Vol. 13, issue 03, article # 19

Abstract:

The method of laser-induced fluorescence (LIF) is widely used in investigating biological tissues. It uses pulsed UV-laser radiation to excite fluorescence in the objects under study. But the radiation itself may cause some changes in the tissues irradiated. The results of our experiments have shown some changes of LIF spectrum of a cross-striated muscle under its exposure to the UV-radiation. In particular, a noticeable attenuation of intensity within tryptophan fluorescence band (330 nm) takes place. The intensity is shown to depend on the number of pulses. At lower energy of the exciting radiation the intensity falls off more slowly. A quantitative information is obtained on the tryptophan inactivation cross section. The conclusion on commensuration of the inactivation cross sections of tryptophan and cystine within 248 nm wavelength is proved. Nonetheless, although some changes take place in the tissues exposed to laser radiation, they have not time to exceed the magnitude of random scatter for the period needed for the LIF spectra recording (~ 30 pulses), so these changes do not influence the final result.