaminated waterbodies, this study introduced a multilevel loading method to prepare carbon nanotube/sulfur doped carbon nitride (CNT/SCN) composite photocatalytic purification beads. The surface of the obtained core-shell structured purification beads is loaded with CNT/SCN photocatalysts which exhibit three-dimensional conductive and porous characteristics. TCHCl was introduced as the target pollutant, and the removal efficiency of the composite purification beads under different water turbidity and hydrodynamic conditions were investigated. The results showed that during 15 h of degradation process, at the depth of 20 cm, with the flow rate of 0.015 m3/h and water turbidity of 10.3 NTU, the purification beads achieved a removal efficiency of 54.9% for tetracycline hydrochloride (TCHCl), which was 2.03 times higher than that of SCN purification beads. The three-dimensional porous structure of the surface exhibited excellent adsorption and trapping capabilities for suspended colloidal particles. The introduction of carbon nanotubes enhanced charge transfer ability of the surface layer and reduces the local charge accumulation effect caused by surface adsorption, which effectively enhances the adsorption of suspended colloid, and also significantly improved the degradation efficiency of TCHCl. This study provides a valuable insight for the engineering application of photocatalytic technology.

Experimental study on crack repair materials for masonry ancient building based on skeleton effect

In order to obtain “repair the old as the old” ancient building crack repair materials and cracks on both sides of the wall does not produce internal stress and secondary damage, this study uses acrylamide as the core gelling material, brick powder as the force transmitting skeleton of the hydrogel material modification, the preparation of the brick powder hydrogel. The dry density, modulus of elasticity, compressive strength, toughness and dissolution properties of hydrogels with different grey brick powder admixtures were tested. Scanning electron microscopy (SEM) was used to reveal the binding mechanism in the microstructure of acrylamide hydrogel modified with brick powder. The results show that the grey brick powder particles can be embedded in the three-dimensional network structure of the hydrogel in a more complete way, which effectively improves the mechanical properties and swelling properties of the hydrogel itself; With the increase in the proportion of brick powder, the dry density, compressive strength, toughness of the brick powder hydrogel were significantly increased, and the equilibrium swelling was significantly reduced, when the proportion of 70 % of compressive strength increased by 2998.06 %, toughness increased by 2250.03 %, and the equilibrium swelling was reduced by 716.12 %. Brick powder hydrogel performance and color meet the requirements of crack repair in masonry ancient building.

Stepwise Construction of Supramolecular A2B4-Type Miktoarm Star Copolymers with a Cobalt Phthalocyanine Core.

Supramolecular interactions between polymers play a crucial role in the construction of three-dimensional polymer structures with unique physical and chemical properties. In this study, we have fabricated a novel supramolecular miktoarm star copolymer (μ-star) with a cobalt(II) phthalocyanine (CoPc) core using metal-ligand coordination. Axial coordination of the terminal pyridyl group of poly(methyl methacrylate) with the CoPc core of four-armed star-shaped polystyrene provided AB4- and A2B4-type μ-stars through stepwise complexation. The spin-coated polymer films from mixed solutions of CoPcPS4 and pyPMMA in 1 : 1 or 1 : 2 mass ratios exhibited phase-separated nanodomains with smooth surfaces. Supramolecular interactions in polymer systems provide a unique topology to polymers and affect their bulk morphology.

Spherical Nucleic Acid Probes on Floating-Gate Field-Effect Transistor Biosensors for Attomolar-Level Analyte Detection.

Field-effect transistor (FET) sensors are attractive for the label-free detection of target biomolecules, offering ultrahigh sensitivity and a rapid response. However, conventional methods for modifying biomolecular probes on sensors often involve intricate and time-consuming procedures that require specialized training. Herein, we propose a simple and versatile approach to functionalize floating-gate (FG) FET sensors by exploiting the strong binding ability of polyvalent interactions and the three-dimensional structure of densely functionalized spherical nucleic acids (SNAs). Crucially, the SNAs can be easily deposited onto a dielectric layer under mild conditions, ensuring stable immobilization of the probes. Further, the SNAs show efficient and robust immobilization on various dielectric layers including Y2O3, Ta2O5, and HfO2, forming conjugates that resist denaturation by various agents. By modifying the DNA sequence within the SNAs, we achieved highly sensitive FG-FET biosensors for DNA, adenosine triphosphate, and viral nucleic acids at the attomolar level. For clinical samples detection, unamplified enterovirus 71 RNA at levels as low as 0.13 copies μL-1 was detected within 100 s. Moreover, the sensor attained 100% accuracy for analyte detection in both positive and negative samples. Our findings provide a general and simple method for fabricating FET-based biochemical sensors and demonstrate that the SNA-modified FG-FET biosensor is a versatile and reliable integrated platform for ultrasensitive biomarker detection.

Molecular characterization of extended-spectrum β-lactamases from the Akkermansia genus

Akkermansia muciniphila, a member of the Verrucomicrobiota phylum, is recognized as a key gut microbe and has emerged as a potential next-generation probiotic. Assessment of antibiotic resistance in probiotics is a prerequisite for their application, while very few is studied in Akkermansia species. To address this, eight representative class A β-lactamases (36.90 %–41.30 % identity with known β-lactamases) from the Akkermansia species were screened and found to increase the minimum inhibitory concentration (MIC) of Escherichia coli to β-lactams (2–1024 fold). Secondly, four β-lactamases were successfully purified and identified as extended-spectrum β-lactamase because they exhibited hydrolase activity against β-lactams from penicillin, cephalosporins, and monobactam classes. Based on predicted three-dimensional structure, we hypothesized and validated that serine at 51 position was catalytic amino acid. Thirdly, the genomic context analysis revealed the absence of mobile genetic elements or other antibiotic resistance genes surrounding β-lactamase genes, suggesting they may not be transferable. This study provides a foundational basis for the safety evaluation of Akkermansia species as probiotics.