Titanium dioxide nanoparticles: A review of current toxicological data

Particle and Fibre Toxicology (Impact Factor: 7.11). 04/2013; 10(1):15. DOI: 10.1186/1743-8977-10-15
Source: PubMed


Titanium dioxide (TiO2) nanoparticles (NPs) are manufactured worldwide in large quantities for use in a wide range of applications. TiO2 NPs possess different physicochemical properties compared to their fine particle (FP) analogs, which might alter their bioactivity. Most of the literature cited here has focused on the respiratory system, showing the importance of inhalation as the primary route for TiO2 NP exposure in the workplace. TiO2 NPs may translocate to systemic organs from the lung and gastrointestinal tract (GIT) although the rate of translocation appears low. There have also been studies focusing on other potential routes of human exposure. Oral exposure mainly occurs through food products containing TiO2 NP-additives. Most dermal exposure studies, whether in vivo or in vitro, report that TiO2 NPs do not penetrate the stratum corneum (SC). In the field of nanomedicine, intravenous injection can deliver TiO2 nanoparticulate carriers directly into the human body. Upon intravenous exposure, TiO2 NPs can induce pathological lesions of the liver, spleen, kidneys, and brain. We have also shown here that most of these effects may be due to the use of very high doses of TiO2 NPs. There is also an enormous lack of epidemiological data regarding TiO2 NPs in spite of its increased production and use. However, long-term inhalation studies in rats have reported lung tumors. This review summarizes the current knowledge on the toxicology of TiO2 NPs and points out areas where further information is needed.

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    • "Maiaugree et al. for instance reported substantial increase in photocurrent density in PEDOT:PSS–TiO 2 nanoparticle-based DSSC (Maiaugree et al. 2012). Inorganic TiO 2 nanoparticles are well known for their exceptional properties such as low toxicity, chemical stability in acidic and aqueous conditions and photosensitivity (Pottier et al. 2001; Shi et al. 2013; Takahashi et al. 2004). It has motivated us to improve the sensing performance of the photodetector by optically engineering the PEDOT:PSS buffer layer. "
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    ABSTRACT: The sensing parameters of previously reported PFO-DBT:MEH-PPV:PC71BM ternary blend based organic photodetector have been improved in the present study. Improvement has been successfully demonstrated by doping TiO2 nanoparticles in the PEDOT:PSS thin film. TiO2 nanoparticles of 50, 100 and 250 nm diameters have initially been dispersed in PEDOT:PSS and the resulting suspension has been spun coated on glass substrates and subjected to UV/vis and PL study. Thin film of PEDOT:PSS-TiO2 (100 nm) has shown maximum quenching in PL spectra, along with fairly good visible light absorption. For further studies, 5 wt. % TiO2 (100 nm) nanoparticles dispersion in PEDOT:PSS has been utilized for the fabrication of ITO/PEDOT:PSS-TiO2/PFO-DBT:MEH-PPV:PC71BM/Al photodiode. The PEDOT:PSS-TiO2 suspension has been spun-coated onto the ITO substrates primarily and annealed to densify the film by vaporizing water contents in the film. A ternary blend of PFO-DBT:MEH-PPV:PC71BM in optimized volumetric ratio has been sequentially spun-cast to serve as a photoactive film. Significantly improved values of the sensing parameters such as responsivity (4 mA/W) and photo-to-dark current ratio (~ 6.4 x 104) has also been found. Response/recovery times of the fabricated sensor remains almost the same (< 1 s) as previously reported for PFO-DBT:MEH-PPV:PC71BM ternary blend.
    Journal of Nanoparticle Research 08/2015; 17(9). DOI:10.1007/s11051-015-3155-6 · 2.18 Impact Factor
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    • "In concordance with in vitro experiments, many in vivo studies also showed that TiO 2 NPs, once entered the blood stream, could reach and accumulate in important organs and cause their injury. TiO 2 NPs induced damage in such organs as spleen, liver, kidney, lung, brain or heart (Chang et al., 2013; Shi et al., 2013). "
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    ABSTRACT: Titanium dioxide nanoparticles (TiO2 NPs) have found many practical applications in industry and daily life. A widespread application of TiO2 NPs rises the question about safety of their use in the context of potential occupational, environmental and intentional exposure of humans and biota. TiO2 NPs easily enter the body through inhalation, cross blood-brain barrier and accumulate in the brain, especially in the cortex and hippocampus. Toxicity of these NPs and the molecular mechanisms of their action have been studied extensively in recent years. Studies showed that TiO2 NPs exposure resulted in microglia activation, reactive oxygen species production, activation of signaling pathways involved in inflammation and cell death, both in vitro and in vivo. Consequently, such action led to neuroinflammation, further brain injury. A, spatial recognition memory and locomotor activity impairment has been also observed. Copyright © 2015. Published by Elsevier Ltd.
    Toxicology in Vitro 04/2015; 29(5). DOI:10.1016/j.tiv.2015.04.004 · 2.90 Impact Factor
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    • "In order to more clearly detect the endocrine effects of TiO 2 nanoparticles, in the experiment that explore endocrine effects of oral administration to mice of anatase TiO 2 nanoparticles, we selected 64 and 320 mg kg –1 body weight dose TiO 2 nanoparticles (LD group, 64 mg kg –1 body weight per day, and HD group, 320 mg kg –1 body weight per day). TiO 2 nanoparticles have been reported to be absorbed via oral administration and to accumulate in the liver, spleen and kidneys (Wang et al., 2007; Shi et al., 2013). In the present study, we found that after oral administration of TiO 2 nanoparticles, titanium accumulated not only in the liver, spleen and kidney, but also in the pancreas and small intestine, and also found that there was no significant difference in titanium levels between the LD and HD group (Fig. 1B "
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    ABSTRACT: There have been few reports about the possible toxic effects of titanium dioxide (TiO2) nanoparticles on the endocrine system. We explored the endocrine effects of oral administration to mice of anatase TiO2 nanoparticles (0, 64 and 320 mg kg-1 body weight per day to control, low-dose and high-dose groups, respectively, 7 days per week for 14 weeks). TiO2 nanoparticles were characterized by scanning and transmission electron microscopy (TEM) and dynamic light scattering (DLS), and their physiological distribution was investigated by inductively coupled plasma. Biochemical analyzes included plasma glucose, insulin, heart blood triglycerides (TG), free fatty acid (FFA), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 and reactive oxygen species (ROS)-related markers (total SOD, GSH and MDA). Phosphorylation of IRS1, Akt, JNK1, and p38 MAPK were analyzed by western blotting. Increased titanium levels were found in the liver, spleen, small intestine, kidney and pancreas. Biochemical analyzes showed that plasma glucose significantly increased whereas there was no difference in plasma insulin secretion. Increased ROS levels were found in serum and the liver, as evidenced by reduced total SOD activity and GSH level and increased MDA content. Western blotting showed that oral administration of TiO2 nanoparticles induced insulin resistance (IR) in mouse liver, shown by increased phosphorylation of IRS1 (Ser307) and reduced phosphorylation of Akt (Ser473). The pathway by which TiO2 nanoparticles increase ROS-induced IR were included in the inflammatory response and phosphokinase, as shown by increased serum levels of TNF-α and IL-6 and increased phosphorylation of JNK1 and p38 MAPK in liver. These results show that oral administration of TiO2 nanoparticles increases ROS, resulting in IR and increasing plasma glucose in mice.
    Journal of Applied Toxicology 03/2015; 35(10). DOI:10.1002/jat.3150 · 2.98 Impact Factor
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