Induction of Bleb Structures in Lipid Nanoparticle Formulations of mRNA Leads to Improved Transfection Potency

• Published in: Advanced materials (Weinheim) Vol. 35; no. 31; pp. e2303370 - n/a
• Main Authors: Cheng, Miffy Hok Yan, Leung, Jerry, Zhang, Yao, Strong, Colton, Basha, Genc, Momeni, Arash, Chen, Yihang, Jan, Eric, Abdolahzadeh, Amir, Wang, Xinying, Kulkarni, Jayesh A., Witzigmann, Dominik, Cullis, Pieter R.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2023
• Subjects: bleb structures; Buffers; Integrity; lipid nanoparticles; Lipids; Lipids - chemistry; Materials science; mRNA delivery; Nanoparticles; Nanoparticles - chemistry; Optimization; phase separation; RNA, Messenger; RNA, Small Interfering - chemistry; Sodium Citrate; Transfection; bleb structures; lipid nanoparticles; phase separation; mRNA delivery
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202303370

The transfection potency of lipid nanoparticle (LNP) mRNA systems is critically dependent on the ionizable cationic lipid component. LNP mRNA systems composed of optimized ionizable lipids often display distinctive mRNA‐rich “bleb” structures. Here, it is shown that such structures can also be induced for LNPs containing nominally less active ionizable lipids by formulating them in the presence of high concentrations of pH 4 buffers such as sodium citrate, leading to improved transfection potencies both in vitro and in vivo. Induction of bleb structure and improved potency is dependent on the type of pH 4 buffer employed, with LNP mRNA systems prepared using 300 mm sodium citrate buffer displaying maximum transfection. The improved transfection potencies of LNP mRNA systems displaying bleb structure can be attributed, at least in part, to enhanced integrity of the encapsulated mRNA. It is concluded that enhanced transfection can be achieved by optimizing formulation parameters to improve mRNA stability and that optimization of ionizable lipids to achieve enhanced potency may well lead to improvements in mRNA integrity through formation of the bleb structure rather than enhanced intracellular delivery. Lipid nanoparticle (LNP) mRNA systems composed of optimized ionizable lipids often display distinctive mRNA‐rich “bleb” structures. In this work, it is shown that such structures can also be induced for LNPs containing nominally less active ionizable lipids by formulating them in the presence of high concentrations of pH 4 buffer, leading to dramatically improved transfection potencies both in vitro and in vivo.