In vitro and in vivo genotoxicity assessment of gold nanoparticles of different sizes by comet and SMART assays

Tuning Biocompatibility and Bactericidal Efficacy as a Function of Doping of Gold in ZnO Nanocrystals

Doping nanoparticles represents a strategy for modulating the energy levels and surface states of nanocrystals (NCs), thereby enhancing their efficiency and mitigating toxicity. Thus, we herein focus on the successful synthesis of pure and gold (Au)-doped zinc oxide (ZnO) nanocrystals (NCs), investigating their physical-chemical properties and evaluating their applicability and toxicity through in vitro and in vivo assessments. The optical, structural, and photocatalytic characteristics of these NCs were scrutinized by using optical absorption (OA), X-ray diffraction (XRD), and methylene blue degradation, respectively. The formation and doping of the NCs were corroborated by the XRD and OA results. While the introduction of Au as a dopant did induce changes in the phase and size of ZnO, a high concentration of Au ions in ZnO led to a reduction in their photocatalytic activity. This demonstrated a restricted antibacterial efficacy against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Remarkably, Au-doped counterparts exhibited enhanced biocompatibility in comparison to ZnO, as evidenced in both in vitro (murine macrophage cells) and in vivo (Drosophila melanogaster) studies. Furthermore, confocal microscopy images showed a high luminescence of Au-doped ZnO NCs in vivo. Thus, this study underscores the potential of Au doping of ZnO NCs as a promising technique to enhance material properties and increase biocompatibility.

L-carnitine Attenuates DNA Damage and Oxidative Stress in Diabetic Animals

Background: Diabetes is a metabolic disorder characterized by high plasma glucose levels. In this disease, increased production of reactive oxygen species (ROS) results in DNA damage and multiple complications. L-carnitine (LC) has shown a potent antioxidant activity that may reduce oxidative stress. Objectives: This study aims at assaying the effect of LC on DNA damage in streptozotocin-induced diabetic rats and evaluating the changes in antioxidant markers and liver function enzymes after the administration of LC . Methods: In the present study, for induction of diabetes, we injected a single dose of streptozotocin (65 mg/kg) by the intraperitoneal route, and diabetic rats were treated with LC 200, 300, and 400 mg/kg daily for 3 weeks. We detected the DNA damage at 7, 14, and 21 days after induction diabetes by the comet assay method. The blood glucose level, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were tested. Also, we measured the activity levels of superoxide dismutase (SOD) and intracellular glutathione (GSH). Results: The results of this study demonstrated the increasing amount of DNA damage with the amount and duration of hyperglycemia. L-carnitine treatment significantly decreased the parameters of genotoxicity such as % DNA in the tail, tail length, and tail moment over time. Moreover, the treatment of diabetic rats with LC 300 and 400 mg/kg/day after 21 days led to a remarkable decrease in blood glucose than diabetic rats. Also, we observed that LC can ameliorate enzyme liver function and reduce oxidative stress via enhancement of GSH and SOD levels. Conclusions: The results of this study indicated the protective effect of LC against DNA damage and oxidative stress in diabetic rats.

Safety Assessment of Nanomaterials in Cosmetics: Focus on Dermal and Hair Dyes Products

Nanomaterials use in cosmetics is markedly enhancing, so their exposure and toxicity are important parameters to consider for their risk assessment. This review article provides an overview of the active cosmetic ingredients used for cosmetic application, including dermal cosmetics and also hair dye cosmetics, as well as their safety assessment, enriched with a compilation of the safety assessment tests available to evaluate the different types of toxicity. In fact, despite the increase in research and the number of papers published in the field of nanotechnology, the related safety assessment is still insufficient. To elucidate the possible effects that nanosized particles can have on living systems, more studies reproducing similar conditions to what happens in vivo should be conducted, particularly considering the complex interactions of the biological systems and active cosmetic ingredients to achieve newer, safer, and more efficient nanomaterials. Toward this end, ecological issues and the toxicological pattern should also be a study target.

Publication trends of somatic mutation and recombination tests research: a bibliometric analysis (1984‒2020)

Human exposure to pollutants has been on the rise. Thus, researchers have been focused on understanding the effect of these compounds on human health, especially on the genetic information by using various tests, among them the somatic mutation and recombination tests (SMARTs). It is a sensitive and accurate method applicable to genotoxicity analysis. Here, a comprehensive bibliometric analysis of SMART assays in genotoxicity studies was performed to assess publication trends of this field. Data were extracted from the Web of Science database and analyzed by the bibliometric tools HistCite, Biblioshiny (RStudio), VOSViewer, and CiteSpace. Results have shown an increase in the last 10 years in terms of publication. A total of 392 records were published in 96 sources mainly from Brazil, Spain, and Turkey. Research collaboration networks between countries and authors were performed. Based on document co-citation, five large research clusters were identified and analyzed. The youngest research frontier emphasized on nanoparticles. With this study, how research trends evolve over years was demonstrated. Thus, international collaboration could be enhanced, and a promising field could be developed.

Genotoxicity Assessment of Metal-Based Nanocomposites Applied in Drug Delivery

Nanocomposites as drug delivery systems (e.g., metal nanoparticles) are being exploited for several applications in the biomedical field, from therapeutics to diagnostics. Green nanocomposites stand for nanoparticles of biocompatible, biodegradable and non-toxic profiles. When using metal nanoparticles for drug delivery, the question of how hazardous these "virus-sized particles" can be is posed, due to their nanometer size range with enhanced reactivity compared to their respective bulk counterparts. These structures exhibit a high risk of being internalized by cells and interacting with the genetic material, with the possibility of inducing DNA damage. The Comet Assay, or Single-Cell Gel Electrophoresis (SCGE), stands out for its capacity to detect DNA strand breaks in eukaryotic cells. It has huge potential in the genotoxicity assessment of nanoparticles and respective cells' interactions. In this review, the Comet assay is described, discussing several examples of its application in the genotoxicity evaluation of nanoparticles commonly administered in a set of routes (oral, skin, inhaled, ocular and parenteral administration). In the nanoparticles boom era, where guidelines for their evaluation are still very limited, it is urgent to ensure their safety, alongside their quality and efficacy. Comet assay or SCGE can be considered an essential tool and a reliable source to achieve a better nanotoxicology assessment of metal nanoparticles used in drug delivery.

Evaluation of the Targeting and Therapeutic Efficiency of Anti-EGFR Functionalised Nanoparticles in Head and Neck Cancer Cells for Use in NIR-II Optical Window

Gold nanoparticles have been indicated for use in a diagnostic and/or therapeutic role in several cancer types. The use of gold nanorods (AuNRs) with a surface plasmon resonance (SPR) in the second near-infrared II (NIR-II) optical window promises deeper anatomical penetration through increased maximum permissible exposure and lower optical attenuation. In this study, the targeting and therapeutic efficiency of anti-epidermal growth factor receptor (EGFR)-antibody-functionalised AuNRs with an SPR at 1064 nm was evaluated in vitro. Four cell lines, KYSE-30, CAL-27, Hep-G2 and MCF-7, which either over- or under-expressed EGFR, were used once confirmed by flow cytometry and immunofluorescence. Optical microscopy demonstrated a significant difference (p < 0.0001) between targeted AuNRs (tAuNRs) and untargeted AuNRs (uAuNRs) in all four cancer cell lines. This study demonstrated that anti-EGFR functionalisation significantly increased the association of tAuNRs with each EGFR-positive cancer cell. Considering this, the MTT assay showed that photothermal therapy (PTT) significantly increased cancer cell death (>97%) in head and neck cancer cell line CAL-27 using tAuNRs but not uAuNRs, apoptosis being the major mechanism of cell death. This successful targeting and therapeutic outcome highlight the future use of tAuNRs for molecular photoacoustic imaging or tumour treatment through plasmonic photothermal therapy.

Human Hazard Assessment Using Drosophila Wing Spot Test as an Alternative In Vivo Model for Genotoxicity Testing-A Review

Genomic instability, one of cancer's hallmarks, is induced by genotoxins from endogenous and exogenous sources, including reactive oxygen species (ROS), diet, and environmental pollutants. A sensitive in vivo genotoxicity test is required for the identification of human hazards to reduce the potential health risk. The somatic mutation and recombination test (SMART) or wing spot test is a genotoxicity assay involving Drosophila melanogaster (fruit fly) as a classical, alternative human model. This review describes the principle of the SMART assay in conjunction with its advantages and disadvantages and discusses applications of the assay covering all segments of health-related industries, including food, dietary supplements, drug industries, pesticides, and herbicides, as well as nanoparticles. Chemopreventive strategies are outlined as a global health trend for the anti-genotoxicity of interesting herbal extract compounds determined by SMART assay. The successful application of Drosophila for high-throughput screening of mutagens is also discussed as a future perspective.

Gold Nanoparticles Radio-Sensitize and Reduce Cell Survival in Lewis Lung Carcinoma

It has been suggested that particle size plays an important role in determining the genotoxicity of gold nanoparticles (GNPs). The purpose of this study was to compare the potential radio-sensitization effects of two different sized GNPs (3.9 and 37.4 nm) fabricated and examined in vitro in Lewis lung carcinoma (LLC) as a model of non-small cell lung cancer through use of comet and clonogenic assays. After treatment with 2Gy X-ray irradiation, both particle sizes demonstrated increased DNA damage when compared to treatment with particles only and radiation alone. This radio-sensitization was further translated into a reduction in cell survival demonstrated by clonogenicity. This work indicates that GNPs of both sizes induce DNA damage in LLC cells at the tested concentrations, whereas the 37.4 nm particle size treatment group demonstrated greater significance in vitro. The presented data aids in the evaluation of the radiobiological response of Lewis lung carcinoma cells treated with gold nanoparticles.

Assessment of the cytotoxic and genotoxic potential of pillar[5]arene derivatives by Allium cepa roots and Drosophila melanogaster haemocytes

In this study pillar[5]arene (P5) and a quinoline-functionalized pillar[5]arene (P5-6Q) which is used for detecting radioactive element, gas adsorption and toxic ions were synthesized. These materials were characterized by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared (FTIR), elemental analysis, melting point, Mass Spectroscopy, Scanning Electron Microscopy (SEM) and Zeta Potential. The cytotoxic and genotoxic potential of P5 and P5-6Q at distinct concentrations of 12.5, 25, 50, and 100 μg/mL were also investigated by Allium ana-telophase and comet assays on Allium cepa roots and Drosophila melanogaster haemocytes. P5 and P5-6Q showed dose dependent cytotoxic effect by decreasing mitotic index (MI) and genotoxic effect by increasing chromosomal aberrations (CAs such as disturbed anaphase-telophase, polyploidy, stickiness, chromosome laggards and bridges) and DNA damage at the exposed concentrations. These changes in P5-6Q were lower than P5. Further research is necessary to clarify the cytotoxic and genotoxic action mechanisms of P5 and P5-6Q at molecular levels.

More data on in vitro assessment of comparative and combined toxicity of metal oxide nanoparticles

Isolated and combined damaging effects of PbO and CuO nanoparticles were estimated on an established line of human fibroblasts by a decrease in: (a) the cellular dehydrogenase activity (MTT Assay), (b) the ATP content (Luminescent Cell Viability Assay), (c) the cellular proliferation, viability, spreading, and attachment to substrate evaluated integrally by continuous impedance-based measurement of the Normalized Cell Index. Using all these indices, we demonstrate an explicit dependence of cell damage on the concentrations of both metal oxide nanoparticle (MeO-NP) species. This dependence is adequately approximated with a hyperbolic function. At equal exposure levels, PbO-NP and CuO-NP demonstrate quantitatively similar cytotoxicities. The same was observed previously for some non-specific in vivo toxicity measures. The combined in vitro cytotoxicity has also been described mathematically using the Response Surface Methodology and found to be represented by various types, thus corroborating, in this respect also, the findings of a previous animal experiment with the same MeO-NPs.

An automatable platform for genotoxicity testing of nanomaterials based on the fluorometric γ-H2AX assay reveals no genotoxicity of properly surface-shielded cadmium-based quantum dots

The large number of nanomaterial-based applications emerging in the materials and life sciences and the foreseeable increasing use of these materials require methods that evaluate and characterize the toxic potential of these nanomaterials to keep safety risks to people and environment as low as possible. As nanomaterial toxicity is influenced by a variety of parameters like size, shape, chemical composition, and surface chemistry, high throughput screening (HTS) platforms are recommended for assessing cytotoxicity. Such platforms are not yet available for genotoxicity testing. Here, we present first results obtained for application-relevant nanomaterials using an automatable genotoxicity platform that relies on the quantification of the phosphorylated histone H2AX (γ-H2AX) for detecting DNA double strand breaks (DSBs) and the automated microscope system AKLIDES® for measuring integral fluorescence intensities at different excitation wavelengths. This platform is used to test the genotoxic potential of 30 nm-sized citrate-stabilized gold nanoparticles (Au-NPs) as well as micellar encapsulated iron oxide nanoparticles (FeOx-NPs) and different cadmium (Cd)-based semiconductor quantum dots (QDs), thereby also searching for positive and negative controls as reference materials. In addition, the influence of the QD shell composition on the genotoxic potential of these Cd-based QDs was studied, using CdSe cores as well as CdSe/CdS core/shell and CdSe/CdS/ZnS core/shell/shell QDs. Our results clearly revealed the genotoxicity of the Au-NPs and its absence in the FeOx-NPs. The genotoxicity of the Cd-QDs correlates with the shielding of their Cd-containing core, with the core/shell/shell architecture preventing genotoxicity risks. The fact that none of these nanomaterials showed cytotoxicity at the chosen particle concentrations in a conventional cell viability assay underlines the importance of genotoxicity studies to assess the hazardous potential of nanomaterials.

Genotoxic and mutagenic assessment of spinosad using bioassays with Tradescantia pallida and Drosophila melanogaster

Spinosad (SPN) is a naturally-occurring insecticide obtained from the fermentation process of the actinomycete Saccharopolyspora spinosa. Owing to the larvicidal action, the compound has been used in the control of Aedes aegypti. As a new insecticide commercially available in the market, few data are reported on genotoxic effects in non-target organisms. The objective of the present study was to evaluate the mutagenic effect of SPN through the Micronucleus Test in Tradescantia pallida (Trad-MCN) and using the mutation and somatic recombination test in Drosophila melanogaster (SMART). At the Trad-MCN, after acclimatization (24 h), T. pallida stems were submitted to chronic treatment with SPN at concentrations of 0.156; 0.312; 0.625; 1.25 and 2.5 g/L solution for 24 h, followed by a recovery period. In SMART, considering the third stage larvae, offspring resulting from the ST and HB crossing were placed on chronic treatment (48 h) with 0.039; 0.078 and 0.156 μg/mL of SPN solution. No mutagenic effect was observed at any of the evaluated concentrations in SMART. Additionally, SPN is more toxic after metabolism via CYP6A2 (cytochrome P450) in D. melanogaster. However, SPN at the concentrations of 0.625; 1.25 and 2.5 g/L was able to induce high frequency of micronuclei in T. pallida. Under the experimental conditions of T. pallida in the present study, SPN caused genotoxic activity.