高分子奈米粒子於生物醫學之應用：磁振造影、藥物輸送與細胞檢測

Abstract

近年來，高分子奈米粒子由於其多樣化的表面官能基以及良好的生物相容性，被廣泛的研究並發展為藥物載體、顯影劑與生物感測器。在本研究中，成功利用間苯二胺製備出能夠攜帶大量螢光分子的奈米球。此奈米球不但具有非常均勻的尺寸與良好的光穩定性，其螢光強度對於酸性環境亦非常靈敏。經高解析顯微鏡進行結構鑑定，與追蹤單粒子放光過程後，已成功的建立「逆自消光」的螢光機制，並可作為細胞內的酸感測器。 此高分子奈米球進一步的發展為一體成型的核殼高分子球狀結構。本研究將釓離子結合在結構核心，並以酸性靈敏的殼層裝載抗癌藥物小紅黴，成功的發展出具有磁振造影與藥物輸送功能之奈米粒子。此奈米粒子可以選擇性的進行藥物釋放（其釋放效率在pH值7.4和5.5之間有75％的差異）和磁振造影（其弛豫值在pH值7.4和5.5時依序為0.9和14.5 mM-1 s-1）。在小鼠實驗中，由於高滲透滯留效應與酸控制釋放策略，此奈米粒子之腫瘤抑制效果顯著優於小紅黴。這是目前最簡便的診斷與治療複合粒子之製備方法。 最後，本研究以高分子球裝載玫瑰紅6G和玫瑰紅101，結合細胞靶向適合體sgc8c及TD05，進行CCRF-CEM和Ramos細胞的檢測。當探針辨識和進入標的細胞後，將透過逆自消光機制產生螢光訊號。我們可透過螢光強度進行細胞定量分析，同時利用螢光顏色作為細胞種類鑑定。透過流式細胞技術，CCRF-CEM和Ramos細胞的偵測極限分別可達到80和221顆。此方法成功的簡化了偵測的步驟，並具有發展為疾病快篩的潛力。

In recent years, polymeric nanoparticles (NPs) have been widely studied and developed for drug and gene carriers, medical imaging and biosensors because of their excellent biocompatibility, biodegradability. We used 1,3-phenylenediamine as a precursor to prepare nanospheres (DARs) and encapsulated with high concentration of fluorophores. The nanosphere is monodispersed, photo-stable, and the fluorescent intensity is sensitive to the pH values. The particles were characterized using super resolution microscope, and the fluorescent enhancement were tracked through single-particle technology. The mechanism called “retro-self-quench” has been established. Based on the understanding of DARs, we provide an innovative platform, termed unibody core-shell (UCS), for preparation a theranostic NPs. UCS is comprised of two covalent-bonded polymers differed only by the functional groups at the core and the shell. By conjugating Gd3+ at the stable core and encapsulating doxorubicin (Dox) at the shell in a pH-sensitive manner, we developed a theranostic NPs (UCS-Gd-Dox) that achieved a selective drug release (75% difference between pH 7.4 and 5.5) and MR imaging (r1 = 0.9 and 14.5 mM-1 s-1 at pH 7.4 and 5.5, respectively). The anti-cancer effect of UCS-Gd-Dox is significantly better than free Dox in tumor-bearing mouse models, presumably due to enhanced permeability and retention effect and pH-triggered release. To the best of our knowledge, this is the simplest approach to obtain the theranostic NPs with Gd-conjugation and Dox doping. Since the amine-rich surface of DARs are ready for functionalization, DARs loaded with Rhodamine 6G (R6GDAR) and Rhodamine 101 (R101DAR) are conjugated with aptamer sgc8c and TD05 for the detection of CCRF-CEM and Ramos cells, respectively. The concentrated fluorophores released from DARs into the cells when they taken by targeted cells, thus generate strong fluorescence and “light up” the cells. This strategy could not only rapidly recognize and quantify the target CCRF-CEM/Ramos cells with a microplate reader, but also has a remarkable detection limit as low as 80 and 221 for CCRF-CEM and Ramos cells using flow cytometry, respectively. This approach significantly simplifies the detection procedures, therefore have great potential for rapid screening.