文献：Acid-Induced In Vivo Assembly of Gold Nanoparticles for Enhanced Photoacoustic Imaging-Guided Photothermal Therapy of Tumors

文献链接：https://www.medsci.cn/sci/show_paper.asp?id=347451235953a871

作者：Ruili Zhang, Linlin Wang, Xiaofei Wang, Qian Jia, Zhuang Chen, Zuo Yang, Renchuan Ji,Jie Tian, and Zhongliang Wang

相关产品：HS-PEG2000（巯基-聚乙二醇2000）

原文摘要：

   The complexity of biological systems poses a great challenge in the development of nanotheranostic agents with enhanced therapeutic efficacies.To systematically overcome a series of barriers during in vivo administration and achieve optimal antitumor activity, nanotheranostic agents that can self-adaptively change their properties in response to certain tumor-associated signals are highly preferable. Herein, gold nanoparticles with a mixed-charge zwitterionic surface (Au-MUA-TMA) is fabricated, which can undergo pH-triggered self-assembly for promoting tumor targeting and improving photoacoustic imaging (PAI)-guided photothermal tumor ablation.In blood and normal tissues, relatively small-sized Au-MUA-TMA can circulate stably, and upon arriving at the tumor sites, they quickly assemble into larger aggregates in an acidic tumor environment to ensure higher tumor accumulation and retention. Furthermore, the absorption band of Au-MUA-TMA can be remarkably shifted to the near-infrared (NIR) region, which effectively activates the photoacoustic (PA) signals of tumors and enhances photothermal therapy (PTT) with minimal side effects. This in vivo self-assembly strategy enables the nanotheranostic agents to better fulfill multiple requirements for in vivo application, thereby attaining advanced performances in cancer diagnosis and treatment.

HS - PEG2000 表示一端为巯基（-HS），分子量约为 2000 的聚乙二醇（PEG）。聚乙二醇部分是由多个乙二醇单元（-CH₂CH₂O -）重复构成的长链结构。巯基位于聚乙二醇链的一端，它是一种具有较高化学活性的官能团。聚乙二醇链赋予了 HS - PEG2000 良好的水溶性。乙二醇单元中的氧原子能够与水分子形成氢键，使其能在水中很好地溶解。巯基是一个非常关键的活性基团。它可以参与多种化学反应。基于HS - PEG2000的性质，该文献介绍Au-MUA-TMA制备流程如下：

图：作用机理

硫醇保护的AuNPs的制备

用HS-PEG在其表面交换柠檬酸配体，制备了PEG保护的AuNPs。通过与两性离子配体（HS-MUA和HS-TMA）交换柠檬酸盐覆盖的AuNPs，获得了带混合电荷的两性离子配体修饰的AuNPs。通过调节HSMUA与HS-TMA的摩尔比，制备了一系列不同表面电荷的两性离子AuNPs。

图：代表性图像

结论：

该文献成功制备出了基于HS - PEG2000合成的具有混合电荷两性离子表面的金纳米颗粒（Au-MUA-TMA）。它可以通过ph触发的自组装来促进tumour靶向和改善光声成像（PAI）引导的光热tumour消融。这种体内自组装策略使纳米化合物能够更好地满足在体内应用的多种要求。