A New Paradigm in Nanomedicine: can structural interiors of nanoparticles regulate cellular delivery?

对医学最有希望的工程贡献之一是纳米药物的开发 健康组织看不见的胶囊，但专门用于攻击患病部位。在过去的10年里 多年来，纳米医学经历了大量新的机会，将治疗扩展到不可药物的蛋白质 随着发现传递到细胞质的小的外源RNA片段能够部署关闭 特定的基因。我们现在能够制作短的(19-21bp)RNA序列，原则上可以关闭任何 但在找到有效的运输工具之前，这项技术都没有用。RNAi疗法是 目前正在经历复兴，这是由于以下方面的效率和生存能力的显著改善 寡核苷酸化学操作和/或通过将其包装成纳米级载体，但目前有 没有FDA批准的用于人类应用的系统。下一代siRNA载体的设计 需要深入了解纳米颗粒的物理化学性质如何真正赋予生物 稳中求进，提高工作效率。例如，我们现在知道，纳米颗粒需要在空间上稳定才能 以满足足够的生物分布特征。然而，siRNA载体设计的中心障碍仍然是 细胞水平。通常情况下，携带rna的颗粒会通过内吞作用穿透细胞，并停留在细胞内直到 腐烂。在这项工作中，我们将强调这样一个事实，内小体的破坏包括 需要大量弹性能量的膜转换(例如，孔洞形成)。除了……之外 表面化学、纳米颗粒的大小和形状被确定为相关的控制参数 细胞摄取。在这项工作中，我们提出了纳米颗粒结构内部是一种新的调控手柄 内体逃逸。脂质纳米粒(LNP)是一种很有前途的siRNA传递载体 然而，几乎所有的研究都局限于使用脂质体制剂的概念。在这项工作中，我们将灌输 纳米粒子内部由高度有序的膜网络组成的LNP设计的新方向 高表面积体积比和固有的膜特性容易破坏内体膜 以最低的能源成本。我们将对组合后的纳米颗粒进行仔细的结构表征 通过对多种细胞系的siRNA传递和基因敲除的定量功能研究，包括 已知难以转化的神经元和干细胞。我们的目标是巩固两者之间的关联 纳米粒子内部结构具有动态的siRNA细胞递送过程，并使下一步 高效RNAi纳米药物的产生。

One of the most promising engineering contributions to medicine is the development of nanoscale drug capsules that are invisible to healthy tissue while specifically directed to attack a diseased site. In the last 10 years, nanomedicine has experienced a surge of new opportunities expanding therapy to undrugable proteins with the discovery that small exogenous RNA bits delivered to the cytoplasm are able to deploy the shutdown of specific genes. We are now able to make short (19-21 bp) RNA sequences that can in principle turn off any given gene but none of this technology is useful until an efficient delivery vehicle is identified. RNAi therapy is currently experiencing a revival due to remarkable improvements in efficacy and viability through oligonucleotide chemical manipulations and/or via their packaging into nano-scale carriers but at present there is no FDA approved system for the application in humans. The design of the next generation of siRNA carriers requires a deep understanding of how nanoparticle's physicochemical properties truly impart biological stability and efficiency. For example, we now know that nanoparticles need to be sterically stabilized in order to meet adequate biodistribution profiles. However, the central hurdle in siRNA carrier design remains at the cellular level. Typically, an RNA-carrying particle will penetrate the cell via endocytosis and rest trapped until decomposition. In this work we will highlight the fact that the disruption of endosomes encompasses membrane transformations (for example pore formation) that cost significant elastic energy. In addition to surface chemistry, nanoparticle size and shape have been identified as relevant parameters controlling cellular uptake. In this work we propose that nanoparticle structural interiors are a novel handle to regulate endosomal escape. Lipid nanoparticles (LNP) have been long recognized as promising siRNA delivery vectors however virtually all studies are locked to the concept of using liposome formulations. In this work we will instill a new direction of LNP design where nanoparticle interiors comprise highly ordered networks of membranes with high surface-to-volume ratios and intrinsic membrane properties prone to disrupt endosomal membranes at minimal energetic cost. We will employ careful structural characterization of the nanoparticles combined with quantitative functional studies of siRNA delivery and gene knockdown to a variety of cell lines, including neurons and stem cells that are known to be hard to transfect. It is our goal to underpin the correlation between nanoparticle internal structures with the dynamic process of siRNA cellular delivery and enable the next generation of highly efficient RNAi nanomedicine.