New Promising Photosensityzers for Photodynamic Laser Therapy

Abstract

Photodynamic therapy of tumour is whidly spread now both in experimental and clinical oncology. Great progress in care of some diseases has been achieved. However, used now photosensityzers are not provide some requirements. For example almost anyone has low extinction coefficients (1 10’-4 lo‘ M-’ cm-’) in the visible range, where biology tissues have low transparency. We synthesized dyes for the ”therapeutic window” of biology tissues (extinction coefficients are of 1 10”-3 l o ” M-’ cm-’1. Besides, for the spectral range of extinction maxima (760-830 nm) there are reliable and simple for operation laser diodes, which can be used as irradiation sources for investigations of photodynamic efficiency. Spectral and photochemical parameters of synthesized dyes in organic solvents and water with concentrations of l O ‘ l O ’ have been investigated. Dyes in organic solvents were defined to be mainly in monomeric form. The water importing promotes the formation of H-aggregates of dyes. On the luminescence properties the singlet oxygen generation of investigated dyes has been identified. Quantum yield of the singlet oxygen generation has been estimated. The oxygen sensitizing was defined to be due to nonradiative energy transfer from triplet dye molecules to oxygen. Photophysical and photochemical properties of six dyes in vitro with the two order variation of the yield of the synglet oxygen generation have been investigated. The method of dye import into tumour cells HeLa has been developed. The accumulation of investigated dyes in tumour cells has been observed. Spectral analysis of accumulated dyes got only monomer forms in HeLa cells. Spectral and polarization measurements were used to investigate the environmental variation of dyes in culture media tumour cells. It was shown that dye molecules in culture media are aggregated with the albumen. Tests of photodynamic efficiency of six dyes in the tumour cells have been made. Five of them shown evident effect of cell killing under the irradiation in the spectral range of photosensitizer absorption. Optimal doses of optical irradiation for each agent in the range 36-73 J/cm’ have been defined. The correlation between the yield of the singlet oxygen and photodynamic properties of dyes have been determined. 11 :oo QThE1 Investigation of Above-Tlirrsliold-Ionization: Influence of an Elliptical Polarization of the Rndiation