【摘要】：目的開發(fā)一種新型超順磁性納米材料Pt3Co，探討其作為T2造影劑用于活體磁共振成像（magnetic response imaging，MRI）的可行性及價值。 方法①合成磁性納米顆粒Pt3Co，采用十八碳烯聚乙二醇（polyethylene glycol，PEG）修飾其水溶性得到Pt3Co-PEG，并對其穩(wěn)定性、表征及磁性特征進行研究。②將小鼠乳腺癌細胞4T1、人乳腺癌細胞sk-br-3、正常人肝細胞HL-7702及人腎上皮細胞293T分別與不同濃度Pt3Co-PEG結(jié)合，通過MTT比色法、乳酸脫氫酶（LDH）泄露試驗及細胞內(nèi)活性氧（ROS）檢測實驗進行Pt3Co-PEG體外毒性研究。③將荷4T1腫瘤的兩組雌性Balb/c小鼠分別經(jīng)尾靜脈注射相同劑量的Pt3Co-PEG和Resovist（商用MR T2造影劑），于不同時間點（2h、6h、24h）進行小鼠腫瘤組織及肝臟的T2成像，并測量其T2信號值。④經(jīng)尾靜脈注射一定量Pt3Co-PEG的5組（包括1組對照組）同周齡健康雌性Balb/c小鼠，于注射后不同時間（1d、7d、30d、60d）用摘眼球法取血，，進行血常規(guī)及血生化分析；同時取其包括肝臟、脾臟、腎臟、心臟、肺臟、小腸等在內(nèi)的主要器官組織進行蘇木精和伊紅（HE）染色；以此來實現(xiàn)活體長期毒性監(jiān)測。⑤在④中每組小鼠取過血及主要臟器后，再取其肝臟、脾臟、腎臟、心臟、肺臟、小腸、骨骼、肌肉及皮膚等器官組織，通過燒ICP法檢測Pt、Co元素在小鼠體內(nèi)的生物分布狀況。 結(jié)果①透射電子顯微鏡下，Pt3Co呈均勻分布的顆粒狀，粒徑約6nm；經(jīng)PEG修飾后，Pt3Co-PEG在不同生理溶液中均有較好的穩(wěn)定性；磁滯曲線顯示Pt3Co-PEG具有超順磁性；近紅外圖顯示吸收波長3000cm-1處有修飾的十八碳烯聚乙二醇分布；3.0T磁共振成像儀測得Pt3Co-PEG的T2弛豫率可達451.2mM/s，遠遠高于商用T2造影劑Resovist（其T2弛豫率約為193.4mM/s）；②系列體外毒性實驗顯示Pt3Co-PEG在較高濃度時亦未見明顯細胞毒性；③兩組荷4T1小鼠模型尾靜脈注射相同劑量Pt3Co-PEG和Resovist后，隨著時間的推移，Pt3Co-PEG組小鼠腫瘤區(qū)域的T2信號值降低幅度明顯大于Resovist組，而兩組的肝臟部位T2信號變化趨勢相似；④活體長期毒性實驗結(jié)果顯示，血生化、血常規(guī)指標均在正常范圍內(nèi)；主要臟器HE染色與對照組相比未見明顯差異；⑤長期生物分布結(jié)果顯示，在小鼠尾靜脈注射一定量的Pt3Co-PEG60d以后，Pt、Co元素在肝、脾及小腸中仍有較高量的殘留，該問題有待通過改善Pt3Co-PEG磁性納米顆粒的表面修飾來解決。 結(jié)論超順磁性納米顆粒Pt3Co-PEG在生理環(huán)境下具有較好的穩(wěn)定性和極強的順磁性。小鼠體內(nèi)MR成像結(jié)果顯示Pt3Co-PEG能明顯降低肝臟及腫瘤組織的T2信號，尤其在腫瘤部位的成像效果優(yōu)于目前商用造影劑Resovist。經(jīng)過長期系統(tǒng)的體內(nèi)外毒性實驗及生物分布結(jié)果顯示，雖然Pt3Co-PEG在生物體內(nèi)有一定量的殘留，但沒有明顯的生物毒性。因此，本實驗組合成的Pt3Co-PEG有望成為新一代的高效MR T2造影劑，用于腫瘤診斷。
[Abstract]:Objective to develop a new type of superparamagnetic nanomaterials (Pt3Co,) to explore the feasibility and value of using as T2 contrast agent for in vivo magnetic resonance imaging (magnetic response imaging,MRI). Methods 1Magnetic nanoparticles Pt3Co, were synthesized by modifying their water solubility with octadecene polyethylene glycol (polyethylene glycol,PEG) to obtain Pt3Co-PEG, and their stability, characterization and magnetic properties were studied. 2Murine breast cancer cells 4T11, Human breast cancer cell sk-br-3, normal liver cell HL-7702, and human renal epithelial cell 293T, combined with different concentrations of Pt3Co-PEG, were determined by MTT colorimetry. Lactate dehydrogenase (LDH) leakage test and intracellular reactive oxygen species (ROS) assay were used to study the toxicity of Pt3Co-PEG in vitro. 3 the same dose of Pt3Co-PEG was injected into the tail vein of two groups of female Balb/c mice bearing 4T1 tumor. And Resovist (commercial MR T2 contrast agent), At different time points (2 h, 6 h, 24 h), T2 imaging of tumor tissue and liver of mice was performed and their T2 signal values were measured. 4 healthy female Balb/c mice of the same week age were injected with a certain amount of Pt3Co-PEG via caudal vein (including a control group). At different time after injection (1 d, 7 d, 30 d, 60 d), the blood was extracted by eyeball extraction method, and the blood routine and blood biochemical analysis were carried out. At the same time, the main organs including liver, spleen, kidney, heart, lung and small intestine were stained with hematoxylin and eosin (HE). 5 after blood and main organs were taken from each group of mice, the liver, spleen, kidney, heart, lung, small intestine, bone, muscle and skin and other organs and tissues were taken to detect Pt, by burning ICP method. Biodistribution of Co in mice. Results 1 under the transmission electron microscope, Pt3Co showed a uniform particle size of about 6 nm. After PEG modification, Pt3Co-PEG had good stability in different physiological solutions, and the hysteresis curve showed that Pt3Co-PEG had superparamagnetism. Near infrared images showed that there was a modified octadecene polyethylene glycol distribution at the absorption wavelength of 3000cm-1. The T2 relaxation rate of Pt3Co-PEG measured by 3.0T MRI was 451.2 mm / ml, which was much higher than that of commercial T2 contrast agent Resovist (the T2 relaxation rate was about 193.4mM/s). A series of in vitro toxicity tests showed that there was no obvious cytotoxicity of Pt3Co-PEG at higher concentration. 3After the same dose of Pt3Co-PEG and Resovist were injected into the tail vein of the 4T1-bearing mice in the two groups, the decrease of T2 signal value in the tumor area of the Pt3Co-PEG group was significantly higher than that of the Resovist group with the passage of time, while the trend of T2 signal change in the liver of the two groups was similar. (4) the results of long-term toxicity test in vivo showed that the blood biochemical and routine indexes were within the normal range, and there was no significant difference in HE staining between the main organs and the control group. 5 the results of long-term biodistribution showed that after a certain amount of Pt3Co-PEG60d was injected into the tail vein of the mice, there were still high levels of Pt,Co residues in the liver, spleen and small intestine. This problem needs to be solved by improving the surface modification of Pt3Co-PEG magnetic nanoparticles. Conclusion superparamagnetic nanoparticles Pt3Co-PEG have good stability and strong paramagnetism in physiological environment. The results of MR in mice showed that Pt3Co-PEG could significantly decrease the T2 signal of liver and tumor tissue, especially in the tumor site, which was better than that of commercial contrast agent Resovist. at present. After long-term systematic in vitro and in vivo toxicity test and biological distribution results, although there is a certain amount of Pt3Co-PEG residues in organisms, there is no obvious biotoxicity. Therefore, the combined Pt3Co-PEG is expected to be a new generation of high efficient MR T2 contrast agent for tumor diagnosis.
【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：R445.2

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