The likelihood of intentional and unintentional engineered nanoparticle (ENP) exposure has dramatically increased due to the use of nanoenabled products. Indeed, ENPs have been incorporated in many useful products and have enhanced our way of life. However, there are many unanswered questions about the consequences of nanoparticle exposures, in particular, with regard to their potential to damage the genome and thus potentially promote cancer. In this study, we present a high-throughput screening assay based upon the recently developed CometChip technology, which enables evaluation of single-stranded DNA breaks, abasic sites, and alkali-sensitive sites in cells exposed to ENPs. The strategic microfabricated, 96-well design and automated processing improves efficiency, reduces processing time, and suppresses user bias in comparison to the standard comet assay. We evaluated the versatility of this assay by screening five industrially relevant ENP exposures (SiO2, ZnO, Fe2O3, Ag, and CeO2) on both suspension human lymphoblastoid (TK6) and adherent Chinese hamster ovary (H9T3) cell lines. MTT and CyQuant NF assays were employed to assess cellular viability and proliferation after ENP exposure. Exposure to ENPs at a dose range of 5, 10, and 20 μg/mL induced dose-dependent increases in DNA damage and cytotoxicity. Genotoxicity profiles of ZnO > Ag > Fe2O3 > CeO2 > SiO2 in TK6 cells at 4 h and Ag > Fe2O3 > ZnO > CeO2 > SiO2 in H9T3 cells at 24 h were observed. The presented CometChip platform enabled efficient and reliable measurement of ENP-mediated DNA damage, therefore demonstrating the efficacy of this powerful tool in nanogenotoxicity studies.
Zinc oxide (ZnO) nanoparticles absorb UV light efficiently while remaining transparent in the visible light spectrum rendering them attractive in cosmetics and polymer films. Their broad use, however, raises concerns regarding potential environmental health risks and it has been shown that ZnO nanoparticles can induce significant DNA damage and cytotoxicity. Even though research on ZnO nanoparticle synthesis has made great progress, efforts on developing safer ZnO nanoparticles that maintain their inherent optoelectronic properties while exhibiting minimal toxicity are limited. Here, a safer-by-design concept was pursued by hermetically encapsulating ZnO nanorods in a biologically inert, nanothin amorphous SiO2 coating during their gas-phase synthesis. It is demonstrated that the SiO2 nanothin layer hermetically encapsulates the core ZnO nanorods without altering their optoelectronic properties. Furthermore, the effect of SiO2 on the toxicological profile of the core ZnO nanorods was assessed using the Nano-Cometchip assay by monitoring DNA damage at a cellular level using human lymphoblastoid cells (TK6). Results indicate significantly lower DNA damage (>3 times) for the SiO2-coated ZnO nanorods compared to uncoated ones. Such an industry-relevant, scalable, safer-by-design formulation of nanostructured materials can liberate their employment in nano-enabled products and minimize risks to the environment and human health.
Airborne pathogens are associated with the spread of infectious diseases and increased morbidity and mortality. Herein we present an emerging chemical free, nanotechnology-based method for airborne pathogen inactivation. This technique is based on transforming atmospheric water vapor into Engineered Water Nano-Structures (EWNS) via electrospray. The generated EWNS possess a unique set of physical, chemical, morphological and biological properties. Their average size is 25 nm and they contain reactive oxygen species (ROS) such as hydroxyl and superoxide radicals. In addition, EWNS are highly electrically charged (10 electrons per particle on average). A link between their electric charge and the reduction of their evaporation rate was illustrated resulting in an extended lifetime (over an hour) at room conditions. Furthermore, it was clearly demonstrated that the EWNS have the ability to interact with and inactivate airborne bacteria. Finally, inhaled EWNS were found to have minimal toxicological effects, as illustrated in an acute in-vivo inhalation study using a mouse model. In conclusion, this novel, chemical free, nanotechnology-based method has the potential to be used in the battle against airborne infectious diseases.
Context Printers and photocopiers release respirable particles into the air. Engineered nanomaterials (ENMs) have been recently incorporated into toner formulations but their potential toxicological effects have not been well studied. Objective To evaluate the biologic responses to copier-emitted particles in the lungs using a mouse model. Methods Particles from a university copy center were sampled and fractionated into three distinct sizes, two of which (PM0.1 and PM0.1–2.5) were evaluated in this study. The particles were extracted and dispersed in deionized water and RPMI/10% FBS. Hydrodynamic diameter and zeta potential were evaluated by dynamic light scattering. The toxicologic potential of these particles was studied using 8-week-old male Balb/c mice. Mice were intratracheally instilled with 0.2, 0.6, 2.0 mg/kg bw of the PM0.1 and PM0.1–2.5 size fractions. Fe2O3 and welding fumes were used as comparative materials, while RPMI/10% FBS was used as the vehicle control. Bronchoalveolar lavage (BAL) was performed 24 hours post-instillation. The BAL fluid was analyzed for total and differential cell counts, and biochemical markers of injury and inflammation. Results Particle size- and dose-dependent pulmonary effects were found. Specifically, mice instilled with PM0.1 (2.0 mg/kg bw) had significant increases in neutrophil number, lactate dehydrogenase and albumin compared to vehicle control. Likewise, pro-inflammatory cytokines were elevated in mice exposed to PM0.1 (2.0 mg/kg bw) compared to other groups. Conclusion Our results indicate that exposure to copier-emitted nanoparticles may induce lung injury and inflammation. Further exposure assessment and toxicological investigations are necessary to address this emerging environmental health pollutant.
Nano-enabled products (NEPs) represent a growing economic global market that integrates nanotechnology into our everyday lives. Increased consumer use and disposal of NEPs at their end of life has led to increased environmental, health and safety (EHS) concerns, due to the potential environmental release of constituent engineered nanomaterials (ENMs) used in the production of NEPs. Although, there is an urgent need to assess particulate matter (PM) release scenarios and potential EHS implications, no current standardized methodologies exist across the exposure-toxicological characterization continuum. Here, an integrated methodology is presented, that can be used to sample, extract, disperse and estimate relevant dose of life cycle-released PM (LCPM), for in vitro and in vivo toxicological studies. The proposed methodology was utilized to evaluate two "real world" LCPM systems simulating consumer use and disposal of NEPs. This multi-step integrated methodology consists of: (1) real-time monitoring and sampling of size fractionated LCPM; (2) efficient extraction of LCPM collected on substrates using aqueous or ethanol extraction protocols to ensure minimal physicochemical alterations; (3) optimized LCPM dispersion preparation and characterization; (4) use of dosimetric techniques for in vitro and in vivo toxicological studies. This comprehensive framework provides a standardized protocol to assess the release and toxicological implications of ENMs released across the life cycle of NEPs and will help in addressing important knowledge gaps in the field of nanotoxicology.
In the safety and efficacy assessment of novel nanomaterials, the role of nanoparticle (NP) kinetics in in vitro studies is often ignored although it has significant implications in dosimetry, hazard ranking and nanomedicine efficacy. Here, we demonstrate that certain nanoparticles are buoyant due to low effective densities of their formed agglomerates in culture media, which alters particle transport and deposition, dose-response relationships, and underestimates toxicity and bioactivity. To investigate this phenomenon, we determined the size distribution, effective density, and assessed fate and transport for a test buoyant NP (polypropylene, PP). To enable accurate dose-response assessment, we developed an inverted 96-well cell culture platform in which adherent cells were incubated above the buoyant particle suspension. The effect of buoyancy was assessed by comparing dose-toxicity responses in human macrophages after 24 h incubation in conventional and inverted culture systems. In the conventional culture system, no adverse effects were observed at any NP concentration tested (up to 250 μg ml−1), whereas dose-dependent decreases in viability and increases in reactive oxygen species were observed in the inverted system. This work sheds light on an unknown issue that plays a significant role in vitro hazard screening and proposes a standardized methodology for buoyant NP assessments.
To assess chemical toxicity, current high throughput screening (HTS) assays rely primarily on in vitro measurements using cultured cells. Responses frequently differ from in vivo results due to the lack of physical and humoral interactions provided by the extracellular matrix, cell-cell interactions, and other molecular components of the native organ. To more accurately reproduce organ complexity in HTS, we developed an organotypic assay using the cryopreserved precision cut lung slice (PCLS) from rats and mice. Compared to the never-frozen PCLS, their frozen-thawed counterpart slices showed viability or metabolic activity that is decreased to an extent comparable to that observed in other cryopreserved cells and tissues, but shows no differences in further changes in cell viability, mitochondrial integrity, and glutathione activity in response to the model toxin zinc chloride (ZnCl2). Notably, these measurements were successfully miniaturized so as to establish HTS capacity in a 96-well plate format. Finally, PCLS responses correlated with common markers of lung injury measured in lavage fluid from rats intratracheally instilled with ZnCl2. In summary, we establish that the cryopreserved PCLS is a feasible approach for HTS investigations in predictive toxicology.
Aim As engineered nanoparticles (ENPs) increasingly enter consumer products, humans become increasingly exposed. The first line of defense against ENPs is the epithelium, the integrity of which can be compromised by wounds induced by trauma, infection, or surgery, but the implications of ENPs on wound healing are poorly understood. Materials & methods Herein, we developed an in vitro assay to assess the impact of ENPs on the wound healing of cells from human cornea. Results & discussion We show that industrially relevant ENPs impeded wound healing and cellular migration in a manner dependent on the composition, dose and size of the ENPs as well as cell type. CuO and ZnO ENPs impeded both viability and wound healing for both fibroblasts and epithelial cells. Carboxylated polystyrene ENPs retarded wound healing of corneal fibroblasts without affecting viability. Conclusion Our results highlight the impact of ENPs on cellular wound healing and provide useful tools for studying the physiological impact of ENPs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.