Small metallic nanoparticles are proposed as potential nanodrugs to optimize the performances of radiotherapy. This strategy, based on the enrichment of tumours with nanoparticles to amplify radiation effects in the tumour, aims at increasing the cytopathic effect in tumours while healthy tissue is preserved, an important challenge in radiotherapy. Another major cause of radiotherapy failure is the radioresistance of certain cancers. Surprisingly, the use of nanoparticles to overcome radioresistance has not, to the best of our knowledge, been extensively investigated. The mechanisms of radioresistance have been extensively studied using Deinococcus radiodurans, the most radioresistant organism ever reported, as a model. In this work, we investigated the impact of ultra-small platinum nanoparticles (1.7 nm) on this organism, including uptake, toxicity, and effects on radiation responses. We showed that the nanoparticles penetrate D. radiodurans cells, despite the 150 nm cell wall thickness with a minimal inhibition concentration on the order of 4.8 mg L−1. We also found that the nanoparticles amplify gamma ray radiation effects by >40%. Finally, this study demonstrates the capacity of metallic nanoparticles to amplify radiation in radioresistant organisms, thus opening the perspective to use nanoparticles not only to improve tumour targeting but also to overcome radioresistance.

中文翻译：

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铂纳米粒子：克服辐射抗性的精美工具。

小金属纳米粒子被提议作为潜在的纳米药物来优化放射治疗的性能。这种策略基于用纳米颗粒富集肿瘤以放大肿瘤中的辐射效应，旨在增加肿瘤中的细胞病变效应，同时保留健康组织，这是放射治疗的一个重要挑战。放射治疗失败的另一个主要原因是某些癌症的放射抗性。令人惊讶的是，据我们所知，尚未对使用纳米粒子来克服辐射抗性进行广泛研究。使用迄今为止报道的最具抗辐射性的生物体耐辐射异常球菌作为模型，已经对辐射抗性的机制进行了广泛研究。在这项工作中，我们研究了超小铂纳米粒子（1.7 nm）对这种生物体的影响，包括摄取、毒性和对辐射反应的影响。我们发现，尽管细胞壁厚度为 150 nm，且最小抑制浓度约为 4.8 mg L-1，但纳米颗粒仍能穿透 D.radiurans 细胞。我们还发现纳米粒子将伽马射线辐射效应放大了 >40%。最后，这项研究证明了金属纳米粒子在抗辐射生物体中放大辐射的能力，从而为使用纳米粒子不仅改善肿瘤靶向性而且克服辐射抗性开辟了前景。