Effects of titanium dioxide nanoparticles isolated from confectionery products on the metabolic stress pathway in human lung fibroblast cells

Response to shock load of titanium dioxide nanoparticles on aerobic granular sludge and algal-bacterial granular sludge processes

Titanium dioxide nanoparticles (TiO2 NPs) are extensively used in various fields and can consequently be detected in wastewater, making it necessary to study their potential impacts on biological wastewater treatment processes. In this study, the shock-load impacts of TiO2 NPs were investigated at concentrations ranging between 1 and 200 mg L-1 on nutrient removal, extracellular polymeric substances (EPSs), microbial activity in aerobic granular sludge (AGS), and algal-bacterial granular sludge (AB-AGS) bioreactors. The results indicated that low concentration (≤10 mg L-1) TiO2 NPs had no effect on microbial activity or the removal of chemical oxygen demand (COD), nitrogen, and phosphorus, due to the increased production of extracellular polymeric substances (EPSs) in the sludge. In contrast, the performance of both AGS and AB-AGS bioreactors gradually deteriorated as the concentration of TiO2 NPs in the influent increased to 50, 100, and 200 mg L-1. Specifically, the ammonia‑nitrogen removal rate in AGS decreased from 99.9 % to 88.6 %, while in AB-AGS it dropped to 91.3 % at 200 mg L-1 TiO2 NPs. Furthermore, the nitrate‑nitrogen levels remained stable in AB-AGS, while NO3-N was detected in the effluent of AGS at 100 and 200 mg L-1. Microbial activities change similarly as smaller decrease in the specific ammonia uptake rate (SAUR) and specific nitrate uptake rate (SNUR) was found in AB-AGS compared to those in AGS. Overall, the algal-bacterial sludge exhibited higher resilience against TiO2 NPs, which was attributed to a) higher EPS volume, b) smaller decrease in LB-EPS, and c) the favorable protein to polysaccharide (PN/PS) ratio. This in turn, along with the symbiotic relationship between the algae and bacteria, mitigates the toxic effects of nanoparticles.

Co-exposure to commercial food product ingredient E341 and E551 triggers cytotoxicity in human mesenchymal stem cells

Several nano-toxicological studies have assessed the prospective health risks of engineered nanostructures. Still, nanoscale ingredients from food products are not explored well, and only a few have attended to the possible effects of food additive-based nanoparticles in food. The physicochemical properties of food additives and their fate on human health are still unknown. To fill this knowledge gap, we examined the physicochemical characteristics of food product isolate E341/E551. Additionally, we assessed the consequence of these nanoscale E341 and E551 as co-exposure on human mesenchymal stem cells (hMSCs). The transmission electron microscope (TEM) images revealed that food product isolate (E341/E551) consists of nanoscale particles. The E551 and E341 have 20-50 nm and 70-200 nm diameters, respectively. Co-exposure of food additives SiO2 (E551) and Tricalcium phosphate (E341) effect on the cell viability, morphology, mitochondrial membrane potential, and reactive oxygen species (ROS) level of hMSCs were studied. The cell viability reduction, mitochondrial membrane potential loss, and ROS generation in E341/E551 co-exposed cells were observed. Our study suggests that E341/E551 co-exposure elevated the ROS level and mitochondrial membrane potential depletion at a high dose. The oxidative stress-related genes MDM3, TNFSF10, and POR have exhibited significant upregulation in the E341/E551 treatment group. These results conclude that long-term over-exposure to E341/E551 may be triggers health risks in a human. Further in vivo studies are required for food industry implications due to nanoscale ingredients in E341 and E551.

Subchronic Oral Toxicity Study of Food-Related Titanium Dioxide Nanoparticles in Rats Involved in Ti Biodistribution and Gut Microbiota

The widespread use of titanium dioxide nanoparticles (TiO₂ NPs) in the food industry has brought about human safety risks related to nanotoxicity. In this study, food-related TiO₂ NPs (anatase, 40 nm) were given to rats by oral gavage for 90 days at doses of 10, 100, and 1000 mg/kg bw. An additional two satellite groups underwent the same protocol for 45 days and for 90 days followed by a 28 day recovery. TiO₂ NPs tended to agglomerate together in H₂O, AGJ, and AIJ. No systemic toxicity was observed after 90 day agglomerated TiO₂ NP exposure with no Ti distribution in major tissues/organs. Furthermore, TiO₂ NP consumption for 90 days had no impact on microbiota diversity; the community structure of the gut microbiota is shifted to some extent at the genus level. Collectively, the NOAEL of agglomerated TiO₂ NPs for 90 days of oral administration was 1000 mg/kg bw, the highest dose tested in male and female rats.

Effect of Titanium Dioxide Nanoparticles on Mammalian Cell Cycle In Vitro: A Systematic Review and Meta-Analysis

Although most studies that explore the cytotoxicity of titanium dioxide nanoparticles (nano-TiO₂) have focused on cell viability and oxidative stress, the cell cycle, a basic process of cell life, can also be affected. However, the results on the effects of nano-TiO₂ on mammalian cell cycle are still inconsistent. A systematic review and meta-analysis were therefore performed in this research based on the effects of nano-TiO₂ on the mammalian cell cycle in vitro to explore whether nano-TiO₂ can induce cell cycle arrest. Meanwhile, the impact of physicochemical properties of nano-TiO₂ on the cell cycle in vitro was investigated, and the response of normal cells and cancer cells was compared. A total of 33 articles met the eligibility criteria after screening. We used Review Manager 5.4 and Stata 15.1 for analysis. The results showed an increased percentage of cells in the sub-G1 phase and an upregulation of the p53 gene after being exposed to nano-TiO₂. Nevertheless, nano-TiO₂ had no effect on cell percentage in other phases of the cell cycle. Furthermore, subgroup analysis revealed that the cell percentage in both the sub-G1 phase of normal cells and S phase of cancer cells were significantly increased under anatase-form nano-TiO₂ treatment. Moreover, nano-TiO₂ with a particle size <25 nm or exposure duration of nano-TiO₂ more than 24 h induced an increased percentage of normal cells in the sub-G1 phase. In addition, the cell cycle of cancer cells was arrested in the S phase no matter if the exposure duration of nano-TiO₂ was more than 24 h or the exposure concentration was over 50 μg/mL. In conclusion, this study demonstrated that nano-TiO₂ disrupted the cell cycle in vitro. The cell cycle arrest induced by nano-TiO₂ varies with cell status and physicochemical properties of nano-TiO₂.

Physicochemical Characterization of the Pristine E171 Food Additive by Standardized and Validated Methods

E171 (titanium dioxide) is a food additive that has been authorized for use as a food colorant in the European Union. The application of E171 in food has become an issue of debate, since there are indications that it may alter the intestinal barrier. This work applied standardized and validated methodologies to characterize representative samples of 15 pristine E171 materials based on transmission electron microscopy (TEM) and single-particle inductively coupled plasma mass spectrometry (spICP-MS). The evaluation of selected sample preparation protocols allowed identifying and optimizing the critical factors that determine the measurement of the particle size distribution by TEM. By combining optimized sample preparation with method validation, a significant variation in the particle size and shape distributions, the crystallographic structure (rutile versus anatase), and the physicochemical form (pearlescent pigments versus anatase and rutile E171) was demonstrated among the representative samples. These results are important for risk assessment of the E171 food additive and can contribute to the implementation of the European Food Safety Authority (EFSA) guidance on risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain.

Toxicity mechanisms of selected engineered nanoparticles on human neural cells in vitro

Environmental exposure to nanoparticles (NPs) has significantly increased in the last decades, mostly due to increased environmental pollution and frequent use of NP containing consumer products. Such NPs may enter our body and cause various health-related problems. The brain is a particularly problematic accumulation site due to its physiological and anatomical restrictions. Several mechanisms of NP neurotoxicity have already been identified, however not enough is known especially regarding toxicity of engineered/industrial NPs. The focus of this in vitro study was on analysis of neurotoxicity of different engineered NPs, with which we come into contact in our daily lives; SiO₂ NPs, food grade (FG) TiO₂ NPs, TiO₂ P25 and silver NPs as examples of industrial NPs, and polyacrylic acid (PAA) coated cobalt ferrite NPs as an example of biomedical NPs. All short term exposure experiments (24-72 h) were performed on SH-SY5Y human neuroblastoma cell line in vitro using higher (25-50 μg/ml) as well as lower (2-10 μg/ml), concentrations that are more relevant for in vivo NPs exposure. We show that NPs can cause neurotoxicity through different mechanisms, such as membrane damage, cell cycle interference, ROS formation and accumulation of autophagosomes, depending on their physico-chemical properties and stability in physiological media. Low, in vivo achievable concentrations of NPs induced only minor or no changes in vitro, however prolonged exposure and accumulation in vivo could negatively affect the cells. This was also shown in case of autophagy dysfunction for TiO₂ P25 NPs and decrease of cell viability for TiO₂ FG NPs, which were only evident after 72 h of incubation.

Oleic acid-loaded nanostructured lipid carrier inhibit neutrophil activities in the presence of albumin and alleviates skin inflammation

Aim

This paper reports on the incorporation of oleic acid (OA) within nanostructured lipid carriers (OA-NLC) to improve the anti-inflammatory effects in the presence of albumin.

Materials and methods

NLCs produced via hot high-shear homogenization/ultrasonication were characterized in terms of particle size, zeta potential, and toxicity. We examined the effects of OA-NLC on neutrophil activities. Dermatologic therapeutic potential was also elucidated by using a murine model of leukotriene B4-induced skin inflammation.

Results

In the presence of albumin, OA-NLC but not free OA inhibited superoxide generation and elastase release. Topical administration of OA-NLC alleviated neutrophil infiltration and severity of skin inflammation.

Conclusion

OA incorporated within NLC can overcome the interference of albumin, which would undermine the anti-inflammatory effects of OA. OA-NLC has potential therapeutic effects in topical ointments.

Quantitative Proteomics Study Reveals Changes in the Molecular Landscape of Human Embryonic Stem Cells with Impaired Stem Cell Differentiation upon Exposure to Titanium Dioxide Nanoparticles

The increasing number of nanoparticles (NPs) being used in various industries has led to growing concerns of potential hazards that NP exposure can incur on human health. However, its global effects on humans and the underlying mechanisms are not systemically studied. Human embryonic stem cells (hESCs), with the ability to differentiate to any cell types, provide a unique system to assess cellular, developmental, and functional toxicity in vitro within a single system highly relevant to human physiology. Here, the quantitative proteomics approach is adopted to evaluate the molecular consequences of titanium dioxide NPs (TiO₂ NPs) exposure in hESCs. The study identifies ≈328 unique proteins significantly affected by TiO₂ NPs exposure. Proteomics analysis highlights that TiO₂ NPs can induce DNA damage, elevated oxidative stress, apoptotic responses, and cellular differentiation. Furthermore, in vivo analysis demonstrates remarkable reduction in the ability of hESCs in teratoma formation after TiO₂ NPs exposure, suggesting impaired pluripotency. Subsequently, it is found that TiO₂ NPs can disrupt hESC mesoderm differentiation into cardiomyocytes. The study unveils comprehensive changes in the molecular landscape of hESCs by TiO₂ NPs and identifies the impact which TiO₂ NPs can have on the pluripotency and differentiation properties of human stem cells.

Long-term impacts of titanium dioxide nanoparticles (TiO2 NPs) on performance and microbial community of activated sludge

The long-term impacts of titanium dioxide nanoparticles (TiO₂ NPs) on the performance and microbial community of activated sludge were evaluated in a sequencing batch reactor (SBR). TiO₂ NPs impacted the COD and phosphorus removals of activated sludge, whereas the NH₄⁺-N removal efficiency had no distinct change at 0-60mg/L TiO₂ NPs. The presence of TiO₂ NPs obviously inhibited the organic matter and nitrogen removal rates of activated sludge. The phosphorus removal rate gradually reduced at 0-5mg/L TiO₂ NPs and then increased at 10-60mg/L TiO₂ NPs. The removal rates of organic matter, nitrogen and phosphorus had the similar varying trends to the corresponding microbial enzymatic activities. High TiO₂ NPs concentration promoted more reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release of activated sludge. The microbial richness and diversity of activated sludge were obviously affected at the phyla, class and genus levels.

Cadmium triggers mitochondrial oxidative stress in human peripheral blood lymphocytes and monocytes: Analysis using in vitro and system toxicology approaches

Cadmium (Cd) is a well-known heavy metal that causes environmental pollution and human health problems. Several studies attempted to assess Cd toxicity in vitro and in vivo. However, the systemic profile of cadmium toxicity has not been studied well. In the present study, we assessed the toxicity of Cd on human peripheral blood lymphocytes and monocytes and gene expression, using a system toxicological approach. Cd effect on cell viability and morphology were analyzed by MTT assay and AO/EB staining respectively. Mitochondrial membrane potential depletion and reactive oxygen singlet generation were assessed by flow cytometry. Effects of Cd treatment on gene expression were also studied. Significant reduction in cell viability and disintegration of nuclear morphology were observed in Cd-treated cells. Cd exposure enhanced the loss of mitochondrial membrane potential through oxidative stress. Dose-dependent upregulation of GSTM3 and downregulation of GSR gene expression were observed. TNF gene expression decreased as the level of Cd exposure increased. We analyzed the toxicological effects of Cd on more than 45 proteins for biological target identification. These system toxicological studies suggested that Cd induced toxicity through various biological processes such as oxidative stress, oxidation-reduction, and ROS and hydrogen peroxide generation. Additionally, Cd affects the cellular component network and modulates the expression level of oxidative stress-related genes.

Advances in Nanotechnology as They Pertain to Food and Agriculture: Benefits and Risks

Nanotechnology is an emerging and rapidly developing toolbox that has novel and unique applications to food science and agriculture. Fast and impressive developments in nanotechnology for food and agriculture have led to new experimental prototype technologies and products. Developing various types of nanodelivery systems, detection tools, nanoscale modifications of bulk or surface properties, fabrication of wide-range bionanosensors, and biodegradable nanoplatforms can potentially improve consumer health and safety, product shelf life and stability, bioavailability, environmental sustainability, efficiency of processing and packaging, and real-time monitoring. Some recently developed nanotechnology techniques and potential product applications of nanotechnology are summarized in this review. Exposure to nanomaterials may be harmful to the consumer and the environment and might increase the potential of risk. For this reason, evaluation of the potential risks resulting from the interaction of nanomaterials with biological systems, humans, and the environment is also reviewed.

Inhaled Pollutants: The Molecular Scene behind Respiratory and Systemic Diseases Associated with Ultrafine Particulate Matter

Air pollution of anthropogenic origin is largely from the combustion of biomass (e.g., wood), fossil fuels (e.g., cars and trucks), incinerators, landfills, agricultural activities and tobacco smoke. Air pollution is a complex mixture that varies in space and time, and contains hundreds of compounds including volatile organic compounds (e.g., benzene), metals, sulphur and nitrogen oxides, ozone and particulate matter (PM). PM_0.1 (ultrafine particles (UFP)), those particles with a diameter less than 100 nm (includes nanoparticles (NP)) are considered especially dangerous to human health and may contribute significantly to the development of numerous respiratory and cardiovascular diseases such as chronic obstructive pulmonary disease (COPD) and atherosclerosis. Some of the pathogenic mechanisms through which PM_0.1 may contribute to chronic disease is their ability to induce inflammation, oxidative stress and cell death by molecular mechanisms that include transcription factors such as nuclear factor κB (NF-κB) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Epigenetic mechanisms including non-coding RNA (ncRNA) may also contribute towards the development of chronic disease associated with exposure to PM_0.1. This paper highlights emerging molecular concepts associated with inhalational exposure to PM_0.1 and their ability to contribute to chronic respiratory and systemic disease.

Genome-wide transcriptional analysis of silica nanoparticle-induced toxicity in zebrafish embryos

Although silica nanoparticles (SiNPs) have a promising application in biomedical fields, there is still a lack of comprehensive understanding of genome-wide transcriptional analysis. This study aims to clarify the toxic effect and molecular mechanisms of SiNPs in zebrafish embryos based on microarray analysis and bioinformatics analysis. Microarray data analysis demonstrated that SiNP-induced toxicity in zebrafish embryos affected expression of 2515 genes, including 1107 genes that were up-regulated and 1408 genes that were down-regulated. These differentially expressed genes were subjected to bioinformatics analysis for exploring the biological processes triggered by SiNPs in zebrafish embryos. Gene ontology analysis showed that SiNPs caused significant changes in gene expression patterns related to many important functions, including response to stimuli, immune response, cellular processes, and embryonic development. In addition, pathway analysis and Signal-net analysis indicated that the gap junction, vascular smooth muscle contraction, and metabolic pathways, apoptosis, the MAPK signaling pathway, the calcium signaling pathway and the JAK-STAT signaling pathway were the most prominent significant pathways in SiNP-induced toxicity in zebrafish embryos. In addition, the results from qRT-PCR and western blot analysis showed that the IL-6 dependent JAK1/STAT3 signaling pathway was activated by SiNPs in zebrafish embryos. In summary, our data will provide compelling clues for further exploration of SiNP-induced toxicity in zebrafish embryos.

Biomarkers of susceptibility: State of the art and implications for occupational exposure to engineered nanomaterials

Rapid advances and applications in nanotechnology are expected to result in increasing occupational exposure to nano-sized materials whose health impacts are still not completely understood. Scientific efforts are required to identify hazards from nanomaterials and define risks and precautionary management strategies for exposed workers. In this scenario, the definition of susceptible populations, which may be at increased risk of adverse effects may be important for risk assessment and management. The aim of this review is to critically examine available literature to provide a comprehensive overview on susceptibility aspects potentially affecting heterogeneous responses to nanomaterials workplace exposure. Genetic, genotoxic and epigenetic alterations induced by nanomaterials in experimental studies were assessed with respect to their possible function as determinants of susceptibility. Additionally, the role of host factors, i.e. age, gender, and pathological conditions, potentially affecting nanomaterial toxicokinetic and health impacts, were also analysed. Overall, this review provides useful information to obtain insights into the nanomaterial mode of action in order to identify potentially sensitive, specific susceptibility biomarkers to be validated in occupational settings and addressed in risk assessment processes. The findings of this review are also important to guide future research into a deeper characterization of nanomaterial susceptibility in order to define adequate risk communication strategies. Ultimately, identification and use of susceptibility factors in workplace settings has both scientific and ethical issues that need addressing.