Engineering Cell-Selective ChargeAltering Lipid Nanoparticles for Efficient siRNA Delivery in Vivo

Lipid nanoparticles (LNPs) have emerged as a powerful platform for RNA delivery; the chemical engineering of LNP for efficient delivery of RNA into cytosol remains critical but challenging. One promising strategy is the use of permanently positively charged lipids, which have been shown to enhance the stability and delivery efficiency of LNPs. However, the resulting strong electrostatic interactions reduced the RNA release capacity from the lipoplexes. Herein, we engineered a hydrogen peroxide (H2O2)- triggered charge-altering LNP (CALNP) for efficient small interfering RNA (siRNA) delivery and tumor therapy in mice. The incorporation of phenylboronic acid (PBA) into ionizable lipids generated permanently positively charged lipids. A CALNP with optimal lipid formulations was identified, exhibiting enhanced transfection efficiency with effective lysosomal escape through dual effects of electrostatic interaction and ligand-receptor binding. H2O2-trig- gered removal of PBA groups regenerated ionizable LNP with reduced positive charges at physiological pH, allowing cell-selective siRNA release in the cytoplasm. Our results demonstrated that CALNPs exhibited improved siRNA transfection and gene silencing efficiency. We also showed potent CALNP activity against the polo -like kinase 1 (Plk1) gene by effectively silencing Plk1 mRNA and subsequent suppression of tumor growth. Collectively, these findings highlighted the potential of CALNP as an efficient platform for RNA delivery and tumor therapeutics.