Lipid Nanoparticles-Mediated mRNA Delivery to the Eye Affected by Ionizable Cationic Lipid

Ionizable lipid serves as the key functional component in lipid nanoparticles (LNPs) for efficient mRNA delivery. This study aims to systematically evaluate clinically approved ionizable lipid DLin-MC3-DMA and SM102-based LNPs for ocular mRNA delivery, with a comprehensive assessment of their physicochemical characteristics, delivery efficiency, and biodistribution patterns within the ocular microenvironment. Enhanced green fluorescence protein or Luc encoding mRNA-loaded LNPs were formulated using microfluidic mixing technology and characterized by dynamic light scattering, ζ-potential measurements, and cryogenic transmission electron microscopy imaging. The two LNP systems with different ionizable cationic lipids demonstrated distinct capabilities for <i>in vitro</i> mRNA transfection and intraocular mRNA delivery following intravitreal administration. Notably, the SM102-LNPs exhibited superior performance compared to the MC3-LNPs, characterized by significantly higher transfection efficiency in retinal cells <i>in vitro</i>, and more efficient ocular expression with minimal systemic distribution <i>in vivo.</i> Safety assessment demonstrated that intravitreal administration of SM102-LNPs maintained excellent long-term biocompatibility throughout a five-month study period. The superior performance of SM102-LNPs establishes a promising platform for ocular mRNA therapeutics.