pH超敏感纳米胶束的形状对其细胞摄取效率及肿瘤精确诊断的影响

Impacts of particle shape on cellular uptake and tumor imaging application of ultra-pH sensitive micelles

本文合成了一种pH超敏感聚合物PEG-iPDPA,并分别通过薄膜分散法和溶剂去除法将其制备成蠕虫形胶束和球形胶束,在体外、细胞和活体水平对两种形状胶束的物理化学性质及细胞摄取效率、肿瘤精确诊断等生物学功能进行了研究。在体外水平,主要考察了二者的pH响应性,结果显示,两种形状的制剂pH响应性良好,在连接上荧光探针后,均能够实现100倍以上的荧光信号开关(ON/OFF);流式细胞术和激光共聚焦显微镜的结果显示,细胞摄取两种形状的胶束均呈时间、浓度双依赖性,但细胞摄取球形胶束的量远高于蠕虫形胶束,这也证明了制剂的形状对细胞摄取行为的影响很大;活体成像结果表明,球形胶束对肿瘤的成像效果更好、灵敏度更高,且在肿瘤内具有更高的蓄积量;细胞毒实验和H&E染色实验显示,两种形状制剂的生物安全性良好。结果说明,球形胶束的生物学性质要优于蠕虫形胶束,其在细胞摄取、生物分布和肿瘤检测等方面都更具有优势。

This study was designed to investigate the impacts of particle shape of micelles on cell uptake and tumor imaging applications. We designed and synthesized an ultra-pH sensitive PEG-iPDPA diblock polymer, and prepared it into wormlike micelles and spherical micelles by thin-film dispersion method and modified solvent evaporation method, respectively. Firstly, the pH responsiveness of two kinds of micelles was investigated in vitro. Both forms of micelles responded to pH sensitively, and each of them could reach 100 times of ON/OFF fold after conjugated with BDP fluorescent probe. Moreover, the cellular uptake of two forms of micelles depended on the concentration and incubation time. However, the amount of cellular uptake of spherical micelles was much higher than that of the wormlike micelles, which proved that the shape of nanoparticles had a great influence on the cellular uptake. The results of in vivo imaging revealed that the spherical micelles had a better tumor accumulation as well as tumor imaging outcomes. Finally, the biosafety of micelles was tested by MTT assay and H＆E staining, which indicated that none of the two kinds of micelles had obvious toxicity. Collectively, these results suggest that the spherical micelles could be a better carrier compared with worm-like micelles in terms of cellular uptake, tumor accumulation and tumor detection.