Biological and physical constrains of multiphoton fluorescence microscopy of biotissues

摘要

We have performed theoretical and experimental researches of spatio-temporal structure of femtosecond laser pulses, scattered in suspension of polysterol beads in water. The spatio-temporal structure of scattered pulses was measured by means of nonlinear optical gating at noncollinear second harmonic generation with subpicosecond temporal resolutions. Testing of phototoxic action of high-intensity femtosecond pulses on biological tissues has been performed with serum of rat's blood. Samples were irradiated with trains of 50-fs Ti:sapphire laser pulses with intensity up to a threshold of optical breakdown. The phototoxic stress of blood serum was defined with a several techniques including biochemoluminescence, sonoluminescence, and morphology analysis of dehydrated droplet, total concentration of proteins, viscosity and proteins oxidation measurements. We have determined regimes of blood serum irradiation with IR femtosecond laser pulses, corresponding to nonivasive influence, phototoxic stress and optical damage.