TiO(2) nanoparticles and bulk material stimulate human peripheral blood mononuclear cells

Ti-containing NPs in raw water and their removal with conventional treatments in four water treatment plants in Taiwan

The ingestion of Ti-containing nanoparticles from drinking water has emerged as a concern in recent years. This study therefore aimed to characterize Ti-containing nanoparticles in water samples collected from four water treatment plants in Taiwan and to explore the challenges associated with measuring them at low levels using single particle-inductively coupled plasma mass spectrometry. Additionally, the study sought to identify the most effective processes for the removal of Ti-containing nanoparticles. For each water treatment plant, two water samples were collected from raw water, sedimentation effluent, filtration effluent, and finished water, respectively. Results revealed that Ti-containing nanoparticles in raw water, with levels at 8.69 μg/L and 296.8 × 103 particles/L, were removed by approximately 35% and 98%, respectively, in terms of mass concentration and particle number concentration, primarily through flocculation and sedimentation processes. The largest most frequent nanoparticle size in raw water (112.0 ± 2.8 nm) was effectively reduced to 62.0 ± 0.7 nm in finished water, while nanoparticles in the size range of 50-70 nm showed limited changes. Anthracite was identified as a necessary component in the filter beds to further improve removal efficiency at the filtration unit. Moreover, the most frequent sizes of Ti-containing nanoparticles were found to be influenced by salinity. Insights into the challenges associated with measuring low-level Ti-containing nanoparticles in aqueous samples provide valuable information for future research and management of water treatment processes, thereby safeguarding human health.

M. N. Mydin RB, Widera D, Noordin SS, Harun NH, Wan Eddis Effendy WN, Hazan R, Sreekantan S. Double-edged sword of biofouling potentials associated with haemocompatibility behaviour: titania nanotube arrays for medical implant surface technology

Background

Medical implant failures are frequently associated with limitations of the surface technology that lead to biofouling and haemocompatibility issues. Titania nanotube array technology could provide a solution for this existing limitation. The present study describes the biofouling potential using the simulated body fluid model according to ISO 23317-2007 and haemocompatibility profiles according to ISO 10993-4 guidelines. Further haemocompatibility profiles were also assessed by evaluating full blood count, coagulation assays, haemolytic rate, whole blood clotting factor, platelet profiles, and FESEM characterization.

Result

Titania nanotube array nanosurface was found to present with better apatite biofouling and hydrophilic potential compared to bare titanium foil. Furthermore, good compatibility behaviour was observed based on the haemocompatibility profiles where no signs of thrombogenesis and haemolysis risks were observed. Titania nanotube array reduced fibrinogen adsorption, red blood cell and platelet adhesion and activation, which could be associated with detrimental biofouling properties.

Conclusion

Titania nanotube array could possess a double-edged sword of biofouling potentials that resist detrimental biofouling properties associated with thrombogenesis and haemolysis risk. It also provides better apatite biofouling potential for improved tissue and osseointegration activities. Knowledge from this study provides a better understanding of medical implant surface technology.

Graphical Abstract

Essential Oil Nanoemulsion Hydrogel with Anti-Biofilm Activity for the Treatment of Infected Wounds

The formation of a bacterial biofilm on an infected wound can impede drug penetration and greatly thwart the healing process. Thus, it is essential to develop a wound dressing that can inhibit the growth of and remove biofilms, facilitating the healing of infected wounds. In this study, optimized eucalyptus essential oil nanoemulsions (EEO NEs) were prepared from eucalyptus essential oil, Tween 80, anhydrous ethanol, and water. Afterward, they were combined with a hydrogel matrix physically cross-linked with Carbomer 940 (CBM) and carboxymethyl chitosan (CMC) to prepare eucalyptus essential oil nanoemulsion hydrogels (CBM/CMC/EEO NE). The physical-chemical properties, in vitro bacterial inhibition, and biocompatibility of EEO NE and CBM/CMC/EEO NE were extensively investigated and the infected wound models were proposed to validate the in vivo therapeutic efficacy of CBM/CMC/EEO NE. The results showed that the average particle size of EEO NE was 15.34 ± 3.77 nm with PDI ˂ 0.2, the minimum inhibitory concentration (MIC) of EEO NE was 15 mg/mL, and the minimum bactericidal concentration (MBC) against S. aureus was 25 mg/mL. The inhibition and clearance of EEO NE against S. aureus biofilm at 2×MIC concentrations were 77.530 ± 7.292% and 60.700 ± 3.341%, respectively, demonstrating high anti-biofilm activity in vitro. CBM/CMC/EEO NE exhibited good rheology, water retention, porosity, water vapor permeability, and biocompatibility, meeting the requirements for trauma dressings. In vivo experiments revealed that CBM/CMC/EEO NE effectively promoted wound healing, reduced the bacterial load of wounds, and accelerated the recovery of epidermal and dermal tissue cells. Moreover, CBM/CMC/EEO NE significantly down-regulated the expression of two inflammatory factors, IL-6 and TNF-α, and up-regulated three growth-promoting factors, TGF-β1, VEGF, and EGF. Thus, the CBM/CMC/EEO NE hydrogel effectively treated wounds infected with S. aureus, enhancing the healing process. It is expected to be a new clinical alternative for healing infected wounds in the future.

The Stability and Anti-Angiogenic Properties of Titanium Dioxide Nanoparticles (TiO2NPs) Using Caco-2 Cells

Titanium dioxide nanoparticles (TiO₂NPs) are found in a wide range of products such as sunscreen, paints, toothpaste and cosmetics due to their white pigment and high refractive index. These wide-ranging applications could result in direct or indirect exposure of these NPs to humans and the environment. Accordingly, conflicting levels of toxicity has been associated with these NPs. Therefore, the risk associated with these reports and for TiO₂NPs produced using varying methodologies should be measured. This study aimed to investigate the effects of various media on TiO₂NP properties (hydrodynamic size and zeta potential) and the effects of TiO₂NP exposure on human colorectal adenocarcinoma (Caco-2) epithelial cell viability, inflammatory and cell stress biomarkers and angiogenesis proteome profiles. The NPs increased in size over time in the various media, while zeta potentials were stable. TiO₂NPs also induced cell stress biomarkers, which could be attributed to the NPs not being cytotoxic. Consequently, TiO₂NP exposure had no effects on the level of inflammatory biomarkers produced by Caco-2. TiO₂NPs expressed some anti-angiogenic properties when exposed to the no-observed-adverse-effect level and requires further in-depth investigation.

Industrial-relevant TiO2 types do not promote cytotoxicity in the A549 or TK6 cell lines regardless of cell specific interaction

Due to the expansive application of TiO₂ and its variance in physico-chemical characteristics, the toxicological profile of TiO₂, in all its various forms, requires evaluation. This study aimed to assess the hazard of five TiO₂ particle-types in relation to their cytotoxic profile correlated to their cellular interaction, specifically in human lymphoblast (TK6) and type-II alveolar epithelial (A549) cells. Treatment with the test materials was undertaken at a concentration range of 1-100 μg/cm² over 24 and 72 h exposure. TiO₂ interaction with both cell types was visualised by transmission electron microscopy, supported by energy-dispersive X-ray. None of the TiO₂ materials tested promoted cytotoxicity in either cell type over the concentration and time range studied. All materials were observed to interact with the A549 cells and were further noted to be internalised following 24 h exposure. In contrast, only the pigmentary rutile was internalised by TK6 lymphoblasts after 24 h exposure. Where uptake was observed there was no evidence, as determined by 2D microscopy techniques, of particle localisation within the nucleus of either cell type. This study indicates that industrially relevant TiO₂ particles demonstrate cell interactions that are cell-type dependent and do not induce cytotoxicity at the applied dose range.

Characterization of Ti-containing nanoparticles in the aquatic environment of the Tamsuei River Basin in northern Taiwan

Titanium dioxide (TiO₂) is commonly contained in many commercial products and there are concerns about its release into the aquatic environment after use. This study was designed to characterize the distribution of Ti-containing nanoparticulates (NPs) in the water of the Tamsuei River Basin in northern Taiwan. Water samples were collected from the upstream, mid-stream, and downstream areas of the Tamsuei River Basin and analyzed with single-particle ICPMS to profile the Ti-containing NPs in terms of mass concentration, number concentration and particulate size. The lowest mass concentration of Ti-containing NPs, 1.04 ± 0.04 μg/L, was found in the upstream water samples, while the highest mass concentration, 31.7 ± 0.6 μg/L, was observed in downstream samples; there was an increasing trend from upstream to downstream. The highest particulate number concentration, 479 ± 163 × 10³/mL, was observed for the downstream samples, but the lowest concentration, 45.4 ± 5.6 × 10³/mL, was found in the mid-stream water samples taken from Site C. Moreover, the average mode values for particulate sizes were approximately 50 nm for all samples, although a relatively larger average mode value of 62 ± 5.7 nm was observed in the mid-stream samples from Site A. Increasing mass concentrations and particulate number concentrations from upstream to downstream implied that these NPs might have originally resulted from anthropogenic activities involving the use of TiO₂ NPs-containing products. Surprisingly, however, the lowest number concentrations for Ti-containing NPs in the mid-stream samples can probably be attributed to the fact that the corresponding sampling sites were located in the water preservation zone, which exhibits a particle-settling effect. Additionally, the sizes of Ti-containing NPs in downstream samples were not significantly larger than those in the upstream and mid-stream samples, as expected, which was probably due to the steric effects resulting from the presence of large amounts of macromolecule polymers in aquatic environments.

The impact of TiO2 nanoparticle exposure on transmembrane cholesterol transport and enhanced bacterial infectivity in HeLa cells

We have previously shown that exposure to TiO₂ nanoparticles (NPs) reduces the resistance of HeLa cells to bacterial infection. Here we demonstrate that the increased infectivity is associated with enhanced asymmetry in the cholesterol distribution. We applied a live cell imaging method which uses tunable orthogonal cholesterol sensors to visualize and quantify in-situ cholesterol distribution between the two leaflets of the plasma membrane (PM). In the control culture, we found marked transbilayer asymmetry of cholesterol, with the concentration in the outer plasma membrane (OPM) being 13 ± 2-fold higher than that in the inner plasma membrane (IPM). Exposure of the culture to 0.1 mg/mL of rutile TiO₂ NPs increased the asymmetry such that the concentration in the OPM was 51 ± 10 times higher, while the total cholesterol content increased only 21 ± 2%. This change in cholesterol gradient may explain the increase in bacterial infectivity in HeLa cells exposed to TiO₂ NPs since many pathogens, including Staphylococcus aureus used in the present study, require cholesterol for proper membrane attachment and virulence. RT-PCR indicated that exposure to TiO₂ was responsible for upregulation of the ABCA1 and ABCG1 mRNAs, which are responsible for the production of the cholesterol transporter proteins that facilitate cholesterol transport across cellular membranes. This was confirmed by the observation of an overall decrease in bacterial infection in ABCA1 knockout or methyl-β-cyclodextrin-treated HeLa cells, as regardless of TiO₂ NP exposure. Hence rather than preventing bacterial infection, TiO₂ nanoparticles upregulate genes associated with membrane cholesterol production and distribution, hence increasing infectivity. STATEMENT OF SIGNIFICANCE: A great deal of work has been done regarding the toxicology of the particles, especially focusing on detrimental outcomes associated with reactive oxygen species (ROS) production. In this paper we show unambiguously a very surprising result, namely the ability of these particles to enhance bacterial infection even at very small exposure levels, where none of the deleterious effects of ROS products can yet be detected. Using a new imaging technique, we are able to demonstrate, in operando, the effect of the particles on cholesterol generation and distribution in live HeLa cells. This paper also represents the first in a series where we explore other consequences of increased membrane cholesterol, due to particle exposure, which are known to have multiple other consequences on human tissue function and development.

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.

Molecular photoprotection of human keratinocytes in vitro by the naturally occurring mycosporine-like amino acid palythine

Background

Solar ultraviolet radiation (UVR) induces molecular and genetic changes in the skin, which result in skin cancer, photoageing and photosensitivity disorders. The use of sunscreens is advocated to prevent such photodamage; however, most formulations contain organic and inorganic UVR filters that are nonbiodegradable and can damage fragile marine ecosystems. Mycosporine‐like amino acids (MAAs) are natural UVR‐absorbing compounds that have evolved in marine species for protection against chronic UVR exposure in shallow‐water habitats.

Objectives

To determine if palythine, a photostable model MAA, could offer protection against a range of UVR‐induced damage biomarkers that are important in skin cancer and photoageing.

Methods

HaCaT human keratinocytes were used to assess the photoprotective potential of palythine using a number of end points including cell viability, DNA damage (nonspecific, cyclobutane pyrimidine dimers and oxidatively generated damage), gene expression changes (linked to inflammation, photoageing and oxidative stress) and oxidative stress. The antioxidant mechanism was investigated using chemical quenching and Nrf2 pathway activation assays.

Results

Palythine offered statistically significant protection (P < 0·005) against all end points tested even at extremely low concentrations (0·3% w/v). Additionally, palythine was found to be a potent antioxidant, reducing oxidatively generated stress, even when added after exposure.

Conclusions

Palythine is an extremely effective multifunctional photoprotective molecule in vitro that has potential to be developed as a natural and biocompatible alternative to currently approved UVR filters.

What's already known about this topic?

Mycosporine‐like amino acids (MAAs) are photoprotective molecules found in marine organisms but there are few data on their ability to protect skin cells from the adverse effects of solar ultraviolet radiation (UVR).

The European Chemicals Agency (ECHA) is concerned about the potential adverse health and ecotoxic effects of eight of 16 commonly used sunscreen filters in Europe. The Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme has expressed similar concerns.

What does this study add?

Palythine, an MAA extracted from an edible seaweed, affords photoprotection against a wide range of adverse effects in HaCaT keratinocytes exposed to solar simulating and ultraviolet A radiation. Of note is protection against two types of DNA photolesions; cyclobutane pyrimidine dimers and 8‐oxo‐7,8‐dihydroguanine.

Palythine is also a potent antioxidant that offers protection even when added after UVR exposure.

What is the translational message?

MAAs should be considered for development as natural biocompatible sunscreens that may address the concerns of the ECHA and EEAP.

Linked Comment: https://doi.org/10.1111/bjd.16598.

https://goo.gl/Uqv3dl

Nonactivated titanium-dioxide nanoparticles promote the growth of Chlamydia trachomatis and decrease the antimicrobial activity of silver nanoparticles

AIMS

Chlamydia trachomatis and herpes simplex virus (HSV) are the most prevalent bacterial and viral sexually transmitted infections. Due to the chronic nature of their infections, they are able to interact with titanium-dioxide (TiO₂ ) nanoparticles (NPs) applied as food additives or drug delivery vehicles. The aim of this study was to describe the interactions of these two prevalent pathogens with the TiO₂ NPs.

METHODS AND RESULTS

Chlamydia trachomatis and HSV-2 were treated with nonactivated TiO₂ NPs, silver NPs and silver decorated TiO₂ NPs before infection of HeLa and Vero cells. Their intracellular growth was monitored by quantitative PCR. Unexpectedly, the TiO₂ NPs (100 μg ml^-1 ) increased the growth of C. trachomatis by approximately fourfold, while the HSV-2 replication was not affected. Addition of TiO₂ to silver NPs decreased their antimicrobial activity against C. trachomatis up to 27·92-fold.

CONCLUSION

In summary, nonactivated TiO₂ NPs could increase the replication of C. trachomatis and decrease the antimicrobial activity of silver NPs.

SIGNIFICANCE AND IMPACT OF THE STUDY

The food industry or drug delivery use of TiO₂ NPs could enhance the growth of certain intracellular pathogens and potentially worsen disease symptoms, a feature that should be further investigated.

Moving into advanced nanomaterials. Toxicity of rutile TiO2 nanoparticles immobilized in nanokaolin nanocomposites on HepG2 cell line

Immobilization of nanoparticles on inorganic supports has been recently developed, resulting in the creation of nanocomposites. Concerning titanium dioxide nanoparticles (TiO₂ NPs¹), these have already been developed in conjugation with clays, but so far there are no available toxicological studies on these nanocomposites. The present work intended to evaluate the hepatic toxicity of nanocomposites (C-TiO₂²), constituted by rutile TiO₂ NPs immobilized in nanokaolin (NK³) clay, and its individual components. These nanomaterials were analysed by means of FE-SEM⁴ and DLS⁵ analysis for physicochemical characterization. HepG2 cells were exposed to rutile TiO₂ NPs, NK clay and C-TiO₂ nanocomposite, in the presence and absence of serum for different exposure periods. Possible interferences with the methodological procedures were determined for MTT,⁶ neutral red uptake, alamar blue (AB), LDH,⁷ and comet assays, for all studied nanomaterials. Results showed that MTT, AB and alkaline comet assay were suitable for toxicity analysis of the present materials after slight modifications to the protocol. Significant decreases in cell viability were observed after exposure to all studied nanomaterials. Furthermore, an increase in HepG2 DNA damage was observed after shorter periods of exposure in the absence of serum proteins and longer periods of exposure in their presence. Although the immobilization of nanoparticles in micron-sized supports could, in theory, decrease the toxicity of single nanoparticles, the selection of a suitable support is essential. The present results suggest that NK clay is not the appropriate substrate to decrease TiO₂ NPs toxicity. Therefore, for future studies, it is critical to select a more appropriate substrate for the immobilization of TiO₂ NPs.

Cytotoxic and inflammatory responses of TiO2 nanoparticles on human peripheral blood mononuclear cells

Titanium dioxide nanoparticles (TiO2 -NPs) have been widely used in many applications. Owing to their nanoscale size, interactions between cells and NPs have been expansively investigated. With the health concerns raised regarding the adverse effects of these interactions, closer examination of whether TiO2 -NPs can induce toxicity towards human cells is greatly needed. Therefore, in this study, we investigated the cytotoxicity of TiO2 -NPs towards human blood cells (peripheral blood mononuclear cells [PBMCs]) in serum-free medium, for which there is little information regarding the cytotoxic effects of TiO2 -NPs. Our results provide evidence that PBMCs treated with TiO2 -NPs (at concentrations ≥25 μg ml(-1) ) for 24 h significantly reduced cell viability and significantly increased production of toxic mediators such as reactive oxygen species and inflammatory response cytokines such as interleukin-6 and tumor necrosis factor-α (P < 0.05). Cell apoptosis induction also occurred at these concentrations. Significant expressions of cyclooxygenase-2 and interleukin-1β were also observed in PBMCs treated with TiO2 -NPs at concentrations ≥125 μg ml(-1) . Our data presented here clearly indicate that the concentration of TiO2 -NPs (at size ~26.4 ± 1.2 nm) applied to human blood cells has a strong impact on cytotoxic induction. Copyright © 2016 John Wiley & Sons, Ltd.

Exposure to TiO2 nanoparticles increases Staphylococcus aureus infection of HeLa cells

Background

Titanium dioxide (TiO₂) is one of the most common nanoparticles found in industry ranging from food additives to energy generation. Approximately four million tons of TiO₂ particles are produced worldwide each year with approximately 3000 tons being produced in nanoparticulate form, hence exposure to these particles is almost certain.

Results

Even though TiO₂ is also used as an anti-bacterial agent in combination with UV, we have found that, in the absence of UV, exposure of HeLa cells to TiO₂ nanoparticles significantly increased their risk of bacterial invasion. HeLa cells cultured with 0.1 mg/ml rutile and anatase TiO₂ nanoparticles for 24 h prior to exposure to bacteria had 350 and 250 % respectively more bacteria per cell. The increase was attributed to bacterial polysaccharides absorption on TiO₂ NPs, increased extracellular LDH, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO₂ particles ingested 40 % fewer bacteria, further increasing the risk of infection.

Conclusions

In combination, these two factors raise serious concerns regarding the impact of exposure to TiO₂ nanoparticles on the ability of organisms to resist bacterial infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0184-y) contains supplementary material, which is available to authorized users.

Ionizing radiation-engineered nanogels as insulin nanocarriers for the development of a new strategy for the treatment of Alzheimer's disease

A growing body of evidence shows the protective role of insulin in Alzheimer's disease (AD). A nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for Alzheimer's Disease (AD), is designed and synthetized. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation is chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility and hemocompatibility of the naked carrier is demonstrated. The insulin conjugated to the NG (NG-In) is protected by protease degradation and able to bind to insulin receptor (IR), as demonstrated by immunofluorescence measurements showing colocalization of NG-In(FITC) with IR. Moreover, after binding to the receptor, NG-In is able to trigger insulin signaling via AKT activation. Neuroprotection of NG-In against dysfunction induced by amyloid β (Aβ), a peptide mainly involved in AD, is verified. Finally, the potential of NG-In to be efficiently transported across the Blood Brain Barrier (BBB) is demonstrated. All together these results indicate that the synthesized NG-In is a suitable vehicle system for insulin deliver in biomedicine and a very promising tool to develop new therapies for neurodegenerative diseases.

Comparative cellular toxicity of titanium dioxide nanoparticles on human astrocyte and neuronal cells after acute and prolonged exposure

Although in the last few decades, titanium dioxide nanoparticles (TiO₂NPs) have attracted extensive interest due to their use in wide range of applications, their influences on human health are still quite uncertain and less known. Evidence exists indicating TiO₂NPs ability to enter the brain, thus representing a realistic risk factor for both chronic and accidental exposure with the consequent needs for more detailed investigation on CNS. A rapid and effective in vitro test strategy has been applied to determine the effects of TiO₂NPs anatase isoform, on human glial (D384) and neuronal (SH-SY5Y) cell lines. Toxicity was assessed at different levels: mitochondrial function (by MTT), membrane integrity and cell morphology (by calcein AM/PI staining) after acute exposure (4-24-48 h) at doses from 1.5 to 250 μg/ml as well as growth and cell proliferation (by clonogenic test) after prolonged exposure (7-10 days) at sub-toxic concentrations (from 0.05 to 31 μg/ml). The cytotoxic effects of TiO₂NPs were compared with those caused by TiO₂ bulk counterpart treatment. Acute TiO₂NP exposure produced (i) dose- and time-dependent alterations of the mitochondrial function on D384 and SH-SY5Y cells starting at 31 and 15 μg/ml doses, respectively, after 24h exposure. SH-SY5Y were slightly more sensitive than D384 cells; and (ii) cell membrane damage occurring at 125 μg/ml after 24h exposure in both cerebral cells. Comparatively, the effects of TiO₂ bulk were less pronounced than those induced by nanoparticles in both cerebral cell lines. Prolonged exposure indicated that the proliferative capacity (colony size) was compromised at the extremely low TiO₂NP doses namely 1.5 μg/ml and 0.1 μg/ml for D384 and SH-SY5Y, respectively; cell sensitivity was still higher for SH-SY5Y compared to D384. Colony number decrease (15%) was also evidenced at ≥0.2 μg/ml TiO₂NP dose. Whereas, TiO₂ bulk treatment affected cell morphology only. TiO₂ internalization in SH-SY5Y and D384 cells was appreciated using light microscopy. These findings indicated, that (i) human cerebral SH-SY5Y and D384 cell lines exposed to TiO₂NPs were affected not only after acute but even after prolonged exposure at particularly low doses (≥ 0.1 μg/ml), (ii) these in vitro critical doses were comparable to literature brain Ti levels detected in lab animal intranasally administered with TiO₂NP and associated to neurotoxic effects. In summary, the applied cell-based screening platform seems to provide effective means to initial evaluation of TiO₂NP toxicity on CNS.