Upper epidermis autofluorescence dynamics under laser UV irradiation

In the present work the temporal behavior of autofluorescence of upper (30 - 40 micrometers ) layer of human skin under continuous 337 nm laser exposure was investigated. The samples were prepared using epidermis stripping technique. Kinetic curves of autofluorescence decay at 420 nm, 440 nm, and 460 nm have been obtained. In double exponential approximation (I(t) equals a exp(-t/(tau) 1)+ b exp(-t/(tau) 2)+ c) the parameters of autofluorescence decay have been evaluated. Under the assumption that different terms in double exponential approximation correspond to different individual fluorophors the contribution of fast bleaching, slowly bleaching, and non-bleaching components to fluorescence spectrum of the sample at 420 nm, 440 nm, and 460 nm have been calculated.