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Microplastics (MPs) are ubiquitous anthropogenic contaminants, and their abundance in the entire ecosystem raises the question of how far is the impact of these MPs on the biota, humans, and the environment. Recent research has overemphasized the occurrence, characterization, and direct toxicity of MPs; however, determining and understanding their genotoxic effect is still limited. Thus, the present review addresses the genotoxic potential of these emerging contaminants in aquatic organisms and in human peripheral lymphocytes and identified the research gaps in this area. Several genotoxic endpoints were implicated, including the frequency of micronuclei (MN), nucleoplasmic bridge (NPB), nuclear buds (NBUD), DNA strand breaks, and the percentage of DNA in the tail (%Tail DNA). In addition, the mechanism of MPs-induced genotoxicity seems to be closely associated with reactive oxygen species (ROS) production, inflammatory responses, and DNA repair interference. However, the gathered information urges the need for more studies that present environmentally relevant conditions. Taken into consideration, the lifestyle changes within the COVID-19 pandemic, we discussed the impact of the pandemic on enhancing the genotoxic potential of MPs whether through increasing human exposure to MPs via inappropriate disposal and overconsumption of plastic-based products or by disrupting the defense system owing to unhealthy food and sleep deprivation as well as stress. Overall, this review provided a reference for the genotoxic effect of MPs, their mechanism of action, as well as the contribution of COVID-19 to increase the genotoxic risk of MPs. [Display omitted] • The genotoxic effects of MPs are determined in somatic cells of aquatic organisms and human peripheral lymphocytes. • The mechanism of MPs-induced genotoxicity is associated with oxidative stress, inflammation, and DNA repair disruption. • The COVID-19 pandemic contributes to the genotoxic potential of MPs. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticles (IONPs) have useful properties, such as strong magnetism and compatibility with living organisms which is preferable for medical applications such as drug delivery and imaging. However, increasing use of these materials, especially in medicine, has raised concerns regarding potential risks to human health. In this study, IONPs were coated with silicon dioxide (SiO 2), citric acid (CA), and polyethylenimine (PEI) to enhance their dispersion and biocompatibility. Both coated and uncoated IONPs were assessed for genotoxic effects on Drosophila melanogaster. Results showed that uncoated IONPs induced genotoxic effects, including mutations and recombinations, while the coated IONPs demonstrated reduced or negligible genotoxicity. Additionally, bioinformatic analyses highlighted potential implications of induced recombination in various cancer types, underscoring the importance of understanding nanoparticle-induced genomic instability. This study highlights the importance of nanoparticle coatings in reducing potential genotoxic effects and emphasizes the necessity for comprehensive toxicity assessments in nanomaterial research. • Uncoated IONPs have both mutagenic and recombinogenic activity. • The IONPs were separately coated with three different coating materials. • SiO 2 , PEI and CA coatings reduced IONP genotoxicity. [ABSTRACT FROM AUTHOR]

Quaternary ammonium compounds (QACs) are commonly used as disinfectants for industrial, medical, and residential applications. However, adverse health outcomes have been reported. Therefore, biocompatible disinfectants must be developed to reduce these adverse effects. In this context, QACs with various alkyl chain lengths (C12–C18) were synthesized by reacting QACs with the counterion silane. The antimicrobial activities of the novel compounds against four strains of microorganisms were assessed. Several in vivo assays were conducted on Drosophila melanogaster to determine the toxicological outcomes of Si-QACs, followed by computational analyses (molecular docking, simulation, and prediction of skin sensitization). The in vivo results were combined using a cheminformatics approach to understand the descriptors responsible for the safety of Si-QAC. Si-QAC-2 was active against all tested bacteria, with minimal inhibitory concentrations ranging from 13.65 to 436.74 ppm. Drosophila exposed to Si-QAC-2 have moderate-to-low toxicological outcomes. The molecular weight, hydrophobicity/lipophilicity, and electron diffraction properties were identified as crucial descriptors for ensuring the safety of the Si-QACs. Furthermore, Si-QAC-2 exhibited good stability and notable antiviral potential with no signs of skin sensitization. Overall, Si-QAC-2 (C14) has the potential to be a novel disinfectant. [Display omitted] • New silane quaternary ammonium disinfectants were synthesized. • The antimicrobial effect depends on alkyl chain length and the presence of silane. • Mutagenicity/genotoxicity were observed on low alkyl chain compounds. • From in vivo / in silico data one compound (Si-QAC2) was selected as a promising disinfectant. • In silico data detect crucial descriptors to guarantee the safety of Si-QAC. [ABSTRACT FROM AUTHOR]

Although the use of synthetic amorphous silica (SAS) is steady increasing, scarce information exists on its potential health risk. In particular few and conflictive data exist on its genotoxicity. To fill in this gap we have used Drosophila melanogaster as in vivo model test organism to detect the genotoxic activity of different SAS with different primary sizes (6, 15, 30 and 55 nm). The wing-spot assay and the comet assay in larvae haemocytes were used, and the obtained results were compared with those obtained with the microparticulated form (silicon dioxide). All compounds were administered to third instar larvae at concentrations ranging from 0.1 to 10 mM. No significant increases in the frequencies of mutant spots were observed in the wing-spot assay with any of the tested compounds. On the other hand, significant dose-dependent increases in the levels of primary DNA damage, measured by the comet assay, were observed for all the SAS evaluated but mainly when high doses (5 and 10 mM) were used. These in vivo results contribute to increase the database dealing with the potential genotoxic risk associated to SAS nanoparticles exposure. [ABSTRACT FROM AUTHOR]