The present pilot study tested the efficiency of nanoTiO2
sunscreen to prevent the oxidative stress/
inflammation caused by ultraviolet (UV) radiation using
biomarkers in subjects' blood, urine, and exhaled breath condensate (EBC). In addition, the skin absorption of nanoTiO2 was studied. Six identical subjects participated in three tests: (A) nanoTiO2
sunscreen, (B) UV radiation, and (C)
sunscreen + UV. The first samples were collected before the test and the second after
sunscreen application and/or UV exposure. On day 4, the third samples were collected, and the
sunscreen was washed off, and the fourth samples were collected on day 11. The following
biomarkers were measured:
malondialdehyde, 4-hydroxy-trans-hexenal, 4-hydroxy-trans-nonenal,
aldehydes C6-C12, 8-iso-Prostaglandin F2α, o-
tyrosine,
3-chlorotyrosine,
3-nitrotyrosine, 8-hydroxy-2-deoxyguanosine,
8-hydroxyguanosine, 5-hydroxymethyl
uracil, and
leukotrienes, using liquid chromatography-electrospray ionisation-tandem mass spectrometry.
Titania was measured using inductively coupled plasma mass spectrometry and TiO2 nanoparticles by transmission and scanning electron microscopy.
Sunscreen alone did not elevate the markers, but UV increased the
biomarkers in the plasma, urine, and EBC. The
sunscreen prevented skin redness, however it did not inhibit the elevation of oxidative stress/inflammatory markers.
Titania and nanoTiO2 particles were found in the plasma and urine (but not in the EBC) in all
sunscreen users, suggesting their skin absorption.