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

工程学对医学最有前途的贡献之一是纳米级药物的开发 健康组织看不见的胶囊，而专门针对攻击患病部位。在过去10 多年来，纳米医学经历了一波新的机会，将治疗扩展到不可破坏的蛋白质 随着发现小的外源RNA片段被递送到细胞质能够部署关闭， 特定的基因。我们现在能够制造短（19-21 bp）RNA序列，原则上可以关闭任何 但是在鉴定出有效的递送载体之前，这些技术都是无用的。RNAi治疗是 目前正在经历复苏，由于显着改善的效力和可行性， 寡核苷酸化学操作和/或通过它们的包装进入纳米级载体，但目前 FDA还没有批准用于人体的系统。下一代siRNA载体的设计 需要深入了解纳米粒子的物理化学性质如何真正赋予生物学特性。 稳定性和效率。例如，我们现在知道纳米颗粒需要空间稳定， 以满足适当的生物分布特征。然而，siRNA载体设计中的中心障碍仍然在于 细胞水平。通常，携带RNA的颗粒将通过内吞作用穿透细胞并保持捕获，直到细胞被捕获。 分解在这项工作中，我们将强调这样一个事实，即内体的破坏包括 膜转化（例如孔形成）消耗显著的弹性能量。除了 表面化学、纳米颗粒尺寸和形状已被确定为控制纳米颗粒尺寸和形状的相关参数。 细胞摄取在这项工作中，我们提出，纳米颗粒的结构内部是一种新的处理，以调节 内体逃逸脂质纳米粒（Lipid nanoparticles，LNP）是一种很有前途的siRNA载体 然而，实际上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 LNP设计的新方向，其中纳米颗粒内部包含高度有序的膜网络 具有高的表面积与体积比和易于破坏内体膜的内在膜特性 以最小的能量成本。我们将采用仔细的结构表征的纳米粒子组合 通过对siRNA递送和基因敲低到多种细胞系的定量功能研究， 神经元和干细胞是很难被切除的。我们的目标是巩固 纳米颗粒内部结构与siRNA细胞递送的动态过程，并使下一个 产生高效的RNAi纳米药物。

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.