Compendium of the most significant studies with reference to properties, intake, effects.

Grande F, Tucci P. Titanium Dioxide Nanoparticles: a Risk for Human Health? Mini Rev Med Chem. 2016;16(9):762-9. doi: 10.2174/1389557516666160321114341.

Abstract. Titanium dioxide (TiO₂) is a natural oxide of the element titanium with low toxicity, and negligible biological effects. The classification as bio-inert material has given the possibility to normal-sized (>100 nm) titanium dioxide particles (TiO₂-NPs) to be extensively used in food products and as ingredients in a wide range of pharmaceutical products and cosmetics, such as sunscreens and toothpastes. Therefore, human exposure may occur through ingestion and dermal penetration, or through inhalation route, during both the manufacturing process and use.

Fuster E, Candela H, Estévez J, Vilanova E, Sogorb MA. Titanium Dioxide, but Not Zinc Oxide, Nanoparticles Cause Severe Transcriptomic Alterations in T98G Human Glioblastoma Cells. Int J Mol Sci. 2021 Feb 19;22(4):2084. doi: 10.3390/ijms22042084.

Abstract. Alterations to the transcriptome suggests that exposure to titanium dioxide nanoparticles might, potentially, compromise the integrity of the blood brain barrier integrity and cause neuroinflammation.

Murugadoss S, Brassinne F, Sebaihi N, Petry J, Cokic SM, Van Landuyt KL, Godderis L, Mast J, Lison D, Hoet PH, van den Brule S. Agglomeration of titanium dioxide nanoparticles increases toxicological responses in vitro and in vivo. Part Fibre Toxicol. 2020 Feb 26;17(1):10. doi: 10.1186/s12989-020-00341-7.

Abstract. ...We tested two TiO2 NPs with different primary sizes (17 and 117 nm) and prepared ad-hoc suspensions composed of small or large agglomerates with similar dispersion medium composition....Mainly, we observed that large agglomerates of 117 nm TiO2 induced higher pulmonary responses in aspirated mice and blood DNA damage in gavaged mice compared to small agglomerates....

Grasso A, Ferrante M, Zuccarello P, Filippini T, Arena G, Fiore M, Cristaldi A, Conti GO, Copat C. Chemical Characterization and Quantification of Titanium Dioxide Nanoparticles (TiO2-NPs) in Seafood by Single-Particle ICP-MS: Assessment of Dietary Exposure. Int J Environ Res Public Health. 2020 Dec 20;17(24):9547. doi: 10.3390/ijerph17249547. 

Abstract. Since the aquatic environment is highly sensitive to contamination by TiO2-NPs, this work aimed to give a preliminary assessment of the contamination of packaged seafood, where the food additive TiO2 (E171) is not to be intentionally added.

Haynes VN, Ward JE, Russell BJ, Agrios AG. Photocatalytic effects of titanium dioxide nanoparticles on aquatic organisms-Current knowledge and suggestions for future research. Aquat Toxicol. 2017 Apr;185:138-148. doi: 10.1016/j.aquatox.2017.02.012.

Abstract. The purpose of this review is to summarize the current knowledge of the photocatalytic effects of TiO2 nanoparticles on aquatic organisms, discuss the limitations of these studies, and outline environmentally-relevant factors that need to be considered in future experiments.

Wu J, Bosker T, Vijver MG, Peijnenburg WJGM. Trophic Transfer and Toxicity of (Mixtures of) Ag and TiO₂ Nanoparticles in the Lettuce-Terrestrial Snail Food Chain. Environ Sci Technol. 2021 Nov 29. doi: 10.1021/acs.est.1c05006.

Abstract. The increasing application of biosolids and agrochemicals containing silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiO₂NPs) results in their inevitable accumulation in soil, with unknown implications along terrestrial food chains.

Jimeno-Romero A, Gwinner F, Müller M, Mariussen E, Soto M, Kohl Y. Sea Bass Primary Cultures versus RTgill-W1 Cell Line: Influence of Cell Model on the Sensitivity to Nanoparticles. Nanomaterials (Basel). 2021 Nov 20;11(11):3136. doi: 10.3390/nano11113136.

Abstract. Data shows that more variables significantly influenced the outcome of toxicity tests when the primary cultures were exposed to the different nanoparticles. Toxicity tests performed in RTgill-W1 were influenced only by exposure time and nanoparticle concentration. The whole data set was integrated in a biological response index to show the overall impact of nanoparticle exposures.

Boland S, Hussain S, Baeza-Squiban A. Carbon black and titanium dioxide nanoparticles induce distinct molecular mechanisms of toxicity. Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2014 Nov-Dec;6(6):641-52. doi: 10.1002/wnan.1302.

Abstract. In the present manuscript we discuss the similarities and differences in molecular pathways of toxicity after carbon black (CB) and titanium dioxide (TiO₂) nanoparticle exposures and identify the main toxicity mechanisms induced by these two nanoparticles which may also be indicative for the mode of action of other insoluble nanomaterials.

Onishchenko GE, Erokhina MV, Abramchuk SS, Shaitan KV, Raspopov RV, Smirnova VV, Vasilevskaya LS, Gmoshinski IV, Kirpichnikov MP, Tutelyan VA. Effects of titanium dioxide nanoparticles on small intestinal mucosa in rats. Bull Exp Biol Med. 2012 Dec;154(2):265-70. doi: 10.1007/s10517-012-1928-9.

Abstract. Penetration of titanium dioxide nanoparticles into enterocytes after their administration into isolated loop of rat small intestine was shown in vivo by transmission electron microscopy.

Swidwińska-Gajewska AM, Czerczak S.  Titanium dioxide nanoparticles: occupational exposure limits. Med Pr. 2014;65(3):407-18.

Abstract.  Titanium dioxide nanoparticles are increasingly applied in cosmetics, textiles and plastics as the ultraviolet light blocker. This contributes to a growing occupational exposure to TiO₂ nanoparticles. Nanoparticles are potentially responsible for the most adverse effects of titanium dioxide.

Yamashita K, Yoshioka Y, Higashisaka K, Mimura K, Morishita Y, Nozaki M, Yoshida T, Ogura T, Nabeshi H, Nagano K, Abe Y, Kamada H, Monobe Y, Imazawa T, Aoshima H, Shishido K, Kawai Y, Mayumi T, Tsunoda S, Itoh N, Yoshikawa T, Yanagihara I, Saito S, Tsutsumi Y. Silica and titanium dioxide nanoparticles cause pregnancy complications in mice. Nat Nanotechnol. 2011 May;6(5):321-8. doi: 10.1038/nnano.2011.41.

Abstract. The increasing use of nanomaterials has raised concerns about their potential risks to human health. Recent studies have shown that nanoparticles can cross the placenta barrier in pregnant mice and cause neurotoxicity in their offspring, but a more detailed understanding of the effects of nanoparticles on pregnant animals remains elusive. Here, we show that silica and titanium dioxide nanoparticles with diameters of 70 nm and 35 nm, respectively, can cause pregnancy complications