The geometry of nanoparticles plays an important role in their performance as drug carriers. However, the pH-triggered geometrical shape switching of a cationic peptide consisting of isoleucine and lysine is seldom reported. In this work, we designed a cationic peptide with acid reactivity that can be loaded with the poorly soluble antitumor drug (doxorubicin (DOX)) to enhance tumor cell uptake and drug delivery. In a weakly acidic environment, a large portion of random coil structures formed, which subsequently led to nanoparticle destruction and rapid DOX release. In vitro studies demonstrated that this cationic peptide exhibits low toxicity to normal cells. The amount of DOX-encapsulating peptide nanoparticles taken up by tumor cells was greater than that taken up by normal cells. Our results indicated that the use of a weakly acidic microenvironment to induce geometric shape switching in drug-loaded peptide nanoparticles should be a promising strategy for antitumor drug delivery.

中文翻译：

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pH触发的阳离子肽纳米颗粒的几何形状转换，用于细胞摄取和药物递送。

纳米颗粒的几何形状在其作为药物载体的性能中起着重要作用。然而，很少报道由异亮氨酸和赖氨酸组成的阳离子肽的pH触发的几何形状转换。在这项工作中，我们设计了一种具有酸反应性的阳离子肽，可与难溶性抗肿瘤药（阿霉素（DOX））一起加载，以增强肿瘤细胞的吸收和药物递送。在弱酸性环境中，形成了大量的无规卷曲结构，随后导致纳米颗粒破坏和DOX快速释放。体外研究表明，这种阳离子肽对正常细胞的毒性低。肿瘤细胞摄取的包裹DOX的肽纳米颗粒的数量大于正常细胞摄取的数量。