| Photodynamic therapy(PDT) is mainly used for tumour diagnosis and treatment as a new treatment which different from modern medicine, surgery,chemotherapy and radiation therapy. Since the late 1970 s, scientists have done lots of research on PDT. Among them,photosensitizer as one of the three elements of PDT has been studied and improved a lot. Currently, PDT has lots of advantages such as high selectivity, low toxicity, repetitive treatment and so on, which has been applied in clinic. However, there are still some problems, such as penetration depth shallow, unstable curative effect. For these two problems, in this paper,we proposed to use near-infrared light to excite the photosensitizer and study the dosage of the photosensitizer.The optical properties and photosensitivity of Tm3+ singly doped Na Yb F4 nanocrystalline materials were carried out. In this paper, Tm3+: Na Yb F4 single doped nanocrystalline materials have been prepared by solvothermal method. By measuring the 800 nm fluorescence peak which from 3H4 â†' 3H6 transition and the production rate of singlet oxygen, it can be found that the fluorescence intensity increased linearly with the concentration of Tm3+ increased firstly, and then slowly increased after the linear increasing trend. The fluorescence intensity locatd at 800 nm got the maximum value when the doping concentration of Tm3+ is 2.0%. The production rate of singlet oxygen decreased slowly with the concentration of Tm3+increased, and then showing an approximation linear downward trend after the gentle decline. In order to achieve the dual-function of photosensitizer which can be used for imaging detecting and PDT, the concentration of Tm3+ has been optimized,the optimal doping concentration is confirmed to be about 1.3%.The properties of Tm3+:Na Yb F4 mixed nanocrystals and single doped nanocrystalline materials were compared. In this work, the 2.0% Tm3+:Na Yb F4 single doped nanocrystalline material corresponding the strongest luminescence was mixed with Na Yb F4 nanocrystalline by physical method to get the mixed nanocrystal with different doping concentration. By study the fluorescent spectra and production rate of singlet oxygen, the trend of fluorescent intensity changed with the concentration of Tm3+ increasing was got, it can be found that the trend is similar but faster changed than the trend for the single doped nanocrystal. When the concentration of Tm3+ is below 1.1%, the production rate of singlet oxygen in mixed noncrystalline is smaller than that in the single doped noncrystalline. When theconcentration of Tm3+ is above 1.1%, the production rate of singlet oxygen in mixed noncrystalline is bigger than that in the single doped noncrystalline. Then the doping concentration of Tm3+:Na Yb F4 was optimized, finding that the optimal doping concentration is about 0.95%. To realize the double functional of photosensitizer, after analyzing, the mixed crystalline material is better than the single doped material.The photosensitivity of Gd3+ doped Na Yb F4 nanocrystalline materials was carried out. The morphology of the Gd3+: Na Yb F4 nanocrystals was of characterized by TEM, and got that the particle disperse well and the particle size was about 25 nm. By measuring the production rate of singlet oxygen of Gd3+:Na Yb F4, it can be found that the production rate of singlet oxygen decreases with the increase of Gd3+doping concentration, and it is proportional to the concentration of nanocrystals of Yb3+. |
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