Fig. 6.

A) Cryo-TEM images of LNPs prepared with cholesterol, (adopt a single lipid bilayer structure (left)) and stigamstanol instead of cholesterol (adopt a multilamellar structure (right)). Reprinted (and adapted) with permission from [99]. Copyright 2020 American Chemical Society. B) Structural models of different LNP types carrying mRNA cargo. Reprinted (and adapted) with permission from [99]. Copyright 2020 American Chemical Society. C) Cryo-TEM images of LNPs encapsulating siRNA sandwiched between closely apposed monolayers (left) and LNPs prepared in the absence of siRNA (right). The uncharged ionizable lipids that are not interacting with siRNA can adopt an amorphous oil phase when pH is raised to 7.4. Reprinted (and adapted) with permission from [94]. Copyright 2018 American Chemical Society. D) Structural model of LNP-siRNA showing two distinct phases, including a proposed oil-like phase containing the uncharged ionizable lipids and an aqueous phase. Reprinted (and adapted) with permission from [94]. Copyright 2018 American Chemical Society.