多功能複合型奈米微胞之研發與癌症治療之應用

Investigation of Multifunctional Mixed Micelles and Their Application in Cancer Therapy

黃俊凱(Chun-Kai Huang)

指導教授 ： 薛敬和

國立清華大學/工學院/化學工程學系/碩士(2006年)

摘要

本研究主要以PLA-g-P(NIPAAm-co-MAAc)(Graft)與mPEG-PLA (Block)探討複合型微胞之形成機制， 以不同莫耳比例之Block與Graft形成複合型奈米微胞，並合成三種不同PLA分子量之Block，依Graft與Block之臨界微胞濃度（CMC）的不同，探討其CMC差異性對複合型奈米微胞形成機制之影響，並利用此實驗結果為依據，加入第三種成分FITC-PEG-PLA或Gal-PEG-PLA於複合系統內，研究結果顯示，複合型微胞於形成初期，及水含量較少時，Graft之MAAC與Block之PEG存在氫鍵作用力，但複合型微胞之粒徑大小由個別之CMC所決定，且隨著Block之疏水性鏈段越長越能控制Graft之聚集能力。由於複合型微胞之內核為Graft所組成，因此可用以包覆疏水性抗癌藥物doxorubicin(free base)。經由體外藥物釋放模擬實驗證實複合型藥物微胞於pH7.4及37℃之環境下可以穩定地將藥物包覆，於pH5.0及37℃之環境下，可將藥物釋放出，並呈穩定釋放的效果。以人類子宮頸癌細胞（HeLa cell）與多成分複合型奈米藥物微胞共同進行培養，並以共軛焦顯微鏡觀測藥物及複合型微胞分佈情形，發現其綠光（FITC-mixed micelle）皆累積於細胞質部分，紅光（DOX）皆累積於細胞核部分。並將多成分複合型奈米藥物微胞於4℃下，與HepG2細胞進行培養，其結果發現有明顯抑制細胞生長的效果。

關鍵字

臨界微胞濃度 ； 溫度應答 ； 酸鹼應答 ； 抗癌藥物

並列摘要

The self-assembly of amphiphilic copolymers into micelles in a selective solvent, including diblock copolymers, triblock copolymers and graft copolymers, have attracted much interest. Besides the mono-unimer composition, many investigations dealt with the multicomponent micelles (also called mixed micelles) from the di-diblock copolymer system, the tri-diblock copolymer system or the tri-triblock copolymer system because of their comicellization behavior and their extensive applications in such areas as drug delivery and particle modification.

The novel mixed micelle which was composed of graft copolymer and diblock copolymer is successfully prepared. Poly (N-isopropyl- acrylamide-co-methyl acrylic acid)-g-poly (D,L- lactide) (P(NIPAAm-co-MAAc)-g-PLA ) graft copolymer formed the multifunctional inner core of mixed micelle. PNIPAAm have lower critical solution temperature (LCST) at 32℃ which was below the nominal body temperature is unstable in the blood circulation. By the addition of MAAc in PNIPAAm, the LCST not only raise to above the nominal body, but also stabilize in blood circulation and offer the carboxylic group which can generate hydrogen bond interaction and dissociation at pH＞7.4. The micelle can utilized the pH and thermal response to accumulate at tumor tissue. Because the PLA is the side chain of graft copolymer, the mobility is very slowly so that the critical micelle concentration (CMC) is rarely low.

By addition the diblock copolymer poly(ethylene glycol)-b-poly (D,L-lactide) (PEG-PLA) in to the micelle system, PEG-PLA can avoid the secondary aggregation of graft copolymer because of the hydrophilicity of PEG.. It’s could not only reduce the secondary aggregation but also prolong the circulation time in the blood. In this study, we investigated the effect of mixed micelle with different hydrophobic length of diblock copolymer on comicellization. The results indicate that the stability of mixed micelles increases with the molecular weight of PLA increasing, and the hydrogen bond interaction of PEG and MAAc only occurred at initial aggregation during comicellization. The particle sizes of mixed micelle were ranged from100 to 200 and exhibited the narrow size distribution (PI < 0.1) in all of these cases.

並列關鍵字

CMC ； temperature-response ； pH-response ； anti-cancer drug

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