PEG-Lipid Interfacial Architecture Enables Zn²⁺-Dependent Redistribution of LNP-Mediated mRNA Expression Toward the...

PEG-lipid interfaces influence LNP nano-bio interactions, yet conventional PEG-lipid formulations differ simultaneously in several molecular features that complicate attribution of ion-dependent effects. Here, using structurally defined DMA-PEG₁₆-OMe as a discrete PEG-lipid model and conventional DMA-PEG_2k-OMe as a comparator, we show that Zn²⁺ addition produces a concentration-dependent redistribution of organ-associated LNP-mediated mRNA expression from the liver toward the spleen. This redistribution was most pronounced in the PEG₁₆ formulation and was not observed to the same extent in the conventional PEG_2k formulation, supporting PEG-lipid interfacial architecture as an important determinant of the Zn²⁺-dependent response. Mechanistically, Zn²⁺ is associated with protein-corona remodeling, including enrichment of apolipoprotein H (ApoH; β₂-glycoprotein I), a corona component previously linked to splenic tropism, together with reduced inflammatory transcriptional activation. In a prophylactic B16F10-OVA-luc challenge model, Zn@PEG₁₆-LNP treatment was associated with improved tumor control, higher total serum IgG and IgG1 signals, and stronger SIINFEKL-responsive CD8⁺ T-cell responses. Together, these findings identify PEG-lipid interfacial architecture and Zn²⁺ incorporation as a simple formulation strategy for spleen-directed mRNA delivery.