Polystyrene Nanoplastics Research Articles

Toxicity to the Male Reproductive System after Exposure to Polystyrene Nanoplastics: A Macrogenomic and Metabolomic Analysis.

Nanoplastics (NPs) cause serious contamination of drinking water and potential damage to human health. This study aimed to investigate the effects of NPs with different particle sizes and concentrations on the reproductive function of male mice. In this study, free drinking water exposure was used to expose male BALB/C mice to PS-NPs (20 nm, 200 nm, and 1000 nm) at 0.1 mg/L, 1 mg/L, and 5 mg/L for 4 months. The male reproductive function of the mice was assessed after NPs exposure, and fecal and blood samples were collected for macrogenomics and metabolomics. The results showed that PS-NPs resulted in mice with reduced testicular organ coefficients, decreased sperm quality, altered testicular tissue structure, disturbed sex hormone levels, and abnormal levels of inflammatory factors and oxidative stress. Furthermore, this study found that NP exposure affected the alteration of gut communities and metabolic pathways related to male reproduction, such as Clostridium and glutathione metabolism. Importantly, we found an effect of NP particle size on reproductive function. In the future, more attention should be paid to the smaller particle sizes of NPs.

Internalization of nano- and micro-plastics in human erythrocytes leads to oxidative stress and estrogen receptor-mediated cellular responses

Plastic material versatility has resulted in a substantial increase in its use in several sectors of our everyday lives. Consequently, concern regarding human exposure to nano-plastics (NPs) and micro-plastics (MPs) has recently increased. It has been shown that plastic particles entering the bloodstream may adhere to the erythrocyte surface and exert adverse effects following erythrocyte aggregation and adhesion to blood vessels. Here, we explored the effects of polystyrene nano-plastics (PS-NPs) and micro-plastics (PS-MPs) on human erythrocytes. Cellular morphology, binding/internalization of PS-NPs and PS-MPs, oxidative stress parameters, as well as the distribution and anion exchange capability of band 3 (anion exchanger 1; SLC4A1) have been analyzed in human erythrocytes exposed to 1 μg/mL PS-NPs or PS-MPs for 3 and 24 h, respectively. The data obtained showed significant modifications of the cellular shape after exposure to PS-NPs or PS-MPs. In particular, a significantly increased number of acanthocytes, echinocytes and leptocytes were detected. However, the percentage of eryptotic cells (<1 %) was comparable to physiological conditions. Analytical cytology and confocal microscopy showed that PS-NPs and PS-MPs bound to the erythrocyte plasma membrane, co-localized with estrogen receptors (Erα/ERβ), and were internalized. An increased trafficking from the cytosol to the erythrocyte plasma membrane and abnormal distribution of ERs were also observed, consistent with ERα-mediated binding and internalization of PS-NPs. An increased phosphorylation of ERK1/2 and AKT kinases indicated that an activation of the ER-modulated non-genomic pathway occurred following exposure to PS-NPs and PS-MPs. Interestingly, PS-NPs or PS-MPs caused a significant production of reactive oxygen species, resulting in an increased lipid peroxidation and protein sulfhydryl group oxidation. Oxidative stress was also associated with an altered band 3 ion transport activity and increased oxidized haemoglobin, which led to abnormal clustering of band 3 on the plasma membrane. Taken together, these findings identify cellular events following the internalization of PS-NPs or PS-MPs in human erythrocytes and contribute to elucidating potential oxidative stress-related harmful effects, which may affect erythrocyte and systemic homeostasis.

Transcriptome mechanisms of dandelion under stress of polystyrene and dibutyl phthalate and quantitative tracing of nanoplastics

Polystyrene nanoplastics (PS NPs) and dibutyl phthalate (DBP) pollution pose significant risks to ecosystems and contribute to bioaccumulation in plants, yet uptake mechanisms and combined toxicity are poorly understood. We used fluorescent labeling and europium-doped PS NPs to reveal the absorption and translocation of NPs by dandelions and conducted a transcriptomic analysis under PS NPs and DBP exposure. The results indicated that NPs are transported horizontally through the intercellular gaps at the root tips and primary root-lateral root junctions via the apoplastic pathway, followed by longitudinal transport through the xylem vessels under the transpiration stream. Co-exposure significantly reduced the bioconcentration factors of dandelion seedlings by 113 % but increased the NP transfer factors by 33.8 %. Transcriptomic analysis confirmed that exposure to PS NPs and DBP activated gene expression in dandelion shoots and roots. The differentially expressed genes were primarily involved in the photosynthesis, plant hormone signal transduction, and phenylpropanoid biosynthesis pathways. Weighted gene co-expression network analysis identified key genes and hub transcription factors playing crucial roles in regulating dandelion's response to combined stress. Our study provides new insights into the plant toxicity mechanism underlying the interaction between PS NPs and DBP, highlighting the adverse effects of the combined pollution on plant health.

Influence of macromolecules and electrolytes on heteroaggregation kinetics of polystyrene nanoplastics and goethite nanoparticles in aquatic environments

Fate and transport of nanoplastics in aquatic environments are affected by their heteroaggregation with minerals in the presence of macromolecules. This study investigated the heteroaggregation of polystyrene nanoplastics (PSNPs) with goethite nanoparticles (GNPs) under the influence of macromolecules [humic acid (HA), bovine serum albumin (BSA), and DNA] and electrolytes. Under 1 mg C/L macromolecule, raising electrolyte concentration promoted heteroaggregation via charge screening, except that calcium bridging with HA also enhanced heteroaggregation at CaCl2 concentration above 5 mM. At all NaCl concentrations and CaCl2 concentration below 5 mM, 1 mg C/L macromolecules strongly retarded heteroaggregation, ranking BSA > DNA > HA. Raising macromolecule concentration strengthened such stabilization effect of all macromolecules in NaCl solution and that of DNA and BSA in CaCl2 solution by enhancing steric hindrance. However, 0.1 mg C/L BSA slightly promoted heteroaggregation in CaCl2 solution due to stronger electrostatic attraction than steric hindrance. In CaCl2 solution, raising HA concentration strengthened its destabilization effect via calcium bridging. Macromolecules having more compact globular structure and higher molecular weight may exert greater steric hindrance to inhibit heteroaggregation more effectively. This study provides new insights on the effects of macromolecules and electrolytes on heteroaggregation between nanoplastics and iron minerals in aquatic environments.

Evaluating the role of soil EPS in modifying the toxicity potential of the mixture of polystyrene nanoplastics and xenoestrogen, Bisphenol A (BPA) in Allium cepa L.

The coexistence of emerging pollutants like nanoplastics and xenoestrogen chemicals such as Bisphenol A (BPA) raises significant environmental concerns. While the individual impacts of BPA and polystyrene nanoplastics (PSNPs) on plants have been studied, their combined effects are not well understood. This study examines the interactions between eco-corona formation, physicochemical properties, and cyto-genotoxic effects of PSNPs and BPA on onion (Allium cepa) root tip cells. Eco-corona formation was induced by exposing BPA-PSNP mixtures to soil extracellular polymeric substances (EPS), and changes were analyzed using 3D-EEM, TEM, FTIR, hydrodynamic diameter, and contact angle measurements. Onion roots were treated with BPA (2.5, 5, and 10 mgL-1) combined with plain, aminated, and carboxylated PSNPs (100 mgL-1), with and without EPS interaction. Toxicity was assessed via cell viability, oxidative stress markers (superoxide radical, total ROS, hydroxyl radical), lipid peroxidation, SOD and catalase activity, mitotic index, and chromosomal abnormalities. BPA alone increased cytotoxic and genotoxic parameters in a dose-dependent manner. BPA with aminated PSNPs exhibited the highest toxicity among the pristine mixtures, revealing increased chromosomal abnormalities, oxidative stress, and cell mortality with rising BPA concentrations. In-silico experiments demonstrated the relationship between superoxide dismutase (SOD), catalase enzymes, PSNPs, BPA, and their mixtures. EPS adsorption notably reduced cyto-genotoxic effects, lipid peroxidation, and ROS levels, mitigating the toxicity of BPA-PSNP mixtures.

Influence of algal-extracellular polymeric substances (EPS) on the pristine and combined toxicity of TiO2 NPs and PSNPs in Artemia salina: Eco-corona enhances the toxic effects

The study on the influence of Natural Organic Matter (NOM) over the individual and combined effects of different nanomaterials on marine species is pertinent. The current study explores the role of Extracellular Polymeric Substances (EPS) in influencing the individual and combined toxic effects of polystyrene nanoplastics (PSNPs) viz. aminated (NH2-PSNPs), carboxylated (COOH-PSNPs), and plain PSNPs and TiO2 NPs in the marine crustacean, Artemia salina. A. salina was interacted with pristine PSNPs, pristine TiO2 NPs, EPS incubated PSNPs, EPS incubated TiO2 NPs, binary mixture of PSNPs and TiO2 NPs, and EPS adsorbed binary mixture of PSNPs and TiO2 NPs for 48 h. The present study proves that, when compared to the pristine toxicity of PSNPs and TiO2 NPs, the coexposure of TiO2 NPs with PSNPs resulted in increased toxicity. The adsorption of algal EPS on the NMs (both in their pristine and combined forms) significantly increased the toxic nature of the NMs against A. salina. It was observed that with an increase in the hydrodynamic diameter of the particles, the mortality, oxidative stress, and ingestion of the NMs by A. salina increased. The uptake of Ti by A. salina from 8 mg/L TiO2 NPs, EPS adsorbed 8 mg/L TiO2 NPs, 8 mg/L TiO2 NPs + NH2-PSNPs and the EPS adsorbed mixture of 8 mg/L TiO2 NPs, 8 mg/L TiO2 NPs + NH2-PSNPs was observed to be 0.043, 0.047, 0.186, and 0.307 mg/g of A. salina. The adsorption of algal EPS on the NMs (both in their pristine and combined forms) significantly increased the toxic nature of the NMs against A. salina. The major outcomes from the current study highlight the role of EPS in exacerbating the toxicity of NMs in marine crustaceans.

The impact of polystyrene nanoplastics on plants in the scenario of increasing temperatures: The case of Azolla filiculoides Lam

There are great concerns for the accumulation in the environment of small dimension plastics, such as micro- and nanoplastics. Due to their small size, which facilitates their uptake by organisms, nanoplastics are of particular concern. The toxic effects of nanoplastics on plants are already reported in the literature, however nothing is known, to date, about the possible effects of climate change, in particular of increasing temperatures, on their toxicity for plants. To address this issue, plants of the water fern Azolla filiculoides were grown at optimal (25 °C) or high (35 °C) temperature, with or without polystyrene nanoplastics, and the effects of these stressors were assessed using a multidisciplinary approach. Green fluorescent polystyrene nanoplastics were used to track their possible uptake by A. filiculoides. The development and physiology of our model plant was adversely affected by both nanoplastics and high temperatures. Overall, histological, morphological, and photosynthetic parameters worsened under co-treatment, in accordance with the increased uptake of nanoplastics under higher temperature, as observed by fluorescence images. Based on our findings, the concern regarding the potential for increased toxicity of pollutants, specifically nanoplastics, at high temperatures is well-founded and warrants attention as a potential negative consequence of climate change. Additionally, there is cause for concern regarding the increase in nanoplastic uptake at high temperatures, particularly if this phenomenon extends to food and feed crops, which could lead to greater entry into the food chain.

Polystyrene nanoplastics of different particle sizes regulate the polarization of pro-inflammatory macrophages

Microplastics (MPs) are defined as plastic particles smaller than 5 mm in size, and nanoplastics (NPs) are those MPs with a particle size of less than 1000 nm or 100 nm. The prevalence of MPs in the environment and human tissues has raised concerns about their potential negative effects on human health. Macrophages are the major defence against foreign substances in the intestine, and can be polarized into two types: the M1 phenotype and the M2 phenotype. However, the effect of NPs on the polarization of macrophages remains unclear. Herein, we selected polystyrene, one of the most plastics in the environment and controlled the particle sizes at 50 nm and 500 nm respectively to study the effects on the polarization of macrophages. We used mouse RAW264.7 cell line models in this macrophage-associated study. Experiments on cell absorption showed that macrophages could quickly ingest polystyrene nanoplastics of both diameters with time-dependent uptake. Compared to the untreated group and 10 μg/mL treatment group, macrophages exposed to 50 μg/mL groups (50 nm and 500 nm) had considerably higher levels of CD86, iNOS, and TNF-α, but decreased levels of aCD206, IL-10, and Arg-1. According to these findings, macrophage M1 and M2 polarization can both be induced and inhibited by 50 μg/mL 50 nm and 500 nm polystyrene nanoplastics. This work provided the first evidence of a possible MPs mode of action with appropriate concentration and size through the production of polarized M1, providing dietary and environmental recommendations for people, particularly those with autoimmune and autoinflammatory illnesses.

Impact of polystyrene nanoplastics on apoptosis and inflammation in zebrafish larvae: Insights from reactive oxygen species perspective

In recent years, there has been a growing focus on the toxicity and mortality induced by nanoplastics (NPs) in aquatic organisms. However, studies investigating mechanisms underlying oxidative stress (OS), apoptosis, and inflammation induced by NPs in fish remain limited. This study observed that polystyrene NPs (PS-NPs) were accumulated into zebrafish larvae and zebrafish embryonic fibroblast (ZF4 cells), accompanied by the occurrence of pathological damage both at the cellular and tissue–organ level. Additionally, the transcriptional up-regulation of NADPH oxidases (NOXs) and subsequent excessive generation of reactive oxygen species (ROS) resulted in notable changes in the relative mRNA and protein expression levels associated with antioxidant oxidase systems in larvae. Furthermore, the study identified the impact of NPs on mitochondrial ultrastructural, resulting in mitochondrial depolarization and downregulation of mRNA expression related to the electron transport chain due to excessive ROS generation. Short-term exposure to NPs also triggered apoptosis and inflammation in zebrafish larvae, evident from significant up-regulation in mRNA expressions of proapoptotic factors and NF-κB proinflammatory signaling pathway, as well as increased transcription and protein levels of pro-inflammatory factors in larvae. Inhibition of intracellular excessive ROS effectively reduced the induction of apoptosis, NF-κB P65 nuclear migration levels, and cytokine secretion, underscoring OS as a pivotal factor throughout the process of apoptosis and inflammatory responses induced by NPs. This research significantly advances our comprehension of biological effects and underlying mechanisms of NPs in freshwater fish.

3D imaging photocatalytically degraded micro- and nanoplastics

Microplastics (MPs) and nanoplastics have been an emerging global concern, with hazardous effects on plant, animal, and human health. Their small size makes it easier for them to spread to various ecosystems and enter the food chain; they are already widely found in aqueous environments and within aquatic life, and have even been found within humans. Much research has gone into understanding micro-/nanoplastic sources and environmental fate, but less work has been done to understand their degradation. Photocatalytic degradation is a promising green technique that uses visible or ultraviolet light in combination with photocatalyst to degrade plastic particles. While complete degradation, reducing plastics to small molecules, is often the goal, partial degradation is more common. We examined microscale polyethylene (PE) (125–150 µm in diameter) and nanoscale polystyrene (PS) (∼300 nm in diameter) spheres both before and after degradation using multiple imaging techniques, especially electron tomography in addition to conventional electron microscopy. Electron tomography is able to image the 3D exterior and interior of the nanoplastics, enabling us to observe within aggregates and inside degraded spheres, where we found potentially open interior structures after degradation. These structures may result from differences in degradation and aggregation behavior between the different plastic types, with our work finding that PE MPs typically cracked into sharp fragments, while PS nanoplastics often fragmented into smoother, more curved shapes. These and other differences, along with interior and 3D surface images, provide new details on how the structure and aggregation of PE MPs and PS nanoplastics changes when degraded, which could influence how the resulting worn particles are collected or treated further.

Electrolyte-Gated Carbon Nanotube Field-Effect Transistor-Based Sensors for Nanoplastics Detection in Seawater: A Study of the Interaction between Nanoplastics and Carbon Nanotubes.

Plastics accumulating in the environment are nowadays of great concern for aquatic systems and for the living organisms populating them. In this context, nanoplastics (NPs) are considered the major and most dangerous contaminants because of their small size and active surface, which allow them to interact with a variety of other molecules. Current methods used for the detection of NPs rely on bulky and expensive techniques such as spectroscopy. Here we propose, for the first time, a novel, fast, and easy-to-use sensor based on an electrolyte-gated field-effect transistor (EG-FET) with a carbon nanotube (CNT) semiconductor (EG-CNTFET) for the detection of NPs in aquatic environments, using polystyrene NPs (PS-NPs) as a model material. In particular, as a working mechanism for the EG-CNTFETs we exploited the ability of CNTs and PS to form noncovalent interactions. Indeed, in our EG-CNTFET devices, the interaction between NPs and CNTs caused a change in the electric double layers. A linear increase in the corrected on current (*ION) of the EG-CNTFETs, with a sensitivity of 9.68 μA/(1 mg/mL) and a linear range of detection from 0.025 to 0.25 mg/mL were observed. A π-π interaction was hypothesized to take place between the two materials, as indicated by an X-ray photoelectron spectroscopy analysis. Using artificial seawater as an electrolyte, to mimic a real-case scenario, a linear increase in *ION was also observed, with a sensitivity of 6.19 μA/(1 mg/mL), proving the possibility to use the developed sensor in more complex solutions, as well as in low concentrations. This study offers a starting point for future exploitation of electrochemical sensors for NP detection and identification.

Toxicity of environmental and polystyrene plastic particles on the bivalve Corbicula fluminea: focus on the molecular responses.

Among aquatic organisms, filter feeders are particularly exposed to the ingestion of microplastics (MPs) and nanoplastics (NPs). The present study investigates the effect of environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized plastic debris collected in the Garonne River (France), and polystyrene NPs (PS NPs) on the freshwater bivalve Corbicula fluminea. Organisms were exposed to plastic particles at three concentrations: 0.008, 10, and 100 μg L-1 for 21 days. Gene expression measurements were conducted in gills and visceral mass at 7 and 21 days to assess the effects of plastic particles on different functions. Our results revealed: (i) an up-regulation of genes, mainly involved in endocytosis, oxidative stress, immunity, apoptosis, and neurotoxicity, at 7 days of exposure for almost all environmental plastic particles and at 21 days of exposure for PS NPs in the gills, (ii) PS NPs at the three concentrations tested and ENV MPs at 0.008 μg L-1 induced strong down-regulation of genes involved in detoxication, oxidative stress, immunity, apoptosis, and neurotoxicity at 7 days of exposure in the visceral mass whereas ENV MPs at 10 and 100 μg L-1 and all ENV NPs induced less pronounced effects, (iii) overall, PS NPs and ENV MPs 0.008 μg L-1 did not trigger the same effects as ENV MPs 10 and 100 μg L-1 and all ENV NPs, either in the gills or the visceral mass at 7 and 21 days of exposure. This study highlighted the need to use MPs and NPs sampled in the environment for future studies as their properties induce different effects at the molecular level to living organisms.

Nasal instillation of polystyrene nanoplastics induce lung injury via mitochondrial DNA release and activation of the cyclic GMP-AMP synthase-stimulator of interferon genes-signaling cascade

Nanoplastics (NPs) are a common type of degraded plastic material associated with adverse health effects such as pulmonary injury. However, the molecular mechanism(s) underlying lung injury as caused by NPs remains uncertain. Thus, we herein investigated the pulmonary toxicity of NPs on RAW264.7 cells and C57BL/6 mice. Our in vitro study indicated that NPs induced oxidative stress, cell death, inflammation, and the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-signaling pathway. Mice in our in vivo study displayed significant pulmonary fibrosis, inflammation, apoptosis, necrosis, and excessive double-stranded DNA release into serum and bronchoalveolar lavage fluid. Our mechanistic exploration uncovered cGAS-STING-signaling activation as the leading cause of NPs-induced pulmonary fibrosis. The current study opens an avenue toward elucidating the role of the cGAS-STING-signaling pathway in NPs-induced pulmonary injury.

Integrated transcriptomic and metabolomic analysis reveals the underlying mechanisms for male reproductive toxicity of polystyrene nanoplastics in mouse spermatocyte-derived GC-2spd(ts) cells

BackgroundPolystyrene nanoplastics (PS-NPs), are ubiquitous pollution sources in human environments, posing significant biosafety and health risks. While recent studies, including our own, have illustrated that PS-NPs can breach the blood-testis barrier and impact germ cells, there remains a gap in understanding their effects on specific spermatogenic cells such as spermatocytes. Methods and resultsHerein, we employed an integrated approach encompassing phenotype, metabolomics, and transcriptomics analyses to assess the molecular impact of PS-NPs on mouse spermatocyte-derived GC-2spd(ts) cells. Optimal exposure conditions were determined as 24 h with 50 nm PS-NPs at 12.5 μg/mL and 90 nm PS-NPs at 50 μg/mL for subsequent multi-omics analysis. Our findings revealed that PS-NPs significantly influenced proliferation and viability, causing alterations in transcriptome and metabolome profiles. Transcriptomics analysis of GC-2spd(ts) cells exposed to PS-NPs indicated the pivotal involvement of cell proliferation and cycle, autophagy, ferroptosis, and redox reaction pathways in PS-NP-induced effects on the proliferation and viability of GC-2spd(ts) cells. Furthermore, metabolomics analysis identified major changes in amino acid metabolism, cyanoamino acid metabolism, and purine and pyrimidine metabolism following PS-NP exposure. ConclusionOur integrated approach, combining metabolomics and transcriptomics profiles with phenotype data, enhances our understanding of the adverse effects of PS-NPs on germ cells.

Female zebrafish (Danio rerio) exposure to polystyrene nanoplastics induces reproductive toxicity in mother and their offspring

Nanoplastics (NPs) have been commonly detected in aquatic ecosystems, and their negative effects on aquatic organisms have raised concerns in the scientific community and general public. The acute toxicity, neurotoxicity, and metabolic toxicity induced by NPs on fishes have been reported by many studies, although less attention has been focused on how mother exposed to NPs affected their offspring in aquatic organisms. Here, female zebrafish (F0) were exposed to 0, 200 and 2000 μg/L polystyrene nanoplastics (PS-NPs) for 42 d, with their offspring (F1) reared in clear water until sexual maturity. The results showed that PS-NPs were detected in various organs of F0 and F1. PS-NPs exposure significantly decreased gonadal 17-estradiol (E2), while increasing testosterone (T) contents. Lower levels of cyp19a1a, lhr and erα expressions in the 2000 μg/L group were consistent with a reduced number of mature oocytes (MO), but an increase in perinucleolar oocytes (PO). Interestingly, the expression of vtg was only up-regulated by 200 μg/L PS-NPs. After exposure, the egg production was dramatically reduced, but the hatching rate and heartbeat of F1 embryos from treated females were significantly higher than those observed in females from the control group. Maternal PS-NPs exposure significantly decreased the E2 and T levels in F1 adults, while PS-NPs exposure significantly up-regulated the sox9a but down-regulated the foxl2a in F1 larvae of 30 days post fertilization (dpf). This study showed that PS-NPs caused reproductive toxicity by changing the hypothalamic-pituitary-gonadal (HPG) axis-related genes, impairing the reproductive capacity of female zebrafish, affecting the development and disrupting the endocrine function of F1. These results suggested that PS-NPs had adverse effects on fish reproductive system both in the directly exposed generation and in their unexposed offspring.

Polystyrene Nanoplastics Induce Lipid Metabolism Disorder by Activating the PERK-ATF4 Signaling Pathway in Mice.

In recent years, the study of microplastics (MPs) and nanoplastics (NPs) and their effects on human health has gained significant attention. The impacts of NPs on lipid metabolism and the specific mechanisms involved remain poorly understood. To address this, we utilized high-throughput sequencing and molecular biology techniques to investigate how endoplasmic reticulum (ER) stress might affect hepatic lipid metabolism in the presence of polystyrene nanoplastics (PS-NPs). Our findings suggest that PS-NPs activate the PERK-ATF4 signaling pathway, which in turn upregulates the expression of genes related to lipid synthesis via the ATF4-PPARγ/SREBP-1 pathway. This activation leads to an abnormal accumulation of lipid droplets in the liver. 4-PBA, a known ER stress inhibitor, was found to mitigate the PS-NPs-induced lipid metabolism disorder. These results demonstrate the hepatotoxic effects of PS-NPs and clarify the mechanisms of abnormal lipid metabolism induced by PS-NPs.

Neonatal Exposure to Polystyrene Nanoplastics Impairs Microglia-Mediated Synaptic Pruning and Causes Social Behavioral Defects in Adulthood.

The increasing prevalence and persistence of nanoplastics (NPs) have become critical environmental concerns. These particles have the potential to enter the food chain and accumulate in living organisms, which exerts their adverse effects on human health. The release of nanoparticles from feeding bottles raises concerns about potential health issues, especially for newborns exposed to NPs at the neonatal stage. In this study, we examined the impacts of neonatal exposure to polystyrene nanoplastics (PS-NPs) on neurodevelopment. Our study demonstrates that exposure to PS-NPs in newborn mice impairs microglial autophagic function and energy metabolism, leading to the disruption of microglia-mediated synaptic pruning during early neurodevelopment. These mice subsequently develop social behavioral defects in adulthood, suggesting the long-lasting effects of neonatal PS-NP exposure on brain development and behavior. Together, these data provide insights into the mechanism by which PS-NPs affect early neurodevelopment, thus emphasizing the crucial need to address plastic pollution globally.

Fluorescent labeling of micro/nanoplastics for biological applications with a focus on “true-to-life" tracking

The increased environmental presence of micro-/nanoplastics (MNPLs) and the potential health risks associated with their exposure classify them as environmental pollutants with special environmental and health concerns. Consequently, there is an urgent need to investigate the potential risks associated with secondary MNPLs. In this context, using “true-to-life” MNPLs, resulting from the laboratory degradation of plastic goods, may be a sound approach. These non-commercial secondary MNPLs must be labeled to track their presence/journeys inside cells or organisms. Because the cell internalization of MNPLs is commonly analyzed using fluorescence techniques, the use of fluorescent dyes may be a sound method to label them. Five different compounds comprising two chemical dyes (Nile Red and Rhodamine-B), one optical brightener (Opticol), and two industrial dyes (Amarillo Luminoso and iDye PolyPink) were tested to determine their potential for such applications. Using commercial standards of polystyrene nanoplastics (PSNPLs) with an average size of 170 nm, different characteristics of the selected dyes such as the absence of impact on cell viability, specificity for plastic staining, no leaching, and lack of interference with other fluorochromes were analyzed. Based on the overall data obtained in the wide battery of assays performed, iDye PolyPink exhibited the most advantages, with respect to the other compounds, and was selected to effectively label “true-to-life” MNPLs. These advantages were confirmed using a proposed protocol, and labeling titanium-doped PETNPLs (obtained from the degradation of milk PET plastic bottles), as an example of “true-to-life” secondary NPLs. These results confirmed the usefulness of iDye PolyPink for labeling MNPLs and detecting cell internalization.

Amino-modified polystyrene nanoplastics induced multiple response of Artemia hemocytes

Polystyrene polymers cause severe toxicity to aquatic animals. However, the process and mechanisms of innate immunity of invertebrates living at the bottom of the food chain to these pollutants remain unclear. In this study, the blood system responses of zooplankton Artemia were assessed through in vivo and in vitro exposure to amino-modified polystyrene nanoplastics (PS-NH2 NPs). The results indicated that the LC50 values of PS-NH2 NPs were 1.09 μg·mL−1 over 48 h and 0.42 μg·mL−1 over 7 d. Based on the five hemocyte subpopulations identified in Artemia, in vitro exposure assays revealed that phagocytosis was performed by plasmocytes and granulocytes with phagocytic rate of 22.64 %. TEM analysis further showed that PS-NH2 NPs caused cytoplasm vacuolization, swollen mitochondria, and lipid processing disorder. Gene expression pattern results demonstrated that Spatzle, Tollip, Hsp70, Hsp90, Casp8, API5and Pxn were significantly upregulated upon acute and chronic exposure (p < 0.05), while chronic exposure could induce significantly upregulation of ProPO (p < 0.05). Moreover, PS-NH2 NPs exposure remarkably varied the hemolymph microbiota and hemogram, particularly by increasing the proportion of adipohemocytes and phagocytes (p < 0.05). Our findings suggest that PS-NH2 NPs induce different responses in Artemia hemocyte, as primarily reflected by phagocytic processes, expression of immune and apoptosis relating genes, cell fates, hemogram and hemolymph microbiota variations. These findings support the possibility of using Artemia hemocytes as bioindicator to estimate nanoplastics pollution, thus contributing to hematological toxicity research in response to nanoplastics.

New Insights into the Formation of Aggregates of Bidisperse Nano- and Microplastics in Water Based on the Analysis of In Situ Microscopy and Molecular Simulation.

Microplastics (MPs) and nanoplastics (NPs) in water pose a global threat to human health and the environment. To develop efficient removal strategies, it is crucial to understand how these particles behave as they aggregate. However, our knowledge of the process of aggregate formation from primary particles of different sizes is limited. In this study, we analyzed the growth kinetics and structures of aggregates formed by polystyrene MPs in mono- and bidisperse systems using in situ microscopy and image analysis. Our findings show that the scaling behavior of aggregate growth remains unaffected by the primary particle size distribution, but it does delay the onset of rapid aggregation. We also performed a structural analysis that reveals the power law dependence of aggregate fractal dimension (df) in both mono- and bidisperse systems, with mean df consistent with diffusion-limited cluster aggregation (DLCA) aggregates. Our results also suggest that the df of aggregates is insensitive to the shape anisotropy. We simulated molecular forces driving aggregation of polystyrene NPs of different sizes under high ionic strength conditions. These conditions represent salt concentration in ocean water and wastewater, where the DLVO theory does not apply. Our simulation results show that the aggregation tendency of the NPs increases with the ionic strength. The increase in the aggregation is caused by the depletion of clusters of ions from the NPs surface.