| 摘要: | 本研究的主要目的為：以不同親水改質方法對量子點(quantum dots) A. 螢光性質，B. 生理環境下的穩定性，C. 不同細胞的吞噬性之影響，並希望利用經過親水化改質後的量子點來標定動物細胞。分別測試氫硫基化合物MPA (Mercaptopropionic acid)、兩性高分子(Poly(maleic anhydride alt-1-tetradecene))與磷脂質(1,2-Distearoyl-sn- Glycero-3-Phospho-ethanolamine-N-[Amino(Polyethylene Glycol) 2000])來修飾量子點表面。結果顯示改質後的回收率及量子效率(quantum yield)，以磷脂質改質後的量子點回收率最好，約有80%，但發光效率則以MPA的量子點最好，約200%。量子點改質後的鹽穩定度在生理環境100~200mM的NaCl之下都有很好的穩定度，其中以經過磷脂質改質之量子點最穩定，即使在400mM的NaCl下也不會聚集而沈澱。 將各親水改質的量子點加入角質細胞(keratinocyte)及纖維母細胞(fibroblast)的培養基中，發現角質細胞能夠攝取量子點，而纖維母細胞則完全不會。因此，吾人以兩性高分子改質之量子點，在其表面共價鍵結上纖維母細胞生長因子(bFGF)、或Anti-FGF receptor，來標定纖維母細胞表面之生長因子接受器。實驗發現，鍵結上Antibody的量子點在吸附上細胞表面之bFGF受體後能夠進入纖維母細胞內，而鍵結上bFGF的量子點則僅是吸附在細胞的表面。 此結果顯示，不同細胞對量子點的吞噬喜好不同。會被細胞吞噬之量子點可用來進行活細胞內部的染色，不會被細胞吞噬的量子點則可用來偵測細胞膜上的受器。此外，針對同樣的細胞接受器，不同的親和因子也會造成不同的結果，接上bFGF之量子點不會被纖維母細胞吞噬，而接上bFGF受器之抗體的量子點則極易被細胞吞噬。 The major purposes of this study are to investigate the alternation of fluorescent properties, the salt enduribility in physiological environment and the effects of endocytosis of various animal cells after different water soluble treatments of semiconductor nanocrystals CdSe/ZnS core/shell quantum dots (QDs). This work begun with comparing the QDs mass recoveries, relative quantum yields, and salt stabilities in salt-containing buffers after surfaces modification with mercapto-carbonic acids including mercaptopropionic acid (MPA) and mercapto-undecanoic acid (MUA), amphiphilic polymer, poly(maleic anhydride alt-1-tetradecene) (PMATD) and phospholipids, (1,2-disteraroyl-sn-glycero-3-phospho- ethanolamine-N-[amino(polyethylene glycol)2000])(DSPE-PEG). It was found that the phospholipids encapsulated water-soluble QDs revealed highest mass recovery about 80 % and MPA treated QDs had greatest relative quantum yield up to 200 %. And these modified QDs displayed remarkable salt stabilities at the physiological environment like 100 mM to 200 mM NaCl contained solutions. It was deserve to be mentioned that the phospholipids-encapsulated QDs showed the best salt enduriblity without any observable agglomeration, even though the NaCl concentration was raised up to 400 mM. In the following, the water-soluble QDs with various surface modification were co-cultured with Human foreskin fibroblast and keratinocyte, CCD 1106 KERTr., in order to realized the endocytosis process of QDs into the animal cells. Our results showed that the keratinocytes could be easily targeted by water-soluble QDs, however, QDs could not be uptake by fibroblast. Therefore, recombinant human fibroblast growth factor-basic (b-FGF) and monoclonal mouse anti-FGF receptor (anti-FGF receptor) were covalently conjugated to PMATD-encapsulated QDs in the presence of activation reagents. Our results demonstrated that the anti-FGF receptor conjugated QDs were uptaked into the fibroblast after the incubation of receptor-labeled QDs and fibroblasts, furthermore, the b-FGF bound QDs could attach to the FGF receptors located at fibroblast cell surfaces. As mentioned above, different uptaking behaviors of fibroblasts and keratinocytes were exhibition toward the same surface-treated QDs, and the features allowed us for generally labeling or staining of living cells with QDs which could be uptake inside the cells, or allowed us for specifically labeling a cellular target on cell surfaces with QDs which could not be uptake inside the cells. |
