以mPEG-Ala-Lys自組裝形成之酸鹼敏感型胺基酸交聯微胞作為阿黴素(DOX)傳遞系統之應用

pH-sensitive Self-assembled Crosslinked Polypeptide Micelle for Doxorubicin Delivery

鄭庭璞(Ting-Pu Cheng)

指導教授 ： 朱一民

國立清華大學/工學院/化學工程學系/碩士(2020年)

摘要

生物可降解的奈米微胞作為藥物載體可以有效地將藥物輸送到目標部位，從而增加治療效果，同時最大程度地減少副作用，因此在學術界被廣泛重視。而使用肽鍵鍵結形成的聚胺基酸高分子材料具有良好的生物相容性及生物可分解性質。
阿黴素(DOX)為目前臨床應用廣泛的抗癌藥物，但卻對心肌細胞有害，因此設計奈米微胞作為藥物載體將阿黴素包覆其中從而降低其副作用。
本研究以mPEG-P(Ala)-P(Lys)和mPEG-P(Ala)-P(Asp)做為奈米微胞的藥物載體，藉由NMR與GPC分析高分子的結構與分子量證實合成成功。兩親性團聯共聚物在水中能自組裝形成微胞，製程方便快速。親水端選擇methoxy poly(ethyl glycol) (mPEG)是因其在體內具有優秀的隱匿性，可避免藥物太快被排除掉；而疏水端以聚丙胺酸(Ala)為主，尾端再分別以離胺酸(Lys)和天門冬胺酸(Asp)來進行修飾，此結構在體內降解後的產物為胺基酸分子，對人體細胞毒性極小，且尾端修飾的離胺酸(Lys)和天門冬胺酸(Asp)使其具有pH敏感特性，可做為癌症藥物釋放載體。根據其粒徑大小對酸鹼敏感的變化來看，本研究選擇mPEG-P(Ala)-P(Lys)作為後續的藥物包覆實驗高分子。
為了提高微胞穩定性，選擇戊二醛作為氨基交聯劑，使微胞結構更加穩定，而0.2 wt%的交聯濃度的微胞可得到最大包覆度。在最佳經濟效益的製程下，藥物包覆度為3.07 wt%，藥物包覆效率可達8.19 wt%。微胞粒徑可在水中穩定維持至少五天，大小約為300 nm。
體外藥物釋放結果顯示，DOX-loaded NPs可在酸性環境中有效釋放，同時減少在中性環境下的釋放。而體外細胞毒性測試顯示DOX-loaded NPs具有良好的癌細胞毒殺能力。因此，使用mPEG-P(Ala)-P(Lys)交聯微胞作為DOX包覆載體來進行癌症治療具有其優勢與良好發展潛力。

關鍵字

酸鹼敏感胺基酸微胞 ； 藥物釋放 ； 阿黴素 ； DOX ； 癌症治療

並列摘要

Biodegradable nanoparticles are widely used as a drug carrier to effectively deliver drugs to target sites, thereby increasing the therapeutic effect while minimizing side effects. The polyamide polymer material formed by the peptide bond bonding has good biocompatibility and biodegradable properties.
Doxorubicin is a widely used anticancer drug in clinical practice, but it is harmful to cardiomyocytes. Therefore, nanoparticles are designed to use as a drug carrier to encapsulate doxorubicin and reduce its side effects.
In this study, mPEG-P(Ala)-P(Lys) and mPEG-P(Ala)-P(Asp) were used as drug carriers for nanoparticles. The structure and molecular weight of the polymer were confirmed by NMR and GPC. The amphiphilic copolymer can self-assemble to become micelles in water, and the process is convenient and rapid. Choose methoxy poly(ethyl glycol) (mPEG) as hydrophilic chain because of it excellent hidden property in the body, which can prevent the drug from being eliminated too quickly; while the hydrophobic chain is mainly composed of poly-alanine (Ala), and the tail ends are respectively modified by lysine (Lys) and aspartic acid (Asp). The structure of hydrophilic chain after degradation in vivo will become amino acid, which has minimal cytotoxicity to human cells, and the tail-modified lysine (Lys) and aspartic acid (Asp) make it sensitive to pH and can be used as a carrier for cancer drug release. According to the change of of the particle size to pH environment , mPEG-P(Ala)-P(Lys) was selected as the subsequent drug encapsulation experiment.
In order to improve the stability of micelles, glutaraldehyde was selected as the amino crosslinking agent to make micelles structure more stable, and the 0.2 wt% crosslinker concentration can get the maximum drug capacity. Under the process with the best economic benefit, the drug capacity is 3.07 wt%, and the drug efficiency can reach 8.19 wt%. The micelles size can be kept stable in water for at least five days, and the size is about 300 nm.
In vitro drug release shows that DOX-loaded NPs can be effectively released in an acidic environment, while reducing the release in a neutral environment. In vitro cytotoxicity tests show that DOX-loaded NPs have good cancer cell cytotoxicity. Therefore, using mPEG-P(Ala)-P(Lys) crosslinked micelles as a DOX encapsulation carrier for cancer treatment has its advantages and good development potential.

並列關鍵字

pH-sensitive polypeptide micelle ； drug release ； Doxorubicin ； cancer treatment

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