The effect of airborne Palladium nanoparticles on human lung cells, endothelium and blood - A combinatory approach using three in vitro models

Toxicity of real-world PM2.5 road tunnel emissions using a mobile Air-Liquid Interface system and submerged exposure

Traffic-related air pollution is a major public health concern, contributing to respiratory and cardiovascular diseases worldwide. The aim of this study was to investigate the feasibility of using a mobile Air-Liquid Interface (ALI) system to assess the cytotoxicity and inflammatory potential of freshly generated PM2.5 (particle matter with aerodynamic diameter <2.5 μm) in a road tunnel in Stockholm. We hypothesized that cellular effects would be detectable at lower doses compared to submerged exposures. The mean particle dose in ALI was 1.4±0.8 μg/cm2, whereas a wide range of doses was used for submerged exposures. ALI and submerged results showed that PM2.5 from the road tunnel did not affect the viability of A549 cells, whereas a significant and dose-dependent decrease in viability of dTHP-1 (in submerged exposure) was observed. Furthermore, in A549 in ALI a slight increase in inflammatory response (IL-8, IL-6, and IL-1β) was observed. In submerged exposure, the inflammatory response was clearer, particularly in the dTHP-1 cells. In conclusion, this study presents the first successfully conducted in situ ALI exposure in a road tunnel. The results demonstrate that dTHP-1 cells exhibit clear cytotoxic and inflammatory responses, while A549 show only weak effects. These findings suggest that co-cultures of A549 and dTHP-1 may be valuable in future ALI studies.

The blood response to subway-derived iron nanoparticles

In this study, we investigated the impact of iron-rich nanoparticles derived from different locations in the subway on the innate immune system in blood. Nanoparticles were generated from Third Rail, Rail, and Wheel materials and characterized using several techniques. The response in a human whole-blood model was analyzed using ELISA and capillary immunoelectrophoresis. All nanoparticles were iron oxides, but Third Rail nanoparticles also contained Silicon and were highly thrombo-inflammatory, activating Factor XI-induced coagulation and pro-inflammatory kallikrein/kinin pathways. Wheel and Rail nanoparticles were less reactive, mainly activating the kallikrein/kinin pathway, leading to milder inflammatory reactions. The strong thrombo-inflammatory properties of Third Rail nanoparticles are attributed to their high Silicon content. None of the nanoparticles significantly activated the complement system. In conclusion, we found that the elemental composition of nanoparticles is crucial in determining whether activation leads to kallikrein/kinin system activation and bradykinin release or Factor XI activation and thrombosis.

Nicotine interacts with DNA lesions induced by alpha radiation which may contribute to erroneous repair in human lung epithelial cells

PURPOSE

Epidemiological studies show that radon and cigarette smoke interact in inducing lung cancer, but the contribution of nicotine in response to alpha radiation emitted by radon is not well understood.

MATERIALS AND METHODS

Bronchial epithelial BEAS-2B cells were either pre-treated with 2 µM nicotine during 16 h, exposed to radiation, or the combination. DNA damage, cellular and chromosomal alterations, oxidative stress as well as inflammatory responses were assessed to investigate the role of nicotine in modulating responses.

RESULTS

Less γH2AX foci were detected at 1 h after alpha radiation exposure (1-2 Gy) in the combination group versus alpha radiation alone, whereas nicotine alone had no effect. Comet assay showed less DNA breaks already just after combined exposure, supported by reduced p-ATM, p-DNA-PK, p-p53 and RAD51 at 1 h, compared to alpha radiation alone. Yet the frequency of translocations was higher in the combination group at 27 h after irradiation. Although nicotine did not alter G2 arrest at 24 h, it assisted in cell cycle progression at 48 h post radiation. A slightly faster recovery was indicated in the combination group based on cell viability kinetics and viable cell counts, and significantly using colony formation assay. Pan-histone acetyl transferase inhibition using PU139 blocked the reduction in p-p53 and γH2AX activation, suggesting a role for nicotine-induced histone acetylation in enabling rapid DNA repair. Nicotine had a modest effect on reactive oxygen species induction, but tended to increase alpha particle-induced pro-inflammatory IL-6 and IL-1β (4 Gy). Interestingly, nicotine did not alter gamma radiation-induced γH2AX foci.

CONCLUSIONS

This study provides evidence that nicotine modulates alpha-radiation response by causing a faster but more error-prone repair, as well as rapid recovery, which may allow expansion of cells with genomic instabilities. These results hold implications for estimating radiation risk among nicotine users.

Toxicity of airborne nanoparticles: Facts and challenges

Air pollution is one of the most severe environmental healthhazards, and airborne nanoparticles (diameter <100 nm) are considered particularly hazardous to human health. They are produced by various sources such as internal combustion engines, wood and biomass burning, and fuel and natural gas combustion, and their origin, among other parameters, determines their intrinsic toxicity for reasons that are not yet fully understood. Many constituents of the nanoparticles are considered toxic or at least hazardous, including polycyclic aromatic hydrocarbons (PAHs) and heavy metal compounds, in addition to gaseous pollutants present in the aerosol fraction, such as NOx, SO2, and ozone. All these compounds can cause oxidative stress, mitochondrial damage, inflammation in the lungs and other tissues, and cellular organelles. Epidemiological investigations concluded that airborne pollution may affect the respiratory, cardiovascular, and nervous systems. Moreover, particulate matter has been linked to an increased risk of lung cancer, a carcinogenic effect not related to DNA damage, but to the cellular inflammatory response to the pollutants, in which the release of cytokines promotes the proliferation of pre-existing mutated cancer cells. The mechanisms behind toxicity can be investigated experimentally using cell cultures or animal models. Methods for gathering particulate matter have been explored, but standardized protocols are needed to ensure that the samples accurately represent chemical mixtures in the environment. Toxic constituents of nanoparticles can be studied in animal and cellular models, but designing realistic exposure settings is challenging. The air-liquid interface (ALI) system directly exposes cells, mimicking particle inhalation into the lungs. Continuous research and monitoring of nanoparticles and other airborne pollutants is essential for understanding their effects and developing active strategies to mitigate their risks to human and environmental health.

Examining the effectiveness of municipal street sweeping in removing road-deposited particles and metal(loid)s of respiratory health concern

Road dust is a demonstrated source of urban air pollution. Given this, the implementation of street sweeping strategies that effectively limit road dust accumulation and resuspension should be a public health priority. Research examining the effectiveness of street sweeping for road dust removal in support of good air quality has been limited to date. To address this, the study aimed to assess the use of a regenerative-air street sweeper to efficiently remove road dust particles and metal(loid)s in size fractions relevant for respiratory exposure in Toronto, Canada. As part of this, the mass amounts, particle size distribution and elemental concentrations of bulk road dust before and after sweeping at five arterial sites were characterized. Sweeping reduced the total mass amount of thoracic-sized (<10 µm) road dust particles by 76 % on average. A shift in the size distribution of remaining particles toward finer fractions was observed in post-sweeping samples, together with an enrichment in many metal(loid)s such as Co, Ti and S. Overall, the mass amounts of metal(loid)s of respiratory health concern like Cu and Zn were greatly reduced with sweeping. Traffic volume and road surface quality were predictors of dust loadings and elemental concentrations. Road surface quality was also found to impact street sweeping efficiencies, with larger mass amounts per unit area collected post-sweeping where street surfaces were distressed. This study demonstrates that street sweeping using advanced technology can be highly effective for road dust removal, highlighting its potential to support air quality improvement efforts. The importance of tailoring sweeping service levels and technologies locally as per the quality of road surface and traffic patterns is emphasized. Continued efforts to mitigate non-exhaust emissions that pose a respiratory health risk at their source is essential.

Two-photon fluorescence probe for palladium with perchlorate induced quenching mechanism and its application in smartphone-based rapid detection

We propose a new approach for detecting palladium using a two-photon fluorescent probe quenched by perchlorate. This newly developed method has the potential to overcome some of the limitations of the currently available methods for detecting palladium. This article provides a detailed introduction to the design and synthesis of fluorescent probe, as well as the fluorescence performance in aqueous solutions. The results demonstrate the probe is highly sensitive, selective, and efficient in detecting palladium. The study also includes a thorough analysis of the quenching mechanism of the probe by perchlorate, and obtained different results from previous literatures. Moreover, the probe can easily identify and differentiate between palladium being present in the valence states 0, + 2/+ 4, and accomplish detecting palladium in convoluted solutions such as wastewater, environmental water, Hela cells and zebrafish. Due to its excellent performance, using self-developed optical device, the possibility of detecting palladium in aqueous solutions based on smartphone was explored.

Screening of low-toxic zinc oxide nanomaterials and study the apoptosis mechanism of NSC-34 cells

With the increasing application of ZnO nanomaterials (ZnO-NMts) in the biomedical field, it is crucial to assess their potential risks to humans and the environment. Therefore, this study aimed to screen for ZnO-NMts with low toxicity and establish safe exposure limits, and investigate their mechanisms of action. The study synthesized 0D ZnO nanoparticles (ZnO NPs) and 3D ZnO nanoflowers (ZnO Nfs) with different morphologies using a hydrothermal approach for comparative research. The ZnO-NMts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Mouse brain neuronal cells (NSC-34) were incubated with ZnO NMts for 6, 12, and 24 h, and the cell morphology was observed using TEM. The toxic effects of ZnO Nfs on NSC-34 cells were studied using CCK-8 cell viability detection, reactive oxygen species (ROS) measurement, caspase-3 activity detection, Annexin V-FITC/PI apoptosis assay, and mitochondrial membrane potential (Δφm) measurement. The results of the research showed that ZnO-NMts caused cytoplasmic vacuolization and nuclear pyknosis. After incubating cells with 12.5 µg mL-1 ZnO-NMts for 12 h, ZnO NRfs exhibited the least toxicity and ROS levels. Additionally, there was a significant increase in caspase-3 activity, depolarization of mitochondrial membrane potential (Δφm), and the highest rate of early apoptosis.This study successfully identified ZnO NRfs with the lowest toxicity and determined the safe exposure limit to be < 12.5 µg mL-1 (12 h). These findings will contribute to the clinical use of ZnO NRfs with low toxicity and provide a foundation for further research on their potential applications in brain disease treatment.