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Title: | 脂質修飾之量子點其毒性分析 The cytotoxicity analysis of quantum dots coated with lipids |
Authors: | Hui-Tzu Chang 張慧慈 |
Advisor: | 張富雄(Fu-Hsiuan Chang) |
Keyword: | 量子點,脂質,細胞毒性, quantum dots,lipids,cytotoxicity, |
Publication Year : | 2007 |
Degree: | 碩士 |
Abstract: | 量子點是一種由半導體金屬合成之奈米粒子。量子點具有比一般螢光物質優勢的光學與電子特性,包括:高效能的量子產率 ( quantum yield )、高莫耳消光係數 ( molar extinction coefficients )、顯著的斯托克斯位移 ( Stokes shift )、吸收光譜範圍廣且具有狹窄並對稱的螢光光譜 ( photoluminescence spectra ) 和能夠有效抵抗光褪色作用及光學或化學傷害之特性等。另外,量子點的螢光是隨著顆粒大小而不同,因此,在單一光源下可同時觀察不同大小的量子點。
這些獨特性質使量子點能被應用在生物醫學上,但關於奈米科技仍有許多未知的領域,比如人體直接暴露奈米物質可能有健康的危害性。因此,本實驗研究目的為探討以中性脂肪DPPC包覆之量子點,藉由融合蛋白Tat-SA ( Tat-streptavidin ) 攜帶量子點進入細胞後,量子點對HeLa細胞和CT26細胞的細胞毒性;並藉由動物實驗,了解量子點在動物體內分佈範圍與代謝器官。 本實驗利用MTT assay與LDH-release assay測定細胞粒腺體代謝活性與細胞存活率,作為細胞毒性的指標。首先,直接將修飾之量子點處理HeLa細胞和CT26細胞,結果發現,HeLa細胞和CT26細胞皆在特定量子點濃度下,其細胞代謝活性與存活率有明顯下降趨勢。比較不同量之融合蛋白Tat-SA攜帶量子點在細胞遞送之情況,發現細胞內量子點亮點因為融合蛋白Tat-SA而增加。分析融合蛋白Tat-SA攜帶量子點進入細胞後的細胞毒性,結果顯示,量子點的內在化對HeLa細胞和CT26細胞似乎沒有太大影響。而在動物實驗中,藉由原子吸收分析儀測定量子點的鎘含量,發現肝臟和腎臟的鎘含量最高,因而推測肝臟和腎臟可能是代謝量子點的主要器官。 藉由以上的毒性分析,將有助於量子點在細胞標定與活體實驗的應用。 Semiconductor nanoparticles, Quantum dots ( QDs ), have the optical and electrical properties better than the fluorescence molecules, including high quantum yield, high molar extinction coefficients, great effective Stokes shift, broad absorption with narrow, symmetric photoluminescence ( PL ) spectra spanning the UV to near-infrared ( NIR ) and resistance to photobleaching and photo- or chemical degradation. In addition, the size-tunable fluorescence properties of QDs allow detection of multiple QDs excited by a single light source. The unique properties of QDs make them apply in biologic and medicine. But the nanotechnology frontier leaves many areas unexplored, or under-explored, such as the potential adverse human health effects resulting from exposure to novel nanomaterials. In this study, QDs were coated with neutral lipids, DPPC, and conjugated with Tat-streptavidin (Tat-SA) fusion proteins to facilitate intracellular delivery. Followed, we analyzed the cytotoxicity of HeLa cells and CT26 cells treated with QDs conjugated Tat-SA proteins. And finally, QDs were injected to the rate to see the distribution of QDs in vivo To test the potential cytotoxicity of QDs, MTT assay and LDH-release assay were used to examine the cellular metabolic activity and cell viability. First, HeLa cells and CT26 cells were treated with different concentration of QDs/DPPC and detected the cytotoxicity by MTT assay and LDH-release assay. The results revealed that the cell viability and cellular metabolic activity of QDs-treated HeLa cells and CT26 cells decreased at QDs concentration of 1.875μg/mL and 2.5 μg/mL, respectively, compared with control. From the fluorescence images, the Tat-SA proteins actually improved the intracellular QDs density in the HeLa cells and CT26 cells, and the results of cytotoxity assays showed that ODs internalization did not affect the cellular metabolic activity and cell viability. In vivo studies, the atom absorption spectrometer ( AAS ) were used to detect cadmium (Cd2+) concentration of organs and blood. The results supported that liver and kidney were the major metabolic organs of QDs, because of the higher cadmium concentrations in these two organs. These results of QDs cytotoxicity analysis could be used as references of QDs in cell labeling and in vivo studies. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/28244 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 生物化學暨分子生物學科研究所 |
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