Gold Nanoparticle–mRNA Conjugates Encapsulated in Lipid Nanoparticles for Coordinated Codelivery of Multiple mRNAs

Gold nanoparticles (AuNPs) can be engineered to be utilized as carriers via anchoring multiple nucleic acids, including mRNAs, in specific ratios. However, the negative charge of mRNA–AuNP conjugates presents significant challenges for efficient cellular uptake and subsequent expression. To overcome this limitation, we developed a delivery system that combines mRNA–AuNP conjugation with lipid nanoparticles (LNPs) to enhance intracellular delivery. In our approach, AuNPs were functionalized with a thiolated antisense leader sequence (ALS), oligonucleotides complementary to the 5′-end leader sequence of the 5′-untranslated region (UTR) of the mRNA. This functionalization resulted in the formation of mRNA–ALS–AuNP conjugates, which were then encapsulated within LNPs. When we compared the ALS-AuNP@LNP constructs to ALS–AuNPs alone, ALS-AuNP@LNP demonstrated superior delivery and expression of enhanced green fluorescence protein (EGFP) mRNA across multiple cell lines, as evidenced by robust green fluorescence. Furthermore, this system enables the precise codelivery of multiple mRNAs in defined ratios, as demonstrated by the successful codelivery of EGFP and mCherry mRNAs. These findings highlight the potential of the mRNA-ALS-AuNP@LNP platform as an effective and versatile tool for advancing mRNA-based therapeutics and vaccine development.