College of Marine Life Science, Ocean University of China, Yushan Road, Qingdao, Shandong Province 266003, China.
College of Food Science and Engineering, Ocean University of China, Yushan Road, Qingdao, Shandong Province 266003, China.
Carbohydr Polym. 2017 Aug 1;169:341-350. doi: 10.1016/j.carbpol.2017.03.090. Epub 2017 Mar 29.
A novel intelligent nanocarrier with pH and redox sensitivities was developed based on Carboxymethyl-chitosan (CMCS) and thioglycolic acid conjugated chitosan (TCS) to provide precise spatiotemporal control for efficient intracellular delivery. Doxorubicin (DOX) loaded nanocarriers (DOX/CMCS-TCS NPs) were simply prepared by ionic gelation and then oxidation crosslink. The nanocarriers exhibited decent stability at pH 7.4 for up to 3days and underwent aggregation under acidic pH (5.5) due to protonation of the carboxyl groups on CMCS. The TCS skeleton was stable at pH 5.5 (mimic endo/lysosomes) but disintegrated in the presence of 10mM glutathione (GSH) at pH 7.4 (mimic cytosol). In vitro DOX release from DOX/CMCS-TCS NPs was enhanced at pH 5.5 compared with physiological condition, with 64.2% and 31.6% DOX released in 2h, respectively. While 85.2% of DOX was released within 2h as treated with 10mM GSH, suggesting the release was closely associated with structural disintegration of nanocarriers. The maximum release of DOX was obtained at 10mM GSH and pH 5.5 with 92.3% of DOX released in 5h. Confocal laser scanning microscopy observation indicated that DOX/CMCS-TCS NPs efficiently escaped from endo/lysosomes within 1h incubation with MCF-7 cells and gave the best performance in delivering DOX into nucleus in 2h. Anticancer activity assay revealed that DOX/CMCS-TCS NPs had comparable or even better inhibition of cell viability at high drug concentrations than free DOX, with the IC of 0.6μg/mL following 48h incubation. In summary, the simply constructed DOX/CMCS-TCS NPs could not only respond to intracellular delivery temporally, they also achieve rapid release spatially in nucleus, which provide a precise spatiotemporal control of drug delivery for cancer therapy.
基于羧甲基壳聚糖（CMCS）和巯基乙酸接枝壳聚糖（TCS），开发了一种具有 pH 和氧化还原双重敏感性的新型智能纳米载体，为高效的细胞内递药提供精确的时空控制。通过离子凝胶化和氧化交联，简单制备了载阿霉素（DOX）的纳米载体（DOX/CMCS-TCS NPs）。纳米载体在 pH 7.4 下稳定长达 3 天，在酸性 pH（5.5）下发生聚集，这是由于 CMCS 上的羧基质子化。TCS 骨架在 pH 5.5（模拟内体/溶酶体）下稳定，但在 pH 7.4 下（模拟细胞质）存在 10mM 谷胱甘肽（GSH）时分解。与生理条件相比，DOX/CMCS-TCS NPs 在 pH 5.5 下的 DOX 释放增强，分别在 2 小时内释放 64.2%和 31.6%的 DOX。而用 10mM GSH 处理时，85.2%的 DOX 在 2 小时内释放，表明释放与纳米载体的结构分解密切相关。在 10mM GSH 和 pH 5.5 下，DOX 的最大释放量为 92.3%，在 5 小时内释放。共聚焦激光扫描显微镜观察表明，DOX/CMCS-TCS NPs 在 MCF-7 细胞孵育 1 小时内能够有效地从内体/溶酶体逃逸，并在 2 小时内将 DOX 递送至细胞核，效果最佳。抗癌活性测定表明，与游离 DOX 相比，高药物浓度下 DOX/CMCS-TCS NPs 对细胞活力的抑制作用相当或更好，孵育 48 小时后 IC 为 0.6μg/mL。总之，构建简单的 DOX/CMCS-TCS NPs 不仅可以在时间上响应细胞内递药，还可以在核内实现快速的空间释放，为癌症治疗提供精确的时空药物递药控制。
