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Analysis of the optical properties of the new generation the photosensitizer hypocrellins ( HA ) of

Author: LiMingYu
Tutor: GuoMaoTian
School: Zhengzhou University
Course: Optics
Keywords: Photodynamic therapy Photosensitizer Hypocrellins (HA) Spectrum Photobleaching
CLC: R979.1
Type: Master's thesis
Year: 2007
Downloads: 126
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Abstract

Photodynamic Therapy (Photodynamic therapy, PDT) treatment of malignant tumors rise to nearly 20 years and the continuous development of a high-tech, the basic principle is the killing of tumor cells by means of light and photosensitive drug interactions generate cytotoxic substances to achieve remission and the purpose of the treatment of tumors. This paper described the PDT treatment of the basic characteristics of the tumor and its development trend, and pointed out the unique advantages of PDT treatment: the ability to selectively destroy the local primary and recurrent tumor, while not endangering the basic normal tissue; side effects, can improve patients' quality of life; convenient treatment, short course, low-cost, PDT is a very promising and worthwhile to develop treatment. In this paper, through the analysis of the main problems of the current clinical PDT technology that photosensitizing drugs currently in clinical use common defects: the absorption coefficient of the long-wave treatment, the low yield of singlet oxygen; role in wave length, the treatment of shallow depth; to normal organization phototoxic reactions; slow drug metabolism, patients must be protected from light for 4 to 8 weeks after treatment, to hinder PDT promote the use of technology in clinical. Therefore, the research and development of a new generation of photosensitizing drugs become the focus of the current PDT. In this thesis, has good prospects for the development and clinical application potential of a new generation of photosensitizers hypocrellins HA study, experimental analysis of their spectral characteristics and photobleaching characteristics, HA's hypocrellins clinical application to do some basic sex work, and to provide important reference data in order to achieve the purpose of hypocrellins HA as soon as possible for diagnosis and treatment of tumors. The main work and conclusions are summarized as follows: 1. Of the hypocrellins HA absorption spectra in different solvents, in particular the study of HA in hypocrellins three simulated body fluid solution: saline solution containing 10% human serum, saline solution and glucose saline solution The absorption spectra. HA in physiological saline solution and physiological saline containing 10% human serum, there are two strong absorption band, and there are three strong absorption band in other solvents; HA in saline and glucose saline absorption peaks are very weak, and the absorption peaks in the physiological saline solution containing 10% human serum has been enhanced. HA containing 10% human serum, physiological saline solution Soret absorption peaks compared with the solution in the other two simulated body fluids dozen nanometers redshift reveals the light absorption of the photosensitizer HA in approximation vivo environment redshift phenomenon, provide a light source for photodynamic therapy selection. Irrespective of the solvent in which the strongest absorption peak of HA are located in the absorption band is between 460 ~ 490nm. 2. The polarity of the solvent, concentration of the absorption spectra. HA absorption band maxima with increasing solvent polarity, no significant changes regularly. As the solution concentration increases, the HA also increases the absorption in the visible region, but did not change the shape of the absorption band. Whether it is at a high concentration or at a low concentration, in addition to the absorption intensity varies, the relative size and position of the absorption peak does not change, and no new absorption band appears. 3. By change of the absorption spectrum of the photobleaching characteristics of the HA were evaluated. The light sample after three absorption bands in the visible region, but the absorption zone Ⅰ moves towards the short direction 7nm. After irradiation the absorption band of the sample II, and Ⅲ position remains unchanged, however, the absorption band Ⅲ and II relative absorption band Ⅰ in ratio is reduced, especially after irradiation the absorption band Ⅲ Ⅱ in the intensity ratio of the absorption band intensity decreases faster . Analysis of the reasons may be photosensitive molecules autoxidation. Light in the bleaching process, the color of the HA gradually become yellowish, continue to light, the HA the color no longer changed, and then absorb no change in the spectrum shape. Decreases rapidly at the beginning of photobleaching, after a period of time, slow down the rate of photobleaching. Obtained by exponential fitting the photobleaching of HA to the half-life of about 4 hours, but this is only a preliminary experimental results, pending further experimental study. When the same photosensitizer concentration, optical bleaching time with the increase in the excitation light power decreases. 4. Temperature, concentration, excitation wavelength excitation intensity of the fluorescence spectra. HA a strong fluorescence emission band (I), about 600nm and 650nm about a weak emission band (II). As the concentration increases, the proportion of (II / I) of the value of the two emission peaks almost unchanged. HA cryogenic fluorescence spectroscopy and room temperature fluorescence spectroscopy, two emission bands in the visible region, the emission band position is basically nothing changes, but the ratio of the two emission peaks Ⅱ / Ⅰ room temperature ratio relative ratio has been reduced, the the HA fluorescence spectra shape does not vary with the excitation wavelength is changed. Weak excitation fluorescence spectra no obvious differences between the excitation intensity reaches a certain value, the fluorescence spectrum will change significantly increased emission band II. Finally, The hypocrellins a potential application of the photosensitizer, has been shown to have significant photodynamic activity. The study is still very slow progress. As phototherapy drugs, hypocrellins for the clinical long distance. To realize the clinical application of hypocrellins must seek a wide range of cooperation, so that the physical realm, the field of chemistry, the biological field and medical researchers in the field are involved.

Analysis of the optical properties of the new generation the photosensitizer hypocrellins ( HA ) of

Abstract

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