Nanoparticles of heavy elements can be used as radiosensitizers to enhance X-ray radiation therapy, but a major roadblock in translating nanoparticle radiosensitizers into clinical practice of cancer treatment is related to the non-degradable nature of the nanoparticles, which can cause accumulation inside body and long-term toxicity. This paper reports the use of a folate-inserted, red blood cell membrane-modified bismuth (i.e., F-RBC bismuth) nanoparticles in X-ray radiation therapy for breast cancer, where cell membrane coating provides long blood circulation time, folate acts as tumor targeting agent, X-ray and bismuth nanoparticles interaction generates more free radicals for cancer cells damage, and physiological condition helps dissolve bismuth nanoparticles after treatment. Significant tumor inhibition and improved survival ratio in mice was confirmed when F-RBC bismuth nanoparticles were used to sensitize X-ray radiation. In vivo bio-distribution and histological analysis indicated F-RBC bismuth nanoparticles were excreted from animal body after 15 days and no evident damage or inflammatory was observed in major organs. Cell membrane modification and dissolution of bismuth nanoparticles in body allow the fine tune of the circulation, radiation enhancement and body clearance in such a way that treatment effect can be maximized and long term toxicity can be minimized.

中文翻译：

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靶向肿瘤，隐形且可降解的铋纳米粒子，可增强乳腺癌的X射线放射治疗

可以将重元素的纳米粒子用作放射增敏剂，以增强X射线放射疗法，但是将纳米粒子放射增敏剂转化为癌症治疗的临床实践中的主要障碍与纳米粒子的不可降解特性有关，纳米粒子可能导致体内和体内的积累。长期毒性。本文报道了叶酸插入的红细胞膜修饰的铋（即F-RBC铋）纳米粒子在乳腺癌X射线放射治疗中的用途，其中细胞膜涂层可提供较长的血液循环时间，叶酸起着肿瘤靶向剂，X射线和铋纳米粒子的相互作用产生了更多的自由基，可破坏癌细胞，并且生理条件有助于治疗后溶解铋纳米粒子。体内生物分布和组织学分析表明，F-RBC铋纳米颗粒在15天后从动物体内排出，并且在主要器官中未观察到明显的损伤或炎症。铋纳米粒子在体内的细胞膜修饰和溶解可以实现循环的微调，辐射增强和体内清除，从而可以最大程度地提高治疗效果，并使长期毒性最小化。