Selective on-site detection and quantification of polystyrene microplastics in water using fluorescence-tagged peptides and electrochemical impedance spectroscopy.

In this study, we developed a method for the on-site selective detection and quantification of microplastics in various water matrices using fluorescence-tagged peptides combined with electrochemical impedance spectroscopy (EIS). Among the types of plastics found in seawater, polystyrene (PS) microplastics were selected. Fluorometry, scanning electron microscopy (SEM), and Raman spectroscopy were used to verify the specific interaction of these peptides with PS spherical particles of different sizes (ranging from 0.1 to 250 µm). Principal component analysis (PCA) was employed to determine the effects of temperature (25-65 °C), incubation time (5 and 10 min), and particle size on plastic-peptide bonding efficiency, based on fluorescence intensity. For each water type (pure, tap, NaCl (0.5 M), and seawater), EIS plots (Nyquist and Bode) were generated. Significant factors affecting the EIS response, including particle size, shape, and material, were analyzed by measuring electrical parameters for different microplastic concentrations (50 ppb to 20 ppm). The EIS parameters changed with increasing plastic concentration, determining a limit of detection (LOD) of 50 ppb (ng/mL) for pure and tap water and 400 ppb for saline water, as the lowest concentration producing a significant change in EIS parameters compared to the baseline. The sensor proved highly effective for detecting microplastics in low ionic strength environments such as pure and tap water. However, in high ionic strength environments like saline and seawater, the detection capability diminished, likely due to the masking effect of ions on the EIS response.

A sustainable approach towards extraction of diosgenin from fenugreek seeds using polystyrene/divinyl benzene resin.

Diosgenin, a bioactive molecule; is one of the deeply explored saponin with a wide spectrum of benefits against various ailments. The extraction and yield enhancement of diosgenin from a wide range of naturally occurring medicinal products has always been a challenging task for its commercial usage. The current research work envisages the use of a novel resin to maximize the yield of diosgenin. The extracted diosgenin was characterized using modern techniques. The current method qualifies for the extraction of diosgenin at a large scale making it a commercially viable technique.

Preferred Lung Accumulation of Polystyrene Nanoplastics with Negative Charges.

With the increasing presence of nanoplastics (NPs) in the human bloodstream, it is urgent to investigate their tissue accumulation and potential health risks. This study examines the effects of the size and surface charges of polystyrene (PS) NPs on lung accumulation. Using magnetic separation, we identified the protein corona composition on iron-core PS NPs, revealing the enrichment of vitronectin and fibrinogen. The corona promotes integrin αIIbß3 receptor-mediated uptake by lung endothelial cells, explaining that both the corona composition and protein structure determine preferred localization of negatively charged PS NPs in the lung. This study uncovers the role of protein corona in NP uptake and the way NPs enter the lung, emphasizing the need to consider interactions between nanoplastics with varying surface characteristics and biological molecules in the nanotoxicological field.

Eco-environmental responses of Eichhornia crassipes rhizobacteria community to co-stress of per(poly)fluoroalkyl substances and microplastics.

The stabilization of rhizobacteria communities plays a crucial role in sustaining healthy macrophyte growth. In light of increasing evidence of combined pollution from microplastics (MPs) and per- and polyfluoroalkyl substances (PFASs), Selecting typical floating macrophyte as a case, this study explored their impacts using hydroponic simulations and 16S rRNA high-throughput sequencing. A total of 31 phyla, 77 classes, 172 orders, 237 families, 332 genera, and 125 rhizobacteria species were identified. Proteobacteria (16.19% to 57.70%) was the dominant phylum, followed by Bacteroidota (12.34% to 44.48%) and Firmicutes (11.31% to 36.36%). In terms of α-diversity, polystyrene (PS) MPs and PFASs significantly impacted community abundance (ACE and PD-tree) rather than evenness (Shannon and Pielou) compared to the control. ßMNTD and ßNTI analyses revealed that PS MPs enhanced deterministic assembly processes driven by F-53B and GenX, while mitigating those induced by PFOA and PFOS. Contamination treatments narrowed the ecological niche breadths at both the phylum (5% (PS) to 49.91% (PS & PFOA)) and genus levels (8% (PS) to 63.96% (PS & PFOA)). Functionally, MPs and PFASs decreased the anaerobic capacity and ammonia nitrogen utilization of rhizosphere bacteria. This study enhances our understanding of the microecological responses of macrophyte-associated bacteria to combined MP and PFAS contamination and offers insights into ecological restoration strategies and mitigating associated environmental risks.

Changes in global methylation patterns of Mytilus galloprovincialis exposed to microplastics.

Microplastics (MPs) disturb the normal activity of aquatic organisms at different levels, causing physiological stress and altering feeding, growth, and reproduction. Alterations of epigenetic patterns due to exposure to MPs have scarcely been studied in invertebrates. In this study, Mytilus galloprovincialis mussels (N = 61) were intermittently exposed to different concentrations of pure polystyrene microbeads for three weeks. The concentrations used in this research were similar to those currently found in certain polluted environments (E1), as well as higher doses to which mussels could be further exposed (E2 and E3). After exposure period, the global methylation patterns were investigated using Amplified Fragment Length Polymorphism (AFLPs). Significantly lower methylation was found in exposed groups compared to the control group. The level of hypomethylation increased with the concentration of microbeads. Similar results were found from field samples inhabiting two sites differentially MPs-polluted. The implications of this discovery were analysed and discussed, noting the already known effects of MPs on metabolism and cell division. Further studies on this and other sentinel organisms are recommended to understand the response of the aquatic species to the currently increasing MPs pollution.

An integrated approach for plastic polymer degradation by the gut bacterial resident of superworm, Zophobas morio (Coleoptera:Tenebrionidae).

The potential of superworm to remove certain plastic polymers has recently been noted. In this study, aerobic bacterial strains were isolated from the gut of Zophobas morio larvae which were fed with polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) polymers. Strains P2 (Leminorella), P6 (Bacillus), P9 (Bacillus), and P5 (Citrobacter) were associated with the highest PS (2.7%), PP (1.3%), PET (1.1%), and PE (0.42%) weight loss after 28 days, respectively. Pretreatments including thermal treatment (80 °C for 10 days), weathering (4 months in the free environment), and nitric and sulfuric acids (1 N, 10 days) improved the degradation of PE (1.3%), PET (1.9%), PP (5.2%), and PS (8.3%) by the same strains, respectively. Further analyses on the PS degradation by Leminorella sp. P2 revealed acid pretreatment promoted the formation of the C = C, C = O, and O-H functional groups. Surface irregularities, as well as a 3.6-fold increase in surface roughness, were observed in the PS film subjected to biodegradation. The contact angle dropped from 98.4° to 42.2° following the biodegradation. Bacterial depolymerization was confirmed by the 8.7% and 3.4% reduction of Mn and Mw and the change in polydispersity from 1.65 to 1.75. The results suggest that Zophobas morio microbiota in combination with abiotic pretreatment can be considered for plastic waste management.

Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles.

Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles.Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates.Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells.

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Distinctive toxic repercussions of polystyrene nano plastic towards aquatic non target species Nitrobacter vulgaris, Scenedesmus sp and Daphnia magna.

The widespread application of plastics and its eventual degradation to micro-sized or nano-sized plastics has led to several environmental concerns. Moreover, nanoplastics can easily cascade through the food chain accumulating in the aquatic organisms. Thus, our study focussed on investigating the hazardous impact of nano-sized plastics on aquatic species including Nitrobacter vulgaris, Scenedesmus sp, and Daphnia magna. Various concentrations of polystyrene nanoplastics ranging from 0.01 mg/L to 100 mg/L were tested against Nitrobacter vulgaris, Scenedesmus sp, and Daphnia magna. The minimum inhibitory concentration of polystyrene nanoplastics in Nitrobacter vulgaris was found to be 25 mg/L, and in Daphnia magna, the median lethal concentration 50 was observed to be 64.02 mg/L. Exposure of Scenedesmus sp with increasing nanoplastic concentrations showed a significant decrease in total protein (p < 0.001), and chlorophyll content (p < 0.01), whereas the lipid peroxidation increased (p < 0.001) significantly. Similarly, Nitrobacter vulgaris and Daphnia magna showed a significant decrease in catalase activity (p < 0.001) and an increase in lipid peroxidation levels (p < 0.01). Concomitant with lipid peroxidation results, decreased superoxide dismutase levels (p < 0.01) and protein concentrations (p < 0.01) were observed in Daphnia magna. Besides, the increasing concentration of polystyrene nanoplastics displayed an elevated mortality rate in Scenedesmus sp (p < 0.001) and Nitrobacter vulgaris (p < 0.01). Further, scanning electron microscopy analysis substantiated the morphological alterations in Nitrobacter vulgaris and Scenedesmus sp on exposure to polystyrene nanoplastics.

Impact of dissolved organic matter characteristics and inorganic species on the stability and removal by coagulation of nanoplastics in aqueous media.

The aggregation of rough, raspberry-type polystyrene nanoparticles (PS-NPs) was investigated in the presence of six hydrophobic and hydrophilic dissolved organic matter (DOM) isolates and biopolymers (effluent OM) in NaCl and CaCl2 solutions using time-resolved dynamic light scattering. Results showed that the stability of PS-NPs mainly depends on OM characteristics and ionic composition. Due to cation bridging, the aggregation rate of PS-NPs in Ca2+-containing solutions was significantly higher than at similar Na+-ionic strength. Biopolymers rich in protein and carbohydrate moieties showed higher affinity to the surface of PS-NPs than the other DOM isolates in the absence of both Ca2+ and Na+. Overall, the stability of PS-NPs followed the order of biopolymers > hydrophobic isolates > hydrophilic isolates in the presence of Na+ and biopolymers > hydrophilic isolates > hydrophobic isolates in Ca2+-containing solutions. In the presence of high MW structures (biopolymers), PS-NPs aggregation in both NaCl and CaCl2 solutions was attributed to steric repulsive forces. The impact of hydrophilic and hydrophobic isolates on PS-NPs aggregation highly relied on the ionic composition. Coagulation was an effective pretreatment for PS-NPs removal. Using inductively coupled plasma-mass spectrometry, higher removals were recorded with Al2(SO4)3 in the absence of DOM, while PACl more efficiently coagulated PS-NPs in the presence of DOM isolates.

Dry biofilms on polystyrene surfaces: the role of oxidative treatments for their mitigation.

Candida auris and Staphylococcus aureus are associated with a wide range of infections, as they exhibit multidrug resistance - a growing health concern. In this study, gaseous ozone, and ultraviolet-C (UVC) radiation are applied as infection control measures to inactivate dry biofilms of these organisms on polystyrene surfaces. The dosages utilised herein are 1000 and 3000 ppm.min for ozone and 2864 and 11592 mJ.cm-2 for UVC. Both organisms showed an increased sensitivity to UVC relative to ozone exposure in a bespoke decontamination chamber. While complete inactivation of both organisms (>7.5 CFU log) was realized after 60 mins of UVC application, this could not be achieved with ozonation for the same duration. However, a combined application of ozone and UVC yielded complete inactivation in only 20 mins. For both treatment methods, it was observed that dry biofilms of S. aureus were more difficult to inactivate than dry biofilms of C. auris. Compared to dry biofilms of C. auris, micrographs of wet C. auris biofilms revealed the presence of an abundance of extracellular material after treatments. Interestingly, wet biofilms were more difficult to inactivate than dry biofilms. These insights are crucial to preventing recalcitrant and recurrent infections via contact with contaminated polymeric surfaces.

Oxidative treatment can inactivate dry biofilms formed by C. auris and S. aureus.Both organisms showed an increased sensitivity to UVC compared to ozone.Dry biofilms of S. aureus were more difficult to inactivate than dry biofilms of C. auris.Wet biofilms of C. auris display a spongy appearance compared to its dry biofilms.Wet biofilms of C. auris proved more difficult to inactivate than its dry biofilms.

Histopathological lesions of the gastrointestinal tract associated with the use of polystyrene sulfonate and sevelamer: a meta-analysis.

Background: Gastrointestinal severe adverse events such as ulceration and perforation have been reported for sodium or calcium polystyrene sulfonate and sevelamer. Howewer, their role in the pathogenesis is unclear. Chronic kidney disease is a well known risk factor, while the role of hypertension and/or diabetes is uncertain. Methods: A meta-analysis of the published literature was conducted to review the clinical features, risk factors and histopathological findings of patients who experienced gastrointestinal adverse events after administration of polystyrene sulfonate or sevelamer. Results: The meta-analysis indicated that patients were more likely to show necrosis and/or perforation when the resin used was polystyrene sulfonate compared to sevelamer (p < 0.001). Death was more likely in patients taking polystyrene sulfonate compared to sevelamer (p < 0.001). Discussion: The results show that sevelamer is more likely to lead to inflammation or ulceration in the gastrointestinal tract than polystyrene sulfonate, which is more likely to be associated with severe gastrointestinal adverse events such as necrosis and/or perforation. Polystyrene sulfonate is significantly associated with death compared to sevelamer.

Early-life exposure to polystyrene micro- and nanoplastics disrupts metabolic homeostasis and gut microbiota in juvenile mice with a size-dependent manner.

Early-life exposure to different sizes of micro- and nanoplastics (MNPs) affects biotoxicity, which is related not only to the dose but also directly to particle size. In this study, pregnant ICR mice received drinking water containing 5 µm polystyrene microplastics (5 µm PS-MPs) or 0.05 µm polystyrene nanoplastics (0.05 µm PS-NPs) from pregnancy to the end of lactation. Histopathological and molecular biological detection, 16s rRNA sequencing for intestinal flora analysis, and targeted metabolomics analysis were used to look into how early-life exposure to MNPs of various sizes affects young mice's growth and development, gut flora, and metabolism. The outcomes shown that 0.05 µm and 5 µm PS-MNPs can pass through the placental and mammary barriers, and MNPs accumulating in various organs were size-dependent: the greater the accumulation in organs, the smaller the particle size. Further studies found that the larger 5 µm PS-MPs caused only small accumulation in organs, with the main health hazard being the disruption of intestinal barrier and liver function, indirectly causing gut dysbiosis and metabolic disorders. In contrast, the smaller 0.05 µm PS-NPs caused excessive accumulation in organs, not only impaired the function of the intestine and liver, but also caused direct mechanical damage to physical tissues, and ultimately resulted in more severe intestinal and metabolic disorders. Our findings underline the size-dependent risks associated with micro- and nanoplastics exposure early in life and highlight the necessity for tailored approaches to address health damages from early MNPs exposure.

Deciphering the links: Fragmented polystyrene as a driver of skin inflammation.

Nano- and microplastics (NMPs), ubiquitous in the environment, pose significant health risks. We report for the first time a comprehensive study using in-vitro, in-vivo, and ex-vivo models to investigate the penetration and inflammatory effects of fragmented polystyrene (fPS) on human skin, including the analysis of both penetration depth and fPS amounts that penetrate the skin. Human keratinocyte (HaCaT) and human dermal fibroblast (HDF) cells exposed to fPS exhibited notable internalization and cytotoxicity. In a 3D human skin model, fPS particles penetrated the dermal layer within one hour, with an average maximum penetration of 4.7 µg for particles smaller than 2 µm. Similarly, mouse dorsal skin and human abdominal skin models confirmed fPS penetration. RNA sequencing revealed substantial upregulation of inflammatory genes, including IL-1α, IL-1ß, IL-18, IL-6, IL-8, ICAM-1, FOS, and JUN, following fPS exposure. These findings were validated at both the mRNA and protein levels, indicating a robust inflammatory response. Notably, the inflammatory response in both the 3D human skin and mouse models increased in a dose-dependent manner, underscoring the toxicological impact of fPS on skin health. This study provides crucial insights into the mechanisms through which NMPs affect human health and underscores the need for further research to develop effective mitigation strategies.

Mitogenomic profiling and gut microbial analysis of the newly identified polystyrene-consuming lesser mealworm in Kenya.

Plastic waste has recently become a major global environmental concern and one of the biggest challenges has been seeking for alternative management options. Several studies have revealed the potential of several coleopteran species to degrade plastics, and this is the first research paper on plastic-degradation potential by lesser mealworms from Africa. This study evaluated the whole mitogenomic profile of the lesser mealworm to further identify the insect. The ability of the mealworm to consume Polystyrene (PS) was also evaluated alongside its associated gut microbiota diversity. Our results showed a complete circular mitochondrial genome which clustered closely to the Alphitobius genus but also suggested that our insect might be a new subspecies which require further identification. During the PS feeding trials, overall survival rates of the larvae decreased when fed a sole PS diet while PS intake was observed to increase over a 30-day period. The predominant bacteria observed in larvae fed PS diets were Kluyvera, Lactococcus, Klebsiella, Enterobacter, and Enterococcus, while Stenotrophomonas dominated the control diet. These findings demonstrated that the newly identified lesser mealworm can survive on a PS diet and has a consortium of important bacteria strongly associated with PS degradation. This work provides a better understanding of bioremediation applications, paving the way for further research into the metabolic pathways of plastic-degrading microbes and bringing hope to solving plastic waste pollution while providing high-value insect protein towards a circular economy.

Disturbance of mitochondrial dynamics led to spermatogenesis disorder in mice exposed to polystyrene micro- and nanoplastics.

The widespread presence of polystyrene micro- and nanoplastics (PS-MPs/NPs) in the environment poses a threat to the health of the population. Animal studies have shown PS-MPs/NPs had male reproductive toxicity, while its mechanisms are unclear. To investigate that, male Balb/c mice were randomized into 3 groups: the control, 1 µm PS-MPs and 70 nm PS-NPs group, and they were given PS-MPs/NPs by intratracheal instillation for 28 days. Results revealed that PS-MPs/NPs up-regulated the expression of mitochondrial fission related factors (p-DRP1/DRP1, FIS1) and down-regulated the level of mitochondrial fusion related factors (MFN1/2, OPA1), causing over mitochondrial fission, which activating mitochondrial apoptotic pathway (BAX, Cleaved-Caspase9, Cleaved-Caspase3), resulting in cell apoptosis. Moreover, the damaged structure of mitochondria and over mitochondrial fission caused mitochondrial DNA (mtDNA) to translocate from mitochondria to cytoplasm, which activated DNA sensing pathway (cGAS-STING) and induced cell pyroptosis in testis by raising the expression of inflammation factors (NLRP3, ASC, Caspase1 p20, IL-1ß). In vitro, by using the mitochondrial fission inhibitor Mdivi-1, it is found that PS-NPs-induced cell apoptosis and pyroptosis were associated with over mitochondrial fission. Taken together, we conclude that PS-MPs/NPs cause spermatogenesis disorder possibly through damaging mitochondrial structure and dynamic homeostasis, which on the one hand results in mitochondria-mediated apoptosis, and on the other hand leads to mtDNA mislocalization, activating cGAS-STING pathway and inflammation, ultimately resulting in pyroptosis. This study may provide a new reference to the potential mechanisms of male reproductive toxicity caused by PS-MPs/NPs.

Polystyrene nanoplastic exposure actives ferroptosis by oxidative stress-induced lipid peroxidation in porcine oocytes during maturation.

BACKGROUND: Polystyrene nanoplastics (PS-NPs) are becoming increasingly prevalent in the environment with great advancements in plastic products, and their potential health hazard to animals has received much attention. Several studies have reported the toxicity of PS-NPs to various tissues and cells; however, there is a paucity of information about whether PS-NPs exposure can have toxic effects on mammalian oocytes, especially livestock. Herein, porcine oocytes were used as the model to investigate the potential effects of PS-NPs on mammalian oocytes. RESULTS: The findings showed that different concentrations of PS-NPs (0, 25, 50 and 100 µg/mL) entering into porcine oocytes could induce mitochondrial stress, including a significant decrease in mitochondrial membrane potential (MMP), and the destruction of the balance of mitochondrial dynamic and micromorphology. Furthermore, there was a marked increase in reactive oxygen species (ROS), which led to oocyte lipid peroxidation (LPO). PS-NPs exposure induced abnormal intracellular iron overload, and subsequently increased the expression of transferrin receptor (TfRC), solute carrier family 7 member 11 (SLC7a11), and acyl-CoA synthetase long-chain family member 4 (ACSL4), which resulted in ferroptosis in oocytes. PS-NPs also induced oocyte maturation failure, cytoskeletal dysfunction and DNA damage. Cotreatment with 5 µmol/L ferrostatin-1 (Fer-1, an inhibitor of ferroptosis) alleviated the cellular toxicity associated with PS-NPs exposure during porcine oocyte maturation. CONCLUSIONS: In conclusion, PS-NPs caused ferroptosis in porcine oocytes by increasing oxidative stress and altering lipid metabolism, leading to the failure of oocyte maturation.

Polystyrene nanoplastics enhance poxvirus preference for migrasome-mediated transmission.

Since the emergence of a global outbreak of mpox in 2022, understanding the transmission pathways and mechanisms of Orthopoxviruses, including vaccinia virus (VACV), has become paramount. Nanoplastic pollution has become a significant global issue due to its widespread presence in the environment and potential adverse effects on human health. These emerging pollutants pose substantial risks to both living organisms and the environment, raising serious health concerns related to their proliferation. Despite this, the effects of nanoparticles on viral transmission dynamics remain unclear. This study explores how polystyrene nanoparticles (PS-NPs) influence the transmission of VACV through migrasomes. We demonstrate that PS-NPs accelerate the formation of migrasomes early in the infection process, facilitating VACV entry as soon as 15 h post-infection (hpi), compared to the usual onset at 36 hpi. Immunofluorescence and transmission electron microscopy (TEM) reveal significant co-localization of VACV with migrasomes induced by PS-NPs by 15 hpi. This interaction coincides with an increase in lipid droplet size, attributed to higher cholesterol levels influenced by PS-NPs. By 36 hpi, migrasomes exposed to both PS-NPs and VACV exhibit distinct features, such as retraction fibers and larger lipid droplets, emphasizing their critical role in cargo transport during viral infections. These results suggest that PS-NPs may act as modulators of viral transmission dynamics through migrasomes, with potential implications for antiviral strategies and environmental health.

Impacts of root exudates on the toxic response of Chrysanthemum coronarium L. to the co-pollution of nanoplastic particles and tetracycline.

Nano polystyrene (PS) particles and antibiotics universally co-exist, posing a threat to crop plants and hence human health, nevertheless, there is limited research on their combined toxic effects along with major influential factors, especially root exudates, on crop plants. This study aimed to investigate the response of Chrysanthemum coronarium L. to the co-pollution of nanoplastics and tetracycline (TC), as well as the effect of root exudates on this response. Based on a hydroponic experiment, the biochemical and physiological indices of Chrysanthemum coronarium L. were measured after 7 days of exposure. Results revealed that the co-pollution of TC and PS caused significant oxidative damage to the plants, resulting in reduced biomass. Amongst the two contaminants, TC played a more prominent role. PS could enter the root tissue, and the uptake of TC and PS by plant roots was synergetic. Malic acid, oxalic acid, and formic acid could explain 65.1% of the variation in biochemical parameters and biomass of the roots. These compounds affected the photosynthesis and biomass of Chrysanthemum coronarium L. by gradually lowering root reactive oxygen species (ROS) and leaf ROS. In contrast, the impact of rhizobacteria on the toxic response of the plants was relatively minor. These findings suggested that root exudates could alleviate the toxic response of plants to the co-pollution of TC and PS. This study enhances our understanding of the role of root exudates, providing insights for agricultural management and ensuring food safety.

Lack of effects of polystyrene micro- and nanoplastics on activity and expression of human drug transporters.

Micro- and nanoplastics (MPs/NPs) constitute emerging and widely-distributed environmental contaminants to which humans are highly exposed. They possibly represent a threat for human health. In order to identify cellular/molecular targets for these plastic particles, we have analysed the effects of exposure to manufactured polystyrene (PS) MPs and NPs on in vitro activity and expression of human membrane drug transporters, known to interact with chemical pollutants. PS MPs and NPs, used at various concentrations (1, 10 or 100 µg/mL), failed to inhibit efflux activities of the ATP-binding cassette (ABC) transporters P-glycoprotein, MRPs and BCRP in ABC transporter-expressing cells. Furthermore, PS particles did not impair the transport of P-glycoprotein or BCRP substrates across intestinal Caco-2 cell monolayers. Uptake activities of solute carriers (SLCs) such as OCT1 and OCT2 (handling organic cations) or OATP1B1, OATP1B3, OATP2B1, OAT1 and OAT3 (handling organic anions) were additionally not altered by PS MPs/NPs in HEK-293 cells overexpressing these SLCs. mRNA expression of ABC transporters and of the SLCs OCT1 and OATP2B1 in Caco-2 cells and human hepatic HepaRG cells were finally not impaired by a 48-h exposure to MPs/NPs. Altogether, these data indicate that human drug transporters are unlikely to be direct and univocal targets for synthetic PS MPs/NPs.

Effects of polystyrene micro- and nanoplastics on androgen- and estrogen receptor activity and steroidogenesis in vitro.

While many plastic additives show endocrine disrupting properties, this has not been studied for micro- and nanoplastics (MNPs) particles despite their ubiquitous presence in humans. The objective of this study was to determine the effects of various sizes and concentrations of polystyrene (PS)-MNPs (50-10,000 nm, 0.01-100 µg/mL) on estrogen- and androgen receptor (ER and AR) activity and steroidogenesis in vitro. Fluorescent (F)PS-MNPs of ≤1000 nm were internalized in VM7 and H295R cells and FPS-MNPs ≤200 nm in AR-ecoscreen cells. H295R cells displayed the highest uptake and particles were closer to the nucleus than other cell types. None of the sizes and concentrations PS-MNPs tested affected ER or AR activity. In H295R cells, PS-MNPs caused some statistically significant changes in hormone levels, though these showed no apparent concentration or size-dependent patterns. Additionally, PS-MNPs caused a decrease in estriol (E3) with a maximum of 37.5 % (100 µg/mL, 50 nm) and an increase in gene expression of oxidative stress markers GPX1 (1.26-fold) and SOD1 (1.23-fold). Taken together, our data show limited endocrine-disrupting properties of PS-MNPs in vitro. Nevertheless the importance of E3 in the placenta warrants further studies in the potential effects of MNPs during pregnancy.