纳米二氧化硅和常规二氧化硅的水生态毒性初步研究

发布时间：2018-05-27 08:42

本文选题：纳米二氧化硅 + 形态学　；参考：《华中师范大学》2015年硕士论文

【摘要】：随着纳米科技的飞速发展,纳米材料已被广泛运用于包括工业生产、医疗器械、生物制药、化妆品以及环境污染治理等诸多领域,并产生了巨大的影响力。但由于生产和使用过程中的疏忽,纳米材料会进入到大气、水体、土壤等环境中,并对自然环境和人类健康带来的巨大的安全隐患。纳米二氧化硅(Nano-silicon Dioxide, Nano-SiO2, SiO2 NPs)目前使用较为广泛的一类纳米材料,被广泛应用于杀菌剂、涂料添加剂、电子材料、润滑剂以及医学相关领域。伴随着大量使用,可能直接或间接排放进入环境引起不利的影响。有研究证明纳米二氧化硅具有肺部毒性、心血管毒性、免疫毒性等。然而目前关于纳米二氧化硅的生态毒理研究较少。因此,本课题分别用大型蚤和斑马鱼两种模式生物来研究纳米二氧化硅的生态毒性,尤其是对水生态环境造成毒性进行评价,为其安全使用提供实验依据。第一部分通过纳米和常规二氧化硅(Normal sized Silicon Dioxide,Nor-SiO2)对大型蚤(Daphnia magna, D. magna)进行急性暴露染毒,24小时后观察其形态学(对颗粒物的摄入情况)变化,同时还对固定率(24h-EC50)和死亡率(24h-LC50)进行测算。结果显示,在纳米二氧化硅的染毒组中,大型蚤的体内检测出了纳米颗粒,并且主要集中聚集在大型蚤的鳃和肠道内,并且在高剂量处理组中(400mg/L)观察到大型蚤肠道断裂和身体破裂的情况。此外,本研究还发现随着染毒浓度的升高,固定率和死亡率都随之上升,呈现出剂量-效应关系。根据实验结果,纳米二氧化硅24h-EC50和24h-LC50分别是148.871mg/L和660.943mg/L；但在常规二氧化硅实验组中,除最高剂量处理组以外,其他处理组均未观察到颗粒物进入大型蚤体内,仅有部分颗粒物附着于大型蚤体表,,并且随着染毒浓度的升高,固定率和死亡率并没有明显上升,无剂量-效应关系存在。第二部分以模式生物斑马鱼(Zebrafish, D. rerio)为研究研究对象暴露染毒,在斑马鱼胚胎受精后的12小时,24小时,36小时,48小时,60小时,72小时,84小时,96小时分别进行形态学观察(记录斑马鱼胚胎发育情况),并且记录不同时间段斑马鱼胚胎的累计孵化率和死亡率(判断染毒材料的发育毒性),计算出受精后84小时的LC50,并分别检测纳米染毒组和常规染毒组中斑马鱼幼鱼在染毒108小时后体内MDA含量(氧化损伤指标)。结果显示,纳米二氧化硅染毒组中,斑马鱼幼鱼在各时间段均发育畸形,并且出现提前孵化情况。此外,随着染毒浓度的升高,纳米实验组的受精卵孵化率逐渐下降,并在染毒84小时后,150mg/L-300mg/L的处理组中的孵化率和对照组相比均显著降低(P0.05)；斑马鱼幼鱼的累计死亡率随着染毒浓度的增加而上升,当染毒84小时后,除50 mg/L和100 mg/L两处理组外,其他处理组的累计死亡率与对照组相比都表现出显著性差异(P0.05),计算得到LC50为240mg/L。但在常规二氧化硅染毒实验组中,各时间段均未观察到斑马鱼胚胎/幼鱼出现发育畸形以及提前孵化的现象,并且该处理组中的斑马鱼胚胎的孵化率和对照组相比并未出现明显差异；随着染毒浓度的增加,斑马鱼胚胎/幼鱼的累计死亡率和对照组相比并未显著上升。本项研究表明,Nano-SiO2与Nor-SiO2均能被大型蚤摄取,但只有纳米材料的二氧化硅能产生一定的急性毒性。本研究还发现,Nano-SiO2处理后,导致斑马鱼固定不游动甚至死亡的原因可能是引起了机体的氧化应激反应所致,并且在斑马鱼早期胚胎发育过程中,用Nano-SiO2处理,不仅可以导致受精卵提前孵化和发育不完全,同时对孵化的斑马鱼幼鱼也存在一定的毒性作用,造成较高的死亡率和氧化损伤,这说明Nano-SiO2具有一定的发育毒性作用,而常规二氧化硅并未表现出发育毒性。
[Abstract]:With the rapid development of nanotechnology, nanomaterials have been widely used in many fields, including industrial production, medical devices, biopharmaceuticals, cosmetics and environmental pollution control. However, due to the negligence in the process of production and use, nanomaterials will enter into the atmosphere, water, soil and other environments. Nano-silicon Dioxide (Nano-SiO2, SiO2 NPs) is currently using a wide range of nanomaterials, which are widely used in bactericides, coating additives, electronic materials, lubricants and medical related fields. With a large amount of use, it is possible directly or indirectly. Emissions into the environment have caused adverse effects. Studies have shown that nano silica has lung toxicity, cardiovascular toxicity and immunotoxicity. However, there are few studies on the ecological toxicology of nano silica. Therefore, this subject uses two models of fleas and zebrafish to study the ecotoxicity of nano silica. It is to evaluate the toxicity of water ecological environment and provide experimental basis for its safe use. In the first part, Normal sized Silicon Dioxide (Nor-SiO2) is used for acute exposure to the large fleas (Daphnia magna, D. magna), and the morphological changes are observed after 24 small hours. At the same time, the fixed rate (24h-EC50) and the mortality rate (24h-LC50) were measured. The results showed that the nanoparticles were detected in the body of the SiO2, and mainly concentrated in the gills and intestines of the large fleas, and the intestinal fracture and body rupture were observed in the high dose treatment group (400mg/L). In addition, the study also found that the fixed rate and mortality rate increased with the increase of the concentration, and showed a dose effect relationship. According to the experimental results, the nano silica 24h-EC50 and 24h-LC50 were 148.871mg/L and 660.943mg/L respectively, but in the conventional SiO2 experimental group, other than the highest dose treatment group. The particles were not observed to enter the large fleas, only some particles were attached to the body surface of the large fleas, and with the increase of the concentration, the fixed rate and mortality rate did not increase obviously, and there was no dose effect relationship. The second part was exposed to the research object of Zebrafish, D. rerio. The zebrafish embryos were fertilized for 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 84 hours and 96 hours, respectively (recording the development of zebrafish embryos), and recorded the cumulative hatchability and mortality of zebrafish embryos at different time periods (judging the developmental toxicity of the infected materials), and calculated the L of 84 hours after fertilization. The MDA content (oxidative damage index) of the young zebrafish fish in the nanoscale exposure group and the conventional exposure group was examined for 108 hours. The results showed that the young fish of the zebrafish fish developed malformation in each time period and appeared early hatching in the nanoscale SiO2 exposure group. In addition, the nano experimental group increased with the increase of the concentration. The hatching rate of the fertilized eggs gradually decreased and the hatchability in the 150mg/L-300mg/L treatment group decreased significantly after 84 hours of exposure to the control group (P0.05). The cumulative mortality of the zebrafish young fish increased with the increase of the concentration. After 84 hours of exposure, the cumulative death of the other treatment groups except 50 mg/ L and 100 mg/L two treatment groups. The rate of death was significantly different from that of the control group (P0.05), and LC50 was calculated to be 240mg/L., but in the conventional SiO2 exposure group, the development of zebrafish embryos / young fish was not observed at all time periods, and the hatchability of the zebrafish embryos in the treatment group was not compared with those of the control group. The cumulative mortality of the zebrafish embryos / young fish was not significantly increased compared with the control group as the concentration increased. This study showed that both Nano-SiO2 and Nor-SiO2 could be absorbed by the large fleas, but only nano silica could produce a certain acute toxicity. This study also found that Nano-SiO2 was treated and guided. The cause of non swimming or even death of zebrafish may be caused by the oxidative stress reaction of the body, and in the development of early embryo of zebrafish, Nano-SiO2 treatment can not only lead to the hatching and incomplete development of the fertilized egg, but also have a certain toxic effect on the hatched zebra fish young fish. The mortality and oxidative damage indicate that Nano-SiO2 has certain developmental toxicity, while conventional silica does not exhibit developmental toxicity.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X171.5

【相似文献】