Toxicological Consequences of Titanium Dioxide Nanoparticles (TiO(2)NPs) and Their Jeopardy to Human Population

Characterisation of titanium dioxide (nano)particles in foodstuffs and E171 additives by single particle inductively coupled plasma-tandem mass spectrometry using a highly efficient sample introduction system

This study addressed primarily the characterisation and quantification of titanium dioxide (TiO2) (nano)particles (NPs) in a large variety of commercial foodstuffs. The samples were purchased from local markets in Spain before the ban of TiO2 food additive (E171) in the EU. The analyses were carried out by single particle inductively coupled plasma-tandem mass spectrometry (spICP-MS/MS) in mass shift mode (oxidation of 48Ti to 48Ti16O (m/z = 64)) and using a highly efficient sample introduction system (APEX™ Ω). This novel analytical approach allowed accurate characterisation of a large panel of TiO2 NPs sizes ranging from ∼12 to ∼800 nm without isobaric interferences from 48Ca isotope, which is highly abundant in most of the analysed foodstuffs. TiO2 NPs were extracted from foodstuffs using sodium dodecyl sulphate (0.1%, w/v) and diluted with ultra-pure water to reach ∼ 1000 particles signals per acquisition. All the analysed samples contained TiO2 NPs with concentrations ranging from 1010 to 1014 particles kg-1, but with significant low recoveries compared to the total Ti determination. A selection of samples was also analysed using a similar spICP-MS/MS approach with a conventional sample introduction system. The comparison of results highlighted the improvement of the limit of detection in size (12 nm) by the APEX™ Ω system, providing nanoparticulate fractions ranging from ∼4% (cheddar sauce) up to ∼87% (chewing gum), which is among the highest nanoparticulate fractions reported in literature using a spICP-MS approach. In addition, two commercially available E171 additives were analysed using the previous approaches and other techniques in different European laboratories with the aim of methods inter-comparison. This study provides occurrence data related to TiO2 NPs in common commercial foodstuffs but it also demonstrates the potential of the novel analytical approach based on APEX™-ICP-MS/MS to characterise nano-size TiO2 particles in complex matrices such as foodstuffs.

Ultra-processed food consumption and risk of chronic respiratory diseases mortality among adults: evidence from a prospective cohort study

PURPOSE

The purpose of the study was to determine the relationships between ultra-processed food (UPF) consumption and risk of mortality due to chronic respiratory diseases (CRDs) overall, chronic obstructive pulmonary disease (COPD), and lung cancer.

METHODS

A total of 96,607 participants aged 55 years and over were included from the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer trial. Dietary intake was measured using food frequency questionnaire. Cox regression was fitted to estimate the risk of all-cause mortality and mortality due to CRDs overall, COPD and lung cancer associated with UPF intake. Competing risk regression was used to account for deaths from other causes and censoring.

RESULTS

During the follow-up of 1,379,655.5 person-years (median 16.8 years), 28,700 all-cause, 4092 CRDs, 2015 lung cancer and 1,536 COPD mortality occurred. A higher intake of UPF increased the risk of mortality from CRDs overall by 10% (HR 1.10; 95% CI 1.01, 1.22) and COPD by 26% (HR 1.26; 95% CI 1.06, 1.49) but not associated with lung cancer mortality risk (HR 0.97; 95% CI 0.84, 1.12). However, the risk of lung cancer increased by 16% (HR 1.16; 95% CI 1.01, 1.34) in the highest UPF intake after multiple imputation. Dose-response relationships existed for CRDs and COPD mortality but not lung cancer.

CONCLUSION

UPF consumption was associated with an increased risk of CRD mortality. The association between UPF consumption and lung cancer mortality is inconclusive and only significant when multiple imputation was applied.

Nanotechnology in toothpaste: Fundamentals, trends, and safety

Several studies have revealed that healthcare nanomaterials are widely used in numerous areas of dentistry, including prevention, diagnosis, treatment, and repair. Nanomaterials in dental cosmetics are utilized to enhance the efficacy of toothpaste and other mouthwashes. Nanoparticles are added to toothpastes for a variety of reasons, including dental decay prevention, remineralization, hypersensitivity reduction, brightening, and antibacterial qualities. In this review, the benefits and uses of many common nanomaterials found in toothpaste are outlined. Additionally, the capacity and clinical applications of nanoparticles as anti-bacterial, whitening, hypersensitivity, and remineralizing agents in the treatment of dental problems and periodontitis are discussed.

Alleviative Effect of Lactoferrin Interventions Against the Hepatotoxicity Induced by Titanium Dioxide Nanoparticles

The current study was designed to investigate the alleviative effect of lactoferrin interventions against the hepatotoxicity induced by titanium dioxide nanoparticles (TiO2-NPs). Thirty male Wistar rats were divided into six groups with 5 rats in each group. The first and second groups were intragastrically administered normal saline and TiO2-NPs (100 mg/kg body weight) as the negative control (NC) and TiO2-NP groups. The third, fourth, and fifth groups were intragastrically administered lactoferrin at concentrations of 100, 200, and 400 mg/kg body weight in addition to TiO2-NPs (100 mg/kg body weight). The sixth group was intragastrically administered Fuzheng Huayu (FZHY) capsules at a concentration of 4.6 g/kg body weight in addition to TiO2-NPs (100 mg/kg body weight) as the positive control group. After treatment for 4 weeks, the concentrations of lactoferrin were optimized based on the liver index and function results. Subsequently, the alleviative effects of lactoferrin interventions against TiO2-NP-induced hepatotoxicity in rat liver tissues, including the effects on histological damage, oxidative stress-related damage, inflammation, fibrosis, DNA damage, apoptosis, and gene expression, were investigated using histopathological, biochemical, and transcriptomic assays. The results showed that 200 mg/kg lactoferrin interventions for 4 weeks not only ameliorated the liver dysfunction and histopathological damage caused by TiO2-NP exposure but also inhibited the oxidative stress-related damage, inflammation, fibrosis, DNA damage, and apoptosis in the liver tissues of TiO2-NP-exposed rats. The transcriptomic results confirmed that the alleviative effect of lactoferrin interventions against the TiO2-NP exposure-induced hepatotoxicity was related to the activation of the PI3K/AKT signaling pathway.

8-Bromo-cAMP attenuates human airway epithelial barrier disruption caused by titanium dioxide fine and nanoparticles

Titanium dioxide fine particles (TiO2-FPs) and nanoparticles (TiO2-NPs) are the most widely used whitening pigments worldwide. Inhalation of TiO2-FPs and TiO2-NPs can be harmful as it triggers toxicity in the airway epithelial cells. The airway epithelium serves as the respiratory system's first line of defense in which airway epithelial cells are significant targets of inhaled pathogens and environmental particles. Our group previously found that TiO2-NPs lead to a disrupted barrier in the polarized airway epithelial cells. However, the effect of TiO2-FPs on the respiratory epithelial barrier has not been examined closely. In this study, we aimed to compare the effects of TiO2-FPs and TiO2-NPs on the structure and function of the airway epithelial barrier. Additionally, we hypothesized that 8-Bromo-cAMP, a cyclic adenosine monophosphate (cAMP) derivative, would alleviate the disruptive effects of both TiO2-FPs and TiO2-NPs. We observed increased epithelial membrane permeability in both TiO2-FPs and TiO2-NPs after exposure to 16HBE cells. Immunofluorescent labeling showed that both particle sizes disrupted the structural integrity of airway epithelial tight junctions and adherens junctions. TiO2-FPs had a slightly more, but insignificant impact on the epithelial barrier disruption than TiO2-NPs. Treatment with 8-Bromo-cAMP significantly attenuated the barrier-disrupting impact of both TiO2-FPs and TiO2-NPs on cell monolayers. Our study demonstrates that both TiO2-FPs and TiO2-NPs cause comparable barrier disruption and suggests a protective role for cAMP signaling. The observed effects of TiO2-FPs and TiO2-NPs provide a necessary understanding for characterizing the pathways involved in the defensive role of the cAMP pathway on TiO2-induced airway barrier disruption.

Investigation of TiO2 nanoparticle interactions in the fibroblast NIH-3T3 cells via liquid-mode atomic force microscope

Long before we recognized how significant they were, nanoparticles were already all around in the environment. Since then, an extensive number of synthetic nanoparticles have been engineered to improve our quality of life through rigorous scientific research on their uses in practically every industry, including semiconductor devices, food, medicine, and agriculture. The extensive usage of nanoparticles in commodities that come into proximity with human skin and internal organs through medicine has raised significant concerns over the years. TiO2 nanoparticles (NPs) are widely employed in a wide range of industries, such as cosmetics and food packaging. The interaction and internalization of TiO2 NPs in living cells have been studied by the scientific community for many years. In the present study, we investigated the cell viability, nanomechanical characteristics, and fluorescence response of NIH-3T3 cells treated with sterile DMEM TiO2 nanoparticle solution using a liquid-mode atomic force microscope and a fluorescence microscope. Two different sorts of response systems have been observed in the cells depending on the size of the NPs. TiO2 nanoparticles smaller than 100 nm support its initial stages cell viability, and cells internalize and metabolize NPs. In contrast, bigger TiO2 NPs (> 100 nm) are not completely metabolized and cannot impair cell survival. Furthermore, bigger NPs above 100 nm could not be digested by the cells, therefore hindering cell development, whereas below 100 nm TiO2 stimulated uncontrolled cell growth akin to cancerous type cells. The cytoskeleton softens as a result of particle internalization, as seen by the nanomechanical characteristics of the nanoparticle treated cells. According to our investigations, TiO2 smaller than 100 nm facilitates unintended cancer cell proliferation, whereas larger NPs ultimately suppress cell growth. Before being incorporated into commercial products, similar effects or repercussions that could result from employing different NPs should be carefully examined.

Malignant Neoplasms Arising in the Cardiac Pacemaker Cavity: A Systematic Review

Cancer is the abnormal proliferation of physiologically inadequate cells. Studies have identified the cardiac pacemaker pocket as a site of rare neoplasms. To evaluate the clinical outcomes, treatment, prognosis, and individualized management of tumors originating in the cardiac pacemaker pocket, a systematic review was conducted using case reports and case series available in the PubMed/Medline, Science Direct, Cochrane Central, LILACS, and Scientific Electronic Library Online (Scielo) databases. Pacemaker pocket tumors affected patients with a mean age of 72.9 years, with a higher incidence in males (76.9%, n = 10). The average time for neoplasm development was 4.4 years (54.07 months). The most prevalent model was Medtronic (38.4%, n = 5), with titanium (83.3%) being the most common metal composition. Chemotherapy was the most performed procedure among patients (38.4%), followed by radiation therapy (38.4%) and surgical tumor resection (30.7%). Six analyzed cases (46.1%) resulted in death, and four patients (30.7%) achieved a cure. Patients with pacemakers should be routinely evaluated for the occurrence of malignant tumors at the site of device implantation.

Genotoxicity Evaluation of Titanium Dioxide Nanoparticles In Vivo and In Vitro: A Meta-Analysis

BACKGROUND

Recent studies have raised concerns about genotoxic effects associated with titanium dioxide nanoparticles (TiO2 NPs), which are commonly used. This meta-analysis aims to investigate the potential genotoxicity of TiO2 NPs and explore influencing factors.

METHODS

This study systematically searched Chinese and English literature. The literature underwent quality evaluation, including reliability evaluation using the toxicological data reliability assessment method and relevance evaluation using routine evaluation forms. Meta-analysis and subgroup analyses were performed using R software, with the standardized mean difference (SMD) as the combined effect value.

RESULTS

A total of 26 studies met the inclusion criteria and passed the quality assessment. Meta-analysis results indicated that the SMD for each genotoxic endpoint was greater than 0. This finding implies a significant association between TiO2 NP treatment and DNA damage and chromosome damage both in vivo and in vitro and gene mutation in vitro. Subgroup analysis revealed that short-term exposure to TiO2 NPs increased DNA damage. Rats and cancer cells exhibited heightened susceptibility to DNA damage triggered by TiO2 NPs (p < 0.05).

CONCLUSIONS

TiO2 NPs could induce genotoxicity, including DNA damage, chromosomal damage, and in vitro gene mutations. The mechanism of DNA damage response plays a key role in the genotoxicity induced by TiO2 NPs.

Evaluation of the cytotoxic effect of titanium dioxide nanoparticles in human embryonic lung cells

Background/aim

Titanium dioxide nanoparticles are widely used in a variety of products, including sunscreens, paints, and ceramics. However, their increasing use has raised concerns about their potential health risks. Titanium dioxide nanoparticles have been shown to have the ability to enter the bloodstream and accumulate in various tissues, reaching the fetus via the placenta. The aim of this study was to investigate the cytotoxic effects of titanium dioxide nanoparticles on a human embryonic lung cell line (HEL 299/An1) and the formation of oxidative DNA damage.

Materials and methods

The cytotoxic effects of brookite-based titanium dioxide nanoparticles (<100 nm) were assessed using the 3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) assay for 24 and 48 h. Cell titanium levels were determined using inductively coupled plasma mass spectrometry. Oxidative DNA damage was assessed by measuring the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) as a biomarker.

Results

Titanium dioxide nanoparticles caused dose-dependent cytotoxicity in HEL 299/An1 cells. The IC50 values were 25.93 μM and 0.054 μM after 24 h and 48 h of exposure, respectively. Cell titanium levels were found to be 25,967 ppb after 24 h and 210,353 ppb after 48 h (p < 0.01). 8-OHdG was detected at 32.96 ng/mL after 24 h of exposure and 17.89 ng/mL after 48 h of exposure.

Conclusion

In our study, it was shown that titanium nanoparticles caused dose-dependent cytotoxicity and oxidative DNA damage in human embryonic lung cells. The nanoparticles also accumulated in cells and were taken up in higher amounts after 48 h of exposure. These findings suggest that titanium dioxide nanoparticles may pose a health risk, especially for pregnant women who may not be aware of their pregnancy. Therefore, it is important to take preventive measures to reduce exposure to these nanoparticles.

Progressing nanotechnology to improve targeted cancer treatment: overcoming hurdles in its clinical implementation

The use of nanotechnology has the potential to revolutionize the detection and treatment of cancer. Developments in protein engineering and materials science have led to the emergence of new nanoscale targeting techniques, which offer renewed hope for cancer patients. While several nanocarriers for medicinal purposes have been approved for human trials, only a few have been authorized for clinical use in targeting cancer cells. In this review, we analyze some of the authorized formulations and discuss the challenges of translating findings from the lab to the clinic. This study highlights the various nanocarriers and compounds that can be used for selective tumor targeting and the inherent difficulties in cancer therapy. Nanotechnology provides a promising platform for improving cancer detection and treatment in the future, but further research is needed to overcome the current limitations in clinical translation.

Antioxidants and mitochondrial/lysosomal protective agents reverse toxicity induced by titanium dioxide nanoparticles on human lymphocytes

Most of the literature has focused on titanium dioxide (TiO2) nanoparticles (NPs) toxicity, showing the importance of oxidative stress, mitochondrial dysfunction, and cell death in TiO2-induced toxicity. For this purpose, in the current study, we investigated the protective role of antioxidant and mitochondrial/lysosomal protective agents to minimize TiO2 NPs-induced toxicity in human lymphocytes. Human lymphocytes were obtained from heathy individuals and treated with different concentrations (80, 160, and 320 µg/mL) of TiO2 NPs, and then human lymphocytes preincubated with butylated hydroxytoluene (BHT), cyclosporin A (CsA), and chloroquine separately were exposed to TiO2 NPs for 6 h. In all the above-mentioned treated groups, adverse parameters such as cytotoxicity, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), lysosomal membrane destabilization, the levels of malondialdehyde (MDA), and glutathione (GSH) were measured. The results showed that TiO2 nanoparticles induced cytotoxicity through ROS formation, MMP collapse, lysosomal damages, depletion of GSH, and lipid peroxidation. However, BHT as an antioxidant, CsA as a mitochondrial permeability transition (MPT) pore sealing agent, and chloroquine as a lysosomotropic agent, significantly inhibited all the TiO2 NPs-induced cellular and organelle toxicities. Thus, it seems that antioxidant and mitochondrial/lysosomal protective agents are promising preventive strategies against TiO2 NPs-induced toxicity.

Getting fat and stressed: Effects of dietary intake of titanium dioxide nanoparticles in the liver of turbot Scophthalmus maximus

The extensive use of nanomaterials, including titanium dioxide nanoparticles (TiO2 NPs), raises concerns about their persistence in ecosystems. Protecting aquatic ecosystems and ensuring healthy and safe aquaculture products requires the assessment of the potential impacts of NPs on organisms. Here, we study the effects of a sublethal concentration of citrate-coated TiO2 NPs of two different primary sizes over time in flatfish turbot, Scophthalmus maximus (Linnaeus, 1758). Bioaccumulation, histology and gene expression were assessed in the liver to address morphophysiological responses to citrate-coated TiO2 NPs. Our analyses demonstrated a variable abundance of lipid droplets (LDs) in hepatocytes dependent on TiO2 NPs size, an increase in turbot exposed to smaller TiO2 NPs and a depletion with larger TiO2 NPs. The expression patterns of genes related to oxidative and immune responses and lipid metabolism (nrf2, nfκb1, and cpt1a) were dependent on the presence of TiO2 NPs and time of exposure supporting the variance in hepatic LDs distribution over time with the different NPs. The citrate coating is proposed as the likely catalyst for such effects. Thus, our findings highlight the need to scrutinize the risks associated with exposure to NPs with distinct properties, such as primary size, coatings, and crystalline forms, in aquatic organisms.

Estimation of genomic and mitochondrial DNA integrity in the renal tissue of mice administered with acrylamide and titanium dioxide nanoparticles

The Kidneys remove toxins from the blood and move waste products into the urine. However, the accumulation of toxins and fluids in the body leads to kidney failure. For example, the overuse of acrylamide and titanium dioxide nanoparticles (TiO2NPs) in many food and consumer products increases human exposure and risks; however, there are almost no studies available on the effect of TiO2NPs coadministration with acrylamide on the integrity of genomic and mitochondrial DNA. Accordingly, this study was conducted to estimate the integrity of genomic and mitochondrial DNA in the renal tissue of mice given acrylamide and TiO2NPs. To achieve this goal, mice were administrated orally TiO2NPs or/and acrylamide at the exposure dose levels (5 mg/kg b.w) and (3 mg/kg b.w), respectively, five times per week for two consecutive weeks. Concurrent oral administration of TiO2NPs with acrylamide caused remarkable elevations in the tail length, %DNA in tail and tail moment with higher fragmentation incidence of genomic DNA compared to those detected in the renal tissue of mice given TiO2NPs alone. Simultaneous coadministration of TiO2NPs with acrylamide also caused markedly high elevations in the reactive oxygen species (ROS) production and p53 expression level along with a loss of mitochondrial membrane potential and high decreases in the number of mitochondrial DNA copies and expression level of β catenin gene. Therefore, from these findings, we concluded that concurrent coadministration of acrylamide with TiO2NPs augmented TiO2NPs induced genomic DNA damage and mitochondrial dysfunction through increasing intracellular ROS generation, decreasing mitochondrial DNA Copy, loss of mitochondrial membrane potential and altered p53 and β catenin genes expression. Therefore, further studies are recommended to understand the biological and toxic effects resulting from TiO2NPs with acrylamide coadministration.

Improvement by application of three nanomaterials on flavor quality and physiological and antioxidant properties of tomato and their comparison

In recent years, it has been found that the flavor quality of tomato is continuously reduced compared with the original tomato varieties. Studies have found that nanomaterials can improve crop quality, but the differences and related mechanisms among different nanomaterials were not reported. In this study, nano-Se, nano-TiO2 and nano-CeO2 were spraying on tomato, and the effects of the three nanomaterials on the flavor quality and physiological and antioxidant properties of fruits were analyzed and compared. The results showed compared with nano-TiO2 and nano-CeO2, nano-Se showed more obvious positive effects. Nano-Se increased the size and weight of tomato fruits and the levels of soluble sugar, promoted the accumulation of photosynthetic pigment, decreased the content of titratable acid, and also changed the expression of related genes, finally making the fruit sweeter; it also promoted the accumulation of antioxidant substances and nutrients such as lycopene, ascorbic acid, salicylic acid, GSH, SOD and CAT and decreased the content of MDA, H2O2 and OFR thus improving the antioxidant performance of fruits; the contents of volatiles were also increased and the olfactory experience of tomato was improved. Nano-TiO2 and nano-CeO2 also improved the flavor quality and antioxidant properties of tomato, but the degree was lower than nano-Se. This experiment provided references for selecting more appropriate nanomaterials to improve tomato quality, and revealed the effects and mechanisms of different nanomaterials on tomato quality.

Histological and biochemical evaluation of the effects of silver nanoparticles (AgNps) versus titanium dioxide nanoparticles (TiO2NPs) on rat parotid gland

The unlimited use of nanoparticles (NPs) results in toxic impacts on different tissues. The current study aimed to compare the adverse effects of AgNPs and TiO2NPs on the parotid gland of adult male albino rats as regards the histopathological, immunohistochemical, and biochemical changes, exploring the possible underlying mechanisms and the degree of improvement after cessation of administration. Fifty-four adult male albino rats were divided into control group (I), AgNPs-injected group (II), and TiO2NPs-injected group (III). We measured the levels of tumor necrosis factor-alpha (TNF-α) and interleukin (IL-6) in the serum, and levels of MDA and GSH in parotid tissue homogenate. Quantitative real-time polymerase-chain reaction (qRT-PCR) was used to measure the expression levels of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1-α), nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4), mouse double minute 2 (MDM2), Caspase-3 Col1a1, and Occludin. Parotid tissue sections were examined by light microscope (Hematoxylin & Eosin and Mallory trichrome stains), electron microscope, and immunohistochemical examination of CD68 and anti-caspase-3 antibodies. Both NPs severely affected the acinar cells and damaged the tight junction between them by enhancing expression of the inflammatory cytokines, inducing oxidative stress, and disturbing the expression levels of the studied genes. They also stimulated fibrosis, acinar cell apoptosis, and inflammatory cells infiltration in parotid tissue. TiO2NPs effects were less severe than AgNPs. Cessation of exposure to both NPs, ameliorated the biochemical and structural findings with more improvement in TiO2NPs withdrawal. In conclusion: AgNPs and TiO2NPs adversely affected the parotid gland, but TiO2NPs were less toxic than AgNPs.

In Vitro Safety Assessment of In-House Synthesized Titanium Dioxide Nanoparticles: Impact of Washing and Temperature Conditions

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in food, cosmetics, and biomedical research. However, human safety following exposure to TiO2 NPs remains to be fully understood. The aim of this study was to evaluate the in vitro safety and toxicity of TiO2 NPs synthesized via the Stöber method under different washing and temperature conditions. TiO2 NPs were characterized by their size, shape, surface charge, surface area, crystalline pattern, and band gap. Biological studies were conducted on phagocytic (RAW 264.7) and non-phagocytic (HEK-239) cells. Results showed that washing amorphous as-prepared TiO2 NPs (T1) with ethanol while applying heat at 550 °C (T2) resulted in a reduction in the surface area and charge compared to washing with water (T3) or a higher temperature (800 °C) (T4) and influenced the formation of crystalline structures with the anatase phase in T2 and T3 and rutile/anatase mixture in T4. Biological and toxicological responses varied among TiO2 NPs. T1 was associated with significant cellular internalization and toxicity in both cell types compared to other TiO2 NPs. Furthermore, the formation of the crystalline structure induced toxicity independent of other physicochemical properties. Compared with anatase, the rutile phase (T4) reduced cellular internalization and toxicity. However, comparable levels of reactive oxygen species were generated following exposure to the different types of TiO2, indicating that toxicity is partially driven via non-oxidative pathways. TiO2 NPs were able to trigger an inflammatory response, with varying trends among the two tested cell types. Together, the findings emphasize the importance of standardizing engineered nanomaterial synthesis conditions and evaluating the associated biological and toxicological consequences arising from changes in synthesis conditions.

Assessing the Cytotoxicity of TiO2-x Nanoparticles with a Different Ti3+(Ti2+)/Ti4+ Ratio

Titanium dioxide (TiO₂) nanoparticles are promising biomedical agents characterized by good biocompatibility. In this study, we explored the cytotoxicity of TiO_2-x nanoparticles with a different Ti³⁺(Ti²⁺)/Ti⁴⁺ ratio and analyzed the efficiency of eryptosis indices as a tool in nanotoxicology. Two types of TiO_2-x nanoparticles (NPs) were synthesized by the hydrolysis of titanium alkoxide varying the nitric acid content in the hydrolysis mixture. Transmission electron microscopy (TEM) images show that 1-TiO_2-x and 2-TiO_2-x NPs are 5 nm in size, whereas X-ray photoelectron spectroscopy (XPS) reveals different Ti³⁺ (Ti²⁺)/Ti⁴⁺ ratios in the crystal lattices of synthesized NPs. 1-TiO_2-x nanoparticles contained 54% Ti⁴⁺, 38% Ti³⁺, and 8% Ti²⁺, while the relative amount of Ti⁴⁺ and Ti³⁺ in the crystal lattice of 2-TiO_2-x nanoparticles was 63% and 37%, respectively. Cell viability and cell motility induced by TiO_2-x nanoparticles were investigated on primary fibroblast cultures. Eryptosis modulation by the nanoparticles along with cell death mechanisms was studied on rat erythrocytes. We report that both TiO_2-x nanoparticles do not decrease the viability of fibroblasts simultaneously stimulating cell migration. Data from in vitro studies on erythrocytes indicate that TiO_2-x nanoparticles trigger eryptosis via ROS- (1-TiO_2-x) and Ca²⁺-mediated mechanisms (both TiO_2-x nanoparticles) suggesting that evaluation of eryptosis parameters is a more sensitive nanotoxicological approach for TiO_2-x nanoparticles than cultured fibroblast assays. TiO_2-x nanoparticles are characterized by low toxicity against fibroblasts, but they induce eryptosis, which is shown to be a promising tool for nanotoxicity screening. The Ti³⁺ (Ti²⁺)/Ti⁴⁺ ratio at least partly determines the cytotoxicity mechanisms for TiO_2-x nanoparticles.

Titanium Dioxide Nanoparticles Modulate Systemic Immune Response and Increase Levels of Reduced Glutathione in Mice after Seven-Week Inhalation

Titanium dioxide nanoparticles (TiO₂ NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO₂ NPs using a whole-body inhalation chamber model are rare. In this study, the profile of lymphocyte markers, functional immunoassays, and antioxidant defense markers were analyzed to evaluate the potential adverse effects of seven-week inhalation exposure to two different concentrations of TiO₂ NPs (0.00167 and 0.1308 mg TiO₂/m³) in mice. A dose-dependent effect of TiO₂ NPs on innate immunity was evident in the form of stimulated phagocytic activity of monocytes in low-dose mice and suppressed secretory function of monocytes (IL-18) in high-dose animals. The effect of TiO₂ NPs on adaptive immunity, manifested in the spleen by a decrease in the percentage of T-cells, a reduction in T-helper cells, and a dose-dependent decrease in lymphocyte cytokine production, may indicate immunosuppression in exposed mice. The dose-dependent increase in GSH concentration and GSH/GSSG ratio in whole blood demonstrated stimulated antioxidant defense against oxidative stress induced by TiO₂ NP exposure.

Prospects of TiO2-based photocatalytic degradation of microplastic leachates related disposable facemask, a major COVID-19 waste

COVID-19 is one of the serious catastrophes that have a substantial influence on human health and the environment. Diverse preventive actions were implemented globally to limit its spread and transmission. Personnel protective equipment (PPE) was an important part of these control approaches. But unfortunately, these types of PPE mainly comprise plastics, which sparked challenges in the management of plastic waste. Disposable face masks (DFM) are one of the efficient strategies used across the world to ward off disease transmission. DFMs can contribute to micro and nano plastic pollution as the plastic present in the mask may degrade when exposed to certain environmental conditions. Microplastics (MPs) can enter the food chain and devastate human health. Recognizing the possible environmental risks associated with the inappropriate disposal of masks, it is crucial to avert it from becoming the next plastic crisis. To address this environmental threat, titanium dioxide (TiO2)-based photocatalytic degradation (PCD) of MPs is one of the promising approaches. TiO2-based photocatalysts exhibit excellent plastic degradation potential due to their outstanding photocatalytic ability, cost efficiency, chemical, and thermal stability. In this review, we have discussed the reports on COVID-19 waste generation, the limitation of current waste management techniques, and the environmental impact of MPs leachates from DFMs. Mainly, the prominence of TiO2 in the PCD and the applications of TiO2-based photocatalysts in MPs degradation are the prime highlights of this review. Additionally, various synthesis methods to enhance the photocatalytic performance of TiO2 and the mechanism of PCD are also discussed. Furthermore, current challenges and the future research perspective on the improvement of this approach have been proposed.

Estimation of genotoxicity, apoptosis and oxidative stress induction by TiO2 nanoparticles and acrylamide subacute oral coadministration in mice

Acrylamide is used in the industry and can be a by-product of high-temperature food processing which has toxic potential in various tissues, and titanium dioxide nanoparticles (TiO₂NPs) are widely used in toothpaste, sweets, food perseveration, chewing gum and medicines. Consequently, humans are daily exposed to large amounts of acrylamide and TiO₂NPs mainly through food intake. However, limited studies are available on the effect of simultaneously intake of acrylamide and TiO₂NPs on the integrity of genomic DNA and the induction of apoptosis in brain tissues. Therefore, this study estimated the influence of acrylamide coadministration on TiO₂NPs induced genomic instability and oxidative stress in the brain tissues of mice. To achieve this, mice were orally administrated acrylamide (3 mg/kg b.w) or/and TiO₂NPs (5 mg/kg b.w) for two successive weeks (5 days per week). The comet assay results showed that concurrent oral administration of acrylamide and TiO₂NPs strongly induced single- and double stranded DNA breaks, and that the level of reactive oxygen species (ROS) was also highly elevated within neural cells after simultaneous oral intake of acrylamide and TiO₂NPs compared to those observed after administration of acrylamide or/TiO₂NPs alone. Moreover, oral co-administration of acrylamide with TiO₂NPs increased apoptotic DNA damage to neurons by upregulating the expression levels of P53, TNF-α, IL-6 and Presenillin-1 genes compared to groups administered TiO₂NPs. Therefore, from these results, the present study concluded that coadministration of acrylamide renders TiO₂NPs more genotoxic and motivates apoptotic DNA damage and oxidative stress induced by TiO₂NPs in brain cells, and thus it is recommended to avoid concurrent oral acrylamide administration with TiO₂NPs.

TiO2 Nanoparticles and Their Effects on Eukaryotic Cells: A Double-Edged Sword

Nanoparticulate TiO₂ (TiO₂ NPs) is a widely used material, whose potential toxicity towards eukaryotic cells has been addressed by multiple studies. TiO₂ NPs are considered toxic due to their production of reactive oxygen species (ROS), which can, among others, lead to cellular damage, inflammatory responses, and differences in gene expression. TiO₂ NPs exhibited toxicity in multiple organs in animals, generating potential health risks also in humans, such as developing tumors or progress of preexisting cancer processes. On the other hand, the capability of TiO₂ NPs to induce cell death has found application in photodynamic therapy of cancers. In aquatic environments, much has been done in understanding the impact of TiO₂ on bivalves, in which an effect on hemocytes, among others, is reported. Adversities are also reported from other aquatic organisms, including primary producers. These are affected also on land and though some potential benefit might exist when it comes to agricultural plants, TiO₂ can also lead to cellular damage and should be considered when it comes to transfer along the food chain towards human consumers. In general, much work still needs to be done to unravel the delicate balance between beneficial and detrimental effects of TiO₂ NPs on eukaryotic cells.

Prenatal exposure to titanium dioxide nanoparticles induces persistent neurobehavioral impairments in maternal mice that is associated with microbiota-gut-brain axis

Gestational exposure to titanium dioxide nanoparticles (TiO₂NPs) has been widely reported to have deleterious effects on the brain functions of offspring. However, little attention has been paid to the neurotoxic effects of TiO₂NPs on maternal body after parturition. The pregnant mice were orally administrated with TiO₂NPs at 150 mg/kg from gestational day 8-21. The potential effects of TiO₂NPs on the neurobehaviors were evaluated at postnatal day 60. The gut microbiota, morphological alterations of intestine and brain, and other indicators that involved in gut-brain axis were all assessed to investigate the underlying mechanisms. The results demonstrated that exposure to TiO₂NPs during pregnancy caused the persistent neurobehavioral impairments of maternal mice after delivery for 60 days, mainly including behavioural changes, pathological changes in hippocampus, cortex and intestine. Our data also showed that persistent dysfunction and tissue injuries were probably associated with the disruption of gut-brain axis, manifested by the shift in the composition of gut microbial community, alteration of Sstr1, inhibition of enteric neurons and reduction of diamine oxidase contents in maternal mice. These findings provide a novel insight that regulation of gut microecology may be an alternative strategy for the protection against the neurotoxicity of TiO₂NPs in pregnant women.

Multi-omics analysis reveals the molecular responses of Torreya grandis shoots to nanoplastic pollutant

Micro/nanoplastic has become an emerging pollutant of global concern. At present, ecotoxic researches on micro/nanoplastics mostly focus on marine aquatic organisms and freshwater algae. Research on the ecological impacts of plastics on higher terrestrial plants, especially on forest plants, is relatively limited. Torreya grandis cv. Merrillii, a species of conifer in the family Taxaceae, is a unique and economically valuable tree species in China. The physiological and biochemical responses of T. grandis seedlings to polystyrene nanoplastics (PSNPs) with a diameter of 100 nm were systematically studied inthe present study. The results showed that nanoplastics enhanced the accumulation of the thiobarbituric acid reactive substance and the activities of catalase and peroxidase. The concentrations of iron, sulfur, and zinc were reduced after nanoplastic exposure. PSNP treatment had an important effect on a series of chemical and genetic indicators of T. grandis, includingantioxidants, small RNA, gene transcription, protein expressions, and metabolite accumulation. Multi-omic analysis revealed that PSNPs modulate terpenoid- and flavonoid-biosynthesis pathways by regulating small RNA transcription and protein expression. Our study provided novelty insights into the responses of forest plants to nanoplastic treatment.

Effects of Selected Metal Nanoparticles (Ag, ZnO, TiO2) on the Structure and Function of Reproductive Organs

Various studies have shown that the reproductive organs are highly sensitive to toxic elements found in the environment. Due to technological progress, the use of nanoparticles has become more common nowadays. Nanoparticles are used for drug delivery because their dimensions allow them to circulate throughout the body and enter directly into the cell. Antimicrobial properties are increasingly used in the manufacture of medical devices, textiles, food packaging, cosmetics, and other consumer products. Nanoparticles provide several benefits, but aspects related to their effects on living organisms and the environment are not well known. This review summarizes current in vivo, and in vitro animal studies focused on the evaluation of toxicity of selected metal nanoparticles (Ag, ZnO, TiO₂) on male and female reproductive health. It can be concluded that higher concentrations of metal nanoparticles in the male reproductive system can cause a decrease in spermatozoa motility, viability and disruption of membrane integrity. Histopathological changes of the testicular epithelium, infiltration of inflammatory cells in the epididymis, and prostatic hyperplasia have been observed. Nanoparticles in the female reproductive system caused their accumulation in the ovaries and uterus. Metal nanoparticles most likely induce polycystic ovary syndrome and follicular atresia, inflammation, apoptosis, and necrosis also occurred.

Relationship between maternal exposure to heavy metal titanium and offspring congenital heart defects in Lanzhou, China: A nested case-control study

Background

Previous studies have found that exposure to heavy metals increased the incidence of congenital heart defects (CHDs). However, there is a paucity of information about the connection between exposure to titanium and CHDs. This study sought to examine the relationship between prenatal titanium exposure and the risk of CHDs in offspring.

Methods

We looked back on a birth cohort study that was carried out in our hospital between 2010 and 2012. The associations between titanium exposure and the risk of CHDs were analyzed by using logistic regression analysis to investigate titanium concentrations in maternal whole blood and fetal umbilical cord blood.

Results

A total of 97 case groups and 194 control groups were included for a nested case-control study. The [P₅₀ (P₂₅, P₇₅)] of titanium were 371.91 (188.85, 659.15) μg/L and 370.43 (264.86, 459.76) μg/L in serum titanium levels in pregnant women and in umbilical cord serum titanium content in the CHDs group, respectively. There was a moderate positive correlation between the concentration of titanium in pregnant women's blood and that in umbilical cord blood. A higher concentrations of maternal blood titanium level was associated with a greater risk of CHDs (OR 2.706, 95% CI 1.547–4.734), the multiple CHDs (OR 2.382, 95% CI 1.219–4.655), atrial septal defects (OR 2.367, 95% CI 1.215–4.609), and patent ductus arteriosus (OR 2.412, 95% CI 1.336–4.357). Dramatically higher concentrations of umbilical cord blood levels had an increased risk of CHDs and different heart defects.

Conclusion

Titanium can cross the placental barrier and the occurrence of CHDs may be related to titanium exposure.

Ti Ions Induce IL-1β Release by Activation of the NLRP3 Inflammasome in a Human Macrophage Cell Line

The aim of the present study was to investigate whether titanium (Ti)-induced release of interleukin (IL)-1β acts through the assembly of the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome. In addition, we examined whether particulate Ti or TiO₂ activates the same intracellular pathways with the assembly of the NLRP3 inflammasome as Ti ions. Ti ions are known to induce IL-1β maturation and release by the formation of metal-protein aggregates. Wild-type THP-1 (wt.) cells and NLRP3^- and ASC^- (apoptosis-associated speck-like protein containing caspase recruitment domain (CARD)) knockdown cells were used in the experimental analyses. Macro- and nanoparticles (NPs) of both Ti and TiO₂ were used as test agents. IL-1β release as a biomarker for inflammasome activation and cell viability was also analyzed. Periodate-oxidized adenosine triphosphate (oATP) was used to attenuate downstream signaling in NLRP3 inflammasome activation. Cellular uptake of Ti was examined using transmission electron microscopy. Cells exposed to the Ti-ion solution showed a dose-dependent increase in the release of IL-1β; conversely, exposure to particulate Ti did not result in increased IL-1β release. Cell viability was not affected by particulate Ti. Knockdown cells exposed to Ti showed a statistically significant reduction in the release of IL-1β compared with wt. cells (p < 0.001). Cellular uptake was detected in all Ti mixtures, and aggregates with various structures were observed. Ti ion-induced release of bioactive IL-1β in THP-1 cells involves the assembly of the NLRP3 inflammasome.

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety.

Experimental Investigation on Solar–Thermal Conversion and Migration Characteristics of Nanofluids

Solar–thermal conversion and migration characteristics of nanofluids have attracted intensive attention recently. Due to the strong absorption of solar energy, solar collectors with nanofluids have wide applications in many areas including desalination and power generation. Researchers have mainly focused on the macroscopic performance of nanofluids in solar collectors, but the nanoparticles’ migration characteristics with vapor during phase transformation have not been further investigated. Therefore, an experimental investigation on solar–thermal conversion characteristics of nanofluids and migration characteristics with vapor during phase transformation was conducted in this work, in order to verify the enhancement effect of nanoparticles on solar energy absorption and explore the nanoparticles’ migration behavior with vapor. It was found that part of Ag nanoparticles migrate out of the nanofluids with generated vapor by boiling nanofluids, and most of the nanoparticles remained in the nanofluids. In addition, more Ag nanoparticles migrated with vapor with the increased heating power. The concentration of migrated nanofluids was 20.58 ppm with a power of 16.2 W and 31.39 ppm with a power of 20 W. The investigation pointed out the potential danger of nanofluids in the process of utility and provided a reference for the standardized application of nanofluids.

A review of multilayer and composite films and coatings for active biodegradable packaging

Active biodegradable packaging are being developed from biodegradable biopolymers which may solve the environmental problems caused by petroleum-based materials (plastics), as well as improving the shelf life, quality, nutritional profile, and safety of packaged food. The functional performance of active ingredients in biodegradable packaging can be extended by controlling their release profiles. This can be achieved by incorporating active ingredients in sandwich-structured packaging including multilayer and composite packaging. In multilayer materials, the release profile can be controlled by altering the type, structure, and thickness of the different layers. In composite materials, the release profile can be manipulated by altering the interactions of active ingredients with the surrounding biopolymer matrix. This article reviews the preparation, properties, and applications of multilayer and composite packaging for controlling the release of active ingredients. Besides, the basic theory of controlled release is also elaborated, including diffusion, swelling, and biodegradation. Mathematical models are presented to describe and predict the controlled release of active ingredients from thin films, which may help researchers design packaging materials with improved functional performance.

MicroRNAs as a Suitable Biomarker to Detect the Effects of Long-Term Exposures to Nanomaterials. Studies on TiO2NP and MWCNT

The presence of nanomaterials (NMs) in the environment may represent a serious risk to human health, especially in a scenario of chronic exposure. To evaluate the potential relationship between NM-induced epigenetic alterations and carcinogenesis, the present study analyzed a panel of 33 miRNAs related to the cell transformation process in BEAS-2B cells transformed by TiO₂NP and long-term MWCNT exposure. Our battery revealed a large impact on miRNA expression profiling in cells exposed to both NMs. From this analysis, a small set of five miRNAs (miR-23a, miR-25, miR-96, miR-210, and miR-502) were identified as informative biomarkers of the transforming effects induced by NM exposures. The usefulness of this reduced miRNA battery was further validated in other previously generated transformed cell systems by long-term exposure to other NMs (CoNP, ZnONP, MSiNP, and CeO₂NP). Interestingly, the five selected miRNAs were consistently overexpressed in all cell lines and NMs tested. These results confirm the suitability of the proposed set of mRNAs to identify the potential transforming ability of NMs. Particular attention should be paid to the epigenome and especially to miRNAs for hazard assessment of NMs, as wells as for the study of the underlying mechanisms of action.

Acute titanium dioxide nanoparticles exposure impaired spatial cognitive performance through neurotoxic and oxidative mechanisms in Wistar rats

CONTEXT

Titanium dioxide nanoparticles (TiO2-NPs) are used in many commercial products. However, their effects on human and animal organism remained to be clarified.

OBJECTIVE

The present study aimed to investigate the effects of TiO2-NPs on the behavioural performance, monoamine neurotransmitters and oxidative stress in the rat brain.

MATERIAL AND METHODS

Rats were injected intravenously with a single dose of TiO2-NPs (20 mg/kg body weight) and were subjected to cognitive and emotional tests using Morris water maze and elevated plus maze.

RESULTS

Cognitive capacity as well as the emotional reactivity were significantly disrupted, in TiO2-NPs-administered rats compared to control group. These behavioural effects were correlated with changes in brain neurotransmitter contents reflected by a significant increase in dopamine and a decrease in serotonin levels. TiO2-NPs also induced oxidative stress in the brain manifested by increased levels of H2O2 and malondialdehyde, associated with antioxidant enzymes activities disturbance, in particular, superoxide dismutase and catalase activities. Moreover, TiO2-NPs administration caused histological damages in the brain tissue with abundant lymphocytic clusters, capillary dilations, vascular congestion and oedema.

CONCLUSIONS

Acute intravenous injection of TiO2-NPs impaired behaviour performances through brain biochemical and structural changes and precautions should be taken to their usage in food additive and medical applications.

Influence of Titanium Dioxide Nanoparticles on Human Health and the Environment

Nanotechnology has enabled tremendous breakthroughs in the development of materials and, nowadays, is well established in various economic fields. Among the various nanomaterials, TiO₂ nanoparticles (NPs) occupy a special position, as they are distinguished by their high availability, high photocatalytic activity, and favorable price, which make them useful in the production of paints, plastics, paper, cosmetics, food, furniture, etc. In textiles, TiO₂ NPs are widely used in chemical finishing processes to impart various protective functional properties to the fibers for the production of high-tech textile products with high added value. Such applications contribute to the overall consumption of TiO₂ NPs, which gives rise to reasonable considerations about the impact of TiO₂ NPs on human health and the environment, and debates regarding whether the extent of the benefits gained from the use of TiO₂ NPs justifies the potential risks. In this study, different TiO₂ NPs exposure modes are discussed, and their toxicity mechanisms—evaluated in various in vitro and in vivo studies—are briefly described, considering the molecular interactions with human health and the environment. In addition, in the conclusion of this study, the toxicity and biocompatibility of TiO₂ NPs are discussed, along with relevant risk management strategies.