Microplastics destabilize lipid membranes by mechanical stretching

Antagonistic effects of polystyrene microplastics and tetracycline on Chlorella pyrenoidosa as revealed by infrared spectroscopy coupled with multivariate analysis

Microplastics and antibiotics are typical emerging contaminants in the environment, posing considerable risks to the ecosystem and human health. Previous studies have reported synergistic or antagonistic effects in the presence of both microplastics and antibiotics, destructing cell membrane, inhibiting photosynthetic capability, and inducing antioxidant enzyme activity. However, there is still lack of comprehensive understanding of the mechanisms. This study applied infrared biospectroscopy and multivariate analysis to explore the physiological and biochemical toxicity of polystyrene microplastics and tetracycline co-exposure on Chlorella pyrenoidosa. Either tetracycline or polystyrene microplastics alone posed toxicities on C. pyrenoidosa, mainly due to changes in photosynthetic content, cell membrane permeability, MDA content and antioxidant enzyme activity. Co-exposure of tetracycline and polystyrene microplastics exhibited an antagonistic effect. Infrared spectroscopy coupled with multivariate analysis isolated the discriminating biomarkers representing different toxicity mechanisms, successfully explaining the mechanism of antagonism as reducing ROS production, regulating antioxidant enzyme activity, stabilizing cell membrane, and interfering with signaling and protein synthesis. A random forest model was developed and satisfactorily recognized the toxicity of individual toxins (accuracy of 98.75 %, sensitivity of 99.22 % and specificity of 99.65 %). It also rapidly apportioned toxicity origin and evidenced that tetracycline contributed to the majority of binary toxicities. This study provided scientific guidance and a theoretical basis for assessing and apportioning the binary toxicities of emerging contaminants.

Polystyrene and polyethylene perturb the structure of membrane: An experimental and computational study

There are various types and mixtures of nanoplastics (NPs) that are ubiquitous in the environment. Nevertheless, it remains a challenge to investigate the membrane effects and in vivo processes of mixtures of NPs due to their compositional complexity. In the present study, a framework combining cell assays, molecular dynamics (MD) simulations, and toxicogenomic network analysis was implemented to elucidate the differential effects of polystyrene (PS), polyethylene (PE), and the PS-PE mixture on cell membrane integrity. The cellular experiments indicated that PS, PE, and the PS-PE mixture could induce leakage of intracellular substances across the cell membrane, thereby demonstrating membrane damage. Molecular dynamics simulations revealed that these NPs could surmount energy barriers to infiltrate lipid membranes, leading to the formation of membrane pores. Notably, the PS-PE mixture showed a stronger effect than the single component. As evidenced by both cellular experiments and MD simulations, this phenomenon might be resulted from the elevated affinity of the PS-PE mixture for the lipid bilayer. The characteristic enhanced its propensity to engage with membrane structures, thereby inducing more pronounced disruption of membrane integrity. The analysis of biological networks underscored metabolic disorders and oxidative stress as key pathways for hepatotoxicity induced by NPs, elucidating the membrane damage and hepatotoxic mechanisms of NP mixtures. The study established a critical framework for assessing health risks of diverse NPs and their mixtures, while providing novel insights into the multiscale characterization of toxicity mechanisms spanning from molecular interactions to pathway-level information.

Effects of micro- and nanoplastics on blood cells in vitro and cardiovascular parameters in vivo, considering their presence in the human bloodstream and potential impact on blood pressure

The adverse effects of plastics on the environment, wildlife, and human health have been extensively studied, yet their production remains unavoidable due to the lack of viable alternatives. Environmental fragmentation of larger plastic particles generates microplastics (MPs, 0.1-5000 μm) and nanoplastics (NPs, 1-100 nm), which can enter the bloodstream through inhalation or ingestion. This review examines whether MPs and NPs influence blood pressure. To address this question, relevant studies were analyzed based on predefined criteria. Due to anatomical barriers and microcirculatory dynamics, only NPs and small MPs are expected to enter the bloodstream under physiological conditions, although pathological states may alter this. In vitro research indicates that MPs and NPs negatively affect erythrocytes and endothelial cells, while rodent models suggest potential cardiovascular effects. Plastic particles and fibers have been detected in human blood, thrombi, atherosclerotic plaques, and various tissues. However, validated data on plastic particle-related blood pressure changes remain lacking. Despite limitations in their applicability to human physiology, preclinical models suggest that MPs and NPs circulate in the bloodstream, interact with blood cells, and contribute to vascular damage. Mechanisms such as endothelial injury, platelet activation, inflammation, and MPs/NPs accumulation in atherosclerotic plaques may contribute to blood pressure elevation but are unlikely to be the exclusive cause of hypertension. Further research is needed to clarify the role of plastic particles in blood pressure regulation. Standardized detection methods, real-world scenario-related models, and targeted human studies are essential to assessing cardiovascular risks associated with MP and NP exposure.

Acute and partial life-cycle toxicity of a tri-polymer blend of microplastics in the copepod Acartia tonsa

Microplastics are a prolific environmental contaminant that pose a risk to marine organisms. Ecotoxicological studies have identified microplastics can cause sub-lethal harm to aquatic biota. However, prior studies often lack comparability and environmental relevance, for example focussing upon monodisperse beads at extremely high concentrations. Copepods are keystone marine taxa that play vital roles in the marine food web and biogeochemical cycling. In this study, we adapted ISO methods to conduct acute and partial life-cycle toxicity tests exposing adult and juvenile life stages of the copepod Acartia tonsa to a fully characterised tri-polymer microplastic blend comprising cryoground polyethylene, polypropylene, and nylon particles (5-100 μm) at concentrations ranging 0-1000 μg L-1. The tests considered the toxicity of microplastics on a wide number of endpoints including adult survival, algal ingestion rates, egg production and size, larval development ratio and juvenile survival. Mortality, egg size and larval development ratio proved to be the most sensitive endpoints. The tri-polymer blend had an LC5072h value of 182 μg L-1 providing a baseline for future toxicity testing using this method.

Unraveling the impact of micro- and nano-sized polymethyl methacrylate on gut microbiota and liver lipid metabolism: Insights from oral exposure studies

Microplastics, particularly polymethyl methacrylate (PMMA), have emerged as significant environmental pollutants, with growing concerns about their impact on various biological processes. However, the effects of chronic PMMA exposure on hepatic lipid metabolism remain insufficiently studied. This research aimed to examine the consequences of chronic exposure to PMMA particles of different sizes (100 nm and 2 μm) on hepatic lipid metabolism in mice. Female C57BL/6J mice were administered PMMA particles in drinking water over an 8-week period, and the effects on intestinal and liver morphology and function were evaluated. Histopathological analyses, gut microbiota profiling, and serum and liver assays were conducted to assess oxidative stress, lipid metabolism-related biomarkers, and liver metabolomics. The results revealed that PMMA particles accumulated in both the liver and colon, causing liver injury characterized by elevated ALT and AST levels. The exposure also induced oxidative stress by inhibiting the NRF2/HO-1 signaling pathway. Furthermore, PMMA exposure resulted in significant alterations to the gut microbiota and hepatic metabolism. These changes were linked to increased microbial diversity, which impacted cholesterol metabolism through the gut-liver axis. Additionally, the activation of the PI3K/AKT/PPARγ signaling pathway disrupted hepatic lipid metabolism, leading to increased cholesterol synthesis and hepatic lipid accumulation. This study underscores the potential of PMMA to disrupt both hepatic lipid metabolism and gut microbiota composition, suggesting a novel mechanism by which PMMA exposure could contribute to metabolic disorders and liver disease.

Effects of Nanoplastics on Lipid Membranes and Vice Versa: Insights from All-Atom Molecular Dynamics Simulations

We compute the potential of mean force (PMF) between semicrystalline polyethylene (PE) nanoplastics (NPLs) and model POPC and DPPC bilayers, which approximate in vivo membranes, using atomistic simulations. Our work shows that atomistic resolution is required to characterize the NPL and lipid interactions. By analyzing the PMF, we demonstrate that the mechanical properties of membranes, rather than NPL semicrystalline morphologies, govern NPL-membrane interactions. Resistance to NPL penetration arises from the elastic energy of the membrane deformation. The flexible POPC membranes resist NPL translocation, and the brittle DPPC membranes fracture under stress. Using an elastic free energy model, we approximate effective repulsions between lipid membranes and NPLs of various sizes. Our mean first-passage time analysis shows that even small, bare NPLs cannot easily penetrate brittle lipid membranes via passive diffusion, even at high concentrations. However, eco-coronas or other mechanisms, such as endocytosis, may still facilitate the cellular uptake of NPLs and MPLs. While semicrystalline morphologies do not directly impact NPL translocation, they do influence NPL behavior within lipid membranes upon translocation. Semicrystalline NPLs remain intact within lipid membranes, whereas amorphous NPLs can dissolve into the hydrophobic core and alter the elastic properties of the membrane.

Micro-nanoplastic induced cardiovascular disease and dysfunction: a scoping review

BACKGROUND

The human bioaccumulation of micro- and nano-plastics (MNPs) is increasingly being recognised in the aetiology and pathophysiology of human disease.

OBJECTIVE

This systematic scoping review aims to provide a comprehensive investigation of studies examining the impacts of MNPs on the human cardiovascular system.

METHODS

Five databases (PubMed, SCOPUS, CINAHL, Web of Science and EMBASE) were systematically searched.

RESULTS

Forty-six articles were identified, 13 of which investigated the presence of MNPs within the human cardiovascular system, including atherosclerotic plaques, saphenous vein tissue, thrombi and venous blood. The effect of MNPs on cell lines suggest MNPs are cytotoxic, immunotoxic, and genotoxic.

SIGNIFICANCE

The findings of this review, when evaluated together with additional studies utilising animal models, suggest MNPs may contribute to global cardiovascular morbidity and mortality. In particular, the ability of MNPs to induce endothelial damage, oxy-LDL formation, foam cell development and apoptosis, as well as to alter the clotting cascade, has potential implications for vascular diseases. In addition, MNPs may play a role in the aetiology and progression of congenital heart abnormalities, infective pathologies and cardiomyopathies. Despite an increasing awareness of the ability for MNPs to result in cardiovascular disease and dysfunction, a limited amount of research has been conducted to date characterising the presence of MNPs in the human cardiovascular system. Reseach is required to understand the extent of this rapidly emerging issue and to develop strategies that will support clinicians to appropriately manage and educate their patients in the future.

Pathological and biochemical effects of polyethylene microplastic exposure in hydrothermal vent crab, Xenograpsus testudinatus

Microplastic pollution significantly threatens marine ecosystems, including those with unique adaptations. This study evaluates the implications of polyethylene microplastics (PE-MPs) on the hydrothermal vent crab, Xenograpsus testudinatus. Crabs were exposed to varying fluorescent green polyethylene microspheres (FGPE) concentrations for 7 days. Histological analysis revealed severe damage to the hepatopancreas and gills at higher FGPE concentrations. Antioxidant enzyme activities (SOD, CAT, GR, GST, GPx, LPO) and gene expression (sod, cat) were assessed to evaluate oxidative stress responses. Results indicated significant upregulation of SOD and CAT activities at lower FGPE concentrations, suggesting an initial antioxidant response. However, GR and GST activities were inhibited at higher concentrations, and oxidative stress markers increased. These findings proved that PE-MPs induce molecular oxidative damage and lead to possible oxidative responses. Despite their resilience to extreme environments, HV crabs are vulnerable to pollutant-induced stressors, which pose ecological risks to species interactions and population dynamics within vent ecosystems.

Polystyrene nanoplastics trigger ferroptosis in Nrf2-deficient gut via ether phospholipid accumulation

The widespread environmental presence of nanoplastics (NPs) raises significant concerns about their health impacts, particularly on the gastrointestinal system, as NPs are primarily ingested. While previous studies have linked NP-induced intestinal toxicity to oxidative stress and reactive oxygen species (ROS) accumulation, the specific mechanisms of cell death remain unclear. Here, we showed that environmentally relevant concentrations of polystyrene nanoplastics (PS-NPs) induced ferroptosis, a form of lipid peroxidation-driven cell death, in intestinal epithelial cells. Using intestinal epithelial-specific Nrf2-deficient mice (Nrf2fl/fl-VilCre+) and human intestinal epithelial Caco-2 cells, we demonstrated that Nrf2, a key oxidative stress regulator, play a protective role against PS-NP-induced ferroptosis. PS-NP exposure disrupted ether phospholipid metabolism, leading to the accumulation of polyunsaturated fatty acid-ether phospholipids and heightened lipid peroxidation in the intestines of Nrf2fl/fl-VilCre+ mice. This accumulation increased the susceptibility of intestinal epithelial cells to ferroptosis. Additionally, a high-fat diet further exacerbated this effect, suggesting that individuals with reduced NRF2 activity and poor dietary habits may be especially vulnerable to PS-NP-induced intestinal damage. Our findings offered new insights into the molecular mechanisms of NP-induced intestinal toxicity and underscored the health risks posed by environmental PS-NP exposure, particularly in populations with compromised antioxidant defenses.

The Effects of Microplastics on Musculoskeletal Disorder; A Narrative Review

PURPOSE OF REVIEW

The physical health impacts of microplastics have received increasing attention in recent years. However, limited data impedes a full understanding of the internal exposure to microplastics, especially concerning the musculoskeletal system. The purpose of this review is to summarize the recent literature regarding the effects of microplastics on the musculoskeletal system.

RECENT FINDINGS

Microplastics have been shown to cause abnormal endochondral ossification and disrupt the normal function of pre-osteoblasts, osteocyte-like cells, and pre-osteoclasts through gene mutations, endoplasmic reticulum stress induction, and reduced autophagosome formation in bone growth areas. Although there are few reports on their effects on muscle, it has been noted that microplastics inhibit energy and lipid metabolism, decrease type I muscle fiber density, impair muscle angiogenesis, cause muscle atrophy, and increase lipid deposition. Only a few recent studies have shown that microplastics interfere with the normal function of bone growth-related cells and reduce muscle mass and quality. This review underscores the need for further research into other parts of the musculoskeletal system and studies using human tissues at the disease level.

Biotransport and toxic effects of micro- and nanoplastics in fish model and their potential risk to humans: A review

The growing body of scientific evidence suggests that micro- and nanoplastics (MPs/NPs) pose a significant threat to aquatic ecosystems and human health. These particles can enter organisms through ingestion, inhalation, dermal contact, and trophic transfer. Exposure can directly affect multiple organs and systems (respiratory, digestive, neurological, reproductive, urinary, cardiovascular) and activate extensive intracellular signaling, inducing cytotoxicity involving mechanisms such as membrane disruption, extracellular polymer degradation, reactive oxygen species (ROS) production, DNA damage, cellular pore blockage, lysosomal instability, and mitochondrial depolarization. This review focuses on current research examining the in vivo and in vitro toxic effects of MPs/NPs on aquatic organisms, particularly fish, in relation to particulate toxicity aspects (such as particle transport mechanisms and structural modifications). Meanwhile, from the perspectives of the food chain and environmental factors, it emphasizes the comprehensive threats of MPs/NPs to human health in terms of both direct and indirect toxicity. Additionally, future research needs and strategies are discussed to aid in mitigating the potential risks of particulate plastics as carriers of toxic trace elements to human health.

Short-term polystyrene nanoplastic exposure alters zebrafish male and female germline and reproductive outcomes, unveiling pollutant-impacted molecular pathways

Nanoplastics pollution is a rising environmental concern whose impacts on biodiversity and human health are far from being understood. This is particularly salient in aquatic ecosystems, where the majority of species depend on external fertilization for reproduction. Here we evaluated the effects of a short-term exposure to engineered polystyrene nanoplastics (NPs) in the zebrafish germline to further explore their impact on reproduction. To this end, zebrafish (Danio rerio) were exposed to 5 mg/L of 45 nm polystyrene (PS)-NPs via water for 96 h. We show that, in males, nanoplastics induced testicular histological alterations with abnormal sperm clustering and chromatin compaction, resulting in viable spermatozoa but with reduced motility. Moreover, in females we observed an alteration in oocyte stages frequencies during oogenesis, possibly reflecting alterations in oocyte growth. RNA-sequencing analysis in male testis links nanoplastic induced alterations in the expression of genes involved in chromatin structure, meiosis and DNA double-strand break formation and repair progression, and gametes recognition. Flow cytometry analysis revealed that the observed effects in males were directly due to nanoplastics penetrating the testicular barrier and being internalized within germline cells. Overall, our results demonstrate that acute exposure to NPs can compromise reproductive fitness, underscoring the environmental and health impacts of NPs pollution.

New Insights in Microplastic Cellular Uptake Through a Cell-Based Organotypic Rainbow-Trout (Oncorhynchus mykiss) Intestinal Platform

Microplastics (MPs) in fish can cross the intestinal barrier and are often bioaccumulated in several tissues, causing adverse effects. While the impacts of MPs on fish are well documented, the mechanisms of their cellular internalization remain unclear. A rainbow-trout (Oncorhynchus mykiss) intestinal platform, comprising proximal and distal intestinal epithelial cells cultured on an Alvetex scaffold, was exposed to 50 mg/L of MPs (size 1-5 µm) for 2, 4, and 6 h. MP uptake was faster in RTpi-MI compared to RTdi-MI. Exposure to microplastics compromised the cellular barrier integrity by disrupting the tight-junction protein zonula occludens-1, inducing significant decreases in the transepithelial-electrical-resistance (TEER) values. Consequently, MPs were internalized by cultured epithelial cells and fibroblasts. The expression of genes related to endocytosis (cltca, cav1), macropinocytosis (rac1), and tight junctions' formation (oclna, cldn3a, ZO-1) was analyzed. No significant differences were observed in cltca, oclna, and cldn3a expression, while an upregulation of cav1, rac1, and ZO-1 genes was detected, suggesting macropinocytosis as the route of internalization, since also cav1 and ZO-1 are indirectly related to this mechanism. The obtained results are consistent with data previously reported in vivo, confirming its validity for identifying MP internalization pathways. This could help to develop strategies to mitigate MP absorption through ingestion.

Environmental toxicology of microplastic particles on fish: A review

The increase in plastic debris and its environmental impact has been a major concern for scientists. Physical destruction, chemical reactions, and microbial activity can degrade plastic waste into particles smaller than 5 mm, known as microplastics (MPs). MPs may eventually enter aquatic ecosystems through surface runoff. The accumulation of MPs in aquatic environments poses a potential threat to finfish, shellfish, and the ecological balance. This study investigated the effect of MP exposure on freshwater and marine fish. MPs could cause significant harm to fish, including physical damage, death, inflammation, oxidative stress, disruption of cell signalling and cellular biochemical processes, immune system suppression, genetic damage, and reduction in fish growth and reproduction rates. The activation of the detoxification system of fish exposed to MPs may be associated with the toxicity of MPs and chemical additives to plastic polymers. Furthermore, MPs can enhance the bioavailability of other xenobiotics, allowing these harmful substances to more easily enter and accumulate in fish. Accumulation of MPs and associated chemicals in fish can have adverse effects on the fish and humans who consume them, with these toxic substances magnifying as they move up the food chain. Changes in migration and reproduction patterns and disruptions in predator-prey relationships in fish exposed to MPs can significantly affect ecological dynamics. These interconnected changes can lead to cascading effects throughout aquatic ecosystems. Thus, implementing solutions like reducing plastic production, enhancing recycling efforts, using biodegradable materials, and improving waste management is essential to minimize plastic waste and its environmental impact.

Microplastics: Omnipresent and an ongoing challenge for medical science

Micro- and nanoplastics are omnipresent not only in the environment, but have also been detected in human body fluids and tissue. The subsequent commentary provides a perspective about potential risks for human health as well as resulting challenges for medical science.

Microplastics - A Growing Concern as Carcinogens in Cancer Etiology: Emphasis on Biochemical and Molecular Mechanisms

In today's world, the widespread presence of microplastics is undeniable, with concentrations found in various environments, including up to 1000 particles per liter in seawater and up to 10 particles per cubic meter in the atmosphere. Originating from diverse sources, both intentional and unintentional, these minuscule fragments, measuring less than 5 mm, pose significant threats to environmental and human health. Recent research has uncovered a concerning link between microplastics and cancer, prompting urgent investigation. Studies demonstrate microplastics can infiltrate cells, disrupt biological processes, and potentially foster carcinogenic environments. From inducing DNA damage and oxidative stress to triggering inflammatory responses and dysregulating cellular pathways, microplastics exhibit a multifaceted capability in contributing to cancer development. Furthermore, microplastics act as carriers for a range of contaminants, compounding their impact on human health. Their accumulation within tissues and organs raises concerns for short and long-term health consequences, including chronic diseases, reproductive issues, and developmental abnormalities. This review explores the biochemical and molecular mechanisms underlying the interaction between microplastics and cellular systems, providing insights into routes of exposure and health effects, with a focus on lung, skin, and digestive system cancers. As we confront this pressing environmental and public health challenge, a deeper understanding of the microplastic-cancer relationship is crucial to safeguarding the well-being of present and future generations.

Quantifying the effects of chlorine disinfection on microplastics by time-resolved inductively coupled plasma-mass spectrometry

Using current water treatment systems, significant amounts of microplastics (MPs) are passing through and being released into the aquatic environment. However, we do not clearly know what effects disinfection processes have had on these particles. In this study, we applied inductively coupled plasma-mass spectrometry (ICP-MS) operating in time-resolved analysis (TRA) mode for quantifying changes in the chlorine (Cl) content of MPs under a variety of water treatment scenarios. Our results illustrated that time-resolved ICP-MS offers a potential method for sensitive and direct analysis of Cl content, including Cl mass and chlorine association (%Cl/C), of discrete particles in the MP suspension by the fast sequential measurements of signals from 35Cl1H2 and 12C1H. Our research, across various water treatment scenarios, also showed that polystyrene (PS) MPs exhibited greater reactivity to Cl disinfectant after being pre-disinfected with UV light and in mildly acidic to neutral pH environments. It is noteworthy that about half of the particles in MP suspension exposed to 10 mg Cl2/L, a typical Cl dose applied in water treatment, were chlorinated, and had a Cl content comparable to that of particles subjected to extreme conditions. Of even greater concern is the fact that our cell viability tests revealed that chlorinated MPs induced considerably higher rates of cell death in both human A549 and Caco-2 cells, and that the effects were Cl dose- and polymer type-dependent. Overall, this study demonstrates the potential of time-resolved ICP-MS as a valuable technique for quantifying the Cl content of MP particles, which is crucial to assessing the fate and transformation of MPs in our water supply and treatment systems.

Local and systemic effects of microplastic particles through cell damage, release of chemicals and drugs, dysbiosis, and interference with the absorption of nutrients

Microplastic particles (MPs) have been detected in a variety of environmental samples, including soil, water, food, and air. Cellular studies and animal exposures reported that exposure to MPs composed of different polymers might result in adverse effects at the portal of entry (local) or throughout the body (systemic). The most relevant routes of particle uptake into the body are oral and respiratory exposure. This review describes the various processes that may contribute to the adverse effects of MPs. Only MPs up to 5 µm were found to cross epithelial barriers to a significant extent. However, MPs may also exert a detrimental impact on human health by acting at the epithelial barrier and within the lumen of the orogastrointestinal and respiratory tract. The potential for adverse effects on human health resulting from the leaching, sorption, and desorption of chemicals, as well as the impact of MPs on nutritional status and dysbiosis, are reviewed. In vitro models are suggested as a means of (1) assessing permeation, (2) determining adverse effects on cells of the epithelial barrier, (3) examining influence of digestive fluids on leaching, desorption, and particle properties, and (4) role of microbiota-epithelial cell interactions. The contribution of these mechanisms to human health depends upon exposure levels, which unfortunately have been estimated very differently.

Upconversion Phosphor-Driven Photodegradation of Plastics

Plastic waste poses a profound threat to ecosystems and human health, necessitating novel strategies for effective degradation in nature. Here, we present a novel approach utilizing upconversion phosphors as additives to significantly accelerate plastic photodegradation in nature via enhancing ultraviolet (UV) radiation. Pr-doped Li2CaGeO4 (LCGO:Pr) upconversion phosphors readily converting blue light into deep-UV radiation, dramatically improve photodegradation rates for polyethylene (PE) and polyethylene terephthalate (PET) microplastics. In situ spectroscopic studies show that upconversion fluorescence initiates the photophysical cleavage of C-C and C-O bonds in the backbones of PE and PET, resulting in plastic degradation. Moreover, incorporating LCGO:Pr into polypropylene (PP) sheets realizes markedly enhanced photodamage, with the cracking area increasing by nearly 38-fold under simulated sunlight for 10 days. This underscores the potential of employing this approach for the construction of light-driven destructible polymers. Further optimization and exploration of material compatibility hold promise for developing sustainable photodegradable plastics.

Adverse effects of environmentally relevant concentration of microplastics on gill epithelium permeability in the euryhaline Mediterranean killifish Aphanius fasciatus

Estuaries and lagoons are characterized by fluctuating salinity and significant amounts of microplastics (MPs) and are increasingly subjected to various anthropogenic pressures. We investigated whether the accumulation of MPs in the gills of fish inhabiting these fragile ecosystems alters osmoregulation and, consequently, their ability to tolerate fluctuating salinity. The effects of a 15-day exposure to an environmentally relevant concentration (20 μg/L) of spherical polystyrene microplastics (PS-MPs) with a diameter of 5 μm were assessed in the Mediterranean killifish Aphanius fasciatus, focusing on tissue and gene expression changes related to factors of paracellular and transcellular permeability of the gill epithelium during the transition from seawater to freshwater. Our results revealed that PS-MPs indirectly impaired osmoregulation, particularly in fresh water, through their toxic effects on the gill tissue. Toxicity was evidenced by epithelial lifting, a decrease in the proportion of secondary lamellae available for gas exchange, and upregulation of superoxide dismutase and heat shock protein genes. Furthermore, exposure to PS-MPs directly affected gill epithelial permeability by maintaining relatively high paracellular permeability through the downregulation of claudin 3 and by modifying the expression of the transcellular transporter Na+/K+-ATPase and cystic fibrosis transmembrane conductance regulator in the gill epithelium. Overall, these findings confirm the toxic effects of PS-MPs on gill tissue and demonstrate, for the first time, that environmentally relevant concentrations of MPs adversely affect gill epithelium permeability during decreased salinity acclimation in the euryhaline fish A. fasciatus.

Machine learning-driven QSAR models for predicting the cytotoxicity of five common microplastics

In the field of microplastics (MPs) toxicity prediction, machine learning (ML) computer simulation techniques are showing great potential. In this study, six ML algorithms were utilized to predict the toxicity of MPs on BEAS-2B cells based on quantitative structure-activity relationship (QSAR) models. Comparing the models of different algorithms, the extreme gradient boosting model showed the best fit and prediction performance (R2tra = 0.9876, R2test = 0.9286). Additionally, Williams plot analysis showed that the six models developed were able to predict stably within their applicability domain, with few outliers. Finally, the three feature importance methods-Embedded Feature Importance (EFI), Recursive Feature Elimination (RFE), and SHapley Additive exPlanations (SHAP)-consistently identified particle size as the most critical feature affecting toxicity prediction. The proposed QSAR model can be utilized for preliminary environmental exposure assessments of MPs and to better understand the associated health risks.

Aging affects the mechanical interaction between microplastics and lipid bilayers

Plastic pellets, the pre-production form of many plastic products, undergo oxidation and photodegradation upon exposure to oxygen and sunlight, resulting in visible color changes. This study examines the impact of environmental aging on the mechanical interactions between pellet-derived microplastics and lipid bilayers, a critical component of biological membranes. Polyethylene pellets were collected from La Pineda beach near Tarragona, Spain, and categorized by chemical composition and yellowing index, an indicator of aging. The hydrophilicity of these pellets was assessed using contact angle measurements. Microplastics were produced by grinding and filtering these pellets and subsequently dispersed around a free-standing lipid bilayer within a 3D microfluidic chip to investigate their interactions. Our results reveal that aged microplastics exhibit a significantly increased adhesive interaction with lipid bilayers, leading to greater bilayer stretching. Theoretical modeling indicates a linear relationship between the adhesive interaction and the contact angle of the pellets, reflecting their hydrophilicity. These findings emphasize the increased mechanical impact of aged microplastics on biological membranes, which raises concerns about their potential toxicological effects on living organisms. This study highlights the importance of understanding the interactions between environmentally aged microplastics and biological systems to assess their risks, as these may differ significantly from pristine microplastics often studied under laboratory conditions.

Microplastics in the human body: A comprehensive review of exposure, distribution, migration mechanisms, and toxicity

Microplastics (MPs) are pervasive across ecosystems, presenting substantial risks to human health. Developing a comprehensive review of MPs is crucial due to the growing evidence of their widespread presence and potential harmful effects. Despite the growth in research, considerable uncertainties persist regarding their transport dynamics, prevalence, toxicological impacts, and the potential long-term health effects they may cause. This review thoroughly evaluates recent advancements in research on MPs and their implications for human health, including estimations of human exposure through ingestion, inhalation, and skin contact. It also quantifies the distribution and accumulation of MPs in various organs and tissues. The review discusses the mechanisms enabling MPs to cross biological barriers and the role of particle size in their translocation. To ensure methodological rigor, this review adheres to the PRISMA guidelines, explicitly detailing the literature search strategy, inclusion criteria, and the quality assessment of selected studies. The review concludes that MPs pose significant toxicological risks, identifies critical gaps in current knowledge, and recommends future research directions to elucidate the prolonged effects of MPs on human health. This work aims to offer a scientific framework for mitigating MP-related hazards and establishes a foundation for ongoing investigation.

New Insights into the Mechanisms of Toxicity of Aging Microplastics

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes-methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs.

Hydrogen bonding-mediated interaction underlies the enhanced membrane toxicity of chemically transformed polystyrene microplastics by cadmium

The global attention on microplastic pollution and its implications for human health has grown in recent years. Additionally, the co-existence of heavy metals may significantly alter microplastics' physicochemical characteristics, potentially amplifying their overall toxicity-a facet that remains less understood. In this study, we focused the membrane toxicity of modified polystyrene microplastics (PS-MPs) following cadmium (Cd) pretreatment. Our findings revealed that Cd-pretreated PS-MPs exacerbated their toxic effects, including diminished membrane integrity and altered phase fluidity in simulated lipid membrane giant unilamellar vesicles (GUVs), as well as heightened membrane permeability, protein damage, and lipid peroxidation in red blood cells and macrophages. Mechanistically, these augmented membrane toxicities can be partially ascribed to modifications in the surface roughness and hydrophilicity of Cd-pretreated PS-MPs, as well as to interactions between PS-MPs and lipid bilayers. Notably, hydrogen bonds emerged as a crucial mechanism underlying the enhanced interaction of PS-MPs with lipid bilayers.

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.

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.

Total Intravenous Anesthesia Is Preferred Over Volatile Agents in Cardiac Surgery

The choice of maintenance anesthetic during cardiopulmonary bypass has been a subject of ongoing debate. Systematic reviews on the topic have so far failed to demonstrate a difference between volatile agents and total intravenous anesthesia (TIVA) in terms of mortality, myocardial injury, and neurological outcomes. Studies using animal models and noncardiac surgical populations suggest numerous mechanisms whereby TIVA has been associated with more favorable outcomes. However, even if the different anesthetic methods are assumed to equivalent in terms of patient outcomes in the context of cardiac surgery, additional factors, namely variables of occupational exposure and environmental impact, strongly support the preferred use of TIVA.

Synergistic Effects of Microplastics and Marine Pollutants on the Destabilization of Lipid Bilayers

Microplastics have been detected in diverse environments, including soil, snowcapped mountains, and even within human organs and blood. These findings have sparked extensive research into the health implications of microplastics for living organisms. Recent studies have shown that microplastics can adsorb onto lipid membranes and induce mechanical stress. In controlled laboratory conditions, the behavior and effects of microplastics can differ markedly from those in natural environments. In this study, we investigate how exposure of microplastics to pollutants affects their interactions with lipid bilayers. Our findings reveal that pollutants, such as chemical solvents, significantly enhance the mechanical stretching effects of microplastics. This suggests that microplastics can act as vectors for harmful pollutants, facilitating their penetration through lipid membranes and thus strongly affect their biophysical properties. This research underscores the complex interplay between microplastics and environmental contaminants.

Photoaging of polystyrene-based microplastics amplifies inflammatory response in macrophages

The continuous release of municipal and industrial products into the environment poses a growing concern for public health. Among environmental pollutants, polystyrene (PS) stands out as a primary constituent of environmental plastic waste, given its widespread use and high production rates owing to its durability and user-friendly properties. The detection of polystyrene microparticles (PS-MPs) in various living organisms has been well-documented, posing a serious threat due to their potential passage into the human ecosystem. In this manuscript, we aimed to study the toxicological effects of low concentrations of pristine and photoaged PS-MPs in a murine macrophage cell line. To this purpose, PS-MPs were photoaged by indoor exposure to visible light to simulate environmental weathering due to solar irradiation (PS-MPs3h). Physical characterization revealed that the irradiation treatment results in particle degradation and the possible release of nanoparticles. Monocultures of the RAW264.7 cell line were then exposed to PS-MPs and PS-MPs3h at concentrations comparable to experimental measurements from biological samples, to assess cytotoxicity, intracellular oxidative stress, primary genotoxicity, and inflammatory effects. Significant toxicity-related outcomes were observed in cells treated with both pristine PS-MPs and PS-MPs3h even at low concentrations (0,10 μg/ml and 1 μg/ml). PS-MPs3h exhibited greater adverse effects compared to PS-MPs, including reduced cell viability, increased ROS production, elevated DNA damage, and upregulation of IL-6 and NOS2 gene expression. Therefore, we can conclude that changes induced by environmental aging in the physicochemical composition of PS microplastics play a crucial role in the adverse health outcomes associated with microplastic exposure.

Plastic induced urinary tract disease and dysfunction: a scoping review

INTRODUCTION

In 2019 the World Health Organisation published a report which concluded microplastics in drinking water did not present a threat to human health. Since this time a plethora of research has emerged demonstrating the presence of plastic in various organ systems and their deleterious pathophysiological effects.

METHODS

A scoping review was undertaken in line with recommendations from the Johanna Briggs Institute. Five databases (PubMed, SCOPUS, CINAHL, Web of Science and EMBASE) were systematically searched in addition to a further grey literature search.

RESULTS

Eighteen articles were identified, six of which investigated and characterised the presence of microplastics and nanoplastics (MNPs) in the human urinary tract. Microplastics were found to be present in kidney, urine and bladder cancer samples. Twelve articles investigated the effect of MNPs on human cell lines associated with the human urinary tract. These articles suggest MNPs have a cytotoxic effect, increase inflammation, decrease cell viability and alter mitogen-activated protein kinases (MAPK) signalling pathways.

CONCLUSION

Given the reported presence MNPs in human tissues and organs, these plastics may have potential health implications in bladder disease and dysfunction. As a result, institutions such as the World Health Organisation need to urgently re-evaluate their position on the threat of microplastics to public health.

IMPACT STATEMENT

This scoping review highlights the rapidly emerging threat of microplastic contamination within the human urinary tract, challenging the World Health Organisation's assertion that microplastics pose no risk to public health. The documented cytotoxic effects of microplastics, alongside their ability to induce inflammation, reduce cell viability and disrupt signalling pathways, raise significant public health concerns relating to bladder cancer, chronic kidney disease, chronic urinary tract infections and incontinence. As a result, this study emphasises the pressing need for further research and policy development to address the challenges surrounding microplastic contamination.

Size-dependent effects of microplastics on intestinal microbiome for Perna viridis

Microplastics pollution threatens to marine organisms, particularly bivalves that actively ingest and accumulate microplastics of certain sizes, potentially disrupting intestinal homeostasis. This study investigated the microplastic abundance in wild and farmed mussels around Singapore, and examined the size-dependent effects of nano- to micro-scale polystyrene (0.5 µm/5 µm/50 µm) on the mussel intestinal microbiome in the laboratory. The field investigation revealed higher microplastic abundance in farmed mussels compared to wild ones. Experimentally, mussels exposed to 0.6 mg/L of microplastics for 7 days, followed by a 7-day depuration period, showed substantial impacts on Spirochaetes and Proteobacteria, facilitating the proliferation of pathogenic species and differentially affecting their pathogenic contributions. Metagenomics analysis revealed that microplastic exposure reduced Spirochaeta's contribution to virulence and pathogenicity loss, did not affect Vibrio and Oceanispirochaeta's pathogenicity, and increased Treponema and Oceanispirochaeta's contributions to pathogenicity loss. Moreover, microplastics increased transmembrane transporters and impacted oxidative phosphorylation enzymes, impairing energy metabolism. These effects persisted after depuration, indicating lack of resilience in the microbiome. Nano- and micro-scale plastics perturbed the mussel microbiome composition and functions in a size-dependent manner, with nano-plastics being the most disruptive. The increasing use and sale of aquaculture equipment of plastic may exacerbate the intestinal dysbiosis in bivalves, which threatens consumers' health.

Microplastics promote methane emission in estuarine and coastal wetlands

Increasing microplastic (MP) pollution poses significant threats to estuarine and coastal ecosystems. However, the effects of MPs on the emission of methane (CH4), a potent greenhouse gas, within these ecosystems and the underlying regulatory mechanisms have not been elucidated. Here, a combination of 13C stable isotope-based method and molecular techniques was applied to investigate how conventional petroleum-based MPs [polyethylene (PE) and polyvinyl chloride (PVC)] and biodegradable MPs [polylactic acid (PLA) and polyadipate/butylene terephthalate (PBAT)] regulate CH4 production and consumption and thus affect CH4 emission dynamics in estuarine and coastal wetlands. Results indicated that both conventional and biodegradable MPs enhanced the emission of CH4 (P < 0.05), with the promoting effect being more significant for biodegradable MPs. However, the mechanisms by which conventional and biodegradable MPs promote CH4 emissions were different. Specifically, conventional MPs stimulated the emission of CH4 by inhibiting the processes of CH4 consumption, but had no significant effect on CH4 production rate. Nevertheless, biodegradable MPs promoted CH4 emissions via accelerating the activities the methanogens while inhibiting the oxidation of CH4, thus resulting in a higher degree of promoting effect on CH4 emissions than conventional MPs. Consistently, quantitative PCR further revealed a significant increase in the abundance of methyl-coenzyme M reductase gene (mcrA) of methanogens under the exposure of biodegradable MPs (P < 0.05), but not conventional MPs. Furthermore, the relative abundance of most genes involved in CH4 oxidation exhibited varying degrees of reduction after exposure to all types of MPs, based on metagenomics data. This study reveals the effects of MPs on CH4 emissions in estuarine and coastal ecosystems and their underlying mechanisms, highlighting that the emerging biodegradable MPs exhibited a greater impact than conventional MPs on promoting CH4 emissions in these globally important ecosystems, thereby accelerating global climate change.

Multigenerational resilience of the marine rotifer Brachionus plicatilis to high temperature after additive exposure to high salinity and nanoplastics

To study multigenerational resilience to high temperature (HT) conditions, we exposed Brachionus plicatilis marine rotifers to HT, high salinity (HS), and nanoplastics (NPs), and measured reproductive and life-cycle endpoints. After exposure to HT, rotifer lifespans were reduced, but daily production of offspring increased. However, both combined HT/HS and HT/HS/NP exposure led to additional decreases in longevity and reproductive ability; the antioxidant defense mechanisms of the rotifers were also notably upregulated as measured by reactive oxygen species levels. Fatty-acid profiles were reduced in all conditions. In multigenerational experiments, the negative effects of HT dissipated rapidly; however, the effects of HT/HS and HT/HS/NPs required four generations to disappear completely. The findings indicated that B. plicatilis were able to recover from these environmental stressors. This study demonstrated the resilience of aquatic organisms in response to changing environmental conditions and provides insights into the complex interactions of different abiotic stressors.

Ecotoxicity evaluation using the avoidance response of the oribatid mite Oppia nitens (Acari: Oribatida) in bioplastics, microplastics, and contaminated Superfund field sites

Bioplastics are considered sustainable alternatives to conventional microplastics which are recognized as a threat to terrestrial ecosystems. However, little is known about the potential ecotoxicological effects of bioplastics on soil fauna and ecosystems. The present study assessed the toxicity of microplastics [Polystyrene (PS), Polyethylene (PE)] and bioplastics [Polyvinyl alcohol (PVA), Sodium polyacrylate (NaPa) on a key soil fauna Oppia nitens, a soil oribatid mite, and investigated the ecological relevance of O. nitens avoidance response as a valuable tool for the risk assessment of contaminated soils such as the Superfund sites. Findings showed that the mites' net response indicated avoidance behavior such that in most cases as concentrations of micro- and bioplastics increased, so did the avoidance responses. The avoidance EC50 endpoints showed PS < PE < PVA < NaPa, indicating higher deleterious effects of microplastics. High toxicity of PS in soils to O. nitens at EC50 of 165 (±25) mg/kg compared to bioplastics and other known contaminants poses an enormous threat to soil. For bioplastics in this study, there were no significant avoidances at concentrations up to 16,200 mg/kg compared to PS and PE which showed avoidance responses at 300 and 9000 mg/kg respectively, implying that bioplastics might be relatively safer to soil mites compared to conventional microplastics. Also, results indicated that long-term heavy metal pollution such as in contaminated Superfund sites decreased microbial biomass; a useful bioindicator of soil pollution. Furthermore, O. nitens avoidance of heavy metals contaminated sites demonstrated the ecological relevance of avoidance response test when assessing the habitat integrity of contaminated soil. The present study further supports the inclusion of the oribatid mite, O. nitens in the ecological risk assessment of contaminants in soil.

The Impact of Virgin and Aged Microstructured Plastics on Proteins: The Case of Hemoglobin Adsorption and Oxygenation

Plastic particles, particularly micro- and nanoparticles, are emerging pollutants due to the ever-growing amount of plastics produced across a wide variety of sectors. When plastic particles enter a biological medium, they become surrounded by a corona, giving them their biological identity and determining their interactions in the living environment and their biological effects. Here, we studied the interactions of microstructured plastics with hemoglobin (Hb). Virgin polyethylene microparticles (PEMPs) and polypropylene microparticles (PPMPs) as well as heat- or irradiation-aged microparticles (ag-PEMPs and ag-PPMPs) were used to quantify Hb adsorption. Polypropylene filters (PP-filters) were used to measure the oxygenation of adsorbed Hb. Microstructured plastics were characterized using optical microscopy, SAXS, ATR-FTIR, XPS, and Raman spectroscopy. Adsorption isotherms showed that the Hb corona thickness is larger on PPMPs than on PEMPs and Hb has a higher affinity for PPMPs than for PEMPs. Hb had a lower affinity for ag-PEMPs and ag-PPMPs, but they can be adsorbed in larger amounts. The presence of partial charges on the plastic surface and the oxidation rate of microplastics may explain these differences. Tonometry experiments using an original method, the diffuse reflection of light, showed that adsorbed Hb on PP-filters retains its cooperativity, but its affinity for O2 decreases significantly.

Probiotics an emerging therapeutic approach towards gut-brain-axis oriented chronic health issues induced by microplastics: A comprehensive review

Applications for plastic polymers can be found all around the world, often discarded without any prior care, exacerbating the environmental issue. When large waste materials are released into the environment, they undergo physical, biological, and photo-degradation processes that break them down into smaller polymer fragments known as microplastics (MPs). The time it takes for residual plastic to degrade depends on the type of polymer and environmental factors, with some taking as long as 600 years or more. Due to their small size, microplastics can contaminate food and enter the human body through food chains and webs, causing gastrointestinal (GI) tract pain that can range from local to systemic. Microplastics can also acquire hydrophobic organic pollutants and heavy metals on their surface, due to their large surface area and surface hydrophobicity. The levels of contamination on the microplastic surface are significantly higher than in the natural environment. The gut-brain axis (GB axis), through which organisms interact with their environment, regulate nutritional digestion and absorption, intestinal motility and secretion, complex polysaccharide breakdown, and maintain intestinal integrity, can be altered by microplastics acting alone or in combination with pollutants. Probiotics have shown significant therapeutic potential in managing various illnesses mediated by the gut-brain axis. They connect hormonal and biochemical pathways to promote gut and brain health, making them a promising therapy option for a variety of GB axis-mediated illnesses. Additionally, taking probiotics with or without food can reduce the production of pro-inflammatory cytokines, reactive oxygen species (ROS), neuro-inflammation, neurodegeneration, protein folding, and both motor and non-motor symptoms in individuals with Parkinson's disease. This study provides new insight into microplastic-induced gut dysbiosis, its associated health risks, and the benefits of using both traditional and next-generation probiotics to maintain gut homeostasis.

Research progress on the regulatory role of cell membrane surface tension in cell behavior

Cell membrane surface tension has emerged as a pivotal biophysical factor governing cell behavior and fate. This review systematically delineates recent advances in techniques for cell membrane surface tension quantification, mechanosensing mechanisms, and regulatory roles of cell membrane surface tension in modulating major cellular processes. Micropipette aspiration, tether pulling, and newly developed fluorescent probes enable the measurement of cell membrane surface tension with spatiotemporal precision. Cells perceive cell membrane surface tension via conduits including mechanosensitive ion channels, curvature-sensing proteins (e.g. BAR domain proteins), and cortex-membrane attachment proteins (e.g. ERM proteins). Through membrane receptors like integrins, cells convert mechanical cues into biochemical signals. This conversion triggers cytoskeletal remodeling and extracellular matrix interactions in response to environmental changes. Elevated cell membrane surface tension suppresses cell spreading, migration, and endocytosis while facilitating exocytosis. Moreover, reduced cell membrane surface tension promotes embryonic stem cell differentiation and cancer cell invasion, underscoring cell membrane surface tension as a regulator of cell plasticity. Outstanding questions remain regarding cell membrane surface tension regulatory mechanisms and roles in tissue development/disease in vivo. Emerging tools to manipulate cell membrane surface tension with high spatiotemporal control in combination with omics approaches will facilitate the elucidation of cell membrane surface tension-mediated effects on signaling networks across various cell types/states. This will accelerate the development of cell membrane surface tension-based biomarkers and therapeutics for regenerative medicine and cancer. Overall, this review provides critical insights into cell membrane surface tension as a potent orchestrator of cell function, with broader impacts across mechanobiology.

Microplastics and Oxidative Stress-Current Problems and Prospects

Microplastics (MPs) are plastic particles between 0.1 and 5000 µm in size that have attracted considerable attention from the scientific community and the general public, as they threaten the environment. Microplastics contribute to various harmful effects, including lipid peroxidation, DNA damage, activation of mitogen-activated protein kinase pathways, cell membrane breakages, mitochondrial dysfunction, lysosomal defects, inflammation, and apoptosis. They affect cells, tissues, organs, and overall health, potentially contributing to conditions like cancer and cardiovascular disease. They pose a significant danger due to their widespread occurrence in food. In recent years, information has emerged indicating that MPs can cause oxidative stress (OS), a known factor in accelerating the aging of organisms. This comprehensive evaluation exposed notable variability in the reported connection between MPs and OS. This work aims to provide a critical review of whether the harmfulness of plastic particles that constitute environmental contaminants may result from OS through a comprehensive analysis of recent research and existing scientific literature, as well as an assessment of the characteristics of MPs causing OS. Additionally, the article covers the analytical methodology used in this field. The conclusions of this review point to the necessity for further research into the effects of MPs on OS.

ELM combined with differential Raman spectroscopy for the detection of microplastics in organisms

Aiming at the problems of low extraction efficiency, high false detection rate, weak Raman signal and serious interference by fluorescence signal in the detection of microplastics in marine organisms, this paper establishes a set of rapid detection methods for microplastics in organisms, including confocal Raman spectroscopy, fluorescence imaging, differential Raman spectroscopy, and rapid identification of microplastics based on the ELM modeling assistance. Firstly, to address the problem of low extraction efficiency of microplastics, we explored and optimized the digestion method of tissues, which effectively improved the digestion effect of fish tissues and excluded the influence of tissues on microplastics detection. Aiming at the problems of high misdetection rate and low pre-screening efficiency of microplastics, fluorescence imaging technology is adopted to realize the visualization and detection of microplastics, which effectively improves the detection efficiency and precision of microplastics. Based on the confocal microscopy Raman spectroscopy detection system built independently in the laboratory, using 784/785 nm as the excitation light, the differential Raman spectroscopy technique effectively excludes the interference of fluorescence signals in the Raman spectra, and improves the signal-to-noise ratio of the Raman spectra, and the recovery rate of the Raman characteristic peaks in the differential Raman spectroscopy reaches 100 % compared to the traditional baseline correction method, which is 33.3 % higher than that of the baseline correction method. Finally, a microplastic identification model is constructed based on ELM to assist in realizing the rapid and accurate identification of microplastics. The more complete detection method of microplastics in marine organisms proposed in this paper can realize the rapid and nondestructive, efficient and accurate detection of microplastics in fish, which can help to further promote the development of marine microplastics monitoring technology.

Nanoplastic contamination: Impact on zebrafish liver metabolism and implications for aquatic environmental health

Nanoplastics (NPs) are increasingly pervasive in the environment, raising concerns about their potential health implications, particularly within aquatic ecosystems. This study investigated the impact of polystyrene nanoparticles (PSN) on zebrafish liver metabolism using liquid chromatography hybrid quadrupole time of flight mass spectrometry (LC-QTOF-MS) based non-targeted metabolomics. Zebrafish were exposed to 50 nm PSN for 28 days at low (L-PSN) and high (H-PSN) concentrations (0.1 and 10 mg/L, respectively) via water. The results revealed significant alterations in key metabolic pathways in low and high exposure groups. The liver metabolites showed different metabolic responses with L-PSN and H-PSN. A total of 2078 metabolite features were identified from the raw data obtained in both positive and negative ion modes, with 190 metabolites deemed statistically significant in both L-PSN and H-PSN groups. Disruptions in lipid metabolism, inflammation, oxidative stress, DNA damage, and amino acid synthesis were identified. Notably, L-PSN exposure induced changes in DNA building blocks, membrane-associated biomarkers, and immune-related metabolites, while H-PSN exposure was associated with oxidative stress, altered antioxidant metabolites, and liver injury. For the first time, L-PSN was found depolymerized in the liver by cytochrome P450 enzymes. Utilizing an analytical approach to the adverse outcome pathway (AOP), impaired lipid metabolism and oxidative stress have been identified as potentially conserved key events (KEs) associated with PSN exposure. These KEs further induced liver inflammation, steatosis, and fibrosis at the tissue and organ level. Ultimately, this could significantly impact biological health. The study highlights the PSN-induced effects on zebrafish liver metabolism, emphasizing the need for a better understanding of the risks associated with NPs contamination in aquatic ecosystems.

Nano-scale and micron-scale plastics amplify the bioaccumulation of benzophenone-3 and ciprofloxacin, as well as their co-exposure effect on disturbing the antioxidant defense system in mussels, Perna viridis

Plastics ranging from nano-scale to micron-scale are frequently ingested by many marine animals. These particles exhibit biotoxicity and additionally perform as vectors that convey and amass adsorbed chemicals within organisms. Meanwhile, the frequency of detection of the benzophenone-3 and ciprofloxacin can be adsorbed on plastic particles, then accumulated in bivalves, causing biotoxicity. To understand their unknown accumulative kinetics in vivo affected by different plastic sizes and toxic effect from co-exposure, several scenarios were set up in which the mode organism were exposed to 0.6 mg/L of polystyrene carrying benzophenone-3 and ciprofloxacin in three sizes (300 nm, 38 μm, and 0.6 mm). The live Asian green mussels were chosen as mode organism for exposure experiments, in which they were exposed to environments with plastics of different sizes laden with benzophenone-3 and ciprofloxacin, then depurated for 7 days. The bioaccumulation and depuration kinetics of benzophenone-3 and ciprofloxacin were measured using HPLC-MS/MS after one week of exposure and depuration. Meanwhile, their toxic effect were investigated by measuring the changes in six biomarkers (condition index, reactive oxygen species, catalase, glutathione, lipid peroxidation, cytochrome P450 and DNA damage). The bioconcentration factors in mussels under different exposure conditions were 41.48-111.75 for benzophenone-3 and 6.45 to 12.35 for ciprofloxacin. The results suggested that microplastics and nanoplastics can act as carriers to increase bioaccumulation and toxicity of adsorbates in mussels in a size-dependent manner. Overproduction of reactive oxygen species caused by microplastics and nanoplastics led to increased DNA damage, lipid peroxidation, and changes in antioxidant enzymes and non-enzymatic antioxidants during exposure. Marked disruption of antioxidant defenses and genotoxic effects in mussels during depuration indicated impaired recovery. Compared to micron-scale plastic with sizes over a hundred micrometers that had little effect on bivalve bioaccumulation and toxicity, nano-scale plastic greatly enhanced the biotoxicity effect.

Polystyrene microplastics enhanced the effect of PFOA on Chlorella sorokiniana: Perspective from the cellular and molecular levels

Microplastics (MPs) commonly coexist with other contaminants and alter their toxicity. Perfluorooctanoic acid (PFOA), an emerging pollutant, may interact with MPs but remain largely unknown about the joint toxicity of PFOA and MPs. Hence, this research explored the single and joint effects of PFOA and polystyrene microplastics (PS-MPs) on microalgae (Chlorella sorokiniana) at the cellular and molecular levels. Results demonstrated that PS-MPs increased PFOA bioavailability by altering cell membrane permeability, thus aggravating biotoxicity (synergistic effect). Meanwhile, the defense mechanisms (antioxidant system modulation and extracellular polymeric substances secretion) of Chlorella sorokiniana were activated to alleviate toxicity. Additionally, transcriptomic analysis illustrated that co-exposure had more differential expression genes (DEGs; 4379 DEGs) than single-exposure (PFOA: 2533 DEGs; PS-MPs: 492 DEGs), which were mainly distributed in the GO terms associated with the membrane composition and antioxidant system. The molecular regulatory network further revealed that PS-MPs and PFOA primarily regulated the response mechanisms of Chlorella sorokiniana by altering the ribosome biogenesis, photosynthesis, citrate cycle, oxidative stress, and antioxidant system (antioxidant enzyme, glutathione-ascorbate cycle). These findings elucidated that PS-MPs enhanced the effect of PFOA, providing new insights into the influences of MPs and PFOA on algae and the risk assessment of multiple contaminants. ENVIRONMENTAL IMPLICATION: MPs and PFAS, emerging contaminants, are difficult to degrade and pose a non-negligible threat to organisms. Co-pollution of MPs and PFAS is ubiquitous in the aquatic environment, while risks of co-existence to organisms remain unknown. The present study revealed the toxicity and defense mechanisms of microalgae exposure to PS-MPs and PFOA from cellular and molecular levels. According to biochemical and transcriptomic analyses, PS-MPs increased PFOA bioavailability and enhanced the effect of PFOA on Chlorella sorokiniana, showing a synergistic effect. This research provides a basis for assessing the eco-environmental risks of MPs and PFAS.

Molecular mechanism for combined toxicity of micro(nano)plastics and carbon nanofibers to freshwater microalgae Chlorella pyrenoidosa

The understanding of the environmental consequences resulting from the presence of micro(nano)plastics and carbon nanofibers (CNFs) in aquatic ecosystems is currently limited. This research endeavor sought to investigate the underlying molecular mechanisms by which engineered polystyrene-based microplastics (MPs)/nanoplastics (NPs) and CNFs, both individually and in combination, elicit toxic effects on an algal species Chlorella pyrenoidosa. The findings revealed that the combined toxicity of MPs/NPs and CNFs depended on the concentration of the mixture. As the concentration increased, the combined toxicity of MPs/NPs and CNFs was significantly greater than the toxicity of each component on its own. Furthermore, the combined toxicity of NPs and CNFs was higher than that of MPs and CNFs. The study integrated data on cell membrane integrity, oxidative stress, and antioxidant modulation to create an Integrated Biomarker Response index, which demonstrated that the co-exposure of algae to NPs and CNFs resulted in more severe cellular stress compared to exposure to NPs alone. Similarly, the combination of NPs and CNFs caused greater cellular stress than the combination of MPs and CNFs. Additionally, significant changes in the expression of stress-related genes caused by MPs/NPs alone and in combination with CNFs indicated that oxidative stress response, glucose metabolism, and energy metabolism played critical roles in particle-induced toxicity. Overall, this study provides the first insight into the toxicological mechanism of MPs/NPs and CNFs mixtures at the molecular level in freshwater microalgae.

Polystyrene Nano- and Microplastic Particles Induce an Inflammatory Gene Expression Profile in Rat Neural Stem Cell-Derived Astrocytes In Vitro

Microplastics are considered an emerging environmental pollutant due to their ubiquitous presence in the environment. However, the potential impact of microplastics on human health warrants further research. Recent studies have reported neurobehavioral and neurotoxic effects in marine and rodent models; however, their impact on the underlying cellular physiology in mammals remains unclear. Herein, we exposed neural stem cells and neural stem cell-derived astrocytes, oligodendrocytes, and neurons to various sizes and concentrations of polystyrene nano- and microplastics. We investigated their cellular uptake, impact on cytotoxicity, and alteration of gene expression through transcriptome profiling. The cell type most affected by decreased viability were astrocytes after 7 days of repeated exposure. Transcriptional analysis showed that 1274 genes were differentially expressed in astrocytes exposed to 500 nm microplastics, but only 531 genes were altered in astrocytes exposed to 50 nm nanoplastics. Both canonical pathway and Kyoto Encyclopedia of Genes and Genomes analysis showed that upregulated pathways were involved in neuroinflammation, innate and adaptive immunity, cell migration, proliferation, extracellular matrix remodeling, and cytoskeleton structures. The downregulated pathways were involved in lipid metabolism, specifically fatty acid oxidation and cholesterol metabolism. Our results show that neural stem cell-derived astrocytes repeatedly exposed to nano- and microplastics for 7 days undergo changes that are hallmarks of astrogliosis.

Intracellular Protein Adsorption Behavior and Biological Effects of Polystyrene Nanoplastics in THP-1 Cells

Micro(nano)plastics (MNPs) are emerging pollutants that can adsorb pollutants in the environment and biological molecules and ultimately affect human health. However, the aspects of adsorption of intracellular proteins onto MNPs and its biological effects in cells have not been investigated to date. The present study revealed that 100 nm polystyrene nanoplastics (NPs) could be internalized by THP-1 cells and specifically adsorbed intracellular proteins. In total, 773 proteins adsorbed onto NPs with high reliability were identified using the proteomics approach and analyzed via bioinformatics to predict the route and distribution of NPs following cellular internalization. The representative proteins identified via the Kyoto Encyclopedia of Genes and Genomes pathway analysis were further investigated to characterize protein adsorption onto NPs and its biological effects. The analysis revealed that NPs affect glycolysis through pyruvate kinase M (PKM) adsorption, trigger the unfolded protein response through the adsorption of ribophorin 1 (RPN1) and heat shock 70 protein 8 (HSPA8), and are chiefly internalized into cells through clathrin-mediated endocytosis with concomitant clathrin heavy chain (CLTC) adsorption. Therefore, this work provides new insights and research strategies for the study of the biological effects caused by NPs.

Meta-analysis of the hazards of microplastics in freshwaters using species sensitivity distributions

The environmental hazards of microplastics have raised concerns about their potential ecological risks. However, our understanding of the true risks may be limited because most laboratory studies used pristine microplastics. Here, we analyzed the available literature about ecotoxicological effects of microplastics, including weathered microplastics in particular, on freshwater biota and performed probabilistic species sensitivity distributions. The predicted no-effect concentrations for pristine microplastics were lower than those for weathered microplastics, both in mass concentration (6.1 and 4.8 × 102 μg/L) and number concentration (2.6 × 104 and 2.0 × 106 part/m3). In addition, the toxicological studies on microplastics contains often inconsistent and inconclusive information due to the complexity of the microplastics and the employed exposure conditions. The available data for Daphnia magna and Danio rerio was analyzed in detail to understand the effects of microplastic size, shape and polymer type on their ecotoxicity. Microplastic size was the biggest driving factor, followed by shape and polymer type. There was a tendency for increasing toxicity with smaller size, however, a high variability of effect data was observed for small microplastics. This study provided further insights into the effect thresholds for ecological risk assessment of microplastics and the effects of microplastic characteristics on toxicity.

Microplastics and Nanoplastics Impair the Biophysical Function of Pulmonary Surfactant by Forming Heteroaggregates at the Alveolar-Capillary Interface

Microplastics (MPs) are ubiquitous environmental pollutants produced through the degradation of plastic products. Nanoplastics (NPs), commonly coexisting with MPs in the environment, are submicrometer debris incidentally produced from fragmentation of MPs. We studied the biophysical impacts of MPs/NPs derived from commonly used commercial plastic products on a natural pulmonary surfactant extracted from calf lung lavage. It was found that in comparison to MPs/NPs derived from lunch boxes made of polypropylene or from drinking water bottles made of poly(ethylene terephthalate), the MP/NP derived from foam packaging boxes made of polystyrene showed the highest adverse impact on the biophysical function of the pulmonary surfactant. Accordingly, intranasal exposure of MP/NP derived from the foam boxes also induced the most serious proinflammatory responses and lung injury in mice. Atomic force microscopy revealed that NP particles were adsorbed on the air-water surface and heteroaggregated with the pulmonary surfactant film. These results indicate that although the incidentally formed NPs only make up a small mass fraction, they likely play a predominant role in determining the nano-bio interactions and the lung toxicity of MPs/NPs by forming heteroaggregates at the alveolar-capillary interface. These findings may provide novel insights into understanding the health impact of MPs and NPs on the respiratory system.

Airborne microplastics: A narrative review of potential effects on the human respiratory system

There has been growing evidence showing the widespread of airborne microplastics (AMPs) in many regions of the world, raising concerns about their impact on human health. This review aimed to consolidate recent literature on AMPs regarding their physical and chemical characteristics, deposition in the human respiratory tract, translocation, occurrence from human studies, and toxic effects determined in vitro and in vivo. The physical characteristics influence interactions with cell membranes, cellular internalization, accumulation, and cytotoxicity resulting from cell membrane damage and oxidative stress. In addition, prolonged exposure to AMP-associated toxic chemicals might lead to significant health effects. Most toxicological assessments of AMPs in vitro and in vivo have demonstrated that oxidative stress and inflammation are major mechanisms of action for their toxic effects. Elevated reactive oxygen species production could lead to mitochondrial dysfunction, inflammatory responses, and subsequent apoptosis in experimental models. To date, there has been some evidence suggesting exposure in humans. However, the data are still insufficient, and adverse human health effects need to be investigated. Future research on the existence, exposure, and health effects of AMPs is required for developing preventive and mitigation measures to protect human health.

Designing biodegradable alternatives to commodity polymers

The development and widespread adoption of commodity polymers changed societal landscapes on a global scale. Without the everyday materials used in packaging, textiles, construction and medicine, our lives would be unrecognisable. Through decades of use, however, the environmental impact of waste plastics has become grimly apparent, leading to sustained pressure from environmentalists, consumers and scientists to deliver replacement materials. The need to reduce the environmental impact of commodity polymers is beyond question, yet the reality of replacing these ubiquitous materials with sustainable alternatives is complex. In this tutorial review, we will explore the concepts of sustainable design and biodegradability, as applied to the design of synthetic polymers intended for use at scale. We will provide an overview of the potential biodegradation pathways available to polymers in different environments, and highlight the importance of considering these pathways when designing new materials. We will identify gaps in our collective understanding of the production, use and fate of biodegradable polymers: from identifying appropriate feedstock materials, to considering changes needed to production and recycling practices, and to improving our understanding of the environmental fate of the materials we produce. We will discuss the current standard methods for the determination of biodegradability, where lengthy experimental timescales often frustrate the development of new materials, and highlight the need to develop better tools and models to assess the degradation rate of polymers in different environments.