Separate Platforms Research Articles

Fluid–structure boundary-driven simultaneous standard-inverse Chladni patterns for selective particles manipulation

In fluid, particles patterning and selective manipulation are essential for material, biomedical, and robotic handling. The German physicist Chladni has investigated the particles manipulation on a flat vibrating plate. Generally, particles bounce with the vibrating plate, gradually accumulate to nodal lines or anti-nodes, forming either standard or inverse Chladni patterns. The Chladni patterns show great potential for particles assembly in different environments. The mechanisms for simultaneous manipulation by multiple kinds of forces are still unclear. Here, the Chladni plate with a vertical boundary is used for selective particles manipulation. The simultaneous standard-inverse Chladni patterns are realized on the vibrating plate by modulating the frequency. First, the particles patterning mechanisms on the Chladni plate with vertical boundary are investigated for the acoustic radiation force and the acoustic streaming. The simultaneous standard-inverse Chladni patterns are realized due to the driving of vertical boundary. Then, through switching the excitation frequencies, the tunable particles patterns are realized. Finally, the selective separation of particles with different sizes and densities is investigated using the standard-inverse Chladni patterns. This work investigates the particles manipulation mechanisms on vibrating plate by the fluid–structure boundary-driven acoustic field, thereby potentially providing a platform for selective patterning and separation of particles.

P1330 The gut microbiome at the onset of inflammatory bowel disease: A systematic review of the literature and unified bioinformatic synthesis of sequencing data from >1000 treatment naïve patients

Abstract Background There are few studies of the gut microbiome in new-onset IBD. We present a novel secondary bioinformatic re-analysis (BA) of sequence outputs mapped to latest microbial taxonomy derived from systematic review. Methods MEDLINE and Embase searches were performed for microbiome studies in pre-treatment IBD. Appraisal was completed with ROBINS-E. Available 16S rRNA sequence datasets were downloaded and missing datasets requested. Integrated datasets were run through a unified pipeline based in QIIME2 supplemented by phyloseq and DESeq2. Results From 12,264 studies, 10,804 abstracts and 217 full texts were screened. 31 studies were eligible; 18 met the requirements for BA. Most were low risk for bias, except uncontrolled confounding. Methodology varied extensively. Considering only amplicon data; samples originated from 1,743 unique individuals (including 678 Crohn’s disease (CD), 399 ulcerative colitis (UC), 123 ‘other’ IBD, 130 healthy, 405 symptomatic, and 8 familial controls) derived from 15 countries. DNA was extracted using 15 different kits, sequencing performed on 4 separate platforms targeting 10 different 16S rRNA hypervariable regions. There was a paucity of adult data, particularly mucosal biopsies. Bacterial alpha diversity was reduced: in faeces in paediatric UC vs symptomatic controls (SC), in adult CD and UC vs HC and in paediatric SC vs HC (Figure 1). In paediatric biopsies in CD vs SC, CD vs UC, SC vs UC (Figure 2). Beta-diversity BA by Bray-Curtis demonstrated clear distinctions between faecal and mucosal biopsy communities, least evident in UC. Faecal communities separated by geography, though less evidently in biopsies. Differential abundance analysis revealed enrichment of oral genera across sample types (Fusobacterium, Peptostreptococcus, Neisseria in CD; Haemophilus, Aggregatibacter, Peptostreptococcus, Porphyromonas, Neisseria, Gemella in UC). Short-chain fatty acid (SCFA) producers were diminished but less consistently across IBD phenotype and sample type. Conclusion This work demonstrates the utility of a combined systematic review/secondary data analysis approach to published microbiome datasets. Whilst synthesis remains challenging due to the methodological inconsistencies within these studies, this approach better accounts for these variations and presents a new way to consider this data. A reduction in bacterial diversity remains core to the IBD microbiome, though with more complexity than previously considered (SC<UC in paediatric biopsies). Microbial community structure changes by sample type and geography. Enrichment of oral bacteria is consistent across IBD subtypes and sample types suggesting their importance in the disease. A deficit in SCFA producers may also be important.

A Gate-Opening Control Strategy via Nitrate-Chloride Anion Exchange for Enhanced Hydrogen Isotope Separation in Metal-Organic Frameworks.

Efficient separation of hydrogen isotopes, especially deuterium (D2), is pivotal for advancing industries such as nuclear fusion, semiconductor processing, and metabolic imaging. Current technologies, including cryogenic distillation and Girdler sulfide processes, suffer from significant limitations in selectivity and cost-effectiveness. Herein, we introduce a novel approach utilizing an imidazolium-based Metal-Organic Framework (MOF), JCM-1, designed to enhance D2/H2 separation through temperature-dependent gate-opening controlled by ion exchange. By substituting NO3⁻ ions in JCM-1(NO3⁻) with Cl⁻ ions to form JCM-1(Cl⁻), we precisely modulate the gate-opening threshold, achieving a significant enhancement in isotope selectivity. JCM-1(NO3⁻) exhibited a D2/H2 selectivity (SD2/H2) of 14.4 at 30 K and 1 bar, while JCM-1(Cl⁻) achieved an exceptional selectivity of 27.7 at 50 K and 1 mbar. This heightened performance is attributed to the reduced pore aperture and higher gate-opening temperature resulting from the Cl⁻ exchange, which optimizes the selective adsorption of D2. Our findings reveal that JCM-1 frameworks, with their tunable gate-opening properties, offer a highly efficient and adaptable platform for hydrogen isotope separation. This work not only advances the understanding of ion-exchanged MOFs but also opens new pathways for targeted applications in isotope separation and other gas separation processes.

Light-/pH-Regulated Spiropyran Smart-Responsive Hydrophilic Separation Platform for the Identification of Serum Glycopeptides from Hepatocellular Carcinoma Patients.

Smart-responsive materials have attracted much attention in the enrichment of post-translational modifications of proteins. In this work, for the first time, we developed a smart enrichment strategy (MNPs-l-DOPA/PEI-SP) based on the change in hydrophilic properties of spiropyran under the regulation of light and pH to realize the controllable enrichment and release of intact glycopeptides. The enrichment mechanism and possible binding mechanism were verified by theoretical calculations. The smart enrichment platform based on MNPs-l-DOPA/PEI-SP was used to screen glycoprotein biomarkers for hepatocellular carcinoma (HCC) to evaluate its cancer diagnostic and monitoring performance. A total of 3,864 intact N-glycopeptides containing 166 N-glycoproteins were successfully identified in serum samples of early-stage HCC patients, while 3,266 intact N-glycopeptides containing 193 glycoproteins were identified in normal control (NC) serum samples. This work not only provides new ideas for the efficient enrichment of intact glycopeptides with smart-responsive material, but also broadens the research possibilities for biomarker discovery in HCC serum liquid biopsies.

A Software Tool for Rapid and Automated Preprocessing of Large-Scale Serum Metabolomic Data by Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry.

Mass spectrometry (MS)-based metabolomics often rely on separation techniques when analyzing complex biological specimens to improve method resolution, metabolome coverage, quantitative performance, and/or unknown identification. However, low sample throughput and complicated data preprocessing procedures remain major barriers to affordable metabolomic studies that are scalable to large populations. Herein, we introduce PeakMeister as a new software tool in the R statistical environment to enable standardized processing of serum metabolomic data acquired by multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS), a high-throughput separation platform (<4 min/sample) which takes advantage of a serial injection format of 13 samples within a single analytical run. We performed a rigorous validation of PeakMeister by analyzing 47 cationic metabolites consistently measured in 5,000 serum and 420 quality control samples from the Brazilian National Survey on Child Nutrition (ENANI-2019) comprising a total of 224,983 metabolite peaks acquired in 40 days across three batches over an eight-month period. A migration time index using a panel of 11 internal standards was introduced to correct for large variations in migration times, which allowed for reliable peak annotation, peak integration, and sample position assignment for serum metabolites having two flanking internal standards or a single comigrating stable-isotope internal standard. PeakMeister accelerated data preprocessing times by 30-fold compared to manual processing of MSI-CE-MS data by an experienced analyst using vendor software, while also achieving excellent peak annotation fidelity (median accuracy >99.9%), acceptable intermediate precision (median CV = 16.0%), consistent metabolite peak integration (mean bias = -2.1%), and good mutual agreement when quantifying 16 plasma metabolites from NIST SRM-1950 (mean bias = -1.3%). Reference ranges are also reported for 40 serum metabolites in a national nutritional survey of Brazilian children under 5 years of age from the ENANI-2019 study. MSI-CE-MS in conjunction with PeakMeister allows for rapid and automated processing of large-scale metabolomic studies that tolerate nonlinear migration time shifts without complicated dynamic time warping or effective mobility scale transformations.

Enantioselective Membranes for Pharmaceutical Applications: A Comprehensive Review.

In the past decade, significant advances have been made in the field of chiral separation, which is crucial for biological and pharmaceutical applications. Enantioselective membranes have emerged as a promising platform for efficient chiral separation due to their unique properties such as large surface area, tunable pore size, and high selectivity. These membranes are particularly effective in separating enantiomers because of their ability to facilitate selective interactions between the membrane material and chiral molecules. This article provides a comprehensive review of the recent progress in enantioselective membranes for chiral separation. Key topics discussed include various membrane fabrication methods, functionalization approaches, and the characterization of membrane properties, specifically in the context of applications like drug delivery, biomolecule separation, and pharmaceutical analysis. Furthermore, the review addresses the current challenges, potential solutions, and future prospects in this rapidly evolving field, highlighting the direction for upcoming research.

Acoustotaxis‑based pump-less separation of highly motile human sperm by a SAW-in-capillary acoustofluidic platform

In artificial reproductive technologies mirroring in vivo fertilization, there is a correlation between sperm motility and fertilization outcomes. Here, we present a technology for separating sperm based on motility, which uses a biocompatible, pump-less, and simple acoustofluidic approach. Our developed and fabricated sperm separation configuration is an acoustofluidic platform consisting of a circular glass capillary tube mounted on top of a ZnO-based surface acoustic wave (SAW) device. It can separate highly motile sperm from small volumes of normal raw human semen samples. This configuration allows the generated traveling SAW to couple into the capillary, causing highly motile sperm cells to swim against the propagation direction of the traveling SAW along the capillary tube. We term this fascinating acoustic-induced sperm swimming behavior acoustotaxis in analogy with the well-known rheotaxis, in which sperm orientate to swim against a continuous fluid flow frequently generated by using an external pump in the microfluidic systems. Here, we benefit from the acoustotaxis for a pump-less separation of an effective highly motile sperm concentration from raw human semen samples at low volumes of up to 20–30 µL within a short period of about 4 minutes free from any centrifugation step. This sperm separation device exhibits a successful selection capability that leads to sperm progressive motility increase by 45 %, sperm curvilinear velocity by 23 %, sperm average path velocity by 69 %, and sperm linearity by 78 % in the selected cells in comparison with the raw sample. This acoustotaxic sperm selection separation approach provides an easy-to-use and effective method for the selection of highly motile sperm cells without adversely affecting sperm viability, paving the way for efficient and rapid sperm separation platforms, applicable for patients with low semen volumes, and up-scalable for a large volume of raw semen processing in a short time.

Separated reactant mix width across diffusion-dominated and hydrodynamically dominated interface mix in inertial confinement fusion implosions.

Diffusion-dominated mix in inertial confinement fusion (ICF) is characterized where the majority of the mix occurs in the immediate fuel-shell interface while hydrodynamic-dominated mix pulls shell material from farther away into the central fuel. A thin (150nm) separated reactants ICF mix platform is highly sensitive to the amount of mix from the first micron of shell-fuel interface. This fine-spatial resolution platform has revealed that material mix in moderate convergence (CR∼12) ICF implosions is dominated by a diffusion mechanism. This technique has now been expanded across a set of OMEGA ICF implosions, observing an increase in mix width and mix amount for cooler, slower, and more compressive implosions. Hydrodynamic simulations require a buoyancy-drag mix model to capture the increasing mix width, suggesting a transition between these two mix mechanisms.

Proportionally controlled dual-chiral covalent organic frameworks via thiol-ene click reaction for efficient enantioseparation

Developing a universally applicable and commercially hopeful chiral material is a significant challenge for the separation and analysis field. In this study, innovative dual-chiral CCOFs ([SH-β-CD-NALC]x-COFs) modified with 6-deoxy-6-mercapto-β-cyclodextrin (SH-β-CD) and N-acetyl-l-cysteine (NALC) are presented. These CCOFs were synthesized using a single, one-step bottom-up approach at room temperature, specifically designed for enantiomer recognition and separation. We investigated the effect of varying ratios of multiple chiral selectors in CCOFs on chiral recognition abilities through adsorption experiments for the first time. The precisely engineered [SH-β-CD-NALC]1/6-COF, with excellent stability, crystallinity, abundant chiral sites, and a greater specific surface area, was well suited as a chiral stationary phase (CSP) in various racemates separation. The results showed satisfactory resolution, column efficiency, stability, and reproducibility. In addition, mechanism studies have revealed that the dual-chiral COF can offer triple selectivity and achieve the effect where 1 + 1 is greater than 2. This work emphasized the advantages of dual-chiral COF in achieving racemic drug separation, providing a new approach for the development of high-performance chiral separation platforms in the future.

Covalent organic framework membranes with vertically aligned nanorods for efficient separation of rare metal ions

Covalent organic frameworks (COFs) have emerged as promising platforms for membrane separations, while remaining challenging for separating ions in a fast and selective way. Here, we propose a concept of COF membranes with vertically aligned nanorods for efficient separation of rare metal ions. A quaternary ammonium-functionalized monomer is rationally designed to synthesize COF layers on porous substrates via interfacial synthesis. The COF layers possess an asymmetric structure, in which the upper part displays vertically aligned nanorods, while the lower part exhibits an ultrathin dense layer. The vertically aligned nanorods enlarge contact areas to harvest water and monovalent ions, and the ultrathin dense layer enables both high permeability and selectivity. The resulting membranes exhibit exceptional separation performances, for instance, a Cs+ permeation rate of 0.33 mol m−2 h−1, close to the value in porous substrates, and selectivities with Cs+/La3+ up to 75.9 and 69.8 in single and binary systems, highlighting the great potentials in the separation of rare metal ions.

Scalable membrane-assisted ion exchange (MEM-IE) strategy for organic acid purification in biorefinery process

The transition towards a carbon-neutral society necessitates radical approaches in the bio-refinery pipeline, particularly in the production of organic acids. The current downstream process from a dilute fermentation broth is limited by the extensive use of acids and bases, along with heavy reliance on energy-intensive distillation. In this work, we propose an entirely membrane-based process to purify organic acids (e.g., gluconic acid) from a crude solution of catalytic dehydrogenation of glucose. To facilitate downstream purification, we introduce an innovative membrane-assisted ion exchange (MEM-IE) strategy, which is a scalable process that can protonate ionic compounds entirely in the solution phase. Instead of a solid ion exchange resin, a bulky yet soluble acidification agent is used to protonate the target compound, which can be easily separated via a size exclusion membrane. We selected non-toxic poly (4-styrene sulfonic acid) (H-PSS, 75 kDa) as the acidification agent to selectively protonate gluconate ions and to enable facile fractionation. The proposed MEM-IE strategy can overcome the scale-up limitation of traditional solid ion exchange resins and can be applied to many types of ionic compounds. The versatility of the proposed process was also demonstrated on formate and lactate compounds. A techno-economic evaluation using the Verberne cost model showed that the proposed process achieves an 80 % reduction in energy consumption compared to the fermentation-based process, and the return on investment (ROI) of a 330 ton-per-day plant was less than a year. The proposed membrane-based process for the purification of organic acids, particularly the MEM-IE strategy, offers a sustainable and energy-efficient downstream separation platform.

Multi-targets detection via combination of multi-stimulus-response engineered bacteria and hydrogel-based separation platform

Establishing a method similar to ICP-MS that can quantitatively analyze multiple heavy metals simultaneously, conveniently, and in situ is highly anticipated. In this study, we integrated the sensing elements of multiple targets and different fluorescence reporting elements to construct an engineered Escherichia coli. When these targets are present, the engineered bacteria can emit a fluorescent signal at the corresponding wavelength. To avoid the inability to accurately distinguish and quantify the content of each target due to the overlap of fluorescence signals when multiple targets coexist, a hydrogel-based separation platform similar to a separation column was constructed. The hydrogel platform can change the detection limit (LOD) and sensitivity by adjusting the adsorption strength towards different targets, so as to realize the differentiation and recognition of their respective detection signals. The LODs of this new detection method for Cd(II), Hg(II), As(III), and Pb(II) are 1.249, 0.380, 3.917, and 0.755 μg/L, respectively. In addition, this biosensor system was applied to detect coexisting Cd(II), Hg(II), As(III), and Pb(II) in actual samples with a recovery rate of 85.61–110.30 %, which is consistent with the classical ICP-MS detection results, confirming the accuracy and reliability of the method for detecting multiple heavy metal coexisting samples.

(Invited) Nanofluidic Ion Transport in Carbon Nanotube Porin Channels

Extreme spatial confinement in narrow fluidic channels strongly influences their transport properties and enables unconventional selectivity mechanisms that can often mimic some of the selectivity and transport characteristics of biological membrane channels. More than any modern nanomaterial, carbon nanotubes have enabled experimental platforms that can recreate such extreme confinement in a channel with defined geometry and controllable electronic properties. I will discuss ion transport in canon nanotube porin channels and show how confinement phenomena, coupled with the different electronic effects in these channels can shape their transport properties and ion selectivity characteristics. Overall, these observations contribute to our understanding of nanoscale transport and pave the way for developing a new generation of precision separation platforms for biomedical and industrial use.

Development of an advanced separation and characterization platform for mRNA and lipid nanoparticles using multi-detector asymmetrical flow field-flow fractionation.

In recent years, the use of lipid nanoparticles (LNPs) for delivery of messenger RNA (mRNA)-based therapies has gained substantial attention in the field of drug development. In such an application, multiple LNP attributes have to be carefully characterized to ensure product safety and quality, whereas accurate and efficient characterization of these complex mRNA-LNP formulations remains a challenging endeavor. Here, we present the development and application of an online separation and characterization platform designed for the isolation and in-depth analysis of mRNAs and mRNA-loaded LNPs. Our asymmetrical flow field-flow fractionation with a multi-detector (MD-AF4) method has demonstrated exceptional resolution between mRNA-LNPs and mRNAs, delivering excellent recoveries (over 70%) for both analytes and exceptional repeatability. Notably, this platform allows for comprehensive and multi-attribute LNP characterization, including online particle sizing, morphology characterization, and determination of encapsulation efficiency, all within a single injection. Furthermore, real-time online sizing by synchronizing multi-angle light scattering (MALS) and dynamic light scattering (DLS) presented higher resolution over traditional batch-mode DLS, particularly in differentiating heterogeneous samples with a low abundance of large-sized particles. Additionally, our method proves to be a valuable tool for monitoring LNP stability under varying stress conditions. Our work introduces a robust and versatile analytical platform using MD-AF4 that not only efficiently provides multi-attribute characterizations of mRNA-LNPs but also holds promise in advancing studies related to formulation screening, quality control, and stability assessment in the evolving field of nanoparticle delivery systems for mRNAs.

Kinematic mechanics study of silicon wafers and glass particles oscillatory separation based on friction coefficient differences

In this paper, the static friction coefficient of different particle sizes silicon wafers, glass particles and separation platform are measured by the plane method. Based on the force analysis of particle oscillatory separation process, the kinetic equation of particle oscillatory separation process is established, and the influence of factors such as particle size and friction coefficient on the motion trajectory of particle oscillatory separation process is analyzed. The research results indicate that the range of static friction coefficients between silicon wafers, glass particles, and separation platforms is different, but there are also overlapping parts. The kinetic equation indicates that the motion speed of particle oscillatory separation process is affected by factors such as the friction coefficient between particles and separation platforms, the inclination angle of separation platforms, and the amplitude of separation platforms. During the oscillatory separation process of silicon wafer glass mixed particles, silicon wafer particles with friction coefficients of 0.33–0.39 will become silicon wafer products, glass particles with friction coefficients of 0.22–0.31 will become glass products, and silicon wafer glass particles with overlapping friction coefficients of 0.310.33 will become intermediate products. To achieve better separation of silicon wafer and glass particles in the oscillatory separation process, it is necessary to take control measures to reduce the friction coefficient between the separation platform and silicon wafer and glass particles as much as possible.

Integrated MICROFASP Method with CZE-Based Fractionation Technique and NanoRPLC-ESI-MS/MS for a Comprehensive Proteomics Analysis of a Submicrogram Sample.

We report a loss-less two-dimensional (2D) separation platform that integrated capillary zone electrophoresis (CZE) fractionation and nanoRPLC-ESI-MS/MS for a comprehensive proteomics analysis of a submicrogram sample. Protein digest was injected into the linear polyacrylamide-coated capillary, followed by CZE separation. The schemes for collecting the fractions were carefully optimized to maximize the protein coverage. The peptide fractions were directly eluted into the autosampler insert vials, followed by the nanoRPLC-ESI-MS/MS analysis without lyophilization and redissolution, thus dramatically minimizing sample loss and potential contamination. The integrated platform generated 30,845 unique peptides and 5231 protein groups from 500 ng of a HeLa protein digest within 11.5 h (90 min CZE fractionation plus 10 h LC-MS analysis). Finally, the developed platform was used to analyze the protein digest prepared by the MICROFASP method with 1 μg of cell lysate as the starting material. Three thousand seven hundred ninety-six (N = 2, RSD = 4.95%) protein groups and 20,577 (N = 2, RSD = 7.89%) peptides were identified from only 200 ng of the resulted tryptic digest within 5.5 h. The results indicated that the combination of the MICROFASP method and the developed CZE/nanoRPLC-MS/MS 2D separation platform enabled comprehensive proteome profiling of a submicrogram biological sample. Data are available via ProteomeXchange with the identifier PXD052735.

Cryogel with Modular and Clickable Building Blocks: Toward the Ultimate Ideal Macroporous Medium for Bacterial Separation.

The lack of practical platforms for bacterial separation remains a hindrance to the detection of bacteria in complex samples. Herein, a composite cryogel was synthesized by using clickable building blocks and boronic acid for bacterial separation. Macroporous cryogels were synthesized by cryo-gelation polymerization using 2-hydroxyethyl methacrylate and allyl glycidyl ether. The interconnected macroporous architecture enabled high interfering substance tolerance. Nanohybrid nanoparticles were prepared via surface-initiated atom transfer radical polymerization and immobilized onto cryogel by click reaction. Alkyne-tagged boronic acid was conjugated to the composite for specific bacteria binding. The physical and chemical characteristics of the composite cryogel were analyzed systematically. Benefitting from the synergistic, multiple binding sites provided by the silica-assisted polymer, the composite cryogel exhibited excellent affinity toward S. aureus and Salmonella spp. with capacities of 91.6 × 107 CFU/g and 241.3 × 107 CFU/g in 0.01 M PBS (pH 8.0), respectively. Bacterial binding can be tuned by variations in pH and temperature and the addition of monosaccharides. The composite was employed to separate S. aureus and Salmonella spp. from spiked tap water, 40% cow milk, and sea cucumber enzymatic hydrolysate, which resulted in high bacteria separation and demonstrated remarkable potential in bacteria separation from food samples.

A fluorescent aptasensor for emetic Bacillus cereus detection based on DNA-functionalized magnetic separation coupled with rolling circle amplification

Foodborne pathogens have been a serious threat to human health and safety for a long time. However, the complex food substrate undoubtedly increases the difficulty of bacterial detection at low concentrations. How to effectively improve the sensitivity of bacterial detection is a major problem that needs to be solved. In this study, the aptamer of emetic Bacillus cereus (B. cereus) was used as the recognition molecule to construct a magnetic capture probe. Utilizing the strong affinity between target bacteria and the aptamer, a fluorescence sensor based on aptamer-rolling circle amplification (Apt-RCA) was established for the detection of emetic B. cereus in milk spiked samples. In this study, DNA-functionalized magnetic beads were first synthesized. The strong affinity between the aptamer and the target bacteria makes it to be used not only as an antibody substitute for capturing the target bacteria, but also to compete the complementary DNA (cDNA) strand of the aptamer on the DNA-functionalized magnetic bead as a primer for the subsequent RCA reaction. RCA reaction can produce RCA products rich in a large number of G-quadruplex sequences. The fluorescent dye thioflavin T (ThT) can bind to the G-quadruplex structure and produce an obvious fluorescence signal. The fluorescence signal amplification strategy based on the magnetic separation platform and RCA reaction successfully realized the sensitive detection of emetic B. cereus in actual sample. Under optimal conditions, the limits of detection (LODs) of pure bacterial solution and milk samples were 1.4 × 102 CFU/mL and 2.2 × 103 CFU/mL, respectively. This method has the advantages of short detection time, simple operation and good specificity, which provides a new way of thinking for the detection of foodborne pathogens.

Solvent-resistant isoporous membranes with tailored pore characteristics and on-demand sieving by site-selective hyper-crosslinking

Isoporous block copolymer membranes with high porosity and narrow pore size distribution have been viewed as ideal membrane platforms for precise separation of similarly sized particles or solutes. However, tailored made fabrication of solvent-resistant isoporous membranes with switchable pores and rigid pores for customizable sieving have been rarely reported. Herein, we show that site-selective hyper-crosslinking is effective and robust to prepare such membranes from polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP). The selective crosslinking in PS domains endows the membrane with excellent solvent resistance and structural stability. Since not participated in the crosslinking reaction, the P4VP brushes located in pore walls endow the crosslinked membranes with adaptive pore size, switchable permeance and tunable rejections that vary with Hansen solubility parameter of solvents. Moreover, by a facile while complete etching the P4VP from pores, the switchable performance is removed and resultant membranes show rigid pore characteristics and constant rejections. Crosslinked membranes with either switchable pores or rigid-likes pores exhibit superior long-term stability (30 days) in harsh solvents. This work presents a top-down method to construct highly stable isoporous membranes with both switchable and rigid pore characteristics from the same block copolymer, which will shed the light on precisely tailoring the pore size and pore rigidity for crosslinked isoporous membranes that will not only enable the tailored sieving but also the modelling of solvent flowing behaviours in nanopores.

Graphene oxide aerogels for adsorptive separation of aromatic hydrocarbons and cycloalkanes

Efficient separation of benzene and cyclohexane has critical importance for production of commodity chemicals, and is one of the most challenging separations in the industry. Physisorption by recyclable, porous solids has a significant potential in substituting energy-intensive azeotropic or extractive distillation methods. Reduced graphene oxide aerogels (rGOAs) are emerging materials holding great promise for connecting unique properties of 2D graphene with ordinary 3D materials. The benzene/cyclohexane separation on rGOAs self-assembled by the chemical reduction with l-ascorbic acid, sodium bisulphite and (for the first time) sodium dithionite was studied by dynamic gas adsorption methods, and the adsorption performance was analysed in relation to aerogels physicochemical properties. The aerogel reduced with sodium dithionite (rGOA_DTN) had the highest reduction degree and specific surface area (461.2 m2g-1), with the highest contribution of mesopores. It was also the sample with the uppermost uptake of benzene and cyclohexane. The binary component adsorption on rGOA_DTN resulted in the selectivity of the adsorption of benzene over cyclohexane of 2.1. Adsorption-desorption studies demonstrated the excellent thermal stability of the adsorbent in the long-run operation. Because the adsorption capacity did not correlate with the mesopores but with macropores surface area, the selectivity of the adsorption was attributed to the different physicochemical structure of aerogels surface. The benzene molecule interacted strongly by specific C-H···π interactions, while the cyclohexane molecule was excluded from the surface of aerogels because of its shape/size. Results demonstrated that rGOAs can be a versatile and flexible platform for adsorptive gas-phase hydrocarbons separation.