Compromised Autophagic Effect of Polystyrene Nanoplastics Mediated by Protein Corona Was Recovered after Lysosomal Degradation of Corona

Fate of polystyrene micro- and nanoplastics in zebrafish liver cells: Influence of protein corona on transport, oxidative stress, and glycolipid metabolism

Micro- and nanoplastics (MNPs) form protein corona (PC) upon contact with biological fluids, but their impact on the intracellular transport, distribution, and toxicity of MNPs remains unclear. Fetal bovine serum (FBS) and bovine serum albumin (BSA) were used to simulate in vivo environment, this study explored their influence on the transport and toxicity of polystyrene (PS) MNPs in zebrafish liver (ZFL) cells. Results showed PS MNPs were wrapped by proteins into stable complexes. Nanoparticles (NP, 50 nm) and their protein complexes (NP@PC) were internalized by cells within 6 h, with PC formation enhancing NP uptake. NP primarily entered cells through clathrin- and caveolae-mediated endocytosis, while NP@PC via clathrin-mediated pathways. Internalized particles were predominantly in lysosomes where PC degraded and some were also in mitochondria. Eventually, particles were expelled from cells through energy-dependent lysosomal pathways and energy-independent membrane penetration mechanisms. Notably, PC formation limited the clearance of NP. In toxicity, NP had a more severe impact than microplastics (MP, 5 μm). FBS more effectively mitigated PS MNPs-induced reactive oxygen species accumulation, subcellular structural damage, and dysregulation of glycolipid metabolism than BSA did. This study elucidates the modulatory role of PC on biological effects of MNPs, providing safety and risk management strategies.

Studies on adsorption and synergistic biological effects induced by microplastic particles and the Platanus pollen allergenic protein 3(Pla a3)

Microplastics (MPs) are pervasive as emerging pollutants in ambient particles and may pose a potential threat to human health through respiratory exposure. Especially, impact of climate change has led to an extended blooming period for many plants, resulting in elevated pollen levels in the air, and leading to a continuous increase in the number of individuals suffering from allergenic diseases. However, the interactions between the MPs and allergenic proteins, remain largely unexplored. In this study, we investigated cellular toxicity of the MPs and Platanus pollen allergenic protein (Pla a3) based on the characterization of two typical microplastics (polystyrene, PS and polyethylene, PE). Our results indicated that UV irradiation could make surface alterations of the MPs, including breakage, particle size reduction, and an increase in surface oxygen-containing functional groups. These changes significantly enhanced the adsorption of the Pla a 3 protein. The 'protein coronas' formed by the MPs and the Pla a3 caused more damage to the A549 cells than Pla a3 alone. Reactive oxygen species (ROS) generation and elevated superoxide dismutase (SOD) levels increased significantly after the A549 cells were exposure to the protein coronas. This excessive oxidative stress led to significant inflammation and cytokine production increase, with IL-1β, IL-4, IFN-γ, and TNF-α levels rising by 1.84 ± 0.01, 2.37 ± 0.04, 1.94 ± 0.09, and 2.19 ± 0.05-fold times respectively compared to that of the Pla a 3 exposure alone. This study provided a fundamental data for further research for the allergenicity induced by the pollen proteins.

Self-powered portable photoelectrochemical sensor based on dual-photoelectrode for microplastics detection

Plastic pollution has emerged as a significant global concern due to its potential threat to human health. The advancement of self-powered photoelectrochemical (PEC) sensors based on dual-photoelectrode presents ongoing challenges. The photoanode PEC analysis method is normally employed due to its remarkable photocurrent and low detection limit; however, it exhibits limited anti-interference capability in real sample detection. Conversely, the photocathode analysis method demonstrates excellent anti-interference detection capabilities, effectively mitigating the inherent disadvantages associated with the photoanode. Consequently, we have developed a self-powered PEC portable sensor that integrates both a photocathode and a photoanode, enabling accurate, sensitive, and convenient detection of polystyrene microplastics (PS MPs). Under optimal conditions, the sensor has a detection limit of 0.09 μg/mL, with a linear range from 0.5 to 1000 μg/mL. The method has good anti-interference ability to heavy metal ions and organics. In the presence of interfering substances, the accuracy can be maintained at over 97%. In addition, the sensor has demonstrated excellent performance in complex aquatic environments, providing an innovative design strategy for constructing PEC sensors aimed at detecting PS MPs.

Toxicity enhancement of microplastics released from food containers through thermal aging: Absorbing more serum proteins thus activating the innate immune response via actin polymerization

This study examined the effects of hot high-fat simulants on the physicochemical properties of microplastics (MPs) from polypropylene (PP)-, low-density polyethylene (LDPE)-, and polylactic acid (PLA)-based single-use food container (SUFC) leachates and those of aging on their immunomodulatory effectors. Scenario studies have demonstrated that MPs were released from these three types of SUFCs. LDPE- and PLA-based SUFCs also released cellulose. Among the SUFCs, only the PP leachates particles exhibited a new absorption peak at 1725 cm-1, which aging phenomenon may be attributed to the presence of unstable tertiary carbon atoms. Subsequently, we investigated the immunomodulatory effects of removing additive both PP and thermal-aged PP with polystyrene (PS) and carboxyl-modified PS (PS-COOH) polymer backbones as reference materials. The findings indicated that thermal-aged PP and PS-COOH induced comparable innate immune responses, with PS-COOH particles exhibiting a similar size to SUFC percolates. Consequently, PS and PS-COOH were selected as original and thermal-aged MPs, respectively, to evaluate the effects of aging on innate immunity. The results revealed thata protein corona formed on both particle types, with more protein adsorption observed on PS-COOH particles. The complex enhanced the phagocytosis of RAW264.7 macrophages and increased the expression of pro-inflammatory genes NOS2 and TNF-α through an actin polymerization cross-linking mechanism. In this study, we investigated how thermal-aged MPs affect innate immune responses using PS-COOH as a model system, emphasizing the importance of a comprehensive safety evaluations of MPs.

Exploring the Biological Effects of Polystyrene Nanoplastics on Spermatogenesis: Insights From Transcriptomic Analysis in Mouse Spermatocytes

The presence of polystyrene plastics in the human testis has raised concerns, yet their biological activity remains poorly characterized. This study aimed to investigate the biological effects and potential regulatory genes of polystyrene nanoplastics on spermatocyte line, GC-2spd(ts). After a 24-h exposure to polystyrene nanoplastics, the results indicated cell membrane disruption, impairment of mitochondrial membrane potential, increased levels of reactive oxygen species (ROS), and induced DNA damage. Furthermore, a comprehensive transcriptomic analysis was conducted, revealing differential gene expression patterns in GC-2spd(ts) cells in response to polystyrene nanoplastics. A total of 134 differentially expressed genes (DEGs) were identified, with 48 genes upregulated and 86 genes downregulated. The Gene Ontology analysis highlighted the involvement of these genes in various spermatogenesis-related biological processes, including acrosome reaction, sperm mitochondrial organization, sperm annulus, and outer acrosomal membrane. Subsequently, the quantification of gene expression through qRT-PCR identified five key genes (NSUN7, SEPTIN4, TRIM36, EQTN, and SYT8) screened from the DEGs. In conclusion, this study provides valuable insights into the biological effects of polystyrene nanoplastics on mouse spermatocytes using comprehensive transcriptomic analysis, contributing to the establishment of a foundation for future investigations into these relevant pathways.

Plastic particle impacts on the cardiovascular system and angiogenesis potential

The extensive application of plastics in different sectors such as packaging, building, textiles, consumer products, and several industries has increased in recent years. Emerging data have confirmed that plastic wastes and segregates are problematic issues in aquatic and terrestrial ecosystems. The decomposition of plastic particles (PPs) leads to the release of microplastics (MPs) and nanoplastics (NPs) into the surrounding environment and entry of these particles will be problematic in unicellular and multicellular creatures. It was suggested that PPs can easily cross all biological barriers and reach different organs, especially the cardiovascular system, with the potential to modulate several molecular pathways. It is postulated that the direct interaction of PPs with cellular and subcellular components induces genotoxicity and cytotoxicity within the cardiovascular system. Meanwhile, being inert carriers, PPs can intensify the toxicity of other contaminants inside the cardiovascular system. Here, in this review article, several underlying mechanisms related to PP toxicity in the cardiovascular system were discussed in detail.

Nano-sized polystyrene plastics toxicity: Necroptosis pathway caused by autophagy blockade and lysosomal dysfunction

The persistent detection of nano-sized plastic particles in humans, animals, and animal-derived products underscores the potential impact of these particles on living organisms. Consequently, the toxicology of such particles has emerged as a pivotal research interests in recent years. In this study, NP was synthesized successfully with an average particle size of 100 nm using a emulsion polymerization method as model particles. Following co-incubation of IEC-6 cells with NP for 24-168 h, a notable inhibition of cell viability and proliferation was observed. The significant activation of autophagy and a concomitant blockage of autophagic flux in IEC-6 cells after 24-72 h of co-incubation with NP were unveiled by transmission electron microscopy, western blotting, and double-fluorescent autophagy analysis. A significant increase in the number of lysosomes and an increase in the expression of hydrolase CTSB were detected, indicating dysregulation of lysosomal function. The subsequent transcriptomic and metabolomics analyses, coupled with the observation of activated lysosomes and the RIPK1-RIPK3-MLKL/PYGL pathway, led us to posit that the blockade of autophagy and lysosomal dysfunction, culminating in lysosomal membrane permeabilization (LMP) induced necroptosis, constitutes one of the mechanisms contributing to the cytotoxicity of NP. SYNOPSIS: The cytotoxicity and its related mechanisms of nano-plastic is still unclear. This study found that nano-plastics may induce necroptosis in cells, and autophagy blockade and lysosomal dysfunction are prodromal manifestations.

In vivo bioaccumulation and responses of hemocytes of mussels Perna viridis to microplastics and nanoplastics exposure

Growing micro- and nano-plastic (MNPs) pollution in the environment poses a threat to marine animals. Due to their excellent filtration capacity, bivalves can easily ingest MNPs, which could be translocated to open circulation system with potential risks. In the present study, the accumulation and elimination of MNPs (200 nm and 1 µm) in the mussel hemolymph serum and hemocytes were firstly quantified, and the differential sensitiveresponses of two subpopulations of hemocytes were then explored by in vivo exposure under environmentally relevant concentration of MNPs (200 µg/L). We demonstrated that MNPs were readily translocated into hemolymph serum, but were immediately followed by efficient internalization by hemocytes. Remarkably, concentrations of MNPs in hemolymph were only 0.63 and 0.39 times lower than the ambient exposure concentration. Granulocytes displayed a much higher potential of accumulating MNPs than the agranulocytes. MPs were more readily internalized by granulocytes, with their estimated maximum bioaccumulation factor (BCF) of 0.29 L/g. Due to the primary function of phagocytic encapsulation of MNPs by granulocytes, lysosome features especially the decline of subsequent lysosome membrane potential could be a potential sensitive biomarker in response to MNPs exposure. Our results provided insights on the bioaccumulation of MNPs at the cellular levels in marine bivalves.

Mechanisms of eco-corona effects on micro(nano)plastics in marine medaka: Insights into translocation, immunity, and energy metabolism

Biomolecules, prevalent in the marine environment, can readily adsorb onto the surface of micro(nano)plastics (MNPs), forming eco-corona. This study indicated that 50 nm polystyrene nanoplastics (NP50), whether wrapped with eco-corona or not, can passively enter embryos, whereas 5 µm polystyrene microplastics (MP5) cannot. Additionally, translocation of MP5 from the intestine to the liver was observed in larvae, a process facilitated by eco-corona. Notably, eco-corona prolonged the retention time of MNPs in larvae. However, NP50 was more challenging to purify than MP5, irrespective of the presence of eco-corona. Interestingly, eco-corona degraded in the intestine during the uptake of MNPs, and the hard coronae that readily formed on NP50 may restrict the degradation rate. Although NP50 significantly disrupted larval microbiota homeostasis compared with MP5, eco-corona was more likely to exacerbate MP5's damage to the intestine and liver by disrupting microbiota homeostasis. Additionally, NP50 caused more significant damage to immunity and energy metabolism compared with MP5, regardless of the presence of eco-corona. This study revealed that previously overlooked biomolecules in the marine environment can enhance the translocation of MNPs and subsequently exacerbate their toxic effects, providing theoretical support for assessing the ecological risks of MNPs in real environments.

Proteomics reveals that nanoplastics with different sizes induce hepatocyte apoptosis in mice through distinct mechanisms involving mitophagy dysregulation and cell cycle arrest

Nanoplastics (NPs) can penetrate the intestinal barrier of organisms and accumulate in the liver, thereby inducing hepatocyte apoptosis. However, the underlying mechanisms remain incompletely elucidated. This study examined the effects of PS-NPs exposure on hepatocyte apoptosis and revealed the role of cell cycle arrest and mitophagy. The C57BL/6 mice were administered a diet containing 100 nm and 500 nm PS-NPs at a concentration of 0.1 g/kg for 180 days, respectively. TUNEL staining confirmed that 100 nm PS-NPs induced more pronounced apoptosis compared to 500 nm PS-NPs in mouse liver. Mechanistically, proteomic analysis revealed that Pdcd2l, associated with the S phase of cell cycle and apoptosis, exhibited the highest fold changes among all detected proteins in 100 nm and 500 nm PS-NPs exposure groups. Notably, the expression of Tbc1d17, Bcl2l13, and Pgam5 involved in mitophagosome formation in mouse liver was upregulated by 100 nm PS-NPs but not by 500 nm PS-NPs; moreover, mitophagosomes were observed in HepG2 cells exposed to 100 nm PS-NPs. Additionally, 100 nm PS-NPs internalized by HepG2 cells could penetrate lysosomes. The protein levels of Igf2r and Rab7a were altered, and p62 mRNA expression was increased in mouse liver, suggesting 100 nm PS-NPs, but not 500 nm PS-NPs, impaired lysosomal function and subsequently inhibited mitophagy degradation. Collectively, 500 nm PS-NPs induced Pdcd2l-mediated cell cycle arrest, thereby exacerbating hepatocyte apoptosis; while 100 nm PS-NPs not only triggered similar levels of cell cycle arrest as 500 nm PS-NPs, but also disrupted mitophagy, which was also associated with hepatocyte apoptosis.

Polystyrene nanoplastics induce apoptosis, histopathological damage, and glutathione metabolism disorder in the intestine of juvenile East Asian river prawns (Macrobrachium nipponense)

Nanoplastics (NPs) are widely distributed in the aquatic environment and have become a global concern as a new type of pollutant. Many researchers have studied the physiological effects of NPs on aquatic organisms, but relatively little is known about their effects on intestinal immune function in crustaceans. Therefore, we used NPs concentrations of 0, 5, 10, 20, 40 mg/L for 28 days of stress, evaluated the effects of NPs exposure on intestinal cell apoptosis, histopathological damage, and glutathione (GSH) metabolism of juvenile East Asian river prawns (Macrobrachium nipponense). As NPs concentration increased, the contents of total GSH and oxidized glutathione decreased gradually (P < 0.05), the concentration of GSH first increased and then decreased (P < 0.05), and the activities of lysozyme, acid phosphatase, phenoloxidase, and alkaline phosphatase first increased and then decreased (P < 0.05). Additionally, intestinal tissue structure was damaged, and the apoptosis rate significantly increased (P < 0.05). The expression of intestinal autophagy genes (CTL, ALF, Crustin, ATG8, and BCL-2) increased at first and then decreased, the expression levels of TNF and Wnt4 significantly decreased, and the expression of Beclin significantly increased with increasing NPs concentration. We also found that AP-1 and PTEN were highly expressed in the hepatopancreas and were involved in intestinal immune responses. Our results showed that exposure to NPs may induce apoptosis of intestinal tissue cells, induce autophagy, and inhibit GSH metabolism, thereby reducing intestinal immune function of M. nipponense. These findings provide a reference for healthy aquaculture and ecological risk assessment of prawns.

A Comparative Study on the Interaction Between Protein and PET Micro/Nanoplastics: Structural and Surface Characteristics of Particles and Impacts on Lung Carcinoma Cells (A549) and Staphylococcus aureus

The interaction between particles and proteins is a key factor determining the toxicity responses of particles. Therefore, this study aimed to examine the interaction between the emerging pollutant polyethylene terephthalate micro/nanoplastics from water bottles with bovine serum albumin. The physicochemical characteristics of micro/nanoplastics were investigated using nuclear magnetic resonance, x-ray diffraction, Fourier transform infrared, dynamic light scattering, and x-ray energy dispersive spectroscopy after exposure to various concentrations and durations of protein. Furthermore, the impact of protein-treated micro/nanoplastics on biological activities was examined using the mitochondrial activity and membrane integrity of A549 cells and the activity and biofilm production of Staphylococcus aureus. The structural characteristics of micro/nanoplastics revealed an interaction with protein. For instance, the assignment of protein-related new proton signals (e.g., CH2, methylene protons of CH2O), changes in available protons s (e.g., CH and CH3), crystallinity, functional groups, elemental ratios, zeta potentials (-11.3 ± 1.3 to -12.4 ± 1.7 to 25.5 ± 2.3 mV), and particle size (395 ± 76 to 496 ± 60 to 866 ± 82 nm) of micro/nanoplastics were significantly observed after protein treatment. In addition, the loading (0.012-0.027 mM) and releasing (0.008-0.013 mM) of protein also showed similar responses with structural characteristics. Moreover, the cell-based responses were changed regarding the structural and surface characteristics of micro/nanoplastics and the loading efficiencies of protein. For example, insignificant mitochondrial activity (2%-10%) and significant membrane integrity (12%-28%) of A549 cells increased compared with control, and reductions in bacterial activity (5%-40%) in many cases and biofilm production specifically at low dose of all treatment stages (13%-46% reduction) were observed.

Peptide-coated DNA nanostructures as a platform for control of lysosomal function in cells

DNA nanotechnology is a rapidly growing field that provides exciting tools for biomedical applications. Targeting lysosomal functions with nanomaterials, such as DNA nanostructures (DNs), represents a rational and systematic way to control cell functionality. Here we present a versatile DNA nanostructure-based platform that can modulate a number of cellular functions depending on the concentration and surface decoration of the nanostructure. Utilizing different peptides for surface functionalization of DNs, we were able to rationally modulate lysosomal activity, which in turn translated into the control of cellular function, ranging from changes in cell morphology to modulation of immune signaling and cell death. Low concentrations of decalysine peptide-coated DNs induced lysosomal acidification, altering the metabolic activity of susceptible cells. In contrast, DNs coated with an aurein-bearing peptide promoted lysosomal alkalization, triggering STING activation. High concentrations of decalysine peptide-coated DNs caused lysosomal swelling, loss of cell-cell contacts, and morphological changes without inducing cell death. Conversely, high concentrations of aurein-coated DNs led to lysosomal rupture and mitochondrial damage, resulting in significant cytotoxicity. Our study holds promise for the rational design of a new generation of versatile DNA-based nanoplatforms that can be used in various biomedical applications, like the development of combinatorial anti-cancer platforms, efficient systems for endolysosomal escape, and nanoplatforms modulating lysosomal pH.

Comprehensive insights into mechanism of nanotoxicity, assessment methods and regulatory challenges of nanomedicines

Nanomedicine has the potential to transform healthcare by offering targeted therapies, precise diagnostics, and enhanced drug delivery systems. The National Institutes of Health has coined the term "nanomedicine" to describe the use of nanotechnology in biological system monitoring, control, diagnosis, and treatment. Nanomedicine continues to receive increasing interest for the rationalized delivery of therapeutics and pharmaceutical agents to achieve the required response while reducing its side effects. However, as nanotechnology continues to advance, concerns about its potential toxicological effects have also grown. This review explores the current state of nanomedicine, focusing on the types of nanoparticles used and their associated properties that contribute to nanotoxicity. It examines the mechanisms through which nanoparticles exert toxicity, encompassing various cellular and molecular interactions. Furthermore, it discusses the assessment methods employed to evaluate nanotoxicity, encompassing in-vitro and in-vivo models, as well as emerging techniques. The review also addresses the regulatory issues surrounding nanotoxicology, highlighting the challenges in developing standardized guidelines and ensuring the secure translation of nanomedicine into clinical settings. It also explores into the challenges and ethical issues associated with nanotoxicology, as understanding the safety profile of nanoparticles is essential for their effective translation into therapeutic applications.

Protein Corona Formation on Cadmium-Bearing Nanoparticles: Important Role of Facet-Dependent Binding of Cysteine-Rich Proteins

Cadmium-bearing nanoparticles, such as nanoparticulate cadmium selenide (CdSe) and cadmium sulfide (CdS), widely exist in the environment and originate from both natural and anthropogenic sources. Risk assessment of these nanoparticles cannot be accurate without taking into account the properties of the protein corona that is acquired by the nanoparticles upon biouptake. Here, we show that the compositions of the protein corona on CdSe/CdS nanoparticles are regulated collectively by the surface atomic arrangement of the nanoparticles and the abundance and distribution of cysteine moieties of the proteins in contact with the nanoparticles. A proteomic analysis shows that the observed facet-dependent preferential binding of proteins is mostly related to the cysteine contents of the proteins, among commonly recognized protein properties controlling the formation of the protein corona. Theoretical calculations further demonstrate that the atomic arrangement of surface Cd atoms, as dictated by the exposed facets of the nanoparticles, controls the specific binding mode of the S atoms in the disulfide bonds of the proteins. Supplemental protein adsorption experiments confirm that disulfide bonds remain intact during protein adsorption, making the binding of protein molecules sensitive to the abundance and distribution of Cd-binding moieties and possibly molecular rigidity of the proteins. The significant conformational changes of adsorbed proteins evidenced from a circular dichroism spectroscopy analysis suggest that disrupting the structural stability of proteins may be an additional risk factor of Cd-bearing nanoparticles. These findings underline that the unique properties and behaviors of nanoparticles must be fully considered when evaluating the biological effects and health risks of metal pollutants.

Protein corona alleviates adverse biological effects of nanoplastics in breast cancer cells

Pollution from micro- and nanoplastics (MNPs) has long been a topic of concern due to its potential impact on human health. MNPs can circulate through human blood and, thus far, have been found in the lungs, spleen, stomach, liver, kidneys and even in the brain, placenta, and breast milk. While data are already available on the adverse biological effects of pristine MNPs (e.g. oxidative stress, inflammation, cytotoxicity, and even cancer induction), no report thus far clarified whether the same effects are modulated by the formation of a protein corona around MNPs. To this end, here we use pristine and human-plasma pre-coated polystyrene (PS) nanoparticles (NPs) and investigate them in cultured breast cancer cells both in terms of internalization and cell biochemical response to the exposure. It is found that pristine NPs tend to stick to the cell membrane and inhibit HER-2-driven signaling pathways, including phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways, which are associated with cancer cell survival and growth. By contrast, the formation of a protein corona around the same NPs can promote their uptake by endocytic vesicles and final sequestration within lysosomes. Of note is that such intracellular fate of PS-NPs is associated with mitigation of the biochemical alterations of the phosphorylated AKT (pAKT)/AKT and phosphorylated ERK (pERK)/ERK levels. These findings provide the distribution of NPs in human breast cancer cells, may broaden our understanding of the interactions between NPs and breast cancer cells and underscore the crucial role of the protein corona in modulating the impact of MNPs on human health.

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.

Alleviating binary toxicity of polystyrene nanoplastics and atrazine to Chlorella vulgaris through humic acid interaction: Long-term toxicity using environmentally relevant concentrations

In this study, microalgae Chlorella vulgaris (C. vulgaris) were simultaneously exposed to environmental concentrations of amino-functionalized polystyrene nanoplastics (PS-NH2; 0.05, 0.1, 0.2, 0.3 and 0.4 mg/L) and the world's second most used pesticide, the herbicide atrazine (ATZ; 10 μg/L), in the absence and presence of humic acid (HA; 1 mg/L) for 21 days. Due to the low concentrations of PS-NH2, the majority of them could not cause a significant difference in the end-points of biomass, chlorophylls a and b, total antioxidant, total protein, and superoxide dismutase and malondialdehyde compared to the control group (p > 0.05). On the other hand, by adding ATZ to the PS-NH2, all the mentioned end-point values showed a considerable difference from the control (p < 0.05). The exposure of PS-NH2+ATZ treatments to the HA could remarkably reduce their toxicity, additionally, HA was able to decrease the changes in the expression of genes related to oxidative stress (e.g., superoxide dismutase, glutathione reductase, and catalase) in the C. vulgaris in the most toxic treatment group (e.g., PS-NH2+ATZ). The synergistic toxicity of the PS-NH2+ATZ group could be due to their enhanced bioavailability for algal cells. Nevertheless, the toxicity alleviation in the PS-NH2+ATZ treatment group after the addition of HA could be due to the eco-corona formation, and changes in their zeta potential from positive to negative value, which would increase their electrostatic repulsion with the C. vulgaris cells, in such a way that HA also caused a decrease in the formation of C. vulgaris-NPs hetero-aggregates. This research underscores the complex interplay between PS-NH2, ATZ, and HA in aquatic environments and their collective impact on microalgal communities.

Tracking the Cellular Degradation of Silver Nanoparticles: Development of a Generic Kinetic Model

Understanding the degradation of nanoparticles (NPs) after crossing the cell plasma membrane is crucial in drug delivery designs and cytotoxicity assessment. However, the key factors controlling the degradable kinetics remain unclear due to the absence of a quantification model. In this study, subcellular imaging of silver nanoparticles (AgNPs) was used to determine the intracellular transfer of AgNPs, and single particle ICP-MS was utilized to track the degradation process. A cellular kinetic model was subsequently developed to describe the uptake, transfer, and degradation behaviors of AgNPs. Our model demonstrated that the intracellular degradation efficiency of AgNPs was much higher than that determined by mimicking testing, and the degradation of NPs was highly influenced by cellular factors. Specifically, deficiencies in Ca or Zn primarily decreased the kinetic dissolution of NPs, while a Ca deficiency also resulted in the retardation of NP transfer. The biological significance of these kinetic parameters was strongly revealed. Our model indicated that the majority of internalized AgNPs dissolved, with the resulting ions being rapidly depurated. The release of Ag ions was largely dependent on the microvesicle-mediated route. By changing the coating and size of AgNPs, the model results suggested that size influenced the transfer of NPs into the degradation process, whereas coating affected the degradation kinetics. Overall, our developed model provides a valuable tool for understanding and predicting the impacts of the physicochemical properties of NPs and the ambient environment on nanotoxicity and therapeutic efficacy.

Plastic particles affect N2O release via altering core microbial metabolisms in constructed wetlands

Constructed wetlands (CWs) have been proven to effectively immobilize plastic particles. However, little is known about the differences in the impact of varying sized plastic particles on nitrous oxide (N2O) release, as well as the intervention mechanisms in CWs. Here, we built a lab-scale wetland model and introduced plastic particles of macro-, micro-, and nano-size at 100 μg/L for 370 days. The results showed that plastic particles of all sizes reduced N2O release in CWs, with the degrees being the strongest for the Nano group, followed by Micro and Macro groups. Meanwhile, 15N- and 18O-tracing experiment revealed that the ammoxidation process contributed the most N2O production, followed by denitrification. While for every N2O-releasing process, the contributing proportion of N2O in nitrification-coupled denitrification were most significantly cut down under exposing to macro-sized plastics and had an obvious increase in nitrifier denitrification in all groups, respectively. Finally, we revealed the three mechanism pathways of N2O release reduction with macro-, micro-, and nano-sized plastics by impacting carbon assimilation (RubisCO activity), ammonia oxidation (gene amo abundance and HAO activity), and N-ion transmembrane and reductase activities, respectively. Our findings thus provided novel insights into the potential effects of plastic particles in CWs as an eco-technology.

Mass quantification of nanoplastics at wastewater treatment plants by pyrolysis-gas chromatography-mass spectrometry

Municipal wastewater treatment plants (WWTPs) play a crucial role in the collection and redistribution of plastic particles from both households and industries, contributing to their presence in the environment. Previous studies investigating the levels of plastics in WWTPs, and their removal rates have primarily focused on polymer type, size, shape, colour, and particle count, while comprehensive understanding of the mass concentration of plastic particles, particularly those <1 µm (nanoplastics), remains unclear and lacking. In this study, pyrolysis gas chromatography-mass spectrometry was used to simultaneously determine the mass concentration of nine selected polymers (i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), nylon 6, nylon 66, polyvinylchloride (PVC), poly(methyl methacrylate) (PMMA) and polycarbonate (PC)) below 1 µm in size across the treatment processes or stages of three WWTPs in Australia. All the targeted nanoplastics were detected at concentrations between 0.04 and 7.3 µg/L. Nylon 66 (0.2-7.3 µg/L), PE (0.1-6.6 µg/L), PP (0.1-4.5 µg/L), Nylon 6 (0.1-3.6 µg/L) and PET (0.1-2.2 µg/L), were the predominant polymers in the samples. The mass concentration of the total nanoplastics decreased from 27.7, 18 and 9.1 µg/L in the influent to 1, 1.4 and 0.8 µg/L in the effluent, with approximate removal rates of 96 %, 92 % and 91 % in plants A, B and C, respectively. Based on annual wastewater effluent discharge, it is estimated that approximately 24, 2 and 0.7 kg of nanoplastics are released into the environment per year for WWTPs A, B and C, respectively. This study investigated the mass concentrations and removal rates of nanoplastics with a size range of 0.01-1 µm in wastewater, providing important insight into the pollution levels and distribution patterns of nanoplastics in Australian WWTPs.

The impact of nanomaterials on autophagy across health and disease conditions

Autophagy, a catabolic process integral to cellular homeostasis, is constitutively active under physiological and stress conditions. The role of autophagy as a cellular defense response becomes particularly evident upon exposure to nanomaterials (NMs), especially environmental nanoparticles (NPs) and nanoplastics (nPs). This has positioned autophagy modulation at the forefront of nanotechnology-based therapeutic interventions. While NMs can exploit autophagy to enhance therapeutic outcomes, they can also trigger it as a pro-survival response against NP-induced toxicity. Conversely, a heightened autophagy response may also lead to regulated cell death (RCD), in particular autophagic cell death, upon NP exposure. Thus, the relationship between NMs and autophagy exhibits a dual nature with therapeutic and environmental interventions. Recognizing and decoding these intricate patterns are essential for pioneering next-generation autophagy-regulating NMs. This review delves into the present-day therapeutic potential of autophagy-modulating NMs, shedding light on their status in clinical trials, intervention of autophagy in the therapeutic applications of NMs, discusses the potency of autophagy for application as early indicator of NM toxicity.

Micro(nano)-plastics exposure induced programmed cell death and corresponding influence factors

Plastic products have played an indispensable role in our daily lives for several decades, primarily due to their cost-effectiveness and unmatched convenience. Nevertheless, recent developments in nanotechnology have propelled our attention toward a distinct category of plastic fine particulates known as micro(nano)-plastics (MPs/NPs). The investigation of the cytotoxic effects of MPs/NPs has emerged as a central and burgeoning area of research in environmental toxicology and cell biology. In the scope of this comprehensive review, we have meticulously synthesized recent scientific inquiries to delve into the intricate interplay between MPs/NPs and programmed cell death mechanisms, which encompass a range of highly regulated processes. First, the signaling pathways and molecular mechanisms of different programmed death modalities induced by MPs/NPs were elaborated, including apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. The causes of different programmed deaths induced by MPs/NPs, such as size, surface potential, functional group modification, aging, biological crown, and co-exposure of MPs/NPs are further analyzed. In contrast, the various cellular programmed death modes induced by MPs/NPs are not alone most of the time, and lastly, the connections between different cellular programmed death modes induced by MPs/NPs, such as interconversion, mutual promotion, and mutual inhibition, are explained. Our primary objective is to unveil the multifaceted toxicological implications of MPs/NPs on the intricate web of cellular fate and biological homeostasis. This endeavor not only broadens our understanding of the potential risks associated with MPs/NPs exposure but also underscores the urgent need for comprehensive risk assessments and regulatory measures in the context of environmental health.

Aging of polypropylene plastic and impacts on microbial community structure in constructed wetlands

The COVID-19 pandemic has resulted in a substantial surge in the usage of disposable plastic masks, generating a significant volume of waste and contributing to environmental pollution. Wetland ecosystems function as crucial repositories for terrestrial pollutants and are highly effective in retaining disposable masks composed mainly of PP material. These masks can endure extended periods in wetlands, experiencing natural degradation that may have potential implications on wetland ecosystems. Our findings demonstrate the natural aging process of disposable masks, resulting in the generation of microplastics (MPs) ranging in diameter from 10 to 30 μm over a 180-day timeframe. Examination of 16S rDNA data unveiled temporal fluctuations in microbial diversity in the wetland ecosystem. Initially, microbial diversity displayed a modest incline, which was succeeded by a subsequent decrease. With the progressive accumulation of plastic within the wetland, an ongoing decline in microbial diversity linked to nitrogen transformation was observed. This study provides valuable insights into the retention of disposable masks by wetlands amidst the COVID-19 pandemic, along with their consequential effects on wetland ecosystems, specifically pertaining to nitrogen cycling. It underscores the urgency of augmenting the safeguarding measures for wetland ecosystems.

Nanoplastic propels diet-induced NAFL to NASH via ER-mitochondrial tether-controlled redox switch

Nonalcoholic steatohepatitis (NASH) is multifactorial that lifestyle, genetic, and environmental factors contribute to its onset and progression, thereby posing a challenge for therapeutic intervention. Nanoplastic (NP) is emerged as a novel environmental metabolism disruptor but the etiopathogenesis remains largely unknown. In this study, C57BL/6 J mice were fed with normal chow diet (NCD) and high-fat diet (HFD) containing 70 nm polystyrene microspheres (NP). We found that dietary-derived NP adsorbed proteins and agglomerated during the in vivo transportation, enabling diet-induced hepatic steatosis to NASH. Mechanistically, NP promoted liver steatosis by upregulating Fatp2. Furthermore, NP stabilized the Ip3r1, and facilitated ER-mitochondria contacts (MAMs) assembly in the hepatocytes, resulting in mitochondrial Ca2+ overload and redox imbalance. The redox-sensitive Nrf2 was decreased in the liver of NP-exposed mice, which positively regulated miR26a via direct binding to its promoter region [-970 bp to -847 bp and -318 bp to -176 bp]. NP decreased miR26a simultaneously upregulated 10 genes involved in MAMs formation, lipid uptake, inflammation, and fibrosis. Moreover, miR26a inhibition elevated MAMs-tether Vdac1, which promoted the nucleus translocation of NF-κB P65 and Keap1 and functionally inactivated Nrf2, leading to a vicious cycle. Hepatocyte-specific overexpressing miR26a effectively restored ER-mitochondria miscommunication and ameliorated NASH phenotype in NP-exposed and Keap1-overexpressed mice on HFD. The hepatic MAM-tethers/Nrf2/miR26a feedback loop is an essential metabolic switch from simple steatosis to NASH and a promising therapeutic target for oxidative stress-associated liver damage and NASH.

Coronal ApoE Protein Combines with LRP1 to Inactivate GSK3β That Mitigates Silica Nanoparticle-Induced Brain Lesion

Silica nanoparticles (SiO2 NPs) are widely used engineered materials that warrant their obvious environmental exposure risk. Our previous study has shown that different routes of SiO2 NP exposure on the glycogen synthase kinase 3 beta (GSK3β) activity were related to the serum proteins enriched on the surface of SiO2 NPs, which implied that a particular protein in the serum changed the inherent toxic behavior of SiO2 NPs and inhibited the activation of GSK3β by SiO2 NPs. Here, we identified that the SiO2 NP surface enriched a large amount of apolipoprotein E (ApoE), and the ApoE protein corona bound to the lipoprotein receptor-related protein 1 (LRP1) to inactivate GSK3β, thereby reducing the damage of SiO2 NPs to the brain. This work presented the first evidence that specific biocorona reduced the toxicity of SiO2 NPs at the molecular level, which helped to elucidate the role of specific corona components on nanotoxicity.

Quantitative analysis of nanoplastics in environmental and potable waters by pyrolysis-gas chromatography-mass spectrometry

Nanoplastics are emerging environmental contaminants, but their presence in environmental and potable water remains largely understudied due to the absence of quantitative analytical methods. In this study, we developed and validated a pretreatment method that combines hydrogen peroxide digestion and Amicon® Stirred Cell ultrafiltration (at 100 kDa, approximately 10 nm) with subsequent detection by pyrolysis gas chromatography-mass spectrometry (Pyr-GC/MS). This method allows for the simultaneous identification and quantification of nine selected nanoplastic types, including poly(ethylene terephthalate) (PET), polyethylene (PE), polycarbonate (PC), polypropylene (PP), poly(methyl methacrylate) (PMMA), polystyrene (PS), polyvinylchloride (PVC), nylon 6, and nylon 66, in environmental and potable water samples based on polymer-specific mass concentration. Limits of quantification ranged from 0.01 to 0.44 µg/L, demonstrating the method's ability to quantitatively detect nanoplastics in environmental and potable water samples. Most of the selected nanoplastics were detected at concentrations of between 0.04 and 1.17 µg/L, except for PC, which was consistently below the limit of detection (<0.44 µg/L). The prevalent polymer components in the samples were PE (0.10 - 1.17 µg/L), PET (0.06 - 0.91 µg/L), PP (0.04 - 0.79 µg/L), and PS (0.06 - 0.53 µg/L) nanoplastics. The presented analytical method offers an accurate means to identify, quantify, and monitor nanoplastics in complex environmental and potable water samples. It fills gaps in our understanding of nanoplastic pollution levels, providing a valuable methodology and crucial reference data for future studies.

Recent progress and future directions of the research on nanoplastic-induced neurotoxicity

Many types of plastic products, including polystyrene, have long been used in commercial and industrial applications. Microplastics and nanoplastics, plastic particles derived from these plastic products, are emerging as environmental pollutants that can pose health risks to a wide variety of living organisms, including humans. However, it is not well understood how microplastics and nanoplastics affect cellular functions and induce stress responses. Humans can be exposed to polystyrene-microplastics and polystyrene-nanoplastics through ingestion, inhalation, or skin contact. Most ingested plastics are excreted from the body, but inhaled plastics may accumulate in the lungs and can even reach the brain via the nose-to-brain route. Small-sized polystyrene-nanoplastics can enter cells by endocytosis, accumulate in the cytoplasm, and cause various cellular stresses, such as inflammation with increased pro-inflammatory cytokine production, oxidative stress with generation of reactive oxygen species, and mitochondrial dysfunction. They induce autophagy activation and autophagosome formation, but autophagic flux may be impaired due to lysosomal dysfunction. Unless permanently exposed to polystyrene-nanoplastics, they can be removed from cells by exocytosis and subsequently restore cellular function. However, neurons are very susceptible to this type of stress, thus even acute exposure can lead to neurodegeneration without recovery. This review focuses specifically on recent advances in research on polystyrene-nanoplastic-induced cytotoxicity and neurotoxicity. Furthermore, in this review, based on mechanistic studies of polystyrene-nanoplastics at the cellular level other than neurons, future directions for overcoming the negative effects of polystyrene-nanoplastics on neurons were suggested.

Polystyrene nanoparticles induced mammalian intestine damage caused by blockage of BNIP3/NIX-mediated mitophagy and gut microbiota alteration

Nanoplastics possess the capacity for cellular internalization, and consequentially disrupt mitochondrial functionality, precipitating aberrations in energy metabolism. Given this, the potential accumulation of nanoplastics in alimentary sources presents a considerable hazard to the mammalian gastrointestinal system. While mitophagy serves as a cytoprotective mechanism that sustains redox homeostasis through the targeted removal of compromised mitochondria, the regulatory implications of mitophagy in nanoplastic-induced toxicity remain an underexplored domain. In the present investigation, polystyrene (PS) nanoparticles, with a diameter of 80 nm employed as a representative model to assess their toxicological impact and propensity to instigate mitophagy in intestinal cells both in vitro and in vivo. Data indicated that PS nanoparticles elicited BNIP3/NIX-mediated mitophagy within the intestinal milieu. Strikingly, the impediment of this degradation process at elevated concentrations was correlated with exacerbated pathological ramifications. In vitro assays corroborated that high-dosage cellular uptake of PS nanoparticles obstructed the mitophagy pathway. Furthermore, treatment with PS nanoparticles engendered alterations in gut microbiota composition and manifested a proclivity to modulate nutritional metabolism. Collectively, these findings elucidate that oral exposure to PS nanoparticles culminates in the inhibition of mitophagy and induces perturbations in the intestinal microbiota. This contributes valuable insights into the toxicological repercussions of nanoplastics on mammalian gastrointestinal health.

Compound effect and mechanism of oxidative damage induced by nanoplastics and benzo [a] pyrene

Nanoplastics and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soil environments. In order to objectively evaluate the toxic interaction between polystyrene nanoplastics (PS NPs) and benzo [a] pyrene (BaP), oxidative damage at the level of earthworm cells and biomacromolecules was investigated by experiments combined with molecular dynamics simulation. Studies on cells reveal that PS NPs and BaP had synergistic toxicity when it came to causing oxidative stress. Cellular reactive oxygen species (ROS) levels under combined pollutant exposure were 24% and 19% higher, respectively than when PS NPs and BaP were exposed alone (compared to the blank group). In addition, BaP and PS NPs inhibited the ability of CAT to decompose H2O2 by affecting the structure of the proximal amino acid Tyr 357 in the active center of CAT, which exacerbated oxidative stress to a certain extent. Therefore, the synergistic toxic effect of BaP and PS NPs is due to the mutual complement of the two to the induction of protein structural looseness, and the strengthening of the stability of the conjugate (CAT-BaP-PS) under the weak interaction. This work provides a new perspective and approach on how to talk about the toxicity of combined pollutants.

The interplay between lysosome, protein corona and biological effects of cationic carbon dots: Role of surface charge titratability

Carbon dots (CDs) are nanoparticles (NPs) with potential applications in the biomedical field. When in contact with biological fluids, most NPs are covered by a protein corona. As well, upon cell entry, most NP are sequestered in the lysosome. However, the interplay between the lysosome, the protein corona and the biological effects of NPs is still poorly understood. In this context, we investigated the role of the lysosome in the toxicological responses evoked by four cationic CDs exhibiting protonatable or non-protonatable amine groups at their surface, and the associated changes in the CD protein corona. The four CDs accumulated in the lysosome and led to lysosomal swelling, loss lysosome integrity, cathepsin B activation, NLRP3 inflammasome activation, and cell death by pyroptosis in a human macrophage model, but with a stronger effect for CDs with titratable amino groups. The protein corona formed around CDs in contact with serum partially dissociated under lysosomal conditions with subsequent protein rearrangement, as assessed by quantitative proteomic analysis. The residual protein corona still contained binding proteins, catalytic proteins, and proteins involved in the proteasome, glycolysis, or PI3k-Akt KEGG pathways, but with again a more pronounced effect for CDs with titratable amino groups. These results demonstrate an interplay between lysosome, protein corona and biological effects of cationic NPs in link with the titratability of NP surface charges.

Visible-light-induced self-propelled nanobots against nanoplastics

The accumulation of plastic debris in aquatic organisms has raised serious concerns about the potential health implications of their incorporation into the food chain. However, conventional water remediation techniques are incapable of effectively removing nanoplastics (NPs) smaller than 200 nm, which can have harmful effect on animal and human health. Herein, we demonstrate the "on-the-fly" capture of NPs through their enlargement (approximately 4,100 times) using self-propelled nanobots composed of a metal-organic framework. Under visible-light irradiation, the iron hexacyanoferrate (FeHCF) nanobot exhibits fuel-free motion by electrostatically adsorbing NPs. This strategy can contribute to reducing plastic pollution in the environment, which is a significant environmental challenge. Light-induced intervalence charge transfer in the FeHCF nanobot lattice induces bipolarity on the nanobot surface, leading to the binding of negatively charged NPs. The local electron density in the lattice then triggers self-propulsion, thereby inducing agglomeration of FeHCF@NP complexes to stabilize their metastable state. The FeHCF nanobot exhibits a maximum removal capacity of 3,060 mg∙g-1 and rate constant of 0.69 min-1, which are higher than those recorded for materials reported in the literature.

Micro- and nanoplastics (MNPs) and their potential toxicological outcomes: State of science, knowledge gaps and research needs

Plastic waste has been produced at a rapidly growing rate over the past several decades. The environmental impacts of plastic waste on marine and terrestrial ecosystems have been recognized for years. Recently, researchers found that micro- and nanoplastics (MNPs), micron (100 nm - 5 mm) and nanometer (1 - 100 nm) scale particles and fibers produced by degradation and fragmentation of plastic waste in the environment, have become an important emerging environmental and food chain contaminant with uncertain consequences for human health. This review provides a comprehensive summary of recent findings from studies of potential toxicity and adverse health impacts of MNPs in terrestrial mammals, including studies in both in vitro cellular and in vivo mammalian models. Also reviewed here are recently released biomonitoring studies that have characterized the bioaccumulation, biodistribution, and excretion of MNPs in humans. The majority MNPs in the environment to which humans are most likely to be exposed, are of irregular shapes, varied sizes, and mixed compositions, and are defined as secondary MNPs. However, the MNPs used in most toxicity studies to date were commercially available primary MNPs of polystyrene (PS), polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and other polymers. The emerging in vitro and in vivo evidence reviewed here suggests that MNP toxicity and bioactivity are largely determined by MNP particle physico-chemical characteristics, including size, shape, polymer type, and surface properties. For human exposure, MNPs have been identified in human blood, urine, feces, and placenta, which pose potential health risks. The evidence to date suggests that the mechanisms underlying MNP toxicity at the cellular level are primarily driven by oxidative stress. Nonetheless, large knowledge gaps in our understanding of MNP toxicity and the potential health impacts of MNP exposures still exist and much further study is needed to bridge those gaps. This includes human population exposure studies to determine the environmentally relevant MNP polymers and exposure concentrations and durations for toxicity studies, as well as toxicity studies employing environmentally relevant MNPs, with surface chemistries and other physico-chemical properties consistent with MNP particles in the environment. It is especially important to obtain comprehensive toxicological data for these MNPs to understand the range and extent of potential adverse impacts of microplastic pollutants on humans and other organisms.

Impact of food matrices on the characteristics and cellular toxicities of ingested nanoplastics in a simulated digestive tract

Microplastic and nanoplastic (MNP) pollution has become a major global food safety concern. MNPs can interact with food matrices, and their passage through the gastrointestinal tract can modify their properties. To explore whether and how food matrices influence MNP toxicity, we investigated the interactions between polystyrene nanoplastics (PS-NPs) and food matrices, using an in vitro gastrointestinal digestion model. Then, we tested cell viability, particle uptake and cellular toxicities induced by PS-NPs with food matrices in Caco-2 cells. The results showed that PS-NPs were aggregated, both with and without food matrices, after in vitro gastrointestinal digestion. Glyceryl trioleate exerted greater ability to stabilize digestas and to disperse PS-NPs than starch and bovine serum albumin. The protein corona's protein composition on PS-NPs varied when it interacted with different food matrices. Moreover, when combined with food matrices, the PS-NPs' uptake was enhanced, thus aggravating cellular inflammation, stress, and apoptosis levels. Finally, through co-exposure to a mixture of food matrices, we found a combined negative effect of PS-NPs and cadmium on cellular inflammation, stress, and apoptosis levels. This is the first study to compare the impact of various food matrices on the characteristics and cellular toxicities of ingested NPs in a simulated digestive tract.

Ecotoxicological significance of bio-corona formation on micro/nanoplastics in aquatic organisms

The unsustainable manufacturing, utilization and inadequate handling of plastics have led to a surge in global plastic pollution. In recent times, there has been increasing concern about the plausible hazards associated with exposure to micro/nanoplastics (M/NPs). As aquatic systems are considered to be the likely sink for M/NPs, it is crucial to comprehend their environmental behavior. The bioavailability, toxicity and fate of M/NPs in the environment are predominantly dictated by their surface characteristics. In the aquatic environment, M/NPs are prone to be internalized by aquatic organisms. This may facilitate their interaction with a diverse array of biomolecules within the organism, resulting in the formation of a biocorona (BC). The development of BC causes modifications in the physicochemical attributes of the M/NPs including changes to their size, stability, surface charge and other properties. This review details the concept of BC formation and its underlying mechanism. It provides insight on the analytical techniques employed for characterizing BC formation and addresses the associated challenges. Further, the eco-toxicological implications of M/NPs and the role of BC in modifying their potential toxicity on aquatic organisms is specified. The impact of BC formation on the fate and transport of M/NPs is discussed. A concise outlook on the future perspectives is also presented.

Polystyrene microplastics promote liver inflammation by inducing the formation of macrophages extracellular traps

Microplastics (MPs), a new and increasing environmental pollutant, can cause ongoing damage to organisms. Although recent studies have revealed mechanisms of action for some of the hepatotoxicity caused by MPs, the role-played by cellular interactions, particularly immune cells, in the process of liver injury has not been elucidated. In the present study, 5-μm polystyrene microplastics (PS-MPs) induced liver inflammation as well as the formation of Macrophage extracellular traps (METs). Macrophage and LMH cell co-culture systems confirmed that PS-MPs-induced METs promote inflammation in hepatocytes. Mechanistically, macrophages actively phagocytose particles after 4 h of exposure to PS-MPs. Subsequently PS-MPs elevated ROS levels and disrupt mitochondrial kinetic homeostasis. Further activation of mitochondrial autophagy and lysosomes. After phagocytosis of PS-MPs by macrophages for 12 h, continued autophagy and lysosome activation eventually lead to lysosome rupture and release of calcium ions to induce the formation of METs. Blocking ROS (NAC) and autophagy (3MA) partially alleviated mitochondrial and lysosomal damage and thus inhibited the formation of METs induced by PS-MPs. NAC also delayed the onset of respiratory burst to alleviate METs formation. In conclusion, our study reveals the mechanism of METs formation in liver inflammation induced by PS-MPs exposure and suggests that lysosomal damage may be one of the key players in the formation of METs induced by PS-MPs.

Differently surface-labeled polystyrene nanoplastics at an environmentally relevant concentration induced Crohn's ileitis-like features via triggering intestinal epithelial cell necroptosis

Nanoplastics (NPs), regarded as the emerging contaminants, can enter and be mostly accumulated in the digest tract, which pose the potential threat to intestinal health. In this study, mice were orally exposed to polystyrene (PS), PS-COOH and PS-NH₂ NPs with the size of ∼100 nm at a human equivalent dose for 28 consecutive days. All three kinds of PS-NPs triggered Crohn's ileitis-like features, such as ileum structure impairment, increased proinflammatory cytokines and intestinal epithelial cell (IEC) necroptosis, and PS-COOH/PS-NH₂ NPs exhibited higher adverse effects on ileum tissues. Furthermore, we found PS-NPs induced necroptosis rather than apoptosis via activating RIPK3/MLKL pathway in IECs. Mechanistically, we found that PS-NPs accumulated in the mitochondria and subsequently caused mitochondrial stress, which initiated PINK1/Parkin-mediated mitophagy. However, mitophagic flux was blocked due to lysosomal deacidification caused by PS-NPs, and thus led to IEC necroptosis. We further found that mitophagic flux recovery by rapamycin can alleviate NP-induced IEC necroptosis. Our findings revealed the underlying mechanisms concerning NP-triggered Crohn's ileitis-like features and might provide new insights for the further safety assessment of NPs.

Effects of true-to-life PET nanoplastics using primary human nasal epithelial cells

Since inhalation is a relevant exposure route, studies using appropriate micro/nanoplastic (MNPLs) models, representative targeted cells, and relevant biomarkers of effect are required. We have used lab-made polyethylene terephthalate (PET)NPLs obtained from PET plastic water bottles. Human primary nasal epithelial cells (HNEpCs) were used as a model of the first barrier of the respiratory system. Cell internalization and intracellular reactive oxygen species (iROS) induction, as well as the effects on mitochondria functionality and in the modulation of the autophagy pathway, were evaluated. The data indicated significant cellular uptake and increased levels of iROS. Furthermore, a loss of mitochondrial membrane potential was observed in the exposed cells. Regarding the effects on the autophagy pathway, PETNPLs exposure significantly increases LC3-II protein expression levels. PETNPLs exposure also induced significant increases in the expression of p62. This is the first study showing that true-to-life PETNPLs can alter the autophagy pathway in HNEpCs.

Maltol attenuates polystyrene nanoplastic-induced enterotoxicity by promoting AMPK/mTOR/TFEB-mediated autophagy and modulating gut microbiota

The production and application of nanoplastics has been increased during decades, and the enterotoxicity caused by their bioaccumulation has attracted vast attention. Maltol was proved to exert a protective effect on gut damage induced by carbon tetrachloride and cisplatin, indicating its confrontation with nanoplastics-induced intestinal toxicity. To explore the ameliorative effects of maltol on polystyrene nanoplastics (PS)-mediated enterotoxicity and the underlying mechanism, the mice were exposed to PS (100 mg/kg), combining with or without the treatment of maltol treatment at 50 and 100 mg/kg. We found PS exposure caused intestinal barrier damage and enterocyte apoptosis, while lysosomal dysfunction and autophagic substrate degradation arrest in enterocytes of mice were also observed. In addition, PS exacerbated the disturbance of the intestinal microbial community, affected the abundance of lysosome and apoptosis-related bacterial genes, and decreased the number of known short-chain fatty acid (SCFA) producing bacteria. However, those alterations were improved by the maltol treatment. Maltol also protected the human intestinal Caco-2 cells from PS-induce damages. Mechanistic studies showed maltol promoted TFEB nuclear translocation through the AMPK/mTOR signaling pathway to restore lysosomal function and reduce autophagy dependent apoptosis. The findings in the present work might help to elucidate the potential molecular mechanisms of PS-induced enterotoxicity. For the first time to our knowledge, the protective effect of maltol on PS-induced intestinal injury was studied from multiple perspectives, which provided a potential therapeutic approach for diseases caused by environmental pollution.

Cellular absorption of polystyrene nanoplastics with different surface functionalization and the toxicity to RAW264.7 macrophage cells

Nanoplastics (NPs) are a matter of widespread concern, as they are easily absorbed by a wide variety of organisms and accumulate in biological tissues. While there is evidence that nanoplastics are toxic to various organisms, few studies have investigated the mechanisms underlying the toxicities of NPs with different surface functionalizations to macrophage cells. In this study, mouse mononuclear macrophage (RAW264.7) cells were exposed to polystyrene nanoplastics (PS-NPs) with three different surface functionalizations, namely pristine polystyrene (PS), carboxyl-functionalized polystyrene (PS-COOH), and amino-functionalized polystyrene (PS-NH₂), to evaluate the cellular endocytosis, lactate dehydrogenase (LDH) release, cell viability, reactive oxygen species (ROS), mitochondrial membrane potential, apoptosis, and related gene expression. Results showed that all three PS-NPs were endocytosed into cells. However, in the concentration range of 0-100 μg/mL, PS had no effect on cell viability or apoptosis, but it slightly increased cellular ROS and decreased mitochondrial membrane potential. PS-NH₂ exhibited the highest cytotoxicity. PS-COOH and PS-NH₂ induced ROS production, altered the mitochondrial membrane potential, and caused cell apoptosis regulated by the mitochondrial apoptosis pathway. Results also showed that cell membrane damage induced by PS-NH₂ is one of the primary mechanisms of its cytotoxicity to RAW264.7 cells. The results of this study clarify the toxicities of PS-NPs with different surface functionalizations to macrophages, thereby improving the identification of immune system risks related to nanoplastics.

An integrative method for evaluating the biological effects of nanoparticle-protein corona

BACKGROUND

Nanoplastics in the environment can enter the human body through gastrointestinal intake, dermal contact, and pulmonary inhalation, posing a threat to human health. Protein molecules in body fluids will quickly adsorb on the surfaces of the nanoplastics, forming a protein corona, which has implications for the interaction of the nanoplastics with cells and the metabolic pathways of the nanoplastic within cells. For years, practical tools such as dynamic light scattering, transmission electron microscopy, and liquid chromatography have been developed to understand the protein corona of nanoparticles (NPs), either in vitro or in cellular or molecular level. However, an integrated approach to understand the nanoparticles-protein corona is still lacking.

METHODS

Using the most frequently observed environmental nanoplastics, polystyrene nanoplastics (PS), as a standard, we established an integrative structural characterization platform, a biophysical and biochemical evaluation method to investigate the effect of surface charge on protein corona composition. The cellular and molecular mechanisms were also explored through in vitro cellular experiments.

RESULTS

The first integrative method for characterizing biological properties of NPs-protein corona has been established. This method comprehensively covers the critical aspects to understand NPs-protein corona interactions, from structure to function.

CONCLUSIONS

The integrative method for nanoplastics microstructure characterization can be applied to the structural characterization of nanoparticles in nanoscale, which is of universal significance from in vitro characterization to cellular experiments and then to molecular mechanism studies.

GENERAL SIGNIFICANCE

This strategy has high reliability and repeatability and can be applied both in environment and nanomedicine safety assessment.

Assessing the Mass Concentration of Microplastics and Nanoplastics in Wastewater Treatment Plants by Pyrolysis Gas Chromatography-Mass Spectrometry

The level of microplastics (MPs) in wastewater treatment plants (WWTPs) has been well evaluated by the particle number, while the mass concentration of MPs and especially nanoplastics (NPs) remains unclear. In this study, pyrolysis gas chromatography-mass spectrometry was used to determine the mass concentrations of MPs and NPs with different size ranges (0.01-1, 1-50, and 50-1000 μm) across the whole treatment schemes in two WWTPs. The mass concentrations of total MPs and NPs decreased from 26.23 and 11.28 μg/L in the influent to 1.75 and 0.71 μg/L in the effluent, with removal rates of 93.3 and 93.7% in plants A and B, respectively. The proportions of NPs (0.01-1 μm) were 12.0-17.9 and 5.6-19.5% in plants A and B, respectively, and the removal efficiency of NPs was lower than that of MPs (>1 μm). Based on annual wastewater effluent discharge, it is estimated that about 0.321 and 0.052 tons of MPs and NPs were released into the river each year. Overall, this study investigated the mass concentration of MPs and NPs with a wide size range of 0.01-1000 μm in wastewater, which provided valuable information regarding the pollution level and distribution characteristics of MPs, especially NPs, in WWTPs.

Aging of Nanoplastics Significantly Affects Protein Corona Composition Thus Enhancing Macrophage Uptake

Nanoplastics (NPs), as emerging contaminants, have attracted increasing attention for their effects on human exposure and potential health risks. The protein corona formed on the surface of NPs affects the biological activity and fate of the NPs in vivo. However, how environmental aging, an inevitable process once NPs enter the environment, affects the formation of protein corona on NPs is still unclear. This study investigated the changes in the compositions of protein corona formed on photo-aged polystyrene (PS) NPs in human bronchoalveolar lavage fluid (BALF), corresponding to the inhalation exposure pathway. The results demonstrated that both the species and abundance of proteins in the BALF protein corona on the surface of PS NPs were altered by aging. In addition, the aged PS NPs are more hydrophilic and less electronegative than the pristine PS NPs; hence, there is an increased sorption of more negatively charged hydrophilic proteins. Moreover, aging-induced alterations in BALF protein corona enhanced the uptake of aged PS NPs by lung macrophages J774A.1 through phagocytosis and clathrin-mediated endocytosis. These findings highlight the importance of environmental aging processes in the biosafety assessment of nanoplastics.

Internalization and cytotoxicity of polystyrene microplastics in human umbilical vein endothelial cells

Ubiquitous micro(nano)plastics (MNPs) are emerging environmental pollutants, which pose a potential threat to human health. When MNPs enter the blood circulatory system, vascular endothelium is one of the most important target organs that directly interact with the MNPs. However, little is known about the cytotoxicity of MNPs to vascular endothelial cells. In this study, we investigated the uptake and cytotoxic effects of polystyrene MNPs with a particle size of 1 μm (1-μm PS-MNPs) on human umbilical vein endothelial cells (HUVECs) in vitro. Our study found that interaction between HUVECs and 1-μm PS-MNPs was at a very low level. Even at the high exposure concentration of 25 μg/mL, the percentage of HUVECs combined with fluorescent 1-μm PS-MNPs was only 3.80% using flow cytometry analysis. Moreover, there were no significant differences in inflammation, autophagy, reactive oxygen species (ROS) level, lactate dehydrogenase (LDH) release, and adhesion molecule expression following exposure to 1-μm PS-MNPs (5, 10, and 25 μg/mL) for 48 h, except for a remarkable decrease in cell viability at the extremely high concentration of 100 μg/mL. Herein, 1-μm PS-MNPs showed a low level of acute toxicity to HUVECs in vitro, and we expect these results contribute to the further risk assessment of MNPs on human health.

Hazard Assessment of Polystyrene Nanoplastics in Primary Human Nasal Epithelial Cells, Focusing on the Autophagic Effects

The human health risks posed by micro/nanoplastics (MNPLs), as emerging pollutants of environmental/health concern, need to be urgently addressed as part of a needed hazard assessment. The routes of MNPL exposure in humans could mainly come from oral, inhalation, or dermal means. Among them, inhalation exposure to MNPLs is the least studied area, even though their widespread presence in the air is dramatically increasing. In this context, this study focused on the potential hazard of polystyrene nanoplastics (PSNPLs with sizes 50 and 500 nm) in human primary nasal epithelial cells (HNEpCs), with the first line of cells acting as a physical and immune barrier in the respiratory system. Primarily, cellular internalization was evaluated by utilizing laboratory-labeled fluorescence PSNPLs with iDye, a commercial, pink-colored dye, using confocal microscopy, and found PSNPLs to be significantly internalized by HNEpCs. After, various cellular effects, such as the induction of intracellular reactive oxygen species (iROS), the loss of mitochondrial membrane potential (MMP), and the modulation of the autophagy pathway in the form of the accumulation of autophagosomes (LC3-II) and p62 markers (a ubiquitin involved in the clearance of cell debris), were evaluated after cell exposure. The data demonstrated significant increases in iROS, a decrease in MMP, as well as a greater accumulation of LC3-II and p62 in the presence of PSNPLs. Notably, the autophagic effects did indicate the implications of PSNPLs in defective or insufficient autophagy. This is the first study showing the autophagy pathway as a possible target for PSNPL-induced adverse effects in HNEpCs. When taken together, this study proved the cellular effects of PSNPLs in HNEpCs and adds value to the existing studies as a part of the respiratory risk assessment of MNPLs.

MTX-PEG-modified CG/DMMA polymeric micelles for targeted delivery of doxorubicin to induce synergistic autophagic death against triple-negative breast cancer

The chemotherapy of triple-negative breast cancer based on doxorubicin (DOX) regimens suffers from great challenges on toxicity and autophagy raised off-target. In this study, a conjugate methotrexate-polyethylene glycol (shorten as MTX-PEG)-modified CG/DMMA polymeric micelles were prepared to endue DOX tumor selectivity and synergistic autophagic flux interference to reduce systematic toxicity and to improve anti-tumor capacity. The micelles could effectively promote the accumulation of autophagosomes in tumor cells and interfere with the degradation process of autophagic flux, collectively inducing autophagic death of tumor cells. In vivo and in vitro experiments showed that the micelles could exert improved anti-tumor effect and specificity, as well as reduced accumulation and damage of chemotherapeutic drugs in normal organs. The potential mechanism of synergistic autophagic death exerted by the synthesized micelles in MDA-MB-231 cells has been performed by autophagic flux-related pathway.

Autophagic response of intestinal epithelial cells exposed to polystyrene nanoplastics

Growing evidence demonstrates that the bioaccumulation of polystyrene nanoplastics (PS-NPs) in the gastrointestinal tract has negative effects on health. Until now, little information has been available regarding the potential hazards of PS-NPs to intestinal epithelial barriers. In this study, we employed cellular and animal models to investigate the adverse effects of PS-NPs on intestinal epithelium and the underlying mechanism. We found that PS-NPs affected the growth and survival of intestinal epithelial cells in a time- and concentration-dependent manner. PS-NPs accumulated in the cytoplasm, resulting in an impaired autophagic flux and inducing an autophagic response. This response was also confirmed in vivo. Our results provide new insights into the internalization of PS-NPs and the resultant autophagy response in intestinal epithelial cells.

Responses of zebrafish (Danio rerio) cells to antibiotic erythromycin stress at the subcellular levels

Erythromycin (ERY) is one of the most used antibiotics frequently detected in different aquatic environments and may bring burdens to aquatic ecosystems. However, the impacts of antibiotics on aquatic systems other than the antibiotic resistance genes remain largely unknown. In the present study, the responses to ERY exposure at the subcellular-organelle levels were for the first time investigated and imaged over 24 h. Exposure to ERY hampered the zebrafish (Danio rerio) cell growth and decreased the cell viability in a time-dependent mode. Meanwhile, exposure to a low concentration of ERY (73.4 μg L^-1) induced reactive oxygen species (ROS) overproduction and lysosomal damage following lysosomal alkalization and swelling. In turn, the lysosomal stress was the major driver of altering the ROS level, superoxide dismutase (SOD) activity, and glutathione (GSH) content. Subsequently, mitochondria displayed dysfunction such as increased mitochondrial ROS, impaired mitophagy, and induced mitochondria-driven apoptosis, as well as impaired mitochondrial electron transport chain and loss of membrane potential. These results collectively demonstrated the subcellular sensitive machinery responses to ERY stress at environmentally relevant and slightly higher sub-lethal concentrations. ERY may induce switching from autophagy to apoptosis with corresponding changes in lysosomal activity, antioxidant activity, and mitochondrial activity. The findings provided important information on the physiological and subcellular responses of fish cells to ERY.

A Nanomedicine Structure-Activity Framework for Research, Development, and Regulation of Future Cancer Therapies

Despite their clinical success in drug delivery applications, the potential of theranostic nanomedicines is hampered by mechanistic uncertainty and a lack of science-informed regulatory guidance. Both the therapeutic efficacy and the toxicity of nanoformulations are tightly controlled by the complex interplay of the nanoparticle's physicochemical properties and the individual patient/tumor biology; however, it can be difficult to correlate such information with observed outcomes. Additionally, as nanomedicine research attempts to gradually move away from large-scale animal testing, the need for computer-assisted solutions for evaluation will increase. Such models will depend on a clear understanding of structure-activity relationships. This review provides a comprehensive overview of the field of cancer nanomedicine and provides a knowledge framework and foundational interaction maps that can facilitate future research, assessments, and regulation. By forming three complementary maps profiling nanobio interactions and pathways at different levels of biological complexity, a clear picture of a nanoparticle's journey through the body and the therapeutic and adverse consequences of each potential interaction are presented.

Potential Artifacts and Control Experiments in Toxicity Tests of Nanoplastic and Microplastic Particles

To fully understand the potential ecological and human health risks from nanoplastics and microplastics (NMPs) in the environment, it is critical to make accurate measurements. Similar to past research on the toxicology of engineered nanomaterials, a broad range of measurement artifacts and biases are possible when testing their potential toxicity. For example, antimicrobials and surfactants may be present in commercially available NMP dispersions, and these compounds may account for toxicity observed instead of being caused by exposure to the NMP particles. Therefore, control measurements are needed to assess potential artifacts, and revisions to the protocol may be needed to eliminate or reduce the artifacts. In this paper, we comprehensively review and suggest a next generation of control experiments to identify measurement artifacts and biases that can occur while performing NMP toxicity experiments. This review covers the broad range of potential NMP toxicological experiments, such as in vitro studies with a single cell type or complex 3-D tissue constructs, in vivo mammalian studies, and ecotoxicity experiments testing pelagic, sediment, and soil organisms. Incorporation of these control experiments can reduce the likelihood of false positive and false negative results and more accurately elucidate the potential ecological and human health risks of NMPs.