Pu Shi, Haikun Liu, Ahmed Refaat, Thanh Nguyen, Anne Nguyen, Kaiting Miao, Yuyang Song, Sylvain Trépout, Rico F. Tabor, Liliana de Campo, Karlheinz Peter, Mark Louis P. Vidallon, Xiaowei Wang
mRNA nanotherapeutics hold immense potential for treating a wide range of diseases, but their widespread clinical adoption is limited by current lipid nanoparticle (LNP) delivery platforms, which frequently face challenges such as limited biocompatibility, immunogenic response, insufficient mRNA delivery efficacy and stringent cold-chain requirements. In this study, we systematically screened a 20-member lipid mixture library by substituting ionizable lipids and sterol components to identify formulations with improved physicochemical and biological profiles. A lead candidate combining γ-oryzanol and DLin-KC2-DMA as LNPs, termed OryKL (or KO 12 LNPs), was identified, exhibiting spherical bleb-type and core-shell nanostructures (∼150 nm), high mRNA encapsulation, and significantly enhanced in vitro transfection efficiency compared to cholesterol-based controls. Intravenous administration of OryKL delivered Cre recombinase mRNA effectively across multiple organs in Ai9 reporter mice, resulting in distinct cell-level tropism, and no detectable toxicity or inflammation, as confirmed via qPCR, organ histology, hematological assessment and liver function tests. Additionally, OryKL retained transfection potency for at least 60 days in lyophilized form with 20% (w/v) sucrose, supporting ambient-stable storage. These findings establish γ-oryzanol as a promising sterol alternative and position OryKL as a biocompatible, effective, and storage-stable platform for next-generation mRNA therapeutics.