- 學位論文
應用聚酸酐共聚物調控CdSe/ZnS量子點表面化學之研究
Study of Surface Chemistry of Controlling CdSe/ZnS Quantum Dots by PMAO-based Block Copolymers
摘要
由於量子點擁有獨特的光學性質，近幾年來已逐漸取代傳統染劑在細胞標定之應用，相關生物接枝技術也漸趨成熟，可依不同應用需求，接枝上各式各樣的功能性分子，發展潛力也被看好。本文目的為改善兩性高分子改質量子點所造成的樣品損耗，以及傳統生物接枝方式效率較低的問題，並降低細胞毒性問題。本實驗引用一種新穎的生物接枝方式，有別於傳統水相生物接枝的方法，將生物接枝反應改到有機相進行，利用兩性高分子（poly(maleic anhydride-alt-1-octa- decene), PMAO）於有機相接枝聚乙二醇、特丁基對苯二酚等分子，形成聚酸酐共聚物，免去交聯劑之使用，降低交聯劑殘留所造成的潛在危險，也降低實驗成本。過去我們利用EDC（碳二醯胺類交聯劑）進行生物接枝，然而，EDC對於反應環境有嚴苛限制，影響其接枝效率，倘若單獨使用EDC不添加其他輔助試劑，會有殘留現象，可能帶來的後遺症目前還不可知。 另外為改善非特異性鍵結對細胞造成之毒性問題，在PMAO表面接枝抗氧化劑—特丁基對苯二酚（Tert-butyl hydroquinone，TBHQ），形成PMAO/TBHQ共聚物，與PMAO/PEG莫耳比1：1混合對量子點進行包覆，利用MTT試劑做細胞活性檢測，證實PMAO/TBHQ與PMAO/PEG的組合可提升量子點之生物相容性（biocompability）；另以螢光顯微鏡觀察，證實PMAO/TBHQ與PMAO/PEG的組合可降低量子點對細胞形成非特異性鍵結（non-specific binding）之傷害。
並列摘要
Quantum dots have been regarded as a powerful probe for biomolecule labeling in biomedicine since the end of 20th century due to their high quantum yield and low photobleaching. These characteristics are also essential for probes applied to bioimaging, labeling or targeting. In the past, we utilized cross-linkers, as EDC (carbodiimide crosslinker), to conjugate biomolecules on the surface of quantum dot. Unformchanely, there are three possible pathways of EDC mechanism. In order to avoiding the side-effects and concerning economic benefits, we choose another method to replace EDC chemistry. In order to replace EDC chemistry, we use another method. PMAO molecules contain lots of anhydride rings and those anhydride rings are strongly reactive to amino groups in organic phase. So that molecules containing amino groups or hydroxyl groups could react with PMAO and form a stable compound in organic solvent. Based on this role, we could also synthesis PMAO/PEG and PMAO/TBHQ block copolymers in organic solution. The effiviency of polymerilation were determined by FT-IR. From the results of MTT assay, we found that using PMAO/PEG and PMAO/TBHQ mixtures to wrap quantum dots could increase biocompability. Otherwise, we also observed by fluorescent microscopy that quantum dots wrapped by such mixtures could decrease the phenomenon of non-specific binding between quantum dots and cells.