Imidazolium Lipid-based Nanoparticles Enable Effective mRNA Delivery and Cellular Immune Response

Area of Science:

• Biotechnology
• Nanomedicine
• Immunology

Background:

• Conventional ionizable lipid nanoparticles (LNPs) for nucleic acid delivery are pH-dependent.
• There is a need for alternative LNP systems with improved performance and broader applicability.

Purpose of the Study:

• To develop and screen novel imidazolium LipidBrick® cationic LNPs as a pH-independent alternative for nucleic acid delivery.
• To identify high-performing LNP formulations for enhanced mRNA delivery and immune response induction.

Main Methods:

• High-throughput screening of 1,944 LNP formulations with varying imidazolium cores, helper lipids, and PEG densities.
• In vitro cell-based assays for cellular uptake, endosomal escape, and cytotoxicity.
• In vivo intramuscular administration in mice to assess transgene expression, antibody titers, and T-cell responses.
• Machine-learning analysis to identify formulation design rules.

Main Results:

• Over 50% of the screened LipidBrick® LNPs outperformed the benchmark ALC-0315 in mammalian cell types.
• Top candidates demonstrated robust cellular uptake, efficient endosomal escape, and strong transgene expression.
• A lead formulation (C3 LNP) showed comparable intramuscular expression and antibody titers to ALC-0315, with significantly enhanced T-cell responses and low cytotoxicity.

Conclusions:

• Cationic LipidBrick® LNPs represent a versatile, pH-independent platform for mRNA delivery.
• This platform enables high-throughput discovery of effective ionization-independent systems.
• These LNPs can effectively prime adaptive immune responses, offering a promising strategy for vaccine development.