Machine Learning for Polymer Design to Enhance Pervaporation-Based Organic Recovery.

Pervaporation (PV) is an effective membrane separation process for organic dehydration, recovery, and upgrading. However, it is crucial to improve membrane materials beyond the current permeability-selectivity trade-off. In this research, we introduce machine learning (ML) models to identify high-potential polymers, greatly improving the efficiency and reducing cost compared to conventional trial-and-error approach. We utilized the largest PV data set to date and incorporated polymer fingerprints and features, including membrane structure, operating conditions, and solute properties. Dimensionality reduction, missing data treatment, seed randomness, and data leakage management were employed to ensure model robustness. The optimized LightGBM models achieved RMSE of 0.447 and 0.360 for separation factor and total flux, respectively (logarithmic scale). Screening approximately 1 million hypothetical polymers with ML models resulted in identifying polymers with a predicted permeation separation index >30 and synthetic accessibility score <3.7 for acetic acid extraction. This study demonstrates the promise of ML to accelerate tailored membrane designs.

Predicting Extraction Selectivity of Acetic Acid in Pervaporation by Machine Learning Models with Data Leakage Management.

The extraction of acetic acid and other carboxylic acids from water is an emerging separation need as they are increasingly produced from waste organics and CO2 during carbon valorization. However, the traditional experimental approach can be slow and expensive, and machine learning (ML) may provide new insights and guidance in membrane development for organic acid extraction. In this study, we collected extensive literature data and developed the first ML models for predicting separation factors between acetic acid and water in pervaporation with polymers' properties, membrane morphology, fabrication parameters, and operating conditions. Importantly, we assessed seed randomness and data leakage problems during model development, which have been overlooked in ML studies but will result in over-optimistic results and misinterpreted variable importance. With proper data leakage management, we established a robust model and achieved a root-mean-square error of 0.515 using the CatBoost regression model. In addition, the prediction model was interpreted to elucidate the variables' importance, where the mass ratio was the topmost significant variable in predicting separation factors. In addition, polymers' concentration and membranes' effective area contributed to information leakage. These results demonstrate ML models' advances in membrane design and fabrication and the importance of vigorous model validation.

Effect of quorum quenching on biofouling control and microbial community in membrane bioreactors by Brucella sp. ZJ1.

Quorum quenching (QQ) has been demonstrated to be a novel technique for controlling biofouling in membrane bioreactors (MBRs), as it can significantly inhibit biofilm formation by disrupting quorum sensing (QS). The exploration of new QQ bacterial strains and the evaluation of their performance in mitigating membrane fouling in MBR systems is significant. In this study, an efficient QQ strain, Brucella sp. ZJ1 was encapsulated in alginate beads and evaluated for its ability to mitigate biofouling. The findings revealed that MBR with QQ beads extended the operation time by 2-3 times without affecting pollutant degradation. QQ beads maintained approximately 50% QQ activity after more than 50 days operation, indicating a long-lasting and endurable QQ effect. The QQ effect reduced extracellular polymeric substance (EPS) production especially in terms of polysaccharide and protein by more than 40%. QQ beads in the MBR also reduced the cake resistance and the irreversible resistance of membrane biofouling. Metagenomic sequencing suggests that QQ beads suppressed the QS effect and increased the abundance of QQ enzyme genes, ultimately inducing efficient membrane biofouling control.

Metal Azolate Coordination Polymer-Enabled High Payload and Non-Destructive Enzyme Immobilization for Biocatalysis and Biosensing.

The biomineralized metal-organic frameworks (MOFs) as protective layers help enhance the robustness of enzymes for biocatalysis. Despite great efforts, it is still challenging to develop a recyclable system with high payload and tolerance to harsh conditions. Here, we report a facile surface charge-independent strategy based on Zn-based coordination polymer (ZnCP) for nondestructive immobilization of enzyme. The ZnCP outcompetes most of the previously reported MOFs, in terms of high-payload enzyme packaging. Moreover, benefiting from the hydrophilicity of ZnCP, the entrapped enzymes (e.g., positive cytochrome C and negative glucose oxidase) maintained high catalytic activity, resembling their native counterparts. Notably, compared with ZIF-8, such enzyme-incorporated ZnCP (enzyme@ZnCP) is more tolerant to acidic pH, which imparts the enzyme with good recyclability, even in acid species-generated catalytic reactions, thus broadening its application in biocatalysis. The feasibility of enzyme@ZnCP for protein packaging, enzyme cascade catalysis, and biosensing was also validated. Altogether, enzyme@ZnCP demonstrates high enzyme payload, operational stability, and preservation of enzymatic activity, affording a versatile platform to accommodate bioactive enzyme for biocatalysis and biosensing.

ES&T in the 21st Century: A Data-Driven Analysis of Research Topics, Interconnections, And Trends in the Past 20 Years.

Environmental Science & Technology (ES&T) has served a leadership role in reporting advanced and significant research findings for decades and accumulated tremendous amount of high-quality literature. In this study, we developed tailored text mining methods and analyzed 29 188 papers published in ES&T from 2000 to 2019, and we performed data-driven analyses to reveal some critical information and guidance on what has been published, what topical changes have evolved, and what are the areas that deserve additional attention. While top research keywords remained stable (water, sorption, soil, emiss, oxid, exposur), the trending up and emerging keywords showed clear shift over the years. Keywords related to nanobased materials (nanoparticl, nanomateri, carbon nanotub), climate and energy (climat, ch4, greenhouse gas emiss, mitig, energi), and health (exposur, health, ingest) demonstrated the strongest uptrend in the past 10 years, while plastics and PFAS were among clear emerging topics in the past 5 years. Co-occurrence analysis showed distinct associations between media (water, soil, air, sediment), chemicals (pcb, humic subst, particulate matt), processes (sorption, remov, degrad), and properties (kinet, mechan, speciat). Furthermore, a rule-based classification deciphered trends, distributions, and interconnections of articles based on either monodomains (air, soil, solid waste, water, and wastewater) or multidomains. It found water and wastewater cross-discipline articles tended to have higher citation values, while air domain tended to stand alone. Water and air monodomains consistently increased their shares in publications (together 56.3% in 2019), while shares of soil studies gradually declined. This study provides new data-driven methods on literature mining and offers unique insights on environmental research landscape and opportunities.

Unsupervised aided investigation on the associations between municipal solid waste characteristics and socio-economic conditions.

Better municipal solid waste (MSW) management can help to address environmental concerns and supports economic and social development. Because MSW characteristics can change over time, management strategies should also evolve and be applied correspondingly. However, many previous studies have focused on MSW characterization or investigated specific management strategies for a target MSW. Few studies have assessed the spatial variations of MSW characteristics and socio-economic (SE) conditions as well as their associations. This study evaluated the feasibility of using an integrated unsupervised method (cluster analysis and cross-tabulation analysis) to explore these topics for MSW management. Results suggest that the integrated method can successfully help to reveal key information. Seven jointed MSW-SE scenarios were investigated based on 259 individual observations of Taiwan. Associations between MSW compositions and SE conditions were identified statistically significant for four MSW-SE scenarios. In general, the general SE type (SE1) is very likely to generate high food wastes and other combustible, low paper, wood, and rubber wastes (MSW1). The small island SE type (SE3) is more likely to produce high paper and low wood, rubber, textile, and other noncombustible wastes (MSW2). Overall, the method applied in this study could help to reveal statistical associations between MSW and SE, which can help decision-makers comprehend underlying facts and develop effective management strategies.

Metal-Ligand Coordination Nanomaterials for Biomedical Imaging.

Over the past two decades, amorphous nanoscale coordination polymers (NCPs) and crystalline nanoscale metal-organic frameworks (NMOFs) have emerged as attractive nanomaterials in biomedical applications, especially in drug delivery, biomedical imaging, and biosensing. The biodegradability, tunable composition, and feasible functionality of NCPs/NMOFs make them excellent contrast agents or nanocarriers for biomedical imaging, including magnetic resonance (MR) imaging, positron emission tomography (PET), computed tomography (CT), optical imaging, and photoacoustic (PA) imaging. In this Topical Review, we will summarize the recent advances of NCPs/NMOFs in biomedical imaging with emphasis on research over the past three years. A variety of imaging technologies based on NCPs/NMOFs will be discussed, followed by the introduction of the application of NCPs/NMOFs in multimodal imaging where optical/MR imaging is highlighted. In the final part, we will make concluding remarks and point out the challenges and prospects for the further development in this area of research.

Living and Conducting: Coating Individual Bacterial Cells with In†Situ Formed Polypyrrole.

Coating individual bacterial cells with conjugated polymers to endow them with more functionalities is highly desirable. Here, we developed an in situ polymerization method to coat polypyrrole on the surface of individual Shewanella oneidensis MR-1, Escherichia coli, Ochrobacterium anthropic or Streptococcus thermophilus. All of these as-coated cells from different bacterial species displayed enhanced conductivities without affecting viability, suggesting the generality of our coating method. Because of their excellent conductivity, we employed polypyrrole-coated Shewanella oneidensis MR-1 as an anode in microbial fuel cells (MFCs) and found that not only direct contact-based extracellular electron transfer is dramatically enhanced, but also the viability of bacterial cells in MFCs is improved. Our results indicate that coating individual bacteria with conjugated polymers could be a promising strategy to enhance their performance or enrich them with more functionalities.

An electrochemical-TUNEL method for sensitive detection of apoptotic cells.

An electrochemical-TUNEL method was developed for a cell sensor. A 3-D bio-interface based on CNT@PDA-FA was employed in the cytosensor, which significantly improved the cell capture. By coupling with a QD-based nanoprobe and electrochemical stripping analysis, the cytosensor exhibited attractive performance for detection of apoptotic cells.

An upconversion fluorescent resonant energy transfer biosensor for hepatitis B virus (HBV) DNA hybridization detection.

A novel fluorescent resonant energy transfer (FRET) biosensor was fabricated for the detection of hepatitis B virus (HBV) DNA using poly(ethylenimine) (PEI) modified upconversion nanoparticles (NH2-UCNPs) as energy donor and gold nanoparticles (Au NPs) as acceptor. The PEI modified upconversion nanoparticles were prepared directly with a simple one-pot hydrothermal method, which provides high quality amino-group functionalized UCNPs with uniform morphology and strong upconversion luminescence. Two single-stranded DNA strands, which were partially complementary to each other, were then conjugated with NH2-UCNPs and Au NPs. When DNA conjugated NH2-UCNPs and Au NPs are mixed together, the hybridization between complementary DNA sequences on UCNPs and Au NPs will lead to the quenching of the upconversion luminescence due to the FRET process. Meanwhile, upon the addition of target DNA, Au NPs will leave the surface of the UCNPs and the upconversion luminescence can be restored because of the formation of the more stable double-stranded DNA on the UCNPs. The sensor we fabricated here for target DNA detection shows good sensitivity and high selectivity, which has the potential for clinical applications in the analysis of HBV and other DNA sequences.

The effects of nanoplastics and microcystin-LR coexposure on Aristichthys nobilis at the early developmental stages.

Nanoplastics (NPs) and microcystin-LR (MC-LR) are two common and harmful pollutants in water environments, especially at aquafarm where are full of plastic products and algae. It is of great significance to study the toxic effects and mechanisms of the NPs and/or MC-LR on fish at the early stage. In this study, the embryo and larvae of a filtering-feeding fish, Aristichthys nobilis, were used as the research objects. The results showed that the survival and hatching rates of the embryo were not significantly affected by the environmental concentration exposure of these two pollutants. Scanning electron microscopy (SEM) observation displayed that NPs adhered to the surface of the embryo membrane. Transcriptomic and bioinformatic analyses revealed that the NPs exposure activated neuromuscular junction development and skeletal muscle fiber in larvae, and affected C5-Branched dibasic acid metabolism. The metabolic and biosynthetic processes of zeaxanthin, xanthophyll, tetraterpenoid, and carotenoid were suppressed after the MC-LR exposure, which was harmful to the retinol metabolism of fish. Excessive production of superoxide dismutase (SOD) was detected under the MC-LR exposure. The MC-LR and NPs coexposure triggered primary immunodeficiency and adaptive immune response, leading to the possibility of reduced fitness of A.nobilis during the development. Collectively, our results indicate that environmental concentration NPs and MC-LR coexposure could cause toxic damage and enhance sick risk in A.nobilis, providing new insights into the risk of NPs and MC-LR on filtering-feeding fish.

Minimalist Nanovaccine with Optimized Amphiphilic Copolymers for Cancer Immunotherapy.

Cancer vaccines with the ability to elicit tumor-specific immune responses have attracted significant interest in cancer immunotherapy. A key challenge for effective cancer vaccines is the spatiotemporal codelivery of antigens and adjuvants. Herein, we synthesized a copolymer library containing nine poly(ethylene glycol) methyl ether methacrylate-co-butyl methacrylate-co-2-(azepan-1-yl)ethyl methacrylate (PEGMA-co-BMA-co-C7AMA) graft copolymers with designed proportions of different components to regulate their properties. Among these polymers, C-25, with a C7AMA:BMA ratio at 1.5:1 and PEG wt % of 25%, was screened as the most effective nanovaccine carrier with enhanced ability to induce mouse bone marrow-derived dendritic cell (BMDC) maturation. Additionally, RNA-sequencing (RNA-Seq) analysis revealed that C-25 could activate dendritic cells (DCs) through multisignaling pathways to trigger potent immune effects. Then, the screened C-25 was used to encapsulate the model peptide antigen, OVA257-280, to form nanovaccine C-25/OVA257-280. It was found that the C-25/OVA257-280 nanovaccine could effectively facilitate DC maturation and antigen cross-presentation without any other additional adjuvant and exhibited excellent prophylactic efficacy in the B16F10-OVA tumor model. Moreover, in combination with antiprogrammed cell death protein-ligand 1 (anti-PD-L1), the C-25/OVA257-280 nanovaccine could significantly delay the growth of pre-existing tumors. Therefore, this work developed a minimalist nanovaccine with a simple formulation and high efficiency in activating tumor-specific immune responses, showing great potential for further application in cancer immunotherapy.

Ultrasensitive immunoassay based on dual signal amplification of the electrically heated carbon electrode and quantum dots functionalized labels for the detection of matrix metalloproteinase-9.

A dual signal amplification strategy was designed for electrochemical detection of matrix metalloproteinase-9 with the integration of electrically heated carbon electrode technique and quantum dots labels.

Graphene quantum dots derived from carbon fibers.

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications.

A label-free cytosensor for the enhanced electrochemical detection of cancer cells using polydopamine-coated carbon nanotubes.

An electrochemical, label-free method was developed to detect folate receptor positive tumor cells by specific recognition of a polydopamine-coated carbon nanotubes-folate nanoprobe to cell-surface folate receptors. This strategy offers great promise to extend its application in studying the interaction of ligand and cell-surface receptor.

Fabrication of silica/PDMS hybrid nanoparticles by a novel solvent adjustment route.

The silica/polydimethylsilane (PDMS) hybrid nanoparticles were successfully synthesized by a novel solvent adjustment route. The as-prepared hybrid nanoparticles were characterized by transmission electron microscopy, UV-vis spectra, and IR spectra. The possible mechanism for the formation of silica/PDMS nanoparticles was discussed. The adjustment of solvents is a very important factor since it could tune the surface ligands and improve the coordination ability. On the other hand, it could also tune the interaction between precursors, intermediate or the target hybrid materials and guarantee the monodispersion of prepared nanoparticles. With the merits of PDMS and silica, the as-prepared SiO2-PDMS hybrid nanoparticles have a good application in hard coating material.

Lipid droplet-hitchhiking probe creates Trojan foam cells for fluorescence/photoacoustic imaging of atherosclerotic plaques.

Since atherosclerosis, a disease characterized by abnormal arterial lipid deposition, may lead to fatal cardiovascular diseases, imaging of atherosclerotic plaques is of great value for their pathological assessment. In this study, we propose a lipid droplet (LD)-hitchhiking strategy to in situ create Trojan foam cells for fluorescence/photoacoustic imaging of atherosclerotic plaques via homologous targeting effect. In our design, functional liposomes (DCP liposomes) composed of phospholipid dioleoylphosphatidylserine (DOPS), a novel LD inducer we found, and Cypate-PC, a synthesized lipid-like molecular probe, have demonstrated great capability of inducing LDs in monocytes/macrophages while being enveloped into the resulting Trojan foam cells. Taking advantage of homologous targeting effect, the imaging probe hitchhikes on the LDs in Trojan foam cells for targeted transport to the plaque sites. Moreover, the confinement in highly hydrophobic LDs endows the imaging probe with high efficiency in light absorption, enabling greatly intensified fluorescence/photoacoustic signals. The DCP liposomes have shown great potency in inducing the generation of Trojan foam cells, and eventually ex vivo fluorescence imaging and in vivo photoacoustic imaging of atherosclerotic plaques. The proposed strategy provides more insights into the design of targeted imaging methodologies, and also an effective avenue to facilitate the evaluation and subsequent treatment of atherosclerotic plaques.

Long-term cell culture and electrically in situ monitoring of living cells based on a polyaniline hydrogel sensor.

Accurate, in situ and long-term electrically monitoring of cell development plays an important role in cell study, which brings in challenges in terms of biocompatibility, processability, and sensing capability of electrochemical sensors. Based on biocompatible conductive polyaniline (PAni) hydrogels, we constructed a flexible sensor with flexible carbon cloth for electrical analysis of living cells. The carbon fiber substrate modified with conductive PAni hydrogels was selected as the electrode to promote the current collection of the sensor. The three dimensional nanostructured mesoporous matrix of PAni hydrogels is favorable for in situ generation of catalytic Pt nanoparticles and cell growth. With these hierarchically nanostructured features, the hydrogel electrochemical sensor was endowed with high sensitivity and selectivity in the detection of H2O2 (with a low detection limit of 1.6 µM in 0.01 M PBS and a wide linear range from 10 µM to 10 mM), and good biocompatibility for cell growth as long as 5 days. The accurate detection of H2O2 released from cells enabled us to differentiate the physiological states of cells and imitate the different stimuli-responsive behavior, which can provide real-time information on cell biological events. With outstanding biocompatibility, operability and repeatability, this strategy can be expanded to the fields of other biosensor fabrication and cell-related biomarker monitoring, which exhibits a broad application potential in bioanalysis catering to new generation sensors.

Electrochemical immunosensor for simultaneous detection of dual cardiac markers based on a poly(dimethylsiloxane)-gold nanoparticles composite microfluidic chip: a proof of principle.

BACKGROUND: The emergence of microfluidic immunosensors has provided a promising tool for improving clinical diagnoses. We developed an electrochemical immunoassay for the simultaneous detection of cardiac troponin I (cTnI) and C-reactive protein (CRP), based on microfluidic chips. METHODS: The quantitative methodology was based on ELISA in poly(dimethylsiloxane)-gold nanoparticle composite microreactors. CdTe and ZnSe quantum dots were bioconjugated with antibodies for sandwich immunoassay. After the CdTe and ZnSe quantum dots were dissolved, Cd(2+) and Zn(2+) were detected by square-wave anodic stripping voltammetry to enable the quantification of the 2 biomarkers. The 2 biomarkers were measured in 20 human serum samples by using the proposed method and commercially available methods. RESULTS: This immunosensor allowed simultaneous detection of serum cTnI and CRP. The linear range of this assay was between 0.01 and 50 µg/L and 0.5 and 200 µg/L, with the detection limits of approximately 5 amol and approximately 307 amol in 30-µL samples corresponding to cTnI and CRP, respectively. Slopes close to 1 and the correlation coefficient over 0.99 were obtained for both analytes. CONCLUSIONS: This strategy demonstrates a proof of principle for the successful integration of microfluidics with electrochemistry that can potentially provide an alternative to protein detection in the clinical laboratory.

DC electrokinetic particle transport in an L-shaped microchannel.

Electrokinetic transport of particles through an L-shaped microchannel under DC electric fields is theoretically and experimentally investigated. The emphasis is placed on the direct current (DC) dielectrophoretic (DEP) effect arising from the interactions between the induced spatially nonuniform electric field around the corner and the dielectric particles. A transient multiphysics model is developed in an arbitrary Lagrangian-Eulerian (ALE) framework, which comprises the Navier-Stokes equations for the fluid flow and the Laplace equation for the electrical potential. The predictions of the DEP-induced particle trajectory shift in the L-shaped microchannel are in quantitative agreement with the obtained experimental results. Numerical studies also show that the DEP effect can alter the angular velocity and even the direction of the particle's rotation. Further parametric studies suggest that the L-shaped microfluidic channel may be utilized to focus and separate particles by size via the induced DEP effect.