Titanium Dioxide

General Safety References

"{D}ifferent crystalline forms of TiO2 nanoparticles have different reactivities and can differ in their toxicity despite having the same chemical composition. Anatase crystals of TiO2 are more UV-active than the rutile crystals of TiO2, resulting in the cytotoxic potency of anatase crystals being far greater than the rutile form (Sayes et al. 2006b). The UV photoactivity of metal oxide nanoparticles can be altered by adding ‘dopants’ into their crystalline structure. Also different particle sizes and surface modification of metal and metal oxide nanomaterials like silver and gold nanoparticles, can alter their internalisation after binding to cells, and the subsequent in vitro cytotoxicity (Jiang et al. 2008). For example, Uboldi et al. (2008) recently found that surface modification of gold nanoparticles (5-25 nm) with sodium citrate impaired cell viability and proliferation greater than unmodified nanoparticles, in human alveolar type-II cell lines exposed in vitro."¹

For specific information, see:

• Interim Report of the New Energy and Industrial Technology Development Organization (NEDO), Japan, entitled, "Risk Assessment of Manufactured Nanomaterials - Titanium Dioxide (TiO2), issued on October 16, 2009 (attached below)
• The report of the National Institute for Occupational Health and Safety, United States, on Occupational Exposure to Titanium Dioxide, issued in April 2011.

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1. Safe Work Australia, "Engineered Nanomaterials: Evidence on the Effectiveness of Workplace Controls to Prevent Exposure," at 28-29 (Nov. 2009)(citing Jiang W, Kim BYS, Rutka JT & Chan WCW, "Nanoparticle-mediated cellular response is size-dependent," Nature Nanotechnology 3 (March 2008), at 145-150; Sayes CM, Liang F, Hudson JL, Mendez J, Guo W, Beach JM, Moore VC, Doyle CD, West JL, Billups WE, Ausman KD & Colvin VL, "Functionalization density dependence of single-walled carbon nanotubes cytotoxicity in vitro," Toxicol Lett. 161(2), at 135-42 (2006); and Uboldi C, Barth S, Unger RE & Kirkpatrick JC, "Surface modification influences the in vitro toxicity of gold nanoparticles in human alveolar type-II cell lines," Alternatives to Animal Experimentation (ALTEX) 2008, 25 (Suppl. 1), at 74 (accessed 6 Oct. 2008)) (copyright Commonwealth of Australia reproduced by permission).