Probabilistic Estimation of Airborne Micro- and Nanoplastic Intake in Humans.

Little research exists on the magnitude, variability, and uncertainty of human exposure to airborne micro- and nanoplastics (AMNPs), despite their critical role in human exposure to MNPs. We probabilistically estimate the global intake of AMNPs through three main pathways: indoor inhalation, outdoor inhalation, and ingestion during indoor meals, for both children and adults. The median inhalation of AMPs is 1,207.7 (90% CI, 42.5-8.48 × 104) and 1,354.7 (90% CI, 47.4-9.55 × 104) N/capita/day for children and adults, respectively. The annual intake of AMPs is 13.18 mg/capita/a for children and 19.10 mg/capita/a for adults, which is approximately one-fifth and one-third of the mass of a standard stamp, assuming a consistent daily intake of medians. The majority of AMP number intake occurs through inhalation, while the ingestion of deposited AMPs during meals contributes the most in terms of mass. Furthermore, the median ANP intake through outdoor inhalation is 9,638.1 N/day (8.23 × 10-6 µg/d) and 5,410.6 N/day (4.62 × 10-6 µg/d) for children and adults, respectively, compared to 5.30 × 105 N/day (5.79 × 10-4 µg/d) and 6.00 × 105 N/day (6.55 × 10-4 µg/d) via indoor inhalation. Considering the increased toxicity of smaller MNPs, the significant number of ANPs inhaled warrants great attention. Collaborative efforts are imperative to further elucidate and combat the current MPN risks.

MdMYB88 and MdMYB124 Enhance Drought Tolerance by Modulating Root Vessels and Cell Walls in Apple.

Water deficit is one of the main limiting factors in apple (Malus × domestica Borkh.) cultivation. Root architecture plays an important role in the drought tolerance of plants; however, research efforts to improve drought tolerance of apple trees have focused on aboveground targets. Due to the difficulties associated with visualization and data analysis, there is currently a poor understanding of the genetic players and molecular mechanisms involved in the root architecture of apple trees under drought conditions. We previously observed that MdMYB88 and its paralog MdMYB124 regulate apple tree root morphology. In this study, we found that MdMYB88 and MdMYB124 play important roles in maintaining root hydraulic conductivity under long-term drought conditions and therefore contribute toward adaptive drought tolerance. Further investigation revealed that MdMYB88 and MdMYB124 regulate root xylem development by directly binding MdVND6 and MdMYB46 promoters and thus influence expression of their target genes under drought conditions. In addition, MdMYB88 and MdMYB124 were shown to regulate the deposition of cellulose and lignin root cell walls in response to drought. Taken together, our results provide novel insights into the importance of MdMYB88 and MdMYB124 in root architecture, root xylem development, and secondary cell wall deposition in response to drought in apple trees.

Layer-by-layer assembled PEI-based vector with the upconversion luminescence marker for gene delivery.

The upconversion luminescence (UCL) marker based on upconversion nanoparticles (UCNPs) shows unique advantages over traditional fluorescence markers, such as enhanced tissue penetration, better photostability, and less autofluorescence. Herein, we constructed a new UCL gene-delivery nonviral vector via layer-by-layer self-assembly of poly(ethylene imine) (PEI) with UCNPs. To reduce the cytotoxicity of PEI, citric acid (CA) was introduced for aqueous modification, and PEI assembly was introduced on the UCNP surface. Our data show that the nonviral vector for UCL gene-delivery demonstrates excellent photostability, low toxicity, and good stability under physiological or serum conditions and can strongly bind to DNA. Moreover, this UCL PEI-based vector could serve as a promising fluorescent gene-delivery carrier for theranostic applications.

Preparation of polydopamine nanocapsules in a miscible tetrahydrofuran-buffer mixture.

A miscible tetrahydrofuran-tris buffer mixture has been used to fabricate polydopamine hollow capsules with a size of 200 nm and with a shell thickness of 40 nm. An unusual non-emulsion soft template mechanism has been disclosed to explain the formation of capsules. The results indicate that the capsule structure is highly dependent on the volume fraction of tetrahydrofuran as well as the solvent, and the shell thickness of capsules can be controlled by adjusting the reaction time and dopamine concentration.

Preparation of Hemocompatible Poly(lactic-co-glycolic acid)-F127 Nanospheres and Their Application to Biosensor for Analysis of Whole Blood.

In this paper, the novel poly(lactic-co-glycolic acid)-F127 nanospheres (PLGA-F127 NSs) were synthesized and used to establish an amperometric glucose biosensor that can be applied in whole blood directly. This property of glucose biosensor was based on the antibiofouling property of PLGA-F127 NSs. More details of preparing PLGA-F127 NSs and immobilizing glucose oxidase (GOx) on (PLGA-F127)/glass carbon electrode (GCE) were presented. Then, the electrochemical behaviors of the biosensor in whole blood were studied. The cyclic voltammetric results indicated that GOx immobilized on PLGA-F127 NSs exhibited direct electron transfer reaction, which led to stable amperometric biosensing for glucose with a detection limit of 5.57 x 10(-6) M (S/N = 3). The glucose biosensor did not respond to ascorbic acid (AA) and uric.acid (UA) at their concentration normally encountered in blood. The development of materials science will bring significant input to high-performance biosensors relevant to diagnostics and therapy of interest for human health.

Atmospheric deposition of microplastics at a western China metropolis: Relationship with underlying surface types and human exposure.

The issue of atmospheric microplastic (AMP) contamination is gaining increasing attention, yet the influencing factors and human exposure are not well-understood. In this study, atmospheric depositions were collected in the megacity of Chengdu, China, to investigate the pollution status and spatial disparities in AMP distribution. The relationship between AMP abundance and underlying surface types was then analyzed with the aid of back trajectory simulation. Additionally, a probabilistic estimation of human exposure to AMP deposition during outdoor picnics was provided, followed by the calculation of AMP loading into rivers. Results revealed that the mean deposition flux ranged within 207.1-364.0 N/m2/d (14.17-33.75 µg/m2/d), with significantly larger AMP abundance and sizes in urban compared to rural areas. Areas of compact buildings played an important role in contributing to both fibrous and non-fibrous AMP contamination from urban to rural areas, providing new insight into potential sources of pollution. This suggests that appropriate plastic waste disposal in compact building areas should be prioritized for controlling AMP pollution. Besides, the median ingestion of deposited AMPs during a single picnic was 34.9 N/capita/hour (3.03 × 10-3 µg/capita/hour) for urban areas and 17.8 N/capita/hour (7.74 × 10-4 µg/capita/hour) for suburbs. Furthermore, the worst-case scenario of AMPs loading into rivers was investigated, which could reach 170.7 kg in summertime Chengdu. This work could contribute to a better understanding of the status of AMP pollution and its sources, as well as the potential human exposure risk.

Response of aerobic granular sludge under acute inhibition by polystyrene microplastics: Activity, aggregation performance, and microbial analysis.

In this study, the activity, aggregation performance, microbial community and functional proteins of aerobic granular sludge (AGS) in response to acute inhibition by different concentrations of polystyrene microplastics (PS-MPs) were investigated. As the PS-MPs concentration increased from 0 mg/L to 200 mg/L, the specific nitrogen removal rate and the activity of enzymes were inhibited. The inhibition of specific nitrite reduction rate (SNIRR) and specific nitrate reduction rate (SNRR) was most obvious at the PS-MPs concentration of 100 mg/L, and that of nitrite reductase (NIR) and nitrate reductase (NR) was most obvious at the concentration of 50 mg/L. But the inhibitory effects were mitigated at the concentration of 200 mg/L. The increase of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) indicated that the cells were damaged with the increase of PS-MPs concentration. The content of proteins and polysaccharides in extracellular polymeric substances (EPS) decreased, especially the polysaccharides were more affected. Analysis of zeta potential, hydrophobicity and surface thermodynamics of AGS revealed that addition of PS-MPs was unfavorable for AGS aggregation. It was also found that bacteria genera associated with EPS secretion and nitrogen removal functions were inhibited, while functions associated with cell metabolism, protein synthesis and cell repair were enhanced. This also confirmed that acute inhibition of PS-MPs had a detrimental effect on the nitrogen removal and aggregation performance of AGS. This study can provide theoretical support for the operation of AGS reactors under microplastics impact load.

Structural evolution of low-molecular-weight poly(ethylene oxide)-block-polystyrene diblock copolymer thin film.

The structural evolution of low-molecular-weight poly(ethylene oxide)-block-polystyrene (PEO-b-PS) diblock copolymer thin film with various initial film thicknesses on silicon substrate under thermal annealing was investigated by atomic force microscopy, optical microscopy, and contact angle measurement. At film thickness below half of the interlamellar spacing of the diblock copolymer (6.2 nm), the entire silicon is covered by a polymer brush with PEO blocks anchored on the Si substrate due to the substrate-induced effect. When the film is thicker than 6.2 nm, a dense polymer brush which is equal to half of an interlamellar layer was formed on the silicon, while the excess material dewet this layer to form droplets. The droplet surface was rich with PS block and the PEO block crystallized inside the bigger droplet to form spherulite.

Mitigating airborne microplastics pollution from perspectives of precipitation and underlying surface types.

The issue of airborne microplastics (AMPs) pollution is receiving increasing attention, but effective solutions are still limited. In this study, AMPs were collected in pairs from an open space and under a tree (Ficus virens) in the suburb of Chengdu, southwest China, to investigate the current pollution status. The meteorological factors and underlying surface types were analyzed to investigate whether these factors could influence and mitigate the pollution of AMPs. The results showed that the fibrous AMPs accounted for the vast majority and the dominant polymers were polypropylene-polyethylene (PP-PE) and polypropylene (PP), with an average deposition flux of AMPs of 192 n/m2/d (22.41 µg/m2/d). Rainfall was found to have the prolonged scavenging efficiency for AMPs, which could extend to 8 to 48 hours after the end of rainfall, and this is a new insight into the relationship with meteorological factors. Interactions between the key underlying surface types and AMPs were also studied. The representative tree species (Ficus virens) had a low interception rate of 6.25% for AMPs and retained mainly small-sized AMPs and more fibers. The masses of AMPs loaded into Chengdu rivers could reach 1149 kg annually, with the unit mass load of 13.6 kg/km2 in urban rivers and 8.2 kg/km2 in suburban rivers. The masses intercepted by trees and bushes throughout the city only offset the masses loading in rivers, and open or sparse buildings were found to be sensitive areas for AMPs, which indicated the urgent need to control and mitigate the pollution of AMPs, especially in these sensitive areas. This work comprehensively analyzed the AMPs pollution from various perspectives and attempted to find ways to mitigate this pollution.

Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.

The anionic polyurethane nanoparticles (APU-NPs) were obtained by an emulsion polymerization method. It was found that the average size of the prepared APU-NPs is about 84 nm, and the APU-NPs have zeta-potential of -38.9 mV. The bulk characterization of synthesized APU-NPs was investigated by FTIR. The blood compatibility of APU-NPs was characterized by in vitro for coagulation tests, complement activation, platelet activation, cytotoxicity experiments, and hemolysis assay. The results showed that the APU-NPs synthesized in this paper are blood compatible with low level of cell cytotoxicity, and the results were significant for their potential use in vivo.

Are we ignoring the role of urban forests in intercepting atmospheric microplastics?

Occurrences and characteristics of atmospheric microplastics(MPs) have been widely studied by previous studies, while the mitigation of airborne MPs pollution was not well understood. In this study, atmospheric samples of MPs were collected in pairs on the rooftop and under trees composed of representative afforested species Ficus microcarpa in Chengdu, Southwest China, to explore whether trees could intercept MPs. Results showed that the daily life of human beings and textile industries of urban areas were sources of airborne MPs as revealed by chemical compositions and air trajectories. The trees with the high coverage degree (88%) and large three-dimensional spaces formed by leaves did have the ability to intercept high-density MPs with small sizes under the force of gravity. The intercepting rate was about 16.3%, 12,593 n/m2 of fibers and 347.69 kg of MPs could be intercepted by urban forests for one year. However, threshold values of rainfall intensity (12 mm/d) and rainfall amounts (14 mm) were found to limit the intercepting mechanism, and intercepting effects decrease with the increase of rainfall amounts (r =-0.71). This work provides quantitative evidence that elucidated urban forests may act as receptors of airborne MPs, thus improving the air quality and human health.

Bioreducible micelles self-assembled from amphiphilic hyperbranched multiarm copolymer for glutathione-mediated intracellular drug delivery.

A new type of biodegradable micelles for glutathione-mediated intracellular drug delivery was developed on the basis of an amphiphilic hyperbranched multiarm copolymer (H40-star-PLA-SS-PEP) with disulfide linkages between the hydrophobic polyester core and hydrophilic polyphosphate arms. The resulting copolymers were characterized by nuclear magnetic resonance (NMR), Fourier transformed infrared (FTIR), gel permeation chromatography (GPC), and differential scanning calorimeter (DSC) techniques. Benefiting from amphiphilic structure, H40-star-PLA-SS-PEP was able to self-assemble into micelles in aqueous solution with an average diameter of 70 nm. Moreover, the hydrophilic polyphosphate shell of these micelles could be detached under reduction-stimulus by in vitro evaluation, which resulted in a rapid drug release due to the destruction of micelle structure. The glutathione-mediated intracellular drug delivery was investigated against a Hela human cervical carcinoma cell line. Flow cytometry and confocal laser scanning microscopy (CLSM) measurements demonstrated that H40-star-PLA-SS-PEP micelles exhibited a faster drug release in glutathione monoester (GSH-OEt) pretreated Hela cells than that in the nonpretreated cells. Cytotoxicity assay of the doxorubicin-loaded (DOX-loaded) micelles indicated the higher cellular proliferation inhibition against 10 mM of GSH-OEt pretreated Hela cells than that of the nonpretreated ones. As expected, the DOX-loaded micelles showed lower inhibition against 0.1 mM of buthionine sulfoximine (BSO) pretreated Hela cells. These reduction-responsive and biodegradable micelles show a potential to improve the antitumor efficacy of hydrophobic chemotherapeutic drugs.

[Synthesis and fluorescence properties of thermo-responsive microgel nanoparticles].

In the present paper, the preparation and properties of Eu(III) on poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) were described. At first, P(NIPAM-co-AAc) microgel nanoparticles were prepared by the precipitation copolymerization of N-isopropylacrylamide with acrylic acid in the presence of N, N-methylenebisacrylamide in water. The morphology and size of the P(NIPAM-co-AAc) nanoparticles were characterized by the scanning electron microscope (SEM) method. The result of SEM shows that the sample is uniformly sized spherical particle and the average particle size of the P(NIPAM-co-AAc) is about 365 nm. Then, EuCl3 was chosen to interact with P(NIPAM-co-AAc) nanoparticles and formed the complex of P(NIPAM-co-AAc)-Eu(III). The complex was characterized by Fourier transform infrared spectroscopy, ultraviolet-visible and fluorescence spectroscopy. It was found that the complex shows thermo-responsive fluorescence from the experimental results. There exists a energy transfer between the polymer ligand and the Eu(III), which can enhance fluorescence emission of the polymer ligand and Eu(III) at the same time. The LCST of P(NIPAM-co-AAc) containing Eu(III) has changed little after the formation of the complex of P(NIPAM-co-AAc)-Eu(III). Therefore, the complex can be used for developing the new applications in biomedical and fluorescence field.

Codelivery of doxorubicin and camptothecin by dual-responsive unimolecular micelle-based ß-cyclodextrin for enhanced chemotherapy.

Tumor microenvironment (TME)-induced drug delivery technology is a promising strategy for improving low drug accumulation efficiency, short blood circulation and weak therapeutic effect. In this work, a dual-responsive (reduction- and pH-responsive) polyprodrug nanoreactor based on ß-cyclodextrin (ß-CD) was constructed for combinational chemotherapy. Specifically, the dual-responsive star polymeric prodrug was synthesized by atom transfer radical polymerization (ATRP) based on a starburst initiator of ß-CD-Br. The obtained polyprodrug contained a hydrophilic chain of poly-(ethylene glycol) methyl ether methacrylate (POEGMA) and a hydrophobic part of camptothecin (CPT) prodrug and poly[2-(diisopropylamino)ethyl methacrylate] (PDPA), denoted as ß-CD-PDPA-POEGMA-PCPT (CCDO for short). The obtained CCDO could form stable unimolecular micelles, which could be efficiently internalized by cancer cells. To enhance the curative effect, the anticancer agent doxorubicin (DOX) could be encapsulated into the hydrophobic cavity of the CCDO by hydrophobic-hydrophobic interaction. In vitro drug release studies showed that the obtained CCDO/DOX micelles controlled the release of active CPT and DOX occurring in a reductive environment and at low pH. In vitro cytotoxicity results suggested that the anticancer efficacy of dual-responsive CCDO/DOX micelles was superior to that of CCDO micelles. In addition, in vivo results verified good blood compatibility of the unimolecular micelles. This integrated dual-responsive drug delivery system may solve the low drug loading and poor controlled release problems found in traditional polymer-based drug carriers, providing an innovative and promising route for cancer therapy.

[Study on adsorption of methylene blue by sulfonated polyethersulfone I. The preparation of sulfonated polyethersulfone and its adsorption of methylene blue in water].

The evaluation of the adsorption of methylene blue (MB) in water by the sulfonated polyethersulfone (SPES) adsorbent column was carried out in this study after the SPES was prepared by gassy SO3 method. The polyethersulfone (PES) adsorbent column was used as control. The results indicated that the adsorption of MB by adsorbent column of SPES was more efficient than that of PES. In addition, the effect of the flow rate or ionic intensity on the adsorption and desorption of MB in water by SPES adsorbent column were also investigated. The results showed that the removal rate in water by SPES adsorbent column was larger than that in saline. However, the desorption experiment revealed that the desorption amount of the SPES adsorbent column in saline was larger than that in water.

[Study on adsorption of methylene blue by sulfonated polyethersulfone II. The adsorption of methylene blue by sulfonated polyethersulfone in plasma].

The evaluation of the adsorption of methylene blue (MB) in plasma by sulfonated polyethersulfone (SPES) adsorbent column was carried out in this study. The results indicated the adsorption of MB by SPES adsorbent column was more efficient than that by polyethersulfone (PES). In addition, the changes of the concentration of BSA solution passing through adsorbent column along with the time and the biochemical indices of plasma before and after adsorption treatment were also investigated. The results showed that the adsorption amount of BSA by PES adsorbent column was larger than that by SPES, and the biochemical parameters such as total protein, albumin, glucose, triglyceride and total cholesterol in plasma varied slightly before and after passing through the column, which were still within the clinical indices.

[Grafting and characterization of poly (ethylene glycol) on polysulfone sheets].

Grafting of poly (ethylene glycol) (PEG) on the surface of polysulfone (PSF) sheets by simultaneous or sequential UV irradiation with 4-azidobenzoic acid as the photocoupler was carried out. Water contact angle measurements showed that there was a great improvement of hydrophilicity on the grafted surface. X-ray photoelectron spectroscopy suggested that the area covered by PEG be 77.3% and 41.9% respectively after grafting by simultaneous and sequential pathways. With atomic force microscope (AFM), obvious difference in the shape and the phase mode was observed between surfaces of PEG-g-PSF sheets made by these two pathways. Evidences implied that simultaneous pathway would produce a branched PEG layer on the surface, while sequential pathway was coupled with a "pan-cake" PEG layer on it. This study provides the foundation for further advancement in tethering brush-like PEG on PSF hollow fiber membranes.

Au-F127 strawberry-like nanospheres as an electrochemical interface for sensitive detection of carcinoembryonic antigen in real sample.

Nanomaterial-based signal-amplification strategies hold a great promise in realizing sensitive biological detection. A simple label-free electrochemical immunosensor for sensitive detection of carcinoembryonic antigen (CEA) was developed by immobilizing anti-CEA antibodies onto the Au-F127 strawberry-like nanospheres modified glassy carbon electrode (Au-F127/GCE). The Au-F127 strawberry-like nanospheres offered a large surface and multifunctional substrate for the effective immobilization of anti-CEA and the existence of Au could accelerate electron transfer and make the electrochemical signal amplified. The Au-F127 nanocomposites and anti-CEA were characterized by transmission electron microscopy (TEM), polycrystalline electron diffraction ring pattern, ultra-violet visible (UV-vis) spectra and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were employed to verify the stepwise assembly of the immunosensor and evaluated the analytical performance of the fabricated immunosensor, respectively. The immunosensor showed a wide liner response range between 0.01 and 80 ng mL(-1) with a low detection limit of 0.24 pg mL(-1) at a signal-to-noise (S/N) ratio of 3. Additionally, the proposed method was successfully applied to determine CEA in human serum samples with satisfactory results.

Functional supramolecular polymers for biomedical applications.

As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology.

Microfluidic devices with permeable polymer barriers for capture and transport of biomolecules and cells.

We report a method for fabricating permeable polymer microstructure barriers in polydimethylsiloxane (PDMS) microfluidic devices and the use of the devices to capture and transport DNA and cells. The polymer microstructure in a desired location in a fluidic channel is formed in situ by the polymerization of acrylamide and polyethylene diacrylate cross-linker (PEG-DA) monomer in a solution which is trapped in the location using a pair of PDMS valves. The porous polymer microstructure provides a mechanical barrier to convective fluid flow in the channel or between two microfluidic chambers while it still conducts ions or small charged species under an electric field, allowing for the rapid capture and transport of biomolecules and cells by electrophoresis. We have demonstrated the application of the devices for the rapid capture and efficient release of bacteriophage λ genomic DNA, solution exchange and for the transport and capture of HeLa cells. Our devices will enable the multi-step processing of biomolecules and cells or individual cells within a single microfluidic chamber.