Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, Oregon 97201, United States.
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon 97201, United States.
Nano Lett. 2020 Jun 10;20(6):4543-4549. doi: 10.1021/acs.nanolett.0c01386. Epub 2020 May 12.
Lipid nanoparticle (LNP) packaged mRNA vaccines have been deployed against infectious diseases such as COVID-19, yet their structural features remain unclear. Cholesterol, a major constituent within LNPs, contributes to their morphology that influences gene delivery. Herein, we examine the structure of LNPs containing cholesterol derivatives using electron microscopy, differential scanning calorimetry, and membrane fluidity assays. LNPs formulated with C24 alkyl derivatives of cholesterol show a polymorphic shape and various degrees of multilamellarity and lipid partitioning, likely due to phase separation. The addition of methyl and ethyl groups to the C24 alkyl tail of the cholesterol backbone induces multilamellarity (>50% increase compared to cholesterol), while the addition of a double bond induces lipid partitioning (>90% increase compared to cholesterol). LNPs with multilamellar and faceted structures, as well as a lamellar lipid phase, showed higher gene transfection. Unraveling the structure of mRNA-LNPs can enable their rational design toward enhanced gene delivery.
脂质纳米颗粒（LNP）包裹的 mRNA 疫苗已被用于对抗 COVID-19 等传染病，但它们的结构特征仍不清楚。胆固醇是 LNPs 的主要成分之一，它有助于其形态的形成，从而影响基因传递。本文使用电子显微镜、差示扫描量热法和膜流动性测定法研究了含有胆固醇衍生物的 LNPs 的结构。用胆固醇的 C24 烷基衍生物制备的 LNPs 表现出多晶型形状和不同程度的多层性和脂质分配，可能是由于相分离所致。在胆固醇主链的 C24 烷基尾端添加甲基和乙基基团会诱导多层性（与胆固醇相比增加超过 50%），而添加双键会诱导脂质分配（与胆固醇相比增加超过 90%）。具有多层和有面结构以及层状脂质相的 LNPs 显示出更高的基因转染效率。揭示 mRNA-LNP 的结构可以实现其合理设计，以增强基因传递。
