其中,稀释方法对mRNA/LNP的影响仍缺少系统研究。目前生产放大中主要存在两种稀释策略:离线稀释(OD)先将新鲜制备的LNP收集后静置,再进行稀释;在线稀释(ID)则在混合之后立即引入稀释缓冲液,快速降低乙醇浓度。最近,上海交通大学附属仁济医院杨太华团队和迈安纳黄雷团队在药剂学顶级期刊 Journal of Controlled Release 发表名为“Dilution mode acts as a critical process parameter that reprograms lipid nanoparticle assembly and in vivo mRNA delivery”的最新研究。本研究采用DOE策略,系统比较了两种代表性的稀释方法,在不同流速(FR)、流速比(FRR)和稀释比(DR)条件下的区别,旨在明确稀释方式能否作为 LNP 结构-功能关系的独立影响因素,并重新定义其在LNP生产放大中的角色。
迈安纳微流控XNano系列设备及试剂盒
01实验结果 稀释方式对 mRNA/LNP 理化性质的影响
研究按照 L9(3⁴)DOE 表,在 9 种不同微流控混合工艺条件下(P1–P9)系统比较不同稀释工艺对 SM-102 mRNA/LNP 理化性质的影响。结果显示,即使在微流控混合条件完全相同的情况下,两种稀释方式仍产生了显著不同的理化特征:ID 在九个条件中的七个条件下产生更小的颗粒,剔除呈相反趋势的 P7 后,ID 粒径较 OD 显著降低 19.8%(91.1 vs. 115.7 nm,p < 0.001,Fig. S2A);PDI 总体相近。多数条件下 ID 的包封率(EE)更低,剔除 P1 后 OD 的 EE 显著高于 ID(83.3% vs. 63.3%,p < 0.05,Fig. S2C);Zeta 电位随 EE 呈相似趋势。除 SM-102 脂质之外,本研究还考察了不同稀释工艺对 ALC-0315 和 Lipid-5 两种可离子化脂质的影响(Fig. S3),结果显示稀释工艺由 OD 切换为 ID 同样引起 ALC-0315 和 Lipid-5 LNP 粒径与 EE 的降低,表明粒径和 EE 下降是 ID 过程的普遍性结果,而非 SM-102 依赖的现象。
Table 1. Mixing and dilution methods of mRNA/LNP
Fig. 1. Influence of dilution methods on the physicochemical properties of mRNA/LNP. (A) Schematic of the LNP preparation method with different dilution methods. Comparison of mRNA/LNP prepared by OD and ID regarding (B) size, (C) PDI, (D) EE, (E) Zeta potential.
Fig. 2. Influence of dilution methods on the in vitro/in vivo performance of mRNA/LNP. Comparison of mRNA/LNP prepared by OD and ID regarding (A) DC2.4 expression, (B) C2C12 expression, (C) AML12 expression. In vivo expression of mRNA/LNPs prepared by OD (D) and ID (E) after i.m. injection. Comparison of mRNA/LNP prepared by OD and ID regarding (F) muscle expression, (G) liver expression, and (H) the liver-to-muscle ratio.
Fig. 3. Effect of dilution and mixing method on cellular uptake of mRNA/LNPs. (A) Fluorescent images of AML12 cells treated with various mRNA/LNP formulations, scale bar = 45 μm. Quantification of Cy5 MFI in AML12 cells, analyzed by (B) mixing methods and (C) dilution methods. (D) Influence of DR on Cy5 MFI in AML12 cells under OD conditions.
Fig. 4. Effects of dilution method on lysosomal co-localization of mRNA/LNP. (A) Images of AML12 cells treated with various mRNA/LNP formulations, scale bar = 10 μm. Quantification of colocalization of Cy5 and FITC, analyzed by (B) dilution methods and (C) mixing methods. (D) Influence of FRR on colocalization in AML12 cells. (E) Influence of FR on colocalization in AML12 cells under ID conditions.
Fig. 5. Effects of dilution and mixing method on mRNA/LNP morphology. (A) Morphology characterization of mRNA/LNP, scale bar = 100 nm. (B) Quantification of bleb ratio. (C) Influence of DR on bleb ratio. (D) Correlation between bleb ratio and luciferase expression in muscle after i.m. injection.
Fig. 6. Effects of dilution and mixing method on spike-specific IgG antibody and IFN-γ ELISpot responses elicited by mRNA/LNPs. (A) Schematic outline of the experimental protocol. Spike-specific antibody levels analyzed by the mixing method (B) and dilution method (C). (D) Comparison of ELISpot counts between OD and ID methods. Normalized ex vivo IFN-γ ELISpot counts for the spike antigen in splenocytes analyzed by the mixing method (E) and dilution method (F). (G) Correlation between ELISpot counts and particle size.
参考文献:Tang S, Huang L, et al. Dilution mode acts as a critical process parameter that reprograms lipid nanoparticle assembly and in vivo mRNA delivery. [J]. Journal of Controlled Release, 2026, 115365. DOI: 10.1016/J.JCONREL.2026.115365.