In this paper, in order to take advantage of the combination between magnetic nano-Fe₃O₄ and surface modifier, a pH-sensitive drug delivery system that could effectively deliver doxorubicin (DOX) to tumor tissue was constructed. The novel drug delivery system named Fe₃O₄-TIPTS-g-(PEI-co-PEG) was prepared through three steps. The first step, a surface modifier with the thiol group, thiohydrazide-iminopropyltriethoxysilane surface modifier (named TIPTS), was synthesized for the first time. The second step, Fe₃O₄-TIPTS was synthesized by treating nano-Fe₃O₄ with TIPTS. The last step, Fe₃O₄-TIPTS-g-(PEI-co-PEG) was synthesized in the presence of the Fe₃O₄-TIPTS, polyethyleneimine (PEI), and polyethylene glycol (PEG) by mercapto-initiated radical polymerization. Among them, magnetic nanoparticles (MNPs) were used as magnetically responsive carriers, PEG was the surface-modifying compound, and PEI was the drug loading site which primary amine reacts with doxorubicin (DOX). Targeted nanoparticles were considerably stabilize in various physiological solutions and exhibited pH-sensitive performance in drug release. Thence, Fe₃O₄-TIPTS-g-(PEI-co-PEG) is a promising nanocarrier for targeting tumor therapy.

中文翻译：

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新型硫醇表面改性剂和Fe3O4载药剂的制备及在pH敏感性下的释放

为了利用磁性纳米Fe ₃ O ₄与表面改性剂的结合，构建了一种pH敏感药物传递系统，该系统可以有效地将阿霉素（DOX）传递至肿瘤组织。通过三个步骤制备了名为Fe ₃ O ₄ -TIPTS-g-（PEI-co-PEG）的新型药物递送系统。第一步，首次合成了具有巯基的表面改性剂，巯基肼-亚氨基丙基三乙氧基硅烷表面改性剂（命名为TIPTS）。第二步，通过用TIPTS处理纳米Fe ₃ O ₄来合成Fe ₃ O ₄ -TIPTS。最后一步，Fe ₃ O ₄在Fe ₃ O ₄ -TIPTS，聚乙烯亚胺（PEI）和聚乙二醇（PEG）的存在下，通过巯基引发的自由基聚合合成-TIPTS-g-（PEI-co-PEG）。其中，磁性纳米颗粒（MNP）被用作磁响应载体，PEG是表面改性化合物，PEI是伯胺与阿霉素（DOX）反应的载药位点。靶向的纳米颗粒在各种生理溶液中具有相当的稳定性，并且在药物释放中表现出pH敏感性能。因此，Fe ₃ O ₄ -TIPTS-g-（PEI-co-PEG）是靶向肿瘤治疗的有前途的纳米载体。