Deleterious effects of sunscreen titanium dioxide
nanoparticles on DNA: efforts to limit DNA damage by
particle surface modificationy
Proc. SPIE Vol. 4258, p. 86-98,
Nanoparticles and Nanostructured Surfaces: Novel
Reporters with Biological Applications, Catherine J.
Publication Date: 06/2001
Abstract Copyright: (c) 2001 SPIE--The International
Society for Optical Engineering. Bibliographic Code:
Sunlight can have deleterious effects on humans:
causes sunburns and is the principal cause of skin
cancers. Usage of TiO2 (and ZnO) in sunscreen
lotions, widely used as UVA/UVB blockers, and intended
to prevent sunburns and to protect consumers from skin
cancers (carcinomas and melanomas) is examined. Although
used to mineralize many undesired organic pollutants,
TiO2 is considered to be a safe physical
sunscreen agent because it reflects and scatters both
UVB (290-320 nm) and UVA (320-400 nm) sunlight; however,
it also absorbs substantial UV radiation which, in
aqueous media, yields hydroxyl radial ((DOT)OH) species.
These species cause substantial damage to DNA (J.
importantly, sunlight-illuminated sunscreen TiO2
particles catalyze DNA damage both in vitro and in human
cells (FEBS Letters, 418 (1997)87). These results raise
concerns on the overall effects of sunscreens and raise
the question on the suitability of photoactive TiO2
as a sunscreen component without further studies. The
photocatalytically active nature of these metal oxides
necessitates some changes since even the TiO2
specimens currently used in suncreams cause significant
DNA strand breaks.
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