開發具磁性與酸鹼應答性複合高分子液胞作為腫瘤標的藥物傳遞及MR影像顯影之診斷治療奈米平台

Magnetic and pH-Responsive Complex Polymeric Vesicles as a Theranostic Nanoplatform for Tumor-Targeting Drug Delivery and Enhanced MR Imaging

施宗甫

指導教授 ： 邱信程

國立清華大學/原子科學院/生醫工程與環境科學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00015

摘要

為了在醫學上達到有效診斷與治療的效用，本研究開發出具磁性與酸鹼應答性高分子複合液胞作為攜帶治療藥劑和MR影像顯影劑之傳遞載體。於pH 5.0含有citrate-SPIO的水相中藉由高分子PAAc-co-DSA的自組裝行為形成奈米級SPIO-loaded 高分子液胞(ca. 110 nm)。DOX分子以靜電作用力吸附於液胞表面富含AAc鏈段的區域；其包覆效率約為70 %。為了提高結構的穩定性和具有主動腫瘤標的能力，藉由靜電作用力將高分子chitosan和γ-PGA(OSu)-g-PEG-folate以layer-by-layer的方式吸附於液胞表面，最後形成FA-conjugated SPIO/DOX-loaded高分子複合液胞(ca. 220 nm)。於MR影像顯影方面，SPIO-loaded 複合液胞具有較高的橫向鬆弛率r2 (i.e., 255 Fe mM-1 S-1 vs 183.4 Fe mM-1 S-1 of Resovist)相較於商品化顯影劑Resovist。在藥物釋放行為方面主要和環境的pH值有關；於10小時左右，來自SPIO/DOX-loaded複合液胞之藥物分子DOX的累積釋放量於pH 4.7和pH 7.4分別為70 %和20 %。另一方面，利用CLSM和流式細胞儀的分析結果得知表面修飾葉酸分子之高分子複合液胞有助於細胞(HeLa cells)以folate receptor-mediated的吞噬路徑進行uptake。於細胞(HeLa cells)毒性的結果顯示，FA-conjugated SPIO/DOX-loaded高分子複合液胞對HeLa cells的毒殺效果比folate-free SPIO/DOX-loaded高分子複合液胞來的好。最後，此多功能FA-conjugated SPIO/DOX-loaded高分子複合液胞具腫瘤標的藥物傳遞、藥物控制釋放能力及MR 影像顯影功能，可作為腫瘤標的藥物傳遞及MR影像診斷奈米平台。

關鍵字

高分子液胞 ； 藥物刺激控制釋放 ； 腫瘤標的

並列摘要

In this study, a multifunctional and pH-responsive polymeric complex vesicle as an anticancer drug and MRI contrast agent carrier has been developed for cancer theranostics. The superparamagnetic iron oxide (SPIO)-loaded polymeric vesicles (ca. 110 nm) were formed by self-assembly of the poly(acrylic acid-co-disterin acrylate) (P(AAc-co-DSA)) in the SPIO aqueous solution (pH 5.0) via sonication technique while the SPIO was simultaneously encapulated into the interior aqueous compartment of the vesicles. The anticancer drug, doxorubicin (DOX), was then loaded within ionized AAc-rich regions of the membrane of polymer vesicle via electrostatic interaction between the ionized AAc units and postively charged DOX molecules. To improve the stability of the resulting polymer vesicles, chitosan and folate-polyethylene glycol-grafted poly(glutamic acid) (PGA-g-PEG(FA)) were sequentially deposited on the outermost surfaces of the DOX/SPIO-loaded polymer vesicles. The loading efficiency of DOX was ca. 70 %. The in vitro drug release behavior of SPIO/DOX-loaded complex vesicles shows a significant increased drug release at pH 4.7 (70%) and a severely retarded drug release at pH 7.4 (20%). This indicates that the loaded DOX molecules can be effectivitly released in the acid environment of tumor (e.g. endosomes or lysosomes). Compared to commercial MRI contrast agent, Resovist, the relaxivity r2 value of SPIO/DOX-loaded polymeric complex vesicles was much higher than Resovist. Results from flow cytometry and confocal laser scanning microscopy (CLSM) analysis showed that folate-conjugated vesicles exhibited higher than folat-free vesicles which also led to higher cytotoxicity. Thus, these DOX/SPIO-loaded folate-conjugated polymer complex vesicles can provide pH-controlled drug release, as well as enhanced MRI contrast, thereby mtargeted cancer therapy and diagnosis possible.

並列關鍵字

polymersomes ； stimuli-triggered drug release ； tumor-targeting

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