Microfluidic Mixing: A General Method for Encapsulating Macromolecules in Lipid Nanoparticle Systems

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• 作者：Alex K. K. Leung ; Yuen Yi C. Tam ; Sam Chen ; Ismail M. Hafez ; Pieter R. Cullis
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：119
• 期：28
• 页码：8698-8706
• 全文大小：512K
• ISSN：1520-5207

文摘

Previous work has shown that lipid nanoparticles (LNP) composed of an ionizable cationic lipid, a poly(ethylene glycol) (PEG) lipid, distearoylphosphatidylcholine (DSPC), cholesterol, and small interfering RNA (siRNA) can be efficiently manufactured employing microfluidic mixing techniques. Cryo-transmission electron microscopy (cryo-TEM) and molecular simulation studies indicate that these LNP systems exhibit a nanostructured core with periodic aqueous compartments containing siRNA. Here we examine first how the lipid composition influences the structural properties of LNP鈥搒iRNA systems produced by microfluidic mixing and, second, whether the microfluidic mixing technique can be extended to macromolecules larger than siRNA. It is shown that LNP鈥搒iRNA systems can exhibit progressively more bilayer structure as the proportion of bilayer DSPC lipid is increased, suggesting that the core of LNP鈥搒iRNA systems can exhibit a continuum of nanostructures depending on the proportions and structural preferences of component lipids. Second, it is shown that the microfluidic mixing technique can also be extended to encapsulation of much larger negatively charged polymers such mRNA (1.7 kb) or plasmid DNA (6 kb). Finally, as a demonstration of the generality of the microfluidic mixing encapsulation process, it is also demonstrated that negatively charged gold nanoparticles (5 nm diameter) can also be efficiently encapsulated in LNP containing cationic lipids. Interestingly, the nanostructure of these gold-containing LNP reveals a 鈥渃urrant bun鈥?morphology as visualized by cryo-TEM. This structure is fully consistent with LNP鈥搒iRNA structure predicted by molecular modeling.