Study on ultraviolet-light-excited blood fluorescence spectra characteristics

The ultraviolet light-excitated fluorescence spectra from healthy human blood in vitro have been measured by FLS920 Spectrometer, made in Edinburgh Instruments, exciting light from Xe900 - 450W steady state xenon lamp. The relation between exciting light wavelength and the fluorescence spectral characteristics of blood in the case of certain concentration is provided in this paper. Ultraviolet light excitated healthy human blood fluorescence spectra profiles change in peak intensity and position with exciting light. It may be due to the abruption of large numbers of anisomerous C-C bonds or C-N bonds that absorb the energy by non-resonance on membrane of blood cells, bringing lone-pairs of electrons, forming the new fluorophores and emit fluorescence in the case of later ultraviolet light excitation. It may be why ultraviolet light is able to kill and wound cells. In addition, the fluorescence spectra distributing range is very wide. It is due to contributions of the many fluorophores with large numbers of vibrational energy levels on the ground level in the blood cells. Our understanding of the different wavelength light-induced blood cells fluorescence spectra characteristics may be useful to development of low level laser therapy in vivo and in vitro.