Lipid nanoparticle size, controlled by microfluidic flow rate, shaped mRNA expression and organ distribution.
Evidence
This formulation and delivery experiment used CFD-guided to make 30-270 nm with identical lipid ratios, then tested physicochemical properties, HeLa-cell uptake and transfection, and mouse expression after intravenous and intramuscular dosing.
Caveat
The biological results come from cell and in vivo delivery models, so they do not establish clinical efficacy or safety for mRNA therapies.
Simplified
The emergence of mRNA-containing (LNPs) during the COVID-19 pandemic has revolutionized vaccine technology and is now being explored for protein replacement therapies. This study aimed to test the hypothesis that LNP size, independent of lipid composition, critically influences their physicochemical and biological performance. To achieve this, we employed computational fluid dynamics (CFD) simulations to predict the mixing index within a microfluidic channel, identifying the flow rate conditions at which a 70% mixing index was reached. By tuning the flow rate accordingly, we generated LNPs across a controlled size range of 30-270 nm while maintaining identical lipid ratios. We systematically characterized these LNPs for zeta potential, pKa, generalized polarization, and hemolytic activity. Cellular studies in HeLa cells revealed that smaller LNPs exhibited higher uptake and transfection efficiency, which was quantitatively explained using a mathematical model of cellular uptake. In vivo studies further demonstrated that LNP size affected both the magnitude of mRNA expression and the biodistribution across organs following intravenous and intramuscular administration. Our findings demonstrate precise flow rate-induced size control of LNPs via and reveal that smaller LNPs achieve superior gene expression in vitro and exhibit preferential transfection in vivo, underscoring the importance of size as a design parameter for mRNA delivery systems.
Key numbers
2.5×
Higher Uptake Efficiency
Uptake efficiency of smaller vs. larger in .
30–270 nm
Size Range of
Controlled size range of produced using .
>10
Spleen-to-Liver Ratio
Spleen-to-liver ratio for larger post-intravenous injection.
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