Faunce, Thomas

The Medical Journal of Australia

English

The Australian National University

MJA • Volume 190 Number 8 • 20 April 2009 463LETTERS  Safety of nanoparticles in sunscreensThomas A FaunceTO THE EDITOR: More than 1000 sun-screen products are marketed in Australia,and an increasing proportion (about one-third) incorporate engineered nanoparti-cles (ENPs). Defined as manufactured par-ticles having one or more dimensions lessthan 100 nm (0.00001 cm), ENPs exploitthe altered chemical reactivity and otherchanges that reduction to nanosize elicits.ENPs in sunscreen, such as titanium diox-ide (TiO2) and zinc oxides, constituteeffective broad-spectrum ultraviolet radia-tion (UVR) blocking agents with enhancedcosmetic transparency. The AustralianTherapeutic Goods Administration (TGA),in approving such products, has statedthat “there is no evidence that sunscreenscontaining these materials pose any risk tothe people using them”.1 Similarly,authors of a recent article (written incollaboration with representatives of acosmetic company) interpret the evidenceas confirming that ENPs do not penetratebelow the stratum corneum, or only insmall amounts, producing limited cellulartoxicity.2 Information on sunscreen pack-aging is not required to disclose the pres-ence of ENPs.Yet, when TiO2 nanoparticles are incor-porated into human cells in vitro, mobili-sation of electrons by absorption ofultraviolet A (UVA) light produces reactiveoxygen species and causes DNA damage(strand breakage and base modification).In fact, TiO2 has been used in this way tokill cancer cells in vitro.3 In sunscreensand cosmetic preparations, TiO2 is oftencoated to reduce this photocatalytic activ-ity because over 90% of ambient UVR isUVA. However, ev idence has nowemerged that TiO2 in uncoated anataseform has been added to a marketed but asyet undivulged Australian sunscreen — inthis form, TiO2 is capable of producingdamaging photocatalytic free-radical reac-tions on particular steel roofing materials.4Likewise, zinc oxide ENPs manufacturedfor use in sunscreens are potent biocidesand subject to disposal restrictions inmost countries.Despite the TGA’s stance, existingresearch does not comprehensively ensurethe safety of all ENPs in sunscreens, par-ticularly ENPs less than 40 nm in sizeapplied long term to human skin that isimmature, aged, diseased, damaged, hairyor covering flexural creases.5 The non-government organisation Friends of theEarth has compiled a list of sunscreensavailable in Australia that are claimed bythe manufacturers to be free of nanopar-ticles.6 A New South Wales Governmentcommittee has recommended that, for reg-ulatory purposes, ENPs be considerednew chemical entit ies that requireincreased safety data.7 Policymakersshould increase funding for objectiveresearch in this area (such as that byMacquarie University and the flagshipproject in nanotechnology of the CSIRO[Commonwealth Science and IndustryResearch Organisation]). Until such safetydata are available, the TGA should applythe “precautionary principle”5 and, at aminimum, increase packaging informationabout nanoparticles in sunscreens.Thomas A Faunce, Associate ProfessorMedical School and College of Law, Australian National University, Canberra, ACT.Thomas.Faunce@anu.edu.au1 Therapeutic Goods Administration. Safety of sun-screens containing nanoparticles of zinc oxide ortitanium dioxide. Canberra: TGA, 2006. http://www.tga.gov.au/npmeds/sunscreen-zotd.htm(accessed Dec 2009).2 Nohynek GJ, Lademann J, Ribaud C, Roberts MS.Grey goo on the skin? Nanotechnology, cosmetic andsuncreen safety. Crit Rev Toxicol 2007; 37: 251-277.3 Hirakawa K, Mori M, Yoshida M, et al. Photo-irradiated titanium dioxide catalyzes site specificDNA damage via generation of hydrogen peroxide.Free Radic Res 2004; 38: 439-447.4 Baker PJ, Branch A. The interaction of modernsunscreen formulations with surface coatings. ProgOrg Coatings 2008; 62: 313-320.5 Faunce TA, Murray K, Nasu H, Bowman D. Sun-screen safety: the precautionary principle, the Aus-tralian Therapeutic Goods Administration andnanoparticles in sunscreens. NanoEthics 2008; 2:231-240.6 Friends of the Earth. Nanotechnology project.http://nano.foe.org.au/node/286 (accessed Jan2009).7 New South Wales Government Standing Commit-tee on State Development. Nanotechnology inNew South Wales. Sydney: NSW Government,2008. http://www.parliament.nsw.gov.au/prod/PAR LMENT/co mmit tee.n sf /0 /35 D2E3 E37498A908CA2574F1000301BB (accessed Jan 2009). ❏

Safety of Nanoparticles in Sunscreens

https://openresearch-repository.anu.edu.au/bitstream/1885/21894/2/01_Faunce_Safety_of_Nanoparticles_in_2009.pdf

Safety of Nanoparticles in Sunscreens

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