A novel analytical technique of skin photo-stress biomarker using surface plasmon resonance

It is possible that protein carbonylation in the stratum corneum might be used as an index of skin photo-stress. In order to evaluate the relationship between the protein carbonyl / total protein ratio (carbonylation ratio) and skin photo-stress, the authors established a methodology by which protein carbonyl can be quantitatively analyzed using an optical technique based on surface plasmon resonance (SPR). Firstly, the protein carbonyl was reacted with 2,4-Dinitrophenylhydrazine (DNP), and the quantity of DNP-protein carbonyl was determined using an anti-DNP antibody. The mass of DNP-protein carbonyl was measured using SPR. A significant difference was observed in the carbonylation ratio between a sun-protected area (mid-ventral arm) and a sun-exposed area (upper cheek, p < 0.05). Moreover, the carbonylation ratio of the sun-exposed area showed a higher value than that of the sun-protected area. It was suggested that the carbonylation ratio might be a useful index of skin photo-stress.