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1.
Environ Pollut ; 319: 121017, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36610654

RESUMO

Microplastics and endocrine disruptors (EDs) are contaminants of emerging concerns and ubiquitously present in aquatic ecosystems, establishing interactions that still are the subject of investigation due to their implications in the cotransport of pollutants. Then, we conducted mechanistic studies based on state-of-art computational chemistry methods to quantitatively understand the interaction mechanisms whereby polystyrene micro or nanoplastics (PS-MPs) interact with representative classes of EDs in water (Ethynylestradiol, Estradiol, and Bisphenol A). The results showed that PS-MPs increase their charge distribution when forming microparticles in water, giving a permanent dipole that explains their increasing solubility in aqueous conditions. In agreement with experimental assessments, the PS-MPs favorably adsorb EDs with adsorption energies larger than 15 kcal/mol, even with comparable stability to nanostructured materials for adsorption, removal, and/or analysis of pollutants. The adsorption occurs via physisorption without covalent binding, bond breaking, or structural preparation energies, where the molecular structure of EDs can favor inner or outer surface adsorption depending on the molecular structure of the adsorbates. A balanced contribution of dispersion and electrostatic stabilizing effects determines the interaction mechanisms, accounting for a whole contribution of 88-90%. The electrostatic contribution emerges from the favorable alignment of the PS-MPs and EDs dipoles upon interaction due to the mild charge transfer between them in solution. In contrast, the dispersion contribution emerges from electron-electron interactions due to the permanent dipoles in adsorbates and adsorbents. Furthermore, thermochemical analyses clarify the role of temperature and pressure effects on the relative adsorption stability among EDs in aquatic environments. Therefore, modeling the adsorption process contributes to new knowledge on the sorption properties of PS-MPs, providing a mechanistic basis to understand the cotransport of pollutants in water environments and their impacts on environmental pollution.


Assuntos
Disruptores Endócrinos , Poluentes Ambientais , Poluentes Químicos da Água , Microplásticos/química , Poliestirenos/análise , Plásticos/química , Disruptores Endócrinos/análise , Água , Adsorção , Ecossistema , Poluentes Químicos da Água/análise , Poluentes Ambientais/análise
2.
PLoS One ; 18(1): e0280074, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36608027

RESUMO

Membrane proteins of Mycobacterium tuberculosis (Mtb) can be targeted for the development of therapeutic and prophylactic interventions against tuberculosis. We have utilized the unique membrane-solubilising properties of the styrene maleic acid copolymer (SMA) to prepare and characterise 'styrene maleic acid lipid particles' from the native membrane of Mtb (MtM-SMALPs). When resolved by SDS-PAGE and visualised with coomassie blue, the molecular weights of Mtb membrane (MtM) proteins solubilised by SMA were mostly in the range of 40-70 kDa. When visualised by transmission electron microscopy, MtM-SMALPs appeared as nanoparticles of discrete shapes and sizes. The discoid nanoparticles exhibited a range of diameters of ~10-90 nm, with largest portion (~61%) ranging from 20-40 nm. MtM proteins of a molecular weight-range overlapping with that of MtM-SMALPs were also amenable to chemical cross-linking, revealing protein complex formation. Characterisation using monoclonal antibodies against seven MtM-associated antigens confirmed the incorporation of the inner membrane protein PRA, membrane-associated proteins PstS1, LpqH and Ag85, and the lipoglycan LAM into MtM-SMALPs. Conversely, the peripheral membrane proteins Acr and PspA were nearly completely excluded. Furthermore, although MtM showed an abundance of Con A-binding glycoproteins, MtM-SMALPs appeared devoid of these species. Immune responses of healthcare workers harbouring 'latent TB infection' provided additional insights. While MtM-SMALPs and MtM induced comparable levels of the cytokine IFN-γ, only MtM-SMALPs could induce the production of TNF-α. Antibodies present in the donor sera showed significantly higher binding to MtM than to MtM-SMALPs. These results have implications for the development of MtM-based immunoprophylaxis against tuberculosis.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Humanos , Estireno/química , Membrana Celular/química , Poliestirenos/química , Maleatos/análise , Maleatos/química , Proteínas de Membrana/química , Tuberculose/prevenção & controle , Lipídeos/química , Bicamadas Lipídicas/química
3.
Sci Rep ; 13(1): 1321, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36693888

RESUMO

Ratiometric green-red fluorescent nanosensors for fluorometrically monitoring pH in the acidic range were designed from 80 nm-sized polystyrene (PS) and silica (SiO2) nanoparticles (NPs), red emissive reference dyes, and a green emissive naphthalimide pH probe, analytically and spectroscopically characterized, and compared regarding their sensing performance in aqueous dispersion and in cellular uptake studies. Preparation of these optical probes, which are excitable by 405 nm laser or LED light sources, involved the encapsulation of the pH-inert red-fluorescent dye Nile Red (NR) in the core of self-made carboxylated PSNPs by a simple swelling procedure and the fabrication of rhodamine B (RhB)-stained SiO2-NPs from a silane derivative of pH-insensitive RhB. Subsequently, the custom-made naphthalimide pH probe, that utilizes a protonation-controlled photoinduced electron transfer process, was covalently attached to the carboxylic acid groups at the surface of both types of NPs. Fluorescence microscopy studies with the molecular and nanoscale optical probes and A549 lung cancer cells confirmed the cellular uptake of all probes and their penetration into acidic cell compartments, i.e., the lysosomes, indicated by the switching ON of the green naphthalimide fluorescence. This underlines their suitability for intracellular pH sensing, with the SiO2-based nanosensor revealing the best performance regarding uptake speed and stability.


Assuntos
Nanopartículas , Dióxido de Silício , Dióxido de Silício/química , Poliestirenos , Naftalimidas , Corantes Fluorescentes/química , Nanopartículas/química , Concentração de Íons de Hidrogênio
4.
Anal Chim Acta ; 1239: 340724, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36628724

RESUMO

This study developed a flexible and wearable paper-based chemoresistive sensor (FWPCS) by modifying a SWCNT-PdNP-polystyrene microsphere (SPPM) composite (SPPM/FWPCS) for the low-cost and online determination of fruit ripeness and corruption. A new method for the batch and low-cost fabrication of SPPM/FWPCSs based on laser direct writing was proposed. The sensing mechanism of FWPCS relies on the electron depletion layer in the sensing composite created by the Schottky barriers among SWCNTs, PdNPs, and the adsorbed oxygen, along with the construction of O2-. When the SPPM sensing film is exposed to ethylene, trapped electrons are released into the conduction band through oxidation and cleavage of ethylene, causing a decrease in resistance. The properties and morphology of the synthesized SPPM composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Additionally, the key parameters for the fabrication of SPPMs/FWPCS related to the sensing performance were optimized. The concentration of C2H4 can be detected down to 100 ppb using the SPPMs/FWPCS at 25 °C. Finally, the real-time determination of banana ripeness and corruption verified the feasibility of the sensor, indicating that the SPPMs/FWPCS has prospects in monitoring fruit ripeness and corruption during storage and transportation.


Assuntos
Poliestirenos , Dispositivos Eletrônicos Vestíveis , Microesferas , Frutas , Oxigênio , Etilenos
5.
Part Fibre Toxicol ; 20(1): 3, 2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36647127

RESUMO

Nano- and microplastic particles (NMP) are strong environmental contaminants affecting marine ecosystems and human health. The negligible use of biodegradable plastics and the lack of knowledge about plastic uptake, accumulation, and functional consequences led us to investigate the short- and long-term effects in freshly isolated skin cells from mice. Using fluorescent NMP of several sizes (200 nm to 6 µm), efficient cellular uptake was observed, causing, however, only minor acute toxicity as metabolic activity and apoptosis data suggested, albeit changes in intracellular reactive species and thiol levels were observed. The internalized NMP induced an altered expression of various targets of the nuclear factor-2-related transcription factor 2 pathway and were accompanied by changed antioxidant and oxidative stress signaling responses, as suggested by altered heme oxygenase 1 and glutathione peroxide 2 levels. A highly increased beta-catenin expression under acute but not chronic NMP exposure was concomitant with a strong translocation from membrane to the nucleus and subsequent transcription activation of Wnt signaling target genes after both single-dose and chronic long-term NMP exposure. Moreover, fibroblast-to-myofibroblast transdifferentiation accompanied by an increase of α smooth muscle actin and collagen expression was observed. Together with several NMP-induced changes in junctional and adherence protein expression, our study for the first time elucidates the acute and chronic effects of NMP of different sizes in primary skin cells' signaling and functional biology, contributing to a better understanding of nano- and microplastic to health risks in higher vertebrates.


Assuntos
Microplásticos , Poliestirenos , Via de Sinalização Wnt , Animais , Camundongos , beta Catenina/genética , beta Catenina/metabolismo , beta Catenina/farmacologia , Ecossistema , Microplásticos/toxicidade , Estresse Oxidativo , Poliestirenos/toxicidade
6.
Adv Skin Wound Care ; 36(2): 93-97, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36662042

RESUMO

OBJECTIVE: To compare the effectiveness of four positioning aids in able-bodied participants and those with tetraplegia, to determine (1) if devices differed with regard to pressure reduction and (2) if results differed for able-bodied participants versus those with tetraplegia. METHODS: Forty volunteers (20 able-bodied and 20 with tetraplegia) participated. The variable of interest was reduction in mean pressure in the sacral region, measured in mm Hg. Testing was conducted in a hospital bed using a tissue-interface pressure-mapping system. Four bed positioning devices were examined in use at both 0° and 30° head-of-bed elevations: standard hospital pillows, fluidized positioners, foam wedge positioners, and polystyrene bead wedge positioners. RESULTS: No between-group differences were found for participant type (able-bodied vs tetraplegic). However, the positioning devices tested did differ significantly in pressure reduction. Foam wedge positioners, polystyrene bead wedge positioners, and fluidized positioners all resulted in greater reduction in pressure over an area inclusive of the sacrum, ischia, and buttocks when compared with standard hospital pillows, with foam wedges performing best. CONCLUSIONS: Better pressure reduction over the sacrum, buttocks, and ischia can be achieved when using devices specifically designed for patient positioning in bed as opposed to using standard hospital pillows. Data were not significantly different between able-bodied participants and participants with tetraplegia. Thus, pressure-mapping data examining the efficacy of bed-positioning devices using convenience sampling of able-bodied individuals can likely be generalized to apply to a population with tetraplegia as well.


Assuntos
Poliestirenos , Quadriplegia , Humanos , Pressão , Roupas de Cama, Mesa e Banho , Região Sacrococcígea
7.
Biomolecules ; 13(1)2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36671525

RESUMO

Plastic is a polymer extremely resistant to degradation that can remain for up to hundreds or thousands of years, leading to the accumulation of massive amounts of plastic waste throughout the planet's ecosystems. Due to exposure to various environmental factors, plastic breaks down into smaller particles named microplastics (1-5000 µm) and nanoplastics (<1 µm). Microplastics (MPs) are ubiquitous pollutants but, still, little is known about their effects on human and animal health. Herein, our aim is to investigate cytotoxicity, oxidative stress, inflammation and correlated gene modulation following exposure to polystyrene microplastics (PS-MPs) in HRT-18 and CMT-93 epithelial cell lines. After 6, 24 and 48 h PS-MPs treatment, cell viability (MTT) and oxidative stress (SOD) assays were performed; subsequently, expression changes and cytokines release were investigated by Real-Time PCR and Magnetic-beads panel Multiplex Assay, respectively. For each exposure time, a significantly increased cytotoxicity was observed in both cell lines, whereas SOD activity increased only in CMT-93 cells. Furthermore, Magnetic-beads Multiplex Assay revealed an increased release of IL-8 in HRT-18 cells' medium, also confirmed by gene expression analysis. Results obtained suggest the presence of a pro-inflammatory pattern induced by PS-MPs treatment that could be related to the observed increase in cytotoxicity.


Assuntos
Antineoplásicos , Poluentes Químicos da Água , Humanos , Animais , Camundongos , Microplásticos/toxicidade , Poliestirenos/toxicidade , Plásticos , Ecossistema , Linhagem Celular , Poluentes Químicos da Água/toxicidade
8.
Int J Mol Sci ; 24(2)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36674627

RESUMO

Here, to develop new topical antibacterial formulations to treat staphylococcal infections, two pyrazoles (3c and 4b) previously reported as antibacterial agents, especially against staphylococci, were formulated as hydrogels (R1-HG-3c and R1HG-4b) using a cationic polystyrene-based resin (R1) and here synthetized and characterized as gelling agents. Thanks to the high hydrophilicity, high-level porosity, and excellent swelling capabilities of R1, R1HG-3c and R1HG-4b were achieved with an equilibrium degree of swelling (EDS) of 765% (R1HG-3c) and 675% (R1HG-4b) and equilibrium water content (EWC) of 88% and 87%, respectively. The chemical structure of soaked and dried gels was investigated by PCA-assisted attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy, while their morphology was investigated by optical microscopy. Weight loss studies were carried out with R1HG-3c and R1HG-4b to investigate their water release profiles and the related kinetics, while their stability was evaluated over time both by monitoring their inversion properties to detect possible impairments of the 3D network and by PCA-assisted ATR-FTIR spectroscopy to detect possible structural changes. The flow and dynamic rheological characterization of the gels was assessed by determining their viscosity vs. shear rate, applying the Cross rheological equation to achieve the curves of shear stress vs. shear rate, and carrying out amplitude and frequency sweep experiments. Finally, their content in NH3+ groups was determined by potentiometric titrations. Due to their favorable physicochemical characteristic and the antibacterial effects of 3c and 4b possibly improved by the cationic R1, the pyrazole-enriched gels reported here could represent new weapons to treat severe skin and wound infections sustained by MDR bacteria of staphylococcal species.


Assuntos
Hidrogéis , Poliestirenos , Hidrogéis/química , Antibacterianos/farmacologia , Antibacterianos/química , Excipientes , Composição de Medicamentos , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Environ Pollut ; 319: 120987, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36592883

RESUMO

The contamination of the aquatic environment with microplastics has become a global environmental concern. Microplastic particles can be shredded to form smaller nanoplastics, and knowledge on their impacts on phytoplankton, especially freshwater microalgae, is still limited. To investigate this issue, the microalga Scenedesmus quadricauda was exposed to polystyrene nanoplastics (PS-NPs) of five concentrations (10, 25, 50, 100, and 200 mg/L). The growth; the contents of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD); the chlorophyll content; and concentrations of soluble protein and soluble polysaccharide were accordingly measured. The results showed that the microalgal density increased with the increase of the polystyrene nanoplastic concentrations, and the physiological features of alga were enhanced after the stimulation of nanoplastics. Furthermore, a high concentration (200 mg/L) of nanoplastics increased the contents of chlorophyll, soluble protein, and polysaccharide (P < 0.05). The antioxidant enzyme activities of Scenedesmus quadricauda were significantly activated by nanoplastics. Lastly, we propose three possible algal recovery mechanisms in response to nanoplastics in which Scenedesmus quadricauda was tolerant with PS-NPs by cell wall thickening, internalization, and aggregation. The results of this study contribute to understanding of the ecological risks of nanoplastics on freshwater microalgae.


Assuntos
Microalgas , Scenedesmus , Poluentes Químicos da Água , Poliestirenos/química , Antioxidantes/metabolismo , Microplásticos/toxicidade , Microplásticos/metabolismo , Plásticos/metabolismo , Microalgas/metabolismo , Clorofila/metabolismo , Scenedesmus/metabolismo , Poluentes Químicos da Água/metabolismo
10.
Biotechniques ; 74(1): 45-50, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36621959

RESUMO

Amberlite has been shown to be an appropriate material for the adsorption of organic contaminants from aqueous solutions. In addition, Amberlite XAD-2 has been successfully used, as an alternative to Bio-Beads, to remove Triton X-100 from protein solutions, such as from samples of solubilized membrane proteins. However, Amberlite has not been tested as an adsorbent when a mixture of detergents is necessary to solubilize and refold a target protein. Here the authors show that Amberlite XAD-4 can be appropriately used to aid the purification process of proteins solubilized from inclusion bodies with the ternary detergent system consisting of Sarkosyl, Triton X-100 and CHAPS.


Assuntos
Poliestirenos , Octoxinol
11.
Environ Pollut ; 319: 121015, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36610653

RESUMO

Micro/nano-plastics (M/NPs) are emerging contaminants in aquatic environment, however, little knowledge regarding the adverse effects of functionalized NPs has been documented so far. This study investigated the accumulation of different polystyrene nanoplastics (PS-NPs, i.e., plain PS, carboxyl-functional PS-COOH and amino-functional PS-NH2) at two particle sizes of 100 nm and 200 nm, and evaluated the impacts on oxidative stress, energy metabolism and mitochondrial pathway responses in intestine and respiratory tree of Apostichopus japonicus during the 20-d exposure experiment. The results showed that there were significant interactions of particle size and nanoplastic type on the accumulation of different PS-NPs. Exposure to NPs significantly increased the production of malondialdehyde, glutathione and reactive oxygen species, as well as the activities of antioxidant enzymes including glutathione reductase, superoxide dismutase and catalase, resulting in various degrees of oxidative damage in sea cucumber. The significant decrease in adenosine triphosphate content and increases in alkaline phosphatase and lactate dehydrogenase activities suggested that NPs impaired energy metabolism and modified their energy allocation. After 20-d exposure, the complex I, II and III activities in mitochondrial respiratory chain were significantly inhibited. Meanwhile, the Bax and Caspase-3 gene expression were significantly up-regulated, and Bacl-2 was down-regulated, indicating the toxicity on mitochondrial pathway of A. japonicus. The calculated IBR values elucidated the greater detriment to mitochondrial pathway than oxidative stress and energy metabolism. For 100 nm particle size, plain PS has stronger influence on all the biomarkers compared to PS-COOH/NH2, however, the opposite trends were observed in 200 nm PS-NPs. Furthermore, 100 nm PS-NPs were recognized to be more hazardous to sea cucumber than 200 nm microbeads. These findings provide new insights for understanding the differentiated toxic effects of functionalized NPs in marine invertebrates.


Assuntos
Nanopartículas , Pepinos-do-Mar , Stichopus , Poluentes Químicos da Água , Animais , Bioacumulação , Metabolismo Energético , Microplásticos/toxicidade , Nanopartículas/toxicidade , Estresse Oxidativo , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Mitocôndrias/metabolismo
12.
Anal Methods ; 15(4): 472-481, 2023 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36602291

RESUMO

A novel analytical proposal based on nanofiber-packed solid-phase extraction coupled with high performance liquid chromatography-fluorescence detector (HPLC-FLD) has been successfully developed for determining aflatoxin B1 (AFB1) in foods. Four types of nanofibers, including polystyrene (PS) nanofibers, polypyrrole (PPY) nanofibers, polystyrene-acrylic resin (PS-AR) nanofibers, and polystyrene-polyvinyl pyrrolidone (PS-PVP) nanofibers, were fabricated by electrospinning and utilized to prepare a home-made extraction device. In this study, the factors of different fibers, namely, fiber dosage, pH of extraction solution, type of salt ion, concentration of salt ion, and volume of the eluent were optimized. Under optimized conditions, the method showed good linearity in the range of 0.1-40 ng mL-1 with a correlation coefficient greater than 0.999 and good inter-day accuracy (90.8-112.7% recovery) and precision (1.8-3.6% intra-day RSDs, 2.6% inter-day RSD), and the limit of detection (LOD) was 0.05 ng mL-1. Due to its cost-effective, time-saving, environmentally friendly, and simple performance, it has the potential to be utilized to determine aflatoxins in complicated matrices.


Assuntos
Aflatoxina B1 , Nanofibras , Cromatografia Líquida de Alta Pressão/métodos , Polímeros , Poliestirenos , Pirróis , Extração em Fase Sólida/métodos
13.
Sci Total Environ ; 865: 161271, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36587662

RESUMO

Nanoplastics are the persistent pollutants in a variety of environments, representing a potential threat to human health. Notably, plastic particles have been detected in sample of human bloodstream. It is thus significant to investigate the effects of nanoplastics on the cardiovascular system owing to its ease transfer through the bloodstream to other organs. However, few studies have been performed to evaluate the cardiovascular toxicity of nanoplastics. Herein, we pursued to investigate the adverse cardiovascular impacts of polystyrene (PS), PS-NH2 and PS-COOH nanoplastics on mice. Experimental results demonstrated that the exposure to these nanoplastics could result in structural damage of vascular endothelial cells and inflammatory response. Moreover, it was found out that the dysfunctions of coagulation and prethrombotic state were caused by nanoplastics, which could be ascribed to the activation of JAK1/STAT3/TF signaling pathway. In summary, results clearly indicated that nanoplastic exposure lead to vascular toxicity to mice, which serves as a basis for future studies about the potential physiological threat of nanoplastics to humans.


Assuntos
Transtornos da Coagulação Sanguínea , Nanopartículas , Poluentes Químicos da Água , Animais , Humanos , Camundongos , Microplásticos , Células Endoteliais/química , Células Endoteliais/metabolismo , Poliestirenos/metabolismo , Plásticos/toxicidade , Nanopartículas/toxicidade , Poluentes Químicos da Água/toxicidade
14.
Sci Total Environ ; 865: 161248, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36587669

RESUMO

Marine nanoplastics (NPs) have attracted increasing global attentions because of their detrimental effects on marine environments. A co-existing major environmental concern is ocean acidification (OA). However, the effects of differentially charged NPs on marine organisms under OA conditions are poorly understood. We therefore investigated the effects of OA on the embryotoxicity of both positively and negatively charged polystyrene (PS) NPs to marine medaka (Oryzias melastigma). Positively charged PS-NH2 exhibited slighter aggregation under normal conditions and more aggregation under OA conditions than negatively charged PS-COOH. According to the integrated biomarker approach, OA reversed the toxicity of positively and negatively charged NPs towards embryos. Importantly, at environmental relevant concentrations, both types of PS-NPs could enter the embryos through chorionic pores and then transfer to the larvae. OA reversed the internalization of PS-NH2 and PS-COOH in O. melastigma. Overall, the reversed toxicity of PS-NH2 and PS-COOH associated with OA could be caused by the reversed bioavailability of NPs to O. melastigma, which was attributed to altered aggregation of the NPs in acidified seawater. This finding demonstrates the charge-dependent toxicity of NPs to marine fish and provides new insights into the potential hazard of NPs to marine environments under OA conditions that could be encountered in the near future.


Assuntos
Nanopartículas , Oryzias , Poluentes Químicos da Água , Animais , Poliestirenos/toxicidade , Água do Mar , Microplásticos , Concentração de Íons de Hidrogênio , Acidificação dos Oceanos , Poluentes Químicos da Água/toxicidade , Nanopartículas/toxicidade
15.
Sci Total Environ ; 865: 161240, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36587672

RESUMO

Although evidence suggests the ubiquity of meso- and microplastics (MMPs) in mangrove forests, our knowledge of their bioavailability and risk on mangrove leaves is scarce. Here, we investigated MMP contamination concerning submerged mangrove leaves and herbivorous snails that mainly feed on them from the four mangrove forests located in Beibu Gulf, Guangxi Province, China. Results showed that the MMP abundance on the mangrove leaves ranged from 0.01 ± 0.00 to 0.42 ± 0.15 items cm-2, while it ranged from 0.33 ± 0.21 to 6.20 ± 2.91 items individual-1 in the snails. There were significant positive correlations between snails and leaves regarding the abundance of total MMPs and the proportions of MMPs with the same characteristics. Expanded polystyrene (EPS) that mainly derived from aquaculture rafts, accounted for a major component both on the leaves and in the snails in Shi Jiao (SJ). Both the detection frequency and percentage of larger EPS (2.00-17.50 mm) on the leaves in SJ were higher than other sites. Meanwhile, the detection frequency, abundance and percentage of larger EPS on the leaves had significant positive correlations with those of micro-EPS in the snails. These findings suggested that mangrove leaves may represent a viable pathway for MMPs to enter the herbivorous snails. Larger EPS with higher frequency of occurrence on mangrove leaves were more likely to be encountered and ingested by snail considering its opportunistic feeding behavior. In addition, 11 sensitive genes involved in the processes of metabolism, intestinal mucosal immune systems, and cellular transduction in the snails were significantly suppressed by MMP exposure, which may be potentially used as early biomarkers to indicate the biological effects of MMPs under realistic environmental conditions. Overall, this study provides novel insights into the fate, sources, and biological effects of MMPs on mangrove leaves.


Assuntos
Microplásticos , Plásticos , Monitoramento Ambiental/métodos , China , Áreas Alagadas , Poliestirenos/análise
16.
J Hazard Mater ; 446: 130617, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36623344

RESUMO

Microplastics (MPs) are emerging pollutants which exist in various environments and pose a potential threat to human health. However, the effect of MP on respiratory pathogens-infected organisms is unknown. In order to explore the effect of MP on respiratory pathogen infection, we studied the effect of polystyrene microplastics (PS) on influenza A virus (IAV)-infected A549 cells. Western blot, qPCR, and viral plaque assay demonstrated that PS could promote IAV infection. Further study by bioluminescence imaging showed that a large number of IAV could be enriched on PS and entered cells through endocytosis. Meanwhile, the expression of IFITM3 in cells was significantly reduced. In addition, our results showed that PS down-regulated IRF3 and its active form P-IRF3 by down-regulating RIG-I and inhibiting TBK1 phosphorylation activation, which then significantly reduced IFN-ß expression and affected the cellular innate antiviral immune system. Taken together, our results indicate the potential threat of MPs to respiratory diseases caused by IAV and provide new insights into human health protection.


Assuntos
Vírus da Influenza A , Influenza Humana , Humanos , Microplásticos/toxicidade , Plásticos , Poliestirenos/toxicidade , Vírus da Influenza A/fisiologia , Proteínas de Membrana , Proteínas de Ligação a RNA
17.
J Hazard Mater ; 446: 130713, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36630882

RESUMO

In this work, the effects of extracellular polymeric substances (EPS) on the aggregation and biological responses of different micro(nano)plastics (MNPs, <1000 µm) were investigated. EPS increased the colloidal stability of PS MPs in NaCl or CaCl2. For the three PS NPs (PS-NH2, PS-COOH, and PS-naked), EPS also enhanced their colloidal stabilities in the presence of NaCl. However, the effect of CaCl2 on the colloidal stabilities of PS NPs in the presence of EPS depended on their surface functional groups. In CaCl2, both Derjaguin-Landau-Verwey-Overbeek theory and molecular bridging explained the interaction between MNPs (both NPs and MPs) and EPS. Laser Direct Infrared and scanning electron microscope imaging showed that opalescent EPS corona formed on PS MPs via intermolecular-bridging by Ca2+, and the critical coagulation concentrations (70 mM in NaCl, 1.5 mM in CaCl2) in EPS were much lower than that for PS NPs (1000 mM for NaCl; 65 mM for CaCl2). PS-NH2 NPs showed the highest increase in the growth of bacteria (Bacillus subtilis), followed by PS MPs and PS-naked NPs, while PS-COOH NPs had no significant effect. Biological response of PS NPs was unaffected by EPS, while EPS further enhanced the positive effects of PS MPs on bacterial growth.


Assuntos
Nanopartículas , Plásticos , Matriz Extracelular de Substâncias Poliméricas , Cloreto de Sódio/farmacologia , Cloreto de Cálcio/farmacologia , Poliestirenos
18.
Anal Chem ; 95(4): 2561-2569, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36656064

RESUMO

Here, we achieve the separation and enrichment of Escherichia coli clusters from its singlets in a viscoelastic microfluidic device. E. coli, an important prokaryotic model organism and a widely used microbial factory, can aggregate in clusters, leading to biofilm development that can be detrimental to human health and industrial processes. The ability to obtain high-purity populations of E. coli clusters is of significance for biological, biomedical, and industrial applications. In this study, polystyrene particles of two different sizes, 1 and 4.8 µm, are used to mimic E. coli singlets and clusters, respectively. Experimental results show that particles migrate toward the channel center in a size-dependent manner, due to the combined effects of inertial and elastic forces; 4.8 and 1 µm particles are found to have lateral equilibrium positions closer to the channel centerline and sidewalls, respectively. The size-dependent separation performance of the microdevice is demonstrated to be affected by three main factors: channel length, the ratio of sheath to sample flow rate, and poly(ethylene oxide) (PEO) concentration. Further, the separation of E. coli singlets and clusters is achieved at the outlets, and the separation efficiency is evaluated in terms of purity and enrichment factor.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Humanos , Microfluídica/métodos , Escherichia coli , Polietilenoglicóis , Poliestirenos
20.
Proc Natl Acad Sci U S A ; 120(4): e2213441120, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36649431

RESUMO

A twin boundary (TB) is a common low energy planar defect in crystals including those with the atomic diamond structure (C, Si, Ge, etc.). We study twins in a self-assembled soft matter block copolymer (BCP) supramolecular crystal having the double diamond (DD) structure, consisting of two translationally shifted, interpenetrating diamond networks of the minority polydimethyl siloxane block embedded in a polystyrene block matrix. The coherent, low energy, mirror-symmetric double tubular network twin has one minority block network with its nodes offset from the (222) TB plane, while nodes of the second network lie in the plane of the boundary. The offset network, although at a scale about a factor of 103 larger, has precisely the same geometry and symmetry as a (111) twin in atomic single diamond where the tetrahedral units spanning the TB retain nearly the same strut (bond) lengths and strut (bond) angles as in the normal unit cell. In DD, the second network undergoes a dramatic restructuring-the tetrahedral nodes transform into two new types of mirror-symmetric nodes (pentahedral and trihedral) which alternate and link to form a hexagonal mesh in the plane of the TB. The collective reorganization of the supramolecular packing highlights the hierarchical structure of ordered BCP phases and emphasizes the remarkable malleability of soft matter.


Assuntos
Bandagens , Diamante , Grupos Minoritários , Polímeros , Poliestirenos
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