Various nanoparticles have been developed for tumor-targeted drug delivery. However, nanoparticles with effective targeting and intelligent release capacity are still deficient. Herein, we present new pH-responsive and neutral charged nanoparticles for tumor-targeted anticancer drug delivery. Oxidized starch was synthesized and simultaneously modified by cholesterol and imidazole to obtain amphiphilic cholesterol/imidazole modified oxidized-starch (Cho-Imi-OS). Cho-Imi-OS easily self-assembled into nanoparticles by dialysis. Curcumin was selected as model drug to be encapsulated into the hydrophobic core of nanoparticles. The results showed that curcumin would effectively accumulate in cancer cells by encapsulating into the nanoparticles owing to the nano-sized structure and near neutral charged property of nanoparticles. Curcumin was released faster at pH 5.5 than that at pH 7.4 from the curcumin-loaded nanoparticles (Cur-NPs), indicating the pH-triggered release capacity of Cur-NPs after endocytosis by endosomes since the pH is low to 5.0∼6.0 in endosomes. Naturally, Cur-NPs showed significantly strong inhibitory effect on cancer cells.

中文翻译：

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基于胆固醇/咪唑修饰的氧化淀粉的pH响应纳米颗粒，用于靶向抗癌药物的递送。

已经开发出各种纳米颗粒用于靶向肿瘤的药物递送。然而，具有有效靶向和智能释放能力的纳米颗粒仍然不足。在这里，我们提出了新的pH响应和中性带电纳米粒子用于肿瘤靶向的抗癌药物传递。合成氧化淀粉，并同时用胆固醇和咪唑改性，得到两亲性胆固醇/咪唑改性的氧化淀粉（Cho-Imi-OS）。Cho-Imi-OS易于通过透析自组装成纳米颗粒。选择姜黄素作为模型药物，将其封装在纳米颗粒的疏水核中。结果表明，由于纳米粒子的纳米尺寸结构和接近中性的带电特性，姜黄素可通过包封到纳米粒子中而有效地在癌细胞中积累。姜黄素在pH 5.5下比载有姜黄素的纳米颗粒（Cur-NPs）在pH 7.4下释放更快，这表明内体吞噬后Cur-NPs的pH触发释放能力是因为内体的pH低至5.0〜6.0 。自然，Cur-NP对癌细胞具有明显的强抑制作用。