Studies On Spectroscopy Characteristic Of The Interaction Between Light And Bio-Tissue

Light induced fluorescence spectra and its characteristic of human blood and thioredoxin reducase (TrxR), and the spectroscopic detection of hypercholesterolemia serum are systemically investigated in experiment and theory.Based on the fact that the profile, the change tendency with the blood concentration change, and the excitation mechanism of fluorescence from human blood are similar to those from laboratory rats' blood, it is first proposed that rat blood can be used as human blood to investagate the characteristic and the production mechanism of blood fluorescence spectra and the corresponding biological effects.Experimental results of LED light (λ=457 nm), Ar~+ laser (λ=457.9 nm) and He-Ne laser (λ=632.8 nm) induced whole blood fluorescence spectra indicate that using laser as excitation light can exhibit a part of fine structure of blood cell spectra, which suggests that fluorophores have a selective absorption to the wavelength of the exciting light and this selectivity are dependent on the energy level structure and the state of the fluorophores. In addition, the fluorescence spectra of blood excited by He-Ne laser is much lower than the other two. As a result, the photobiological effect of He-Ne laser is smaller. Since the biological effect of lower power laser is bi-directional and cumulative, it is easy to control the irradiation doze and the effectiveness if He-Ne laser is used in clinical therapy of the intravascular low-level laser irradiation (ILLLI).The fluorescence polarization of whole blood induced by LED polarized light at 407 nm and its variation rules with the blood concentration are investigated by experiment. Based on the theory of energy transfer, the energy transfer mechanism in different fluorescence areas, under different concentrations of whole blood as well as the variation mechanism of polarized degree are discussed.The spectroscopy characteristic of normal human serum and the hypercholesterolemia serum indicate that both the absorption spectra and the fluorescence spectra of hypercholesterolemia serum are different from those of normal human serum. Thus, the abnormal content of cholesterol in serum can be judged by comparing the absorption and fluorescence spectra.The fluorescence spectra of TrxR solution from human brain excitated by violet LED light at 407 nm and Ultra-violet light at 253.7 nm are investigated for the first time. The...