Synergistic impact of nanoplastics and nanopesticides on Artemia salina and toxicity analysis.

Polystyrene nanoplastics (PSNPs) when exposed to nanopermethrin (NPER) exacerbate toxicity on Artemia salina. In the environment, NPs act as a vector for other pollutants mainly heavy metals and pesticides. Nanopesticides are efficient compared to their bulk form. The adsorption of NPER on PSNPs was studied systematically and it was found that the binding of NPER is inversely proportional to its concentration. NPER adsorption on PSNPs followed pseudo-first-order kinetics with an adsorption percentage of 1.7%, 3.7%, 7.7%, 15.4%, and 30.8% when PSNPs were incubated with 2 mg L-1,4 mg L-1, 8 mg L-1, 16 mg L-1, and 32 mg L-1 of NPER. The adsorption followed the Langmuir isotherm. The increased hydrodynamic size of the NPER/PSNP complex was observed. Different characterization studies were performed for NPER, PSNPs, and their complex using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, and gas chromatography-mass spectrometry. The LC50 value for the NPER/PSNP complex treated with Artemia salina was 3.127 mg L-1, compared to LC50 NPER which was found to be 4.536 mg L-1. PSNPs had a lower mortality rate in Artemia salina, where 50% mortality (LC50) was not observed at their working concentration. Both the nanoforms led to morphological changes in Artemia salina. Reactive oxygen species increased to 87.94% for the NPER/PSNP complex, 78.93% for NPER, and 23.65% for PSNPs. Greater amounts of ROS in the cells may have led to SOD degradation. Superoxide dismutase activity for the NPER/PSNP complex was 1.2 U mg-1, NPER was 1.3 U mg-1, and PSNPs was 2.1 U mg-1. A lipid peroxidation study reveals that the melondialdehyde synthesis by NPER/PSNPs complex, NPER and PSNPs were found to be 2.21 nM mg-1, 1.59 nM mg-1, and 0.91 nM mg-1 respectively. Catalase activity in a complex of NPER/PSNPs, NPER, and PSNPs was found to be 1.25 U mg-1, 0.94 U mg-1, and 0.49 U mg-1. This study envisages the individual and combined toxicity of nanopesticides and PSNPs on aquatic organisms. Increased plastic usage and new-age chemicals for agriculture could result in the formation of a PSNPs-NPER complex potentially causing highly toxic effects on aquatic animals, compared to their pristine forms. Therefore, we should also consider the other side of nanotechnology in agriculture.

Surface functionalization, particle size and pharmaceutical co-contaminant dependent impact of nanoplastics on marine crustacean - Artemia salina.

Despite a significant amount of research on micronanoplastics (MNPs), there is still a gap in our understanding of their function as transporters of other environmental pollutants (known as the Trojan horse effect) and the combined effects of ingestion, bioaccumulation, and toxicity to organisms. This study examined the individual effects of polystyrene nanoplastics (PSNPs) with various surface functionalizations (plain (PS), carboxylated (PS-COOH), and aminated (PS-NH2)), particle sizes (100 nm and 500 nm), and a pharmaceutical co-contaminant (metformin hydrochloride (MH), an anti-diabetic drug) on the marine crustacean - Artemia salina. The study specifically aimed to determine if MH alters the detrimental effects of PSNPs on A. salina. The potential toxicity of these emerging pollutants was assessed by examining mortality, hatching rate, morphological changes, and biochemical changes. Smaller nanoparticles had a more significant impact than larger ones, and PS-NH2 was more harmful than PS and PS-COOH. Exposure to the nanoparticle complex with MH resulted in a decrease in hatching rate, an increase in mortality, developmental abnormalities, an increase in reactive oxygen species, catalase, and lipid peroxidase, and a decrease in total protein and superoxide dismutase, indicating a synergistic effect. There were no significant differences between the complex and the individual nanoparticles. However, accumulating these particles in organisms could contaminate the food chain. These results highlight the potential environmental risks associated with the simultaneous exposure of aquatic species to plastics, particularly smaller PS, aminated PS, and pharmaceutical complex PS.

Surface interaction of vancomycin with polystyrene microplastics and its effect on human serum albumin.

Microplastics have a well-documented ability to adsorb various chemicals and contaminants found in the environment. By similar mechanisms, when medicines are stored in plastic packaging, the leaching of plastics into the contents poses the risk of possible toxicity and decreased drug efficacy. The work thus examines the presence of two categories of anthropogenic materials - microplastics (MPs) and medications - with their possible combined effects and fate in biological systems. A study on the kinetics and isotherm of the adsorption of vancomycin hydrochloride on the surface of polystyrene microspheres is performed, and the best-fitting models are obtained respectively as the pseudo-second-order model and the Temkin isotherm. Further, the interaction of each of, the drug, MPs and drug-adsorbed MPs with human serum albumin (HSA), the model protein chosen to validate the potential toxicity in humans, is determined by fluorescence spectroscopy. A thermodynamic analysis of this protein-ligand interaction shows that the process is spontaneous, endothermic and entropically favoured, and that hydrophobic forces operate between the interacting species. An unfolding of HSA is observed, disrupting its functions like the esterase activity. Competitive binding experiments with Warfarin and Ibuprofen as specific site markers on HSA reveal that all the studied ligands bind non-specifically to HSA.

Assessment of polystyrene nano plastics effect on human salivary α-amylase structural alteration: Insights from an in vitro and in silico study.

The study found that the enzyme activity of human salivary α-amylase (α-AHS) was competitively inhibited by nanoplastic polystyrene (PS-NPs), with a half-inhibitory concentration (IC50) of 92 µg/mL, while the maximum reaction rate (Vmax) remained unchanged at 909 µg/mL•min. An increase in the concentration of PS-NPs led to a quenching of α-AHS fluorescence with a slight red shift, indicating a static mechanism. The binding constant (Ka) and quenching constant (Kq) were calculated to be 2.92 × 1011 M-1 and 1.078 × 1019 M-1• S-1 respectively, with a hill coefficient (n) close to one and an apparent binding equilibrium constant (KA) of 1.54 × 1011 M-1. Molecular docking results suggested that the interaction between α-AHS and PS-NPs involved π-anion interactions between the active site Asp197, Asp300 residues, and van der Waals force interactions affecting the Tyr, Trp, and other residues. Fourier transform infrared (FT-IR) and circular dichroism (CD) analyses revealed conformational changes in α-AHS, including a loss of secondary structure α-helix and ß-sheet. The study concludes that the interaction between α-AHS and PS-NPs leads to structural and functional changes in α-AHS, potentially impacting human health. This research provides a foundation for further toxicological analysis of MPs/NPs in the human digestive system.

Unveiling the Modification of Esterase-like Activity of Serum Albumin by Nanoplastics and Their Cocontaminants.

Nanoplastics and other cocontaminants have raised concerns due to their widespread presence in the environment and their potential to enter the food chain. The harmful effects of these particles depend on various factors, such as nanoparticle size, shape, surface charge, and the nature of the cocontaminants involved. On entering the human body, human serum albumin (HSA) molecules bind and transport these particles in the blood system. The esterase-like activity of HSA, which plays a role in metabolizing drug/toxic compounds, was taken as a representative to portray the effects of these particles on HSA. Polystyrene nanoplastics (PSNPs) with different surface functionalization (plain (PS), amine (PS-NH2), and carboxy (PS-COOH)), different sizes (100 and 500 nm), and PS with cocontaminant metformin hydrochloride (Met-HCl), a widely used antidiabetic drug, were investigated in this study. Fluorescence emission spectra of HSA revealed that PS-NH2 exhibits a greater effect on protein conformation, smaller NPs have a greater influence on protein structure than larger NPs, and Met-HCl lowers PSNPs' affinity for HSA by coating the surface of the NPs, which may result in direct NP distribution to the drug's target organs and toxicity. Circular dichroism spectra also supported these results in terms of secondary structural changes. Esterase activity of HSA was inhibited by all the particles (except Met-HCl) by competitive inhibition as concluded from constant Vmax and increasing Km. Greater reduction in enzyme activity was observed for PS-NH2 among functionalizations and for 100 nm PS among sizes. Furthermore, Met-HCl lowers the inhibitory impact of PSNPs on HSA since the drug binds weakly to HSA, and so they can serve as a vector delivering PSNPs to their target organs, resulting in serious implications.

Journey of micronanoplastics with blood components.

The entry of micro- and nanoplastics (MNPs) into the human body is inevitable. They enter blood circulation through ingestion, inhalation, and dermal contact by crossing the gut-lung-skin barrier (the epithelium of the digestive tract, the respiratory tract, and the cutaneous layer). There are many reports on their toxicities to organs and tissues. This paper presents the first thorough assessment of MNP-driven bloodstream toxicity and the mechanism of toxicity from the viewpoint of both MNP and environmental co-pollutant complexes. Toxic impacts include plasma protein denaturation, hemolysis, reduced immunity, thrombosis, blood coagulation, and vascular endothelial damage, among others, which can lead to life-threatening diseases. Protein corona formation, oxidative stress, cytokine alterations, inflammation, and cyto- and genotoxicity are the key mechanisms involved in toxicity. MNPs change the secondary structure of plasma proteins, thereby preventing their transport functions (for nutrients, drugs, oxygen, etc.). MNPs inhibit erythropoiesis by influencing hematopoietic stem cell proliferation and differentiation. They cause red blood cell and platelet aggregation, as well as increased adherence to endothelial cells, which can lead to thrombosis and cardiovascular disease. White blood cells and immune cells phagocytose MNPs, provoking inflammation. However, research gaps still exist, including gaps regarding the combined toxicity of MNPs and co-pollutants, toxicological studies in human models, advanced methodologies for toxicity analysis, bioaccumulation studies, inflammation and immunological responses, dose-response relationships of MNPs, and the effect of different physiochemical characteristics of MNPs. Furthermore, most studies have analyzed toxicity using prepared MNPs; hence, studies must be undertaken using true-to-life MNPs to determine the real-world scenario. Additionally, nanoplastics may further degrade into monomers, whose toxic effects have not yet been explored. The research gaps highlighted in this review will inspire future studies on the toxicity of MNPs in the vascular/circulatory systems utilizing in vivo models to enable more reliable health risk assessment.

Interaction of antidiabetic formulation with nanoplastics and its binary influence on plasma protein.

Nanoplastics exposure to humans becomes inevitable due to its prevalence and permanence. Adsorption of emerging pollutant metformin hydrochloride (Met-HCl) -antidiabetic drug, on polystyrene nanoplastics (PSNPs) and influence on plasma protein binding was investigated. Fluorescence studies were carried out for human serum albumin (HSA) binding. Adsorption follows pseudo-second-order kinetics, intraparticle-diffusion, and Langmuir isotherm, undergoing both physisorption and chemisorption which was validated by FE-SEM, FTIR, and HRMS measurements. Complex, experiences static quenching mechanism by hydrogen bonding and VanderWaals force of attraction to HSA. FTIR confirms the secondary structural alteration of HSA. Since Met-HCl covers the NPs' surface, NPs' affinity for HSA is reduced and they might reach the target organs of Met-HCl, disrupt antidiabetic mechanisms and cause far-reaching implications. Results from molecular docking and simulation studies backed up these results as hydrophobic and hydrogen bonds dominate the binding process of the HSA-Met-HCl-PSNPs complex. This work will aid in understanding of the toxico-kinetics/dynamics of binary contaminants.

Molecular Interaction of Functionalized Nanoplastics with Human Hemoglobin.

Humans are exposed to excessive nanoplastics (NPs) which have ample affinity for globular proteins. We investigated the interaction of functionalized polystyrene nanoplastics (plain: PS, carboxy: PS-COOH, and amine: PS-NH2) with human hemoglobin (Hb) utilizing multi-spectroscopic and docking approaches to acquire insights into molecular aspects of binding mechanism, which will be helpful in assessing the toxicokinetics or toxicodynamics of nanoplastics NPs. Hypsochromicity and hypochromicity were observed invariably in all the spectra (steady-state fluorescence emission, synchronous and three-dimensional) for all complexes, among which PS-NH2 binds effectively and changes the Hb's conformation by enhancing hydrophobicity around aromatic residues, notably tryptophan. All the NPs bind with the hydrophobic pocket of B-chain in Hb, where PS and PS-NH2 bind via hydrophobic force while PS-COOH binds via hydrogen bonding (predominantly) and van der Waals force, consistent validated with docking results. The minimal shift in absorbance peak also indicates enhanced hydrophobicity by PS-NH2 with larger aggregation as demonstrated in resonance light scattering. The amide band's shift, secondary structural analysis, and presence of characteristic functional group peaks in complexes in Infra-Red spectra confirm the structural changes in the protein. As seen in field emission scanning microscopy images, NPs penetrate the surface of proteins. These findings conclude that polystyrene NPs interact with Hb, causing structural alterations that may affect functional characteristics as well, with the greatest effect being in the order: PS-NH2>PS-COOH>PS.

Nanoplastics alter the conformation and activity of human serum albumin.

Nanoplastics finds its presence in most of the consumer products. Their chance of coming in contact with human cells and components is rampant. This study focuses on the interaction of polystyrene nanoplastics (PSNPs) with human serum albumin (HSA), ultimately causing structural and functional properties of the protein. Fluorescence and UV-Visible spectroscopic studies reported that PSNPs form a spontaneous ground-state complex with HSA, by hydrogen bonding, van der waal's, and hydrophobic force of attraction. This causes changes in the environment around major aromatic amino acids, especially tryptophan-214, which has a strong affinity with PSNPs. Further docking analysis confirmed hydrophobic interactions between PSNPs and aromatic amino acids in subdomain IIA of HSA. A shift in amide bands in HSA, as determined by FTIR analysis confirmed the disturbances in its secondary structure followed by reordering which will lead to the unfolding of HSA. Besides, PSNPs reduce the esterase activity of HSA by competitive inhibition. This molecular-level information such as binding energy, binding site, binding forces, reversible or irreversible binding, and structural changes of protein will shed light on the extent of toxicity in humans. This study will emphasize the urgent need for regulation of the use of nanoplastics (NPs) in consumer products, as well as the need for more research to determine the fate of NPs in the biological system.

Repeated oral dose toxicity study on hydrolysable tannin rich fraction isolated from fruit pericarps of Terminalia chebula Retz in Wistar albino rats.

Terminalia chebula fruits are one of the richest sources of hydrolysable tannins and it is well known medicinal agent in traditional systems of medicine for treatment of various chronic ailments. In the present study, hydrolysable tannin rich fraction (HTF) was isolated from 80% hydroalcoholic extract of Terminalia chebula fruit pericarps and it was studied for acute and repeated dose oral toxicity in Wistar albino rats. HTF did not show any toxic symptoms or mortality at single dose administration of 5000 mg/kg/p.o followed by observation for 14 days. On repeated dose 28 days oral toxicity study, administration of HTF at 1000 mg/kg showed marked reduction in body weight, food intake and water intake when compared with vehicle control. It was also observed that HTF could increase serum urea, glucose and AST level significantly when compared with vehicle control indicating mild disturbances in liver and kidney functions. On histopathological screening, HTF treatment showed a mild granulomatous inflammation in the liver and all other organs remained normal. It was concluded that following 28 days repeated dose oral administration, HTF caused mild disturbances in liver and kidney function which was indicated by reduced body weight, food and water intake, serum parameters and histological observations.