Insights into the toxicity of biomaterials microparticles with a combination of cellular and oxidative biomarkers

The unheeded inherent connections and overlap between microplastics and poly- and perfluoroalkyl substances: A comprehensive review

Microplastics (MPs) and poly- and perfluoroalkyl substances (PFASs) are receiving global attention due to their widespread presences and considerable level in the environment. Although the occurrence and fate of MPs and PFASs alone have been extensively studied, little was known about their unheeded connection and overlap between the two. Therefore, this review attempts to reveal it for the purpose of providing a new view from joint consideration of the two in the future studies. Initially, the critically examined data on the co-sources and existence of MPs and PFASs are summarized. Surprisingly, some products could be co-source of MPs and PFASs which are general in daily life while the distribution of the two is primary influenced by the human activity. Then, their interactions are reviewed based on the fact that PFASs can be sorbed onto MPs which are regarded as a vector of contaminations. The electrostatic interaction and hydrophobic contact are the predominant sorption mechanisms and could be influenced by environmental factors and properties of MPs and PFASs. The effects of MPs on the transport of PFASs in the environments, especially in aquatic environments are then discussed. Additionally, the current state of knowledge on the combined toxicity of MPs and PFASs are presented. Finally, the existing problems and future perspectives are outlined at the end of the review. This review provides an advanced understanding of the overlap, interaction and toxic effects of MPs and PFASs co-existing in the environment.

Covalent organic frameworks (COFs) and metal-organic frameworks (MOFs) as electrochemical sensors for the efficient detection of pharmaceutical residues

Pharmaceutical residues are the undecomposed remains from drugs used in the medical and food industries. Due to their potential adverse effects on human health and natural ecosystems, they are of increasing worldwide concern. The acute detection of pharmaceutical residues can give a rapid examination of their quantity and then prevent them from further contamination. Herein, this study summarizes and discusses the most recent porous covalent-organic frameworks (COFs) and metal-organic frameworks (MOFs) for the electrochemical detection of various pharmaceutical residues. The review first introduces a brief overview of drug toxicity and its effects on living organisms. Subsequently, different porous materials and drug detection techniques are discussed with materials' properties and applications. Then the development of COFs and MOFs has been addressed with their structural properties and sensing applications. Further, the stability, reusability, and sustainability of MOFs/COFs are reviewed and discussed. Besides, COFs and MOFs' detection limits, linear ranges, the role of functionalities, and immobilized nanoparticles are analyzed and discussed. Lastly, this review summarized and discussed the MOF@COF composite as sensors, the fabrication strategies to enhance detection potential, and the current challenges in this area.

Polysaccharide Nanofiber-Stabilized Pickering Emulsion Microparticles Induce Pyroptotic Cell Death in Hepatocytes and Kupffer Cells

The intracellular uptake and interaction behavior of emulsion microparticles in liver cells critical to host defense and inflammation is significant to understanding their potential cytotoxicity and biomedical applications. In this study, the cell death responses of fibroblastic, hepatocyte, and Kupffer cells (KCs) induced by four types of emulsion particles that are stabilized by polysaccharide nanofibers (cellulose or chitin), an inorganic nanoparticle (β-tricalcium phosphate), or surfactants are compared. Pickering emulsion (PE) microparticles stabilized by polysaccharide nanofibers or inorganic nanoparticles have a droplet size of 1-3 µm, while the surfactant-stabilized emulsion has a diameter of ≈190 nm. Polysaccharide nanofiber-stabilized PEs (PPEs) markedly induce lactate dehydrogenase release in all cell types. Additionally, characteristic pyroptotic cell death, which is accompanied by cell swelling, membrane blebbing, and caspase-1 activation, occurs in hepatocytes and KCs. These PE microparticles are co-cultured with lipopolysaccharide-primed KCs associated with cytokine interleukin-1β release, and the PPEs demonstrate biological activity as a mediator of the inflammation response. Well-designed PPE microparticles induce pyroptosis of liver cells, which may provide new insight into regulating inflammation-related diseases for designing potent anticancer drugs and vaccine adjuvants.

Recent Advances in the Investigation of Poly(lactic acid) (PLA) Nanocomposites: Incorporation of Various Nanofillers and their Properties and Applications

Poly(lactic acid) (PLA) is considered the most promising biobased substitute for fossil-derived polymers due to its compostability, biocompatibility, renewability, and good thermomechanical properties. However, PLA suffers from several shortcomings, such as low heat distortion temperature, thermal resistance, and rate of crystallization, whereas some other specific properties, i.e., flame retardancy, anti-UV, antibacterial or barrier properties, antistatic to conductive electrical characteristics, etc., are required by different end-use sectors. The addition of different nanofillers represents an attractive way to develop and enhance the properties of neat PLA. Numerous nanofillers with different architectures and properties have been investigated, with satisfactory achievements, in the design of PLA nanocomposites. This review paper overviews the current advances in the synthetic routes of PLA nanocomposites, the imparted properties of each nano-additive, as well as the numerous applications of PLA nanocomposites in various industrial fields.

Do poly(lactic acid) microplastics instigate a threat? A perception for their dynamic towards environmental pollution and toxicity

Fears concerning microplastics (MPs) environmental fate and persistence are progressively expanding on a global basis, with the emphasis given to manufacturing bioplastics for substituting petro-derived plastics extensively growing. Among them, poly(lactic acid) (PLA) holds a pioneering role towards the replacement of conventional polymeric materials, owing to its multifunctional properties, enclosing superior mechanical properties, low cost, renewability, great biocompatibility, transparency, and thermoplasticity launching many fields of application. Due to the wide applicability of PLA in several sectors of everyday life, its waste to be released into the environment is expected to follow a growing tendency during the upcoming years. Even though PLA is a biodegradable polyester, it actually degrades under specific composting environments, including a rich oxygen environment with high temperatures (58-80 °C), high humidity (>60% moisture) as well as the presence of micro-organisms (thermophilic bacteria). Additionally, in various studies it has been implied that PLA displays slower degradation performance when found in blends with other conventional polymers, underlining the unspecified effects on PLA degradation profile, keeping thus the information about PLA degradation from a blur standpoint. Therefore, a deepened understanding of the fate and dynamic effects of PLA MPs is of primary importance. Nevertheless, the current examination of the effects of PLA MPs in terms of sorption capacities and toxicity is so far limited and broadly unexplored since the current scientific emphasis has been merely centered on the conventional MPs' behavior. In this light, the present review provides an inclusive overview of the ongoing research of poly(lactic acid) in the framework of microplastics' pollution, while the future trends and missing points in this context are highlighted.

Differentiation in the expression of toxic effects of polyethylene-microplastics on two freshwater fish species: Size matters

The built up of microplastic (MPs) remains is shaping a new aquatic habitat and imposes the necessity for research of the effects that these relatively new pollutants exert on organisms, environment, and human health. The purpose of the present study was to verify if there is a particle-size dependence of fish response to MPs. Thus, we exposed two freshwater fish species, the zebrafish (Danio rerio) and perch (Perca fluviatilis) for 21 days to polyethylene microplastics (PE-MPs) sized 10-45 μm and 106-125 μm. Thereafter, in the liver and gills tissues, biochemical and molecular parameters and the metabolic profile were examined. Ex-vivo characterization by ATR-FTIR spectroscopy exhibited increased concentration of 10-45 μm PE-MPs in the liver of the two fish species while 106-125 μm PE-MPs mostly concentrated in fish gills. The penetration of PE-MPs to fish and the induced oxidative stress triggered changes in lipid peroxidation, DNA damage and ubiquitination and furthermore stimulated signal transduction pathways leading to autophagy and apoptosis. The smaller PE-MPs were more potent in inducing alterations to all the latter parameters measured than the larger ones. Tissue response in both fish seems to depend on the parameter measured and does not seem to follow a specific pattern. Our results showed that there is no clear sensitivity of one fish species versus the other, against both sizes of PE-MPs they were exposed. In perch the metabolic changes in gills were distinct to the ones observed in liver, following a size dependent pattern, indicating that stress conditions are generated through different mechanisms. All the parameters employed can be suggested further as biomarkers in biomonitoring studies against PE-MPs.

Chronic toxicity effects of sediment-associated polystyrene nanoplastics alone and in combination with cadmium on a keystone benthic species Bellamya aeruginosa

Nanoplastics (NPs) are emerging pollutants that may adversely affect aquatic fauna. However, the adverse effects of NPs and heavy metals, both alone and combined on freshwater benthic fauna remain largely unclear. Here, we performed a 28-day sediment toxicity test with Bellamya aeruginosa to examine the effects of exposure to polystyrene nanoplastics (PSNPs) and co-exposure to PSNPs and Cd. Cd bioavailability, the bioaccumulation of PSNPs and Cd, and changes in multiple biomarkers were determined. The results revealed that PSNPs significantly increased Cd bioavailability and thereby facilitated Cd bioaccumulation; however, PSNPs displayed a negligible vector role in Cd uptake by B. aeruginosa. The results demonstrated that PSNPs can accumulate in B. aeruginosa and induce oxidative damage and DNA damage. Co-exposure to PSNPs and Cd significantly enhanced oxidative damage and DNA damage and reduced metallothionein levels. The integrated biomarker response index analysis showed that co-exposure to PSNPs and Cd considerably increased toxic stress in B. aeruginosa compared to single PSNPs or Cd exposure, suggesting that PSNPs may have a synergistic effect with Cd. Collectively, our findings highlight that PSNPs not only cause toxicity to B. aeruginosa but also significantly enhance the toxicity of Cd by increasing Cd bioavailability in the sediment.

Cell-Based Chemical Safety Assessment and Therapeutic Discovery Using Array-Based Sensors

Synthetic chemicals are widely used in food, agriculture, and medicine, making chemical safety assessments necessary for environmental exposure. In addition, the rapid determination of chemical drug efficacy and safety is a key step in therapeutic discoveries. Cell-based screening methods are non-invasive as compared with animal studies. Cellular phenotypic changes can also provide more sensitive indicators of chemical effects than conventional cell viability. Array-based cell sensors can be engineered to maximize sensitivity to changes in cell phenotypes, lowering the threshold for detecting cellular responses under external stimuli. Overall, array-based sensing can provide a robust strategy for both cell-based chemical risk assessments and therapeutics discovery.

Lipidomic analysis of single and combined effects of polyethylene microplastics and polychlorinated biphenyls on human hepatoma cells

Microplastics are an emerging environmental issue as a result of their ubiquity, persistence, and intrinsic toxic potential. In addition, their ability to sorb and transport a wide variety of environmental pollutants (i.e. "Trojan Horse" effect) exerts significant adverse impacts upon ecosystems. The toxicological evaluation of the single and combined effects produced by polyethylene microplastics and two polychlorinated biphenyl congeners was performed on the human hepatoma cell line HepG2 by cell viability assessment and an untargeted lipidomic study. The cell lethality evaluation evinced that MPs did not induce relevant cell lethality at any of the concentration range tested, while both PCBs presented a hormetic behavior. The lipidomic analysis suggested that both single PCB exposures induced significant lipidomic changes, especially for glycerophospholipids and glycerolipids. In contrast, for MPs single exposure, the most remarkable change was the substantial enhancement of triglyceride content. Regarding combined exposures, results showed that MPs could induce even more harmful effects than those produced intrinsically as a result of desorbing previously sorbed toxic pollutants. To the best of our knowledge, this is the first study assessing the toxicity of microplastics and their possible "Trojan Horse" effect by applying an untargeted lipidomic methodology.

Microplastics in the environment: Sampling, pretreatment, analysis and occurrence based on current and newly-exploited chromatographic approaches

The omnipresent character of microplastics (MPs) in environmental matrices, organisms and products has recently posed the need of their qualitative as well as quantitative analysis imperative, in order to provide data about their abundance and specification of polymer types in several substrates. In this framework, current and emerging approaches based on the chromatographic separation are of increased relevance in the field of MPs analysis and possess a large number of merits, since most of them are applicable in various complex matrices, sensitive and ideal for the detection of small-sized particles, whereas the common absence of any special pre-treatment step before analysis should also be highlighted. Αnalytical pyrolysis coupled with gas chromatography mass spectrometry (GC-MS) has recently gained ground as a powerful means to deliver information on MPs composition and degradation after their release into environment. Several instrumentations and trends in the area of analytical pyrolysis are thoroughly described within this review, while newly-exploited chromatographic methods in the field of MPs analysis, including Liquid Chromatography (LC) and Gel Permeation Chromatography (GPC) in this line are also investigated. The present review fills the gap of standardization concerning sampling, pre-treatment and chromatographic approaches and gathers all the available methodologies applied inside this area in accordance with the studied substrate, with the most examined environmental matrices being the solid one. After investigating the various works, some development options arise and it appears that chromatographic approaches should focus on improved extraction processes in terms of MPs isolation, since it is a crucial part in plastic items monitoring and is commonly depended on the polymer type and matrix. Special attention is given on the potential of chromatographic techniques for microplastics identification as well as quantification by confirming the current research status and knowledge gaps and highlighting some of the recent trends in this field.

Environmental pollution with antifouling paint particles: Distribution, ecotoxicology, and sustainable alternatives

Antifouling paint particles (APPs) are a type of paint particle loaded with toxic biocidal compounds. The present review focused on the current knowledge in respect of the abundance, distribution, and ecotoxicological effects of APPs in the marine environment. Also, the recent advances in nontoxic biobased antifouling paints were discussed as potential alternatives to contemporary marine coatings. The presence of APPs is mainly associated with boat maintenance in boatyards and port areas. Conventional microplastic assessments showed a significant contribution of paint particles to the morphological composition. Moreover, recent ecotoxicological studies demonstrated that environmental concentrations of APPs induce mortality (LC₅₀) in sediment dwellers and macroinvertebrates. Novel biocides from natural sources and biopolymer binders in the formulation of antifouling paints are proposed as potential alternatives to conventional antifouling paints. The toxicity of most natural biocides is negligible to nontargeted species, while biopolymers are expected to prevent the formation of APPs.

Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties-From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000-50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.