The hydrophobically modified glycol chitosan (HGC) nanomicelle has received increasing attention as a promising platform for the delivery of chemotherapeutic drugs. To improve the tumor selectivity of HGC, here an avidin and biotin functionalization strategy was applied. The hydrodynamic diameter of the biotin-avidin-functionalized HGC (cy5.5-HGC-B4F) was observed to be 104.7 nm, and the surface charge was +3.1 mV. Confocal and structured illumination microscopy showed that at 0.1 mg/ml, cy5.5-HGC-B4F nanomicelles were distributed throughout the cytoplasm of MDA-MB-231 breast cancer cells after 2 h of exposure without significant cytotoxicity. To better understand the intracellular fate of the nanomicelles, entrapment studies were performed and demonstrated that some cy5.5-HGC-B4F nanomicelles were capable of escaping endocytic vesicles, likely via the proton sponge effect. Quantitative analysis of the movements of endosomes in living cells revealed that the addition of HGC greatly enhanced the motility of endosomal compartments, and the nanomicelles were transported by early and late endosomes from cell periphery to the perinuclear region. Our results validate the importance of using live-cell imaging to quantitatively assess the dynamics and mechanisms underlying the complex endocytic pathways of nanosized drug carriers.

中文翻译：

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生物功能化壳聚糖纳米胶束的设计、表征和细胞内运输


疏水改性乙二醇壳聚糖（HGC）纳米胶束作为化疗药物递送的有前景的平台受到越来越多的关注。为了提高 HGC 的肿瘤选择性，这里应用了抗生物素蛋白和生物素功能化策略。观察到生物素-亲和素功能化的HGC（cy5.5-HGC-B4F）的流体动力学直径为104.7 nm，表面电荷为+3.1 mV。共焦和结构照明显微镜显示，0.1 mg/ml 的 cy5.5-HGC-B4F 纳米胶束在暴露 2 小时后分布在整个 MDA-MB-231 乳腺癌细胞的细胞质中，没有明显的细胞毒性。为了更好地了解纳米胶束的细胞内命运，进行了包埋研究，并证明一些 cy5.5-HGC-B4F 纳米胶束能够逃离内吞囊泡，可能是通过质子海绵效应。对活细胞中内体运动的定量分析表明，HGC的添加大大增强了内体区室的运动性，并且纳米胶束通过早期和晚期内体从细胞外周转运至核周区域。我们的结果验证了使用活细胞成像定量评估纳米药物载体复杂内吞途径的动力学和机制的重要性。