Effects Of Titanium Dioxide Nanoparticles Research Articles

Acute effects of Titanium dioxide Nanoparticles in soil bacteria, Fungi and Actinomycetes

The Nanotechnology industry is growing rapidly, leading to concerns about the potential ecological consequences of the release of nonmaterial to the environment. Titanium dioxide nanoparticles (TiO2 NPs) are widely used in commercial products such as sunscreens and toothpastes, industrial products like paints, lacquers and paper, and in photocatalytic processes such as water treatment. Also, TiO2 NPs are indirectly discharged in agricultural soils through irrigation or sewage-sludge application and directly as nanofertilizers or nanopesticides. Soil microorganisms are key contributors to nutrient cycling and are essential for the maintenance of healthy soils and sustainable agriculture. Although the antimicrobial effects of a broad range of nanoparticulate substances have been characterised in vitro, little is known about the impact of these compounds on microbial communities in environments such as soil. This study focused on the acute effects of TiO2 NPs on soil microbial communities such as bacteria, Fungi and Actinomycetes. This research revealed substantial shifts in bacterial, fungal and actinomycetes community composition in soils amended with TiO2. The TiO2 NPs exerted an adverse effect on the microbial population, causing the reduction of bacteria, Fungi and Actinomycetes in the substrate. The viability of the microbial population was reduced at the high concentration (50 mg kg−1) of TiO2. Results demonstrate that microbial communities differed in their sensitivity to TiO2 NPs with its various concentration and the release of TiO2 NPs to the environment has the potential to alter the composition of these microbial communities, which could have implications for the stability and function of soil ecosystems

Effect of Titanium Dioxide Nanoparticles (TiO2NPs) on Leishmania parasite in vitro

The study included detecting the effect of nanoparticles of titanium dioxide nanoparticles (TiO2NPs) with different concentrations (0.5, 1, 5, 10) mg/ml and for two sizes (100, 10) nm on parasites of Leishmania tropica in vitro. The results showed that titanium dioxide nanoparticles (TiO2NPs) have an effect on the parasite with an inverse relationship between growth rate, concentrations of nanoparticles and the exposure period as well as the size of the nanoparticles. The sizes used of titanium dioxide nanoparticles (TiO2NPs) with all their concentrations had a toxic effect on Leishmania promastigote developing in culture media at 48 and 72 hours compared to the control group and that the concentrations of size 10 nm were more effective than concentrations of size of 100 nm on the growth of the parasite during the same time peroids used, and this gives an indication of the importance of using small sizes of titanium dioxide nanoparticles (TiO2NPs) as an anti-growth of Leishmania parasites.

Surface smoothening and formation of nano-channels improved mono-selectivity and antifouling property in TiO2 incorporated cation exchange membrane

Green liquor solution (GLS) is waste pollutant from pulp and paper mills. Causticization process is a common treatment method for GLS, which is energy intensive and environmentally unsafe, because of high operating cost, and solid waste generation. We reported synergetic effect of titanium dioxide nanoparticle (TiO2) incorporated sulfonated PEEK, on the performance cation exchange membrane (CEM), for producing NaOH from industrial GLS by electro-electroldiaysis (EED). Reported composite CEM was studied for morphology, physicochemical, electrochemical properties. The counter-ion transport number, stability and antifouling properties of CEM were significantly improved after the addition of TiO2 nanoparticles in the sulfonated PEEK membrane matrix. Two compartment EED cell (active membrane area: 66 cm2) was used to perform the experiments for producing NaOH using industrial GLS at 60 mA·cm−2 constant current density. The reported results shed light on production of NaOH along with prevention of sulfur scaling in treatment of wood based pulp and paper mills GLS stream. The modified membrane named SPK-T-5 (5 wt% of TiO2) by utilizing containing sulfonated polymer matrix outperforms an increasing trend of NaOH production along with notable sulfur antifouling. The obtained research outcomes are expected to be a valuable source for NaOH production with the aim of zero solid discharge practice for pulp and paper mills.

Effects of Titanium Dioxide Nanoparticles on Cell Growth and Migration of A549 Cells under Simulated Microgravity

With the increasing application of nanomaterials in aerospace technology, the long-term space exposure to nanomaterials especially in the space full of radiation coupled with microgravity condition has aroused great health concerns of the astronauts. However, few studies have been conducted to assess these effects, which are crucial for seeking the possible intervention strategy. Herein, using a random positioning machine (RPM) to simulate microgravity, we investigated the behaviors of cells under simulated microgravity and also evaluated the possible toxicity of titanium dioxide nanoparticles (TiO2 NPs), a multifunctional nanomaterial with potential application in aerospace. Pulmonary epithelial cells A549 were exposed to normal gravity (1 g) and simulated gravity (~10−3 g), respectively. The results showed that simulated microgravity had no significant effect on the viability of A549 cells as compared with normal gravity within 48 h. The effects of TiO2 NPs exposure on cell viability and apoptosis were marginal with only a slightly decrease in cell viability and a subtle increase in apoptosis rate observed at a high concentration of TiO2 NPs (100 μg/mL). However, it was observed that the exposure to simulated microgravity could obviously reduce A549 cell migration compared with normal gravity. The disruption of F-actin network and the deactivation of FAK (Tyr397) might be responsible for the impaired mobility of simulated microgravity-exposed A549 cells. TiO2 NPs exposure inhibited cell migration under two different gravity conditions, but to different degrees, with a milder inhibition under simulated microgravity. Meanwhile, it was found that A549 cells internalized more TiO2 NPs under normal gravity than simulated microgravity, which may account for the lower cytotoxicity and the lighter inhibition of cell migration induced by the same exposure concentration of TiO2 NPs under simulated microgravity at least partially. Our study has provided some tentative information on the effects of TiO2 NPs exposure on cell behaviors under simulated microgravity.

Effect oF TiO2 Nanoparticles and Curcumin on Sperm Parameters in Response to Temperature-Induced Stress in Scrotal Hyperthermia Rats: Role of miR455

Background: Temperature changes cause testicular dysfunction. It has been observed that testicular hyperthermia leads to oxidative stress and as a result a severe reduction in testicular parameters. Causes a severe reduction in Sperm parameters to become oxidative due to stress. Recently, natural plant materials and magnetic nanoparticles have been considered. In the internal mitochondrial apoptosis pathway, gen bcl2 is a target of miR455. Objectives: The present study aimed to investigate the effects of titanium dioxide nanoparticles and improve their impacts by using the antioxidant curcumin on sperm parameters by investigating changes in expression miR455 in response to temperature-induced stress in scrotal hyperthermia rats. Methods: After preparation, the rats were placed in a hot water bath at 43°C. for 30 minutes for six consecutive days. The rats were then divided into eight groups. We used TiO2 nanoparticles at a concentration of 0.03 mg/kg of body weight and curcumin at a concentration of 0.02 mg/kg of body weight. After killing the animals, such parameters of sperm as viability, concentration, motility, and morphology of spermatozoa were studied. RNA extraction and cDNA synthesis were performed using appropriate kits. A gene primer was designed and RT-PCR was used to assess gene expression. The t-test and ANOVA were used to examine differences between different groups. Data analysis was performed using Prism8 software and SPSS version 26. Results: The results showed that miR455 expression was lower in the treatment groups and was associated with curcumin (P < 0.05). A positive effect of curcumin on improving sperm parameters in rats with scrotum hyperthermia and a negative and toxic effect of TiO2 nanoparticles were shown. However, a significant improvement in sperm parameters was observed when rats were given TiO2 nanoparticles along with curcumin. Conclusions: The changes in the expression miR455, shown in curcumin have controlled the damage to TiO2 nanoparticles. It seems that miRNA455 can be used as a marker to predict sperm health status. So Curcumin can play a protective role in reducing the toxic effects of testicular hyperthermia as well as titanium dioxide nanoparticles.

Effect of titanium dioxide nanoparticles on histone modifications and histone modifying enzymes expression in human cell lines

Titanium dioxide (TiO2) nanoparticles are widely manufactured, with a range of applications in consumer products. Significant toxicity of TiO2 nanoparticles has, however, been recognized, suggesting considerable risk to human health. To evaluate fully their toxicity, assessment of the epigenetic action of these nanoparticles is critical. However, only few studies are available examining the capability of nanoparticles to alter epigenetic integrity. In the present study, the effect of TiO2 nanoparticles exposure on histone modifications, a major epigenetic mechanism, was investigated in human colorectal (Caco-2) and lung (NL20) epithelial cell lines. Histone H3 and H4 modifications were assessed by array analysis using the EpiQuickTM Histone H3 or H4 Modification Multiplex Assay. Seventeen histone modifications were identified with altered levels after exposure to TiO2 nanoparticles. Changes in several selected histone modifications (Caco-2 cells: H3cit, H3K9me3, H3K27me3, H3K36me3, H3K9ac, and H4K8ac; NL20 cells: H3K4me3, H3K9me3, H3K27me3, H3K9ac, and H3K18ac) were verified by Western blot analysis. The results also revealed aberrant expression of histone modifying enzymes in TiO2 exposed cells. Expression levels were determined by array analysis using the Human Epigenetic Chromatin Modification Enzymes RT2 Profiler™ PCR Array, with 12 genes identified in both Caco-2 cells and NL20 cells. qRT-PCR analysis confirmed the array results for several selected histone modifying enzyme genes (ASH1L, CARM1, EHMT2, HAT1, HDAC9, KMT2E, NCOA1, SETDB2, and USP16). The findings from this study clearly demonstrate the impact of TiO2 nanoparticles exposure on histone modification in two human cell lines, supporting potential involvement of this epigenetic mechanism in the toxicity of TiO2 nanoparticles. Hence, for complete assessment of potential risk from nanoparticle exposure, epigenetic studies are critical.

Histopathological effects of titanium dioxide nanoparticles on the liver of Japanese quail Coturnix coturnix japonica

Titanium dioxide nanoparticles have multiple beneficial uses, as they are used in many medical, industrial, economic, and other fields. Despite these many benefits, it is not without harm to humans and animals if used without control. Therefore, the present study aimed to discover the histopathological effects of Titanium dioxide nanoparticles on the liver of Japanese quail, Coturnix coturnix japonica. The study included three groups, the first group, the control group, which were dosed with distilled water for four continuous days, and the second and third experimental groups, which were dosed with Titanium dioxide nanoparticles at a concentration of 20 and 40 mg/kg, respectively. Four, fourteen, thirty and sixty days after the experiment began, the birds were sacrificed. The results showed the emergence of many histological lesions in the liver of birds of the two experimental groups, to varying degrees, in the four periods, among the most prominent tissue lesions that appeared in the second experimental group, the emergence of necrosis, hemorrhage, vacuolation, congestion, ballooning swelling, in addition to infiltration of inflammatory cells. While in the third experimental group, histopathological lesions appeared similar to second group, in addition to sinuses dilatation, Kupffer cells hypertrophy, hepatocyte enlargement, and necrosis of the walls of blood vessels and bile ducts. The study concluded that direct exposure to Titanium dioxide nanoparticles leads to damage to the liver tissue of these birds, which may affect its function and thus endanger its life.

The effect of titanium dioxide nanoparticles with or without platelet rich plasma on the healing of mandibular bony defects in rabbits

Objectives This experimental study was designed to evaluate the effect of titanium dioxide nanoparticles (TiO2NPs) alone or in combination with platelet rich plasma (PRP) on the healing of experimentally created critical-size bony defects in the rabbit's mandible histologically, immunohistochemically using matrix metalloproteinase-9 and vascular endothelial growth factor antibodies and histomorphometrically. Materials and methods Sixteen rabbits were included in the study, where three identical critical-size circular bony defects, two in the right side and one in the left side of the mandible of each rabbit, were created; group I: comprises 16 intraosseous defects (the mesial defect in the right side of the mandible of each rabbit) with no filler, group II: comprises 16 intraosseous defects (the distal defect in the right side of the mandible of each rabbit) filled with TiO2NPs powder mixed with saline, group III: comprises 16 intraosseous defects (the defect in the left side of the mandible of each rabbit) filled with TiO2NPs powder mixed with PRP. Samples were collected from the surgical sites of the experimental defects at 2 and 6 weeks. Results Histologically and histomorphometrically: the amount of newly formed bone was superior and significant in group III when compared with group II and group I at 2 and 6 weeks interval. Immunohistochemically group III showed superior and statistically significant increase in the vascular endothelial growth factor expression levels and matrix metalloproteinase-9 immunolabeling when compared with group II and group I. Conclusion TiO2NPs can be considered a promising material for bone regeneration alone or when combined with PRP.

The Restorative Effect of Titanium Dioxide Nanoparticles Synthesized with Origanum vulgare L., Carvacrol, Hypericum perforatum L., and Hypericin Loaded in Calcium Alginate Scaffold on Staphylococcus aureus-Infected Ulcers in Diabetic Rats

The Restorative Effect of Titanium Dioxide Nanoparticles Synthesized with Origanum vulgare L., Carvacrol, Hypericum perforatum L., and Hypericin Loaded in Calcium Alginate Scaffold on Staphylococcus aureus-Infected Ulcers in Diabetic Rats

Physiological and Hormonal Effects of Titanium Dioxide Nanoparticles on Thyroid Function and the Impact on Bodyweight in Male Rats

Fifty-four Sprague-Dawley albino adult male rats were classified into three main groups each of 18 rats treated for a particular duration (1,2, and 4) weeks respectively. Each group was subdivided into three subgroups each of six rats treated as follows; group (1) serve as normal control, group (2, and 3) intra-peritoneal treated with TiO2NPs (50,200) mg/kg respectively, body *weight of all rats was measured before and after the experiment, then rats were dissected at the end of each experiment and the weights of the thyroid was measured. The result showed a highly significant decrease (p<0.01) in thyroid gland weight, a highly significant increase (p<0.01) in body weights and TSH, while a highly significant decrease (p<0.01) inT3 and T4 was observed in all different doses (50,200) mg/kg at durations 1,2 and 4 weeks. So, this study confirms body weight gain is associated with thyroid dysfunction.

Effect of titanium dioxide nanoparticles and thyme essential oil on the quality of the chicken fillet

Effect of titanium dioxide nanoparticles and thyme essential oil on the quality of the chicken fillet

An In Vitro Evaluation of The Effect of Titanium Dioxide Nanoparticle on The Shear Bond Strength and Antimicrobial Property of Orthodontic Adhesive: A Systematic Review and Meta-Analysis

Objective: The objective of this review was to systematically analyse available literature on the effects of titanium dioxide nanoparticles (TiO₂ NPs) in improving the antimicrobial activity and shear bond strength when incorporated in orthodontic adhesives. Methods: All invitro studies that have evaluated the shear bond strength and the antimicrobial activity of TiO2 NPs infiltrated orthodontic adhesive were included in this review. A comprehensive search in 5 electronic databases namely, Google scholar, PUBMED, EMBASE, Cochrane and Web of science were done up to January 2023. Using the reference method for invitro studies, the Risk of bias ROB was evaluated. Meta-analysis using Random Effects Model was performed for assessing the antimicrobial activity against S. mutans, C. albicans and L. Acidophilus. Results: All the included studies had a moderate risk of bias. On qualitative analysis, a significant antimicrobial effect against Streptococcus mutans and Lactobacillus acidophilus and a non-significant shear bond strength of TiO2 infiltrated orthodontic adhesive was reported. The meta-analysis revealed a significant overall antimicrobial effect and non-significant shear bond strength values with a high heterogeneity. Conclusion: An overall significant antimicrobial effect of TiO₂ infiltrated orthodontic adhesive against S. mutans and L. Acidophilus was noted but with a high heterogeneity and a moderate risk of bias. An overall non-significant shear bond strength of TiO₂ infiltrated orthodontic adhesive was noted but with a high heterogeneity and a moderate risk of bias.

التأثيرات الفسيولوجية والهرمونية لجزيئات ثنائي أوكسيد التيتانيوم النانويه على وظائف الغدة الدرقية والكلى

تُستخدم الجسيمات النانوية لثاني أكسيد التيتانيوم (TiO2 NPs) بشكل عام في أنواع مختلفة من التطبيقات مثل صناعة البلاستيك، وصناعة الورق، والدهانات، ومعجون الأسنان، ومستحضرات التجميل، واقيات الشمس، وفي أنماط الحياة المختلفة، بسبب النطاق الواسع من التطبيقات وتعرضنا اليومي لهذه الجسيمات النانوية ونقص المعلومات عن صحة الحيوان والأنسان ، صُممت هذه الدراسة للكشف عن الآثار التي تعتمد على الجرعة والوقت من TiO2-NPs على وظائف الغدة الدرقية والكلى في ذكور الجرذان. لهذا الغرض تم استخدام 54 ذكر من الجرذان البيض وتم تصنيفها الى ثلاثة مجاميع رئيسية ( 3,2,1) كل مجموعه تتضمن 18 جرذ عوملت بثلاث فترات زمنية مختلفة (1 ,2 ,4) أسابيع على التوالي. وتم تقسيم هذه المجاميع الى ثلاث مجاميع فرعية كل منها تتضمن ست حيوانات تمت معاملتها على النحو التالي : (1) سيطرة , المجموعة (2 ,3) حقنت بالتجويف البروتوني بجرعات متزايدة من دقائق التيتانيوم النانوية (50 ,200) ملغ / كغم على التوالي. , في نهاية التجربة شرحت الجرذان وتم حساب وزن الغدة ووزن الكلى اليمنى واليسرى . النتائج اظهرت انخفاض معنوي عالي (p≤ 0.01) في وزن الغدة الدرقية وارتفاع معنوي عالي (p≤ 0.01) في وزن الكلى وفي مستوى هرمون TSH ويوريا الدم والكرياتين ومعدل البروتين الكلي , بينما انخفاض معنوي عالي في مستويات هرمون T3 و T4 المعاملة بجرعات مختلفة من 50- 200 ملغم / كغم TiO2في جميع الفترات الزمنية (1،2،4) اسابيع . توضح نتائج الدراسة الحالية انخفاضًا كبيرًا في مستوى مصل T4 و T3 مع التعرض لـ TiO2 NPS الذي يعطل وظيفة الغدة الدرقية ، بينما يرفع TiO2 NPS مستوى اليوريا والبروتين الكلي والكرياتينين. يمكن أن يكون هذا مرتبطًا بالجرعة العالية من TiO2-NPs ومدة الدراسة ، مما تسبب في تنكس ونخر خلايا الكلى وتلف في الحويصلات مما أدى إلى منع الإفراز الذي رفع مستويات اليوريا في الدم ، كما أدى إلى مستويات عالية من الكرياتينين والبروتين الكلي في المصل بسبب الخلل الذي حدث في وظائف الكلى.

The effect of Titanium Dioxide Nanoparticles on microhardness and SEM-EDS analysis of glass ionomer cement and amalgomer

Background: The aim of this study was to examine the effect of the addition of titanium dioxide (TiO2) nanoparticles on elemental composition and micro hardness of a conventional glass-ionomer and an amalgomer.Methods: A conventional glass ionomer cement (GICs) and an amalgomer were used in this study. Seventeen samples were prepared from each material using teflon molds (8 x 2) and determined as the control group. Each material was then blended with 3 % (w/w) TiO2 nanoparticles (anatase phase, 17 nm particle size) and seventeen samples were prepared to form experimental groups. Characterization of TiO2 nanoparticles, surface morphology evaluation and elemental composition analysis of the specimens were performed by Scanning Electron Microscope (SEM) and Energy Distribution Spectrometry (SEM-EDS). Specimens were submitted to the Vickers micro hardness test for 10 seconds at a load of 100gf. Data were analyzed with Shapiro-Wilk, Kruskal-Wallis and Bonferroni post-hoc tests (p=0.05).Results: EDS mapping showed the presence of elements typical for (GICs) in the composition of the control and experimental groups and a high proportion of titanium in the composition of experimental groups. Micro hardness data showed a small insignificant increase for the experimental groups compared with the control groups (p>0.05). While the highest mean microhardness value was recorded in Amalgomer (experimental) (84.34±4.33), Ionofil (control) exhibited the lowest mean micro hardness value (58.62±6.90).Conclusion: Within the limitations of this study, it can be concluded that the addition of 3% Ti02 nanoparticles improves the surface microhardness of the tested materials, although statistically insignificant, compared to unmodified GICs and amalgomer.

The effect of titanium dioxide nanoparticles on the relative expression of catalase, P450, SOD, diTDS and WRKY genes of Vitex agnus-castus L.

Each environmental factor is able to change the way genes are expressed. Application of nanoparticles also affects the expression of different genes in plants. The aim of this study was to investigate the effect of three different concentration of titanium dioxide nanoparticles, TiO2 (zero, 200 and 800 micrograms per milliliter) on the relative expression of catalase, P450, SOD, diTDS and WRKY genes in Vitex plant leaf tissue using qRT- PCR. Plant cultivation was carried out in 2018 in the greenhouse of Islamic Azad University of Mashhad. The experiment was arranged as completely random design with 5 replications. XRD measurements showed that applied TiO2 nanoparticles were in the form of anatase. Statistical analysis of gene expression in treated leaves of Vitex plant with TiO2 nanoparticles showed that this nanoparticle significantly affected the expression of catalase, P450, SOD, diTPS and WRKY genes. A concentration of 800 micrograms per milliliter of TiO2 nanoparticle increased the expression of catalase, P450, SOD and WRKY genes and decreased the expression of diTPS gene. In contrast, concentrations of 200 micrograms per milliliter only increased the expression of catalase and WRKY genes. The expression of the diTPS gene under treatments of 200 and 800 micrograms per liter of TiO2, compared with control, decreased by 2.1 and 0.46, respectively. Overall, the nanoparticle was able to influence the expression of genes in the biosynthetic pathway of terpenoids, as well as the plant's antioxidant enzymes, depending on the concentration of nanoparticles.

Potential toxic effects of titanium dioxide nanoparticles and carbon nanotubes on land snail Helix aspersa: use of oxidative stress as a reliable biomarker for ecotoxicology assessment

Potential toxic effects of titanium dioxide nanoparticles and carbon nanotubes on land snail Helix aspersa: use of oxidative stress as a reliable biomarker for ecotoxicology assessment

Inductive effect of titanium dioxide nanoparticles on the anticancer compounds production and expression of rosmarinic acid biosynthesis genes in Dracocephalum kotschyi transformed roots

Methoxylated flavonoids, mainly xanthomicrol and cirsimaritin that can be extracted from Dracocephalum kotschyi Boiss, have anticancer, antispasmodic and antiplatelet effects. The production of these valuable pharmaceutical compounds is one of the major goals of biotechnology studies. In this work, induced transformed roots were influenced by various concentrations of titanium dioxide nanoparticles (TiO2 NPs) at 24 or 48 h exposure time. The effects of TiO2 NPs were assessed on growth rate, activity of antioxidant enzymes, total phenol and flavonoid content (TPC and TFC) and rosmarinic acid (RA) and some flavonoids accumulation. The gene expression level of phenylalanine ammonia-lyase (pal) and rosmarinic acid synthase (ras) genes were assessed by real time PCR analysis. The transformed roots biomass was substantially increased in elicited roots in comparison with the control. The TPC, TFC and antioxidant enzymes activitywere affected by TiO2 NPs concentration and exposure time. Valuable flavonoids with anticancer characteristics along with xanthomicrol, cirsimaritin and isokaempferide exhibited an increase (70, 34.28 and 7.81-fold, respectively) versus the control. The maximum content of RA (530.5 μg g−1 FW), which was 4.30 times as great as that of control was detected in samples treated with TiO2 NPs (50 mg L−1) 24 h after elicitation. Real-time PCR analysis revealed a considerable increase in pal and ras expression rate engaged by TiO2 NPs levels and exposure time. Overall D. kotschyi transformed roots elicitation by TiO2 NPs led to a massive increment in the production of valuable anticancer flavonoids such as xanthomicrol, cirsimaritin and RA as polyphenol.

Ecotoxicological effects of dietary titanium dioxide nanoparticles on metabolic and biochemical parameters of model organism Galleria mellonella (Lepidoptera: Pyralidae)

Nanoparticles (NPs) are now being used in many industrial activities, such as mining, paint and glass industries. The frequent industrial use of NPs contributes to environmental pollution and may cause cellular and oxidative damage in native organisms. In this study, the toxic effects of titanium dioxide nanoparticles (TiO2 NPs) were investigated using Galleria mellonella larvae as a model insect species. Alterations in cell damage indicators, such as alanine transferase, aspartate transferase, lactate dehydrogenase, non-enzymatic antioxidants and biochemical parameters, were determined in the hemolymph of G. mellonella larvae exposed to TiO2 NPs at different concentrations (5, 50, 250 and 1250 μg/mL) in their diets. TiO2 NPs caused concentration-dependent cellular damage in the hemolymph of G. mellonella larvae and increased the levels of the non-enzymatic antioxidants uric acid and bilirubin. In addition, total protein in hemolymph significantly decreased at the highest concentration (1250 μg/mL) of TiO2 NPs. Level of the urea increased at the highest concentration (1250 μg/mL) of TiO2 NPs, whereas the amount of glucose was not affected. These findings demonstrated that TiO2 NPs caused concentration-dependent toxic effects on G. mellonella larvae.

Nano-TiO2 aggravates bioaccumulation and developmental neurotoxicity of triphenyl phosphate in zebrafish larvae

This study explored the combined effects of titanium dioxide nanoparticles (nano-TiO2) and triphenyl phosphate (TPhP) on the neurodevelopment of zebrafish larvae as well as the underlying mechanisms. With this regard, zebrafish embryos were exposed to nano-TiO2 of 100 μg·L−1, TPhP of 0, 8, 24, 72, and 144 μg·L−1, or their combinations until 120 h post-fertilization (hpf). Results indicated 100 μg·L−1 nano-TiO2 alone to be nontoxic to zebrafish larvae. However, obvious developmental toxicity manifested as inhibition of surviving rate, heart rate and body length as well as increased malformation was observed in the higher concentrations of TPhP (72 and 144 μg·L−1) alone and the co-exposure groups. Additionally, results suggested that nano-TiO2 significantly enhanced the bioaccumulation of TPhP in zebtafish larvae, and thus aggravated the abnormities of spontaneous movement and swimming behavior in zebrafish larvae induced by TPhP. Nano-TiO2 also exacerbated the TPhP-induced inhibition of the axonal growth on the secondary motor neuron, and aggravated the TPhP-induced decrease on expressions of neuron-specific green fluorescent protein (GFP) and neuronal marker genes (ngn1 and elavl3). Further, the content of neurotransmitter serotonin was not altered by TPhP alone exposure, but was decreased significantly in the co-exposure group of 144 μg·L−1 TPhP and nano-TiO2. Our data indicated that nano-TiO2 might aggravate the neuron abnormities and serotonin system dysfunction by enhancing the TPhP accumulation, leading to exacerbated abnormal locomotors in zebrafish larvae.

Effect of titanium dioxide nanoparticles on DNA methylation of human peripheral blood mononuclear cells.

The aim of the current study was to investigate the effect of well-characterized TiO2 nanoparticles on DNA methylation of peripheral blood mononuclear cells (PBMCs) in vitro. Maximum non-toxic concentration of nanoparticles for PBMCs was determined by MTT assay. The effect of TiO2 nanoparticles at concentrations of 25-100μg/ml on DNA methylation of PBMCs was investigated by measuring the %5-mC alterations through an ELISA assay. The physicochemical analysis showed that the TiO2 nanoparticles were crystalline, pure and in the anatase phase. Peaks related to Ti-O tensile vibrations were observed in the range of 1510cm-1. The size of nanoparticles was in the range of 39-74nm with an average hydrodynamic diameter of 43.82nm. According to the results of the MTT test, 100μg/ml was found to be maximum non-toxic concentration. The %5-mC in treated PBMCs revealed that TiO2 nanoparticles could lead to DNA hypomethylation in PBMCs. The %5-mC difference compared with the negative control was found to be 2.07 ± 1.02% (P=0.03). The difference of %5-mC between the 25 and 100μg/ml concentration of nanoparticles was statistically significant (P=0.02). The results of the current study show that the TiO2 nanoparticles cause DNA hypomethylation in PBMCs in a dose-response manner. Therefore, it is recommended to evaluate the effects of cytotoxicity and epigenotoxicity of commonly used nanoparticles before their use.