Potential role of mitochondrial damage and S9 mixture including metabolic enzymes in ZnO nanoparticles-induced oxidative stress and genotoxicity in Chinese hamster lung (CHL/IU) cells

Genotoxicity of nanoparticles evaluated using the in vitro micronucleus assay, a review of recent data§

The in vitro micronucleus assay is a well-known and established component of the standard genotoxicity test battery. The growing use of nanomaterials around the world along with human exposure to them has increased the need for risk assessment with regard to safety, including potential genotoxicity. The in vitro micronucleus assay is one of the most used tests for evaluating the genotoxicity of nanomaterials. This review compiles studies since 2017 that performed assessments of micronucleus formation in vitro after cellular exposure to different nanomaterials. Genotoxicity of a broad range of nanomaterials including silver, cerium, zinc, gold, nickel, cadmium, titanium, carbon, and aluminum in different cell types were reviewed. While clear trends could be seen for some nanoparticle types like silver and cerium nanoparticles, others like gold nanoparticles showed mixed results. This review highlights the usefulness and effectiveness of the micronucleus assay for studying the genotoxicity of nanomaterials, in part, and is also careful to note that standard guidelines should be followed when conducting this assay in order to generate reliable and quality-driven data.

Toxicologic Concerns with Current Medical Nanoparticles

Nanotechnology is one of the scientific advances in technology. Nanoparticles (NPs) are small materials ranging from 1 to 100 nm. When the shape of the supplied nanoparticles changes, the physiological response of the cells can be very different. Several characteristics of NPs such as the composition, surface chemistry, surface charge, and shape are also important parameters affecting the toxicity of nanomaterials. This review covered specific topics that address the effects of NPs on nanomedicine. Furthermore, mechanisms of different types of nanomaterial-induced cytotoxicities were described. The distributions of different NPs in organs and their adverse effects were also emphasized. This review provides insight into the scientific community interested in nano(bio)technology, nanomedicine, and nanotoxicology. The content may also be of interest to a broad range of scientists.

Cytotoxic and genotoxic effects of e-liquids and their potential associations with nicotine, menthol and phthalate esters

In this study, we determined DNA damage and chromosome breakage (indicators of genotoxicity) and cell viability (an indicator of cytotoxicity) in human lymphoblastoid TK6 and Chinese hamster ovary (CHO) cells treated with 33 e-liquids using in vitro single cell gel (comet), micronucleus (MN), and trypan blue assays, respectively. We also measured the contents of nicotine, five phthalate esters, and DL-menthol in the e-liquids to examine their effects on DNA damage, chromosome breakage, and cell viability. Our chemical analyses showed that: (1) six e-liquids had nicotine ≥2-fold higher than the manufacture's label claim (2-3.5 mg); (2) both dimethyl- and dibutyl-phthalate levels were >0.1 μg/g, i.e., their threshold limits as additives in cosmetics; and (3) the DL-menthol contents ranged from 0.0003 to 85757.2 μg/g, with those of two e-liquids being >1 mg/g, the threshold limit for trigging sensory irritation. Though all the e-liquids induced DNA damage in TK6 cells, 20 resulted in cell viabilities ≤75%, indicating cytotoxicity, yet the inverse relationship between cell viability and DNA damage (r = -0.628, p = 0.003) might reflect their role as pro-apoptotic and DNA damage inducers. Fifteen e-liquids induced MN% in TK6 cells ≥3-fold that of untreated cells. Some of the increase in %MN might be false due to high cytotoxicity, yet six brands showed acceptable cell viabilities (59-71%), indicating chromosome damage. DNA damage and %MN increased when the TK6 cells were exposed to metabolic activation. The CHO cells were less sensitive to the genotoxic effects of the e-liquids than the TK6 cells. DL-menthol was found to be associated with decreased cell viability and increased DNA damage, even at low levels. We cannot dismiss the presence of other ingredients in e-liquids with cytotoxic/genotoxic properties since out of the 63 different flavors, 47 induced DNA damage (≥3-folds), and 26 reduced cell viability (≤75%) in TK6 cells.

Potential risks and benefits of zinc oxide nanoparticles: a systematic review

Zinc oxide nanoparticles are well-known metal oxide nanoparticles having numbers of applications in the field of cosmetology, medicine, and chemistry. However, the number of reports has indicated its toxicity also such as hepatotoxicity, pulmonary toxicity, neurotoxicity, and immunotoxicity. Thus, in this article, we have analyzed the potential risks and benefits of zinc oxide nanoparticles. The data related to risks and benefits of zinc oxide nanoparticles have been extracted from PubMed (from January 2007 to August 2019). A total of 3,892 studies have been published during this period regarding zinc oxide nanoparticles. On the basis of inclusion and exclusion criteria, 277 studies have been included for the analysis of risks and benefits. Emerging reports have indicated both risks and benefits of zinc oxide nanoparticles in concentration- and time-dependent manner under in vitro and in vivo conditions through different mechanism of action. In conclusion, zinc oxide nanoparticles could play a beneficial role in the treatment of various diseases but safety of these particles at particular effective concentration should be thoroughly evaluated.