Objective To synthesize a quantum dot (QD) to recognize glioma cells for imaging and photodynamic therapy. Methods By one-pot aqueous approach, near infrared-emitting CdTe was produced. After detection of its physicochemical characterizations, RGD was conjugated. Emission images were observed with confocal microscopy. To test its toxicity, CdTe-RGD with various concentrations was separately added into U251 and 3T3 cells for incubation in dark circulation. To test its photodynamic effect, U251 and 3T3 cells were then irradiated for 5 ~ 60 min using 632.8 nm laser. Results The QD (Φ = 3.75 nm, PL peak wavelength =700 nm, PLQY=20%) achieved was a spherical crystal with excellent monodispersity. Under confocal microscope , U251 cells were visualized but 3T3 cells not. In dark circulation, the survival rates of both U251 and 3T3 cells were above 85%. After laser irradiation, the survival rate of U251 cells decreased to (37 ± 1.6)%with the increasing of irradiation time and CdTe-RGD concentration. Conclusion With good physicochemical characterization and low toxicity, CdTe-RGD could be applied in biomedical imaging and photodynamic therapy of gliomas.%目的:合成近红外量子点并验证其荧光成像和光动力效应.方法:应用一锅法水相合成近红外量子点CdTe,经表征检测后连接RGD多肽,再用激光共聚焦显微镜观察其荧光成像效果. 随后,将3 ~ 24μg/mL的CdTe-RGD分别加入U251和3T3细胞,避光培养24 h间,观察量子点的细胞毒性.最后用强度为30 mW/cm2,波长为632.8 nm的激光照射量子点处理后的细胞5 ~ 60 min,观察其光动力效应. 结果:合成的CdTe具有良好的晶体结构和分散性,其直径为3 . 75 nm ,发射波长700 nm ,荧光产率20%. 经量子点处理后,U251细胞可荧光显像而3T3细胞则不能.暗环境下,不同浓度CdTe-RGD处理过的U251和3T3细胞存活率都在85%以上. 激光照射后, 随光照时间延长和量子点浓度的增加,U251细胞存活逐渐下降至(37 ± 1.6)%. 而3T3细胞组的存活率则无明显变化. 结论:一锅法水相合成的CdTe-RGD具有良好的理化性质且细胞毒性低,在生物成像和光动力治疗方面具有应用前景.
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