Investigation of the Photobleaching Effect on the Measurement of Laser-Induced Fluorescence Excitation-Emission Matrices of Biological Tissues

摘要

Photobleaching effect on laser-induced fluorescence excitation-emission matrices of biological tissues was investigated. Rat brain tissues were used as an object of study. Tunable laser was used as an excitation source with wavelength in 210-290 nm range with 10 nm steps. The fluorescence spectra were measured depending on irradiation dose and wavelength. The photobleaching rate was estimated as an absorbed radiation dose when peak fluorescence intensity decreases 2.7 times. The above level of intensity decrease is achieved at absorbed dose of 58 mJ/cm~2 for the 210 nm wavelength, and at 2550 mJ/cm~2 for 290 nm. The highest absorbed dose (4333 mJ/cm~2) and respectively the lowest bleaching rate falls on 250 nm. It had been shown that higher photobleaching rate at shorter wavelengths in general has negligible effect on the excitation-emission matrices measurements.